Sphincterotomy, Artificial Sphincters, Stents and Related Approaches for Bladder Emptying
Transtherurethral sphincterotomy and related procedures, such as insertion of artificial sphincters, sphincteric stents or balloon dilation of the external urinary sphincter, provide a means to overcome persistent dysynergia (Chancellor et al. 1999; Juma et al. 1995; Chancellor et al. 1993a; Chancellor et al. 1993b; Patki et al. 2006; Seoane-Rodriguez et al. 2007). Often these are performed when intermittent catheterization is not an option because of a lack of manual dexterity and when more conservative options have proven unsuccessful (Chancellor et al. 1999; Juma et al. 1995). With the success of transvaginal tape implantation in patients of non-neurogenic stress incontinence, Pannek et al. (2012) sought to evaluate its use for neurogenic stress incontinence in females with SCI but results were unfavourable.
Discussion
A common surgical method of treating bladder outlet obstruction or detrusor-sphincter dyssynergia has been transurethral sphincterotomy usually conducted in anticipation of emptying the bladder with condom drainage with reflex voiding. Autonomic dysreflexia, a common complication of high volume storage and/or high pressure voiding or leaking in those with SCI typically above T12, can be diagnosed with blood pressure monitoring during cystometrogram and urodynamic studies and subsequently better managed after successful transurethral sphincterotomy (Perkash 2007). Perkash (2007) noted a significant (p<0.0001) decrease in systolic and diastolic blood pressure after transurethral sphincterotomy as well as improved voiding and post-void residuals. However, although diminished symptoms of autonomic dysreflexia were reported, mean maximum voiding pressures changes were not significant.
Juma et al. (1995) conducted a pre post-test of 63 individuals who had received one or more sphincterotomies with a mean follow-up time of 11 years (range 2-30). This study was directed at describing the risk for long-term complications following this procedure. Although more than half of these individuals had normal upper tract imaging studies a significant proportion had complications with 25 of 63 individuals having some upper tract pathology (i.e., 12 renal calculi, 11 renal scarring, 1 atrophic kidney, 1 renal cyst), with nineteen deemed significant. Risk of significant upper tract complications in presence or absence of bacteria was 38% and 13%, respectively. Thirty out of 63 individuals had lower tract complications (i.e., 5 bladder calculi, 10 recurrent UTI, 3 urethral diverticula, 6 urethral stricture or bladder neck stenosis and 6 recurrent epididymitis). These authors noted that the most reliable urodynamic measure for predicting potential complications following sphincterotomy appeared to be an increase in leak point pressure. Complication rates of 50% were noted for those with leak point pressure of >70 cm H2O, whereas rates were reduced to 25% when leak point pressure was <30 cm H2O.
Despite possible upper renal tract protection and extended periods of satisfactory bladder function (i.e., 81 months), long-term outcome data (Pan et al. 2009) caution that high rates of recurring bladder dysfunction symptoms (68%) require approaching sphincterotomy as a staged intervention given that 36% (30/84) of patients required a second procedure to achieve the mean extended period of satisfactory bladder function. When considering these studies, it is uncertain if these high complication rates would be comparable in the event individuals had continued with their previous form of bladder management as often surgical procedures are performed only if other more conservative methods are unsuccessful. A controlled trial is required to address this issue. For cases where DESD is paired with with bladder neck dyssynergia, (which should be confirmed with videourodynamic study), Ke and Kuo (2010) have shown that transurethral incision of the bladder neck (TUI-BN) may restore contractility of the detrusor. Post-void residual volume decreased and QMax increased significantly after TUI-BN and an open urethral sphincter was noted in 19 of 22 patients studied postoperatively. In addition, autonomic dysreflexia during micturition was also reduced or eliminated in 15 of 17 patients with preoperative autonomic dysreflexia (Ke & Kuo 2010).
