Posterior subgluteal approach to block the sciatic nerve: description of the technique and initial clinical experiences

Randomized Placebo-Controlled Trial of 60-Day Percutaneous Peripheral Nerve Stimulation Treatment Indicates Relief of Persistent Postoperative Pain, and Improved Function After Knee Replacement

OBJECTIVES

Total knee arthroplasty (TKA) is an effective surgery for end-stage knee osteoarthritis, but chronic postoperative pain and reduced function affect up to 20% of patients who undergo such surgery. There are limited treatment options, but percutaneous peripheral nerve stimulation (PNS) is a promising nonopioid treatment option for chronic, persistent postoperative pain. The objective of the present study was to evaluate the effect of a 60-day percutaneous PNS treatment in a multicenter, randomized, double-blind, placebo-controlled trial for treating persistent postoperative pain after TKA.

MATERIALS AND METHODS

Patients with postoperative pain after knee replacement were screened for this postmarket, institutional review board-approved, prospectively registered (NCT04341948) trial. Subjects were randomized to receive either active PNS or placebo (sham) stimulation. Subjects and a designated evaluator were blinded to group assignments. Subjects in both groups underwent ultrasound-guided placement of percutaneous fine-wire coiled leads targeting the femoral and sciatic nerves on the leg with postoperative pain. Leads were indwelling for eight weeks, and the primary efficacy outcome compared the proportion of subjects in each group reporting ≥50% reduction in average pain relative to baseline during weeks five to eight. Functional outcomes (6-minute walk test; 6MWT and Western Ontario and McMaster Universities Osteoarthritis Index) and quality of life (Patient Global Impression of Change) also were evaluated at end of treatment (EOT).

RESULTS

A greater proportion of subjects in the PNS groups (60%; 12/20) than in the placebo (sham) group (24%; 5/21) responded with ≥50% pain relief relative to baseline (p = 0.028) during the primary endpoint (weeks 5-8). Subjects in the PNS group also walked a significantly greater distance at EOT than did those in the placebo (sham) group (6MWT; +47% vs -9% change from baseline; p = 0.048, n = 18 vs n = 20 completed the test, respectively). Prospective follow-up to 12 months is ongoing.

CONCLUSIONS

This study provides evidence that percutaneous PNS decreases persistent pain, which leads to improved functional outcomes after TKA at EOT.

Ultrasound-Guided Subgluteal Sciatic Nerve Block for Pain Management during Endovascular Treatment for Below-the-Knee Arterial Occlusions

PURPOSE

To evaluate the ability of subgluteal sciatic nerve block (SSNB) to provide pain control during endovascular treatment of below-the-knee (BTK) occlusions.

MATERIALS AND METHODS

This randomized prospective controlled study evaluated 60 consecutive adult patients who underwent endovascular treatment for BTK occlusions. The patients were randomized into 2 equal groups; the SSNB group underwent SSNB in the subgluteal space under ultrasound guidance, while the control group received fentanyl as an analgesic. The visual analog scale (VAS) and Face, Legs, Activity, Cry, Consolability (FLACC) scale scores were recorded.

RESULTS

Compared with the control group, the SSNB group showed significantly lower median VAS (0 [range, 0-30] vs 70 [range, 20-100], P < .001) and median FLACC scale (0 [range, 0-2] vs 6 [range, 3-10], P < .001) scores. There was no statistically significant difference between the 2 groups regarding the remaining parameters. There was a very strong correlation between the VAS and FLACC scale scores in both the SSNB (r = 0.805, P < .001) and control (r = 0.950, P < .001) groups. The procedure time and total balloon inflation time correlated with the VAS (r = 0.411, P = .024, and r = 0.402, P = .031, respectively) and FLACC scale (r = 0.431, P = .017, and r = 0.414, P = .022, respectively) scores in the control group but not in the SSNB group (r = 0.364, P = .056, and r = 0.300, P =.085, respectively, for correlation with VAS score and r = 0.730, P = .068, and r = 0.704, P = .075, respectively, for correlation with the FLACC scale score).

CONCLUSIONS

SSNB is a highly effective and safe pain management modality for the endovascular treatment of BTK occlusions.

Ultrasound-Guided Subgluteal Sciatic Nerve Blocks with Stimulating Catheters in Children: A Descriptive Study

We describe our clinical experience of combining ultrasound guidance and nerve stimulation for the insertion of subgluteal sciatic catheters in children. Ten children scheduled for lower limb surgery with a combined general anesthetic and a subgluteal sciatic catheter placement for both operative anesthesia and postoperative pain relief were studied. Under ultrasonographic guidance the sciatic catheter was placed using an 17-gauge 50-mm Arrow continuous peripheral nerve block needle and a 19-gauge stimulating catheter (Stimucath). The minimal electrical current required for muscle contraction on the stimulating needle and catheter differed widely among patients. Based on the visualization of the spread of local anesthetic during injection through the catheter, a successful prediction for the sciatic block was made in all patients. All catheters were successfully placed and provided excellent postoperative pain relief without complications.