A Novel Concept and 3D Coupler for Robotic Correction of Spinal Deformities: In Vitro Experimental Testing

Current techniques for surgical correction of spinal deformities impart realigning the deviated vertebrae along a rigid rod. Solid rods are a major restricting factor to vertebral manipulation, leading to incomplete, imprecise, and less predictable 3-dimensional (3D) correction. Additionally, forceful manual nonquantifiable maneuvers may result in potential implant failures and increased incidence of complications. We are introducing a machine-operated device for digitized segmental 6 degrees of freedom (6 DOF) correction of individual vertebral deviations.

We manufactured a 3D coupler incorporating multiple self-locking uniaxial joints. The device's precision was tested by comparing targeted vs delivered motions. For functionality testing, we used computed tomography-based 3D-printed vertebral models to verify the device's ability to manipulate the vertebra in each direction of motion.

In all tested motions, the coupler accurately and repeatedly delivered the predicted targeted motions. The device could mobilize 2 vertebral models relative to each other in 4 out of 6 DOF.

The novel 3D coupler can deliver machine-driven, precise, and predictable multiplanar motion; it could manipulate the vertebral model in rotation and translation.

The novel device addresses a crucial unmet need in spinal surgery by offering digital precision, true 6 DOF correction, and supporting robotic execution of surgical actions.