1505 - When Medications and Injections Fail: A Case for the Success of PNS Stimulation for Chronic Neuropathic Pain

Case Diagnosis: A 58-year-old male with chronic neuropathic pain from common peroneal neuropathy who achieved >50% relief after sciatic nerve PNS implantation.

Case Description:

The patient presented with chronic left peroneal neuropathic pain after a traumatic fall and surgically repaired calcaneal fracture. Pain was constant, deep, and achy, radiating from the ankle to the knee. Baseline VAS was 5/10, worsening to 10/10 with activity, limiting daily function. Physical therapy, TENS, and medications (Lyrica, Cymbalta, Norco) provided minimal benefit. Epidural injections and a lumbar sympathetic block yielded < 50% relief. A prior temporary PNS trial improved pain, reduced medication use, and increased activity tolerance. On exam, he demonstrated 5/5 strength, full dorsiflexion, and a positive Tinel sign over the left common peroneal nerve.

Three weeks later, a permanent PNS device (Nalu IPG) was implanted under ultrasound guidance in the left lateral thigh posterior to the sciatic nerve. Stimulation reproduced paresthesias over the painful region, and lead placement was confirmed with fluoroscopy and impedance testing. At three-week follow-up, he reported >50% pain relief with improved function.

Discussions: Conservative measures and nonopioid medications are first-line for neuropathic pain, with injections or blocks as next steps. However, efficacy may be limited by anatomical complexity or overlapping nerve distributions. Neuromodulation, including PNS, offers an alternative by modulating peripheral and central pain pathways. Randomized trials demonstrate significant reductions in pain and opioid use compared with medication alone. Long-term follow-up studies confirm durable relief, with up to 78% of patients achieving >50% pain reduction after PNS implantation. This case supports evidence that PNS can provide substantial and sustained relief even when medications and injections fail.

Conclusions:

PNS represents a safe and effective option for chronic neuropathic pain unresponsive to standard therapies, reducing pain and medication use while improving quality of life.