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Objective:To evaluate spectral CT metal artifacts reduction (MAR) technique in reducing metal artifacts of spinal implants in a phantom.Methods:Ovine spines were chosen as anthropomorphic phantom. The phantom including the pedicle screws, 3D-printed vertebral body (VB) and mesh cage were examined using spectral CT. Postoperative CT images were reconstructed at 70—140 keV with 10 keV interval of MAR and non-MAR. Artifact index (AI) and signal-to-noise ratio (SNR) were evaluated by CT and SD values in ROIs around the implants. Visibility of bony structures, the artifacts of pedicle screw, 3D-printed VB and mesh cage were subjectively evaluated. Plotting curves of AI and SNR with the increasing keV were drawn. The AI and SNR were compared at lower (70 keV), medium (100 keV) and high (130 keV) level between MAR and non-MAR images using the paired t-test, and the subjective scores were compared using Wilcoxon signed rank-sum test. Results:The AI values around pedicle screws (anterior, posterior and lateral), 3D-printed VB and mesh cage decreased with the increase of keV, while SNR improved in MAR and non-MAR images. The AI values in the anterior, lateral and posterior pedicle screws and lateral titanium implants were significantly lower in MAR than those in non-MAR ( P<0.05). The AI value in posterior 3D-printed vertebral was lower in MAR than that of non-MAR only at 70 keV ( P<0.001). The SNR values in the anterior and posterior pedicle screws, 3D-printed VB increased with the increase of keV, but decreased in other ROIs. In the subjective evaluation, the image scores of MAR were higher than those of non-MAR ( P<0.05). Conclusion:Spectral CT using the MAR reconstruction can effectively reduce metal artifacts of spinal implants. The effect is better in pedicle screw and mesh cage than 3D-printed VB.
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BACKGROUND: Percutaneous kyphoplasty is of breakthrough significance in minimally invasive treatment of vertebral compression fractures, but it also has shortcomings, such as bone cement leakage, limited height recovery of the vertebral body, and increased risk of fracture of adjacent vertebral bodies. In recent years, a variety of spinal implants have been developed, and the application of these implants in the treatment of vertebral compression fractures in percutaneous kyphoplasty has achieved good clinical efficacy, and is beneficial to reduce the complications of traditional percutaneous kyphoplasty. OBJECTIVE: To describe the types and characteristics of various spinal implants and explore their clinical applications in percutaneous kyphoplasty. METHODS: CNKI, PubMed and Elsevier were retrieved for relevant literature. The key words were "percutaneous kyphoplasty, spinal implants, vertebral stents, vertebral compression fractures". Relevant articles published from January 2000 to June 2019 were reviewed, including review, basic research and clinical research. Preliminary screening was conducted by reading the article title and abstract, and the literatures with low relevance to the article topic were excluded. According to the inclusion and exclusion criteria, 62 articles were finally included for analysis. RESULTS AND CONCLUSION: (1) Spinal implants used in percutaneous kyphoplasty include VBS stent, Jack vertebra expander, SKY bone expander system, Osseofix system, SpineJack, KIVA system and memory alloy vertebral stent. (2) They are modified and developed on the basis of classic percutaneous kyphoplasty to achieve the same clinical efficacy while minimizing complications such as cement leakage, loss of vertebral height, and increased risk of adjacent vertebral body fracture.
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BACKGROUND:The patients receiving total knee arthroplasty are high in average age, and often accompanied with hypertension, diabetes and other basic diseases. Due to the poor physical conditions of the patients, perioperative hemorrhage becomes the important factor that affecting the safety of replacement. OBJECTIVE:To analyze perioperative hidden hemorrhage of primary total knee arthroplasty, and to explore the method of evaluating perioperative blood loss by osteoarthritis severity before total knee arthroplasty. METHODS:A retrospective analysis of 126 knee osteoarthritis patients undergoing total knee arthroplasty was conducted. Al the patients were divided into two groups according to Kel gren and Lawrecne imaging classification:stage Ⅲ group and stage Ⅳ group. The hidden hemorrhage of the patients in two groups was calculated. RESULTS AND CONCLUSION:The average total blood loss of the patients was 1 560 mL, included hidden hemorrhage 865 mL (55%). The mean blood loss of stage Ⅲ group was 1 290 mL with the mean hidden hemorrhage of 684 mL (53%). The mean blood loss of stage Ⅳ group was 1 644 mL with the mean hidden hemorrhage of 921 mL (56%). Statistical analysis showed there were significant differences of total blood loss and hidden hemorrhage between two groups (Phidden hemorrhage. The results indicate that higher grade of osteoarthritis imaging classification, the more of total blood loss and hidden hemorrhage, while the change of the percentage of hidden hemorrhage is not significant. Preoperative evaluation of patients’ blood loss by osteoarthritis severity has great significance for blood management and surgical safety of patients.
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BACKGROUND:Navigation assisted minimal y invasive posterior lumbar interbody fusion and pedicle screw fixation can precisely real-time guide a variety of operation under minimal y invasive sleeve, and implant the pedicle screws and interbody fusion cage and other implants safely and accurately, thus can determine the decompression parts. Minimal y invasive transforaminal lumbar interbody fusion is the typical approach in recent years for the successful application of minimal y invasive spine surgery techniques with the advantages of smal incision, less bleeding, slight tissue damage and faster recovery. OBJECTIVE:To evaluate the short-term effect of minimal y invasive transforaminal lumbar interbody fusion with real-time three-dimensional navigation system and open posterior transforaminal lumbar interbody fusion. METHODS:Forty cases with single-level lumbar disc herniation were retrospectively analyzed. The patients were treated with minimal y invasive transforaminal lumbar interbody fusion with real-time three-dimensional navigation system (20 cases) and open posterior transforaminal lumbar interbody fusion (20 cases) respectively for the comparative analysis. The fusion duration, intraoperative blood loss, postoperative drainage volume, the length of postoperative hospital stay and the length of hospital stay were compared between two groups. The wound pain and function were evaluated after treatment with visual analogue scale score and Japanese Orthopaedic Association score. RESULTS AND CONCLUSION:Al patients were fol owed-up for 7.7 months. The operative duration in the minimal y invasive transforaminal lumbar interbody fusion group was longer than that in the open posterior transforaminal lumbar interbody fusion group, and the difference was significant (P0.05).The results indicate that minimal y invasive transforaminal lumbar interbody fusion with real-time three-dimensional navigation system is an effective method for lumbar disc herniation with the advantages of less intraoperative blood loss, less postoperative drainage volume, smal trauma, short hospital stay and short-term efficacy.
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10.3969/j.issn.2095-4344.2013.26.006
ABSTRACT
10.3969/j.issn.2095-4344.2013.26.007