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BACKGROUND: Locking pedicle screw system is commonly used in clinic, but it often suppresses spinal longitudinal growth of adolescent at growth phase. Thus, a pedicle screw system that can reduce even avoid the inhibition to spinal growth is needed. OBJECTIVE: To compare the biomechanical performance of sliding instrumentation of pedicle screw system and traditional locking pedicle screw system. DESIGN: Comparative observation. SETTING: Department of Orthopedics, Xinqiao Hospital of Third Military Medical University of Chinese PLA, and Department of Orthopedics, the 211 Hospital of Chinese PLA. MATERIALS: The experiment was performed at Department of Material Science, Harbin Institute of Technology on June 29th, 2007. Self-designed sliding pedicle screw system was made of Ti alloy by Wujin No. 3 Medical Instrument Factory Co., Ltd., Jiangsu Province. It consisted of sliding pedicle screw, orthopaedic rod and transversal coupling device. Twelve samples of fresh porcine spine were selected, and muscles attached on vertebral bodies of TrL5 were removed carefully but integrity of main ligament and precessus articularis posterior was retained. METHODS: The samples were randomly divided into sliding system group and locking system group with 6 samples in each group. Partial vertebral plate and surrounding ligaments of T12as well as bilateral facet joints between T11-12 and T12-L1 were removed to induce spinal destabilization, then sliding pedicle screw system and locking pedicle screw system were respectively fixed onto T10, T12, and L2 vertebral bodies of two groups. The samples then were fixed into fixture, and put onto INSTAON-4505 axial compressor. The strain gauge was connected with YJ-31 static electricity resistance strain gauge instrument human to simulate human spinal load, and the center of gravity was loaded to induce forward flexion, backward extension, lateral flexion and axial construction. Load of 100, 200, 300, 400 and 500 N was given gradually, and displacement of T12 was measured under different loads. MAIN OUTCOME MEASURES: ①Changns in principal stress and displacement under forward flexion, backward extension, lateral flexion and axial construction; ②Spinal fixation intensity and rigidity. RESULTS: No statistical difference was detected in main straining, displacement of apical vertebrae and intensity of fixation between sliding system group and locking system group under forward flexion, backward extension, lateral flexion and axial construction (P > 0.05). CONCLUSION: Sliding pedicle screw system has identical biomechanical stability as locking system. Furthermore, in sliding pedicle screw system, the screw and rod are coupled by sliding pattern, which extend along with spinal growth. It can be used to treat scoliosis at growth phase.
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BACKGROUND:Standing bending, supine bending, lateral pressing, pronation compression films and traction radiography are indeed effective to predict the correction outcome of surgeries by Harrington's method and Lugue's method,however, they are discontented for the correction of three-dimensional pedicle screw of vertebral arch.OBJECTIVE: To evaluate the role of preoperative X-ray films of gravity-suspending traction, supine bending and fulcrum bending in patients undergoing spinal three-dimensional correction and fusion for adolescent idiopathic scoliosis (AIS).DESIGN: Contrast observation.SETTING: Department of Orthopaedics, the 211 Hospital of Chinese PLA (Military Orthopaedics Center).PARTICIPANTS: From January 2003 to December 2005, 63 cases aged 10-21 years were recruited from Department of Orthopaedics in the 211 Hospital of Chinese PLA, including 18 males and 45 females. They were diagnosed as AIS by clinical examinations and X-ray film, with Cobb angle≥40°. Informed consents were obtained from all the subjects.METHODS: All of the 63 AIS cases with 79 structural curves were studied by preoperative X-ray films of standing,gravity-suspending traction, supine bending and fulcrum bending, which were compared with standing X-ray films one week postoperatively.MAIN OUTCOME MEASURES: Cobb angles of preoperative fulcrum bending film and postoperative standing film.RESULTS: All of the 63 cases were involved in the result analysis. There was no significant difference in the Cobb angle between preoperative fulcrum bending X-ray film and postoperative standing X-ray film (P ＞ 0.05). Gravity-suspending traction and supine bending films were significantly different from postoperative standing film (P ＜ 0.05).CONCLUSION: The fulcrum bending X-ray films are superior to gravity-suspending traction and supine bending films in predicting the postoperative correction of AIS patients.
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[Objective]To investigate the prevalence rate of adolescent scoliosis in Heilongjiang province. [Methods]A total of 17 525 students(aged 7 ~15 years old) from 28 primary and secondary schools were screened for scoliosis from April 2007 to May 2009.Physical examination,corrugated photography and X-ray were used for the screening,prevalence rate was calculated and correspondent treatment was given to patients.[Results]The result of first check-positive was 911(5.20%),with male 448(4.92%),female 463(5.44%).The second check-positive was 413(2.36),with male 181(2.00%),female 232(2.73%),387 in them received the third check.In the third check,335 patients were found the Cobb's angle ≥10?,with the prevalence rate of 1.91%(male 147,1.63%,female 188,2.21%).[Conclusion]Adolescent scoliosis can be early found,early diagnosed,prevented and treated by general survey.
