DERMATOMY, devices

From Big Medical Encyclopedia

DERMATOMAS, devices (grech, derma skin + tome a section, a section) — the tools intended for cutting from a body surface of skin rags of the set form and

the sizes D. apply at various skin plastic surgeries. Offered by Pedzhett (E. S. of Padgett, 1939), D. allowed to implement plastics the big split skin transplant which in a wedge, practice is by the main, leading method of free skin transplantation (see. Skin plastics ). Would be used at treatment with extensive defects of integuments (burns, wounds after excision of hems, the extensive granulating surfaces). The Dermatomny skin plastics allows to close completely even big wound surfaces a skin transplant of the necessary sizes and thickness.

Fig. 1. The scheme of action of the mechanized dermatomes: and — with back and forth motions of the cutting part, 1 — the eccentric roller (sign of rotation of the roller is specified by a semicircular arrow); 2 — a knife; 3 — the case (frame); 4 — the cut-off layer of skin; 5 — the limiter of depth of cutting; the direct arrow specified the direction of movement of a working part; — with rotary motions (sign of rotation is specified by a semicircular arrow) the cutting part (rotor type), 1 — the case; 2 — a knife; 3 — the limiter of depth of cutting; 4 — the cut-off layer of skin; the direct arrow specified the direction of movement of a working part.

By the principle of action of D. divide into two types: with reciprocating (fig. 1, a) and rotary motions of the cutting part of rotor type (fig. 1, b) among which there are both manual, and mechanized devices. Hand tools for starting of the cutting part demand muscular efforts of hands of the surgeon. The mechanized D. receive energy from electric or pneumatic sources. In comparison with manual devices the mechanized tools considerably reduce time of operation and are more convenient in work. Besides, high speed of cutting, existence of adjustable limiters of depth of cutting and width of a dischargeable layer in the mechanized D. provide higher quality of skin transplants in comparison with hand tools: skin rags have insignificant combs on an inner surface of a cut that provides formation of thinner fibrinous commissure between a transplant and a surface, on to-ruyu it is replaced.

Dermatomas with back and forth motions of the cutting part

To manual. this type transplant knives without limiters of depth of cutting with constant and removable edges belong; the knives supplied with limiters of depth of cutting; With lever transfers and animators; the glue D. with a cylindrical contact surface allowing to take a transplant of 10 X 20 cm; Supplied with the vacuum device for fixing of a skin rag to a contact surface in the course of its cutting.

Fig. 2. A domestic electrodermatom with back and forth motions of a knife: 1 — a casing; 2 — a network cord; 3 — a knife; 4 — the regulator of depth of cutting; 5 — the handle; 6 — a cable arm.

The mechanized. with back and forth motions of the cutting part has the remote electric drive (fig. 2) placed in a casing and connected with a working part of the tool the flexible shaft connected to the eccentric roller of a working part by means of the lock. Working part D. consists of the handle and the eccentric roller which is built in it, the case, a knife, the regulator of depth of cutting and mobile limiters of width of a dischargeable rag. In a back wall of a casing there is an opening for an exit of a network cord and a wire of grounding. Rotary motions of the eccentric roller connected with a spindle of the drive will be transformed by means of a fork to back and forth motions of the knife which is movably fixed in guides of the case.

The limiter of depth of cutting is connected with the case through screw couples. During the movement of a working part on the surface of skin in the direction specified by an arrow, the knife cuts off a layer of skin thickness equal to distance between the contact plane of the limiter of depth of cutting and a trimming blade of a knife. Necessary depth of cutting is established by means of screw couples.

Dermatomas of rotor type

Fig. 3. A dermatome of rotor type with a hand gear: 1 — a knife; 2 — a protective cover; 3 — a window of a nozzle; 4 — the nozzle limiting depth of cutting and width of a dischargeable skin rag; 5 — the case; 6 — a flexible shaft; 7 — a reducer with the handle (8).
Fig. 4. A knife to a dermatome of rotor type with a hand gear: 1 — a half of a standard edge from a safety razor; 2 — a pin for fastening of an edge.

Tool with a hand gear (fig. 3) has the case with the rotating spindle installed on bearings, the nozzle limiting depth of cutting and width of a dischargeable skin rag, a knife, the protective cover preventing friction of a lower surface of a knife about skin, a flexible shaft and a reducer with the handle. These dermatomas do possible cutting of a transplant of the set thickness from 0,1 mm and are thicker. Necessary depth of cutting is reached by turn of a nozzle concerning the case. Digital designations on a scale of depth of cutting are visible through a window of a nozzle. Speed of rotation of the handle increases a reducer by 12 times and is transmitted through a flexible shaft to a knife. So, e.g., at rotation of the handle with a speed of 100 rpm the knife does to 1200 rpm. It provides to the tool high efficiency. The knife has an original design (fig. 4). Its trimming blade is executed in the form of the teeth formed by halves of standard edges from a safety razor which are laid on pins of a mandrel. The acting ends of a trimming blade of edges are directed towards rotation of a mandrel. From above edges nestle on a mandrel by means of a special slip and a nut. Diameter of a knife — 68,5 mm that allows to remove skin rags more than 40 mm wide. Knives, similar on a design, are established also in other Soviet

D. V the mechanized D. of rotor type there is an electric drive which is built in the handle in the form of the universal collector engine of the single-phase current connected to a spindle through the lowering gear reducer.

Diameter of a knife, equal 110 mm, provides removal of skin rags with width apprx. 66 mm and practically any length. The trimming blade is formed by six integral edges from a safety razor. High efficiency and a large diameter of a knife allow to apply it to mass preparation of skin in vitro. For small skin plastic surgeries, napr, in the cosmetic purposes, the special model of the rotor type mechanized by D. with the remote electric drive is recommended. As such drive it is possible to use any stomatol, a drill or the grinder with a standard flexible shaft, one end to-rogo by means of the lock with the spring fixer is connected to a spindle of. The cutting elements of a knife are made of four halves of a standard edge for a safety razor. The maximum width of the transplant received by means of this D., 35 mm. Rotary motions of a driving shaft are transmitted through a spindle to the cutting disk which is rigidly connected to it. The limiter of depth of cutting is connected with the case through screw couple. At the movement of working part D. on the surface of the donor site in the direction specified by an arrow, the rotating knife cuts off a layer of skin. By means of screw couple establish the necessary depth of cutting. In some designs screw couple is absent, and change of thickness of a skin layer is reached by movement of a knife in a draw-in attachment.


Bibliography: Kolokoltsev M. V. A dermatome and its use at free skin transplantation, Gorky, 1947; Krendalp. E. and Kabatovyu. T. Medical merchandizing, M., 1974; Ty-chinkina A. K. Kozhnoplasticheskiye of operation, M., 1972, bibliogr.

B. S. Bobrov.

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