The effect of the X-Stop implantation on intervertebral foramen, segmental spinal canal length and disc space in elderly patients with lumbar spinal stenosis

Objectives To evaluate the biomechanical effect of the X-Stop device on the intervertebral foramen (IVF) and segmental spinal canal length (SSCL), as well as the intervertebral disc space at the implanted and the adjacent segments in patients with lumbar spinal stenosis (LSS). Materials and methods Eight elderly patients with LSS, scheduled for X-stop implantation, were CT or MRI scanned to construct 3D vertebral models (L2–S1). Before and after the surgery, each patient was also imaged using a dual-fluoroscopic image system during weight-bearing standing and maximum extension–flexion. The positions of the vertebrae were then determined using an established 2D–3D model matching method. Results The data revealed that the postoperative IVF area was significantly increased by 32.9% (or 32 mm 2 ) ( p