This thesis describes the design and development of single-stitch and chain-stitch endoscopic sewing machines for flexible endoscopy as well as devices and methods for tying knots and cutting thread at flexible endoscopy. The work also includes a comparative study of clipping methods for endoscopic haemostasis and a feasibility study of a wireless endoscope that might allow images to be transmitted from sites in the gastrointestinal tract without wires, cables or fibre optic bundles. The development and testing of simple prototypes of such an endoscope are reported. Chapter 1 reviews the surgical instruments and methods used for tissue approximation in general surgery, laparoscopic surgery and flexible endoscopic surgery. The design of existing, conventional sewing machines and the ways in which they form stitches are also considered. In Chapter 2, a comparative study of clipping methods for endoscopic haemostasis is reported. In Chapter 3, the design and development of new single-stitch endoscopic sewing machines are described, together with data on the clinical use of one of these machines. In Chapter 4, studies of ways of improving endoscopic vision during endoscopic sewing and the effects of needle size and the size and shape of the suction cavity are reported. In Chapter 5, the design and development of novel chain-stitch endoscopic sewing machines are reported. These make use of two new catch mechanisms. In Chapter 6, knot tying at flexible endoscopy is considered, and a number of new devices and methods are described and clinical results reported. In Chapter 7, cutting thread at flexible endoscopy is described. Several new endoscopic thread cutting devices and methods together with results are presented. In Chapter 8, a feasibility study of wireless endoscopy is reported. The study includes tests of the concept of wireless endoscopes made using prototypes constructed from miniature CCD cameras and microwave transmitters. Finally, some concluding remarks relating to the work described in this thesis are given
