Objective To establish a three-dimensional finite element model and make mechanical analysis of "V"-type atlantoaxial reduction and internal fixation. Methods According to "V"-type atlantoaxial and internal fixation,based on screw-type Ⅱ design parameters,and using Pro/E 2001 and MSC.Patran 2005 software,we set up a finite element model and calculated the region containing the node scope of the force as the sites binding and 100N mechanics adding. Results The model looked realistic,geometric similarity.The deformation stress field mainly concentrated in the reset device V-tip arm bending and stability.The strength of its maximum stress was 4.78MPa,and the scope had 2794 nodes.V-type wing of the acute angle point of convergence of the premises to bear the stress intensity followed.It was 0.31MPa,and the scope had 1953 nodes.V-type wing by the end of edge was the smallest for the 1.22?10-3MPa,and there was the scope of 1730 nodes. Ⅱ-shaped fixed nail stress concentrated at the central parts of tooth and the art on both sides of teeth,with maximum stress intensity of 1.68?10-2MPa,and there was the scope of 1146 nodes. Conclusion The reduction and fixation devices to load at the time of recovery deformation forces and mechanical characteristics adapted to Ni-Ti shape memory alloy material functions and super-elasticity completely,which meets the clinical needs.

BACKGROUND:Anterior cervical discectomy and intervertebral disc replacement have been extensively used in treatment of cervical degenerative disease. Its short-term therapeutic effects are encouraging, but it lacks of long-term and comprehensive evaluation.
OBJECTIVE:To observe the folow-up results of a group of cases of anterior cervical discectomy and Mobi-C intervertebral disc replacement for more than 5 years.
METHODS:A total of 25 cases of cervical spondylosis were treated in the 309 Hospital of Chinese PLA from January to September 2009. 19 of them were folowed up. Al patients received anterior cervical discectomy and Mobi-C intervertebral disc replacement. Twenty-three Mobi-C intervertebral disc prostheses were implanted. The range of motion was measured using lateral X-ray films during extension and flexion. Ectopic ossification was assessed by McAfee method. According to the cervical vertebra MRI images, the degeneration of adjacent segments was determined using Pearce classification. NDI score was used to evaluate the function of cervical spine. Pain improvement was evaluated using visual analogue scale score.
RESULTS AND CONCLUSION: A total of 19 patients were folowed up for 59-65 months, averagely 62 months. No significant difference in range of motion was detected before surgery and during final folow-up (P > 0.05). Ectopic ossification in two cases and the degeneration of adjacent segments in one case were found during final folow-up. No prosthesis loosening or displacement appeared. Visual analogue scale score and NDI score were significantly lower during final folow-up compared with that before surgery (P < 0.05). These results indicate that under the premise of reasonable choice of indications, the therapeutic effect of Mobi-C intervertebral disc replacement for degenerative cervical spondylosis was satisfactory in five-year folow-up. The range of motion was good, and the incidences of ectopic ossification and the degeneration of adjacent segments were low.

Objective To observe the clinical effects of anterior plates with titanium mesh and bone graft (auto and allo) in treatment of cervical spine fractures. Methods 42 cases of fractures of cervical spine treated with anterior plates with titanium mesh. Results The bone graft (auto and allo) were followed up for 4 to 28 months (mean 17 months). The preoperative and postoperative nerve functions were evaluated according to JOA criteria. The cervical curvatures, sink or shift of the mesh and bone fusion were evaluated by X rays. There were no significant complications during perioperative periods. The functions of spinal cord were improved, the cervical curvatures were restored, and no sinking or shifting of the mesh was observed. There was also no loosening of plate or screw. The fusion began 3.5 months postoperatively, and a good fusion could be observed 1 year postoperatively. Conclusion By application of anterior plates with titanium mesh and bone graft (auto and allo) in treatment of cervical spine fractures, the cervical curvature and stability can be restored, the iliac lesion and long operation duration caused by the harvest from ilium can be avoided, better fusion and quicker recovery can be obtained.

