BACKGROUND:Animal models can be used to study specific scientific problems of intervertebral disc biology.Model of disc degeneration is mainly used to resolve the relevant disease mechanisms and scientific and security issues of the treatment.OBJECTIVE:To summarize currently used experimental animal models of intervertebral disc degeneration study,and to dynamically observe and confirm the pathological process of disc degeneration based on disc imaging,morphology,biomechanics and bi(o)chemicel changes.METHODS:Using "intervertebral disc degeneration,animal models,in vivo,in vitro" in English as the search words,Cochrane Library (No.1 2009),Cochrane Library Database of Controlled Clinical Trials (No.1 2009),MEDLINE from 1990 to March 2009,EMbase from 1990 to March 2009,Current Controlled Trials,and the National Research Register were retrieved.Literature was limited to English language.The disc imaging,morphology,biomechanical end biochemical composition and other indicators,as well as the pathological process of disc degeneration served as the evaluation indices.The articles related to the intervertebral disc cell culture models,the whole disc tissue culture model,mechanical model,injury model,biological model,genetically modified models,spontaneous models were included.The repetitive researches and those unrelated to animal models of intervertebral disc degeneration were excluded.RESULTS AND CONCLUSION:The establishment of a reliable animal model can provide favorable conditions for studying the pathogenesis of intervertebral disc degeneration,at the same time,provides a good experimental vehicle for various researches about the repair treatment of intervertebral disc degeneration.Animal models of intervertebral disc degeneration can be divided into two categories:in vitro models and in vivo models of disc degeneration and repair.The former can be assigned into disc cell culture models and whole disc tissue culture model;the latter is assigned into mechanical models,injury models,biological models,genetically modified models,spontaneous models and so on.The above models are commonly used in the study of the occurring mechanism of disc degeneration,as well as the feasibility and effectiveness of a variety of treatments.However,there is still no generally accepted animal models as an ideal disc degeneration model,various types of models reported have their own advantages and disadvantages.

BACKGROUND:Spinal canal decompression and fusion combined with pedicle screw fixation has become the main method for the treatment of thoracolumbar fracture and dislocation. OBJECTIVE:To restore the vertebral height of the patients with thoracolumbar fracture and dislocation who underwent subtotal resection and decompression through titanium cage packed with autologous cancel ous bone and pedicle screw fixation. METHODS:Thirty-one patients with thoracolumbar fracture and dislocation treated in the Shanghai 6th People’ s Hospital of Shanghai Jiao Tong University from February 2007 to September 2011 were selected. Al the patients received subtotal resection, spinal canal decompression and titanium cage packed with autologous cancel ous bone and pedicle screw fixation. Imaging examination was performed before and after treatment to observe the recovery of vertebral sequence, vertebral height and Cobb angle, as wel as the recovery of nerve function. RESUTLS AND CONCLUSION:The patients were fol owed-up for 12 months, and al the patients healed wel after treated with titanium cage packed with autologous cancel ous bone and pedicle screw fixation, and there was no loosening, shedding or breakage after pedicle screw fixation. During reexamination, the grafts fusion, good deformity correction, basic recovery of vertebral height and good recovery of Cobb angle were observed. Seven cases had neurological function recovery, and among them, six cases raised for one degree, one case raised for two degrees, and another 22 cases without recovery. Case analysis and relative researches showed that subtotal resection and decompression and titanium cage packed with autologous cancel ous bone and pedicle screw fixation can reduce the loss of correction of the patients with thoracolumbar fracture and dislocation, restore the vertebral height, and enhance the stability of the vertebral body.

