Objective To evaluate the accuracy of pedicle guide device for the placement of the pedicle screws. Methods Pedicle guide device was designed and made for the anatomical trait of pedicle. The 3-Danatomical data of the thoracic pedicles were measured by multislice spiral CT in two embalmed human cadaveric thoracic pedicles spine(T1 -T10). Depending on transverse section angle(TSA) and sagittal section angle(SSA) of pedicle axis, the degree of horizontal dial and sagittal dial were adjusted in the guide device. The screws wereinserted bilaterally in the thoracic pedicles by using the device. After pulling the screws out, the pathways were filled with contrast media. The TSA and SSA of developed pathways were measured. Results Analysis of the difference between pedicle axis and developed pathway was of no statistical significance(P＞0.05). Conclusion The guide device could be easilyoperated and guarantee high accuracy of the pathways of screws and the incidence of pedicle penetration could be significantly reduced.
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.
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.
OBJECTIVE: To review the anatomic character of lower cervical pedicle, the placement and the biomechanical stability of the cervical pedicle screw fixation, the clinical application and the complication caused by fixation. METHODS: The literature concerned the cervical pedicle screw fixation in recent years were extensively reviewed. RESULTS: The cervical pedicle screw fixation can be widely used in the lower cervical spine instability according to the anatomic character of lower cervical pedicle, and the good biomechanical stability of the cervical pedicle screw fixation, and the complication can be controlled. CONCLUSION: The cervical pedicle screw fixation is an effective internal fixation for the lower cervical spine instability.
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.
Objective To compare the curative effect of posterior lumbar interbody fusion with autologous il iac crest to that of interbody fusion cage for adult instabil ity of lower lumbar. Methods From February 2003 to October 2006,60 inpatients with lower lumbar instabil ity were treated. Patients were randomized into 2 groups: bone-graft group (n=28) was treated with posterior lumbar interbody fusion with two autologous il iac crests, while cage group (n=32) was treated with posterior lumbar interbody fusion with two quadrate cages. In the bone-graft group, 17 males and 11 females aged (52.78 ± 10.50) years with 3-16 months of disease course, there were 12 cases of degenerative instabil ity, 14 isthmus sl it ol isthe and 2 iatrogenic instabil ity, including 1 case of L3,4, 17 cases of L4,5 and 10 cases of L5, S1. Relative disc space height was (23.24 ± 6.62) mm, disc space activity was (10.50 ± 5.07)º, sagittal saw sl ippage distance was (4.50 ± 1.15) mm and the JOA score was 18.56 ± 2.68. In the cage group, 19 males and 13 females aged (51.75 ± 10.44) years with 3.5-14.0 months of disease course, there were 16 cases of degenerative instabil ity, 14 isthmus sl it ol isthe and 2 iatrogenic instabil ity, including 16 cases of L4,5 and 16 cases of L5, S1. Relative disc space height was (24.34 ± 7.22) mm, disc space activity was (11.12 ± 5.67)º, sagittal saw sl ippage distance was (4.38 ± 0.75) mm and the JOA score was 19.00 ± 4.12. There was no significant difference between the two groups in termsof age, gender, JOA score, disc space activity and relative disc space height preoperatively (P gt; 0.05). Results All patients received the follow-up at the 1st, 3rd, 6th and 12th month postoperatively. There was no significant difference in operation time and hemorrhage amount between the two groups (P gt; 0.05), but significant difference in the cost of operation (P lt; 0.01). Two cases in the bone-graft group suffered donor site pain and received no treatment. Three cases in the bone-graft group and 2 cases in the cage group had symptom of nerve injury 1-2 days after surgery, which were cured after expectant treatment. There were no pseudoarticulation formation, intervertebral space infection and cage aversion in both groups. Significant difference of relative disc space height was found in each group pre- and post- operatively (P lt; 0.01) and significant differences were evident between the two groups at any of the time points (P lt; 0.01). One month after operation, there was significant difference between the two groups (P lt; 0.05). There was also significant difference at the 3rd, 6th and 12th month after operation (P lt; 0.01). No sign offusion was found in each group at the 1st and 3rd month after operation. In bone-graft group, there were 7 vertebral fusion cases 6 months after operation and 23 vertebral fusion cases 12 months after operation. In cage group, there were 8 vertebral fusion cases 6 months after operation and 29 vertebral fusion cases 12 months after operation. There was no significant difference in the rate of fusion at 6 and 12 months follow-up between the two groups (P gt; 0.05). Significant difference of JOA scores was found in each group pre- and post- operatively (P lt; 0.05). And no significant difference in JOA scores at 1, 3, 6, and 12 months follow-up was evident between the two groups (P gt; 0.05). Conclusion There is no significant difference between the two groups in the fusion time, the fusion rate and the cl inical symptoms alleviation, indicating autologous il iac crest is appl icable to interbody fusion for the treatment of adult instabil ity of lower lumbar and good therapeutic effect can be achieved with no immunoreaction and lower cost.
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.
