Is there a role for periurethral collagen injection in the management of urodynamically proven mixed urinary incontinence?

Objectives: To investigate the effectiveness of periurethral collagen injection (PCI) in patients presenting with symptoms of mixed urinary incontinence (MUI) and urodynamically demonstrated sphincter deficiency and detrusor overactivity. Methods: A retrospective review was performed on all patients undergoing PCI from February 1999 to February 2003, during which those with MUI were treated with PCI as first-line therapy. The inclusion criteria were MUI symptoms, detrusor overactivity on urodynamic study, stress urinary incontinence due to sphincter deficiency (determined from physical examination, stress test, urodynamic study with Valsalva leak point pressure, and cystography findings, without urethral hypermobility). The primary outcome measures were the Urogenital Distress Inventory (UDI), Incontinence Impact Questionnaire, and quality-of-life score and the need for anticholinergic medications or additional surgery. Comparisons were performed using the Wilcoxon signed ranks test and paired t test. Results: Of the 56 patients who underwent PCI, 43 presented with symptoms of MUI, and 16 of these (29%) had both detrusor overactivity and stress urinary incontinence on urodynamic study. The mean follow-up after PCI (without additional PCI) was 18 months (range 6 to 39). The mean age was 65 years (range 40 to 84). The mean Valsalva leak point pressure was 54 ± 40 cm H₂O (range 18 to 146). Ten patients had undergone previous anti-incontinence procedures, and anticholinergic medications had failed in six. The questionnaire scores, indicating severe MUI/poor quality of life before PCI, improved after PCI: UDI question 1, 2.3 ± 0.8 versus 1.3 ± 1.0 (P = 0.021); UDI question 2, 2.1 ± 1.2 versus 1.4 ± 1.0 (P = 0.068); UDI question 3, 2.9 ± 0.4 versus 1.8 ± 1.2 (P = 0.010); and quality-of-life question, 8.6 ± 2.1 versus 5.2 ± 3.5 (P = 0.026). The mean injected volume/patient was 8.5 cm³ (range 5 to 17) within a mean of 1.9 treatments (range 1 to 3). Four patients continued taking anticholinergic medications and one proceeded to sling placement. Conclusions: The use of PCI as the primary/initial intervention in patients with MUI may be the preferred approach, particularly in patients with an elevated risk of anticholinergic medication side effects or when voiding dynamics preclude sling placement.