31 Anesthesia Techniques Used for Donor and Recipient Areas
Summary
Keywords: preoperative sedation field blocks lidocaine limits tachyphylaxis pain management epinephrine concentrations buffering ring blocks
Key Points
•Minimize pain with distraction techniques and slow infiltration.
•Stage the anesthesia in time intervals for maximum safety and patient medical variability.
•Understand epinephrine and lidocaine concentrations to ensure long-lasting anesthesia.
•Reanesthetize early before patient feels pain to avoid tachyphylaxis.
31.1 A Practical Approach
Proper anesthesia of the donor and recipient areas involves knowledge of facial anatomy as well as the medications being injected. The donor and recipient areas can be anesthetized first with nerve blocks, which are detailed in Chapter 32. After pre-op sedation, the author performs occipital nerve blocks with 1% lidocaine with epinephrine for faster onset of action, utilizing distraction techniques to minimize pain. The remaining donor area may then be reinforced with the occipital field block. The recipient area is addressed with supraorbital and supratrochlear nerve blocks, utilizing a long-lasting anesthetic such as bupivacaine 0.25% with epinephrine. Because of the longer onset of action and duration, the author prefers to do this prior to excising the donor strip.
The sight of any needle or syringe can invoke fear and anxiety in a patient. To avoid this, it is best to approach the patient from behind or from the side. If the patient is awake, be sure to communicate to the patient prior to injection. Telling the patient that the injections may be uncomfortable and may hurt helps mentally prepare the patient and often they have much less anxiety when the anesthesia is complete and it did not hurt at all or was not as bad as they feared.
After the nerve blocks are performed, the patient is placed in the prone position for donor removal. However, some physicians choose to have the patient sitting up when excising the donor area.
31.2 Field Blocks
Field blocks in the donor area are created utilizing the continuous wheal technique inferior to the planned excision site. The average length of the follicular unit transaction (FUT) donor area is approximately 30 cm. For adequate anesthesia, one can inject 0.2 to 0.5 mL of anesthesia per centimeter length for a total of 6 to 15 mL of anesthetic solution. It is critical to monitor your maximum safe lidocaine limit throughout the entire surgery.
Complete ring blocks of the donor and recipient area with 2% lidocaine with epinephrine have been advocated as opposed to 1% lidocaine for longer-lasting anesthesia. However, it is important to be aware of the total limits especially when injecting higher concentrations over a short amount of time. An average circumference of the scalp for complete ring block of both the donor and recipient area is 60 cm in length. Consequently injecting a volume of 0.2 to 0.5 mL/cm length of 2% lidocaine could lead to a total volume of 12 to 30 mL, which exceeds the recommended limit for the average 70-kg person (maximum volume of 25 mL). When utilizing higher percent lidocaine solutions, it is best to inject more superficially in the dermal plane as opposed to the subcutaneous layer where the medication will be more rapidly absorbed. In practice, many physicians have a heavy hand while injecting and they frequently inject more than they think. To provide longer-lasting anesthesia with a quick onset of action and to potentially reduce the total limit of lidocaine, some physicians use a combination of bupivacaine and lidocaine. Wolf has reported benefits using 0.38% bupivacaine, 0.46% lidocaine, and 1:435,000 epinephrine mixture comprising 7.7 mL of 0.5% bupivacaine with 2.3 mL of 2% lidocaine with 1:100,000 epinephrine. Carlos J. Puig has reported 8 to 10 hours of anesthesia using his technique described in Chapter 30.
