Lumbar intervertebral disc degeneration assessed by the nine-point system with X-ray / 中国组织工程研究

BACKGROUND: The X-ray 9-point grading system is established based on cervical disc degeneration and its suitability for evaluation of lumbar disc degeneration has not been validated. OBJECTIVE: To investigate the feasibility of the evaluation of lumbar intervertebral disc degeneration using the 9-point grading system with X-ray, and to explore its clinical application value. METHODS: The correlation between 9-point grading system and Pfirrmann system was statistically analyzed. Magnetic resonance imaging (MRI) and X-ray images of 172 cases with lumbar disc degeneration or simple lumbago, who were treated in the Shanghai Changzheng Hospital from June 2013 to June 2016, were retrospectively analyzed. The MRI scores of lumbar disc degeneration were evaluated according to Pfirrmann standard, and the X-ray scores were evaluated according to 9-point grading system. The two groups of scores were respectively analyzed by the correlation and regression tests via Spearman rank sum test with SPSS software. RESULTS AND CONCLUSION: (1) MRI scores (the independent variable X): 2 cases scored 1; 8 cases scored 2; 55 cases scored 3; 84 cases scored 4; 23 cases scored 5. X-ray scores (the dependent variable Y): 2 cases scored 0; 6 cases scored 1; 21 cases scored 2; 43 cases scored 3; 40 cases scored 4; 26 cases scored 5; 16 cases scored 6; 8 cases scored 7; 7 cases scored 8; 3 cases scored 9. (2) The Spearman correlation test showed that significant positive correlation was found between Pfirrmann system and 9-point grading system (P <0.01). Significance test of correlation coefficient proved that there was significant linear correlation between Pfirrmann system and 9-point grading system. Further regression analysis showed the linear regression between Pfirrmann system and 9-point grading system. (3) These findings suggested that Pfirrmann system and X-ray 9-point grading system had a good consistency in evaluating lumbar disc degeneration. As a scientific, fast and effective evaluation method, the X-ray 9-point grading system has a certain reference value in the diagnoses of lumbar degenerative diseases.

Short-term clinical results of interspinous dynamic fixation of Coflex for the prevention of adjacent segment degeneration after lumbar fusion / 中华外科杂志

<p><b>OBJECTIVE</b>To observe the short-term clinical results of the adjacent segment degeneration after the implantation of Coflex system at the interspinous space of adjacent segment to lumbar fusion.</p><p><b>METHODS</b>Fifty patients with grade III disc (Thompson MRI classification) of adjacent segment to lumbar fusion were included and divided alternately into two groups according to the order of hospitalization from January to November 2009. Coflex system was implanted at the interspinous space of adjacent segment to lumbar fusion in 25 patients as Coflex group, the other 25 patients did not have any surgical treatment were as control group. The followed up time was 2 years. Visual analogue scale (VAS) score of low back pain, changes of disc height and motion range of adjacent segment to lumbar fusion on X-ray imaging were evaluated by independent sample t-test or paired samples t-test.</p><p><b>RESULTS</b>There were 22 patients in Coflex group and 21 patients in control group were followed up 2 years post-operation. The difference of VAS score between two groups was no significance (P > 0.05). In Coflex group, the change of postoperative disc height was no significance (P > 0.05), but the motion range was significantly reduced to 47% of the preoperative value (t = 7.99, P < 0.05). In control group, the postoperative disc height decreased slightly, without significant difference to the preoperative value (P > 0.05). Between the two groups, no differences of the disc height and motion range were found before operation, but the differences of the disc height changes (t = 6.7, P < 0.05) and motion rang (t = -14.5, P < 0.05) were significant in 2 years post-operation. No complications such as Coflex system loosen, immigration and spinal process fracture were occurred.</p><p><b>CONCLUSIONS</b>Coflex system can obviously limit the motion range and maintain the disc space height of adjacent segment to lumbar fusion, and prevent its degeneration in some degree.</p>

Finite element analysis on intra-segmental fixation and inter-segmental fixation for lumbar spondylolysis / 医用生物力学

