DERMATOME

A dermatome is a surgical instrument used to produce thin slices of skin from a donor area, in order to use them for making skin grafts. One of its main applications is for reconstituting skin areas damaged by grade 3 burns or trauma.

1. DERMATOME By SATHISHKUMAR G ([email protected])

2. INTRODUCTION A  dermatome  is a  surgical instrument  used to produce thin slices of  skin  from a donor area, in order to use them for making  skin grafts . One of its main applications is for reconstituting skin areas damaged by grade 3  burns  or  trauma . Dermatomes can be operated either manually or electrically. The first drum dermatomes, developed in the 1930s, were manually operated. Afterwards, dermatomes which were operated by air pressure, such as the Brown dermatome, achieved higher speed and precision. Electrical dermatomes are better for cutting out thinner and longer strips of skin with a more homogeneous thickness.

3. Dermatomes Anatomy The surface of the skin is divided into specific areas called dermatomes, which are derived from the cells of a SOMITE . These cells differentiate into the following 3 regions: (1) MYOTOME, which forms some of the skeletal muscle; (2) dermatome, which forms the connective tissues, including the dermis; and (3) SCLEROTOME, which gives rise to the vertebrae. A dermatome is an area of skin in which sensory nerves derive from a single spinal nerve root (see the following image).

4. Dermatomes of the head, face, and neck.

5. Clinically important dermatomes Upper extremity C6 - Thumb C7 - Middle finger C8 - Little finger T1 - Inner forearm T2 - Upper inner arm Lower extremity L3 - Knee L4 - Medial MALLEOLUS L5 - Dorsum of foot L5 - Toes 1-3 S1 - Toes 4 and 5; lateral MALLEOLUS Other C2 and C3 - Posterior head and neck T4 - Nipple T10 - Umbilicus

6. DERMATOME INSTRUMENTS Free-hand knives Those are manual dermatomes and the term  knife  or  scalpel  is used to describe them. Their disadvantages are harvesting of grafts with irregular edges and grafts of variable thickness. Their operator has to be experienced in their use for optimal results .

7. Types of dermatomes There are several types of dermatomes, usually named after their inventor Knives Drum E lectric Air

8. Knives: Blair/Brown knife . HUMBY knife , similar to the Blair knife with the addition of an adjustable roller which controls the thickness of the graft taken . Braithwaite knife . Watson knife , another modified version of the Braithwaite knife. Cobbett knife , a modified version of the Braithwaite knife. GOULIAN/WECK knife . Silver knife , ideal for the harvesting of small grafts.

9. Drum: Padgett dermatome , was the first rotary drum manual dermatome to be devised. Reese dermatome, accompanying set of shims- permit careful calibration of thickness . Side view of a drum dermatome blade (24) removing a slice of skin (38 and 40).

10. Padgett hood dermatome

11. Electric: Brown SDERMATOME , the first with powered rotation to be developed, used mostly for large skin grafts. It is electrically operated. Castroviejo dermatome , also electrically operated, is a precision dermatome with a small head and controllable thickness, which is most used for   mucous membrane   grafts. Motor mo ve – small cutting head with blade that control the thickness of the cut. Cutting blade on the small power dermatome tends to loss their sharpness rapidly.

12. Air: Air dermatome , the most commonly used dermatome used worldwide today, used mostly for large skin grafts.

13. Zimmer Air Dermatome

14. Zimmer Air Dermatome: The  Zimmer Air Dermatome was the first air powered dermatome designed by Zimmer. The small diameter handle and lightweight design has become a trusted device in hundreds of operating rooms around the world. This device requires annual  preventative maintenance .

15. Advantage Ideal for the harve s ting of small grafts Exceptional maneuverability with less hand fatigue Graft thicknesses up to .030 inch (0.76mm) in easily adjustable .002 inch (0.05mm) increments Safety lever to help prevent accidental activation Width plates range from one to four inches (2.5 to 10cm) in one inch increments Blades are supplied sterile and don’t require lubrication 5,000 – 6,000 cycles/minute high speed cutting action Includes nitrogen hose that exhausts 10 ft. away from surgical site

16. Disadvantage If the graft is too thick or thins, it is difficult to change the calibration in the middle of a skin graft removal once the procedure is over remove the disposable blade to avoid injury to the operator Graft I removed by gentle rubbing with a sponge gauze soaked in normal saline solution cutting blade on the small power dermatome tend to loss their sharpness rapidly Freehand with a knife: Graft with irregular edges and varying thickness

17. Application One of its main applications is for reconstituting skin areas damaged by grade 3 burns or trauma. Dermatome used in skin graft such a plastic surgery, etc    

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