Can the effect of adhesion barriers and/or intravesical balloon inflation improve bladder autoaugmentation outcomes in a rabbit model?

INTRODUCTION

Bladder augmentation is used for the treatment of bladder dysfunction in order to minimize intravesical pressure and increase bladder capacity. However, less-invasive procedures, such as autoaugmentation, have been proposed due to several complications that have occurred using bowel and gastric segments. The technique of autoaugmentation involves wide excision of the detrusor by leaving the bladder mucosa intact and has shown increased bladder capacity and compliance. An additional step to keep the achieved surface area of this non-contractible bladder segment and, thus, bladder capacity, was reported by using an intravesical balloon to prevent shrinkage of the surgically achieved diverticulum during autoaugmentation. On the other hand, adhesion barriers (AB) with absorbable hydrogel, which can spare tissue and organ plans, are used to prevent postsurgical adhesions. The efficacy of sprayable AB has been demonstrated in animal models and it is now mostly used in laparoscopic surgeries.

OBJECTIVE

The present study aimed to compare the efficacy of AB and/or intravesical balloon insertion, which might potentially improve the urodynamic and histopathological outcomes of autoaugmentation in a rabbit model.

METHODS

A total of 25 New Zealand rabbits were included in the study. Following the surgical reduction to form a low-capacity bladder model (35-40% of the initial volume), standard detrusorotomy was performed in all groups except the sham group. Group 2 had only autoaugmentation as the control group. The bladders in Group 3 were supported with an intravesical balloon. An Adhesion Barrier System (CUI Tissue Expander) was used for all bladders in Group 4, without balloon inflation. In Group 5, both intravesical balloon inflation and adhesion barrier application were performed following autoaugmentation. Urodynamic evaluations were performed at day 0 before reduction, day 0 after reduction, and the 90th postoperative day. Capacity and compliance measurements were noted. Bladders were histopathologically evaluated. Expression of CD31 (microvessel density) and fibrosis were noted.

RESULTS

Autoaugmentation does not result in a reliable increase in bladder capacity and compliance when compared to a sham group. Urodynamic measurements were similar in balloon-inflated groups (Group 3 and Group 5), showing a statistically significant improvement. Sprayable AB system alone revealed a slight, but not statistically significant, increase (Table). No significant differences between all five groups were detected regarding microvessel density (CD31 expression) and fibrosis.

DISCUSSION

In the present study, the intravesical balloon application (IVBA) efficiency was investigated alone and in combination with AB. The main basis of this study were the previous findings, which demonstrated prevention or decrease in the contraction of diverticula by IVBA. The role of AB alone or within a combination was also evaluated. Adhesion barriers are mostly used in laparoscopic gynecologic and colorectal operations. They decrease the postoperative adhesions by forming a physical barrier. In the present study, it was thought that AB might reduce postoperative adhesions and enhance the outcome of autoaugmentation. One of the most important outcomes was the inconsistency of fibrosis density with final bladder capacity and compliance values; this finding did not support the role of fibrosis prevention with IVBA. The present study had some limitations: the partial cystectomy method, which was used to form a low-compliance bladder, is a different clinical condition to neurogenic bladder, and a rectal catheter was not used during urodynamic evaluation. General anesthesia and muscle relaxant were performed during urodynamy and abdominal contractions were not seen.

CONCLUSION

Bladder autoaugmentation in a rabbit model, followed by intravesical balloon inflation offers improvement in bladder capacity and compliance. The use of sprayable adhesion barrier hydrogel technology may facilitate tissue healing and result in it being easier to maintain the success achieved by surgery when only supported with an intravesical balloon.