[Objective]To investigate the effect of atlanto-axial pedicle screw plate and fusion in treatment of upper cervical injuries. [Methods]Fifty-six cases of upper cervical spine injuries were treated with atlanto-axial pedicle screw plate and internal fixation,with total 200 screws,from March 2000 to September 2007.There were 36 males and 14 females,with an average age of 41.52 years(ranged,20~65 years).There were 23 cases of type II odontoid process fracture,12 cases of odontoid process nonunion,15 cases of transverse ligament injury.[Results]Greater occipital nerve pain occurred in 4 cases postoperatively and fully recovered after treatment 1 month later.The lateral cortical bone was penetrated by screws in 2 cases,without spinal cord or vertebral artery injury.Forty-eight cases were followed up for an average of 27.56 months(ranged,25~60 months).Bone fusion was achieved in all cases,without plate or screw broken.X-ray showed complete replacement of atlas and odontoid process of axis fracture.CT showed good position relation between screw and vertebral artery or spinal cord.According to JOA classification,excellent result was achieved in 34 cases,good in 13 cases,fair in 2 cases,poor in 1 case,with the good-to-excellent rate of 94.00%.[Conclusion]Atlanto-axial pedicle screw combined with plate fixation system is effective in treatment of upper cervical injuries.It can significantly improve the biomechanical stability of atlantoaxial joint,with high bone graft fusion rate.

BACKGROUND:The anatomic structures and kinetic characteristics are the bases to establish hand model, and the kinetic characteristics of hand are determined by the anatomic structure. So, numerous scholars have paid close attention to virtual hand models based on the anatomic structures of hand.OBJECTIVE: To construct visible hand model based on anatomic structure.DESIGN: Single sample trial.SETTING: Center Laboratory, Third Military Medical University of Chinese PLA.MATERIALS: This trial was carried out in the Center Laboratory, Third Military Medical University of Chinese PLA in October 2003. Two fresh adult hands, which involved wrist joint, provided by the Department of Anatomy, Third Military Medical University of Chinese PLA, were employed. The two hands had no organic damage by naked observation.METHODS: The specimens were embedded and mill-cut (mill-cut layer thinness 0.2 mm). Cannon (ESO 1OD) digital camera (6.3 million pixel) was used for image collection. Each image was 31.5 MB, Data of 1 200 images were obtained.Adobe Photoshop 7.0 software was used for image treatment and then two-dimensional cross-section images were collected. The bone, flexor tendon and the outline of hand was three-dimensionally reconstructed by using the software,which was developed by the Department of Computer Science and Technology,Tsinghua University and Institute of Computer Medicine, Department of Anatomy, Third Military Medical University of Chinese PLA.MATN OUTCOME MEASURES: Three-dimensional reconstruction of the bone, flexor tendon and outline of hand.RESULTS: ①The outline of hand: After being reconstructed, the outline, which consisted of all fingers and nails, was well displayed, and observed from many directions.② Three-dimensional reconstruction of the bone of hand: The reconstructed bones of hands involved digital bones, metacarpal bones, carpal bones and all joints, and they could be displayed solely or in groups with other reconstructed structures.③ Three-dimensional reconstruction of the flexor tendons of hand:Four superficial flexor tendons, four deep flexor tendons and one flexor pollex Iongus muscle tendon could be seen from the reconstructed images. All the flexor tendons went out together from the carpal canal and went through the palm, then spread out in fan-shape along the direction of each finger. ④ Three-dimensional reconstruction of the metacarpal fascial spaces: It could be observed from the reconstructed three-dimensional models that the proximal end of the thenar space was close, its distal end was open to the 1st web space, and the proximal end of the midpalmar fascial space was open to the posterior space of antebrachial flexor by carpal canal. Its distal end had three little spaces, which were open to the 2nd, 3rd and 4th web space, respectively.CONCLUSION: The visible hand model, which is preliminarily established, can precisely show the main anatomic structure of palm.

