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Journal of Pediatric Surgery (2011) 46, 908–911

Prematurity, not age at operation or incarceration, impactscomplication rates of inguinal hernia repairRobert Baird, Suad Gholoum, Jean-Martin Laberge, Pramod Puligandla⁎

Division of Pediatric General Surgery, The Montreal Children's Hospital, McGill University, Montreal, Quebec,Canada H3H 1P3

Received 21 February 2011; accepted 21 February 2011

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Key words:Inguinal hernia;Complications;Incarceration;Infant

AbstractPurpose: Inguinal hernia repair (IHR) remains the most common procedure in pediatric surgery.Although postoperative sequelae are well described, we examined if prematurity and age were importantdeterminants of postoperative complications.Methods: A retrospective review of children younger than 2 years undergoing IHR from 2004 to 2007was performed, with a minimum of 1-year follow-up. Patients were segregated into groups based on ageat diagnosis (A, 0-3; B: 4-26; C: 27-52; D: 53-104 weeks), with or without prematurity. Incarcerationrates were investigated. Complications were categorized as major (vas injury, recurrence, testicularatrophy) or minor (wound infection, “high” testicle, hydrocele) and compared.Results: Two hundred sixty-eight patients were analyzed (98 premature), with 14 major complications(5.2%) and 26 (9.7%) minor complications overall. Groups A and B accounted for more major (12/14)and minor complications (22/26) when compared with groups C and D (P b .005). In patients less than26 weeks (groups A and B), premature infants had more complications than term infants (27.7% vs12.1%, P = .01). Of 22 patients with incarcerated hernias, 2 (9.1%) had major complications (P b .5 vsnonincarcerated patients).Conclusions: Our study suggests that prematurity, rather than age at operation or incarceration, affectscomplication rates after IHR. This information should be used to frame the discussion of informedconsent for this commonly performed procedure.© 2011 Elsevier Inc. All rights reserved.

Inguinal hernia repair (IHR) is the most commonoperation performed by pediatric surgeons and is generallyassociated with a very acceptable adverse event profile.Complications of pediatric IHR have been well documentedin large reviews [1,2], and it has been demonstratedpreviously that prematurity is an independent risk factor

⁎ Corresponding author. Tel.: +1 514 412 4438(office); fax: +1 514 412289.E-mail address: pramod.puligandla@mcgill.ca (P. Puligandla).

022-3468/$ – see front matter © 2011 Elsevier Inc. All rights reserved.oi:10.1016/j.jpedsurg.2011.02.059

for postoperative recurrence [3,4]. Nonetheless, the riskfactors associated with all complications have not beenrigorously described in a contemporary cohort. Furthermore,chronological age at the time of operation has not beenpreviously evaluated as a possible risk factor for postoper-ative complication. The purpose of this study was to evaluateour institutional adverse event profile with pediatric inguinalhernia repair in patients younger than 24 months and toassess whether prematurity, timing of repair, or urgency ofrepair affected the risk of postoperative complications.

Table 1 Demographics of patients younger than 24 mundergoing IHR from 2004 to 2007 (n = 268)

Sex (female-male) 23:243No. of premature patients 98 (36.6%)Mean age at repair (wk) 29.3No. of patients with ≥1 comorbidity 91Side of hernia (right/left/bilateral) 127/87/54

909Prematurity impacts complication of inguinal hernia repair

1. Patients and methods

Research ethics board approval was obtained for this studythrough the office of the Director of Professional Services atour institution. The study was performed as a retrospectivereview of the records of all children younger than 24 monthswho were diagnosed with an inguinal hernia at the MontrealChildren's Hospital from 2004 to 2007. The MontrealChildren's Hospital is a moderate-sized tertiary careacademic hospital with a university affiliation. It is a trainingcenter for surgical residents and pediatric surgery fellowswho perform all procedures under direct staff supervision. Ingeneral, surgical trainees participated in the cases of patientsolder than 1 year and performed a classic high ligation of thesac after opening the inguinal canal. Procedures performed inpatients younger than 1 year were performed by the surgicalfellow. In these procedures, the sac was frequently mobilizedthrough the external ring without opening the inguinal canal(Mitchell-Banks technique). Occasionally, a Clatworthytechnique was required for extremely thin sacs that weredifficult to control. In this technique, the hernia sac would besequentially dissected from the cord structures until the entirehernia sac was isolated with a series of hemostat clamps.During the study period, the pediatric surgical serviceconsisted of 5 practicing surgeons, with no significantvariation in technique. There were no laparoscopic proce-dures or reoperations performed in our cohort.

