BACKGROUND:The addition of traditional rod-rod fixation for atlantoaxial joint disease to C1-C2 pedicle screw-rod fixation(C1-C2 PSR)can provide stronger anti-rotation stability for screw/rod fixation,but there is a risk of installation difficulties,impact on bone graft bed,and spinal cord injury.The new horizontal screw-screw crosslink(hS-S CL)designed by the authors can effectively overcome the above shortcomings,but its biomechanical properties are unclear. OBJECTIVE:To analyze biomechanical properties of new horizontal screw-screw crosslink in C1-C2 PSR by three-dimensional finite element analysis. METHODS:CT thin layer scanning data were collected from the occipital base to the axis(C0-2)of one adult healthy male volunteer.The atlantoaxial finite element models were established respectively:the normal group,the unstable group,the non-crosslink group(unstable+C1-C2 PSR),and the crosslink group(C1-C2 PSR+hS-S CL).Range of motion and Von Miss Stresses in flexion and extension,lateral flexion and rotation of the four groups were calculated by applying 1.5 Nm torque to each finite element model,and the stress cloud was extracted. RESULTS AND CONCLUSION:(1)Range of motion of the unstable group was increased by 43.8%-78.7%compared with the normal group,and the range of motion of the internal fixation groups was 90.2%-98.7%lower than that of the unstable group under six conditions.The range of motion of the crosslink group and the non-crosslink group was basically the same in flexion and extension states,but in lateral flexion and rotation states,the range of motion of the crosslink group decreased 34.3%-43.8%and 78.6%-79.1%,respectively,compared with the non-crosslink group,and range of motion decreased most obviously in rotation state.(2)The stress peak of the internal plant model:The maximum stress of the crosslink group was generally smaller than that of the non-crosslink group,and the stress peak value of all the internal fixation groups was the lowest when the extension was carried out.(3)The stress cloud of internal plants showed that there was no obvious stress concentration phenomenon in the internal fixation,and the main stress distribution areas were the screw root and bone joint,and the crosslink ends were the screw tail groove or the joint rod joint.(4)The new horizontal screw-screw crosslink can obviously improve the anti-rotation stability of internal fixation and it can share part of the pressure in the three-dimensional motion direction of the internal fixation system and reduce the maximum stress of the internal plants.However,the stress distribution is obvious at both ends of the crosslink,and this part may be prone to fracture of the crosslink.

BACKGROUND:Posterior atlantoaxial pedicle screw rod internal fixation is the main method for treating atlantoaxial dislocation,and the horizontal crosslink plays an important role in the antirotation ability of the internal fixation system.The new horizontal screw-screw crosslink can effectively overcome the disadvantages of traditional horizontal crosslink,such as inconvenient installation,impact on bone grafting bed,and potential spinal cord injury.However,the biomechanical properties of the new horizontal screw-screw crosslink with different installation modes are still unclear. OBJECTIVE:To investigate the biomechanical characteristics of new different installation modes of horizontal screw-screw crosslink in the C1-C2 pedicle screw-rod fixation and to provide a theoretical basis for optimal installation mode. METHODS:Six fresh human occipitocervical specimens were divided into the intact state group(group A),and the atlantoaxial instability model of type Ⅱ odontoid fracture was established based on the intact state group as the instability group(group B).The C1-C2 pedicle screw-rod fixation was performed on each specimen based on the instability group(group C).In group C,different installation modes of horizontal screw-screw crosslink were successively installed in each specimen,including upper transverse connection(two atlas screw tails)as group D,lower transverse connection(two axis screw tails)as group E,diagonal transverse connection(upper left and lower right for group F,lower left and upper right for group G),and cross transverse connection as group H.The specimen models were tested in order of flexion,extension,lateral flexion and lateral rotation on a three-dimensional motion machine,and the atlantoaxial range of motion of each group of specimens was obtained.Repeated measure analysis of variance was used to evaluate the biomechanical properties of each group. RESULTS AND CONCLUSION:(1)Under six states,the range of motion of groups A,C,D,E,F,G and H was smaller than that of group B,and there were statistically significant differences(P＜0.05).(2)In the flexion and extension states,there was no significant difference among the five types of horizontal screw-screw crosslink groups(P＞0.05).(3)In the left and right rotation directions,there were significant differences in D and E groups compared with F,G and H groups(P＜0.05);there were no significant differences between D and E groups,and F and G groups(P＞0.05),and there were no significant differences in F and G groups compared with H group(P＞0.05).(4)In conclusion,under flexion-extension states,the biomechanical stability of five types of horizontal screw-screw crosslink groups was similar,but under the rotation state,the stability of diagonal horizontal screw-screw crosslink group and cross horizontal screw-screw crosslink group was obviously better than that of transverse horizontal screw-screw crosslink group;however,the stability of diagonal horizontal screw-screw crosslink group is similar to the cross horizontal screw-screw crosslink group,so the former is more worthy of clinical recommendation.

