HERNIAS, THORACIC CONDITIONS AND ABDOMINAL WALL DEFECTS

HERNIAS, THORACIC CONDITIONS AND ABDOMINAL WALL DEFECTS

A. Diaphragmatic Hernia

1- Congenital Diaphragmatic Hernia (Bochdalek)

The most common congenital diaphragmatic hernia (CDH) is that which occurs through the postero-lateral defect of Bochdalek. It is caused by failure of the pleuroperitoneal membrane to develop adequately and close before the intestines returning to the abdomen at the tenth week of gestation. The intestines then enter the pleural cavity and cause poor lung development leading to pulmonary hypoplasia (a reduced number of alveoli per area of lung tissue). This defect is postero-lateral in the diaphragm and may vary in size. Stomach, liver or spleen may be partly in chest as well. Frequency is 1:2000 live births and the natural history in prenatally diagnosed CDH is that 60% will die. The clinical presentation is that the newborn becomes rapidly cyanotic, acidotic, and has poor ventilation. Major findings relate to the degree of pulmonary maldevelopment. Chest films will show intestines in the chest. Left sided hernias are more common than right (90% on left). Placement of a radiopaque nasogastric tube may show the tube coiled in the lower left chest. Higher risk factors are: early appearance of symptoms in life, prematurity and associated anomalies. Treatment consists of rapid intubation and ventilation with use of muscle relaxants, placement of a nasogastric tube to prevent gaseous distension of the intestines and preoperative stabilization of arterial blood gases and acid-base status. Surgery can be undertaken when one of the following objectives are met: (1) blood gases normalize with no significant changes between preductal and postductal samples, (2) echocardiogram demonstrate reduce pulmonary pressure and pulmonary peripheral resistance.

Operative management consists of abdominal approach, closure of hernia by primary repair or use of mesh, and correction of malrotation. Postoperative management is very difficult. Due to hypoplastic lungs, there is frequently pulmonary hypertension leading to right-to-left shunting and progressive hypoxemia, hypercarbia, and acidosis that worsens the pulmonary hypertension. The use of chest tubes may cause overstretching of the already hypoplastic alveoli causing: increase pulmonary hypertension, reduce functional residual capacity and reduce lung compliance. Postoperatively, the infant should be kept paralyzed and ventilated and only very slowly weaned from the ventilator. The severity of pulmonary hypoplasia, both ipsilaterally and contralaterally, is the main determinant of outcome. ECMO (extracorporeal membrane oxygenator) has come to reduce somewhat the mortality of this condition.

The mortality of CDH is directly related to the degree of lung hypoplasia associated. Death is caused by persistent pulmonary hypertension and right ventricular failure. Prospective studies of prenatally diagnosed fetus prior to 25 wk. gestation have shown that 60% will die despite optimal postnatal care. This unsolved problem has prompted investigators to develop new treatment options such as preoperative stabilization, jet-frequency ventilation, and ECMO. Another area of development is intrauterine fetal surgical repair. To achieve success fetal surgery should: (1) pose no risk to the mother (innocent bystander) or her future reproductive capacity; (2) tocolytic therapy in the post-op weeks should proved effective to avoid prenatal stillbirths; and (3) the procedure should be superior to conventional therapy. Intrauterine repair has meet with limited success due to herniation of the fetal liver into the chest through the defect. Disturbance of the umbilical circulation during or after liver reduction causes fetal death. Positive-pressure ventilation after birth reduces the liver before the baby comes for surgical repair. Dr. Harrison (USFC Fetal Treatment Center) has devised separate fetal thoraco-abdominal incisions to deal with this problem ('two-step dance'), reducing or amputating the left lateral segment of the liver. Another less invasive approach is enlarging the hypoplastic lungs by reducing the normal egress of fetal lung fluid with controlled tracheal obstruction called PLUGS (Plug Lung Until it Grows).

Delayed presentation beyond the neonatal period is rare, estimated to occur in 4‑6% of cases. Infants and children will present with either respiratory or gastrointestinal symptoms such as: chronic respiratory tract infection, vomiting, intermittent intestinal obstruction, and feeding difficulty. Occasionally the child is asymptomatic. The small size of the defect protected by either the spleen or the liver and the presence of a hernial sac may delay the intestinal herniation into the chest. A rise intraabdominal pressure by coughing or vomiting transmitted to any defect of the diaphragm makes visceral herniation more likely. Diagnosis is confirmed by chest or gastrointestinal contrast imaging. Management consists of immediate surgery after preop stabilization. Most defects can be closed primarily through an abdominal approach. Chest‑tube placement in the non‑hypoplastic lung is of help. Surgical results are generally excellent. A few deaths have resulted from cardiovascular and respiratory compromise due to visceral herniation causing mediastinal and pulmonary compression.

2. Morgagni Hernias

Morgagni Hernias (MH) are rare congenital diaphragmatic defects close to the anterior midline between the costal and sternal origin of the diaphragm. They occur retrosternally in the midline or more commonly on either side (parasternally) of the junction of the embryologic septum transversum and thoracic wall (see the figure) representing less than 2% of all diaphragmatic defects. Almost always asymptomatic, typically present in older children or adults with minimal gastrointestinal symptoms or as incidental finding during routine chest radiography (mass or air‑fluid levels). Infants may develop respiratory symptoms (tachypnea, dyspnea and cyanosis) with distress. Cardiac tamponade due to protrusion into the pericardial cavity has been reported. The MH defect contains a sac with liver, small/ large bowel as content. Associated conditions are: heart defects, trisomy 21, omphalocele, and Cantrell pentalogy. US and CT‑Scan can demonstrate the defect. Management is operative. Trans‑abdominal subcostal approach is preferred with reduction of the defect and suturing of the diaphragm to undersurface of sternum and posterior rectus sheath. Large defects with phrenic nerve displacement may need a thoracic approach. Results after surgery rely on associated conditions.

