College of Physicians and Surgeons, Columbia University, New York, New YorkBACKGROUND. The most common type of donor closure in hair transplantation is with non-absorbable, running sutures, usually of nylon or polypropylene. This is accomplished with, or without, buried absorbable sutures. Another popular method of closure is with stainless steel staples. Each of these methods has benefits and limitations with respect to healing, comfort and convenience for the patient.METHODS. Poliglecaprone 25 (Monocryl) is a synthetic, absorbable monofilament suture of low tissue reactivity. It was compared to closure with metal staples in a bilateral controlled study. One side of the donor area was closed with Poliglecaprone 25 sutures (4-0 Monocryl) using a running cutaneous stitch and the other side was closed with stainless steel staples (3M-Precise DS-25). Patients were evaluated with regard to healing, post-operative discomfort, resultant surgical scar, and closure material preference.RESULTS. Of the 22 patients studied, the following post-op complaints were noted on the staples side; tenderness (12), itching (4), swelling (2) and scabbing (1). This compared to only one complaint of itching and one complaint of swelling on the Monocryl side. Two patients had post-operative complaints of visibility of staples showing through their hair. Objective measurements revealed a wider scar overall on the staples side in six patients and wider scar on the suture side in 2 patients. The average scar width on the staples side measured 1.78mm compared to a 1.42mm on the sutures side. Fourteen of the 22 patients preferred Monocryl for future procedures; one preferred metal staples and 7 had no preference. Most patients stated that post-operative discomfort from the staples and the inconvenience and occasional pain associated with their removal was responsible for their decision.CONCLUSION. Poliglecaprone 25 (Monocryl) is a strong synthetic, absorbable, monofilament suture with low tissue reactivity that can be used in hair transplantation to close the donor wound with a single, running cutaneous stitch. This suture can provide a donor closure that ensures hemostasis, has little risk of infection and is comfortable for the patient. If specific surgical techniques are followed, this suture can provide a donor closure that ensures hemostasis has little risk of complications, is both comfortable and convenient for the patient post-op, and results in a fine surgical scar.THE IDEAL SUTURE should be strong, handle easily and form secure knots. The ideal wound closure should ensure hemostasis, have a low risk of infection, be comfortable for the patient, and result in a fine surgical scar. 1,2 A fine scar in the donor region following a hair transplant is especially important since it gives patients flexibility in styling and the option to wear their hair relatively short. It also allows for efficient harvesting of hair in subsequent procedures, thus maximizing the total donor supply.The most common type of donor closure in hair transplantation is with non-absorbable, running sutures, usually of nylon or polypropylene (Prolene, Surgilene). This is accomplished with, or without, buried absorbable sutures, usually of polyglactin 910 (Vicryl) or Polyglycolic acid (Dexon). This method of closure provides good control of wound edges and is relatively fast, especially when moderate to large bites are used. Larger bites keep the sutures from becoming buried during the healing phase and make their removal easier.In spite of their popularity, there are several problems associated with this type of closure. The running suture has the tendency to strangulate tissue and compromise the blood supply to the wound edges. This can be problematic when the closure is under tension or when there is a significant amount of edema. The involved tissue will heal more slowly and may be more subject to infection. In addition, the hair follicles incorporated within the sutures may be shed and this hair loss may be permanent. Finally, although synthetic non-absorbable sutures have low tissue reactivity, they can cause mechanical inflammation if there is any tension on the wound.To minimize tissue strangulation, a running suture may be used with the bites placed very close to the wound edges. However, the problem with this technique is that, as healing progresses, the sutures quickly become buried and difficult and traumatic to remove. To circumvent the removal issue, absorbable sutures have been used in the cutaneous running stitch. Unfortunately, the commonly used absorbable sutures (gut, chromic, Vicryl and Dexon) all incite a considerable inflammatory reaction in the skin and this inflammation can be associated with permanent alopecia along the suture line.The purpose of this study is three-fold. First, to describe the use of Poliglecaprone 25 (Monocryl), a synthetic, absorbable, monofilament suture3,4 in hair transplantation surgery. Second, to detail the suturing techniques needed to maximize the benefit of this suture. Third, to compare this material and suturing technique to another type of closure, that of metal staples.Poliglecaprone 25 has the chemical structure (C2H2O2)m(C6H10O2)n, which forms a complex polymeric chain giving Monocryl its special properties. The monofilament is comprised of a soft segment that consists of a random co-polymer of -caprolactone and glycolide that provides good handling characteristics. A hard segment, composed of polyglycolide, gives the suture its strength.3 As a result; the suture possesses excellent handling and knot security, minimal resistance as it passes through tissue, and the highest tensile strength as compared to other absorbable monofilament sutures3,4,5.Poliglecaprone 25 has been shown to be non-toxic and non-allergenic and without pyrogenic or hemolytic potential.3 The synthetic material is slowly broken down by the body via hydrolysis and therefore incites little inflammatory reaction in the skin. The reduction in the tensile strength of Monocryl, as it is absorbed over time, is consistent with the requirements of most hair transplant surgery procedures 3,4Stainless steel staples were chosen for the comparison since they have the advantage of being totally inert, not causing tissue strangulation, being fast to apply, and having been reported to result in excellent healing.6,7We performed a bilateral controlled study designed to compare donor wound closure using Poliglecaprone 25 sutures (Monocryl) with a closure using stainless steel staples. Patients were evaluated with regard to post-operative course, resultant surgical scar and suture preference. We will also discuss some of our clinical experience in using this new suture material.Methods and MaterialsFollicular Unit Transplantation was performed on 22 adult male volunteers; in sessions ranging from 600 to 2500 grafts using previously published methodology 8,9,10. All patients were undergoing their first hair transplant procedure. Donor anesthesia was established with a ring block of 10-15cc of a solution containing 60% Lidocaine 0.5%, 40% Bupivicaine 0.25%, and 1:200,000 epinephrine. Donor tumescence was achieved by infiltrating 20-30cc of Lidocaine 0.17% with 1:600,000 epinephrine into the subcutaneous space using 10cc syringes and 25g needles.Approximately 2-3 minutes after the tumescent mixture was administered, a donor strip was harvested using two parallel blades set on a Rassman handle 1.2cm – 1.5cm apart. (The handle pre-angles the blades at 30o to follow the direction of the emerging hair). In the protocol procedures, the strip widths ranged from 0.9 to 1.3cm and the lengths from 6 to 25cm (measurements taken after the strips were harvested). The ends of the donor strip were equidistant from the midline.One side of each donor area was closed with Poliglecaprone 25 suture (Monocryl 4-0, PS-1 cutting needle, 70cm length, Undyed). The contra-lateral side was closed with stainless steel staples (3M-Precise DS-25) On the sutured side, a single running 4-0 Monocryl suture was used. The bites were spaced approximately 0.5cm apart and the suture was advanced on the surface, rather than under the skin (as in traditional surgery), in order to minimize the amount of suture in contact with the follicles (see discussion section). The needle was passed through the full thickness of the dermis and exited the wound edge just below it (at the level of the bulbs) without incorporating any significant amount of subcutaneous tissue. The needle track was kept parallel to, and within 1.5mm of the wound edge Since the upper wound edge is cut at a 30o angle, the needle must penetrate the skin with an “upward” motion (with the patient in a sitting position) so that the needle remains parallel to the wound edge though its entire course through the tissue. Occasionally, the upper wound edge will be distorted by the elastic retraction of the dermis so that the upper wound edge may require slight eversion with rat-tooth forceps for proper suture placement. This is usually not required for the lower edge where needle placement is easier.The wound edges on the stapled side were approximated with a skin hook grasping the lower edge and rat toothed forceps grasping, and slightly everting, the upper edge (This required the help of an assistant). Once the wound edges were flush, the staples were applied in such a fashion that the middle of the staples rested slightly above the incision line. This permits a better grasp of the upper wound edge whose edge is thinner due to the acute angle of the blades. The staples were placed approximately 0.6cm apart. Patients were evaluated for post-op complications, discomfort, and resultant surgical scar. Recorded observations were made on follow-up visits 10-14 days and 6-8 months post-op. Staples were removed at the 10-14 day post-op visits. The sutures were left in place. Post-op complications and post-op discomfort were assessed via questionnaires filled-out by the patients at the time of their follow-up visits. The surgical scar was evaluated subjectively with questions on donor area cosmesis and objectively by measuring the width of the donor scar at multiple points along the suture-line. Finally, all patients were asked the question, “Which suture would you prefer to be used in future procedures”?ResultsThe results of the 22 patients in our study are summarized in Table 2. The following post-operative complaints were reported on the staples side; tenderness (12 patients), itching (4 patients), swelling at the suture line (2 patients) and scabbing (1 patient). This compared to two post-op complaints from the Monocryl side; itching (1 patient) and swelling (1 patient).Of the 22 patients studied, one patient reported post-op bleeding on the staples side and one noted it on the sutures side. Further questioning, however, revealed that these patients