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Purpose: To investigate the correlation between sagittalization of lumbar facet joints and lumbar intervertebral disc degeneration (IVDD). Methods: Seventy-five patients with low back pain and forty healthy volunteers (control) underwent standard MRI protocols. The basic information of all patients, including age, gender, body mass index, was collected, and the lumbar facet joint angle (LFJA) was measured on lumbar magnetic resonance imaging (MRI), and the lumbar IVDD was assessed by Pfirrmann grading. All data were analyzed statistically. Results: Compared with the control group, the LFJA of L3/4, L4/5 and L5/S1 in the patient group were significantly decreased, and there was a statistical difference (P < 0.05). The lower the segment, the more significant the sagittalization of the facet joints (P < 0.05). In the patient group, there was a statistically significant difference in the LFJA between the Pfirrmann grades of lumbar IVDD, and there was a strong negative correlation (ρ=-0.736, P < 0.05). Conclusion: With the increase of the sagittal degree of LFJA, the IVDD also increases significantly, and this relationship has a strong negative correlation. It is indicated that the sagittalization of facet joints can be an important pathological change of lumbar IVDD. The LFJA is a very good predictor for evaluating lumbar IVDD.

Background: Spinal pedicle screw internal fixation is a mature technique for the treatment of thoracolumbar fractures. A large number of studies have shown that the bending angle of the connecting rod has a significant correlation with the postoperative spinal stability. However, there has been no study to determine a reliable method to guide the bending angle of the connecting rod during operation. The purpose of our research was to explore an individualized rod bending method and analyze its effect in AO-A3 thoracolumbar fractures. Methods: The angles (angles A, B，A', B') of upper and lower motion segments before and after fracture were measured in 64 patients. By analyzing the correlations between H and angle changes(ΔA, ΔB) of the vertebra, a linear regression model was established to derive the bending angle. A total of 48 patients with fractures(AO-A3) were included and assigned to observation groups and control groups in order to measure the sagittal parameters after three years of follow-up, including LL, TK, SVA ,ASD,PT, PI and SS.Result: There was a significant linear correlation between H and angle change (ΔA, ΔB) of the vertebra. The correlation coefficient was 12.24 and 8.62,respectively. The formula for guiding bending rod was 1.50×(A’+B’)+31.29H-0.38. Compared with normal group, there were significant differences in LL, TK, PT and SS in the control group(P＜0.05), but no significant differences in the observation group(P＞0.05). The incidences of SVA>50mm were 23.08% and 22.73% in the two group respectively and the incidences of ASD were 7.69% and 13.64%, respectively. There was significant difference identified between the two groups in ASD(P＜0.05), but not in SVA＞50mm(P＞0.05). Conclusion: Using this method to guide the bending rod during the operation can well restore the sagittal angle and reconstruct the stability of the spine after operation.

Study design Anatomic study in nine fresh-frozen cadavers. Objective To confirm the anatomical feasibility of transferring the extradural ventral roots (VRs) and dorsal roots (DRs) of contralateral C7 nerves to those of the ipsilateral C7 nerves respectively through a cervical posterior approach. Summary of background data The contralateral C7 nerve root transfer technique makes breakthrough for treating spastic limb paralysis. However, its limitations include large surgical trauma and limited indications. Methods Nine fresh-frozen cadavers (four females and five males) were placed prone, and the feasibility of exposing the bilateral extradural C7 nerve roots, separation of the extradural C7 VR and DR, and transfer of the VR and DR of the contralateral C7 to those of the ipsilateral C7 on the dural mater were assessed. The pertinent distances and the myelography results of each specimen were analyzed. The acetylcholinesterase (AChE) and antineurofilament 200 (NF200) double immunofluorescent staining were preformed to determine the nerve fiber properties. Results A cervical posterior midline approach was made and the laminectomy was performed to expose the bilateral extradural C7 nerve roots. After the extradural C7 VR and DR are separated, the VR and DR of the contralateral C7 have sufficient lengths to be transferred to those of the ipsilateral C7 on the dural mater. The myelography results showed that the spinal cord is not compressed after the nerve anastomosis. The AChE and NF200 double immunofluorescent staining showed the distal ends of the contralateral C7 VRs were mostly motor nerve fibers, and the distal ends of the contralateral C7 DRs were mostly sensory nerve fibers. Conclusion Extradural contralateral C7 nerve root transfer in a cervical posterior approach for treating spastic limb paralysis is anatomically feasible. Level of evidence 5.

Background Pedicle screw fixation is a well-established technique for thoracolumbar fracture. A large number of studies have shown that the bending angle of the connecting rod has a significant correlation with the postoperative spinal stability. However, no studies have confirmed an objective indicator to guide the bending angle of the connecting rod during the operation. Our study aims to define a sagittal Cobb* angle to guide the bending angle of the connecting rod during surgery. Methods The frontal and lateral X-ray films in 150 cases of normal thoracolumbar spine were included to measure the normal spinal sagittal Cobb* angle in each segment. The patients who underwent single segment thoracolumbar fractures and pedicle screw internal fixation surgery were included. The radiological parameters included lumbar lordosis (LL), thoracic kyphosis (TK), pelvic tilt (PT), pelvic incidence (PI), sagittal vertical axis (SVA), and sacral slope (SS) were measured. The incidence of adjacent segment degeneration (ASD) 2 years after surgery was measured. Results The average values of normal sagittal Cobb* angle in each segment were − 5.196 ± 3.318° (T12), 2.279 ± 3.324° (L1), 7.222 ± 2.798° (L2), and 12.417 ± 11.962° (L3), respectively. The LL in the three groups was 35.20 ± 9.12°, 46.26 ± 9.68°, and 54.24 ± 15.31°, respectively. Compared with the normal group, there were significant differences in group A and group C, respectively (p < 0.05). The results were similar in the parameters of TL, PT, and SS. The incidences of SVA > 50 mm in group A, group B, and group C were 23.33%, 12.50%, and 19.23%, respectively. The parameter of PI in three groups was 41.36 ± 12.69, 44.53 ± 15.27, and 43.38 ± 9.85°, respectively. The incidences of ASD in group A, group B, and group C 2 years after surgery were 21.67%, 13.75%, and 17.95%, respectively. Conclusions The study confirmed that the sagittal Cobb* angle can be used as a reference angle for bending rods. When the bending angle of the connecting rod is 4 to 8° greater than the corresponding segment sagittal Cobb* angle, the patient’s spinal sagittal stability is the best 2 years after the operation.