This study was designed to evaluate posterior urethral sensation and s
acral reflex evoked by posterior urethral stimulation to predict fate
of pelvic nerve dysfunction. Enrolled were 24 male patients sequential
ly receiving the following examinations 1-3 months (postoperative) and
more then 6 months (follow-up) after surgery for rectal cancer: senso
ry thresholds of the penile skin (SS) and the posterior urethra (SU),
sacral reflex evoked by penile stimulation (BCR) and posterior urethra
l stimulation (UUR), and urodynamic study. Controls included 25 patien
ts with normal voiding function before pelvic surgery. SS, SU and late
ncies of BCR and UUR averaged 1.9 +/- 0.6 mA, 5.6 +/- 1.8 mA, 33.3 +/-
4.2 ms and 65.0 +/- 9.3 ms in controls, respectively, and unchanged p
ostoperatively in 13 patients with normal voiding function. Of 11 pati
ents with voiding dysfunction whose SS and latency of BCR remained unc
hanged, SU increased in 7, voiding function remained unrecovered in 6
patients during the follow-up period and recovered in the remaining 5.
None of four patients with nonevocable UUR recovered voiding function
. Thus, unchanged SU and disappearance of UUR were useful to predict r
ecovery and nonrecovery of postoperative voiding dysfunction, respecti
vely.