Abstract
Abstract
Pediatric inguinal hernia and hydrocele share a common etiology as well as management. The era of minimal access surgery is challenging the conventional surgical management for pediatric inguinal hernia in particular. This review article aims to highlight the nature of diagnosis and treatment for both hernia and hydrocele and examines both the traditional and contemporary treatment strategies from an evidence-based perspective.
Introduction
Definition and nature of inguinal hernia and hydrocele
During fetal life, the descent of the testis into the inguinal canal and scrotum brings a small pouch of peritoneum alongside. 3 This peritoneal extension is the processus vaginalis. In females, the formation of the labia has the same peritoneal remnant, referred to as the canal of Nuck. 4 The peritoneal canals are obliterated in up to 95–98% of fetuses obliterated before birth.2,3 Failure of this peritoneal fusion results in a spectrum of abnormalities. The degree of fusion failure results in either a hydrocele (hydro: water; cele: collection of fluid) within the scrotum or labia, sometimes extending into the groin, or a hernia (i.e., descent of visceral contents into the inguinal canal and in some scrotum/labia). There are two types of inguinal hernia: direct, where the abdominal musculature is weak and visceral contents protrude through the wall of the inguinal canal and exit via the superficial inguinal ring, and indirect inguinal hernia, where visceral contents pass into the patent processus vaginalis (PPV) via an open deep inguinal ring and exit via the superficial inguinal rings. The latter is the most common finding in children.1–5 Inguinal hernia is 9 times more common in boys than in girls, with the majority occurring on the right (60%), left (25%), and 15% being bilateral.6,7
Diagnosing Inguinal Hernia and Hydrocele
Inguinal hernia
Patients are initially assessed by history and clinical examination. History often reveals a sudden, intermittent appearance of a bulge in the groin during nappy change or when drying after bathing. This is usually seen with straining or crying. The infant or child may appear in discomfort at such times. The child may also have developed an irregular bowl habit. In cases of incarceration with obstruction, the child may be vomiting and have abdominal distention. Clinical examination may be normal. Evidence of recent herniation is indicated by swelling within the inguinal canal structures, often referred to as a thickened spermatic cord. 9 The latter most likely represents edema or fluid within the processus vaginalis and surrounding tissue, as well as cremasteric muscular hypertrophy. If the hernia is incarcerated at the time of examination, a mass is usually felt within the groin. An inability to palpate the upper border of the mass is suggestive of herniation of visceral contents from within the peritoneal cavity, with the caveat to this being an inguinal hernia in a premature infant where tissue layers are thin and the inguinal canal is very short. 9 The scrotum may also appear larger than the contralateral side if the hernia has descended within the scrotal sac. In females, a small mobile mass often appears in the groin or labia, which usually represents an ovary.
Hydrocele
History and clinical examination is important when differentiating hydrocele from hernia. Parents often describe a painless swelling within the scrotum, appearing larger in the evening than the morning or during a viral infection. Examination reveals a fluctuant painless swelling, which may or may not be reducible. Transillumination reveals a fluid-filled scrotum, which may be bilateral. Palpation above the swelling is usually possible, except in the case of a large abdominoscrotal hydrocele.
Preoperative Investigations
The diagnosis for both inguinal hernia and hydrocele is usually clinical. In those older children with indeterminate pain, ultrasound may play a role. 15 Others have also advocated the use of ultrasound in detecting contralateral PPV prior to hernia surgery in children. 16 An abdominal radiograph may confirm bowel obstruction in patients with obstructed hernia. Laparoscopy may be considered as a diagnostic investigation in some carefully selected patients, as it will require general anesthesia.
Indications for Surgery
Inguinal hernia
Surgery is indicated for all pediatric patients where a diagnosis of inguinal hernia has been made. Premature infants with hernia are usually operated on prior to leaving the neonatal intensive care unit (NICU) by most surgeons. 17 Infants under the age of 3 months are usually booked on a soon-available operating list. Older children with few symptoms can be booked electively. 19 Surgical treatment is offered for inguinal hernia to prevent the risk of incarceration and or obstruction, resulting in necrosis of hernia contents as well as surrounding cord structures. In females, torsion of the ovary is also possible.12–14,18,19
Hydrocele
Surgical indication for hydrocele is mostly age dependent. Most surgeons advocate observation in the majority of infants less than 12 months. 17 Others may continue observation for longer, as the majority of PPV will close within the first 12–24 months of life.2–7
Contraindications to surgery (absolute and relative)
There are no absolute or relative contraindications to inguinal hernia or hydrocele repair. Repair is often delayed for other reasons, such as fitness for surgery or abdominal pressure problems, as occurs in the reduction of large abdominal wall defects.
