ObjectiveTo investigate the security of pedicle screw fixation in fractured vertebra in treatment of thoracolumbar fractures by comparing with routine fixation cross fractured vertebra. MethodsA total of 101 cases of single segmental thoracolumbar fracture were selected between June 2008 and June 2011. Of them, 56 cases underwent pedicle screw fixation in fractured vertebra (group A), and 45 cases received routine fixation cross fractured vertebra (group B). There was no significant difference in gender, age, causes of injury, fracture type, fracture segment, Frankel grading, time of injury to operation, and the preoperative anterior vertebral height compression ratio and the canal occupation rate between 2 groups (P>0.05). There were 34 cases of junction fracture of pedicle and vertebra (type I), 2 cases of pedicle waist fracture (type Ⅱ), and 20 cases of junction fracture of pedicle and lamina (type Ⅲ) in group A. The position of fractured vertebral pedicle screw was observed; the anterior vertebral height compression ratio, canal occupation rate, and surgical complications were compared between 2 groups. ResultsA total of 103 pedicle screws were placed in 54 patients of group A, except 2 patients of type Ⅱ fracture; 96 screws were placed in the bone cortex completely and 7 screws deviated. The operation time of group A was significantly longer than that of group B (t=4.339, P=0.000), but there was no significant difference in intraoperative blood loss between 2 groups (t=-0.089, P=0.929). All 101 patients were followed up 6-16 months (mean, 8.5 months). The patients of 2 groups achieved nerve functional recovery. Fixation-related complications occurred in 1 case of 2 groups respectively, showing no significant difference (P=1.000). At last follow-up, according to Denis lumbago classification, 51 cases were rated as P1 level and 5 cases as P2 level in group A; 35 cases were rated as P1 level, 8 cases as P2 level, and 2 cases as P3 level in group B; and there was no significant difference between 2 groups (Z=-1.836, P=0.066). There was no significant difference between 2 groups in canal occupation rate at immediate after operation and at last follow-up (P>0.05), and in the anterior vertebral height compression ratio at immediate after operation (P>0.05), but the anterior vertebral height compression ratio of group B was significantly higher that of group A at last follow-up (P<0.05). ConclusionSingle segmental thoracolumbar fracture treated by pedicle screw fixation in fractured vertebra through posterior approach is safe and feasible according to different pedicle fracture types to guide fixation.
Objective To investigate the effectiveness of posterior intrasegmental fixation with pedicle screw-lamina hook system and bone grafting for lumbar spondylolysis. Methods Between January 2005 and October 2009, 22 patients with lumbar spondylolysis underwent posterior intrasegmental fixation with pedicle screw-lamina hook system and bone grafting. There were 19 males and 3 females with an average age of 18.4 years (range, 12-26 years). The main symptom was low back pain with an average disease duration of 16 months (range, 8-56 months). The visual analogue scale (VAS) was 6.0 ± 1.2 and Oswestry disability index (ODI) was 72.0% ± 10.0% preoperatively. The X-ray films showed bilateral spondylolysis at L4 in 9 cases and at L5 in 13 cases. The range of motion (ROM) at upper and lower intervertebral spaces was (11.8 ± 2.8)°and (14.1 ± 1.9)°, respectively. ResultsAll incisions healed by first intention. All patients were followed up 12-45 months (mean, 25 months). Low back pain was significantly alleviated after operation. The VAS score (0.3 ± 0.5) and ODI (17.6% ± 3.4%) were significantly decreased at last follow-up when compared with preoperative scores (P lt; 0.05). CT showed bone graft fusion in the area of isthmus defects, with no loosening or breaking of internal fixator. At last follow-up, the lateral flexion-extension X-ray films of the lumbar spine showed that the ROM at upper and lower intervertebral spaces was (12.3 ± 2.1)°and (13.5 ± 1.7)°, respectively; showing significant differences when compared with preoperative values (P lt; 0.05). Pain at donor site of iliac bone occurred in 1 case, and was cured after pain release treatment. ConclusionThe posterior intrasegmental fixation with pedicle screw-lamina hook system and bone grafting is a reliable treatment for lumbar spondylolysis, having a high fusion rate, low complication rate, and maximum retention of lumbar ROM.
【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.
