Introduction

The anterior urethra in men consists of three portions that are in continuity: bulbar urethra, penile urethra, and fossa navicularis—all are surrounded by the corpus spongiosal tissue. Anterior urethral strictures can be of traumatic, inflammatory, iatrogenic, or idiopathic origin and might involve the bulbar urethra, penile urethra, or both tracts. [1].

Many studies applied urethroplasty for the treatment of anterior urethral strictures. However, only few of these studies investigated the applicability and success of urethroplasty in patients with long-segment anterior urethral strictures [2–4]. A cut of 8–9 cm was used to define long-segment strictures in these studies. Dorsal–onlay graft urethroplasty (DOU) was first described by Barbagli et al. [5] in 1996. The technique is performed using either a penile skin graft (PSG) or buccal mucosa graft (BMG).

The primary outcome of the current study was to address the surgical outcomes of DOU—using BMG or PSG—in patients with long anterior urethral stricture. The secondary outcome was to determine the surgical outcomes of this technique in patients with strictures ≥8 cm long.

Patients and methods

From January 2008 to July 2015, male patients with anterior urethral strictures who were planned for urethroplasty at our department were included in this cohort prospective study. Inclusion criteria were men with bulbo-penile and penile urethral stricture. Exclusion criteria were: history of previous urethroplasty and lichen scleroses (LS). The institutional review board approved the study, and all patients signed an informed consent.

Surgical procedure

Surgeries were performed as described by Barbagli et al. [5] PSGs were obtained from the distal penile shaft by making a circular sub-coronal incision. It was not possible to use preputial skin in any of our patients as they were all circumcised. BMGs were obtained from the inner cheek. All procedures were done in one stage, in lithotomy or supine positions. Patients in the BMG group had general anesthesia and were nasally intubated. The urethra was dissected from the corpora cavernosa and rotated 180 degrees. The dorsal surface of the urethra was then opened to assess the length of the stricture, and the dissection was extended to include 1 more cm of healthy urethral tissue in both proximal and distal directions. The graft was defatted, fenestrated, and sutured over the corpora cavernosa using 6-0 vicryl stitches in interrupted manner (Fig. 1).

Fig. 1
figure 1

Penile skin graft was fixed dorsally against the corporal bodies

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The urethral margins were sutured onto the margins of the graft—in full thickness—using a single layer of interrupted vicryl sutures. Finally, a 16 F. silicone catheter was left in situ for 3 weeks. Patients with pre-operative suprapupic tube due to retention had the tube left in place for 4 weeks. Urethrography was done to excluded extravasation before the catheter was removed.

Follow-up

Urinalysis, urethrography, and uroflowmetry were performed preoperatively, then at 3, 6, 12 months, and then when needed, postoperatively. Urethroscopy was done on needed bases. Though we recognize the invasive nature of urethrography, we believe that it one of the most reliable methods to detect stricture recurrence.

Success was defined as patient urethra on postoperative urethrogram without narrowing. Any postoperative intervention including dilation was considered a failure in the study.

Statistical analysis

SPSS version 22 (SPSS, Armonk, NY, USA) was used for data analysis. Student’s t test and Mann–Whitney U tests were used to find differences between numerical variables with normal and abnormal distribution, respectively. Categorical variables were examined using Pearson’s Chi-square test. The level of significance was set to 0.05.

Results

Sixty-nine patients (43 ± 14 years old) were included in the study. Thirty-one patients received BMG, and 38 patients received PSG. Etiology of urethral stricture was: postinflammatory induced in 12 patients (17 %), endoscopy induced in 22 (32 %), unknown in 21 patients (30 %), and catheter induced in 14 (20 %). Thirty of the 69 patients (43.5 %) had the stricture at the penile urethra and 39 (56.5 %) at the bulbo-penile urethra.

