Intraoperative recording of the bulbocavernosus reflex.
OBJECTIVE
To demonstrate the feasibility of intraoperative monitoring of the bulbocavernosus reflex (BCR) as an indicator of the functional integrity of sacral nervous structures to aid in preventing their intraoperative injury.


METHODS
Intraoperative BCR was elicited by electrical stimulation of the dorsal penile/clitoral nerve in 119 patients anesthetized with propofol, fentanyl, and nitrous oxide, with short-acting relaxant. Thirty-eight patients underwent surgery without risk, whereas 81 underwent surgery with risk of damage to sacral structures. Different patterns of stimuli were applied through silver/silver chloride disc electrodes placed on the dorsal aspect of the penis in males and over the clitoris (cathode) and adjacent labia (anode) in females. Recordings were made from the anal sphincter using intramuscular wire electrodes introduced within a 27.5 gauge needle, with two electrodes each inserted in the right and left hemisphincter muscles. Preoperatively, some patients had minor urinary problems in controlling their sphincters.


RESULTS
The BCR was reliably recorded without habituation under this anesthetic regime. Optimal stimulating parameters were found to be double pulses (0.5-ms duration), with an interstimulus interval of 3 ms, stimulating rate of 2.3 Hz, and intensity of 20 mA. With these parameters, it was possible to record the BCR intraoperatively in all patients. Isoflurane and nitrous oxide significantly suppressed the BCR, and muscle relaxant completely abolished it.


CONCLUSIONS
We demonstrated that it is feasible, under certain anesthetic regimes, to intraoperatively monitor the BCR in both children and adults (24 d to 74 yr of age) who did not have significantly affected function in sacral nervous structures.
Deletis
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Department of Anesthesiology, New York University Medical Center, New York, USA.
Vodusek
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DB
D000293:Adolescent; D000328:Adult; D000368:Aged; D001003:Anal Canal / Q000294:innervation*; D002420:Cauda Equina / Q000503:physiopathology / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D002987:Clitoris / Q000294:innervation*; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D007223:Infant; D007431:Intraoperative Complications / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010413:Penis / Q000294:innervation*; D010523:Peripheral Nervous System Diseases / Q000503:physiopathology / Q000601:surgery*; D011930:Reaction Time / Q000502:physiology; D012018:Reflex / Q000502:physiology*; D019051:Rhizotomy; D013118:Spinal Cord Diseases / Q000503:physiopathology / Q000601:surgery*