One alternative to sphinterotomy is placement of a stent passing through the external sphincter thereby ensuring an open passage. Several studies have been conducted examining the long-term outcomes associated with different types of stents including a wire mesh stent (UroLume) (Chancellor et al.1993b, Abdill et al. 1994, Rivas et al. 1994; Chancellor et al. 1995; Abdul-Rahman et al. 2010) and a nickel-titanium alloy tightly coiled stent (Mehta & Tophill 2006). Long-term outcomes of each of these stents were also investigated in a retrospective case series study of 47 consecutive male patients (Seoane-Rodriguez et al. 2007). All of these studies involved either retrospective case series reviews or prospective pre-post study designs and demonstrated effective treatment of incontinence initially while the stent was in place although some studies also showed the necessity for stent removal/replacement due to migration or other complications. In particular, Mehta and Tophill (2006), in a case series of 29 persons with SCI with a follow-up of up to 47 months, suggested that the “working life” of the Memokath stent was 21 months. They noted that complications most commonly leading to removal included stent blockage by encrustation, migration (especially in single-ended models), UTIs and persistent haematuria. Others have noted similar issues but typically have reported lower rates of complications leading to stent removal (Abdill et al. 1994, Chancellor et al. 1995, Seoane-Rodriguez et al. 2007; Abdul-Rahman et al. 2010). Despite these issues, when the stents are in place they appear to be effective, resulting in significant reductions in voiding pressure and post-void residual urine volumes although no significant changes have been noted in bladder capacity (Chancellor et al.1993b; Abdill et al. 1994; Chancellor et al. 1995; Seoane-Rodriguez et al. 2007; Abdul-Rahman et al. 2010). In addition, reduced incidence of UTIs and autonomic dysreflexia has typically been reported (Chancellor et al.1993c; Seoane-Rodriguez et al. 2007). Game et al. (2008) advocate for a trial period with a temporary stent early post-injury based on the percentage of patients (~30%) not choosing placement of a permanent stent or in whom the stent did not provide the expected results. This reversible management option is however, limited by the available materials for temporary stenting. Rivas et al. (1994) reported a clear patient bias in favour of the stent because of its short- and long-term reversibility. The authors also concluded that the stent was equivacol to external sphincterotomy in terms of urodynamic values and superior for reasons of reduced surgery, hospitalization, costs and hemorrhage as an adverse event.
Chancellor and colleagues (1999) also conducted a RCT (n=57) comparing the outcomes associated with sphincterotomy as compared to placement of the stent (UroLome) prosthesis. This study was deemed a low quality RCT, largely because blinding and concealed allocation was not possible given the nature of the intervention. Similar measurement procedures and overall findings were noted as reported for the studies above (i.e., Chancellor et al. 1993c) with significant decreases in voiding detrusor pressure and post-void residual urine volumes and no significant changes reported for bladder capacity and no differences noted between sphincterotomy and stent for any measure at any time point (i.e., 3, 6, 12 and 24 months). The need for catheterization, initially required in 50% of the sphincterotomy group (n=26) and 71% of the stent group (n=31), was reduced to no more than four individuals at all follow-up timepoints for both groups. There was little difference in subjective assessment of impact of bladder function on QoL or in the incidence of complications between the treatment groups although those in the stent group spent less time in the hospital for the procedure.
Chancellor et al. (1993b) also have examined another procedure with similar rationale as that associated with sphincterotomy. This investigation involved a pre-post trial design (n=17) of transurethral balloon dilation of the external urinary sphincter. Again, similar methods were employed as the studies noted above and findings were also similar. Of all 17 patients previously managed by indwelling Foley catheter, 15 used condom catheters post-procedure and two voided on their own. Significant decreases were noted in voiding pressure (p=0.008) at all follow-up times (i.e., 3, 6 and 12 months). No changes were observed in bladder capacity (p=0.30); significant reductions in post-void residual urine volumes (p<0.05) were observed at all follow-up times. Positive urine cultures (i.e., UTI) were noted in 15 of 17 subjects prior to surgery but only in 5, 8 and 4 patients at 3, 6 and 12 months, respectively. Subjective autonomic dysreflexia improved in all nine individuals who had previously experienced AD.