【Abstract】 Objective To study the effectiveness of computer assisted pedicle screw insertion in osteoporotic spinalposterior fixation. Methods Between December 2009 and March 2011, 51 patients underwent pedicle screw fixation using the computer assisted navigation (navigation group), while 41 patients underwent the conventional technique (traditional group). All patients had osteoporosis under the dual-energy X-rays absorptiometry. There was no significant difference in age, gender, bone mineral density, involved segment, preoperative complications, and other general status between 2 groups (P gt; 0.05). The amount of blood loss, the operation time, the rate of the pedicle screw re-insertion, and the postoperative complication were observed. The state of the pedicle screw location was assessed by CT postoperatively with the Richter’s classification and the fusion state of the bone graft was observed using three-dimensional (3-D) CT scans during follow-up. Results A total of 250 screws were inserted in navigation group, and 239 were inserted successfully at first time while the other 11 screws (4.4%) were re-inserted. A total of 213 screws were inserted in traditional group, and 190 were successful at first time while 23 screws (10.8%) were re-inserted. There was significant difference in the rate of screws re-insertion between 2 groups (χ2=6.919, P=0.009). Both the amount of blood loss and the operation time in navigation group were significantly less than those in traditional group (P lt; 0.05). According to Richter’s classification for screw location, the results were excellent in 240 screws, good in 10 screws innavigation group; the results were excellent in 191 screws, good in 21 screws, and poor in 1 screw in traditional group. Significant difference was noticed in the screw position between 2 groups (χ2=7.566, P=0.023). The patients were followed up (7.8 ± 1.5) months in navigation group and (8.7 ± 1.5) months in traditional group. No loosening, extraction, and breakage of the pedicle screw occurred in navigation group, and all these patients had successful fusion within 6 months postoperatively. While in traditional group, successful fusion was shown in the other patients by 3-D CT, except the absorption of bone graft was found in only 1 patient at 6 months after operation. And then, after braking by adequate brace and enhancing the anti-osteoporotic therapy, the bone graft fused at 9 months postoperatively. Conclusion The computer assisted navigating pedicle screw insertion could effective reduce the deviation or re-insertion of the screws, insuring the maximum stabil ity of each screw, mean while it can reduce the exposure time and blood loss, avoiding complication. The computer assisted navigation would be a useful technique which made the pedicle screw fixation more safe and stable in patients with osteoporosis.
ObjectiveTo determine the entry point and screw implant technique in posterior pedicle screw fixation by anatomical measurement of adult dry samples of the axis so as to provide a accurate anatomic foundation for clinical application. MethodsA total of 60 dry adult axis specimens were selected for pedicle screws fixation. The entry point was 1-2 mm lateral to the crossing point of two lines: a vertical line through the midpoint of distance from the junction of pedicle medial and lateral border to lateral mass, and a horizontal line through the junction between the lateral border of inferior articular process and the posterior branch of transverse process. The pedicle screw was inserted at the entry point. The measurement of the anatomic parameters included the height and width of pedicle, the maximum length of the screw path, the minimum distance from screw path to spinal canal and transverse foramen, and the angle of pedicle screw. The data above were provided to determine the surgical feasibility and screw safety. ResultsThe width of upper, middle, and lower parts of the pedicle was (7.35±0.89), (5.50±1.48), and (3.97±1.01) mm respectively. The pedicle height was (9.94±1.16) mm and maximum length of the screw path was (25.91±1.15) mm. The angle between pedicle screw and coronal plane was (26.95±1.88)° and the angle between pedicle screw and transverse plane was (22.81±1.61)°. The minimum distance from screw path to spinal canal and transverse foramen was (2.72±0.83) mm and (1.98±0.26) mm respectively. ConclusionAccording to the anatomic research, a safe entry point for C2 pedicle screw fixation is determined according to the midpoint of distance from the junction of pedicle medial and lateral border to lateral mass, as well as the junction between the lateral border of inferior articular process and the posterior branch of transverse process, which is confirmed to be effectively and safely performed using the entry point and screw angle of the present study.
ObjectiveTo investigate the short-term effectiveness of balloon vertebroplasty combined with short-segment pedicle screw instrumentation for the treatment of thoracolumbar burst fractures. MethodsBetween June 2011 and December 2013, 22 patients with thoracolumbar burst fractures were included. There were 14 males and 8 females, aged 20-60 years (mean, 42.5 years). The fracture segments included T11 in 1 case, T12 in 4 cases, L1 in 10 cases, L2 in 6 cases, and L3 in 1 case. According to AO classification system, there were 13 cases of type A and 9 cases of type B. Spinal cord injury was classified as grade C in 2 cases, grade D in 3 cases, and grade E in 17 cases according to Frankel scale. The time from injury to operation was 3-10 days (mean, 5.5 days). All patients underwent posterior reduction and fixation via the injured vertebra, transpedicular balloon reduction of the endplate and calcium sulfate cement (CSC) injection. The ratio of anterior vertebral height, the ratio of central vertebral height, the sagittal Cobb angle, the restoration of nervous function, and internal fixation failure were analyzed. ResultsPrimary healing of incision was obtained in the others except 2 cases of poor healing, which was cured after dressing change or debridement. All the patients were followed up 9-40 months (mean, 15 months). CSC leakage occurred in 2 cases. Absorption of CSC was observed at 8 weeks after operation with complete absorption time of 12-16 weeks (mean, 13.2 weeks). The mean fracture healing time was 18.5 weeks (range, 16-20 weeks). The ratio of anterior vertebral height, ratio of central vertebral height, and sagittal Cobb angle were significantly improved at 1 week and 3 months after operation and last follow-up when compared with preoperative values (P<0.01), but no significant difference was found among 3 time points after operation (P>0.01). There was no internal fixation failure or Cobb angle loss more than 10°. Frankel scale was improved with no deterioration of neurologic function injury. ConclusionBalloon vertebroplasty combined with short-segment pedicle screw instrumentation is simple and safe for the treatment of thoracolumbar burst fractures, and it can improve the quality of reduction, restore vertebral mechanical performance effectively, and prevent the loss of correction and internal fixation failure.