3. Hiatal Hernia

Hiatal hernia is rarely a problem in infants unless associated with gastroesophageal reflux or severe anatomic dysfunction of the stomach (upside-down intrathoracic stomach).

Two types of esophageal hernia recognized are the hiatal and paraesophageal hernia. Diagnosis is made radiologically always and in a number of patients endoscopically. The hiatal hernia (HH) refers to herniation of the stomach to the chest through the esophageal hiatus. The lower esophageal sphincter also moves. It can consist of a small transitory epiphrenic loculation (minor) up to an upside-down intrathoracic stomach (major). HH generally develops due to a congenital, traumatic or iatrogenic factor. Most disappear by the age of two years, but all forms of HH can lead to peptic esophagitis from Gastroesophageal reflux. Repair of HH is determined by the pathology of its associated reflux (causing failure to thrive, esophagitis, stricture, respiratory symptoms) or the presence of the stomach in the thoracic cavity. In the paraesophageal hernia (PH) variety the stomach migrates to the chest and the lower esophageal sphincter stays in its normal anatomic position. PH is a frequent problem after antireflux operations in patients without posterior crural repair. Small PH can be observed. With an increase in size or appearance of symptoms (reflux, gastric obstruction, bleeding, infarction or perforation) the PH should be repaired. The incidence of PH has increased with the advent of the laparoscopic fundoplication.

4. Paraesophageal Hernias

Paraesophageal hernia (PEH), a rare entity in children, occurs when the stomach protrudes laterally through the esophageal hiatus toward the chest while the gastro-esophageal junction stays in anatomic position. Though most cases remain asymptomatic, PEH can cause upper bowel obstruction, gastroesophageal reflux, gastric volvulus, bleeding and perforation. Most PEH in children are acquired resulting after fundoplication. A small group of children are born with the PEH. Groups of patients with a higher incidence of developing PEH after fundoplication includes infants under the age of one, neurologic impaired children and surgical patients where a crural repair is not done after fundoplication. PEH is linked to gagging before an antireflux procedure in children. Diagnosis of PEH is confirmed during a barium swallow and upper gastrointestinal series. A small PEH can be managed non-operatively if the child is asymptomatic. With the presence of symptoms or enlargement of the hernia operative repair must be done. A transabdominal approach is preferred for reducing the stomach and crural repair of the diaphragm. The use of mesh hiatal reinforcement is recommended for patients undergoing reoperation for PEH and recurrent gastroesophageal reflux or if the diaphragmatic crura is thought to require reinforcement at the time of the original surgery.

5. Traumatic Diaphragmatic Hernia

Motor vehicle trauma is the leading cause of an acquired diaphragmatic hernia in a child and adult. The traumatic event can either be penetrating directly injuring the diaphragm, or most commonly blunt abdominal causing a sharp increase in intraabdominal pressure with rupture of the diaphragmatic muscle. The more medial and lateral fibers of the posterior diaphragm arising from the lumbocostal arch and the vertebrocostal trigone are the weakest points of rupture. The posterolateral portion is virtually always the area that ruptures with trauma. Diaphragmatic injuries are difficult to diagnose preoperatively and can be missed easily. Traumatic diaphragmatic hernia should be suspected on the basis of an abnormal chest radiograph in the trauma victim with multiple injuries. If diaphragmatic injury is suspected, ultrasound or CT Scan investigation must be performed. Most cases involve the left diaphragm due to the buttressing effect of the liver. The incidence of bowel strangulation is high in traumatic diaphragmatic hernias. In the acute setting, transabdominal repair after palpation of both hemidiaphragms is the procedure of choice because of the high incidence of associated trauma. Injury severity score and hemorrhagic shock upon admission strongly influence the outcome. Delayed presentation can be repaired through the chest.

B. Lung Bud Anomalies

1. Congenital Lobar Emphysema

Congenital lobar emphysema (CLE) is an unusual lung bud anomaly characterized by massive air trapping in the lung parenchyma that nearly always occurs in infancy and affects males more commonly (2:1). Lobar over distension causes compression of adjacent lung tissue, mediastinal shift and decrease in venous return. When this occurs persistent progressive respiratory distress (dyspnea, tachypnea, wheezing, cough and cyanosis) develops requiring lobectomy. Asymptomatic CLE exists, more commonly beyond infancy and associated with an acute viral respiratory infection. Lobar hyperinflation, flat diaphragms and retrosternal air, mediastinal shift in simple films suggests the diagnosis. CT scan depicts the abnormal anatomy (lung herniation) and the morphology of the remaining lung. V/Q scans confirm the non‑functioning nature of the affected lobe. Upper and middle right lobes are more commonly affected. Etiology centers in a combination of bronchial (flap/valve) obstruction with congenital cartilage dysplasia. Most common associated defect is cardiovascular (VSD, PDA). Symptomatic patients nearly always require lobectomy. Asymptomatic children do not benefit from surgical treatment but need close follow-up. Prenatally diagnosed cases need referral to surgery centers.

