Substitution urethroplasty for anterior urethral strictures: a critical appraisal of various techniques

Authors


A. Kumar, Department of Urology, SGPGIMS, Raebareli Road, Lucknow-226014, India.
e-mail: anant@sgpgi.ac.in

Abstract

OBJECTIVE

To retrospectively compare the outcome of various techniques of substitution urethroplasty.

PATIENTS AND METHODS

Between 1989 and 2000, 109 patients (mean age 39.5 years) underwent substitution urethroplasty for recurrent anterior urethral strictures. Between 1989 and 1995 the procedure was by ventral placement of free grafts (bladder mucosa, buccal mucosa, penile skin) or penile skin flaps. From 1995 onwards the flaps and grafts (buccal mucosa) were applied either ventrally or dorsally. Stricture recurrence and the complications associated with each technique were compared.

RESULTS

Ventral onlay repairs were associated with a higher incidence of complications than dorsal repairs, e.g. postvoid dribbling (39% vs 23%, P = 0.01), ejaculatory dysfunction (20% vs 5%, P = 0.03) and flap/graft pseudo-diverticulum or out-pouching (26% vs 2.6%, P = 0.01). Superficial penile skin necrosis was significantly more common with the use of penile skin flaps than with free grafts. There was no significant difference in stricture recurrence, erectile dysfunction and residual penile deformity among the various techniques.

CONCLUSIONS

Dorsal free graft/flap onlay urethroplasty gives better results than ventrally placed free grafts/flaps. Dorsal onlay buccal mucosal urethroplasty is a versatile procedure and associated with fewer complications than other substitution methods.

INTRODUCTION

Anterior urethral strictures that are too long to be excised and re-anastomosed are best treated with substitution urethroplasty using free grafts or pedicled skin flaps [1]. Both penile skin flaps and buccal mucosal grafts have emerged as reliable urethral substitutes with comparable long-term results [2,3]. Some have recommended buccal mucosal grafts over flaps for patch urethroplasty [4], whereas others find flaps more reliable [5]. In recent years dorsal placement of flaps (Bhandari et al., unpublished) and grafts [6] has been shown to be more advantageous than the traditional ventral onlay (VO). With the availability of numerous tissues and approaches for reconstruction, the challenge lies in choosing the appropriate technique for a particular stricture. We reviewed our experience with dorsal and VO substitution urethroplasty using free grafts and skin flaps, to determine the outcome and particular problems associated with each technique.

PATIENTS AND METHODS

Between 1989 and 2000, 109 patients (with an adequate follow-up) and with recurrent urethral strictures underwent substitution urethroplasty with either pedicled skin flaps or free grafts. The mean (range) age of the patients was 39.5 (11–62) years and the stricture length 6.2 (3–16) cm. The cause was inflammatory in 44, ischaemic (after catheterization) in 11, traumatic in 21, and unknown in 33. The stricture was in the pendulous urethra in 14, pendulobulbar in 39 and bulbar in 56. All patients had had previous urethral instrumentation in the form of several dilatations or internal urethrotomy. In addition, 22 patients had undergone a failed anastomotic urethroplasty elsewhere. Fifty-three patients had a suprapubic cystostomy for urinary retention and in 56 the mean (range) preoperative flow rate was 6.3 (3–9.4) mL/s. Between 1989 and 1995 patients were treated with a ventral onlay graft/flap urethroplasty, and from 1995 onwards the urethral substitutes were placed either ventrally or dorsally on the corporeal bodies. This led to the formation of four study groups, ventral flaps (VF), dorsal flaps (DF), ventral grafts (VG) and dorsal grafts (DG). The four groups were comparable in terms of proportion of pendulous/bulbar and pendulobulbar strictures, and mean stricture length (Table 1). For further comparison, patients with dorsal (flap and graft) onlays (DO) were compared with those having undergone VO. Penile skin flaps were developed using the techniques described previously [7–9]. Free grafts were harvested using previously described techniques of buccal mucosa [10], bladder mucosa [11] and penile skin [12]. Dorsal onlay skin flap urethroplasty was conducted using the technique described by Bhandari et al. (unpublished) and DO urethroplasty through a single perineal incision, as described by Kulkarni et al.[13].

Table 1.  The stricture characteristics and results of various techniques
CharacteristicVFDFVGDGP
  • chi-square;

  • *

    t -test, for < 0.05 VF vs VG and DG, DF vs VG and DG;

  • < 0.05 VG vs DF, DG and VF;

  • < 0.05 VF vs DF and DG.

