Vesicolevator reflex. Description of a new reflex and its clinical significance.

A new reflex which I call "vesicolevator reflex" was studied in 21 healthy volunteers with a mean age of 36.3 years. The technique comprised the introduction of a catheter, with a balloon at its distal part, into the empty urinary bladder. A concentric needle electrode was inserted into the levator ani muscle. The vesical balloon was inflated with air in increments of 50 mL and the levator myoelectric activity recorded by a standard EMG apparatus. Vesical balloon was then removed, and levator EMG response to sudden suprapubic vesical compression was recorded with urinary bladder both empty and filled with saline in increments of 50 mL. Vesical balloon distention evoked levator muscle contraction; duration of contraction increased with increased vesical distention. Levator response to vesical distention did not occur when air-filling was below 50 mL air and when muscle was anesthetized. The latency of the reflex was calculated. Suprapubic manual compression of the empty urinary bladder did not cause levator contraction; yet, compression of distended bladder evoked the response. Compression should be sudden, while the patient is lying supine. Slow insidious compression did not evoke levator contraction. The vesicolevator reflex seems to play a role in the act of micturition, and hence could serve as a tool in investigating patients with micturition disorders.