Tubularized Incised Plate "Snodgrass" versus Mathieu Technique in treatment of distal hypospadias

Transcription

1 Kasr El Aini Journal of Surgery VOL., 11, NO 1 January Tubularized Incised Plate "Snodgrass" versus Mathieu Technique in treatment of distal hypospadias Mohamed Mahmoud Mohamed Ahmed MD & Osama Abdel Wahab MD* Departments of General Surgery and Urology*, Faculty of Medicine, Benha University ABSTRACT This study was designed to evaluate outcome of the Meatal-based Flap "Mathieu" Technique versus Tubularized Incised Plate "Snodgrass", for distal hypospadias repair in children, the study included 34 children with mean age of 17.5±4.8 months and had distal hypospadias with good prepucial hood and mild chordee (<30 ). Patients were randomly classified into two groups. Group 1 underwent Snodgrass technique with spongeoplasty (S group; n=17), while group 2 underwent Mathieu technique (M group; n=17). Operative time and times till transurethral catheter removal, and till hospital discharge, the frequency of postoperative (PO) complications were reported and compared. At 6-months postoperatively, parents were inquired about their satisfaction about the cosmetic appearance of the penis and the shape of the uretheral meatus, the mean operative time, durations of urethral stenting and of hospital stay showed non-significant difference between both procedures. Three patients developed urethrocutaneous fistula; 2 in group2 and one in group1 and 4 patients, 2 in each group had meatal stenosis with significantly higher success rate in group 1 (82.4%) compared to group2 (76.5%). Patients developed fistula had redo Snodgrass with dartos fascia coverage, irrespective of the first technique, 6 months after the initial repair and all of the 3 cases had successful redo surgery. One patient had meatal stenosis in group2 that required operative slit-opening of the stenosed meatus, while the other 3 patients responded to frequent dilatation. As regards parents' satisfaction, the frequency of high satisfaction scores and the total satisfaction score were significantly higher in S group compared to M group, it could be concluded that Snodgrass technique with spongeoplasty was advantageous with significantly higher success rate and better cosmetic results inducing significantly higher parents' satisfaction rate. Moreover, Snodgrass technique with dartos fascia coverage is applicable for redo cases with high success rate. Keywords: hypospadias, " Snodgrass", "Mathieu", urethral plate. INTRODUCTION Hypospadias is a congenital abnormality caused by incomplete development of urinary meatus, in which the meatus is opened on the ventral side of penis instead of apex of glans. Its incidence rate is reported to be about 1 in 300 male live births. Hypospadias is divided into three types of posterior, middle, and anterior, regarding the position of meatus. In anterior type, meatal orifice opens either on distal penile (1, 2) shaft, on corona, or under the glans, A variety of surgical techniques for hypospadias repair have been described over several decades, however, there is no single, universally applicable technique for hypospadias repair. Command of a technically straightforward repair with few complications and proven success and versatility in a reasonable range of hypospadias defects are desired goals. Several well-established techniques exist for the repair of all hypospadias defects, (3) One-stage repair has become the accepted procedure of choice. Since Duckett (4) reported transverse preputial tubularized flap urethroplasty, one-stage repair has been gaining in popularity with several new one-stage techniques being mentioned. Current popular one-stage procedures are transverse island flap onlay and tubularized incised plate urethroplasty, as first reported by Elder et al. (5) and Snodgrass (6), respectively. About 80% of patients with hypospadias have a meatus in a coronal or subcoronal position. The perimeatal-based flap urethroplasty is commonly used for the primary correction of distal hypospadias. The most frequent complications after hypospadias repair are urethrocutaneous fistulae and meatal stenosis, which have been reported in up to 21% of patients (7).

