Evolution of instruments for harvest of the skin grafts.

BACKGROUND: The harvest of autologous skin graft is considered to be a fundamental skill of the plastic surgeon. The objective of this article is to provide an interesting account of the development of skin grafting instruments as we use them today in various plastic surgical procedures.
MATERIALS AND METHODS: The authors present the chronological evolution and modifications of the skin grafting knife, including those contributions not often cited in the literature, using articles sourced from MEDLINE, ancient manuscripts, original quotes, techniques and illustrations.
RESULTS: This article traces the evolution of instrumentation for harvest of skin grafts from free hand techniques to precise modern automated methods.
CONCLUSIONS: Although skin grafting is one of the basic techniques used in reconstructive surgery yet harvest of a uniform graft of desired thickness poses a challenge. This article is dedicated to innovators who have devoted their lives and work to the advancement of the field of plastic surgery.

INTRODUCTION

Three basic types of instruments have been designed for removing a graft of split-thickness skin from its donor site: The knife, the drum-type dermatome and the electrical dermatome. The choice of instrument usually depends on the surgeon's past experience; knives are generally more popular with the surgeons of Great Britain and the continent, whereas dermatomes are favored in North America. The principle on which all these instruments are based is that of a sharp blade moving back and forth to cut a piece of skin whose thickness is controlled by a calibrated setting on the instrument or by the surgeon himself.

Brief history of free skin grafting

Skin grafting is a fairly modern addition to surgical therapy. The vast majority of skin grafting has been performed in the last century, although its roots originate in ancient India. Mutilations of the ear, nose and lip were treated as early as 600 BC with the use of free gluteal fat and skin grafts.[1]

Before pedicled-flaps were employed in reconstructing noses, the Tilemaker caste in India are said to have successfully utilized free grafts of skin, including subcutaneous fat taken from the gluteal region, after it had been beaten with wooden slippers until a considerable amount of swelling had taken place. They used a secret cement for the adhesion, to which was ascribed special healing power. This was called the “Ancient Indian Method.” This is the earliest record of free whole-thickness grafting.[2]

Hundreds of years passed and, up to the beginning of the nineteenth century, nothing of importance was performed in regard to the transplantation of free grafts of skin. Then, G. Baronio (1759-1811), a physiologist, carried out the following experiments in 1804. He transferred various thicknesses of skin of various sizes at variable time intervals from side of the root of the tail of a sheep to the opposite side. All the grafts were successful and the grafts bled when cut into 10-12 days after transplantation. Little notice was taken of these very significant experiments.[2]

Attempting to revive the “Ancient Indian Method,” Bunger, of Marburg, in 1823 reported the partly successful transplantation of a free whole-thickness skin graft from the thigh for the repair of a nasal defect, but von Graefe did not succeed with his attempts at rhinoplasty with free grafts. Sir Astley Cooper removed skin from an amputed thumb and used it for stump defect coverage in 1817.[3] Jacques-Louis Reverdin (1842-1929), a Swiss surgeon, reported to the Societe Imperiale de Chirurgie in Paris, on December 8 1869, on the hastening of the healing of granulating wounds by means of small, very thin, detached bits of transplanted skin, which he called “epidermic grafts.”[4] The skin was pinched up with forceps and a small piece, a few millimeters in diameter, was cut off. Many such pieces were cut off and impaled in the granulating bed to be grafted, the principle being that epithelium would grow out from these islands and soon effect a covering of the area. This came to be known as “the pinch graft,” a term not quite correct as the pinching and cutting with scissors is too traumatizing and is no longer used. The “pinch graft” gave epithelization by “secondary intention,” wherein the epithelium spreads out from the individual islands that are grafted.[5] Cosmetically, it is a poor graft, as both the donor area and the graft are unsightly, with numerous humps and hollows [Figure 1].

