Lateral pharyngoplasty: polysomnographic results and phenotype-based analysis of OSA.

Purpose: There are several surgical treatments for obstructive sleep apnea (OSA) including lateral pharyngoplasty (LP) have yielded promising results, clearly improving symptoms of the disease. However, there are few publications in relation to polysomnographic (PSG) results, and patient selection remains a challenge. There are currently four pathophysiological phenotypes for OSA: anatomical, low arousal threshold, ventilatory instability, and poor muscle response. This study sought to evaluate the PSG results of LP and to verify whether the phenotypic profile is predictive of surgical success.

Methods: This was an observational, retrospective, cross-sectional study that analyzed the PSG results (pre-surgical and at least 6 months after surgery) of patients treated with Cahali's LP. To assess phenotypes, the following variables of interest (obtained from the pre-operative PSG) were used: apnea-hypopnea index (AHI) during REM sleep (AHIrem), percentage of hypopneas in the AHI, number of central or mixed apneas, and AHIrem and non-REM AHI ratio.

Results: Of 46 patients, it was possible to evaluate the phenotype in 28 patients. There were significant differences in the AHI values, ranging from 37.5 (20.8-49.7) to 10.3 (2.3-33.0) (p < 0.001). The minimum oxyhemoglobin saturation ranged from 78 ± 11 to 83 ± 8 p = 0.008. The time with oxyhemoglobin saturation < 90% ranged from 3.6 min (0.5-9.1) to 0.0 (0.0-1.5) p = 0.031. An AHIrem of < 20 events/h showed a positive correlation with surgical success.

Conclusion: LP is efficient for the treatment of OSA, yielding significant improvement in all respiratory parameters evaluated by PSG. A pre-operative AHIrem of < 20 events/h was associated with surgical success. Other variables of interest for determining the phenotypes were not predictors of surgical success.