Analysis of motion segment between lower thoracic and lumbar vertebra

<p>Introduction: The postoperative period of spinal fusion surgery is marked by stiffness disability. However, little data is available on the details of the mobility of each intervertebral segment. Therefore, we investigated the mobility of each intervertebral segment.</p><p>Materials and Methods: Patients with degenerative spine disease who underwent surgery were reviewed. We measured mobile angle on each segment from T11/12 to L5/S1 by preoperative flexion/extension radiographic on sitting position.</p><p>Results: One hundred fourteen patients were included in this study. The average age was 65.5 years old. The overall mobility of the T11-S1 was 33.6°. L3/4 had the largest mobility of 6.71°, and the percentage to the total range of motion was 20.0%. T11/12 had the smallest mobility of 1.92°, and the percentage of the total range of motion was 3.4%. The standard deviation was 4.47 for L4/5, the largest variability, and 3.04 for L5/S1, the smallest variability. Dividing the results into lower L4-S1, middle L2-4, and upper T11-L2, L4-S1: 29.2%, L2-4: 39.7%, and T11-L2: 31.1%, with the largest range of motion in L2-4. Paradoxical motion was observed in 67 vertebrae (8.4%), with T11/12 having the highest level of paradoxical motion (27 segments). There was a low negative correlation between the percentage of the range of motion at T11-L2 and age (r = -0.21, p = 0.02).</p><p>Conclusion: It was possible to maintain a range of about 30% by reducing the lower fusion end to L4 or the upper fusion end to L2, respectively, in long spinal fusion. The data from this study could be used as an indicator.</p>