Urodynamic findings in patients with urogenital fistulae

To assess the feasibility of carrying out a urodynamic investigation in patients with a urogenital fistula and to establish the incidence of abnormal lower urinary tract function in such patients.

Of 38 patients referred within the last 3 years with a diagnosis of lower urinary tract genital fistula, 30 were investigated by dual-channel subtracted cystometry before surgical treatment of their fistula; in addition, urethral pressure profilometry was carried out in 19 patients. Fourteen of the patients had fistulae into the vaginal vault; the urodynamic findings in this subgroup were compared with those of 12 patients with bladder neck and urethrovaginal fistulae. Twenty-six of the 30 patients underwent surgical treatment and 24 (92%) were cured anatomically by their first procedure. Ten patients complained of residual lower urinary tract symptoms and were re-investigated.

Of the 38 patients, 47% had genuine stress incontinence, 40% showed systolic detrusor instability and 17% impaired bladder compliance. Half had evidence of voiding dysfunction; most appeared to be of a hypotonic detrusor type, although four cases showed an obstructive pattern. Fifteen patients had more than one abnormality and only five (17%) had entirely normal urodynamic findings. The overall incidence of functional abnormality was highest in the patients with urethral or bladder neck fistulae, with only one showing entirely normal urodynamic findings. Genuine stress incontinence was found more than twice as often associated with urethral or bladder neck fistulae and detrusor instability was also more common in this group. Voiding dysfunction of both hypotonic and obstructive types was found equally in the two groups. After surgical treatment, most patients became continent and free from lower urinary tract symptoms, although one complained of residual stress incontinence and nine of urgency or urge incontinence. Of the latter, six were found to have detrusor instability, one after repair of vault fistula, three after urethral or bladder neck fistulae and the other two after mid-vaginal fistulae.

There is a high incidence of abnormal lower urinary tract function in patients with urogenital fistulae. Patients with urethral or bladder neck fistulae had a higher incidence of both detrusor instability and genuine stress incontinence than those with fistulae into the vaginal vault. Many of these abnormalities appear to resolve after successful repair of the fistula, although detrusor instability may persist and require further treatment in some women. These findings are relevant to the counselling of patients before repair and may be of medico-legal significance.