BACKGROUND:Bone cement solidification can improve the stability, strength and mechanical support of fractured vertebrae. However, there are few studies on the effect of bone cement dispersion within the fracture line on percutaneous vertebroplasty. OBJECTIVE:To analyze the effect of bone cement dispersion within the fracture line of thoracolumbar osteoporotic vertebral compression fractures on percutaneous vertebroplasty. METHODS:Totaly 90 patients with thoracolumbar osteoporotic vertebral compression fractures were enroled, 53-80 years old, including 42 males and 48 females. Al these patients underwent percutaneous vertebroplasty with bone cement injection, and divided into two groups according to bone cement dispersion conditions: study group with good bone cement dispersion (n=60) and control group with poor bone cement dispersion (n=30). Visual analogue scale scores, Oswestry dysfunction index, Cobb's angle and adverse reactions were recordedbefore and after treatment. RESULTS AND CONCLUSION:There were no differences in the visual analogue scale score and Oswestry dysfunction index between the two groups before treatment (P > 0.05). The visual analogue scale scores were significantly lower in the study group than the control group at 3 days after treatment and at the last folow-up (P < 0.05); the Oswestry dysfunction index and Cobb's angle were also lower in the study group than the control group at 3 days after treatment (P < 0.05). However, no difference was found in the Oswestry dysfunction index, Cobb's angle and bone cement leakage between the two groups at the last folow-up. These findings indicate that the percutaneous vertebroplasty show better effects on pain relief in patients with good bone cement dispersion that those with poor bone cement dispersion, and the vertebral stability is better as wel as the short-term effect is more obvious.

Objective To explore the clinical effect of the atlanto-axial pedicle screw internal fixation to reconstruct upper cervical spine instability. Methods Using atlanto-axial pedicle screw and internal fixation system combined with autogenous iliac bone graft to treat 21 patients with upper cervical spine instability. Type Ⅱ odontoid process old fracture was 13 patients, odontoid process nonunion was 5 patients, injury of the transverse ligament was 3 patients. They were placed in 84 atlanto-axial pedicle screws, autogenous bones were placed in the posterior arch of atlas and axis to fusion, so that atlanto-axial complex got stabilized. Results The left lateral cortical bone of atlas vertebral pedicle was broken by screws in 2 patients, but the spinal cord and vertebral artery was intact. X-ray film showed the atlas and the fracture of dens of axis was completely replaced in all patients. The position of screw and vertebral artery or spinal cord was good in CT image. According to JOA score standard, 15 cases of all were excellent, 3 cases were good,2 cases were common,1 case was bad, and the rate of excellent and good was 85.71%(18/21).Seventeen cases were followed up for 12-26 (12.83 ± 4.23) months, all patients had acquired bone fusion and found no screw and plate fracture. Conclusions Atlanto-axial pedicle screw combined with screw-plate system fixation to treat upper cervical spine instability, can significantly enhance the biomechanical stability of the atlanto-axial interbody, bone grafting fusion rate is higher, the application value of the atlanto-axialfusion is higher.

BACKGROUND : After femoral neck fracture, incidences of ischemic necrosis and bone non-healing are closely related to biomechanical characteristics of internal fixation devices. Compression stress can improve fracture healing, tension force can delay fracture healing, and shear stress can inhibit fracture healing. How to relieve shear stress and expand compression stress is of significance for theories and clinical applications.OBJECTIVE: To compare the biomechanical characteristics of the two geometric configurations of three cannulated compression screws in the fixation for femoral neck fracture and to provide a theoretical foundation in the treatment of femoral neck fracture.DESIGN : Observational contrast study.SETTING: Department of Orthopaedics, the 251 Hospital of Chinese PLA; Department of Orthopaedics, the Third Hospital, Hebei Medical University.PARTICIPANTS: The experiment was carried out in the Hebei Orthopaedic Institute from November 2002 to March 2003. Five cadavers including 4 males and 1 female with similar bone mineral density (BMD) were provided by Department of Anatomy, Hebei Medical University. X-ray photographs proved that all the cadavers did not have rheumatism, tuberculosis, tumor, fracture or deformity.METHODS: Ten femurs were randomly divided into inverted and upright isosceles triangle with 5 in each group. Femur samples with femoral neck fracture were fixed with three cannulated screws and measured with the biomechanical machine (CSS-44020, made in Changchun Experimental Researching Institute, provided by Hebei Orthopaedics Institute). The compression strength, torsibility and the maximal vertical loading were compared between the two configurations of screws.MAIN OUTCOME MEASURES:①Displacement of femoral head at 600 N and 750 N during torsibility test; ②torque-moment at 2°and 4°during torsibility test;③load during maximal vertical loading test.CONCLUSION: The effect of three cannulated compression screws configured as an inverted isosceles triangle on the treatment of femoral neck fracture is superior to that of three cannulated compression screws as an upright isosceles triangle.

