Pediatric Hydrocele and Hernia Surgery

During fetal development, the testicle is located below the kidney, within the peritoneal cavity. As the testicle descends through the inguinal canal and into the scrotum, it is accompanied by a saclike extension of peritoneum, otherwise known as the PV. After the testicle descends, the PV obliterates in the healthy infant and becomes a fibrous cord with no lumen. The distal tip of the PV remains as a membrane around the testicle (ie, the TV).

Normally, the inguinal region and scrotum should not connect with the abdomen. Neither abdominal organs nor peritoneal fluid should be able to pass into the scrotum or inguinal canal. If the PV does not close but remains patent, it is referred to as a PPV. If the PPV is small in caliber and only large enough to allow fluid to pass, the condition is referred to as a communicating hydrocele. If the PPV is larger, allowing ovary, intestine, omentum, or other abdominal contents to protrude, the condition is referred to as a hernia.

Multiple theories exist regarding the failure of PV closure. Smooth muscle has been identified in PPV tissue but not in normal peritoneum. The amount of smooth muscle present may correlate with the degree of patency. For example, higher amounts of smooth muscle have been found in hernia sacs than in the PPV of hydroceles. Investigation continues to determine the role of smooth muscle in the pathogenesis of this condition.

Most hernias and hydroceles in children are due to idiopathic failure of the PV to close. Any condition that increases intra-abdominal pressure can delay or inhibit this closure.

The following conditions are associated with a higher incidence of hernia or hydrocele:

• Cryptorchid testis
• Hypospadias
• Ambiguous genitalia
• Epispadias and exstrophy of the bladder
• Ventriculoperitoneal shunt
• Liver disease with  ascites
• Abdominal wall defects
• Continuous ambulatory peritoneal dialysis
• Prematurity
• Low birth weight
• Family history of hernia or hydrocele
• Hydrops
• Meconium peritonitis
• Chylous ascites
• Cystic fibrosis
• Connective tissue disease
• Mucopolysaccharidosis

Reactive hydroceles result from inflammation and fluid accumulation in the TV around the testicle, even though the PV is closed. A reactive hydrocele can result from the following factors:

• Trauma
• Torsion
• Infection (eg, epididymo-orchitis)
• Abdominal or retroperitoneal operations that impair lymphatic drainage

United States statistics

The incidence of hernias is 10-20 per 1000 live births and is much higher after premature birth. Whereas hernias are more commonly located on the right side, as many as 10% are bilateral.

Age- and sex-related demographics

The incidence of PPV decreases with age. In newborns, 80-94% have a PPV. Hernias are 20 times more common in premature infants who weigh less than 1500 g than in babies born at term. As many as 30% of adults are discovered to have a PPV at autopsy. Why all PPVs do not develop into a hernia or hydrocele is not understood.

Hernias are six times more common in boys than in girls. Bowel incarceration is more common in females than in males. In females, an ovary or fallopian tube incarcerates more frequently than the bowel does. Therefore, the overall incidence of bowel strangulation is lower in females than in males.

The greatest risk associated with a hernia involves an intra-abdominal organ becoming trapped within the hernia sac. This condition is referred to as incarceration of the organ. If bowel becomes incarcerated, it may become edematous. The increased pressure may impair venous drainage, leading to more edema, which may impair arterial inflow of the bowel. This can ultimately cause bowel ischemia and possible rupture.

In a male, pressure placed on the spermatic cord by an incarcerated hernia may affect blood flow to the testis. When bowel perfusion is affected, a strangulated hernia exists. This condition can lead to perforation of the entrapped bowel, peritonitis, sepsis, and even death. Incarcerated or strangulated hernia is therefore a surgical emergency. If a strangulated bowel is reduced surgically at an early stage, viability may be preserved and bowel resection avoided. In children with a painful nonreducible hernia, incarceration should be suspected, necessitating emergency evaluation.

The omentum may become entrapped in a hernia, causing chronic abdominal pain with a persistent inguinal mass.

In females, the ovary or fallopian tube can enter hernia sacs and become incarcerated or strangulated. An incarcerated ovary is an urgent problem that may result in inguinal pain and infarction of the ovary. An incarcerated ovary does not carry the same risk of sepsis as is seen with bowel incarceration and perforation.

