Surgical intervention to treat a inguinal hernia is a very common pediatric surgical
procedure, often performed using an inguinal incision. Children who undergo hernia repair can
suffer from a significant degree of discomfort postoperatively. A multimodal pain management
approach including medications such as acetaminophen, non-steroidal anti-inflammatory drugs
and opioids have traditionally been used in combination with a regional anesthetic technique.
Regional anesthetic techniques include surgical infiltration of local anesthetic,
caudal-epidural (CE) block or an ilioinguinal/iliohypogastric (IIG/IHG) nerve block.
Regional anesthetic techniques such as CE and ultrasound (US) guided IIG/IHG are
well-established methods shown to reduce the use of intraoperative anesthetics and the need
post operative rescue analgesia. Traditionally, IIG/IHG nerve blocks were completed using a
landmark-based approach but due to unpredictable block results with failure rates over 30%
and potentially serious complications such as unintentional intraperitoneal injection, many
anesthesiologists preferred the more reliable CE technique. However, while the CE provides
excellent intraoperative anesthesia it provides short duration of post-operative analgesia
(4-6 hours) and can be associated with lower limb motor block and urinary retention. Recent
literature has demonstrated that an US guided IIG/IHG can be completed with smaller volume of
local anesthetic with a success rate of up to 100% with low risk of complications.
Furthermore there is evidence to suggest that it provides an increased duration of
postoperative analgesia for pediatric patients undergoing groin surgery. Finally, two
publications retrospectively reviewing complications in over 45000 regional anesthetic blocks
suggest that US guided peripheral nerve blocks (e.g., IIG/IHG) should be favoured over
neuraxial techniques such as epidural and caudal anesthetics due to the risk-benefit profile.
A recent meta-analysis comparing IIG/IIH block to the CE block in children notes that
additional comparative studies are required as previous studies comparing these two
techniques have many methodological limitations including small sample sizes, using blind
(non-US guided) regional anesthetic techniques and grouping patients undergoing various
surgical procedures (e.g., orchiopexy and hernia repair) despite significant differences in
recovery pain profiles.
The investigators are proposing to complete a prospective randomized single-blinded
non-inferiority study to evaluate and compare the effectiveness of an US guided CE block to
an US guided IIG/IHG nerve block in achieving post operative analgesia following a hernia
repair. Currently, a number of Pediatric Anesthesiologists at the Alberta Children's Hospital
do not routinely complete IIG/IIH or CE blocks under ultrasound guidance. As part of this
study investigators hope to provide necessary knowledge (sonoanatomy, technique) and offer
supervised clinical training to anesthesiologists who are interested in participating in the
study. While a hernia repair remains a common procedure, no studies have compared the use of
US guided CE to US guided IIG/IHG. The aim of this study is to establish non-inferiority in
post-operative pain while in hospital as assessed through the Face, Leg, Activity, Cry,
Consolability (FLACC) scale for the US guided IIG/IHG as compared to US guided CE following
hernia repair surgery. Secondary objectives will assess for group differences in need for
rescue analgesia in hospital, analgesia administered at home, and postoperative pain measures
within 24 hours post hospital discharge.
Investigators hypothesize that a US guided IIG/IHG nerve block leads to non-inferior
objectively measured FLACC pain scores (≤ 1 point on FLACC scale) post-operatively while in
hospital relative to an US guided CE block for inguinal hernia surgery.