had only experienced some blood on the post-op dressing. There was never any active bleeding noted by any patient in the study, any that required intervention on the part of the patient, nor any that prompted a call to the physician. There was no infection or wound dehiscence on either side.Since it was difficult for patients to directly assess their donor scar, we used an indirect method that we labeled “donor area cosmesis.” This had three components; visibility of the suture material in the immediate post-op period (0-2 weeks), the inability of the patient to wear his hair as short as he had been accustomed to in the more extended post-op period (4-8 months) and, finally, any perceived hair loss along the suture line. Only two patients had post-operative complaints regarding cosmesis, both related to visibility of the actual staples through the hair. No patients had any problems with wearing their hair short in the more extended post-operative period and none had any perceived hair loss from either type of closure.Donor scars were measured in multiple points to assess the widest, narrowest and average widths. Measurements revealed a wider scar overall on the staples side in six patients and wider scar on the suture side in 2 patients (Figures 6A,B,C). The average scar width on the staples side measured 1.78mm compared to a 1.42mm on the sutures side. (Refer to Table 2 for the average minimum and maximum scar widths from each type of closure.)The final parameter was a subjective global assessment by the patient regarding suture preference. In response to the question “Which suture would you prefer to be used in future procedures”? 14 of the 22 patients preferred Monocryl, one preferred metal staples and 7 had no preference. The reason behind their choice was explored in more detail in the “comments” section of the questionnaire. Most patients stated that post-operative discomfort from the staples and the inconvenience and occasional pain associated with their removal was responsible for their decision. It is important to note that in the comments section, five patients qualified their answer by stating that, in spite of their preference, they would choose the side that gave the best results when undergoing future procedures.DiscussionThe ideal wound closure should ensure hemostasis, have a low risk of infection, be comfortable for the patient post-op, and result in a fine surgical scar. A fine scar in the donor region following a hair transplant is especially important since it gives the patient flexibility in styling and the option to wear the hair relatively short. It also allows for efficient harvesting of hair in subsequent procedures, thus maximizing the total donor supply.Since March 1998, we have been closing the donor site of the majority of our hair transplant patients with a single, running cutaneous suture using poliglecaprone 25 (Monocryl). The suture, a synthetic, absorbable, monofilament with low tissue reactivity, appears to have some distinct advantages over other types of materials. We reported our preliminary results with this suture at the International Society of Hair Restoration Surgery, 7th Annual Meeting, San Francisco, CA in October 1999.Poliglecaprone sutures are made from a co-polymer of glycolide and caprolactone. This synthetic material is broken down by the body via hydrolysis and therefore doesn’t incite the typical inflammatory reaction characteristic of other absorbable sutures. Because of this, the suture can be used to oppose tissue at the level of the hair follicles, without the risk of significant damage to these structures. In addition, the translucent sutures are skin colored and are barely visible once the donor area is sutured closed.In our experience, carefully harvesting the donor strip by superficial dissection in the mid-fat layer, followed by meticulous approximation of wound edges under little tension, and placing sutures very close to the wound edges, will maximize the chance of a fine scar. A superficial incision that spares fascia will allow for a superficial closure and allow healing without the dermis being bound to the deeper tissues. This will help preserve scalp laxity for subsequent procedures and possibly minimize post-op edema by causing less interference with lymphatic drainage.Placement of sutures within 1.5 mm of the free edge will provide for excellent dermal to dermal contact and perfect wound edge apposition, without the incorporation of unnecessary tissue and associated hair follicles. This allows the blood supply to reach the edges of the wounds unimpeded and also prevents any post-op edema that might place tension on the sutures and strangulate the tissue. This is especially important in large hair transplant sessions that can be associated with significant amounts of post-operative edema that can compress hair follicles entrapped in the running sutures and cause permanent alopecia When a running stitch is used in traditional skin surgery, the surgeon advances the suture as it travels through the subcutaneous tissue so that, on the surface of the skin, the visible parts of each loop appear perfectly parallel. Under the skin, however, each suture takes a diagonal course. The reason for this is twofold. The first is to have a more organized “neater” appearance and the second is to minimize any suture marks on the skin surface. In scalp surgery, the goal is just the opposite. When operating in a hair-bearing area, the object is to minimize the amount of suture in contact with the follicles to prevent hair loss. Therefore, the sutures should run parallel in the fat (so that they don?t cross over and entrap follicles) and be advanced on the surface where any transient suture marks on the skin are irrelevant.When using small bites very close to the wound edge, sutures tend to get buried within several days after the surgery and become problematic to remove at 1-2 weeks. Poliglecaprone offers a distinct advantage over non-absorbable sutures since they don?t need to be removed.A more subtle advantage of placing sutures close to the wound edge is that it allows for a greater surface area that can be stretched to close the wound. When large bites are used the elasticity of the skin between the sutures actually pulls the edges away from each other, making approximation more difficult and the wound tension greater.Recently, Kolasinski described using a running intra-dermal Monocryl suture to close the donor area11. This technique has the benefit of avoiding tissue strangulation, but has the disadvantage of a less secure apposition of the wound edges. In addition, it is a more laborious technique. Our limited experience with this suturing method suggests that it may have an advantage over a simple running stitch in very short incisions with no tension, but is inferior for the majority of closures in our practice. Bilateral comparisons need to be made to determine the ideal indications for each technique.Another advantage of Poliglecaprone suture is the in-vivo duration of its tensile strength. Its initial strength is comparable to that of the very strong, non-absorbable suture polypropylene. At 7 days it maintains 50-60% of its tensile strength and at 14 days (the longest time that non-absorbable sutures are generally left in place) it still has 20-30% of its strength. In situations when there in no undue tension, this permits the wound to be closed without the need for buried sutures. This has the advantage of a shorter operating time and eliminates the possibility that subcutaneous sutures can impinge upon and damage hair follicles.Because of the excellent tensile strength of Monocryl sutures, we were able to close all of our wounds with 4-0. In non-study patients, with short incisions under no tension, we have occasionally used 5-0 with excellent results. The important point is that using heavier Monocryl sutures (i.e. 2-0 or 3-0) is unnecessary and will result in more inflammation, poorer wound healing and complaints of slow absorption by the patient. As with taking large bites, using a suture heavier than 4-0 will negate many of the benefits of using Monocryl and is strongly discouraged by these authors.Table 3. Guidelines for Using Monocryl Sutures- Plan width of donor strip so that there is little or no tension on closure.- Use tumescent anesthesia to harvest donor strip in mid-fat.- Use sutures no heavier than 4-0 or 5-0 gauge.- Use a simple running stitch, advancing each loop on the skin surface.- Keep needle parallel to, and within 1.5 mm of wound edge.- Incorporate epidermis and dermis only.- Use 0.5cm spacing between loops.In this study, metal staples were chosen for the comparison because they are totally inert, do not cause strangulation of the wound edge, are fast to apply, and have been reported to result in excellent healing6,7. However, our study has shown that they have the disadvantage of being uncomfortable for patients in the post-operative period. In addition, they require a follow-up visit for their removal (which also can be very uncomfortable) and most importantly, result in a wider scar than sutures in most patients when there is even minimal wound tension. In addition, we found that although fast to apply, staples did require some degree of skill to apply properly and required an assistant to hold the wound edges perfectly flush as the staples are applied.Staples did not appear to hold the wound edges as securely as sutures, so that there was slightly more post-op oozing (this was observed in our practice, but not in the study). In addition, in some patients, neck flexion caused the edges to shift slightly resulting in a slightly perceptible ridge along the suture line (this was never observed with sutures). Finally, staples produced a very distinct linear scar and, even when it was very fine, did not blend in as well with the surrounding hair, as did the scar resulting from Monocryl sutures.Staples produced a measurably finer scar in two patients in the study. Both of these patients had high density and very loose scalps. This has been consistent with the general experience using staples in our practice. It appears that staples offer a slight, but definite, advantage in these select patients. In our practice, we presently offer the choice of staples to patients who fall into this category of high density and good scalp laxity and who, in addition, are undergoing a relatively small procedure (requiring a donor incision of 14 cm or less).The best explanation for the generally superior healing with Poliglecaprone sutures over metal staples is the ability to consistently achieve perfect wound edge approximation when sutures are meticulously placed.The experience in our facilities, where over two thousand patients have had closures using Monocryl sutures, has been that Monocryl has a slightly greater incidence of pruritus than the less than 