AIM: To analyze biomechanical characteristics after artificial intervertebral disc implantation. METHODS: A computer-based online search of Pubmed database and Chinese Journal Full-text Database was undertaken to identify articles about artificial lumbar intervertebral disc application. In addition, the articles published in authoritative journal in recent 5 years were selected firstly. Repetitive studies or Meta analysis were excluded. The references of each article were looked up, and summarized. RESULTS: ①Artificial intervertebral disc can rebuild and retain normal physiologic activities of spine. How to design the rotation center of each lumbar moving segment to make it move with flexion, extension, lateral flexion and rotation, and axial rotation along with lumbar lateral flexion. ②Although the material and design are different, current used several prostheses have common movement mechanism, i.e. ball-joint, similar to Fernst joint metal ball, which is not found in normal intervertebral disc. ③With the development of intervertebral disc replacement, it has become an novel technique to treat intervertebral lumbodorsal pain. Although many prosthesis is under exploration, some reports and short-follow up results have suggested intervertebral disc replacement retains spine activity, significantly relieves pain in short period of time, and improves life of quality. But the long-term follow up is little. CONCLUSION: It is documented that artificial intervertebral disc can remain enough height of intervertebral space and lumbar motion function. The short-term clinical outcomes are fair, but long-term effect still needs further clinical experiments and long-term follow up.

Objective To evaluate rhBMP-2/20%β-TCP/PDLLA complex biological properties.Methods Preparation of casting salting was carried out using three-dimensional porous 20% rhBMP-2/β-TCP/PDLLA. 24 4-month-old healthy male New Zealand rabbits were randomly divided into A,B groups of 12,according to the method described in Boden production L4,5 intertransverse process fusion model. A group was embedding rhBMP-2/20%β-TCP/PDLLA complex,and B group was implanted autogenous iliac bone block. Animals were killed according to postoperative time(3 weeks,6 weeks, 12 weeks) ,for gross observation, X-ray observation of the formation of new bone, artificial bone degradation, and early histological manifestations. Results Composite artificial bone and autologous iliac bone graft were able to achieve good spinal fusion,artificial bone graft where there is no inflammatory response,but also in new bone formation,while reshaping the gradual degradation of carrier material. Conclusions 20%β-TCP/PDLLA showed good biocompatibility. Its structure and micro-environment created by its degradation were conducive to play a role for the rhBMP-2. β-TCP/PDLLA had strong activity in inducing bone and good bone fusion ability,and it was a promising bone graft substitutes, which fusion power was stronger than that in autologous iliac bone graft.

BACKGROUND:Cuttlebone/racemic polylactic acid composite artificial bone has been prepared in the previous studies to improve the incomplete degradation of cuttlebone. OBJECTIVE:To observe the degradation and biocompatibility of cuttlebone/racemic polylactic acid composite artificial bone in animals. METHODS:Thirty healthy New Zealand white rabbits were randomly divided into four groups. Models of right radial defects were prepared in rabbits, and model rabbits were subjected to implantation of cuttlebone/racemic polylactic acid composite artificial bone into the defects and muscular sac between the radial lateralis muscle and rectus (experimental group), implantation of cuttlebone into the defects and muscular sac between the radial lateralis muscle and rectus (control group 1), implantation of racemic polylactic acid into the defects and muscular sac between the radial lateralis muscle and rectus (control group 2), or no treatment (blank control group), respectively. At 2, 4, 8 weeks after operation, X-ray and histological examinations were performed in the four groups. RESULTS AND CONCLUSION:(1) Compared with the other three groups, the bone mineral density of the experimental group was significantly higher at 4 and 8 weeks after material implantation into the defects (P < 0.05), and moreover, the bone mineral apposition rate of the experimental group was significantly higher at different time after operation (P< 0.05). At 8 weeks after operation, the bone tissues in the experimental group grew from the both ends to the center to form multiple bone island-like structures, with less residual materials, and the marrow cavity and implanting material were in a traffic manner; in the control group 1, there were many residual materials, and no intercommunication was found between the marrow cavity and implant material. (2) At 2 weeks after material implantation into the muscle capsule, there were more inflammatory cels, but the inflammation relieved at 4 weeks and disappeared basicaly at 8 weeks, and the material was degraded partialy. These findings indicate that the cuttlebone/racemic polylactic acid composite artificial bone is a kind of good bone substitute material that has good biocompatibility and degradability.

Objective To study the effect of cervical disc replacement in the treatment of cervical spondylotic myelopathy(CSM).Methods 21 patients with CSM(17 cases of spondylotic myelopathy,2 cases of radiculopathy and 2 cases of acute soft disc herniation)were treated by anterior decompression and replaced by the Bryan cervical disc prosthesis. Results All cases were: followed for 4～12 months, average 8 months. The pre-operative JOA score was 8.5 and post-operative score was 15.5 on average. There were no prosthesis, curve was good. Replaced segment achieved stability and restored partial of normal ROM. There was no subsidence of implant and no worsening of pre-operative symptoms, post-operative 21 cases remained flexion/extension movement at replaced segments at latest follow up. There was no neck stiffness and restriction of movement complained by the patients. Conclusion The Bryan cervical disc replacement for the treatment of CSM has offered an excellent early clinical outcome.

