Effects of a sphenopalatine ganglion block on postcraniotomy pain management: a randomized, double-blind, clinical trial

OBJECTIVE Postcraniotomy pain (PCP) is a common finding after neurosurgical procedures, occurring in as many 87% of patients. The sphenopalatine ganglion (SPG) has a pivotal role in several headache syndromes, and its anesthetic block is currently used in different clinical conditions with benefit. The aim of this study was to evaluate the efficacy of an SPG block (SPGB) via a transnasal approach as adjunctive therapy in reducing pain scores during the postcraniotomy period.METHODS In this single-center, double-blind, randomized controlled trial, patients undergoing elective surgery with a supratentorial craniotomy were randomly assigned to a scalp block, local anesthetic infiltration of the wound, and systemic analgesia during the first 48 postoperative hours (standard therapy), or to standard therapy as well as an SPGB (experimental therapy). According to the available evidence, assuming a 50% reduction in the incidence of the main outcome in patients with an SPGB (vs standard treatment), 82 patients were needed to achieve 80% statistical power in an intent-to-treat analysis. Pain intensity was recorded during the first 180 postoperative days at selective time points (5 times in the hospital, 3 times by telephone interview) with different pain rating systems (a visual analog scale [VAS], numeric rating scale [NRS], and pain assessment in advanced dementia [PAINAD] scale), together with demographic, clinical, and surgical variables and complications. Heart rate and blood pressure were recorded during surgery. Differences in all variables were evaluated using a paired t-test and confirmed through Wilcoxon matched-pairs signed-rank and Kruskal-Wallis tests.RESULTS No complications occurred among the 83 patients enrolled. Statistically significant differences were found in the mean VAS score at postoperative days 0 (p = 0.05), 2 (p = 0.03), and 3 (p = 0.03). The PAINAD scale score showed significant differences between groups at postoperative days 1 (p = 0.006), 2 (p = 0.001), 3 (p = 0.03), and 4 (p = 0.05). The proportion of patients reporting a VAS score >= 3 in the first day after surgery was lower in the SPGB group than in the standard treatment group (71.9% vs 89.5%), although this difference did not reach statistical significance. At postoperative day 180, 5 patients (2 in the control group, 3 in the treatment group) had developed chronic PCP (NRS score >= 3).CONCLUSIONS SPGB is a safe and effective procedure as an adjunctive treatment for PCP management in elective supratentorial craniotomy during the first 4 postoperative days compared with standard therapy. Further studies are needed to better define the clinical impact of SPGB use and its indications. Clinical trial registration no.: NCT05136625 (ClinicalTrials.gov)