Objective To evaluate the result of anterolateral interbody fusion combined with transpedicle fixation for patients with kyphosis due to tuberculosis of the thoracic spine. Methods There were totally 17 patients, 11 male and 6 female in this study. The average age was 36.4 years, ranging from 23 to 56 years old. All tuberculous lesions were located in low thoracic spine, two vertebral bodies were involved in 9 patients and three vertebral bodies involved in 8 patients. The average kyphosis angle was 25 degrees, ranging from 15 to 34 degrees. Mild neurological function deficiency (Frankel Grade C or D) were present in 5 patients. All patients were treated with one stage posterior transpedicle fixation and anterolateral interbody fusion combined with 9 month antituberculous medication. Results All patients were followed up for 2 to 4 years postoperatively. All incisions were healed up primarily. Interbody fusion was achieved in all patients from 4 to 6 months after operation. All patients were cured and there was no recurrence within follow up period. The average kyphosic angle was 7 degree postoperatively, and the average correction of kyphosis angle was 18 degree, which was maintained well within follow up period. Patients with neurological function deficiency achieved complete recovery one year after operation. Conclusion Anterolateral interbody fusion combined with transpedicle fixation provides rigid fixation and good stability for early fusion and facilitates tuberculous kyphosis correction. This one stage procedure is effective in decreasing duration of antituberculous medication and increasing curing rate of spinal tuberculosis.

Objective To introduce the operative procedure of prosthetic disc nucleus(PDN)re-placement and investigate its clinical effectiveness in the treatment of lumbar disc herniation.Methods Nine cases of lumbar disc herniation were treated with PDN replacement from March2002to April2002.There were6males and3females,the average age of the patients was33.4years ranging from22to48years.The interval between the onset of the symptoms and the diagnosis was averagely18.4months,ranging from8months to3.6years.All of the patients were evaluated by anteroposterior and lateral radiography,computer-ized tomography and,if necessary,magnetic resonance imaging.The low back pain was predomi nant in two patients,the low back pain associated with radicular leg pain in6patients.The height of disc space became narrowed in varying grade.The operated level was at L 4-5 in6patients,L 5 S 1 in3patients.The standard pos-terior approach was used in8patients;the anterior lateral retroperitoneal approach was adopted in1patient.8cases were implanted with a single PDN,and1case with a couple of PDNs.Results All patients were followed up12to13months(average12.3months).The estimated intraoperative blood loss ranged from50to150ml (mean120ml ),and the total operation time ranged from45to120min(mean60min).The patients wore a brace for the first6weeks.Based on Oswestry low back pain and dis ability scores,the clinical successful rate was88.9%.The average percentage of the postoperative to preoperative disc height was128%.The slight displacement of PDN was observed in2patients,however there was no change of lumbar spinal mo bility.1patient had a bad recovery of back and leg pain.Conclusion PDN re placement can improve clinic symptoms,increase disc height and restore the normal lumbar motion as well.Its clinical effectiveness is excellent in short-term observation.

From July 1997 to March 2000, internal fixation of posterior transpedicular screw system and posterolateral autograft bone graft fusion procedures were used in 25 patients suffering from Pott's paraplegia in our department. 17 of them were involved in a longitudinal study and followed up for a mean of 2(1 5～4)years postoperatively. The beginning of neurologic recovery was during the first 2 to 3 weeks postoperatively in 16 patients. 9 were completely recovered,7 were partly recovered 6 months postoperatively. At final follow up, 2 of the 7 patients were completely recovered, 5 had significant improvement of one grade(2 patients) or two (3 patients) according to ASIA Grades. It is concluded that internal fixation of posterior transpedicular screw system and posterolateral autograft bone graft fusion procedures were found to be helpful in strengthening the stability of the spine in spinal tuberculosis, providing successfu recovery of paraplegia and preventing the recurrence of paraplegia.

