Objective: To summarize the diagnosis and measurement methods of bone defect in anterior shoulder instability (glenoid bone defect and Hill-Sachs lesion). Methods: The related literature on the diagnosis and measurement of the bone defect in anterior shoulder instability was reviewed and summarized. Results: The commonly used techniques for the diagnosis of anterior glenoid bone defect and Hill-Sachs lesion of humeral head include X-ray, CT, MRI, arthroscopy, arthrography. The methods for measuring the degree of anterior glenoid bone defect include Griffith method, glenoid index method, Pico method, and best-fit circle method. The indexes for measuring the Hill-Sachs lesion include the length, width, depth, and volume. X-ray is mainly used for primary screening. Best-fit circle method on three-dimensional (3D) CT reconstruction is commonly used to measure the glenoid bone defect currently. Glenoid track theory on 3D CT reconstruction is popular in recent years. Reliability of measuring the glenoid bone defect and Hill-Sachs lesion with MRI and arthroscopy is still debatable. Arthrography is more and more used in the diagnosis of shoulder joint instability of bone defect and concomitant soft tissue injury. Conclusion: How to improve the accuracy of evaluating glenoid bone defect and Hill-Sachs lesion before surgery still need further study.

Objective To investigate the changing characteristics of the fractional anisotropy (FA) in cerebral peduncles and its relation with motor evoked potential (MEP) after acute cerebral infarction and to clear the clinical sigiificance of the low limit value of the FA in cerebral peduncles. Methods The low limit value of the FA in normal cerebral peduncles was determined based on mean - 1. 64 standard deviation. The patients with acute cerebral infarction (n = 58) were divided into MEP positive group and MEP negative group according to the absence and presence of MEP, in which the patients in the MEP positive group were redivided into the FA in cerebral peduncles ＜ the low limit value and≥ the low limit value groups according to the FA in cerebral peduncles on the affected sides. Results The low limit value of the FA in normal cerebral peduncles was 0. 36. There was significant difference in the FA in cerebral peduncles on the affected sides between the MEP negtive and MEP positive groups. The MEP negative group was the lowest (P=0. 000). The FA in cerebral peduncles on the affected sides in the positive group was significantly lower than that on the unaffected sides (P=0. 000), and the latency on the affected sides was longer than that on the normal sides (P=0. 000). The FA in cerebral peduncles on the affected sides was negatively correlated with the MEP latency (r=-0.332,P=0. 042). The MEP latency in the FA＜the low limit value group was significantly longer than that in the FA ≥ low limit value group (P=0. 002). There were no significant differences in the FA in cerebral peduncles on the normal sides and the MEP latency among an groups. The detection rate of the FA in cerebral peduncle＜0. 36 on the affected sides was the highest (50%). Conclusions In the evaluation of the prognosis of the patients, the changes of the FA in cerebral peduncles on the affected sides in patients with acute cerebral infarction had correlation,consistency, and complementarity with MEP.The detection rate of the low limit value of the FA in normal cerebral peduncles was the highest in the MEP negative patients. When the FA in cerebral peduncles was＜0.36 on the affected sides, particularly when MET was negative, it might predict that the prognosis was poor.

Objective To explore a safe and effective posterior surgical operation for correction of the horacolumbar kyphotic deformity. Methods The study involved 16 patients with thoracolumbar kyphotic deformity treated with the modified posterior transpedicular-intervertebral disc wedge resection osteotomy and screws-rods internal fixation apparatus.There were 11 males and 5 females at an average age of 26.5 years(13-53 years).The kyphosis deformity was caused by ankylosing spondylit in four patients,old lumbothoracic fracture in nine,vertebral dysplasia in two and vertebral body in one.The preoperative kyphosis Cobb angle was 58.1(45°-85°),with the kyphosis deformity at T10 in two patients,at Thin two,at T12in six,at L1 in three and at L2 in three.The main clinical manifestations were different degrees of lower back pain and progressive aggravation of the deformity,influencing the work and living.The course of disease was 8.5 years(4-17 years).All patients underwent pesteriortotal vertebral osteotomy on the apex vertebra,trails-pedicular fixation combined with correction and fusion,after which the patients stayed in bed for four weeks and received orthosis fixation for three months after operation. Resuits The operation lasted for average 190 minutes(125-240 minutes),with average blood loss of 750 ml(450-1 900 m1).All patients were with single segment cut bone,with no spinal cord injury,neurological injury or hardware failure.The post-operative vertical plane facial deformity was corrected for average 55(44°-76°),wit average correction rate of 83%.The follow-up for 10-24 months showed firm internal fixation on the X-ray film and good fusion ofthe vertebral column,with no pseudoarticulation formation,loosening internal fixation or loss of correction.All the patients obtained obvious improvement in appearance of the deformity,with disappearance of the lower back pain and improvement of the quality of life. Conclusion One stage posterior transpedicular-interverte-bral disc wedge resection osteotomy is all effect and safe surgical technique for correction of horacolumbar kyphotic deformity.

Objective To compare the clinical curative effect of pedicle screw reduction and fix-ation via or not the injured vertebra in treatment of thoracolumbar fractures. Methods A retrospective study was performed on 27 patients with single thoracolumbar fractures admitted from March 2006 to Feb-ruary 2008. There were 12 patients treated with pedicle screw fixation (Group A) and 15 with traditional two-level fixation (Group B). Group A involved 11 males and 5 females, aged average 43 years (25-56 years); Group B included 10 males and 5 females, aged from 23 to 61 years (mean 42 years). All pa-tients had fresh fractures with intact pedicles on either unilateral or bilateral sides. With body position re-duction under anesthesia, the patients in Group B were treated with posterior routine distraction and lordo-sis restoration, while those in Group A were treated with the methods used in Group B as well as pedicle screw reduction and fixation. The kyphosis (Cobb angle) and recovery of injured vertebral height were observed. Results The mean follow-up period was 9 months (6-22 months). After operation, the op-timal Cobb angle and anterior column restoration were achieved through the ventral reduction from the in-jured vertebral body. The degree in anterior movement of injured vertebrae pre- and post-operatively was (0.089±0.036)° in Group A and (0.023±0.048)° in Group B, with statistical difference (P < 0.01). Cobb angle was (9.88±7.69)° in Group A and (5.19±3.24)° in Group B (P < 0.05). Changes of distance between the anterior- upper edge of the cephalad vertebrae to the anterior - lower edge of the caudal vertebral body was (39.3±5.2) % in Group A and (20.6±6.5)% in Group B (P < 0.05). Over distraction of the contiguous discs was also avoided efficiently. Conclusions Selective pedicle screw fixation into the injured vertebrae can help correct the kyphosis and maintain the reduction and en-hance the stiffness of the posterior short-segment instrumentation in single thoracolumbar fractures.

Object To discuss the surgical techniques and the clinical outcomes of the bilateral microendoscopic decompression surgery for lumbar spinal canal and lateral recess stenosis through unilateral approach. Methods 18-ram-diameter microendoscopic tubular retractor was placed with fluoroscopic gnidance, bilateral microendoscopic decompression surgery for lumbar spinal stenosis through unilateral approach were managed by adjusting the angle of tubular retractor. During the procedure, supra-interspinal ligament and contralateral bony lamina were well preserved. Results In the group of single-level microendoscopicdecompression, the mean operation time was 94 min and the mean blood loss was 65 ml. In the group of twolevel microendoscopic decompression, the mean operation time was 135 rain and the mean blood loss was 90 ml. The mean bed rest time was 6.5 days. After operation, the average back pain VAS score decreased from 6.5 to 3.1, the average leg pain VAS score decreased from 7.2 to 2.2, the average Oswestry Disability Index (ODI) decreased from 46.8 to 24.6, which had shown significant statistical difference before and after surgery (P ＜ 0.05). According to Nakai criteria, the excellent and good rate was 84%. Conclusion Bilateral microendoscopic decompression of lumbar canal through unilateral approach under METRx system offers a save, effective and minimal invasive option for lumbar spinal stenosis.

Based on the analysis of the current status and limited factors of MISS at home and aboard,this paper discussed on the importance of MISS training base construction and explored the construction from the aspects of infrastructure constructing,teaching staff training,teaching materials compiling and teaching practice(teaching forms,contents and evaluation)researching.

Objective To evaluate surgical techniques and clinical results of percutaneous transforam-inal endoscopic discectomy in the treatment of far lateral lumbar disc herniation. Methods Thirty-sev-en patients (24 males and 13 females) with far-lateral lumbar disc herniation were treated by percutane-ous transforaminal endoscopic discectomy from September 2005 to October 2008. The mean age of the pa-tients was 40.6 years. There were 19 patients (51.4%) with foraminal lumbar disc herniation, 11 (29.7%) with extraforaminal lumbar disc herniation and 7 (18.9%) with mixed lumbar disc herniation. The mean operation time, stay-in-bed time, postoperative hospital stay were 70 minutes, 9 hours and 5.0 days respectively. The mean operation costed mean 9 800 ￥ RMB. Results All the patients were fol-lowed up for an average period of 11.5 months. The efficacy of percutaneous transforaminal endoscopic discectomy was determined by Visual Analog Score (VAS), Oswestry Disability Index (ODI) and Nakai criteria. The mean value of VAS was significantly decreased from preoperative 8.3±2.3 to 3.1±1.6 at postoperative month 3, and to 2.9±1.9 at postoperative month 6 (P < 0.01). The mean value of ODI was significantly decreased from preoperative 64.5±23 to 23.6±12.0 at postoperative month 3, and to 12.9±7.0 at postoperative month 6 (P < 0.01). According to the Nakai criteria, the outcome of the op-eration was excellent in 19 patients (51%), good in 13 (35%), fair in 2 (5%) and poor in 3 (8%), with overall excellence rate of 87%. Conclusions Transforaminal percutaneous endoscopic discecto-my is safe and efficacious in the treatment of far lateral lumbar disc herniations, and proper selection of patients is the key factor to ensure the outcome of the operation.

