**5. Preoperative risk factors for mixed urinary incontinence**

Though various factors have been described in the literature to predict the persistence of urge components following incontinence procedures, no single predictor has presented consistent value between studies. Earlier studies, investigating Burch colposuspension, suggested precedence in patient symptom history were indicative of symptom predominance within a mixed profile of incontinence, and consequently better outcomes for patients with precedent stress symtoms. Scotti et al. investigated 82 women who underwent Burch colposuspension. (Scotti et al., 1998) They found that patients with a history of stress symptoms preceding the onset of urge symptoms showed higher cure rates compared to antecedent urge patients (78.6% vs 22.2%, p<0.001). Langer et al. also showed similar results, also with Burch colposuspension. However, these results have not been reproduced in recent MUS procedures. (Langer, 1988)

Urodynamic studies would appear to have predictive benefit for some patients with mixed symptoms in elucidating the gravity of urethral dysfunction (stress component) and any associated detrusor dysfunction. (Lin et al., 2004) Certain aspects of detrusor dysfunction, such as high-pressure detrusor overactivity, have been suggested to be indicative of outcome, though investigators varied in their use of its reference value. The authors retrospectively reviewed 279 patients with MUI who underwent MUS with at least 2 years of follow up. (Kim et al., 2008) Patients were divided into patient with a predominance of bother symptoms and a predominance of DO, where DO patients were further divided into patients with high pressure DO and low pressure DO with a reference level of 15cmH2O of maximum detrusor pressure at which involuntary contraction occurs during filling cystometry. We found that patients with high pressure DO showed improvement of urge symptoms in 70% compared to 91.4% for patient with low pressure DO (p=0.03). These factors also seemed to affect resolution of stress components as patients with high pressure DO showed lower resolution rates than low pressure DO patients (90% vs. 96.6%, p=0.04). In a retrospective study of 51 patients, Panayi et al. found that higher opening detrusor pressure, lower volume at DO during cystometry and higher detrusor pressure were predictive of persistent DO. (Panayi et al., 2009) Schrepferman et al. evaluated 84 women undergoing a pubovaginal sling surgery for MUI. (Schrepferman et al., 2000) Of those patients, 69 had urgency symptoms. Urgency was related to defined motor urge (as established on urodynamic testing) in 41 women. Twenty-eight patients experienced sensory urgency (urge symptoms with/ without urodynamic findings). Complete resolution

Preoperative Factors as Predictors of Outcome

associated with mixed symptoms.

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pp. (372-375), ISSN 1520-6777

**7. References** 

of Midurethral Sling in Women with Mixed Urinary Incontinence 215

and urgency symptoms represent a separate and distinct pathophysiology, of which the possible occurrence or persistence must be addressed before management of stress incontinence symptoms. Several studies have suggested high pressure detrusor overactivity or maximal urethral pressure during preoperative urodynamic studies may implicate a higher rate of treatment failure in mixed urinary incontinence. Other studies have suggested insights into the predominance or antecedence in urgency symptoms may be indicative of treatment difficulty. Currently, no definite conclusions have been reached. Future studies require a cohesive approach in determining risks and treatment methods, while clinically, patients should be warned of risks and possibility of continued medical treatment

Anger, J. T. & Rodriguez, L. V. (2004). Mixed incontinence: stressing about urge. *Current* 

Ankardal, M., Heiwall, B., Lausten Thomsen, N., Carnelid, J. & Milsom, I. (2006). Short and

Awad, S. A. & McGinnis, R. H. (1983) Factors that influence the incidence of detrusor

Bump, R. (1993). Racial comparisons and contrasts in urinary incontinence and pelvic organ prolapse. *Obstetrics and Gynecology*, Vol. 81, No.3, pp. (421-425), ISSN 0029-7844 Bump, R., Norton, P., Zinner, N. & Yalcin, I. (2003). Duloxetine Urinary Incontinence Study

Chaliha, C. & Khullar, V. (2004). Mixed incontinence. *Urology*, Vol. 63, No.3, pp. (51-57),

Choo, M. S., Ku, J. H., Oh, S. J, Lee, K. S., Paick, J. S., Seo, J. T., Kim, D. Y., Lee, J. J., Lee, J.G.,

*Pelvic Floor Dysfunction*, Vol. 18, No. 18, pp. (1309-1315), ISSN 0937-3462 Chou, E. C. L., Blaivas, J. G., Chou, L. W., Flisser, A. J. & Panagopoulos, G. (2008).

