Italian surgeon G. Barbagli widely popularize oral mucosa grafting during augmentation urethroplasty (AU) in men with extended spongy urethral strictures from 1996 [1]. During the past decade, this type of AU proved its reliability and became the technique of choice in the treatment for this pathology [2][3][4]. Currently, surgeons use 5 main proposed types of graft fixation depending on the localization of the stricture, its extension, degree of narrowing, and personal preferences [5][6][7][8]. These types of AU include:

The application of the mentioned methods qualitatively improved the outcome of the surgical treatment for extended spongy urethral stricture in men. However, the accumulation of experience and evaluation of remote results revealed a significant level of complications. One of them was the formation of strictures in the distal (20 – 28%) and proximal (56 – 59%) graft anastomoses regardless of the applied AU technique [6][9][10][11][12].

Thus, the minimization of the risks of narrowing in the anastomotic zones between the buccal graft and the native urethra remains an acute surgical issue.

The study aimed to improve the outcome of augmentation urethroplasty, in particular, dorsal inlay (Asopa) technique, in patients with extended spongy urethral strictures by minimizing the risk of recurrent strictures.

The study is based on the results of surgical treatment in 90 patients aged 18 – 72 years old (median age 47 years old) with extended spongy urethral strictures. The diagnosis in patients was verified by ascending and micturition urethrocystography. In single cases, MRI and urethra endoscopy was performed.

The most common localization of strictures included bulbar and penile-bulbar urethra (47.8% and 31.1%, respectively) with variants of stricture extension from 4 cm to subtotal variant (median 6 cm).

Urethral obstruction was removed by a method of open surgery (buccal graft dorsal inlay augmentation urethroplasty). Seventy patients (group I) underwent dorsal inlay augmentation urethroplasty according to the Asopa technique, and 20 patients (group II) – according to the modified technique proposed by the authors.

The technique of modified augmentation urethroplasty [13]. After a standard dorsal inlay fixation of the graft proposed by Asopa along the dorsal semicircle. Besides, before suturing of the urethrotomy dissection along the ventral semicircle, surgeons elongated the urethrotomy dissection on both sides for 2 cm with further suturing of two diamond-shaped grafts over the distal and proximal areas of augmentation along the dorsal semicircle. After that, loop suturing of the remaining urethrotomy dissection was made along the ventral semicircle between the diamond-shaped grafts (Type 1).

In patients with additional proximal dissection of spongy urethra going to the bulbar urethra, two mattress sutures were placed on each edge of the urethrotomy dissection instead of a diamond-shaped graft. Suturing of the distal diamond-shaped graft was made as in the first case (Type 2). Both modifications of the techniques are presented in Fig. 1 and 2.

Postoperative follow-up. The postoperative period in the groups was evaluated by the healing of would in the perineum, scrotum, and ventral side of the penis, and lack of contrast agent congestion to the paraurethral space during control pericatheter urethrography on day 21 after urethroplasty. The lack of congestion provided grounds for the removal of the urethral catheter, restoration of non-assisted urination, and the patient’s discharge from the hospital. Such a course of the postoperative period was considered to be standard. Based on the principles of evidence-based medicine, the effectiveness of the surgical treatment for urethral stricture was evaluated six months after the surgery. The assessment of the surgery effectiveness included monitoring of the symptoms by IPSS scale, uroflowmetry, and retrograde urethrography and urethroscopy for the evaluation of the causes of obstructed micturition (in the case of favorable or unfavorable surgery outcome).

Statistical analysis. Statistical processing of the obtained data was performed using the specialized software SPSS 26 (SPSS Inc., Chicago, IL, USA). A comparative analysis of clinical parameters in both groups was performed considering the primary or repeated urethra surgery. The statistical analysis included several methods. Testing hypothesis on the equality of shares and mean values using Z-test was used to compare the groups. The non-parametric Mann-Whitney test was applied for the identification of differences in the parameters in groups with small samplings. The t-test for the equality of the mean values in two independent samplings was used for the evaluation of the significance of differences in the groups by the quantitative parameters. The differences were considered significant at 5% and 1% (p < 0.05 and p < 0.01, respectively).

The course of the early postoperative period in patients was characterized by a lower rate of complications in Group II in comparison with Group I and a higher rate of cases wherein they were not registered (80.0% vs 65.7%) (Table 1).

The spectrum of complications in the postoperative period is presented in Table 2. In 4 cases, patients developed urethral fistulas. More frequently (80.0% of cases), they developed in patients with recurrent urethral strictures, which required repeated surgery within 4-8 months.

