02. Congenital anomalies of front abdominal wall

 1. Gastroschisis and omphalocele

Plan:

1.   Gastroschisis and Omphalocele.

2.   Inguinal hernias

3.   Umbilical hernias

4.   Cryptorchidism

Gastroschisis and omphalocele are among the most frequently encountered congenital anomalies in pediatric surgery. Combined incidence of these anomalies is 1 in 2000 births, which means, for example, that a pediatric surgeon will see 2 such babies for every 1 born with esophageal atresia or tracheoesophageal fistula.

 

 

Fig. Gross appearance of gastroschisis. Note herniation to the right of the umbilicus and lack of membranous covering associated with edema of the bowel and an exudative peel

 

Omphalocele (exomphalos) is characterized by herniation of intraabdominal contents through a full-thickness umbilical defect which is covered by a sac composed of peritoneum internally and umbilical cord amnion externally. The umbilical vessels are usually spread out over the sac.

Gastroschisis is characterized by a defect in the abdominal wall, 1 to 5 cm in diameter, usually just to the right of the umbilicus. The herniated viscera are not covered by a sac and the bowel is usually non-rotated.

 

 

 

Frequency. Exomphalos occurs in between 1 in 4000 and 1 in 10000 live births. The incidence of gastroschisis is of about 1 in 5000.

Sex. Exomphalos is more common in males than females, with a sex ratio of 3:2, but gastroschisis occurs equally.

Causes of omphalocele and gastroschisis. Factors associated with high-risk pregnancies, such as maternal illness and infection, drug use, smoking, and genetic abnormalities, also are associated with the birth of babies with omphalocele and gastroschisis. These factors contribute to placental insufficiency and the birth of small for gestational age (SGA) or premature babies, among whom gastroschisis and omphalocele most commonly occur.

Folic acid deficiency, hypoxia, and salicylates have caused laboratory rats to develop abdominal wall defects, but the clinical significance of these experiments is conjectural. Certainly, elevation of maternal serum alpha-fetoprotein (MSAFP) warrants investigation by high-resolution sonography to determine if any structural abnormalities are present in the fetus. If such abnormalities are present and associated with an omphalocele, perform amniocentesis to check for a genetic abnormality.

Embryology. The human embryo initially is disc-shaped and composed of 2 cell layers. It acquires a third cell layer as it grows above the umbilical ring and becomes cylindrical by elongation and inward folding. The body folds (cephalic, caudal, lateral) meet in the center of the embryo where the amnion invests the yolk sac. Defective development at this critical location results in a spectrum of abdominal wall defects. By the sixth week, rapid growth of the midgut causes a physiologic hernia of the intestine through the umbilical ring. The intestine returns to the abdominal cavity during the tenth week, and rotation and fixation of the midgut occur. This process does not occur in babies with gastroschisis or omphalocele, resulting in an increased risk of midgut volvulus.

Pathogenesis of omphalocele and gastroschisis

Abdominal wall defects occur as a result of failure of the mesoderm to replace the body stalk, which persists in a regioormally occupied by somatopleure. Embryonic dysplasia causes insufficient outgrowth at the umbilical ring. Decreased apoptotic cell death and underdevelopment of the mesodermal cell compartment cause enlargement of the umbilical ring’s diameter. The amnion does not apply itself to the yolk sac or connecting stalk but remains at the margin of the body wall defect, causing faulty development of the umbilical cord and a persistent communication between the intraembryonic body cavity and the extraembryonic coelom.

In babies with omphalocele, failure of central fusion at the umbilical ring by growth of the mesoderm causes defective abdominal wall closure and persistent herniation of the midgut.

Possible explanations of the embryology of abdominal wall defect in gastroschisis include the following:

Ø    According to Duhamel’s theory, gastroschisis occurs as a result of a localized teratogenic incident which affects the normal differentiation of the periumbilical mesoderm.

Ø    De Vries argues that a defect in involution of the right umbilical vein results in local ischaemia, resulting iecrosis of the periumbilical abdominal wall.

Prenatal diagnostic procedures.

Lab studies.

Prenatal diagnosis of abdominal wall defects can be made by detection of an elevation in maternal serum alpha-fetoprotein (MSAPF) during the second trimester. MSAPF levels are greater in gastroschisis than in omphalocele.

MSAPF also is increased in spina bifida, which additionally demonstrates an increased ratio of acetylcholinesterase and pseudocholinesterase.

Imaging studies.

Fetal sonography may detect a genetic abnormality, with identification of a structural marker of the karyotypic abnormality.

Fetal echocardiography also may identify a cardiac abnormality.

Confirm positive findings suggestive of a genetic abnormality by amniocentesis.

If serial ultrasounds show dilatation and thickening of the intestine in a baby with gastroschisis, and if lung maturity can be verified by amniocentesis, delivery is induced.

Fig. Prenatal ultrasonography of a fetus with a giant omphalocele. The extraperitoneal liver is indicated by the black arrow. The membrane covering the omphalocele is indicated by the white arrow. Ascites is seen within the sac

 

Fig. Prenatal ultrafast high resolution MRI of a fetus with a giant omphalocele. The covering membrane is indicated by the white arrow. The liver contained in the sac is indicated by the black arrow

Physical examinations: omphalocele.

Usually, neonates with intact omphalocele are in no distress, unless associated pulmonary hypoplasia is present. The size of the abdominal wall defect ranges from 4-12 cm. The abdominal viscera are contained within a translucent sac, which is composed of amnion, Wharton jelly, and peritoneum. The umbilical vessels radiate onto the wall of the sac. In 50% of cases, the liver, spleen, and ovaries or testes accompany the extruded midgut.

The omphalocele sac is usually intact, although it may be ruptured in 10-20% of cases. Rupture may occur in utero or during or after delivery.

Giant omphaloceles have large central or epigastric defects. The liver is centrally located and entirely contained within the omphalocele sac. The abdominal cavity is small and undeveloped, and operative closure is very difficult. The thoracic cavity is also small. Associated pulmonary hypoplasia or restrictive lung disease may be present.

Fig.  Giant omphalocele with bowel and liver (black arrow) seen within the sac

Although the ease of surgical reduction and repair correlate with the size of the abdominal wall defect, a small omphalocele is no guarantee of an uncomplicated clinical course. Examine the baby carefully to detect any associated problems, such as Beckwith-Wiedemann syndrome, chromosomal abnormalities, congenital heart disease, or other associated malformations. Paradoxically, babies with small (unimpressive) omphaloceles are most likely to have associated abnormalities.

Syndrome omphaloceles

Beckwith-Wiedemann syndrome

Babies with the Beckwith-Wiedemann syndrome (ie, exomphalos, macroglossia, gigantism) have large, rounded facial features, hypoglycemia from hyperplasia of the pancreatic islet cells, and visceromegaly. They may have genitourinary abnormalities, and they are at risk for development of Wilms tumors, liver tumors (hepatoblastoma), and adrenocortical neoplasms. The principal danger in these patients is postnatal hypoglycaemia (due to pancreatic islet hyperplasia) causing cerebral damage.Early administration of glucose can prevent serious sequelae.

Pentalogy of Cantrell

This malformation of the upper abdominal fold involves anterior diaphragm and pericardial defects, a short bifid sternum, and cardiac defects associated with an omphalocele sac or, at least, hypotrophic epigastric skin. Coverage of the omphalocele during evaluation of the cardiac defects allows subsequent complete repair of cardiac, diaphragmatic, and pericardial defects.

