Urinary incontinence after bilateral parasacral sciatic-nerve block: report of two cases

The authors describe the occurrence of urinary incontinence after bilateral parasacral sciatic-nerve blocks.

Two female patients scheduled for bilateral hallux valgus corrective surgery under bilateral parasacral sciatic-nerve block developed urinary incontinence manifested by 3 episodes of enuresis in the first 5 hours after surgery. Physical examination revealed bilateral perineal and gluteal anesthesia and no bladder distention in both patients. Ten hours after block placement, both patients had recovered perineal sensibility and were able to control micturition.

Given the anatomic relations between the sacral plexus and the autonomic and somatic afferent and efferent innervation of the bladder and urethra, the urinary incontinence observed in our 2 patients could be explained by loss of afferent activity by spread of the local-anesthetic solution to pelvic nerves, loss of the efferent innervation of the posterior urethral sphincter by spread of the local-anesthetic solution to the urethral branches of the hypogastric plexus, and loss of external urethral sphincter tonus by block of the pudendal nerves. Anesthesiologists should consider the possibility of occurrence of urinary incontinence when performing bilateral parasacral sciatic-nerve blocks.