title: Volumetric MRI analysis pre- and post-Transoral robotic surgery for obstructive sleep apnea.
abstract: OBJECTIVE
  To quantitatively measure volumetric changes in upper airway soft tissue structures using magnetic resonance imaging (MRI) pre- and post transoral robotic surgery for obstructive sleep apnea (OSA-TORS).
  
  
  METHODS
  Prospective, nonrandomized, institutional board-approved study.
  
  
  METHODS
  Apneics undergoing OSA-TORS, which included bilateral posterior hemiglossectomy with limited pharyngectomy and uvulopalatopharyngoplasty, had upper airway MRIs pre- and postoperatively. Changes (percent and absolute values) in upper airway and surrounding soft tissue volumes were calculated. We assessed whether there were significant volumetric changes and if changes correlated with apnea-hypopnea index (AHI) changes.
  
  
  RESULTS
  Nineteen MRIs and 18 polysomnograms were analyzed pre- and postoperation. Total airway volume increased by 19.4% (P = 0.030). Soft palate and tongue volumes decreased by 18.3% (P = 0.002) and 5.8% (P = 0.013), respectively. Retropalatal and total lateral wall volumes decreased by 49.8% (P = 0.0001) and 17.9% (P = 0.008), respectively. Changes in other structures were not significant. Eleven patients had surgical success, with a mean AHI decrease of 52.9; six were nonsuccesses with a mean AHI decrease of 4.5 (P =0.006). Decreased retropalatal lateral wall volume correlated with decreased AHI.
  
  
  CONCLUSIONS
  Airway, tongue, soft palate, and lateral wall volumes change significantly after OSA-TORS. Changes in the volume of the lateral walls correlated with changes in AHI. Volumetric upper airway MRI may be a helpful tool to better understand reasons for surgical success.
  
  
  METHODS
  4.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Hospital of the University of Pennsylvania, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, U.S.A.
authors.forename: Rebecca C
authors.initials: RC
authors.lastname: Chiffer
authors.affiliation: Department of Medicine, Division of Sleep Medicine, Pulmonary, Allergy and Critical Care Division, Penn Sleep Center, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, U.S.A.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Schwab
authors.affiliation: Perelman School of Medicine at the University of Pennsylvania, Division of Sleep Medicine, Center for Sleep and Circadian Neurobiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, U.S.A.
authors.forename: Brendan T
authors.initials: BT
authors.lastname: Keenan
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Hospital of the University of Pennsylvania, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, U.S.A.
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Borek
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Perelman School of Medicine at the University of Pennsylvania, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, U.S.A.
authors.forename: Erica R
authors.initials: ER
authors.lastname: Thaler
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009055:Mouth; D057605:Natural Orifice Endoscopic Surgery / Q000379:methods*; D010160:Palate, Soft / Q000473:pathology / Q000601:surgery*; D017286:Polysomnography; D011184:Postoperative Period; D057234:Preoperative Period; D011446:Prospective Studies; D012371:Robotics / Q000379:methods*; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult
keywords: Transoral robotic surgery; obstructive sleep apnea; uvulopalatopharyngoplasty; volumetric MRI analysis