Ultrasound-guided 5% dextrose neural prolotherapy injection for perforating cutaneous nerve entrapment in chronic coccydynia: a randomized placebo-controlled double-blind trial
摘要
Chronic coccydynia is a multifactorial pain condition, and recent anatomical studies suggest that perforating cutaneous nerve (PCN) entrapment at the sacrotuberous ligament (STL) may represent an overlooked neuropathic mechanism.
AimsTo evaluate the effectiveness of ultrasound-guided 5% dextrose (D5W) neural prolotherapy targeting the PCN innervation zone and the STL in patients with chronic coccydynia.
MethodsThis prospective, double-blind randomized placebo-controlled trial included 32 female patients with chronic coccydynia. Participants were allocated to D5W neural prolotherapy (n=16) or saline injection (n=16). Interventions consisted of ultrasound-guided perineural D5W injections at two levels: deep at the STL entrapment zone and subcutaneous at the PCN innervation zone, performed in three weekly sessions. Pain intensity (VAS), pain pressure threshold (PPT), pain-free sitting duration, and EQ-5D-3L scores were recorded at baseline, after the third session, and at 1 and 3 months.
ResultsThe D5W group demonstrated significant improvements in all clinical parameters over time (p<0.001). VAS decreased from 81.8±9.2 mm to 37.0±27.2 mm at 3 months; PPT increased from 1.5±0.5 kg to 2.9±1.4 kg; and pain-free sitting duration increased from 18.1±9.6 to 71.8±42.7 minutes. EQ-5D-3L scores improved significantly at all follow-ups. The saline group showed no significant changes. Between-group comparisons favored D5W beginning from the third session onward. No adverse effects were observed.
ConclusionsUltrasound-guided neural prolotherapy with D5W targeting the PCN innervation and STL entrapment zone is a safe, effective, and reproducible treatment option for chronic coccydynia. This study provides the first randomized controlled evidence supporting its clinical utility in PCN entrapment–related pain.