Objective To compare the stresses on the end plate of adjacent lumbar vertebrae between intra-segmental fixation and inter-segmental fixation in treating lumbar spondylolysis by three-dimensional finite element analysis. Method Based on the established finite element model of L4 lumbar spondylolysis, the lumbar internal fixation such as rods and trans-pedicle screws were reconstructed to make the finite element models of intra segmental and inter segmental internal fixation with the same constraint and loading conditions. The stresses on endplate of adjacent lumbar vertebrae of finite element models were measured under three mechanical conditions:spondylolysis, intra-segmental fixation and inter-segmental fixation. Results High stresses were observed under two kinds of internal fixation conditions compared with the spondylolysis condition at the lower endplate of L4 under axial loading(P<0.05). The stresses at the lower endplate of L4 under intra segmental fixation condition were similar as that of the spondylolysis condition under flexion, extension and lateral bending loading. With the same loading, higher stresses were observed under inter-segmental fixation condition compared with the spondylolysis condition, and so did the lower stresses at upper endplate of S1(P<0.05). The lower stresses at the upper endplate of S1 under intra-segmental fixation condition were observed compared with the other two conditions under rotating loading (P<0.05). Conclusions The intra segmental fixation can not only provide stability for lumbar spondylolysis under axial, flexion, extension, lateral bending,but also preserve the normal activity at adjacent disc levels, especially under rotating loading.

Current study and research progress of whiplash injury of cervical vertebrae / 中国骨伤

Whiplash injury is a common injures in our daily lives, but the mechanism of it and the best treatment is largely unknown. The development of chronic pain and disability following whiplash injury is not uncommon and results in substantial social and economic costs. Clinical manifestation and recovery time are difference, which make it difficult for doctor diagnosis and treatment. The current study have shown that the social class, severity of collision, compensation and lawsuit, physical and psychological factors were relevant predictors for the outcome of whiplash. This article is try to overview the status quo of the whiplash injury.

Biomechanical performance of different wires and cable fixation devices in posterior instrumentation for atlantoaxial instability / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the biomechanical performances of different wires and cable fixation devices in posterior instrumentation for atlantoaxial instability, and test the effect of different fixation strengths and fixation approaches on the surgical outcomes.</p><p><b>METHODS</b>Six specimens of the atlantoaxial complex (C0-C3) were used to establish models of the normal complex, unstable complex (type II odontoid fracture) and fixed complex. On the wd-5 mechanical testing machine, the parameters including the strength and rigidity of anti-rotation, change and strength of stress, and stability were measured for the normal complex, atlantoaxial instability complex, the new type titanium cable fixation system, Atlas titanium cable, Songer titanium cable, and stainless wire.</p><p><b>RESULTS</b>The strength and rigidity of anti-rotation, change and strength of stress, stability of flexion, extension and lateral bending of the unstable atlantoaxial complex fixed by the new double locking titanium cable fixation system were superior to those of the Songer or Atlas titanium cable (P<0.05) and medical stainless wire (P<0.05). Simultaneous cable fastening on both sides resulted in better fixation effect than successive cable fastening (P<0.05). Better fixation effect was achieved by fastening the specimen following a rest (P<0.05).</p><p><b>CONCLUSIONS</b>The fixation effects can be enhanced by increased fastening strengths. The new type double locking titanium cable fixation system has better biomechanical performance than the conventional Songer and Atlas titanium cables. Fastening the unstable specimens after a rest following simultaneous fastening of the specimen on both sides produces better fixation effect.</p>

Biomechanics of lumbar spondylolysis : Finite element modeling and validation / 医用生物力学

