Overview of Recipient Site Creation

39 Overview of Recipient Site Creation

Greg Williams

Summary

One of the critical steps in determining the outcome of a hair transplant procedure is the creation of the recipient site incisions. When learning to make these, there are several key principles involved, including correct and appropriate determination of incision size and shape, depth, angle, direction, density, and geometry. Recipient sites can be premade before starting to place grafts or can be made at the same time as each graft is placed. There are a wide variety of instruments that are used to make recipient site incisions, including blades, needles, and implanters. Multi-incision instruments can be used to potentially increase the speed of site making and robotic technology can be used to eliminate any human fatigue element.

Keywords: hair transplant recipient sites hair transplant incisions size shape depth angle direction density geometry

Key Points

•The creation of recipient sites determines the appearance of a hair transplant.

•Factors to consider when making recipient site incisions include size and shape, depth, angle, direction, density, and geometry.

•Recipient sites can be premade before starting to place grafts or can be made at the same time as each graft is placed.

•There are a wide variety of instruments that are used to make recipient site incisions, including blades, needles, and implanters.

•In the majority of cases, there should be no scarring visible to the patient from the recipient site incisions.

39.1 Introduction

One of the critical steps in determining the outcome of a hair transplant procedure is the creation of the recipient site incisions. Harvesting robust grafts and protecting and implanting them carefully are critical to a good technical outcome in terms of transplanted hair growth rate. Choosing the right patient and determining an appropriate hairline are certainly important in maintaining the long-term overall appearance of the transplant. However, assuming all other steps are managed optimally, it is the pattern of the incisions that will have the most impact on what the patient actually sees.

Whereas much time is spent by patients and professionals discussing and debating the merits of different donor harvesting techniques, it is the skill and artistry involved in the incision site planning and creation that determine the final aesthetic appearance. Consequently, it is this part of the procedure that doctors new to hair transplantation should ensure they learn particularly well and that educators should teach in detail to all levels of learners.

Although patients should certainly be concerned that incisions are made optimally, it is difficult for patients to question a doctor they are considering to do their procedure about the detail of their surgical skill. However, it is less difficult after the surgery is done to ascertain if incisions have been made inappropriately because a resulting poor aesthetic outcome will be visible and, in many cases, permanently so. Doctors should have a clear response, which concisely encapsulates their approach, to inspire confidence in prospective patients.

With the advent of robotic technology, it is now possible for the incision making to be taken out of the doctor’s hands completely. Most other surgical robots cannot run autonomously and require the continuous manual input of the surgeon. However, the only currently available hair transplant robotic device can make the all the incisions within a grid once initiated without any direct input from the doctor. The parameters of the incisions can be from a preset template or determined specifically for each case. There are unique advantages and disadvantages to this (Video 39.1).

39.2 Incisions

It is generally recommended that hair transplant recipient site incisions should only be made by a licensed doctor (or doctor-run robotic device).1 However, in some countries, where it is legal for other licensed, suitably trained, and insured healthcare professionals to make incisions in the skin, it might be considered acceptable for them to make hair transplant recipient site incisions as well.

Although there are very limited formal hair transplant surgery training programs available worldwide, there are several key principles involved in making incisions that should be mastered using cadaveric or synthetic training models available at workshops. These include correct and appropriate determination of incision size and shape, depth, angle, direction, density, and geometry (Table 39.1). To the novice hair transplant surgeon, the creation of an incision may seem like a single simple maneuver, but each one of these six elements needs to be considered every time an incision is made and indeed some elements may vary from incision to incision. Like all other surgical maneuvers, it is only through repetition and practice that skill will evolve. Initially when learning how to make incisions, the doctor should proceed slowly and think about the variables with each incision. With experience, this becomes second nature and incisions can be made with greater speed while still taking into account the different elements of each incision. It should be taken into account that while one incision might only be 1 mm in length, one thousand 1-mm incisions would constitute 1 m of incision. The overall invasiveness of the sum total of all the incisions made in a large hair transplant procedure is very significant and should not be referred to as “nonsurgical” or “noninvasive.”

Table 39.1 Variables to consider when making recipient site incisions

•Size and shape

•Depth

•Angle

•Direction

•Density

•Geometry

39.3 Size and Shape

When referring to “size” of an incision, the reader should take this as the length and width of the cut. However, this can be influenced by the shape and character of the instrument used to make the incision, as well as the angle at which the instrument is introduced into the skin.

There are many different tools currently used to make incisions. Broadly speaking, instruments fall into two categories: blades and needles.

The angle at which a linear blade is introduced into the skin will influence the length of the incision (Fig. 39.1). If it is introduced at 90 degrees, then the length of the incision will be the same as the length of the blade. However, as the angle at which the blade is introduced into the skin decreases, the length of the incision increases.

Fig. 39.1 (a, b) Incision angle affects incision length.

A curved incision such as that made with a hypodermic needle, or implanter, will have a total length longer than a line drawn directly from one end of the incision to the other end of the incision (Fig. 39.2). The length of a curved incision will similarly lengthen as the angle at which the needle or implanter is introduced into the skin becomes more acute.

Fig. 39.2 (a) A curved incision such as that made with a hypodermic needle, or implanter, will have a total length longer than a line drawn directly from one end of the incision to the other end of the incision. (b) The length of a curved incision will similarly lengthen as the angle at which the needle or implanter is introduced into the skin becomes more acute.