More recently, Patki et al. (2006) reported a small retrospective case series investigation (n=9) of an implantation of an artificial urinary sphincter (AUS; American Medical System 800). This device has evolved over the years to where it is now easier to implant surgically, has a longer life and a higher success rate in achieving incontinence (~80% with more recent models). In this trial, all patients achieved successful incontinence with no self-reported leakage upon activation of the system. However, by 3-month follow-up, two patients reported significant recurrrent incontinence, with one implant being removed and the other being revised; by a mean follow-up of 105.2 months, 5 of 9 implants had been successful with no revisions. Overall, more than half of the patients with working implants recorded higher maximum detrusor pressures although no upper tract change or deterioration in renal function was noted in any patient. A retrospective analysis in 2009 by Bersch et al. of individuals (n=51) who underwent implantation of an artificial sphincter at the bladder neck using a port instead of a pump suggested this approach to be highly successful, reliable, safe and a cost-effective treatment option (even with implant revisions). Additionally, a retrospective review by Chartier-Kastler et al. (2011) determined an artificial urinary sphincter device was effective in restoring urinary continence in males, in the majority of cases reviewed, with a decrease in urethral erosion by placement of the device around the bladder neck, providing more credence to consideration for SCI patients.
Based on the success of safety and efficacy of tension-free vaginal tape for stress incontinence in feamles with neuropathic bladders (N=12; NSCI=3), Hamid et al. 2003 concluded that tension-free vaginal tape was safe for the treatment of women with neuropathic intrinsic sphincter deficiency. Pannek et al. (2012), with the promise of the work of Hamid et al. (2003) and a long history of success in improving continence for women with non-neurogenic stress incontinence, sought to evaluate the use of transobturator tape for women suffering from stress incontinence of neurogenic origin secondary to SCI. Even by eliminating sources of variability for success such as material type and surgical competence, the results of this case series (n=9) yielded unfavourable results. Low cough or valsalva induced leak point pressure incontinence and high complication rates of the procedure led the authors to conclude that the transobturator tape was not a viable option for the treatment of SCI related neurogenic stress incontinence. Other attributions to the interventional failure in this patient population were thought to be related to the specific type and grade of detrusor deficiency and the prevalence of pelvic deformity development (Hobson & Tooms 1992) such as a posteriorly tilted pelvis that would interfere with the position of the obturator foramen.
Conclusion
There is level 4 evidence (from one case series study: Perkash 2007) that sphincterotomy is effective in reducing episodes of autonomic dysreflexia associated with inadequate voiding.
There is level 4 evidence (from one case series study: Pan et al. 2009) that sphincterotomy, as a staged intervention, can provide long-term satisfactory bladder function.
There is level 2 evidence (from a one RCT and several level 4 studies: Chancellor et al. 1999) that both sphincterotomy and implantation of a sphincteric stent are effective in reducing incontinence, with little need for subsequent catheterization, and both treatments are associated with reduced detrusor pressure and reduced post-void residual volume but not with changes in bladder capacity. The only significant difference in these two treatments was the reduced initial hospitalization associated with the stent, given the lesser degree of invasiveness.
There is level 4 evidence (from one pre-post study and one case series study: Chancellor et al. 1993c; Seoane-Rodriguez et al. 2007) that implantation of a sphincteric stent may result in reduced incidence of UTIs and bladder-related autonomic dysreflexia over the short-term although several studies have demonstrated the potential for various complications and subsequent need for re-insertion or another approach over the long-term.
There is level 4 evidence (from one pre-post studroy: Juma et al. 1995) that over the long-term, previous sphincterotomy may contribute to a high incidence of various upper and lower tract urological complications.
There is level 4 evidence (from one case series study: Game et al. 2008) that advocates for placement of a temporary stent early after injury as a reversible option that allows patients to choose from the range of permanent stent placement to less invasive bladder management methods such as intermittent catheterization.
There is level 4 evidence (from one pre-post study: Chancellor et al. 1993b) that transurethral balloon dilation of the external sphincter may permit removal of indwelling catheters in place of condom drainage, and also may result in reduced detrusor pressure and post-void residual volume but not with changes in bladder capacity.
There is level 4 evidence (from one case series study and one pre-post study: Patki et al. 2006; Bersch et al. 2009) that implantation of an artificial urinary sphincter may be useful in the treatment of incontinence in SCI but further study is required.
There is level 4 evidence (from one pre-post study: Ke & Kuo 2010) that transurethral incision of the bladder neck may be useful in bladder neck and voiding dysfunction.
There is level 4 evidence (from one case series study: Pannek et al. 2012) that transobturator tape implantation is not effective in managing neurogenic stress incontinence in females living with SCI.
