可配合連續縫合之微創手術用打結器之研發

Abstract

在微創手術中，體內打結變得困難而耗時。體內打結可分為三個步驟：纏繞、穿結和拉結，每一個步驟都有其困難。為了改善體內打結，前人提出各種打結器，但都只有改善了部分問題。其中轉盤打結器藉由傘齒輪驅動轉盤，可在體內同時完成纏繞與穿結，最能降低打結之困難度與時間。並可以通用各式縫合針，不會限制其打結位置。然而由於縫線一端固定在轉盤上，此打結器無法配合連續縫合。

本文在此提出可使用傳統各式縫合針且可配合連續縫合之打結器設計。不同於轉盤打結器的齒輪驅動，本設計採用皮帶繩搭配撓性轉盤的打結機構。利用此機構，本設計除了有體內打結功能外，還使轉盤具有在體內自由夾取縫線的功能。透過這兩個功能，本設計可以在切口一端完成一個外科結後，移到切口之另一端重新夾取新的固定端縫線，進行第二次的打結以完成連續縫合。在設計打結器中，藉由力學關係的分析與有限元素法的模擬，本文提出轉盤槽夾尺寸的設計準則。其中發現撓性轉盤的剛性與皮帶繩的摩擦係數是關鍵的設計因素。

打結器中除了皮帶繩與彈簧以外的元件皆以快速成型法製造。由於製造精度的限制，原型以原設計尺寸兩倍的大小製作。組裝完成後，打結器已可以進行打結之操作。且在一開放式打結平台上，成功地以打結器原型配合輔助夾爪進行連續縫合，並驗證了本設計之可行性。

In minimally invasive surgery (MIS), intracorporeal suture and knot-tying is very complex and time-consuming. A knot-tying device with turntable disk has been proposed previously. This device could perform winding and passing suture simultaneously inside body by simply turning the disk through a bevel gear, which significantly reduced the difficulty. However due to one end of suture was fixed to the disk, it was difficult to use this device for continuous suture.

Here a new knot-tying device is proposed based on previous turntable-disk mechanism by using a belt to drive the flexible disk with a slot inside. By controlling the belt tension, the flexible disk can be rotated and clamping the suture. This feature enables the proposed device to tie knot in different locations, i.e. continuous suture. The key dimensions in the proposed device are designed through analytical and finite-element method. It is fund that rigidity of the flexible disk and frictional coefficient of belt are two key factors.

An enlarged prototype of the proposed device is made by rapid- prototyping due to precision limit of RP process. Knot-tying and continuous suture are demonstrated by this prototype successfully, which verifies the feasibility of the proposed design