With open surgery, ipsilateral recurrence rates are lower than 1%. The ipsilateral recurrence rate after laparoscopic inguinal hernia repair is 3.4%. Recurrences are usually associated with comorbid conditions. The incidence of a metachronous contralateral hernia is inversely related to age and can be as high as 12%.

A bulge in the groin or scrotal enlargement is the classic presentation of hernia or communicating hydrocele. Pain is generally not a prominent feature but may occur if a hydrocele expands quickly; tension in the wall may cause milder pain. Severe pain raises concern about a strangulated hernia. Very rarely, a hydrocele may become infected and cause pain.

Frequently, parents report an intermittent bulge. The bulge may reduce at night in the supine position. A history of vomiting, colicky abdominal pain, or obstipation suggests bowel obstruction, which may occur with an incarcerated or strangulated hernia.

Examine the child in the supine and standing positions. If a bulge is apparent in the standing position, lay the child in the supine position. Resolution of the bulge in the supine position suggests a hernia or a hydrocele with a patent processus vaginalis (PPV).

If the bulge is not readily apparent, perform a maneuver to increase intra-abdominal pressure. For example, have the child simulate blowing up a balloon, cough, or press firmly on the abdomen. Restraining a baby's hands above his or her head causes the baby to struggle, potentially revealing an occult bulge that is not visible otherwise.

Transillumination of the scrotum displays fluid in the tunica vaginalis (TV), suggesting a hydrocele. However, this test does not fully exclude a hernia, because the bowel may also transilluminate.

Bowel sounds in the scrotum are strongly suggestive of a hernia. A bulge below the inguinal ligament is suggestive of lymphadenopathy.

Examiners may try to elicit the "silk glove" sign. Gently passing the fingers over the pubic tubercle may reveal a PPV. The thickened cord of a hernia or hydrocele sac within the spermatic cord provides the feel of two fingers of a silk glove rubbing together.

Unless a PPV results in hernia or hydrocele, it often goes undetected during physical examination.

Hernia

Indirect hernias protrude through the internal inguinal ring, lateral to the inferior epigastric vessels. They are caused by failure of the processus vaginalis (PV) to obliterate. Most inguinal hernias in children are the indirect type. The hernia may extend down the inguinal canal toward the labia or scrotum.

Complete inguinal hernias are indirect hernias that extend into the scrotum. The anatomic defect is similar to the defect of a communicating hydrocele, though the PPV is more widely patent in hernias.

Direct hernias protrude directly through the floor of the inguinal canal and are medial to the inferior epigastric vessels. In children, these hernias are rare and are usually observed only after prior inguinal surgery.

Hydrocele

Communicating hydroceles involve a PPV that extends all the way into the scrotum. In this case, the PPV is continuous with the TV, which surrounds the testicle. The anatomic defect is identical to the defect with an indirect hernia; however, the communication is smaller, so only fluid can pass into the PPV.

Noncommunicating hydroceles contain fluid confined to the scrotum within the TV. The PV is obliterated, and thus the fluid does not communicate with the abdominal cavity. Such hydroceles are common in infants, and the hydrocele fluid is usually reabsorbed before the infant reaches the age of 1 year.

Reactive hydroceles are noncommunicating hydroceles that develop from some inflammatory condition in the scrotum (eg, trauma or infection).

Hydrocele of the cord occurs when the PV obliterates above the testicle. A small communication with the peritoneum persists, and the PV may be open as far down as the top of the scrotum. A saclike area within the inguinal canal fills with fluid. The fluid does not extend into the scrotum.

Hydrocele of the canal of Nuck occurs in girls when fluid accumulates within the PV in the inguinal canal.

Abdominoscrotal hydrocele results from a minuscule opening in the PV. Fluid enters the hydrocele and becomes trapped. The hydrocele continues to enlarge and eventually bulges upward into the abdomen, causing a fluid-filled mass in the abdomen.

Laboratory evaluation is generally not essential to the evaluation of hydroceles and hernias.

Leukocytosis may be a sign of a strangulated hernia. Leukocytosis with a higher percentage of neutrophils suggests an infectious or inflammatory process (eg, epididymo-orchitis).

