Management of the penile shaft skin in hypospadias repair: alternative to Byars' flaps

Effect of human urine on the tensile strength of sutures used for hypospadias surgery

INTRODUCTION

Hypospadias is the most common congenital condition affecting between 1 in 250 and 300 live births. Even in experienced hands, surgery to repair this congenital defect can have a high complication rate. Wound dehiscence is reported to occur in 5% and fistula formation in 6%-40% depending on technique. The choice of suture material has been shown to affect the complication rate although there is (currently) no consensus about the best suture material to use. Ideally, the sutures used for urethroplasty should be absorbable while maintaining sufficient mechanical strength to support the wounds until they are self-supporting and able to resist urinary flow. Previous studies have compared the effects of human urine on different suture materials especially catgut. However, catgut is now banned in Europe. Our study examined the tensile and breaking strength as well as rate of degradation for four types of absorbable suture now commonly used for hypospadias repairs in the UK.

MATERIAL AND METHODS

We examined the effect of prolonged storage (up to 27 days) in human urine on 6/0 gauge Vicryl, Vicryl Rapide, Monocryl and polydioxanone (PDS) sutures. These four suture materials are commonly used by the senior plastic consultant surgeon (NK) for hypospadias repairs. 50 mm sections of these suture materials were stored in either urine or saline as control. At specified time points, each suture was placed in a uniaxial load testing machine to assess the stress-strain profile and the mechanical load required to break the suture was measured.

KEY RESULTS

Exposure to urine reduced the tensile and breaking strength of all the suture materials tested. PDS demonstrated the greatest resilience. Vicryl Rapide was the weakest suture and degraded completely by day 6. Vicryl and Monocryl had similar degradation profiles, but Vicryl retained more of its tensile strength for longer.

CONCLUSIONS

There is a balance to be struck between the duration that a suture material must remain in any surgical wound and the risk that it causes foreign body effects. The results of this study suggest that Vicryl has the best characteristics for urethroplasty of the four suture materials tested.

Modified Byars' flaps for securing skin closure in proximal and mid-penile hypospadias

OBJECTIVE

The objective of this study was to describe a modification for skin closure combined with tubularized incised plate (TIP) urethroplasty in the repair of proximal and mid-penile hypospadias.

PATIENTS AND METHODS

The study included 47 patients with nondistal hypospadias who underwent a primary TIP procedure from September 2007 to May 2010. Meatal position was mid-shaft (n = 20), penoscrotal (n = 20), and scrotal (n = 7). The patients in the study were divided into two groups according to a modification in the technique of skin closure, which involved incising the prepuce vertically into two halves, then harvesting the dartos flap for covering the repair from one half, leaving the other preputial half to reconstruct the ventral skin without compromising its blood supply.

RESULTS

In the standard procedure (n = 19 patients), complications included glanular dehiscence (10.5%), glanular fistula (5%), urethrocutaneous fistula (10.5%), and skin complications (21%). In the modified procedure (n = 28 patients), complications included glanular dehiscence (7%) and glanular fistula (3.6%), but no skin complications or urethrocutaneous fistulae occurred.

CONCLUSION

The modified Byars' flaps is a useful alternative for skin closure during proximal and mid-shaft TIP urethroplasty, with fewer complications and acceptable cosmetic outcome.

The role of flaps and grafts in modern hypospadiology

The modern hypospadiologist must be proficient in the use of both vascularized flaps and free grafts. When choosing a repair for any given patient with hypospadias, one must consider the length of the urethroplasty, the presence and degree of ventral curvature and perhaps most importantly, the surgeon's own experience. Not all repairs are created equally and different complication rates and cosmetic outcomes can be seen among different surgeons utilizing the same technique. Each surgeon tends to infuse their own modifications to any given technique and many of these modifications go unreported. It is incumbent upon each surgeon to be familiar with a wide variety of techniques, which invariably includes the use of flaps and grafts. We present a spectrum of the uses of flaps and grafts in modern hypospadiology.