Vesicointestinal fissure (cloacal extrophy)

This malformation of the lower fold has an inferior-sited omphalocele, exstrophy of the cecum between the hemibladders, diastasis of the symphysis pubis, a short distal colon, no rectum, a shortened small bowel, and, occasionally, meningosacral anomalies. Many infants now survive following multiple corrective intestinal and urinary tract procedures.

Physical examinations: Gastroschisis

Gastroschisis, not covered by a sac, has extracorporeal viscera exposed to the amniotic cavity in utero or to the atmosphere postnatally. The abdominal wall defect is fairly uniform in size and location: a 5-cm vertical opening immediately to the right and inferior of the umbilical cord.

Gastroschisis is rarely associated with abnormalities outside the gastrointestinal system. Atresia, often resulting from local ischaemia at the neck of the sac, is by far the most common abnormality associated with gastroschisis, with an incidence of between 11 and 23 per cent.

Intestinal inflammation.

Intestinal inflammation may occur with either gastroschisis or ruptured omphalocele.

The eviscerated intestine may be either normal or abnormal in structure and function. The degree of abnormality depends upon the extent of the inflammatory and ischemic injury, manifested by shortened length and surface exudate (peel), which is related to the composition and duration of the intestine’s exposure to the amniotic fluid and fetal urine.

Inflamed intestine is thick and edematous, the loops of bowel are matted together, and the mesentery is congested and foreshortened.

Histologically, atrophy of the myenteric ganglion cells is seen.

The intestine is dysmotile, with prolonged transit time and decreased absorption of carbohydrate, fat, and protein. These deleterious effects remit as the inflammation resolves, usually in 4-6 weeks. During this time, total parenteral nutrition (TPN) is required.

Treatment

The major problems with gastroschisis are reduction of the inflamed viscera into the abdomen and maintenance of effective nutrition. The 2 major problems in the management of omphaloceles are closure of the defect without undue tension and treatment of associated anomalies, particularly cardiac anomalies and pulmonary hypoplasia. Associated anomalies must swiftly be stabilized prior to operation.

Preoperative treatment

Intact omphalocele

Elective, preterm cesarean delivery is recommended for infants with large omphaloceles to avoid damage to the sac from labor and delivery.

Give nothing by mouth (NPO) pending operative repair. Administer maintenance IV fluids, and cover the omphalocele sac with sterile saline-soaked gauze and with plastic wrap, using sterile technique.

Give prophylactic antibiotics preoperatively, because of the possibility of an associated intestinal anomaly.

Closure of a small or moderate size omphalocele usually is accomplished without difficulty. Closure of a giant omphalocele that contains the liver can be very challenging.

A ruptured omphalocele is treated like gastroschisis.

Gastroschisis

The greatest loss of contractility and mucosal function of the bowel and the fibrous coating of the bowel in gastroschisis occurs late in gestation. Elective preterm cesarean delivery may obviate late-term intestinal damage.

Respiratory distress ieonates with gastroschisis may respond to gastric decompression, although endotracheal intubation may still be needed.

The baby should be placed under a radiant heater, and the exposed intestines should be covered with plastic wrap and supported to avoid excessive traction on the mesentery.

Wide-spectrum antibiotics should be administered.

Fluid, electrolyte, and heat losses must be minimized and corrected. The fluid requirements for an infant with gastroschisis are 4-8 times the usual requirements for the first 24 hours of life due to visceral inflammation. Maintenance of a urinary output of 0,5 – 1 ml/kg/h by closely monitored administration of crystalloids maintains proper hydration. The inflamed peritoneal and intestine capillary membranes stabilize in 12-18 hours after operation, and the fluid requirements then markedly decrease. When the capillary membrane stabilizes, exogenous albumin may be administered to elevate serum levels.

Surgical Care.

Primary closure (Hey, 1803) of both fascia and skin is the best approach for both omphalocele and gastroschisis and is indicated for infants with small to moderate isolated intestinal evistration. However, increased intra-abdominal pressure with compromised ventilation can produce abdominal compartment syndrome, characterized by inferior vena caval compression, intestinal and renal poor perfusion, and lower extremity edema. Enlarging the abdominal cavity by stretching the abdominal wall, decompression of the stomach, irrigation of the intestine and colon to remove meconium, and postoperative use of ventilators and muscle relaxants frequently allows primary closure. The sac is removed at the fascial edge.

Skin-Flap Closure. Healing may be hastened by surgically mobilizing skin flaps sufficient to cover the omphalocele sac, thereby obtaining closure of the abdominal wall defect in a way comparable to closing a burn wound with skin grafts (Gross technique). This, however, results in the creation of a ventral hernia.

 

Staged Reduction. In 1967, Schuster developed a technique that may be used in the initial treatment of a baby with a giant omphalocele or in correcting the ventral hernia created by skin flap closure. An incision is made along the skin-sac junction of the abdominal wall defect, which is enlarged in the midline. The anterior rectus fascia is exposed from the xiphoid to the pubis, and Teflon sheets are sutured to its medial edge. The Teflon sheets are then closed over the omphalocele sac and gradually tightened, approximating the rectus muscles over the abdominal viscera.

Fig. Amnioinversion technique. (a) Dissection of the skin from the amnion, the identification of the fascia, and the raising of skin flaps. This is performed circumferentially around the omphalocele, extends several centimeters beyond the edge of the fascia, and keeps the amnion intact. (b) The suturing of artificial mesh to the fascia. This is performed 1–2 cm from the edge of the mesh using a running polypropylene suture. The cuff of mesh is secured to the anterior abdominal wall fascia with absorbable suture in an onlay fashion. Tissue in-growth from the fascia through the mesh helps to secure it in place. (c) Sequential tightening of the mesh using horizontal mattress silk sutures through the mesh to remove the slack and reduce the omphalocele. (d) After several reductions, the omphalocele is at the level of the fascia. Once the fascia is touching, the fascia is closed and the mesh removed

Non-surgical treatment (Grob, 1957).

Grob introduced the use of mercurochrome as an escharotic for scarifying the intact sac of a giant omphalocele. However, the development of mercury poisoning terminated its use. Chemical dressings using silver sulfadiazine with the complication of leukopenia, povidone-iodine solution with the complication of hypothyroidism, silver nitrate solution (0.5%) with the complication of argyrism, and gentian violet have served as agents to protect against infection while the sac epithelializes. Only life-threatening associated conditions, poor probability of survival in infants, or failure of better means of coverage warrant this method today.

 

External coverage with pigskin, skinlike polymer membrane, or human amniotic membranes can be used adjunctively in the treatment of giant omphalocele or after failed primary therapy.

 

Figure : Traditional silo bag.

 

 

Fig.Appropriate placement of silo. Bowel is placed in the smallest size silo that will accommodate it. Viable and well-perfused bowel visible within silo without much bottle-necking at level of defect

Postoperative care

Diet. Babies with omphalocele usually do not require special formulas; their intestines are typically normal, with the exception of occasional atresias.

Babies with gastroschisis, typically require special elemental, crystalline amino acid, or protein hydrolysate formulas with nonlactose carbohydrate and medium-chain triglycerides because of the associated gut inflammation and resultant tendency towards substrate malabsorption and allergy.