Objectives To construct three-dimensional finite element model of lumbar spondylolysis, then to verify its validity by comparison of biomechanics in vitro. Methods According to the radiological data of a patient with lumbar spondylolysis, the bone and intervertebral disc of L4-S1 were reconstructed by Simpleware software. The lumbar attaching ligaments and articular capsule were added into simulating model by Ansys software. Finally, the three-dimensional finite element model of lumbar spondylolysis was simulated successfully, and validated by lumbar spondylolysis biomechanical experiment in vitro. Results The reconstruction of digital model is contained of the bones of lumbar spine which includes of vertebral cortical bone, cancellous bone, facet joint, pedicle, lamina, transverse process and spinous process,as well as annulus fibrosus, nucleus pulposus,superior and inferior end-plates. Besides, anterior and posterior longitudinal ligaments, flavum ligament, supraspinal and interspinal ligaments and articular capsule of facet joint are also attached. The model consisted of 281,261 nodes and 661,150 elements. Imitation of spondylolysis is well done in this model. The validity of the model is verify by comparison of the results of biomechanics in vitro which involved in the trends under loading of stress/strain of L4 inferior facet process, L5 superior and inferior facet process, S1 superior facet process and the trend of stress/strain of lateral and medial L4 inferior facet process. Conclusions Lumbar spondylolysis is reconstructed to three-dimensional model using finite element analysis, and can be further used in the research of biomechanics of lumbar spondylolysis.

The surgical treatment of severe adolescent idiopathic cervical kyphosis / 中华外科杂志

<p><b>OBJECTIVE</b>To summarize the clinical characteristics of severe adolescent idiopathic cervical kyphosis and the operation method.</p><p><b>METHODS</b>A retrospective study was performed in 12 adolescent patients with severe cervical kyphosis treated from July 2003 to January 2007. Preoperative the Cobb angle of kyphosis range from 55 degrees to 73 degrees (average 61 degrees ). According to the angles between the posterior vertebral body tangents at every involved level on lateral cervical radiograph in extension, the osteotomy angles and range of lamina and facet were decided. The anterior release and posterior osteotomy were performed firstly. Then skull traction was maintained in order to correct the deformity as long as possible, fusion and internal fixation was completed after 7-10 days. The cervical coronal and sagittal planes X-rays and the MR were hold after operation 3 days, 3 months, 6 months, 1 year and 2 years. At the same time the treatment result, bone fusion and the instrumentation were followed up, and the symptoms were compared between pre-operation and post-operation.</p><p><b>RESULTS</b>The defect appearance of the patients was improved significantly, with the total disappearance of neck pain and improvement of nerve function. Post-operational cervical spine MR showed that the physiological curve of cervical spine was restored, cerebral spinal fluid line was clear in the kyphosis area and no spinal cord compression was found. X-ray imaging of post-operation 3 d showed that Cobb angle ranged from -12.3 degrees to 11.2 degrees with an average of -2.0 degrees . Beside one patient's AISA score was D, other patient's AISA score was E.</p><p><b>CONCLUSIONS</b>The severe adolescent idiopathic cervical kyphosis has its own clinical manifestation. It is an ideal treatment to completely assess the deformity, have staging operation and skull traction between two operations.</p>

The clinical features and surgical treatment strategies of cervical kyphosis / 中华外科杂志

<p><b>OBJECTIVE</b>To analyze the clinical characteristics and the surgical treatment strategy of cervical kyphosis.</p><p><b>METHODS</b>From March 2006 to October 2009, 31 cases of cervical kyphosis were treated. According to the clinical features and imaging findings, different treatment methods were used. There were 9 patients in operation group, including 4 male and 5 female patients, aged from 17 to 72 years (average age of 35 years). Among them, 5 cases were idiopathic kyphosis and 4 cases were caused by laminectomy or other reasons. There were 22 patients in conservative treatment group, including 11 male and 11 female patients, aged from 14 to 40 years (average age of 29 years), who were all idiopathic cervical kyphosis. Before and 1 week after operation, clinical assessment were taken for the patients in operation group using Spinal Cord Injuries Classification Standard of American Spinal Injury Association (AISA). During the periodic review, the anteroposterior, normal sagittal films of cervical spine were taken. At 1 week and every 6 months after operation, MRI films were also taken. These films were studied to evaluate the effects of the operations. In the conservative group, assessment of treatment results by studying anteroposterior and normal lateral views of cervical spine were were taken every month. The clinical characteristics and the surgical treatment strategies of these patients were analyzed.</p><p><b>RESULTS</b>In operation group, 9 cases were followed up for 6 to 18 months, all patients did not failed in internal fixation and fusion. AISA neurological score and neurological function significantly improved. Three days after operation the average Cobb angle was -1.29 ° (preoperative 54.24 °). In conservative group, the average Cobb angle was -5.41 ° (before treatment 11.20 °) 4 months after the treatment. The symptoms of neck shoulder and back pain disappeared, and all patients were followed up for 3 to 24 months, with no recurrence of symptoms.</p><p><b>CONCLUSIONS</b>In the early period of cervical kyphosis, adopt postural therapy, plaster braces to correct an imbalance in cervical spine biomechanics can prevent deformity development. According to patients' clinical characteristics, choosing individual treatment programs can correct the severe cervical kyphosis and achieve good outcome.</p>

