EFFECT OF SPINAL-ANESTHESIA ON THE LOWER URINARY-TRACT IN CONTINENT WOMEN

Objective To evaluate the effect of spinal anaesthesia on the bladder neck position and the urethral closure function in the resting state a nd during clinical stress test in healthy, continent women. Design Con trolled clinical trial. Setting Department of Gynaecology and Obstetri cs, Vienna University Medical School. Participants Fourteen continent women, of which seven were nulliparous and seven parous, underwent min or gynaecological procedures under spinal anaesthesia. Urodynamics and ultrasound investigations were performed before and during spinal ana esthesia. Main outcome measures Changes in the bladder neck position a nd the urethral closure function before and during spinal anaesthesia. Results Bladder neck position was found to be lower and more posterio r during spinal anaesthesia as compared with pre-operative assessment. The posterior urethrovesical angle increased significantly both at re st and during maximum straining. We observed a significant increase in bladder compliance, and all parameters of the urethral pressure profi le decreased significantly. While none of the nulliparous women had a positive clinical stress test during spinal anaesthesia, 4/7 parous wo men demonstrated leakage (Fisher's exact test, P = 0.003). Conclusions Blockage of nerve supply to the pelvic floor muscles in continent wom en is associated with a significant loss of support of the bladder nec k region confirming the theory of an active mechanism of muscular elem ents providing continence.