|Year : 2019 | Volume
| Issue : 2 | Page : 51-56
Results of urethral plate preservation and use of vascular dartos flap in hypospadias repair
Rajendran Ramaswamy, Samir Morsy Hegab, Rayan Ahmed Baz, Saif Saeed Galib, Ghazi Mukattash
Department of Pediatric Surgery, Maternity and Children's Hospital (Under Ministry of Health), Najran, Saudi Arabia
|Date of Web Publication||6-Sep-2019|
Department of Pediatric Surgery, PB. No. 3600, Maternity and Children's Hospital (Under Ministry of Health), Najran
Source of Support: None, Conflict of Interest: None
Background: Lower complication rates are observed if urethral plate (UP) is preserved and utilized for reparative surgery of hypospadias.
Aim: This study aims to analyze our results of hypospadias repair by UP preservation, and using vascular dartos flap as interposition flap.
Materials and Methods: prospective, cohort study of operated cases of hypospadias over 4.5 years' period. Data including age, diagnosis, preoperative testosterone administration, operation, postoperative complications, and assessment of outcome using hypospadias objective scoring evaluation (HOSE) system were collected. We preserved UP as far as possible, for urethral tube construction. We applied meatal advancement and glanuloplasty incorporated (MAGPI) for glanular/coronal hypospadias and tubularized incised plate urethroplasty (TIPU) (Snodgrass) for most other cases. Single dorsal vascular dartos-flap was transposed ventrally as interposition flap in TIPU. Single transurethral catheter 6F/8F size was employed as urethral stent as well as for bladder drainage. At the first review at 2 weeks after getting discharged, all patients underwent urethral calibration and first HOSE-score assessment. Maximum HOSE-score was 16 points and minimum 5.
Results: A total of 111 patients with mean (range) age of 34.69 m (11 m– 123 m) were studied. TIPU (n = 49), MAGPI (n = 44), and others (n = 18) were the operations. There were 10 permanent complications; 9 following TIPU (7 (14.3%) single urethrocutaneous fistula (UCF), 1 torsion penis, 1 glans-dehiscence), and 1 following MAGPI (glans-dehiscence). Mean follow-up period was 15 m (range = 3–36 m). HOSE score ≥14 was achieved in 106 (95.5%) cases.
Conclusion: The excellent result of MAGPI in our series is due to strict case selection and technical precision. UCF rate of 14.3% in TIPU can be due to the unselected nature of our cases which included small glans diameter and unfavorable UP characteristics.
Keywords: Dorsal vascular dartos flap, hypospadias objective scoring evaluation score, meatal advancement and glanuloplasty incorporated, tubularized incised plate urethroplasty (Snodgrass), urethral plate preservation
|How to cite this article:|
Ramaswamy R, Hegab SM, Baz RA, Galib SS, Mukattash G. Results of urethral plate preservation and use of vascular dartos flap in hypospadias repair. Saudi Surg J 2019;7:51-6
|How to cite this URL:|
Ramaswamy R, Hegab SM, Baz RA, Galib SS, Mukattash G. Results of urethral plate preservation and use of vascular dartos flap in hypospadias repair. Saudi Surg J [serial online] 2019 [cited 2022 Aug 16];7:51-6. Available from: https://www.saudisurgj.org/text.asp?2019/7/2/51/266208
| Introduction|| |
In hypospadias repair, if urethral plate (UP) is preserved and incorporated, lower complication rates are observed. The cause of chordee in most cases of hypospadias is skin chordee or fibrous dartos fascia. True fibrous chordee due to deficiency or fibrous replacement of normally elastic UP is rare and rarer is corpora cavernosa disproportion. Thus UP preservation is possible in most cases. Meatal advancement and glanuloplasty incorporated (MAGPI), glans approximation procedure (GAP), tubularized incised plate urethroplasty (TIPU), Mathiew's flip-flap urethroplasty, and onlay-patch urethroplasty are the common UP preserving methods of hypospadias repair. Patients with midshaft and more distal hypospadias can undergo TIP repair. However, many cases of mid and proximal penile hypospadias have a well-developed UP and exhibit little or no chordee after release of skin tethering. Patients with this combination of findings are ideal candidates for TIPU or onlay island flap urethroplasty regardless of initial meatal position. Dorsal subcutaneous flap from the prepuce was first used as interposition flap in urethral tube construction by Retik in 1988.
