[Application of intraoperative spinal ultrasonography in cervical laminoplasty]

To investigate the clinical value of intraoperative ultrasonography in cervical laminoplasty.

Thirty patients underwent cervical laminoplasty for cervical compressive myelopathy in our hospital from April 2010 to April 2012. Spinal cord compression ratio was calculated in preoperative MRI axial images for every patient. The spinal cord decompression status was evaluated by intraoperative ultrasonography during cervical laminoplasty. The pre- and post-operative Japanese Orthopaedic Association Scoring System (JOA) score was recorded, and the recovery ratios of surgery were graded using the Hirabayashi equation. The relationship between the parameters and neural recovery was explored.

The intraoperative ultrasonography was used to evaluate the ventral compression of the spinal cord. The ultrasonographic dynamic viewings were classified into three types based on the spinal cord contact with ventral structures after decompression: Type 1, non-contact (n=2); Type 2, contact and apart (n=16); and Type 3, contact (n=12). The patients were divided into two groups: group A, showing Type 1 or 2 findings, representing satisfied decompression; and group B, showing Type 3 findings with insufficient decompression. The recovery ratio was (73.3±21.0)%(31.3%-100.0%) in group A, but decreased to (43.2±33.1)%(0-83.3%) in group B(t=3.05,p=0.005). Pearson analysis showed that the patient age(r=-0.294,p=0.122), preoperative JOA score(r=0.059,p=0.759), and spinal compression ratio(r=0.269,p=0.151) was not correlated with Hirabayashi recovery ratio.

Intraoperative ultrasonography during laminoplasty is a feasible and promising method for evaluating spinal cord decompression status and predicting the prognosis following surgery.