Dr. med. Dirk Manski

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Hypospadias: Causes, Diagnosis and Treatment

Definition of Hypospadias

Hypospadias is a common congenital disease of the penis with an abnormal ventral opening of the meatus of the urethra. Hypospadias are often associated with a ventral curvature of the penis (chordee) and a deficient ventral prepuce (foreskin) with a dorsal "hood". The classification of hypospadias depends on the position of the urethral meatus:

Epidemiology of Hypospadias

1–8/1000 births. Distal hypospadias are more often. The incidence of hypospadias is increasing (see etiology).

Risk Factors for Hypospadias

Family history: about 7% of patients with hypospadias have children with hypospadias, and 14% of male siblings of the index patient have hypospadias.

Further risk factors are increased maternal age, low birth weight, and in-vitro fertilization.

Causes (Etiology) of Hypospadias

Embryology of the Male Urethra:

The urethra emerges from the urethral folds, which fuse ventrally under the influence of androgens. The fusion begins proximally in the 11th week of gestation and proceeds distally. The fusion involves endodermal and ectodermal tissue. The 5α-reductase mediates the androgen effect.

In hypospadias, malformations concern the endodermal and ectodermal tissue. An example of an ectodermal abnormality is the deficient ventral foreskin with a dorsal "hood". Endodermal abnormalities include the position of the meatus and a deficient urethra distal to the meatus with chordee formation (urethral plate).

Androgen Deficiency:

An absolute (low concentration) or relative (decreased sensitivity of the target tissue) androgen deficiency is a significant cause of hypospadias development. Many enzyme deficiencies that cause hypospadias are known, such as 5α-reductase deficiency or defects of the androgen receptor. In 10–70% of severe proximal hypospadias, an enzyme deficiency or hormonal disease affecting the androgens can be found.

Genetics:

Hypospadias is a polygenetic disease, this can be concluded from the family history and twin studies. The risk of hypospadias in brothers of index patients is about 10–14%. In addition to the known enzyme defects (see above), most genes involved in the etiology of hypospadias are still unknown. Hypospadias is also a symptom in several genetic syndromes such as Denys-Drash syndrome (postnatal nephrotic syndrome and Wilms tumor due to mutation of WT-1 gene), Opitz-G/BBB syndrome (craniofacial malformations, malformations of the larynx and pharynx and, less commonly, ventral midline defects), Smith-Lemli-Opitz syndrome (metabolic disorder of cholesterol biosynthesis with multiple abnormalities), Paetau syndrome (trisomy 13), and hand-foot-genital syndrome (malformations of the extremities and genital organs).

Environmental Factors:

Environmental Factors:

The increasing incidence in industrialized countries argues for environmental toxins, which increase the risk for hypospadias and other diseases ( male infertility, cryptorchidism, premature births, testicular cancer). Numerous substances (endocrine disruptors) in plastics and pesticides are discussed as causal substances (DeToni et al., 2019) (Rodprasert et al., 2021).

Penis Curvature in Hypospadias:

The chordee (urethral plate) has previously been considered the cause of ventral penile curvature in hypospadias; many studies now question this. Penile curvature is now considered a part of normal penile development. In addition, the conservation and utilization of the urethral plate is essential for hypospadias operations popularized by Snodgrass. In most cases, the curvature of the penis can be corrected using the technique of Nesbit.

Signs and Symptoms

Hypospadias is usually asymptomatic. Distal hypospadias without curvature do not cause any functional limitations and are "only" a cosmetic problem due to parents' and patients' expectations [fig. asymptomatic hypospadias of an adult]. Proximal hypospadias can disturb the control of the urine stream; an accompanying curvature can hinder sexual intercourse.

Associated congenital disorders:

Cryptorchidism or disorders of sex development in 7%, bifid penis, inguinal hernia in 12%, mental retardation (6%) and malformations of the heart (5%), musculoskeletal system (3%), or anal canal (1%), see also section etiology above.

Diagnostic workup of Hypospadias

Basic Investigations:

In addition to a careful physical examination (position of the meatus, open processus vaginalis, cryptorchidism, signs of DSD), ultrasound imaging of the urinary organs is necessary. An intravenous urography or micturition cystourethrography may be needed if anomalies are identified.

Diagnosis in Patients with Proximal Hypospadias or Familial Disease:

Disorders of sex development are more prevalent in patients with proximal hypospadias, the following evaluations are necessary

Further diagnostics and referral to a DSD center may be appropriate depending on the findings.

Treatment of Hypospadias

Time and indication:

Concerning wound healing, the ideal time for surgery is the 12th to 18th month of life. Surgery in young children is uncontroversial in marked hypospadias (proximal forms) and hypospadias with relevant urethral stenosis. Distal hypospadias without concomitant pathology, the patient's ability to consent should be awaited (Carmack et al., 2016). In intersex patients, hypospadias surgery (as non-vital gender reassignment surgery) is not allowed before puberty without the consent of the family court.

Principals of Hypospadias Surgery

Please see also the section Urologic Surgery/General principles of hypospadias operations.

