Alternative Procedure Called Safer, Effective for Neurogenic Bladder

June 03, 2013

NEW YORK (Reuters Health) Jun 03 - Bladder auto-augmentation by detrusor myotomy is a good alternative to enterocystoplasty for children with neurogenic bladder dysfunction, clinicians from Denmark say.

In their experience, it can provide a long lasting increase in bladder capacity, better bladder compliance and a lowering of detrusor pressure. It's also safe, doesn't have the potential complications connected to enterocystoplasty, and doesn't preclude future enterocystoplasty or other surgical procedures if needed, they say.

In a paper online May 24th in the Journal of Urology, Dr. Eva Lund Hansen and colleagues from Aarhus University Hospital Skejby describe long-term outcomes for 25 children younger than 16 years with NBD who underwent auto-augmentation by detrusor myotomy between 1992 and 2008.

They all had poorly compliant bladders, high detrusor pressure and small maximal bladder capacity, which "may cause irreversible kidney damage over time," the researchers note.

Twenty-two patients had spinal dysraphism (myelomeningocele), two had congenital partial agenesis of the sacrum, and one had congenital scoliosis. All had small bladder capacity, low compliance and high end-filling pressures and were unresponsive or only partially responsive to clean intermittent catheterization and anticholinergic therapy.

Twenty-one patients were incontinent, four had recurrent urinary tract infections (UTIs), nine had vesicoureteral reflux (VUR), six had hydronephrosis and two had chronic renal failure.

Detrusor myotomy was combined with bladder neck sling in nine patients; 10 patients received a continent vesicostomy (Mitrofanoff) and five of the nine cases with VUR had ureteral reimplantation combined with the detrusor myotomy. The sling procedure was performed in patients with low leak point pressures.

The 25 children (12 boys, 13 girls) were followed for up to 16 years (median, 6.8 years). Median bladder capacity before bladder auto-augmentation was 103 mL. Five months after surgery, it had increased significantly to 176 mL (p<0.01). "This increment remained significant during the rest of follow-up," the researchers say.

In addition, bladder compliance doubled after one year to 10 mL/cm H2O (p<0.05) compared to the preoperative level, and further increase was seen after five years to 17 mL/cm H2O (p<0.05). Median maximal detrusor pressure was 43 cm H2O preoperatively and decreased significantly (p<0.01) after surgery. It was 26 cm H2O at the final follow-up.

"These findings were permanent in 92% of the patients after more than 10 years," the investigators say, and 18 of 25 patients became continent.

Detrusor myotomy was safe, with no major peri- or postoperative complications associated with detrusor myotomy in 24 cases. Kidney function developed normally in all cases except in one patient with persistent uremia. VUR was alleviated in seven of nine cases and downgraded in one.

The investigators say the operative technique and the immediate postoperative care seem to be important in the development of an acceptable bladder capacity.

To prevent shrinkage and scarring, patients start a strict regimen of bladder cycling right after surgery. "It is our premise that early active bladder cycling is important for the development of increased bladder volume post auto-augmentation and that its omission will affect outcomes adversely," they write.

This, coupled with the operative technique (fixation of the anterior and posterior detrusor flaps and the deep incision of the detrusor) are the main contributors to the positive results achieved, they say.

"It is our assessment that hitching the detrusor to the rectus and retroperitoneum prevents closure of the myotomy and hence precludes shrinkage," the authors wrote. "Besides the hitching, we make sure to extend the incision of the detrusor all the way from the bladder dome down to the proximity of the ureter on both sides of the bladder."

"Since auto-augmentation was introduced by Cartwright and Snow in 1989, there has been an ongoing debate concerning the advantages and disadvantages of this procedure compared to gastrocystoplasty or enterocystoplasty," Dr. Hansen and colleagues point out in their paper.

The disadvantages of enterocystoplasty, they add, include "a multitude of metabolic disorders, resulting from the intestinal segments native function of secretion and reabsorption," along with risks for bladder perforation, mucus production, stone formation and neoplasia.

"Enterocystoplasty constitutes a major intraperitoneal procedure associated with various potential complications, and patients often need prolonged convalescence," the researchers warn. "Moreover, patients are consigned to life-long invasive follow-up protocols."

On the other hand, "auto-augmentation has the advantage of being a relatively simple extraperitoneal procedure to perform and it does not preclude other methods of bladder augmentations in case of failure."

The authors did not respond to request for comment on their paper.


J Urol 2013.


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