2. Pulmonary Sequestration

Pulmonary sequestrations refer to masses of abnormal lung parenchyma with anomalous systemic blood supply not communicating with the normal tracheobronchial tree. The abnormal lung parenchyma may be Intralobar (IS) or Extralobar Sequestration (ES). Intralobar is contained within the visceral pleural of a lower lobe receiving the blood supply from the abdominal aorta or other thoracic vessel. It is believed IS are acquired postinfectious process due to their association with chronic recurrent lung infection and reactive airway disease. ES is a congenital malformation with variable ectopic blood supply (aorta) having its own pleural investment separate from normal lung, containing typical features of CCAM‑2 (40%) and associated malformations (40%). Both types can have patent communication with foregut. Prenatal diagnosis can be obtained with real‑time US with Doppler imaging (can cause fetal lung compression, mediastinal shifts and hydrops). Postnatally, contrast‑enhanced CT may establish the diagnosis eliminating the need for more invasive imaging (arteriography). Most presents in early infancy with a soft tissue opacity in the posterior basal segments of the lung on simple chest films. Management consists of resection to alleviate symptoms and avoid complications. ES can be managed with resection alone, while IS needs lobectomy. Anecdotal cases of partial or total disappearance of these masses while asymptomatic have been reported.

3. Cystic Adenomatoid Malformation

Congenital cystic adenomatoid malformation is a lung bud lesion characterize by dysplasia of respiratory epithelium caused by overgrowth of distal bronchiolar tissue. Prenatally diagnosed CCAM prognosis depends on the size of the lung lesion and can cause: mediastinal shift, hypoplasia of normal lung tissue, polyhydramnios, and fetal hydrops (cardiovascular shunt). Classified in two types based on ultrasound findings: macrocystic (lobar, > 5 mm cysts, anechoic, favorable prognosis) and microcystic (diffuse, more solid, echogenic, lethal). Occurs as an isolated (sporadic) event with a low rate of recurrence. Survival depends on histology. Hydrops is caused by vena caval obstruction, heart compression and mediastinal shift. The natural history is that some will decrease in size, while others disappear. Should be follow with serial sonograms. Prenatal management for impending fetal hydrops has consisted of thoraco-amniotic shunts (dislodge, migrate and occlude), and intra-uterine fetal resection (technically feasible, reverses hydrops, allows lung growth). Post-natal management consist of lobectomy.

4. Bronchogenic Cyst

Bronchogenic cysts (BC), first described in 1911, are benign congenital lesions of the respiratory tract that have the potential to develop complications creating a dilemma in diagnosis and treatment. BC are commonly located in the mediastinum (2/3) or lung parenchyma (1/3) arising from anomalous budding along the primitive tracheobronchial tube (foregut duplication errors). Other atypical locations are cervical, subcutaneous, paravertebral, etc. Contain mucoid material lined with ciliated columnar epithelium (bronchial glands, smooth muscle, cartilage) not communicating with the respiratory tract. Clinical presentation may range from prenatal diagnosis, asymptomatic (1/3) lesions identified during routine work‑up to symptomatic (2/3) cases. Infants may show respiratory distress: cough, dyspnea, cyanosis, hemoptysis or dysphagia. Older children present with chest pain, non‑productive cough or pulmonary infection. Diagnosis relies on chest films and CT‑Scan. Bronchoscopy and barium swallow are not very useful. Infection, hemorrhage, erosion, malignant potential and expansion mandate surgical management consisting of thoracotomy with excision of the lesion if mediastinal in location, and segmentectomy or lobectomy for intraparenchymal cysts. Marsupialization is associated with recurrence.

C. Inguinal hernias, Hydroceles, Undescended & Ectopic Testis

A hernia is defined as a protrusion of a portion of an organ or tissue through an abnormal opening. For groin (inguinal or femoral) hernias, this protrusion is into a hernial sac. Whether or not the mere presence of a hernial sac (or processus vaginalis) constitutes a hernia is debated. Inguinal hernias in children are almost exclusively indirect type. Those rare instances of direct inguinal hernia are caused by previous surgery and floor disruption. An indirect inguinal hernia protrudes through the internal inguinal ring, within the cremaster fascia, extending down the spermatic cord for varying distances. The direct hernia protrudes through the posterior wall of the inguinal canal, i.e., medial to deep inferior epigastric vessels, destroying or stretching the transversalis fascia. The embryology of indirect inguinal hernia is as follows: the duct descending to the testicle is a small offshoot of the great peritoneal sac in the lower abdomen. During the third month of gestation, the processus vaginalis extends down toward the scrotum and follows the chorda gubernaculum that extends from the testicle or the retroperitoneum to the scrotum. During the seventh month, the testicle descends into the scrotum, where the processus vaginalis forms a covering for the testicle and the serous sac in which it resides. At about the time of birth, the portion of the processus vaginalis between the testicle and the abdominal cavity

obliterates, leaving a peritoneal cavity separate from the tunica vaginalis that surrounds the testicle.

Approximately 1-3% of children have a hernia. For infants born prematurely, the incidence varies from 3-5%. The typical patient with an inguinal hernia has an intermittent lump or bulge in the groin, scrotum, or labia noted at times of increased intra-abdominal pressure. A communicating hydrocele is always associated with a hernia. This hydrocele fluctuates in size and is usually larger in ambulatory patients at the end of the day. If a loop of bowel becomes entrapped (incarcerated) in a hernia, the patient develops pain followed by signs of intestinal obstruction. If not reduced, compromised blood supply (strangulation) leads to perforation and peritonitis. Most incarcerated hernias in children can be reduced.

