Tunica Vaginalis Pedicle Flap for Reconstruction of Anterior Urethral Stricture

Authors


Abstract

Objective

To evaluate the intermediate-term clinical efficacy and success rate of tunica vaginalis (TV) pedicle flap for reconstruction of bulbo-penile urethral stricture.

Methods

We assessed the medical records of 15 male patients who had undergone TV pedicle flap urethroplasty for reconstruction of anterior urethral stricture between January 2006 and December 2011. The surgical outcome was assessed by comparison of four parameters including the maximum flow rate (Qmax), international prostate symptom score (IPSS), residual urine (RU) and quality of life (QOL) in all patients pre- and postoperatively. Moreover, pre- and postoperative retrograde urethrography films were compared in all patients. t-test was used for data analysis.

Results

The mean patient age was 38.1 ± 9.3 years (range: 25–55), mean stricture length was 4.2 ± 1.1 cm (range: 3–6.1 cm), and the mean follow up time was 14.6 ± 1.9 months (range: 12–18) months. There was a statistically significant difference between Q(max), IPSS, RU and QOL pre- and postoperatively (P < 0.01). The clinical success rate in this study was 86.6% (13/15). The early complication was one case of wound infection and subsequent wound dehiscence, one case of hematoma formation in another patient, which did not have any influence in the long-term clinical outcome.

Conclusion

At intermediate-term follow up, TV pedicle flap urethroplasty has a high clinical success rate with low complication. However, a large clinical trial with long-term follow up is needed to confirm the result.

1. INTRODUCTION

The acquired urethral stricture is a fibrotic narrowing, composed of dense collagen and fibroblast. Fibrosis usually extends into the surrounding corpus spogiosum and causes spongiofibrosis, narrowing the urethra, restricting urine and causing subsequent back pressure phenomena.[1] The incidence rate of acquired urethral stricture was roughly estimated to be 0.6%, which is more common in elderly patients beyond 55 years of age.[2] Despite relatively low incidence of stricture, the treatment is quite difficult and obtaining a satisfactory long-term outcome is a formidable challenge.

A great variety of tissues has been tried as flaps or grafts to substitute the urothelium both experimentally and clinically. These include a mucosal graft,[3] skin graft,[4] intestinal sub mucosa graft,[4] bladder mucosa[4] and peritoneal graft.[4] Also various surgical techniques have been used, but no ideal graft or flap has been identified yet. Tunica vaginalis testis (pars parietal) is another tissue donor site that has the capability of being used both as flap and free graft. In clinical practice, it has usually been used as a second layer for augmentation in a tabularized incision plate (TIP) in order to prevent subsequent urethrocutaneous fistula formation.[5] Also it has been used for correction of penile cuvature (chordee)[6] and surgical treatment of Peyronie's disease.[7] Many experimental studies[8-12] and a few clinical studies[13, 14] have reported the feasibility and usefulness of using tunica vaginalis for definitive urethroplasty in anterior urethral strictures. The majority of those experimental studies have revealed that tunica vaginalis mesothelium was gradually replaced by a more stratified epithelial lining similar to the urethral lining of the native urethra.

In the current study, we retrospectively evaluated the clinical efficacy and feasibility of tunica vaginalis (TV) pedicle flap for reconstruction of anterior urethral stricture by comparing some clinical parameters including the urinary flow rate (Qmax), international prostate symptom score (IPSS), patients quality of life (QoL) and residual urine (RU). The pre-operative result was compared 3 and 12 months postoperatively.

2. METHODS

After obtaining institutional ethical review board approval, 15 male patients who had undergone Tunica vaginalis pedicle flap urethroplasty between January 2006 and January 2011, were retrospectively assessed. The procedure was allocated for patients who had not enough penile skin, including those who had previous failed attempts of urethroplasty and those who had already underwent circumcision. Before surgery, the length of stricture was determined according to radiology reports and conventional retrograde urethrography plus voiding cystourethrography. During surgery, it was measured, using centimeter ruler. The urethroplasty had been done with two different techniques: TV pedicle flap ventral on lay urethroplasty (nine patients), and TV pedicle flap tubularized substitution urethroplasty (six patients). In order to assess the clinical efficacy and success rate of the surgical technique, the pre-operative Q(max), IPSS, QoL, RU were compared with them 3 and 12 months postoperatively. In order to know if there was change in caliber of urethra over time, the comparison was done between them at 3 and 12 months postoperatively. The t-test was used for statistical analysis. Moreover, pre-operative and postoperative retrograde urethrography was compared (Figs 1, 2). Van Buren urethral sounds (16–18 Fr) were used for checking and dilating the reconstructed part at 3 month intervals after surgery. Finally, Fisher's exact test was used to find any difference between success rates of two aforementioned surgical techniques.