2 Kasr El Aini Journal of Surgery VOL., 11, NO 1 January The Snodgrass tubularized incised plate urethroplasty has become a popular technique for primary repair of middle and anterior hypospadias. Since the procedure carries low complication rates and yields favourable cosmetic results in distal and mid-shaft hypospadias, the procedure has been increasingly applied (8). The present prospective comparative study aimed to evaluate the outcome of two of urethroplasty techniques; namely the Meatalbased Flap "Mathieu" Technique and Tubularized Incised Plate "Snodgrass", for distal hypospadias repair in children. PATIENTS & METHODS The study was conducted at Departments of General Surgery and Urology, Benha University Hospital since Jun 2007 till Jan 2009 to allow a minimum follow-up period of 6 months for the last case operated upon. After approval of the study protocol by the Local Ethical Committee and obtaining fully-informed parents' written consent; 34 children with distal hypospadias, good prepucial hood, mild chordee (<30 ), and adequate urethral plate (width of urethral plate >6 mm labeled as well formed, 4-6 mm as narrow, and <4 mm as inadequate) were enrolled in the study. Patients were randomly divided into two equal groups according to the surgical technique assigned for each group, either Mathieu (Mathieu group) or Snodgrass (Snodgrass group). All children underwent complete physical examination with special regard to the presence of other congenital anomalies and preoperative laboratory investigation. Patients had previous hypospadias repair, had circumcised, had other urogenital anomalies, with inadequate length of urethral plate, moderate-to-severe chordee, severe hypospadias requiring complex repair were excluded of the study. All surgeries were conducted under general anesthesia with endotracheal intubation, 3rd generation cephalosporin were injected intravenously with induction of anesthesia in a dose of 50 mg/kg body weight and assigned to be continued for 72 hours postoperatively. Surgical techniques A) Mathieu Technique was conducted as shown diagrammatically in Figure (1) (9) with operative detailed as shown in Figure (2 A- F). B) Snodgrass Technique was conducted as shown diagrammatically in Figure (3) (9). A collar incision was made and chordee was completely released by degloving of the penis. Parallel longitudinal incisions were made on either side of the urethral plate up to the level where edges of glans groove starts converging. Urinary meatus was included in the incision. Glanular wings were raised. The plate was then incised in the midline from meatus to the glans. Incision was not extended to the tip of the glans, to prevent subsequent meatal stenosis. Deep incision was taken to divide all transverse webs and expose the corporal bodies. Mobility of the epithelial strips created by longitudinal incision of the plate was confirmed so as to relieve meatal stenosis. The urethral plate was tubularized over uretheral catheter no. 8 with vicryl 6-0 interrupted vicryl sutures. Splayed out corpus spongiosum on either side of the urethral plate was mobilized and sutured over the tubularized urethra. Incision was given over the inner aspect of prepuce and subcutaneous tissue was separated from the skin using sharp dissection and was sutured over the neourethra with vicryl 6-0. Glans wings were sutured in two layers with interrupted vicryl 5-0 suture. Rotated skin flaps were sutured in the midline. To avoid crossing over of suture lines, it was arranged in the following order; the neourethral suture line was in the midline, the de-epithelialized flap suture line was laterally and rotated skin was trimmed and then approximated in midline using vicryl 5-0 interrupted sutures, (Fig. 4 A-E). Operative time and time till transurethral catheter removal, first change of dressing and hospital discharge were determined for both groups and compared. The frequency of uretheral fistula, wound dehiscence, meatal stenosis and total success rate were also compared. At 6- months postoperatively, parents were inquired about their satisfaction about the cosmetic appearance of the penis and the shape of the uretheral meatus. Parents' satisfaction was graded as 3=very satisfactory or near normal appearance, 2=satisfactory, 1=unsatisfactory.