5% reported in this study. We find that the true incidence is probably on the order of 10-20%. The small n value of this study would likely account for this difference. Post-operative pruritus can be greatly reduced by keeping the suture line occluded with a thin layer of ointment of any kind (we routinely use Bacitracin Ointment) for 2-3 weeks following surgery. It is important to note that, in the current study, excluding tenderness, there was little difference in side effects between the two sides.A complaint from some patients in our practice, that was not reported by any patients in the study, was persistence of the knots at the ends of the running Monocryl suture. All patients are told pre-operatively that, although the sutures will have lost their strength by three weeks post-op, the knots may persist longer. When the knot persists longer than three weeks it is usually because some hair was incorporated into the knot during the suturing. Since the knot is not subject to hydrolysis by the body, it will sit on the surface of the scalp until it loosens from the hair. The most likely explanation for the difference in the rate of complaints between our general patients and those in the study is the greater attentiveness to pre-operative discussions by patients enrolled in the study and thus the greater awareness that this might occur. After two weeks, any patient complaining of a persistent knot is advised to either return to the office for removal or instructed to simply cut the knot off with fine scissors at home.In summary, Poliglecaprone 25 (Monocryl) is a very strong synthetic, absorbable, monofilament suture with low tissue reactivity that can be used in hair transplantation to close the donor wound with a single, running cutaneous stitch. If specific surgical techniques are followed, suturing with Monocryl can produce a fine surgical scar superior to metal staples and can result in a more comfortable post-operative experience for the patient.Acknowledgement This work was performed at the New Hair Institute, 125 East 63rd St., New York, New York, and 2150 Center Ave., Fort Lee, New Jersey.References1. Bennett RG: Selection of wound closure materials. J Am Acad Dermatol 1988; 18: 619-37.2. Moy RL, Waldman B, Hein DW: A Review of Sutures and Suturing Techniques. J Dermatol Surg Oncol 1992; 18: 785-95.3. Bezwada RS, Jamiolkowski DD, Lee I-Y, et al: Monocryl suture, a new ultra-pliable absorbable monofilament suture. Biomaterials 1995; 16: 1141-48.4. LaBagnara Jr. J: A review of absorbable suture materials in head and neck surgery and introduction of Monocryl: a new absorbable suture. ENT J 1995; 74(6): 409-15.5. Nahai F, Bried JT: Evaluation of the Monocryl suture for skin closure in 100 plastic surgery patients. Perspectives in Plast Surg 1995; 9(1): 1-4.6. Stegmaier, OC: Use of skin stapler in dermatologic surgery. J Am Acad Dermatol 1982; 6: 305-9.7. Stough DB, Haber RS. Hair Replacement: Surgical and Medical. St. Louis: Mosby-Year Book, Inc., 1996: 136-7.8. Limmer BL. Elliptical donor stereoscopically assisted micrografting as an approach to further refinement in hair transplantation. Dermatol Surg 1994; 20: 789-93.9. Bernstein RM, Rassman WR: Follicular Transplantation: Patient Evaluation and Surgical Planning. Dermatol Surg 1997; 23: 771-84.10. Bernstein RM, Rassman WR: The Aesthetics of Follicular Transplantation. Dermatol Surg 1997; 23: 785-99.11. Kolasinski J: Monocryl suture in hair transplantation. Hair Transpl. Forum Int. 2000; 10(3): 77-8.Dr. Bernstein is Clinical Professor of Dermatology at Columbia University in New York. Dr. Bernstein’s hair restoration center in Manhattan is devoted to the treatment of hair loss using his state-of-the-art <a href=”http://www.bernsteinmedical.com/hair-transplant/index.php”>surgical hair restoration</a> techniques. To read more publications on hair loss, visit http://www.bernsteinmedical.com/.

As with any design process, aesthetics plays a large role in determining the final outcome of a hair transplant. Just as a sculptor must consider aesthetic concepts that are familiar to his or her audience, a hair transplant surgeon uses aesthetic principles to create a natural looking result for the patient.For the most part, the correct template for hairline placement, hair distribution and density during a hair transplant has already been supplied by nature. The closer one follows the pattern set by nature, the more natural the results of the hair restoration will appear. Any hair transplant — no matter how dense or how perfectly executed — will look artificial unless it produces head of hair that others can recognize as one they have seen before. Just as the follicular implant attempts to mimic the way hair grows in nature on a microscopic level, the overall design of the follicular implantation should strive to mimic nature on a gross level. The Frontal Hairline and Other Transition zones -The transplanted hairline must be restored to a position appropriate for a mature adult since, in contrast to one’s original hairline, it will not change its position or shape over time. In a mature adult, the mid-portion of the frontal hairline is approximately one finger-breadth (1.5-2 cm) above the brow crease. Temple recession is more variable in the normal adult hairline so there is significant flexibility in designing this area. As a general rule, if a hair transplant patient wants to wear his hair combed straight back, a hairline with more temporal recession will give a denser, fuller look. With side-to-side grooming, a broad hairline will look fuller. The key to producing a natural hairline is to create an irregular saw-tooth, or zigzag pattern, at the leading edge. It is more common to error by making the hair line too uniform than by making it too irregular. Besides being irregular, a hairline should also be slightly asymmetric. The hair transplant will look most natural if one side is shaped, and positioned, slightly different than the other. As a very general rule in choosing which side to make lower, it is often best to make the part side slight lower than the contra lateral side. Particular attention should be paid to facial asymmetry as this will often influence the position of the hairline. Transition zones must be created wherever the edge of the transplanted area is visible. This occurs at the frontal hairline, in the crown, and in the part area on the sides of the scalp. In a typical surgical hair restoration procedure, approximately 200-250 one-hair follicular units are used for the front edge of the hairline. This is immediately followed by two-hair follicular unit grafts. The three- and four-hair units are concentrated in the forelock area, but should extend lateral and posterior in patients with higher density. In all locations, one- and two-hair follicular units should be placed peripheral to the larger grafts to insure a soft, natural appearance. Hair Direction -Particular attention should be paid to the angle of the recipient sites, since this will determine the ultimate direction that the hair will grow. Hair should be placed into the scalp at the angle it originally grew, not in the direction that it is to be groomed. In general, hair anterior to the vertex transition point should point forward, with the angle of the hair (with respect to the surface the scalp) becoming more acute as one approaches the anterior hairline. At the frontal hairline, the emergent hair is essentially horizontal to the ground (regardless of the slope of the forehead). The direction of hair in the frontal hairline continues to point forward until it approaches the temples where it abruptly changes to a downward anterior and then, at the apex of the temples, to a downward posterior direction. Two common mistakes are to transplant the hair radially at the hairline, rather than forward and to follow the direction of a lick or swirl that would otherwise disappear as the patient continued to bald.Hair should point forward until it reaches the vertex transition point, the area in the posterior aspect of the scalp where the horizontal and vertical planes meet. At this point, the hair changes direction from a predominantly anterior to a radial direction, forming the crown whorl. This point is important in that it represents a natural stopping point for the hair transplant when the donor reserves are limited. Distribution -The area of the scalp subject to androgenetic alopecia can be divided into three regions: 1) the frontal hairline and frontal scalp, 2) the top or mid-scalp and 3) the vertex or crown. The vertex transition point separates the top of the scalp from the crown. Since the frontal area of the scalp provides the greatest cosmetic impact, this area should have the greatest hair density. This can be accomplished by placing recipient sites in this area closer together (forward weighting). Greater density can also be achieved by placing larger follicular units, i.e. those containing 3- and 4 hairs, in the forward/central part of the scalp (the forelock region). The larger units should not be used at the hairline, so that this zone will remain soft and natural, and they should not be evenly distributed across the scalp, as this will produce a diffuse rather than patterned look. The density should gradually decrease towards the crown. Most hair restoration patients have enough donor hair to allow the surgeon to extend the transplant to the vertex transition point. As mentioned, this is a natural stopping point since, even if the crown continues to enlarge, transplants performed to this point will maintain a natural appearance, even without additional surgery. Hair transplants should be extended past the vertex transition point into the crown only when the doctor is relatively certain that there will be an adequate donor supply to create a swirl and follow the hair loss laterally if the balding progresses. Although the transplanted hair direction should not be based upon the way a person intends to groom his or her hair, there are other aspects of transplant design that should be influenced by hair styling preferences, if this is known in advance of the procedure. The degree of temple recession has already been mentioned. Another decision is graft weighting. In general, the grafts should be forward weighted in the anterior-posterior direction, and symmetrically distributed from left to right. However if a hair restoration patient is relatively certain that they will comb their hair to the side, or diagonally backwards, then hair may be weighted on the part side to give the appearance of greater fullness. This may be accomplished by creating recipient sites more closely together on the part side, by placing larger follicular units in this area, or by doing both. When using larger follicular units, it is important to still create a soft transition zone of one and two-hair units at