Risk Factors and a Nomogram for Prediction of Refractory Pudendal Neuralgia: A Retrospective Multivariate Analysis Study.

Background: Pudendal neuralgia (PN) is one of the most common forms of genital pain. About 4% or higher of patients suffering from chronic pain.

Objectives: The aim of this study was to evaluate the risk factors for prediction of refractory PN (RPN).

Study Design: A retrospective multivariate analysis study.

Setting: This retrospective analysis included 112 patients with PN who received the pudendal nerve block treatment at the Pain Department of General Hospital of People's Liberation Army.

Methods: Univariate and multivariable logistic regression analyses were used for covariates selection. A nomogram was developed to estimate nonresponse to the pudendal nerve block.

Results: The median age of patients and duration of patients were 48.0 and 1.25 years, respectively. Among 112 patients, there were 64 good responders to the pudendal nerve block for neuropathic pain and 48 nonresponders. Multivariate analysis of 112 patients with PN demonstrated high self-rating depression scale scores (> 32) (odds ratio [OR], 95% confidence interval [CI]: 0.11, 0.01-0.77), damage to more than 2 terminal branches (OR, 95% CI: 0.22, 0.07-0.71), sensory deficit at S2-S4 on the dermatome map (OR, 95% CI: 0.22, 0.05-0.90), and duration of pain (> 4 years) (OR, 95% CI: 0.10, 0.03-0.42) were significant prognostic factors for nonresponse to the pudendal nerve block.

Limitations: There are information biases for retrospective analysis, thus making it more difficult to come up with definitive conclusions. Large-scale randomized clinical trials are warranted to evaluate the risk factors for prediction of RPN.

Conclusions: A longer duration of pain was correlated with a worse prognosis of the neurological disease. Patients with depression were prone to nonresponse to the pudendal nerve block treatment. Pain involved in more than 2 terminal branches and small fibers, affected at S2-S4 dermatome map, were considered to poor prognosis.