Tissue Laxity Based on Donor Tissue Ballooning

As hair restoration surgery continues to evolve, we are confronted with new challenges. In the past, most surgeries transplanted less than 500 grafts a session. The donor tissue excised was based on obtaining enough tissue to complete the session. Donor wound closure was rarely an issue. However, as we increase the number of grafts per session, scalp elasticity is paramount in dictating the total number of grafts per session that can be removed safely.

In Dr. Bosley’s article, “Reduction of Male Pattern Baldness in Multiple Stages”¹, he devised a system to classify central mid-scalp tissue mobility. He placed two small marking pen dots 10cm apart on the scalp and then he manually compressed the central scalp tissue. He divided the amount of tissue compression into five classifications: Class I tissue was compressible less than 0.5cm; Class II tissue was compressible 0.5–1.0cm; Class III tissue was compressible 1.0–1.5cm which is the most common class; Class IV tissue was compressible 1.5–2.0cm; and Class V tissue was compressible greater than 2.0cm. This technique was very helpful when used as a preoperative scalp reduction tool in predicting the amount of tissue that could be excised. It also could be used as a screening device to assess the appropriateness of offering a scalp reducing procedure to the patient. I have found this system very helpful pre-operatively and/or in a consultation in assessing central mid-scalp and donor tissue elasticity. Unfortunately, with scarring in the donor region and decreased elasticity superior to the ears, Dr. Bosley’s assessment of the mid-scalp tissue laxity doesn’t always translate into an accurate assessment of the donor tissue elasticity. Therefore, I have developed another method that predicts donor tissue laxity more consistently.

The technique that I have employed uses the degree of tissue ballooning that occurs during the injection of the normal saline solution. To create donor tumescence, I inject 30–50cc of saline into the subcutaneous tissue just below the dermis. I do not use the technique of injecting normal saline solution into the dermis. As I tumesce, the donor scalp responds in a predictable manner. I have devised a rough scale used to estimate the scalp elasticity based on this ballooning affect. I attempted to quantitate the ballooning affect that occurred when injecting the normal saline tumescence. Using 1cm as a standard measurement prior to injection, I recorded the degree of stretch that occurred before and after the saline injection. Using the current classification system (no elasticity to marked elasticity), I recorded the degree of change. The amount of change noted from pre-injection and post-injection ranged from 1–3mm of stretch. I personally found the millimeters of difference impractical to use for rapid decision making and width selection of the strip. The visual affect of the ballooning was significantly easier to interpret and apply clinically.

Marked Elasticity: Significant tissue ballooning—allows for a 12mm width or greater of tissue excision.

Mild to Moderate Elasticity: Mild to moderate ballooning—allows for an 8–10mm width of tissue excision.

Minimal to No Elasticity: Minimal to no ballooning—allows for less than a 6mm width of tissue excision.

The above scaling system excludes the use of undermining the inferior and superior flaps of the donor wound. I prefer not to undermine the donor tissue. With tight closures or a need to harvest a greater tissue yield, undermining may be necessary. Dr. Michael Beehner in the May/June 2000 Forum wrote an article entitled “Proposal for Selective ‘Delayed Closure’ of the Donor Area.”² In his article, Dr. Beehner described two chief negatives of undermining. One negative was the tremendous amount of dense scar tissue that forms in the wound as a result. The second negative was the increased likelihood of transecting an artery or large vein, thus comprising the vascular support of the scalp. I believe there are three more negatives with undermining. A third negative is that patients experience greater post-operative pain. A fourth negative is the theoretical risk of hair shaft trauma and follicular injury occurring in the inferior and superior wound edges if the surgical plane is incorrect. Finally, there is a greater risk of hematoma formation occurring in the inferior pouch on the wound.

It should be noted that superior to the ears and extending approximately 5cm posteriorly, the donor tissue is more rigid. Because of this situation, a much thinner width needs to be excised. By using this saline tumescent technique, you can assess where the tissue becomes less elastic and where you should start to taper your excision.

When observing the donor tissue ballooning effect, we can now more accurately assess the tissue elasticity in the donor region. We can now more consistently define the amount of tissue that can now be safely removed without increasing the incidence of wide donor scars or tissue necrosis.