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Idiopathic scoliosis is one of common adolescent malformations,it will harm patient's physical and mental health seriously.These years,surgical technique of adolescent idiopathic scoliosis has developed from rectification of single plane and segment to multi planes and segments,the effect of rectification improved much at the same time.This article reviews the developed course of the surgical technique of adolescent idiopathic scoliosis from two aspects:operating approach and operating method.It also recommends the extensively used operating styles at present.
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0.05).[Conclusion]There are the same correct effectiveness and the biomechanical stability in the treatment with the slidable pedicle screw system and universal pedicle screw system,meanwhile there is no effect in the adolescent growth.
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[Objective]To evaluate the role of three radiographic ways in patients undergoing spinal three-dimensional correction and fusion for adolescent idiopathic scoliosis.[Method]Sixty-three cases of adolescent idiopathic scoliosis(AIS)with 79 structural curves were studied.Preoperative X-ray of standing,gravity-suspendig traction,supine bending and fulcrum bending were compared with postoperative standing X-ray one week after surgery,Cobbs angle of all X-ray were measured and statistical significance was evaluated.[Result]In structural thoracic group and lumbar group the mean Cobbs angle were 40?and 21?in gravity-suspendig traction X-ray,41?and 23?in supine bending X-ray,35?and 19?in fulcrum bending X-ray,36?and 18?in postoperative standing X-ray respectively.In severe group and moderate group the mean Cobbs angle were 52?and 23?in gravity-suspendig traction X-ray,53?and 24?in supine bending X-ray,47?and 20?in fulcrum bending X-ray,44?and 19?in postoperative standing X-ray respectively.In rigid group and flexible group the mean Cobbs angle were 51?and 22?in gravity-suspendig traction X-ray,52?and 22?in supine bending X-ray,48?and 18?in fulcrum bending X-ray,45?and 17?in postoperative standing X-ray respectively.In anterior approach group and posterior approach group the mean Cobbs angle were 47?and 15?in gravity-suspendig traction X-ray,49?and 16?in supine bending X-ray,43?and 11?in fulcrum bending X-ray,42?and 10?in postoperative standing X-ray respectively.All above Cobbs angle were mean numerical value,the mean follow-up period was 1.5 years(range:1~3 years).[Conclusion]The fulcrum bending X-ray are more predicting of correctability of AIS patients than the gravity-suspendig traction and supine bending X-ray.It can provide reference for chosing anterior or posterior approach and chosing fusion levels.
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[Objective]To study the effect of improved universal pedicle screw systems which combined locking pedicle screws with sliding pedicle screws to correct the spinal deformities in growth period through posterior incision.[Method]From June 2000 to June 2006,209 spinal deformities in growth period were treated(106 males and 103 females),including 92 idiopathic scoliosis,72 congenital scoliosis,26 Scheuermanns diseases and 19 other kinds of spinal deformities.The age of patients ranged from 8 to 16 years(average 13.22 years).Locking pedicle screws were placed into pedicles of apical vertebra and the 3 to 5 adjacent vertebrae.Sliding pedicle screws were putted into pedicles of cephalic and caudal vertebrae.Double cross-links and rods were fixed and locked tightly.Sliding cross-links themselves could cannula prolonged to fit for the transverse development of vertebrae.[Result]Totally 209 cases with preoperative Cobbs angle 45 degree to 110 degree(average 68 degree)were instrumented with improved USS systems and 96 cases were followed up for 26～60 month.The length of spines were prolonged 4 cm to 15 cm with average 7 cm.With 26 months to 60 months follow-up,the whole spine growth was 230.4 cm with average 2.4 cm respectively.Rods broken were found in 6 patients and no other cmplication was detected.[Conclusion]Improved USS system which combined locking pedicle screws with sliding pedicle screws had the three dimensional power and intensity of traditional 3D instrumentations.Sliding pedicle screws and cross-links permitted longitudinal growth of the vertebrae and transverse development pedicles.
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[Objective]To design a new kind of instrumentation specially to correct scoliosis and kyphoscoliosis.[Method]Through posterior transpedicular and vertebrae,wedged osteotomy was continually performed until anterior substantia compacta of vertebrae.[Result]More than(1 200) patients with scoliosis or kyphoscoliosis were treated with WVOI.The highest ostentomied vertebrae was thoracic 9 and 4 levels were performed for 1 case(mean 2 levels).The average time of osteotomy on one vertebrae was 30 min with 100 ml blood loss.No spine and spinal root injury was detected during the operating procedure.[Conclusion]Osteotomy with WVOI reduced operating time,blood loss,keep spine and spinal root safer during the operating procedure.It also made osteotomical plate fit well and prompted quick ossification.WVOI is an efficient instrumentation to correct kyphosis and kyphoscoliosis.
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@#ObjectiveTo investigate the effect of surgery treatment for syringomyelia associated with spinal cord type cervical spondylopathy.MethodsExpansive open-door laminectomy and spinal cavity-subarachnoid drainage were performed in 11 cases.ResultsThe extremity function of 11 cases were all recoverd to varied extent in the following 1-5 years(average follow-up:30 months).ConclusionsExpansive open-door laminectomy and spinal cavity-subarachnoid drainage is an effective method for syringomyelia associated with spinal cord type cervical spondylopathy.