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.
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.
【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.
To compare the effectiveness of the operations in treatment of thoracolumber spine fracture and dislocation with spinal cord injury in different periods. Methods Between June 2003 and June 2008, 80 cases of thoracolumber spine fracture and dislocation with spinal cord injury were treated. There were 52 males and 28 females with an average age of 37.6 years (range, 28-49 years). According to different operative time, they were divided into 2 groups by randomized controlled study: group A (n=39, operation was performed within 24 hours) and group B (n=41, operation was performed at 3-7 days). In group A, there were 23 cases of degree I-II (group A1), 16 cases of degree III-V (group A2) according to Meyerding standard, including 17 cases of grade A, 7 cases of grade B, 9 cases of grade C, and 6 cases of grade D according to Frankel scoring system. In group B, there were 21 cases of degree I-II (group B1) and 20 cases of degree III-V (group B2), including 20 cases of grade A, 7 cases of grade B, 11 cases of grade C, and 3 cases of grade D. All cases were treated with posterior spinal cord decompression and reduction, with internal fixation by pedicle screw-rod system and transforamen lumbar interbody fusion. Results The blood loss was (407.4 ± 24.3) mL in group A1 and (397.4 ± 8.2) mL in group B1, showing no significant difference (t=1.804, P=0.078); the blood loss was (1 046.9 ± 128.6) mL in group A2 and (494.4 ± 97.7) mL in group B2, showing significant difference (t=14.660, P=0.000). All 80 patients were followed up 2 years to 2 years and 6 months (mean, 2 years and 3 months) with satisfactory results in spinal cord decompression and reduction, and bony fusion was achieved at 12 months. There was no significant difference in the vertebral canal volume, vertebral height, and Cobb angle at both pre- and postoperation between 2 groups (P gt; 0.05). No loosening or breakage of screws and rods occurred. At 12 months after operation, the cure rates were 47.83% (11/23) in group A1 and 19.05% (4/21) in group B1, showing significant difference (χ2=4.046, P=0.044); the cure rates were 12.50% (2/16) in group A2 and 10.00% (2/20) in group B2, showing no significant difference (χ2=0.056, P=0.813). There was no significant difference (χ2=0.024, P=0.878) in the cure rates in the patients at grades A and B before operation between group A (12.50%, 3/24) and group B (11.11%, 3/27); but there was significant difference (χ2=5.992, P=0.014) in the cure rates in the patients at grades C and D before operation between group A (66.67%, 10/15) and group B (21.43%, 3/14). Conclusion Emergency operation of posterior pedicle screw-rod system for treatment of thoracolumber spine fracture and dislocation with spinal cord injury can provide good reduction, rigid fixation, and high fusion rate, so it is asafe and effective treatment method.
Objective To explore and evaluate the accuracy and feasibil ity of individual rapid prototype (RP) drill templates for atlantoaxial pedicle screw implantation. Methods Volumetric CT scanning was performed in 8 adult cadaveric atlas and axis to collect Dicom format datas. Then three-dimensional (3D) images of atlas and axis were reconstructed and the parameters of pedicles of 3D model were measured by using software Mimics 10.01. The 3D model was saved by STLformat in Mimics. The scattered point cloud data of 3D model were processed and the 3D coordinate system was located in software Imageware 12.1. The curves and surfaces of 3D model were processed in software Geomagic Studio 10. The optimal trajectory of pedicle screw was designed and a template was constructed which accorded with the anatomical morphology of posterior arch of atlas and lamina of axis by using software Pro/Engineer 4.0. The optimal trajectory of pedicle screw and the template were integrated into a drill template finally. The drill template and physical models of atlas and axis were manufactured by RP (3D print technology). The accuracy of pilot holes of drill templates was assessed by visually inspecting and CT scanning. Results The individual drill template was used conveniently and each template could closely fit the anatomical morphology of posterior arch of atlas and lamina of axis. Template loosening and shifting were not found in the process of screw implantation. Thirty-two pedicle screws were inserted. Imaging and visual inspection revealed that the majority of trajectories did not penetrate the pedicle cortex, only 1 cortical penetration was judged as noncritical and did not injury the adjacent spinal cord, nerve roots, and vertebral arteries. The accuracy of atlas pedicle screw was grade 0 in 15 screws and grade I in 1 screw, and the accuracy of axis pedicle screw was grade 0 in 16 screws. Conclusion The potential of individual drill templates to aid implantation of atlantoaxial pedicle screw is promising because of its high accuracy.
【Abstract】 Objective To explore the clinical application and outcomes of preoperative second measurement of three-dimensional (3-D) CT reconstruction data for scoliosis orthopedic surgery. Methods Between August 2006 and March 2008, 11 patients with severe rigid scoliosis received surgery treatment, including 4 males and 7 females with an average age of 17.2 years (range, 15-19 years). Preoperative second measurement of 3-D CT reconstruction data was conducted to guide the surgery， including the angle and width of pedicle, the entry point, and the choice of screws whose lengths and diameters were suitable. A total of 197 pedicle screws were implanted. The operation time， blood loss， postoperative nerve function，and Cobb’s angles at sagittal and coronal view were all recorded， and the postoperative CT scan was performed to assess the accuracy of pedicle screw insertion according to Andrew classification. Results Pedicle screws were implanted within 1-11 minutes (mean, 5.8 minutes), and the blood loss was 450-2 300 mL (mean, 1 520 mL). The postoperative X-ray films showed the correction rates of Cobb’s angle were 68.5% in coronal view and 55.5% in sagittal view. The accuracy of pedicle screw insertion was rated as grade I in 77 screws (39.1%)，grade II in 116 screws (58.9%)， and grade III in 4 screws (2.0%) according to postoperative CT scan. All 11 cases were followed up 14 months to 2 years without any complications. Conclusion Preoperative second measurement of 3-D CT reconstruction data can make the surgery process easy and accurate in treatment of severe scoliosis.
