Hypospadias. Laurence S. Baskin, M.D. Chief, Pediatric Urology University of California, San Francisco

Transcription

1 UCSF Pediatric Urology Center for the Study and Treatment of Hypospadias Written for Pediatricians, Family Practitioners, Nurse Practitioners, Health Care Workers and Families of Patients with Hypospadias Hypospadias Laurence S. Baskin, M.D. Chief, Pediatric Urology University of California, San Francisco Adapted from the Handbook of Pediatric Urology Lipponcott-Raven, 1997, Baskin, Kogan and Duckett I. Introduction A. Hypospadias is a congenital defect of the penis, resulting in incomplete development of the anterior urethra, corpora cavernosa and prepuce (foreskin). B. Clinically, the hypospadiac urethral meatus does not cause significant urinary symptoms other than a urinary stream which may be deflected in a downward fashion. C. Hypospadias is also associated with penile curvature and may result in infertility secondary to difficulty in semen delivery. II. Embryology A. At one month gestation the male and female genitalia are essentially indistinguishable. B. Under the influence of testosterone the male external genitalia become masculinized.

2 C. By the end of the first trimester and the beginning of the 2nd trimester the penile urethra and accompanying prepuce are completely formed. D. Abnormalities in this development can lead to hypospadias and associated penile anomalies. E. In hypospadias, incomplete development of the glandular urethra does not allow the preputial folds to fuse. F. Consequently, in hypospadias the foreskin is absent on the ventrum and there is excessive foreskin on the dorsal surface (dorsal preputial hood). III. Classification A. Hypospadias can be classified as to the location of the urethral meatus without taking into account penile curvature. B. A more useful surgical classification is the location of the urethral meatus after penile straightening where: 1. 50% of the patients will have anterior hypospadias with the meatus on the glans or subcoronal (Figure 1) % will have the urethral meatus on the penile shaft % will have the meatus between the perineum and the penoscrotal junction. IV. Incidence, Genetics and Etilogy A. Hypospadias occurs in ~one per three hundred live male births. Recent reports in Europe and the United States suggest that the rate of hypospadias is increasing. B. There is a 14% incidence in male siblings and an 8% incidence in offspring. C. Most cases of hypospadias do not have an identifiable cause. Rare cases can be attributed to abnormalities in androgen metabolism (Type II 5? reductase deficiency) or defects in the androgen receptor. Unproven theories explaining hypospadias currently under study are genetic and environment factors such as endocrine disrupters or environmental toxins.

3 V. Associated Anomalies A. Undescended testes occur in ~9% of patients with hypospadias. B. An increased incidence of up to 30% in patients with penoscrotal or more severe hypospadias. C. Inguinal hernias also occur in ~9% of patients with hypospadias. D. A utricle or Mullerian remnant in the posterior urethra is found in a high percentage of patients with severe hypospadias. E. Associated urinary tract anomalies are infrequent in patients with isolated hypospadias because the external genitalia are formed much later than the kidneys, ureter and bladder. F. Patients with hypospadias and an undescended testicle or an inguinal hernia do not need further urinary tract evaluation such as an ultrasound or echocardiogram. G. Patients who have hypospadias in association with other organ system anomalies such as a cardiac murmur, imperforate anus or pyloric stenosis require renal and bladder imaging with an abdominal ultrasound. H. Patients with severe hypospadias and undescended testes should be investigated for intersex with a karyotype and further endocrinologic work-up. VI. Treatment of Hypospadias A. There are five basic phases for the successful reconstruction of the hypospadiac penis: 1) Creation of a normal urethral meatus and glans penis. 2) A straight penis. 3) A normal urethra. 4) Skin covering. 5) Normal position of the scrotum in relationship to the penis. VII. Timing of Surgery A. Hypospadias surgery is best performed between the ages of six months and eighteen months, prior to toilet training and during the

