To investigate the sequalae of unsuccessful mid urethral sling division, the evolution of symptoms and to evaluate the success of further surgery (second division or partial/ complete removal) in resolution of symptoms.

We describe a retrospective case series of 13 women who underwent early division (<12 months) surgery for mid-urethral synthetic sling dysfunction, who were subsequently found to have had incomplete division of sling on transperineal ultrasound scan +/- at reoperation. At first sling division surgery all operation notes documented sling identification and division. We describe initial symptoms, timing and nature of further management and subsequent resolution or persistence of symptoms in this group.

Our patients were gathered from a database of 300 women who underwent treatment at our institution for mid-urethral synthetic sling complications between 2014 and 2023. All patients undergoing treatment for mesh complications at our institution are entered into a database; retrospective data is collected and prospective data added. From this database 13 patients were identified as having sling division surgery prior to presenting to our institute and subsequent transperineal ultrasound +/- operative findings showed an intact (12/13) or incompletely divided (1/13) sling.

The most significant finding was that after unsuccessful sling division surgery all 13 patients were discharged from follow up within 3 months. No patients had further investigation with; flow rates, transperineal ultrasound or urodynamics prior to presenting to our institute. There was no clinical suspicion or awareness of the possibility of incomplete sling division.

In order to be reinvestigated all 13 patients had to represent following discharge, this led to significant delay in definitive management. 11/13 patients underwent a second revision surgery; 9/11 underwent redivision/ partial removal and 2/11 underwent complete removal. The median time to second revision surgery was 92 months. 

All patients on representation had persistent voiding and storage symptoms; which was the reason for the initial (unsuccessful) division surgery, no patients in our cohort had pelvic pain prior to initial division. In addition to the voiding and storage issues in the period following unsuccessful division the group had developed de novo urinary tract infections (7/13) and pelvic pain (9/13).  

Of the 11 patients who underwent second revision surgery, recurrent urinary tract infections resolved all but 1. Of the 8 patients with pelvic pain who underwent reoperation only 1 patient had an improvement in pain. Of the 7 patients with overactive bladder symptoms who underwent reoperation only 3 had improvement of symptoms. 
Of the 2 patients who did not undergo further revision surgery. Both continued to have significant storage symptoms of urge and urge incontinence refractory to medication.  1 also had significant ongoing pelvic pain requiring daily analgesia.  Both reported concern about worsening of urinary incontinence as reasons for declining sling division/ excision.

This case series is the first to describe unrecognized, unsuccessful sling division for post operative voiding dysfunction documented by subsequent objective radiologic +/- operative findings.  
The clinical course shows significant urinary and pelvic pain morbidity subsequent to the failed division although it is difficult to ascribe causation with a retrospective lens.  
These findings suggest that a high index of suspicion and low threshold for investigation should be maintained where clinical symptoms persist after a sling division.