MRI of marked dural sac compression by surgicel in the immediately postoperative period after uncomplicated lumbar laminectomy

Purpose: Our purpose was to determine what represents normal findings on MR examinations of the lumbar spine in the immediately postoperative period following lumbar laminectomy with retained Surgicel.. Method: MR examinations were performed immediately following lumbar laminectomy in 10 patients referred fos symptoms of spinal stenosis. All had Surgicel retained against the dura and were doing well postoperatively without suggestion of adverse symptoms. Images were obtained within 4 days of surgery, most within 24 h. Results: In 9 of 10 patients, severe dural tube compression was present, greater than that evident on preoperative studies. Conclusion: Marked spinal canal compression can be a normal finding in the immediately postlaminectomy period in patients with retained Surgicel. There is a lack of correlation between apparent mass effect on the thecal sac and adverse effect. The MR appearance in such instances is not significant in the absence of compressive clinical symptomatology.