Figure 1

Reverdin “pinch graft” sissors ‘© British Association of Plastic, Reconstructive and Aesthetic Surgeons’ permission from BAPRAS Anthony Wallace Archive of The Royal College of Surgeons, London

In 1872, Reverdin admitted that his grafts contained a portion of the dermis and, therefore, was not an epidermic graft. L. X. E. L. Ollier (1831-1900), of Lyon, in 1872, successfully transplanted much larger films of skin (4, 6 and 8 cm2) using the entire epidermis and a portion of the dermis. Sir Astley Cooper removed skin from an amputed thumb and used it for stump defect covarage in 1817.[3]

At the Fifteenth Congress of the German Surgical Association, in 1886, Carl Thiersch (1822-1895) presented his perfected method of skin grafting, in which he covered the defects with large films of epidermis with a very thin portion of the dermis, but gave no credit to Oilier who had done the same thing 12 years previously.[3] Over the next few years, the Oilier-Thiersch type of graft became much thicker, so as to include about one-half of the thickness of the dermis, and has been called the “split graft” (Blair and Brown), the “razorgraft” (Gillies), the “mid thickness graft,” etc.

In 1875, John Reissberg Wolfe (I824-I904), of Glasgow, reported the successful repair of a defect about the lower eyelid with a free whole-thickness graft of 2.5 cm × 5 cm from the arm. He is generally accredited with introducing this method. To Fedor Krause (1857-1937) of Altoona, however, is due the credit of bringing whole-thickness grafts into practical use. Free skin grafts based on the original types and methods, either with or without changes in technique, are universally used today.

Since the use of the split-thickness skin graft by Ash in 1870, Ollier in 1872 and Thiersch in 1886, the depth of the graft harvest has been recognized as a crucial factor in donor site healing. This has led to the development of instruments with the ability to control graft thickness to some extent.[6]

Initial attempts to harvest split thickness skin grafts were performed by knives that were simply long cutting blades with a handle at one end and no adjustable mechanism to control graft thickness, such as the Blair knife, Catlin knife and Ferris-Smith knife [Figures 2-4].[7]

Figure 2

Catlin amputating knife for cutting Ollier-Thiersch grafts. Double edged and the size most commonly used had a blade 17 cm long and 1.5 cm wide. From[7]

Figure 4

Thiersch's skin grafting knife, stainless steel, by Weiss, 1920s, London. ‘© British Association of Plastic, Reconstructive and Aesthetic Surgeons’ reproduced with permission from The Curator, Hunterian Museum, Royal College of Surgeons London

Rehn's knife: A very heavy, well-balanced knife. The undersurface was ground flat and the back of the blade nearest the handle roughened to prevent the finger from slipping. Blade -12 cm long and 2.75 cm wide. From[7]

Vilray Papin Blair in 1930 had developed a skin graft knife that came into general use and the grafts were removed with the aid of a suction apparatus that permitted placing the skin under tension. Plastic surgeons became experienced at removing grafts freehand and at controlling the depth by varying the angle of the knife in relation to the skin. Large grafts representing a major portion of the inner aspect of the thigh were removed freehand with great skill by these experts [Figure 5].[6]

Figure 5

Blair's skin grafting knife, chrome plated, by Down Bros, London, with a blade protector. ‘© British Association of Plastic, Reconstructive and Aesthetic Surgeons’ reproduced with permission from The Curator, Hunterian Museum, Royal College of Surgeons London

John Staige Davis J. S., in 1909[8] presented a review of 544 cases that had been skin grafted in the clinic of Dr. Halsted at the Johns Hopkins hospital. He presented a detailed account of the method of cutting skin grafts using the Catlin knife [Figure 6].

Figure 6

Hoffman's knife with guard for cutting Ollier-Thiersch grafts. (a) Knife with guard in place. (b) Knife and guard separated. The guard is secured by two screws (a) that are on the knife itself. The thickness of the graft is regulated by the screws (b) that are on the guard

Hofmann developed a guarded knife in order to obtain grafts of varying thicknesses, the distance between the guard and the knife being regulated by screws. However, the first practical skin grafting knife that permitted precise regulation of the thickness of the skin graft was devised by Ricardo Finochietto.[9] Similar to the Hofmann knife, this was a screw-adjusted knife [Figure 7].

