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Background: Many techniques for atlantoaxial fixation have been developed. However, the biomechanical differences among various atlantoaxial fixation methods remain unclear. This study aimed to evaluate the biomechanical influence of anterior and posterior atlantoaxial fixation techniques on fixed and nonfixed segments., Methods: An occiput-C7 cervical finite element model was used to construct 6 surgical models including a Harms plate, a transoral atlantoaxial reduction plate (TARP), an anterior transarticular screw (ATS), a Magerl screw, a posterior screw-plate, and a screw-rod system. Range of motion (ROM), facet joint force (FJF), disc stress, screw stress, and bone-screw interface stress were calculated., Results: The C1/2 ROMs were relatively small in the ATS and Magerl screw models under all loading directions except for extension (0.1°-1.0°). The posterior screw-plate system and screw-rod system generated greater stresses on the screws (77.6-1018.1 MPa) and bone-screw interfaces (58.3-499.0 MPa). The Harms plate and TARP models had relatively small ROMs (3.2°-17.6°), disc stress (1.3-7.6 MPa), and FJF (3.3-106.8 N) at the nonfixed segments. Changes in disc stress and FJF of the cervical segments were not consistent with changes in ROM., Conclusions: ATS and Magerl screws may provide good atlantoaxial stability. The posterior screw-rod system and screw-plate system may have higher risks of screw loosening and breakage. The Harms plate and TARP model may more effectively relieve nonfixed segment degeneration than other techniques. The C0/1 or C2/3 segment may not be more susceptible to degeneration than other nonfixed segments after C1/2 fixation., (© 2023. The Author(s).)

Bone scaffolds designed based on the Voronoi-tessellation algorithm have been increasingly studied owing to their structural similarity with natural cancellous bone. The irregularity of pore morphology (IPM) influences the osteogenesis efficiency of Voronoi scaffolds since it may alter the static and hydromechanical microenvironments for the initial adhesion and mechano-regulated osteoblast differentiation (MrOD) of mesenchymal stem cells (MSCs). In this work, animal experiments were conducted to explore the relationship between IPM and osteogenesis efficiency in Voronoi scaffolds. A computational fluid dynamics (CFD) analysis based on discrete phase models was performed to predict the efficiency of MSC adhesion in different IPMs. Another combined finite element and CFD analysis based on the mechano-regulation algorithm was performed to predict the influence of IPM on the MrOD of the adhesive MSCs. The results showed that the osteogenesis efficiency of the Voronoi scaffolds increased as the IPM rose from low to moderate and then dropped as the IPM further rose. Same trends were also found in the MSC adhesion and MrOD, which caused by the changes of strain tensors on the strut surface and the tortuosity and fluid velocity of the fluid pathway. Moderate IPM induced the highest osteogenesis efficiency owing to its highest efficiencies of MSC adhesion and MrOD. This work identified the optimal IPM for the osteogenesis of Voronoi scaffolds and clarified its biomechanical mechanisms from the adhesion and mechano-regulated differentiation of MSCs, which is of great importance for guiding Voronoi scaffold design when it is used for bone defect repair., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Study Design: A biomechanical in vitro investigation., Objective: To evaluate the function and stability of self-designed biomimetic artificial atlanto-odontoid joint (BAAOJ) replacement on the atlantoaxial joint., Summary of Background Data: Upper cervical fusion surgery is a common treatment for various atlantoaxial disorders, and favorable clinical outcome has been achieved. However, the fusion surgery results in loss of atlantoaxial motion as well as adjacent segments degeneration, reducing the quality of life of patients and might produce severe neurological symptoms. Non-fusion technology is expected to solve the above problems, but various designed devices have certain defects and are still in the exploratory phase., Materials and Methods: Biomechanical tests were conducted on 10 fresh human cadaveric craniocervical specimens in the following sequence: 1) intact condition, 2) after the BAAOJ arthroplasty, 3) after BAAOJ fatigue test, 4) after odontoidect-omy, and 5) after anterior rigid plate fixation. Three-dimensional movements of the C1-C2 segment were evaluated to investigate the function and stability of BAAOJ arthroplasty compared with the intact condition after the BAAOJ fatigue test, odontoidect-omy, and rigid plate fixation., Results: Comparing the BAAOJ implantation to the intact state, the range of motion and neutral zone were slightly reduced in all directions (P > 0.05). Compared with the rigid plate fixation, the BAAOJ implantation significantly increased the range of motion and neutral zone in all directions, especially in the axial rotation (P < 0.05)., Conclusion: We designed a BAAOJ for correcting atlantoaxial disorders arising from atlantoaxial instability. As a non-fusion device, the most critical feature of BAAOJ replacement is the retention of flexion-extension, lateral bending, and axial rotation range of motion similar to the normal state. It can also stabilize the atlantoaxial complex, and the BAAOJ itself has a good initial stability.Level of Evidence: 4., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc.)

