INTRODUCTION
Hypospadias is one of the most common urogenital anomalies, occurring in 3 in 1000 births. It is better defined as a hypoplasia of the tissues forming the ventral aspect (ventral radius) of the penis beyond the division of the corpus spongiosum. It is charac- terized by a ventral triangular defect whose summit is the division of the corpus spongiosium, whose sides are represented by the two pillars of atretic spongiosum and whose base is the glans itself.
In the middle of this triangle sit from the tip to the base of the penis: a widely open glans, the urethral plate, which extends from the ectopic urethral mea- tus up to the glans apex, the ectopic meatus and a segment of variable length of atretic urethra (not surrounded by any spongiosum), which starts where the corpus spongiosum divides.
There are two main types of hypospadias:
쐽 The hypospadias with a distal division of the cor- pus spongiosum with little or no chordee when the penis is erected
쐽 The hypospadias with a proximal division of the corpus sponiosum with a marked degree of hypo- plasia of the tissues forming the ventral radius, marked by a significant degree of chordee The causes of hypospadias remain essentially un- known although several avenues have been explored to explain this congenital defect of the genital tubercle:
쐽 Some endocrine disorders have been described in relation to hypospadias, mainly due to an insuffi- cient secretion of androgens, or insufficient re- sponse by the target tissues. However, in very few cases can these disorders be demonstrated.
쐽 Some genetic disorders could explain why hypo- spadias may be found in several members of the same family.
쐽 Young and old mothers are more prone to carry a baby with hypospadias. Small birth-weight babies and twins also have a higher risk of presenting with a hypospadias. This could be explained by a placental insufficiency.
쐽 The significant increase of hypospadias in the population over the last 20 years raises the role of possible environmental factors such as oestrogen- like molecules, pesticides, fertilizers etc.
쐽 Abnormal or insufficient growth factors could al- so be responsible for these penile anomalies and could also explain the significant complication rate met in this surgery.
Three surgical steps characterize hypospadias sur- gery:
쐽 The correction of chordee, which is essentially the result of the atresia of the ventral radius. Deglov- ing the penis represents the first step of this sur- gery and straightens the penis in 80% cases. In 15% cases, the persistent curvature is due to an ab- normal tethering of the urethral plate and the hy- poplastic urethra onto the ventral aspect of the corpora. Lifting the urethral plate from the corpo- ra is a valuable additional manoeuvre that straightens the penis in most cases. There are still 5% cases where the penis remains bent although all the tissues forming the ventral radius have been freed. The residual chordee is due to asym- metrical corpora cavernosa and requires a dorsal corporeoplasty (dorsal shortening of the albugin- ea of the corpora cavernosa). In most cases the urethral plate can be preserved although there are situations where the urethral strip is very poor and the 2 corpora writhe around it. In these cases the urethral plate is usually sacrificed.
쐽 Once the penis is straight, the missing urethra should be replaced. The technique chosen de- pends on the size and quality of the urethral plate:
– If the urethral plate is wide and healthy, it can be tubularized following the Thiersch-Duplay technique.
– If it is too narrow to be tubularized, the Snod- grass urethrotomy is one option or additional tissue can be laid on the urethral plate using a rectangle of pediculized preputial mucosa (on- lay urethroplasty), or a flap of ventral penile skin (Mathieu procedure).
– If the segment of urethra to replace is short (<2 cm), and if the distal urethra is not hypo- plastic, a complete mobilization of the whole penile urethra may be adequate to bridge the defect. This technique (Koff), like the Thiersch- Duplay technique, has the advantage of avoid- ing the use of non-urethral tissue.
Pierre Mouriquand, Pierre-Yves Mure
Figure 51.1
From the tip to the base of the penis: the ventral as- pect of the glans is wide opened (1). The urethral plate replaces the urethra (2) and extends from the apex of the glans down to the ectopic meatus (3). Be- hind the ectopic meatus sits a segment of hypoplastic urethra not surrounded by any spongiosum (4). The division of the corpus spongiosum (5) marks the proximal limit of the malformation. It defines a tri- angular defect whose summit is the division of the corpus spongiosum, whose base is the glanular cap and whose sides are represented by the two lateral pillars of atretic spongiosum.