Orthoplasty

Assessment and management of penile curvature is done after an after artificial erection of the penis during surgery. In most cases, the curvature of the penis is corrected using the technique of Nesbit. In severe cases, grafting of the tunica albuginea helps straighten the penis. Resection of the chordee is only rarely performed, and for tubularized incised plate (TIP) urethroplasty, conservation of the urethral plate is mandatory.

Urethroplasty

Urethroplasty is the reconstruction of the missing distal urethra. The surgical techniques described below differ primarily in urethroplasty: application of flaps, incision of the urethral plate or free oral mucosa transplants.

Neourethral coverage:

A second layer of tissue covers the neourethra and prevents the formation of fistulas. A pedicled subcutaneous (dartos) flap is often raised from preputial, penile, or scrotal skin.

Meatoplasty and glanuloplasty:

Meatoplasty and glanuloplasty are the reconstruction of the meatus and the glans to achieve a meatus at the tip of the penis with a vertical slit.

Skin closure:

Skin coverage of the penile shaft is achieved with various techniques (e.g., transfer of penile skin).

MAGPI Hypospadias Operation:

MAGPI is the acronym for Meatal advancement and glanuloplasty (Duckett, 1981b). The MAGPI technique is only suitable for minor distal hypospadias (cosmetic indication). For technique and complications, see Chapter Urologic Surgery/MAGPI-technique for hypospadias repair.

Tubularized incised plate (TIP) Urethroplasty

TIP urethroplasty is suitable for distal and proximal penile hypospadias (Snodgrass, 1994). The TIP urethroplasty is considered technically simple and has a low complication rate; the cosmetic result of the glans and the meatus is good. Furthermore, the TIP urethroplasty is useful for re-operation with preserved urethral plate. The urethral plate is not removed but deeply and longitudinally incised. After mobilization and tubularization, the urethral plate is closed around a catheter. A ventral curvature is corrected using the Nesbit technique. If the urethral plate is found to be too narrow for primary tubularization, buccal mucosa is used as a ventral inlay graft. Please see section Urologic Surgery/Tubularized incised plate (TIP) urethroplasty for details.

Mathieu Hypospadias Repair

The Mathieu hypospadias repair is a good option for distal penile hypospadias (Mathieu, 1932). A rectangle of skin over the proximal urethra is raised and folded distally. To avoid a horizontal meatus, a modification of the original technique with V-incision of the flap exists (MAVIS = Mathieu and V incision sutured). The most common complications are unfavorable meatal cosmetics, skin flap necrosis with fistula, or stricture of the urethral meatus. Please see section Urologic Surgery/Mathieu hypospadias repair for details.

Island Flap Hypospadias Repair

The island flap hypospadias repair is suitable for distal and middle penile hypospadias (Duckett, 1981a). The island flap is raised from the prepuce: the pedicled flap consists of the inner leaf of the prepuce with Tunica dartos. The flap is rotated around the penis and used in an onlay technique with a preserved urethral plate. If a resection of a chordee has been necessary, a tubular island flap is needed. Please see section Urologic Surgery/Island flap hypospadias surgery for details.

Two-stage Hypospadias Repair

Indications for a two-stage hypospadias repair are severe proximal hypospadias and situations after failed hypospadias surgery. Please see section Urologic Surgery/Two-stage hypospadias repair for details.

Hypospadias Repair with a Free Oral Mucosa Graft

Indications for using a free oral mucosa graft are situations after failed hypospadias surgery.








Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

References

Baskin 2000 BASKIN, L. S.: Hypospadias and urethral development.
In: J Urol
163 (2000), Nr. 3, S. 951–6

A. Carmack, L. Notini, and B. D. Earp, “Should Surgery for Hypospadias Be Performed Before An Age of Consent?,” J Sex Research, vol. 53, no. 8, pp. 1047–1058, 2016.

Duckett 1981a DUCKETT, J. W.: The island flap technique for hypospadias repair.
In: Urol Clin North Am
8 (1981), Nr. 3, S. 503–11

Duckett 1981b DUCKETT, J. W.: MAGPI (meatoplasty and glanuloplasty): a procedure for subcoronal hypospadias.
In: Urol Clin North Am
8 (1981), Nr. 3, S. 513–9

Mathieu 1932 MATHIEU, P.: Traitement en un temps de l’hypospadias balanique ou juxtabalanique.
In: J Chir
39 (1932), S. 481?486

Mouriquand u.a. 1995 MOURIQUAND, P. D. ; PERSAD, R. ; SHARMA, S.: Hypospadias repair: current principles and procedures.
In: Br J Urol
76 Suppl 3 (1995), S. 9–22

C. Radmayr, G. Bogaert, H. S. Dogan, and Tekg&uuml, “EAU Guidelines: Paediatric Urology,” 2022. [Online]. Available: https://uroweb.org/guidelines/paediatric-urology/.

W. Rodprasert, J. Toppari, and H. E. Virtanen, “Endocrine Disrupting Chemicals and Reproductive Health in Boys and Men.,” Front Endocrinol., vol. 12, p. 706532, 2021.

Snodgrass 1994 SNODGRASS, W.: Tubularized, incised plate urethroplasty for distal hypospadias.
In: J Urol
151 (1994), Nr. 2, S. 464–5



  Deutsche Version: Ursachen der Hypospadie und Diagnose und Therapie der Hypospadie