Ultrasound-guided superficial cervical plexus blocks for persistent pain after suboccipital craniotomies: a randomized trial.

Background: The efficacy of superficial cervical plexus blocks for reducing persistent pain after craniotomies remains unclear. We therefore tested the primary hypothesis that preoperative ultrasound-guided superficial cervical plexus blocks reduce persistent pain 3 months after suboccipital craniotomies.

Methods: We conducted a single-center randomized and blinded parallel-group trial. Eligible patients having suboccipital craniotomies were randomly allocated to superficial cervical plexus blocks with 10 ml of 0.5% ropivacaine or a comparable amount of normal saline. Injections were into the superficial layer of prevertebral fascia. The primary outcome was the incidence of persistent pain three months after surgery.

Results: From Nov 2021 to August 2023, 292 qualifying patients were randomly allocated to blocks with ropivacaine (n=146) or saline (n=146). The average ± SD age of participating patients was 45±12 years and the duration of surgery was 4.2±1.3 hours. Persistent pain 3 months after surgery was reported by 48 (34%) of patients randomized to ropivacaine versus 73 (51%) in those assigned to saline (relative risk 0.66; 95% CI, 0.50 to 0.88; P = 0.003) in the per-protocol population, and by 53 (36%) of patients randomized to ropivacaine versus 77 (53%) in those assigned to saline (relative risk 0.69, 95% CI, 0.53 to 0.90; P = 0.005) in the intention-to-treat population.

Conclusion: Superficial cervical plexus blocks reduce the incidence of persistent incisional pain by about a third in patients recovering from suboccipital craniotomies.