A Study to Evaluate Changes in Modified Mallampati Class in Patients Undergoing Spine Surgery in Prone Position

Background: Perioperative airway changes due to anesthesia and surgery could change a normal airway at induction to a risky airway at extubation. Objectives: The objective is to evaluate primarily the degree of airway changes, as quantified by the modified Mallampati (MMP) class, after spine surgery in the prone position. Secondary to assess the time required for these changes to revert back to the preoperative state and their correlation with other demographic and surgical variables. Methods: The present prospective observational study was conducted in a tertiary care hospital after ethical approval and trial registration. Fifty ASA I and II patients aged 18-65 years of both sex and undergoing spine surgery in prone positions were included. Supine MMP grade was observed preoperatively and at one, two, four, 24, and 48 hours postoperatively. Statistical analysis: IBM SPSS version 22 (IBM Corp, Armonk, NY) was used.Mean values were compared using paired t-tests and medians by the Wilcoxon test. The Spearman correlation was used to assess a relationship. The time for recovery was analyzed by Kaplan-Meir analysis. Results: An increase in MMP grade was observed at one hour postoperatively in 46 (92%) patients. Changes reverted back in 45 (98%) patients by 24 hours postoperatively. A weak positive correlation with age, weight, body mass index, duration of surgery, perioperative drop in hemoglobin, and a moderate positive correlation with fluid administered and estimated blood loss was recorded. Conclusions: An increase in postoperative MMP occurs in the majority of patients undergoing prone position spine surgery which may persist up to 48 hours. So, more vigilance and caution are warranted should reintubation be needed postoperatively.