4 psychologic window when genital awareness has not been recognized by the patient. B. Outpatient surgery is now the standard of care. The majority of hypospadiac defects can be repaired in a single-stage operation, with severe cases requiring a staged procedure. Early hypospadias repair with minimal hospitalization helps to avoid separation anxiety and castration fears. VIII. Anaesthesia A. Hypospadias surgery is performed under general anesthesia. B. A penile nerve block or a caudal supplementation is standard to minimize post-operative discomfort. IX. Hypospadias Operations Hundreds of techniques to correct hypospadias have been published in the medical literature. Some of the standard repairs are listed below. A. Meatal advancement and glanuloplasty procedure (MAGPI). B. Mathieu procedure or Flip-Flap procedure. C. Primary closure of the urethral plate with and without incision. D. Onlay island flap procedure. E. Transverse tubularized island flap. F. Buccal mucosa grafts (taken from the inside of the cheek) can be used for urethral replacement typically in a secondary procedure when local vascular flaps have failed. F. Straightening the penis can be performed with a dorsal tunica plication procedure. X. Complications of Hypospadias Surgery A. Urethral cutaneous fistula. 1. Urethral cutaneous fistula consists of a communication between the new urethra and the penile skin, typically allowing the urine to come out through two separate holes. 2. Fistulas require operative closure ~ 6 months after the initial operation when tissue swelling has subsided.

5 B. Meatal stenosis 1. Stricturing of the new urethra which can occur anywhere along the urethroplasty, but most commonly occurs in the glans penis. C. Urethral diverticulum 1. A large outpouching or ballooning of the urethra secondary to too large of a urethroplasty or an obstruction distally (i.e. meatal stenosis). D. Superficial skin loss 1. A relatively common complication after hypospadias surgery and typically will heal spontaneously without the need for further surgical intervention by secondary penile skin granulation. This can be treated with local wound care and daily bathing. E. Residual penile curvature. If severe reoperation with penile straightening is required. XI. Postoperative Hypospadias Care A. Anterior hypospadias repair such as the MAGPI are often done without the use of a drippy stent or catheter and require no special treatment. B. More severe hypospadias requires the use of an indwelling drippy stent which is typically removed 7-14 days after surgery by cutting a stitch that secures the urethral catheter to the glans penis. C. Prophylactic doses of antibiotics such as Bactrim or Nitrofurantoin are often prescribed while the stent is in place to keep the urine sterile. D. Postoperative Symptoms Include: 1. Bladder spasms which can be treated with Ditropan (oxybutynin).

6 2. Urinary retention is uncommon, but can occur secondary to a stent malfunction such as blockage or kinking. 3. Postoperative pain is controlled with Tylenol and Tylenol and codeine elixir. E. Dressings 1. The most common dressing used after hypospadias is a plastic dressing such as Tegaderm which is used with gauze to sandwich the penis onto the abdomen and is typically removed at home 2-3 days after surgery. See Hypospadias Handout for Figures References 2001 Akman, Y., W. Liu, Y.W. Li and L.S. Baskin, Penile anatomy under the pubic arch: reconstructive implications. J Urol, (1): p Baskin, L.S., Hypospadias: A critical analysis of cosmetic outcomes using photography. British Journal of Urology, Internatioinal, : p Baskin, L.S., A. Erol, P. Jegatheesan, Y. Li, W. Liu and G.R. Cunha, Urethral seam formation and hypospadias. Cell Tissue Res, (3): p Baskin, L.S., K. Himes and T. Colborn, Hypospadias and endocrine disruption: is there a connection? Environ Health Perspect, (11): p Baskin, L.S., Hypospadias: Anatomy, embriology and Reconstructive Techniques. Brazilian Journal of Urology, (6): p Baskin, L.S., Hypospadias and urethral development. J Urol, (3): p

7 Baskin, L.S., Hypospadias Frontiers. Pediatrics Current Medical Literature, (4): p Baskin, L.S., A. Erol, Y.W. Li and W.H. Liu, Anatomy of the neurovascular bundle: is safe mobilization possible? J Urol, (3 Pt 2): p Erol, A., L.S. Baskin, Y.W. Li and W.H. Liu, Anatomical studies of the urethral plate: why preservation of the urethral plate is important in hypospadias repair. BJU Int, (6): p Kurzrock, E.A., P. Jegatheesan, G.R. Cunha and L.S. Baskin, Urethral development in the fetal rabbit and induction of hypospadias: a model for human development. J Urol, (5): p Baskin, L.S., Penile curvature, in Reconstructive and Plastic Surgery of the External Genitalia: Adult and Pediatric, R. Ehrlich and G. Alter, Editors. 1999, Saunders: Philadelphia. Baskin, L.S., Fetal genital anatomy reconstructive implications. J Urol, (2): p Baskin, L.S., A. Erol, Y.W. Li, W.H. Liu, E. Kurzrock and G.R. Cunha, Anatomical studies of the human clitoris. J Urol, (3 Pt 2): p Hinds, A. and L.S. Baskin, Child sexual abuse: what the urologist needs to know. J Urol, (2): p Kurzrock, E.A., L.S. Baskin and G.R. Cunha, Ontogeny of the male urethra: theory of endodermal differentiation. Differentiation, (2): p Kurzrock, E.A., L.S. Baskin, Y. Li and G.R. Cunha, Epithelialmesenchymal interactions in development of the mouse fetal genital tubercle. Cells Tissues Organs, (3): p Baskin, L.S. and J.W. Duckett, Hypospadias, in Pediatric Surgery, J. O'Neil, Editor. 1998, Mosby: St. Louis.

