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find Keyword "screw" 242 results
  • Efficacy of robot-assisted pedicle screw placement: an overview of systematic review

    ObjectiveTo re-evaluate the systematic review and meta-analysis (SR/MAs) of the efficacy of robot-assisted pedicle screw placement. MethodsThe CNKI, VIP, WanFang Data, SinoMed, PubMed, Embase, Cochrane Library, and Web of Science databases were electronically searched to collect SR/MAs of robot-assisted pedicle screw placement from inception to April 28, 2023. Two reviewers independently screened literature, extracted data and then assessed the quality of reports, methodological quality, risk of bias, and the strength of evidence quality by using PRISMA, AMSTAR-Ⅱ, ROBIS, and GRADE tool. ResultsA total of 20 SR/MAs were included. The results of the included studies showed that robot-assisted pedicle screw placement was more accurate and had a lower number of complications compared with freehand pedicle screw placement. The quality of reports, methodology, and evidence for pedicle screw placement efficiency in all SR/MAs were low or extremely low, with a high risk of bias. The main reasons included high heterogeneity of included studies, unclear research methods and selection criteria, and missing key reporting processes. ConclusionRobot-assisted pedicle screw placement may have better clinical efficiency than traditional freehand pedicle screw placement. But the quality of relational SR/MAs is low.

    Release date:2024-06-18 09:28 Export PDF Favorites Scan
  • AN IN VITRO BIOMECHANICAL EVALUATION OF EFFECT OF AUGMENTATION PEDICLE SCREW FIXATION WITH POLYMETHYLMETHACRYLATE ON OSTEOPOROTIC SPINE STABILITY

    Objective To ascertain whether augmentation pedicle screw fixation with polymethylmethacrylate (PMMA) can enhance the stability of unstable thoracolumbar burst fractures of osteoporotic spine. Methods Six fresh frozen female osteoporotic spines (T10-L5) were harvested and an anterior and posterior columnunstable model of L1 was made. Each specimen was fixated with plate and the stability test were performed by flexion, extension, axial rotation and lateral bending. The test of fatigue was done with MTS 858.The tests were repeated after screws were augmented with PMMA. To compare the biomechanical stability of 6 different conditions:○anormal specimens(control), ○bdefectmodel fixed with plate, not augmented and not fatigued, ○cafter fatigued, not augmented, ○dscrews augmented with PMMA, not fatigued, ○e after augmented and fatigued. ResultsIn ○b,○d and ○e conditions, the ranges of motion(ROM) were 6.23±1.56,4.49±1.00,4.46±1.83 inflexion and 6.60±1.80,4.41±0.82,4.46±1.83 in extension. There was no significant difference (Pgt;0.05), they were significantly smaller than those in ○a and ○c conditions (8.75±1.88,1.47±2.25 and 8.92±2.97,12.24±3.08) (Plt;0.01).Conclusion The results demonstrated that augmentation pedicle screws fixation with PMMA can increase the stability of osteoporotic spine.

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  • CERVICAL LATERAL MASS PLATE WITH ITS CLINICAL APPLICATION

    Objective To evaluate the fixation technique of using the cervical lateral mass plate in the cervical posterior approach operation. Methods Eight patients in this group were admitted from September 2001 to November 2006. Among the 8 patients, there were 6 males and 2 females, with their ages ranging from 28 to 78 years. Cervical vertebral fracture with dislocation was found in 4 patients, C2 spinal cord injury in 1, C1 fracture in 1, cervical spinal stenosis in 1, and C2-5 spinal cord neurofibroma in 1. Muscle strength 3-4. TheFrankel grading system was usedin 6 patients with traumatic injury. Before operation, Grade C was observed in 2patients,Grade D in 3,and Grade E in 1. All the operations were performed according to requirements of the Margel’s method. We positioned 40 screws in all the patients, including 4 screws at C2,6 screws at C3,12 screws at C4,4 screws at C5,4 screws at C6,2 screws at C7,and 6 screws at T1. Results The followingup for an average of 14.1 months (range,645 months) revealed that there was no malposition of the screws in the patients. One of the 8 patients developed spinal instability in the fixed segment at 3 months after operation. The headchestbrace was applied to the patient for 3 months, and the spinal fusion was achieved. The further followingup to 45 months indicated that there was no instability occurring. The remaining patients recovered to their spinal stability by the spinal fusion. The patients also recovered in their neurological function after operation. The Frankel assessment showed that 1 patient had Grade E, 3 from Grade D to Grade E, 1 from Grade C to Grade D, and 1 from Grade C to Grade E. Conclusion The cervical lateral mass plate fixation can provide the immediate and b segmental immobilization for the good cervical spine stability.