UP preservation and its tubularization or augmentation plus tubularization are preferred in the repair of hypospadias. We analyzed our results of hypospadias repair by UP preserving methods and using vascular dartos flap as interposition flap.
| Materials and Methods|| |
This was prospective, cohort study of operated cases of hypospadias in our department over a period of 4.5 years (June 2013–December 2017). Ours is a tertiary care referral teaching hospital. Institutional approval for the study was obtained. Almost all cases were operated by the first author as the main surgeon. Data collected include age at operation, preoperative diagnosis, presence of chordee, additional penile anomaly, preoperative administration of testosterone, special procedure for chordee correction, type of hypospadias after chordee correction, method of urethroplasty, postoperative complications, follow-up period, and assessment of outcome. In cases of hypoplastic penis for age, we tried to get consent from the father of the child to preoperative testosterone injection. Testosterone propionate at 2 mg/kg/dose intramuscular injection 3 doses at intervals of 3 weeks was given. The last such injection was given 3 weeks before the operation. During hypospadias correction, it was our policy to preserve the UP as far as possible, for urethral tube construction. It was routine to ensure complete chordee correction intraoperatively using the artificial erection test (Gittes-Mclaughlin). After penile degloving with release of fibrous Dartos/Bucks fascia, if chordee of <30° persisted, bilateral dorsal corporal plication (modified Nesbit) was done. If chordee more than 30° persisted, then the UP was excised and chordee correction completed. Either pedicled tube urethroplasty or ventral transfer of dorsal prepuce as the first stage of staged urethroplasty (Bracka) was followed. Those patients in whom the UP was sacrificed are excluded from this study. MAGPI was generally used for glanular and coronal hypospadias correction [Figure 1]. As far as possible, we employed the TIPU (Snodgrass) in all other cases. In TIPU, midline incision of UP (MIUP) extended from proximal to hypospadiac external urethral meatus to the tip of glans. Single dorsal vascular dartos-flap was transposed ventrally along one side of shaft (in earlier cases of the series) or after button-holing the center and threading the glans penis through it, to superimpose the urethral tube as interposition flap in TIPU [Figure 2]. Penile shaft was covered by ventral transposition of dorsal prepuce as Byars flaps and redundant skin was excised. Complete removal of prepuce was preferred by people of this country. Occasionally only, other operations for hypospadias repair (GAP, onlay-patch urethroplasty [Figure 3], and Thiersch-Duplay) were done. Single Nelaton's catheter (B. Brawn, Germany) 6F/8F size was employed as urethral stent as well as for bladder drainage. Patients were given low dose of diazepam (0.2 mg/kg/12 h) to prevent penile erection which can aggravate pain. The stent was removed after 48 h in cases of MAGPI, and retained for 5–14 days in other types of repair. Patients were discharged home after ensuring that he passed urine after catheter removal. At the first review at 2 weeks after getting discharged, all patients underwent urethral calibration using 6F/8F infant feeding tube, in the outpatient clinic. This ensures that neourethra has adequate caliber, and identifies urethral stricture/meatal stenosis/urethrocutaneous fistula (UCF) if any. Children with urethral stricture/meatal stenosis underwent urethral dilation in subsequent visits as outpatient procedure. The result of urethroplasty was assessed using hypospadias objective scoring evaluation (HOSE) in the follow-up. HOSE takes into consideration the external urethral meatus location, meatus shape (vertical/circular), the urinary stream (single/spraying), the state of penis during erection (straight/curved), and UCF (number/location) if any. Maximum HOSE-score is 16 points and minimum score is 5.