Colombo, M., Zanetta, G., Vitobello, D. & Milani, R. (1996). The Burch colposuspension for

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or improvement in urge symptoms occurred in 24 (58.5%) patients with urodynamically demonstrated motor urge incontinence, and an additional 7 (17.1%) patients were improved. In those patients with sensory urgency, only 11 (39.3%) patients were cured, and 9 (32.1%) patients were improved. Additionally, in those patients with urodynamic motor urge overactivity, 21 of 23 (91.3%) patients were cured, and 2 (8.7%) patients were improved if low pressure overactivity was present. High-pressure instability was associated with a cure in only 5 (27.8%) patients, and improvement in another 5 (27.8%) patients. The investigators used 15 cm of water as a cutoff for low-pressure versus high-pressure motor overactivity of the bladder. They suggested that patients with low-pressure motor urgency are more likely to experience resolution than those with high-pressure. Despite the fact that the International Continence Society no longer utilizes motor versus sensory urgency, the application of this trial is limited; however, these findings are interesting and provocative for potential subsequent clinical trials. Finally, on the basis of the symptoms present, Scotti et al. reported that high-pressure detrusor overactivity presented commonly with stress symptoms is a significantly poor prognostic indicator with pressures of 25cmH2O or greater being consistent with poor surgical results. (Scotti et al., 1998)

Recently, Paick et al. evaluated factors that might predict persistency of urge incontinence in patients after undergoing tension-free vaginal tape (TVT) procedures. (Paick et al., 2007) They evaluated 274 patients of which 73 had mixed urinary symptoms. They found cure rates for stress incontinence to be different (78.1% for the mixed symptom group versus 95.5% for the pure group). Their analysis revealed that maximal urethral pressure was associated with a greater risk of persistent urge symptoms, suggesting that profound urethral dysfunction may be contributory to persistent symptoms after TVT. These findings are again intriguing and suggest the possibility that urethral dysfunction and resultant effects upon the severity of SUI may affect detrusor function. This paper gives further support to the fact that correction of the low-pressure outlet may benefit at least some individuals with detrusor overactivity although the overall benefit may be less than that experienced by patients with only SUI.

Other studies have failed to find significant predictive value for successful treatment of MUI in urodynamic studies. Houwert et al. retrospectively reviewed 437 patients who received MUS, in which the diagnosis of MUI itself was also used as a factor in analysis. (Houwert et al., 2009) Results showed that a diagnosis of MUI, a history of previous incontinence surgery and the presence of detrusor overactivity was predictive, while urodynamic parameters failed to suggest insight to outcomes in multivariate analyses. However, relative symptom components are most frequently reported as predominant and nonpredominant (assuming a rough estimate of percentage contribution). As noted previously, this method can be inaccurate and begs the need for better methods of symptom quantification. Given the confusing terminology for both patients and surgeons of what constitutes MUI, as well as the higher failure rate of surgical outcomes, treatment should be individualized based on clinical scenario along with urodynamic findings.

#### **6. Conclusion**

Recent advances in surgical treatment for stress urinary incontinence have provided effective resolution with limited morbidity. However, preoperative components of urgency complicate the treatment outcomes in a significant number of patients. Detrusor overactivity and urgency symptoms represent a separate and distinct pathophysiology, of which the possible occurrence or persistence must be addressed before management of stress incontinence symptoms. Several studies have suggested high pressure detrusor overactivity or maximal urethral pressure during preoperative urodynamic studies may implicate a higher rate of treatment failure in mixed urinary incontinence. Other studies have suggested insights into the predominance or antecedence in urgency symptoms may be indicative of treatment difficulty. Currently, no definite conclusions have been reached. Future studies require a cohesive approach in determining risks and treatment methods, while clinically, patients should be warned of risks and possibility of continued medical treatment associated with mixed symptoms.