Activity. A child with a repaired giant omphalocele has an epigastric liver. In this location, the liver is more vulnerable to trauma. Avoidance of contact sports is prudent.

Further Inpatient Care. Babies with omphalocele usually have rapid return of intestinal function after surgical repair, even if intestinal atresia occurs concomitantly, because no associated gut inflammation is present.

Babies with giant omphaloceles usually have a protracted hospital course; and overall morbidity and mortality is higher for these patients. Multiple procedures are necessary to obtain closure of the abdominal wall defect.

In patients with gastroschisis, even if primary closure of the abdominal wall defect is obtained, a period of several weeks of intestinal dysfunction (ileus) usually follows, as a result of associated gut inflammation. In this situation, parenteral nutrition is essential, followed by the gradual introduction of enteral feedings. Continuous drip feedings usually are tolerated optimally.

Further Outpatient Care:

After hospital discharge, babies require close follow-up care to assess growth and weight gain.

Patients usually have gastroesophageal reflux and may require medical therapy, but fundoplication should not be necessary.

Complications

Complications of omphalocele can be classified into early and late (Tables 66.2 and 66.3). Some, such as pulmonary hypoplasia and subsequent chronic lung disease, are related to the disease process. As all infants with omphalocele are malrotated, there is a risk of midgut volvulus, but this occurs rarely. Other complications are related to treatment or the intensity of medical therapy, such as delayed enteral nutrition resulting in cholestasis, episodes of line sepsis, or developmental delay and hypotonia. Early complications such as the exacerbation of respiratory insufficiency or renal failure are related to the surgical closure of the abdomen being too tight, resulting in abdominal competition and decreased renal perfusion.

Late complications, such as hernia and GERD, might also be the result of increased intra-abdominal pressure. These complications highlight the need to select the appropriate treatment modality based on the size of the omphalocele and the associated comorbidities.

Survival of patients with omphalocele is largely related to

associated anomalies. These infants are also at risk for chromosomal abnormalities and other comorbidities, such as pulmonary

 

Omphalocele Complications

·                    Intestinal infection

·                    Death of the intestinal tissue related to dryness and trauma to the unprotected intestine

·                    Poor healing of the abdominal wound usually results in a ventral hernia, which may require secondary surgical repair.

·                    Even with successful repair, which usually requires a synthetic patch, and good clinical outcome, the location of the child’s liver is central, directly beneath the patch, rendering it more vulnerable to trauma.

Gastroschisis Complications

·                 Respiratory distress (

·                 Bowel necrosis

·                 Short gut syndrome

·                 Hypothermia, dehydration, sepsis

·                 Necrotizing enterocolitis

Prognosis. Over the past 30 years, the survival rate of babies with gastroschisis and omphalocele has steadily improved, from approximately 60% in the 1960s to more than 90% currently. The observed decline in morbidity and mortality has resulted from improvements in the care of low birth weight and premature babies, particularly those who, because of open abdominal wounds and extruded intestine (gastroschisis).

In children with omphalocele prognosis is dependent upon the severity of the associated problems. Babies with omphalocele are considerably complex, with involvement of many other organ systems. Even giant omphaloceles can be closed, although multiple procedures may be necessary. The limiting factor for many of these babies, however, is their diminutive thoracic cavities and associated pulmonary hypoplasia and resultant chronic respiratory failure. Even so, lung growth and development continue well into childhood, encouraging optimism regarding the ultimate prognosis.

In children with gastroschisis prognosis is dependent mainly upon severity of associated problems, including prematurity, intestinal atresia, short gut, and intestinal inflammatory dysfunction.

 

2. Inguinal hernia

Today, inguinal hernia repair is one of the most common pediatric operations performed. Inguinal hernia is a type of ventral hernia that occurs when an intra-abdominal structure, such as bowel or omentum, protrudes through a defect in the abdominal wall. Most hernias that are present at birth or in childhood are indirect inguinal hernias. Other less common types of ventral hernias include umbilical, epigastric, and incisional hernias.

Fig. A premature baby boy with bilateral giant inguino-scrotal hernias. Because of the large size of the hernias, operative repair sometimes requires repair of the inguinal floor in addition to the high ligation of the indirect hernia sac

 

Indirect hernia. An indirect inguinal hernia follows the tract through the inguinal canal. Differentiating a direct hernia from an indirect hernia requires familiarity with boundaries for this passage. The canal begins in the intraabdominal cavity at the internal inguinal ring (located lateral to the inferior epigastric arteries, approximately midway between the pubic symphysis and anterior iliac spine). The canal courses down along the inguinal ligament. The external ring of the canal is located medial to the inferior epigastric arteries, subcutaneously and slightly above the pubic tubercle. Contents of this hernia then follow the tract of the testicle down into the scrotal sac.

Direct hernia. A direct inguinal hernia usually occurs because of a defect within the boundaries of an area called the Hesselbach triangle. This triangle is defined inferiorly by the inguinal ligament, superolaterally by the inferior epigastric arteries, and medially by the conjoined tendon.

Etiology of the indirect inguinal hernia. The embryology of the groin and of testicular descent largely explains indirect inguinal hernias. An indirect inguinal hernia is a congenital hernia regardless of the patient’s age, and it occurs because of protrusion of an abdominal viscus into the open processus vaginalis. If the processus contains viscera, it is an indirect hernia; if peritoneal fluid fluxes between the space and the peritoneum, it is a communicating hydrocele, a noncommunicating scrotal hydrocele without exchange, or a hydrocele of the cord. In girls, it is a hydrocele of the canal of Nuck.

The inguinal canal forms by mesenchyme condensation condensing around the gubernaculum (Latin for rudder because it guides the testis into the scrotum). During the first trimester, it extends from the testis and to the labioscrotal fold. The processus vaginalis and its fascial coverings also form during the first trimester. A bilateral oblique defect in the abdominal wall develops during the sixth or seventh week of gestation as the muscular wall develops around the gubernaculum. The processus vaginalis protrudes from the peritoneal cavity and lies anteriorly, laterally, and medially to the gubernaculum by 8 weeks’ gestation. The testis produces many male hormones beginning at 8 weeks’ gestation.

At the beginning of the seventh month of gestation, the gubernaculum begins marked swelling influenced by a nonandrogenic hormone, which results in expansion of the inguinal canal and the labioscrotal fold, forming the scrotum. The genitofemoral nerve also influences migration of the testis and gubernaculum into the scrotum under androgenic control.

The female inguinal canal and processus is much less developed than is the male equivalent. In the female embryo, the ovaries descend into the pelvis but do not leave the abdominal cavity. The upper portion of the gubernaculum becomes the ovarian ligament, and the lower portion becomes the round ligament, which travels through the inguinal ring into the labium majus. If the processus vaginalis remains patent, it extends into the labium majus and is known as the canal of Nuck.

Gonads develop on the medial aspect of the mesonephros at 5 weeks’ gestation. The kidney then moves cephalad, leaving the gonad to reside in the pelvis, with a ligamentous attachment to the proximal gubernaculum, until the seventh month of gestation.

The gonads migrate along the processus vaginalis, with the ovary descending into the pelvis and the testis being enwrapped within the distal processus, the tunica vaginalis. The processus in 40-50% of boys fails to close adequately at birth.

