Role of 3 Tesla MR Neurography and CT-guided Injections for Pudendal Neuralgia: Analysis of Pain Response.

Magnetic resonance neurography (MRN) has an increasing role in the diagnosis and management of pudendal neuralgia, a neurogenic cause of chronic pelvic pain.The objective of this research was to determine the role of MRN in predicting improved pain outcomes following computed tomography (CT)-guided perineural injections in patients with pudendal neuralgia.This study used a retrospective cross-sectional study design.The research was conducted at a large academic hospital.Patients: Ninety-one patients (139 injections) who received MRN and CT-guided pudendal blocks were analyzed.A 3Tesla (T) scanner was used to evaluate the lumbosacral plexus for pudendal neuropathy. Prior to receiving a CT-guided pudendal perineural injection, patients were given pain logs and asked to record pain on a visual analog scale.MRN findings for pudendal neuropathy were compared to the results of the CT-guided pudendal nerve blocks. Injection pain responses were categorized into 3 groups - positive block, possible positive block, and negative block.Statistical Tests: A chi-square test was used to test any association, and a Cochran-Armitage trend test was used to test any trend. Significance level was set at .05. All analyses were done in SAS Version 9.4 (SAS Institute, Inc., Cary, NC).Ninety-one patients (139 injections) who received MRN were analyzed. Of these 139 injections, 41 were considered positive (29.5%), 52 of 139 were possible positives (37.4%), and 46 of 139 were negative blocks (33.1%). Of the patients who had a positive pudendal block, no significant difference was found between the MRN result and the pudendal perineural injection response (P = .57). Women had better overall response to pudendal blocks, but this response was not associated with MRN findings (P = .34). However, positive MRN results were associated with better pain response in men (P = .005). Patients who reported bowel dysfunction also had a better response to pudendal perineural injection (P = .02).Some limitations include subjectivity of pain reporting, reporting consistency, absence of a control group, and the retrospective nature of the chart review.Pudendal perineural injections improve pain in patients with pudendal neuralgia and positive MRN results are associated with better response in men.MRI, MRN, CT injection, pudendal neuralgia, pudendal nerve, pelvic pain, chronic pelvic pain, pudendal neuropathy.