the visible edge of the part. It is difficult for patients, particularly those who are extensively bald, to know how they will comb their hair after the transplant. Because of this, it is best to transplant the first session in a symmetrical pattern. However, once the session has grown in, if they are relatively certain that they will continue to groom their hair in one specific way, subsequent sessions can be weighted to one side for greater fullness. Transplanting the first session symmetrically will help insure that there are no gaps in the distribution and that the weighting will not be at the expense of a natural look. Regular vs. Dense Packing -It is generally accepted that transplanting up to 25 follicular units per cm2 will not impede their growth. Although there are few well controlled studies addressing the issue, many practitioners feel that “dense packing,” as defined by densities above 25 follicular unit/cm2 grafts, may risk graft survival when performed in large hair transplant sessions and in certain patients. Until there are good scientific studies to clarify this issue, it is probably prudent to consider the following: 1. There is probably significant patient-to-patient variability in the ability to support grafts that are densely packed.2. Significant solar damage, which alters the cutaneous vasculature, is a relative contraindication to dense packing.3. Densely packed grafts are more difficult to place and have a greater risk of popping than more generously spaced grafts.4. Dense packing should be considered when the majority of follicular unit grafts can fit into recipient site wounds no greater than those made with the equivalent of a 19-g hypodermic needle. 5. Dense packing is often performed by trimming grafts very closely and breaking up naturally occurring 4- and sometimes 3-hair follicular units.6. The additional density achieved with very dense packing may come at the expense of graft survival.One should consider that the average non-balding scalp has 100 follicular units per cm2 and that approximately 50% may be lost before there is any noticeable thinning. It would be wasteful, therefore, for more than 50% to be replaced — especially since hair transplants are always performed in the face of a limited donor supply. If the larger three- and four-hair units are placed in select areas, more than 25% of the initial density can be achieved in one pass of 25 follicular unit/cm2. With two procedures this density can be achieved in many hair restoration patients.Some physicians advocate a “one-pass” procedure to achieve the final density in one treatment session. Although this may be appropriate for some patients, the increased incidence of graft popping, desiccation, insertion injury and possible vascular compromise, may lead to poor growth. For very bald patients, very dense packing may not permit coverage of an entire bald area unless very large numbers of grafts are used. Until good scientific studies demonstrate that dense packing in very large hair transplant sessions will allow optimal growth in the majority of patients, covering the entire bald area with moderate density and then increasing density in a subsequent session may be a more judicious strategy, as this allows a natural distribution to be created in the first procedure and it avoids the potential risks associated with very dense packing or extremely large sessions. Coronal (horizontal) vs. Sagittal (vertical) Incisions -Follicular units emerge from the scalp in either a bundle or in a linear array. When in a linear configuration, the orientation is generally in a coronal (horizontal) plane, allowing the follicular units to shingle and provide more coverage than if they were sagittal or random. It has been argued that during a hair transplant there is less scar contraction with a coronal incision compared to a sagittal one. This would allow follicular units to remain linear after they have been transplanted and provide the rational for using coronally angled grafting (CAG) to best approximate the way hair grows in nature.The main advantage of CAG is that it would provide a fuller look to the transplant compared to traditional (sagittal) incisions. Another advantage is that grafts may be positioned at a more acute angle with the surface of the scalp and there may be less tendency of the growing hair to elevate in the vertical plane. This is particularly important at the temple/sideburn area where the hair lies very flat to the scalp surface. It is also felt by some practitioners that CAG exhibits less popping and that the wounds cause less damage to the vascular bed. Hair restoration doctors using sagittally angled grafts (SAG) feel that the pre-made vertical recipient sites are easier to see and that grafts are easier to place in these sites, minimizing injury to the follicular unit grafts. This may be particularly relevant in areas where there are significant amounts of hair present and the hair transplant surgeon does not have the luxury of shaving the scalp before the procedure. It has also been pointed out that coronal incisions (which cross Langer’s lines) potentially cause more damage to collagen and the cutaneous vasculature, than sagittal incisions. An additional concern is that, although there is possibly more hair elevation with sagittal than coronal incisions, there is less lateral (radial) splay of hair when the former is used. As with minimizing lift, minimizing lateral splay is also an issue of significant cosmetic importance. Finally, if one considers that many follicular units are not linear and that many linear units may indeed contract during the healing process and lose their linear orientation, CAG may offer only a theoretical advantage.At the time of this writing, there is no consensus on which method is best and if the differences are even significant for most patients, although there is a general trend towards CAG. As with many techniques used in surgical hair restoration, the advantage of one over the other may ultimately depend upon the particular patient, a particular transplant session, or the skills and preferences of a particular surgeon. A number of researchers are currently examining these issues; however, regardless of the outcome, considering the rotational orientation of follicular unit graft adds an important new dimension to follicular unit hair transplantation.

Dr. Jim Arnold should be congratulated on another excellent and detailed reporting of the ISHRS meeting. We appreciate the inordinate amount of time and effort that he has spent in recording the vast amounts of information that speed by us so quickly. It is amazing how he does it! In reading the article in the Nov.-Dec. 1997 Forum, Vol. 7, No. 6, p. 5, I noticed three small errors in the text that should be corrected. I thought that I might also take the opportunity to briefly discuss them.The text reads “Some patients may average 1or 2 hairs per unit, while others 4 to 5.” While we do see patients with very low density, or Asians, who average 1 or 2 hairs per unit, I have not seen patients who average 4-5 hairs per unit. Patients with high density can have a significant number of 4, or rarely 5 hair follicular units, but this is not their average. The graph that I presented in Barcelona, illustrating this point is shown here. Another important point is that the density (spacing) of naturally occurring follicular units is relatively constant at about 1 group/mm2 in the posterior scalp of most Caucasians, but is less in the Black races (where it averages approximately 0.6/mm2). The text also reads “Dr. Limmer finds the average number 2.3 hairs per unit, while Dr. Bernstein feels the number is closer to 3.” This is also incorrect. As I stated in my presentation, the majority of patients that we see in consultation that are surgical candidates range from 1.5 hairs/unit to 3.0 hairs/unit with an average of 2.0 hairs /unit (rather than 3). The population that actually go on to have surgery have slightly higher groupings at approximately 2.1/hairs per follicular unit. (The graph also illustrates this point). The numbers that I presented were based upon densitometry readings at the time of the consultation, taken approximately 5 cm to the left or right of the occipital protuberance. Only full-thickness terminal hairs were counted. Dr. Limmer and I spoke regarding the slight differences that we each observed and we felt that different patient populations might be a factor contributing to this small difference. The location on the scalp where the measurements were taken will also influence the results, as the follicular unit density is generally highest in the midline of the donor area and decreases laterally. Having prior knowledge of the approximate proportion of each of the different size follicular units that will be obtained in the dissection is extremely important in planning the transplant, since the larger units can be concentrated in select areas to create the appearance of greater central density without having to increase the “closeness” of the sites. These numbers are also important because the pre-operative measurement of density and the estimation of follicular unit size are two means of assessing the accuracy of the follicular unit dissection. The other statement “Hair diameter plays a significant role, as diameter may range by a factor of 5X among patients.” is also incorrect. The word “diameter” should be replaced with the words “Cross Sectional Area.” The range in terminal hair shaft diameter is approximately 2.3 fold (0.06 mm for very fine hair and 0.14 mm for the coarse hair that we often see in Asians). This represents a variation in x-sectional area of approximately 5.4 fold, since area = ~r2 or ~(1/2d)2. It is interesting to note that compared to hair density, hair shaft diameter plays a much more significant role in the volume or “bulk” of the transplant. The range in hair density in patients that we generally transplant is from 150 hairs/cm2 in those of low density, to around 300 hairs/cm2 for those with the highest. In our practice, we rarely transplant patients who present with a density of less than 150/hairs cm2 (except for Blacks and Asians) and uncommonly see patients with a density greater than 300 hairs/cm2. The range is thus a 2-fold difference. If we compare this to the 5.4 fold range in hair cross-sectional area, we see that, in theory, variations in hair diameter should have 2.7 times the cosmetic impact of variations in hair density. In reality, these variables are not totally independent. For example, the widest hair shaft diameters are not generally seen in the same patients who have the highest hair densities. Nevertheless, one can make a strong argument for the quantitative assessment of hair shaft diameter, as well as density, in the pre-operative evaluation of patients considering hair transplantation.

