Institutional Variability in Anesthesia Time for Mehta Casting in Early-Onset Scoliosis (EOS)

Purpose: Mehta casting is a potentially curative intervention for early-onset scoliosis (EOS) that typically requires multiple anesthetics. The Food and Drug Administration (FDA) reported that >3 hours of anesthesia under the age of 3 years old may alter brain development; however, no standard exists for the duration of anesthesia during casting. The purpose of this study is to quantify the variability in anesthesia during Mehta casting. We hypothesize that significant institutional variability exists and may be attributed to modifiable factors. Methods: An EOS registry was used to identify patients who underwent at least one Mehta casting procedure. Anesthesia exposure was quantified, and site variability was assessed by patient characteristics, cast placement, procedure type, and equipment used. Results:Our cohort consisted of 208 patients from 5 institutions (age 2.6 +/- 1.4 y). There were 1097 Mehta casting procedures, with 5.4 +/- 3.6 castings per patient. Of these patients, 106 (51%) were female, with an average age of 2.11 +/- 1.29 years old at the time casting was initiated. Patient etiologies included 154 idiopathic (74.0%), 22 syndromic (10.6%), 18 congenital (8.7%), 11 neuromuscular (5.3%), and 3 unknown (1.4%). Anesthesia time was 69 +/- 31 minutes and varied significantly between sites (59 +/- 14 to 117 +/- 46 min; P<0.001). Cumulative anesthesia time for patients under 3 years was 320 +/- 197 minutes with 120/161 (74.5%) patients exceeding 3 hours. Anesthesia time was lower after the FDA warning in 2016 compared with pre-2016 (71 +/- 30 vs. 66 +/- 32, P=0.008). Conclusions: Patients undergoing Mehta casting are at significant risk of exceeding 3 hours of anesthesia, which the FDA has stated may be harmful for children <3 years. Significant site variability indicates that standardization protocols should be developed to encourage best practices and minimize anesthetic times.