Figure 1.

Pre-operative retrograde urethrography in a patient with long stricture, which extended form the bulb to most of the penile urethra.

Figure 2.

One year postoperative urethrography of the same patient. In this patient the combination of tunica vaginalis pedicle flap and penile skin were used.

2.1 Surgical technique

Under epidural anesthesia the patient was placed in the lithotomy position. After the conventional prep and drape, location of the stricture was determined by direct palpation on urethra then skin incision was done along the urethra. After dissection of the subcutaneous tissue, corpus spongiosum and visualization of urethra, it was opened longitudinally over the structured segment and continued up to the normal urethra. Then a 2–3 cm vertical incision was done on the anterior wall of the hemiscrotum (Fig. 3), the attachment of the Tunica vaginalis with the scrotal wall was dissected and the testis was removed from the scrotal incision. According to the length and stricture status, the parietal tunica vaginalis testis was harvested in form of vascularized pedicle, then the harvested flap was transferred to the stricture site and according to the status of stricture, one of the following surgical techniques was preferred: ventral on lay TV pedicle flap urethroplasty or tubularized TV pedicle flap urethroplasty. In cases with acceptable dorsal urethral wall (roof of urethra), the ventral onlay technique was done while others were treated with the tubularized technique.

Figure 3.

Showing tunica vaginalis dissected form left testis.

In the ventral onlay method, the TV flap was tunneled over 16–18 Fr Foley catheter then sutured to urethral plate by 6-0 polyglactin (Fig. 4) whereas in the tabularized technique the TV flap was tubed around a Foley catheter, then sutured and anastomosed with proximal and distal urethra. The suture line was placed dorsally, in the hope of preventing fistula formation (Fig. 5). The surgical wound was dressed under pressure to prevent hematoma formation around neourethra. Finally the testis was replaced in the scrotal pouch. After putting a Penrose drain in the scrotum, the scrotal incision was closed.

Figure 4.

Showing ventral onlay tunica vaginalis pedicle graft after suturing to urethral plate.

Figure 5.

Showing tunica vaginalis pedicle graft after making new urethra in form of tabularized around the Foley catheter.

At the end of the operation in both techniques a tube catheter was put in the urethra beside the Foley catheter up to level of neourethra in order to instill antibiotics. Cephalosporin parenteral antibiotic was used prophylactically for 3 days, then an oral antibiotic was used until catheter removal. The Foley catheter was removed after 2-weeks, and then a voiding cystourethrogram was done in all cases.

3. RESULTS

Of 15 patients who underwent TV pedicle flap urethroplasty, ventral onlay was done in nine patients and tabularized technique was done in six patients. The mean age of the patients was 38.1 ± 9.3 year (range: 25–55) year. The mean stricture length was 4.26 ± 1.1 cm (range: 3–6.1 cm) and mean follow up time was 14.6 ± 1.9 months (range: 12–18 months).

The mean pre-operative Q(max) was 7.5 ± 1.9 mL/s whereas it was 18.3 ± 2.9 and 17.8 ± 2.8 mL/s at 3 and 12 months postoperatively, respectively, which was a statistically significant difference between pre- and postoperative at both 3 months (P < 0.01) and 12 months (P < 0.01) (Table 1).

Table 1. Showing great changes (mean ± SD) in Qmax, IPSS, QOL and RU on 3 and 12 months after operation
GroupQmaxIPSSQOLRU
 (mean ± SD)(mean ± SD)(mean ± SD)(mean ± SD)
  1. * and ** compared in pre-operative data. * and ** compared between them (P > 0.05). IPSS, International prostate symptom score; Qmax, maximum flow rate; QoL, quality of life; RU, residual urine; SD, standard deviation.
Pre-operative7.5 ± 1.928.0 ± 2.94.3 ± 0.785.6 ± 6.0
3 months postoperative18.3 ± 2.9* (P < 0.01)6.1 ± 4.1* (P < 0.01)1.1 ± 0.8* (P < 0.01)25.6 ± 8.5* (P < 0.01)
12 months postoperative17.8 ± 2.8** (P < 0.01)6.8 ± 4.1** (P < 0.01)1.3 ± 0.6** (P < 0.01)27.1 ± 8.5** (P < 0.01)

The mean pre-operative IPSS was 28.0 ± 2.9 while it was 6.1 ± 4.1 and 6.8 ± 4.1 at 3 and 12 months postoperatively, respectively, which was a statistically significant difference between pre- and postoperatively at both 3 months (P < 0.01) and 12 months (P < 0.01), but there was no statistically significant difference between 3 and 12 months postoperatively (P > 0.05) (Table 1).

