A Study on the Clinical Use of a New Expandable OLIF Cage With Posterior Bone Grafting in Lumbar Spine Surgery

Radiological follow-up will be conducted immediately after surgery, and at 6, 12 months postoperatively using X-ray and/or CT imaging. Cage subsidence is defined as: ≥2 mm of cage penetration into the adjacent vertebral endplate compared to immediate postoperative imaging; Visible collapse of the cage-endplate interface; ≥10% reduction in intervertebral height compared to initial postoperative height. All radiographic assessments will be performed independently by two spine surgeons or radiologists blinded to group allocation. In case of discrepancy, a third reviewer will adjudicat

Endplate injury will be assessed intraoperatively by the operating surgeon through direct visual inspection and intraoperative fluoroscopy. Injury is defined as any of the following: Visible collapse, fracture, or tearing of the cartilaginous endplate during cage insertion; Evidence of asymmetric or excessive endplate compression on fluoroscopy; Explicit documentation of "endplate injury" or "endplate violation" in the operative record. Injury will be recorded in binary form (Yes/No). When necessary, postoperative CT scans may be used to confirm suspected endplate damage.

On lateral X-ray or CT images, the target intervertebral space is selected, and the intervertebral space heights of the leading edge, middle point and trailing edge are measured respectively, and the average value is taken to represent the intervertebral height of this segment.

Visual Analog Scale, (VAS) of pain. Measurement method: Patients were evaluated by VAS score before operation, 3 months, 6 months and 12 months after operation. Use a horizontal scale of 10 cm, with one end marked as "0 = painless" and the other end marked as "10 = the most severe pain". The patient draws a line on the ruler according to his own feelings, and measures the distance (in centimeters) from the starting point of "0" to the drawing point as the scoring result..

Used to evaluate lumbar scoliosis or coronal imbalance. Measurements are performed on preoperative and postoperative standing anteroposterior (AP) lumbar spine radiographs or coronal CT reconstructions. Identify the most tilted upper end vertebra and the most tilted lower end vertebra in the coronal plane; Draw lines along the upper endplate of the upper vertebra and the lower endplate of the lower vertebra; Construct perpendicular lines to each endplate line; The angle between these two perpendiculars is recorded as the coronal Cobb angle. The angle is recorded in degrees (°).

Draw lines along the superior endplate of L1 and the superior endplate of S1; The angle formed between these two lines is defined as the sagittal Cobb angle (lumbar lordosis angle). The angle is recorded in degrees (°).

Oswestry Disability Index, (ODI). Measurement method: The Chinese version of ODI scale was used, which was completed by patients' self-evaluation, including 10 items (such as pain intensity, personal care, walking, social life, etc.), and each item was scored at 5 levels. The total score is 50 points.In this study, a lower ODI score postoperatively reflects better functional recovery and greater treatment effectiveness.