Onlay Island Flap in the Repair of Mid and Distal Penile Hypospadias Without Chordee

0022-534 7/87 /1382-0376$02.00/0 Vol. 138, August

THE JOURNAL OF UROLOGY

Copyright © 1987 by The Williams & Wilkins Co.

Printed in U.S.A.

ONLAY ISLAND FLAP IN THE REPAIR OF MID AND DISTAL PENILE HYPOSPADIAS WITHOUT CHORDEE JACKS. ELDER,* JOHN W. DUCKETTt

AND

HOWARD M. SNYDER

From the Division of Urology, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania

ABSTRACT

The onlay island flap is a variation of the transverse preputial island flap for hypospadias repair.

It is useful in patients without fibrous chordee whose meatus is mid penile or subcoronal. This technique was used in 50 patients and the results were compared to those of 34 patients undergoing the Mathieu meatal-based flap (flip-flap) during the same period. The cosmetic results with the onlay island flap were quite satisfactory and the complication rate was 6 per cent, which was identical to that observed with the Mathieu repair. The onlay island flap is applicable particularly in patients with mid shaft hypospadias without chordee, if the meatus is too proximal for a Mathieu repair and in patients with distal penile hypospadias with deficient ventral skin. J. Ural., 138: 376-379, 1987 Approximately 15 per cent of the boys with hypospadias have a mid or distal shaft meatus at least 1 cm. proximal to the corona without associated fibrous chordee. 1 Several techniques may be applied in the repair of this particular form of hypospadias. The meatal-based vascularized flip-flap (Mathieu repair)2-5 is the most popular today. Alternatively, the meatalbased flap may be tubularized and brought through a glans channel (the Mustarde repair). 6 If the meatus is less than 1 cm. from the corona and sufficiently compliant an extended meatoplasty and glanuloplasty procedure may be performed. 1- 9 Finally, the skin distal to the hypospadiac meatus may be tubularized (the King repair) .10 Well vascularized proximal ventral skin is necessary for success in the Mathieu procedure in patients with mid shaft or distal hypospadias. When there is thin or deficient ventral skin, a flip-flap procedure is precarious. The onlay transverse preputial island flap was developed for this particular situation. As a variation of the standard tubularized preputial island flap 11 it represents a logical sequence in the assessment of the hypospadias anomaly at the operating table.

A ventral transverse preputial flap 10 to 12 mm. wide then is marked out and mobilized as an island flap based on the axial blood supply (fig. 2). Since this flap will serve as an onlay to the urethral plate, it need not be as wide because it is not tubularized. The precise size of the onlay is not critical, since it will be trimmed and fashioned to fit the urethral strip for the appropriate urethral size. The onlay flap then is rotated around to the ventrum of the penis. The onlay is approximated parallel to the urethral plate and the edges are sutured together with a running 6 or 7-zero polyglycolic acid suture. The onlay flap is now tailored to fit.

ONLAY ISLAND FLAP TECHNIQUE

A traction suture is placed through the glans. The proposed incision is marked out 8 mm. proximal to the corona dorsally and extending a few mm. proximal to the meatus on the ventral shaft (fig. 1). After infiltration of 1 per cent lidocaine with 1:100,000 epinephrine for hemostasis, the incision is made and the penile skin is separated from the corporeal bodies in the avascular plane between Buck's fascia and the dartos fascia. If penile torsion or significant skin chordee is present, the penile skin may need to be mobilized to the penoscrotal junction. After determining that there is no fibrous chordee with artificial erection, the strip of urethral plate is developed. Two parallel incisions are made to the tip of the glans. The width of this strip is 6 to 8 mm. and it extends onto the glans at the edge of the deep meatal groove. The glans should be flattened as these glans incisions are made. The medial edges of the strip should not be mobilized. The proximal meatus should be opened back to good spongiosum, excising the thin ventral urethra back as far as the penoscrotal area if needed. Accepted for publication February 18, 1987. Read at annual meeting of American Urological Association, New York, New York, May 18-22, 1986. * Current address: Division of Urology, Rainbow Babies and Children's Hospital, 2101 Adelbert Rd., Cleveland, Ohio 44106. t Requests for reprints: Division of Urology, Children's Hospital of Philadelphia, 34th St. and Civic Center Blvd., Philadelphia, Pennsylvania 19104. 376

B

D

FIG. 1. Schematic illustration of onlay island flap. A, mid penile hypospadias or distal shaft meatus without chordee and urethral plate intact. B, parallel incision onto glans from dorsal urethral strip 8 mm. wide. Island flap outlined from inner prepuce 10 to 12 mm. wide. C, island flap mobilized to ventrum and proximal urethra cut back to well vascularized spongiosum. D, 1 side of onlay flap sutured with running 6 or 7-zero polyglycolic acid. Interrupted sutures approximate proximal aspect of flaps to urethra to fashion flap to caliber of 12 to 14F with bougie a boule. E, opposite side is closed with running suture and flap is trimmed to appropriate size. F, glans wings are closed to form apical meatus. Skin cover is variable. Reprinted with permission from Duckett, J. W.: Hypospadias. In: Adult and Pediatric Urology. Edited by J. Y. Gillenwater, J. T. Grayhack, S.S. Howards and J. W. Duckett. Chicago: Year Book Medical Publishers, Inc., 1987.

