A novel application of the lotus petal flap in high-risk perineal urethrostomy: principles and outcomes

Introduction: Perineal urethrostomy is a valuable technique in the management of complex anterior urethral strictures, as well as following penectomy or urethrectomy. Traditional techniques that employ perineal or scrotal skin flaps have documented failure rates of up to 30 per cent. Current techniques for salvage have only modest success, leaving patients few options other than permanent suprapubic catheter or cystectomy and ileal conduit formation. Results: We present a new method of perineal urethrostomy using perforator-based lotus petal flaps in cases which were high risk or unsuitable for traditional perineal urethrostomy techniques, or where traditional strategies had failed. All patients demonstrated continent voiding at a minimum of 22 months follow-up, with patency confirmed by flexible cystoscopy. No complications were encountered. Conclusion: Utilisation of lotus petal flaps in high-risk cases of perineal urethrostomy will lead to significant improvements in patient outcomes. The availability of larger amounts of soft tissue coverage will obviate the need for compromise on either resection of involved urethra, or calibre and inset of urethrostomy. This will subsequently minimise the rates of failure, reduce the requirement for urinary diversion procedures and lead to improved quality of life.


Introduction
Perineal urethrostomy (PU) is a valuable technique in the management of anterior urethral strictures.
It is indicated in situations where urethroplasty is unable to be performed; as a salvage for failed urethroplasty, or as the first step of a staged urethroplasty. 1 It is also utilised following penectomy or urethrectomy to avoid the need for a permanent suprapubic catheter. 2 PU allows patients to maintain continent voiding, and has been shown to maintain patient quality of life. 3 Traditional operative techniques, as described by Johanson and Blandy, incorporate perineal and scrotal skin flaps to allow the urethra to be mobilised without excessive tension, minimising rates of stenosis. 4,5 Failure of PU has been defined as any patient requiring post-operative instrumentation, and the reported rate of failure ranges from 21.6-30 per cent. 3,[6][7][8] Multiple factors can contribute to failure of perineal urethrostomies. These include recurrence of the underlying pathology (such as urethral cancer or lichen sclerosus), inadequate debridement of involved proximal urethra, wound infection, or excessive tension at the anastomosis. 9 Radiotherapy, 7 prior failed urethroplasty, and a traumatic or infective stricture aetiology 3 have been shown to increase risk of PU failure.
Currently used salvage techniques for failed PU include repeated local random-pattern flaps 10,11 and buccal mucosal 12 or split-thickness skin grafts, 9 with only modest success being reported. The only alternative after failed revision PU is urinary diversion, such as supra-pubic catheterisation or ileal conduit formation. 9 Our aim was to develop a technique that enabled creation of the urethrostomy to an adequate calibre using vascularised tissue based on known regional perforator anatomy, sufficient to permit tension-free closure, in cases that would be high risk or unsuitable for traditional PU methods.

Methods
Following general anaesthesia, the patient is placed in the lithotomy position. Perforating vessels of the internal pudendal system are identified using handheld Doppler ultrasound. Prophylactic intravenous antibiotics are administered prior to incision, and the urethra is debrided to healthy viable tissue.
The proximal urethra is spatulated and absorbable stay sutures are inserted.
The distance from the perineal skin to the urethra is measured, and the lotus petal flap is marked incorporating the previously identified perforating vessels (Figure 1).

Fig 1. Preoperative markings following perforator identification using hand-held Doppler ultrasound
The initial incision is made and then the flap is raised in a supra-fascial plane from distal to proximal in the manner previously described, with identification and dissection of the perforating vessels ( Figure 2).

Results
To date, this technique has been used in three patients through our institution. Their cases are summarised in Table 1 The lotus-petal flap was first described in 1996 for use in the reconstruction of vulvo-vaginal defects. 15 Since that initial description, it has been used in a range of indications for wounds of the perineum, including scrotal and perianal defects. 16,17 In their initial description, Yii and Niranjan    10 It utilises a local random-pattern flap that

Conclusion
Utilisation of lotus petal flaps in high-risk cases of perineal urethrostomy will lead to significant improvements in patient outcomes. The availability of larger amounts of soft tissue coverage will obviate the need for compromise on either resection of involved urethra, or calibre and inset of urethrostomy. This will subsequently minimise the rates of failure, and reduce the requirement for urinary diversion procedures.