BACKGROUND:The pedicle navigation template has many advantages,but there are still some problems.For example,poor soft tissue dissection leads to poor adhesion of the pedicle navigation template,resulting in screw path deviation;careful dissection of soft tissue to fit the pedicle navigation template leads to prolonged surgery time and increased bleeding;the design of the pedicle navigation template cannot predict the vertebral rotation and the impact of body position changes,resulting in the poor fitting. OBJECTIVE:To explore the utility of a new 5-point positioning point-contact pedicle navigation template in the case of scoliosis and complex pedicle. METHODS:A total of 20 patients with scoliosis and complicated pedicle admitted to the Department of Spinal Surgery,Guizhou Hospital,Beijing Jishuitan Hospital from February 2020 to February 2023 were selected for scoliosis orthopedics.During the operation,the 5-point positioning point-contact pedicle navigation template was used to guide the screws.According to the inclusion and exclusion criteria,34 cases were matched as the empirical nail placement group,and conventional barehanded nail placement was performed.The time of placement,the amount of bleeding,the number of fluoroscopies,the number of manual diversions,the level and accuracy of pedicle screws,the complications of placement,and the rate of correction of main curvature were compared between the two groups. RESULTS AND CONCLUSION:(1)There were no significant differences in sex,age,coronal Cobb's angle of the main curvature,bending Cobb's angle of the main curvature,pedicle variation,apex rotation,fusion segment,number of screws,level of screws,accuracy of screws,and rate of correction of main curvature between the navigation template group and the empirical nail placement group(P>0.05).(2)Compared with the empirical nail placement group,the navigation template group had more advantages in time of placement(P=0.034),amount of bleeding(P=0.036),number of fluoroscopies(P=0.000)and number of manual diversions(P=0.021).(3)There were 0 cases of screw-related complications in both groups.(4)In conclusion,the 5-point positioning point-contact 3D printing pedicle navigation template has a claw-like structure.It can firmly adapt to various deformities of the lamina articular process,avoid drift,and accurately place the screws.It has a point-like contact lamina structure to avoid extensive and complete dissection of the posterior structure,and reduce bleeding,operation time,and trauma.Pre-designed screw entry points and directions can reduce the number of fluoroscopy and operation time.Segmental design can avoid discomfort due to changes in anesthesia position.The operation is simple and the accuracy of screw placement is high.

Retrograde adeno-associated viruses (AAVs) are capable of infecting the axons of projection neurons and serve as a powerful tool for the anatomical and functional characterization of neural networks. However, few retrograde AAV capsids have been shown to offer access to cortical projection neurons across different species and enable the manipulation of neural function in non-human primates (NHPs). Here, we report the development of a novel retrograde AAV capsid, AAV-DJ8R, which efficiently labeled cortical projection neurons after local administration into the striatum of mice and macaques. In addition, intrastriatally injected AAV-DJ8R mediated opsin expression in the mouse motor cortex and induced robust behavioral alterations. Moreover, AAV-DJ8R markedly increased motor cortical neuron firing upon optogenetic light stimulation after viral delivery into the macaque putamen. These data demonstrate the usefulness of AAV-DJ8R as an efficient retrograde tracer for cortical projection neurons in rodents and NHPs and indicate its suitability for use in conducting functional interrogations.
Animals ; Haplorhini ; Axons ; Motor Neurons ; Interneurons ; Macaca ; Dependovirus/genetics* ; Genetic Vectors

