Use of Bowel in Undiversion

A new, unique and simple method for ureteral implantation in kidney recipients with small, defunctionalized bladders

BACKGROUND

Major, almost insurmountable, deterrents exist to the use of the small capacity, defunctionalized, nonneurogenic urinary bladder in renal transplantation, namely, the technical difficulty in performing a satisfactory ureteral implantation with conventional methods and the potential secondary problems with high grade ureteral reflux and obstruction. Alternatives are less than ideal and include transplantation into a bowel-augmented urinary bladder with intermittent self-catheterization, ileal conduit urinary diversion, or avoidance of transplantation and relegating the patient to life-long dialysis.

METHODS

Eight consecutive patients (ages 13 months to 29 years) with small, defunctionalized urinary bladders underwent a new method of intravesical implantation of the transplant ureter. The mean capacity of these bladders was 18.5+/-13.1 ml (range 6 to 45 ml), with the bladders defunctionalized for a mean 81.6+/-24.3% of the patients' total lifetime. The technique involved placement of the transplant ureter into a shallow, mucosa-denuded, rectangular trough extending from a superiorly placed ureteral hiatus distally to the trigone. We hypothesized that the mucosal margins on the two lateral aspects of the rectangular trough would grow over the anterior surface of the ureter until they met the advancing mucosal edges from the contralateral side to form a natural neosubmucosal tunnel.

RESULTS

Posttransplantation cystoscopic examination demonstrated bladder mucosal regeneration and growth over the ureter, confirming the spontaneous development of a good length neosubmucosal tunnel. All patients demonstrated no evidence of ureteral reflux or ureteral obstruction, whereas an immediate prior cohort of four consecutive patients with bladder capacities < or =30 ml showed that three of four had ureteral reflux (P=0.02) and four of four developed hydronephrosis (P=0.002). All urinary bladders in the present cohort enlarged to expected normal or nearnormal capacities. Serum creatinines were stable throughout the entire follow-up period, with the exception of one patient who had rejection episodes. Two patients had urinary tract infections posttransplantation, but there were no episodes of acute pyelonephritis.

CONCLUSIONS

This novel technique for ureteral implantation successfully capitalizes on the regenerative potential of the bladder mucosa, resulting in a physiological, anatomically natural, and very effective neosubmucosal tunnel. It appears to guarantee success against both ureteral reflux and obstruction, no matter how small the urinary bladder, and offers no hindrance to enlarging the bladder to near normal capacity posttransplantation. The implantation technique is simple and safe, and its use should eliminate the reluctance to use these bladders. Moreover, this procedure offers a major incentive for the successful rehabilitation of small, defunctionalized, nonneurogenic bladders after kidney transplantation.

Bladder augmentation. Options, outcomes, future

Remarkable progress has been made in lower urinary tract reconstruction in children. Nowhere is this more valuable than in augmentation cystoplasty, where there are several available options. This article discusses the current techniques and the benefits and limitations of these procedures. A section on tissue regeneration techniques and the author's current recommendations are included.

Augmenting the augmented bladder: treatment of the contractile bowel segment

PURPOSE

Bowel used for bladder reconstruction regardless of detubularization occasionally retains its contractile properties. Of 323 patients who underwent primary enterocystoplasty we identified 19 who continue to have high pressure bladder contractions and required augmentation of the previously augmented bladder.

MATERIALS AND METHODS

Reason for repeat augmentation, upper tract changes, original and secondary bowel segments used, and urodynamic findings were evaluated in all patients. Current status and followup also were noted.

RESULTS

After initial augmentation 8 patients had persistent incontinence, 5 bladder perforation, 3 isolated upper tract changes, 2 incontinence and bladder perforation, and 1 incontinence plus intractable pain. Preoperative urodynamics revealed detrusor pressures from 30 to 100 cm. water. All patients had adequate bladder outlet resistance. The original bowel segments used were sigmoid in 12 cases, stomach in 4, ileum in 2 and cecum in 1. Bowel segments for re-augmentation were ileum in 16 cases and sigmoid in 3. Of the 11 patients with incontinence 10 are now dry. All cases of upper tract changes resolved. Mean followup since re-augmentation is 52 months.

