Composite Outcomes of Sleep Surgery Using the Modified Sleep Apnea Severity Index (mSASI)

The apnea-hypopnea index (AHI) defines obstructive sleep apnea (OSA) severity but fails to describe nuances in disease burden. The modified sleep apnea severity index (mSASI) combines patient anatomy, weight, sleep study metrics, and symptoms to provide a composite OSA index ranging from 1 to 3. While prior studies have associated mSASI with quality of life and hypertension, its utility in continuous positive pressure intolerant (CPAPi) surgical patients remains unexplored.

A retrospective cohort study of surgically treated CPAPi patients who underwent upper airway stimulation (UAS), maxillomandibular advancement (MMA), or expansion sphincter pharyngoplasty (ESP) at our Tertiary Care Academic Center from 2014 to 2021. Five hundred twenty-eight patients were identified and 260 had available data to calculate mSASI pre- and postoperatively using the published method. Wilcoxon rank-sum tests were used during the analysis.

Out of 260 patients, 167 underwent UAS (64%), 73 ESP (28%), and 20 MMA (8%). Fifty-five percent had a preoperative mSASI = 1 (average = 1.56, standard deviation = 0.68). The average overall change in mSASI postoperatively was -0.32 (p < .01). mSASI change in UAS, ESP, and MMA groups was -0.21, -0.51, and -0.50, respectively. Of note, 64% of UAS patients had a preoperative mSASI = 1, compared to 40% and 37% for MMA and ESP, respectively. The change in mSASI score was not significantly associated with treatment efficacy per Sher's Criteria (p = .6)Conclusion:The mSASI is a valuable alternative index to measure preoperative OSA severity and characterize surgical outcomes. Further prospective studies are needed to confirm these findings and to determine its ability to detect risk reduction post-treatment.

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