    Release date:2016-09-01 09:20 Export PDF Favorites Scan
  • BIOMECHANICAL RESEARCH OF LESS INVASIVE STABILIZATION SYSTEM AND DYNAMIC CONDYLAR SCREW IN FIXING SUBTROCHANTERIC FRACTURES OF FEMUR

    Objective To compare the biomechanical characteristics of the less invasive stabilization system (LISS) and the dynamic condylar screw (DCS) in the fixation of subtrochanteric fractures of the femur so as to provide theoretical basis for choosing internal fixator in clinical application. Methods Twelve cadaveric human femurs (35-50 years old) were selected with similar proximal femur, excluding deformities, fractures, and other lesions. The twelve femur specimens were randomly divided into 2 groups, 6 specimens per group. An 1 cm gap of osteotomy model was made in the proximal femur up to 1 cm below the lesser trochanter to simulate a comminuted subtrochanteric fracture of femur, and the distal end was embedded with denture acrylic and liquid for denture acrylic. Fracture was fixed by LISS in group A, and was fixed by DCS in group B. The specimens were fixed on Instron-8874 servo-hydraulic mechanical testing machine in a single-leg standing position, and the axial compression test and dynamic fatigue test were carried out to compare the compressive strength and the strain distribution at both sides of the fracture line. Results Axial compression test: the strain values of the 2 strain gauges in group A were significantly smaller than those in group B (P lt; 0.01); the vertical down displacement of the femoral head in group A was significantly smaller than that in group B (P lt; 0.01) under the same load; when the load was 600 N, the axial rigidity of group A was (209.06 ± 18.63) N/mm, which was significantly higher than that of group B [(65.79 ± 7.26) N/mm] (t=3.787, P=0.004). Dynamic fatigue test: the vertical down displacement of the femoral head in group A was significantly smaller than that in group B in the same cyclic loading cycle (P lt; 0.01); when the vertical down displacement of the femoral head was 0.5 mm, the force and the cyclic loading cycles in group A were significantly larger than those in group B (P lt; 0.01). Conclusion LISS, which has good mechanical stability, can meet the requirements for subtrochanteric fracture of femur fixation in biomechanics and anatomical structures. It can be proven that the LISS internal fixator is firmer than the DCS internal fixator by biomechanical comparison.

    Release date:2016-08-31 04:21 Export PDF Favorites Scan
  • Dynamic hip screw combined with anti-rotation screw versus cannulated screw alone for femoral neck fracture in adults: a meta-analysis

    Objective To compare the efficacy and safety of dynamic hip screw (DHS) + anti-rotation screw and cannulated screw alone for femoral neck fracture in adults. Methods PubMed, Web of Science, Cochrane Library, China National Knowledge Infrastructure, SinoMed, Wanfang, and Chongqing VIP database were searched for the literature related to the comparison between DHS + anti-rotation screw and cannulated screw alone for femoral neck fracture in adults from the establishment of databases to 2022. RevMan 5.3 software was used for meta-analysis. Results Finally, 25 clinical studies were included, including 8 randomized controlled trials and 17 observational studies, 5 in English and 20 in Chinese. There were a total of 2099 patients, including 989 in the DHS + anti-rotation screw group and 1110 in the cannulated screw group. The meta-analysis results showed that the incidence of bone nonunion [odds ratio (OR)=0.29, 95% confidence interval (CI) (0.17, 0.48)], incidence of femoral head necrosis [OR=0.48, 95% CI (0.27, 0.88)], failure rate of internal fixation [OR=0.28, 95% CI (0.15, 0.51)] in the DHS + anti-rotation screw group were lower than those in the cannulated screw group (P<0.05). The surgical duration [mean difference (MD)=9.91, 95% CI (6.78, 13.05)], incision length [MD=1.25, 95% CI (0.15, 2.35)], and Harris score [MD=6.77, 95% CI (4.66, 8.88)] in the DHS + anti-rotation screw group were higher than those in the cannulated screw group (P<0.05). There was no statistically significant difference in intraoperative bleeding volume, Visual Analogue Scale score, hospital stay, and fracture healing time between the two groups (P>0.05). The incidence of bone nonunion in the DHS + anti-rotation screw group after Pauwels type Ⅲ fracture [OR=0.16, 95% CI (0.05, 0.50)] was lower than that in the cannulated screw group (P<0.05), and there was no statistically significant difference in the incidence of femoral head necrosis between the two groups (P>0.05). Conclusions For femoral neck fracture in adults, DHS + anti-rotation screw can reduce the incidence of bone nonunion, femoral head necrosis, and internal fixation failure compared with cannulated screw alone, and has a higher Harris score, but the surgical duration and incision are longer. Overall, DHS + anti-rotation screw are better at reducing the incidence of complications than cannulated screws alone.