Biomechanics of lumbar spondylolysis: Finite element modeling and validation / 医用生物力学

Objective To construct three-dimensional finite element model of lumbar spondylolysis,then to verify its validity by comparison of biomechanics in vitro.Method According to the radiological data of a patient with lumbar spondylolysis,the bone and intervertebral disc of L4-S1 were reconstructed by Simpleware software.The lumbar attaching ligaments and articular capsule were added into simulating model by Ansys software.The three-dimensional finite element model of lumbar spondylolysis was finally simulated successfully,and validated by lumbar spondylolysis biomechanical experiment in vitro.Results The reconstruction of digital model contained the bones of lumbar spine which include vertebral cortical bone,cancellous bone,facet joint,pedicle,lamina,transverse process and spinous process,as well as the annulus fibrosus,nucleus pulposus,superior and inferior end-plates.Besides,anterior and posterior longitudinal ligaments,flavum ligament,supraspinal and interspinal ligaments and articular capsule of facet joint are also attached.The model consisted of 281,261 nodes and 661,150 elements.Imitation of spondylolysis is well done in this model.The validity of the model was verified by comparison of the results of biomechanics in vitro which involved in the trends under loading of stress/strain of L4 inferior facet process,L5 superior and inferior facet process,S1 superior facet process and the trends of stress/strain of lateral and medial L4 inferior facet process.Conclusions Three-dimensional model of lumbar spondylolysis is reconstructed using finite element analysis,and can be further used in the research in biomechanics of lumbar spondylolysis.

Biomechanics of lumbar spondylolysis: Finite element modeling and validation / 医用生物力学

Objective To construct three-dimensional finite element model of lumbar spondylolysis,then to verify its validity by comparison of biomechanics in vitro.Method According to the radiological data of a patient with lumbar spondylolysis,the bone and intervertebral disc of L4-S1 were reconstructed by Simpleware software.The lumbar attaching ligaments and articular capsule were added into simulating model by Ansys software.The three-dimensional finite element model of lumbar spondylolysis was finally simulated successfully,and validated by lumbar spondylolysis biomechanical experiment in vitro.Results The reconstruction of digital model contained the bones of lumbar spine which include vertebral cortical bone,cancellous bone,facet joint,pedicle,lamina,transverse process and spinous process,as well as the annulus fibrosus,nucleus pulposus,superior and inferior end-plates.Besides,anterior and posterior longitudinal ligaments,flavum ligament,supraspinal and interspinal ligaments and articular capsule of facet joint are also attached.The model consisted of 281,261 nodes and 661,150 elements.Imitation of spondylolysis is well done in this model.The validity of the model was verified by comparison of the results of biomechanics in vitro which involved in the trends under loading of stress/strain of L4 inferior facet process,L5 superior and inferior facet process,S1 superior facet process and the trends of stress/strain of lateral and medial L4 inferior facet process.Conclusions Three-dimensional model of lumbar spondylolysis is reconstructed using finite element analysis,and can be further used in the research in biomechanics of lumbar spondylolysis.

Clinical significance of cervical vertebral flexion and extension spatial alignment changes.