Objective:To explore the effect of a new 5-point positioning point contact clamping fixation pedicle navigation template in treating cases of scoliosis and complex pedicle.Methods:From February 2019 to February 2023, 30 patients with scoliosis and complicated pedicle were admitted for orthopedic surgery. There were 11 males and 19 females, with an average age of 16.54±6.23 years (range 7 to 35 years). A total 60 cases treated before February 2019 were matched as a control group, including 23 males and 37 females, with an average age of 16.72±6.34 years (range 6 to 35 years). During the operation, the 5-point positioning point-contact clamping fixation pedicle navigation template was used to guide the screws. Screw placement time, screw placement bleeding volume, fluoroscopy frequency, manual redirection frequency, Rao pedicle screw placement classification and accuracy, screw placement complications, and main curve correction rate were recorded.Results:All the 30 cases from the study group successfully underwent the surgery with a total of 354 screws placed, while in the control group a total of 727 screws were placed in 60 cases. The surgery times and intraoperative bleeding volumes for the study group and the control group were 279.45±57.72 min vs. 292.54±58.87 min and 921.57±371.32 ml vs. 932.83±376.65 ml with significant differences ( t=-2.13, P=0.022; t=-1.87, P=0.024). The time for screw placement from the start of skin incision to the placement of the last screw and the bleeding volume during screw placement in the study group and the control group was 82.87±24.46 min vs. 97.53±25.56 min and 72.25±43.66 ml vs. 106.53±61.22 ml with significant differences ( t=-2.66, P=0.031; t=-2.32, P=0.027). The screw placement fluoroscopy frequencies and manual redirection frequencies in the study group and the control group were 4.21±1.11 times vs. 6.32±1.81 times and 0.47±0.64 times vs. 0.93±0.86 times with significant differences ( t=-4.66, P<0.001; t=-2.78, P=0.018). According to the Rao pedicle screw placement classification, the study group had 329 screws classified as level I, 19 screws as level II, and 6 screws as level III. In the control group, there were 669 screws classified as level I, 45 screws as level II, 12 screws as level III, and 1 screw as level IV with no significant difference (χ 2=4.26, P=0.547). The screw placement accuracy and the main curve correction rate in the study group and the study group was 98.31%±3.10% vs. 98.21%±4.92% and 57.85%±9.46% vs. 6.64%±9.22% with no significant differences ( t=0.88, P=0.384; t=0.42, P=0.663). No complications of nerve damage, major vascular injury, cerebrospinal fluid leakage, infection, or death happened during surgery or postoperatively. There were no complications of internal fixation displacement, loosening, or breakage. The outcomes of the patients were good with significantly improved appearance and trunk balance after surgery. Conclusion:The new navigation template provided an accurate and safe way of placing screws in treating various deformities of the lamina articular process without extensive and complete dissection of the posterior structure, leading to reduced fluoroscopy and operation time.

OBJECTIVE: To explore the effectiveness of a new point contact pedicle navigation template (referred to as "new navigation template" for simplicity) in assisting screw implantation in scoliosis correction surgery. METHODS: Twenty-five patients with scoliosis, who met the selection criteria between February 2020 and February 2023, were selected as the trial group. During the scoliosis correction surgery, the three-dimensional printed new navigation template was used to assist in screw implantation. Fifty patients who had undergone screw implantation with traditional free-hand implantation technique between February 2019 and February 2023 were matched according to the inclusion and exclusion criteria as the control group. There was no significant difference between the two groups ( P>0.05) in terms of gender, age, disease duration, Cobb angle on the coronal plane of the main curve, Cobb angle at the Bending position of the main curve, the position of the apical vertebrae of the main curve, and the number of vertebrae with the pedicle diameter lower than 50%/75% of the national average, and the number of patients whose apical vertebrae rotation exceeded 40°. The number of fused vertebrae, the number of pedicle screws, the time of pedicle screw implantation, implant bleeding, fluoroscopy frequency, and manual diversion frequency were compared between the two groups. The occurrence of implant complications was observed. Based on the X-ray films at 2 weeks after operation, the pedicle screw grading was recorded, the accuracy of the implant and the main curvature correction rate were calculated. RESULTS: Both groups successfully completed the surgeries. Among them, the trial group implanted 267 screws and fused 177 vertebrae; the control group implanted 523 screws and fused 358 vertebrae. There was no significant difference between the two groups ( P>0.05) in terms of the number of fused vertebrae, the number of pedicle screws, the pedicle screw grading and accuracy, and the main curvature correction rate. However, the time of pedicle screw implantation, implant bleeding, fluoroscopy frequency, and manual diversion frequency were significantly lower in trial group than in control group ( P<0.05). There was no complications related to screws implantation during or after operation in the two groups. CONCLUSION The new navigation template is suitable for all kinds of deformed vertebral lamina and articular process, which not only improves the accuracy of screw implantation, but also reduces the difficulty of operation, shortens the operation time, and reduces intraoperative bleeding.
Humans ; Orthopedic Procedures ; Pedicle Screws ; Retrospective Studies ; Scoliosis/surgery* ; Spinal Fusion/methods* ; Spine ; Surgery, Computer-Assisted/methods*

