目的:探讨后路椎弓根螺钉固定在地震伤胸腰椎骨折中的应用及优点。方法:对19例胸腰椎骨折的地震伤患者行后路椎弓根螺钉内固定术。结果:本组病例的手术时间70～115分钟,平均出血量约280mL,两例病员术中出血超过400mL进行输血,复位椎体前缘高度由术前平均57.5%恢复到术后平均93.6%,后突角由术前平均21°矫正到术后平均3°,术后3～7天转往外地继续治疗,Frankel分级平均提高0.4。结论:后路椎弓根螺钉固定具有省时、节约医疗资源、提高救治效率、减轻患者痛苦的优点,尤其适用于大批伤病员的紧急救治。
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.
Objective To evaluate the biomechanical stability of a newly-designed Y type pedicle screw (YPS) in osteoporotic synthetic bone. Methods The osteoporotic synthetic bone were randomly divided into 3 groups (n=20). A pilot hole, 3.0 mm in diameter and 30.0 mm in deep, was prepared in these bones with the same method. The YPS, expansive pedicle screw (EPS), and bone cement-injectable cannulated pedicle screw (CICPS) were inserted into these synthetic bone through the pilot hole prepared. X-ray film examination was performed after 12 hours; the biomechanical stability of YPS, EPS, and CICPS groups was tested by the universal testing machine (E10000). The test items included the maximum axial pullout force, the maximum running torque, and the maximum periodical anti-bending. Results X-ray examination showed that in YPS group, the main screw and the core pin were wrapped around the polyurethane material, the core pin was formed from the lower 1/3 of the main screw and formed an angle of 15° with the main screw, and the lowest point of the inserted middle core pin was positioned at the same level with the main screw; in EPS group, the tip of EPS expanded markedly and formed a claw-like structure; in CICPS group, the bone cement was mainly distributed in the front of the screw and was dispersed in the trabecular bone to form a stable screw-bone cement-trabecular complex. The maximum axial pullout force of YPS, EPS, and CICPS groups was (98.43±8.26), (77.41±11.41), and (186.43±23.23) N, respectively; the maximum running torque was (1.42±0.33), (0.96±0.37), and (2.27±0.39) N/m, respectively; and the maximum periodical anti-bending was (67.49±3.02), (66.03±2.88), and (143.48±4.73) N, respectively. The above indexes in CICPS group were significantly higher than those in YPS group and EPS group (P<0.05); the maximum axial pullout force and the maximum running torque in YPS group were significantly higher than those in EPS group (P<0.05), but there was no significant difference in the maximum periodical anti-bending between YPS group and EPS group (P>0.05). Conclusion Compared with EPS, YPS can effectively enhance the maximum axial pullout force and maximum rotation force in the module, which provides a new idea for the design of screws and the choice of different fixation methods under the condition of osteoporosis.
Objective To develop a high-accuracy, better-safety and low-cost cervical pedicle locator system for guiding cervical pedicle screw placement. Methods Cervical pedicle screw locator system was made of stainless steel. Ten cervical specimens from voluntary donation were divided into two groups according to compatibil ity design: control group inwhich 60 screws were planted into C2-7 by free hand; and experimental group in which 60 screws were planted into C2-7 under the guidance of three-dimensional locator system. The condition of screw insertion was observed and the accuracy was evaluated by the integrity of pedicle walls. Results In the control group, 32 screws (53.33%) were placed inside the pedicles and 28 (46.67%) were outside; 9 screws (15.00%) led to nerve root injury, 5 screws (8.33%) caused vertebral artery injury and no spinal cord injury occurred; and the qual ification ratio of screw insertion was 76.67% (excellent 32, fair 14, poor 14). While in the experimental group, 54 screws (90.00%) were placed inside the pedicles and 6 (10.00%) were outside; 1 screw (1.67%) caused vertebral artery injury and no nerve root injury and spinal cord injury occurred; and the qual ification ratio of screw insertion was 98.33% (excellent 54, fair 5, poor 1). There was significant difference between the two groups (P lt; 0.05). Conclusion Cervical pedicle screw locator system has the advantages of easy manipulation, high accuracy of screw placement and low cost. With further study, it can be appl ied to the cl inical.
