EFFECT OF THE DEPTH AND WIDTH OF THE URETHRAL PLATE ON TUBULARIZED INCISED PLATE URETHROPLASTY

0022-5347/00/1642-0489/0

Vol. 164,489-491, August 2000 Printed in U.S.A.

THEJOURNAL OF UROLOGY@ Copyright 0 2000 by AMERICAN UROLOCICAL ASSOCIATION, INC.~

EFFECT OF THE DEPTH AND WIDTH OF THE URETHRAL PLATE ON TUBULARIZED INCISED PLATE URETHROPLASTY A. J. A. HOLLAND

AND

G. H. H. SMITH

From the Departments of Surgical Research and Paediatric Urology, New Children's Hospital, Royal Alexandra Hospital for Children, Westmead, Sydney, Australia

ABSTRACT

Purpose: We determined the effect of the depth and width of the urethral groove on tubularized incised plate urethroplasty for distal hypospadias. Materials and Methods: We retrospectively reviewed the records of 48 patients who underwent tubularized incised plate urethroplasty for distal hypospadias between September 1996 and December 1998 for whom preoperative evaluation of the depth and width of the urethral groove was available. Patients were examined by an independent clinician a median of 28 months after surgery when the neourethra was calibrated and urinary stream assessed. Results: Of the 48 patients 46 were available for clinical examination. The urinary stream was straight in 40 boys and angled in 8, while none sprayed. Urethral fistula developed in 6 patients with a urethral plate of less than 8 mm. wide (p = 0.001). The urethral groove was deep in 13 cases, moderate in 20 and shallow in 15. There were no differences among these 3 groups in regard to urinary stream direction or fistula rate. Of the boys with a shallow urethral groove 6 (40%)have a neourethral caliber of 6Fr or less versus 3 (15%)with a moderate and 0 with a deep groove. This difference was statistically significant (p = 0.028). Each patient in whom meatal stenosis developed had a shallow urethral groove. Conclusions: Urethral groove depth appears to influence neourethral caliber after tubularized incised plate urethroplasty. A shallow groove predisposes to a narrower neourethra and meatal stenosis subsequently. We observed no evidence that incising the urethral plate increases the final urethral diameter. Urethral fistula after tubularized incised plate urethroplasty was associated with an initially narrow urethral plate. KEY WORDS:urethra, hypospadias, fistula, abnormalities

In 1994 tubularized incised plate urethroplasty for distal hypospadias repair was initially reported in the literature.' Repair is based on the concept of hinging the urethral plate around a midline incision, enabling formation of a tubularized neourethra in the absence of a deeply grooved urethral late.^.^ An additional benefit of repair is the cosmetic outcome, since formation of a vertically orientated meatus provides the appearance of a normal circumcised penis.' A concern is that the relaxing incision of the urethral plate is equivalent to internal urethrotomy, which may scar rather than epithelialize, leading to neourethral stricture or meatal stenosis.'.* It may be expected that this problem would be potentially more significant in patients with a flat and narrow rather than a deeply grooved and wide urethral plate due to the greater degree of mobilization required. Therefore, we reviewed the records of patients at our institution after tubularized incised plate urethroplasty to determine the influence of the depth and width of the urethral plate on outcome with particular regard to the fistula rate, urinary stream adequacy, neourethral caliber and meatal stenosis.

MATERIALS AND METHODS

Formal approval for our clinical review was obtained from the ethics committee at our institution. We identified 48 patients in whom tubularized incised plate urethroplasty for Accepted for publication March 3, 2000.

distal hypospadias was performed by a single surgeon between September 1996 and December 1998. In each case the procedure was done on an outpatient basis. At surgery the appearance of the urethral groove was assessed according to its depth as shallow-almost flat, moderate-intermediate and deep-a marked cleft. After mobilizing the penile shaft skin and correcting any associated chordee we carefully assessed the distance between the true meatus and distal glans. In cases of an anterior penile or more distal meatus we performed tubularized incised plate urethroplasty but for more proximal hypospadias we used an alternative technique. The urethral plate was marked, judged by the glistening appearance of the plate epithelium versus the dull glans and shaft skin, and then measured before any relaxing incision was made in the glans. Measurement was made at the widest point of the urethral plate using a flexible sterile ruler. Based on this measurement patients were then divided into groups with a less than 8, between 8 and 10, and greater than 10 mm. wide urethral plate. The urethral plate was incised with scissors along its length from the true meatus to the distal margin, extending deeply down to the corporeal bodies, as described by Snodgrass. Glanuloplasty was done using 6-zero polyglycolic acid sutures, and the urethroplasty and penile skin were closed with 6 and 7-zero polyglactin. Patients were discharged home with a 6Fr catheter indwelling, which was removed between postoperative days 5 and 7. A minimum of 5 months postoperatively patients were followed by an independent clinician to