Objective To investigate the clinical viability of pre-eclampsia by measuring the level of ?-HCG in blood,blood calcium,hematocrit(HCT)and the mean arterial blood pressure(mABP).The preventive value of calcium supplement was also evaluated. Methods 356 volunteers'(16th～20th gestational weeks)were measured ?-HCG in blood,blood calcium,HCT,meanwhile mABP from the same patients.If blood ?-HCG≥50 632 IU/L,blood calcium≤2.18 mmol/L,HCT≥0.35 and mABP≥85 mm Hg(1 mm Hg=0.133 kPa),a positive conclusion was made.Women with positive results were randomly divided into test group and control group. Results 71 cases turned out to be positive in this serial test.The positive predictive value was 81.82%,negative predictive value was(97.30%),the sensitivity and specificity were 84.38% and 96.77% respectively.In the study group,the incidence of pre-eclampsia was significantly decreased as compared with the control group(P

From January 2005 to January 2008, 23 cases of fractures and dislocations of cervical spine treated with anterior decompression, reconstruction of bone graft with titanium mesh, and titanium locking plates fixation in Department of Orthopaedics, the 309 Hospital of Chinese PLA were retrospectively analyzed, including 16 males and 7 females, aged 41.9 years (ranging 25 ?65 years). The clinical effect and application value of this treatment was evaluated; the conditions at preoperative, immediate postoperative and follow-up were evaluated by JOA grade, and these radiographs were taken. Lordosis (kyphosis) of the fusion segment with Cobb's angle, and lordosis (kyphosis) of cervical spine with D value were measured to evaluate effect of reconstruction and cervical spine physiological curve. All cases were followed-up for 20.5 months (ranging 1-3 years). Clinical stability was reached in all cases during the follow-up. There were significant differences between preoperative and immediate postoperative, between preoperative and follow-up groups in terms of JOA grade, Cobb's angle and D value (P < 0.05). The JOA grade of immediate postoperative was improved compared with that during follow-up (P < 0.05). The mean improvement rate was 63% at 1 year of follow up. A good curative effect was obtained by using anterior locking plate with titanium mesh systems in treatment of cervical fractures and dislocations and a good effect of restoring and maintaining the lordosis of cervical spine can be also obtained.

Objective To study the relationship between breast symptom, characteristic of ultrasound image and sex hormone level in women with different menstruation status.Methods 50 women with normal men-strual cycle, 129 women in menopause transition and 318 menopausal women were recruited.Breast ultrasound were performed.Breast section thickness, ductal width, breast structure and blood flow were measured.Serum estradiol( E2 ) and progesterone( P) level were measured by enzyme immunoassay on the day when ultrasound was performed.Onset and persistent days of breast pain were recorded.Results ①32(60.4%)women with normal menstrual cycle and 74(57.4%)women in menopause transition women experienced cyclic mastalgia.The aver-age serum E2 level and serum progesterone level were higher in women with cyclic breast pain than in women with-out breast pain.12.5%of menopausal women had breast pain.There was no significant difference of average ser-um E2 level between women with cyclic breast pain and women without breast pain②Breast section thickness was (14.4 ±4.3)mm,(13.0 ±3.7)mm and(10.6 ±3.2)mm, and ductal width was(0.62 ±0.18)mm,(0.88 ± 0.39)mm and(0.90 ±0.47)mm in normal menstrual group, menopause transition group and menopausal group, respectively.The difference had statistical significance.③26 women ( 49.1%) in normal menstrual group had breast structure changes, while 42 cases ( 32.6%) and 60 cases ( 18.9%) in menopause transition group and menopausal group had breast structure changes.Conclusions Most women in normal menstruation and meno-pause transition group experience mastalgia.About 1/3 breast structure change in women of normal menstruation are inversible.About 1/2 breast structure change in menopause transition and menopausal group are similar to those with normal menstruation.

All twenty seven patients suffered from Ⅱ grade spondilolisthesis were treated by posterior decompression, fixation with RF system and interbody fusion with TFC. One to three yearsafter operation, pain relief rate was 95%, lumbar fusion ratewas 95%,slip correction was 93.8%, and disc space was increased by 34%. It is concluded that this kind of operation can achieve satisfactory clinical results.