We excluded all patients initially diagnosed with ahydrocele and who were subsequently found to have ahernia at the time of surgical repair. Patients were evaluatedas being either term or premature based on birth before orafter 37 weeks of gestational age, respectively. Patients weredivided into 4 groups and were analyzed according to theirchronologic, uncorrected age at diagnosis (A, 0-3; B, 4-26;C, 27-52; D, 53-104 weeks). Incarceration was defined asthe need for the administration of intravenous sedation(ketamine, fentanyl, morphine) to achieve hernia reduction.An emergency procedure was defined as any procedure thatwas not scheduled on a surgeon's elective operative list. Wealso independently evaluated patients who were operated onemergently for IHR without achieving preoperative reduc-tion. Patients were followed up for a minimum of 1 year afterrepair for evidence of postoperative complications. Majorcomplications included the development of recurrence,injury to the vas deferens, and testicular atrophy. Othercomplications were also sought (bladder, bowel injury). Theminor complications reported included wound infection andpostoperative hydrocele. The development of a high testiclewas reported as a minor complication, although the need fororchidopexy was not.

Statistical analyses were first performed by comparingage groups within the term/preterm distinction. Comparativeanalyses were then carried out for infants of similarchronological age groups who were either term or preterm.An independent analysis of incarcerated hernias andemergency procedures was also performed within our

study cohort. Statistical significance of the data wasdetermined by using a 2-tailed Fisher's Exact test fordichotomous variables, with P b .05 considered significant.

2. Results

Two hundred sixty-eight children met the inclusioncriteria for evaluation during our study period, of whom176 were term and 98 (36.6%) were premature (Table 1).Sixty-nine premature patients (70%) had associated comor-bidities, whereas 34 term patients (19.3%) had an associatedcomorbidity. In both cases, the most common comorbidityinvolved the respiratory system (bronchopulmonary dyspla-sia, apnea of prematurity). Eighty percent of hernias wereunilateral. Thirty-nine procedures (14.6%) were performedon an emergency basis. Overall, there were 14 majorcomplications (5.2%) and 26 (9.7%) minor complicationsassociated with IHR, with no documented complicationsassociated with anesthesia.

Table 2 summarizes all of the complications that occurredin term infants within our study cohort. Twenty-six repairswere performed on an emergent basis. There were 8 majorcomplications (4.7%), chiefly recurrences, 9 minor compli-cations (5.3%) but no documented injury to bladder orbowel. Two minor complications occurred in childrenundergoing emergency IHR, but there was no significantdifference in the rate of complications when comparingyounger (groups A and B) vs older (groups C and D) patients(12.1% vs 7.5%, P = .44) within the term cohort.

Table 3 summarizes the complications that occurredwithin the preterm cohort. Thirteen IHRs were performed onan emergent basis. There were 6 major complications (6.1%)and 17 minor complications (18.9%), chiefly postoperativehydrocele formation. We also identified significantly morecomplications when comparing younger (groups A and B) vsolder (groups C and D) patients (27.4% vs 0%, respectively;P N .001) within the preterm cohort.

A comparison of age groups between term vs pretermpatient cohorts revealed that premature infants younger than26 weeks (groups A and B) had significantly morecomplications than term infants of the same chronologicalage (23 [27.7%] vs 11 [12.1%], P = .01). Of the 22 patientswith incarcerated hernias, 2 (9.1%) had major complications,whereas 5(22.7%) had minor complications. These rates didnot differ significantly when compared with patients without

Table 2 Postoperative complications of IHR among term infants

Group A (0-3 wk)(n = 20)

B (4-26 wk)(n = 70)

C (27-52 wk)(n = 19)

D (53-104 wk)(n = 61)

Total (%)(n = 170)

Major complications 8 (4.7%)Recurrent hernia 1 5 0 1 7 (4.1%)Testicular atrophy 0 0 0 0 0Injury to vas deferens 0 0 0 1 1 (0.6%)Minor complications 9 (5.3%)Hydrocele 1 1 1 2 5 (2.9%)Wound infection 1{1} 2 0 0 3 (1.8%)“High” testicle 0 0 1{1} 0 1 (0.6%)

Total (%) 3 (15%) 8 (11.3%) 2 (10.5%) 4 (6.6%) 17 (10%)

Twenty-six procedures were performed on an emergent basis in this cohort.{} indicate complication ensued from a procedure performed on an emergent basis.

910 R. Baird et al.

incarceration (P b .5). Emergency vs elective operation wasalso not found to predict complication rates, within thecohort as a whole (17.9% vs 14.4%, P = .63), in term patients(8.3% vs 11.6%, P = 1.0), or in premature patients (38.5% vs21.2%, P = .18). Two patients were operated on emergentlyfor IHR without achieving preoperative reduction, one ofwhich developed a hydrocele that resolved spontaneously.

None of the inguinal hernia recurrences occurred inpatients who underwent an emergency IHR for incarceration,although 3 of the 10 recurrences occurred in prematureinfants. All episodes of postoperative hydrocele resolvedwithout surgical intervention. Of the 3 patients whodeveloped a postoperative wound infection, all weremanaged with antibiotics alone on an outpatient basis.None of these infections occurred in a patient withincarcerated hernia, but infections did occur in youngerpatients (groups A or B). We identified 2 premature infantswho had injury to the vas deferens, one of which underwentemergency repair of an incarcerated hernia.

