Percutaneous ultrasonographic evaluation of the spinal cord after cervical laminoplasty: time-dependent changes.

Purpose: The first purpose of this study is to confirm whether the spinal cord and the surrounding tissues can be visualized clearly after laminoplasty using percutaneous ultrasonography. And second purpose is to evaluate the changes in the status of the spinal cord over time.

Methods: Fifty patients who underwent cervical laminoplasty with suture anchors were evaluated using intraoperative ultrasonography and postoperative (1 week, 2 weeks, 3 months, 6 months, and 1 year) percutaneous ultrasonography. We classified the decompression status of the spinal cord into three grades and the pattern of the spinal cord pulsation into six categories. Clinical outcomes were evaluated using the Japanese Orthopaedic Association Score for cervical myelopathy, and the recovery rate was calculated.

Results: In all cases and all periods, we could observe the status of the spinal cord using percutaneous ultrasonography after cervical laminoplasty. The decompression status of the spinal cord improved until 3 months postoperatively, and the clinical outcomes improved up to 6 months postoperatively. Although the pulsation pattern of the spinal cord varied in each individual and in each period, spinal pulsation itself was observed in all cases and all periods, except one, when an epidural hematoma caused quadriplegia and a revision surgery was needed. Decompression status and pulsation pattern of the spinal cord were not associated with clinical outcomes as far as pulsation was observed.

Conclusions: Percutaneous ultrasonography was very useful method to evaluate the postoperative status of the spinal cord, particularly in the diagnosis of the postoperative epidural hematoma. These slides can be retrieved under Electronic Supplementary Material.