    Release date:2023-04-24 08:49 Export PDF Favorites Scan
  • AN ANATOMIC STUDY OF LAG SCREW PLACEMENT IN ANTERIOR COLUMN OF ACETABULUM AND DESIGN OF TARGETING DEVICE

    Objective To provide the anatomic basis for thelag screw placement in the anterior column of the acetabulum. Methods Twenty-two pelvis specimens with 44 acetabula of the native adult cadavers were studied. The anthropometric measurement was performed on 44 acetabula to determine the shape of the transverse section of the anterior column of the acetabulum, the optimal entry point for the lag screw on the outer table of the ilium, the direction of the screw, and the distance from the entry point to the obturator groove. Results The transverse section of the anterior column of the acetabulum was almost triangle-shaped. The path for the lag screw placement was 10.5±0.8 mm in diameter. The optimal entry point on the posterolateral ilium for the screw fixation was found toexist 9.2±2.4 mm superior to the line between the anterior superior iliac spine and the greater sciatic notch and 38.5±3.8 mm superior to the greater sciatic notch. The distance from the entry point to the obturator groove was 84.1±6.2 mm. The inclination of the lag screw was 54.2±5.5° at the caudal direction in the sagittal plane and 40.7±3.8° in the horizontal plane. The device for the safe screw placement in the anterior column was designed. Conclusion The above datacan facilitate an insertion of one 6.5 mm lag screw into the anterior acetabular column and minimize the risk of articular violation or cortical penetration, which has a narrow margin of safety. The safe length of the lag screw should be 70 mm.The optimal entry point on the posterolateral ilium for the screw fixationis determined to be 10 mm superior to the line between the anterior superior iliac spine and the greater sciatic notch and 40 mm superior to the greater sciatic notch. The inclination of the lag screw should be 55° at the caudal direction in the sagittal plane and 40° in the horizontal plane. It is safe to place thelag screw in the anterior column with the help of the targeting device.

    Release date:2016-09-01 09:26 Export PDF Favorites Scan
  • Biomechanical research of anterior cruciate ligament fixation by tibial interfacial screw combined with bone tunnel crossing technology

    ObjectiveTo compare the strength difference between the interfacial screw and the interfacial screw combined with bone tunnel crossing technology to fix the tibial end of ligament during anterior cruciate ligament (ACL) reconstruction through the biomechanical test.MethodsTwenty fresh frozen pig tibia were randomly divided into two groups (n=10) to prepare ACL reconstruction models. The graft tendons in the experimental group were fixed with interfacial screw combined with bone tunnel crossing technology, and the graft tendons in the control group were fixed with interfacial screw. The two groups of specimens were fixed in the high-frequency dynamic mechanics test system M-3000, and the length change (displacement), ultimate load, and stiffness of graft tendons were measured through the reciprocating test and load-failure test.ResultsThe results of reciprocating test showed that the displacement of the experimental group was (3.06±0.58) mm, and that of the control group was (2.82±0.46) mm, and there was no significant difference between the two groups (t=0.641, P=0.529). The load-failure test results showed that the stiffness of the experimental group and the control group were (95.39±13.63) and (91.38±14.28) N/mm, respectively, with no significant difference (t=1.021, P=0.321). The ultimate load of the experimental group was (743.15±173.96) N, which was significantly higher than that of the control group (574.70±74.43) N (t=2.648, P=0.016).ConclusionIn ACL reconstruction, the fixation strength of tibial end with interface screw combined with bone tunnel crossing technology is obviously better than that of interface screw alone.

    Release date:2021-10-28 04:29 Export PDF Favorites Scan
  • SURGICAL TREATMENT OF KYPHOSIS WITH UNIVERSAL SPINE SYSTEM

    OBJECTIVE: To introduce a method to treat kyphosis with universal spine system (USS) and to evaluate its clinical effect. METHODS: From January 2000 to September 2002, 31 patients with kyphosis were treated with "one-stage total vertebral wedge-shaped osteotomy" and internal fixation of USS. The average follow-up time was 12 months (6-31 months). We observed the clinical effect with the spinal column Cobb before operation and after operation, and the osteotomy confluence rate. RESULTS: In 31 patients, the average angle (Cobb) was 89 degrees before operation and 74 degrees after operation; the average rate of correction was 83.15% and the average rate of osteotomy confluence was 96.77%. No screw and rod broke and loosened. CONCLUSION: The USS is the reliable internal fixation instrument for the treatment of kyphosis, can increase the osteotomy confluence rate and improve correcting rate.