BACKGROUND: The treatment of upper cervical spine disorders through a posterior pedicle fixation approach have been carried out in some domestic large hospitals, but this surgery is still considered as a difficulty of cervical spine surgery. In order to minimize the risk of surgery, the authors designed a program of individual operations, and combined with self-developed pedicle locating and directing speculum to determine precise intraoperative position of pedicle screws, and no report is found by searching related database in China.OBJECTIVE: To improve the one-time success rate of internal fixation screws, to investigate the biomechanical effect of the implant, to formulate a simple, practical, individual protocol for atiantoaxial pedicle screw-plate system based on related data. METHODS: A total of 31 patients were recruited from Department of Orthopaedics in the 251 Hospital of Chinese PLA, between January 2002 and September 2006. Under the guidance of self-made atlantoaxial locating and directing speculum, the entrance point and angle for screw insertion, as well as screw diameter and length were determined according to the results of X-ray and CT measurement. Atlas pedicle screw was inserted at left (19.93±1.32) mm, and right (19.16±1.3) mm; Atlas pedicle screw insertion angle to inside was left (23.72±2.09)°, and right (23.35±1.91)°; Atlas pedicle screw insertion angle to side of head was (9.00±1.20)°. Axis pedicle screw was inserted at left (13.14±0.82) mm, and right (13.85±0.79) mm; Axis pedicle screw insertion angle to inside was left (24.52±1.26)°, and right (20.42±1.42)°; Axis pedicle screw insertion angle to side of head was (25.00±3.00)°.RESULTS AND CONCLUSION: ①Totally 124 pedicle screws were implanted into 31 patients, and 122 screws were of one-time success. The precision rate was 98.39%. Two screws were secondly inserted because of cutting lateral cortical bone of pedicle for deviation of inward angle. ②Occipital neuralgia was found in 2 cases postoperatively and cured after one month of treatment;screws penetrated atlas left vertebral lateral wall in 2 cases, no spinal or vertebral artery injury was found. ③Radiographs showed that atlas was completely reduced in all patients, and apposition of dentoid process of axis fracture was good. CT films showed the screws a good location to the vertebrarterial spinal cord. ④The follow-up visit was averaged of 10.5 months. Bony fusion was found in all patients. No screw-plate breakage was found. No inflammatory or rejection reactions occurred.⑤By JOA scale, there were 16 cases of excellent, 12 cases of good, 2 cases of fine, and 1 case of poor. The excellent and good rate was 90%. It is suggested that the success rate of atlantoaxial pedicle screw-plate mplantation can be improved through a biomechanical angle.

Objective To investigate the clinical results of minimally invasive fixation of the sacroiliac triangle for vertically unstable pelvic posterior ring injury. Methods A retrospective study was conducted of 20 patients who had been treated for vertically unstable pelvic posterior ring from January 2014 to August 2016. They were 12 males and 8 females, aged from 20 to 58 years ( average, 35 years ) . According to Tile classification for pelvic fractures, there were 4 cases of type C1. 1, 6 cases of type C1. 2, 7 cases of type C1. 3 and 3 cases of type C2. Their posterior rings were treated by fixation through posterior paraspinal approach with S1-iliac pedicle screws plus percutaneous sacroiliac screws, and their anterior rings by closed reduction and internal fixation with cannulated screws, Infix or plate following open reduction. The incision length, operation time and intraoperative blood loss were recorded. Postoperative reduction quality was assessed by Matta radio-logical criteria and pelvic function by Majeed criteria at the final follow-ups. Results Altogether 20 fixation systems of S1-iliac pedicle screws and 37 sacroiliac joint screws were inserted in this series. The length of incision ranged from 5. 5 to 7. 6 cm ( average, 6. 2 cm ) , the operation time from 89 to 130 minutes ( average, 98 minutes) and the intraoperative blood loss from 110 to 320 mL (average, 195 mL). According to Matta ra-diological criteria, reduction was excellent in 13, good in 5 and fair in 2 cases, with an excellent and good rate of 90％. The follow-up time for the 20 patients ranged from 6 to 15 months ( average, 9 months ) . The healing time ranged from 10 to 14 weeks ( average, 12. 5 weeks ) . At the final follow-ups, X-ray and CT three-dimensional reconstruction showed fine fracture union. By the Majeed criteria, the pelvic function was excellent in 11 cases, good in 5, fair in 3, and poor in one, with an excellent and good rate of 80％. No loosening, breakage or pull-out of pedicle screws or sacroiliac screws happened. Conclusion Minimally invasive fixation of the sacroiliac triangle for vertically unstable pelvic posterior ring injury can lead to precise placement, quick recovery, small incision and good functional outcome.

