Objective:To evaluate the feasibility of the screw and plate for clival fixation using a transoral expanded approaches.Methods:The transoral expanded approaches were performed on craniocervical segment specimens obtained from 7 subjects, including transoral approach (TO), transoral with soft (TOP) or hard (TOHP) palate split, mandibulotomy (MO) and mandibuloglossotomy (MLO). The distribution and thickness of soft tissue, the configuration of the vertebral arteries, the distance between the midline and the vertebral arteries, the exposed area of the clivus and cervical spine, and the range of screw angle (the angle between the line from the lower incisor or the central base of the mandible to the exposed area of the clivus and the tangent line of the clivus) were evaluated.Results:The thickness of the soft tissue on the posterior pharyngeal wall above the clival pharyngeal nodules was 3.5±0.6 mm. That on the anterior C 1-C 5 vertebrae was 5.0±0.5 mm. The distances from the bilateral vertebral arteries to the midline was 19.5±1.2 mm at C 1, 2, 14.6±2.7 mm at C 2, 3, 14.0±2.7 mm at C 3, 4, and 13.9±2.7 mm at C 4, 5. For the TO approach, the longitudinal diameter of the exposed clivus was 8.3±3.0 mm. The distance from the lower incisor to the superior margin of the exposed clivus, the lower margin of the exposed clivus, the anterior arch of C 1, the vertebral body of C 2 and C 3 were 104.7±4.3 mm, 99.2±6.8 mm, 81.4±4.3 mm, 75.1±4.0 mm and 68.7±6.5 mm, respectively. Six specimens were exposed to the C 3, while one was exposed to the C 2. For the TOP approach, the longitudinal diameter of the exposed clivus was 18.5±4.8 mm. The distance from the lower incisor to the superior margin of the exposed clivus and the pharyngeal nodules were 107.9±6.7 mm and 104.8±6.7 mm, respectively. For the TOHP approach, the longitudinal diameter of the exposed clivus was 26.3±1.8 mm (the clival length) with distance from the lower incisor to the superior margin of the clivus 112.4±12.6 mm. For the MO/MLO approach, the entire clivus was exposed. The distance from the central base of the mandible to the superior and inferior margin of the exposed clivus and the pharyngeal nodules were 141.8±15.7 mm, 131.0±9.9 mm and 120.5±8.2 mm, respectively. The inferior margin of the exposed cervical vertebra was C 5, 6. The rate of the clival screw placement through anterior occipitocervical fixation using TO, TOP, TOHP, MO and MLO was 0%, 71% (5/7), 86% (6/7), and 100%, respectively. The screw angle was 99.0°±1.8°, 92.6°±7.7°, 92.6°±7.7°, 75.1°±7.7°, and 75.1°±7.7°, respectively. Conclusion:Occipitocervical fixation with clival screw and plate could be conducted in most cases via TOP and TOHP approaches. However, in some cases with small split-mouth or mouth opening limited, smaller clival screw angle caused by basilar impression or basilar invagination, requiring fixation and reconstruction of the lower cervical spine, and the MO/MLO approaches could be still required to achieve the fixation.

Extreme lateral interbody fusion (XLIF) can be used to treat various lumbar diseases, such as lumbar facet joints intervertebral disc herniation, spondylolisthesis, stenosis. Compared with other approaches, XLIF establishes the surgical channel behind the peritoneum through lateral abdomen, with the advantages of less blooding in the surgery, smaller invasion, lower complications rate and shorter rehabilitation period. Meanwhile，this technique can not only reduce the risk of vascular injury, but also avoid the damage of back structures，such as muscles and facet joints. Therefore, XLIF has been attracting more and more attention and application. However, there is no conclusive evidence to prove that XLIF is better than other surgical approaches in terms of clinical results and complications rates. This paper reviewed the effects of XLIF for reconstructing spinal stability, as well as its biomechanical properties compared with other classical surgeries.

Objective To compare biomechanical properties of cortical bone trajectory (CBT) screw and traditional trajectory screw for fixing upper-middle thoracic spine. Methods The tomography images were obtained by CT scanning of normal T7 and T8 segments, and the three-dimensional (3D) model of T7-8 was reconstructed by Mimics software. The finite element model of upper-middle thoracic spine was established by optimizing FreeForm model and pre-processing function of ANSYS software. On this basis, the CBT screw and pedicle screw fixation models after discectomy were established, and 5 N·m flexion, extension, lateral bending and rotation loads were applied to the two model groups, respectively. The displacement and peak stress of vertebrae and implants under different working conditions were compared and analyzed. Results Under different loading conditions, the maximum displacement of CBT screw group was lower than that of pedicle screw group, and the range of motion of CBT screw group was lower than that of pedicle screw group. The stress level of both models was close, and the stress of CBT screw group was slightly lower than that of pedicle screw group. Under the load of flexion, extension and rotation, the maximum vertebral stress of pedicle screw group decreased by 31%, 17% and 18% compared with that of CBT screw group, and under lateral bending load, the vertebral stress of CBT screw group was 20% lower than that of pedicle screw group. Under the load of flexion and rotation, the maximum stress of pedicle screw group decreased by 2% and 11%; however, the maximum stress of CBT screw group was 11% and 1% lower than that of pedicle screw group. Conclusions The stability of CBT screw was better than that of pedicle screw, and the overall stress distribution was similar to that of pedicle screw. However, the vertebral stress distribution of CBT group was slightly inferior. The research findings provide a theoretical basis for the clinical application of cortical screw fixation after the failure in pedicle screw fixation for the upper-middle thoracic vertebrae.

The stability of the occipitocervical region mainly depends on the integrity of the bony structure,surrounding ligaments and joint capsules.The instability of this region often leadsto the clinical symptoms of compression injury of nerve and vascular,which requires early surgical intervention to rebuild its stability.Posterior occipitocervical fixations are main surgical treatment for the occipitocervical diseases.However,the posterior fixations are not suitable for some patients with congenital or iatrogenic causes.Recently,the anterior occipitocervical fixation with the screws anchored at clivus or into the occipital condyles have been used for the following operations.1.Anterior bone graft fusion.One case which was performed by oral approach was reported well fusion,but the stability was poor and there was a possibility of displacement.2.Anterior shaped titanium cage and plate fixation.The literatures reported that this anterior operation was completed in 35 cases by oral,oral combined with mandibulotomy,and anterior retropharyngeal approaches.This fixation has a good biomechanical stability and is widely used in clinical applications,including occipitocervical tumors and deformities.And the complications including intraoperative vascular,spinal and dural injuries,postoperative drinking cough,non-fusion,deep infection,and death.3.Anterior occipital-atlantoaxial joint screw fixation.Seven cases were performed by anterior occipital-atlantoaxial joint screw fixation through anterior percutaneous approach.This fixation is less trauma,but required precise placement of screw and not conducive bone fusion,and it is suitable for traumatic instability of the upper cervical spine,atlantoaxial dislocation and basilar invagination.Each procedure of anterior occipitocervical fixation is not suitable for all patients,and it should be adopted according to the patient's condition,surgical hardware conditions and the surgeon's habits.

Objective To analyze the correlation of vertebral osteophyte and lumbar disc degeneration in the elderly people and explore the possible mechanism of osteophyte formation. Methods X-ray and MRI data of 120 elderly people with backache or leg pain were retrospectively analyzed. Osteophyte was classified into four grades by X-ray according to the method proposed by Nathan. Discs with osteophyte were defined as occurring when osteophyte of grade II or greater were present. Lumbar disc degeneration was classified into five grades by MRI according to the method proposed by Pfirrmann. The obtained parameters were statistically treated and analyzed. Results Osteophyte and age were positively correlated at every lumbar disc level (P < 0.05). The proportion of osteophyte in L3/4 (76.7%) and L4/5 (70.08%) were more severe than that in L1/2 (31.7%) and L2/3 (46.7%). Osteophyte and lumbar disc degeneration were positively correlated at every lumbar disc level (P < 0.01). Conclusion Osteophyte becomes more severe with the increasing of lumbar disc degeneration. The vertebral stress after lumbar disc degeneration may be the main cause of osteophyte.

Objective To establish rabbit model of scoliosis induced with stable asymmetric lumbar loads. Methods Scoliosis was induced in 10 two-month-old New Zealand rabbits using 316L stainless steel springs placed between the unilateral transverse processes of L2 and L5. Serial radiographs were documented before and at 1, 4, 8, 9 and 12 weeks after the operation. At weeks, the rabbits were randomly divided into SR group (n=5) with the spring removed and SK group (n=5) without spring removal. Results All the rabbits survived the experiment with Cobb angle all greater than 10°at the end of the experiment. Significant changes were found in the Cobb angles and kyphotic angles at 1, 4 and 8 weeks after the operation (P<0.05). At 8 weeks, the Cobb angle, the kyphotic angle and the length of the spring were similar between SR and SK groups (P>0.05), and in the 4 weeks following spring removal in SR group, the Cobb angle and the kyphosis decreased significantly compared with those in SK group (P<0.05). Micro-CT showed that the BV/TV of the concave side was greater than that of the convex side. The length of the spring did not show obvious changes during the experiment (P>0.05). Conclusion Asymmetric lumbar loading is a convenient, time-saving, and highly reproducible approach for establishing rabbit models of scoliosis.

Objective To establish rabbit model of scoliosis induced with stable asymmetric lumbar loads. Methods Scoliosis was induced in 10 two-month-old New Zealand rabbits using 316L stainless steel springs placed between the unilateral transverse processes of L2 and L5. Serial radiographs were documented before and at 1, 4, 8, 9 and 12 weeks after the operation. At weeks, the rabbits were randomly divided into SR group (n=5) with the spring removed and SK group (n=5) without spring removal. Results All the rabbits survived the experiment with Cobb angle all greater than 10°at the end of the experiment. Significant changes were found in the Cobb angles and kyphotic angles at 1, 4 and 8 weeks after the operation (P<0.05). At 8 weeks, the Cobb angle, the kyphotic angle and the length of the spring were similar between SR and SK groups (P>0.05), and in the 4 weeks following spring removal in SR group, the Cobb angle and the kyphosis decreased significantly compared with those in SK group (P<0.05). Micro-CT showed that the BV/TV of the concave side was greater than that of the convex side. The length of the spring did not show obvious changes during the experiment (P>0.05). Conclusion Asymmetric lumbar loading is a convenient, time-saving, and highly reproducible approach for establishing rabbit models of scoliosis.

BACKGROUND:A newly developed calcium phosphate/β-tricalcium phosphate composite bone cement with a negative surface charge (genex?) has been reported to possess osteoinductivity properties. However, to our knowledge, no previous literatures have reported genex? for vertebroplasty in the osteoporotic spine.
OBJECTIVE:To evaluate the biomechanical properties and osteogenesis of vertebral bodies injected with genex? cement in a rabbit vertebroplasty defect model.
METHODS:Thirty New Zealand rabbits were used to establish osteoporosis models. Four weeks after modeling, model rabbits had an iatrogenical y created cavitary lesion at L 3 and L 5 and were injected with either genex? cement (experimental group) or polymethyl methacrylate bone cement (control group). The L 1 vertebral body served as model group without treatment. After 3 and 6 months, 15 rats from each group were executed respectively, and three vertebral samples were taken for Micro-CT analysis and biomechanical tests.
RESULTS AND CONCLUSION:(1) The Micro-CT showed better three-dimensional structure parameters of the trabecular bone in the experimental group than the control group (P<0.05) after 3 months, which however had no difference from the model group (P>0.05). After 6 months, the structure parameters in the experimental group were superior to those in the control and model groups (P<0.05). (2) After 3 months, the vertebral body compression strength of the experimental group was lower than that of the control group (P<0.05), but higher than that in the model group (P<0.05). The vertebral stiffness of the experimental group was lower than that in control and model groups (P<0.05). After 6 months, the vertebral body compression strength of the experimental group was not different from that of the control group (P>0.05), but stil higher than that of the model group (P<0.05). The vertebral stiffness showed no difference between three groups (P>0.05). These findings indicate that genex? cement can rapidly repair osteoporotic vertebral defects and improve the bone strength. Verterbroplasty with genex? cement has adequate osteoinductivity, biocompatibility, and adequate compressive strength.

OBJECTIVETo conduct a clinical trial of ketogenic diet (KD) in patients with acute spinal cord injury (SCI) and evaluate its safety and feasibility by measuring blood ketone bodies and blood glucose levels.

METHODTen patients with acute SCI were recruited in the trial during the period from May, 2012 to October, 2013. The patients received a standard KD after fasting for 48 h. The levels of blood ketone, blood glucose and uric ketone were tested daily, and routine blood examination, electrolytes, liver and kidney function, body mass index (BMI), sensory and motor function, and adverse reactions were monitored weekly to assess the safety and feasibility of KD.

RESULTSKD treatment lasted for a mean of 12.9 days (4 to 29 days) in these patients. In all the patients, blood ketone level increased during the fasting and maintained a level above 2.0 mmol/L after taking KD, while the uric ketone level ranged from +++ to ++++. The blood glucose level was in the normal range during KD. Except for blood chloride level and BMI, routine blood test results, electrolytes, liver and kidney function showed no significant changes after KD. No significant changes were observed in the sensation of light touch and pinprick. The average motor ASIA score increased from 33.3 to 35.1 after KD. Gastrointestinal dysfunction (diarrhea, nausea, poor appetite, gastric pain, and abdominal distension) was recorded in 5 patients, hypoglycemia occurred in one patient early after KD, and one patient experienced urticaria during KD. All the adverse reactions were relieved after symptomatic treatments.

CONCLUSIONThis preliminary clinical trial demonstrated that KD could increase ketone bodies level and maintain a normal blood glucose level, suggesting its safety and feasibility in patients with acute SCI.

Adolescent ; Adult ; Aged ; Diet, Ketogenic ; adverse effects ; methods ; Feasibility Studies ; Female ; Humans ; Male ; Middle Aged ; Spinal Cord Injuries ; diet therapy ; Treatment Outcome ; Young Adult