title: Intraoperative condyle positioning by sonographic monitoring in orthognathic surgery verified by MRI.
abstract: OBJECTIVE
  Repositioning of the jaw in orthognathic surgery must produce precise and stable long-term results; an effective and practical method of intraoperative condyle positioning is required to achieve this. Most traditional methods, such as manual positioning or positioning plates do not permit intraoperative monitoring of the temporomandibular joint (TMJ) position. This study evaluates the results of intraoperative, sonographically-monitored joint positioning, comparing preoperative and postoperative MRI scans.
  
  
  METHODS
  Of the 97 patients who were originally assessed (53 female, average age 29 ± 10.93; and 44 male, average age 28 ± 9.25), 21 had incomplete data sets and were excluded, leaving 76 evaluable patients. MRIs were performed preoperatively between 2 days and 100 weeks (median 30.5 days), and postoperatively between 12 and 96 weeks (median 150 days). Condyle positioning, intercondylar distance, and disc degeneration and dislocation were compared in preoperative and postoperative MRIs, and differentiated by Angle class on horizontal, axial and sagittal scans. Condyle to fossa distances were measured on parasagittal images from 0° (the vertical sagittal plane), 45° anteriorly and 45° posteriorly. The intercondylar distances between the condylar head midpoints were measured on axial sections. Two-sided t-tests (α < 0.05) were used for comparisons within classes; the interclass correlation was performed using univariate ANOVA and linear correlation for paired sample correlation settings.
  
  
  RESULTS
  In 27 Angle class II cases, the anterior distance of both condyles increased on average 0.3 ± 1.0 mm, the posterior position decreased 0.1 ± 1.2 mm, and the vertical position decreased 0.2 ± 1.1 mm postoperatively. In 47 Angle class III cases the anterior distance of both condyles increased on average 0.3 ± 0.8 mm, the posterior 0.1 ± 0.8 mm and the vertical distance 0.1 ± 0.8 mm postoperatively. All alterations of the condyle-fossa relation were non-significant except for the anterior distance in Angle class ІІІ (p = 0.02). Alterations of the disc position and disc degeneration were non-significant in class II. In class ІІІ, the disc degeneration deteriorated slightly on the left side (p = 0.02). Intercondylar distance increased 1 ± 5.5 mm in class ІІ and decreased by 1 ± 5.5 mm in class ІІІ postoperatively, alterations were non-significant.
  
  
  CONCLUSIONS
  Sonography is a non-invasive, comfortable, fast, economical and effective intraoperative method of condyle positioning. The results of the present study support this statement because the degree of disc degeneration and luxation remained unaltered and the condyle position did not change significantly. Prospective randomized comparison to manual positioning is in preparation and will be conducted in the near future.
authors.affiliation: Cranio-Maxillofacial and Plastic Facial Surgery, (Head: Sader Robert, M.D., D.M.D., Ph.D., FEBOMFS), J. W. Goethe-University of Frankfurt Medical Center, Frankfurt, Germany. Electronic address: bethgelena@gmail.com.
authors.forename: Lena Sydney
authors.initials: LS
authors.lastname: Bethge
authors.affiliation: Cranio-Maxillofacial and Plastic Facial Surgery, (Head: Sader Robert, M.D., D.M.D., Ph.D., FEBOMFS), J. W. Goethe-University of Frankfurt Medical Center, Frankfurt, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Ballon
authors.affiliation: Cranio-Maxillofacial and Plastic Facial Surgery, (Head: Sader Robert, M.D., D.M.D., Ph.D., FEBOMFS), J. W. Goethe-University of Frankfurt Medical Center, Frankfurt, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Mack
authors.affiliation: Cranio-Maxillofacial and Plastic Facial Surgery, (Head: Sader Robert, M.D., D.M.D., Ph.D., FEBOMFS), J. W. Goethe-University of Frankfurt Medical Center, Frankfurt, Germany.
authors.forename: Constantin
authors.initials: C
authors.lastname: Landes
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005355:Fibrosis; D005500:Follow-Up Studies; D006801:Humans; D007430:Intraoperative Care; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008312:Malocclusion, Angle Class II / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008313:Malocclusion, Angle Class III / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000473:pathology*; D008875:Middle Aged; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000473:pathology; D054850:Osteophyte / Q000000981:diagnostic imaging / Q000473:pathology; D019340:Osteotomy, Le Fort / Q000379:methods; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods; D016059:Range of Motion, Articular / Q000502:physiology; D013701:Temporal Bone / Q000000981:diagnostic imaging / Q000473:pathology; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D019224:Temporomandibular Joint Disc / Q000000981:diagnostic imaging / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000000981:diagnostic imaging / Q000473:pathology; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional / Q000379:methods*; D055815:Young Adult
keywords: Condylar positioning; Disc displacement; Joint degeneration; MRI; Orthognathic surgery; Temporomandibular joint