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Hypospadias

by Kieran Jefferson

Definition and classification
Embryology
Surgery
Epispadias
Micropenis

Definition:

Assocation of

1. Abnormal ventral meatal opening

2. Ventral penile curvature (chordee)

3. 'Hooded' prepuce

Classification:

Brown (1936)

Barcat (1973) - post-orthoplasty position

The location of the meatus after correction of curvature provides the most practical classification of hypospadias. The glanular and coronal types constitute anterior hypospadias, which accounts for 50% of all cases. The distal penile midshaft and proximal penile types account for 30% of cases. Penoscrotal, scrotal and perineal types make up the 20% that are classified as posterior (from Duckett, JW (1992) Successful hypospadias repair. Contemporary Urology 4, 42-55).

Embryology

Formation of the genital tubercle and lateral genital folds (indifferent) occurs during 6/40. DHT dependent elongation of the phallus and urethral groove forms between lateral folds (during 10/40), and the epithelial lining of the groove forms the urethral plate. The folds then coalesce in the midline (during 12/40), forming the urethra proximal to the glans. The glanular urethra results from canalisation of the solid cord of epithelial cells.

Hypospadias results when fusion is incomplete. However, pathogenesis of the chordee is disputed, it may be due to fibrous tethering or differential growth.

Aims of treatment	To produce a forward stream, a straight erect penis and good cosmesis.
Genetics	8% with fathers showing condition, 14% with male sibs also showing condition. More common in whites, especially Jews and Italians.
Aetiology	There may be a deficiency of androgens during embryogenesis. It is more common in twins.
Associations	Undescended testis (9%), inguinal hernia (9%), prostatic utricle (10%) and small incidence of upper UT anomolies.
Incidence	1:300 live male births (doubled since 1970)

Hypospadias Surgery

Optimal age is 6-18 months. There are five steps:

Orthoplasty (correction of chordee)
Urethroplasty
Meatoplasty and glanuloplasty
Skin cover
Scrotoplasty - rarely needed

Other considerations are one-stage (possible day-cases) versus two-stage procedures, primary and secondary repairs and testosterone stimulation pre-op.

Orthoplasty
Artificial erestion used to identify and correct the chordee (saline/tourniquet). Preservation of the urethral plate is desirable - incise around the plate in a U-shape and then dissect from penile shaft or dorsally plicate (TAP).

Urethroplasty
Utilising adjacent skin - vascularised onlay or tube flaps - free graft onlay/tube (buccal mucosa).

Skin cover
Dorsal preputial skin via 'button-hole' or vertical flaps.

Anterior Hypospadias (>50%)

MAGPI procedure (Duckett)
Meatal advancement and glanuloplasty. Duckett carried out >1000 precedures with a 1.2% reop. rate.

Mathieu procedure
More proximal meatus.

Onlay Island Flap

Middle and Posterior Hypospadias

Onlay Island Flap

Transverse Preputial Island Flap

Double Faced Island Flap

Buccal Mucosal Grafts - onlay or tube forms, 6 cm available in adult, vascular ++
Need to thin lamina propria prior to use.

Complex and revision hypospadias repairs often require buccal grafts and sometimes two-stage procedures.

Complications
Acute - infection, flap/graft failure, oedema, erection trauma
Chronic - fistulae (5-10%), urethral diverticulum, residual chordee, stricture, hairy urethra, meatal stenosis, BXO.
Psychological morbidity is mild.

New Developments
Polyglycolate sutures reduce fistula rate
Laser welding techniques
Synthetic collagen matrix

Epispadias

Definition	Dorsal displacement of meatus and dorsal chordee. Patients are often incontinent.
Incidence	Males 1:120000, Females 1:500000 live births
Associations	Genital deformity (bifid clitoris in female), symphyseal diastasis, VUJ abnormalities and reflux.
Classifications	Males: glanular - penopubic (commonest) - complete Females: patulous meatus - partial dorsal urethral slit - complete dorsal urethral slit.

Surgical Repair

Aims:
Achieve continence
Protect UUT's
Genital cosmesis

In males surgery includes urethroplasty and penile elongation, then delayed bladder neck reconstruction (MMK). This results in possible continence rates of 80% and 70% male potency.

Micropenis

Definition	Congenitally small penis but of normal structure. Stretched length is <1.9 cm in term newborn.
Aetiology	Usually hypogonadotropic hypogonadism. hypothalamic failure - Kallman's, Prader-Willi syndrome congenital hypopit. - GH deficiency Also hypergonadotrophic hypogonadism (primary testicular failure) Often idiopathic
Investigation	Karyotyping Serum testosterone (pre/post hCG) MRI of midbrain/hypothalamus
Treatment	Testosterone 25 mg monthly (may impair pubertal growth) Gender reassignment

Feedback
Any comments, ideas or answers? Email edu@bui.ac.uk

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Page Last Updated 11 October, 2009