Finite element analysis can analyze the stress and strain change of object with complex shape,structure,constitution and load condition,and is widely applied to spinal biomechanical studies due to its controllability,reproducibility and versatility in mechanics tests.The article briefly introduced several finite element analysis software,summarized the mechanical characteristics of vertebral body,intervertebral disc,accessories and the ligament and muscle around the spine,and summarized research achievements of finite element analysis in lumbar fusion,concerning the biomechanics of Cage,its influence on lumbar fusion and related surgery choice,dynamic fusion,artificial intervertebral disc and the biomechanical variation of different fusion style after spinal tumor vertebrectomy.Finite element analysis can help understand the spine biomechanics and provide biomechanical reference for lumbar fusion choice.

Concepts and techniques of spinal fusion as a therapeutic modality may date back to the origins of spinal surgery. Spinal fusion has been considered as the standard treatment of progressive deformities,including instability,scoliosis and trauma. In this study,we shall attempt to define and review the bone graft materials,progress on the operative techniques,postoperative complications and related therapy,the latest dynamic fixation,and minimally invasive technique to lumbar spine fusion.

To date, three techniques of total spondelyctomy were used for spinal tumor, including piecemeal technique, eggshell technique and total en bloc spondelyctomy, and each has specific features and indications. Due to limitations of technique, piecemeal technique and eggshell technique are gradually replaced by total en bloc spondelyctomy in treatment of spinal tumor. Moreover, with technical development, application of total en bloc spondelyctomy in treatment of spinal tumor becomes more rigorous and standard. However, it is controversial about its indications and surgical approach. Postoperative spinal stability reconstruction is achieved through various methods according to different conditions.

Objective To implore the feasibility of using single anterior approach surgery for old cervical spine subluxation. Methods From May 2004 to July 2006,16 cases of old cervical spine subluxation underwent cervical spine surgery through anterior approach at least 2 months after injury. During operation, we managed to reconstruct the cervical vertebral body alignment through a special anterior approach decompression, application of retractor instrument, titanium mesh and plate manipulation. Results Follow-ups averaged 8.5(6 to 11) months. The cervical vertebral body alignment Was obtained in all the 16 cases. The osseous fusion was assured in all cases with no instrument failure. The JOA neurological scores were improved from 13.4 preoperatively to 15.9 postoperatively. Conclusion If there is no posterior compression and the posterior structure has a fibrous fusion, the single anterior approach is good enough for the old cervical spine subluxation to maintain alignment and obtain stability, and posterior reduction is not necessary.

Objective To study the different effects of early active mobilization on flexor ten don sheath regeneration when the sheath has bee n partially removed and when the inju red sheath has been sutured.Methods In 192Leghorns involved in this study,the zone II flexor digital profoun d tendons were partially ruptured at their bilateral 3rd digits.Their te ndon sheathes were partially removed or sutured.All the Leghorns were di vided into four groups randomly:active mo bilization-sheath removed(A 1 ),active mobilization-sheath sutur ed(A 2 ),immobilization-sheath removed(C 1 ),and immobilization-sheath suture d(C 2 ).Their toes were harvested in the1st,2nd,3rd,4th,8th and 12thweeks postoperatively.Then morphologic al observations and biomechanical tests were performed.All data were s tatistically analyzed.Results In the 1st week postoperatively,the tendon sheath structure disappeared in the injured areas in both groups of A 2 and C 2 ,while in groups of A 1 and A 2 ,neogenetic tendon sheath formed in t he operation areas.In groups of C 1 and C 2 dense scar tissues developed around the tendon without neogenesis of tendon sheath or sheath-like str ucture.There was no significant dif ference either morphologically or biomechanically between A 1 and A 2 as well as C 1 and C 2 while significant differences were found between A 1 and C 1 as well as A 2 and C 2 .Conclusions The pathologic transformation afte r sheath repair during active mobilization c an be divided into three stages:The s heath decomposed and degenerated in the1st week postoperatively.Early neogenetic sheath formed in 2weeks.The neogenetic sheath matured in 4to 8weeks.Active mobilization to promo te neogenesis of sheath is a key facto r to prevent adhesion.Only tendon sheath repair cannot prevent adhesion effectively.