The past few decades have witnessed major changes in hair transplantation, most notably the trend towards the use of large numbers of very small grafts and the emergence of follicular unit transplantation as possibly the new “gold standard.” In addition to improved surgical techniques, new developments in medical treatments, marketing on the part of physicians, and coverage by the media, have produced an increased public awareness of this rapidly evolving field.The long-term observations of patients treated with the older hair transplant techniques and the use of new objective means to measure donor supply, have made the modern hair restoration surgeon more keenly aware of the importance of maximizing the patient’s finite donor reserves. As a consequence, new ways of harvesting and dissecting donor tissue have been developed to better preserve this supply, and new ways of handling and storing grafts awaiting placement have been devised to enhance the viability of the grafts. In addition, long-term planning has assumed greater prominence in surgical decisions. It is somewhat ironic that after four decades of wrestling with supply/demand issues, new medications for hair loss may soon necessitate a complete re-thinking of the way we plan our procedures.The use of large number of very small grafts has made the transplant process much more laborious and this has prompted the development of new technologies to automate various aspects of the transplant process. Long transplant sessions requiring greater numbers of staff and involving the movement of large numbers of small, fragile grafts has also made quality control a central issue.The decade has seen a dramatic decline in the popularity of scalp reductions and flaps, and fortunately the “pluggy look” that was once the hallmark of many older transplant procedures is now deemed to be unacceptable. Unfortunately, many patients still carry the telltale cosmetic deformities caused by the older techniques and “repair work” has become an increasingly larger part of many physicians’ practices.The initial excitement over laser assisted hair transplants appears to have subsided, because the very tiny sites needed in the newer procedures seems to be best made by cold steel incisions. However, laser technology is rapidly changing and this tool may still have a future role in hair transplantation, possibly in ways we have not yet considered.The development of 5-alpha reductase inhibitors and other medications that specifically attack the biochemical pathways involved in androgenetic alopecia will have a profound influence on the future of hair restoration surgery. Once drugs are able to successfully limit the extent of balding, supply/demand ratios will change, long-term planning may become less important and the aesthetic demands of all patients may substantially increase. As medications become more effective, their long-term safety profile established, and their use more widespread, it is possible that baldness may be preventable. When this happens, surgery may be reserved for those already bald or for persons without significant androgenetic hair loss who want to improve upon their natural attributes.Although hair loss in women is generally a far more significant cosmetic problem than in men, a much smaller proportion of women are surgical candidates, since they generally exhibit a diffuse type of hair loss. When medications are developed that are useful in women, an entire new population of patients may benefit from surgery. The increase in female patients might then more than offset any decrease in the number of procedures performed in men. Cloning is another technology that has made significant progress in recent years and may supply the surgeon with an unlimited source of donor hair. Genetic engineering, on the other hand, is a technology still in its infancy, but that may someday render the hair transplant surgeon’s role obsolete. The move towards smaller grafts in the 90’s has produced a number of controversies that are receiving a great deal of attention in the hair transplant community. Among the most hotly debated are 1) the “supremacy” of the follicular unit over traditional mini-micrografting, 2) the practicality of microscopic dissection, 3) the importance of single strip harvesting, and 4) the “ideal” transplant density. As this decade draws to a close, however, no issue is possibly more critical to the future direction of surgical hair restoration as the debate over economy vs. quality.The newer hair transplant techniques have enabled the surgeon to produce unprecedented naturalness, the ability to complete the process in a smaller number of sessions, and the means to accomplish this with a more limited amount of donor tissue. However, these newer procedures are technically more difficult, require a significant number of well-trained staff, are more costly to deliver, and are too impractical for some cosmetic surgeons to perform. These limitations have stimulated a number of enterprising physicians to try to facilitate the more tedious aspects of the procedure with the use of automated devices.Although much of the new technology has served to speed up the procedure, some mechanized devices accomplish this at the expense of quality and the preservation of donor tissue. To what degree this occurs, and what its clinical significance may be, still needs to be assessed in well-controlled, scientific studies. Until then, the subjective value that surgeons and their patients place upon each of these aspects of the transplant may ultimately define the type of procedures offered over the next few years.

I was fortunate to catch an early glimpse of the provocative article “Blind Graft Production with Cutting Grates and Multi-bladed Knives” on its way to Dr. Shiell and the Forum. The gauntlet having been tossed, let me be the first to enter the fray. The question at hand is relatively straight forward. When compared to the highly controlled stereo-microscopic dissection of donor tissue harvested as a single strip, do the potential benefits of blind graft production (which use a multi-bladed knife and a cutting grate) more than outweigh their disadvantages and possible risks? In order to make sense out of the long list of categories used to evaluate the two techniques, I have taken the liberty to organized them into the following groups:1. Intrinsic Factors – Factors affecting the surgical outcome that are intrinsic to the techniques discussed and cannot be eliminated. 2. Extrinsic Factors – Factors that may affect the hair restoration surgery, but ones that can be reasonably modified so as not to significantly impact the outcome.3. Economic Factors – Strictly economic issues that have no effect on quality. 1. Intrinsic FactorsDamage to the follicle Disruption of the follicular unit Viable hair(s) obtained per graftAmount of non-hair bearing tissue transplanted Total recipient wounding Foreign body reactionPseudo-cyst formation Quality control Patient variability Preserving donor supply2. Extrinsic FactorsTime grafts are out-of-body Risk of desiccation Staff training Staff stress and fatigue 3. Economic FactorsCost of equipment Cost of labor Cost to doctor Cost to patient What The Patient Should DoIf I were advising a patient that had to choose between the two hair transplant procedures I would suggest the following:FIRST: To each of the factors assign a GOOD rating where the technique can clearly or potentially be of benefit, a BAD rating if it may do harm, and disregard those issues that make no difference. (For simplicity, I have assigned each factor a value of 1, although some factors are clearly more important than others.) Then count them all, subtracting the bad from the good. SECOND: Pick a top-notch surgical hair restoration team that could control the extrinsic factors so that they would have little or no impact upon the surgery.THIRD: Make a decision taking into account that:- This surgery is being performed on your own body.- You only have a limited donor supply of hair.- You will have to live with the results of the hair transplant procedure (good or bad), for the rest of your life. Microscopic Dissection            Blind Graft ProductionMedical Issues- Damage to the follicle                GOOD                 BAD- Disruption of the follicular unit           GOOD                 BAD – Viable hair obtained per graft              GOOD                 BAD – Non-hair bearing tissue used                GOOD                 BAD – Total recipient wounding                    GOOD                 BAD – Foreign body reaction                       GOOD                 BAD – Pseudo-cyst formation               GOOD                 BAD – Ability to control quality                  GOOD                 BAD – Impact of patient variability               GOOD                 BAD – Preserving donor supply                     GOOD                 BADEconomic Factors- Cost to Patient                             BAD                  GOODTOTAL (good – bad)                    9                                – 9The IssuesI have eliminated the first three economic factors; Cost of equipment, Cost of labor, and Cost to doctor, since the only factor that really matters to the patient is his cost. All the other economic issues are reflected in this one and are not the patient’s problem.Extrinsic factors, if not controlled, can play a major role in the outcome of the surgery. Finding a surgical hair restoration team that is properly trained and experienced can minimize these issues. For example, the time that grafts are out of the body can be reduced by utilizing a sufficiently large staff or by taking a donor strip out in sections. Adverse effects can be further minimized or eliminated by proper graft refrigeration. Any risk of desiccation can be easily eliminated by the use of holding solutions and the proper handling of grafts just prior to insertion. In addition, automation may soon make both of these issues moot. A sufficiently large staff that is adequately rotated and working in a comfortable environment will greatly reduce stress. If the patient is diligent in his research, he can pick a surgical team that satisfies these requirements.The intrinsic factors are the real issue. A 35% incidence in follicular transection that was observed without even using a microscope is, in my opinion, an extraordinary price to pay for a cheaper, faster procedure. It is argued that follicular transection is overestimated when two fragments representing the same follicle are both counted, (this error was not made in these counts) but even if the transection was half that, it would be too much. From my personal experience with a multi-bladed knife with a inter-blade spacing of 3mm, the transection rate was about 20%, and occasionally as high as 35%, so it doesn’t surprise me that transection with blades set at 1mm would easily cause damage in the range of 35% (or even more). In fact, Dr. Rassman, in his own practice, had abandoned using the multi-bladed knife after he had