When luminal obliteration fails to occur, a ready-made sac is present where abdominal contents may herniate. Even when the processus vaginalis is patent, the entrance may be adequately covered by the internal oblique and transverse abdominal muscles, preventing escape of abdominal contents for many years.

Frequency. Although the exact incidence of indirect inguinal hernia in infants and children is unknown, the reported incidence ranges from 1-5%. Hernias are present on the right side in 60% of patients, on the left in 30%, and bilaterally in 10% of patients. Premature infants are at increased risk for inguinal hernia, with incidence rates of 2% in females and 7-30% in males. Approximately 5% of all males develop a hernia during their lifetime.

Mortality/Morbidity. An incarcerated or strangulated inguinal hernia can result in severe complications and even death.

An incarcerated or strangulated inguinal and/or femoral hernia may result in significant sequela, depending on which visceral structure is involved in the hernia sac. Such sequela can range from life-threatening complications to gonadal dysfunction, including intestinal necrosis and perforation, intestinal obstruction, intestinal stricture, testicular necrosis, testicular atrophy, ovariaecrosis, ovarian atrophy, and tubal stricture.

Sex. Inguinal hernias are much more common in males than in females. The male-to-female ratio is estimated to be 4-8:1.

Age. Premature infants are at an increased risk for inguinal hernia, with the incidence ranging from 7-30%. Moreover, the associated risk of incarceration is more than 60% in this population. Most pediatric ventral and inguinal hernias are detected in the first year of life. Occasionally, hernias may remain asymptomatic and unnoticed by the parents until later in life. Finding an adult patient with an indirect inguinal hernia that has been present since birth is not unusual.

Clinical : History and physical examination axiomatically are the best means of diagnosis of hernias.

History. The infant or child with an inguinal hernia generally presents with an obvious bulge at the internal or external ring or within the scrotum. The parents typically provide the history of a visible swelling or bulge, commonly intermittent, in the inguinoscrotal region in boys and inguinolabial region in girls.

 

The swelling may or may not be associated with any pain or discomfort. More commonly, no pain is associated with a simple inguinal hernia in an infant. The parents may perceive the bulge as being painful when, in truth, it causes no discomfort to the patient.

The bulge commonly occurs after crying or straining and often resolves during the night while the baby is sleeping.

If the patient or the family provides a history of a painful bulge in the inguinal region, one must suspect the presence of an incarcerated inguinal hernia. Patients with an incarcerated hernia generally present with a tender firm mass in the inguinal canal or scrotum. The child may be fussy, unwilling to feed, and crying inconsolably. The skin overlying the bulge may be edematous, erythematous, and discolored.

Physical: Examine the patient in both supine and standing positions. Physical examination of a child with an inguinal hernia typically reveals a palpable smooth mass originating from the external ring lateral to the pubic tubercle. The mass may only be noticeable after coughing and it should be reduced easily. Occasionally, the examining physician may feel the loops of intestine within the hernia sac. In girls, feeling the ovary in the hernia sac is not unusual; it is not infrequently confused with a lymph node in the groin region. In boys, palpation of both testicles is important to rule out an undescended or retractile testicle.

Silk sign. When the hernia sac is palpated over the cord structures, the sensation may be similar to that of rubbing 2 layers of silk together. This finding is known as the silk sign and is highly suggestive of an inguinal hernia. The silk sign is particularly important in young children and infants, in whom palpation of the external inguinal ring and inguinal canal is difficult because the patients’ small size.

Spontaneously reducing hernia. Inguinal hernias that reduce spontaneously, ie, they are only noticed by the parents or caregivers and elude the examining physician, are not unusual. In such cases, maneuvers to increase the patient’s intra-abdominal pressure may be attempted. Lifting the infant’s or the child’s arms above the head may provoke crying or a struggle to get free and thus increased intra-abdominal pressure. Older children can be asked to cough or blow up a balloon.

Inguinal hernia incarceration. The bowel can become swollen, edematous, engorged, and trapped outside of the abdominal cavity, a process known as incarceration. Incarceration is the most common cause of bowel obstruction in infants and children and the second most common cause of intestinal obstruction. If entrapment becomes so severe that the vascular supply is compromised, inguinal hernia strangulation results. In cases of incarceration, ischemic necrosis develops, and intestinal perforation may result, representing a true medical emergency. When an incarceration is encountered, an attempt should be made to reduce it manually if the patient has no signs of systemic toxicity (eg, leukocytosis, severe tachycardia, abdominal distention, bilious vomiting, discoloration of the entrapped viscera). If the patient appears toxic, emergent surgical exploration after appropriate resuscitation is necessary.

Figures regarding inguinal hernia incarceration indicate the following risk patterns:

o        Incarceration occurs in 17% of right-sided hernias and 7% of left-sided hernias.

o        More than 50% of cases of incarceration occur within the first 6 months of life; the risk gradually decreases after 1 year of age.

o        Premature infants have twice the risk of incarceration than the general pediatric population.

o        More than two thirds of all incarcerations occur in children younger than 1 year.

o        Girls are more likely to develop incarceration of an inguinal hernia; the incidence in girls is 17.2%, whereas the incidence in boys is 12%.

Lab Studies. No laboratory studies are needed in the assessment of a patient with a suspected inguinal hernia.

Imaging Studies. Imaging studies are generally not indicated to assess for inguinal hernia. However, ultrasonography can be helpful in the assessment of selected patients. Some advocate the use of ultrasonography to differentiate between a hydrocele and an inguinal hernia. Ultrasonography is capable of finding a fluid-filled sac in the scrotum, which would be compatible with a diagnosis of hydrocele. However, if the patient has an incarcerated inguinal hernia, ultrasonography may not be sensitive enough to differentiate between the two conditions.

Histologic Findings: Hernia sacs are composed of fibrous and connective tissue. Embryonal müllerian remnants are recognized in 1-6% of surgical specimens; therefore, the finding of vas or epididymis on the surgical pathology specimen of a hernia sac does not necessarily imply injury.

Differential diagnosis.

Figure . From left, configurations of hydrocele and hernia in relation to patency of the processus vaginalis.

Hernia and hydrocele. In boys, differentiating between a hernia and a hydrocele is not always easy. Transillumination has been advocated as a means of distinguishing between the presence of a sac filled with fluid in the scrotum (hydrocele) and the presence of bowel in the scrotal sac. However, in cases of inguinal hernia incarceration, transillumination may not be beneficial because any viscera that is distended and fluid-filled in the scrotum of a young infant may also transilluminate. A rectal examination may be helpful if intestine can be felt descending through the internal ring.

Femoral hernia. A femoral hernia can be very difficult to differentiate from an indirect inguinal hernia. Its location is below the inguinal canal, through the femoral canal. The differentiation is often made only at the time of operative repair, once the anatomy and relationship to the inguinal ligament is clearly visualized. The signs and symptoms for femoral hernias are essentially the same as those described for indirect inguinal hernias.

Inguinal lymphadenitis. An enlarged inguinal lymph node can mimic an incarcerated inguinal hernia, and surgical exploration may occasionally be necessary to confirm the diagnosis.

Children commonly have catscratch disease lymphadenitis. Feline contact by a scratch or bite causes Bartonella henselae infection. A papule develops in 3-5 days, followed by regional lymphadenopathy in 1-2 weeks. Attendant symptoms of fever, malaise, myalgia, anorexia, encephalitis, oculoglandular disease, or severe systemic disease complicate 12% of cases. By age 2 months, symptoms usually resolve spontaneously. Infections such as toxoplasmosis, tularemia, infectious mononucleosis, Actinomyces israelii, and human immunodeficiency virus can also cause inguinofemoral adenopathy. Some athletes may have painful reactive inguinal or femoral lymph nodes from repeated trauma.

