Pulsed Radiofrequency Ablation of Pudendal Nerve for Treatment of a Case of Refractory Pelvic Pain.

Pudendal neuralgia (PN) is a result of pudendal nerve entrapment or injury, also called "Alcock syndrome." Pain that develops is often chronic, and at times debilitating. If conservative measures fail, invasive treatment modalities can be considered. The goal of this case report is to add to a small body of literature that a pulsed radiofrequency (PRF) ablation can be effectively used to treat PN and to show that high resolution MR neurography imaging can be used to detect pudendal neuropathy. CASE PRESENTATION We present a case of a 51-year-old woman with 5 years of worsening right groin and vulva pain. Various medication trials only lead to limited improvement in pain. The first diagnostic right pudendal nerve block was done using 3 mL of 0.25% bupivacaine with 6mg of betamethasone using a transgluteal technique and a target of the right ischial spine; this procedure resulted in ~8 hours of > 50% pain relief. The patient was then referred for MR neurography of the lumbosacral plexus. This study revealed increased signal of the right pudendal nerve at the ischial spine and in the pudendal canal, findings consistent with the clinical picture of PN. Six weeks after the initial block, the patient underwent a second right transgluteal pudendal nerve block, utilizing 3 mL of 0.25% bupivacaine with 40 mg of triamcinolone acetonide; this procedure resulted in ~8 hours of 100% pain relief. Satisfied with these results the patient decided to undergo pudendal nerve PRF ablation for possible long-term relief. For this therapeutic procedure, a right transgluteal approach was again utilized. PRF ablation was performed for 240 seconds at 42° Celsius. Following this ablation the patient reported at least 6 weeks of significant (> 50%) pain relief. DISCUSSION AND CONCLUSION In this paper we presented a case of successful treatment of PN with PRF ablation and detection of pudendal neuropathy on MR neurography. We believe that transgluteal PRF ablation for PN might be an effective, minimally invasive option for those patients that have failed conservative management. MR neurography employed in this case is not only helpful in confirming the diagnosis of PN but could also be useful in ruling out other causes of pelvic pain, such as genitofemoral neuropathy, endometriosis, adenomyosis, or pelvic mass lesion. To conclude, transgluteal PRF ablation can serve as a viable treatment option for mitigating symptoms of pudendal neuropathy and MR neurography is useful in confirming a clinically suspected diagnosis of PN.Key words: Pelvic pain, pudendal neuralgia, MR neurography, pulsed radiofrequency ablation, transgluteal technique, Alcock canal syndrome.