Purpose: Due to the high perforation rate of cervical pedicle screw placement, we have designed four different types of rapid prototyping navigation templates to enhance the accuracy of cervical pedicle screw placement., Methods: Fifteen human cadaveric cervical spines from C2 to C7 were randomly divided into five groups, with three specimens in each group. The diameter of pedicle screw used in this study was 3.5 mm. Groups 1-4 were assisted by the two-level template, one-level bilateral template, one-level unilateral template and one-level point-contact template, respectively. Group 5 was without any navigation template. After the surgery, the accuracy of screw placement in the five groups was evaluated using postoperative computed tomographic scans to observe whether the screw breached the pedicle cortex., Results: A total of 180 pedicle screws were inserted without any accidents. The accuracy rate was 75%, 100%, 100%, 91.7%, and 63.9%, respectively, from Groups 1 to 5. All the template groups were significantly higher than Group 5, though the two-level navigation template group was significantly lower than the other three template groups. The operation time was 4.72 ± 0.28, 4.81 ± 0.29, 5.03 ± 0.35, 8.42 ± 0.36, and 10.05 ± 0.52 min, respectively, from Groups 1 to 5. The no template and point-contact procedures were significantly more time-consuming than the template procedures., Conclusion: This study demonstrated that four different design types of navigation templates achieved a higher accuracy in assisting cervical pedicle screw placement than no template insertion. However, the two-level template's accuracy was the lowest compared to the other three templates. Meanwhile, these templates avoided fluoroscopy during the surgery and decreased the operation time. It is always very challenging to translate cadaveric studies to clinical practice. Hence, the one-level bilateral, unilateral, and point-contact navigation templates designed by us need to be meticulously tested to verify their accuracy and safety.

BACKGROUND Anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) are effective treatments for cervical spondylotic myelopathy (CSM), but it is unclear which is better. In this study, we compared the biomechanical properties of 2-level ACDF and 1-level ACCF. MATERIAL AND METHODS An intact C3-C7 cervical spine model was developed and validated, then ACDF and ACCF simulation models were developed. We imposed 1.0 Nm moments and displacement-controlled loading on the C3 superior endplate. The range of motions (ROMs) of surgical and adjacent segments and von Mises stresses on endplates, fixation systems, bone-screw interfaces, and bone grafts were recorded. RESULTS ACDF and ACCF significantly reduced the surgical segmental ROMs to the same extent. ACCF induced much lower stress peaks in the fixation system and bone-screw interfaces and higher stress peaks on the bone graft. ACDF induced much lower stress peaks on the C4 inferior endplate and equivalent stress on the C6 superior endplate. There was no difference in the ROMs of surgical and adjacent segments and the intradiscal stress of adjacent levels between ACDF and ACCF. CONCLUSIONS Both ACDF and ACCF can provide satisfactory spinal stability. ACDF may be beneficial for subsidence resistance due to the lower stress peaks on the endplate. The ACCF may perform better in long-term stability and bone fusion owing to the lower stress peaks in the fixation system and bone-screw interfaces, and higher stress peaks in the bone graft.

Study Design: This study tested the biomechanics of artificial atlantoodontoid joint replacement (AAOJR) in a dog model. Dogs were divided into the artificial AAOJR group (n=10), the decompression group (n=10), and the healthy control group (n=10) using a random number table., Objective: To evaluate whether the use of AAOJR for repair of atlantoaxial instability retains rotation and restores stability., Summary of Background Data: Atlantoaxial instability is characterized by excessive movement or laxity at the junction between the atlas (C1) and axis (C2). Pure decompression can lead to considerable loss of head and neck rotation and postoperative impairment. A series of biomechanical tests on cadavers found that the artificial AAOJR might rebuild the stability and retain the rotation function., Methods: We designed the AAOJ based on the radiologic and anatomic data of the dog atlas and axis, and established an animal model by resecting the odontoid and implanting the AAOJ into dogs. The biomechanical experiments measured the range of motion (ROM), neutral zone (NZ), and stiffness of flexion, extension, lateral bending, and axial rotation in the intact state, the decompressed state, after AAOJR, and after a fatigue test., Results: Compared with the intact state, after decompression operation, ROM and NZ in all directions, and stiffness during flexion were increased, and stiffness in all other directions was decreased. Compared with the after decompression state, AAOJR before and after the fatigue test resulted in decreased ROM in all directions (all P<0.05), decreased NZ during flexion/extension and lateral bending (all P<0.05), an increased NZ during axial rotation (both P<0.05), and increased stiffness in all directions (all P<0.05)., Conclusions: These results indicate that AAOJR could reconstruct the vertebral stability of the C1-C2 segment and retain some axial rotation function.

