Mechanisms Underlying Improvement in Obstructive Sleep Apnea Syndrome by Uvulopalatopharyngoplasty.

Takahisa Yamamoto,Yoichi Nishimura,Seiichi Nakata,Naoko Fujii,Noboru Iwata

doi:10.1155/2017/2120165

Abstract

In a previous case report, we determined for the first time that uvulopalatopharyngoplasty (UPPP) does not change the volume of the upper airway but causes morphological changes in the entire upper airway. The objective of this study is to elucidate the mechanisms underlying the improvement in obstructive sleep apnea syndrome (OSAS) by UPPP. We present an additional case involving a patient with OSAS treated using UPPP. Morphological and numerical parameter changes after surgery were compared with the corresponding preoperative values. Anatomically accurate upper airway computational models were reconstructed from computed tomographic imaging data. In addition, computed fluid dynamics analysis was performed to reveal inhalation flow characteristics before and after UPPP and clearly assess the effect of UPPP on airflow patterns in the patient's upper airway. An important benefit of UPPP is the morphological changes in the entire upper airway, in addition to widening the restricted area. These morphological changes induce laminarization of the pharyngeal jet. To obtain sufficient efficacy of UPPP in OSAS, the morphological changes in the upper airway and the airflow pattern after the surgery must be controlled.

Highlights

Uvulopalatopharyngoplasty (UPPP) is one of the standard conventional techniques for the treatment of obstructive sleep apnea syndrome (OSAS); it is performed in cases with severe OSAS
This study showed for the first time that UPPP can cause morphological changes in the entire upper airway, without any changes in air volume
Our computational fluid dynamics (CFD) analysis results showed that the benefits of UPPP are inhibition of both the pressure gradient and complex recirculation flow, which laminarizes the pharyngeal jet flow

Summary

Introduction

Uvulopalatopharyngoplasty (UPPP) is one of the standard conventional techniques for the treatment of obstructive sleep apnea syndrome (OSAS); it is performed in cases with severe OSAS. In UPPP, excess tissue in the throat is removed to widen the patient’s airway This procedure may facilitate air movement through the throat more when the patient breathes, thereby reducing the severity of OSAS. Some mechanisms by which UPPP improves OSAS have been suggested These mechanisms remain controversial even though UPPP is a commonly performed procedure for serious cases of OSAS. We had performed morphological analysis in OSAS patients before and after UPPP; it revealed that the upper airway volume hardly changed pre- and postoperatively, 15 g of bilateral tonsil mass was removed [5]. This study used the latest improvements in CFD analysis in conjunction with upper airway scans to characterize the upper airway response to UPPP, using both morphological and numerical parameters. An OSAS patient was selected after reviewing the varied treatment responses of our treated patients, Case Reports in Otolaryngology

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Discussion

Conclusion