Inguinal hernia in premature infants

Abstract

The management of inguinal hernia in premature infants is slowly drifting from urgent exploration, surgery before discharge to readmission and elective surgery weighing the balance between risk of incarceration and anesthesia. Advances in neonatal intensive care and improved survival of preterms have resurfaced the issue of dealing with such cases. The advent of miniaturized instruments and better anesthetic agents has established the feasibility and safety of neonatal laparoscopic repair of inguinal hernia. There is an ongoing controversy on whether to operate immediately, just before the neonate is discharged or later on follow up and the safe age to operate on these babies. The paper ‘Management of inguinal hernia in premature infants: 10-year experience. JIAPS.2014; ................... describes the retrospective management of inguinal hernia in preterms over 10-years. The subject remains a source of debate with current practices based on experience and an individualized approach on case to case basis. The timing of inguinal hernia repair in preterms represents a balance of the risks of postoperative respiratory complications and hernia incarceration. At present, the literature does not clearly define what these risks are and how they should be balanced. A preterm is at a greater risk of a multitude of complications and can often require prolonged postnatal intensive care support. Fortunately, over the last three decades, there have been dramatic improvements in neonatal care with decreased level of stress to the neonate. The addition of high frequency ventilation and gentle ventilation with monitoring of blood gases has decreased the level of respiratory distress that often lead to increased abdominal pressures on the underdeveloped inguinal canal with a patent processus vaginalis in the preterm. The decreased frequency of incarceration in the preterms has led to the concept of a more conservative approach with increased waiting period, thus allowing the neonate to tide over the initial crucial period of an immature respiratory system. The hernia sac in older premature infants is tougher, reducing the complication rates after delayed repair. The risk of postoperative apnoea and bradycardia in the premature infant also decrease as the infant matures. The advent of neonatal laparoscopy with documented feasibility and safety has been a major development. Laparoscopic repair in babies weighing more than 3 kg is (theoretically) beneficial in preventing injury (this benefit is theoretical as no-one can prove it) to the vas and is less technically demanding than open inguinal herniotomy (this is a subjective statement and clearly based on individual experience). The term herniotomy is slowly being replaced by the term inguinal hernia repair, as there is usually no division of sac during laparoscopic repair. Most pediatric surgeons doing laparoscopic neonatal hernia repair prefer to wait till the baby gains adequate weight (size is clearly a technical issue due to a safe working domain but is generally feasible above 2 kg). There have been anecdotal cases of incarceration during this waiting period and this has further emphasized the fact that waiting is not detrimental for the neonate. This also prevents the risk of anesthetic drugs on a premature renal and hepatic system. Reducing the incarcerated hernia and performing an elective procedure after 3 days reduces the morbidity from 10-20% to 1-2%. The incidence of bilateral hernia is increased in preterms. Waiting for an adequate period allows appropriate diagnosis for the presence of a contralateral patent processus vaginalis, especially if open procedure is planned. Babies at increased risk of developing a bilateral inguinal hernia, include those with cystic fibrosis, urological anomalies involving pubic diastasis, congenital dislocation of hip, abdominal wall defects, connective tissue disorders, ventriculoperitoneal shunt, peritoneal dialysis and ascites. In boys, there is usually a patent processus vaginalis associated with an undescended testis. Performing an open herniotomy through an inguinal incision in a premature with an undescended testis may reduce the chances of a natural descent till 1 year of age due to the scaring and handling of the spermatic cord structures, apart from the risk of injury to the delicate vas. Figure 1 outlines a proposed algorithm based on recent trends in management incorporating the practices at two different centres of the world are discussed. The risks and benefits of each option should be discussed with the family to help them make a decision. Figure 1 Algorithm incorporating various options in management of inguinal hernia in the premature infant (*Preferred approach)