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Hypospadias: Classification and Repair
Definition and Epidemiology
Hypospadias is a congenital anomaly characterized by the urethral meatus being located on the ventral surface of the penis, proximal to its normal position at the glans. It occurs in approximately 1 in every 200 to 300 live male births, making it one of the most common congenital anomalies. The condition is defined by a triad of abnormalities: an ectopic ventral urethral meatus, ventral curvature of the penis known as chordee, and a dorsal hooded foreskin due to ventral foreskin deficiency. There is a familial tendency, with an 8% risk if the father is affected and a 14% risk if a sibling has hypospadias.
Embryology
During normal development, the urethral folds fuse in the midline from proximal to distal between the eighth and sixteenth weeks of gestation. Hypospadias results from incomplete fusion of these urethral folds. Its etiology is multifactorial, involving genetic susceptibility combined with hormonal and environmental influences. Testosterone and its more potent derivative dihydrotestosterone (DHT), produced by 5-alpha reductase, are critical for proper urethral development. Exposure to endocrine disruptors has been implicated, though this remains controversial.
Classification
By Meatal Location
Hypospadias is classified based on the location of the urethral meatus. The most common type is glanular or subcoronal, where the meatus is located on the glans or corona, accounting for about 50% of cases. Distal penile hypospadias, involving the distal shaft, comprises roughly 20%, while midshaft and proximal penile types each represent about 10%. Less common are penoscrotal (5%), scrotal (3%), and perineal (2%) locations. Overall, distal hypospadias (glanular, subcoronal, distal penile) make up approximately 70% of cases, whereas proximal forms (proximal penile, penoscrotal, scrotal, perineal) constitute about 30%.
| Meatal Location | Frequency | Category |
|---|---|---|
| Glanular / Subcoronal | ~50% | Distal |
| Distal penile | ~20% | Distal |
| Midshaft | ~10% | — |
| Proximal penile | ~10% | Proximal |
| Penoscrotal | ~5% | Proximal |
| Scrotal | ~3% | Proximal |
| Perineal | ~2% | Proximal |
Chordee Assessment
Ventral curvature, or chordee, is assessed intraoperatively using an artificial erection test. Curvature is classified as mild if less than 30 degrees, moderate between 30 and 45 degrees, and severe if greater than 45 degrees. The cause of chordee varies: in distal hypospadias, it is most commonly due to skin tethering. Fibrous tissue within the dartos or Buck's fascia can also cause curvature, while true chordee results from corporal disproportion, where the dorsal aspect of the corpora cavernosa is shorter than the ventral side.
<image>Classification diagram of hypospadias showing meatal locations from glanular to perineal with corresponding anatomic illustrations of the penile shaft and ventral curvature</image>
Associated Anomalies
Hypospadias is frequently associated with other anomalies. Undescended testis occurs in about 9% of cases overall, with a higher incidence in proximal hypospadias. Inguinal hernias are also seen in approximately 9%. Disorders of sex development (DSD) should be considered in patients presenting with proximal hypospadias combined with bilateral or unilateral undescended testes, or any hypospadias accompanied by ambiguous genitalia. The workup for DSD includes karyotyping, measurement of 17-hydroxyprogesterone, testosterone, dihydrotestosterone levels, and pelvic ultrasound. Upper urinary tract anomalies are rare, occurring in less than 5% of cases, and routine renal ultrasound is not recommended for isolated distal hypospadias.
Preoperative Considerations
Timing of Surgery
The American Urological Association recommends performing hypospadias repair between six and twelve months of age. This timing balances adequate penile size for surgery, minimal psychological impact, and completion before toilet training begins. In cases of micropenis or a small glans, testosterone stimulation may be employed preoperatively to increase penile size. This can be achieved by applying topical dihydrotestosterone or testosterone cream to the penis for four to six weeks or by administering intramuscular testosterone at 25 mg monthly for one to three doses. However, the use of testosterone is controversial because it may increase vascularity and tissue edema, potentially complicating surgery.
Preoperative Assessment
A thorough preoperative evaluation includes assessing the meatal location, glans size and configuration, degree of chordee, penile size, and scrotal anatomy. The presence of undescended testes or features suggestive of DSD must be noted. Importantly, circumcision should be avoided because the foreskin provides essential tissue for surgical repair. If hypospadias is identified at birth and parents request circumcision, counseling should emphasize preserving the foreskin.
Surgical Techniques
Distal Hypospadias Repairs
TIP (Tubularized Incised Plate) - Snodgrass Procedure
The TIP repair, also known as the Snodgrass procedure, is the most widely used technique globally for distal and some mid-shaft hypospadias. The procedure involves making a U-shaped incision around the meatus and raising the urethral plate. A midline relaxing incision is then made dorsally through the urethral plate to allow tubularization over a catheter using absorbable running sutures. A dartos flap harvested from the dorsal prepuce is used as a waterproofing layer. The glans wings are approximated during glansplasty, and a meatoplasty is performed to create a natural-appearing meatus. This technique is versatile, yields a cosmetically pleasing result, and has a high success rate of 90-95% for distal and 80-90% for mid-shaft repairs. Complications include urethrocutaneous fistula formation in 3-5% and meatal stenosis in 5-10%.
Mathieu (Meatal Advancement and Glanuloplasty - MAGPI variant)
The Mathieu repair uses a perimeatal-based flap that is advanced distally and tubularized. It is suitable for subcoronal hypospadias with adequate ventral skin. The success rate ranges from 85-90%, but the resulting meatus tends to be slit-like, which may be a cosmetic concern.
MAGPI (Meatal Advancement and Glanuloplasty)
This technique is reserved for glanular hypospadias with a thin glanular web. It involves a dorsal meatotomy combined with ventral advancement of the meatus. MAGPI is a simple outpatient procedure but is limited to the most distal defects.
