Patients suffering chronic severe pulmonary thromboembolism need Pulmonary Thromboendarterectomy (PTE) to remove the thromb and intima located inside pulmonary artery (PA). During the surgery, a surgeon holds tweezers and a dissector to delicately strip the blockage, but available tools for this surgery are rigid and straight, lacking distal dexterity to access into thin branches of PA. Therefore, this work presents a novel robotized dissector based on concentric push/pull robot (CPPR) structure, enabling entering deep thin branch of tortuous PA. Compared with conventional rigid dissectors, our design characterizes slenderness and dual-segment-bending dexterity. Owing to the hollow and thin-walled structure of the CPPR-based dissector as it has a slender body of 3.5mm in diameter, the central lumen accommodates two channels for irrigation and tip tool, and space for endoscopic camera's signal wire. To provide accurate surgical manipulation, optimization-based kinematics model was established, realizing a 2mm accuracy in positioning the tip tool (60mm length) under open-loop control strategy. As such, with the endoscopic camera, traditional PTE is possible to be upgraded as endoscopic PTE. Basic physic performance of the robotized dissector including stiffness, motion accuracy and maneuverability was evaluated through experiments. Surgery simulation on ex vivo porcine lung also demonstrates its dexterity and notable advantages in PTE.

翻译：慢性重度肺血栓栓塞患者需接受肺动脉血栓内膜剥脱术（PTE）以清除肺动脉（PA）内的血栓及内膜。手术过程中，外科医生需持镊子与剥离器精细剥离阻塞物，但现有手术工具均为刚性直杆结构，缺乏末端灵活性，难以进入肺动脉的细小分支。为此，本研究提出一种基于同心推拉机器人（CPPR）结构的新型机器人化剥离器，能够深入迂曲肺动脉的细小分支。相较于传统刚性剥离器，本设计具有纤细构型与双段弯曲灵活性的特点。基于CPPR的剥离器采用中空薄壁结构，其纤细主体直径仅3.5mm，中央腔体可容纳冲洗通道与末端器械通道，并为内窥镜摄像信号线预留空间。为实现精准手术操作，建立了基于优化的运动学模型，在开环控制策略下实现末端器械（长度60mm）的定位精度达2mm。由此，结合内窥镜摄像系统，传统PTE可升级为内窥镜PTE。通过实验评估了机器人化剥离器的刚度、运动精度与操控性等基础物理性能。离体猪肺手术模拟亦验证了其在PTE中具有的灵活性与显著优势。