|Figure 1: Meatal advancement and glanuloplasty incorporated for coronal hypospadias. (a) Coronal hypospadias. (b) Glans-wings approximation in meatal advancement and glanuloplasty incorporated. (c) Postoperative appearance of glans after meatal advancement and glanuloplasty incorporated showing apical vertically slit-like meatus|
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|Figure 2: Tubularized incised plate urethroplasty (Snodgrass) for midpenile hypospadias. (a) Midpenile hypospadias, with fairly wide and cleft urethral plate, is ready for tubularized incised plate urethroplasty. (b) After neourethral tube construction in tubularized incised plate urethroplasty. (c) Vascular dartos flap from dorsal prepucial skin button-holed in its center before ventral transfer. (d) Vascular dartos-flap interposed and glans-plasty completed. (e) Covering of penile shaft is completed. (f) Postoperative appearance after tubularized incised plate urethroplasty|
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|Figure 3: Midpenile hypospadias with narrow urethral plate ready for augmentation with transverse prepucial island patch|
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| Results|| |
A total of 111 patients were included in the study. Their mean (range) age was 34.69 m (11–123 m), with 56% of them aged ≤24 m. Types of hypospadias were glanular (n = 20), coronal (n = 36), subcoronal (n = 23), distal penile (n = 21), midpenile (n = 7), and megameatus intact prepuce (MIP) variant (n = 4). Chordee was found in 77 (69.36%) cases. The additional penile torsion was present in 14 cases and penoscrotal web in two cases. Two cases were precircumcised. One case of distal penile hypospadias was twice failed repair in another hospital. Three patients were given preoperative testosterone. Chordee correction by modified Nesbit corporoplasty was needed in 18 (23.37%) cases. The different methods of urethroplasty done for different types of hypospadias are given in [Table 1]. TIPU (Snodgrass) was the most common repair (n = 49), followed by MAGPI (n = 44). One case of glanular hypospadias with urine-deflecting dorsal glanular flap was corrected by dorsal meatotomy only. Five cases of glanular hypospadias with chordee needed only chordee correction, by which the meatus moved forward to more acceptable position. Complications of operation are shown in [Table 2]. In the immediate postoperative period, temporary complications occurred in 10 cases; all such complications disappeared later. Out of 10 permanent complications, 9 followed TIPU; 7 single UCF, 1 anticlockwise torsion of 40°, and 1 glans-dehiscence. The only one glans-dehiscence following MAGPI occurred in the beginning of this series. No complication occurred in other types of hypospadias repair. Mean follow-up period was 15 m (range = 3 m–36 m). In the postoperative HOSE assessment, meatus was at distal glanular location in 102, its shape was vertical slit-like in 93, urinary stream was single in 96, straight penis in erection was found/reported by parents in all, and single UCF was found in seven cases. In MAGPI cases, all but 1 resulted in apical and slit-like meatus. HOSE score ≥14 was achieved in 106 (95.5%) cases.
| Discussion|| |
Histopathological studies of UP in newborn penis and fetal penis with hypospadias proved that there were extensive blood vessels, glands, collagen, and smooth muscle under the UP in hypospadias specimens. UP has rich nerve supply also. These tissues corresponded to abnormally formed corpus spongiosum. These features may explain the lower complication rate if UP is preserved and used for hypospadias repair. In 1981, Ducket proposed MAGPI for correction of anterior hypospadias. It preserves UP and is a plastic surgical rearrangement of external urethral meatus and glans wings. The two UP-preserving operations we employed in the vast majority of hypospadias repair were TIPU-Snodgras (44.14%) and MAGPI (40%). We preferred MAGPI to TIPU for coronal and glanular hypospadias repair. This is based on two reasons. MAGPI involves advancement (reflection) of the ventral skin-cuff distally to form ventral urethra, and does not have suture-line in the ventral urethra unlike TIPU. There is no need of interposition layer on this ventral urethra. MAGPI is associated with minimal complications, short hospital stay, improved cosmetic appearance of glanular hypospadias and coronal hypospadias, and resultant patient and parental satisfaction. Duckett originally employed MAGPI to correct anterior hypospadias (glanular, coronal, and distal penile) in which no fibrous chordee was demonstrated by artificial erection test. However, MAGPI is feasible after correction of skin-chordee, and