STUDY DESIGN: Radiographic review. OBJECTIVE: To study changes in alignment and curvature of the cervical vertebral column in the sagittal plane, and to provide references for the orthopedic treatment of cervical kyphosis. SUMMARY AND BACKGROUND DATA: There are few reports analyzing changes of the vertebral body itself or changes in their relationships between separate vertebrae. To understand cervical vertebrae and curvature dynamic variation patterns in the sagittal plane and provide a theoretical reference for orthopedic correction of cervical kyphosis, we measured spatial position and alignment of the cervical vertebrae on sagittal plane films of various postures. METHOD: Blind repeated measures design analysis of sagittal view standard lateral, hyper flexion, and hyper extension cervical spine of 60 healthy subjects measuring spatial alignment angle of C2 to C7 vertebral bodies in the sagittal plain ( angleA), C2 to C7 inferior terminal lamina tilt angle of ( angleB), and segmental intervertebral space angles C2/3 to C6/7 ( angleC) calculating flexion and extension amplitude changes in angleA, angleB, and angleC. Cervical curve apex was determined using Borden's method to compare change and distribution characteristics. RESULTS.: Segmental angleA is a positive mean value that increases from C2 to C7 when in the upright position. In hyper extension, mean angleA value decreases with gradual amplitude decrease from C2 to C7; however, a gradual overall increasing pattern is observed for mean angleA from C2 to C7. In hyper flexion, segmental angleA mean value increases with gradual amplitude decrease from C2 to C7, whereas with decreasing angular measurements from C2 to C7. angleB follows similar change regularities as angleA with a larger mean value than angleA. During maximum extension and maximum flexion, angleD is equal to angleE. For example: C2 angleD = C2 variable angleA; C2 angleE angle(C3 variable angleA + C2/3 variable angleC); and C2 angleD = C2 angleE. Cervical spine curve apex is mainly distributed between C4 and C5 on standard, hyper extension and hyper flexion lateral view. CONCLUSION: Dynamic cervical curvature changes based on a central apex, stems from vertebral rotation and displacement in the sagittal plane. Our study reveals variation patterns of dynamic cervical spine sagittal alignment and curvature, providing vertebral spatial alignment value as reference for orthopedic cervical kyphosis corrective surgery.

Reconstructive techniques study after anterior decompression of multilevel cervical spondylotic myelopathy.

STUDY DESIGN: Retrospectively compared 2 reconstructive techniques after the anterior decompression of multilevel cervical spondylotic myelopathy. OBJECTIVE: To clinically compare the biomechanical stability and neurologic results of 2 reconstructive techniques after the anterior decompression of multilevel cervical spondylotic myelopathy retrospectively. SUMMARY OF BACKGROUND DATA: Previous studies comparing different reconstruction techniques after the anterior decompression of multilevel cervical spondylotic myelopathy have yielded mixed results. Some studies have reported a high incidence of graft-plate extrusion when 2 or more corpectomies are performed and reconstructed with a long segmental anterior plate fixation that spans the strut graft without supplemental posterior cervical fixation, a standalone cage and segmental plate fixation after combination 1 level discectomy and 1 level corpectomy used to treat multilevel cervical spondylotic myelopathy were reported have no evidence of late-onset instrumentation-related failure, although 2 techniques have never been directly compared in a consecutive series of patients clinically. METHODS: A retrospective study of 59 patients with multilevel (3 levels) cervical spondylotic myelopathy treated with 1 of 2 anterior decompression and reconstruction methods were compared. Copectomy method (39 patients) is 2-level corpectomies and long segment end-construct plate fixation; hybrid method (20 patients) is standalone cage and segmental plate fixation after 1-level discectomy combined with 1-level corpectomy. RESULTS: The follow-up (mean18 mo) results show both methods had similar, satisfactory recovery of neurologic function (P>0.05). There were 7 cases of graft/plate migrations or dislodgments (17.9%) and 4 of these required revision surgery among 39 patients with corpectomy method, as compared with no graft/implant-related complications or nonunion among 20 patients with hybrid method (P<0.001). CONCLUSIONS: This study clearly demonstrates that, adequate decompression can be achieved for the multilevel cervical spondylotic myelopathy with both methods, and the hybrid method offers better biomechanical stability and fusion results than the corpectomy method, and obviates the need for staged circumferential procedures.

