Catheter-Based Sacral Nerve Block Versus Pudendal Nerve Block in the Treatment of Pudendal Neuralgia: A Randomized Double-Blinded Controlled Trial.

backgroundPudendal neuralgia (PN) severely impacts quality of life, particularly sitting. Uncertainty exists whether catheter-based sacral nerve block with daily intermittent bolus (SNB) or pudendal nerve block (PNB) is more effective. This trial compared their efficacy over 6 months.

methodsA prospective, randomized, double-blinded trial in China enrolled 90 PN patients. Patients were randomized to CT-guided catheter-based PNB near the pudendal nerve or SNB through the third posterior sacral foramen. In both groups, the catheter remained in place for 7 days, and 10 mL of 0.2% ropivacaine was administered once daily as an intermittent bolus, with compound betamethasone administered on Day 7. Primary outcome was pain intensity (VAS) over 6 months; secondary outcomes included patient-reported global outcomes and maximum sitting time at 6 months.

resultsThe SNB group had significantly lower VAS scores at 1 month (2.98 ± 1.47 vs. 3.72 ± 1.08, p = 0.04), 3 months (3.36 ± 1.14 vs. 4.17 ± 1.19, p = 0.02), and 6 months (3.85 ± 1.04 vs. 4.95 ± 1.08, p < 0.0001). Significantly more SNB patients reported excellent/good outcomes at 1 month (83.88% vs. 63.40%, p = 0.04) and 6 months (75.61% vs. 37.50%, p = 0.002). Maximum sitting time at 6 months was longer with SNB (68.56 ± 21.61 vs. 37.65 ± 16.25 min, p < 0.0001). No severe complications occurred.

conclusionsSNB provided superior and sustained pain relief, functional improvement, and patient satisfaction compared to PNB over 6 months in PN patients. Broader sacral root (S2-4) coverage by SNB may enhance efficacy by targeting pudendal neuropathy and central sensitization. SNB may be considered as an intermediate minimally invasive option for selected refractory PN patients in experienced centers, pending larger safety and feasibility studies. SIGNIFICANCE STATEMENT: This first RCT directly comparing catheter-based nerve blocks for pudendal neuralgia demonstrates that sacral nerve block (SNB targeting S2-4) provides significantly superior and sustained pain relief, functional gains (doubled sitting tolerance), and patient satisfaction over pudendal nerve block (PNB) at 6 months. Its broader root coverage likely addresses central sensitization alongside neuropathy. Catheter-based sacral nerve block with daily intermittent bolus may represent an intermediate minimally invasive option for selected patients with refractory PN in experienced centers capable of structured catheter monitoring. Because this trial was not powered to estimate rare infectious complications and required a 7-day inpatient protocol, larger multicenter studies are needed to define safety, feasibility, cost-effectiveness, and the potential for outpatient adaptation.