title: Magnetic resonance evaluation of the disk before and after arthroscopic surgery for temporomandibular joint disorders.
abstract: OBJECTIVE
  The purposes of this study were (1) to assess functional and pain outcomes after arthroscopic surgery on patients with temporomandibular joint disorders (TMD); (2) to evaluate postsurgical changes in disk position, mobility, and morphology on magnetic resonance imaging (MRI); and (3) to measure the association between changes in disk position, mobility, and morphology on MRI and clinical outcomes.
  
  
  METHODS
  A retrospective analysis was conducted of temporomandibular joints with internal derangement and osteoarthritis that were refractory to nonsurgical treatments and underwent arthroscopic surgery and on which MRI was performed within 1 month after the initial visit and 1 year after arthroscopic surgery. Clinical findings were assessed on the basis of mandibular range of motion and joint pain level on a visual analog scale at the initial visit and 1 year after arthroscopic surgery. The disk position, mobility, and morphology on MRI were compared with clinical findings and were statistically analyzed before and after arthroscopic surgery. The treatment outcome was judged according to our success criteria. The associations between changes in disk position, mobility, and morphology and clinical outcomes after arthroscopic surgery were statistically analyzed.
  
  
  RESULTS
  Forty-three joints of 43 patients who underwent arthroscopic surgery were assessed in this study. After arthroscopic surgery, mandibular range of motion and visual analog scale results improved statistically. According to the criteria for clinical resolution, 32 surgeries were successful and 11 were unsuccessful. Preoperative and postoperative MRI showed that most joints had anterior disk displacement (ADD) without reduction. Postoperative MRI revealed that, statistically, the number of mobile disks had increased and deformity of the disks had progressed. In the successful group, postoperative MRI revealed that all joints had mobile disks. In both groups, most joints had ADD without reduction before and after arthroscopic surgery, and, statistically, deformity of the disks progressed after arthroscopic surgery.
  
  
  CONCLUSIONS
  Arthroscopic surgery was an effective treatment for TMD refractory to nonsurgical treatments. This study provides important information of clinical significance. Disk position remained ADD without reduction, disk mobility increased, and deformity of the disks progressed after arthroscopic surgery.
authors.affiliation: Division of Dentistry and Oral Surgery, Akita University School of Medicine, Akita, Japan. ohnuki@arc.med.akita-u.ac.jp
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ohnuki
authors.forename: Masayuki
authors.initials: M
authors.lastname: Fukuda
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Iino
authors.forename: Tetsu
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001182:Arthroscopy; D005157:Facial Pain / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D004204:Joint Dislocations / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D010147:Pain Measurement; D016059:Range of Motion, Articular / Q000502:physiology; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D019224:Temporomandibular Joint Disc / Q000473:pathology* / Q000503:physiopathology; D013705:Temporomandibular Joint Disorders / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome