Introduction

Inguinal hernia (IH) is an extremely common disorder of childhood that necessitates surgical repair at diagnosis [1]. Its incidence is variously reported as 0.5% to 14% [2]. By projecting this upon the 363 million pediatric population of India [3], it is roughly estimated that every year, 4 to 6 lakhs children must have been undergoing inguinal hernia repair (IHR) in the Indian subcontinent. Therefore, a practicing pediatrician is likely to see, on an average, one or two cases every week. Parents often prefer to discuss their concerns with primary care physicians rather than surgeons. Prior to 1990s, pre-operation counseling was relatively easy because all IH were repaired by a standard groin-incision technique. However, with the advent of laparoscopic surgery it became difficult to keep track of the newly introduced surgical techniques and their relative ‘merits and demerits’. The scenario is further complicated by free availability of medical information through internet, improved public awareness, utopian desire of every parent to give their child the choicest of the best, growing intolerance of even minor adverse events and an increasingly litigious society. Therefore, accurate and evidence-based counseling is essential to avoid parental dissatisfaction and legal disputes. This review is intended to provide pediatricians with scientific information as to the best method of repairing pediatric IH.

General Comparison of Available Options

The basic aim of all IHRs is to prevent protrusion of abdominal viscera by obliterating the hernial sac. In adults, as the hernial sac is acquired due to weakness of abdominal musculatures, prosthetic mesh reinforcement (hernioplasty) is invariably required for radical cure. Contrarily, as pediatric IH is due to congenital patency of processus vaginalis, surgical disconnection of the sac (herniotomy) is sufficient. This principal difference prohibits drawing of pediatric inferences from adult literature.

Pediatric IH is conventionally repaired by open herniotomy (OH) in which the hernial sac is dissected off the cord structures and divided at the level of the deep ring through a 2 to 3 cm- long inguinal incision. Technical variations of OH are fewer (Table 1), rarely practiced and they do not differ significantly in their outcome [4].

Table 1 Technical variations of open herniotomy
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Laparoscopic herniotomy (LH) is classically done by 3-port technique in which the optical telescope (representing the surgeon’s eyes) is inserted through the central port and working instruments (representing the surgeon’s two arms) are inserted on either side of it. Suturing the neck of hernial sac rather than its complete excision is typical of LH (Fig. 1a, b). In contrast to OH, technical variations are plenty in laparoscopy (Table 2). Reducing the number of access ports, method of dealing with the neck of hernial sac and the technique of suturing are the principal themes of modifications. Quite dissimilar to OH, technical modifications of LH significantly differ in their outcome. For example, repair integrity is better with Dissection-Division-Suturing (DDS) of the neck of hernial sac than with other techniques [5]. Recurrences are fewer with linear suturing of deep ring than with purse-string closure [6]. Non-absorbable sutures give better long-term cure than absorbable materials [7]. However, the final outcome was not dependant on the number of access ports [8]. Further, LH in general, and each of its variations in particular, have a definite learning curve [9]. Therefore, outcome of LH varies not only with different techniques but also according to the level of surgeon’s experience.

Fig. 1
figure 1

Laparoscopic hernia repair. a Endoscopic view of hernial orifice (Neck of sac). Note that vas and vessels are divergent and not closely associated as they would be in spermatic cord. b Hernial orifice occluded by intraperitoneal suturing

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Table 2 Technical variations of laparoscopic herniotomy
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Comparison of Outcome Parameters

Owing to its technical simplicity, high success and low complication rates Ferguson’s OH is widely considered as the Gold Standard against which all other techniques are evaluated. Several parameters [10] have been suggested for comparative assessment of outcome (Table 3). Superiority of a technique is sometimes claimed on the basis of logical extrapolations and hypothetical assumptions. Conclusions of randomized controlled trials (RCT) and meta-analyses simply demonstrate statistical superiority while critical appraisal is essential to infer clinical relevance [11].

Table 3 Outcome parameters of inguinal hernia repairs
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Operation Time

In bilateral lesions, LH is consistently found to be quicker than OH [12,13,14]. This is because laparoscopy saves time by utilizing the same set of ports to repair both sides whereas OH requires separate incisions for each side. Unlike in OH, layers of abdominal wall are not sutured in LH. Probably this compensates the initial time spent in establishing laparoscopic pneumoperitoneum. In contrast to bilateral hernia there is no consensus in unilateral cases. Duration of LH is variously concluded in different meta-analyses as longer [12], similar [13] or shorter [14] than OH. This suggests that operation time is determined more by dexterity of surgeons rather than by surgical techniques. The reported mean difference of 5 to 15 min between OH and LH may be statistically significant; but it is of no practical importance.