The incidence of inguinal hernia (IH) in premature babies (9-11%) is higher than full-term (3-5%), with a dramatic risk of incarceration (30%). Associated to these episodes of incarceration are chances of: gonadal infarction (the undescended testes complicated by a hernia are more vulnerable to vascular compromise and atrophy), bowel obstruction and strangulation. Symptomatic hernia can complicate the clinical course of babies at NICU ill with hyaline membrane, sepsis, NEC and other conditions needing ventilatory support. Repair should be undertaken before hospital discharge to avoid complications. Prematures have: poorly developed respiratory control center, collapsible rib cage, deficient fatigue-resistant muscular fibers in the diaphragm that predispose then to potential life-threatening post-op respiratory complications such as: need of assisted ventilation (most common), apnea and bradycardia, emesis, cyanosis and re-intubation (due to laryngospasm). Independent risk factors associated to this complications are (1) history of RDS/bronchopulmonary dysplasia, (2) history of patent ductus arteriosus, (3) low absolute weight (< 1.5 Kg), and (4) anemia (Hgb < 10 gm- is associated to a higher incidence of post-op apnea). Postconceptual age (sum of intra- and extrauterine life) has been cited as the factor having greatest impact on post-op complications. These observations makes imperative that preemies (with post conceptual age of less than 45 weeks) be carefully monitored in-hospital for at least 24 hours after surgical repair of their hernias. Outpatient repair is safer for those premature above the 60 wk. of postconceptual age. The very low birth weight infant with symptomatic hernia can benefit from epidural anesthesia.

At times, the indirect inguinal hernia will extend into the scrotum and can be reduced by external, gentle pressure. Occasionally, the hernia will present as a bulge in the soft tissue overlying the internal ring. It is sometimes difficult to demonstrate and the physician must rely on the patient's history of an intermittent bulge in the groin seen with crying, coughing or straining.

Elective herniorrhaphy at a near convenient time is treatment of choice. Since risk of incarceration is high in children, repair should be undertaken shortly after diagnosis. Simple high ligation of the sac is all that is required. Pediatric patients are allowed to return to full activity immediately after hernia repair. Patients presenting with incarceration should have an attempt at reduction (possible in greater than 98% with experience), and then admission for repair during that hospitalization. Bilateral exploration is done routinely by most experienced pediatric surgeons. Recently the use of groin laparoscopy through the hernial sac permits visualization of the contralateral side.

Approximately 1% of females with inguinal hernias will have the testicular feminization syndrome. Testicular feminization syndrome (TFS) is a genetic form of male pseudohermaphroditism (patient who is genetically 46 XY but has deficient masculinization of external genitalia) caused by complete or partial resistance of end organs to the peripheral effects of androgens. This androgenic insensitivity is caused by a mutation of the gene for androgenic receptor inherited as an X-linked recessive trait. In the complete form the external genitalia appear to be female with a rudimentary vagina, absent uterus and ovaries. The infant may present with inguinal hernias that at surgery may contain testes. Axillary/pubic hair is sparse and primary amenorrhea is present. The incomplete form may represent undervirilized infertile men. Evaluation should include: karyotype, hormonal assays, pelvic ultrasound, urethrovaginogram, gonadal biopsy and labial skin bx for androgen receptor assay. These patients will never menstruate or bear children. Malignant degeneration (germ cell tumors) of the gonads is increased (22-33%). Early gonadectomy is advised to: decrease the possible development of malignancy, avoid the latter psychological trauma to the older child, and eliminate risk of losing the pt during follow-up. Vaginal reconstruction is planned when the patient wishes to be sexually active. These children develop into very normal appearing females that are sterile since no female organs are present.

Inguinal hernias are the most common surgical pathology seen in infants and children. A lump in the inguinal canal area of a newborn or infant female is most probably an ovarian incarcerated inguinal hernia. On very rare occasion the lump is a testis in a child with testicular feminization syndrome. Clinically  the irreducible ovarian lump is usually asymptomatic, movable and non-tender mass within the labia majora. Ultrasound can determine the nature of the gonad present. The main problem with an ovarian hernia in infants is the incidence of ovarian torsion associated before repair. Ovaries trapped within inguinal hernias undergo torsion far more commonly than ovaries and tubes in the normal pelvic position increasing the chances of infarction. Torsion can occur at any time after diagnosis of the hernia. The incarcerated ovarian pedicle is narrowed and lengthened within the defect and the internal ring serves as a fixed point around which a twist can occur. The risk of torsion and infarction creates the view that ovarian hernias should be repaired at the earliest elective opportunity if they can be reduced manually. Children with edema, tenderness or skin discoloration in the inguinal area should be repaired immediately. Early recognition and management of this condition reduce the risk of gonadal infarction. During repair surgeons must be aware that in 20% of girls with inguinal hernia, the fallopian tubes occasionally with the ovary or uterus comprise   the wall of the hernial sac (sliding component).