Tubularized incised plate (TIP) hypospadias repair

In the past 6 years TIP urethroplasty has become a preferred technique for distal hypospadias repair, and has also been used for proximal lesions and reoperations. In this article technical aspects of the procedure are described and published outcomes reviewed. TIP hypospadias repair has gained widespread acceptance because of its versatility, low complication rate and reliable creation of a vertically-oriented meatus.

Suture tracks after hypospadias repair

OBJECTIVE

To determine the incidence of suture tracks after hypospadias repair in which 6-0 chromic catgut was used to close the skin.

PATIENTS AND METHODS

From an initial series of 72 boys undergoing tubularized, incised-plate hypospadias repair, 23 (32%) were evaluated 1 year or more after surgery.

RESULTS

Of the 23 boys, 10 (43%) were found to have suture tracks. In all cases tracks were located on the ventral shaft skin and did not involve the glans or dorsal aspect of the circumcision. These tracks had not been detected at an earlier follow-up.

CONCLUSIONS

Tracks resulting from small absorbable sutures may not be apparent soon after surgery because the sinus is small. With time, the sinuses fill with keratin and thereby become obvious. The location of these tracks suggests that relative hypovascularity of ventral shaft skin may contribute to their development. The use of subcutaneous sutures may diminish the incidence of this minor complication of hypospadias surgery.

Tubularization of the incised urethral plate (Snodgrass procedure) for primary hypospadias surgery

OBJECTIVE

To evaluate the Snodgrass procedure for patients with hypospadias who have not undergone previous surgery and whose urethral plate is too narrow for tubularization alone.

PATIENTS AND METHODS

Thirty-two boys (mean age 18 months) underwent primary hypospadiac surgery performed by one surgeon (P.S.M.). Twenty-five boys had a distal hypospadias (coronal, subcoronal) and seven had a more proximal defect (penile shaft, penoscrotal). The operation involved incision of the urethral plate, which was then tubularized (Snodgrass procedure). The neourethra was then covered with a de-epithelialized pedicled dartos flap from the inner prepuce before glans and skin closure.

RESULTS

With a mean follow-up of 10 months (range 2-14) there were two complications; one child with a coronal hypospadias developed a fistula whist one with a penile shaft defect had complete breakdown of the neourethra. The cosmetic appearance in the other 30 patients is that of a normal slit-like terminal meatus.

CONCLUSION

Tubularization of the incised urethral plate is a safe advance in the surgery of hypospadias. We recommend it for both distal and proximal defects, in patients where the urethral plate is insufficient for tubularization alone.

Tubularized, incised plate urethroplasty for distal hypospadias

A technique is described for correction of distal hypospadias with minimal chordee by tubularizing the urethral plate. The key step is deep longitudinal incision of the plate, which allows for tubularization without the need for additional flaps. The resultant neourethra is functionally adequate and an excellent cosmetic result with a vertically oriented meatus is achieved. A total of 16 boys underwent the procedure with no case of meatal stenosis or fistula occurring during a median followup of 22 months.

Pedicled preputial patch in repair of minor penile chordee with or without hypospadias

A pedicled preputial patch is described which provides coverage of the ventral skin defect resulting from the release of the ventral skin during the repair of milder forms of hypospadias. The results have been reviewed in 32 consecutive cases, and have been shown to be satisfactory.

M inverted V glansplasty: a procedure for distal hypospadias

Minimal hypospadias is a commonly encountered anomaly. Duckett's innovative meatoplasty and glanuloplasty (MAGPI) procedure has become a standard operation for the correction of these lesions. Although usually successful, the complication of meatal retraction has been recognized at times after a MAGPI. The M inverted V glansplasty was designed to address the factors leading to meatal retraction and the abnormal glans shape sometimes seen after the MAGPI. The M inverted V glansplasty derives its name from the initial M-shaped incision that reconfigures during the course of the procedure into an inverted V. Of 16 boys followed for more than 2 months after an M inverted V glansplasty 14 have achieved good results. The remaining 2 cases had a definite degree of meatal retraction but because of the meatal and glanular relationships they have a good cosmetic result. The technique, its indications and its limitations are described.