Purpose: We aimed to provide evidence for clinical choice of surgical approach in treating spinal tuberculosis, including anterior, posterior and combined approaches (combined anterior and posterior approach)., Methods: A literature search up to June 2015 was performed on PubMed, Embase, Cochrane library, CNKI, Wanfang and Weipu database. Weighted mean differences (WMDs) or risk radios (RRs) and their 95 % confidence intervals (CI) were calculated., Results: Total 26 studies with 2345 spinal tuberculosis adults were analyzed. Results showed advantages of posterior approach compared with anterior approach in operation time (WMD = 20.91; 95 % CI: 9.05-32.76), blood loss (WMD = 72.32, 95 % CI: 13.87-130.78), correction of angle (WMD = -2.47; 95 % CI: -4.04 to -0.90) and complications (RR = 1.78; 95 % CI: 1.21-2.60), and compared with combined approach in operation time (WMD = -82.76; 95 % CI: -94.38 to -71.14), blood loss (WMD = -263.63; 95 % CI: -336.85 to -190.41), hospital stay [(WMD = -4.60; 95 % CI: -5.10 to -4.10) and complications (RR = 0.36; 95 % CI: 0.23-0.58]. Meanwhile, significantly larger correction of angle (WMD = -2.25; 95 % CI: -4.35 to -0.14; P = 0.04) and less loss of correction (WMD = 3.97; 95 % CI: 2.22-5.72) were found when compared combined approach with anterior approach. However, combined approach had significantly longer operation time (WMD = -41.92; 95 % CI: -52.45 to -31.38) and more blood loss (WMD = -102.18; 95 % CI: -160.45 to -43.91) than anterior approach., Conclusion: Posterior approach has better clinical outcomes than anterior or combined approach for spinal tuberculosis. However, individual assessment of each case should be considered in the clinical application of these surgical approaches.

Background: Traumatic neuromas are rare benign tumors, which are common in trauma or post-operation and accompanied with obvious symptoms of pain. This study will show the superficial peroneal nerve neuroma occurring after resection of hemangioma., Case Presentation: A 44-year-old male had an operation of the right leg cavernous hemangioma resection in 1995. Half a year after the operation, pain around the wound appeared and gradually aggravated. The patient had the lesion exploration resection in 2013, and the pathological result showed traumatic neuroma. Within half a year of the second operation, severe pain showed up again, so neuroma resection proceeded in May 2015. The postoperative pathological and immunohistochemical results showed traumatic neuroma. According to the postoperative follow-up, there were no symptoms of pain appearing again., Literature Review: The pain is obvious, and B ultrasonography is the most efficient way to find neuromas. Both conservative and operative therapy have their advantages and disadvantages., Conclusions: There remain many unanswered questions in relation to the treatment of traumatic neuromas, and further research is required, although we have already had adequate understanding of traumatic neuromas.

The aim of the present study was to determine whether hyaluronic acid (HA) or physical therapy agents (PTA) can improve functional parameters in patients with knee Kashin-Beck disease (KBD). For 2 years, patients (n=55) were treated with HA weekly for 5 weeks, then received 6th and 7th injections on the 3rd and 6th month, respectively, for 7 injections in total. Patients (n=53) were treated with PTA five times a week for 3 weeks every month for 6 months. The patients were evaluated with the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and the visual analog pain scale (VAS). Trial registration, ChiCTR-TRC-12002189 (http://www.chictr.org/). During the study, following treatment interruption, pain increased in the PTA group (from a mean value of 85.7±83.8 mm at month 12 to 145.2±128.8 mm at month 18 and 201.3±150.5 mm at month 24), while it remained stable in the HA group (from a mean value of 80.7±70.6 mm at month 12 to 90.1±95.2 mm at month 18 and 82.6±85.3 mm at month 24), with a statistically significant difference in favor of HA at month 18 (P<0.05) and month 24 (P<0.05). Joint stiffness, physical function and total WOMAC showed the same trend as pain. The global efficacy judgments by the patients and the investigators showed a statistically significant difference in favor of HA at month 18 (P<0.05) and month 24 (P<0.05). In conclusion, although all the patients improved in terms of pain and function, HA was superior to PTA alone for pain relief and lasting effect.