Inguinal hernias continue to be the most common congenital pathology in children needing surgical repair early in life. Approximately 1-3% of children have an inguinal hernia. The incidence is higher in premature babies (3-5%). Almost all inguinal hernias in children are the indirect type (99%). The few direct hernias in children are the result of previous surgery or inguinal floor disruption. Management of inguinal hernias in infants and children is straightforward: outpatient surgery after diagnosis for most cases. The procedure consists of high ligation of the hernial sac. Incidence of developing a recurrent inguinal hernia is around 0.8%. Most recurrences occur two years after the initial surgery. Several factors play a role in increasing hernia recurrence. These are: 1) Missed sac or inadequate ligation of the indirect sac. 2) Children operated for incarcerated inguinal hernias since tissue is more friable and edematous at the time of surgery. 3) Infection of the wound after hernia repair predisposing to tissue breakdown and a higher recurrence rate. 4) Connective tissue disorders (Hurler, Ehlers-Danlos, etc.). 5) Growth failure and poor nutrition. 6) Prematurity has been identified as a comorbid factor in hernia recurrence. 7) Children hernia repair done by non-pediatric surgeons is also a risk factor for recurrence. 8) Conditions causing increase intra-abdominal pressure (VP shunts, posterior urethral valves, bladder exstrophy repair, weight lifting and respiratory conditions) are also related to higher rate of recurrence in children. Repair of the recurrent hernia is done through the inguinal scar or using laparoscopy. The sac is mobilized and ligated. Laparoscopic repair of recurrent inguinal hernia has the advantage of passing through a virgin field reducing damage to vas or vessels and allowing inspection of the area with direct purse string repair of the defect.

Incarceration and strangulation are the most dreaded complications of inguinal hernias in children. Incarceration refers to viscera (bowel, ovaries, and bladder) that protrudes through the inguinal defect and cannot return back to its anatomical position without manipulation or surgery. Bowel incarceration in infants with inguinal hernia is a notable cause of intestinal obstruction in this age group. Strangulation is the ischemic effect caused on the trapped viscera by the incarcerated defect. Incarceration occurs in almost one-third of inguinal hernias. It is more common in children less than one year of age and males. With prolonged incarceration there can also occur testicular infarction. In infant girls the normal anatomy is altered when an ovary is trapped in a hernia sac, and these changes make torsion more likely. This risk warrants treating the asymptomatic irreducible ovary as any other incarcerated hernia with urgency. Incarceration increases the rate of complications, is seen in a younger population of children and increases hospital stay. Children with incarcerated hernia should have a trial of manual reduction followed by prompt repair within the next five to seven days to avoid re-incarceration.

A hydrocele is a collection of fluid in the space surrounding the testicle between the layers of the tunica vaginalis. Hydroceles can be scrotal, of the cord, abdominal, or a combination of the above. A hydrocele of the cord is the fluid-filled remnant of the processus vaginalis separated from the tunica vaginalis. A communicating hydrocele is one that communicates with the peritoneal cavity by way of a narrow opening into a hernial sac. Hydroceles are common in infants. Some are associated with an inguinal hernia. They are often bilateral, and like hernias, are more common on the right than the left. Most hydroceles will resolve spontaneously by 1-2 years of age. After this time, elective repair can be performed at any time. Operation is done through the groin and search made for an associated hernia. Aspiration of a hydrocele should never be attempted. As a therapeutic measure it is ineffective, and as a diagnostic tool it is a catastrophe if a loop of bowel is entrapped. A possible exception to this is the postoperative recurrent hydrocele. Abdomino-scrotal hydrocele (ASH), also known as 'hydrocele en bissac', is a very rare condition seen in infants consisting of a collection of fluid in the tunica vaginalis extending through the inguinal canal into the abdominal cavity. Clinically, the child with an inguino-scrotal hydrocele has an abdominal mass of variable size and firm consistency characterized by increase in tension of the hydrocele when squeezing the abdominal mass and vice versa. The abdominal compartment can be retroperitoneal or properitoneal. An increasing pressure within the hydrocele is transmitted above the deep inguinal ring because of the inexpansible musculofascial covering of the inguinal canal. The diagnosis of an abdomino-scrotal hydrocele is made with the help of ultrasound or MRI showing the fluid filled cavities in both the abdominal (pelvic) and scrotal compartments in communication. ASH should be differentiated from other cystic tumors of the abdominal cavity such as hydronephrosis, bladder diverticulum, mesenteric cysts and lymphangiomas. ASH has been found to cause obstructive uropathy, reduced blood supply to the testis or hemorrhage. Total excision of the abdomino-scrotal hydrocele through an inguinal approach is the proposed treatment of choice.

The undescended testis is a term we use to describe all instances in which the testis cannot be manually manipulated into the scrotum. The testes form from the medial portion of the urogenital ridge extending from the diaphragm into the pelvis. In arrested descent, they may be found from the kidneys to the internal inguinal ring. Rapid descent through the internal inguinal ring commences at approximately week 28, the left testis preceding the right. Adequate amounts of male hormones are necessary for descent. The highest levels of male hormones in the maternal circulation have been demonstrated at week 28. Thus, it appears that failure of descent may be related to inadequate male hormone levels or to failure of the end-organ to respond.

The undescended testes may be found from the hilum of the kidney to the external inguinal ring. A patent processus vaginalis or true hernial sac will be present 90% of the time. The incidence is about 0.28% of the population, approximately 50% occurs on the right, 25% on the left, and 25% occurring bilaterally.

The diagnosis of undescended testes is usually made by the parents or first examining physician. The important point is the absolute necessity of distinguishing between retractile testes and the true undescended testes. Testes that can be drawn to the scrotum, even if they retract again, are retractile testes and not undescended, the squatting position may aid in helping descend the testes for exam. Retractile testis needs no further surgical management.