CONCLUSIONS

If the outcome of bladder augmentation is less than optimal, it is important to reevaluate the bladder dynamics. In rare instances these patients may continue to have high pressure contractions with a functionally small bladder capacity. In such situations reaugmentation with an additional bowel segment is an excellent alternative to a difficult clinical problem and provides good results in the vast majority of cases. This treatment may not totally alleviate the contractions but it does decrease them and increase the volumes at which the contractions occur, making them no longer clinically or functionally significant.

Use of the appendix in reconstructive surgery: a case against incidental appendicectomy

Ignored for years, the appendix is once again being promoted as having useful surgical potential, notably in the management of incontinence. Incidental and prophylactic appendicectomy with their established complications become less easy to justify as the incidence of appendicitis declines. The role of the appendix in reconstructive surgery is reviewed, with particular reference to urinary reconstruction and to the treatment of chronically constipated or faecally incontinent children by use of the antegrade continence enema.

Bladder replacement after radical cystectomy using detubularized right colonic segment

Bladder replacement after radical cystectomy offers the cancer patient the possibility of restoration to a functional level not possible with the standard means of urinary diversion. Herein we present our experience using a detubularized right colonic segment to create functional reservoirs in 2 male patients and a continent reservoir in a female patient. Cystometric analysis reveals capacious reservoirs, low basal pressures, and a tendency toward pressure spikes at higher filling volumes. All 3 patients are continent at volumes up to 400 cc with preservation of the upper urinary tracts and the absence of reflux. We believe the simplicity of this technique and the encouraging results will contribute to more widespread application of continent and functional reservoirs.

Selection of intestinal segments for bladder substitution: physical and physiological characteristics

Detubularized bowel segments provide greater capacity at lower pressure and require a shorter length of intestine than do intact segments. Four factors account for their superiority: 1) their configuration takes advantage of the geometric fact that volume increases by the square of the radius so that a patch or pouch has a larger diameter than a tube, 2) they accommodate to filling more readily because, as LaPlace's law states, the container with the greater radius and, thus, the greater mural tension will hold larger volumes at lower pressure, 3) compliance is superior to that of the tubular bowel and 4) contractile ability is blunted by the failure of contractions to encompass the entire circumference. For these reasons detubularized segments store more urine at lower pressures.

Pediatric urinary diversion and undiversion

Many things have changed in our management of the urinary tract of children and young adults. Important contributions from many sources have resulted in the refinement of therapy and the progression from diversion to undiversion and reconstruction. Primary urinary diversion is now uncommon. Patients with exstrophy, for example, are treated with primary bladder closure as newborns, and newborns with valves often are treated with primary valve ablation. Children with neurogenic bladder dysfunction resulting from myelodysplasia are rarely diverted, but are started at an early age with ICC. It is hoped that in future the contents of this article on diversion techniques and undiversion will be of historical interest, however. Note: The editors also have found the use of the Mitrofanoff procedure, utilizing a nonrefluxing tunnel and a catheterizable stoma made out of the ureter or appendix, to be a very valuable addition to the reconstructive surgeon's armamentarium. We also feel that use of detubularized bowel for either bladder augmentation or replacement provides more efficient storage capability. Occasional reports of extremely significant diarrhea after removal of the ileocecal segment from the intestinal tract have been reported in children with myelodysplasia.

An operation to create a continent catheterizable urinary sphincter from a short intestinal segment: experimental observations

We describe a new operation to create a continent, catheterizable urinary sphincter from a short segment of ileum. The sphincter has provided continence over a wide range of bladder pressures in dogs and it may be adapted to a variety of clinical continence requirements.