The Future in Instrumentation

James Arnold, MD

The imaginative minds of many surgeons have given us a glimpse of future developments in hair transplantation techniques and instrumentation. Efforts to simplify the work or to combine tedious steps include devices to automatically insert grafts, to cut donor tissue into multiple grafts in a single pass, and to lessen crush damage to grafts are surfacing.

The recipient site has recently received a new focus of interest among transplant surgeons reflecting a desire to lessen the traumatic effects, which occur from cutting hundreds of recipient sites in close proximity. New instrumentation has been developed with the intended goals of preserving the blood supply and minimizing scarring to the scalp. The concept of cutting recipient sites to an absolute minimum depth is based on the anatomical design of the vasculature supplying blood to the scalp1.

Montagna2 and others have demonstrated the primary distribution of blood to all areas of the scalp is through a network of arteries that lie beneath the dermis. This arterial system is strictly confined to the fatty, sub-dermal compartment with even the smallest arteriole rarely entering the dermal portion of the scalp. Small ascending vessels bring blood to the dermis, which is then distributed, through a vast network of capillaries, supplying the appendages of the dermis including the follicles. For the transplant surgeon, it is important to recognize that the basic arterial system lies totally beneath the dermis, while the dermis proper is supplied with capillaries alone. The importance of this information is related to the ability of the scalp to readily heal damaged capillaries. In contrast, the healing mechanisms for the underlying arterial network are more limited.

Capillaries have an outer wall of only a single cell in thickness and are replaced quickly if severed or damaged, via the process known as angiogenesis. Vessels of the arterial system, even the smallest arteriole, are compound structures with an endothelium lining, a muscular wall and an outer sheath. Re-canalization of arteries may occur, and existing anastomosis may expand, but neither response will be as efficient for providing blood to the scalp as the original arterial system. The concept of minimal depth recipient sites, therefore, is to limit cutting of the sites to the capillary dermis and avoid penetrating into the sub-dermal region where permanent compromise to blood supply may occur. In general, the capillary dermis is thick enough to allow recipient sites 3-4mm in depth without penetration into the sub-dermal compartment. Recipient sites 3-4mm deep are generally adequate in depth for transplant grafts.

There are several challenges for the surgeon in cutting minimal depth recipient sites. First, the depth of each site should extend the full 3-4mm, no less and no more. Second, the sites should be fully open at the base of the site to adequately accommodate the base of the graft.

In the past, lancet or spear-point shaped blades were popular among transplant surgeons for cutting recipient sites. Lancet blades, such as hypodermic needles, No-Kor needles, #11 scalpel blades, and spear point blades have a sharp point which facilitates penetration of the scalp. However, to open the deeper portion of the recipient site, lancet and spear-point blades must extend beyond the 3-4mm minimum, usually penetrating well into the territory of arterioles. A better design is a chisel-shaped blade, as the blade will cut an opening of uniform width along the entire length of the incision. In order for the flat, chisel-shaped blade to penetrate the scalp as easily as a pointed blade, the chisel must be extremely sharp. To control depth, limiting penetration 3 to 4mm, a "stop" can be used.

An instrument designed specifically for cutting minimal depth recipient site is the Min-de Knife TM (A to Z Surgical, Inc. San Jose, California). The instrument has a chisel blade sufficiently sharp to penetrate the scalp easily and the blade handle acts as a stop to control cutting depth to either 3mm, 3.25mm, 3.5mm or 4mm. Surgeons familiar with the instrument describe less bleeding occurring in the recipient area. As evidence of this, minimal depth incisions ooze from the dermal capillaries, but active bleeding from punctured arteries occurs less frequently than with lancet or spear-shape blades.

There is no doubt that many improvements will continue to evolve in the field of hair transplantation. While the basic techniques will remain the same, new methods and instruments will greatly simplify the process.

REFERENCES

Arnold, J.: What’s new in techniques and instrumentation? American Academy of Dermatology Annual Meeting, February 27-March 4, 1998, Orlando, Florida. (AAD Audiotape 320A and B)
Montagna, W. Parakkal PF: The Structures and Function of the Skin. New York cademy Press 1956

Automated Graft Cutting

E. Antonio Mangubat, MD

The future of hair restoration surgery (HRS) lies in technology and automation. Contemporary HRS differs from most other cosmetic procedures in its high demand of skilled manpower, great dependence on non-physician assistants and prolonged procedure times. Our noted colleagues, including Marritt, Limmer, Seager, Bernstein, Rassman and others, have taught us the value of large numbers of small grafts in producing natural results. Rassman and Bernstein go on to advocate the exclusive use of follicular units in HRS.1

Although the HRS community universally recognizes the value of small grafts, there is still much controversy as to which methods yield the best results. Furthermore, managed care pressures have caused the influx of new HR surgeons creating intense market competition never before seen in HRS history. These forces have influenced the HRS community to become faster, more efficient yet strive for the best results.