ONLAY ISLAND FLAP IN REPAIR OF HYPOSPADIAS WITHOUT CHORDEE

377

Fm. 2. Intraoperative photographs of onlay island flap procedure. A, mid shaft meatus with apparent chordee. B, mobilization of skin proximal to urethral meatus with cutback of ventral urethra to good spongiosum. Artificial erection straight. C, transverse inner preputial island flap developed, rotated to right side and sutured along urethral strip (7 mm. wide). Scissors are used to trim excess length and tailor flap to avoid diverticulum formation. D, onlay in place with bougie a boule 12F calibrating proximal meatus. E, completion of repair with meatus at apex. Drainage tube (6F silicone stent) is used to drain bladder. Photographs courtesy of LTI Medica®/Lester V. Bergman.

To turn the corner around the proximal meatus, interrupted sutures are placed around the horseshoe. Bougies a boule are used to calibrate the proximal anastomosis to 12 to 14F. After the interrupted sutures are placed, a running inverting stitch is used for the opposite edge of the flap. Care is taken to leave a generous 12 to 14F meatus at the tip of the glanular groove with a well vascularized flap. The glans wing flaps then are wrapped around the neourethra, sewn to the edge of the onlay flap with interrupted 7-zero chromic sutures and approximated in the midline with interrupted 6-zero polyglycolic acid or chromic sutures to create a glanular meatus. After the anastomosis is completed, a saline solution is injected into the distal urethra with an 8F feeding tube while maintaining perinea! compression to examine the integrity of the anastomosis. The dorsal prepuce is split to provide ventral skin coverage. A midline ventral skin closure is preferred. Torsion of the penis may occur with a rotational island flap and care must be taken to mobilize the base of the pedicle on the opposite side to avoid this torsion. A 6F silicone tube is passed through the repair into the bladder, sutured through the tube to the glans with 5-zero polypropylene suture and allowed

to drain into a diaper. A compressive dressing then is applied. Recently, a silicone foam elastomer has been used. 12 The dressing is left in place for 3 to 5 days and the urethral stent is removed after 10 to 14 days. RESULTS

During a 32-month period 50 patients underwent the onlay island flap repair. To assess the efficacy of this type of reconstruction, the results were compared to those of 34 patients undergoing the Mathieu repair during this same period. With 2 exceptions, all procedures were performed either as an outpatient (50 patients, 60 per cent) or with a 1-night stay (32 patients, 38 per cent). Optical magnification between 2 and 3.5 times was used routinely. In the onlay island flap group patient ages ranged from 7 months to 27 years (median 16 months), whereas in the Mathieu repair group patient ages ranged from 6 months to 16 years (median 17 months). In general, the repair was performed when the child was 6 to 9 months old or in older children at the time of referral. The original location of the meatus is shown in table 1. Those patients undergoing the onlay island flap tended to have a more proximal meatus than

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ELDER, DUCKETT AND SNYDER

those undergoing the Mathieu procedure. In none was fibrous chordee present and many had apparent chordee before skin mobilization. Table 2 summarizes the complications in both patient groups (6 per cent in each). In the onlay group complications included necrosis of the island flap that was repaired successfully 9 months later by a repeat onlay island flap in 1 patient, a fistula that was repaired 6 months later in 1 and significant incrustation of the urethral stent requiring saline irrigation in 1. Of the patients undergoing the Mathieu procedure 1 had meatal stenosis that required operative correction, and in another the stent retracted into the bladder and required cystoscopic removal with anesthesia. No fistulas developed. DISCUSSION

The onlay island flap is applicable particularly in patients with mid shaft hypospadias without fibrous chordee in which the meatus is too proximal for a Mathieu repair and in those with distal penile hypospadias with thin ventral skin. In addition, the procedure may be used in patients with mid penile hypospadias and mild chordee that can be corrected without dividing the urethral plate, for example by dorsal plication. In contrast, the Mathieu procedure should be used in patients with distal penile hypospadias without chordee in which the proximal ventral skin is well vascularized.13 We believe that the onlay island flap provides an excellent cosmetic result with no more morbidity than the popular Mathieu procedure. One might compare the complication rate of 6 per cent using the onlay to the complication rate of 10 to 15 per cent with the tubularized transverse preputial island flap that is used for more severe hypospadias with chordee. 9 TABLE

