Development and Preclinical Trials of a Novel Steerable Cannula for 360 degrees Arthroscopic Capsular Release in Minimally Invasive Surgery

Abstract

Many of the surgical devices for minimally invasive surgery have struggled to navigate in tight spaces and to safely address to surgical sites. This research demonstrates a scalable steerable cannula for 360 degrees arthroscopic capsular release (ACR) of the glenohumeral joint. The steerable cannula mainly consists of the pre-curved inner tube of nitinol, the straight outer tube of stainless steel, and the controller part. Using anisotropic patterns and heat treatment, the inner tube has a high degree of curvature. The mechanism controls the distal end with the two degrees of freedom. The inner tube can be translated and rotated relative to the outer tube. The steerable cannula was designed to avoid the axillary nerve under the inferior glenoid to minimize the risk of iatrogenic injury while keeping flexed to match the bony curvature of the glenohumeral joint. The cylindrical cannula can fit various surgical tools and can be sterilized after use. In porcine shoulder test and workspace analysis, the proposed cannula addressed the inferior glenoid that is not reachable by the conventional rigid cannula. Thus, the proposed mechanism can navigate through the narrow and curved anatomical space of the glenoid cavity and reduce the unreachable area for ACR.