Utility of Postoperative Radiographs After Anterior Lumbar Interbody Fusion With or Without Posterior Instrumentation

Abstract

Retrospective clinical and radiographical review. To evaluate the utility of plain radiographical surveillance after anterior lumbar interbody fusion and determine to what extent radiographical findings affect postoperative decision making. Postoperative radiographical surveillance is a ubiquitous practice among spine surgeons, which lacks evidence and has received growing attention in an environment of increasing health care cost and receding resources. Lumbar interbody fusions are being performed with increasing frequency from numerous approaches; nonetheless, there are no evidence-based guidelines for postoperative radiographical evaluation of patients after these procedures. One hundred forty-six consecutive patients who underwent anterior lumbar interbody fusion with or without short segment posterior fusion from 2008 to 2011 were reviewed. Exclusion criteria were less than 6 months of follow-up, prior surgery, hybrid constructs with disc arthroplasty, and concurrent posterior fusion of greater than 3 levels. Three hundred fifty-nine radiographical series and 330 clinic notes of the included 67 patients were reviewed. Radiographs were evaluated for abnormalities and clinic notes reviewed for any changes in clinical management by multiple reviewers. Interobserver reliability, sensitivity, specificity, and positive and negative predictive values were calculated. There was no single instance of a change in treatment course based on radiographical findings alone in any of the 330 clinic visits of the 67 included patients during an average 15.8-month postoperative follow-up period. Thirty-four of the 67 patients (51%) had some change in their management on the basis of their clinical symptoms and/or examination. Interobserver agreement for change in management was 0.96 (κ = 0.918). Sensitivity (6%), specificity (97%), positive predictive value (67%), and negative predictive value (50%) were calculated. Routine postoperative radiographical surveillance has minimal value for asymptomatic patients after anterior lumbar interbody fusion with or without posterior fusion. Obtaining a limited number of postoperative films of these patients in the absence of clinical symptoms or risk factors could significantly reduce health care costs and unnecessary radiation exposure.