Treatment.

Inguinal hernias do not heal spontaneously and must be surgically repaired because of the ever-present risk of incarceration. Surgical repair should be performed very soon after the diagnosis is confirmed. Hydrocele without hernia ieonates is the only exception in which surgical treatment may be delayed. Repair of hydroceles ieonates without the presence of hernia is typically delayed for 4-6 months because the connection with the peritoneal cavity (via the processus vaginalis) may be very small and may have already closed or be in the process of closing. Fluid in the hydrocele comes from the peritoneal cavity and is gradually absorbed if the communication has closed. If the hydrocele persists after this observation period, operative repair is indicated and appropriate.

Although adult surgical procedures for correction of inguinal hernias are numerous and varied, only 3 procedures are necessary for the surgical repair of indirect inguinal hernias in children: (1) high ligation and excision of the patent sac with anatomic closure, (2) high ligation of the sac with plication of the floor of the inguinal canal (the transversalis fascia), and (3) high ligation of the sac combined with reconstruction of the floor of the canal.

The first procedure, high ligation and excision of the patent sac with anatomic closure, is the most common operative technique. It is appropriate when the hernia is not very large and has not been present for long. The second procedure, high ligation of the sac with plication of the floor of the inguinal canal (the transversalis fascia), is necessary when the hernia has repeatedly passed through the internal ring and has enlarged the ring, thus partially destroying the inguinal floor. The third procedure, high ligation of the sac combined with reconstruction of the floor of the canal, is occasionally necessary in small children with large hernias or when the hernia is long-standing. The protruding hernia causes gradual enlargement of the ring, progressing to complete breakdown of the transversalis fascia that forms the floor of the inguinal canal. The McVay or Bassini technique of herniorrhaphy is preferred.

Repair of the pediatric inguinal hernia.

Place the patient on the operating table in a supine position with his or her legs slightly abducted. Make an incision in the skin of the inguinal crease just lateral to the pubic tubercle. The skin incision is typically small (1-2 cm).

Next, identify and incise the Scarpa fascia. In young children, the Scarpa fascia may be confused with the aponeurosis of the external oblique.

Begin dissection through the external oblique at the lateral aspect of the incision and extend to the inguinal ligament. Find the external ring by dissecting medially along the inguinal ligament. Incise the ring, taking care to avoid injury to the usually visible ilioinguinal nerve. This incision reveals the cremaster fibers of the cord. Do not lift the cord; use forceps to carefully dissect away the cremasteric fibers.

The hernia sac can be identified in the anteromedial aspect of the cord, and medial retraction of the sac reveals the underlying testicular vessels and vas deferens. Use fine tissue forceps to tease these structures away from the hernia sac. An Allis clamp may be placed around the vas and the testicular vessels to keep them away from further dissection.

The sac can then be clamped and divided. The proximal sac is mobilized to the internal ring, which is often signified by the presence of retroperitoneal fat.

Once the sac is confirmed to be empty, it is twisted on itself and doubly suture-ligated with nonabsorbable sutures (eg, 4-0 or 3-0 silk).

If the ring is not enlarged, open the distal sac to insert a smooth instrument to assist in the return of the cord and testis into the scrotum. Then, close the layers.

If the internal ring is enlarged, the cord must be elevated from its bed with a soft rubber drain. A silk suture between the transversalis fascia and the inguinal ligament can be used to tighten the ring.

If destruction of the canal floor is present, a reconstructive procedure, such as that of Bassini or McVay, may be necessary.

The McVay type of repair incorporates a relaxing incision in the rectus sheath that allows the conjoined tendon to be pulled down to the Cooper ligament and the femoral sheath.

Close the incised aponeurosis of the external abdominal oblique muscle with interrupted 4-0 or 5-0 silk sutures or a continuous 4-0 polyglycolic acid suture.

Use 2 or 3 interrupted 4-0 absorbable sutures to close the Scarpa fascia. Use interrupted subcuticular sutures of 4-0 plain catgut to approximate the skin edges.

Inguinal hernia surgery in girls: In girls, a sliding hernia may contain the ovary or a portion of the fallopian tube. These structures should be carefully dissected from the internal wall of the sac before suture ligation. An alternate procedure involves incising the sac along the ovary and tube on either side and folding the flap into the peritoneum. A pursestring suture can then be used to close the sac. In the female, the sac can be sutured closed after division of the round ligament because no important structures pass through the inguinal ring.

Laparoscopic Repair

As more pediatric surgeons have gained expertise in laparoscopy, the benefits have become widely recognized. Tekehara et al. were the first to describe the laparoscopic needle-assisted repair (LNAR) that we currently use. The cosmetic results are superior to traditional open herniorraphy, recurrence rates are similar, and a lower risk of injury to the spermatic vessel and vas has been reported (Fig. 85.4–85.7).

The procedure is performed under general anesthesia

with muscle relaxation. A gentle Crede maneuver is used to empty the bladder. Access to the peritoneal cavity is accomplished through the umbilicus with a Veress needle. The peritoneal cavity is insufflated with carbon dioxide to a pressure of 6–8 mmHg. A 3- or 5-mm trocar is placed through the infra-umbilical incision and a 2.7- or 5-mm 30° angled laparoscope is utilized. The diagnosis of unilateral or bilateral inguinal hernias is confirmed. A small incision is made on the lateral abdominal wall at the level of the umbilicus (lateral to the rectus muscle), opposite to the side of the hernia, to allow insertion of a 3-mm laparoscopic Maryland forceps under direct visualization. This instrument

is used to move and manipulate the spermatic vessels and vas during placement of the needle for repair of the hernia.

The first step is to clearly visualize the lateral and medial border of the open internal inguinal ring. A 22-gauge Tuhoi spinal needle with a 2-0 polypropylene suture threaded inside the barrel is inserted and passed underneath the peritoneum and the inguinal ligament, lateral to the internal inguinal ring, away from the spermatic vessels and vas. All needle movements are performed by the operating surgeon from outside the body cavity under laparoscopic control so that the position of the tip of the needle can be placed precisely at the desired location inside the peritoneal cavity.

The Maryland dissector is used to move the cord structures and peritoneum during placement of the needle and suture. The second step is to place a suture around the internal inguinal ring: The thread is pushed through the needle into the abdominal cavity creating an internal loop. The needle is pulled out, leaving the polypropylene loop of the thread inside the abdomen. From outside the patient’s body, one of the threaded ends is introduced again into the barrel of the spinal needle and the needle is than passed through the same skin puncture point, through the medial aspect of the internal inguinal ring, under the peritoneum. Again the vas and vessels are mobilized to stay away from the needle in order to prevent injury. Once the tip of the needle is in the desired positioext to the loop of polypropylene (inside the abdomen), the thread is pushed in so that it passes through the loop. At this point the thread-loop is pulled out of the abdomen with the thread end caught by the loop. In this way, the suture thread of polypropylene is placed around the internal inguinal ring under the peritoneum, creating a complete purse-string suture with the ends of the suture coming out of the same skieedle hole in the groin region. The knot is tied to allow for complete closure of the internal inguinal ring and hernia opening. With this technique the knot is buried in the subcutaneous tissue. The small skieedle hole is closed with steri-strips.