The mean pre-operative QOL was 4.3 ± 0.7, while it was 1.15 ± 0.8 at 3 months and 1.3 ± 0.6 at 12 months postoperatively, which was a statistically significant difference between pre- and postoperatively at both 3 months (P < 0.01) and 12 months (P < 0.01), but the difference between 3 and 12 months postoperatively was not statistically significant (P < 0.05) (Table 1).

The mean pre-operative RU was 85.6 ± 6.0 mL while it was 25.6 ± 8.5 mL at 3 months and 27.1 ± 8.5 mL at 12 months postoperatively. The difference between pre-operative RU and postoperative both at 3 months (P < 0.01) and 12 months (P < 0.01), but the difference between 3 and 12 months postoperatively was not statistically significant (P < 0.05) (Table 1).

According to the result of statistical analysis, which was summarized in Table 1, the patients become asymptomatic. Maximum urinary flow rate rose up to its normal range, good quality of life ensued, and no significant post-voiding residual urine appeared. This result indicates that TV pedicle flap urethroplasty is a safe and successful procedure for patients with anterior urethral stricture. There were few changes in clinical parameters between 3 and 12 months postoperatively, but the differences were not statistically significant.

An early postoperative complication was one case of wound infection and subsequent wound dehiscence in tabularized technique and also one case of hematoma formation in ventral onlay technique. Wound infection was resolved by 2-weeks of antibiotic therapy and the hematoma was drained. In one patient on the tabularized technique, re-stricture developed, while in the onlay technique, one case of urethro-cutaneous occurred. Both of them were considered failed cases. There was no other complication like penile curvature (chordee) in our series. The total success rate in our study was 86.6% (13/15). There was no statistically significant difference between success rate of tabularized and ventral onlay technique.

4. DISCUSSION

A great variety of tissues from the genital and extra genital area have been tried both experimentally and clinically for a flap or free graft. These include the fasciocutaneous component of the penis, bucal mucosa graft, vesicle mucosa, small intestinal sub-mucosa and peritoneum.[4] Besides that, several surgical techniques have been launched to find an ideal substitute for the urethra, but it seems that the ideal graft or flap has not been identified yet.

Based upon many previous experimental studies, we clinically evaluated the feasibility and usefulness of tunica vaginalis pedicle flap for reconstruction of anterior urethral stricture in the form of ventral onlay and tabularized techniques. Our sample comprised 15 adult men with bulbo-penile acquired urethral stricture, of which nine underwent TV-ventral onlay and six underwent TV-tubularized urethroplasty. An early postoperative complication was one of wound infection and subsequent wound dehiscence in the tubularized technique and one case of hematoma formation in the ventral onlay technique. In addition we had one case of re-stricture later in the tubularized technique and one urethracutaneous fistula in the onlay technique. We did not have any case of penile curvature (chordee) on the base of surgery in our series. Compared with other studies, this is an acceptable complication. All parameters – including maximum urinary flow rate (Qmax), IPSS, QoL and residual urine were much improved after the operation, which indicates the usefulness of TV pedicle flap for urethroplasty. Moreover, there was no significant difference in the abovementioned parameters between 3 and 12 months after surgery. It means that significant changes have not occurred on the caliber of the urethra during the interval of 9 months. This result leads us to extrapolate a positive long-term outcome of our study.

Tunica vaginalis has several favorable characteristics for use as pedicle flap in urethroplasty including close proximity to the surgical field, easy availability, high vascularity, and good resistance for handling during surgery[4, 11] Also another important characteristic is that the tunica vaginalis form of the pedicle flap does not need a serum imbibitions phase early after surgery. The ultimate outcome of any grafting including urethroplasty depends on revascularization of the donor graft by abundant vascularity of the recipient site. But initial viability of the graft, especially during first 24–48 h after grafting when revascularization is not established is clearly dependent on the serum imbibitions phase. In this phase 02 and other important nutrients are transported to the basal cell of epithelium via lamina propria by diffusion, which is called the serum imbibitions phase.[15] The vascularity of the tunica vaginalis as a pedicle flap will be intact. Thus there is no need for a serum imbibitions phase for initial viability.

