Three-dimensional analysis of puncture needle path through safety triangle approach PLD and design of puncture positioning guide plate.

OBJECTIVE: In this study, the three-dimensional relationship between the optimal puncture needle path and the lumbar spinous process was discussed using digital technology. Additionally, the positioning guide plate was designed and 3D printed in order to simulate the surgical puncture of specimens. This plate served as an important reference for the preoperative simulation and clinical application of percutaneous laser decompression (PLD). METHOD: The CT data were imported into the Mimics program, the 3D model was rebuilt, the ideal puncture line N and the associated central axis M were developed, and the required data were measured. All of these steps were completed. A total of five adult specimens were chosen for CT scanning; the data were imported into the Mimics program; positioning guide plates were generated and 3D printed; a simulated surgical puncture of the specimens was carried out; an X-ray inspection was carried out; and an analysis of the puncture accuracy was carried out. RESULTS: (1) The angle between line N and line M was 42°~55°, and the angles between the line M and 3D plane were 1°~2°, 5°~12°, and 78°~84°, respectively; (2) As the level of the lumbar intervertebral disc decreases, the distance from point to line and point to surface changes regularly; (3) The positioning guide was designed with the end of the lumbar spinous process and the posterior superior iliac spine on both sides as supporting points. (4) Five specimens were punctured 40 times by using the guide to simulate surgical puncture, and the success rate was 97.5%. CONCLUSION: By analyzing the three-dimensional relationship between the optimal puncture needle path and the lumbar spinous process, the guide plate was designed to simulate surgical puncture, and the individualized safety positioning of percutaneous puncture was obtained.

Improve the reliability of the ion source beam extraction by adopting a solid-state suppress electron power supply.

A solid-state suppress grid power supply (SGPS) is developed to be applied to the 5 MW level neutral beam injection (NBI) on HL-2M Tokamak. The power supply consists of ten modules in series, with an index of 560 V/40 A. Each of the modules is composed of an isolated transformer, rectifier, filter tank, insulated gate bipolar transistor switch, gate-drive circuit, free-wheeling diode, and so forth. An embedded system STM32F103 is used for controlling and protecting the SGPS. Meanwhile, the transient output capacity of the SGPS is tested. The effect of the output voltage of the SGPS on the extracted beam current is studied. The experimental results show that there is a turning point in the relationship between the suppress voltage and the extracted beam current. When the rate of the absolute value of the suppress voltage and the gradient voltage is more than 2.5%, the efficiency of the extracted beam of the ion source can be improved. Compared with the previous types of equipment of the NBI system, the extracted beam success rate of the new SGPS increased by more than 20%. The SGPS meets the requirements of the NBI system.

Downregulation of WIF-1 by hypermethylation in astrocytomas.

Wnt inhibitory factor-1 (WIF-1) acts as a Wnt antagonist and tumor suppressor, but hypermethylation of WIF-1 gene promoter and low expression of WIF-1 activate Wnt signaling aberrantly and induce the development of several human tumors. By using RT-PCR, immunohistochemistry and methylation-specific PCR, we analyzed the expression and methylation of WIF-1 in 4 normal brain tissues, 35 freshly resected astrocytoma tissues and 4 glioblastoma-derived cell lines. Significant downregulation of WIF-1 mRNA and protein expression levels was observed in astrocytoma tissues compared with normal brain tissues. Significant association between WIF-1 downregulation and pathological grade of astrocytomas was found. WIF-1 gene aberrant methylation was observed in 19 of 35 (54.29%) tumor samples. The promoter methylation tumors showed low WIF-1 protein and mRNA expression, whereas the promoter unmethylation tumors displayed high protein and mRNA expression levels. Moreover, complete absence of WIF-1 mRNA expression was observed in four cell lines, whereas treatment with demethylating agent, 5-aza-2'-deoxycytidine, restored WIF-1 expression. Our results suggested that the WIF-1 gene is frequently silenced in astrocytoma by aberrant promoter methylation. This may be an important mechanism in astrocytoma carcinogenesis.

[Effect of epidural drainage and dural tenting suture on epidural hematoma in 145 cases of craniotomy].

OBJECTIVE: To evaluate the efficacy of dural tenting suture and epidural drainage in craniotomy. METHODS: In 145 cases of intracranial lesions, dural tenting suture and epidural drainage were performed to prevent epidural hematoma. RESULTS: Postoperative computed tomography (CT) showed no epidural hematoma required surgery in both groups. CONCLUSION: Both dural tenting suture and epidural drainage are effective in preventing epidural hematoma. Hemostasis is the key step. Dural tenting suture without epidural drainage relieves psychological stress. It decreases the risk of intracranial infection and avoids some unusual complications.

[Microsurgery techniques for insular glioma].

OBJECTIVE: To explore the microsurgical techniques for insular glioma without damaging its surrounding normal structures. METHODS: We retrospectively analyzed 54 patients with insular gliomas who underwent microsurgical operation by trans-syvian fissure approach between May, 2003 and August, 2008 in Xiangya Hospital. We discussed the techniques in the operation and summarized how to protect the key blood vessels, distinguish and protect the surrounding normal structures. RESULTS: There were 36 complete removals,14 secondary complete removals, and 4 partial removals.Six patients had complications after the craniotomy who had temporal speech disorder (aphasia mostly began to recover about 10 days after the craniotomy),4 patients had opposite side paralysis worsening (3 recovered normally and 1 improved after 6 months),4 had light paralysis, and another 3 had paralysis and speech disorder. CONCLUSION: The microsurgery by means of trans-syvian fissure approach can well expose the anatomical relation between tumor and its surrounding structures,so that we can remove the tumor and protect the surrounding normal tissues as much as we can.