Urethral substitution using autologous lingual mucosal grafts: an experimental study

Abstract

OBJECTIVE To investigate the feasibility of urethral substitution using free lingual mucosa grafts (LMGs) in a dog model. MATERIALS AND METHODS The study included 10 female mongrel dogs in which a 4 × 1 cm2 section of urethral mucosa was excised. The defect was immediately repaired with a size‐matched free LMG harvested from the inferior lateral surface of the tongue. A 12 F urethral catheter was kept inside the urethra for a mean of 7 days. At 3 months after the procedure, the patency of the urethra was assessed by both insertion of a 12 F catheter and by retrograde urethrography. Dogs were killed, the grafted areas excised, and evaluated by gross and histopathological examination. RESULTS All dogs survived the procedure and there were no tongue complications. One of the 10 dogs developed a slight urethral stricture near the proximal anastomosis. The remaining nine dogs voided spontaneously with no difficulty. Retrograde urethrography showed that no strictures or fistulas had formed. The LMGs shortened by 9.5% after surgery, from a mean (sd) of 4 (0.13) to 3.62 (0.11) cm (statistically significant, P < 0.05). Histological examination showed that the LMGs were well‐incorporated into the urethral walls and covered by a keratinized squamous epithelium. Neovascularization was evident beneath the grafts. CONCLUSION We successfully developed an dog model for free LMGs and showed the feasibility of this approach for urethral substitution.

Oral Mucosa Graft: An Ideal Substitute for Urethroplasty

“…The overall early stricture recurrence was 20.7%. (27) Since then a number of groups have investigated the feasibility of lingual mucosa graft urethroplasty (16, 17, 21-23, 25, 26, 29, 30, 36, 47) whether experimentally (17,21) or clinically, (16,22,23,25,26,29,30,36,47) alone or with buccal mucosa, (16,17) and with different urethroplasty techniques. (23,26,47) Barbagli et al (25) later described their early experience using LMG for urethral reconstruction in 10 patients with anterior urethral strictures.…”

“…(13) In February 2006, Simonato et al (20) described the results of the first pilot study on the use of the tongue as an alternative donor site for graft urethroplasty with good functional and aesthetic results. (20) One year later in a dog model, Song et al (21) investigated the feasibility of the LMG urethroplasty. Macroscopic examination of the graft showed no ulceration, calcification, strictures, diverticulae or fistula formation.…”

“…The junction between the graft and the normal urethra was discernible by its gross appearance, and the LMGs were tightly incorporated into the urethral walls. (21) Since then, numerous reports for the use of the lingual mucosa for urethroplasty were published in the last 5 years (16,(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)) emphasizing Simonato's conclusion that the mucosa of the tongue is a safe and effective graft material in the armamentarium for urethral reconstruction with potential minor risks of donor site complications. (27) …”

Preliminary experimental study of urethral reconstruction with tissue engineering and RNA interference techniques

“…Many tissues have been used for urethral reconstruction, including vascularized or free grafts of skin as well as buccal, lingual or colonic mucosa. 6,7 However, the limited amount of autologous donor tissue limited these types of reconstruction, especially for the patients with long segment of strictures. Moreover, complications, such as recurrence, pain, swelling and oral opening limitation, often occur during the long-term follow-up.…”

Oral Mucosa Graft

“…The mucosal covering the lateral and under surface of the tongue are the same in structure with that lining the rest of the oral cavity ( Song et al, 2007). The mucosa covering the tongue has no particular functional features, and like buccal mucosal, lingual mucosa has constant availability, is easy to harvest and has favorable immunological properties (resistance to infection) and tissue characteristics (a thick epithelium, high content of elastic fibers, thin lamina propria and rich vascularization) .…”