3 Kasr El Aini Journal of Surgery VOL., 11, NO 1 January Statistical analysis Obtained data were presented as mean±sd, ranges, numbers and ratios. Results were analyzed using paired t-test and Chi-square test. Statistical analysis was conducted using the SPSS (Version 10, 2002) for Windows statistical package. P value <0.05 was considered statistically significant. RESULTS The study included 34 children with distal hypospadias with mean age of 17.5±4.8; range: 9-28 months. Mild chordee were reported in 25 patients (73.5%), while the other 9 patients (26.5%) showed no detectable chordee. Well formed urethral plate was detected in 23 patients (67.6%) and 11 patients (32.4%) had narrow urethral plate and were enrolled in M group. There was non-significant difference between both groups as regards preoperative data, (Table 1). All patients had smooth intraoperative course and no cases were postponed or cancelled. Mean operative time was non-significantly (p>0.05) shorter in M group compared to S group. On contrary, duration of urethral stenting and duration of hospital stay were non-significantly (p>0.05) shorter in S group compared to M group, (Table 2). Throughout the follow-up period, 3 patients developed urethrocutaneous fistula; one in S group and 2 in M group and 4 patients had metal stenosis, 2 in each group for a total complication rate of 20.6% with non-significantly (X2=0.382, p>0.05) higher success rate in S group (82.4%) compared to M group (76.5%), (Fig. 5). Patients who developed fistula had fistula repair with dartos flap coverage, irrespective of the first technique, 6 months after the initial repair and all of the 3 cases had successful redo surgery. Patient who had meatal stenosis underwent frequent at-home dilatation using the tip of medical thermometer after application of corticosteroid/local anesthetic gel to facilitate dilatation. However, unfortunately one patient of M group required slit-opening of the stenosis followed by frequent dilatation to achieve appropriate sized meatal orifice, (Table 3). At 6-months postoperatively, 20 parents were very satisfied with appearance of the penis and the configuration of the meatal opening, (Fig. 6 a & b), 5 parents were satisfied, while 9 parents were unsatisfied; 4 of them were unsatisfied because of the concurrent complications that required redo surgery, the other 5 were unsatisfied by the rounded meatal configuration resultant after Mathieu technique. The frequency of high satisfaction scores and the total satisfaction score were significantly higher in S group compared to M group, (Table 4, Fig. 5) Table (1): Patients preoperative data S group M group Total Age (months) 17.2±5 (9-28) 17.8±4.6 (9-26) 17.5±4.8 (9-28) Degree of No 4 (23.5%) 5 (29.4%) 9 (26.5%) chordee Mild 13 (76.5%) 12 (70.6%) 25 (73.5%) Urethral Well formed 17 (100%) 6 (35.3%) 23 (67.6%) plate Narrow 0 11 (64.7%) 11 (32.4%) Data are presented as means±sd, numbers; ranges & percentage are in parenthesis Table (2): Operative and immediate postoperative data S group M group Statistical analysis (n=17) (n=17) t p Operative time (minutes) 105.6± ± >0.05 (75-120) (80-120) Duration of stenting (days) 3.9±1 4.2± >0.05 (3-5) (3-5) Hospital stay (days) 4.9±0.9 (4-6) 5.2±0.8 (4-6) >0.05 Data are presented as means±sd; ranges are in parenthesis

4 Kasr El Aini Journal of Surgery VOL., 11, NO 1 January Table (3): Immediate postoperative complication and its management No Present Urethrocutaneous S group 16 (94.1%) 1 (5.9%) fistula M group 15 (88.2%) 2 (11.8%) Meatal stenosis S group 15 (88.2%) 2 (11.8%) M group 15 (88.2%) 1 (5.9%) Data are presented as numbers; percentages are in parenthesis Postoperative Management Management Outcome Redo Snodgrass with Succeeded dartos flap coverage 6- m later Frequent at home dilatation 1 (5.9%) Operative slit opening after failure of at home dilatation Succeeded Succeeded Table (4): Parents' satisfaction data about cosmetic appearance S group (n=17) M group (n=17) Frequency Score=3 12 (70.6%) 8 (47.1%) Score=2 3 (17.6%) 2 (11.8%) Score=1 2 (11.8%) 7(41.1%) Statistical X 2 = analysis p= <0.01 Total score Mean±SD 2.6± ±0.9 Statistical t= analysis p= =0.027 Data are presented as means±sd, numbers; ranges & percentage are in parenthesis Fig. (1)

5 Kasr El Aini Journal of Surgery VOL., 11, NO 1 January Fig. (2a) Fig. (2b) Fig. (2c) Fig. (2d) Fig. (2e) Fig. (2f) Math-2-PO