Indications for scrotal or inguinal ultrasonography (US) include the following:

• Suggestion of torsion of a testicle or ovary (duplex US should be used to evaluate blood flow)
• Suggestion of tumor of the spermatic cord
• Suggestion of tumor of the testicle
• Trauma and concern about testicular rupture

US may have a role to play in the evaluation of asymptomatic patent processus vaginalis (PPV). As noted (see Presentation), PPV can be difficult to diagnose on the basis of physical examination.

When a unilateral inguinal hernia is discovered on physical examination, the chance of PPV on the contralateral side can be as high as 63% in children younger than 2 months; this figure decreases with age. As many as 20% of patients develop an inguinal hernia on the contralateral side, but it is controversial whether to proceed with any type of imaging preoperatively or exploration at the time of surgery. This has encouraged interest in US to assess a contralateral PPV in the preoperative period.

Research studies have shown a positive correlation between US findings of PPV and intraoperative findings of PPV. The rate of false-negative results (ie, US findings that are normal, even when a proven PPV exists) is unknown. Further research with this modality may clarify the risk of developing a contralateral hernia later, but at present, US is not considered to be routine in the evaluation of any type of PPV.

Abdominal plain films are used to rule out bowel obstruction due to an incarcerated or strangulated hernia.

Manual reduction of incarcerated hernias is advised when feasible. Necrotic bowel is usually so swollen that it cannot be reduced manually. An incarcerated hernia can progress to perforation in as little as 2 hours. For these two reasons, parents and primary care physicians are encouraged to reduce hernias. Surgical consultation is critical even if the hernia is reduced successfully.

In the emergency department, manual reduction of incarcerated hernias incorporates the following steps:

• Administer sedation to the child
• Elevate the child's buttocks, and apply a padded ice pack to the inguinal area to reduce swelling
• Slowly compress the hernia at its most distal aspect while holding two fingers of the opposite hand at the neck of the hernia sac, at the level of the internal inguinal ring; this technique prevents the hernia from being pushed alongside the inguinal canal
• Maintain pressure continuously; 10 or more minutes of slow continuous pressure is often required
• The hernia should slide slowly back into the abdomen

A child who has undergone incarcerated hernia reduction should be observed closely after the procedure. In rare instances, necrotic bowel can be reduced back into the abdomen. This bowel may then perforate and result in peritonitis, which necessitates emergency exploration with resection of the necrotic bowel to prevent sepsis.

No medical therapy is effective for a hernia or a communicating hydrocele. Aspiration and injection of sclerosing agents have been recommended for noncommunicating hydroceles in adults, but this therapy is relatively contraindicated in children. Because most hernias and hydroceles in children are associated with a patent processus vaginalis (PPV), sclerosing agents may damage intra-abdominal contents and are not likely to correct the underlying pathology.

Anti-inflammatory agents may be used in the setting of a reactive hydrocele. Antibiotic therapy is often prescribed for infectious epididymo-orchitis with a reactive hydrocele.

A study by Esposito et al found that hydroceles can develop in as many as 12% of children undergoing surgery for varicocele (varicocelectomy) and that the incidence varies with the type of procedure performed.[1] Preservation of the lymphatic vessels at the time of surgery reduces the risk of later hydrocele. Conservative management (observation or aspiration) results in resolution of 80% of these hydroceles. Surgical correction was required in only one third of these hydroceles that occurred after varicocelectomy.

Although hernias and hydroceles are similar, their natural histories differ. Spontaneous closure does not occur in frank hernias, and the risk of incarceration is significant. In particular, the risk of incarceration is high in premature children. As many as 60% of hernias in premature infants become incarcerated within the first 6 months after birth; thus, hernias should be corrected as soon as possible in these babies. For these reasons, surgical repair is generally accepted as the appropriate treatment for an inguinal hernia in children and adults.[2, 3, 4]

Unlike hernias in infants, many hydroceles in newborns resolve because of spontaneous closure of the PPV early after birth. The residual noncommunicating hydrocele does not wax and wane in volume, and no silk glove sign is present. The fluid in the hydrocele is usually reabsorbed before the infant reaches age 1 year. Because of these facts, observation is often appropriate for hydroceles in infants.