3. Discussion

Pediatric IHR is generally considered the most commonlyperformed procedure by practicing surgeons. Complications

Table 3 Postoperative complications of IHR among preterm infants

Group A (0-3 wk)(n = 18)

B (4-26 wk)(n = 66)

Major complicationRecurrent hernia 1 2Testicular atrophy 0 1{1}Injury to vas deferens 0 2{1}Minor complicationHydrocele 3{3} 10Wound infection 0 0“High” testicle 1 3

Total (%) 5 (27.8%) 18 (27.3%)

Thirteen procedures were performed on an emergent basis in this cohort.

after IHR occur in 1.7% to 8% of all cases, although thesestudies vary in their reporting of “minor complications” andgenerally include pediatric patients of all ages [5-7]. Our5.2% rate of major complications appears similar to ratesreported in the literature, whereas our overall complicationrate of 14.9% exceeds these. However, limiting ourinvestigation to patients younger than 2 years inherentlyselects patients at higher risk of complications. Indeed,previous reports have demonstrated increasing rates ofcomplications with decreasing patient age [8,9], and a recentreview of patients less than 5 kg in weight demonstrated anearly identical (14.4%) overall complication rate to thatpresented here [10].

Over one third of our total study cohort (36.6%) waspremature. We demonstrated that prematurity increased theoverall risk of a postoperative complication in the subset ofpatients younger than 6 months. Furthermore, if we excludedhernia recurrence from our data of major complications, wenoted 3 significant injuries to reproductive structures in ourpremature population, as opposed to none in term infants.This contradicts the findings of Moss et al who reported a2.3% complication rate in IHR performed in infants youngerthan 2 months. They found that prematurity was not a riskfactor for the development of complications (2.6% vs 2.2%)[11]. We hypothesize that the extreme friability of the

C (27-52 wk)(n = 27)

D (53-104 wk)(n = 7)

Total (%)(n = 98)

6 (6.1%)0 0 3 (3.1%)0 0 1 (1%)0 0 2 (2%)

17 (17.4%)0 0 13 (13.3%)0 0 00 0 4 (4.1%)0 0 23 (23.5%)

911Prematurity impacts complication of inguinal hernia repair

premature hernia sac, coupled with an increased frequency ofconcurrent medical problems in this population, renders IHRmore technically demanding, and, therefore, at a higher riskfor the development of a postoperative complication. We,therefore, advocate IHR in premature infants after thestabilization of significant comorbidities and dischargeplanning has begun, provided no episodes of incarcerationhave been documented. This period of stabilization typicallyresults in premature infants being operated on closer to term.

Our study demonstrated no difference in complicationrates between emergent and elective cases. This findingdiffers from previous reports documenting an increase inmajor complications in patients undergoing repair for anincarcerated hernia [12,13]. Although our data did not reachstatistical significance, we postulate that our sample size waslikely underpowered to detect this difference. This seemsparticularly true in the group of premature patients requiringemergent operation because the difference in complicationrates (38.5% vs 21.2%) appeared clinically significant.Furthermore, only 2 patients went directly to emergentoperative repair without achieving hernia reduction, suggest-ing that the reduction of incarcerated hernias with pharma-cologic adjuncts is usually achievable. This highlights animportant caveat that needs to be considered when appraisingprevious reports on this subject: the lack of a consistentdefinition of incarceration. Most “irreducible” hernias can bereduced by an experienced hand with or without pharma-ceutical adjuncts. We have previously demonstrated animportant disparity in the “true” vs the “reported” incarcer-ation rates based on a clinically relevant definition [14].

There are several important limitations to consider inevaluating the data generated by our study. Because thestudy is retrospective in nature, data collected were notexpressly generated for research and are, therefore, subject toall of the inherent biases of such methodology. Relative toseveral other investigations of pediatric IHR, this study issmall and derived from a single institution; the potential fortype-II error exists, particularly with regard to complicationsin urgent/incarcerated cases. Our minimum follow-up time of1 year is adequate for the assessment of all complicationswith the important exception of recurrence. Grosfeld et al[15] noted only 50% of recurrences by 6 months, and 96% by5 years, suggesting further follow-up is necessary to

accurately report this parameter. However, our practice isfor routine surveillance 1 year after operation with furtherfollow-up on an as-needed basis only.

Because of the extreme regularity with which pediatricIHR is performed, the minimization of complications is ofparticular importance to the practicing pediatric surgeon. Ourstudy suggests that prematurity, rather than age at operationor incarceration, affects complication rates after IHR. Thisinformation should be used to frame the discussion ofinformed consent for this procedure.

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