PMCF Study on the Effectiveness and Safety of METROSAN Spinal Systems and BONEGRAFT Filling Materials

The NDI is used to evaluate neck-pain-related disability. It consists of 10 items, each scored from 0 to 5. While the total raw score ranges from 0 to 50, results are expressed as a percentage (0-100%) for clinical evaluation, consistent with the referenced literature (Heller et al., 2009). Following clinical benchmarks, a reduction of ≥15% in the NDI score at the 12th-month follow-up compared to baseline is defined as a successful clinical improvement.

The ODI is used to assess the impact of thoracolumbar pain on daily life activities (personal care, lifting, walking, sitting, standing, sleeping, sexual life, social life, and travel). It consists of 10 items, each scored from 0 to 5. The total score is calculated using the formula: (total score x 100) / (5 x number of questions answered), resulting in a scale from 0 (best) to 100 (worst). Evaluations will be performed at baseline (pre-op) and at each follow-up visit (Day 12, Week 6, and Months 3, 6, and 12).

A reduction of ≥15 points in the ODI score at the 12th-month follow-up compared to baseline is defined as a successful clinical improvement.

Fusion status will be evaluated using radiographs and/or CT scans (if available) at each postoperative follow-up visit. The assessment is based on the presence of a continuous trabecular bone bridge between the vertebral bodies. Fusion will be categorized into three groups:

Solid Fusion: Presence of a continuous bone bridge between the vertebrae.

Fibrous Fusion: Absence of a continuous bone bridge, but no signs of instability (translation < 3 mm on dynamic radiographs).

Non-fusion: Absence of a continuous bone bridge along with abnormal motion (> 3 mm translation on radiographs).

The evaluation will be concluded once solid fusion is achieved.

In subjects undergoing dynamic posterior stabilization, motion at the adjacent segments will be evaluated using flexion and extension radiographs (if available) at all follow-up visits. The primary assessment involves measuring the differences in the disc space angles. These measurements will be compared with baseline (preoperative) values to monitor changes in adjacent segment mobility over the 12-month follow-up period.

The intervertebral disc height will be evaluated at each follow-up visit using the Dabbs method. The assessment is based on the average of the measurements taken from the anterior and posterior regions of the disc space, expressed in millimeters (mm) by the formula (A+B)/2. These radiological measurements will be compared with preoperative (baseline) values to identify any changes in disc height throughout the 12-month follow-up period.

Intervertebral disc degeneration will be evaluated at each follow-up visit using the Pfirrmann Classification system. This system grades the degree of disc degeneration based on MRI (Magnetic Resonance Imaging) findings, focusing on disc structure, distinction between nucleus and annulus, signal intensity, and disc height. The scale ranges from Grade I (normal disc structure with high signal intensity) to Grade V (severe degeneration with collapsed disc space). Categorical grades obtained at each control period will be compared with baseline (preoperative) status to monitor the progression or stabilization of disc degeneration throughout the 12-month follow-up period, where a shift toward higher grades signifies worsening of degeneration.

Cervical and segmental lordosis will be evaluated at each follow-up visit and compared with preoperative measurements. Lateral radiographs of the cervical spine will be used to measure lordosis angles using the Cobb angle method. This assessment aims to monitor the maintenance or restoration of the sagittal alignment of the cervical spine and the specific treated segments throughout the 12-month follow-up period.

Sagittal balance and lordosis restoration will be evaluated using full-spine radiographs (tele-radiographies, if available) at baseline and each follow-up visit (Day 12, Week 6, Months 3, 6, and 12). Clinical success will be assessed based on the Schwab sagittal alignment classification parameters. This assessment is a categorical evaluation based on whether patients achieve the predefined optimal correction thresholds for three key spinal parameters: 1) Sagittal Vertical Axis (SVA) < 50 millimeters, 2) Pelvic Tilt (PT) < 20 degrees, and 3) Pelvic Incidence minus Lumbar Lordosis (PI-LL) mismatch within ±9 degrees. At each follow-up period, patients will be categorized into two groups: those who achieve all these optimal parameters and those who do not. Patients meeting all three thresholds will be classified as 'successful' according to the Schwab criteria.

Safety data will be collected by recording all adverse events (AEs) and complications encountered during the 12-month follow-up period. This includes intraoperative complications, device-related failures, and any postoperative adverse events (e.g., infection, neurological deficit, or reoperation).

Patient clinical outcomes will be evaluated at each follow-up visit using Odom's Criteria, which classifies results as 'Excellent', 'Good', 'Fair', or 'Poor' based on symptom relief and the ability to perform daily activities. Clinical success is defined as the proportion of subjects achieving 'Excellent' or 'Good' scores, representing significant improvement compared to baseline.

Pain intensity and changes in pain levels will be evaluated at each follow-up visit using the Visual Analog Scale (VAS) and compared with baseline measurements. Patients mark their pain level on a 100 mm (or 10 cm) line, where 0 represents no pain and 100 represents the worst pain. A decrease of ≥20 mm (or 2 cm) in pain intensity at the 12th-month follow-up compared to baseline is considered a successful clinical outcome.

Health-related quality of life and changes in quality of life perception will be evaluated at each follow-up visit using the SF-12 Health Survey and compared with baseline measurements. Each domain of the survey is evaluated independently. Scores for each domain range from 0 to 100, where 0 represents the worst possible health state and 100 represents the best possible health state.

Patient satisfaction will be evaluated at the final follow-up visit (12 months) using a 3-point Likert scale based on three specific questions directed to the subject. The scale consists of three response options: 'Yes', 'Undecided', and 'No'. The proportion of patients responding 'Yes' to the satisfaction questions will be analyzed to determine the overall treatment satisfaction rate.