BACKGROUND:Upright rat intervertebral disc degeneration model can prove that intervertebral fusion can aggravate the adjacent-segment intervertebral disc degeneration, but cannot affirm that spinal non-fusion technology has more advantages. OBJECTIVE:Base on the affirmed intervertebral disc degeneration models of Beagle dog, we performed intervertebral fusion to affirm whether or not the intervertebral fusion can aggravate the adjacent-segment intervertebral disc degeneration. METHODS:Twelve Beagle dogs were randomly divided into two groups. The control group animals were stabbed percutaneous to injure L5/6 disc. The experimental group animals were stabbed percutaneous to injur L5/6 disc. One month later, we made L4/5 intervertebral fusion. At 3 and 6 months postoperatively, lumbar MRI was conducted. L5/6 discs were harvested and subjected to histological observation and PCR. RESULTS AND CONCLUSION:(1) MRI:in the experimental group, 3 and 6 months after fusion, different degrees of intervertebral disk herniation appeared. In the control group, no obvious intervertebral disk herniation appeared. (2) Histological observation:6 months after fusion, in the experimental group, intervertebral disc annulus and nucleus pulposus were disordered;there was a gap in the fold, and the number of nucleus pulposus cel s decreased. In the control group, nucleus pulposus and anulus fibrosus boundary was clear;col agen was loose and arranged regularly. Cel number was more. Anulus fibrosus was close to normal. Col agen fibers were regular and dense. In the experimental group, 3 and 6 months after fusion, type II col agen-positive cel s were less than the control group (P<0.05). Moreover, type II col agen-positive cel s were less at 6 months than at 3 months in the experimental group (P<0.05). (3) PCR:Bone morphogenetic protein 15 and tissue inhibitor of matrix metal oproteinase 1 gene expression was higher in the experimental group than in the control group at 3 and 6 months after fusion (P<0.05). Bone morphogenetic protein 15 and tissue inhibitor of matrix metal oproteinase 1 gene expression was higher in the experimental group at 6 months than that at 3 months (P<0.05). (4) These results suggest that intervertebral fusion can aggravate the adjacent-segment intervertebral disc degeneration.

Objective To evaluate the efficacy of unilateral atlanto-axial transpedicle screw fixation plus iliac bone graft for treatment of unstable atlas fractures combined with unilateral pedicle dysplasia or comminuted fractures.Methods A retrospective case control study was made on 44 patients with unstable atlas fractures surgically treated between January 2012 to June 2016.Unilateral atlanto-axial transpedicle screw fixation combined with iliac bone graft was performed for 22 patients combined with unilateral pedicle dysplasia or comminuted fractures in Group A[15 males,seven females;(37.5 ± 13.4)years],and bilateral atlanto-axial transpedicle screw fixation combined with iliac bone graft was performed for 22 patients without unilateral pedicle dysplasia or comminuted fractures in Group B [14 males,eight females;(38.1 ± 13.3)years].Between-group differences were compared concerning operation time,intraoperative blood loss,length of hospital stay,success rate of screw placement,postoperative atlantoaxial stability,surgery-related complications,visual analog scale (VAS),Japanese orthopedic association score (JOA) and bone fusion.Results Mean duration of follow-up was 28.4 months (range,14-48 months).In Group A,operation time was (123.4 ± 18.2) min,blood loss was (218.5 ± 80.2) ml,hospital stay was (7.1 ± 1.0)d,success rate of screw placement was 100％,postoperative atlanto-axial stability of all patients was obtained,and no complications occurred.In Group B,operation time was (173.4 ± 12.4) min,blood loss was (318.2 ± 61.7) ml,hospital stay was (7.2 ± 0.8) d,success rate of screw placement was 100％,postoperative atlanto-axial stability of all patients was obtained,and no complications occurred.There were significant differences in operation time and blood loss between the two groups (P ＜0.01),while not in hospital stay,success rate,postoperative atlant-oaxial stability,complication incidence,VAS and JOA (P ＞ 0.05).Conclusion Both treatments are effective,but unilateral atlanto-axial transpedicle screw fixation combined with iliac bone graft is associated with relatively shorter operation time and less blood loss and hence is considered as a better choice for treatment of unstable atlas fractures.

Objective:To explore the clinical efficacy of open-door laminoplasty in treatment of cervical spinal hyperextension injury accompanied with or without spinal cord-canal mismatch.Methods:A retrospective case-control study was performed to analyze the clinical data of 42 patients with cervical spine hyperextension in Shanghai Ninth People’s Hospital，Shanghai Jiaotong University School of Medicine from January 2016 to June 2019. There were 31 males and 11 females at age range of 40-78 years［（59.7 ± 9.9）years］. All patients underwent open-door laminoplasty.Preoperative Japanese Orthopaedic Association score（JOA）was（10.2 ± 3.8）points，and American Spinal Injury Association（ASIA）spinal cord injury score was（260.4 ± 47.5）points. Those with spinal cord occupation rate（SCOR）equal to or more than 70% were classified as spinal cord-canal mismatched group（n=21），and those with SCOR less than 70% were classified as spinal cord-canal matched group（n=21）. ASIA total score，ASIA upper and lower limb motor scores，ASIA sensory score，JOA score，surgical improvement rates and complications were compared between the two groups before operation，at postoperative one week and at the latest follow-up.Results:All patients were followed up for 12-26 months［（19.1 ± 2.3）months］. Both groups had significantly improved ASIA total score at postoperative one week and at the latest follow-up，compared with that before operation（ P < 0.05）. The two groups showed no significant difference in ASIA total score at postoperative one week（ P > 0.05）. ASIA total score in unmatched group was（307.6 ± 9.9）points at the latest follow-up，significantly lower than that in matched group［（315.4 ± 8.7）points］（ P < 0.01）. ASIA upper limb motor score in mismatched group was（29.1 ± 7.0）points and（36.6 ± 6.5）points at postoperative one week and at the latest follow-up，significantly lower than that in matched group［（42.0 ± 5.7）points，（47.4 ± 2.5）points］（ P < 0.01），while there was no significant difference in ASIA lower limb motor score and sensory score between the two groups（ P > 0.05）. Both groups showed significantly improved JOA score at postoperative one week and at the latest follow-up，compared with that before operation（ P < 0.05）. JOA score in mismatched group was（11.5 ± 3.0）points and（12.5 ± 3.0）points at postoperative one week and at the latest follow-up，significantly lower than that in matched group［（13.5 ± 2.4）points，（15.0 ± 2.0）points］（ P < 0.01）. Postoperative improvement rate in matched group was 95%（20/21），and was 85%（18/21）in mismatched group（ P < 0.05）. Cervical axial pain occurred in 3 patients in each group and C 5 nerve root palsy in 2 patients in matched group，all of which were relieved after conservative treatment. No implant loosening or breakage occurred during follow-up. Conclusions:Open-door laminoplasty can improve part of the nerve function of patients with cervical hyperextension injury. However，the overall improvement degree of nerve function especially recovery of upper limb motor function in patients with spinal cord-canal mismatch is inferior to those in spinal cord-canal matched patients.