Risks or Potential Benefits/Hazards Pre- and Postsurgery for Pediatric Inguinal Hernia and Hydrocele
Inguinal hernia
Risks of not performing surgery for inguinal hernia include bowel incarceration or necrosis, as well as possible testicular or ovarian compromise and/or necrosis.12–14,18,19 The risk to hernia and its contents becoming incarcerated is greatest in early infancy, 10 with premature infants having an incarceration risk of up to 30%.12–14 The latter is halved in older children.
Hydrocele
Risks of nonoperative management in hydrocele include scrotal enlargement and potential hernia formation. Hydrocele is considered a benign condition, though abdominoscrotal hydrocele may affect testicular morphology (i.e., flattening or elongation), if left untreated. 21 In adults, hydrocele can be associated with an arrest of spermatogenesis. 22
Surgical Options in the Management of Inguinal Hernia and Hydrocele
Inguinal hernia
Depending on the age of the patient and the history of incarceration, the patient may be admitted and the operation carried out within 24–48 hours. A delay is often afforded to allow edema within the inguinal canal to settle. If the hernia is easily reducible and the child older than 3 months, the procedure is usually carried out electively. If a patient presents with incarceration, an attempt at reduction should be made. Reduction should be performed by a trained physician, using analgesia and or sedation. 24 If a hernia remains incarcerated, an operative approach is indicated to reduce and inspect the integrity of hernial contents as well as ligate the hernial sac. Reduction may spontaneously occur prior to a manual attempt, if the infant's buttocks are elevated slightly to assist in the reduction of hernial contents. The hernia is palpated distally while the clinician's fingers locate the proximal neck of the hernia. Compression of the hernia can then occur. The pressure is maintained slowly and consistently until the hernia is reduced. For those with incarceration, the chance of reincarceration is reported to be as high as 15%, if surgery is delayed more than 5 days. 25
Operative Approaches to Inguinal Hernia
Inguinal hernia in children can be repaired through either an open or laparoscopic technique. The laparoscopic technique can be either transperitoneal or -abdominal preperitoneal (TAPP).
Open technique of inguinal hernia repair
An inguinal crease incision is made on the ipsilateral side to the symptomatic inguinal hernia. 26 The procedure involves the separation of the hernial sac from the surrounding cord structures, including cremasteric muscle, vas deferens, and the testicular vessels or round ligament. A ligature is usually applied to the separated sac, and the distal sac is divided. The presence of a contralateral PPV (cPPV) or hernia can be identified by the passage of a 70-degree angled telescope through the hernia sac prior to ligation (hernioscopy). 47 The addition of the pneumoperitoneum, delivered simply by using an 8-Fr nasogastric tube alongside the telescope, improves the visualization of the opposite deep inguinal ring. 47
Laparoscopic technique of inguinal hernia repair
The laparoscopic approach can be performed either transperitoneally28,31,32,47 or through a preperitoneal approach with transperitoneal visualization.29,30 The transperitoneal approach incorporates a telescope through an umbilical port, allowing direct visualization of the deep inguinal rings, followed by the controlled passage of instruments either with or without the assistance of trocars. The technique affords confirmation of the diagnosis, as well as inspection of the contralateral side for the presence of a hernia or PPV. The deep ring is then closed with either an absorbable or nonabsorbable suture either as purse string or similar.28,31,32 A peritoneal flap closure is also possible in using this access method. 33 In the preperitoneal approach, a small hook, loaded with a suture, is passed around the deep ring after making a small inguinal skin incision. The passage of the suture is observed via an endoscope at the umbilicus.29,30 The ligature is then brought extracorporally and tied, thus closing the hernial orifice.
Hydrocele
The surgical procedure is identical to that of the open inguinal herniotomy. Some surgeons do advocate a scrotal approach for older children. 48 If communicating this approach may be associated with a higher recurrence rate, 6 once the PPV is ligated, an attempt should be made to empty the distal fluid, if not already drained. This often requires an incision distally, down to the scrotal tunica vaginalis, to release any residual fluid.
