Use of goniometry to predict inadequate flexion-extension roentgenograms: a preliminary study.

Background: Flexion-extension roentgenograms (FER) of the cervical spine are often inadequate because of limited range of motion (ROM). The purpose of this study was to determine the utility of goniometry to predict a patient's ability to achieve sufficient ROM to obtain adequate FER.

Methods: We evaluated 65 consecutive blunt trauma patients undergoing evaluation by FER in the emergency department. Patients were evaluated by goniometry before performing FER. Adequate ROM was defined as flexion and extension of >30 degrees from neutral.

Results: Seventy-five percent of patients had adequate FER. All of these patients were predicted to have sufficient ROM by goniometry. Goniometry predicted limited ROM in 69% of patients who had inadequate FER. The positive predicative value of goniometry in predicting inadequate FER was 100%. The incidence of cervical spine injuries was 44% in patients with inadequate ROM by goniometry and 23.0% in patients with inadequate FER (versus 7.69% in patients with adequate FER).

Conclusion: Goniometry accurately predicted those patients who were unable to achieve sufficient ROM for adequate FER. Patients with inadequate FER were at a higher risk for cervical spine injury compared with patients with adequate FER (23.0 versus 7.69%). Early identification of these patients will help limit the number of inadequate studies obtained and expedite evaluation of high-risk patients.