Objective To summarize the methods andskills of anterior cervical locking plate systems in clinical application and to analyze the causes of some complications as well as give some preventive or remedial countermeasures. Methods From 1998 to 2002, 159 patients with cervical spondylotic myelopathy,fracturedislocation,tumor or tuberculosis of the cervical spine were treated with anterior locking plate systems. The complications were reviewed and analyzed. Results Ten kinds of complications related to anterior locking plate systems occurred in 21 patients. Most of the complications were caused by improperly-selecting implants, experience and technique deficiency. Conclusio The important preventive or remedial countermeasures are correctly-selecting patients, meticulous preoperative preparation, properly-selecting implants, standard and skillful manipulation and rational postoperative protection.
Objective To investigate the cl inical appl icabil ity and value of internal fixator for the reconstruction of lumbar isthmus in the treatment of lumbar vertebral spondylolysis and to lay a fundation for its cl inical appl ication. Methods Sixteen healthy goats weighing 22.65-31.22 kg were selected to establ ish the models of vertebral spondylolysis at L5, which thereafter were randomized into two groups (n=8): bone graft group in which 0.8-1.1 g fresh autogenous bone was transplanted into the isthmus spondylolysis area, and internal fixation with bone graft group in which internal fixator was installed before transplanting 0.8-1.1 g fresh autogenous bone into the isthmus spondylolysis area. All animals were killed 8 weeks after operation to receive imaging, topographic anatomy and histology detection. Meanwhile, biomechanics test was performed by using 5 donated vertebral body specimens (4 males and 1 female aged 35-51 years old). The left isthmus of L5 vertebra was transected to serve as lumbar vertebral spondylolysis model. A mini-displacement sensor was put at the transected ends of the isthmus. Then loading was conducted with a constant velocity of 2 mm/min by electronic omnipotent tester simulating the direction of fixation force of the internal fixator, and the deformation value of the transected ends was collected by a dynamic data collector and analyzer. The loading wascontinued until the vertebra specimens were damaged. The deformation of displacement sensor and the closure of transected ends of the lumbar isthmus were observed. Results All the goats behaved normally shortly after operation, and no nerve injury induced by operation and no wound infection occurred. Bilaterally obl ique X-ray films of lumbar vertebra and topographic anatomy 8 weeks after operation showed the fusion rate of the internal fixation and bone graft group and the bone graft group was 100% and 62.5%, respectively, indicating there was a significant difference (P lt; 0.05). Histology observation showed 3 goats in the bone graft group presented empty bone trabecula, empty bone lacuna and the disappearance of osteocytes at the transected ends of lumbar isthmus; while in the internal fixation and bone graft group, the bone trabecula grew into cancellous structures with hematopoietic and fatty bone marrow tissue inside, and parts of the bone trabecula had various degrees of mosaic-l ike pattern. During the upload, the biomechanics test and data processing results showed when the external load was 40 N, the deformation of displacement sensor was identified and the gap between the transected ends of lumbar isthmus started to close; then with the increase of external load, the displacement sensor tended to ascend in a l inearity manner; while when the external load was 212 N, the displacement sensor had no further deformation, the gap between the transected ends of lumbar isthmus wascompletely closed, and the pressor effect appeared. Conclusion The internal fixator for the reconstruction of lumbar isthmus has mechanical effects of stabil izing and elevating pressure with a high fusion rate.
Objective To investigate the cl inical outcomes of lumbar spondylol isthesis associated with lumbar spinal stenosis through decompressive laminectomy, spondylol ithesis reduction system (SRS) internal fixation, single posteriolateralVigor Spacer threaded fusion cages and intertransverse process arthrodesis bone grafting. Methods From June 2002 to June 2006, 58 cases of lumbar spondylol isthesis were treated with decompressive laminectomy, fixed by SRS instrumentation, posterior installed with interbody Vigor Spacer Cage and bone grafted between intertransverse process arthrodesis. There were 47 males and 11 females, aged 32-66 years old (45.8 on average). The course of disease was 3 months to 7 years, with an medium course of 25 months. Accoding to the Meyerding standard, 38 cases were classified as degree I and 20 as degree II. Spondylol isthesis between L4 and L5 covered 21 cases and between L5 and S1 covered 37 cases. There were 44 cases of lumbar spondylol isthesis and 14 of degenerative lumbar spondylol isthesis. The intervertebral height was 1.5-10.5 mm with the average of 5.1 mm. Results All patients’ incisions obtained heal ing by first intension after operation. The operation time was 50-90 minutes with an average of 65 minutes. The blood loss was 200-500 mL with an average of 250 mL. The patients were followed up for 10-38 months with an average of 23.6 months. According to the Macrab criteria, 54 cases were excellent, 3 good, 1 fair and the choiceness rate was 98.3%. According to the Meyerding classification, 38 cases of degree I and 19 out of 20 cases of degree II obtained complete reduction, and the rate of complete reduction was 98.3%. There were 57 (98.3%) cases which fused well 3-6 months after operation. The intervertebral height resumed to 9.6-12.5 mm with an average of 11.6 mm, and no intervertebral height loss was found. Conclusion The treatment of lumbar spondylol isthesis with decompressive laminectomy, SRS internal fixation, single posteriorolateral Vigor Spacer threaded fusion cage and bone grafting has excellent cl inical results and stable reduction.