Since Leydig cell degeneration can occur after age two, present recommendations are for orchiopexy before age 2. Although testicular malignancy is rare, undescended testes have a 40-50 times higher incidence of developing seminomas. This can occur in the contralateral normally descended testis as well as the undescended testis. Surgical repair does not reduce the incidence of malignancy, but does allow for examination and earlier detection. Another reason for surgical repair is the higher incidence of trauma and torsion in the undescended testis. Bilateral undescended testes may be initially treated with a four-week course of human chorionic gonadotrophin. Approximately 15-30% of patients will have descent with this therapy. Surgical repair is most commonly performed by a Dartos pouch technique. Laparoscopy helps in non-palpable undescended testis by identifying those testes that did not developed, suffered an ischemic intrauterine event, and in performing first stage Steven-Fowler technique.

Whenever a child is born with an empty scrotum, the physical examination should include a diligent palpable search for the undescended testis in the inguinal, femoral, perineal or medial thigh areas. Testes palpable in areas away from the normal descent from the retroperitoneum to the scrotum are termed ectopic testis. An ectopic testis is caused by misallocation of the ipsilateral genito-femoral nerve controlled stimulation causing the gubernaculum to migrate to the wrong site because the chemotactic signal is arising from this wrong place. Testes palpable in the inguinal canal or found intra-abdominally are termed undescended. Compared with undescended testes, ectopic testes are extremely rare found most commonly in the perineal ipsilateral area. Other sites include the femoral canal, suprapubic region (at base of the penis), medial thigh, preperitoneal, umbilical, contralateral scrotum or associated with gastroschisis. The perineal testis is particularly subject to trauma. Management is orchiopexy as soon as the diagnosis is established. The most effective route of approach for repair is inguinal allowing replacement of the testis into the corresponding hemiscrotum without difficulty. Other surgeons use a low scrotal approach due to the low incidence of concomitant hernia. Because of the histopathologic features involved, prognosis is better than that associated with cryptorchidism.

D. Mediastinal Cysts, Thymoma & Myasthenia Gravis

Mediastinal cysts identified in children are classified according to the compartment where they arise as: anterior (extends to the sternum, thoracic inlet and anterior border of the heart), middle (between anterior mediastinum and anterior borders of the vertebrae) or posterior mediastinum. Although usually asymptomatic, they require excision for purpose of diagnosis and avoidance of symptoms such as chest pain, airway obstruction, hemoptysis or dysphagia. Diagnosis can be accomplished with the use of CT‑Scan, US and esophagogram. Some of the most common encounter cysts in the mediastinum are: bronchogenic cysts, neurenteric cysts, pericardial cysts, cystic hygroma, thymic and dermoid cysts.

The thymus remains quite prominent in the anterior mediastinum during the first year of life causing discrepancy between a normal and hyperplastic gland. Involution occurs in response to stress and sepsis. Rebound hyperplasia after involution can be seen after cardiac surgery, major burns and chemotherapy. Thymoma is the most common neoplastic tumor found in the thymus of children and adults. There is a close relationship between myasthenia gravis and thymoma. Most thymic tumors in children are benign, share a low rate of association with myasthenia gravis and a favorable prognosis. Thymomas are considered malignant on the basis of macroscopic and microscopic capsular invasiveness. The most significant predictors of long-term survival of thymoma include complete excision, stage I disease, and lymphocytic histology. Management of thymoma entails surgical resection through a median sternotomy. To increase survival a policy of aggressive, complete surgical resection of all thymomas is advice. Thymoma behaves as a rather indolent tumor, with most deaths from causes unrelated to thymoma or its direct treatment. Chemotherapy is reserved for patients with refractory or metastatic disease. Thymomas are moderately radiosensitive but radiation therapy is not an attractive option for children due to side-effects on developing organs.

Children constitute 10% of all cases of Myasthenia Gravis (MG) with three individual forms identified: neonatal, genetic or juvenile. The neonatal phase is transient, associated with a newborn whose mothers have MG and the baby recovers completely after several days or weeks. Genetic MG is not associated to a parent with MG with symptoms confined to ptosis and almost no weakness. The juvenile phase of MG is similar to the adult phase occurring after the age of ten. Symptoms include fluctuating weakness and fatigue in the ocular (diplopia), facial (ptosis), bulbar or limb muscles, weakness, fatigability, ptosis and diplopia. The child develops motor weakness, preservation of sensation, coordination and deep tendon reflex. MG is an autoimmune disease in which there is loss of acetylcholine receptors at the neuromuscular junction. Thymic enlargement occurs in patients with MG. MG is best managed: 1) enhancing neuromuscular transmission with cholinesterase inhibitors though the effect is partial with time; 2) using immune suppression with steroids, azathioprine or cyclophosphamide; 3) with short term immune therapy including plasma exchange or intravenous immune globulin; 4) removal of the thymus (thymectomy) if its enlarged or the child has increase medication requirements.

E. Umbilical Hernias & Granulomas

Between the sixth and tenth gestational week, the developing gastrointestinal tract is partially extruded into the umbilical cord with return into the abdomen by the tenth week. By the time of birth, the umbilical ring has become entirely closed by the developing abdominal wall except for the space occupied by the cord, which contains the umbilical vein, paired umbilical arteries, and the fibrous remnants of the urachus and omphalomesenteric duct (yolk sac). After ligation of the cord, the vessels thrombosed and the cord dries and sloughs off, leaving a granulating surface that heals by cicatrization and is covered by epithelium. This is followed by scar contraction and retraction of the umbilicus. It is believed that most umbilical hernias occur through the cephalad portion of the umbilical ring, where the contracted scar around the obliterated umbilical vein is less dense than in the caudal portion of the scar. Umbilical hernias are very common, especially in prematures, blacks, and certain syndromes, such as Down's. The incidence decrease with age since many will close spontaneously. The diagnosis is made by physical exam; there is a fascial defect at the umbilicus. Complications such as strangulation or incarceration are extremely rare in children.