To investigate the shortsegment pedicle screw in treating degenerative L4 spondylolisthesis and the relationship of the preliminarily bending degree of the titanium rod with the lumbar lordosisangle, the slipping angle and the slipping percentage and to evaluate the clinical coincidence and curative effects of the preliminarilybent rod. MethodsFrom September 2005 to March 2007, 31 female patients (age, 40-70 years; average, 58.3 years) were admitted for surgical treatment of their L4 degenerative spondylolisthesis (MeyerdingⅠ°, Ⅱ°)． Their lumbar lordosis angle （x1）, slipping angle (x2), and slipping percentage (x3) were measured in the L4,5 segment before operation. During the operation, the titanium rod bent beforehand according to the corresponding standards was inserted. The angle of the bent rod (Y) was measured, and then the multiple linear regression equation was established. The regression equation was applied to the surgical treatment of the 30 patients.Results According to the criteria in the JOA scoring system, the 31 patients had scores of 8.300± 1.080 and 26.916±1.859 before operation and after operation, respectively. There was a significant difference between before operation and after operation（Plt;0.05）. The established multiple linear regression equation was as follows:Y=0.1390-0.327logx1+0.463x2+0.288x32．The operating time was 51.290±3.408 min in the 30 patients who underwent an insertion of the preliminarilybent rod during the operation; however, the operating time was 102.360±5.004 min in the 31 patients who underwent an insertion of the bent rod that was made based on experience during the previous operations. There was a significant difference in the operating time between the two kinds of the rods （Plt;0.05）. Estimated according to 90%, 95% and 99% of the areas under the normalcurve, the clinical coincidence rates in the preliminarily bending degrees of the titanium rod in the 30 patients were 80.00％，90.00％ and 96.67％, respectively.Conclusion The titanium rod that has been bent into a certain angle before operation according to the established criteria can definitely diminish its strain during operation and efficiently shorten the operating time．Thiskind of the titanium rod has a good coincidence in clinical application and can be effectively used in clinical practice.It is worth reference during the clinical operation.
OBJECTIVE: To observe the early clinical results with degenerative lumbar instability treated with transpedical screw fixation and intertransverse process autogenous bone grafting. METHODS: From September 2000 to February 2002, 19 patients (5 males and 14 females) of degenerative lumbar spine instability were treated with decompression for spinal canal stenosis, transpedical screw fixation and intertransverse process autogenous bone grafting. The locations of degenerative lumbar spine instability were between L4 and L5 in 10 patients, between L3, L4 and L5 in 4 cases, between L3 and L4 in 3 cases, between L5 and S1 in 2 cases. The results were evaluated after operation. The preoperative clinical symptoms disappeared completely as excellent results, relieved obviously as good results, improved as fair results and unrelieved or worsened as poor results. RESULTS: Seventeen patients were followed up for 4-18 months with an average of 8.1 months. The results of the treatment were excellent in 12 patients, good in 4 patients and fair in 1 patient. The excellent and good rate was 94.1%. Intertransverse process arthrodesis was obtained after 6 months of operation in all cases. No loosened and broken instruments occurred. CONCLUSION: The advantages of degenerative lumbar spine instability treated with transpedical screw fixation and intertransverse are reliable fixation, high successful rate of fusion and less influence on spinal canal. The above results show satisfactory clinical outcome.
Objective To explore the clinical effect of PSIS-A robot-assisted percutaneous screw in the treatment of thoracolumbar fracture. Methods Patients with thoracolumbar fracture who were hospitalized in Mianyang Orthopedic Hospital between August 2022 and January 2024 and required percutaneous pedicle screw f ixation were selected. Patients were divided into robot group and free hand group by random number table. Operative time, intraoperative bleeding, intraoperative radiation dose and time, implant accuracy rate, small joint invasion rate, Visual Analogue Scale score for pain and other indexes were compared between the two groups. Results A total of 60 patients were included. Among them, there were 28 cases in the robot group and 32 cases in the free hand group. On the third day after surgery, the Visual Analogue Scale score of the robot group was better than that of the free hand group (P=0.003). Except for intraoperative bleeding and radiation frequency (P>0.05), the surgical time, average nail implantation time, and intraoperative radiation dose in the robot group were all lower than those in the free hand group (P<0.05). The accuracy and excellence rate of nail planting in the robot group were higher than those in the free hand group (94.6% vs. 84.9%; χ2=7.806, P=0.005). There was no statistically significant difference in the acceptable accuracy rate (96.4% vs. 91.1%; χ2=3.240, P=0.072) and the incidence of screw facet joint invasion (7.2% vs.14.1%; χ2=3.608, P=0.058) between the two groups. Conclusion The application of PSIS-A type robot assisted percutaneous minimally invasive pedicle screw fixation in the treatment of thoracolumbar fr actures is promising.