The nature of contemporary HRS is repetitive tasks: 1) graft cutting and 2) graft placement. With the exception of a few individual patient variations, these tasks are virtually identical for all patients undergoing HRS. Repetitive tasks naturally lend themselves to automation. The focus of this section is the automation of graft cutting. The ideal graft cutter would produce large numbers of hair grafts with uniform size and shape and without follicular damage. The grafts would all be viable, easier to place and procedure times would be significantly reduced.

The use of impulsive force to significantly improve the quality of grafts processed with an automated graft cutter has been recently introduced into hair transplantation.2 Impulsive force is a physical concept defined by the equation:

Where ðDt is the duration of time during which the external force is applied.3 A cursory examination of the equation demonstrates that the smaller ðDt for any given external momentum, the larger the impulsive force. Many common uses of impulsive forces are seen today including splitting wood with an ax, hitting a golf ball and a martial arts expert breaking bricks with a bare hand. The feasibility of these examples could not be explained without this physical concept. The latter example is most striking with a human hand applying a small external force for a very brief period of time producing impulsive forces large enough to break the brick material which is many times harder than human flesh. Prior graft preparation devices do not take advantage of this physical property and thus crush injury to the grafts may occur, especially if the blades have been dulled by prior use.

The impulse graft cutter consists of a stable base and three sets of parallel spacer bars, which hold the cutting blades rigidly in place. A series of long 1.0 mm donor strips are then taken with a multi-bladed knife. Harvesting high quality donor strips with a multibladed knife is greatly technique-dependent4 and is critical to successful graft cutting automation.

After trimming the excess fat and separating the donor strips, a strip is placed on the graft cutter carefully aligning the follicles with the cutting blades. A wooden tongue blade is used as a force spreader to cover the donor strip and hold it firmly in place while a rhinoplasty mallet is used to impart the impulsive force to the donor strip. Impulsive force then causes a clean shearing of the tissue with surprising little transection.

Follicular trauma can take many forms including transection, desiccation5, 6 and prolonged tissue anoxia (time-out-body)7. Although graft cutting automation may potentially increase the risk of transection, it reduces the risks of desiccation and donor anoxia by the significant reduction in procedure times. In addition, automation decreases expenses, dependency on skilled staff, training requirements and ameliorates the disruption of staff turnover. The graft cutter places the responsibility of quality graft production back in the hands of the surgeon.

A major challenge that lies ahead is to make HRS more affordable. The expense of HRS lies in its time consuming nature. Technology will ultimately make HRS more affordable through efficiency, speed and reproducible results. This era in HRS is upon us.

REFERENCES

Bernstein RM, Rassman WR, Szaniawski W, Halperin A: Follicular Transplantation. International Journal Of Aesthetic And Restorative Surgery 1995 3:119-132.
Mangubat EA. Impulsive Force: A New Method To Cut Grafts. International Journal of Cosmetic and Restorative Surgery 1998. 6:19-23.
Halliday D, Resnick R. "Collisions" In Fundamentals Of Physics, P 155-161, John Wiley & Sons, Inc., 1970
Arnold J: Pursuing The Perfect Strip: Harvesting Donor Strips With Minimal Hair Transection. International Journal of Aesthetic and Restorative Surgery 1995. 3:148-153.
Gandelman M: Light and Electron Microscopic Analysis of Injured Grafted Micrografts. Presented at the International Society of Hair Restoration Surgery, November 1997, Barcelona, Spain.
Gandelman M: Light And Electron Microscopic Analysis Of Injured Grafted Micrografts: Stage II. Presented at the International Society of Hair Restoration Surgery, September 1998, Washington, DC.
Limmer BL: Micrograft Survival In Hair Replacement: Surgical And Medical. Pg. 147-149. DB Stough And RS Haber Eds. Mosby. 1996
COMMENTARY

The purpose of this section has been to introduce a new device that may significantly reduce the time and labor involved in graft dissection. In spite of its potential benefits, some of the co-authors have concerns about the automated graft cutting technique for the following reasons:

It is important to stress that the growth rate and clinical significance of transected hair follicles, either produced by the multi-bladed knife during harvesting, or from other aspects of the dissection process, has not been examined in well controlled studies and is, at the present time, highly controversial.
The successful use of the impulsive technique depends upon the generation of very thin strips using the multi-bladed knife. The experience of some of these authors has been that even with 3mm spacing, the multi-bladed knife can cause significant and unacceptable damage to the donor tissue. The very thin, 1 to 2 mm strips needed for this technique would be expected to cause even greater transection.
Dr. Kim reported an increased incidence of pseudocyst formation when transected follicles are implanted, especially the lower portion. At this time the clinical impact of this finding is unclear.
Avoiding follicular injury, especially transection, is in part dependent upon the ability of the relatively rigid follicular structures to be pushed aside during follicular dissection, as the cutting instrument passes through the surrounding dermis and subcutaneous fat. In theory, the rapid impact of the impulsive technique should decrease crush injury to grafts; however, it is also possible that by essentially "freezing" the tissue in place during the rapid impulsive force, follicular transection may actually increase. Well-controlled studies are needed in each of these areas.
Robert M. Bernstein, MD

Automating Graft Placement

With many physicians now converging on a single standard of quality (the follicular unit), 1 the focus of hair transplantation is now moving to solve the problems addressing the cost of the procedure in terms of labor, time and money, and in the consistency and predictability of product. Newer techniques have evolved which move more hair in smaller and smaller units. More labor has been neeeded to deal with the increasing workload that these new techniques require. Labor intensive processes produce human variables, which lie at the heart of the problems defined herein. As the labor-intensive process is solved, costs will fall and quality of product will rise. The new standard of quality will then be in the reach of all physicians performing cosmetic hair restoration surgery.

Most surgical procedures utilize only one or two assistants as the surgeon performs the procedure. In hair restoration, the surgical procedure is largely performed by a large technical staff because it has become tedious, time consuming and monotonous. At times, the procedure becomes unmanageable and, in response to this, the surgeons have abdicated quality control to the technical staff doing the work. Results vary with the expertise of the staff and consistency becomes a hit-or-miss process. If a surgeon is fortunate to have good surgical management skills and a dedicated, loyal and stable staff, results will be more predictable. However, this should not be a precondition for quality surgery.

Automation lies at the heart of the solution for it can address problems of speed and quality, as well as allowing the surgeon to more easily regain control over the surgical process. The automation solution should accomplish the following goals:

Reduce surgical time to under 3 hours for a typical surgery.
Reduce labor to a surgeon and one or two assistants.
Reduce or eliminate many of the human variables associated with the surgical procedure.
Reduce the stress of the procedure on the surgeon and staff.
Reduce the training and skill requirements for the surgical staff.
Reduce graft damage from manipulation and/or drying.
Reduce the need for human quality control processes other than with the surgeons direct involvement.
Make the procedure safer for the patient so that it produces less trauma by reducing (a) medication, (b) anesthesia time, (c) wounding, (d) bleeding and (e) tissue exposure to hostile environmental factors.
To accomplish this, the various process involved in the hair transplantation process must be rethought and reengineered. For simplicity, the process can be divided into two phases: graft harvesting, and graft placement. Automation should be able to simplify the entire process either step-by-step or through some generally integrated solution. The current discussion addresses new instrumentation designed to facilitate the second phase of this process, namely graft placment.

Traditionally, sites (wounds) were created in the recipient area and grafts were placed into the pre-formed sites in a second step. In the traditional manual process, the grafts were handled a number of times, often exposed to drying at points along the way. During the placement phase, as in the dissection phase, graft damage and desiccation had to be minimized. Grafts were often grasped and squeezed repeatedly in the growth regions of the follicles, as staff members tried to implant them into the scalp.

Graft placement is a very delicate process and learning how to manually place the grafts in a competent and efficient manner, with minimal trauma, often requires months or years of experience. Preventing graft drying is equally important and ignoring these two important factors will negatively impact graft growth.

Automation devices available today include the Choi Hair Transplanter2 and the Rapid Fire Hair Implanter Carouseltm3. A third, the Hair Implanter Pen, 4 is not yet commercially available.

Choi Hair Transplanter

The Choi instrument has, until recently, been the only device in use, which makes the recipient sites and places the grafts at the same time. However, it holds only one graft at a time and the loading process is laborious, time consuming and inefficient. It also works best with the more rigid, coarse Asian hair since it pushes (rather than pulls) the hair into the recipient site. Its advantage over the manual technique is that the manual skills for placing grafts is largely eliminated refocusing the technical skills to loading the Choi device by hand. However, for a well-trained technician, it can take longer to load the Choi device than it takes to place grafts by hand. Another advantage is that human variables are reduced during the placement process.