The following are indications for hydrocele repair:

• Failure to resolve by age 2 years - A study by Kurobe et al found that one third of patients older than 2 years with asymptomatic hydrocele experienced spontaneous resolution ^[5] ; the authors accordingly recommended an initial period of conservative management before surgery in children with asymptomatic hydrocele, evan after the age of 2 years 
• Continued discomfort
• Enlargement or waxing and waning in volume
• Unsightly appearance
• Secondary infection (very rare)

A hernia or hydrocele may protrude intermittently. Not infrequently, a bulge in the child's groin is noted by the parents or a primary care physician. Often, this bulge cannot be reproduced during a consultation, but thickening of the spermatic cord structures on the same side with a history of a bulge or a "silk glove" sign is suggestive of a PPV. Such a situation is a sufficient indication for inguinal exploration. A photograph of the area when the bulge is present may help clarify the diagnosis.

The following specific considerations apply to the timing of surgery:

• If an incarcerated hernia cannot be reduced or signs suggest that the hernia is strangulated, schedule surgery on an emergency basis
• In full-term infants with no history of incarceration, schedule surgery as soon as possible on an outpatient basis
• For preterm neonatal intensive care unit (NICU) infants weighing 1800-2000 g, schedule surgery before hospital discharge
• For formerly premature infants younger than 60 weeks’ postconceptual age, schedule surgery as soon as possible with 24-hour postoperative monitoring for apnea and other anesthesia-related complications

Operative details

Examine the child to confirm the presence of testes. Make a small inguinal incision.

Enter the inguinal canal and dissect the processus vaginalis (PV), which is the hernia sac or hydrocele sac, free of the vas deferens and vessels. Optical magnification is beneficial, especially in premature infants and small children.

If the sac contents (ie, abdominal organs, fluid) appear normal, reduce them into the abdomen. If the contents of the sac appear compromised or cannot be reduced, open the sac and enlarge the inguinal ring. Ischemic bowel may show improvement in vascularity. Necrotic contents should be resected. Ligate the sac at or above the internal ring.

If the lesion involves the testicle, the testicle is delivered into the incision, and the distal end of the sac is excised or everted around the testes (Bottle operation). These procedures are advised to avoid the later development of a postoperative noncommunicating hydrocele.

Reposition the testis in the scrotum. If the testis does not remain in the bottom of the scrotum, cryptorchidism may be present, and orchiopexy should be performed at that time.

Inspect the internal ring to ensure that any abdominal contents are reduced completely. Reinforce the internal ring if it was opened or if it appears larger than normal caliber.

Local anesthesia may be injected subcutaneously, or an inguinal nerve block may be performed. Sew the fascial layers and skin closed.

Contralateral exploration with inguinal hernias is performed as indicated. When an inguinal hernia is present, some urologists and surgeons perform a contralateral groin exploration. This is intended to detect an occult PPV (5% of cases) that may lead to a hernia on the opposite side (metachronous contralateral hernia.)

The Goldstein test can be used to determine when to perform a contralateral exploration, but this may not be conclusive. In this test, the abdomen is insufflated with air or gas through the hernia sac, which is opened during surgery. Crepitus in the opposite groin is a positive test result, suggesting a contralateral PPV and warranting a contralateral exploration. Alternatively, a laparoscope can be used to detect an occult contralateral PPV.

Role of laparoscopy

Laparoscopy has an evolving role in hydrocele and hernia surgery.[6, 7] Exploratory laparoscopy may be carried out through a separate incision at the umbilicus or through the hernia sac, once it has been opened. This allows inspection of the contralateral inguinal ring and assessment of patency. Additional procedures may then be performed as needed.

Laparoscopic hernia repair has not been performed as commonly in children as in adults. Several European centers have used a technique in which the hernia sac is not excised but rather simply closed at the neck with suture. Mesh has not been used as commonly in children as in adults. Initial results were favorable, though recurrence rates were higher than with open repair.