The resultant width of the incision in most techniques is more likely to be determined by the characteristics of the skin into which the incision is being made rather than the width of the sharp instrument used to make the incision. An exception to this would be the use of an instrument that removes tissue such as that used in the past to create recipient sites that received “slot grafts.” In this technique, the width of the incision would also be influenced by the width of the tissue excised.

What can be agreed upon is that if grafts are going to be implanted after the incisions are made, the incision should be big enough to insert the graft with minimal manipulation but small enough that the graft fits snuggly, does not pop out, and tamponades any bleeding. A few incisions should be tested initially to ensure the correct size sites are made prior to making all the incisions. This should be done for different sized follicular units (FUs) and in different areas of the scalp. If it is difficult to insert the grafts, then a larger incision can be made either by making the angle of incision more acute or by making the incision longer with a different instrument. The same process should then be repeated to test different size FUs. It should be taken into account when testing the strip follicular unit transplant (strip FUT) grafts that some hair transplant surgical assistants will cut grafts larger than others and this should be known by the surgical team manager. Testing grafts from an assistant who cuts fine grafts might mean that grafts from an assistant who cuts larger grafts might not fit.

39.4 Depth

In addition to testing the width of the incisions, the depth of the incision should also be decided on a case-by-case basis. The required depth will be primarily dependent on the length of an individual’s follicle. This will vary from patient to patient and among different ethnic groups. There will also be some variability in an individual patient. In Caucasian men, the average graft length is 4 mm.

A secondary determinant of incision depth is the quality of the individual’s skin. In the same way that the size of the grafts should be tested, the depth of the grafts should also be tested—ideally prior to tumescence, if this is to be used. Too shallow and the grafts will not sit deep enough and the bulge area with its crucial stem cell population might sit above the level of the surrounding skin and desiccate, leading to failure of the graft growing. Too deep and the graft might sink beneath the surface with burying of the epithelial component of the graft, leading to a “pitted” appearance of the skin postoperatively or, in worst-case scenario, inclusion cyst formation.

Creating a consistent depth to each incision made is dependent on the surgeon. Having an instrument with a “shoulder” will likely produce incisions that are more consistent in depth than those done “free hand.” Many surgeons use custom-made blades that can be clamped in an instrument such as a needle holder. If the required length of the blade is left proud of the needle holder in a longitudinal direction, then the needle holder can act as the “shoulder,” preventing the blade from penetrating deeper than intended. If implanters are used to make incisions, then these have a predetermined length of needle that will create a specific depth on incision. If a hypodermic needle is used to make incisions, then the bevel of the needle can be measured by the surgeon and depth of incision can be gauged by how much of the bevel (and needle proximal to the bevel) is inserted into the skin. A depth-controlling “shoulder” can be created by creating a double bend in the needle.

Another variable to consider when determining the depth of the incision is the force used by the surgeon to create the incision. The softer the skin and the greater the force used, the more the skin will be compressed and the longer the incision will end up being once the skin has relaxed again. This is particularly relevant when there is variability in skin consistency from area to area.

39.5 Angle

The appropriate angle of the incisions depends on the location within the scalp where the hairs are being implanted. Where there is existing hair, a template exists to be followed. Where there is no hair, the surgeon must draw on the experience of observing natural hair angles in different parts of the scalp in both genders as the angle of incision will determine the exit angle of growth of the transplanted hair.2 Angles will vary from a forward 45 degrees in the hairline of most individuals to an upright 90 degrees on the top of the head and then reversing to a very acute angle if simulating the downward hair growth direction in the occipital region.

Incision angle is perhaps most critical when performing eyebrow transplants where the angle should be as acute as possible so that the hairs grow almost horizontally. A similarly critical angle is required in the male temporal points where the hairs tend to lie very flat and almost parallel to the skin. Creating site in a direction perpendicular to the acute angle of growth in these regions can help prevent grafts from being able to slide into a more perpendicular position. Hair angle can vary in natural hairlines and it is important to observe this with loupe magnification as even miniaturized hairs can give clues as to that individual’s pattern of hair growth.

Where recipient sites are being made in areas that have existing hair, the incision angle should follow exactly the angle of exit of any existing hairs to avoid damaging roots and the subcutaneous portion of the hair shafts adjacent to incisions. This is increasingly important the greater the density of existing hair.

The surgeon needs to be constantly aware of the angle with which the incision-making tool is being held in the hand and how this relates to the skin surface. If tumescence has been used, this can cause hairs that are naturally acutely angled to become more obtuse. In this situation, the angle of exit of the naturally occurring hairs should still be followed as the transplanted hairs will revert to the acute angle along with the natural ones when the tumescence is absorbed.

39.6 Direction

The direction of the incision will determine the direction of the hair growth and the overall flow of the hair.³ This can be designed de novo by the surgeon if there is no existing hair in bald areas but should follow the direction of any existing hair. Correct design of hair direction is crucial in the design of whorls in the crown (Fig. 39.3), even more so if there are two or even three naturally occurring whorls that need to be replicated. “Direction” refers to the direction in which the hair is intended to grow. “Angle” refers to the incline of the hair from the skin.