[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.

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.

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.

OBJECTIVETo establish a mechanical simulation model for studying the relationship between the characteristic frequency and feature location of the basilar membrane of the cochlea.

METHODSMacro-mechanical methods were used to simplify the details of the model. With simulation tools, the basilar membrane vibration frequency characteristics were analyzed based on the box model.

RESULTSThe basilar membrane had obvious frequency-selective properties, and the basilar membrane from the stapes was sensitive to high frequencies while the farther membrane was sensitive to low frequencies.

CONCLUSIONThe frequency characteristics of the basilar membrane of the cochlea is mainly a result of the longitudinal variations of the geometric dimensions and material properties and is not related with other structures within the cochlea corti.

Basilar Membrane ; physiology ; Cochlea ; physiology ; Computer Simulation ; Mechanics ; Models, Biological ; Vibration