A series by Kaya et al from Germany reported favorable results with the laparoscopic approach as compared with reduction and repair of incarcerated inguinal hernias in children.[8] The authors reported no complications and no recurrences; however, the details and length of follow-up were not clearly defined.[8]

A study by Saka et al from Japan comparing laparoscopic extraperitoneal closure with traditional open repair found that the laparoscopic technique was safe and effective for inguinal hernias and hydroceles in children, regardless of age, sex, or incarceration, and suggested that this approach could lower the incidence of metachronous contralateral hernias.[9]

In a systematic review of 15 published studies (N = 2920) of laparoscopic pediatric hydrocele repair, Jin et al found that this procedure appeared to be safe and effective.[6] Most of the studies used an extraperitoneal approach; only a few used an intraperitoneal approach. The hydrocele sac was left alone in 10 of the studies and was resected or transected in only five. Nonabsorbable sutures were more often used to ligate the hydrocele sac than absorbable materials were. Operative complications were infrequent and were not significantly influenced by hydrocele subtype, surgical approach, suture material, or management of the hydrocele sac.

A systematic review and meta-analysis of laparoscopic and open inguinal repair in children by Kantor et al found no difference between the two approaches with respect to recurrence rate, surgical time, and length of hospitalization; however, laparoscopic repair was associated with a higher risk of wound infection and a lower risk of ascending testis.[10]  The laparoscopic approach also afforded the surgeon the chance to explore and repair the contralateral side if necessary.

A retrospective single-center study (N = 2018) by Duan et al found lparoscopic percutaneous extraperitoneal closure with peritoneum reinforcement (LPECPR) to be a safe and effective approach for pediatric inguinal hernia and to have a low recurrence rate (0.15%).[11]

Single-port laparoscopic approaches have been developed that appear to be both effective and safe.[12, 13, 14, 15, 16, 17, 18, 19, 20]

The percutaneous internal ring suturing (PIRS) technique appears to be safe and effective for laparoscopic repair of pediatric inguinal hernia.[21, 22] It may be especially useful in girls, who lack a spermatic cord and other structures that may lead to complications with this approach in boys.[23]

The overall operative complication rate associated with hydroceles and hernias is 1.7-8%.

Infertility may result from bilateral injury to the vas deferens or injury to the vas of a solitary testis. Presence of a vaslike structure in the pathology specimen does not necessarily indicate injury to the vas: As many as 6% of specimens contain müllerian ductal remnants with a histologic appearance very similar to that of the vas.

An incarcerated hernia may compromise blood flow to the testicle before surgery. The rate of testicular atrophy after repair of an incarcerated hernia can be as high as 19%. Testicular atrophy may also result from intraoperative injury to the testicular blood supply.

As with any surgical procedure, hematomas may occur. A hematoma usually need not be explored unless the hematoma continues to enlarge or becomes infected. Scrotal elevation is encouraged, and analgesics are administered.

Wound infections can occur.

Hypesthesia and neuropathic pain can result from nerve entrapment or injury.

Secondary cryptorchidism may result from excessive scar formation and ascent of the testicle with growth.

Cord hydrocele may occur after laparoscopic intracorporeal inrepair of inguinal hernia in male pediatric patients; removal of the hernia sac may reduce the risk of this complication.[24]

Recurrence of the hydrocele may be seen in fewer than 5% of cases. If the hydrocele does not disappear spontaneously after 1 year, reoperation is indicated.

Convalescence after hernia or hydrocele surgery is usually straightforward.

For pain control, infants may be given ibuprofen 10 mg/kg every 6 hours or acetaminophen 15 mg/kg every 6 hours. Narcotics should be avoided in young babies because of the risk of apnea. Older children may be given acetaminophen with codeine (1 mg/kg of codeine) every 6 hours.

For 2 weeks after surgery, straddle positions (eg, bicycle) should be avoided to prevent displacement of the mobile testes out of the scrotum, which could become entrapped by fibrous tissue, causing secondary cryptorchidism.

In children of ambulatory age, vigorous activities should be limited as much as possible for 1 month. In children of school age, strenuous activities and active sports should be limited for 4-6 weeks. Because most surgical procedures for pediatric hernia and hydrocele are performed on an outpatient basis, patients may return to school as soon as their comfort level allows (usually 1-3 days postoperatively).