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Figure 51.2a–d
MAGPI Procedure
The MAGPI procedure was very fashionable in the 1980s to repair distal hypospadias. It is actually not a meatal advancement but a flattening of the glans, which gives the illusion that the meatus reaches the glans apex. Secondary retraction of the meatus is quite common and therefore this procedure has be- come less popular.
The incision line is drawn 5 mm behind the ectop- ic meatus and follows the cutanemucosal junction of the prepuce.A deep vertical incision into the glanular groove for a distance of about 1 cm opens the dorsal meatus generously. Transverse closure of the dia- mond-shaped defect that is created flattens out the glanular groove and allows a straight stream to emerge.
– If the urethral plate is not preservable, a tube needs to be made to replace the missing urethra using either a pediculized rectangle of preputial mucosa (Asopa-Duckett technique) or buccal mucosa.
– In major hypovirilization of the genital tuber- cle, the Koyanagi procedure mobilizing the whole mucosal tissue of the ventral radius and preputial hood is a reliable option to recon- struct the missing urethra. Two stage proce- dures (Bracka - Cloutier procedure) are an al- ternative for long urethroplasty using either preputial mucosa or buccal mucosa.
쐽 Once the urethra is repaired, the ventral radius of the penis needs to be reconstructed. This includes:
– Meatoplasty trying to create a slit-shaped meatus – Glanuloplasty to reconstruct the ventral aspect
of the glans
– The creation of a mucosal collar around the glans – Coverage of the reconstructed urethra (spongio-
plasty) using the lateral pillars of spongiosum – Skin cover with a redistribution of the skin shaft
bringing the excess dorsal skin to the ventrum – Some prefer to reconstruct the foreskin, others
favour circumcision.
The patient’s age at surgery for primary hypospadias repair is usually between 6 and 24 months.
Hormonal stimulation of the penis using beta hu- man chorionic gonadotrophin (βHCG) or testoste- rone or dihydrotestosterone is sometimes indicated in case of small penis or re-dosurgery. It remains un- clear how safe these treatments are on a long-term basis. General anaesthetic is the rule often associated with caudal or penile anaesthesia. Magnification is commonly used in this surgery. Coagulation is often not needed in this surgery when the tourniquet is used followed by a slightly compressive dressing.
Other surgeons prefer bipolar coagulation or adren- aline injection prior to incision. Antibiotic protocols are extremely variable from one centre to another and, here again, their efficacy needs to be proven.
Urine drainage via a suprapubic catheter, a trans- urethral bladder catheter or dripping urethral stent, varies a lot from one surgeon to another. Some even do not drain at all. The dressing is essential after this surgery and varies also. The “daisy dressing” has our favour as it is very comfortable for the patient and contains post-operative bleeding. Others prefer Op- Site dressing, silastic foam dressing or Tagaderm dressing. Post-operative pain control is essential us- ing morphine instillations, anti-inflammatory medi- cations, anticholinergic and diazepam to reduce bladder spasms.
1
2
3 5 4
Figure 51.1
Figure 51.2a–d
a b c d
Figure 51.3a–d
The ventral lip of the urethra is fixed with a holding stitch and brought forward. This allows the lateral wings of the glans to rotate to the ventrum. A sleeve approximation of the penile skin is done, excising all redundant tissue and leaving a circumcised appear-
ance. It seems that the MAGPI procedure is particu- larly well indicated when the glans is broad and flat.
No stent or catheters are required and the procedure can be done on outpatient basis.
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Figure 51.4a–d
In the Mathieu procedure, two parallel incisions are made on either side of the urethral plate up to the tip of the glans and deep down to the corpora cavernosa.
The incision line delimits a perimeatal-based skin flap that is folded over and sutured to the edges of the
urethral plate. The lateral wings of the glans are gen- erously dissected from the corpora cavernosa and approximated together producing a conical shape of the glans.