Fig. 85.4  Laparoscopic needle-assisted repair of inguinal hernia (LNAR): placement of loop of polypropylene through the lateral aspect of the internal inguinal ring

 

Fig. 85.5 LNAR: placement of the spinal needle and polypropylene suture through the medial aspect of the internal inguinal ring

 

 

Fig. 85.6 LNAR: completion of the loop of polypropylene around the internal inguinal ring

 

 

Fig. 85.7 LNAR: complete closure of the internal ring after tying the knot (extra-corporeal) of the polypropylene suture (buried in the subcutaneous tissue and not visible here)

 

Exploration of the contralateral side.The question of when the contralateral side needs to be explored is much debated. Advantages for exploration of the opposite side during repair of a known inguinal hernia include the following:

§     Existence of a patent processus vaginalis on the contralateral side (also called asymptomatic hernia) in a significant number of patients

§     Avoidance of second surgery and anesthetic if contralateral patent processus vaginalis becomes symptomatic

§     Eliminated cost of second surgery, if needed

Disadvantages include the following:

§     Occasional injury to the vas or testicular vessels during surgical exploration

§     Increased operating time for contralateral procedure

§     May be unnecessary in as many as 70% of all patients undergoing hernia surgery

Available literature indicates that neither age nor sex predicts whether a child has a unilateral or bilateral hernia. No diagnostic test can effectively determine the presence of an asymptomatic inguinal hernia. Physical examination alone cannot detect an unsuspected asymptomatic patent processus vaginalis, particularly in infants and small children, nor is physical examination a consistent predictor of the status of the contralateral region.

Management of incarcerated hernia. When an incarceration is encountered, manual reduction should be attempted if the patient has no signs of systemic toxicity, including leukocytosis, severe tachycardia, abdominal distention, bilious vomiting, and discoloration of the entrapped viscera. If the patient appears toxic, emergent surgical exploration is necessary.

Manual reduction of incarcerated hernia.

Once incarceration of an inguinal hernia has been confidently diagnosed, the parents must be informed that reduction of the hernia will be attempted. The patient is placed in the supine position and his or her pelvis is grasped gently but firmly by an assistant to prevent any lateral movement of the buttocks. Depending on the side of the hernia, the ipsilateral leg is then externally rotated and completely flexed into the frog position. This position causes the external ring to ascend so that it more nearly, but not completely, overrides the internal inguinal ring.

Once both of these conditions have been established, the first 2 fingers of the guiding hand are placed over the hernial bulge and overriding the upper margin of the external inguinal ring in such a fashion as to prevent the hernia subluxating upwards and over the margin of the ring. Next, the apex of the hernia is grasped between the first 2 fingers and thumb of the reducing hand and prolonged, steady, firm pressure is applied.

This last point is crucial; the reducing hand must not be withdrawn after only a few seconds. One indication of the correct application of this technique is the onset of stiffness in the first 2 fingers and an ache in the thenar eminence. After a given interval that may take minutes, a sudden reduction of the hernia occurs with an almost audible thud, accompanied by complete relief in the patient. Using this method of reduction, open operation of incarcerated inguinal hernia is a rare event.

As a rule, forceful manual reduction is recommended in all cases of incarcerated hernia, unless the clinician suspects the possibility of inguinal hernia strangulation. Such attempts are successful in more than 90% of cases and pose minimal risk to the entrapped structure. Successful reduction of an incarcerated inguinal hernia results in immediate patient comfort, relief of obstruction, and prevention of strangulation. Immediate surgery is performed if the reduction is unsuccessful; otherwise, elective operation is scheduled within 24-72 hours after reduction because recurrent incarceration is quite common.

Surgery following inguinal hernia incarceration: In the event of surgery for an incarcerated hernia in which the peritoneal fluid is found to be hemorrhagic or cloudy, material should be sent for culture. Consider enlarging the inguinal incision or creating a counterincision to verify that no nonviable intestine is in the abdomen.

Management of hernia strangulation: Once an incarcerated hernia becomes strangulated, reduction without operative intervention is not possible. Because of significant swelling from the compromised bowel, the presence of intestinal ischemia secondary to incarceration precludes the possibility of reducing the hernia back into the peritoneal cavity. In such cases, immediate operative intervention is indicated, and the viability of the intestine must be carefully assessed at the time of surgery. If necrosis has developed, resect the affected segment of bowel. Incidence of hernia recurrence after emergent surgery for incarceration or strangulation is typically much higher than that reported for elective hernia repair.

Postoperative care.

Diet. No dietary restrictions are indicated in the treatment of children with hernias.

Activity. No specific limitations are indicated once the diagnosis of an inguinal hernia has been established; however, following operative repair, avoidance of major physical activity for 1 week is recommended. After that time, the patient is allowed to participate in physical activities (eg, sports, swimming, running). Children younger than 5 years are likely to recover extremely quickly from surgery; they are typically capable of returning to their normal level of activities within 24-48 hours of surgery.

Further Inpatient Care. Most patients who undergo elective repair of an inguinal or umbilical hernia are discharged from the hospital shortly after surgery. Overnight observation is indicated only in small premature babies who are at risk for postoperative apnea. Such patients are usually admitted for 24-hour observation and monitoring in the hospital.

Further Outpatient Care. Routine follow-up care after operative repair of an inguinal hernia typically requires only one office visit if the parents have reported no problems or complications. Scrotal swelling and bruising after surgery are common and may last for 1-3 weeks. Such signs do not indicate any complications; they represent normal postoperative changes.

Postoperative complications.

Few complications result from operative repair of an inguinal hernia. Possible consequences of hernia repair include decreased testicular size (<20% of patients), testicular atrophy (1-2%), vas injury (<1%), and development of sperm-agglutinating antibodies. The risk of gonadal injury in females is low. Fortunately, in the hands of pediatric surgeons, such complications are quite rare.

The incidence of wound infection is 1-2%.

Hernia recurrence rates are less than 1% when experienced pediatric surgeons perform the operation. Factors associated with recurrence of inguinal hernia include an unrecognized tear in the sac, failure to repair an enlarged inguinal ring, damage to the canal and inguinal floor, infection, history of incarceration, and conditions producing increased intra-abdominal pressure, such as chronic respiratory problems.

The vas deferens and ilioinguinal nerve occasionally may be injured and should be repaired with 7-0 or 8-0 Maxon sutures.

Prognosis. Overall prognosis is excellent; most patients do extremely well after operative repair of their inguinal hernia. Mortality is extremely rare but, unfortunately, continues to be reported as a consequence of delayed recognition of an incarcerated and strangulated inguinal hernia.

 

3. Umbilical hernia

Fig. This 5-year-old child has a large proboscis-like umbilical hernia.

 

Umbilical hernia is a common disorder in children that pediatric and general surgeons are frequently asked to evaluate and treat. Although the hernia defect is present at birth, unlike other hernias of childhood an umbilical hernia may resolve without the need for an operation. However, these hernias do not always resolve, and complications can develop that require an emergency operation. An understanding of the embryology, anatomy, incidence, natural history, and complications is important to any surgeon managing umbilical hernias in children.

