Research status on finite element analysis of bone drilling / 上海交通大学学报（医学版）

In recent years,the virtual surgery training system with force feedback has provided a new way for young doctors to improve their surgical skills in a safe,efficient and flexible training method.Precise drilling force and realistic hand feeling of manipulation are the cruxes in the virtual surgery training,and the accurate simulation of bone drilling depends on the accurate establishment of drilling force prediction model.The establishment of force prediction model with finite element analysis is the key part in the development of virtual training system.In this paper,the current research status of finite element analysis of bone drilling presented in four aspects:bone model reconstruction,material model,mesh model and prediction of drilling force,especially the construction of bone tissue material model is discussed in detail and several important models are analyzed.This paper presented a relatively complete overview of the approaches commonly used in this research field to promote the establishment of more accurate force prediction models of bone drilling.

Physicochemical properties of calcium phosphate cement incorporated with anti-tumor drugs / 第二军医大学学报

Objective: To study the influence of anti-tumor drug incorporation on the physicochemical properties of calcium phosphate cement(CPC). Methods: Methotrexate (MTX), epirubicin (EPI), hydroxy camptothecin (OH-CPT), and arsenic trioxide (As2O3) were incorporated, each in a proportion of 2%, 5%, and 8%, into the powder-phase CPC. Untreated CPC was taken as control. The setting time, compression strength, and the microstructure of the resultant products were evaluated and tested. Results: Compared with control group, the setting time was significantly prolonged when 2% EPI was incorporated into CPC (P<0.05), and the maximum compression strength was significantly decreased when 5% OH-CPT and 8% MTX, EPI were incorporated into CPC (P<0.05). Electron microscope showed no significant change in the crystal structure after incorporation of the drugs. Conclusion: CPC is an ideal anti-tumor drug delivery material. The changes of physicochemical properties of CPC must be considered when anti-tumor drugs are incorporated into CPC for clinical application.

Physicochemical property and in vitro antitumor activity of arsenic trioxide albumin microspheres / 第二军医大学学报

Objective: To prepare arsenic trioxide (As2 O3) albumin microspheres and to analyze their physicochemical properties and in vitro antitumor activities. Methods: As2 O3 albumin microspheres were prepared by emulsification-heat solidification. Physicochemical and the slow-release properties of the microspheres were identified by the electron microscope, thermal stabilization analysis and dynamic dialysis system in vitro. MTT method was used to evaluate the inhibitory effect of the released fluid on human osteosarcoma cell line U-2 OS cells and human lung adenocarcinoma cell line SPC-A-1 cells. Results: The mean diameter of the microspheres was (156 ± 3.56) μm (ranging 56. 4-256. 7 μm), with the AS2 O3 content being (55.22±11.19)% and t1/2 of release time being 23.34 h. The slowly released fluid showed a significant inhibitory effect on U-2 OS and SPC-A-1 cells. Conclusion: As2 O3 albumin microspheres prepared in the present study have satisfactory physicochemical, slow-releasing, and tumor-inhibition properties.

Clinical characteristics and results of cervical spinal cord injury in the patients with ossification of the posterior longitudinal ligament / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the clinical characteristics and results of cervical spinal cord injury (SCI) in the patients with ossification of the posterior longitudinal ligament (OPLL).</p><p><b>METHODS</b>Nineteen patients with cervical SCI associated with OPLL were retrospectively analyzed. Data collection included: pre- and postoperative neurological function, OPLL-type, MRI signal changes and surgical approaches.</p><p><b>RESULTS</b>Spinal cord associated with OPLL was injured severely by mild trauma. Methylprednisolone sodium succinate was used within 8 h after trauma in 12 cases. Two of them died of complications. The neurological functions were markedly improved in the other 10 cases. Seventeen cases had surgical treatment. The neurological functions (Frankel grade) were improved significantly in the operated patients except for one, who died 27 d after operation.</p><p><b>CONCLUSIONS</b>The patients with OPLL are prone to have severe SCI, which directly associates with the preexisting OPLL-type and hyper-intensity signal change in the spinal cord on MRI. Both of using methylprednisolone sodium succinate administration within 8 h after trauma and surgical decompression may improve the neurological outcomes.</p>