Objective To evaluate the clinical efficacy of our self-made minimally invasive pelvic channel instrument in the treatment of pelvic ring fracture-dislocation.Methods A retrospective study was conducted of the 35 patients who had been treated for pelvic ring fracture-dislocation from December 2015 to November 2017 and fully followed up at Department I of Orthopaedis,Beijing Chaoyang Emergency Rescue Center.They were 25 males and 10 females,aged from 20 to 73 years (average,41.3 years).According to the Tile classification for pelvic fractures,there were 26 cases of type B (type B1 in 8,type B2 in 12 and type B3 in 6) and 9 cases of type C(type C1 in 5,type C2 in 3 and type C3 in 1).Infix or anterior plate combined with percutaneous internal fixation with sacroiliac cannulated screws was used in 11 patients,sacroiliac triangle fixation combined with percutaneous internal fixation with anterior ring cannulated screws in 5 ones,and internal fixation with cannulated screws for anterior and posterior rings in 19 ones.All the channels were established using our self-made minimally invasive pelvic channel instrument for internal fixation with cannulated screws.The time for each screw placement and the number of X-ray projection were recorded.Postoperative reduction,pelvic function at the final follows-ups and complications were recorded.Results A total of 84 cannulated screws were inserted in the 35 patients.The time for each cannulated screw placement ranged from 5 to 13 minutes (average,8.1 minutes);the number of X-ray projection for each screw placement ranged from 7 to 15 times (average,10.3 times).Postoperative CT showed that all the cannulated screws were located in the preset channels.According to the Matta radiological criteria,postoperative reduction quality was excellent in 29,good in 4 and fair in 2,giving a good to excellent rate of 94.3％.The follow-up time for the 35 patients ranged from 6 to 15 months (average,12.3 months).At the final follow-ups,all the patients showed fine fracture union.There was no loosening or breakage of screws in all but one patient in whom one sacroiliac screw became loose 3 months after surgery.By the Majeed criteria,the pelvic function was excellent in 27 cases,good in 5,fair in 3 and poor in one,giving a good to excellent rate of 91.4％.Conclusion Our self-made minimally invasive pelvic channel instrument can be used to establish pelvic channels,leading to more accurate placement,shorter operative time and less X-ray projection.

Objective To investigate the value of pelvic CT sagittal reconstruction for percutaneous insertion of iliosacral screws.Methods Data of 32 patients who had been treated for pelvic posterior ring injury from June 2015 to March 2017 were retrospectively analyzed.There were 21 males and 7 females,aged from 21 to 75 years (average,43.2 years).According to Tile classification for pelvic fractures,there were 23 cases of type B (type BI in 4,type B2 in 13 and type B3 in 6),and 9 cases type C (type C1 in 6,type C2 in 2 and type C3 in 1).The pelvic CT three-dimensional reconstruction was performed before operation,and the reconstructed layer of CT sagittal position was overlapped,and preset S1,S2 sacroiliac joint hollow.Insert the screws according to the preset needle point and passage under the perspective of C-arm X-ray machine during the operation.In 32 cases of patients,3 cases of type C1,1 case of type C2 and 1 case of type C3 fractures in sacroiliac joint hollow combined with S1-ilium pedicle screw internal fixation,and the rest of 27 patients were treated by iliosacral screws.The time for each screw placement and the times of X-ray projection were recorded.The position of cannulated screw was observed by CT scan and compared with the preset channel after the operation.Postoperative reduction quality was assessed using Matta radiological criteria and Majeed criteria was used at the final follow-ups to evaluate the pelvic function.Results The operations time was ranged from 40 to 240 min (average,130 min);and the blood loss was ranged from 20 to 150 ml (average,80 ml).Altogether 58 iliosacral screws were inserted in 32 patients.The time for each screw placement was ranged from 5 to 15 min (average,9.5 min);and the number for each screw X-ray projection was ranged from 7 to 15 times (average,10.2 times).Postoperative CT scan and vascular ultrasound showed that all the iliosacral screws did not penetrate the cortical bone or damaged the vascular nerves,and the error of the preset channel was from 0 to 5 mm (average,2.2 mm).All fractures healed successfully,and the healing time was 12 to 18 weeks (average,14.2 weeks).According to Matta radiological criteria,reduction was excellent in 26,good in 3 and fair in 3,with an excellent to good rate of 90.6％ (29/32).The follow-up time for the 32 patients was ranged from 6 to 15 months (average,11.3 months).At the latest follow-ups,Xray and CT examination showed fine fracture union and no loosening or breakage of screws in all.By the Majeed criteria,the pelvic function was excellent in 21 cases,good in 8 cases,fair in 3 cases,with a good to excellent rate of 90.6％ (29/32).Conclusion Preoperative pelvic CT sagittal reconstruction for preset of iliosacral screw insertion point,angle and length can achieve more accurate placement,shorter operative time and less time of X-ray projections.