Embryology

The 5-week embryo has a body stalk and yolk sac that enter the ventral aspect of the developing abdominal wall at the site of the umbilical cord. The omphalomesenteric duct forms from the yolk sac, whereas mesenchyme from the stalk forms the umbilical vessels. These structures enter the abdomen through the umbilical ring. The umbilical cord usually consists of two arteries, one vein, the omphalomesenteric duct and urachal remnants, and connective tissue.

After birth, closure of the umbilical ring is the result of complex interactions of lateral body wall folding in a medial direction, fusion of the rectus abdominis muscles into the linea alba, and umbilical orifice contraction aided by elastic fibers from the obliterated umbilical arteries. Fibrous proliferation of surrounding lateral connective tissue plates and mechanical stress from rectus muscle tension may also aid in closure.

Anatomy

Although “direct” and “indirect” umbilical hernias have been described, suggesting the existence of congenital and acquired lesions, virtually all pediatric umbilical hernias are congenital and form as a hernia through a persistent umbilical ring. The hernia sac is peritoneum, which is frequently adherent to the dermis of the umbilical skin. The actual fascial defect can range from several millimeters to 5 cm or more in diameter. The extent of the skin protrusion is not indicative of the size of the fascia defect. Frequently, small defects can result in alarmingly large “proboscis”-like protrusions (Fig. 49-1). Thus, it is important to palpate the actual fascia defect by reducing the hernia manually to assess whether operative or nonoperative treatment is appropriate.

Incidence

The incidence of umbilical hernia in the general population varies with age, race, gestational age, and coexisting disorders. In the United States, the incidence in African-American children from birth to 1 year old ranges from 25% to 58%, whereas white children in the same age group have an incidence of 2% to 18.5%.1,2 Premature and low birth weight infants have a higher incidence than full-term infants, reported to be up to 75% in infants weighing 500 to 1500 g at birth.3 Infants with certain other conditions, such as Beckwith-Wiedemann syndrome, Hurler’s syndrome, various trisomy conditions (trisomy 13, 18, and 21), and congenital hypothyroidism, also have an increased incidence of umbilical hernia, as do children requiring peritoneal dialysis.4,5

Treatment

It has been known for many years that umbilical hernias will close spontaneously, and it seems very safe to simply observe the hernia until age 3 to 4 years to allow closure to occur. Pressure dressings and other devices to keep the hernia reduced do not speed the resolution and may result in skin irritation and breakdown and are therefore not advisable. Prospective studies in both white and African-American populations have shown spontaneous resolution rates of 83% to 95% by 6 years of age.6-10 Another study has shown 50% of hernias still present at age 4 to 5 years will close by age 11 years.9  One study suggests that hernias with fascial defects greater than 1.5 cm are unlikely to close by age 6 years, whereas other series suggest that even large defects will spontaneously resolve without operation.8,11,12

The primary danger associated with observation therapy is the possibility of incarceration or strangulation. Studies have shown these complications to be quite rare, with an incidence of less than 0.2%.8,12,13 Patients with small fascial defects (0.5 to 1.5 cm in diameter) appear more prone to incarceration.14 Strangulation with or without bowel infarction is even more rare. In general, informing the adult caregivers in the family regarding the signs and symptoms of incarceration, along with periodic follow-up, should ensure a safe observation period while waiting for spontaneous closure.

The operative closure of an umbilical hernia uses standard techniques, is generally straightforward, and can usually be completed as an outpatient procedure. Although a “minimally invasive” technique has been described using injection of a sclerosing agent,15 most of these abnormalities are repaired using more traditional suture closure of the defect. Methods used commonly in the adult, such as prosthetic placement, are almost never needed in the child.

The most common method of repair is shown in Figures 49-2 and 49-3. A small transverse infraumbilical incision is made, usually placed in the redundant skin, which is inverted at the conclusion of the procedure, thereby burying the closed incision. The hernia sac is identified and dissected free from the dermis, underlying the umbilical cicatrix. Our technique includes excision of the sac to the fascial edges, although other authors have described a more limited excision or simple inversion of the sac through the fascial opening. Interrupted sutures of nonabsorbable or long-lasting absorbable sutures are placed and tied, closing the fascial defect in a transverse fashion. We leave the needle attached to the center fascia suture, which is then used to tack the underside of the umbilical cicatrix to the fascia. The skin incision is closed with an absorbable subcuticular suture, and a dressing is applied. Pressure dressings are generally unnecessary.16

Excision of the redundant skin is usually not performed because it tends to return to normal appearance after the hernia is repaired. This can take up to 12 months to occur, and the family should be reassured appropriately. If the umbilicus fails to return to an acceptable appearance after 1 to 2 years, there are a number of techniques described to restore it to a more normal configuration.17-19

The complications of umbilical hernia repair are few and include seroma or hematoma formation, which are usually self-limited and resolve spontaneously. Wound infections can generally be treated with local care and antibiotics, whereas a recurrent hernia, occurring in less than 1%, is treated with reoperation.14

Surgical care.

Umbilical hernia repair is carried out under general anaesthesia. A semicircular incision is made in the skin crease immediately below the umbilicus. The subcutaneous layers are dissected in order to expose the hernial sac. By blunt dissection with a mosquito clamp, a plane is developed on both sides of the sac and the sac is encircled with a haemostat and is divided.

A clamp is placed on either side of the umbilical defect for traction. The defect is closed by interrupted 2/0 absorbable sutures. A stitch is used to invaginate the umbilical scar, tractioning it downwards and fixing it to the subcutaneous layer in the midline. The wound is closed with several interrupted sutures placed in the subcuticular plane. A slightly compressive dressing is maintained for 24 h.

 

Figure. Diagram of technique for operative repair for umbilicalhernia. A, An infraumbilical skin crease incision is made.B, The hernia sac is opened, leaving a portion of the sac attached to the umbilical skin for ease of subsequent umbilicoplasty. C, The umbilical sac has been completely divided and excised to strong fascia. D, The fascial defect is closed in a transverse fashion with interrupted, simple nonabsorbable sutures. E, The remaining umbilical sac, which is attached to the umbilical skin, is secured to the fascia with interrupted, absorbable sutures. F, The skin incision is closed with a subcuticular suture.

 

Figure . The steps depicted in the operative diagram are shown. A, An infraumbilical incision is made. B, The umbilical hernia sac has been encircled with a hemostat. C, The umbilical hernia sac is excised, and transverse closure of the fascial defect is accomplished with interrupted long-lasting absorbable sutures. D, The umbilicus has been tacked to the fascial closure, and the skin is approximated with a subcuticular closure.

 

4. Cryptorchidism

Cryptorchidism is defined as failure of the testis to descend from its intra-abdominal location into the scrotum. The exact etiology of cryptorchidism is not known. In one third of patients, the condition is bilateral. Ultrasound (US), CT, MRI, arteriography, and laparoscopy are used for diagnosis.

Orchiopexy is the treatment of choice and usually is performed in patients aged 8 – 24 months. Cryptorchid testis is 20-48 times more likely to undergo malignant degeneration thaormal testis. Orchiopexy does not alter the risk of malignant transformation. The incidence of malignant transformation also is increased in the unaffected testis. Consider hormone treatment with either human chorionic gonadotropin or gonadotropin-releasing hormone analogues for palpable high-scrotal position of the testis; however, efficacy is less than 20%. Surgical treatment is most effective and reliable.