Surgical strategy for severe cervical spine dislocations / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the rate of open reduction and surgical strategy of severe cervical dislocation.</p><p><b>METHODS</b>From March 2001 to March 2006, the data of 92 cases of cervical dislocation over 1/2 were retrospectively studied. Garden Well traction with 1 - 3 kg weight were performed before operation. The patients were performed with diskectomy and reduction with anterior approach initially, for those that can not be reduced, corpectomy were performed and reduction procedures were repeated. The posterior reduction and fixation were followed when reduction can not be reached with anterior approach only. The succeed rate of reduction, rate of tracheotomy were recorded and fusion rate, Frankel score and visual analog scale (VAS) were evaluated.</p><p><b>RESULTS</b>Reduction succeed in 38 cases after diskectomy, 44 after corpectomy and 7 after combined anterior-posterior-anterior procedure. Three cases got incompleteness reduction. Tracheotomy was done in 29 cases. The Frankel score increased 0.5 degree and VAS was 2 averagely at the last follow-up.</p><p><b>CONCLUSIONS</b>The succeed rate of anterior open reduction was 89.2%, and only 10.8% patients needs an additional combined posterior and anterior approach. For patients with completed spinal cord injury with dislocation above C(4), or with dislocation below C(5) but the edema on MRI T2 image are above C(4) level need tracheotomy. The operation be done until respiratory function stable. For patients with completed spinal cord injury with dislocation below C(4) and uncompleted spinal cord injury with dislocation above C(4), the rate of tracheotomy is relatively lower and early operation is recommended.</p>

The study of total spondylectomy in the treatment of cervical spinal tumors / 中华外科杂志

<p><b>OBJECTIVE</b>To study the surgical indications, approaches and the clinical results of the total spondylectomy and instrumentation reconstruction in the treatment of cervical spinal tumor.</p><p><b>METHODS</b>From October 1998 to October 2003, 39 patients with lower cervical bone tumors, including 34 cases with primary tumor and 5 cases with metastatic tumor, were admitted and operated on with total spondylectomy. The patients underwent anteroposterior total spondylectomy including anterior cervical plating, titanium mesh reconstruction and posterior instrumentation based on the location of tumor lesions in the lower cervical spine. One vertebral level total spondylectomy was performed in 29 cases, two level in 7 cases and three level in 3 cases.</p><p><b>RESULTS</b>The postoperative follow-up ranged from 6 months to 4 years. A majority of patients achieved good results postoperatively. Nineteen cases had complete relief of neurological status. One patient died of multiple metastases and systemic failure 24 months later. One case with malignant neurilemmoma developed local recurrence one year postoperatively.</p><p><b>CONCLUSION</b>Anteroposterior total spondylectomy and reconstruction can reduce local recurrence, improve neurological function and increase operation therapeutic effect. Meanwhile, the technique of cervical total spondylectomy carries relatively greater risks and should be more attention to the operation indication.</p>

Investigation of resection and reconstruction procedure of high-sacrum tumors / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the way of resection of high-sacrum tumors and the way and duration of the spinal-pelvic TSRH or ISOLA internal fixation.</p><p><b>METHOD</b>From October 1998 through April 2002, 35 patients with sacral tumor were enrolled in our hospital, including 4 cases in L(5)-S(1), 2 in L(5)-S(2), 4 in S(1), 8 in S(1 - 2), 6 in S(1 - 3), 6 in S(1 - 4), 5 in S(1 - 5). 35 patients were followed by lumbo-pelvic TSRH or ISOLA internal fixation and corresponding chemotherapy and radiotherapy.</p><p><b>RESULTS</b>In the follow-up period of 6 - 42 months, the short-term results were satisfactory with the lumbosacral pain reduced and the neurological function improved in different degrees, however dysuria occurred in 1 case and skin necrobiosis at coccygeal incision occurred in 1 case; two cases experienced cerebrospinal fluid leakage and 1 case experienced postoperative infection and delayed healing, 1 case with chordoma and 2 cases with malignant fibrous histiocytoma recurred 1 year after postoperation, one of these 2 cases with malignant fibrous histiocytoma suffered from lung metastasis and died of system failure 19 months after postoperation. No fractured rod occurred.</p><p><b>CONCLUSION</b>Surgical procedure and postoperative comprehensive treatment have important effects on the prognosis. High-sacral tumor resection and reconstruction are effective means of achieving stabilization, providing significant pain relief and preserving ambulatory capacity.</p>