observed the transection rate to be unacceptably high. The fixed blade spacing of the cutting grate used in the next step, would further compound this damage.Much has been made of Dr. Kim’s studies showing that, under controlled conditions, a portion of transected follicles will grow. What is not often mentioned by those quoting his data, is that the hair that is produced is often finer and more delicate than the undamaged, full thickness terminal hair of intact follicles. Unfortunately for the patient, hair shaft diameter is as important to the final cosmetic outcome of the hair transplant as the absolute number of transplanted hairs. Another important issue is the fact that multiple blades break up the naturally occurring follicular units. One doesn’t have to do a controlled experiment to understand that a single pass of the multi-bladed knife with blades set 1mm apart will literally decimate follicular units randomly spaced at a density of 1unit/mm2. Again, the fixed spacing of the cutting crate would further divide any follicular units that hadn’t already been broken up with the multi-bladed knife. Transplanting the whole follicular unit will insure that the greatest cosmetic benefit is obtained from each session. The compact nature of intact follicular units allows them to be placed into very small sites, minimizing recipient wounding. This, in turn, maximizes the amount of hair that can be placed into the cosmetically important areas, while maintaining a totally natural look. Minimal wounding will cause less compromise to the blood supply and produce less scarring. It will enable larger procedures to be performed at one time, and will help preserve the integrity of the recipient bed for future procedures. How much the wounding may be decreased will depend upon the surgical team, but since carefully dissected follicular units contain only about half the volume of the original donor tissue, the total wounding can potentially be cut in half. The fact that transected follicles may grow under experimental conditions should be of little consolation to the patient who wants to get the maximum benefit from his or her hair transplant procedure. Some hair restoration doctors seem to be flippant about generating hair fragments and consider only whether they will or will not grow. In fact, hair fragments are composed of keratin which can be quite inflammatory and the reaction they incite in the dermis can destroy adjacent follicles. Small hair fragments that do grow may not find their way to the skin surface and can result in pseudo-cyst formation, a locally destructive process. We have all seen this in our practices, and from my experience the incidence is significantly reduced when follicular units are transplanted intact. Bilateral controlled studies would, of course, be helpful to document this for the skeptics. The ability to control quality is another important issue. It has been argued that quality control is difficult in follicular unit transplantation. That may be true, but to ignore quality all together is certainly not the solution. A team experienced in follicular dissection can consistently generate the highest quality grafts if one puts forth the effort for proper training and continued monitoring. The problem with both multi-bladed knives and cutting grates is that the slightest deviation in alignment can increase the transection significantly and, unlike microscopic dissection which deals with one follicle at a time, there is no way to make fine adjustments along the way. A final issue is the intrinsic variability of the human scalp from patient to patient, and from one region of the scalp to another. The dissecting microscope is an exquisite instrument for adjusting to this variability. The fixed relationship of the cutting surfaces of the multi-bladed knife and the microtome cannot. Will the doctor performing blind dissection be able to adequately account for this variability in the average patient and will he risk operating on an unwary patient in whom these differences might be profound?In PerspectiveFor those of us who embraced follicular unit transplantation at the outset, it could be argued that we might have acted too hasty. . .  before all the evidence was in. But our rationale was that the procedure would improve the quality of our hair transplant. Our critic’s main objection was that it might not be worth the extra effort. If we had been wrong, there was little to lose except time, effort, and unnecessary expense. In this case, when one risks damaging the patient’s donor supply, the patients have much to lose.The sudden disregard for follicular anatomy exhibited by this “blind grafting technique” runs contrary to much of the progress that has been made in hair restoration surgery over the past 10 years. Hopefully, well-controlled studies will precede the general use of these instruments, so that the extent of damage can be accurately measured. The “blind grafters” should clearly explain all the pros and cons of this type of dissection to their patients, as well as the limited knowledge we have of this technique so far, in order that their patients have true “informed” consent. Let’s not go back to the days of the old plugs when doctors rarely told their patients all of the short and long-term consequences of their procedures.Blind graft dissection may indeed have some economic value, but what is the real cost to our patients?

The past few decades have witnessed major changes in hair transplantation, most notably the trend towards the use of large numbers of very small grafts and the emergence of follicular unit transplantation as possibly the new “gold standard.” In addition to improved surgical techniques, new developments in medical treatments, marketing on the part of physicians, and coverage by the media, have produced an increased public awareness of this rapidly evolving field.The long-term observations of patients treated with the older hair transplant techniques and the use of new objective means to measure donor supply, have made the modern hair restoration surgeon more keenly aware of the importance of maximizing the patient’s finite donor reserves. As a consequence, new ways of harvesting and dissecting donor tissue have been developed to better preserve this supply, and new ways of handling and storing grafts awaiting placement have been devised to enhance the viability of the grafts. In addition, long-term planning has assumed greater prominence in surgical decisions. It is somewhat ironic that after four decades of wrestling with supply/demand issues, new medications for hair loss may soon necessitate a complete re-thinking of the way we plan our procedures.The use of large number of very small grafts has made the transplant process much more laborious and this has prompted the development of new technologies to automate various aspects of the transplant process. Long transplant sessions requiring greater numbers of staff and involving the movement of large numbers of small, fragile grafts has also made quality control a central issue.The decade has seen a dramatic decline in the popularity of scalp reductions and flaps, and fortunately the “pluggy look” that was once the hallmark of many older transplant procedures is now deemed to be unacceptable. Unfortunately, many patients still carry the telltale cosmetic deformities caused by the older techniques and “repair work” has become an increasingly larger part of many physicians’ practices.The initial excitement over laser assisted hair transplants appears to have subsided, because the very tiny sites needed in the newer procedures seems to be best made by cold steel incisions. However, laser technology is rapidly changing and this tool may still have a future role in hair transplantation, possibly in ways we have not yet considered.The development of 5-alpha reductase inhibitors and other medications that specifically attack the biochemical pathways involved in androgenetic alopecia will have a profound influence on the future of hair restoration surgery. Once drugs are able to successfully limit the extent of balding, supply/demand ratios will change, long-term planning may become less important and the aesthetic demands of all patients may substantially increase. As medications become more effective, their long-term safety profile established, and their use more widespread, it is possible that baldness may be preventable. When this happens, surgery may be reserved for those already bald or for persons without significant androgenetic hair loss who want to improve upon their natural attributes.Although hair loss in women is generally a far more significant cosmetic problem than in men, a much smaller proportion of women are surgical candidates, since they generally exhibit a diffuse type of hair loss. When medications are developed that are useful in women, an entire new population of patients may benefit from surgery. The increase in female patients might then more than offset any decrease in the number of procedures performed in men. Cloning is another technology that has made significant progress in recent years and may supply the surgeon with an unlimited source of donor hair. Genetic engineering, on the other hand, is a technology still in its infancy, but that may someday render the hair transplant surgeon’s role obsolete. The move towards smaller grafts in the 90’s has produced a number of controversies that are receiving a great deal of attention in the hair transplant community. Among the most hotly debated are 1) the “supremacy” of the follicular unit over traditional mini-micrografting, 2) the practicality of microscopic dissection, 3) the importance of single strip harvesting, and 4) the “ideal” transplant density. As this decade draws to a close, however, no issue is possibly more critical to the future direction of surgical hair restoration as the debate over economy vs. quality.The newer hair transplant techniques have enabled the surgeon to produce unprecedented naturalness, the ability to complete the process in a smaller number of sessions, and the means to accomplish this with a more limited amount of donor tissue. However, these newer procedures are technically more difficult, require a significant number of well-trained staff, are more costly to deliver, and are too impractical for some cosmetic surgeons to perform. These limitations have stimulated a number of enterprising physicians to try to facilitate the more tedious aspects of the procedure with the use of automated devices.Although much of the new technology has served to speed up the procedure, some mechanized devices accomplish this at the expense of quality and the preservation of donor tissue. To what degree this occurs, and what its clinical significance may be, still needs to be assessed in well-controlled, scientific studies. Until then, the subjective value that surgeons and their patients place upon each of these aspects of the transplant may ultimately define the type of procedures offered over the next few years.