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490

EFFECT OF DEPTH AND WIDTH OF URETHRAL PLATE ON URETHROPLASTY TULE 1. Results of tubularized incised plate urethroplasty according to urethral plate depth Depth

No, Pts,

Median Age (range) Mos.

No. With Urethral Fistula

Shallow

15

14 ( 6 4 5 )

1 (7)

Moderate

20

10 (6-31)

3 (15)

Deep 13 14 (6-23) Overall 48 14 ( 6 4 5 ) * One patient required repeat meatotomy.

~

(%c)

Neourethra Caliber (Fr)

6 or Less, 8-10 12 or Greater, 6 or Less 8-10, 12 or Greater 6 or Less. 8-10 12 or Gre'ater, 6 or Less 8-10, 12 or Greater

2 (15) 6 (13)

assess the parental opinion of quality of the cosmetic result, urinary stream and neourethral caliber. The stream was evaluated by observing the patient while voiding, when possible. Neourethral caliber was measured by the gentle passage of a well lubricated sound of appropriate size on a scale of 6Fr or less, between 8 and 10Fr and 12Fr or greater.

N ~pts, ,

No. With Meatal Stenosis

6, 9 0, 3 16, 1 0. 13

2*

0, 9

0 2*

38, 1

0

shallow group 2 had a narrow urethral stream and prolonged voiding time, while 2 were asymptomatic. The stream was angled in 8 patients but straight in the remainder and none sprayed. There was no difference among groups in terms of the depth or width of the urethral plate and the urinary stream direction.

RESULTS

During the 2Yz-year period 48 patients underwent tubularized incised plate urethroplasty, including 46 examined by one of us (A. J. A. H.) during 4 months. Parents of the remaining 2 patients were interviewed by telephone and results were confirmed after contacting the local physician of the patient. The urinary stream was observed by the independent clinician in 28 cases and evaluation was based on parental assessment in the remaining 20. Median patient age a t surgery was 14 months (range 6 to 45) and median postoperative followup was 28 months (range 5 to 33). Preoperatively the meatal site was glanular in 40 cases, subcoronal in 7 and anterior penile in 1. Table 1shows results with respect to urethral plate depth, which was shallow, moderate and deep in 15, 20 and 13 patients, respectively. Table 2 lists the results of classification by urethral plate width, which was less than 8, between 8 and 10, and greater than 10 mm. in 11, 35 and 2 patients, respectively. Median patient age and range were not significantly different among these groups. Urethral fistula developed in 6 cases (13%).Although urethral plate depth was not associated with the fistula rate, all fistulas occurred in patients with a urethral plate of less than 8 mm. in maximal diameter (table 2). This difference was highly significant (chi-square test p = 0.01). The neourethra was 6Fr or less in 6 patients (40%)with a shallow, 3 (15%)with a moderate and 0 with a deep urethral groove. This difference was significant (exact chi-square test p = 0.028) and it appeared to be independent of urethral plate width. There was a general trend for the final mean neourethral caliber plus or minus standard deviation to be less than that of the width of the urethral plate determined at surgery, although the 2 measurements overlapped considerably (9.5 ? 0.9 and 8.4 ? 1.4 mm., respectively, see figure). Two patients with a shallow urethral groove required meatotomy, which was repeated in 1. Perioperatively maximal urethral plate width was less than 8 mm. in each case. Of the remaining 4 patients with a small neourethra in the TABLE2. Results Periop. Urethral Groove Width (mm.)