Non-small cell lung cancer (NSCLC) is the most common type of lung tumor with poor prognosis, in which the Notch signaling pathway plays an important role. Notch activation complex kinase (NACK) has been reported both as a co-activator and a target gene of the Notch pathway. However, the molecular mechanism of NACK in NSCLC still remains unknown. In this study, the expression of NACK was analyzed in 35 paired NSCLC tumor samples and 2 NSCLC cell lines. MTT assay, cell migration assay, cell invasion assay, flow cytometry assay, and xenograft model were employed to detect the effect of NACK knockdown on the cell proliferation, metastasis, invasion and apoptosis of NSCLC. The relationship between NACK and Notch1 signaling pathway in NSCLC cells was assessed by western blot and luciferase reporter assay. We found that the expression of NACK in the NSCLC tissues and lung cancer cells were significantly increased. High level of NACK expression is remarkable associated with tumor differentiation, lymphatic metastasis, clinical stage and poor survival prognosis. The interference of NACK significantly inhibited cell proliferation, invasion and metastasis through inducing apoptosis in NSCLC cells. The transcriptional activity of related Notch1 target genes were significantly suppressed resulting from NACK knockdown. This study demonstrates that interference of NACK inhibits NSCLC progression through Notch1 signaling pathway and targeting NACK may be an effective approach for NSCLC therapy.

The present study aimed to analyze the indications, feasibility, safety and clinical effects of total spondylectomy and spine reconstruction through posterior or combined anterior-posterior approaches for thoracic lumbar and sacral vertebrae tumors. Between December 2009 and May 2012, 10 patients with thoracic lumbar and sacral vertebrae tumors were retrospectively analyzed. Different surgical indications and approaches were used according to the affected segments, the extent of lesion involvement and the specific pathology results. One-stage posterior or combined anterior-posterior total spondylectomy and reconstruction was used for the treatment of complicated thoracic lumbar and sacral vertebral malignant tumors and invasive benign tumors. The duration of surgery, levels of intraoperative blood loss and transfusions, and the clinical effects were observed. The average surgical duration was 6.8 h (range, 4.8-12 h), with an average blood loss level of 3,200 ml (range, 1,500-10,000 ml) and an average transfusion level of 2,500 ml. During the average 15 months (range, 3-29 months) follow up, two patients succumbed and one patient experienced tumor recurrence. Neither tumor reoccurrence nor metastasis was observed in all other patients. Personalized surgical indications and approaches according to the affected segments, the extent of lesion involvement and the specific pathology results would aid in the reduction of pain, the improvement of nerve function and the reduction of tumor recurrence.

Background: The aim of our study was to evaluate the clinical efficacy of posterior vs. anterior instrumentation for the treatment of spinal tuberculosis in adults., Methods: The electronic databases such as PubMed, MEDLINE, Springer, EMBASE, Google scholar, and Cochrane library were searched to select the potentially relevant reports that compared the efficacy of posterior instrumentation group (group A) with anterior instrumentation group (group B) in the treatment of spinal tuberculosis. Outcome assessments were correction of angle, loss of correction, fusion rate of the grafting bone, and complications after surgery., Results: This meta-analysis included four trials published between 2006 and 2012, involving 291 adult patients (group A, 154; group B, 137) with spinal tuberculosis. The overall meta-analysis showed that there were no significant differences (P>0.01) between group A and group B in correction of angle and loss of correction at final follow-up after operation The pooled WMD (weighted mean difference) of group A and group B was 2.85 (95% CI (confidence interval) = -1.25~6.94) and 1.14 (95% CI=-3.07~5.34), respectively. Besides, no significant differences (P>0.01) were observed in fusion rate of the grafting bone and complications after operation between group A and group B, and the pooled ORs (odds ratio) were 0.65 (95% CI=-0.23~1.85) and (95% CI=-0.19~1.50), respectively., Conclusions: Our results suggested that the posterior instrumentation appeared to have the same clinical outcome with the anterior instrumentation in the treatment of the adult patients with spinal tuberculosis.