ObjectiveTo explore the effectiveness percutaneous monoaxial screw combined with polyaxial pedical screw for treating thoracolumbar fracture by comparing with simple polyaxial pedicle screw fixation. MethodsBetween January 2012 and June 2014, 56 cases of thoracolumbar fractures were treated by percutaneous pedicle screw fixation, the clinical data were retrospectively analyzed. Of 56 cases, 30 were treated with percutaneous monoaxial screw combined with percutaneous polyaxial pedical screw fixation (group A), 26 patients with only percutaneous polyaxial pedicle screw fixation (group B). There was no significant difference in gender, age, body mass index, injury causes, time from injury to admission, involved segments, fracture type, and preoperative American Spinal Injury Association (ASIA) stage, visual analogue scale (VAS), the anterior height of the injured vertebrae, Cobb angle, and sagittal index between 2 groups (P>0.05). The operation time, intraoperative blood loss, and complications were recorded and compared between the 2 groups. The VAS score was used to evaluate the improvement of the pain. The sagittal kyphosis Cobb angle, the anterior height of the injured vertebrae, sagittal index, and the average correction (difference between 3 days after oeration and preoperation) and loss degrees (difference between last follow-up and 3 days after operation) were measured on the X-ray films at preoperation, 3 days after operation, and last follow-up. ResultsIncision healing at stage I was obtained, no related complications occurred. The operation time and intraoperative blood loss showed no significant difference between 2 groups (P>0.05). The patients were followed up 20-42 months (mean, 32 months) in group A and 21-44 months (mean, 30 months) in group B. VAS score of group A was significantly lower than that of group B at 3 days after operation (t=-2.277, P=0.027), but no significant difference was found at last follow-up (t=-0.289, P=0.774). X-ray examination showed good position of internal fixation, with no broken nails or exit of nail. There were significant differences in the anterior height of the injured vertebrae, Cobb angle, and sagittal index between at preoperation and at 3 days and last follow-up, and between at 3 days and last follow-up in 2 groups (P<0.05). The anterior height of the injured vertebrae, Cobb angle, and sagittal index of group A were significantly better than those of group B at 3 days and last follow-up (P<0.05), and correction degree were significantly higher than those of group B (P<0.05), but loss degree was not significant between 2 groups (P>0.05). ConclusionPercutaneous monoaxial screw combined with polyaxial pedicle screw fixation is better than simply polyaxial pedicle screw in effects of treating thoracolumbar fracture under the premise of strictly holding indications.