8 Baskin, L.S. and J.W. Duckett, Hypospadias: Long-term outcome, in Long-Term Outcome Pediatric Surgery, P. Mouriquand, Editor. 1998, Saunders: Philadelphia. Baskin, L.S., A. Erol, Y.W. Li and G.R. Cunha, Anatomical studies of hypospadias. J Urol, (3 Pt 2): p ; discussion Baskin, L.S. and B.A. Kogan, Urethral anomalies and obstruction, in Urologic surgery in infants and children, L. King, Editor. 1998, Saunders: Philadelphia. Baskin, L.S. and T.F. Lue, The correction of congenital penile curvature in young men. Br J Urol, (6): p Baskin, L.S., D.A. Canning, H.M. Snyder, 3rd and J.W. Duckett, Jr., Surgical repair of urethral circumcision injuries. J Urol, (6): p Baskin, L.S., Y.T. Lee and G.R. Cunha, Neuroanatomical ontogeny of the human fetal penis. Br J Urol, (4): p Baskin, L.S., R.S. Sutherland, M.J. DiSandro, S.W. Hayward, J. Lipschutz and G.R. Cunha, The effect of testosterone on androgen receptors and human penile growth. J Urol, (3 Pt 2): p Baskin, L.S., Controversies in Hypospadias Surgery: The Urethral Plate, Part 2, in Dialogues in Pediatric Urology, R. Ehrlich, Editor. 1996, Miller: New York. Baskin, L.S., Controversies in Hypospadias Surgery: Penile Curvature, Part 1, in Dialogues in Pediatric Urology, R. Ehrlich, Editor. 1996, Miller: New York. Baskin, L.S., D.A. Canning, H.M. Snyder and J.W. Duckett, Treating complications of circumcision. Pediatr Emerg Care, (1): p

9 Baskin, L.S. and J.W. Duckett, Hypospadias, in Adult and Pediatric Urology, J. Gillenwater, et al., Editors. 1996, Mosby: St. Louis. Baskin, L.S. and J.W. Duckett, The Versatility of the Onlay Island Flap Procedure, in New Techniques in Reconstructive Urology, J. McAninch, Editor. 1996, Igaku-Shion: New York. Baskin, L.S., J.W. Duckett and T.F. Lue, Penile curvature. Urology, (3): p Sides, D., R.B. Goldstein, L. Baskin and B.C. Kleiner, Prenatal Diagnosis of Hypospadias. Journal of Ultrasound in Medicine, (11): p Sutherland, R.S., B.A. Kogan, L.S. Baskin, R.A. Mevorach, F. Conte, S.L. Kaplan and M.M. Grumbach, The effect of prepubertal androgen exposure on adult penile length. J Urol, (2 Pt 2): p ; discussion Baskin, L.S. and J.W. Duckett, The use of bucal mucosa in urethral reconstruction, in Advances in Urology, M.a. Bloom, Editor. 1995, Mosby. Baskin, L.S. and J.W. Duckett, Buccal mucosa grafts in hypospadias surgery. Br J Urol, Suppl 3: p Baskin, L.S. and J.W. Duckett, Dorsal tunica albuginea plication for hypospadias curvature. J Urol, (6): p Baskin, L.S. and J.W. Duckett, Complete Vaginal Reconstruction, in Dialogues in Pediatric Urology. 1994, Miller. Baskin, L.S., J.W. Duckett, K. Ueoka, J. Seibold and H.M. Snyder, 3rd, Changing concepts of hypospadias curvature lead to more onlay island flap procedures. J Urol, (1): p

10 Duckett, J.W. and L.S. Baskin, Genitoplasty for intersex anomalies. Eur J Pediatr, (Suppl 2): p. S80-4.