after correction of chordee from fibrous Dartos/fibrous Buck's fascia. In our experience, even in other cases of persistent chordee <30°, after dorsal corporal plication, MAGPI is successful. Unluer found MAGPI give excellent cosmetic and functional results in 94% of their cases in the early postoperative period; long-term results in 41 boys between 6 and 40 (mean 29) months' postoperatively showed partial meatal regression in 22% of cases and complete regression in 15%. On the long-term, excellent cosmetic results were achieved in all glanular cases but in only 65% of coronal and 15% of subcoronal cases. Hence, he recommended that the MAGPI procedure is not a suitable operation for subcoronal hypospadias. Duckett reviewed his 266 cases from 1987 to 1990. Complications included 5 fistulas (0.45%), 7 meatal retractions (0.6%), 1 residual chordee (0.09%), and no meatal stenosis. The incidence of complications requiring secondary surgery in his total 1111 cases was 1.2%. Meatal stenosis can be avoided by Heineke-Mikulicz tissue rearrangement of dorsal urethral wall after making an MIUP from within the urethral meatus well distally into the urethral groove. The nature of the meatus and the parameatal skin is of paramount importance in achieving a successful glans reconfiguration following MAGPI. The parameatal skin should be thick and pliable, permitting it to be lifted easily off the underlying urethra, to be advanced distally. The glans configuration must permit it to wrap around this advanced ventral urethral wall. If the parameatal skin is thin or nonpliable, then an onlay island flap often is more appropriate. A meatus too wide or too proximal should be avoided for MAGPI. The glansplasty consists of glans-wings approximation in two layers to support the advanced ventral urethral wall. This step prevents retrusive meatus. Before glansplasty, skin adjacent to the glanular edges must be excised. Contraindications to MAGPI repair are presence of thin nonmobile skin ventral to meatus, MIP variant of distal hypospadias and wide, and deep urethral groove with subcoronal meatus. Livne and McMillan also published excellent results with MAGPI. We used MAGPI to repair glanular and coronal varieties only. The only one complication (2.27%) of glans dehiscence was in an earlier case in this series. The excellent result of MAGPI in our series is attributed to strict selection of cases and adherence to perfect technique. In a recent report by Kocaman, coronal hypospadias patients were repaired by MAGPI (29.1%) and TIPU (70.9%) techniques. In MAGPI, glans wings were apposed with sutures taking bites from the urethra to avoid meatal regression. MAGPI group had only 1 (3.6%) complication (meatal stenosis), whereas TIPU group had 9 (13.26%) complications including 3 (4.4%) reoperations.
We do not practise Mathieu repair because tubularized incised urethroplasty (TIP)-repair creates more normal appearing glans and meatus compared to Mathieu even though both give similar uroflowmetry results and similar complication rates (6.9%). TIPU was used mainly for midpenile and distal penile hypospadias except coronal hypospadias. In TIPU, there is ventral urethral suture-line, and there is intermediate superimposition layer to prevent urethral fistula. Vascular dartos-flap coverage of TIP repair offers a significant reduction in fistula rate after TIPU in distal hypospadias, but single or double layers of dartos coverage had no significant difference in results. In 2010, Snodgrass published his results of 551 consecutive patients with distal hypospadias undergone UP tubularization with (459) or without (92) midline incision. Complications developed in 19 (4%), including nine fistulas, nine glans dehiscences, and one delayed meatal stenosis from balanitis xerotica obliterans. He observed no contraindication to this procedure for distal hypospadias. He confirmed the low complication rate and high success using varied suture materials and methods.
In 2009, Snodgrass advocated an expanded algorithm for penile straightening in proximal hypospadias surgery to preserve the UP for urethroplasty. It involved mobilization of the corpus spongiosum/UP and proximal urethra to correct chordee before UP transection. The rate of UP transection significantly decreased from 54% to 15% using this expanded algorithm. However, on follow-up of such cases, the complication of symptomatic urethral strictures developed in 17% of such cases. Snodgrass no longer recommend UP elevation and urethral mobilization with proximal TIPU. In proximal hypospadias repair, some authors have found that UP preservation is possible if chordee is lower than 45° and in ¾ of cases where curvature is 45°–90°.
