Can persisting detrusor hyperreflexia be predicted after transurethral prostatectomy for benign prostatic hypertrophy?

Detrusor hyperreflexia (DH) is frequently found in patients with benign prostatic hypertrophy (BPH) and persists in 30-50% of patients after successful removal of bladder neck obstruction by transurethral prostatectomy (TUR-P) or surgical enucleation of the prostate. It would be beneficial for surgeons to be able to identify patients who are at risk of persistent post-operative urinary irritation symptoms and DH. Twenty-three patients who showed DH pre-operatively were included in this study. Of these 23 patients, four had neurogenic bladder because of previous cerebrovascular disease. The other 19 patients were considered to have DH because of BPH. These 19 patients were classified according to their cystometry chart patterns. Pattern 1 was the continual sporadic onset and offset of DH, pattern 2 was a single episode of DH at a bladder volume of <160 mL, and pattern 3 was a single DH episode at a bladder volume >160 mL. Preoperative single-photon emission computed tomography (SPECT) was performed on 14 patients. Cystometric findings at 3 to 6 months after surgery were compared with the pre-operative findings. Four of the six patients with pattern 2 (67%) and all patients with pattern 3 (100%) showed an absence of DH after surgery. In contrast, all five patients with pattern 1 and all four patients with neurogenic bladder showed persistent DH. Compared with pattern 3 patients, pattern 1 patients more frequently complained of urgency before surgery, and their symptoms and uroflowmetry parameters did not improve afterward. Among 14 patients who had pre-operative SPECT, all eight patients with low cerebral blood flow in the frontal region showed persisting DH. Conversely, all six patients with normal SPECT results showed no DH after surgery. When DH occurs repeatedly (pattern 1) or occurs at a bladder volume of <160 mL (pattern 2), there is a greater risk of post-operative irritation symptoms. Abnormal SPECT findings can also predict the post-operative persistence of DH. Combing these two pre-operative examinations allows us to predict better post-operative DH in patients with BPH.