Use of a specific questionnaire and perineal electromyography to assess neuropathic pain after radical retropubic prostatectomy

OBJECTIVE: Prostate cancer is the most frequent cancer in men and radical retropubic prostatectomy (RRP) is one of the first-line treatment. However, RRP has some side effects and can lead to chronic perineal pain. The objective of the study was to determine in patients suffering from perineal pain after RRP the possibility of a neurogenic damage by means of a specific questionnaire dedicated to track down neuropathic pain. METHODS: Forty patients were explored by a specific and validated questionnaire, the Neuropathic Pain Symptom Inventory (NPSI). Patients were divided into two groups: Group A with an NSPI score ≥4 was considered as suffering from neuropathic pain, and Group B was considered as a control group without neuropathic pain (NSPI score <4). All patients had a perineal electrophysiological testing to confirm the possibility of a neurogenic damage. RESULTS: Group A was composed by 13 men and Group B by 27 men, with mean age 72.45 years and mean duration of pain 2.7 years. In Group A, the most frequent symptoms were burning sensation, electrical shock and numbness. Location of the pain was global perineal area (8/13), anus (10/13), penis (5/13) and glans penis (2/13). Electromyography (EMG) findings confirmed the presence of denervation and neurogenic damages compared with controls (p < 0.001). CONCLUSION: One third of the patients consulting for chronic pain following RRP had probably a neuropathic lesion leading to a chronic perineal pain as suggested by an NSPI score ≥ 4 and EMG alterations.