No. of patients52231816 
Mean (sd) stricture length, cm  6.0 (2.6)  6.56 (2.3)  4.22 (1.6)  6.9 (2.9)< 0.05*
Pendulous/bulbar/pendulobulbar, n  8/24/20  6/8/9  0/14/4  0/10/6NS
Penile skin necrosis, n (%)12 (21)  4 (17)  1  0< 0.05
Penile angulation/torsion, n (%)  6 (12)  3 (13)  0  1 (6)NS
Diminished penile sensation, n (%)  5 (10)  2 (9)  0  1 (6)NS
Recurrence, n (%)12 (23)  4 (17)  4 (22)  2 (13)NS
Mean (sd) follow-up, months37.8 (19)22.4 (11)45.7 (13)22 (10.3)< 0.05*

After urethroplasty all patients were maintained on urethral and suprapubic catheter drainage for 2–3 weeks, after which VCUG was undertaken. Any extravasation (fistula) was treated by extending the period of catheterization (maximum 4 weeks). The subsequent follow-up included uroflowmetry and urethral calibration at 6-monthly intervals. Contrast medium studies were conducted at 6, 12 and 18 months, and subsequently when required. The incidence of fistula, penile skin complications, ejaculatory/erectile dysfunction, postvoid dribble and recurrence were recorded. Failure was defined as the need to use dilatation or internal urethrotomy. Differences between the groups were assessed using chi-square and t-tests where appropriate.

RESULTS

The proportion of pendulous/pendulo-bulbar and bulbar strictures was similar in all groups (Table 1). The mean stricture length in the VG group was significantly less than that in the other groups (Table 1). Seventy-five patients underwent substitution urethroplasty using pedicled penile skin flaps, whereas 35 had their urethra replaced with free grafts. Of the 75 patients, 23 had a DF urethroplasty (10 circumpenile, seven preputial and six longitudinal penile) and 52 a traditional VF (26, 18 and eight, respectively). In patients with graft replacement, 16 had DG (all buccal mucosal) whereas 19 had VG (seven buccal mucosal, and six each of penile skin and bladder mucosa). In six of 16 patients with DG, several buccal mucosal grafts were used. Of patients undergoing penile skin flap urethroplasty more had significant penile skin necrosis than those with free grafts (Table 1). Penile angulation/torsion deformity and diminution in penile sensation were higher in patients with DF and VF than with VG and DG, although this was not significant (Table 1). Fistulae were more common in VO than DO, although this difference was not significant (Table 2). Ejaculatory dysfunction (decrease in quantity of ejaculation) was more common in VO (Table 2). Patients had postvoid dribble with all types of urethroplasty (Table 2), but significantly more patients with ventral repairs reported this problem than with dorsal repairs. Also, the degree of postvoid dribbling was more severe in VO patients, as many of them had to resort to manual compression of the perineum to evacuate the pooled urine. Flap pseudo-diverticulum (Fig. 1) and sacculation (Fig. 2), as seen on urethrograms, were also more common with ventral repairs (Table 2). The mean follow-up was longer for patients undergoing VG and VF (Table 1). Stricture recurrence was not significantly different among the four groups (Table 2), and the incidence of erectile dysfunction was similar between DO and VO (Table 2).

Table 2.  Comparison of complications after DO and VO
ComplicationDOVOP
Number of patients3970 
N (%):
Fistula  5 (13)15 (21)0.1
Ejaculatory dysfunction  2 (5)14 (20)0.03
Erectile dysfunction  3 (8)  7 (10)0.88
Post-void dribble  9 (23)27 (39)0.01
Urethral pseudo-diverticulum/ outpouching  1 (3)18 (26)0.01
Figure 1.

A urethral pseudo-diverticulum after a VO graft urethroplasty for a bulbar urethral stricture; the patient subsequently had incontinence and ejaculatory dysfunction.

Figure 2.

Sacculation of a ventrally applied skin flap for a pendulous urethral stricture; the patient subsequently had significant postvoid dribbling.

DISCUSSION

The development of substitution urethroplasty techniques highlights the efforts to restore urethral anatomy and function to as near normal as possible. Over the years the preference has changed between flaps and grafts as a urethral substitute. Penile skin flaps and buccal mucosal free grafts have emerged as reliable urethral substitutes with comparable long-term results [5]. In the 1990s there was a radical change in the anatomical positioning of the flap/graft. Previously flaps and grafts were applied ventrally on the urethra, which resulted in complications like pseudo-diverticulum, postvoid dribbling and ejaculatory dysfunction [14]. Barbagli et al.[15], and subsequently others [16], reported that placing the free graft dorsally on the corpora resulted in better support and neovascularization. Bhandari et al. (unpublished) showed that dorsally placed pedicled flaps are anatomically and functionally better than the traditional VO.

Our practice of anterior urethroplasty reflects the emerging trends; in the early part of this series, flaps and grafts were applied ventrally, whereas from 1995 both grafts and flaps have mostly been applied dorsally. Consequently patients with ventral repairs have had a longer follow-up.

