Combined Buccal and Lingual Mucosa Grafts for Urethroplasty: An Experimental Study in Dogs

Abstract

To evaluate combined buccal mucosa and lingual mucosa grafts for urethroplasty in a dog model. Seven female mongrel dogs were randomly selected. After a segment of proximal urethra mucosa (4 cm × 1cm) was excised and onlayed urethroplasty was performed using the combined free buccal mucosa (2 cm × 1cm) graft harvested from the inferior cheek and free lingual mucosa graft (2 cm × 1cm) harvested from the inferior lateral surface of the tongue. A 12F urethral catheter was kept inside the urethra for a mean of 7 d. Retrograde urethrography was done and urethra diameter was calibrated with a 10Fr catheter before animals were sacrificed at wk 12. After sacrifice of all dogs, the grafted areas excised and evaluated by gross and histopathological examination. All dogs survived the procedure and there were no tongue and oral complications. One of the seven dogs developed a severe urethral stricture near the proximal anastomosis. The remaining six dogs voided spontaneously with no difficulty. Retrograde urethrography showed that no strictures or fistulas had formed. The combined buccal mucosa graft and lingual mucosa graft shortened by 10.2% after surgery, from a mean (SD) of 4 (0.15) to 3.59 (0.23) cm (statistical significance, P < 0.05). No stricture was found in the connection of the buccal mucosa and lingual mucosa grafts. Histologic examination showed that the combined buccal mucosa and lingual mucosa grafts were well-incorporated into the urethral walls and covered by a keratinized squamous epithelium. We successfully developed a dog model for combined buccal mucosa graft and lingual mucosa graft and showed the feasibility of this approach for urethral substitution.