【Abstract】 Objective To investigate the clinical significances of the thoracic pedicle classification determined by inner cortical width of pedicle in posterior vertebral column resection (PVCR) with free hand technique for the treatment of rigid and severe spinal deformities. Methods Between October 2004 and July 2010, 56 patients with rigid and severe spinal deformities underwent PVCR. A total of 1 098 screws were inserted into thoracic pedicles at T2-12. The inner cortical width of the thoracic pedicle was measured and divided into 4 groups: group 1 (0-1.0 mm), group 2 (1.1-2.0 mm), group 3 (2.1-3.0 mm), and group 4 (gt; 3.1 mm). The success rate of screw-insertion into the thoracic pedicles was analyzed statistically. A new 3 groups was divided according to the statistical results and the success rate of screw-insertion into the thoracic pedicles was analyzed statistically again. And statistical analysis was performed between different types of thoracic pedicles classification for pedicle morphological method by Lenke. Results There were significant differences in the success rate of screw-insertion between the other groups (P lt; 0.008) except between group 3 and group 4 (χ2=2.540，P=0.111). The success rates of screw-insertion were 35.05% in group 1, 65.34% in group 2, and 88.32% in group 3, showing significant differences among 3 groups (P lt; 0.017). According to Lenke classification, the success rates of screw-insertion were 82.31% in type A, 83.40% in type B, 80.00% in type C, and 30.28% in type D, showing no significant differences (P gt; 0.008) among types A, B, and C except between type D and other 3 types (P lt; 0.008). In the present study, regarding the distribution of different types of thoracic pedicles, types I, II a, and II b thoracic pedicles accounted for 17.67%, 16.03%, and 66.30% of the total thoracic pedicles, respectively. The type I, II a, and II b thoracicpedicles at the concave side accounted for 24.59%, 21.13%, and 54.28%, and at the convex side accounted for 10.75%, 10.93%, and 78.32%, respectively. Conclusion A quantification classification standard of thoracic pedicles is presented according to the inner cortical width of the pedicle on CT imaging: type I thoracic pedicle, an absent channel with an inner cortical width of 0-1.0 mm; type II thoracic pedicle, a channel, including type IIa thoracic pedicle with an inner cortical width of 1.1-2.0 mm, and type IIb thoracic pedicle with an inner cortical width more than 2.1 mm. The thoracic pedicle classification method has high prediction accuracy of screw-insertion when PVCR is performed.
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.
Objective To assess the cl inical significance of transpedicular screw insertion in lower cervical vertebra assisted by multi-spiral CT (MSCT) three dimentional (3D) image reconstruction techniques. Methods Eight cervical vertebra specimens were examined by MSCT, and the messages were sent to SGI02 Workstation; according to the parameter requirements of lower cervical pedicle fixation, by using post-process of volume rendering (VR) the condition was judged and multi-plannar reformation (MPR) was used to do individual analysis; and the ideal path of screw insertion was obtained andthe related parameters were measured. After preoperative plan being finished, referring to these measured parameters, 3.5 mm screws were inserted into C3-7 pedicles of these 8 specimens. After insertion of screws, MSCT scanning and 3D reconstruction were performed again to evaluate the accuracy of lower cervical pedicle screw inserting. From May 2007 to November 2009, 28 patients who received screw insertion in lower cervical spines were given MSCT scanning and 3D reconstruction to evaluate the illness situation, to confirm shortest fixation volumes, and to collect the parameters of aim pedicle screw insertion. Results The time of insertion for each screw was (392 ± 62) seconds. It was found that one pedicle was clausura (1.25%, 1/80) and five pedicle diameters in coronal view were less than 3 mm (6.25%, 5/80), which all were not fit for screw insertion. A total of 74 screws were placed successfully. One-time success rate of screw insertion was 95.95% (71/74). The total accuracy rate was 91.89% (68/74). Six screws penetrated (8.11%). According to the Richter penetrating classification: grade one was 6.76% (5/74) and grade two was 1.35% (1/74). There were significant differences (P lt; 0.05) in penetrated rate between our study and anatomic landmark local ization (47.37%), Miller methods (25.00%), and there was no significant difference (P gt; 0.05) when compared with Abumi method (6.70%), hopper method (7.10%), pipel ine deoppilation method (5.20%) and navigation technique (11.30%). In cl inical 28 cases, 121 screws were inserted; one pedicle was clausura and one was fissure fracture, which all were unfit for insert screw in preoperative plan, the surgery project was adjusted. After operation, 17 patients (76 screws) were given MSCT scanning again. A total of 67 screws (88.16%) were placed successfully. Nine screws (11.84%) penetrated, grade one was 7.89% (6/76) and grade two was 3.95% (3/76). Conclusion It is accurate to apply MSCT 3D reconstruction techniques to measure the ideal screw canal in preoperative individual ized plan. Strictly following individual quantitative data, the safety and accuracy of the surgery can be improved. And it is feasible and available to use MSCT MPR imaging to evaluate the accuracy of pedicle screw insertion.
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.