Objective:To investigate the safety and clinical efficacy of osteotomy after halo pelvic traction in severe scoliosis accompanied with split cord malformation.Methods:The clinical data of 14 patients with severe scoliosis accompanied with split cord malformation admitted to the Department of Spinal Surgery, Guizhou Orthopedic Hospital from August 2015 to August 2019 were retrospectively analyzed.There were 6 males and 8 females, aged (19.8±5.0) years (range:13 to 34 years). All patients received spinal orthopedic surgery after halo pelvic traction for 3 to 7 weeks.The data of traction time, height, Cobb angle in the main curved coronal plane and sagittal plane, lung function and nutritional status of the patient were collected before and after the treatment. Paired t test was used to compare the evaluation indexes. Results:The traction time of the 14 patients was (35.2±8.3)days (range:20 to 49 days), and the height of them increased from (156.7±7.6)cm (range:141 to 166 cm) before traction to (167.0±6.4)cm (range:154 to 177 cm) after traction（ t=-10.49， P<0.01）. The Cobb angle on the main curved coronal plane decreased from (117.4±17.2) ° (range: 91°to 176°) before traction to (56.4±8.1) ° (range:44°to 68°) after traction（ t=13.90， P<0.01）. The sagittal Cobb angle decreased from (92.5±11.6) ° (range:62°to 132°) before traction to (41.7±7.7) °(range:29°to 51°) after traction（ t=12.11， P<0.01）. No complications such as loosening of nailing and infection occurred during traction, and no decrease of nerve function occurred. Nine patients underwent single segment acromial transpedicle osteotomy and five underwent double segment adjacent asymmetric shortening osteotomy. None of the patients underwent longitudinal fracture resection. The lung function and nutritional status were improved after traction and surgery(all P<0.01). Postoperative follow-up was (22.5±9.1)months (range:12 to 36 months). At the last follow-up, the coronal Cobb angle was (56.3±7.1) °, and the sagittal Cobb angle was (37.7±6.5) °, showing no statistically significant difference from the angle after traction( t=0.16, P=0.88; t=2.28, P=0.32). There was no loss of orthopedic angle. None of the patients had internal fixation displacement, loosening or fracture. Conclusion:The treatment of severe scoliosis with accompanied with split cord malformation by halo pelvic traction is safe and effective, which is worthy of further confirmation by large sample study.

