Detrusor underactivity (DU) is a common condition with a prevalence of 13.3% - 24% in female population1. Management of DU remains challenge since no standard treatment is available. This study aims to assess the effect of transurethral bladder outlet surgery (TBOS) in women with DU refractory to pharmacotherapy.

A total of 53 women with DU refractory to alpha-blockers underwent TBOS between March 2013 and December 2018. The DU was diagnosed based on the urodynamic criteria of Qmax ≤12 mL/s and PdetQmax ≤10 cmH2O2. In terms of TBOS procedure, the patients’ urethral length was measured and subsequently the distal position of incision which was 2.5 cm apart from external urethral orifice was marked with a Wolf 24F resectoscope. The incisions were made at the 5-, and 7-o’clock position of bladder neck extending proximally to the ureteral orifice and distally to the marked position. Thereafter, the tissue of bladder neck and proximal urethra was excised between two incisions to make proximal urethra was even with vesical triangle. After the surgery, a 20F Foley catheter was indwelled for one week. The voiding efficiency (VE), post-void residual urine volume (PVR), and uroflowmetry were used to assess the effectiveness of TBOS. Patients with a VE of >90% were considered as the complete responders and those with a VE of 50% - 90% were considered as the partial responders.

The mean age of the patients was 53 ± 16 years (range 28-84) and the median follow-up period was 43 months (ranged 12 to 72 months). Of the 53 patients, 36 (68%) were diagnosed as neurogenic DU, while 17(32%) as idiopathic DU. At baseline, 28 patients required catheterization including clean intermittent catheterization (CIC) and indwelling catheter, and 25 patients presented a significant PVR (>300ml). Besides pharmacotherapy, seven patients also failed to sacral neuromodulation. After the surgery, 49 patients (92.5%) could void spontaneously by abdominal straining and without catheterization. During the follow-up period, eight patients (15.1%) achieved complete response and 33 patients (62. 3%) got partial response. Moreover, the patients’ Qmax and PVR were also significantly improved (Table 1). Interestingly, of the seven patients failed to sacral neuromodulation, six showed a good response to TBOS. In addition, six patients had mild urinary incontinence and no one developed vesicovaginal fistula during the follow-up.

It has been reported that transurethral surgery is effective in improving DU female patients’ lower urinary tract symptoms and recovering spontaneous voiding. The most of reported procedures were transurethral incision of bladder neck. However, we found that the length of urethra varied from 3 to 5.5 cm in women after measuring female urethra. The procedure of classic incision of bladder neck might not achieve the optimal effect for some patients. Based on the results, our procedure could help 77.4% women with DU to get significant improvement, which seems to be higher than 52% reported in the procedure of transurethral incision of bladder neck3. The important limitation of our study is lack of control, which will be solved in our future study.

TBOS is a safe and effective procedure for female patients with DU.

Yu YD, Jeong SJ. Epidemiology of underactive bladder: Common but underresearched. Investig Clin Urol. 2017;58(Suppl 2):S68-S74.
Jeong SJ, Kim HJ, Lee YJ, Lee JK, Lee BK, Choo YM, et al. Prevalence and clinical features of detrusor underactivity among elderly with lower urinary tract symptoms: a comparison between men and women. Korean J Urol 2012;53:342-348.
Jhang JF, Jiang YH, Lee CL, Kuo HC. Long-term follow up and predictive factors for successful outcome of transurethral incision of the bladder neck in women with detrusor underactivity. J Formos Med Assoc. 2016;115(9):807-13.