Evaluation of OSA treatment outcomes
To each patient of both groups, the home sleep apnea study (HSAT) performed before either surgery or CPAP treatment were re-examined and all respiratory data collected. In the TORS group the post-treatment respiratory outcomes were collected to the HSAT performed at the last follow-up. In the CPAP group the respiratory outcomes were extracted from an HSAT performed simultaneously with the last control of the device (at least 6 months after CPAP activation).
In all cases the sleep studies were performed in an unattended way by means of a Polymesam Unattended 8-channel Device. The following parameters were recorded during the sleep study: respiratory movement and airflow, heart rate, arterial oxygen saturation, position of patient and sleep time.
The apnea-hypopnea index (AHI), Oxygen Desaturation Index (ODI), and the lowest SpO2 (LOS) were collected and recorded by experts in sleep medicine according to the American Academy of Sleep Medicine (AASM) guidelines [42].
Delta AHI (postoperative AHI minus preoperative AHI), Delta ODI (postoperative ODI minus preoperative ODI) and Delta LOS (postoperative LOS minus preoperative LOS) were calculated in order to express the value of surgical efficacy and to compare the two groups of patients. Therapeutic success was defined, in according to the existing literature (Sher’s criteria), as the achievement of a postoperative value of AHI < 20 and a 50% improvement in the preoperative AHI value (18).
Patients with incomplete HSAT data or recent treated cases (post-treatment HSAT evaluation shorter than 6 months) were excluded to the study.