Art of Slit Making

Introduction

The “slit” means three dimensions puncture wounds or tunnels created by a physician in the skin and subcutaneous tissue in the recipient area for the purpose of insertion of donor hair follicles.

The process of hair transplant is started with slit-making over the recipient area.

Characteristics of a Slit

• Dimension of slit—Depth, Width, Shape

• Angle

• Direction

• 1. Sagittal-Along direction of hair growth
  2. Coronal—perpendicular to the direction of hair growth

• Pattern
  1. Brick pattern (offset)
  2. Row pattern -one behind another

• Instruments for slit making are hypodermic needles of various sizes, rectangular blade, angled blade, blade handle, custom made blade

DIMENSIONS OF SLIT

The depth and width of the slit are important from two points of view. The depth and width shall mimic the dimensions of a graft. If slits are bigger than graft, there will be popping of graft and linear damage to the recipient bed will be more leading to more vascular trauma, which may, in turn, affect graft survival. If slits are smaller than graft size, there will be difficulty in placing them. The forceful insertion will cause crushing or trauma to the graft, which will affect the hair growth. So the slit depth and size shall be adequate for each graft. It is advisable to make different sizes of the slit for 1FU,2FUs,3FUs graft to reduce linear damage to the recipient bed.

A-coronal slits B-Sagittal slits

A shows the coronal slits, which are perpendicular to the direction of the hair. the black lines show slits and yellow arrow shows the direction of hair growth. B shows the sagittal slits which are parallel to the direction of hair growth.

Instruments For Slit Creation

Instruments for slit making are a handle to hold a blade or a needle, and a sharp device for creating a slit in the skin, which can be a hypodermic needles of size No18,19,20 and 21. needle or a blade. the blades cutting edge can be angled or rectangle. the blades commonly used are custom made comes in different size from 0.7. mm to 1.2 mm. Some surgeons used cut to size persona shaving blades.

A-Chisel Blade Handle B- Angled Blades C- Needles

Slits Creation For Different Zones of Scalp

There are three major zones of the scalp. The table shows all the zones and subzones of the scalp with direction, angle of slits, and size of the follicular unit to be implanted in these zones.

Frontal Zone -Anterior hairline including frontal tuft and Temporal triangle

Mid-scalp and parietal fringe

Table -showing the area(zones) of scalp and direction of slits