Biomechanical Study on Atlantoaxial Dislocation Combined with Basilar Invagination by Different Posterior Internal Fixation Methods / 医用生物力学

Objective To investigate biomechanical differences of two posterior occipitocervical internal fixation techniques for treating basilar invagination with atlantoaxial dislocation (BI-AAD). Methods Intra-articular cage + posterior occipital plate+C2 pedicle screw (Cage+C2PS+OP), and intra-articular cage+C1 lateral mass screw+C2PS (Cage+C1LMS+C2PS) models were established based on occipitocervical CT data of the BI-AAD and clinical operation scheme, and the stability of atlantoaxial joint and stress distribution characteristics of C2 endplate and implanted instruments under different motion states were analyzed. Results Compared with the Cage+C1LMS+C2PS model, the atlantoaxial range of motion ( ROM) under flexion, extension, lateral bending and axial rotation in the Cage+C2PS+OP model were reduced by 5. 26% , 33. 33% , 43. 75% , -5. 56% , and stress peak of screw-rod fixation system were reduced by 47. 81% , 60. 90% , 48. 45% , 39. 14% , respectively. Under two internal fixation modes, stresses of C2 endplate and cage were mainly distributed on the compressive side during the motion, and both the screw-bone interface and the caudal side of screw subjected to large loading. Conclusions Two internal fixation methods could provide similar stability. However, the stress concentration of screw-rod system was more obvious and the possibility of screw loosening and fracture was greater under Cage+ C1LMS+C2PS fixation.

Surgical Treatment of Ten Adults with Spinal Extradural Meningeal Cysts in the Thoracolumbar Spine

Objective@#: To retrospectively analyze the clinical characteristics and surgical experience of 10 adults with spinal extradural meningeal cysts (SEMCs) in the thoracolumbar spine which may further provide evidence for surgical decision-making. @*Methods@#: Ten adults with SEMCs in the thoracolumbar spine were surgically treated and enrolled in this study. Clinical manifestations, imaging data, intraoperative findings and postoperative outcome were recorded. @*Results@#: Clinical manifestations of SEMCs included motor and sensory dysfunction of the lower limbs and urination and defecation disturbance. The cysts presented as intraspinal occupying lesions dorsal to the spine, ranging from the T8 to L3 level. Defects of eight cases were found on preoperative magnetic resonance imaging (MRI). Selective hemilaminectomy or laminectomy were used to reveal the defect within the cyst, which was further sutured with microscopic technique. The final outcome was excellent or good in seven cases and fair in three cases. No recurrence was observed during follow-up. @*Conclusion@#: SEMCs are rare intraspinal cystic lesions. Radiography and MRI are clinically practical methods to assess defects within SEMCs. Selective hemilaminectomy or laminectomy may reduce surgical trauma. Detection and microscopic suturing of the defects are the key steps to adequately decompress the nervous tissue and prevent postoperative recurrence.

Reduction of the atlantoaxial dislocation associated with basilar invagination through single-stage posterior approach: using Xuanwu occipital-cervical reduction surgical suite / 中华外科杂志

Objective@#To examine the effect of posterior reduction in atlantoaxial dislocation (AAD) associated with basilar invagination(BI) using Xuanwu occipital-cervical fusion system in single stage.@*Methods@#Thirty-seven AAD accompanied with BI cases treated at Department of Neurosurgery, Xuanwu Hospital, Capital Medical Universiy and the Second Hospital of Hebei Medical University were retrospective analyzed. There were 15 males and 22 females with age of (42.3±12.3) years (range: 18-69 years). All the cases had congenital osseous abnormalities, such as assimilation of atlas and abnormal cervical fusion. Anterior tissue was released through posterior route followed by cage implantation into facet joint and occipital-cervical fixation with cantilever technique. The clinical results were evaluated using Japanese Orthopedic Association scale(JOA) and the main radiological measurements including anterior atlantodental interval (ADI), the distance of odontoid tip above Chamberlain line, clivus-canal angle(CCA) and the length of syrinx were collected. The preoperative and postoperative JOA score and radiological measurements were compared by paired t-test.@*Results@#The mean JOA score of the patients increased from 10.5 to 14.4 at the one-year follow-up(t=14.3, P=0.00). Complete reduction of AAD and BI was achieved in 34 patients.The mean clivus-canal angle improved from (118.0±6.5) degrees preoperative to (143.7±5.0) degrees postoperative(t=6.2, P=0.00). Shrinkage of the syrinx was observed 1 week after surgery in 24 patients, and 6 months in 31 patients.Twenty-eight patients achieved bone fusion 6 months after surgery. All the patients achieved bone fusion 12 months after surgery. One-side vertebral artery occlusion was diagnosed in 1 case postoperatively for transient dizziness, and relieved in 2 weeks.Two patients developed moderate neck pain after surgery, and relieved in 1 month. No implant failure, spacer subsidence or infection was observed.@*Conclusions@#The treatment of AAD associated with BI using Xuanwu occipital-cervical fusion system from posterior approach in single stage is effective and safe. Cage implantation intraarticularly and fixation with cantilever technique achieve complete reduction in most cases.