Objective To investigate the efficacy of the pedicle screw fixation and allograft bone in posterior spinal fusion for the treatment of thoracolumbar vertebral fractures. Methods From September 2006 to March 2008, 105 cases of thoracolumbar vertebral fractures were treated with allograft bone in posterior spinal fusion after the pedicle screw fixation,including 75 males and 30 males aged 15-65 years (mean 37 years). The mixture which consisted of spinous process and vertebral plate sclerotin and homogeneity variant bone was used as bone graft to implant into articular process and processus transversus space or vertebral plate space. The time from injury to surgery varied from 8 hours to 21 days, with an average of 3 days. There were 52 cases of fall ing injuries from height, 35 cases of traffic accident injuries, 11 cases of bruise injuries and 7 cases of tumbl ing injuries. Before operation, the primary cl inical symptoms of patients included local pain combined with l imitation of activity, 30 cases compl icated by various degrees of spinal cord and nerve root functional disturbance. According to Mcaffee classification, there were 7 cases of flexion depressed fractures, 86 cases of blow-out fractures, 9 cases of Chance fractures and 3 cases of dislocation-fracture. According to Frankel grade, there were 11 cases of grade A, 2 cases of grade B, 7 cases of grade C, 10 cases of grade D and 75 cases of grade E. The X-ray examination of all patients denoted that the bodies of injuryed vertebra were compressed and wedge-shaped, and the CT scan showed that 98 cases had spinal stenosis. After 2 weeeks and 3, 6, 12 months, the X-ray films were taken to evaluate bone graft fusion. The Cobb angle was measured. The recovery of nerve function was analyzed. Results The operation time was 55-180 minutes (mean 90 minutes) and the blood loss was 100-900 mL (mean 200 mL). All patients achieved heal ing by first intention with no compl ication. After operation, 93 cases were followed up for 6-15 months with an average of 11 months. Except for 11 patients who were at grade A before operation, one to two grade recover was observed in other patients. The average Cobb angle of injury segment was improved from preoperative 32.1° to postoperative 5.2°. The height of anterior border of injuried vertebral body was recovered from the preoperative average compressed remaining height 61.5% to postoperative 96.8%. The vestigial degree of canal is spinal is anteroposterior diameter was recovered from preoperative 65.7% to postoperative 89.9%. Imageology examination showed that all the patient achieved bone union within 6 months. The fusion rate of bone graft in spinal fusion was 100%. No loosening and breaking of nails occurred. Conclusion Pedicle fixators can restore and fix the thoracolumbar fractures, and the combination of autograft and allograft bone transplantation is a safe, rel iable and effective method.
ObjectiveTo systematically review the efficacy of at the fracture level (AFL) versus cross the fracture level (CFL) short-segment pedicle screw fixation for thoracolumbar fractures. MethodsWe electronically search PubMed, The Cochrane Library (Issue 8, 2015), EMbase, CBM, CNKI, VIP and WanFang data to collect randomized controlled trials (RCTs) of AFL versus CFL short segment pedicle screw fixation for thoracolumbar fractures from inception to Aug. 2015. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Meta-analysis was performed using RevMan 5.3 software. ResultsA total of 11 RCTs involving 730 patients were included. The results of meta-analysis indicated that: compared with the CFL group, the AFL group had more blood loss (MD=9.8, 95%CI 7.40 to 12.20), less implant failure rate (RR=0.19, 95%CI 0.07 to 0.48), lower long term postoperative VAS score of thoracolumbar pain (MD=-1.20, 95%CI -1.85 to -0.56), higher correction in short term postoperative kyphotic Cobb angle (MD=3.56, 95%CI 2.25 to 4.87), smaller value in long term postoperative kyphotic Cobb angle and its loss of correction (MD=-3.95, 95%CI -7.78 to -0.12; MD=-4.65, 95%CI -6.91 to -2.40), smaller degree of anterior vertebral height compression in short and long term postoperative (MD=-3.51, 95%CI -5.23 to -1.80; MD=-8.28, 95%CI -12.22 to -4.33), better result in long term postoperative anterior vertebral height and its loss of correction (MD=8.00, 95%CI 3.85 to 12.15; MD=-6.06, 95%CI -7.68 to -4.44). There were no significant differences between two groups regarding operation time, infectious complications and short term postoperative kyphotic Cobb angle (MD=0.11, 95%CI -5.36 to 5.57; RR=0.55, 95%CI 0.11 to 2.85; MD=-0.66, 95%CI -2.19 to 0.87). ConclusionCurrent evidence shows that AFL short-segment pedicle screw fixation for thoracolumbar fractures is superior to CFL fixation. Due to limited quality and quantity of the included studies, more high quality studies are needed to verify the above conclusion.