Cauda equina syndrome: a review of clinical progress / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To review the literature on the clinical progress in cauda equina syndrome (CES), including the epidemic history, pathogenesis, diagnosis, treatment policy and prognosis. Data sources All reports on CES in the literature were searched in PubMed, Ovid, Springer, Elsevier, and the Chinese Biomedical Literature Disk using the key terms "cauda equina syndrome", "diagnosis", "treatment", "prognosis" and "evidence-based medicine". Study selection Original milestone articles and critical reviews written by major pioneer investigators about the cauda equina syndrome were selected.</p><p><b>RESULTS</b>CES is rare, both atraumatically and traumatically. Males and females are equally affected. The incidence of CES is variable, depending on the etiology of the syndrome. The most common cause of CES is herniation of a lumbar intervertebral disc. CES symptoms may have sudden onset and evolve rapidly or sometimes chronic ally. Each type of CES has different typical signs and symptoms. Low back pain may be the most significant symptoms, accompanied by sciatica, lower extremities weakness, saddle or perianal hypoesthesia, sexual impotence, and sphincter dysfunction. MRI is usually the preferred investigation approach. Patients who have had CES are difficult to return to a normal status.</p><p><b>CONCLUSIONS</b>The diagnosis of CES is primarily based on a careful history inquiry and clinical examination, assisted by elective radiologic investigations. Early diagnosis and early surgical decompression are crucial for a favorable outcome in most CES cases.</p>

Anterior cervical locking plate-related complications; prevention and treatment recommendations.

A retrospective study evaluating complications in 2,233 consecutive patients of subaxial cervical disorders treated with an anterior cervical locking plate was performed, and recommendations for prevention and treatment were made. The average length of follow-up was 1.3 years. Any loosening or breaking of the plates and screws or malpositions that threatened tracheoesophageal or neurovascular structures were defined as the complications. There were 239 cases (10.7%) with different kinds of complications. The complications included oblique plating in 56 cases in which the screw could irritate the nerve root. Screws were driven into the disc space in four cases, which ultimately led to plate loosening. Screws penetrated the endplate or passed excessively close to it producing a triangle fracture in 19 cases. Loosening or breaking of the plate and the screw was found in 115 cases. These phenomena were always associated with non-union. Three oesophageal perforations occurred and conservative treatments proved effective. Finally, overlong plates impinged on the adjacent level in 14 cases and promoted disc degeneration ultimately leading to revision surgery. Good training and careful operation may help to decrease the complication rate. Most hardware complications are not symptomatic and can be treated conservatively. Only a few of them need immediate reoperation.

Clinical research of delayed hyperextension injury concomitance spinal cord injury of cervical spine / 中华外科杂志

<p><b>OBJECTIVE</b>To discuss Clinic feature and turnover of delayed hyperextension injury concomitance spinal cord injury of cervical spine.</p><p><b>METHODS</b>The clinic data of 30 patients delayed hyperextension injury of cervical spine were reviewed and analyzed. Course of disease was from 3 months to 8 years. Thirty patients were divided into three groups according to course of disease. The first group, 3 - 6 months, 17 cases; the second group, 6 - 12 months, 8 cases; the third group, 12 months-8 years, 5 cases. Neurological function improvement rates were evaluated according to the JOA scores at preoperative, 3 months and 1 year post operation, and complications were observed in three groups. Twenty-six cases were treated with anterior decompression, bone graft and plate fixation. Four cases were treated with posterior decompression, bone graft and plate fixation.</p><p><b>RESULTS</b>The patient number of the three group exist with statistical significance. Thirty patients were followed up for 18 - 39 months, 23 months on average. Neurological function recovery rates were 23.8% in the first group, 53.9% in the second group and 54.3% in the third group at 1 year post operation. JOA scores of the first group and the second group with statistical significance at 3 months and 1 year post operation. JOA scores of the first group and the third group with statistical significance at 3 months and 1 year post operation. JOA scores of the second group and the third group without statistical significance at 3 months and 1 year post operation.</p><p><b>CONCLUSIONS</b>Incidence of hyperextension injury associated with spinal cord injury of cervical spine would degrade along with course of disease prolong. If delayed spinal cord injury occurred earlier, the patient's condition was severer and badly improvement rate.</p>

