The use of the appendix as a continent catheterizable stoma

We review the results of 5 years of using the unmodified appendix for reconstruction of neobladders and native bladders, and describe the mechanism of continence.

Between 1993 and 1997, 24 patients have undergone continent urinary diversion using the unaltered appendix. Median patient age at the time of surgery was 62 years. Patients were followed at the urological outpatient clinic for a mean of 18 months (range 7 to 47). Video urodynamic studies were performed once in the first 6 months postoperatively and repeated if there was any history of incontinence or bladder problems.

Of the patients with an appendicovesicostomy onto the native bladder 80% were dry during the day and night. This figure was improved to 94% when 2 patients with incontinence catheterized more frequently. Patients with a neobladder were more likely to be continent and had a longer interval between catheterizations, which reflects the larger reservoir volume rather than better continence mechanism in these patients. The level of continence is at the appendiceal bladder junction in the native bladder and the appendicocecal junction in the neobladder, which is able to withstand reservoir pressures of 30 to 40 cm. water. Stress incontinence driven by abdominal pressure did not occur. Instead incontinence occurred when the bladder became over full and the pressure increased, or during an unstable contraction.

The appendix does not need to be tunneled through the bladder wall to achieve satisfactory continence. In a low pressure reservoir continence may be achieved simply by anastomosing the appendix directly onto the bladder or leaving it in situ when creating a neobladder.