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Dr. Jim Arnold should be congratulated on another excellent and detailed reporting of the ISHRS meeting. We appreciate the inordinate amount of time and effort that he has spent in recording the vast amounts of information that speed by us so quickly. It is amazing how he does it! In reading the article in the Nov.-Dec. 1997 Forum, Vol. 7, No. 6, p. 5, I noticed three small errors in the text that should be corrected. I thought that I might also take the opportunity to briefly discuss them.The text reads “Some patients may average 1or 2 hairs per unit, while others 4 to 5.” While we do see patients with very low density, or Asians, who average 1 or 2 hairs per unit, I have not seen patients who average 4-5 hairs per unit. Patients with high density can have a significant number of 4, or rarely 5 hair follicular units, but this is not their average. The graph that I presented in Barcelona, illustrating this point is shown here. Another important point is that the density (spacing) of naturally occurring follicular units is relatively constant at about 1 group/mm2 in the posterior scalp of most Caucasians, but is less in the Black races (where it averages approximately 0.6/mm2). The text also reads “Dr. Limmer finds the average number 2.3 hairs per unit, while Dr. Bernstein feels the number is closer to 3.” This is also incorrect. As I stated in my presentation, the majority of patients that we see in consultation that are surgical candidates range from 1.5 hairs/unit to 3.0 hairs/unit with an average of 2.0 hairs /unit (rather than 3). The population that actually go on to have surgery have slightly higher groupings at approximately 2.1/hairs per follicular unit. (The graph also illustrates this point). The numbers that I presented were based upon densitometry readings at the time of the consultation, taken approximately 5 cm to the left or right of the occipital protuberance. Only full-thickness terminal hairs were counted. Dr. Limmer and I spoke regarding the slight differences that we each observed and we felt that different patient populations might be a factor contributing to this small difference. The location on the scalp where the measurements were taken will also influence the results, as the follicular unit density is generally highest in the midline of the donor area and decreases laterally. Having prior knowledge of the approximate proportion of each of the different size follicular units that will be obtained in the dissection is extremely important in planning the transplant, since the larger units can be concentrated in select areas to create the appearance of greater central density without having to increase the “closeness” of the sites. These numbers are also important because the pre-operative measurement of density and the estimation of follicular unit size are two means of assessing the accuracy of the follicular unit dissection. The other statement “Hair diameter plays a significant role, as diameter may range by a factor of 5X among patients.” is also incorrect. The word “diameter” should be replaced with the words “Cross Sectional Area.” The range in terminal hair shaft diameter is approximately 2.3 fold (0.06 mm for very fine hair and 0.14 mm for the coarse hair that we often see in Asians). This represents a variation in x-sectional area of approximately 5.4 fold, since area = ~r2 or ~(1/2d)2. It is interesting to note that compared to hair density, hair shaft diameter plays a much more significant role in the volume or “bulk” of the transplant. The range in hair density in patients that we generally transplant is from 150 hairs/cm2 in those of low density, to around 300 hairs/cm2 for those with the highest. In our practice, we rarely transplant patients who present with a density of less than 150/hairs cm2 (except for Blacks and Asians) and uncommonly see patients with a density greater than 300 hairs/cm2. The range is thus a 2-fold difference. If we compare this to the 5.4 fold range in hair cross-sectional area, we see that, in theory, variations in hair diameter should have 2.7 times the cosmetic impact of variations in hair density. In reality, these variables are not totally independent. For example, the widest hair shaft diameters are not generally seen in the same patients who have the highest hair densities. Nevertheless, one can make a strong argument for the quantitative assessment of hair shaft diameter, as well as density, in the pre-operative evaluation of patients considering hair transplantation.

There has been a recent surge of interest in “laser hair transplantation” that has paralleled the increased use of lasers for a wide variety of cosmetic surgical procedures. Lasers generate great enthusiasm on the part of both physician and patient, but this has sometimes exceeded the actual value of the laser as a surgical tool. An obvious example has been the use of the CO2 laser as a nonselective, destructive modality to remove tattoos which left scarring and a cosmetic deformity worse than the tattoo itself. This has been subsequently replaced by pulsed lasers with specific pigment absorption (such as the Nd:YAG, Ruby, and Alexandrite lasers) operating on the principle of selective photothermolysis that truly offers benefit in the treatment of these lesions. Super- and ultra-pulsed CO2 lasers are now being used to replace “cold steel” in generating hair transplant sites. However, before we rush to use lasers in hair restoration surgery, we should first apply logic and reason to this application, and then proceed cautiously with carefully controlled studies so our patients will only benefit from its use. The following discussion will address various aspects of current laser technology in the specific context of the most recent advances in hair transplantation techniques. The intent will be to challenge the theoretical basis for the use of existing lasers, to question some dubious claims regarding their benefits, and to suggest future areas of laser research. WHAT IS A LASER HAIR TRANSPLANT? First, it is important to clarify what is meant by “laser hair transplantation.” The present role of lasers is to solely create the holes or slits (recipient sites) for the grafts to be inserted into. To consider this a “laser transplant” is to ignore the myriad of other factors that contribute to making the procedure successful. Until lasers are involved in other major components of the transplant, such as harvesting, graft dissection, or placing, “laser hair transplantation” should be replaced with a term such as “laser site creation” to more accurately reflect its current role in the procedure. A PAINLESS PROCEDURE?The claim that laser transplantation is a painless process is misleading. The lasers currently being used are “ultra – or super – pulsed” CO2 lasers. Unlike lasers that operate by selective photothermolysis, these lasers create a hole by simply vaporizing tissue. Because the pulse (span of time the beam is on at any given moment) of these new lasers is extremely short, there is not much heat transfer or injury to “surrounding tissues.” Nevertheless, the tissue which the laser acts upon is nonselectively destroyed. Because of this, the laser is extremely painful unless local anesthesia is administered to completely numb the area prior to its use. Thus, it is not the laser that is painless. The pain-free environment is set up by the preoperative anesthesia used in all transplant procedures. BLOODLESS SURGERY The next claim, that the laser procedure is relatively bloodless, minimizes the most important physiological consideration determining the success of the transplant, namely oxygenation. The hair transplantation process should be aimed at maximizing blood flow to the implanted hair follicles, rather than reducing it, and any manipulation that compromises proper oxygenation will potentially compromise graft survival. Preliminary results suggest that when the laser sites are compared to sites made with conventional surgery, “a few patients have shown less hair yield in some of the laser grafts [1].” Dr. Unger points out that when making conventional slit sizes with the laser, “we are close to an unacceptable width of thermal damage.” The experience of Khan is similar, and he expresses special concerns of decreased growth when the distance between laser sites is 1 mm or less [2]. When using extensive micrografting techniques, the spaces between grafts are often in this range, and the cumulative thermal damage produced in large sessions may prove disastrous. It is, therefore, extremely important to objectively measure the impact of the coagulating effects of the laser on blood supply and graft survival in the setting of extensive micrografting, since this does appear to be the trend of the future [3]. As with electrosurgery, the laser specifications can be modified so that there is relatively more cutting than coagulation. It seems reasonable that work be focused in this direction, as this will decrease thermal injury while, at the same time, taking advantage of the laser?s ability to make rapid, uniform sites. PROBLEMS WITH HEMOSTASISThe coagulating effect of the CO2 laser may enhance visibility during the procedure, but the application of bi-manual traction on the skin and the judicious use of epinephrine can also provide hemostasis and allow for adequate visibility during both site creation and the placing of grafts without compromising the blood supply. Cold steel techniques that produced defects in the recipient area in the form of slits, 2-6 mm in length, or punches 1.5-5 mm in diameter, significantly compromise blood flow to the recipient site and reduce graft survival when the transplants are made too close. The laser has the added detrimental effect of sealing off the microvasculature. The poor growth with older techniques taught us the vital importance of preserving the vascularity in the recipient area, and this lesson should not be wasted when trying to increase operative visibility with the laser, especially when this can be accomplished by simpler means. INTEGRETY OF THE CONNECTIVE TISSUE Another problem created by the laser is the destruction of dermal collagen and elastic fibers. This effect on recipient tissues causes a decrease in normal skin elasticity and, as a result, grafts have an increased tendency to fall out from laser-made sites. Certainly, one would have to question if the grafts that remain are secure enough to ensure optimal growth. Work by Beeson has shown laser sites to have more necrosis and scarring 3 days after surgery and more fibrosis at 2 months than with the sites made with steel [3]. The elasticity of normal skin allows the recipient site to grasp the small follicular implants and secure them in place. This assures for the close proximity of the sides of the implant to the dermis in the recipient site, which serves to minimize microscopic dead space and hematoma formation, and facilitate healing. In a new method of hair restoration surgery recently described in the International Journal of Hair Restoration Surgery [4], where the actual follicular units are used as the implant, recipient wounds as small as 1.0 to 1.3 mm in length can accommodate as many as four hairs. This is accomplished by taking advantage of the anatomic proximity of hair within each naturally occurring group and discarding the intervening skin in the dissection. In this situation, the preservation of recipient dermal elasticity is evidenced by the fact that patients undergoing follicular transplant procedures are able to shower and gently rinse the transplanted area the day after surgery without the risk of losing their grafts. In addition, the rapid healing allows oozing and crust formation to subside over this same 24-hour period. When healing is complete, there is no clinical evidence of scarring, even when the scalp is shaved. LASERS: