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.

Effects of electrode size and spacing on the resolution of intracardiac electrograms.

BACKGROUND: Electrogram fractionation can result when multiple groups of cardiac cells are excited asynchronously within the recording region of a mapping electrode. The spatial resolution of an electrode thus plays an important role in mapping complex rhythms. METHODS: We used a computational model, validated against experimental measurements in vitro, to determine how spatial resolution is affected by electrode diameter, electrode length, interelectrode distance (in the case of bipolar recordings), and height of the electrode above a dipole current source. RESULTS: We found that increases in all these quantities caused progressive degradation in two independent measures of spatial resolution, with the strongest effect being due to changes in height above the tissue. CONCLUSION: Our calculations suggest that if electrodes could be constructed to have negligible dimensions compared with those in use today, we would increase resolution by about one order of magnitude at most.

Potassium channel gene mutations rarely cause atrial fibrillation.

BACKGROUND: Mutations in several potassium channel subunits have been associated with rare forms of atrial fibrillation. In order to explore the role of potassium channels in inherited typical forms of the arrhythmia, we have screened a cohort of patients from a referral clinic for mutations in the channel subunit genes implicated in the arrhythmia. We sought to determine if mutations in KCNJ2 and KCNE1-5 are a common cause of atrial fibrillation. METHODS: Serial patients with lone atrial fibrillation or atrial fibrillation with hypertension were enrolled between June 1, 2001 and January 6, 2005. Each patient underwent a standardized interview and physical examination. An electrocardiogram, echocardiogram and blood sample for genetic analysis were also obtained. Patients with a family history of AF were screened for mutations in KCNJ2 and KCNE1-5 using automated sequencing. RESULTS: 96 patients with familial atrial fibrillation were enrolled. Eighty-three patients had lone atrial fibrillation and 13 had atrial fibrillation and hypertension. Patients had a mean age of 56 years at enrollment and 46 years at onset of atrial fibrillation. Eighty-one percent of patients had paroxysmal atrial fibrillation at enrollment. Unlike patients with an activating mutation in KCNQ1, the patients had a normal QTc interval with a mean of 412 +/- 42 ms. Echocardiography revealed a normal mean ejection fraction of 62.0 +/- 7.2 % and mean left atrial dimension of 39.9 +/- 7.0 mm. A number of common polymorphisms in KCNJ2 and KCNE1-5 were identified, but no mutations were detected. CONCLUSION: Mutations in KCNJ2 and KCNE1-5 rarely cause typical atrial fibrillation in a referral clinic population.