The Rapid Fire Hair Implanter Carouseltm

Like the Choi Device, the Carousel combines what was always a two step process into a one step process but is not limited to holding and delivering just a single graft. The Carousel uses a cartridge to hold 100 grafts in a controlled environment. The Choi Device employs a piston and pushes the grafts into the hole while the Carousel gently pulls the graft into the hole. The author believes that this mechanism is superior to the Choi mechanism as it protects the grafts from compression during the placement process thereby minimizing trauma. It is also more versatile, easily accommodating different shaft diameters. The Carousel should provide the following benefits:

Single Action for Graft Placement: Each recipient site is created and the graft is placed directly into the recipient site with a single mechanical action. In the majority of cases, the grafts will remain in place with no additional manipulation. In certain situations, the grafts may need a fine adjustment to keep them from lifting after insertion.
Less Bleeding: Bleeding is reduced in the majority of sites as immediate graft placement compresses many of the smaller blood vessels in the recipient site. The immediate insertion of the graft creates a tamponading effect on small open blood vessels.
Less Anesthesia Administered: The total anesthesia dosage is reduced commensurate with the shorter surgical time.
Less Graft Manipulation: Manipulation of the grafts during the placement process is virtually eliminated. The compression (squeezing) of the graft with forceps is no longer necessary for the placement process. This reduces the possibility of damage to the graft.
Controlled Graft Storage: There is no significant period in which the grafts are exposed to the atmosphere after they are prepared. A specially designed cartridge, which is the storage element for the grafts, keeps them moist in a saline (or lactated Ringer’s) droplet until they are placed into the recipient area. This process prevents the individual grafts from being touched after they are placed into the cartridge.
Less Emphasis for Quality Control Monitoring during Placing: Quality control emphasis involved with human variables are reduced.
Better Graft Accounting: Graft accounting is simplified because the count can be based on the slots filled within the cartridge and the number of times the device is loaded.
Less Staff Stress: The time consuming and laborious process of placing the grafts into holes or slits is reduced. Staff fatigue and eyestrain are minimized.
Appropriate Physician Focus: By reducing the tediousness of hair transplantation the surgeon is able to focus on the excision of the donor site, the design of the hairline, and the placement of the grafts.
Shorter Staff Training: The protracted training period required to teach graft placement is reduced. However, at least one member of the surgical team must be skilled in manual graft placement techniques in the event grafts are expelled during the placement process, or other situations that may require manual intervention.
Procedure Costs: An expedited surgical procedure frees facility capacity and the physician’s time to a significant degree. Because costs are a critical factor in the decision to elect transplantation as a solution to hair loss, decreased costs should reduce the threshold for the decision ot have surgery.

The Hair Implanter Pen

The Hair Implanter Pen was developed by Dr. Pascal Boudjema, a brilliant inventor in field of hair transplantation (he also invented the Calvitron). The Hair Implanter Pen utilizes a suction tip to grasp the end of a hair graft of any small size. The surgeon drags the graft into a pre-formed wound and then the suction is released along with the graft. As the mechanism does not grasp or squeeze the graft, there should be little or no trauma to the graft. The Hair Implanter Pen can increase the placing speed, thereby reducing the surgical time. This instrument should be commercially available in the near future.

The philosophy that "necessity is the mother of invention" will work to the benefit of both surgeon and patient. Newer automation technologies are inevitable in view of the problems in delivering today’s procedures involving the movement of large numbers of small grafts. We are moving to an integrated, technically based surgical procedure, less dependent upon many supportive staff, and less costly to deliver. Traditional surgeons’ art is the hub of cosmetic surgery and, as these new technologies evolve, the cosmetic surgeon will be allowed to focus upon that art in the same vein as the other traditional surgeries he/she performs regularly.

REFERENCES
Bernstein RM, Rassman WR, Szaniawski W, Halperin A: Follicular Transplantation. International Journal of Aesthetic and Restorative Surgery 1995; 3: 119-132.
Choi YC, Kim JC: Single hair transplantation using Choi hair transplanter. J Dermatol Surg Oncol 1992; 18: 945-948.
Rassman WR, Bernstein RM.: Rapid Fire Hair Implanter Carousel: A new surgical instrument for the automation of hair transplantation. Dermatologic Surgery 1998; 24: 623-627.
Boudjema P: A new hair graft implanter: The hair implanter pen. Hair Transplant Forum Int 1988; 8(4): 1-4.

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