The Bulbocavernosus Reflex in Urology: A Prospective Study of 299 Patients

Abstract

Bulbocavernosus reflex was evaluated clinically in 299 patients during a routine urodynamic evaluation and compared to the electromyographic [EMG] demonstration of the reflex. The findings were correlated with the neurologic status of the patients. There were 127 patients who were normal neurologically, and 98% of the male and 81% of the female patients in this group had a normal bulbocavernosus reflex clinically. All of the male and 92% of the female patients had a bulbocavernosus reflex demonstrated by EMG. There were 73 patients with neurologic lesions involving the sacral spinal cord. All patients with a complete lesion had absent bulbocavernosus reflexes clinically and on EMG, while 44% of the patients with incomplete sacral lesions had an intact bulbocavernosus reflex clinically, and 78% had reflex demonstrated by EMG. There were 99 patients with neurologic lesions of the spinal cord above the sacral outflow, and 90% of this group had demonstrable bulbocavernosus reflexes clinically and 93% had the reflex demonstrated by EMG. Apparently, the absence of a bulbocavernosus reflex in a male patient is indicative of a neurologic lesion involving the sacral spinal cord, and is highly suggestive of such a lesion in a female patient. The presence of a normal bulbocavernosus reflex in either sex does not rule out the possibility of a significant lesion. The EMG demonstration of the bulbocavernosus reflex is more sensitive than the clinical one.