Objective To evaluate the effectiveness of percutaneous puncture of thoracolumbar vertebral pedicle assisted by mixed reality technology based on multi-point registration algorithm. Methods The operator used two methods, namely MR-assisted puncture (a self-developed MR calibration method based on multi-point registration algorithm combined with MR head mounted equipment) and manual puncture, to perform percutaneous puncture of the thoracolumbar pedicle on the spinal prosthesis model. The distance between the first blind puncture point and the preset nail center point, and single registration and puncture time were compared among different puncture methods. Results Four operators completed a total of 48 MR-assisted punctures and 48 manual punctures. The deviation distance of MR-assisted puncture [(1.69±0.29) vs. (4.99±2.06) mm], registration and puncture time [(131.41±5.35) vs. (475.98±65.26) s] were all better than manual puncture (P<0.05). Conclusion The prosthetic model data shows that MR technology-assisted puncture based on multi-point registration algorithm can improve the accuracy and efficiency of percutaneous puncture of thoracolumbar vertebral pedicle compared to traditional manual puncture.
ObjectiveTo investigate the effectiveness of modified direction-changeable lumbar Cage in transforaminal lumbar interbody fusion (TLIF).MethodsA retrospective analysis was made of 161 patients with single segment L4 or L5 isthmic spondylolisthesis treated between January 2013 and December 2015. According to the implantation of Cage, they were divided into trial group (85 cases, modified direction-changeable lumbar Cage implanted in TLIF) and control group (76 cases, traditional nondirection-changeable Cage implanted in TLIF). There was no significant difference in the general data of gender, age, disease duration, slippage segment, and slippage grade between the two groups (P>0.05). The intraoperative implantation time of Cage, Cage position adjustments times, fluoroscopy times during implantation of Cage, fluoroscopy exposure time, and total operation time were recorded and compared between the two groups. Visual analogue scale (VAS) and Oswestry disability index (ODI) scores were used to evaluate the effectiveness of the patients before operation, and at 3, 6, and 12 months after operation, and the incidence of complications was recorded and analyzed. CT examinations were performed at 6 and 12 months after operation, and lumbar fusion was evaluated by Bridwell criteria.ResultsThe intraoperative implantation time of Cage, Cage position adjustments times, fluoroscopy times during implantation of Cage, fluoroscopy exposure time, and total operation time in trial group were significant less than those in control group (P<0.05). All the 161 patients were followed up 12-18 months (mean, 14.3 months). There was 1 case of dural sac tear in the trial group and 1 case of superficial infection in the control group; no complication such as dural tear and infection occurred in other patients. The fusion rate was 76.5% (64/85) in the trial group and 57.9% (44/76) in the control group at 6 months after operation, showing significant difference (χ2=6.44, P=0.02); at 12 months after operation, the fusion rate was 96.5% (82/85) in the trial group and 90.8% (69/76) in the control group (including 3 cases of Cage displacement and 4 cases of screw breakage), showing no significant difference in the fusion rate between the two groups (χ2=1.54, P=0.26). The VAS and ODI scores of the two groups decreased gradually at 3, 6, and 12 months after operation, and improved significantly when compared with those before operation (P<0.05). There was no significant difference in VAS and ODI scores between the two groups before and after operation (P>0.05).ConclusionBoth Cages can obtain the similar effectiveness. The modified direction-changeable lumbar Cage can significantly reduce the fluoroscopy times and radiation dose during TLIF, shorten the operation time, and effectively reduce the radiation exposure of patients and medical staff.