When the urine flow-rates following primary distal TIPU, proximal TIPU, and two-stage grafts were compared, it was found that Qmax and Qave were the same. A third of patients more than 14 years of age who had hypospadias repair using skin flaps, at <6 years of age, reported obstructive voiding symptoms, spraying, or deviated streams. About 25% of patients also report having to milk their ejaculate from the neourethra. These findings indicate that their neourethra is not a normal urethra. Today, tubularization of the UP, usually after dorsal incision to widen it, is the most common means used to correct distal hypospadias and is also an option to repair proximal cases that have either no curvature or bending of <30°. In postoperative assessment, a total HOSE score of 14 has been recommended as an acceptable outcome in the present era of hypospadias repair., Al-Adl et al. objectively assessed the functional and cosmetic outcomes in 43 patients undergoing TIPU with the distal extension of the MIUP without grafting and achieved a HOSE score of ≥14 in 98% of the patients.
Glans size is an independent predictor for urethroplasty complications (UCs). Glans diameter, measured at the widest point if ≤14 mm, there is a 2.7-fold greater risk for UCs, and each millimeter increase reduces that risk. Most patients with small glans have proximal hypospadias, but some have distal hypospadias. Urethral groove depth appears to influence neourethral caliber after TIPU. In a series of 46 patients with distal hypospadias who underwent TIP-repair, of the boys with a shallow urethral groove, 6 (40%) had a neourethral caliber of 6Fr or less versus 3 (15%) with a moderate and 0 with a deep groove. Each patient in whom meatal stenosis developed had a shallow urethral groove. Urethral fistula developed in 6 (13%) patients with UP width <8 mm only. Urethral fistula rate of 2.4% and failed 8F urethral calibrations were observed in 5.95% cases where UP width was >8 mm, whereas fistula rate of 23% and failed 8F calibrations in 26.9% were observed in cases where plate width was <8 mm. Cases with flat UP had 15.4% fistula rate and 26.9% failed 8F urethral calibrations in a study by Aboutaleb. The incidence of 7 UCF (14.3%) and 1 glans dehiscence in the TIPU group of our series may be due to unselected nature of our cases which included small glans and unfavorable UPs. Preoperative testosterone therapy has been found effective in increasing penile length and circumference, fewer postoperative complications, and improved cosmesis. Only three cases in our whole series accepted preoperative testosterone injection. Complication of anticlockwise torsion of penis due to swinging of superimposition dartos-flap through the left side of penile-shaft could be avoided in the later cases by button-holing the center of dartos-flap and bringing to ventrum. Grafting the dorsal TIP incision (G-TIP) is considered an option to fill the defect and ensure healing without stenosis., The onlay island flap urethroplasty, a variant of the transverse preputial (tubularized) island-flap, was originally described for repair of anterior hypospadias. In 1990, Howell reported that onlay island-flap has been used for repair of mid to posterior hypospadias in 31 patients (38% of the cases), resulted in significantly lower complication rate (10%) compared to other standard techniques. Slightly different from the transverse prepucial island patch urethroplasty which we did, Chandrasekharam did onlay longitudinal dorsal island flap (LDIF) repair in 85 children. Complications rate was 9.5%. His results indicate that the specific advantages and versatility of LDIF make it a good option to consider in cases of hypospadias with poorly developed UPs where onlay or substitution urethroplasty is indicated.
| Conclusion|| |
UP should be preserved and utilized for neourethral tube construction in hypospadias repair as far as possible. Excellent result of MAGPI in our series is due to strict case selection and technical precision. The high rate of UCF in the present series of TIPU can be due to small glans diameter and unfavorable UP characteristics. In the presence of such unfavorable factors, preoperative testosterone injection, and one of the UP augmentation methods of urethroplasty such as onlay patch urethroplasty or G-TIPU should be adopted.
The authors gratefully acknowledge the motivation and co-operation extended by the then medical director of maternity and children's hospital, Najran, Saudi Arabia, Dr. Mamdough AlOthmany Mohamed, in using the hospital data and bringing out this research paper.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]