A prospective, randomized trial of retropubic versus transobturator slings (the TOMUS trial) involving 597 patients revealed more bladder perforations in the retropubic group (15 vs. 0), more patients with elevated PVR volume (>100 mL at time of discharge), and higher rate of sling release or catheterization for voiding dysfunction after 6 weeks (8 vs. 0). The transobturator group had more vaginal perforations (13 vs. 6) and neurologic symptoms including lower extremity weakness and numbness found immediately following surgery to 6 weeks (31 vs. 15). Otherwise, serious adverse events were similar in both groups (108).
Erosion is unique to surgeries in which a graft is placed, and the rate depends largely on the type of graft used. Tension-free vaginal tape is associated with a low rate of graft erosion, compared with a much higher rate of erosion with certain synthetics previously used for pubovaginal slings. Most midurethral synthetic slings used at this time are made of polypropylene; the main differences in the character of the mesh involve elasticity and rigidity and not the material itself.
In the randomized trial comparing TVT to TOT described above, of the 597 women who underwent a sling procedure, 1.8% of the patients were noted to have a mesh erosion or exposure (108).
The most common adverse events (5% to 10% rate for each) after all surgeries for stress urinary incontinence include urinary tract infection, failure to cure, new onset detrusor overactivity, voiding dysfunction, genital prolapse, and bladder perforation. When new onset detrusor overactivity occurs after surgery for incontinence, cystoscopy should be considered to rule out a foreign body in the bladder (Fig. 26.13). Less common events (2% to 5% for each) include excessive blood loss, wound infection, pain, or nerve injury. Events such as sinus tracts and fistulae are rare. Erosion rates depend on the material implanted and, as noted previously, are rare for the midurethral slings. In addition, medical events, such as thromboembolic, cardiac, or pulmonary events, are rare.
As midurethral slings largely replace pubovaginal slings and retropubic urethropexies as the primary procedure for stress urinary incontinence, the comparison of complications of these procedures becomes more important. Given the debate on the effectiveness of the different approaches for midurethral slings, the severity and incidence of complications for midurethral slings will become more important when determining the best primary procedure for stress urinary incontinence. Likewise, the uncommon occurrence of intraoperative and long-term complications of these procedures and underreporting of complications demonstrates the need for reliable large registries for midurethral slings and other promising procedures to assess the safety of these procedures.
Figure 26.13 Cystoscopic view of encrusted suture penetrating bladder wall following sling urethropexy.
Neuromodulation Even with the development of newer anticholinergic medications with fewer side effects, there continues to be a select group of patients with overactive bladders who remain refractory to standard medical and behavioral treatment. Surgical treatment of this condition traditionally involved substantial morbidity and major urinary denervation, reconstruction, or both to achieve therapeutic benefits. The development of implantable sacral nerve root stimulators led to FDA approval of sacral root neuromodulation in patients with refractory urinary urgency and frequency, urge incontinence, and voiding dysfunction. This therapy offers patients with severe symptoms an alternative to urinary augmentation or diversion. Sacral nerve stimulation therapy is performed in two phases. In the first phase, a percutaneous nerve evaluation test is performed to determine which patients respond to this type of therapy. Those who respond are implanted with a permanent electrode lead adjacent to the third sacral nerve root connected to a pulse generator.