6 Kasr El Aini Journal of Surgery VOL., 11, NO 1 January Fig. (3) Fig. (4a) Fig. (4b) Fig. (4c) Fig. (4d) Fig. (4e)

7 Kasr El Aini Journal of Surgery VOL., 11, NO 1 January Snod -4-PO DISCUSSION The present study aimed to evaluate the outcome of two techniques for repair of distal hypospadias as regards functional and aesthetic results; both techniques were surgically feasible and showed non-significant difference as regards operative time, duration of urethral stenting and hospital stay. Such findings go in hand with previous studies (10) evaluating each technique separately or in comparison. The reported success rate despite being lower with Mathieu technique, the difference was statistically non-significant; 82.4% with Snodgrass technique versus 76.5% with Mathieu technique. These low success rates for both techniques could be attributed to the small-sized patients samples studied, as only 3 cases of fistula were reported 2 in M group and one in S group. The reported figure for success and fistula rate after Snodgrass technique could be attributed to spongioplasty conducted as additional coverage for the neo-urethra prior to skin closure and goes in hand with Sarhan et al. (11) who reported overall success rate, after Snodgrass urethroplasty, of 81.4% and fistula rate of 9.4% and concluded that a significantly better outcome is achieved with distal hypospadias, covering the neourethra with the mobilized corpus spongiosum (spongioplasty) or a flap and with Abolyosr (12) who reported no urethrocutaneous fistula after Snodgrass technique. He concluded that the neouretha covering is an integral part of the Snodgrass hypospadias repair and a dorsal well vascularized double-layered dartos flap is a good choice for preventing urethrocutaneous fistula formation. In support of the concept of neourethral coverage for prevention of fistula formation, Mahmoud et al. (13) assessed the results of onestage repair of anterior hypospadias using modified Mathieu procedure; the modifications used were interrupted inverting sutures of 5/0 polyglycolic acid for urethroplasty; neourethra covering with subcutaneous (dartos) pedicle flap and dorsal/anterior meatotomy for meatal stenosis and reported a complication rate of 11.6% with 3% urethrocutaneous fistula rate. Also, Ghanem & Nijman (14) reported an overall success rate of 88% and fistula rate of 8% after proximal penile hypospadias using a one-stage TIP urethroplasty with a dorsal dartos to cover the neourethra ventrally. The three patients who had fistula underwent fistula repair using Snodgrass technique and dartos flap coverage and all of the three fistula cases were successfully repaired. The reported success using such policy was in line with Shehata et al. (15) who reported that the advantages of a procedure based on the TIP principle for the treatment of recurrent penile mega fistula are numerous; the procedure is easy to perform and can be successfully used to treat recurrent urethrocutaneous fistula in carefully selected cases with an acceptable (9%) recurrence rate. Also, Ozturk (16) tried dartos flap coverage in urethrocutaneous fistulas repair and