Figure 7

Finochietto knife. Screws for adjusting thickness of the skin graft

The first widely used instrument permitting depth control was that developed by Graham Humby in England who was working at the Hospital for Sick Children, Great Ormonde Street, London, prior to World War II when he was a junior dresser to Sir Heneage Ogilvie.[10] Humby added a roller to the Blair knife. The distance between the roller and the blade of the knife could be varied by means of a calibration device.

Humby[11] evolved a machine that appeared to obviate all difficulties in cutting skin grafts of appropriate size and thickness. It consisted of a rigid rectangular framework that was strapped on the limb. Tiny needles on a crossbar at either end pierce the skin to a depth of one-eighth of an inch and allow stretching of the skin surface, the degree of tension being adjustable by a simple ratchet mechanism. Sliding in the framework is a knife with an adjustable rolling and sliding guard and a disposable blade. Grafts of different thicknesses could be cut with the same instrument by varying the depth of the cutting edge, and simple adjustment regulated their breadth up to the maximum available on the limb [Figure 8].

Figure 8

Humby's rigid rectangular framework for producing a flat donor site (reproduced from[11] with permission from the BMJ publishing group Ltd.)

Two years later,[12] he described a “modified graft cutting razor,” discarding the original large frame to steady the skin and returning to a solid blade that required sharpening. This knife had a rod with two screws on the upper surface to control the thickness of the graft and the roller smoothed out the skin in front of the cutting edge. The width of the graft was determined by the pressure on the knife [Figure 9].

Figure 9

“Modified graft cutting razor” described by Humby in 1936 (reproduced from[12] with permission from the BMJ publishing group Ltd.)

A replaceable blade was reintroduced by Denis Charles Bodenham[1314] for use in carriers equivalent to the standard Blair and Humby knives. The new blades could be easily changed, obviating the need for tedious sharpening that was previously necessary. The advantage of the interchangeable blade, which is now almost universal, is that it gives a much cleaner cut with minimal drag from bluntness, but this is, to some extent, offset by the slight lack of rigidity of the blade that is thin and only partly supported. As a result, the adjustment markings present on the knife give a setting that tends to vary with different blades, and reliance on the markings alone in setting the roller will give inconsistence of graft thickness [Figure 10].

Figure 10

Bodenham's skin grafting knife prototype, made by Bodenham himself: Brass with a steel disposable blade by Gilette, by Bodenham, 1944. ‘© British Association of Plastic, Reconstructive and Aesthetic Surgeons’ reproduced with permission from The Curator, Hunterian Museum, Royal College of Surgeons London

Braithwaite Fenton in 1955[15] introduced a new model combining modifications so that the instrument need not be dismantled to replace the blade. Adjustment between the roller and the blade was achieved by two knurled collars mounted on the back of the knife. The blade was of the wafer razor type and was locked securely in the leaf spring holder. To fit a new blade, it was necessary to move a safety catch, open the leaf and insert the blade under the roller, and replace the safety catch. The knife without the blade could be sterilized by boiling without the risk for damage, and no protective cover was necessary for sterilization or storage [Figure 11].

Figure 11

Braithwaite's skin grafting knife, stainless-steel, by Allen and Hanbury, 1955. ‘© British Association of Plastic, Reconstructive and Aesthetic Surgeons’ reproduced with permission from The Curator, Hunterian Museum, Royal College of Surgeons London

When cutting thin split skin grafts, however, with the Braithwaite knife there is a tendency for the skin to roll up round the guard, and although this can be corrected by an assistant's traction on the cut skin, this maneuver is liable to tear the sheet of skin or cause the knife to cut out.[16] Moreover, the roller must slide to and fro along its long axis, necessitating slack end-bearings that reduce precision in the setting; hence, the graft sometimes becomes gradually thicker as the knife progresses. Usually, two adjustments are necessary at either end of the knife to set the depths of cut; if these are set unequally, the graft will be thicker at one side than the other.