Umbilical strapping should not be done since it does not promote closure and may lead to skin erosion. Elective repair is usually delayed until after five years of age since closure may occur spontaneously or the defect may get smaller, allowing easier repair. Operative repair includes excision of the sac and horizontal one-layer closure through a small infraumbilical incision.

Persistent umbilical swelling and discharge during the neonatal period is of serious concern to both parents and physicians. Among umbilical swelling, the umbilical granuloma is one of the most commonly seen condition in the pediatric practice. The normal granuloma, a common inflammatory reaction to the resolving umbilical stump of a newborn should disappear by the 2nd to 3rd week of life after proper hygiene. Persistent beyond this time will need some type of therapy. Umbilical granuloma is managed with 75% Silver nitrate stick application. Silver nitrate is not innocuous and when apply liberally can cause a minor burn of the periumbilical skin area of the baby. Caution must be observed while applying Silver nitrate; careful drying the umbilical exudate to prevent periumbilical spillage, and discussion with parent that burns may occur but apparently are not serious. Whenever Silver nitrate therapy fails and discharge persists, or contains urine or fecal material, the physician should suspect that the child has either a patent urachus or omphalomesenteric duct remnant as both conditions resemble the common umbilical granuloma seen in general practice. Ultrasound studies of the periumbilical area looking for a cyst, masses or fixed bowel loops can help determine the presence of such congenital remnants. Management of the persistent umbilical granuloma is surgical with double ligature, cauterization of the base or formal umbilical exploration.

F. Omphalocele and Gastroschisis

The three most common abdominal wall defects in newborns are umbilical hernia, gastroschisis and omphalocele. Omphalocele is a milder form of primary abdominoschisis since during the embryonic folding process the outgrowth at the umbilical ring is insufficient (shortage in apoptotic cell death). Bowel and/or viscera remains in the umbilical cord causing a large abdominal wall defect. Defect may have liver, spleen, stomach, and bowel in the sac while the abdominal cavity remains underdeveloped in size. The sac is composed of chorium, Wharton's jelly and peritoneum. The defect is centrally localized and measures 4‑10 cm in diameter. A small defect of less than 2 cm with bowel inside is referred as a hernia of the umbilical cord. There is a high incidence (30‑60%)of associated anomalies in patients with omphalocele. Epigastric localized omphalocele are associated with sternal and intracardiac defects (i.e., Pentalogy of Cantrell), and hypogastric omphalocele have a high association with genito‑urinary defects (i.e., Cloacal Exstrophy). All have malrotation. Cardiac, neurogenic, genitourinary, skeletal and chromosomal changes and syndromes are the cornerstones of mortality. Antenatal diagnosis may affect management by stimulating search for associated anomalies and changing the site, mode or timing of delivery. Cesarean section is warranted in large omphaloceles to avoid liver damage and dystocia. After initial stabilization management requires consideration of the size of defect, prematurity and associated anomalies. Primary closure with correction of the malrotation should be attempted whenever possible. If this is not possible, then a plastic mesh/silastic chimney is fashioned around the defect to cover the intestinal contents and the contents slowly reduced over 5‑14 days. Antibiotics and nutritional support are mandatory. Manage control centers around sepsis, respiratory status, liver and bowel dysfunction from increased intraabdominal pressure.

The exact embryology of gastroschisis is unclear. The defect is always to the right of the midline with a normally attached umbilical cord. Theories include failure of the right lateral somatopleure to form properly, intrauterine rupture and intrauterine vascular accident leading to ischemia of the right developing rectus. Associated anomalies are rare, with an 11% incidence of atresia. Treatment is identical to omphalocele except more urgent to avoid problems with the exposed bowel (dehydration and hypothermia). More than 90% babies survived. Prenatal diagnosis has brought a controversy toward optimal mode of delivery (Cesarean vs vaginal). The appearance of the bowel is edematous, matted and foreshortened due to exposure to amniotic fluid, and the constrictive vascular effects of a small defect. G. Epigastric Hernias

Congenital epigastric defects occur anywhere in the linea alba from the navel to the xiphoid process. They represent almost 5% of all hernias defect that presents in children. Most epigastric hernias occur in the midline, are small (15-25 mm), asymptomatic and reducible. Multiple fascial defects can also be present in 20% of all cases. The defect might arise congenitally from an abnormally wide orifice of a blood vessel during development of the linea alba. The bump is the result of a piece of preperitoneal fat stuck through the fascial defect. Tenderness is an unusual symptom while growth of the defect occurs with time. Most surgeons recommend repair of the defect at the time of presentation. Repair is an outpatient procedure done under general anesthesia with low morbidity and risk of recurrence. Voluminous epigastric hernia (5-10 cm) with a sac that contains epiploic appendages or viscera (ileum loops, stomach) has also been rarely reported in infants.

G. Epigastric Hernias

Congenital epigastric defects occur anywhere in the linea alba from the navel to the xiphoid process. They represent almost 5% of all hernias defect that presents in children. Most epigastric hernias occur in the midline, are small (15-25 mm), asymptomatic and reducible. Multiple fascial defects can also be present in 20% of all cases. The defect might arise congenitally from an abnormally wide orifice of a blood vessel during development of the linea alba. The bump is the result of a piece of preperitoneal fat stuck through the fascial defect. Tenderness is an unusual symptom while growth of the defect occurs with time. Most surgeons recommend repair of the defect at the time of presentation. Repair is an outpatient procedure done under general anesthesia with low morbidity and risk of recurrence. Voluminous epigastric hernia (5-10 cm) with a sac that contains epiploic appendages or viscera (ileum loops, stomach) has also been rarely reported in infants.