Sagittal diameters measurements on MR of the cervical spinal cord in normal subjects / 中华外科杂志

<p><b>OBJECTIVE</b>To offer normal reference of diameter of the cervical spinal cord and available diameter of cervical spinal canal and to screen scientific radiographic criteria to define and quantify cervical spinal cord disease.</p><p><b>METHODS</b>The magnetic resonance images of 120 normal people had been measured. The data of diameters of cervical spinal cord, CSF, M, the ratio of diameters of cord and CSF, and the ratio of diameters of cord and M had been collected and statistical analysis was made. And the relationships between the data above and each of gender, the length of C-spine and age were evaluated. In addition, the ratio of diameters of cord and CSF, and the ratio of diameters of cord and M was evaluated.</p><p><b>RESULTS</b>The study showed that in healthy people, the diameters of cervical spinal cord, CSF and M was larger in the males than in the females, decreased with age, and increased with the length of C-spine but the diameter of CSF. And the ratio of diameters of cord and CSF increased with age and not affected by the length of C-spine. However, the ratio of diameters of cord and M was not affected by age and the length of C-spine.</p><p><b>CONCLUSION</b>The ratio of diameters of cord and M is not affected by individual variation and can be used to evaluate cervical spinal cord atrophy, compression and impaired in patients with cervical myelopathy and can be important information in looking for clinically critical points.</p>

Surgical treatment and prognosis of aneurysmal bone cyst in mobile spine / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the effects of surgical treatment and prognosis of aneurysmal bone cyst (ABC) in mobile spine.</p><p><b>METHODS</b>A total of 12 patients with ABC were operated on from 1996 to 2006, and the clinical data were retrospectively reviewed. The patients included 7 male and 5 female, aged from 16 to 52 years (mean, 29 years). Surgical interventions were selected according to WBB criteria. Seven patients underwent total spondylectomy, four underwent resection of posterior arch, one patient received sagittal resection only. Anti-poster or post-lateral approach reconstruction with bone-graft or bone cement and transpedicular screws fixation were performed in the cases. Eight cases received radiotherapy after the operation.</p><p><b>RESULTS</b>The mean operation blood lose was 3210 ml. The patients were followed-up for 10 to 116 months (mean, 41.8 months). Seven patients got complete recover of spinal cord function, 4 patients experienced local recurrence in 1-2 years post operation. One patient died of multiple metastasis of chondrosarcoma after radiotherapy.</p><p><b>CONCLUSIONS</b>ABC in spine is an aggressive disease with high local recurrence rate. Enbloc if possible provides the best result, with excellent prognosis. Radiotherapy should be selected carefully.</p>

Change of motor evoked potential of the diaphragm after graded upper cervical spinal cord injury in rats / 中华外科杂志

<p><b>OBJECTIVE</b>To study the change of motor evoked potential of the diaphragm after graded upper cervical cord injuries and analyze the prognosis of the respiratory function after upper cervical cord injuries by MEP.</p><p><b>METHODS</b>The C(3, 4) spinal cord of 40 SD rats were injured with modified Allen method by weight drop force of 30 gcf, 50 gcf, 80 gcf, 100 gcf. The change of latent and amplitude of MEP of the diaphragm was observed before and after the spinal cord injuries (followed up for 1 month). At the same time, the femoral arterial blood of 0.2 ml was drawn. The pH value, the partial pressure of oxygen, the partial pressure of carbon dioxide, and the saturation of the blood oxygen were monitored. The change of the respiratory function was evaluated in the rats after cervical cord injuries. The relationship between the recovery of the respiratory function and the latent or amplitude was analyzed.</p><p><b>RESULTS</b>The MEP wave of the diaphragm was stable before the upper cervical spinal cord injury in the rats. It was usually composed of a positive and negative wave. The latent period and peak-peak amplitude of wave were (3.13 +/- 0.29) ms and (6.78 +/- 3.48) mv. The latent period of the diaphragms MEP in rats change with graded upper cervical cord injuries significantly, the more sever the injury, the longer the latent period. There were obvious relationship between the change of the latent period and the recovery of the respiratory function. When the latent period prolonged 101%, the respiratory function is hardly to recovery.</p><p><b>CONCLUSIONS</b>MEP can objectively and sensitively reflect the injury extent of the respiratory function when upper cervical cord is injured. It would be a reliable index to evaluate the long-term prognosis of respiratory function.</p>

