[Cremasteric reflex. Its application to urological diagnosis]

Responses to electrically evoked cremasteric reflex with bulbocavernous reflex and cystometrogram were observed on 55 male adults who have complaints of micturition or sexual disorders. As the reflex centers for these reflexes were localized in the lower spinal segments, the observed results were used for the estimation of the injured loci in combination with clinical symptoms. The cremasteric reflex which was dealt with in this paper was the cremasteric EMG responses evoked by single electric shock applied to the ventromedial surface of the thigh or to the dorsum of the penis. The stimuli used have usually tenfold intensity of the sensory threshold, having 0.2 msec duration. The EMG recording was made with a coaxial needle electrode inserted into the ipsilateral cremasteric muscle at the level of the pubic bone. All 20 controls without neurological disorders showed positive cremasteric responses, and the normal range of the latency and the burst length were 68-77 msec and 52-59 msec, respectively, in case of thigh stimulation. More than half of the patients suffered from the disorders of neural origins showed no reflex even for stronger stimulation. Combining with these data, the diagnostic usefulness for the localization of injuries in patients having disorders in either spinal cord or in cerebral vessels was positive. Cerebral influence to the cremasteric reflex was deduced to be a potentiating factor to elongate the burst duration for stronger stimuli. Further detailed observations would yield useful clues for neuro-urological diagnosis of the lower spinal cord injuries.