Detrusor sphincter dyssynergia (DSD) is present in 70 to 100% of patients with supra-sacral spinal cord injury (SCI).  If untreated, DSD can lead to severe complications e.g. autonomic dysreflexia (AD), recurrent urinary tract infections (UTI), and short-term renal failure. 
Although the gold standard for DSD management remains intermittent catheterization (IC), combined with antimuscarinic drugs or botulinum toxin injections, to provide complete bladder emptying and low pressure reservoir, in order to protect the upper urinary tract. External sphincterotomy (ES) with reflex voiding has generally been considered the alternative option in men who are unable to perform IC, either through the native urethra or through a continent cutaneous urinary diversion. The objective of our study was to assess the efficacy of ES in men suffering of DSD and unable to perform IC.

Retrospective, monocentric study, enrolling all consecutive patients who underwent a first ES between January 2003 and June 2018, with at least two years of follow-up. The success of ES was defined by the maintenance of reflex voiding mode at the end of the follow-up. Data related to early postoperative complications, reoperation, morbidity (upper urinary tract infections, AD, rehospitalisation...), urodynamic and functional outcomes were collected.

Fifty-one patients were enrolled : 36 (70.6%) SCI patients (including 27 tetraplegia) and 15 (29.4%) multiple sclerosis. The median age was 51 years [41.6;61.2] and the median follow-up was 55 months [34.9;103]. All the patients had a preoperative detrusor pressure at maximum flow (Pdet-Qmax) > 40cmH20 during voiding cystomanometry. The success rate was 80%, with 41 patients still in reflex voiding at last follow-up. A second ES was required for 39% of patients (n=20) with a median delay of 35.9 months [15.0;65.0]. At last follow-up, a significant improvement in AD (26 vs 7 patients, p<0.001), and a significant decrease in urinary tract infections (UTI) (31 vs 15 patients, p< 0.001) and in  post-voiding residuals (200 vs 50 mL, p< 0.001) were observed.

Ten patients (20%) had to change their voiding mode as follows: 3 patients (6%) with indwelling catheter and 7 ileal conduits (14%). For 5 of them, the failure was related to a secondary decrease of detrusor contractility. No significant difference was observed in the preoperative Pdet-Qmax between the 2 groups (success and failure).

ES allowed to maintain reflex voiding in 80% of our patients. It significantly improves AD and UTI despite a high reoperation rate (39%). A long-term follow-up is mandatory in order not to ignore a recurrence of bladder outlet obstruction or a decrease in detrusor contractility, which may justify a re-operation or an alternative bladder management.