The assessment of accuracy and safety of thoracic pedicle screw placement in the fracture of thoracic spine / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the accuracy and safety of pedicle screw placement in the fracture of thoracic spine.</p><p><b>METHODS</b>On the basis of imaging for the fracture of thoracic spine of 50 cases, the screw prick point, angle, depth and diameter were measured and defined on the thoracic vertebrae pedicle by CT thin-slice scan in standard prone in all cases. The accuracy and safety of screws placement was evaluated with X-ray and CT thin-slice scan in all cases postoperative.</p><p><b>RESULTS</b>Among of 240 thoracic pedicle screws that were inserted in 50 cases, 220 screws (91.7%) were fully contained within the cortical boundaries of the pedicle, 20 screws (8.3%) were misplaced, 7 screws (2.9%) laterally, 5 screws (2.1%) anterolateral and 2 (0.8%) of it demonstrated aortic abutment, 3 screws (1.3%) caudad perforations of the pedicle, 3 screws (1.3%) expended the wall of the pedicle to inside, 2 screws (0.8%) were misplaced in vertebral canal according to X ray and CT thin-slice scan. When comparing screws in different part of thoracic, there was a significant difference.</p><p><b>CONCLUSIONS</b>Preoperative CT measurement of the thoracic pedicle in the treatment of thoracic fracture can provide important data. It is important factors for thoracic pedicle screws that can be placed safety with guided by intraoperative fluoroscopic imaging and anatomic landmarks. CT thin-slice scan can evaluate accuracy misplace of thoracic pedicle screws, and show anatomic place surroundings of thoracic pedicle screws postoperative. More misplaced screws are seen proximally.</p>

In vivo experimental study of hat type cervical intervertebral fusion cage / 中华外科杂志

<p><b>OBJECTIVE</b>To compare the characteristics of interbody fusion achieved using hat type cervical intervertebral fusion cage (HCIFC) with those of an autologous tricortical iliac crest graft, Harms cage and Carbon cage in a goat cervical spine model.</p><p><b>METHODS</b>Thirty-two goats underwent C(3, 4) discectomy and fusion in which the following were used: Group 1, autologous tricortical iliac crest bone graft (8 goats); Group 2, Harms cage filled with autologous iliac crest graft (8 goats); Group 3, Carbon cage filled with autologous iliac bone (8 goats); Group 4, HCIFC filled with autologous iliac graft (8 goats). Radiography was performed pre- and postoperatively and after 1, 2, 4, 8, and 12 weeks. At the same time points, disc space height, intervertebral angle, and lordosis angle were measured. After 12 weeks, the goats were killed and fusion sites were harvested. Biomechanical testing was performed in flexion, extension, axial rotation, and lateral bending to determine the stiffness and range of motion. All cervical fusion specimens underwent histomorphological analysis.</p><p><b>RESULTS</b>One week after operation, the DSH, IVA and LA of HCIFC and Carbon cage were statistically greater than those of autologous iliac bone graft and Harms cage. Significantly higher values for disc space height, intervertebral angle and lordosis angle were shown in cage-treated goats than in those that received bone graft over a 12-week period. The stiffness of Harms cage in axial rotation and later bending were statistically greater than that of other groups. Radiographic and histomorphologic evaluation showed better fusion results in cage groups than in autologous bone group.</p><p><b>CONCLUSIONS</b>HCIFC can provide a good intervertebral distractability and enough biomechanical stability for cervical fusion.</p>