Scalp Nerve Block Options for Hair Growth Injections
For hair growth injections requiring anesthesia, combine regional scalp nerve blocks with local infiltrative anesthesia to minimize patient discomfort while maintaining adequate anesthesia for the procedure. 1
Primary Anesthetic Approach
Regional Scalp Nerve Block Technique
Scalp nerve blocks should be considered as the primary anesthetic method for hair-related procedures on the scalp, as they provide superior pain control with less tissue distortion compared to local infiltration alone. 1
The traditional landmark-based scalp block targets six bilateral nerves 2, 3:
- Supraorbital nerve
- Supratrochlear nerve
- Zygomaticotemporal nerve
- Auriculotemporal nerve
- Greater occipital nerve
- Lesser occipital nerve
Recommended Local Anesthetic Agents
Use lidocaine with epinephrine as the primary agent for scalp nerve blocks, adhering to maximum safe doses of 7.0 mg/kg for adults. 1
Specific agent options include 4, 5, 6:
- 0.5% bupivacaine (15 mL) combined with 2% lidocaine (15 mL) with 1:400,000 epinephrine provides effective anesthesia
- 0.5% ropivacaine provides adequate postoperative analgesia with duration up to 4 hours 5
- 0.5% bupivacaine alone (20 mL total volume distributed across injection sites) effectively blocks hemodynamic and stress responses 6
Technical Execution
Inject 1-2 mL of local anesthetic at each nerve site bilaterally using 25-gauge, 1.5-inch needles, with total volume not exceeding 20 mL. 2
Critical safety steps include 1, 7:
- Prepare injection sites with antiseptic solution 7
- Aspirate before each injection to avoid intravascular administration 1, 7
- Use incremental injections 1
- Inject slowly to minimize discomfort and tissue trauma 7
Adjunctive Measures to Enhance Efficacy
Consider adding hyaluronidase (15 IU/mL) to the local anesthetic mixture to improve block success rates and extend analgesic duration. 4
Additional comfort measures 8:
- Buffer lidocaine with sodium bicarbonate (1:9 ratio of 8.4% sodium bicarbonate to lidocaine) to reduce injection pain 8
- Use warm anesthetic solution to decrease patient discomfort during administration 1
Supplemental Local Infiltration
Combine nerve blocks with local infiltrative anesthesia for follicular unit hair transplantation procedures, as recommended by the American Academy of Dermatology. 1
For infiltrative anesthesia 1:
- Maximum adult dose: 7.0 mg/kg lidocaine with epinephrine 1
- Inject from healthy tissue toward treatment areas 8
- Use the lowest effective dose to minimize systemic toxicity risk 1
Alternative Options for Lidocaine Allergy
For patients with true lidocaine allergy (representing only 1% of adverse reactions), switch to ester-type local anesthetics, 1% diphenhydramine, or bacteriostatic normal saline (0.9% benzyl alcohol). 1
These alternatives are suitable for smaller procedures but have limitations 1:
- Diphenhydramine has longer onset (5 minutes vs. 1 minute for lidocaine) and limited efficacy
- Cross-reaction between amide and ester anesthetics is rare
Critical Safety Considerations
Monitor continuously for signs of local anesthetic systemic toxicity, particularly when using larger volumes for extensive scalp procedures. 1
Key precautions include 1:
- Continually assess and communicate with the patient to monitor for early toxicity signs
- Avoid exceeding maximum recommended doses (500 mg lidocaine for multistage procedures) 1
- Be aware that unintentional spread to facial nerve branches can occur with zygomaticotemporal and auriculotemporal injections 2
Advantages Over Local Infiltration Alone
Nerve blocks provide decreased tissue swelling and distortion, prolonged anesthesia duration, and reduced postoperative discomfort compared to infiltrative anesthesia alone. 1, 8
This is particularly important for hair growth injection procedures where 1:
- Tissue distortion can interfere with accurate injection placement
- Multiple injection sites require extended anesthesia coverage
- Patient comfort during longer procedures is essential