Sodium hyaluronate is one of the natural components of articular cartilage and synovial fluid,which plays important roles in maintaining the structure and physiological functions of joints.Abnormal change of the content and physicochemical properties of sodium hyaluronate in the joints is one of the common pathological causes of osteoarthritis.Supplementation of exogenous sodium hyaluronate,which has similar physical and chemical properties as those in normal joints,has been considered as an effective strategy for clinical treatment of osteoarthritis.However,the benefits of intra-articular injection of sodium hyaluronate are still under debates.Moreover,different recommendations for clinical use were developed in several clinical guidelines.Several guidelines suggested that molecular weight of sodium hyaluronate was an important factor influencing the clinical benefits in osteoarthritis.Diverse products of sodium hyaluronate present different physicochemical and biological characteristics,which may lead to differences in clinical efficacy and safety.High-molecular-weight sodium hyaluronate,with highly modified and cross-linked sugar chains,potentially differ from those with low molecular weight in physicochemical properties,rheological characteristics,and physiological activities.In general,high-molecular-weight sodium hyaluronate have higher viscosity and elasticity.The exogenous hyaluronate,of which the molecular weight is similar to those in normal joints,probably have the similar rheological characteristics.A large number of clinical studies demonstrated that sodium hyaluronate products with high-molecular weight significantly relieved joint pain and improved joint functions in patients with osteoarthritis.In contrast,the clinical efficacy of the low-molecular-weight hyaluronate is still controversial,because several studies could not establish the superiority in osteoarthritis when comparing with the placebo.Studies on molecular mechanisms revealed that some physiological functions of sodium hyaluronate were molecular-weight dependent.High-molecular-weight sodium hyaluronate may have more pronounced impacts on the regulation of inflammation and maintaining the homeostasis of extracellular matrix.This review focused on the effects of sodium hyaluronate with different molecular weight in treating osteoarthritis.Evidence based on clinical studies related to the molecular-weight differences of sodium hyaluronate were presented.Furthermore,the optimal use of various products of sodium hyaluronate with different molecular weight was discussed.

ObjectiveTo retrospectively analyze the treatment of odontoid fractures using percutaneous and open anterior screw fixation,and compare the clinical and radiographic results of the two techniques.MethodsFrom March 2003 to May 2010,115 patients with odontoid fracture were treated with anterior screw fixation,and all patients were followed up.The mean age of the patients was 43.5 years (range,16-71).Forty-seven patients who underwent percutaneous anterior screw fixation were set as the percutaneous fixation group,including 42 cases of type Ⅱ odontoid fracture and 5 of rostral type Ⅲ fracture.Sixtyeight patients who received open anterior screw fixation were set as the open fixation group,composing of 61cases of type Ⅱ odontoid fracture and 7 of rostral type Ⅲ fracture.We compared the operative time,intraoperative blood loss,X-ray exposure time,fracture union and complications between the two groups.Results The average follow-up duration was 37.6 months with a range of 12-70 months.The gender,age,classification of odontoid fractures,time after the injuries and concomitant spinal injuries showed a similar pattern in both groups.The operating time and intra-operative blood loss in percutaneous fixation group were (40.3±9.5)min and (5.6±4.1) ml respectively,and in open fixation group were (62.9±15.3) min and (47.1±28.6) ml respectively,both of them were significantly superior in percutaneous fixation group than in open fixation group (P＜0.05).There was no statistical difference in radiation exposure time,fracture union and incidence of complication between the two groups.ConclusionComparing with open screw fixation,percutaneous anterior screw fixation is a safe and reliable procedure for treatment of type Ⅱ and rostral type Ⅲ odontoid fractures with potential advantages.

Objeetive To evaluate the performance characteristics of the second trimester double test for the detection of fetal Down's syndrome(DS)in women of advanced maternal age(AMA).Methods We undertook a prospective nation-wide multi-centered study and chose alpha-fetoprotein(AFP))and free β-subunit of human chorionic gonadotrophin(free β-hCG)as the serum markers.Between May 2004 and September 2006,12 centers participated in the collection and analysis of maternal serum AFP and free β-hCG.Patients with an iuereaged risk of DS(≥1/270)wero offered generic sunniocentesis.Follow up of the outcome of all pregnancies was obtained.Patients were divided into two groups,the AMA group and the non-AMA group and the screening efficiency Was evaluated in beth groups.Results A total of 66 132 singleton pregnancies were included in the study.and there were 36 10(5.46%)AMA women.The median maternal age of AMA women was 36.8years(35-47 years).At a cut-off of 1/270,in the AMA group,the number of positive cases screened was 727 and 22 cases of fetal DS were detected:the number of negative cases screened was 2883,and no fetal DS was found.In the non-AMA group,the number of positive cases screened was 4743 and 69 cases of fetal DS were detected:the number of negative cases screened was 57 779,and 6 cases of fetal DS were diagnosed postnatally.In AMA group,the detection rate(DR),false positive rate(FPR)and odds of being affected given a positive result(OAPR)were 100%,19.7%and 3.0%respectively.In the non-AMA group,the DR,FPR and OAPR were 92.0%.7.5%and 1.5%respectively.Conclusion The double-marker test using AFP and free β-hCG is an effective screen strategy for second-trimester detection of Down syndrome in AMA women.