Following the anesthesia, tumescent solution is injected in the donor area for added vasoconstriction and to elevate the hair follicles and dermis from the underlying vasculature. The Abbasi solution can be utilized, which is comprised of the following: 100 mL of normal saline, 1 mL of epinephrine 1/1,000, and 40 mg of triamcinolone acetate (TAC). This is equivalent to 0.4 mg/mL TAC and 1:100,000 epinephrine. Good tumescence can be achieved with the injection of 10 to 30 mL of the Abbasi solution into the donor strip depending on how firm you wish the donor area to be. There are physicians who will inject a large volume to lift the tissue significantly and create a very firm dense donor strip. The author prefers a modest amount of tumescence, sufficient to lift the tissue slightly and create the necessary vasoconstriction. A few individuals are sensitive to epinephrine and may have transient palpitations and tachycardia, in which case normal saline alone can be utilized.
31.3 Physician and Medication Variability
Following the removal and closure of the strip, up to 6 mL of bupivacaine 0.25% with epinephrine is injected inferior to the suture line. There are conflicting data whether bupivacaine mixed with lidocaine has a benefit or not. In a study of nerve blocks in forefoot surgery, bupivacaine administration 1 hour after lidocaine administration showed a deleterious effect on the duration of bupivacaine compared to bupivacaine alone.2 Additionally, a 1:1 mixture of 1% plain lidocaine and 0.25% bupivacaine showed a shortened duration compared to bupivacaine alone. The dermatology guidelines do not recommend buffering bupivacaine with sodium bicarbonate because precipitation may lead to decreased efficacy.3 However, the literature and experience from hair restoration surgeons has found significant benefit. In a case series of patients treated for carpal tunnel or trigger digit surgery, Best et al found an ideal anesthetic solution providing a mean of 11 hours and 18 min of anesthesia.4 They used a combined 1:1 solution of 2% lidocaine with 1:100,000 epinephrine (4.5 mL) and 0.5% bupivacaine with 1:200,000 epinephrine (4.5 mL) with an additional 0.4 mL of 8.4% NaHCO3. This yields a 9.4-mL solution of 0.96% lidocaine, 0.24% bupivacaine, and 1:156,666 epinephrine.
31.4 Staging the Anesthesia
During hair transplant procedures, physicians may typically exceed the recommended lidocaine limit. This has been presumed to be relatively safe due to the fact that the anesthesia is injected intermittently over several hours. In 1982, Maloney et al measured peak plasma levels after donor and recipient punch grafts. Recipient anesthesia using 2% lidocaine, alternating with and without 1:100,000 epinephrine, was given 30 minutes after donor anesthesia. Peak plasma levels occurred after 15 minutes of the recipient infiltration, which is 45 minutes after donor infiltration. Peak plasma levels correlated with the total dosage of lidocaine administered, which ranged from 5.3 to 12.5 mg/kg.5 There are, however, no recent studies measuring plasma lidocaine levels during follicular unit excision (FUE) and/or FUT megasessions.
The author performs the field block and tumescences one half of the occipital scalp utilizing buffered 1% lidocaine with epinephrine. This half is removed and given to the technicians to begin dissection before the second half of the strip is anesthetized and tumesced except in large FUT cases in which some or all of the recipient sites are created prior to the donor harvest. This protocol ensures one half of the grafts stay in the body longer and the anesthesia is staged even more. Following this step-wise approach to anesthesia provides comfort and safety when performing megasessions. Injection of 50 mL of 1% lidocaine with 1:200,000 epinephrine in multiple increments over 8 hours was demonstrated to be safe in a single prospective cohort study during Mohs micrographic surgery.6 There were no signs of toxicity, and serum lidocaine levels did not approach toxic levels.
By the time the donor is removed, the supraorbital and supratrochlear nerve blocks have taken effect, and minimal additional field and/or ring block of the hairline is necessary except for the lateral temporal hairline. This has the significant advantage of reducing the overall total volume of additional lidocaine. For the field blocks along the hairline, the author does not utilize sodium bicarbonate for buffering as this has been shown to cause facial edema. Others add the epinephrine to the lidocaine in the morning in order to avoid the stinging caused by the low pH of stock solutions.
