Preoperative computed tomography imaging in the management of impacted mandibular third molars.
OBJECTIVE
The purpose of this study was to examine the role of preoperative computed tomography (CT) imaging of the inferior alveolar nerve (IAN) for patients at increased risk for nerve injury during mandibular third molar (M3) extraction.


METHODS
To address the research purpose, the investigators enrolled a sample composed of subjects who presented for mandibular M3 extraction and had panoramic radiographic signs interpreted as being associated with an increased risk for inferior alveolar nerve injury. All subjects had preoperative CT imaging studies done to ascertain the position of the IAN with respect to M3. The predictor variable was the preoperative assessment of risk for IAN injury based on panoramic imaging. The outcome variable was the preoperative assessment of IAN injury risk after reviewing the CT studies. We documented the number of IAN injuries. Descriptive statistics were computed as indicated.


RESULTS
The sample consisted of 23 patients who had bilaterally impacted wisdom teeth. The sample's mean age was 26 +/- 6 years (range: 18-48 years); 69.6% of the patients were female. After reviewing the panoramic radiographic, 80.4% of M3s were classified as having an increased risk for IAN injury. Upon examining the CT imaging, 32.6% were classified as high risk for IAN injury. After reviewing all imaging studies, 71.7% of the teeth in the sample were extracted. Intraoperative IAN visualization occurred in 21.2% of the cases. At 1 week postoperative, 3 patients had dysesthesia (9.1%); none had a permanent nerve injury.


CONCLUSIONS
In this small series of patients, the additional information provided by 3-dimensional imaging changed the majority of patients from increased risk for nerve injury to low risk for nerve injury.
Susarla
Srinivas M
SM
Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston, MA 02114, USA. ssusarla@student.hms.harvard.edu
Dodson
Thomas B
TB
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007430:Intraoperative Care; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging* / Q000294:innervation; D008340:Mandibular Nerve / Q000000981:diagnostic imaging; D008875:Middle Aged; D008964:Molar, Third / Q000000981:diagnostic imaging* / Q000294:innervation; D010292:Paresthesia / Q000209:etiology; D011183:Postoperative Complications; D011300:Preoperative Care; D011862:Radiography, Panoramic; D012189:Retrospective Studies; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed / Q000379:methods; D014095:Tooth, Impacted / Q000000981:diagnostic imaging* / Q000601:surgery; D061221:Trigeminal Nerve Injuries