Lesions of the cauda equina and conus medullaris of the spinal cord after spinal anesthesia are rather uncommon. As the nerve injury to the spinal cord is usually not extensive, the condition may not be obvious and is frequently overlooked. This damage may be responsible, however, for postanesthetic retention of the urine. If the disorder persists, transurethral resection of a portion of the internal sphincter of the bladder may overcome this unfortunate complication.
In a rather complete review of the literature, Light and his associates1 reported several cases of disturbances of the bladder and rectal sphincter after spinal anesthesia. Critchley2 listed this complication as third in frequency after postanesthetic headache and abducens palsy (paralysis of the sixth cranial nerve). He reported 8 cases of the development of retention of urine, all in persons in their sixth and seventh decades with the exception of a woman aged 40. Peirson
Rieser C. SPINAL ANESTHESIA AND INJURY TO THE NERVOUS MECHANISM OF MICTURITION. JAMA. 1941;117(2):98-100. doi:10.1001/jama.1941.72820280001006