1. Original location of urethral meatus Onlay Island Flap(%) 4 18 27 1

Coronal Subcoronal Mid penile Penoscrotal Totals

TABLE

An example in which the onlay island flap was used is shown in figure 3. Figure 3, A demonstrates an example of subcoronal hypospadias with divergent spongiosum tissue proximal to the meatus. When the penile skin is dropped back, the ventral urethra is noted to be quite thin (fig. 3, B). A poorly developed distal urethra has been noted commonly in our patients undergoing the onlay island flap. By incising the urethra in the ventral midline back to well vascularized spongiosum tissue, a more reliable anastomosis may be performed. The onlay island flap is similar to the Hodgson II repair. 14 However, in the latter procedure a vertical flap of dorsal penile skin is transposed ventrally with a buttonhole technique. As originally described, this results in a urethral meatus that is continuous with ventral penile skin, although the distal flap may be detached to permit incorporation into the glans. Turner-Warwick also mentioned an onlay principle for anterior urethral strictures, 15 and Shapiro has recommended a free onlay graft with preputial skin. 16 However, we believe that the onlay island flap has better vascularity and fewer complications. Nearly all of these procedures have been performed on an outpatient basis. Several aspects of management deserve emphasis. The use of epinephrine in a 1:100,000 solution for hemostasis allows these repairs to be performed in a relatively bloodless field, particularly for a more precise glanular anastomosis. A dorsal penile block with bupivacaine is performed after anesthetic induction. Operative erections are avoided and the child awakens from anesthesia without discomfort. The postoperative analgesic requirements seem to be less. The silicone foam dressing 12 provides good compression for the repair and remains for 3 to 5 days. The silicone urethral stent permits ease of care by the family at home; there are no drainage tubes or bags to kink and bladder spasms are minimal.

(8) (36) (54) (2)

50

Mathieu(%) 4 (12) 27 (79) 3 (9) 0

34

2. Complications: onlay versus Mathieu Onlay (50 pts.)

Fistula Flap necrosis Meatal stenosis Stent complications Totals(%)

Mathieu (34 pts.)

1 1

0 0

0

1

1 1

3 (6)

2 (6)

REFERENCES

1. Juskiewenski, S., Vaysse, P., Guitard, J. and Moscovici, J.: Traitement des hypospadias anterieurs. Place de la balanoplasie. Chir. Ped., 24: 75, 1983. 2. Mathieu, P.: Traitement en un temps de l'hypospadias balanique et juxtabalanique. J. Chir., 39: 481, 1932. 3. Devine, C. J., Jr.: Chordee and hypospadias. In: Urol_ogic Surgery, 3rd ed. Edited by J. F. Glenn. Philadelphia: J.B. Lippincott Co., chapt. 76,p. 775, 1983. 4. Kim, S. H. and Hendren, W. H.: Repair of mild hypospadias. J. Ped. Surg., 16: 806, 1981. 5. Gonzales, E. T., Jr., Veeraraghavan, K. A. and Delaune, J.: The management of distal hypospadias with meatal-based, vascularized flaps. J. Ural., 129: 119, 1983. 6. Belman, A. B.: The modified Mustarde hypospadias repair. J. Ural., 127: 88, 1982.

FIG. 3. Patient with distal penile hypospadias. A, note proximal divergence of spongiosum tissue. B, after drop back of penile skin, deficient ventral urethra is apparent (arrow). Divergent spongiosum is outlined. Iris scissors are in distal urethra to incise back to well vascularized tissue.

ONLAY ISLAND FLAP IN REPAIR OF HYPOSPADIAS WITHOUT CHORDEE 7. Duckett, J. W.: MAGPI (meatoplasty and glanuloplasty): a procedure for subcoronal hypospadias. Urol. Clin. N. Amer., 8: 513, 1981. 8. Duckett, J. W.: Techniques of hypospadias repair. J. Urol., part 2, 133: 284A, abstract 682, 1985. 9. Duckett, J. W.: Hypospadias. In: Campbell's Urology, 5th ed. Edited by P; C. Walsh, R. F. Gittes, A. D. Perlmutter and T. A. Stamey. Philadelphia: W. B. Saunders Co., vol. 2, sect. XIII, chapt. 47, p. 1969, 1986. 10. King, L. R.: Hypospadias-a one-stage repair without skin graft based on a new principle: chordee is sometimes produced by the skin alone. J. Urol., 103: 660, 1970. 11. Duckett, J. W.: The island flap technique for hypospadias repair. Urol. Clin. N. Amer., 8: 503, 1981. 12. De Sy, W. A. and Oosterlinck, W.: Silicone foam elastomer: a

13. 14.

15. 16.

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significant improvement in postoperative penile dressing. J. Urol., 128: 39, 1982. Gibbons, M. D. and Gonzales, E. T., Jr.: The subcoronal meatus. J. Urol., 130: 739, 1983. Hodgson, N. B.: Hypospadias and urethral duplications. In: Campbell's Urology, 4th ed. Edited by J. H. Harrison, R. F. Gittes, A. D. Perlmutter, T. A. Stamey and P. C. Walsh. Philadelphia: W. B. Saunders Co., vol. 2, sect. XII, chapt. 45, p. 1566, 1979. Turner-Warwick, R.: The use of pedicle grafts in the repair of urinary tract fistulae. Brit. J. Urol., 44: 644, 1972. Shapiro, S. R.: Free graft patch 1-stage procedure to repair penile hypospadias unsuitable for the flip-flap procedure: indications and experience. J. Urol., 136: 433, 1986.