H. Recurrent Inguinal Hernias

Inguinal hernias continue to be the most common congenital pathology in children needing surgical repair early in life. Approximately 1-3% of children have an inguinal hernia. The incidence is higher in premature babies (3-5%). Almost all inguinal hernias in children are the indirect type (99%). The few direct hernias in children are the result of previous surgery or inguinal floor disruption. Management of inguinal hernias in infants and children is straightforward: outpatient surgery after diagnosis for most cases. The procedure consists of high ligation of the hernial sac. Incidence of developing a recurrent inguinal hernia is around 0.8%. Most recurrences occur two years after the initial surgery. Several factors play a role in increasing hernia recurrence. These are: 1) Missed sac or inadequate ligation of the indirect sac. 2) Children operated for incarcerated inguinal hernias since tissue is more friable and edematous at the time of surgery. 3) Infection of the wound after hernia repair predisposing to tissue breakdown and a higher recurrence rate. 4) Connective tissue disorders (Hurler, Ehlers-Danlos, etc.). 5) Growth failure and poor nutrition. 6) Prematurity has been identified as a comorbid factor in hernia recurrence. 7) Children hernia repair done by non-pediatric surgeons is also a risk factor for recurrence. 8) Conditions causing increase intra-abdominal pressure (VP shunts, posterior urethral valves, bladder exstrophy repair, weight lifting and respiratory conditions) are also related to higher rate of recurrence in children. Repair of the recurrent hernia is done through the inguinal scar or using laparoscopy. The sac is mobilized and ligated. Laparoscopic repair of recurrent inguinal hernia has the advantage of passing through a virgin field reducing damage to vas or vessels and allowing inspection of the area with direct purse string repair of the defect.

I. Acute Scrotum & Epididymitis

The term acute scrotum refers to signs and symptoms associated with local inflammation of the scrotum that appears suddenly and usually is not associated with trauma. Is a common urological emergency. Such signs and symptoms include scrotal pain, swelling, redness and heat. The most common causes of acute scrotum in children constitute testicular torsion, appendix testis torsion, epididymitis, orchitis and pyocele. Testicular torsion, a surgical emergency, occurs in 15% of all cases and is the most important condition to diagnose and manage early in order to avoid testicular loss, fertility problems and medico-legal issues. Testicular loss commences past the twelve hours of initiation of symptoms. Beyond twenty-four hours of symptoms testicular loss in the norm. This is the main reason why in the absence of ancillary studies surgeons immediately explore  the acute scrotum. The two most commonly used preoperative studies are testicular scan and color Doppler ultrasound. Testicular scans reliable show whether the testes have vascular flow or not, but are difficult to be obtained in the middle of the night. Doppler ultrasounds are operator dependant and when done by experienced physician can help reduce the number of emergency operations and hospitalization days. Clinical judgment by the surgeon is probably the most important factor in assessing testicular salvage. In the face of doubt the next step in management is immediate surgical scrotal exploration.

Idiopathic scrotal edema is a very uncommon cause of acute scrotal swelling, but considered the commonest cause of the 'acute scrotum' in prepubertal boys. Idiopathic scrotal swelling is characterized by edema and erythema of the scrotal wall, is usually bilateral and can sometimes involve the shaft of the penis. The swelling and erythema can extend into the abdominal wall and perineum. Children affected with acute scrotal swelling are four to six years in age with symptoms present for less than 24 hours at the time of initial medical evaluation. The cause of the swelling is usually not identified but can be associated to reaction to an allergen, bug bite, contact dermatitis or angioneurotic edema. Leukocytosis is absent, urinalysis is usually normal and urine culture is sterile. Peripheral eosinophilia is present in some patients. A connection with trauma, periurethral disease, or streptococcal disease appears unlikely. The differential diagnosis includes torsion of the testis or one of the testicular appendages, hydrocele, varicocele, trauma, tumor, idiopathic scrotal edema, and Henoch-Schnlein purpura. Color Duplex ultrasound of the scrotum will show increase testicular blood flow and thickening of skin and muscle of the scrotum. Exploration is required when a normal testis cannot absolutely be identified. Swelling usually resolves within two to five days. Management consists of bed rest, reassurance, and oral histamine.

Acute inflammation of the epididymis is an infectious process which usually occurs during adolescent years, very rarely during prepubertal ages. The infectious process is caused by a distal urethral obstruction, ectopic ureter entering the seminal vesicles or epididymis, or after instrumentation. Bacterial or viral organisms are involved in the infectious process. Epididymitis seems to be more common than acute testicular torsion. Early clinical manifestations of epididymitis include scrotal edema, pain, erythema, tenderness with an associated reactive hydrocele. The epididymis turns elongated and exquisitely tender to palpation. The differential diagnosis includes testicular torsion, torsion of the testicular appendage or idiopathic scrotal edema. The urinalysis will demonstrate pyuria with bacteriuria. Leukocytosis is also identified. Color Doppler ultrasound or testicular scans can determine rapidly if we are dealing with torsion due to reduced or absent testicular blood flow in need of urgent surgery. In the event of doubt or absence of imaging studies the diagnosis of an acute scrotum requires scrotal exploration. Management of epididymitis includes intravenous antibiotics, pain medication, scrotal support and bed rest. Further renal ultrasound and excretory urography are needed after the episode subsides to determine a congenital urologic anomaly.