BACKGROUND:Due to the higher modulus of elasticity, titanium cages are prone to have the folowing shortcomings: adjacent vertebral sinking and delayed fusion resulting from stress shielding; therefore, in recent years, it has been gradualy replaced by polyetheretherketone cages. OBJECTIVE:To compare the clinical and radiographic outcomes of patients undergoing posterior lumbar interbody fusion with pedicle screw fixation in which either a polyetheretherketone cage or a titanium cage was implanted. METHODS: The pre- and postoperative data of 104 patients who underwent single-level posterior lumbar interbody fusion were colected and analyzed, including 57 males and 47 females, aged (41.2±10.5) years. The 58 of 104 patients received the titanium cage and the remaining 52 patients received the polyetheretherketone cage. Visual analog scale scores and Japanese Orthopaedic Association Scores of the lumbar and lower limbs were recorded at 24 hours of postoperative folow-up; CT scan was used to detect bone fusion and cage subsidence. RESULTS AND CONCLUSION:After 12 and 24 months of folow-up, the visual analog scale scores and Japanese Orthopaedic Association Scores of the lumbar and lower limbs were al improved in the two groups compared with the previous (P < 0.05), but there was no difference between the two groups. At 12 and 24 months of folow-up, the fusion rates were 94% and 100% in the titanium cage group as wel as 74% and 84% in the polyetheretherketone cage group, respectively, and a significant difference was found between the two groups (P=0.012 andP=0.016). At 24 months of folow-up, the subsidence rate was 36% in the titanium cage group and 30% in the polyetheretherketone cage group, and there was no difference between the two groups. These findings indicate that the superiority of polyetheretherketone cages over titanium cages has not been demonstrated.

BACKGROUND:Most of lumbar degenerative diseases, such as lumbar instability, lumbar disc herniation and discogenic lumbago, need lumbar spinal fusion for the spine stability, but the choice of internal fixation approaches is controversial.
OBJECTIVE:To compare the effectiveness between lateral lumbar interbody fusion with single cage and single cage combined with unilateral pedicle screw fixation for the 4th and 5th single-level lumbar degenerative disease.
METHODS:The clinical data of patients with single-level lumbar degenerative diseases (L4 and L5) undergoing lateral lumbar interbody fusion with single cage in 30 cases (experimental group) and single cage combined with unilateral pedicle screw fixation in 45 cases (control group) were analyzed retrospectively, and the curative effects were compared between the two groups.
RESULTS AND CONCLUSION:Al patients in the two groups were fol owed up for 13 months on average (ranged from 10 to 37 months). The incisions in the two groups were stage I healing. One case in the experimental group occurred cage displacement, but no obvious syndromes were detected. No significant difference in the effective rate after operation, hospital stay, and volume of drainage was detected (P>0.05). The operative time and bleeding volume in experimental group were better than those in the control group (P<0.05). ODI and JOA scores were significantly improved after treatment when compared with preoperative ones in the two groups (P<0.05), but no significant difference was visible between the two groups (P>0.05). The effectiveness of lateral lumbar interbody fusion with single cage and single cage combined with unilateral pedicle screw fixation for single-level degenerative lumbar diseases was similar. However, the former has the advantages of less invasion and quick recovery.

BACKGROUND:At present, it remains unclear whether delayed functional exercises after arthroscopic rotator cuff repairs could elevate the healing rate of tendon. The opportunity of functional exercises after rotator cuff repairs is stil controversial, and there is no relevant system evaluation.
OBJECTIVE:To systematical y evaluate the differences in curative effects of early and delayed functional exercises after arthroscopic rotator cuff repairs.
METHODS:We searched the Pubmed, EMBASE, Cochrane Central Register of Control ed Clinical Trials, Chinese Biomedical Literature Database, Wanfang Data, China National Knowledge Infrastructure, and Chongqing VIP Database. The key words were“arthroscopy, rotator cuff, rehabilitation”. The references of the included literatures were re-retrieved. The deadline of retrieval was August 15, 2012. The included literatures were randomized control ed trials on early and delayed functional exercises after arthroscopic rotator cuff repairs. Methodological quality evaluation, screening and heterogeneous test were conducted. REVMAN5.1 software was utilized to analyze the extracted data.
RESULTS AND CONCLUSION:We included three randomized control ed trials, including 237 patients:119 in the early movement group and 118 in the delayed movement group. During fol ow-up at 1 year after operation, no significant differences in range of motion, pain degree, American Shoulder and Elbow Surgeons Scale, Simple Should Test scores and re-tear rate of rotator cuff were detected between the two groups. Results confirmed that compared with delayed functional exercises, early functional exercises after arthroscopic rotator cuff repair did not have advantages on the improvement of joint function and range of motion, but also did not negatively affect cuff healing. Postoperative rehabilitation can be modified to ensure patient’s compliance.