A one-arm surgical trial of obstructive sleep apnea (OSA) patients before and 12 months after Bilateral Internal Ramus Distraction of the mandible (BIRD)

BACKGROUND

An innovative approach for the primary and definitive treatment of obstructive sleep apnea (OSA) in adult patients is presented: Bilateral Internal Ramus Distraction of the mandible (BIRD), which is a slow, progressive and more stable procedure to advance the mandibular bone. This study investigated whether this surgical approach is useful to cure OSA.

METHODS

Study design was of an interventional (surgical) one-arm trial of OSA patients assessed before and 12 months after BIRD. All patients were evaluated by pre- and post-operative polysomnography and three-dimensional scans. The amount of skeletal advancement, percentage of upper airway volume increase and postoperative value of mandibular occlusal plane were the predictor variables. Changes in the apnoea-hypopnoea index (AHI), oxygen desaturation index (ODI), and percentage of time with saturation under 90% (TC90) were the main outcome variables.

FINDINGS

Thirty-two subjects with a mean ± SD age of 41.9 ± 13.3 years and 87.5% male were included, and they were followed-up 32 ± 14.2 months. AHI was 47.9 ± 23.1 per hour before surgery and the Epworth Sleepiness Scale (ESS) was 13.4 ± 4.4. Postoperative AHI was 4.8 ± 5.6 per hour 12 months after surgery (P < 0.001), with 81.2% of the patients considered cured (AHI<5) and 18.8% suffering from a mild-to-moderate residual OSA. ESS decreased to 1.9 ± 1.8 at the end of the surgical treatment (P < 0.001). 3D changes revealed an upper airway volume increase of 188.4% ± 73.5% (P < 0.001).

INTERPRETATION

Lengthening the mandibular ramus by distraction osteogenesis to cure OSA appears to be more effective and safer when compared to other surgical protocols, especially in very severe cases with initial AHI>50/h. Titration of the mandibular advancement weekly using respiratory polygraphy allows better healing control and customization of the skeletal advancement, enhancing the aesthetic result.