Flexible distal tip made of nitinol (NiTi) for a steerable endoscopic camera system

In laparoscopic surgery the endoscopic camera is mounted to the end of an integrated rod lens system and, therefore, the whole endoscopic camera system is rigid. To obtain a better overview of the operation area, different lens systems with certain angles of view (0, 32, 45 and 70 degrees) are used. To avoid changing the camera system during all operation, a flexible distal end for a single chip camera was built. Therefore an exchange of cameras during an operation is no longer necessary. The flexible tip is made of a superelastic Nitinol (NiTi) tube and can be angled up to 900 inside the human body. The outer diameter of the superelastic tube is 10.5 mm and. as there are no tubes of that size commercially available on the market, it was manufactured using NiTi sheet material. To enable angles of up to 900, new structures were cut into the NiTi tube with a Nd-YAG laser. To reduce the induced tension at the bending zones, shape optimization was performed using the ABAQUS FEM software. This allowed a reduction in tension of about 40% for the optimized structure. Consequently, bending cycles of up to 10(5) are now possible. The angles are adjusted with the thumb on the proximal end of the endoscope and a locking device at this end enables the angle to be kept at any position for any time. (C) 1999 Elsevier Science S.A. All rights reserved.