Efficacy of Adding Clonidine to Bupivacaine 0.25% Versus Plain Bupivacaine 0.25% Infiltration in Scalp Blocks for Supratentorial Craniotomy

In a prospective randomized controlled trial Lemos et al. from the Netaji Subhash Chandra Bose Medical College, Jabalpur published in Cureus, to assess whether the addition of clonidine (2 mcg/kg) to 0.25% bupivacaine in scalp blocks improves perioperative analgesia and hemodynamic control during supratentorial craniotomy. Clonidine significantly prolonged analgesia duration and improved perioperative hemodynamic stability, with lower postoperative pain scores, reduced need for rescue analgesia, and decreased intraoperative and postoperative analgesic consumption ³⁾

While the study is prospective and randomized, the sample size of 60 patients (30 per group) is underpowered for robust generalization. The statistical significance of the analgesic duration and pain scores (p<0.001) is compelling, but it is unclear whether the effect size translates into meaningful clinical benefit beyond delayed rescue analgesia. Hemodynamic data is selectively highlighted, and potential bradycardia and hypotension risks with clonidine are underexplored. Additionally, the lack of blinding of the assessors and a placebo control weakens internal validity. The study does not account for potential long-term side effects or the impact on overall surgical outcomes.

Furthermore, all authors are from the same institution, which may introduce confirmation bias, and the journal (Cureus) is known for a rapid and relatively unfiltered peer-review process, diminishing the perceived rigor. There is also an apparent overreliance on short-term numeric rating scales without integrating patient-centered outcomes such as functional recovery or satisfaction.

A modestly conducted RCT with clear findings favoring clonidine as an adjuvant in scalp blocks for supratentorial craniotomy. However, limited sample size, absence of assessor blinding, and potential publication bias lower its clinical impact.

Takeaway for Neurosurgeons: While clonidine appears to improve analgesic duration and hemodynamic stability in scalp blocks, these findings should be interpreted with caution and confirmed in larger, blinded, and multicenter trials before changing practice.

Bottom Line: Promising but preliminary evidence supporting clonidine as an adjunct in scalp blocks. Not yet practice-changing.

Rating: 5.5 / 10

Publication Date: June 3, 2025