    Release date:2016-09-01 09:35 Export PDF Favorites Scan
  • APPLICATION OF ATLAS PEDICLE SCREW SYSTEM FIXATION AND FUSION FOR TREATMENT OF UPPER CERVICAL DISEASES

    Objective To explore the feasibilities, methods, outcomes and indications of atlas pedicle screw system fixation and fusion for the treatment of upper cervical diseases. Methods From October 2004 to January 2006, 17 patients with upper cervical diseases were treated with atlas pedicle screw system fixation and fusion. There were 13 males and 4 females, ageing 19 to 52 years. Of 17 cases, there were 14 cases of atlantoaxial dislocation(including 3 cases of congenital odontoid disconnection,4 cases of old odontoid fracture,2 cases of new odontoid fracture(typeⅡC), 3 cases of rupture of the transverse ligament, and 2 cases of atlas fracture; 2 cases of tumor of C2; 1case of giant neurilemoma of C2,3 with instability after the resection oftumors. JOA score before operation was 8.3±3.0. Results The mean operative time and bleeding amount were 2.7 hours (2.1-3.4 hours) and 490 ml (300-750 ml) respectively. No injuries to the vertebral artery and spinal cord were observed. The medial-superior cortex of lateral mass was penetrated by 1 C1 screw approximately 3 mmwithout affecting occipito-atlantal motions. All patients were followed up 3-18 months. The clinical symptoms were improved in some extents and the screws were verified to be in a proper position, no breakage or loosening of screw and rob occurred. All patients achieved a solid bone fusion after 3-6 months. JOA score 3 months after operation was14.6±2.2. JOA improvement rates were 73%-91%(mean 82%). Conclusion The atlas pedicle screw system fixation and fusion is feasible for the treatment of upper cervical diseases and has betteroutcomes, wider indications if conducted properly.

    Release date:2016-09-01 09:22 Export PDF Favorites Scan
  • Comparison of short-term effectiveness of metal screws and absorbable screws in repair of distal tibiofibular syndesmosis

    Objective To compare the short-term effectiveness of repairing distal tibiofibular syndesmosis with metal screws and absorbable screws. Methods A retrospective analysis was performed on the clinical data of 63 patients with ankle fracture combined with injury of the distal tibiofibular syndesmosis admitted between January 2017 and January 2020. Among them, 31 patients were treated with absorbable screw fixation of the distal tibiofibular syndesmosis (research group) and 32 patients were treated with metal screw fixation of the distal tibiofibular syndesmosis (control group). There was no significant difference in gender, age, cause of injury, surgical side, time from injury to operation, fracture type, preoperative visual analogue scale (VAS) score, and American Orthopaedic Foot & Ankle Society (AOFAS) score between the two groups (P>0.05). The operation time and fracture healing time were recorded and compared between the two groups. X-ray film was taken to evaluate the effect of ankle joint reduction and fixation. Olerud-Molander ankle fracture efficacy score (short for OM score), AOFAS score, and VAS score were used to evaluate the effectiveness. Results There was no significant difference in operation time between the two groups (t=−0.683, P=0.497). In the control group, 1 case of delayed healing and 1 case of poor healing occurred in the lateral incision after operation, which healed after dressing change; the rest of the patients had primary healing of the incision. Patients in both groups were followed up 12-24 months, with an average of 13.8 months. In the control group, 1 patient with fracture of pronation and external rotation walked with full weight bearing after removing the metal screw of the distal tibiofibular syndesmosis at 8 weeks after operation, the anatomical plate of the lateral malleolus was broken, and the lateral malleolus was fixed again and recovered after 5 months; 1 patient had mild ankle pain after operation, and the pain disappeared after removing the metal screw of the distal tibiofibular syndesmosis at 8 weeks. No complication such as nerve and blood vessel injury occurred in all patients. There was no significant difference in fracture healing time between the two groups (t=−1.128, P=0.264). The AOFAS and VAS scores significantly improved in both groups at 12 months after operation (P<0.05). There was no significant difference between the two groups in the OM scores, and the difference of AOFAS and VAS scores between before and after operation (P>0.05). Conclusion Using absorbable screws to repair the distal tibiofibular syndesmosis can effectively restore the ankle acupoint structure, prevent ankle instability, and restore good ankle function. There is no significant difference in effectiveness between absorbable screws and metal screws, and there is no need for secondary operation to remove screws.

    Release date:2022-08-29 02:38 Export PDF Favorites Scan
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