Fig. 3

IDSS was surgically implanted at the L4/5 segment. a Preoperative radiographic evaluation revealed stable L4-5 alignment without evidence of spondylolisthesis or segmental instability. b-c Preoperative lumbar CT and MRI demonstrated L4-5 spinal canal stenosis with bilateral nerve root compression. d-e Postoperative CT and MRI follow-up confirmed optimal implant positioning depth with partial bilateral facetectomy. Quantitative analysis demonstrated FJPR of 71.3% (right) and 83.4% (left), accompanied by SCAER of 124%. f-g Final follow-up dynamic flexion-extension radiographs revealed preserved segmental stability at L4/5, though with significant reduction of SROM compared to preoperative measurements. ISH maintained consistency with preoperative baseline values