UCF formation is a common and frequently discussed complication after surgical repair of hypospadias and other urethroplasties. Possible causes of UCF include a urethral stricture, suture line dehiscence, an inappropriate repair technique with inadequate inversion of the mucosa, the use of inadequate layers for closure, ischemic tissue, or overlapping of the suture lines leading to suture line leakage [3,4]. In the present study, UCFs developed after various urethral diseases and improperly performed urethral surgeries (urethral stricture, urethral stones, urethral diverticulum, circumcision, indwelling catheter, urethroscopy, and other conditions).
Direct closure of a UCF is a commonly performed and technically easy procedure; however, this treatment is associated with a higher recurrence rate . Possible reasons for repair failure are high tension of the direct suture line, leading to suture line dehiscence, and overlapping of the suture lines, leading to suture line leakage .
The frequency of UCF formation has decreased with increased surgeon experience, improvements in operative techniques, use of appropriate suture materials and instruments, and coverage of the urethra with well-vascularized tissue . Many studies have shown that placement of a covering layer between the urethra and the penile skin is advantageous for fistula repair. Many materials have been suggested as effective covering layer materials, such as a local scrotal dartos flap, external spermatic fascia, a tunica vaginalis flap, and others [ 7,8,9].
Although coverage techniques are now performed as a routine step by most surgeons, each attempted repair further depletes the local tissue and makes the treatment more difficult. The reported recurrence rate of coronal sulcus fistulas is substantially higher than that of fistulas in other locations. This is probably related to the lack of sufficient soft tissue adjacent to the fistula and the more pronounced traction effect of erection on the repaired fistula as it gets closer to the glans . To avoid this condition, we used a penile skin advancement flap to repair the coronary sulcus or distal UCFs. It is feasible and effective to treat the fistula with the penile skin advancement flap in the study. The advantages of this coverage technique are not only closure of the urethral fistula but also avoidance of direct communication between the fistula and the skin incision. The advancement flap we used can reduce the tissue deficiency and high tension of the incision; bring healthy, well-vascularized tissue over the urethral repair site; and avoid overlapping suture lines.
There is still a high recurrence rate of UCF after multiple operations of hypospadias, the lack of available surrounding materials and poor coverage are the main reasons. We designed the combined coverage technique. In this technique, the vascularity of the pedicled penile flap is maintained because it is harvested from the side opposite of where the skin advancement flap is raised. This procedure may avoid surgical failure caused by a poor blood supply to the skin. The combined coverage ensures stable adhesive formation between the UCF suture site and the penile skin tissue and promotes the healing of the UCF. When the penile skin advancement flap fully covers the skin wound, the principle of longitudinal, tension-free sutures should be followed. According to previous reports, pedicled tissue rotation may compromise the original shape of the penis , the advantages of the penile skin advancement flap are that it reduces the tension of the local penile skin and reduces the penile rotation and abnormal appearance.
The site and size of the fistula and the quality of surrounding tissues may affect the outcome of fistula repair [12,13]. In the present study, the overall success rate of UCF repair was 83.3%, and patients with larger or multiple fistulas were more likely to develop recurrence. Additionally, the success rate of perineal fistula repair was high in our study. We believe that tissues for a pedicled skin flap and perineal skin advancement flap are relatively abundant in that region, are easy to harvest, and have good blood supplies. Although the number of patients in our study was limited, these characteristics can effectively improve the success rate of UCF repair. No serious infection occurred in any patients after the operation in the study. We believe that tissue coverage with a good blood supply provides more resistance to infection than administration of antibiotics.
Several important principles of successful UCF repair should be kept in mind: tension-free closure, multilayer coverage with well-vascularized tissue, avoidance of overlapping suture lines, and correction of distal obstruction [14,15]. Our surgical experience and results have led to certain recommendations for UCF repair. Previous procedures can adversely influence the results of subsequent surgical attempts. Patients whose fistulas fail to heal must undergo urethral fistula repair 6 months after surgery to soften the tissue induration and decrease tissue fragility. The suture material is another important aspect of proper repair [16,17]. We used absorbable 6-0 polydioxanone sutures in our patients; nonabsorbable or thicker delayed absorbable sutures should be avoided because the suture itself can cause fistula tract formation when it remains in place for a prolonged period of time.