Before our study, tunica vaginalis had been used for four main purposes: correction of penile chordee, as a second layer for augmentation of neo-urethra during tubularized incised plate (TIP), substitution of urethra for anterior urethroplasty, and surgical treatment of Peyronie's disease. Regarding its use in urethroplasty, several experimental and a few clinical studies have been carried out. Historically, in 1967 Ariyoshi[9] reported the first use of tunica vaginalis for urethroplasty in an experimental study. After that, in 1987 Talja et al.[10] used it as a ventral onlay graft. In 1988 Khoury et al.[11] used tunica vaginalis as a tubularized flap. In 1998 Theodorescu et al.[12] compared tunica vaginalis ventral onlay with tubularized and found that ventral onlay is better than tubularized for tunica vaginalis urethroplasty. Two studies in 2005 by Calado et al.[16] and also another in 2009 by Leslie et al.[17] reported the use of tunica vaginalis as a dorsal graft. Finally in 2010 Rosito et al.[8] reported its use as a dorsal graft in the first stage of Braka's urethroplasty. Interestingly, all of the above experimental studies (regardless of surgical technique used) reported the same histological result, which was “gradual replacement of tunica vaginalis mesothelium by a more stratified epithelial lining, similar to the urothelial lining of the native urethra.” Hutschenreiter et al.[18] in an experimental study reported quite different results to others. According to their study, tunica vaginalis has the ability of conversion to urothelium like lining when it is placed in the urinary tract. Before our study, the usage of tunica vaginalis for urethroplasty was clinically evaluated by three studies with different results. In 1999 Joseph and Perez[13] reported the use of tunica vaginalis as a patch on urethra in 10 boys and one man. The result was three meatal stenosis and three narrowing. It led the authors to believe there was no advantage of using tunica vaginalis. In 1992 Snow and Cartwright[19] reported the use of tunica vaginalis in three difficult cases. The result was meatal stenos in all three cases but the authors believe that the cause of meatal stenos was inflammation. Finally in 2007, Foinquino et al.[14] reported the usage of tunica vaginalis as a dorsal graft in 11 patients with 100% success rate and postoperative urine flow rate >14 mL/s in all patients. In our study, we had an 86.6% success rate and two cases failed. The mean urine flow rate at 3 and 12 months after surgery was 18.3 and 17.8 mL/s, respectively, which is quite similar to Foinquino's study – but the success rate in our study was lower than that done by Foinquino.

According to the previous study, the most well established clinical use of tunica vaginalis is as a second layer in hypospadiasis surgery (TIP) for the prevention of urethrocutaneous fistula. Snow[20] in 1986, Routh et al.[5] in 2006, Xue et al.[21] in 2007 and Kamyar Tavakkoli Tabassi and Mohammadi[22] in 2010, reported a significant reduction in urethrocutaneous fistula after using tunica vaginalis for augmentation of neourethra during hypospadiasis surgery (TIP). Another previous study[23] compared tunica dartos and tunica vaginalis as pedicle wrap for TIP in primary hypospadiasis and concluded that the tunica vaginalis pedicle wrap may be a good alternative to others. Regarding its use for correction of penile curvature, several clinical and experimental studies reported good results. Das and Maggio[7] used it for treatment of Peyronie's disease, Purlmutter et al.[6] for correction of chordee, Ritchey and Ribbeck[24] for treatment of chordee and Amin et al.[25] for correction of chordee in dogs, reported successful results using tunica vaginalis. The feasibility and usefulness of tunica vaginalis for augmentation of TIP has been established by several previous studies as mentioned before and also, regarding its use in urethroplasty, several animal experimental studies revealed its feasibility for urethral reconstruction. However, there are a few clinical studies with small sample and poor results. In this study, our result showed that the tunica vaginalis is a good tissue flap to be used clinically for reconstruction of bulbo-penile stricture with good clinical outcome and acceptable complications.

5. CONCLUSION

In conclusion, our clinical result with tunica vaginalis showed that the tunica vaginalis pedicle flap for reconstruction of anterior urethral stricture had a high success rate with acceptable complications. Also it has good tissue characteristics, like close proximity to the surgical field, easy availability and good resistance for handling. However, further studies and long-term follow up are needed to confirm the result.

Disclosure

The authors declared no conflict of interest.

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