An analysis of surgical outcome and influencing factors in patients of congenital basilar invagination with atlantal-axial dislocation: report of 120 cases / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the surgical outcome and its influencing factors in patients of congenital basilar invagination (BI) with atlanto-axial dislocation (AAD).</p><p><b>METHODS</b>From May 2004 to August 2010, 120 patients who had BI with AAD were surgically treated with direct posterior intraoperative distraction-reduction and fixation technique, 93 patients were successfully followed up by means of questionnaire survey, telephone and clinical evaluation. Pre- and postoperative dynamic cervical X-rays, computed tomographic scans, 3-dimentional reconstruction views and magnetic resonance imaging were performed. Pre- and postoperative Japanese Orthopaedic Association (JOA) score, distance between odontoid tip and Chamberlain's line and atlantodental interval were measured to evaluate the surgical result. Statistical analysis was performed by means of paired t test and Pearson Correlation analysis.</p><p><b>RESULTS</b>There were 93 cases were followed up for 24-99 months with an average of 46.5 months. Until the final follow-up, clinical symptoms were improved in 79 patients (84.9%), and were stable in 7 patients (7.5%) and deteriorated in 4 patients (4.3%). Three patients died postoperatively (3.2%). Patients without intramedullary signal intensity change (ISIC) had better surgical outcome. Patients with compression from anterior odontoid tip and posterior bone margin of occipital foramen had the worst surgical outcome (F = 3.987, P < 0.01). Overall, good decompression and bone fusion were shown on postoperative image in 87 patients (93.5%). There were 3 deaths in this series because of basilar artery thrombosis, posterior fossa hematoma and unknown reasons each.</p><p><b>CONCLUSIONS</b>The direct posterior intraoperative distraction-reduction and fixation technique is an effective simple and safe method for the treatment of BI with AAD. Anterior compression from odontoid tip and posterior compression from bone margin of occipital foramen-atlantal posterior arch play important roles in its developing mechanism. ISIC on MRI is a predictive factor for the worse surgical outcome.</p>

Culture and characterization of and lentiviral vectors mediated glial cell derived neurotrophic factor expression in mesenchymal stem cells from human umbilical cord blood / 中国医学科学院学报

<p><b>OBJECTIVE</b>To isolate and culture mesenchymal stem cells from umbilical cord blood (UCB-MSCs), study its biological characterization in vitro, transfect UCB-MSCs using lentiviral vectors encoding glial cell derived neurotrophic factor (GDNF) gene, evaluate the biological function change of UCB-MSCs, and detect GDNF expression level in vitro.</p><p><b>METHODS</b>We isolated monocyte by Ficoll density gradient, separated two kinds of adherent cells through different trypsin digestion time, and detected the cells surface markers by fluorescence activated cell sorting when it was proliferated for P7 passages. At the same time, we sub-cloned GDNF gene into lentiviral vectors and packaged lentiviral supernatant through three plasmids co-transfection method, then transfected the UCB-MSCs using lentiviral vectors encoding GDNF at different multiplicity of infection, and evaluated the change of biological function by observing the ability of proliferation and differentiation, morphology, and the cells surface markers. We detected the GDNF mRNA and protein expression level by using real-time polymerase chain reaction (real-time PCR) and enzyme-link immunosorbent assay (ELISA).</p><p><b>RESULTS</b>The UCB-MSCs were successfully isolated and cultured in vitro, and induced it to differentiate into fat cells. FACS results showed that the UCB-MSCs expressed CD90, CD73, and CD105 positively, and CD14, CD34, CD45, CD19, HLA-DR, Stro-1, and CD106 negatively. Real-time PCR and ELISA showed that the expressions of GDNF protein and mRNA were correlated with the copy number of transfected cells: high copy number of transfected cells were associated with high GDNF expression. The biological characterization of UCB-MSCs did not obviously change after sub-cloning with GDNF.</p><p><b>CONCLUSIONS</b>UCB-MSCs was successfully isolated and cultured in vitro. By transfecting UCB-MSCs with GDNF gene-containing lentiviral vectors, the secretion of GDNF protein and mRNA expression level can be controlled by the copy number of transfected cells, and thus make it constantly express GDNF at high level.</p>

Preliminary clinical report of bilateral decompression under microscope via unilateral approach for the treatment of lumbar stenosis / 中华显微外科杂志

@#Objective To report the surgical technique and preliminary clinical results of bilateral decompression under microscope via unilateral approach for the treatment of lumbar stenosis. Methods Sixteen eases of lumbar stenosis were treated in our institute. For the surgical treatment, only one side paraspinous muscle was dissected. The upper and lower margins of the adjacent laminae were drilled, and the underlying ligament flavum was exposed. By changing the direction of the microscopy, the base of the spinous process and the internal side of the contralateral laminae were also drilled off till the lateral recess. Finally, decompression of the spinal canal was achieved by removing the ligament llavum. Results Follow-up ranged from 6 to 47 months. Intermittent claudication was totally relieved in 14 out of 16 cases, and markedly relieved in 2 cases. Back pain was relieved totally in 6 cases, marked improved in 8 cases, not change in 2 cases. Pain was significantly relieved in all 5 cases with sciatica, among them, diseetomy had to be performed in 3 cases. During follow-up, there was no symptom recurrence, and dynamic X ray did not show lumbar in-stability. Conclusion Bilateral decompression under microscope via unilateral approach for the treatment of lumbar stenosis is minimally invasive surgery, the effect of the operation is good. The technique has little in-fluence on spinal stability.

Analysis on del detection of RhD (-) in unrelated blood donors / 中国实验血液学杂志

The study was aimed to analyze Del phenotype of RhD (-) unrelated blood donors. RhD (-) was initially screened by routine serological test and confirmed by indirect antiglobulin test (IAT). Del phenotype was detected by hot-ether absorption-elution test. The results indicated that 106 RhD (-) samples were confirmed out of 38526 donors, and 28 cases were Del detected by hot-ether absorption-elution test. The incidence of Del in RhD (-) samples was 26.41%, The serological phenotypes of Del were Ccee (78.57%), CCee (14.29%) and CcEe (7.14%) respectively. In conclusion, the detection of Del by using hot-ether absorption-elution test is very important for reasonable application of RhD (-) blood. There is difference in Del phenotypes of populations in different regions of China and Japan.