Anesthesia injections into the frontal hairline typically start approximately 1 cm inferior to the hairline. To maximize anesthesia time and to limit absorption, it is recommended to inject in the dermal plane. You can easily differentiate this plane from the epidermis because injection in the latter requires added force and also creates the “peau d’orange” effect. Any of the pain-limiting techniques previously described may be used, but the most important thing is to go slowly.
31.4.1 Tachyphylaxis
When injecting anesthesia, be careful of tachyphylaxis that occurs when repeat injections of the same dose of local anesthetic leads to a decreased efficacy of the drug. The drug resistance is probably related to the dosing interval and pain progression. When dosing intervals are too long, pain and discomfort develop before redosing, which hastens the development of tachyphylaxis.7 During long procedures, rather than waiting until the patient is feeling pain before reanesthetizing, it may be prudent to touch up the recipient and donor hairline with small quantities of lidocaine and/or bupivacaine to avoid the possibility of tachyphylaxis.
31.5 Tumescent Lidocaine Anesthesia in Hair Transplantation
31.5.1 Introduction
Tumescent lidocaine anesthesia (TLA) is different from tumescent solution, which does not contain lidocaine and is used primarily for vasoconstriction and to separate the hair follicles from the underlying vasculature. In select cases, some physicians prefer to use only saline to tumesce.
Tumescent solutions may have concentrations of epinephrine ranging from 1:25,000 to 1:80,000 to be utilized in select areas for maximum vasoconstriction. The duration of the action of epinephrine on scalp vasoconstriction has been correlated to concentration and was greatest at the concentration of 1:50,000, with a mean time of 40 minutes compared to 1:100,000 (>30 minutes) and 1:200,000 (<20 minutes).8 They also found that vasoconstriction was significantly different at two different injection points on the scalp forehead area when 1:50,000 was used, suggesting differences in vessel size, wall thickness, soft-tissue thickness, and blood pressure.
Drugs that inhibit the hepatic microsomal enzymes cytochrome P450 (CYP1A2 or CYP3A4) responsible for lidocaine metabolism such as erythromycin,9 fluconazole, sertraline, ciprofloxacin, propofol,10 or general anesthesia11 must also be considered. Other contributory health factors may also play a role such as diabetes.12
Dilute anesthetic solutions are thus a means of moderating the risk while providing significant anesthesia and hemostasis throughout the entirety of the procedure. Additionally, they are much less painful to inject. This is confirmed in a study of lidocaine diluted with normal saline in a ratio of 1:30, which proved to be superior to 8.4% sodium bicarbonate buffered lidocaine in a ratio of 1:10.13
31.5.2 Theory
31.5.3 Effectiveness
The effect of a local anesthetic in a given anatomic region depends on a multitude of factors. But two of the most important factors are the concentration and the volume of the local anesthetic. With tumescent anesthesia, the volume is greatly increased with a proportional dilution in the concentration.
The prolongation of anesthesia is explained by increased tissue turgor and exposure of a greater number of vessels to epinephrine, both of which encourage local vasoconstriction and a consequent reduction in systemic drug absorption.
One might think that these beneficial effects would be counteracted by the use of lower concentration anesthetics, but experience in the field of liposuction suggests that this is not the case. Highlighting the variable influence of the local anesthetic concentration, Morganroth et al conducted a study involving 145 patients undergoing Mohs surgery. They compared the effectiveness of 1% lidocaine with 1:100,000 epinephrine against 0.5% lidocaine with 1:200,000 epinephrine and found that the groups had equivalent pain control despite uequal volumes.14
31.5.4 Safety
Theoretical pharmacodynamic considerations explain why the maximum daily dose can be exceeded, namely that (1) dilute solutions have slower systemic absorptions, (2) increased vasoconstriction slows resorption, (3) lidocaine is lipophilic and therefore sequestered in adipose tissue, (4) adipose tissue and therefore lidocaine is removed during the operation, and (5) adipose tissue has a limited vascular supply, thereby moderating drug redistribution from local to systemic circulation.
