Hypospadias
Key points
Pathophysiology
Failure of urogenital folds to fuse
Hypoplasia beyond division of corpus spongiosum
Genetics/Heredity
10% incidence in 1st degree relatives
Isolated hypospadias - 70% of all cases
Monogenic or chromosomal causes - 30% of cases
Sibling risk- 15%
7% of fathers of a child with hypospadias are also affected
Associations
WAGR
Denys Drash
Investigations
Karyotype if unilateral or bilateral undescended testis (UDT)
Up to 50% if hypospadias + UDT may have Differences of Sex Differentiation (DSD)
Standard scenario
Concerns:
1. Functional (PU standing, straight erections) and cosmetic
2. Is it a DSD or part of a syndrome?
History:
Any antenatal issues
Voiding patterns
UTIs
Family history
Examination:
Meatus + size of glans
Chordee + size of shaft
Foreskin
Testes
Dysmorphic features - e.g.
McKusick-Kaufman (MKS) genetic condition (glanular hypospadias & undescended testes PLUS polydactyly & cardiac)
Investigations:
FISH + Karyotype if concerns
Referral to endocrine + MDT if DSD suspected
Management:
Age 1 - pre op clinic to re-examine and take consent, explain dressings etc
Procedure: EUA + single/staged hypospadias repair +/- artificial erection test/correction of chordee +/- foreskin reconstruction/modified circumcision
Single stage tubularised incised plate urethroplasty (TIP, Snodgrass) with dartos waterproofing layers (Byers flap)
OR if not possible 1st stage - degloving + correction of chordee and ventral resurfacing with free preputial graft (excise existing urethral plate)
If perineal - will need long graft
If severe chordee - Nesbits procedure - removal of ellipse of corpora opposite maxiumum curvature then suturing to straighten - preserving dorsal neurovascular bundle
Note that an apparent distal meatus could still have a short urethra needing staged repair
2nd stage in 6 months - tubularisation
If small penile length:
Testosterone injections by endocrine monthly for 3 months, last injection 1 month before procedure
Can give topical cream for 4-6 weeks
Check dorsal stretched penile length against nomogram
Buccal graft if no foreskin available (for redo for example)
Can also use post auricular skin
Follow up:
Flow rate at first clinic in 6 months
Further follow ups according to result (can be patient initiated follow up if well)
References
Essentials of Pediatric Urology, 3rd edition, 2022, Chapter 16 Hypospadias