Objective:To investigate the safety and clinical efficacy of osteotomy after halo pelvic traction in severe scoliosis accompanied with split cord malformation.Methods:The clinical data of 14 patients with severe scoliosis accompanied with split cord malformation admitted to the Department of Spinal Surgery, Guizhou Orthopedic Hospital from August 2015 to August 2019 were retrospectively analyzed.There were 6 males and 8 females, aged (19.8±5.0) years (range:13 to 34 years). All patients received spinal orthopedic surgery after halo pelvic traction for 3 to 7 weeks.The data of traction time, height, Cobb angle in the main curved coronal plane and sagittal plane, lung function and nutritional status of the patient were collected before and after the treatment. Paired t test was used to compare the evaluation indexes. Results:The traction time of the 14 patients was (35.2±8.3)days (range:20 to 49 days), and the height of them increased from (156.7±7.6)cm (range:141 to 166 cm) before traction to (167.0±6.4)cm (range:154 to 177 cm) after traction（ t=-10.49， P<0.01）. The Cobb angle on the main curved coronal plane decreased from (117.4±17.2) ° (range: 91°to 176°) before traction to (56.4±8.1) ° (range:44°to 68°) after traction（ t=13.90， P<0.01）. The sagittal Cobb angle decreased from (92.5±11.6) ° (range:62°to 132°) before traction to (41.7±7.7) °(range:29°to 51°) after traction（ t=12.11， P<0.01）. No complications such as loosening of nailing and infection occurred during traction, and no decrease of nerve function occurred. Nine patients underwent single segment acromial transpedicle osteotomy and five underwent double segment adjacent asymmetric shortening osteotomy. None of the patients underwent longitudinal fracture resection. The lung function and nutritional status were improved after traction and surgery(all P<0.01). Postoperative follow-up was (22.5±9.1)months (range:12 to 36 months). At the last follow-up, the coronal Cobb angle was (56.3±7.1) °, and the sagittal Cobb angle was (37.7±6.5) °, showing no statistically significant difference from the angle after traction( t=0.16, P=0.88; t=2.28, P=0.32). There was no loss of orthopedic angle. None of the patients had internal fixation displacement, loosening or fracture. Conclusion:The treatment of severe scoliosis with accompanied with split cord malformation by halo pelvic traction is safe and effective, which is worthy of further confirmation by large sample study.

Objective To observe any effect of hyperbaric oxygen therapy on cognitive dysfunction caused by traumatic brain injury,and to explore possible neural mechanisms.Methods Sixty-four patients with cognitive impairment after a traumatic brain injury were randomly divided into a hyperbaric oxygen group (n =32) and a control group (n=32) using a random number table.Both groups accepted routine medical therapy and cognitive rehabilitation training,but the hyperbaric oxygen group additionally received hyperbaric oxygen treatment.Both groups' cognitive functioning was assessed using the Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) before and after the treatment.Fifteen patients were randomly selected from both groups to receive T1WI and diffusion tensor imaging scans.The correlation between the two evaluation resuhs was analyzed.Results After the intervention,improvement was observed in the average MMSE and MoCA scores of both groups,with the improvement in both average scores in the hyperbaric oxygen group significantly greater than among the control group.There was no significant correlation between the fractional anisotropy (FA) values of damaged white matter and the average MMSE or MoCA score in the controi group,but in the hyperbaric oxygen group there were significant positive correlations between the FA values of the corpus callosum,the anterior limb of the internal capsule and the left superior longitudinal fasciculus and the average MMSE and MoCA scores.Conclusions Hyperbaric oxygen therapy combined with rehabilitation training can further improve cognition after a traumatic brain injury.This is probably due to its adjusting the structure and function of the corpus callosum,of the anterior limb of the internal capsule and of the left superior longitudinal fasciculus.

Objective To explore the mechanisms of ligament of Marshall (LOM) initiat and sustain atrial fibrillation (AF).Methods The electrophysiologic properties of canine LOM were investigated using multipolar catheter mapping(normal canines,n =4,group A;AF canines,n =5,group B).The programmed stimulation were performed in the LOM,PV-left atrium(LA)junction and LA,respectively.Activations maps of LOM were analyzed from episodes of spontaneous onset of AF and initiation of induced AF by a single extrastimulus.The effectives refractory period of each part was compared and statistically analyzed among three parts in each group and between the two groups.LOM were cutted with surgical incision technology.The inducing rate of AF and the mapping rate of double potential and fragmented electrocardiogram were compared and statistically analyzed pro and post isolation of LOM.Results The incidence of abnormal potential of LOM in the two groups was significantly different(P ＜0.01),re-entry cycle(group A 25％ vs.B group 80％),tachycardia(group A 25％ vs.B 100％),double potential(group A 25％ vs.group B 80％),fragmentation potential(group A 25％ vs.group 80％).There was a significant difference in the rate of LOM tachycardia induction before and after LOM intervention in group B (P ＜ 0.05,before 100％ vs.after 20％).Conclusion There are two possible mechanisms of LOM involved in the occurrence and maintenance of AF:one is that LOM induces AF through spontaneous excitation,the other is that LOM participates in the reentry of left atrium and pulmonary vein in the form of bypass to induce and maintain AF.