More important to the hair restoration surgeon is the safe limit without liposuction. Klein and Jeske estimated the risk of lidocaine toxicity without liposuction at a dose of 28 mg/kg and with liposuction at a dose of 45 mg/kg was ≤1/2,000.15 It was estimated that liposuction removed approximately 28% of the lidocaine before it could be absorbed into systemic circulation. Physicians practicing body FUE should take note of this important finding as large volumes would be needed for body FUE. It is also important to note that in this small patient study, patients with any health factors or medications that could interfere with lidocaine metabolism were excluded.
31.5.5 Tumescent Anesthesia in Hair Transplantation
Physicians have modified the original Klein TLA for other surgical procedures. Dr. Gillespie experimented with the formula in an effort to curb the total anesthetic doses in hair transplantation and to demonstrate the safety and effectiveness. His results have been excellent, leading to fewer anesthetic failures and a reduction in patient discomfort despite the absence of parenteral analgesia and sedative hypnotics. Similar to liposuction, he found it offered additional benefits by prolonging the period of lidocaine-induced anesthesia and by improving hemostasis.
Encouragingly, this gain was achieved while keeping the daily dose of lidocaine below the theoretically toxic limit. This is important since the scalp has a higher vascularity and less adiposity, and thus the pharmacodynamics is not comparable to liposuction. It should also be noted that Dr. Gillespie has not experienced an increased rate of postoperative edema compared with more conventional anesthesia. See Video 31.1 and Video 31.2 for demonstrations of tumescent anesthesia and the use of micro cannulas.
31.6 Preparation of Anesthetic Solutions
Initial anesthetic solutions are created by adding 0.5 mL of 1:1,000 epinephrine to a 50-mL vial of 1% lidocaine without epinephrine, yielding a solution of 1% lidocaine with 1:100,000 epinephrine. A second solution of normal saline with 1:100,000 epinephrine is created by mixing 0.5 mL of 1:1,000 epinephrine to a medicine cup containing 50 mL of warmed normal saline.
A third buffered 1% lidocaine with epinephrine solution is made by placing 15 mL of the initial 1% lidocaine solution with epinephrine into an empty medicine cup and combining it with 1 mL of 8.4% sodium bicarbonate. It is important to use plain lidocaine with freshly added epinephrine since commercially prepared mixtures of lidocaine and epinephrine have a very low pH, which significantly increases the pain of injection.
31.6.1 Donor Area
Dr. Gillespie uses 40 mL of buffered 0.2% lidocaine with 1:500,000 epinephrine. To form this solution, 2 mL of the initial buffered lidocaine solution is mixed with 8 mL of warmed normal saline without epinephrine.
Beginning in the midline of the occipital region, injections are placed in an arc curving from the occipital to the temporal donor regions. Using an ergonomic 12-mL Monoject syringe (Fig. 31.1) fitted with a 1-inch 30-gauge needle, slow 2-mL injections are placed into the subcutaneous fat. The pain of injection is greatly reduced by infiltrating anesthetic at a very slow rate. The needle is partially withdrawn and inserted into progressively more superficial plane, with the solution injected during both withdrawal and insertion. This continues until the skin blanches 2 to 3 cm away from the first injection site. Then the needle is completely removed and inserted just proximal to the blanched edge of the scalp. This technique is continued along the length of the donor area. Only the first pinprick is felt.
Fig. 31.1 Kendall Monoject 12-mL Control Syringe. The author uses this syringe for the entire procedure. The finger holes make it a very ergonomic tool when injecting large volumes slowly.
Related posts:
Methods and Techniques to Study Hair Cell Survival
Hair Transplantation: The Promise of Cell Therapy
OSHA, Laboratory Screening, and Office-Based Surgery
The Patient with Minimal Hair Loss: Planning and Decision-Making
The Young Patient: Planning and Decision-Making
Introduction and Definition of Follicular Unit Excision
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