Recommendations Based on Available Levels of Evidence
The open method of inguinal hernia and hydrocele repair is a standard approach worldwide and has been widely reported for over five decades. Studies examining surgical outcome have no controls. Current controversies in pediatric hernia management include the following: 1) the need to detect and treat a contralateral patent deep ring to avoid future herniation; 2) the timing of surgery; and 3) whether to perform the operation open or via a laparoscopic/laparoscopic-assisted approach.
Supporting evidence [Table 1]
The need to detect a contralateral PPV
The majority of evidence to support the clinical relevance for a patent cPPV is based on type II-3 and 3 data, when bilateral exploration was widely performed.34–38 The likelihood of developing a contralateral inguinal hernia is between 8 and 15%.6–8 The laparoscopic evaluation via hernioscopy or umbilical laparoscopy detects cPPV in up to 30–50% of patients28–31,47 and is, therefore, a similar finding to that in open contralateral surgery. Current levels of evidence do not demonstrate any increase in morbidity from the routine treatment of contralateral PPV or hernia when detected laparoscopically.
Adapted from the criteria used by the U.S. Preventive Services Task Force and American Diabetes Association.
The timing of hernia repair
Evidence to support an optimal timing of hernia repair is either level II-3 or III.11–14 A tailored individual approach is usually required and is the unanimous conclusion from most studies. Early repair before discharge is warranted in patients below 50 weeks in conceptual age and/or with a previous history of incarceration. An urgent available list should be accessible for those under the age of 3 months.
Open versus laparoscopic repair
Level I evidence comparing open and laparoscopic approaches to inguinal hernia surgery is limited. Small, single-blinded, randomized, controlled trials, to date, have highlighted areas both for and against laparoscopic repair of inguinal hernia.39,40 Level 11-3 evidence suggests that transperitoneal laparoscopic inguinal hernia repair may have an advantage over open inguinal hernia in the ability to detect and simultaneously repair cPPV. The recurrence rate following laparoscopic repair, when compared to open, may also be higher. This is supported by level II-2 data that suggest this may be related to the experience of the surgeon.41,42 The transabdominal extraperitoneal repair has some support for a lower recurrence rate, when compared to the traditional open procedure in using level 11-2 evidence.43,44 In summary, both level I and II-2 data confirm laparoscopy as possessing an ability to diagnose a contralateral PPV or hernia. Defining what may be clinically relevant and warrants treatment is not clear. Similarly, level II-3 evidence is also able to support an overdiagnosis of contralateral pathology in such cases and advocate no such intervention as being necessary. 45 A slightly higher recurrence rate appears to exist when comparing the transperitoneal to the extraperitoneal and open repair. This may be related to surgical experience or the nature of nontransaction of the hernia sac. Reported advantages of a reduced injury to the vas and vessels, a reduction in testicular atrophy, and improved cosmesis are not supported by current levels of evidence.
Expected post-treatment course
Following surgery for inguinal hernia and hydrocele in children, patients are expected to be free from hernia or scrotal swelling. The postoperative course appears to be similar for both open and laparoscopic methods of repair.6–8,39–42 The majority of procedures are performed on an outpatient basis, with an overnight stay reserved for those under 44–50 weeks in conceptual age. 46 The incidence of developing a metachronous hernia following unilateral inguinal hernia is in the region of 6–8%. This approaches 0% if the repair incorporates laparoscopy and a contralateral opening is identified and repaired.39–42,47 Patients can expect to resume normal activity within 48 hours following surgery. 39
Complications and their treatment
Short-term complications are rare following surgery for hernia or hydrocele. Injury to the vas deferens during inguinal or hydrocele repair is a potential risk, 45 with treatment requiring microsurgical repair. Visceral injury during laparoscopic repair is very rare and can be treated either by open or laparoscopic surgery. Injury to the genitofemoral nerve, resulting in chronic pain, is a rare occurrence. 23 Testicular ascent following inguinal tissue contracture is another possible long-term problem as well as testicular atrophy, though the latter is associated usually with preoperative incarceration. Recurrence following inguinal hernia surgery is between 1 and 2% and is usually related to factors such as prematurity, increased abdominal pressure, postoperative wound infection, hematoma, and surgical experience.1–7,21,46 The majority of hernia recurrence is usually evident by 5 years postoperatively. 46 When considering the best approach for recurrent hernia surgery, the open approach can be used for a failed laparoscopic repair and vice versa for a failed open repair. Both afford the advantage of operating in an area without previous scar tissue.
Footnotes
Disclosure Statement
No competing financial interests exist.