To remedy these disadvantages, Watson John in 1960[17] produced a knife with a fixed, polished, stainless-steel guard and a simpler, more rigid thickness adjustment. This rod has no independent movement, either sliding or rotation, while the graft is being taken. At its end-bearings, it passes eccentrically through the bushes; hence, the depth of cut can be set by rotation of the rod with a single knurled control knob, the rod remaining parallel to the blade at all settings. With this arrangement, the bearings can have a precision fit and there is no “play” in use. While cutting the graft, spontaneous rotation of the rod is slight, but a locking lever is provided to avoid accidental alteration of the setting once it has been made [Figure 12].

Figure 12

Watson's skin grafting knife prototype made following his instructions by Allen and Hanbury. ‘© British Association of plastic, reconstructive and aesthetic Surgeons’ reproduced with permission from The curator, hunterian museum, Royal College of Surgeons London

While this fixed guard effectively dealt with the problem of skin rolling around the guard, it introduced a considerable degree of “drag” due to the inability of the guard to slide to and fro with the skin surface. This drag is only partially eliminated by lubrication with liquid paraffin, and the edges of both graft and donor site tend to be rather ragged when a Watson knife has been used.[18]

Cobbett[16] proposed a modification to this problem of avoiding drag and still preventing the skin rolling around the guard that would be to have a guard that could slide to and fro but could not rotate. Such a modification to a standard Braithwaite knife was made by cutting a “D” section instead of a circular hole in the guard end of one of the cam levers and grinding a corresponding flat on the side of the end of the guard. This modified knife has little drag and no tendency for the skin to roll up on the guard [Figures 13 and 14].

Figure 13

Cobbet's modification of braith waite design reprinted from The Lancet[16] with permission from elsevier

Figure 14

Comparison of major modifications of free hand knives

Some other knives also need mention. Goullian constructed a skin grafts set from a weck straight razor by adding a fixed handle and a choice of interchangeable space setters to cut different thicknesses of grafts.[19] Snow described the use of a shick injector razor to harvest skin grafts.[20] Shoul modified a gillette safety razor by filling out the central strut of the safety guard using another blade as a skim.[21]

Silver from Toronto, in 1959[222324] described a new knife designed for the taking of small grafts, consisting of a razor-blade holder, which carries an ordinary three-holed blade, with a guide to control the thickness of skin cut. The advantages of this knife are its simplicity and the fact that it uses a disposable razor blade [Figure 15].

Figure 15

Silver's knife

Dermatomes

In 1939, the first significant mechanical advance in split thickness skin grafting was made when Dr. Earl Padgett, who, aided by his engineering co-worker George J. Hood, developed a semi-cylindrical calibrated dermatome. It was based on the adhesion-traction principle and gave the surgeon a reliable instrument with which to cut accurately a uniform sheet of skin of predictable thickness in a 4” × 8” size.[25] This instrument became available immediately before World War II and rendered great service to the war wounded as it made possible the cutting of skin grafts not only by the expert plastic surgeon but also by any trained surgeon. During World War II, Reese constructed a more refined dermatome, permitting greater accuracy and control of the thickness of the graft.[9]

Also during World War II, a young American surgeon, Harry M. Brown, conceived the idea of a new instrument, the electric dermatome.(25) Brown was taken prisoner of war during the Bataan campaign in the Philippines, where he conceived the idea of the new instrument while being retained as a prisoner. After the war, he was able to develop the instrument and introduced it in 1948, but, unfortunately, he did not live to witness the magnitude of his clinical contribution as he died in a tragic accident shortly after completing his surgical residency. The original Brown electric dermatome and various modifications of the instrument, which have been developed in the United States, England and France, permit the rapid removal of long strips of split thickness skin, a distinctive advantage in the grafting of the burned patient. Use of the Padgett dermatome, which requires painting the surface of the skin with cement prior to the removal of the graft, is more time consuming when a large amount of skin is needed to cover a large defect, as is often the case in the burns.

