Early experience with the use of buccal mucosa for substitution urethroplasty

Authors


Mrs Venn Institute of Urology, 48 Riding House Street, London W1P 7PN, UK.

Abstract

Objective

 To evaluate the early results of anterior urethroplasty using a one-stage free graft with buccal mucosa.

Patients and method

 Thirty-nine patients (aged 23–59 years) underwent a one-stage urethroplasty using buccal mucosa, 28 as a patch and 11 as tube grafts. All patients were evaluated by post-operative urethrography at 6 months and were followed using urinary flow rates and symptoms for 2–5 years.

Result

 There was one recurrent stricture (3%) in the group with a patch urethroplasty but five of the 11 patients with tube grafts had a recurrent stricture.

Conclusion

 The early results using buccal mucosa for patch urethroplasty are encouraging. Although the results from tube grafts are poor, they are similar to those from other methods of single-stage urethroplasty.

Introduction

There are several techniques for substitution urethroplasty when excision of the stricture and end-to-end anastomosis is not possible and some form of extraneous tissue is needed as a patch or a tube. Various tissues have been used as the material for these procedures, either as free grafts [ 1], or flaps [ 2, 3], mainly using local skin. In recent years alternative tissues have been suggested, including bladder [ 4] and buccal mucosa [ 5]. Bladder mucosa has the obvious disadvantage of requiring a laparotomy to obtain it, and it can be difficult to manipulate the mucosa. On the other hand, buccal mucosa is readily available and much more robust; thus several groups are using it for strictures and for hypospadias repair, reporting their early experience with a short-term follow-up [ 6[7]–8]. This report describes our early experience of buccal mucosa in substitution urethroplasty.

Patients and methods

Thirty-nine patients (aged 23–59 years) underwent urethral reconstruction using a patch or tube graft of buccal mucosa harvested from the inner side of the cheek; the site of the stricture and type of the urethroplasty are shown in Table 1. Essentially, most patients underwent a patch graft of the bulbar urethra for an inflammatory stricture or one of unknown aetiology (≥2 cm long), and a few underwent a patch or tube graft in the penile urethra. All procedures were performed in one stage and all patients were followed for a mean of 3 years (range 2–5). They were evaluated with at least one post-operative ascending urethrogram and micturating cystogram during the follow-up.

Table 1.  The site of the stricture and type of urethroplasty in 39 patients Thumbnail image of

 The operative procedure involved exposing and preparing the urethra in the usual way. The buccal mucosa was harvested after submucosal infiltration of the cheek with 1 in 100 000 adrenaline, both to facilitate dissection and to reduce bleeding. Subdermal tissue was cleaned off the graft, which was then trimmed to size and sutured in place. The wound was closed in layers around an indwelling catheter that was left in place for 2–3 weeks and only removed after radiological evidence of satisfactory healing had been obtained on a peri-catheter urethrogram. Six months post-operatively, the patient was reviewed with a further ascending urethrogram, micturating cystogram and flow-rate study. Thereafter, urethrography was repeated only if symptoms or a deteriorating flow rate suggested a recurrent stricture.

Results

In the group undergoing patch urethroplasty, there were no short-term failures and only one recurrent stricture (3%) 18 months after surgery, although three other patients developed new strictures away from the urethroplasty site. Those with a tube graft urethroplasty in the penile urethra did not fare as well; nearly half the patients (five of 11) had recurrent strictures, all presenting at about 6 months after surgery. There were no post-operative problems at the donor site. The handling characteristics of buccal mucosa are better than for genital skin and bladder mucosa, and resemble those of a post-auricular Wolfe graft.

Discussion

From published reports, there have been no failures to date of urethroplasties using buccal mucosa [ 5[6][7]–8]. This extraordinary success rate is presumably due to the density of the subdermal plexus of buccal mucosa and thus the ease with which it obtains a blood supply from the graft site. The early results in this series with buccal mucosa are very satisfactory and other reports have suggested even better results.

 Our experience with skin flaps used as a patch or a tube in the same circumstances as those described here have been reported elsewhere and the general conclusion is that tube grafts are not as successful as patches [ 9, 10]; only preputial or penile skin flaps give satisfactory medium- and long-term results. How then do buccal mucosal grafts compare with genital skin flaps?

 The early results with the present patch grafts, with a mean follow-up at 3 years, are at least as good as the results with flaps [ 11]. Indeed, free grafts of buccal mucosa after 3 years appear substantially better than scrotal skin flaps at a similar follow-up. However, after the initial urethrogram, the present patients were followed using flow rates and symptoms, and so strictures larger than 10 F would not be detected; the same evaluations were used during the follow-up in previous reports [ 11]. The disappointing results with tube grafts mirror those of other tube grafts however they are constructed and suggest that a two-stage reconstruction of the penile urethra gives consistently better results than any one-stage technique with respect to urethral repair, notwithstanding the cosmetic result. Why tubed grafts or flaps do not perform as well as patches is unclear; tubed flaps should theoretically have a sufficient blood supply and thus some cause other than ischaemia seems most likely, although at present elusive. As recurrent strictures after flap formation tend to present after many months or years, the cause seems likely to be persistence or recurrence of the original problem, or otherwise due to an interaction between the flap and some constituent of the urine. Tubed free grafts probably fare less well than patches for the simple technical reason that the ‘bed’ is less reliable. The observation that problems with tubed free grafts generally present 6 months after surgery, i.e. early but not immediately, suggests that there is at least a partial ‘take’, perhaps dorsally on Buck’s fascia (of the corpora cavernosa) and ventrally in relation to the subcutaneous dartos layer, with a less reliable take laterally where there is a less stable vascular layer and compression from the post-operative dressing is less reliable. This would obviously be more likely in patients who had undergone previous surgery, as had all 11 patients in the present series.

 The results with buccal mucosa patches are at least as good at 3 years as those with preputial skin flaps within the same follow-up; as a result we have stopped using preputial and penile skin flaps in favour of buccal mucosal free grafts as the material of choice. The procedure for their use is much quicker and easier, and avoids adding the potential morbidity of raising the penile skin flap, i.e. torsion deformity of the penis, and from circumcision or other penile scarring, which is generally resented in our current patients. We reserve the flap procedure for those patients who have no satisfactory bed for a buccal mucosa graft or when some other local complication makes a free graft inadvisable.

 Theoretically, with the good and prompt healing of the donor site that follows harvesting of a buccal mucosa graft, a further graft could be harvested fairly quickly after the first procedure, which would give a further advantage to this technique. However, we have not had the opportunity to test this as yet.

 Finally, buccal mucosa also works well when exposed to the air as a patch graft in the first stage of a two-stage penile urethral reconstruction for conditions such as balanitis xerotica obliterans [ 12] or otherwise when a post-auricular Wolfe graft is unavailable for penile urethral reconstruction, e.g. after bilateral mastoidectomy. The ‘take’ is perhaps less reliable and there is a slight tendency to shrinkage of the graft when compared with a post-auricular Wolfe graft, but generally, as both tissues are in limited supply, the two techniques are complementary rather than alternatives.

 In conclusion, buccal mucosal urethroplasty is a very versatile technique which is quick and easy to perform, and widely applicable, but is best used as a patch rather than as a tube graft. When a circumferential urethral reconstruction is required, typically in the penile urethra, a staged reconstruction will generally be more reliable.

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