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Background: Prior studies noted superior analgesic effectiveness of caudal blocks versus ilioinguinal nerve blocks (INB) and a significantly increased risk of motor blockade and urinary retention. The purpose of our study was to compare intraoperative and 1-hour postoperative outcomes in patients who received caudal versus INB for inguinal surgeries.
Methods: We performed a retrospective cohort study of males <10 years of age who underwent inguinal procedures from July 2013-March 2015 using institutional data from the Pediatric Regional Anesthesia Network and Pediatric Health Information System databases and the medical record. We excluded those with a non-caudal regional block, missing/no block or INB following a failed caudal. Nursing staff determined pain scores using the Faces, Limbs, Activity, Crying, Consolability (FLACC) scale (0-10). We compared: intraoperative and post-anesthesia care unit (PACU) morphine equivalents (ME) (mg/kg), intraoperative and PACU narcotic and anti-emetic use (yes/no), maximum pain scores, pre-incision anesthesia time, adjusted operating room (OR) charges to the patient, and block-related complications in patients who received a caudal versus an INB using analysis of variance/Wilcoxon and Chi-square/Fisher’s exact tests as appropriate. We used multivariate logistic and linear regression, controlling for demographics, laterality, procedure type and clustering of similar block techniques by surgeon, to assess the association of block type with the following outcomes: cumulative narcotic use (y/n), maximum pain score, pre-incision anesthesia time, and adjusted OR charges.
Results: 489 patients met inclusion criteria: mean age 3.3 years, 82.3% white, 54.4% public insurance, 60.1% caudal, 78.1% unilateral, 48.3% orchidopexy, 51.7% herniorrhaphy/hydrocelectomy. INB patients were more likely to receive intraoperative narcotics (57.9% vs.17.0%, p<0.0001), received more intraoperative ME’s (median 0mg/kg (interquartile range (IQR) 0,0.01) vs 0 mg/kg (IQR 0,0), p<0.0001) and were more likely to receive PACU narcotics (20.5% vs. 13.6% vs. p=0.04). There was no difference in PACU ME’s (0 mg/kg (IQR 0,0) vs. 0 mg/kg (IQR 0,0), p=0.06) between the two groups. INB patients were more likely to receive intraoperative anti-emetics (71.8% vs. 55.8% vs. p=0.0004). There was no difference in PACU anti-emetics (3.6% vs. 1.7%, p=0.2). INB patients had higher maximum pain scores (2 vs. 0, p<0.0001), shorter pre-incision anesthesia time (21.3 ± 5.9 vs. 27.4 ± 6.5 minutes, p<0.0001) and lower adjusted OR charges ($7,948 ± $808 vs. $8,435 ± 1171, p=0.0006). On multivariate analysis, INB patients had 3.7 times the odds (odds ratio 3.7, 95% CI: 2.2-6.2, p<0.0001) of receiving narcotics, higher maximum pain scores (2.4 ± 2.5 vs. 1.6 ± 2.2, p=0.0004), shorter pre-incision anesthesia time (27.7 vs. 21.8 minutes, p<0.0001) and lower adjusted OR charges ($7,948 ± $808 vs. $8,435 ± 1171, p<0.0001). In the caudal group there were three failed blocks, one abandoned block and one vascular puncture.
Conclusions:
Although maximum pain scores were higher in the INB group than the caudal group, the difference may not be clinically significant. INB block patients had adequate pain control, significantly less pre-incision anesthesia time and lower OR charges. Caudal blocks may offer minimal advantage over INB in the immediate postoperative period. Further prospective studies are needed to examine 24-hour postoperative outcomes.