Recipient Site Anesthesia and Hemostasis

Hair restoration involves a large number of repetitive, detailed steps performed in an area of skin with a very rich neuro-vascular supply. The generous blood supply allows surgical procedures that would perhaps not be well tolerated by other parts of the body. It also means that intra-operative bleeding can be profuse, which will cause the surgery to be long, frustrating, and difficult, and limits procedure size and precision. Hair surgeons routinely perform procedures on the scalp that would not be attempted unless under general anesthesia in other surgical specialties. Of necessity, we must all be very skilled in the administration of local anesthetics, and particularly vasoconstrictors.

There are several tasks that must be accomplished with injected medications in the recipient site:

1. Anesthesia and hemostasis must be achieved and maintained for the duration of the procedure and beyond.

2. The scalp must be prepared for the incisions in such a way that provides optimum protection for the neuro-vascular structures, to avoid problems of long-term hypoesthesia and vascular insufficiency.

3. This must be done efficiently, with as little patient discomfort as possible.

Achieving these goals and avoidance of side effects requires an understanding of the neuro-vascular anatomy, and delivering the right medication, at the right time, to the right location in the scalp.

The arterial supply to the recipient scalp courses up from below like spokes coming in from the rim of a wheel. The nerve supply differs, however, in that the supraorbital and supratrochlear nerves, which exit the skull under the eyebrow and then run upward, supply most of the anterior half of the recipient scalp. Once these nerves are blocked, the bulk of the anesthesia is done; however, new vessels must be dealt with as we move back in the recipient area. Anesthesia is therefore achieved relatively easily, but good hemostasis requires more preparation, effort, and significant amounts of epinephrine.

In the author’s experience, epinephrine’s ability to produce vasoconstriction is based on several clinical parameters—placement, concentration, time, and distance—in which to act on the vessel. The medication must be injected where the vessels are (the subcutaneous plane), and in a large enough concentration to produce vasoconstriction. But with increasing concentrations comes an increased risk of systemic side effects. By increasing two of the parameters (time and distance), another can be decreased (concentration), avoiding side effects. To this end, dilute tumescent anesthetic (0.1% lidocaine and 1:180,000 epinephrine) can be injected into the recipient area 10–20 minutes prior to incisions being made (before performing the donor harvest). It is always injected 2–3cm beyond the boundaries of the planned recipient zone (“upstream” in the vessel’s path), to allow the epinephrine to act on a greater length of each vessel, producing better vasoconstriction “downstream” in the recipient site. The additional time and distance in which to act on the vessel produce more vasoconstriction than would normally be achieved with such a dilute solution.

More concentrated epinephrine (1:25000 and 1:50000) is then injected in the same area immediately prior to incisions to maximize vasoconstriction and extend the effect as long as possible. Because the more concentrated epinephrine solutions are being introduced into partially vasoconstricted areas, there is little systemic absorption, resulting in fewer side effects and longer lasting local vasoconstriction.

The first part of the anesthetic is a ring block across the forehead and extending into each temple 3cm or so into the hair-bearing scalp. The author uses 4–6cc of buffered lidocaine with epinephrine, followed by tumescent anesthetic. As the main neuro-vascular structures lie below the dermis, and above the galea, it is to this layer that the medications must be delivered. The subgaleal layer is relatively avascular, and as such, medications injected here provide little benefit and serve to increase the risk of forehead edema. Too superficial, and the solution is difficult to inject (increased pressure) and produces a “peau d’orange” appearance in the scalp. Too deep, and you feel the needle tip scraping bone.

It is important to perform the ring block 2–3cm below where the first incisions will be made, as this produces a numb area below the hairline where epinephrine solutions can be comfortably injected later. Running several lines of epinephrine across this area from the block up to the hairline zone will create several “upstream dams” across the vessels. This produces far better vasoconstriction than epinephrine injected only at the sites of the incisions (Dr. James Arnold, personal communication). With the initial ring block complete, the remainder of the surgery will be performed under tumescent anesthesia with additional anesthetics as needed (usually the block is repeated with 0.25% bupivicaine).

Tumescent anesthesia has several advantages in the recipient area. When injected far enough in advance of site creation, it provides very even and long-lasting anesthesia with very little total lidocaine dosage (because of the 0.1% concentration). The epinephrine content is enough to provide initial vasoconstriction, but because of the more dilute concentration (1:180,000), does not cause systemic side effects that may be more likely if greater concentrations were injected into unprepared scalp. The fluid also lifts the skin away from the deeper vessels and the galea, providing extra protection (greater distance from the blade tip) for these structures during site creation. Tumescent anesthetics in the recipient site are not injected to create tense turgor, but just enough to lift the scalp somewhat and produce some vasoconstriction. It is best injected as the needle advances. The spreading fluid creates a “wave” in front of the needle tip, which separates the skin and galea slightly and makes it easier to keep the needle in the proper plane. Because of its dilution, tumescent anesthetic inadvertently injected into a vessel has less potential to cause side effects than standard solutions.

Immediately prior to site creation, the previously tumesced area is injected with 1:50,000 epinephrine in saline. This furthers the vasoconstriction begun by the more dilute solution. The area to be operated on 10–15 minutes later in the procedure is then tumesced. This staged approach of tumescent anesthesia, time interval, and 1:50,000 epinephrine is used over the remainder of the recipient area. More concentrated epinephrine (1:25000) is used for spot hemostasis as needed in small amounts.

Key points to note are as follows:

1. The epinephrine must be injected over enough of the length of a vessel to produce vasoconstriction before the vessel reaches the area of incisions. “Upstream” injections make a more effective flow restriction. When more concentrated epinephrine (1:50000 and 1:25000) is injected into areas that have been previously tumesced, and therefore partially vasoconstricted, systemic absorption of epinephrine is minimal, reducing chances of side effects and prolonging local vasoconstriction.

2. The scalp-elevating effects of these injections reduce bleeding intraoperatively, and may be important in protecting the vasculature.

One of the biggest potential timeconsuming tasks in the surgery is applying pressure, dabbing, spraying, etc., in an effort to keep the site clean. Time spent on systematically preparing the site to prevent bleeding pays dividends in time saved in the remainder of the procedure. Also, reduced bleeding keeps the anesthetic in the area longer. This translates into longer anesthesia for the patient post-op.

When epinephrine is injected to the proper area of the scalp in a staged approach, large amounts can be used without significant systemic side effects. When profound local vasoconstriction is achieved, some of the drug is broken down in the skin itself and any released to the rest of the body is done so very slowly. The author has been using this approach for five years, and has not seen significant increases in BP or HR during the surgery, despite administration of 1.0–1.5mg of recipient site epinephrine during a 3–4 hour surgery.

The potential of recipient site tumescence to cause forehead edema was the author’s main concern with its use. However, the incidence has not appeared to be greater than techniques not using tumescence. In addition, bruising in the forehead has been eliminated and hemostasis has appeared to be superior, and anesthesia longer lasting. The author postulates that with use of tumescence, there is less sub-galeal bleeding and very little between the galea and skin. With little blood in these spaces to track down the forehead, one cannot produce bruising. Also, blood in the extravascular space tends to be irritating and cause inflammation, so less bleeding perhaps means less swelling, despite the additional injected fluid.

Epinephrine is invaluable in hair restoration, but to be at its most effective, large amounts must be given. Tumescent anesthesia offers a safe, effective way to produce long-lasting scalp anesthesia, protect the neuro-vascular structures, and reduce intra-operative bleeding, while at the same time reducing systemic absorption of epinephrine.