Stricture recurrence was not significantly different amongst the four groups. We concede that this factor cannot be compared in the true sense, as the follow-up for ventral repairs is longer. However, recurrence rates at comparable lengths of follow-up were no different. The focus of this study was to determine the peculiar complications associated with each procedure.

Patients with ventral flap/graft onlays had a higher incidence of fistula, troublesome postvoid dribbling, flap out-pouching/diverticulum formation and ejaculatory disturbance in the form of scanty ejaculation. Fistula was more common in VO than DO, although most healed spontaneously. The low incidence in DO was possibly because the suture line is well supported and protected between the corporeal bodies and the urethra. Postvoid dribbling occurred after both dorsal and ventral repairs but was more common and bothersome in patients who underwent VO urethroplasty. In the VO group most patients with postvoid dribble required manual perineal compression to evacuate the pooled urine. This corroborated with the presence of flap out-pouching and pseudo-diverticulum formation on follow-up urethrography. Coursey et al.[17] suggested that careful tailoring of the flap to 1.5–2.0 cm wide could avoid this complication. In their series of 66 patients, flap pseudo-diverticulum occurred in only 2%. However, Rogers et al.[18] reported bagginess and pouch formation of ventrally applied flaps in 17 of 114 (15%) patients. In the present series patients with dorsally placed skin flaps/grafts had a significantly better outcome, as shown by a lower incidence of these complications. Barbagli et al.[15] reported a negligible incidence of urethrocele formation and ejaculatory dysfunction in their patients treated with dorsal skin graft urethroplasty. Mundy [6] reported a higher recurrence and complication rate with ventral patch repairs than with dorsal patch grafts. Bhandari et al. (unpublished data) showed that dorsal placement of the flaps is particularly advantageous over ventral flaps in reconstructing meatal strictures, placing the flap more proximally on the bulbar urethra, and when used in combination with a free graft.

When comparing free graft with pedicled flap repairs, the latter had a higher incidence of penile skin necrosis. Although minor in most cases, it resulted in delayed healing and prolonged hospitalization. This is an inherent disadvantage of any pedicled penile skin flap, although in experienced hands it may not be as common [2]. Of 74 patients with flaps 11 also noticed numbness and diminished sensation over an area of penile skin and nine felt that penile angulation/torsion was significant after urethroplasty. Although not reported by others [2], Greenwell et al.[4] noted similar complications of skin flap urethroplasty. While comparing flaps with grafts, Rogers et al.[17] found a slightly higher incidence of sexual dysfunction with the former. Significant erectile dysfunction was uncommon in both groups. Although our experience with dorsally placed grafts is limited, the early results have been gratifying. In six of the DG patients the stricture extended into a significant portion of the pendulous urethra, including three with associated meatal strictures (balanitis xerotica obliterans). None of these patients have yet had any erectile dysfunction. Some have expressed concern that placing buccal mucosa on the pendulous urethra may result in chordee because the graft is inelastic [16] and others [19] reported a high failure rate with grafts applied to the pendulous urethra. However, in our experience and that of others [13] dorsal onlay of buccal mucosal grafts has resulted in none of these complications. Perhaps spread fixation of the graft on the corporeal bodies diminishes the chance of graft contraction. The length of the stricture has not been a problem, as several strips of buccal mucosa can provide up to 15 cm of graft (Fig. 3a,b). Moreover, the principal advantage of the technique used for dorsal buccal mucosal free graft urethroplasty is that the procedure does not involve violating the penile skin (as do penile skin flaps). Moreover, it is particularly useful for the simultaneous correction of meatal strictures associated with balanitis xerotica obliterans, where use of penile skin is contraindicated [19–21]. Although the present follow-up of dorsal buccal mucosal grafts is limited, others [3] have reported excellent long-term results, comparable to those with flaps.

Figure 3.

a, A contrast study before surgery in a patient with an inflammatory pan-urethral stricture; b, VCUG at 6 months after management with several dorsal onlay buccal mucosal grafts.

In view of the complexity of penile skin flaps with their inherent problems, as experienced by us and others [4], we advocate the following protocol. For an isolated pendulous urethral stricture, a longitudinal penile skin flap dorsal onlay; for balanitis xerotica obliterans with an anterior urethral stricture, a buccal mucosal dorsal onlay urethroplasty; for a pendulobulbar stricture, a buccal mucosal dorsal onlay or circumpenile flap dorsal onlay or a combination of these, depending on stricture length; for a bulbar urethral stricture, a buccal mucosal dorsal onlay or transverse preputial/circumpenile flap dorsal onlay; for a panurethral stricture combination of dorsal skin flap (pendulous) and dorsal buccal mucosal graft (bulbar).

ABBREVIATIONS
VF

ventral flaps

DF

dorsal flaps

VG

ventral grafts

DG

dorsal grafts

DO

dorsal onlay

VO

ventral onlay.

Ancillary