Mathieu Procedure
Figure 51.3a–d
a b c d
Figure 51.4a–d
a b c d
Figure 51.5a–e
The urethral plate is incised longitudinally on its midline from the ectopic meatus up the glans and subsequently tubularized around a Fr 8 catheter. This is the Snodgrass procedure which leaves a dorsal raw area in the urethra with a subsequently epithelize.
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Snodgrass Procedure
Figure 51.5a–c
a
b c
d e
Figure 51.6a,b
In the onlay procedure, a rectangle of preputial mu- cosa is pediculized down to the base of the penis and transferred to the ventrum of the penis to be layed on the urethral plate using interrupted 6/0 or 7/0 or a running suture.
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Onlay Procedure
Figure 51.6a,b
a
b
Figure 51.7a–d
When the urethral plate is too poor to be kept full- tube urethroplasty needs to be performed using ei- ther a pediculized rectangle of preputial flaps or a rectangle of buccal mucosa may be used. The main
disadvantage of these techniques is that a proximal circular urethral anastomosis is performed, which increases the risk of urethral stenosis.
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Figure 51.7a–d
Onlay island flap Pedicle
Epithelium to be excised
a b
c d
Figure 51.8a–e
Koff’s Urethral Mobilisation
Thiersch-Duplay Procedure
When the segment of the urethra to reconstruct is short (< 2 cm) and when the distal urethra is healthy, a full mobilisation of the penile urethra can be per- formed following Koff 's technique. In these cases the
penile urethra is detached as far proximally as neces- sary, and the it is moved upward to bring then mea- tus to the tip of the glans. The gain of length may be up to 15 mm.
Figure 51.9a–d
The incision lines follow each side of the urethral plate from the tip of the glans down to the division of the corpus spongiosum. The two wings of the glans are dissected deeply and laterally until the corpora are clearly identified. The urethral plate is tubular-
ized around a French 8 catheter for children under 3 years of age, using a 6/0 or 7/0 absorbable running suture. The neourethra is then covered by 2 wings of the glans in one or two layers.
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Figure 51.8a–e
Figure 51.9a–d
a b c d e
a b c d
CONCLUSION
Hypospadias surgery remains a difficult challenge as several factors of success remain unknown. One of the most intriguing is the variations of the “healing abilities” between patients. With the development of tissue engineering, it is hoped that urethral substitu- tion using the patient’s urethral tissue might be the future avenue to resolve the current difficulties met.
Long-term follow-up of these patients appears to be a crucial issue to assess and validate the various tech- niques currently available. The problem is how to fol- low these patients. Clinical examination of the penis is highly subjective. Assessment of the urine stream is difficult as urine flow studies are very often abnor-
mal after urethral reconstruction. At the end of the day, the experience and honesty of the pediatric urol- ogist remain the two most important factors to progress in hypospadiology. Parents should be clear- ly informed that approximately 50% of hypospadias repairs will require further surgical attention during the patient's life. Minor hypospadias do not exist and this implies that this surgery should always be per- formed by experienced paediatric urologists. Collab- oration with pediatric endocrinologists is also im- portant to increase the chances of surgical success.
Pre- and post-operative treatment may be helpful to improve the patient’s “healing abilities”.
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SELECTED BIBLIOGRAPHY
Mouriquand P, Mure PY (2001) Hypospadias. In: Gearhart J, Rink R, Mouriquand P (eds) Pediatric urology.WB Saunders, Philadelphia, pp 713–728
Mouriquand PDE, Persad R, Sharma S (1995) Hypospadias re- pair: current principles and procedures. BJU 76 [Suppl.
3] : 9–22
Snodgrass WT, Lorenzo A (2002) Tubularized incised-plate urethroplasty for proximal hypospadias. BJU Int 89 : 90–93
Duckett JW (2002) Hypospadies repair. In: Frank JD, Fearhart JP, Snyder HM III (eds) Operative pediatric urology.
Churchill Livingstone, London, pp 149–160
Snyder H (2003) The island onlay hypospadias repair. In: Hadi- di AT, Azmy AF (eds) Hypospadias surgery. Springer, Hei- delberg Berlin New York, pp 163–168