ObjectiveTo explore the effectiveness of pedicle screw fixation combined with non-fusion technology for the treatment of thoracolumbar fracture (AO type A) through Wiltse paraspinal approach. MethodsBetween March 2011 and December 2012, 35 cases of thoracolumbar fractures were treated with pedicle screw fixation combined with non-fusion technology by Wiltse paraspinal approach. There were 27 males and 8 females, aged from 19 to 51 years (mean, 39.7 years). The time from injury to operation varied from 3 to 15 days (mean, 5.9 days). The causes of injury were traffic accident in 17 cases, falling from height in 11 cases, and crush trauma in 7 cases. All fractures were single-segment fracture, including T8 in 1 case, T9 in 2 cases, T10 in 2 cases, T11 in 3 cases, T12 in 12 cases, L1 in 10 cases, L2 in 4 cases, and L3 in 1 case. According to AO classification, there were 17 type A1 fractures (compression fracture), 3 type A2 fractures (splitting fracture), and 15 type A3 fractures (burst fracture). Based on American Spinal Injury Association (ASIA) spinal cord injury grade, all cases were in grade E before operation. Perioperative parameters were recorded; the anterior vertebral height and kyphotic Cobb angle of vertebral bodies were measured before and after operation to evaluate the effect of correction. ResultsThe mean operating time was 74 minutes; the mean blood loss was 125 mL; and the mean drainage volume was 51 mL. Skin necrosis of incision occurred in 2 cases and was cured after dressing change; primary healing of incision was obtained in the others. All patients were followed up 15-24 months (mean, 17.3 months). No loosening or breakage of internal fixation was found. The internal fixator was removed at 12-19 months after operation (mean, 15 months). There were significant differences in Cobb's angle and anterior vertebral body height between before operation and immediately after operation, before internal fixator removal as well as at last follow-up (P < 0.05). There was no significant difference in anterior vertebral body height among the postoperative time points (P > 0.05). There was significant difference in Cobb's angle between immediately after operation and before internal fixator removal as well as at last follow-up (P < 0.05), but the difference was not significant between before internal fixator removal and at last follow-up (P > 0.05). The motion of fixed segment was restored after internal fixator removal. ConclusionIt is an effective method of pedicle screw fixation combined with non-fusion technology through Wiltse paraspinal approach for the treatment of thoracolumbar fracture (AO type A). The method has the advantages of simple operation and less trauma. It can effectively rebuild the height of vertebral body and correct kyphotic deformity.
Objective To study the properties of the xenogeneic deproteinized cancellous bone used as a scaffold in the bone tissue engineering andits application to the spinal fusion of the lumbar intertransverse process in agoat. Methods The deproteinized bone was derived from an adult pig’s femoral cancellous bone through the physical and chemical treatments. Its morphological features, constituting components, and biomechanical properties were examined by the scanning electron microscopy, X-ray diffraction analysis, and mechanical experimental instrument. The cell-material complex was observed under the inverted phase contrast microscope to evaluate the adhesion and the growth of the osteoblasts. The experimental model of the spinal fusion of the lumbar intertransverse process was produced in 12 male goats aged 6-8 months, which were divided into two groups. In Group A, the tissue engineered bone constructed by thexenogeneic deproteinized cancellous bone, the recombinant human bone morphogenetic protein 2, and the mesenchymal stem cells was used for the spinal fusion; however, in Group B the autoilium was used. The samples were harvested at 4, 8 and 12 weeks postoperatively, and a series of examinations were performed, including the radiography and the histomorphological assay. Results The deproteinized cancellous bone had a natural pore network system, with an aperture ranging in size from 200 to 500 μm, containing a main organic material ofcollagen and the inorganic material of hydroxyapatite. So, the deproteinized cancellous bone had a good mechanical strength and a good histocompatibility. In Group A, the X-ray examination at different timepoints postoperatively showed that at 4 weeks,the bridging areas of all the fusion sites were not clear, especially on the internal side; at 8 weeks, the upper and lower bridged parts had a narrowed gap, with formation of much continuous bony callus; at 12 weeks, a complete fusion occurred. In the early stage, the material density was slightly lowerin Group A than in Group B, but at 12 weeks the density was almost the same in both the groups. Histological examination in the transplant area showed that at 4 weeks in Group A there was a new bone formation in a multipoint way; at 8 weeks, a “sandwichshaped” new bone wascrossed with the transplanting materials; and at 12 weeks, a medullary cavity was remodeled and a new cancellous bone was formed. The osteogenic process of thetissue engineered bone constructed by the xenogeneic deproteinized cancellous bone scaffold was almost the same as the autoilium osteogenesis. Conclusion The xenogeneic deproteinized cancellous bone is a good material in the bone tissue engineering, which can be used as an osteogenesis scaffold andprovide a stable environment for revascularization and osteoblastic differentiation.