GAP (Glans Approximation Procedure)
The GAP is used when there is a wide, deep glanular groove. It involves tubularizing the existing groove without incising the urethral plate. When the anatomy is favorable, this method has a high success rate.
Proximal Hypospadias Repairs
Two-Stage Repair (Bracka/Byars)
For proximal hypospadias with severe chordee, failed prior repairs, or an inadequate urethral plate, a two-stage repair is often employed. The first stage involves straightening the penis by correcting chordee and placing a graft—usually buccal mucosa or inner prepuce—on the ventral surface. After a maturation period of about six months, the second stage tubularizes the graft to form a neourethra. This approach has a success rate of 75-85% overall but carries a higher complication rate compared to distal repairs.
Onlay Island Flap (OIF)
The Onlay Island Flap technique uses an inner preputial island flap laid on the urethral plate as an onlay without transecting the plate. It is suitable for mid-to-proximal hypospadias when the urethral plate is adequate.
Tubularized Preputial Island Flap (Duckett)
The Duckett repair involves tubularizing an inner preputial flap into a tube and transferring it ventrally. It is used for proximal hypospadias when the urethral plate is unusable. This technique has a higher complication rate, including fistula and diverticulum formation, and has largely been replaced by two-stage repairs or extended TIP procedures.
<image>Step-by-step surgical illustrations of the TIP (Snodgrass) procedure showing U-incision, urethral plate incision, tubularization, dartos flap coverage, and glansplasty</image>
Chordee Correction
Chordee is assessed intraoperatively using an artificial erection test, which involves saline injection into the corpora cavernosa. Mild chordee can often be corrected by skin degloving, which releases skin and dartos tethering. If curvature persists, excision of ventral fibrous tissue is performed. For residual curvature greater than 20 to 30 degrees after tissue release, dorsal plication techniques such as the Baskin or Nesbit procedures are used to shorten the dorsal side and match the ventral length. In cases of severe corporal disproportion with curvature exceeding 45 degrees, ventral corporotomy with grafting (using dermal, tunica vaginalis, or small intestinal submucosa grafts) is reserved.
Complications
Early
The most common early complication is urethrocutaneous fistula, occurring in 5-10% of cases. Repair should be delayed for at least six months to allow tissue maturation. Small fistulas can be managed with simple layered closure, while larger or recurrent fistulas often require interposition of tissue such as dartos or tunica vaginalis flaps. Meatal stenosis occurs in 5-10% and is managed with meatotomy or serial dilation. Wound infection and dehiscence are uncommon with proper surgical technique, and hematoma or bleeding may occur.
Late
Late complications include urethral diverticulum, which is ballooning of the neourethra during voiding due to redundant tissue in the repair; this may necessitate excision and redo tubularization. Urethral stricture occurs in 1-5% and can be managed with dilation, direct vision internal urethrotomy, or open revision. Recurrent chordee may require reoperation, and residual curvature might not become apparent until puberty or during erection. Cosmetic dissatisfaction can arise from meatal position, penile torsion, or overall appearance. Lichen sclerosus (BXO) is a late complication that can affect skin grafts or the neourethra.
Redo Hypospadias (Cripple Hypospadias)
Failed prior repairs present a challenging reconstructive scenario. The most reliable approach for complex redo cases is a two-stage buccal mucosa graft repair. Local tissue flaps may be used if available, and a tunica vaginalis flap is often employed as a waterproofing layer. These cases should be referred to experienced hypospadiologists, as multiple prior repairs significantly increase complication rates.
<image>Intraoperative photographs showing a completed TIP repair at 6 months postoperatively with well-positioned meatus, and an example of a urethrocutaneous fistula complication</image>
Postoperative Care
Postoperatively, a catheter or stent is typically left in place for 5 to 10 days, either as a urethral catheter or suprapubic diversion. A pressure dressing using Tegaderm or Coban wrap is applied for 24 to 48 hours. Prophylactic antibiotics are administered during the catheterization period. Activity restriction is advised for 4 to 6 weeks, avoiding straddle activities. Anticholinergic medications such as oxybutynin may be given to reduce bladder spasms in catheterized children. Follow-up visits are scheduled at 1 to 2 weeks postoperatively, then at 3, 6, and 12 months. Long-term follow-up through puberty is recommended to monitor for late complications.
Clinical Pearls
It is imperative never to circumcise a child with hypospadias because the foreskin provides the primary tissue source for surgical repair. The TIP (Snodgrass) procedure is the most versatile and widely used technique for distal hypospadias, consistently achieving high success rates of 90-95%. Chordee must be assessed intraoperatively using an artificial erection test, as clinical assessment alone is unreliable. Urethrocutaneous fistula is the most common complication, and repair should be delayed for at least six months to allow tissue maturation. For proximal hypospadias with severe chordee, a two-stage approach using buccal mucosa grafts remains the most reliable strategy. In cases of proximal hypospadias with bilateral undescended testes, a thorough DSD workup including karyotype and hormone studies is mandatory before any surgical intervention. Testosterone stimulation before surgery can be useful for patients with small glans or micropenis, although its routine use is still debated.
References
- AUA Guideline on Hypospadias (in development)
- EAU/ESPU Guidelines on Pediatric Urology (Hypospadias), 2024 Update
- Snodgrass WT. "Tubularized incised plate urethroplasty for distal hypospadias." J Urol. 1994;151(2):464-465.
- Snodgrass WT, Bush NC. "Primary hypospadias repair techniques." Urol Clin North Am. 2016;43(3):285-293.
- Springer A, et al. "Hypospadias: a comprehensive review." Eur Urol. 2016;69(3):426-435.
- Campbell-Walsh-Wein Urology, 12th Edition, Chapter on Hypospadias