Collateral Injury to Adjacent Structures

IHR involves dissection of hernial sac from the vas deferens and testicular vessels. Therefore, in every hernia repair, iatrogenic injury to these structures is a theoretical risk. Vas injury is reported in 0.13% to 0.5% of pediatric herniotomies [15] and it is responsible for 6.6% of male infertility [16]. In LH, dissection of hernial sac is altogether avoided by suturing the neck of sac. Even in DDS technique of LH, dissections are minimal and are done at internal ring level where the vas and vessels are divergent. Further, optical magnification of laparoscope is hypothesized to reduce operative injury. However, actual clinical data in support of these assumptions are extremely scarce. In adults undergoing bilateral hernia repair, obstructive azoospermia was noted in 0.03% of open repairs and 2.5% of laparoscopic procedures [17]. In a small retrospective series, intraoperative vas injury was recognized in 7% of LH as compared to 0% in OH [18]. Nevertheless, unilateral injury to the vas deferens is extremely difficult to recognize as it remains asymptomatic and is well compensated by contralateral spermatogenesis. None of the RCTs comparing LH with OH has sufficient sample size to assess true risk of vas injury.

Ischemic atrophy of testis has been reported in 0.5% to 5.8% of boys undergoing herniotomy [19]. Atrophy rate goes as high as 10% in incarcerated hernias. Recent studies have shown that both OH and LH do not significantly alter testicular perfusion although it is transiently impaired in OH [20, 21].

Chronic groin pain, reported in 5% to 13% of OH, is attributed to operative disruption or suture entrapment of groin nerves [22]. LH is expected to avoid nerve injury as it approaches the hernial sac from peritoneal surface. Electrophysiological studies have indeed confirmed that conductivity of genitofemoral nerve is significantly better with LH than with OH [23]. However, practical implications of this observation are yet to be established. Interestingly, deliberate prophylactic neurectomy of inguinal nerves is recommended in adults to avoid chronic groin pain [24].

Post-operative Pain

Laparoscopy, being a minimally invasive procedure, is generally expected to cause less pain and hence less analgesic requirement. Three single-blind RCTs reached contradicting conclusions. A Chinese study [25] confirmed that LH is less painful; while a Finnish RCT found it actually more painful than OH [26]. Increased pain of laparoscopy is thought to be due to stretching of peritoneum by CO2 pneumoperitoneum. Another RCT from Turkey found that pain scores and analgesic requirement were not statistically different between LH and OH [27]. One meta-analysis [13] concluded that postoperative pain in LH is comparable to that of OH while another meta-analysis [12] found the evidences insufficient to make any firm conclusion. These contradictory results can be explained by the practical problem of quantifying pain. Being a subjective sensation, children often find it difficult to accurately express their pain. Further, patient bias and observer bias could not excluded in the absence of a well designed double-blind RCT.

Noteworthily, shoulder pain which is seen in 5% to 17% of LH patients has never been reported in OH [26, 27]. As this referred pain is attributed to phrenic nerve irritation caused by pneumoperitoneum, it is an exclusive complication of LH. Intraperitoneal instillation of local anesthetics at the conclusion of laparoscopy is suggested to reduce shoulder pain.

Immediate Post-operative Complications

Unlike OH extensive tissue dissection is not done in LH. Therefore dissection-related complications such as hematoma, wound infection and scrotal edema are expected to be lesser with LH [14]. Pooled data of a systematic review suggested that these complications occur in 0.9% of LH as against 2.7% of OH [28]. However, a meta-analysis did not find any significant difference in the complication rate of LH and OH [13]. This discrepancy is probably due to reporting bias and selection bias.

Recurrence

Recurrence after surgical repair of hernia may be of two types: ipsilateral recurrences (ILR) indicate failure of repair while contralateral recurrences (CLR) are de novo lesions of the opposite side. In published literature, the term ‘recurrence’ has often been confusingly used to denote both of them.

Initially, LH was apprehended to have more ILR as the sac is simply ligated rather than excised. Reported incidence of ILR is 0% to 6% in OH and 0% to 5.5% in LH. Pooled data of 11,142 patients [28] and a meta-analysis [13] confirmed that a mean ILR rate of 1.4% is identical between the two groups. Correlation between ipsilateral recurrence and various techniques of LH is well known (vide supra). Prematurity, age less than 1 y, obstructed hernia and presence of co-morbidities may also increase ILR as high as 15% in both the groups [29, 30].