Objective To explore the effectiveness of percutaneous pedicle screw fixation on the indirect reduction of posterosuperior fracture fragment in the thoraculumbar burst fractures. Methods Patients with thoracolumbar fractures treated in the Fourth People’s Hospital of Zigong from September 2017 to September 2019 were collected retrospectively. All patients were treated with percutaneous pedicle screw fixation. The main observation indexes before operation, 3 days after operation and 1 year after operation were compared, including the height ratio of the anterior margin of fractured vertebra, the inversion angle of posterosuperior fracture fragment, the fragment displacement, the occupancy rate of spinal canal, the Cobb angle of kyphosisat, Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI). Results A total of 38 patients were included. All patients were followed up for more than 1 year. During the follow-up period, there were no complications such as nerve injury, incision infection, internal fixation loosening or fracture. The operation time was (91.7±10.4) min, the amount of intraoperative bleeding was (94.3±19.5) mL, and the length of surgical incision was (9.3±1.8) cm. The height ratio of the anterior margin of fractured vertebra, the inversion angle of posterosuperior fracture fragment, the fragment displacement, the occupancy rate of spinal canal, the Cobb angle of kyphosisat 3 days after operation were significantly improved compared with those before operation (P<0.05); the height ratio of the anterior margin of fractured vertebra, the occupancy rate of spinal canal, and the Cobb angle of kyphosisat 1 year after operation were also significantly improved compared with those before operation (P<0.05); the height ratio of the anterior margin of fractured vertebra and the occupancy rate of spinal canalat 1 year after operation were significantly improved than those 3 days after operation (P<0.05), but the Cobb angle of kyphosis 1 year after operation was significantly lost than that 3 days after operation (P<0.05). The VAS score and ODI index 3 days and 1 year after operation were significantly improved compared with those before operation (P<0.05), and the VAS score and ODI index 1 year after operation were improved compared with those 3 days after operation (P<0.05). Conclusion The percutaneous pedicle screw fixation can effectively reduce the retropulsed bone fragment indirectly and restore the Cobb angle of kyphosis of the thoraculumbar burst fractures without neurological deficit, and at the same time reduce the operation time and surgical trauma.
Objective To analyze the imaging characteristics of vertebral " shell” phenomenon of thoracolumbar fractures after posterior reduction and to explore the relationship between vertebral " shell” and fracture healing. Methods Between January 2013 and December 2015, the clinical data of 116 patients with thoracolumbar fractures treated with posterior pedicle screw-rod system reduction and internal fixation were analyzed retrospectively. There were 72 males and 44 females, aged 22-66 years (mean, 43 years). Injury causes were traffic accident in 24 cases, falling from height in 54 cases, bruise in 38 cases. Fracture segment located at T11 in 5 cases, T12 in 38 cases, L1 in 52 cases, L2 in 21 cases. There were 51 cases of compressive fracture and 65 cases of burst fracture. The sagittal Cobb angle ranged from 8 to 27°, with an average of 15°. Degree of preoperative spinal compression ranged from 20% to 75%, with an average of 44%. Bone density measurement showed that normal bone mass in 30 cases, bone loss in 40 cases, osteoporosis in 41 cases, and severe osteoporosis in 5 cases. The number, pathological characteristics, and imaging regularity of the vertebral " shell” phenomenon were observed and analyzed by logistic regression. Results All patients were followed up 11-18 months with an average of 13 months. A total of 72 cases of vertebral " shell” phenomenon mainly located in the vertebral anterior column and the end plate near the weak area (54/72, 75.0%). Most of them were in the irregular shape (50/72, 69.5%). The vertebral fracture line was related to the shape of the vertebral body and the displacement of the vertebral body after reduction. The outcome of the " shell” can be divided into disappeared type, reduced type, and collapse type, the volume of vertebral " shell” and its outcome were the risk factors for vertebral fracture healing. Conclusion The incidence of vertebral " shell” and nonuion of thoracolumbar fractures after posterior reduction are high. The main influencing factors are vertebral " shell” outcome and size.
