Thigh adductor contraction during transurethral resection of bladder tumours: evaluation of inactive electrode placement and obturator nerve topography.

Thigh adductor contraction occurred in 17 of 160 patients during transurethral resection of newly diagnosed bladder tumours. In 13 of the 17 patients contractions were abolished by changing the site of the inactive electrode from the buttocks to the thigh. The topographic relationship between the obturator nerve and the bladder wall studied radiographically and at autopsy showed that the distance between the bladder and the nerve considerably diminished with increasing bladder volume. Thus, when obturator nerve stimulation occurs during transurethral resection transposition of the inactive electrode from the buttocks to the thigh should be tried first to prevent further stimulation. Moreover, TUR at low bladder volume may reduce the frequency of obturator nerve stimulation.