Bipolar Coagulation of Occluding Tissue in VP Shunts

描述（由申请人提供）：建议开发一种双极凝固剂，用于电外科凝固或切割粘附的脑组织，这些脑组织阻塞了脑脊液（CSF）流入植入脑室导管的吸入孔。目前，在脑室-腹膜（VP）分流的翻修手术中，单极凝固剂用于清除闭塞组织，以重建导管的功能或允许其安全移除和更换。然而，对于这种应用，双极凝固剂可以更好地控制电流分布，并可能减少严重并发症的可能性。特别是，一些患者的血管损伤和严重的蛛网膜下腔出血与在VP分流翻修手术中使用单极凝固有关。拟议的第一阶段项目将首先建立用户需求规范，然后开发一套具有适合在心室导管内操作的电极配置的双极凝固剂原型。原型将与现有的电外科发电机集成，并插入浸入新鲜蛋清的心室导管。该测试将比较双极原型与目前使用的单极风格关于产生的凝血量，以完成给定的凝血任务。作为最后一步，电灼将应用于羊脑组织，从合适的供应商处获得冷冻，并分析所产生的病变大小，如有必要，将允许对脑组织的蛋清结果进行校正。II期预计将通过动物模型验证双极凝固在该应用中的假设益处。脑室-腹膜分流术是脑积水患者的救命疗法，但随着时间的推移，分流导管通常会堵塞，必须更换以解决这种危及生命的情况。在美国，每年约有23000例脑室导管翻修术中，神经外科医生通常采用说明书外单极烧灼术来降低脑室内出血（IVH）的已知风险。然而，IVH仍然存在风险，最近的病例研究表明，在这种应用中，单极烧灼术与动脉瘤形成相关的风险正在出现。所提出的双极凝固剂是一种更安全的方法，用于脑积水患者进行分流翻修手术时去除闭塞的脑室导管。

DESCRIPTION (provided by applicant): Development of a bipolar coagulator is proposed for electrosurgical coagulation or cutting of adherent brain tissue that is occluding the flow of cerebrospinal fluid (CSF) into the intake holes of an implanted ventricular catheter. Currently, during revision surgery for ventriculoperitoneal (VP) shunts, monopolar coagulators are used to clear the occluding tissue, either to reestablish the function of the catheter or to allow it to be safely removed and replaced. For this application, however, bipolar coagulators offer better control of the distribution of the electrical current and may reduce the likelihood of serious complications. In particular, blood vessel damage and severe subarachnoid hemorrhages in some patients have been associated with the use of monopolar coagulation in VP shunt revision surgery. The proposed Phase I project will first establish a User Requirements Specification and then develop a set of prototypes for bipolar coagulators with electrode configurations suitable for operation inside a ventricular catheter. The prototypes will be integrated with available electro-surgical generators and inserted into ventricular catheters which have been immersed in fresh egg white. The testing will compare the bipolar prototypes with currently-used monopolar stylets with regard to the volume of coagulum produced, in order to accomplish a given coagulation task. As a last step, electrocautery will be applied to sheep brain tissue, obtained frozen from a suitable supplier, and analysis of the resulting lesion sizes will allow correction, if necessary, of the results obtained in egg white for brain tissue. Phase II is expected to verify the hypothesized benefits of bipolar coagulation in this application with animal models. Ventriculoperitoneal shunts are a life-saving treatment for hydrocephalus patients, but shunt catheters commonly become blocked over time and must be replaced to resolve this life-threatening situation. Neurosurgeons routinely employ off-label use of monopolar cautery to reduce the known risk of intraventricular hemorrhage (IVH) during the roughly 23,000 ventricular catheter revisions performed each year in the United States. However, IVH remains a risk, and recent case studies suggest an emerging risk of aneurysm formation associated with monopolar cautery in this application. The proposed bipolar coagulator is intended as a safer means for removal of occluded ventricular catheters from hydrocephalus patients undergoing shunt revision surgery.