The mean length of the stricture in the total group was 8 ± 3 cm (range 4–17). The mean operative time was 145 ± 31 min (range 90–246). The mean follow-up was 56 ± 10 months. Postoperative urethrograms showed patient urethral lumen in 60 of 69 (87 %). The mean maximum flow rate (Qmax), the mean postvoid residual urine (PVR), and the mean International Prostate Symptoms Score (IPSS) all significantly improved postoperatively (p < 0.0005).

Nine patients (13 %) developed recurrent urethral strictures: 3 in the BMG group and 6 patients in PSG group. The stricture recurred at the posterior anastomosis in 7 patients and at the mid-graft in 2 patients. All recurred strictures occurred between 1 and 2 years. Three patients received visual internal urethrotomy (stricture length <1 cm), 3 had anastomotic urethroplasty (stricture length 1–2 cm), and 3 had BMG urethroplasty (stricture length ≥3 cm). Patients who received redo BMG urethroplasty included 2 patients had primary PSG and one patient had primary BMG.

Complications occurred in 25 of 69 patients (36 %)—all were of grade I on Clavien–Dindo Classification Scale: Erectile dysfunction (ED) in 4 cases, urinary tract infection (UTI) in 5, wound infection in 7, and postvoid dribbling in 13 cases. Culture and sensitivity (C&S) test were done for patients with wound infection and/or UTI, and the proper antibiotics were given to them.

Table 1 shows a comparison of demographics and surgical outcomes between patients in the BMG group and patients in the PSG group. There was no statistically significant difference between the two groups regarding age, length of the stricture, preoperative Qmax, preoperative PVR, and preoperative IPSS. The operative time was significantly higher in the BMG group.

Table 1 Comparison of patients’ demographics and surgical outcomes between patients with PSG and patients with BMG
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Based on the type of graft, the success rate in the BMG group and PSG group was not statistically different (90 vs. 84 %, p = 0.4). Based on the site of stricture, the success rate was 86 % in patients with penile stricture, and 72 % in patients with bulbo-penile strictures. Based on the etiology of stricture, the overall success rate was 93 % for catheter-induced strictures, 90 % for strictures with unknown etiology, 83 % for inflammatory strictures, 82 % for endoscopy-induced strictures.

Thirty of the 69 patients (43 %) had a stricture length ≥8 cm. Table 2 shows a comparison of demographics and surgical outcomes between patients with stricture lengths <8 cm and those with strictures lengths ≥8 cm. Thirteen of 69 patients (19 %) received 2 grafts (all were one long structure), 12 of them (92 %) had stricture length ≥8 cm, and in 12 of them (92 %), the 2 grafts were harvested from the buccal mucosa.

Table 2 Comparison of demographics and surgical outcomes between patients with urethral strictures <8 cm (>3 cm) and patients with urethral strictures ≥8 cm
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Nineteen of the 39 patients with strictures <8 cm (49 %) received BMG and 20 (51 %) received PSG. Twelve of 30 patients with stricture ≥8 cm (40 %) received BMG and 18 (60 %) received PSG. The length of graft was significantly longer in strictures ≥8 cm than in stricture <8 cm. The success rate was equal for both subgroups (87 %). The mean blood loss, the mean operative time, and the number of patients who developed postvoid dribbling were significantly lower in strictures <8 cm. (Table 2).

Discussion

Our study shows that there is no significant difference using the penile skin or buccal mucosa as a dorsal onlay graft to repair a long anterior urethral stricture. Both grafts have comparable success rate with minor complications. Operative time is significantly shorter in the PSG urethroplasty patients than the BMG urethroplasty group. Furthermore, the stricture length has no influence on the success rate of repair of long anterior urethral stricture.

The overall success rate in our series was 87 % which is in accordance with many other studies—in a systematic review of studies applying free graft urethroplasty the overall success rate was 84.3 % [6]. Success rate in the PSG group of the current series was 85.7 %. This is in accordance with rates reported in previous studies (78.4–83.3 %) [7, 8]. The success rate in the BMG group of the current series was 90 % which is comparable to the success rate obtained from other studies—Warner et al. [4] reported 82.5 % success rate when applied BMG in a large series of 223 patients with a mean urethral strictures 12.7 cm (8–24) with a mean follow-up 20 (12–344) months. Kulkarni et al. [3] reported 83.7 % success rate when applied BMG in 117 patients with a mean urethral strictures 14 cm (10–18) with a mean follow-up 59 months (12.3–162.5). The relatively insignificant higher success in our study may be due to exclusion of previous failed urethroplasty cases.