The assessment of the treatment effectiveness six months after surgery was performed in 48 out of 70 patients (68.6%) in Group I and in 18 out of 20 patients (90.0%) in Group II. During the control examination, all patients had natural non-assisted micturition.

The evaluation of the lower urinary tract symptoms (LUTS) by the IPSS scale in Group I did not reveal any symptoms in 26 patients (54.2%) and revealed light symptoms in 13 patients (27.1%). Six patients (12.5%) had moderate LUTS and three patients (6.3%) had severe symptoms. Fourteen patients (77.8%) from Group II did not have any symptoms. Three patients (16.7%) had light symptoms, and one patient (5.6%) had moderate symptoms.

These data correlated with the parameters of the quality of life (QoL) in patients. The mean QoL score in Group I was 1.8 (± 1.8), and in Group II, the mean score was 1.6 (± 1.2) without any significant differences between them (p = 0.23).

The parameters of the maximal urination flow rate by the sixth month of the follow-up in Group I were 16.8 (±4.1) ml/s, and in Group II, 19.4 (± 2.7) ml/s (p = 0.004).

The evaluation of the remote results (six months after surgery) of AU is presented in Table 3. The main causes of ineffective results were strictures and deformations in the area of augmentation (Table 4).

Recurrent strictures in Group I were diagnosed in 9 patients (18.8%) with their localization in the areas of distal (5 cases) and proximal (2 cases) graft anastomoses with the spongy urethra. In 2 cases, the recurrence was associated with severe deformation of the graft in the area of augmentation.

In Group II, the disease recurrence was registered in one patient (5.6%) with the localization of the urethra stricture around distal graft anastomosis with the spongy urethra.

The authors considered short strictures in the distal and proximal anastomoses in patients from both groups as subcompensated urethral narrowing after urethroplasty provided they had moderate LUTS and preserved micturition. They were primarily resolved by the method of internal optical urethrotomy (IOUT).

IOUT was performed on eight patients out of ten in the general group. Two patients from Group I with severe graft deformation along the site of its fixation underwent open reconstructive urethral surgery.

One of a large-scale systemic reviews on the results of augmentation urethroplasty with buccal grafts was made by Chapple, Andrich, Atala et al. published in 2014 [14]. The main points of the review are presented in Table 5. It was noted that one of the main causes of urethral stricture recurrence after urethroplasty is an insufficient volume of urethrotomy performed along the site wherein the graft augmentation of the narrowed urethra is performed. This results in the formation of strictures in the area of graft anastomoses with the native urethra [9][15].

H. Asopa proposed a method of augmentation urethroplasty in 2001. It included consecutive dissection of the penile tissues to the ventral semicircle of the spongy urethra in the area of the stricture with further longitudinal dissection performed along with the stricture. After that, the second longitudinal dissection of the spongy urethra was made along the dorsal semicircle from the mucous part of the urethra. The augmentation of the urethra with a graft was made in the area of the dorsal dissection from the part of the urethral lumen. After the stage of augmentation, surgeons closed the urethra by suturing the urethrotomy dissection along the ventral semicircle spongy urethra with loop sutures [16].

The main “disadvantage” of the proposed method is the stage of longitudinal suture of the spongy urethra along the ventral semicircle of the urethra, especially over the edges of augmentation. It leads to the narrowing of the urethral lumen and increases the risk of stricture recurrence in the area of distal and proximal dissections.

In the present study, the authors showed the variants of new surgical techniques for dorsal inlay (Asopa) augmentation urethroplasty in patients with extended strictures of the spongy urethra that minimize the above-mentioned complications. The authors believe that due to an increase in the internal lumen of the urethra by suturing additional diamond-shaped grafts or placing mattress sutures in the area of the bulbar urethra.

The techniques proposed by the authors not only increase the internal urethral lumen after augmentation but also minimize ischemic manifestations in the area of spongy urethra urethrotomy that is sutured on a catheter. The catheter itself is located in the urethral lumen for not less than 21 days and creates at least minimal pressure on the urethral walls in the area of graft anastomoses and suturing along the ventral semicircle.

This is confirmed by the obtained results. The general rate of complications in the early and remote postoperative period was most frequently verified in patients that underwent conventional dorsal inlay (Asopa) surgery. They prevailed in cases of repeated surgery and wherein the tissues of the spongy urethra and paraurethral space already contained ischemic elements caused by fibrous changes.

The proposed and implemented modified technique of dorsal inlay augmentation urethroplasty increase the internal urethral lumen in the area of the proximal and distal anastomoses between the graft and the spongy body of the native urethra, which minimizes the risks of recurrent urethral strictures.