To explore the efficacy of sacral neuromodulation (SNM) in the treatment of neurogenic bladder (NB), and to analyze the predictive factors.

The clinical data of 91 patients underwent SNM testing therapy from January 2012 to January 2020 in China Rehabilitation Research Center were reviewed. There were 53 males and 48 females with the average age of 36.5(28.0-52.5)years. Urinary diary, residual urine, neurogenic bowel dysfunction score (NBDS), video-urodynamic and pelvic floor electrophysiological examination before treatment were recorded. Among the 91 patients, 60 patients had symptoms of urinary storage period, including urgency, frequency and / or incontinence.The average number of voids/24 h was 13 (11, 18), the average volume per void was (123.0±45.9) ml, the average degree of urgency was (3.5±1.0), and the average 24-hour urine leakage was 100.0(50.0, 231.5) ml. 78 patients had chronic urinary retention symptoms, and the average post-void residual volume (PVR) was 200.0 (132.3, 300.0) ml. The neurogenic bowel dysfunction score (NBDs) of 91 patients was 11 (6.25, 13). The mean maximum cystometric capacity (MCC), maximum detrusor pressure (P_detmax) and bladder compliance were 250 (117, 369) ml, 33 (17, 72) cmH₂O and 8.275 (4.540, 20.307) ml / cmH₂O, respectively. Pelvic floor electrophysiological examination showed that somatosensory evoked potential (SEP) was normal in 39 cases, abnormal in 19 cases and undetected in 33 cases. Bulbocavernosus reflex (BCR) was normal in 39 patients, abnormal in 23 patients and undetected in 29 patients. At the end of the test phase, the patient was re-evaluated. If " effective" or the patient willing to implant, permanent implantation of pulse generator was done. " Effective" was defined as improvement of more than 50% in at least one of the following conditions, including the number of voids in 24 hours, volume per void, degree of urgency, leakage volume in 24 hours, PVR. Quantitative values were compared using the t-test or non-parametric test. The potential risk factors were considered by logistic regression analysis.

The average test time was (18.7±6.7) days. 43/60 patients (71.7%) had improvement of more than 50% in at least one symptom of the storage period, and 21/78 patients (26.9%) had more than 50% improvement in urination symptoms. NBDS decreased from 11(6.25, 13) to 3(0, 8)(P < 0.05). During the filling period, MCC increased from 173.0(98.0, 326.0) ml to 300.0(201.0, 386.0) ml ( P<0.05), P_detmax decreased from 40.0(27.0, 84.0) cmH₂O to 22.0(15.0, 60.0) cmH₂O (P < 0.05), and bladder compliance increased from 6.84(3.75, 11.79) ml/cm H ₂O to 19.23(4.95, 32) ml/cm H₂O (P < 0.05). At the end of the test phase, 54 (59.3%) patients underwent permanent implantation. The median follow-up was 25.5 (11.5, 60.5) months. Four patients lost their curative effect, two patients developed grade 2 vesicoureteral reflux, and one patient underwent cystoplasty. Risk factors analysis showed that chronic urinary retention was a statistically significant variable ( P<0.05).

SNM can not only improve the lower urinary tract symptoms of patients with neurogenic bladder, but also improve the urodynamic parameters and bowel function. Patients with chronic urinary retention symptoms before treatment experienced low efficiency at the end of the test phase.

Sacral neuromodulation; Neurogenic bladder; Efficacy; Predictive factors