The padgett dermatome

The Padgett, or Padgett-Hood, dermatome is an aluminium drum that adheres to the donor site by means of a suitable cement, making possible the excision of a skin graft by an attached blade that rotates around the drum at a distance from the drum that can be varied, either before or during the cutting of the graft [Figure 16].

Figure 16

Padgett-Hood dermatome

The dermatome is made of cast aluminium and the distance between the blade and the drum, calibrated in thousandths of an inch, is adjustable by a ratchet on one side of the blade arm. The instrument usually comes with a thick steel blade that requires sharpening periodically. When the disposable blade is employed, a metal insert or “adapter” is used with the blade, thus increasing the thickness, and the blade and adapter can be held by a metal clamp against the bar on which the blade rests.

The reese dermatome

The Reese dermatome, a carefully machined instrument, is a modification of the Padgett dermatome. The Reese is sturdier and has more precision than the Padgett-Hood dermatome, and is also somewhat heavier and slower in its application. The thickness of the cut is determined by shims that are inserted with the blade to determine the thickness of the graft. The calibration of the thickness of the graft is more reliable than with the Padgett dermatome. However, there is one disadvantage: If it is discovered that the graft is too thick or too thin, it is difficult to change the calibration in the middle of a skin graft removal [Figure 17].[26]

Figure 17

Reese dermatome

The Reese dermatome uses a special tape with a sticky surface, similar to a tire patch, which is applied over the drum. A special glue is applied to the skin so that the skin will adhere to the tape. This tape provides an easy means of carrying and applying the skin. There is some tendency for the skin to bridge any depressed areas in the bed if it is applied with the tape, which could result in small areas in which the graft is lost. In cutting grafts with the Reese or Padgett dermatome, it is important to cut transversely to the part rather than parallel to a convex surface, i.e., transversely across the thigh, abdomen or trunk. There is less tendency for the skin to pull away at the sides of the instrument, and a greater amount of skin can be taken in this manner.

The brown dermatome

The Brown dermatome was the first of the electric dermatomes to be developed, and is especially valuable because, with it, a large amount of skin can be cut rapidly. These instruments do not require the use of cement. The blades are pre-sterilized while the cutting head and rubber-covered cable are autoclaved [Figure 18].

Figure 18

The brown dermatome

The blade is inserted with the blade adjustment set screws opened. The blade is carefully slid into place and dropped over the three rivets before the three anchoring screws are tightened. Both adjustable set screws are then turned down as far as they will go toward zero. They are then opened simultaneously to the desired thickness of the graft calibrated in thousandths of an inch.

The stryker and padgett electric dermatomes

The Stryker and Padgett electric dermatomes are similar to the Brown dermatome, and the indications and applications of these instruments are similar.

The castroviejo dermatome

Ramén Castroviejo Briones (1904-1987) was a famous Spanish and American eye surgeon remembered for his achievements in corneal transplantation. In 1958, developed an electro-keratotome. Originally designed for the dissection of the lamellar corneal grafts, it has also proved useful for cutting buccal mucous grafts for the treatment of eyelid and socket deformities. The instrument is powered by a Norelco shaving motor and has a tiny cutting head with special blades and shims to control the thickness of the cut. The instrument has also been useful as an adjunct in the removal of tattoos after the initial excision has been carried out by either the Brown or the Padgett dermatome. If small areas of tattoo still remain, the Castroviejo dermatome will shave off these residual areas [Figure 19].[27]

Figure 19

The castroviejo dermatome for harvest of mucosal graft (taken from[26] and republished with permission of the American ophthalmological society)

CONCLUSION

Difficulties in obtaining grafts of consistent thickness and quality led to various modifications [Table 1] in skin grafting knives, which paved the way for more sophisticated instruments. The skin grafting instruments form one of the basic tools of the plastic surgeon, and their evolution marks the stages of development of the specialty of plastic surgery as a whole.

Table 1

Major modifications of free hand knives and dermatomes

DISCLOSURE

None of the authors has any financial interests in the products, devices, techniques or drugs mentioned in this article.