Objective:To investigate the clinical effect of using combined lumbar pelvis fixation device in the treatment of old vertical unstable fracture dislocation of posterior pelvic ring.Methods:Data of 7 patients with old vertical unstable fracture dislocation of posterior pelvic ring admitted and followed up from January 2017 to April 2020 were retrospectively analyzed, including 4 males and 3 females with an average age of 42.4 years old (range, 22-73 years old). There were 3 cases of traffic injury, 3 cases of falling injury and 1 case of tumble injury. According to Tile classification for pelvic fractures, there were 5 cases of type C1, 1 case of type C2 and 1 case of type C3. The average time from fracture to surgery was 5.4 weeks (range, 3-10 weeks). Among the 7 patients, 4 patients' posterior ring fractures were fixed by combined lumbar pelvic triangle fixation, and 3 patients' posterior ring fracture were fixed by combined lumbar pelvic fixation. 4 patients' anterior ring injury were not treated, 2 patients' anterior ring injury were treated by closed cannulated screw and internal fixation, and 1 patient's anterior ring injury was fixed by INFIX and cannulated screw. Every patient's operating time, intraoperative blood loss, length of incision and times of X-ray fluoroscopy were recorded. Pelvic X-ray and CT scan were taken postoperatively to observe the condition of reduction and screw position. Postoperative fracture reduction quality was assessed by Matta radiological criteria and Majeed criteria was used at the final follow-ups to evaluate the degree of functional recovery after pelvic fracture.Results:The average operating time of 7 patients was 143 min (range, 96-205 min); the intraoperative average blood loss was 579 ml (range, 300-1 650 ml); the average length of incisions was 12.9 cm (range, 9-15 cm) and the average time of X-ray fluoroscopy was 27 times (range, 15-52 times). Postoperative X-ray and CT scan showed that the displacements of the posterior rings were reset well and all the hollow screws were located accurately and firmly. Postoperative radiation quality was evaluated according to Matta radiological criteria, and there were 4 cases of excellent, 2 cases of good and 1 case of fair, with an excellent and good rate of 85.7% (6/7). Seven patients had good fracture union. The average followed up time for all 7 patients was 12 months (range, 6-16 months). At the last follow-up, imaging examination showed good reduction of the sacroiliac joint, and the reduction of anterior and posterior rings were not lost. The healing time was 14.2 weeks (range, 12-20 weeks). Majeed score: postoperative 4.90±6.64 points (range, 48-58 points), postoperative 3 months 71.40±7.32 points (range, 67-75 points), postoperative 6 months 84.90±8.14 points (range, 68-96 points), the difference was statistically significant ( F=0.614, P=0.004). Majeed score 6 months after operation showed that 5 cases were excellent, 1 case was good and 1 case was fair, and the excellent and good rate was 85.7% (6/7). Conclusion:Using combined lumbar pelvis fixation device in the treatment of old vertical unstable fracture dislocation of posterior pelvic ring has good reduction quality, high fixed strength and good postoperative effect.