Effect of Mandibular Set-Back surgery versus Bimaxillary Orthognathic Surgery on pharyngeal airway space and consequent daytime sleepiness in Dento-skeletal class III malocclusion patients.

Abstract

Purpose: Pharyngeal airway space (PAS) assessment after orthognathic surgery is crucial due to the possible resultant breathing hazards. This study compared PAS after mandibular set-back surgery and bimaxillary surgery and its consequent effect on the patients’ daytime sleepiness in class III dento-skeletal patients. Patients and methods Twenty-four patients with dento-skeletal class III deformity were divided equally into two groups; group A underwent mandibular set-back surgery while group B had bimaxillary orthognathic surgery through mandibular set-back and maxillary advancement surgeries. PAS area was measured on lateral cephalometric radiographs. Daytime sleepiness was assessed by Epworth sleepiness scale (ESS). All results were recorded pre-surgically, immediate post-surgically and at 6-months post-surgically. Results In group A patients, the PAS value at T0 (mean of 546.72±66.61 mm2) revealed a non-significant decrease after mandibular set-back surgery at T1 to reach a mean of 542.89±68.65 mm2, which appeared to minimally relapse at T2 to a value still less than T0 (544.00±68.62 mm2) with a final decreased PAS value. In group B patients, the PAS value (mean of 555.05±75.04 mm2) revealed a non-significant increase after bimaxillary surgery at T1 reaching a mean of 555.73±79.34 mm2 which re-increased at T2 to a mean value of 557.79±78.23 mm2. Following the pattern of PAS, the ESS recorded non-significant changes in both groups from the preoperative values to values at T1 and T2. Conclusion Despite of the resulted post-surgical different changes, orthognathic surgery appeared to have no significant effect on PAS area nor on daytime sleepiness in a six-month duration.