In unilateral hernias the chances of having a patent sac on the opposite side is as high as 50% [31]. Several decades ago pediatric surgeons routinely performed bilateral exploration in unilateral hernias. However, only 7% of such children developed contralateral hernia implying that all patent sacs need not necessarily become clinical hernia [32, 33]. Therefore the routine practice of contralateral exploration has been given up in open surgery. Introduction of laparoscopy rekindled the interest in contralateral patent sac [34]. Laparoscopy enables examination and suturing of contralateral sac without the need for any additional incision. Indeed, studies have shown that routine prophylactic suturing of contralateral sac reduces metachronous hernia from 7% to 0.3% [29, 35]. This approach required ligation of 4 to 6 sacs to prevent one future hernia [35]. Thus a vast majority of children underwent needless intervention. Further, negative laparoscopy did not completely eliminate the risk of future CLR. It is found to occur in 1% to 3% within 3 mo to 5 y of negative laparoscopy [36, 37]. Incidence of CLR is proportionate to the length of follow-up. Several studies quoting a low rate of CLR with LH suffer from insufficient follow-up. Routine bilateral intervention increases the operation time and thereby, substantially increases the cost of care [38].

Hospital Stay

Pediatric herniotomy is usually done as a day-care surgery. Therefore, the benefit of shorter hospital stay that is typical of laparoscopy is not expected in LH. Although an RCT [26] reported that LH needed prolonged hospital stay than OH (5 h vs. 3.8 h), this difference is of no practical significance. Recent meta-analysis [13] affirmed that there is no significant difference in the duration of hospital stay between the two procedures.

Time to Resume Full Activity

In both LH and OH children resume normal activities within 2.5 d [26]. A meta-analysis also confirmed that there is no significant difference between the procedures [13]. This could be a corollary to the fact that OH and LH do not differ significantly in post-operative pain score.

Cost of Treatment

Laparoscopy requires costly instruments and general anesthesia. Hence the cost of LH is 2 to 3-fold higher than that of OH [39]. It is not known whether this high cost is justified in terms of improved quality of life in pediatric age group. Unlike other laparoscopic surgeries the high instrument cost of LH is not compensated by shorter hospital stay in pediatric IHR.

Cosmesis and Parental Satisfaction

Cosmetic results of LH are slightly better than that of OH in the early post-operative period. Unsightly scars were noted in 4% of OH while none in LH [40]. However this difference tends to fade away with passage of time as scars mature and flatten. An RCT found that cosmetic score of LH is better than that of OH in bilateral hernia but not in unilateral cases [27]. Another RCT found that parental satisfaction scores of OH and LH were no different at 2 y of repair [26]. It is also pointed out that cosmetic emphasis is unimportant, given the location of OH scar which is well concealed even by swim suits (Fig. 2) [11].

Fig. 2
figure 2

Scar cosmesis of herniotomy (a) shows two inguinal scars (arrows) of bilateral hernia repair. As early as 6 mo after surgery they are camouflaged by the skin crease and are very well below the swim-suite line. Over subsequent years the scars are expected to further flatten-out and become barely visible (b) shows two working-port scars (arrows) of laparoscopic unilateral hernia repair. (Scar of telescopic port has merged with umbilical folds) Even after 8 y of repair they are prominently visible above the waist line (Figure 2b courtesy of Prof. Y. K. Sarin, New Delhi)

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Procedure Specific Complications

In LH, as the sac is simply ligated rather than being excised, exudates trapped inside the distal sac were apprehended to cause hydrocele. The reported incidence of hydrocele is 0.2% to 5.7% in LH as compared to 2.9% to 6.6% in OH [28]. However a meta-analysis found this difference statistically insignificant. Further, such hydroceles are noted to resolve spontaneously within 3 wk [40].

Testicular displacement during open dissection was thought to cause post-operative ascend of testis (iatrogenic cryptorchidism). LH, which altogether avoids handling testis is expected to annihilate this complication [41]. Surprisingly, it is reported to occur in 0% to 5.9% of LH while only 1.7% to 3.2% in OH [28]. A recent study even suggested that tissue adhesions formed between cord structure and inguinal canal in OH is actually protective while the intact smooth sac left behind in LH facilitates upward migration of testis [42]. However, a meta-analysis found no significant difference between the groups [13].

Visualization of internal ring in LH confirms the patency of sac and hence the mistake of operating on wrong side is unlikely in LH. However, hard data to support this assumption is lacking.

Anesthesia Related Concerns

Unlike OH which can be done under regional or local anesthesia, LH invariably requires general anesthesia. The later is widely acknowledged to be riskier than the former especially in preterm infants and in the presence of cardio-respiratory disorders. General anesthesia also increases the risk of post-operative apnea, prolongs recovery time and escalates cost of care. Drugs used in inhalation anesthesia are now thought to adversely affect the developing brain.