No, Pts,

Less than 8

11

8-10

35

Greater than 10 2 Overall 48 * One patient required repeat meatotomy.

of

DISCUSSION

Snodgrass initially described tubularized incised plate urethroplasty for distal hypospadias when the urethral groove was insufficiently deep to allow simple tubularization.' He reported that this technique enabled the urethra to be consistently tubularized with a diameter exceeding 10 to l 2 F r . l ~The ~ success of the technique has encouraged its application to proximal and revised hypospadias A clinical review of the records of 72 boys who underwent tubularized incised plate urethroplasty for distal and proximal hypospadias using calibration, urethroscopy and uroflowmetry failed to identify any evidence of neourethral strict ~ r eIn . ~previous series meatal stenosis was a complication of tubularized incised plate urethroplasty in 3 of 148 patients (2%)with distal and in 1 of 27 (4%)with proximal hypospad i a ~ .In ~ neither .~ study was an attempt made to correlate this complication with the initial appearance or width of the urethral plate. Our results indicate that urethral fistula as a complication of tubularized incised plate urethroplasty was exclusively associated with a maximal urethral plate width of less than 8 mm. before incision. Although urethral plate incision enables tubularization, we hypothesize that in this setting the underlying narrowness of the plate increases resistance to urinary flow in the neourethra, predisposing to fistula development. Our other positive findings were a significant difference in the incidence of meatal stenosis and smaller neourethral size in patients with a shallow versus a moderate or deep urethral plate. This observation implies that it is more problematic to create a urethra with a diameter of greater than 6Fr when the glans appears flat. Although the surgeon has some discretion when determining urethral plate width, if incisions are made too widely in the glans, closure becomes more difficult. These findings contrast with the absence of any difference in urinary stream direction among the 3 groups.

tubularized incised plate urethroplasty according to urethral plate width

Median Age (range) Mos.

No. With Urethral Fistula (%)

11 ( 7 4 5 )

6 (55)

13 (6-31)

0

20 (13-27) 14 ( 6 4 5 )

0 6 (13)

Neourethra Caliber (Fr) 6 or Less, 8-10 12 o r Greater, 6 or Less 8-10, 12 or Greater 6 or Less, 8-10 12 or Greater, 6 or Less 8-10, 12 or Greater

N ~ pts, . 6, 5 093 31, 1 0,2 0,g 38, 1

No. With Meatal Stenosis 2*

0 0 2*

EFFECTOFDEPTHANDWIDTHOFURETHRALPLATEONURETHROPLASTY

49 1

E

series implies that after tubularized incised plate urethroplasty patients with a shallow urethral plate are more likely to have a neourethra caliber of 6Fr or less. In addition, these boys also appear t o have a higher incidence of meatal stenosis than those with a moderate or deep urethral plate. Furthermore, patients with a urethral plate of less than 8 mm. wide were significantly more likely to have a urethral fistula. While we still believe that this technique provides good functional and cosmetic repair for distal hypospadias, surgeons must be aware of potential areas of difficulty in specific patient subgroups when an alternative technique may be associated with fewer complications.

5

Dr. J. Peat provided statistical advice on the interpretation of our results.

10.5

E

9.5

s

*

8.5 REFERENCES

7.5

6.5

Preoperative

Postoperative

Comparison of preoperative urethral plate width and postoperative neourethral caliber.

CONCLUSIONS

When considering optimal repair in hypospadias, the depth and width of the urethral plate should be assessed. Our

1. Snodgrass, W.: Tubularized, incised plate urethroplasty for distal hypospadias. J Urol, 151:414,1994 2. Rich, M. A,, Keating, M. A,, Snyder, H. M. et al: Hinging the urethral plate in hypospadias meatoplasty. J Urol, 142: 1551, 1989 3. Zaontz, M. R.: The GAP (glans approximation procedure) for glanular/coronal hypospadias. J Urol, 141:359,1989 4. Snodgrass, W.: Does tubularized incised plate hypospadias repair create neourethral strictures? J Urol, part 2, 162: 1159, 1999 5. Snodgrass, W., Koyle, M., Manzoni, G. et al: Tubularized incised plate hypospadias repair: results of a multicenter experience. J Urol, 156 839,1996 6. Snodgrass, W., Koyle, M., Manzoni, G. e t al: Tubularized incised plate hypospadias repair for proximal hypospadias. J Urol, 159 2129, 1998 7. Retik, A. B. and Borer, J. G.: Primary and reoperative hypospadias repair with the Snodgrass technique. World J Urol, 16 186,1998 8. Luo, C.-C. and Lin, J.-N.: Repair of hypospadias complications using the tubularized, incised plate urethroplasty. J Pediatr Surg, 3 4 1665,1999