8 Kasr El Aini Journal of Surgery VOL., 11, NO 1 January reported successful repair of the fistula on the first attempt in all patients. Parents' satisfaction rates and scores were concerning the aesthetic appearance of the penis and meatus were significantly higher with Snodgrass technique compared to Mathieu technique and this result supported that reported by Al-Saied & Gamal (8) who found that all children who underwent TIP urethroplasty were able to void with a single straight urinary stream in a forward direction, and have a rounded glans with vertical slit- like terminal glandular meatus. All families were happy with penile aesthetic appearance. Duration of urethral stenting and its impact on outcome of distal hypospadias repair is still a matter of controversy; the current study tried to minimize both duration of stenting for a mean of 3.9 days. However, Samuel et al. (7) reported that stenting or urinary diversion is unnecessary after distal hypospadias surgery and the functional results were good in those standing to void. O'Sullivan et al. (17), (2006), concluded that stenting can be abandoned in distal hypospadias repairs without compromising patients outcomes. On the contrary, El-Sherbiny (18), (2003), reported that the use of a stent in TIP repair in toilet-trained children is advantageous; it significantly eliminates the risk of urinary retention and extravasation, reduces the overall patient discomfort and is also associated with a lower re-operation rate. Akbiyik et al. (19), (2009), maintained long duration of urethral stenting as patients were hospitalized for 10 days postoperatively, with a urethral stent in place, but they reported that the most frequent complication was meatal stenosis, followed by urethrocutaneous fistula. the reported high frequency of meatal stenosis is their most common complication and could be attributed to such long duration of stenting Conclusion Despite both procedures were technically feasible, Snodgrass procedure with spongeoplasty was advantageous with significantly higher success rate and better cosmetic results inducing significantly higher parents' satisfaction rate. Moreover, Snodgrass procedure with dartos fascia coverage for redo cases showed high success rate. REFERENCES 1. Mamed-zade GT: Congenital development disorder: the system of data collection. Georgian Med News, 2009; (166): Frank JD, Mouriquand P, Caldamone A: The incidence of hypospadias is increasing. J Pediatr Urol. 2010;6(1):1. 3. Bragg TW, Ali SN, Warner R, Park AJ: Hypospadias surgery in plastic surgery: a snapshot of today with an eye on tomorrow. J Plast Reconstr Aesthet Surg. 2009; 62(3): Duckett JW. Transverse preputial island flap techniques for repair of severe hypospadias. Urol Clin North Am 1980; 7: Elder JS, Duckett JW, Snyder HM. Onlay island flap in the repair of mid and distal penile hypospadias without chordee. J Urol., 1987; 138: Snodgrass W. Tubularized, incised plate urethroplasty for distal hypospadias. J Urol 1994; 151: Samuel M, Capps S, Worthy A: Distal hypospadias: which repair? BJU Int. 2002; 90(1): Al-Saied G, Gamal A: Versatility of tubularized incised plate urethroplasty in the management of different types of hypospadias: 5-year experience. Afr J Paediatr Surg., 2009; 6(2): Mouriquand PDE, Mure PY: "Hypospadias" in: Gearhardt JP, Rink RC, Mouriquand PDE (eds) Pediatric urology. Saunders, Philadelphia, 2001; Pp Moradi M, Moradi A, Ghaderpanah F: Comparison of snodgrass and mathieu surgical techniques in anterior distal shaft hypospadias repair. Urol J. 2005; 2(1): Sarhan OM, El-Hefnawy AS, Hafez AT, Elsherbiny MT, Dawaba ME, Ghali AM: Factors affecting outcome of tubularized incised plate (TIP) urethroplasty: singlecenter experience with 500 cases. J Pediatr Urol. 2009; 5(5): Abolyosr A: Snodgrass hypospadias repair with onlay overlapping double-layered dorsal dartos flap without urethrocutaneous fistula: Experience of 156 cases. J Pediatr Urol Oct 24; Epub ahead of print.

9 Kasr El Aini Journal of Surgery VOL., 11, NO 1 January Mahmoud MT, Ahmed J, Athar MS, Ashraf MS: Modification of Mathieu procedure to repair anterior hypospadias. J Coll Physicians Surg Pak. 2006; 16(4): Ghanem MA, Nijman RJ: Outcome analysis of tubularized incised urethral plate using dorsal dartos flap for proximal penile hypospadias repair. J Pediatr Urol Jan 26, Epub ahead of print. 15. Shehata SM: Use of the TIP principle for the repair of non-glanular recurrent post hypospadias urethrocutaneous mega fistula. Eur J Pediatr Surg.;19(6): Ozturk H: Dartos flap coverage of the neourethra following repair for primary hypospadias, reoperative hypospadias and urethrocutaneous fistulas. It is a safe approach. Acta Cir Bras. 2010; 25(2): O'Sullivan O, Bannon CA, Flood H: The Snodgrass repair: is stenting always necessary? Ir Med J. 2006;99(3): El-Sherbiny MT: Tubularized incised plate repair of distal hypospadias in toilet-trained children: should a stent be left? BJU Int. 2003; 92(9): Akbiyik F, Tiryaki T, Senel E, Mambet E, Livanelioglu Z, Atayurt H: Clinical experience in hypospadias: results of tubularized incised plate in 496 patients. Urology. 2009;73(6):

10 Kasr El Aini Journal of Surgery VOL., 11, NO 1 January