title: Does computed tomographic assessment of inferior alveolar canal cortical integrity predict nerve exposure during third molar surgery?
abstract: OBJECTIVE
  To evaluate the association between computed tomographic (CT) assessment of inferior alveolar nerve (IAN) canal cortical integrity and intraoperative IAN exposure.
  
  
  METHODS
  This was a retrospective cohort study. The study sample included patients considered at high risk for IAN injury based on panoramic findings. The primary predictor variable was IAN canal integrity (intact or interrupted) assessed on coronal CT images. The secondary predictor variable was length of the cortical defect, in millimeters. The primary outcome variable was intraoperative visualization of the IAN. Other variables were demographic and operative parameters. Bivariate and multiple logistic regression analyses were used to evaluate the unadjusted and adjusted associations between the cortical integrity and IAN exposure. Diagnostic test characteristics were computed for cortical integrity and threshold cortical defect size. A P value < or = 0.05 was statistically significant.
  
  
  RESULTS
  The sample consisted of 51 subjects (57% female) with a mean age of 35.2 +/- 12.8 years. Of the 80 third molars available for evaluation, 52 third molars (64.1%) had evidence of loss of cortical integrity. The mean cortical defect length was 2.9 +/- 2.6 mm. Loss of cortical integrity had a high sensitivity (> or = 0.88) but low specificity (< or = 0.49) as a diagnostic test for IAN visualization. A cortical defect size > or = 3 mm was associated with an increased risk for intraoperative IAN visualization with a high sensitivity and specificity (> or = 0.82).
  
  
  CONCLUSIONS
  Cortical defect size on a maxillofacial CT has a high sensitivity and specificity for predicting intraoperative IAN exposure during third molar removal.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston, MA, USA. ssusarla1@partners.org
authors.forename: Srinivas M
authors.initials: SM
authors.lastname: Susarla
authors.forename: Harlyn K
authors.initials: HK
authors.lastname: Sidhu
authors.forename: Laura L
authors.initials: LL
authors.lastname: Avery
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Dodson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015331:Cohort Studies; D020209:Cranial Nerve Injuries / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D016015:Logistic Models; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000294:innervation* / Q000473:pathology; D008340:Mandibular Nerve / Q000000981:diagnostic imaging / Q000473:pathology; D008875:Middle Aged; D008964:Molar, Third / Q000601:surgery*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011862:Radiography, Panoramic; D012189:Retrospective Studies; D020886:Somatosensory Disorders / Q000209:etiology; D014057:Tomography, X-Ray Computed; D014081:Tooth Extraction / Q000009:adverse effects*; D061221:Trigeminal Nerve Injuries; D055815:Young Adult