NEW TECHNOLOGY FOR AN OUTDATED TECHNIQUEThe major advantage that lasers are claimed to have over traditional slit and punch grafting is that they can create a slit (which purportedly looks more natural than a hole created by a punch), while, at the same time, removing tissue like a punch to make more room for the implant, in effect, having the best of both worlds. In the older techniques, where the grafts were not “anatomic” and contained hair that reached across multiple follicular units, the recipient site needed to accommodate it was unduly large, causing poor healing, as well as graft compression. In follicular transplantation, neither large slits nor punches are required to accept the donor grafts. By identifying the patient?s natural hair groupings, the implants can be pre-trimmed of the excess tissue between the groups, resulting in tiny follicular units that can be placed in very small sites, solving the problems of both recipient bulkiness and compression. Therefore, the claim that lasers have the advantage of removing recipient tissue while creating a slit has no relevance in follicular transplantation. THE DIRECTION FOR LASER RESEARCHFuture laser research should be directed toward a technology that could “read” the follicular groups “in situ.” In the donor area, the laser would dissect away the tissue between follicular units having the effect of decreasing the transplanted volume of skin, while maximizing the transplanted quantity of hair; producing an implant containing hair groups matching those found in nature. In the recipient area, current laser use is limited to areas relatively devoid of hair, as the beam would obviously damage any adjacent follicles. It is also limited in its ability to re-treat an area already transplanted, unless significant spacing were left between the previous grafts. In contrast, hand-made sites using a very small steel instrument can easily avoid existing hair or grafts, and if a follicle was “hit,” it would most likely survive the trauma or regenerate from its growth center. Much of current laser research has been directed to the production of a laser scanner that has the ability to rapidly produce uniform sites in either a grid-like pattern or random distribution without regard to the location of existing hair [5]. In order to be of general value, the laser must be able to identify the existing hair and make sites only in the intervening spaces, requiring a level of technology not presently available. Another challenge of the laser scanner would be to compensate for variability in laser effects brought on by the inherent curvature of the skull. Not only will the changing contour serve to amplify or defocus the beam by altering the effective operating distance, it will also change the incident angle of the light source and, ultimately, the direction of the hair. These adjustments are now performed manually, but are, nevertheless, critical to a successful cosmetic outcome. There is also significant variability in the thickness of the scalp from one patient to another and in different regions of the scalp. The laser must be able to at least match the sensitivity of the human transplanter who can “feel” these differences and can limit the depth, sparing injury to the larger blood vessels and nerves. In order to have a more natural appearance, modern lasers should generate sites only in a random pattern rather than according to an organized template. Finally, artistic nuances used in creating a delicate hairline, a widow?s peak, the swirl of the crown, or in rebuilding the temples (with its abrupt directional changes) would be difficult to program into the laser and might still have to be accomplished manually. A look at current research in hair transplantation worldwide suggests that in the near future, significant advances in hair restoration surgery may lie in automating the manual process, rather than in laser surgery per se. Mechanical instrumentation currently being developed will streamline the entire procedure, from the harvesting of the donor strip to the creation of sites with the simultaneous insertion of the implants. The role lasers will play in this overall process is still unclear. CONCLUSIONSAs laser technology improves, laser sites become smaller, and the problem of thermal damage is adequately addressed, the advantage of rapidly producing large numbers of uniform sites will make the laser a more valuable tool. When the laser, directed at the donor area, can cut skin by “reading” the spaces between the natural hair units with minimal thermal injury, it will significantly alter the transplant process and create a more compelling argument for its use. And until the laser scanner can be designed to avoid existing hair, this instrument will not be truly versatile. Hopefully, this level of sophistication is not “light years” away. Until then, let us be cautious and allow time for science to catch up with our enthusiasm. Only when the power of the laser has been applied successfully to all of the critical elements of the procedure may we rightfully use the term “laser hair transplantation.”REFERENCES1. Unger WP. More on laser use. Hair Transplant Forum Int 1995; 6:15-16.2. Arnold JE. Report on ASHRS Orlando meeting. Hair Transplant Forum Int 1995; 6:4-5.3. Rassman WR, Carson S. Micrografting in extensive quantities. Dermatologic Surgery 1995; 21:306-311. 4. Bernstein RM, Rassman WR, Szaniawski W, Halperin AJ. Follicular transplantation. Int J Aesthetic Restorative Surg 1995; 3:119-132. 5. Unger WP. Laser Hair Transplanting. Int J Aesthetic Restorative Surg 1995; 3:137-142.

Regarding the ability to perform hair transplants using grafts in extensive quantities, many “unanswered questions” already have answers. The first issue that “the emphasis in hair restoration has somehow shifted from the eventual outcome or product to the speed and magnitude of the process” is not correct. The outcome is, and always should be, the emphasis in any hair restoration or replacement process. The speed and the magnitude of the process, however, directly affect this outcome. There are a number of reasons; a critical element affecting the final result of the hair transplant is the motivation of the patient to reach a point where the hair restoration is cosmetically useful. Multiple partial procedures produce short term cosmetic problems, unnecessarily extend the duration of the surgical process, interfere with the patient’s daily life, and often leave the patient frustrated and unsatisfied. These patients can be so frustrated that they give up on the process entirely. The ability to perform the restoration in one or two procedures encourages a much greater proportion of patients to complete the process. Large hair transplant sessions solve other problems intrinsic to multiple small procedures. The first concerns the donor reservoir. Each time grafts are harvested from the donor area there is loss of potential donor hair due to destruction of hair adjacent to the wound edges as a result of the fibrosis associated with primary intention closures. In addition, the hair follicles adjacent to the healed suture line are often distorted and more difficult to harvest on subsequent hair transplant procedures. Minimizing the number of times the donor area is accessed, will minimize the resulting loss and distortion due to the closure. In the recipient area, the problem with fibrosis also favors fewer hair transplant procedures. In a “virgin scalp”, the blood supply travels unimpeded to the entire recipient area. However, when multiple sessions of large grafts are used, each graft placed in the recipient site induces local scarring that interferes with subsequent blood flow and has the potential to transect or seal off viable blood vessels, even if this effect is subtle. In subsequent procedures, the hair placed between existing grafts is implanted into this scarred tissue and potentially receives diminished blood flow. In hair restoration using dense packing, the donor site is created with an instrument thinner, and one that produces less trauma, than a traditional punch instrument. A blood vessel that might be pierced would immediately reseal analogous to the way a vessel heals after venipuncture. When the slender graft is then placed into the site, the graft would cause no additional trauma to the vessel. If it were true that “the diminished blood supply fails to support uniform graft take and consequently hair growth” then asymmetry, gaps or areas of variable density, would result from the dense packing technique and this is not observed, in spite of the fact that the dense packing is used predominantly in the frontal hairline, where any problem would be most obvious. The second issue, that “megasessions cannot duplicate the density of the traditional approach” is really not an issue at all. The density of the traditional approach to hair restoration is NOT one that we should aspire to. The problem with larger grafts in the hair transplant (and I include mini-grafts in this category) is that they don’t parallel the way hair grows in nature. Due to graft contraction they have a higher than normal density with greater than normal spacing in between. In nature, hairs in the frontal hairline (approx. the first 1/2 cm.) grow as single units and behind this region, the natural hair groupings contain two or three hairs. Large grafts contain too many hairs and produce an uneven density that doesn’t mimic nature. This is the cause of the most common complaint that patients have about their hair restoration procedure i.e. that it looks like a hair transplant and doesn’t look natural.The third issue, that “very small grafts, although natural, cannot be placed close enough together without injury to simulate the density of the larger grafts” has already been answered. The goal in a hair transplant should not be to simulate the density of the grafts, but that of nature. The obsession with density misses the direction we should be headed. The goal of all hair restoration surgery is to produce a fullness that will look natural as the individual ages. An attempt to match or exceed ones original density, even if only at the frontal hairline, will not only be cosmetically unacceptable in the long term, but will tax the donor bank and limit the ability for future hair transplant procedures to be able to cover additional areas as the balding progresses. In judicious planning, the grafts in the frontal hairline should contain only single hairs and be placed close enough to block the eye from looking into the scalp, but not so dense as to be unbalanced as the patient continues to bald. Finally, the statement “large sessions force distribution of the transplanted hair over the entire extent of the balding scalp” is incorrect. The transplant surgeon using extensive grafting of small follicular units has the total freedom to place these grafts in any distribution that he chooses and, if the hair restoration is planned appropriately, would be most dense in the “crucial frontal zone” that you describe. I agree that the vertex should always be left open in a young extensively balding individual with an average or below average donor density. When the patient has had permanently transplanted hair covering the front and top of his scalp, and the fullness is to his satisfaction, and he still has some reserve of donor hair to address further diminution of the donor fringe, then the crown can be addressed. And this would best be accomplished by extending the hair transplant further back, rather than treating the crown as an isolated area. Continued experience with the megasession will show that it increases the power and flexibility of the hair transplant procedure rather than limiting it. Future work should be directed at exploring the various ways this safe, but technically demanding, procedure can be of benefit to the balding patient.