title: Three-dimensional morphological changes of the temporomandibular joint and functional effects after mandibulotomy.
abstract: BACKGROUND
  The midline and paramedian mandibulotomy are surgical procedures that divide the mandibular bone into two halves and disconnects the condylar heads of the TMJ from each other. This study aimed to prospectively evaluate the temporomandibular joint (TMJ) functional and morphological changes after mandibulotomy using a reconstructed 3D models of the TMJ.
  
  
  METHODS
  Sixteen adult patients diagnosed with oral and oropharyngeal tumors with planned surgical mandibulotomy (test group, 9 patients) or transoral (control group, seven patients) treatments were included in the study. MRI and CBCT images were obtained immediately preceeding surgery and 6-8 weeks after surgery. Using the MRI-CBCT registered images, TMJ tissues were segmented at the two occasions by the same operator and 3D models were reconstructed for morphological assessment. Changes across time were measured using the volume overlap and Hausdorff distance of the disc and condyle 3D models. Disc-condyle relationship was measured using point-based and color map analysis. To assess the early functional changes, the Jaw function limitation scale (JFLS) and the maximum mouth opening were measured. Two-sample Hotelling T2t-test was performed to determine the significance of the morphological and clinical outcomes' differences between the two groups.
  
  
  RESULTS
  The two-sample Hotelling T2t-test showed significant differences (T2(df1,df2) = 0.97 (5,26), p <0.01) between the mean values of all outcomes among the 2 groups. The change in disc displacement was significantly different between the two groups (p <0.05). However, the condylar displacement was not significantly different between the two groups (p =0.3). The average of the JFLS score was five times larger after mandibulotomy, and was 2 times larger after transoral surgery (p < 0.01). Patients showed decrease in the average of the maximum interincisal mouth opening by 11 mm after mandibulotomy, and by 5.4 mm after transoral surgery.
  
  
  CONCLUSIONS
  The quantitative assessment of the TMJ showed minimal changes of the condylar position and variable degrees of articular disc displacement associated with the paramedian split mandibulotomy. As well, limited jaw functions and vertical mouth opening were noticed more in the mandibultomy group compared to the transoral group in 6- weeks after surgery.
authors.affiliation: Orthodontic Graduate Program, School of Dentistry, University of Alberta, 476 Edmonton Clinic Health Academy (ECHA), Edmonton, Alberta, T6G 1C9, Canada. m.alsaleh@ualberta.ca.
authors.forename: Mohammed A Q
authors.initials: MA
authors.lastname: Al-Saleh
authors.affiliation: Servier Virtual Cardiac Centre, Mazankowski Alberta Heart Institute and Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, T6G 2B7, Canada.|Department of Computing Science, Faculty of Science, University of Alberta, Athabasca Hall, Room 411, Edmonton, Alberta, T6G 2E8, Canada.
authors.forename: Kumaradevan
authors.initials: K
authors.lastname: Punithakumar
authors.affiliation: Orthodontic Graduate Program, School of Dentistry, University of Alberta, 476 Edmonton Clinic Health Academy (ECHA), Edmonton, Alberta, T6G 1C9, Canada.
authors.forename: Manuel
authors.initials: M
authors.lastname: Lagravere
authors.affiliation: Servier Virtual Cardiac Centre, Mazankowski Alberta Heart Institute and Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, T6G 2B7, Canada.|Department of Computing Science, Faculty of Science, University of Alberta, Athabasca Hall, Room 411, Edmonton, Alberta, T6G 2E8, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Boulanger
authors.affiliation: Department of Radiology and Diagnostic Imaging, Faculty of Medicine and Dentistry, University of Alberta, 2A2.41 WC Mackenzie Health Science Center, Edmonton, Alberta, T6G 2R7, Canada.
authors.forename: Jacob L
authors.initials: JL
authors.lastname: Jaremko
authors.affiliation: Division of Otolaryngology Head and Neck Surgery, Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, 16940-87 Avenue, Edmonton, Alberta, T5R 4H5, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Wolfaardt
authors.affiliation: Orthodontic Graduate Program, School of Dentistry, University of Alberta, 476 Edmonton Clinic Health Academy (ECHA), Edmonton, Alberta, T6G 1C9, Canada.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Major
authors.affiliation: Division of Otolaryngology Head and Neck Surgery, Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, 16940-87 Avenue, Edmonton, Alberta, T5R 4H5, Canada.
authors.forename: Hadi
authors.initials: H
authors.lastname: Seikaly
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D063168:Mandibular Osteotomy; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000601:surgery*; D009959:Oropharyngeal Neoplasms / Q000601:surgery*; D011446:Prospective Studies; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology*
keywords: 3D image analysis; CBCT; MRI; Mandibulotomy; TMJ; TMJ segmentation