ObjectiveTo investigate the accuracy of progressive three-dimensional navigation template system (abbreviated as progressive template) to assist atlas-axial pedicle screw placement. MethodsThe clinical data of 33 patients with atlas-axial posterior internal fixation surgery between May 2015 and May 2017 were retrospectively analyzed. According to the different methods of auxiliary screw placement, the patients were divided into trial group (19 cases, screw placement assisted by progressive template) and control group (14 cases, screw placement assisted by single navigation template system, abbreviated as initial navigation template). There was no significant difference in gender, age, cause of injury, damage segments, damage types, and preoperative Frankel classification between the two groups (P>0.05). The operation time and intraoperative blood loss of the two groups were compared. The safety of screw placement was evaluated on postoperative CT by using the method from Kawaguchi et al, the deviation of screw insertion point were calculated, the angular deviation of the nailing on coordinate systems XOZ, XOY, YOZ were calculated according to Peng’s method. ResultsAll patients completed the operation successfully; the operation time and intraoperative blood loss in the trial group were significantly less than those in the control group (t=–2.360, P=0.022; t=–3.006, P=0.004). All patients were followed up 12–40 months (mean, 25.3 months). There was no significant vascular injury or nerve injury aggravation. Postoperative immediate X-ray film and CT showed the dislocation was corrected. Postoperative immediate CT showed that all 76 screws were of grade 0 in the trial group, and the safety of screw placement was 100%; 51 screws were of grade 0, 3 of gradeⅠ, and 2 of gradeⅡ in the control group, and the safety of screw placement was 91.1%; there was significant difference in safety of screw placement between the two groups (χ2=7.050, P=0.030). The screw insertion point deviation and angular deviation of the nailing on XOY and YOZ planes in the trial group were significantly less than those in the control group (P<0.05). There was no significant difference in angular deviation of the nailing on XOZ between the two groups (t=1.060, P=0.290). ConclusionCompared with the initial navigation template, the progressive navigation template assisting atlas-axial pedicle screw placement to treat atlas-axial fracture with dislocation, can reduce operation time and intraoperative blood loss, improve the safety of screw placement, and match the preoperative design more accurately.
Objective To investigate the classification of atlas pedicles and the methods of the pedicle screw fixation. Methods To study the classification of atlas pedicles, 48 dry adult atlas specimens were measured. By atlas 3D-CT reconstruction, two transverse sections were establ ished by going through the one third of the lateral atlas pedicle and 2 mmbelow the vertebral artery sulcus. By setting 3.50 mm and 1.75 mm as the standardized diameter and radius for the screwand according to the thickness of bone substance of vertebral artery sulcus that went through the one third of the lateralatlas pedicle, the anatomical morphology of atlas pedicles were classified into three types: general type with 40 specimens (83%), l ight variation type with 6 specimens (13%), and severe variation type with 2 specimens (4%). The entry pathway was confirmed by the intersection l ine of the two transverse sections that went through the lateral one third of the atlas pedicle and 2 mm below the vertebral artery sulcus. The project-point of the entry pathway on the atlas posterior arch was considered to be the entry point. Forty-eight dry atlas specimens were used to measure the following relevant anatomic data with an electronic cal iper: the distance between the entry point and the posterior margin of the lateral mass (L1), the height of atlas pedicle at the entry point (L2), the vertical distance between the entry point and the inferior articular facet of the lateral mass (L3), the mass height at the entry point (L4), the mass width at the entry point (L5), the width of the atlas pedicle at the entry point (L6), the thickness of the pedicle under the vertebral artery sulcus at the entry pathway (H1). To research the method of the pedicle screw fixation, 12 fresh-frozen adult atlas specimens were adopted to simulate the fixation of the pedicle screw. The thickness of the bone substance of vertebral artery sulcus on both the left and the right sides of the pathway was grinded into 3 types: 1.5 mm and 2.5 mm, 1.5 mm and 4.0 mm, 2.5 mm and 4.0 mm, and each type had four specimens. The entry pathway was confirmed by the intersection l ine of two transverse sections that went through the lateral one third of atlas pedicle and 2 mm below the vertebral artery sulcus. Results On the left side, L1 was (5.79 ± 1.24) mm, L2 (4.55 ± 1.29) mm, L3 (5.12 ± 1.06) mm, L4 (12.43 ± 1.01) mm, L5 (12.66 ± 1.37) mm, L6 (7.86 ± 0.77) mm, and H1 (4.11 ± 1.25) mm. On the right side, L1 was (5.81 ± 1.26) mm, L2 (4.49 ± 1.22) mm, L3 (5.15 ± 1.05) mm, L4 (12.49 ± 0.98) mm, L5 (12.65 ± 1.38) mm, L6 (7.84 ± 0.78) mm, and H1 (4.13 ± 1.29) mm. There was no significant difference between the two sides (P gt; 0.05). After simulation of inserting screws, no screw in the specimens was found to break the bone substance in the sulcus of vertebral artery. Conclusion For the pedicle screw fixation of those patients whose atlas posterior arches are not high enough, we might partly drill through or beyond the atlas posterior arch. The entry point should be ascertained by preoperative 3D-CT reconstruction and intra-operative exploration.