Objective To compare the effectiveness between three-dimensional (3D) printed porous titanium alloy cage (3D Cage) and poly-ether-ether-ketone cage (PEEK Cage) in the posterior lumbar interbody fusion (PLIF). Methods A total of 66 patients who were scheduled to undergo PLIF between January 2018 and June 2019 were selected as the research subjects, and were divided into the trial group (implantation of 3D Cage, n=33) and the control group (implantation of PEEK Cage, n=33) according to the random number table method. Among them, 1 case in the trial group did not complete the follow-up exclusion study, and finally 32 cases in the trial group and 33 cases in the control group were included in the statistical analysis. There was no significant difference in gender, age, etiology, disease duration, surgical segment, and preoperative Japanese Orthopaedic Association (JOA) score between the two groups (P>0.05). The operation time, intraoperative blood loss, complications, JOA score, intervertebral height loss, and interbody fusion were recorded and compared between the two groups. Results The operations of two groups were completed successfully. There was 1 case of dural rupture complicated with cerebrospinal fluid leakage during operation in the trial group, and no complication occurred in the other patients of the two groups. All incisions healed by first intention. There was no significant difference in operation time and intraoperative blood loss between groups (P>0.05). All patients were followed up 12-24 months (mean, 16.7 months). The JOA scores at 1 year after operation in both groups significantly improved when compared with those before operation (P<0.05); there was no significant difference between groups (P>0.05) in the difference between pre- and post-operation and the improvement rate of JOA score at 1 year after operation. X-ray film reexamination showed that there was no screw loosening, screw rod fracture, Cage collapse, or immune rejection in the two groups during follow-up. At 3 months and 1 year after operation, the rate of intervertebral height loss was significantly lower in the trial group than in the control group (P<0.05). At 3 and 6 months after operation, the interbody fusion rating of trial group was significantly better in the trial group than in the control group (P<0.05); and at 1 year after operation, there was no significant difference between groups (P>0.05). ConclusionThere is no significant difference between 3D Cage and PEEK Cage in PLIF, in terms of operation time, intraoperative blood loss, complications, postoperative neurological recovery, and final intervertebral fusion. But the former can effectively reduce vertebral body subsidence and accelerate intervertebral fusion.
Objective To develop a deep learning system for CT images to assist in the diagnosis of thoracolumbar fractures and analyze the feasibility of its clinical application. Methods Collected from West China Hospital of Sichuan University from January 2019 to March 2020, a total of 1256 CT images of thoracolumbar fractures were annotated with a unified standard through the Imaging LabelImg system. All CT images were classified according to the AO Spine thoracolumbar spine injury classification. The deep learning system in diagnosing ABC fracture types was optimized using 1039 CT images for training and validation, of which 1004 were used as the training set and 35 as the validation set; the rest 217 CT images were used as the test set to compare the deep learning system with the clinician’s diagnosis. The deep learning system in subtyping A was optimized using 581 CT images for training and validation, of which 556 were used as the training set and 25 as the validation set; the rest 104 CT images were used as the test set to compare the deep learning system with the clinician’s diagnosis. Results The accuracy and Kappa coefficient of the deep learning system in diagnosing ABC fracture types were 89.4% and 0.849 (P<0.001), respectively. The accuracy and Kappa coefficient of subtyping A were 87.5% and 0.817 (P<0.001), respectively. Conclusions The classification accuracy of the deep learning system for thoracolumbar fractures is high. This approach can be used to assist in the intelligent diagnosis of CT images of thoracolumbar fractures and improve the current manual and complex diagnostic process.
ObjectiveTo compare the biomechanical differences between the kidney-shaped nano-hydroxyapatite/polyamide 66 (n-HA/PA66) Cage and the bullet-shaped n-HA/PA66 Cage. MethodsL2-L5 spinal specimens were selected from 10 adult male pigs. L2, L3 and L4, L5 served as a motor unit respectively, 20 motor units altogether. They were divided into 4 groups (n=5):no treatment was given as control group (group A); nucleus pulposus resection was performed (group B); bullet-shaped Cage (group C), and kidney-shaped Cage (group D) were used in transforaminal lumbar interbody fusion (TLIF) through left intervertebral foramen and supplemented by posterior pedicle screw fixation. The intervertebral height (IH) and the position of Cages were observed on the X-ray films. The range of motion (ROM) was measured. ResultsThere was no significant difference in the preoperative IH among 4 groups (F=0.166, P=0.917). No significant change was found in IH between at pre- and post-operation in group B (P>0.05); it increased after operation in groups C and D, but difference was not statistically significant (P>0.05). There was no significant difference in the postoperative IH among groups B, C, and D (P>0.05). The distance from Cage to the left margin was (3.06±0.51) mm in group C (close to the left) and (5.68±0.69) mm in group D (close to the middle), showing significant difference (t=6.787, P=0.000). The ROM in all directions were significantly lower in groups C and D than in groups A and B (P<0.05), and in group A than in group B (P<0.05). The right bending and compression ROM of group C were significantly higher than those of group D (P<0.05), but no statistically significant difference was found in the other direction ROM (P>0.05). ConclusionThe bullet-shaped and kidney-shaped Cages have similar results in restoring IH and maintaining the stability of the spine assisted by internal fixation. Kidney-shaped Cage is more stable than bullet-shaped Cage in the axial compression and the bending load opposite implant, it can be placed in the middle and back of the vertebral body more ideally.
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.