Bipolar Coagulation of Occluding Tissue in VP Shunts

描述(申请人提供)：开发一种双极电凝器，用于电外科凝固或切割粘连的脑组织，阻断脑脊液(CSF)流入植入的脑室导管的进气孔。目前，在脑室-腹膜分流术的翻修手术中，使用单极凝血器清除闭塞组织，以重建导管的功能或安全地取出和更换导管。然而，对于这种应用，双极电凝器可以更好地控制电流的分布，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VP分流手术中单极凝血的使用有关。拟议的第一阶段项目将首先建立用户需求规范，然后开发一套双极凝血器的原型，其电极配置适合在脑室导管内操作。原型将与可用的电子外科发电机集成在一起，并插入已浸泡在新鲜蛋清中的脑室导管。测试将比较双极原型和目前使用的单极针头产生的凝固物的体积，以完成给定的凝血任务。作为最后一步，电灼术将应用于从合适供应商获得的冷冻绵羊脑组织，如果有必要，对所产生的病变大小的分析将允许对脑组织蛋清中获得的结果进行修正。第二阶段预计将通过动物模型验证双极凝固在这一应用中的假设益处。脑室-腹膜分流术对脑积水患者来说是一种挽救生命的治疗方法，但分流导管通常会随着时间的推移而堵塞，必须更换才能解决这种危及生命的情况。在美国每年大约进行23,000次脑室导管修订期间，神经外科医生经常使用标签外的单极电灼术来降低已知的脑室出血(IVH)风险。然而，IVH仍然是一种风险，最近的案例研究表明，在这种应用中，与单极烧灼相关的动脉瘤形成的风险正在显现。对于接受分流手术的脑积水患者，建议的双极电凝器被认为是一种更安全的方法来移除闭塞的脑室导管。

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.