Originally published by 2 Minute Medicine^® (view original article). Reused on AccessMedicine with permission.

1. In this pre-/post- cohort study, patients undergoing bariatric surgery had increased airway volumes and a reduction in clinical obstructive sleep apnea diagnoses.

2. Some structures important in mechanical obstruction, such as the soft palate, were unaffected from massive weight loss.

Evidence Rating Level: 3 (Satisfactory)

Obstructive sleep apnea (OSA) is a sleep disorder that can lead to hypoxia and sleep fragmentation due to mechanical obstruction of the airway. One of the leading risk factors of OSA is obesity. Bariatric surgery can provide patients the benefit of assisting them in weight loss, however there is little evidence on the effects of weight loss surgery on OSA. This study aimed to assess post- and pre- surgical weight loss fat content in the pharyngeal area for improving airway space.

This study conducted a pre-/post- cohort study which included patients who underwent weight loss with bariatric surgery, such as sleeve gastrectomy, and had a clinical diagnosis of OSA in Northern Sydney, Australia. Patients were excluded from the study if they had a history of craniofacial abnormalities, non-obesity associated OSA obstructions, or contra-indications to magnetic resonance imaging (MRI). Participants underwent polysomnography to evaluate sleep quality and MRI imaging was conducted for soft tissue analysis at baseline and 6 months after weight-loss surgery.

Overall, this study recruited 18 participants (89% women) with a history of OSA. The cohort had an average weight loss of >30 kg. Furthermore, 40% of individuals no longer classified as having OSA based on polysomnography. Post-MRI images displayed an increase of total air way volume seen in the velopharyngeal region, including a reduction in surrounding intra-tissue fat of multiple structures. There was no significant reduction in soft palate volume. However, this study was limited by its small sample size, its predominant analysis of female participants, and only assessed surgical weight loss as opposed to other commonly applied weight loss mechanisms. Nonetheless, this study was significant in being the first to quantify soft tissue adiposity in upper airway structures following weight loss surgery and evaluating its effect on OSA symptoms.

Click to read the study in Sleep Breathing Physiology and Disorders

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