Objective To evaluate the deviation between actual and simulated screw placement after cervical pedicle screw placement assisted by 3D printed navigation template, and analyze the correlation between screw placement deviation and navigation pipe length. Methods A total of 40 patients undergoing cervical 1-7 pedicle screw insertion assisted by 3D printed navigation template in Zigong Fourth People’s Hospital between February 2018 and August 2020 were included in this prospective study. These patients were divided into 3 groups randomly, including 12 patients with a 5-mm pipe length (5 mm group), 13 patients with a 10-mm pipe length (10 mm group), and 15 patients with a 15-mm pipe length (15 mm group). Three-dimensional modeling was performed on preoperative cervical CT images of these patients and simulated pedicle screw was placed. Individualized pedicle screw navigation templates were designed according to the position and direction of simulated pedicle screws, and 3D printing was performed on the cervical model and navigation templates. Preoperative 3D printed model and navigation templates were used to simulate the surgical process to confirm the safety of screws. During the operation, pedicle screw placement was performed according to the preoperative design and simulated surgical process. The postoperative CT images were registered with the preoperative CT images in 3D model. The safety of screw placement was evaluated by the postoperative screw placement Grade, and the accuracy of screw placement was evaluated by measuring the deviation of screw placement point and the deviation of screw placement direction in horizontal plane (inclination angle) and sagittal plane (head inclination angle). The influence of different navigation pipe lengths on the safety and accuracy of screw placement was analyzed. Results A total of 164 pedicle screws were inserted with navigation template assistance, including 48 screws (38 in Grade 0 and 10 in Grade 1) in the 5 mm group, 52 screws in the 10 mm group (all in Grade 0), and 64 screws (52 in Grade 0 and 12 in Grade 1) in the 15 mm group, and the difference in the grade among the three groups was statistically significant (P<0.05). When the navigation pipe length was 5, 10, and 15 mm, respectively, the screw entry point deviation was (1.87±0.63), (1.44±0.63), and (1.66±0.54) mm, respectively, the inclination angle deviation was (2.72±0.25), (0.90±0.21), and (1.84±0.35)°, respectively, and the head inclination angle deviation was (8.63±1.83), (7.15±1.38), and (8.24±1.52)°, respectively. The deviations in the 10 mm group were all significantly less than those in the other two groups (P<0.05). Conclusions In the cervical pedicle screw placement assisted by navigation template, all the screws were Grade 0 or Grade 1, with high safety. The mean deviation of the screw entry point is within 2 mm, with high accuracy. When the length of navigation pipe is 10 mm, the safety and accuracy of screw placement can be fully guaranteed.
Objective To elucidate the new development and effects of three-dimensional correction techniques of idiopathic scol iosis (IS). Methods The related home and abroad l iterature concerning three-dimensional correction techniques of IS was extensively reviewed. Results With more and more attention to three-dimensional correction of IS, all kinds of surgery and developed techniques of correction are applied to the correction of IS. The effects of three-dimensional correction of IS are satisfied. Conclusion With more knowledge about IS and more developed theory of correction, more safe and effective techniques of correction is therefore the hot spot for future study.
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.
【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.
ObjectiveTo investigate the distance between the screw-out point and the middle sacral artery, and evaluate the safety when the S1 pedicle screw placed by the three cortical fixation techniques.MethodsFrom March to June 2018, randomized CT scan data of 98 adult pelvic angiography were selected to measure the distance from the middle sacral artery to the anterior edge of the vertebral body (a) and the distance from the middle sacral artery to the midline of the vertebral body (b). S1 screw entry point was set as the intersection of lines where extension of S1 facet joint inferior margin and lateral margin cross over. Introversion angles of 10, 15, 20, and 25° were used; the distance between the screw insertion point and the middle sacral artery (d) was measured.ResultsThe middle sacral artery was usually located on the left side of the upper endplate plane of S1. The distance a was (5.40±2.95) mm in 49 males and (4.43±2.32) mm in 49 females, and the difference between the males and females was not statistically significant (t=1.818, P=0.72). The distance b was (12.07±5.42) mm in 45 males and (14.12±4.88) mm in 48 females, and the difference between the males and females was not statistically significant (t=–1.914, P=0.59). The distance d was (12.67±6.00), (9.40±5.17), (7.50±3.76), and (8.10±3.64) mm when the nail was placed at a common internal inclination of 10, 15, 20, and 25°. The differences in the distance d at a common internal inclination of 10° vs. 15°, 10° vs. 20°, 10° vs. 25°, and 15° vs. 20° were all statistically significant (t=16.828, 11.609, 6.073, 6.254; P<0.008 3); there was no statistically significant difference in that at 15°vs. 25°, or 20° vs. 25° (t=2.034, –1.723; P>0.05).ConclusionBy analyzing the relationship between the middle sacral artery and the upper endplate plane of the S1 vertebra, the risk of middle artery injury is small while the biomechanical stability of the screw is increased when using the Lenham method.