In the current series, dorsal only approach was applied because it offers good support to the graft preventing its retraction, and therefore, increasing chances of graft survival [9]. However, it has to be mentioned that both dorsal and ventral onlay approaches have almost the same average success rate—88.8 vs. 88.4 %, respectively [10]. Complicated cases with failed previous urethroplasty and LS were excluded to determine the actual difference between BMG and PSG in absence of complex pathological and immunological disorders [11].

Penile skin has many advantages as a graft for urethroplasty including proximity to the operative field, easy harvest, and availability so, it has been popular and used for a long time [12]. On the other hand, buccal mucosa has thick epithelium, thin lamina propria, high content of elastic fibers and rich vascularization [13]. Buccal mucosa retains its histopathological characteristics after urethral engrafting [14].

In the current series, no statistically significant difference was found in the rate of success between the BMG and the PSG (90 vs. 84 %, p = 0.4). Almost the same observation has been reported by other groups—Barbagli et al. [11] reported a clinically insignificant difference in the success between BMG and PSG (82 vs. 78 %, respectively), and Soliman et al. [8] reported 84.6 vs. 81.8 % success for BMG and penile skin flap techniques, respectively. The operative time was significantly higher in the BMG group of our series; however, this could have been shortened if another surgical team had harvested the BMG at the beginning of surgery.

There is no worldwide standard definition of long-segment urethral stricture. However, some studies used a cutoff 8–9 cm to define a long urethral stricture [2, 4]. The mean length of urethral stricture in our series was 8 ± 3 cm. We intended to evaluate patients with relatively long stricture, and consequently patients with stricture length <4 cm (15 patients) were not included in the study. The success rates in patients with strictures ≥8 cm and those with strictures <8 cm were equal (87 %). The mean postoperative Qmax and PVR were slightly lower in patients with strictures ≥8 cm but without statistical or clinical significance. Four of the 9 failed cases in our series had preoperative stricture length ≥8 cm. However, the 60 successful surgeries included 26 (43 %) long strictures too—up to 17 cm. Barbagli et al. [11] reported that 11 of 13 cases with stricture length >6 cm were successful, while only 5 of 10 cases with stricture length 3–4 cm were successful in their series. Therefore, we think that the length of the stricture does not affect the rate of success or the functional outcome of the surgery. However, it is associated with longer operative time, more blood loss, and more occurrence of postvoid dribbling. About 60 % of patients with stricture lengths ≥8 cm received PSG in our series, while 40 % of them received BMG, which was obtained from both cheeks in 12 cases.

Nine of the 69 (13 %) patients in our series developed recurrent stricture, which is in accordance with recurrence rates reported in previous studies (10.5–17.5 %) [3, 4, 7, 8]. Our preference is to do direct vision internal urethrotomy for short stricture (<1 cm) and to do urethroplasty for longer stricture in failed cases.

A variety of complications of urethroplasty have been reported in the literature, such as postvoid dribbling, penile chordee, fistula, erectile dysfunction, and penile skin loss [4, 7, 8]. Complications occurred in 36 % of our patients—all were of grade I on Clavien–Dindo Classification Scale.

Our study has the advantage of being prospective. The shortcomings are the small sample size and lack of randomization. Longer follow-up is also needed.

Conclusion

Both BMG and PSG have a comparable success rate as a dorsal only for the treatment of long anterior urethral stricture. BMG has significantly longer operative time than PSG. Long-segment strictures are associated with longer operative time, more blood loss, and more occurrence of postvoid dribbling. However, the length of the stricture has no influence on the success rate and functional outcomes of dorsal onlay graft urethroplasty for long anterior urethral stricture.