Comparing ultrasound-guided cutaneous nerve block of lower extremity and tumescent local anesthesia in endovenous radiofrequency ablation of great saphenous vein incompetence: a randomized controlled trial

Background Endovenous radiofrequency ablation (RFA) is one of the most commonly used treatments for great saphenous vein (GSV) incompetence. Tumescent solution containing local anesthetics is usually administered during the operation. However, the pain caused by multiple puncture injections into the skin causes considerable discomfort for patients. Cutaneous nerve block (CNB) can provide effective pain relief without affecting muscle strength. Therefore, the randomised trial was designed to compare ultrasound-guided CNB of the lower extremity with tumescent local anesthesia (TLA) in RFA for GSV incompetence. Methods Subjects were randomly assigned to either the CNB or TLA group. For patients in the CNB group, ultrasound-guided nerve block was performed targeting four key cutaneous nerves. Standard TLA was administered to patients in the TLA group. Results A total of 98 patients were enrolled and included in the final analysis. For the primary outcome, NRS scores over time differed significantly between the two groups (group × time interaction: F = 54.023, p < 0.001), with CNB maintaining consistently low scores while TLA showed marked increases during critical surgical steps. In a post hoc analysis, the incidence of moderate-to-severe pain in the CNB group during surgery was significantly lower than that in the TLA group (6.12% vs. 46.94%, p < 0.001). All patients exhibited limb muscle strength of grade 4 or above at the end of surgery. The timed up and go test results also showed no significant difference between the two groups ( p = 0.457). Conclusions Compared with TLA, ultrasound-guided CNB provided better intraoperative pain control in patients undergoing RFA for GSV incompetence, as reflected by lower NRS pain scores over time; the lower incidence of NRS > 3 was a post hoc finding. Trial registration The study was retrospectively registered in Medical Research Registration at https://www.medicalresearch.org.cn (registration number: MR-44-25-073372, registration date:25/08/2025), and the Chinese Clinical Trial Registry at www.chictr.org.cn (registration number: ChiCTR2500114259, registration date:09/12/2025, URL: https://www.chictr.org.cn/showproj.html? proj=293374).