Objective To evaluate clinical effects of using axonal repair technique (cell surgery) for the treatment of peripheral nerve injuries. Methods 12 patients with 13 injured peripheral nerves were treated with axonal repair technique of soaking the stumps of the nerve in a modified Collins fluid, freezing the stumps with liquid nitrogen, trimming the solidified stumps with a sharp blade, coapting the nerve with glue and two stitches of epineurium, so that the injured peripheral nerves were repaired at the axonal level. The postoperative evaluation was performed at an average of 9.7 months. Results In four of 12 cases operated upon with contralateral C 7 nerve root transfer(C 7 to ulnar nerve), regenerating axons had reached to the ipsilateral sternoclavicular joint or axilla at postoperative 4-7 months, so that the second stage of contralateral C7 nerve root transfer procedure could be performed. In five cases of which the accessory nerves were transferred to suprascapular nerves, the strength of supra-and infraspinatus of 3 patients had recovered to MRC 3-4 at postoperative 16 months, and that of the other two, to MRC 1-2 at 12 months. In one case undergoing the second stage procedure of contralateral C 7 nerve root transfer (ulnar nerve to median nerve), the flexor carpi radialis showed some nerve regeneration shown in EMG at postoperative 4 months. In one case of which phrenic nerve was transferred to the musculocutaneous nerve (the nerve graft 8 cm), the biceps showed some nerves regeneration shown in the EMG 15 months postoperatively. In one patient for whom two digital nerves were repaired, the protective sensation had recovered 3 months postoperatively. Conclusion Axonal repair technique is an effective and practical way for the treatment of peripheral nerve injury.

Objective To study the effect of extract of leave ginkgo biloba (EGb) for protection of the motor and sensory neurons axotomy-induced in rats. Methods Thirty male Sprague-Dawley rats weighing 180－ 220 g (8－ 9 weeks of age), were randomly divided into control group and EGb24/6 group. Models of sciatic nerve injury were established by transection of left sciatic nerve at 0.5 cm away from the points of muscular innervation. The proximal stump of sciatic nerve was double ligated to inhibit nerve regeneration. The distal end of the nerve was implanted into the biceps femoris. Then 2 ml of normal saline was given to control group, and 2 ml of EGb24/6 to the EGb24/6 groups daily. The rats were sacrificed in 7,14,28 days after surgery respectively, and then 4％ paraformaladehyde was perfused transcardially. The L4－ 6 spinal cord and L5 dorsal root ganglion (DRG) were harvested. HE staining and CV technique were used for detection of the motor neurons and compared with contra-lateral side. TUNEL technique was used for detection of apoptotic motor and sensory neurons. Eletron microscopic technique was used for observation of change of L5 DRG neurons. Result The number of motor neurons was significantly higher in EGb24/6 group in each postoperative period than that in control group (P

[Objective]To study the surgical treatment of thoracolumbar fractures in multiple injured patients.[Method]Data from 12 consecutive patients with thoracolumbar fractures and multiple trauma were reviewed retrospectively.Three patients with thoracolumber fractures were complicated by pelvic(acetabular) fracture,11 by lower extremity fracture and 6 by upper extremity fracture.All the patients were treated operatively.The spinal injury and pelvic fractures were first treated.The operation time,bleeding volume as well as Frankle score were recorded.[Result]The average operation time was(202?52)min and the blood loss was(500?325)ml per patient,and the average operation time was 59 min and blood loss was 146 ml for an injury.The average Frankle score increased from 2.8 preoperatirely to 3.5 at 3 months after operation.Bone reunion or fusion was achieved in 8 patients at a one-year follow-up.[Conclusion]Damage control orthopedics should be emphasized for severe polytrama.The operation timing and techniques depend on the characteristics of fractures and the general conditions of the patients.Minimally invasive technique is useful in reducing the operation time and injury reaction,promoting early mobilization and lessening complications.