Augmented Bridge Spinal Fixation: A New Concept for Addressing Pedicle Screw Pullout via a Steerable Drilling Robot and Flexible Pedicle Screws

TL;DR

This paper introduces Augmented Bridge Spinal Fixation (AB-SF), a novel technique combining steerable drilling and flexible screws to improve spinal fixation stability and prevent screw pullout.

Contribution

It presents a new concept integrating a steerable drilling robot and flexible screws with cement augmentation for enhanced spinal fixation.

Findings

Successful drilling of J-shape tunnels in vertebral phantom

Feasibility demonstrated for screw implantation and cement augmentation

Potential for improved fixation stability and reduced screw loosening

Abstract

To address the screw loosening and pullout limitations of rigid pedicle screws in spinal fixation procedures, and to leverage our recently developed Concentric Tube Steerable Drilling Robot (CT-SDR) and Flexible Pedicle Screw (FPS), in this paper, we introduce the concept of Augmented Bridge Spinal Fixation (AB-SF). In this concept, two connecting J-shape tunnels are first drilled through pedicles of vertebra using the CT-SDR. Next, two FPSs are passed through this tunnel and bone cement is then injected through the cannulated region of the FPS to form an augmented bridge between two pedicles and reinforce strength of the fixated spine. To experimentally analyze and study the feasibility of AB-SF technique, we first used our robotic system (i.e., a CT-SDR integrated with a robotic arm) to create two different fixation scenarios in which two J-shape tunnels, forming a bridge, were drilled at different depth of a vertebral phantom. Next, we implanted two FPSs within the drilled tunnels and then successfully simulated the bone cement augmentation process.