Pneumoperitoneum of laparoscopy, not only impedes venous return by increasing intrabdominal pressure but also leads to acidosis by absorption of carbon dioxide. A recent study has shown that these factors really affect brain oxygenation during LH [43]. Fortunately, the changes are quickly compensated by homeostatic adaptive mechanism.

Surgeon’s Learning Curve

LH is associated with a definite learning curve which is much longer than OH [44]. Consultants required 13 operations while residents needed 30 operations to learn the proper technique [9]. It is really not known if surgeons with sub-optimal exposure compromise patient safety.

Comparison of Specific Situations

Unilateral vs. Bilateral

Bilateral LH has been acknowledged to be better than OH or unilateral LH in terms of shorter operation time and short-term cosmetic results [14]. Even in unilateral hernias routine prophylactic repair of opposite side sac may be theoretically advantageous [34].

Infants and Neonates vs. Older Children

Post-operative apnea and carbon dioxide pneumoperitoneum of LH were initially considered harmful to neonates and premature infants. Several studies attested the safety of laparoscopy in these vulnerable infants [45, 46]. It is even suggested that in neonates LH is technically less demanding than OH as it avoids any dissection of sac [47]. However, post-operative complications were 5.5% in term babies while it increased to 20% in preterm infants [48]. Similarly, serious respiratory compromise following LH occurred in 5% of premature babies as against only 1.5% of term newborn [48]. This raises serious concerns against LH in premature babies.

Male vs. Female

Although the trouble of dissecting vas and vessels is circumvented in LH, purse-string suture sans dissection is feared to cause kinking of vas. However in practice, vas injury of OH and LH are identical (vide supra). In females, often a loop of fallopian tube is found adherent to hernial sac. Unintentional ligation of fallopian tube is predicted to be less likely with LH because the internal anatomy is well visualized before ligation of sac [49]. Rarely androgen insensitivity (male pseudohermaphroditism) may present with female phenotype and bilateral inguinal hernia. In such patients laparoscopy offers the advantage of easy inspection of pelvic organs to confirm absence of uterus.

Giant vs. Regular Size Hernia

Huge hernial sacs involve extensive dissection in OH and hence are associated with increased risk of hematoma, scrotal edema and injury to adjacent structures. Laparoscopic suturing of internal ring without any attempt to dissect the sac is expected to minimize these complications [50]. However, large hernias post enormous technical challenges during LH so that 6% of the procedures have to be converted to OH [50].

Emergency vs. Elective Herniotomy

Edematous hard structures of obstructed hernia are highly vulnerable for operative injuries during emergency repair. LH is considered to be advantageous as it avoids dissection of vas and vessels [51]. In a small series, serious complications were noted in 8% of emergency OH as compared to 1.6% with emergency LH [52]. Further, LH facilitates reduction of strangulated intestine by widening the internal ring and also helps in confirming the viability of reduced bowel. Contrarily, distended or gangrenous bowel may pose technical limitations to LH. An English study found that both OH and LH are of comparable results in emergency settings [52].

Presence vs. Absence of Co-morbidity

Anecdotal observations suggest that LH is advantageous in the presence of co-morbidities such as obesity, ambiguous genitalia and multiple hernias which occur in 0.1% of pediatric inguinal hernias. On the other hand LH may be potentially detrimental in co-morbidities such as congenital heart diseases, respiratory problems and connective tissue disorders. In hernias associated with undescended testis a combined repair of both using a laparoscope is probably comparable to that of open surgery [53].

Recurrent vs. Virgin Hernia

Adhesions of previous operation pose great technical hindrance during re-operation for ipsilateral recurrence [54, 55]. In such a scenario, surgical approach avoiding previous route is desirable. Therefore recurrence after LH is better repaired by OH and vice versa [56].

Concluding Recommendations

An international survey of pediatric surgeons found that OH is often preferred than LH [57]. In the absence of clear superiority of one procedure over the other, the choice of repair should be left to preferences of parents and treating surgeon. Decision making is facilitated by clearly defining criteria of unacceptable results (Table 3). Hospital stay more than 1 d (2 nights), any death attributable to hernia repair, re-admission within 30 d for complications or re-operation within 1 y for recurrence should be considered unacceptable with either OH or LH [10]. After carefully weighing of current evidences authors’ recommendation as to choice of pediatric hernia repair is summarized in Table 4.

Table 4 Authors’ recommendations on the choice of pediatric herniotomy
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