ObjectiveTo investigate the accuracy of the two-dimension computer-aided surgery navigation system in the lumbar pedicle screw fixation on recombinant CT section after operation. MethodsBetween February 2011 and April 2013, 218 patients undergoing lumbar spinal pedicle screw fixation were divided into 2 groups:two-dimension computer-aided surgery navigation system was used in 95 cases (the navigation group) and X-ray fluoroscopy assistant technology in 123 cases (the fluoroscopy assistant group). There was no significant difference in age, gender, and type of disease between 2 groups (P>0.05). The mean operating time, blood loss volume, and fluoroscopy times, and the one-time success rate of pedicle screw implant were observed. The sagittal screw angle (SSA), the relationship between the pedicle cortex and screw, the accuracy rate of pedicle screw, and the sagittal angle on both sides (SBA) were observed. ResultsA total of 504 screws were inserted in navigation group, 432 (85.7%) were inserted successfully at first time and 472 (85.7%) were inserted successfully at end time. A total of 656 screws were inserted in fluoroscopy assistant group, 474 (72.3%) were successfully inserted at first time, and 563 (85.8%) were inserted successfully at end time. There were significant differences in the one-time success rate and final success rate of pedicle screw implant between 2 groups (χ2=30.19, P=0.00; χ2=18.16, P=0.00). There was no significant difference in the mean operating time and the blood loss volume of pedicle screw implant between 2 groups (t=0.88, P=0.38; t=1.47, P=0.14); but the fluoroscopy times of pedicle screw implant in navigation group 0.7±0.3 were significantly less than that in fluoroscopy assistant group 1.5±1.0 (t=-8.09, P=0.00). The SSA and SBA in navigation group[(3.7±0.9)° and (1.7±0.8)°] were significantly less than those in fluoroscopy assistant group[(6.0±1.7)° and (3.5±1.6)°] (t=-26.92, P=0.00; t=-22.49, P=0.00). ConclusionThe sagittal screw angle and accuracy of pedicle screw implant can be significantly improved using the two-dimension computer-aided surgery navigation system in lumbar posterior fixation.
ObjectiveTo summarize the evolving concept in treatment of intertrochanteric fractures and the development of internal fixation devices. MethodsRelated literature concerning the implant devices to treat intertrochanteric fractures was reviewed and analyzed in terms of the biomechanical characteristics, clinical application, and complications. ResultsThe treatment of intertrochanteric fractures has undergone an evolving concept from conservative treatment to surgical treatment. Surgery strategies include extramedullary fixation and intramedullary fixation. Intramedullary fixation has gradually become the main treatment of intertrochanteric fractures due to its minimally invasive and biomechanical advantages. However, the current intramedullary fixation system still can not reconstruct the medial cortical support of the proximal femur, which leads to some failures in the treatment of unstable fractures. ConclusionThe development of internal fixation of intertrochanteric fractures is based on the deep understanding and biomechanical theory of intertrochanteric fractures in clinical practice. In the future, the updated design of internal fixation devices will depend on the treatment principle of reconstruction of medial support and secondary stabilization of intertrochanteric fractures, and finally the purpose of improving success rate and reducing postoperative complications of intertrochanteric fracture will achieved.
【Abstract】 Objective To determine the three-dimensional stabil ity of atlantoaxial reconstruction withanterior approach screw fixation through C2 vertebral body to C1 lateral mass and Gall ie’s technique (ASMG) for C1,2instabil ity. Methods Twenty-five human cadaveric specimens (C0-3 ) were divided randomly into 5 groups (n=5). Thethree-dimensional ranges of motion C1 relative to C2 were measured under the five different conditions：the intact state group (group A), type II odontoid fracture group (group B), posterior C1,2 transarticular screw fixation group (group C), ASM group (group D) and ASMG group (group E). The three-dimensional ranges of motions C1 relative to C2 by loading ± 1.5 Nm were measured under the six conditions of flexion/extension, left/right lateral bending, and left/right axial rotation. The obtained data was statistically analyzed. Results In each group, the three-dimensional ranges of motion C1 relative to C2 under the six conditions of flexion/extension, left/right lateral bending, and left/right axial rotation were as follows: in group A (8.10 ± 1.08), (8.49 ± 0.82), (4.79 ± 0.47), (4.93 ± 0.34), (28.20 ± 0.64), (29.30 ± 0.84)°; in group B (13.60 ± 1.25), (13.80 ± 0.77), (9.64 ± 0.53), (9.23 ± 0.41), (34.90 ± 0.93), (34.90 ± 1.30)°; in group C (1.62 ± 0.10), (1.90 ± 0.34), (1.25 ± 0.13), (1.37 ± 0.28), (0.97 ± 0.14), (1.01 ± 0.17)°; in group D (2.03 ± 0.26), (2.34 ± 0.49), (1.54 ± 0.22), (1.53 ± 0.30), (0.80 ± 0.35), (0.76 ± 0.30)°; in group E (0.35 ± 0.12), (0.56 ± 0.34), (0.44 ± 0.15), (0.55 ± 0.16), (0.43 ± 0.07), (0.29 ± 0.06)°. Under the six conditions, there were generally significant differences between group A and other four groups, and between group B and groups C, D and E (P lt; 0.001), and between group E and groups C, D in flexion/ extension and left/right lateral bending (P lt; 0.05). There was no significant difference between group E and groups C, D in left/right axial rotation (P gt; 0.05). Conclusion In vivo biomechanical studies show that ASMG operation has unique superiority in the reconstruction of the atlantoaxial stabil ity, especially in controll ing stabil ity of flexion/extension and left/right lateral bending, and thus it ensures successful fusion of the implanted bone. It is arel iable surgical choice for the treatment of the obsolete instabil ity or dislocation of C1, 2 joint.