The demographic and clinical data of patients, including age, sex, body mass index (BMI), surgical segment, operation time, blood loss volume, drainage tube placement time, length of hospital stay, the total cost of hospitalization, and complications, were collected from the medical records. The weighted Charlson Comorbidity Index (CCI) [16 (link)] and the American Society of Anesthesiologists’ physical status classification (ASA) [17 (link)] were used to assess the preoperative physical condition of these patients.
The Numerical Rating Scale (NRS) for back and leg pain [18 (link)], the validated simplified Chinese version of Oswestry Disability Index (ODI) [19 (link)], and the validated simplified Chinese version of Short-Form Health Survey (SF-36) [20 (link)] were collected before surgery and at 3, 6, and 12 months after surgery. SF-36 was divided into 2 parts for statistical analysis: Physical Component Summary (PCS) and Mental Component Summary (MCS). The improvement value was used as the indexes of clinical outcomes and defined as the change between the score at follow-up and the preoperative score.
The preoperative radiographic data included all-spine lateral radiograph, extension-flexion lateral radiograph, lumbar magnetic resonance imaging (MRI), and bone density test. An immediate postoperative lumbar lateral radiograph was performed to determine if the screws were positioned correctly. All-spine lateral X-rays were performed at 3, 6, and 12 months. A lumbar MRI was performed at 6 and 12 months. Lumbar computed tomography (CT) was performed at 12 months. Preoperative and postoperative all-spine lateral radiographs were used to evaluate the sagittal parameters and implant-related complications and to record the preoperative osteoporotic compression vertebra fractures (OVF) and the postoperative new-onset OVF. All sagittal spino-pelvic parameters were collected, including sagittal vertical axis (SVA), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), upper thoracic kyphosis angle (T2-T5), lower thoracic kyphosis angle (T5-T12), thoracolumbar lordosis angle, and lumbar lordosis angle (LLA) (T12-S1) at each follow-up time point [21 (link)]. The bone union status was assessed using the postoperative CT. The Pfirrmann index was used to grade the degree of adjacent disc degeneration from levels 1 to 8 [22 (link)]. The middle part of the disc was selected in T2WI sagittal lumbar MRI images to obtain the Pfirrmann index to ensure consistency of grading criteria. For patients without L5/S1 fusion, the Pfirrmann index was defined as the average of the upper and lower adjacent segment discs. For patients with L5/S1 fusion, the Pfirrmann index referred to the upper adjacent segment disc.
The Numerical Rating Scale (NRS) for back and leg pain [18 (link)], the validated simplified Chinese version of Oswestry Disability Index (ODI) [19 (link)], and the validated simplified Chinese version of Short-Form Health Survey (SF-36) [20 (link)] were collected before surgery and at 3, 6, and 12 months after surgery. SF-36 was divided into 2 parts for statistical analysis: Physical Component Summary (PCS) and Mental Component Summary (MCS). The improvement value was used as the indexes of clinical outcomes and defined as the change between the score at follow-up and the preoperative score.
The preoperative radiographic data included all-spine lateral radiograph, extension-flexion lateral radiograph, lumbar magnetic resonance imaging (MRI), and bone density test. An immediate postoperative lumbar lateral radiograph was performed to determine if the screws were positioned correctly. All-spine lateral X-rays were performed at 3, 6, and 12 months. A lumbar MRI was performed at 6 and 12 months. Lumbar computed tomography (CT) was performed at 12 months. Preoperative and postoperative all-spine lateral radiographs were used to evaluate the sagittal parameters and implant-related complications and to record the preoperative osteoporotic compression vertebra fractures (OVF) and the postoperative new-onset OVF. All sagittal spino-pelvic parameters were collected, including sagittal vertical axis (SVA), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), upper thoracic kyphosis angle (T2-T5), lower thoracic kyphosis angle (T5-T12), thoracolumbar lordosis angle, and lumbar lordosis angle (LLA) (T12-S1) at each follow-up time point [21 (link)]. The bone union status was assessed using the postoperative CT. The Pfirrmann index was used to grade the degree of adjacent disc degeneration from levels 1 to 8 [22 (link)]. The middle part of the disc was selected in T2WI sagittal lumbar MRI images to obtain the Pfirrmann index to ensure consistency of grading criteria. For patients without L5/S1 fusion, the Pfirrmann index was defined as the average of the upper and lower adjacent segment discs. For patients with L5/S1 fusion, the Pfirrmann index referred to the upper adjacent segment disc.
