A High-Load Stress Sensor for Scoliosis Surgery Application

Abstract

The design of a stress sensor for a scoliosis surgery application is presented. Designed specifically for detecting forces and moments placed on spinal hooks and screws used in scoliosis correction, the sensor is less 2mm in the largest dimension and less than 0.5mm in thickness. The operative range is approximately 1000MPa in shear and normal stress directions. Preliminary FEA simulation of a piezoresistive sensor incorporating these design constraints demonstrates that different output signals are produced as the sensor is subjected to shear and normal stresses. When the separate signal patterns from several sensors are combined, the hooks and screws will be able to resolve forces and moments in three dimensions.

A packaging solution utilizing adhesive-filled TSVs and flip–chip methods

“…The specific application for the packaging techniques described in this paper is the measurement of 3D forces and moments applied to the spine during scoliosis correction surgery. This six-axis load characterization, as discussed in previous work [25][26][27], can improve the accuracy of presurgical planning models and can also provide quantified feedback to surgeons to compliment their physical dexterity. The proposed six-axis load measurement device is a wireless MEMS sensor array retrofit onto existing spinal screws.…”