Bilateral electrical pudendal nerve stimulation as additional therapy for lower urinary tract dysfunction when stage II sacral neuromodulator fails: a case report

Background Sacral neuromodulation (SNM) has become an effective therapy for patients with lower urinary tract dysfunction (LUTD) who do not respond to conservative treatment. However, an effective treatment strategy for patients who fail SNM has not yet been identified. An option for LUTD is needed when the clinical response to the SNM diminishes. Case presentation A 51-year-old Chinese man presented to an outpatient clinic complaining of difficulty in urination for > 3 years. The patient also complained of urinary frequency and urgency, accompanied by perineal discomfort. He was diagnosed with LUTD based on his symptoms and previous examinations. The patient underwent sacral neuromodulation with a permanent implantable pulse generator (IPG) (provided free of charge by Chengnuo Medical Technology Co., Ltd.; General Stim, Hangzhou, China) in the left buttock, as he participated in the company’s clinical trial to test the long-term effects of IPG. He reported loss of efficacy of the device 3 months after the implantation. We performed bilateral electrical pudendal nerve stimulation (EPNS) therapy for him. After 2 weeks of treatment, he began to report smooth voiding within 2 h after EPNS, and a moderate improvement in urinary frequency, urgency, and perineal discomfort. After 4 weeks of EPNS, the patient reported > 50% improvement in his urination, evaluated with the short form of the International Consultation on Incontinence Questionnaire for Male Lower Urinary Tract Symptoms. He reported smooth voiding, moderate improvements in urinary frequency and urgency, and the disappearance of the perineal discomfort. He also reported improved sleep and erections. The patient was discharged after 8 weeks of EPNS treatment. Conclusion EPNS could be an option as an additional therapy for patients with LUTD who have failed SNM.

Peripheral Nerve Stimulation for Pudendal Neuralgia: A Technical Note

Background Pudendal neuropathy is a chronic, disabling form of perineal pain that involves the pudendal nerve, a mixed somatic and autonomic nerve that originates from sacral nerve roots. Peripheral nerve stimulation of the pudendal nerve can be useful to decrease symptom burden in patients who have failed initial conservative treatment modalities. Methods In this manuscript, we describe an approach to the placement of a peripheral nerve stimulator for the treatment of pudendal neuralgia. We present a case of complex pelvic neuropathy and review the factors that lead to successful placement. Technical aspects of stimulator placement and ultrasound landmarks are reviewed. Results A lateral to medial approach with ultrasound guidance at the level of the ischial spine is likely to facilitate proper lead placement along the course of the pudendal nerve. Aftercare and adherence to postimplant activity restrictions–particularly avoiding use of the extremes of hip flexion and extension for four weeks—lead to the absence of lead migration. Conclusions Pudendal nerve stimulation is an emerging technique for neuromodulation of refractory pudendal neuralgia. Ultrasound-guided pudendal nerve stimulation is a viable technique for neuromodulation of pudendal neuralgia. Optimization of patient selection, ultrasound guidance, and proper adherence to postimplant activity restrictions may be helpful for long-term therapeutic success.

Neuromodulatory effects of pudendal nerve stimulation on bladder hypersensitivity are present in opioid-pretreated rats

Background and objectivesBilateral electrical pudendal nerve stimulation (bPNS) reduces bladder hypersensitivity in rat models and anecdotally reduces pain in humans with pelvic pain of urologic origin. Concomitant opioids are known to alter responses to neuromodulation in some systems. So prior to the development of a clinical trial for purposes of regulatory approval, the preclinical interaction between opioids and stimulation effectiveness was examined.MethodsBladder hypersensitivity was produced by neonatal bladder inflammation in rat pups coupled with a second inflammatory insult as an adult. Morphine was administered acutely (1–4 mg/kg intraperitoneal) or chronically (5 mg/kg subcutaneously daily for 2 weeks prior to the terminal experiment). bPNS consisted of bilateral biphasic electrical stimulation of the mixed motor/sensory component of the pudendal nerves. Visceromotor responses (VMR; abdominal muscle contractile responses to urinary bladder distension (UBD)) were used as nociceptive endpoints.ResultsMorphine produced a dose-dependent inhibition of VMRs to UBD that was naloxone reversible. bPNS resulted in statistically significant inhibition of VMRs to UBD in hypersensitive rats that had received acute or chronic subcutaneous morphine injections.ConclusionsThis study suggests that inhibitory effects of bPNS can still be evoked in subjects who are receiving opioid therapy, thus giving guidance to potential clinical trials seeking regulatory approval for the treatment of chronic bladder pain.