Pathophysiology. A normal testis develops in the celomic cavity and begins to descend into the scrotum at 36 weeks, guided by the contractile cordlike structure termed the gubernaculum testis. The distal bulbous portion of the gubernaculum testis is termed the pars infravaginalis gubernaculi. After complete descent into the scrotum, the gubernaculum testis atrophies; however, it persists if the descent is not complete.

The processus vaginalis represents a peritoneal diverticulum in the embryonic lower anterior abdominal wall that transverses the inguinal canal during the 7th month of gestation carrying with it the testis which descends through the inguinal canal and into the scrotum.

Therefore, 100% of infants <900 grams will have undescended testes while 17% of infants between 2000-2500 grams will be affected and 3.4% of full term infants.

Undescended testis is not associated with urinary tract anomalies.

Anorchia (absence of functioning testes) is present in 3-4% of undescended testes and 20% of nonpalpable testes

Anatomy. Testicular size depends on age and stage of sexual development. Before age 12 years, testicular volume is 1-2 cm³. Mean testicular volume at age 16 years is 14 cm³.

US is the most frequently used imaging study for the testicle. On US, prepubertal testes are of low-to-medium level echogenicity. A normal adult testis has medium level echoes and measures 5 × 3 × 2 cm. The tunica albuginea is the fibrous covering of the testicle. Septa extend from the tunica albuginea into the testicle, dividing the testes into lobules. The posterior surface of the tunica albuginea is reflected into the interior of the gland, forming the incomplete septum termed the mediastinum of the testis.

Sonographically, this is seen as an echogenic band running across the testis. Each lobule is composed of many seminiferous tubules that open via tubules (tubuli recti) into dilated spaces termed the rete testes within the mediastinum. These in turn communicate via efferent ductules in the epididymal head. The epididymis is composed of a head, body, and tail, the ducts of which continue as the vas deferens in the spermatic cord.

Risk Factors and Causes

The cause of undescended testicle is unknown. Having a father or brother who had the condition increases the risk. Other risk factors include the following:

·          Low birth weight (less than 2500 g)

·          Maternal exposure to estrogen during the first trimester

·          Multiple birth (e.g., twin, triplet)

·          Premature birth (before 37 weeks gestation)

·          Small size for gestational age

Types of Cryptorchidism

1. True Undescended Testes:

§   the testes are found within the normal path of descent with a patent processus vaginalis

§   testis may be found intra-abdominally or intracanicular (within the inguinal canal)

2. Maldescended Testes

§     testes have descended through the inguinal canal but are positioned in the subcutaneous tissue outside the scrotum

The most common location of cryptorchid testis is the inguinal canal (72%), followed by prescrotal (20%) and abdominal (8%) locations.

Frequency. Incidence of cryptorchidism 7/1000 at 1 year of age

Mortality/Morbidity. The lifetime risk of death from testicular malignancy in men of any age with undescended testis is approximately 9.7 times the risk in men with normally descended testis.

Infertility. This condition is observed in 40% of patients with unilateral and 70% of patients with bilateral cryptorchidism.

Malignant degeneration. Testicular malignancies occur in 10% of men with cryptorchid testis. The incidence of malignant degeneration in an undescended testis is reportedly as high as 48 times greater than in the normal testis. Seminoma is the most commonly reported malignancy.

Torsion. This rare condition, if present, usually is secondary to the presence of a mass.

Age. Cryptorchidism usually presents at birth or by preadolescence; however, it can present at any age. Avoid intervention before age 1 year because of the possibility of spontaneous descent.

Clinical Details. Patients present with the condition or the parents bring the child with nonpalpable testis.

Physical examination reveals a nonpalpable testis in the scrotum. The most common location of the cryptorchid testis is in the inguinal canal (72%), followed by prescrotal (20%) and abdominal (8%) locations.

 

The primary treatment of cryptorchid testis is orchiopexy.

Preferred Examination

Imaging studies, diagnostic procedures

Pelvic Ultrasound is the first imaging modality performed on a cryptorchid testis for the following reasons:

ü    Of cryptorchid testes, 72% are in the inguinal canal; therefore, they are easily accessible to US examination.

ü    US is readily available.

ü    US is easy to schedule.

If US cannot identify the testis (US effectively detects cryptorchid testis below the level of the internal inguinal ring), MRI and CT are the subsequent modalities of choice. Both can detect an abdominal testis.

Laparoscopy is performed if MRI and CT cannot localize the testis.

Endocrine

Human Chorionic Gonadotropin (hCG) stimulation used to confirm the absence or presence of testicular tissue in patients with bilateral nonpalpable testes – an increase in testosterone levels after hCG stimulation indicates functioning testicular tissue

Gonadotrophins. High FSH and LH indicate a congenitally anorchid patient as there is a lack of negative feedback by testesterone – low or normal FSH and LH levels may indicate functioning gonadal tissue

Limitations of Techniques:

§    US cannot detect an intra-abdominal testis.

§    CT uses radiation and does not have multiplanar capability.

§    MRI has better soft-tissue contrast and multiplanar capability; however, when the testis is higher in the abdomen, the presence of bowel loops lowers the sensitivity for detecting the cryptorchid testis.

§    Laparoscopy is invasive and expensive.

Differential diagnosis

Testicular ectopia (normal descent but abnormal location, such as perineum, femoral, supra-pubic regions; ionpalpable testis in the scrotum search these areas to exclude ectopia, which is rare in the contralateral hemiscrotum)

 

Retractile testis (often bilateral, normal condition; commonly seen in prepubertal boys; absent in adults)

Congenital absence (anorchia); rare, 4% of patients who clinically have an undescended testis, actually have unilateral absence.

Atrophic testis (usually secondary to torsion; no color flow Doppler or contrast enhancement seen)

Lymph node (fatty hilum, characteristic location adjacent to vessels helps identification)

Pars infravaginalis gubernaculi occasionally mistaken for testis.

Hypospadias and inguinal hernia (associated conditions) – US is easy to schedule.

Treatment

Medical management

Human Chorionic Gonadotropin (hCG ) is used to induce testicular descent; best response in those with bilateral cryptorchidism with the testes near the scrotum (not recommended for unilateral cryptorchidism). Success rate of medical managemen is <10%

Surgery

Surgical exploration (orchipexy) is not indicated in congenitally anorchic patients where the basal FSH and LH levels are elevated and there is a lack of rise of testosterone with hCG stimulation

Orchiopexy indications:

ü    unilateral and bilateral cryptorchidism where the testes are palpable

ü    when the testis is not palpable but located intra-abdominally immediately inside the internal inguinal ring

Orchiopexy is best performed towards the end of the first year of life or early in the 2nd year of life, because irreversible degenerative changes may occur without correction by two years of age.

If the testicle is located outside of the abdomen (i.e., in the groin), the procedure is performed under general anesthesia and the patient is usually discharged the next day.

In this procedure, the testicle is located, removed through a small incision, and placed into the scrotum through another small incision. The testicle may be sutured into place.

 

Strenuous activity should be avoided for approximately 1 month. Success rates for this procedure are generally good.

Complications. Complications from orchidopexy include adverse reactions to anesthesia, bleeding, and infection.

Prognosis. Undescended testicles usually descend into the scrotum without intervention within the first year of life. The prognosis for fertility in these cases, as well as those that are surgically corrected, is good.

Orchiopexy does not eliminate the risk of future malignancy.