Robotic Replica of a Human Spine Uses Soft Magnetic Sensor Array to Forecast Intervertebral Loads and Posture after Surgery

Abstract

Cervical disc implants are conventional surgical treatments for patients with degenerative disc disease, such as cervical myelopathy and radiculopathy. However, the surgeon still must determine the candidacy of cervical disc implants mainly from the findings of diagnostic imaging studies, which can sometimes lead to complications and implant failure. To help address these problems, a new approach was developed to enable surgeons to preview the post-operative effects of an artificial disc implant in a patient-specific fashion prior to surgery. To that end, a robotic replica of a person’s spine was 3D printed, modified to include an artificial disc implant, and outfitted with a soft magnetic sensor array. The aims of this study are threefold: first, to evaluate the potential of a soft magnetic sensor array to detect the location and amplitude of applied loads; second, to use the soft magnetic sensor array in a 3D printed human spine replica to distinguish between five different robotically actuated postures; and third, to compare the efficacy of four different machine learning algorithms to classify the loads, amplitudes, and postures obtained from the first and second aims. Benchtop experiments showed that the soft magnetic sensor array was capable of precisely detecting the location and amplitude of forces, which were successfully classified by four different machine learning algorithms that were compared for their capabilities: Support Vector Machine (SVM), K-Nearest Neighbor (KNN), Random Forest (RF), and Artificial Neural Network (ANN). In particular, the RF and ANN algorithms were able to classify locations of loads applied 3.25 mm apart with 98.39% ± 1.50% and 98.05% ± 1.56% accuracies, respectively. Furthermore, the ANN had an accuracy of 94.46% ± 2.84% to classify the location that a 10 g load was applied. The artificial disc-implanted spine replica was subjected to flexion and extension by a robotic arm. Five different postures of the spine were successfully classified with 100% ± 0.0% accuracy with the ANN using the soft magnetic sensor array. All results indicated that the magnetic sensor array has promising potential to generate data prior to invasive surgeries that could be utilized to preoperatively assess the suitability of a particular intervention for specific patients and to potentially assist the postoperative care of people with cervical disc implants.

A Review on Magnetic Smart Skin as Human–Machine Interfaces

“…In 2022, Lin et al developed a new approach through magnetic films to enable surgeons to preview the post-operative effects of an artificial disc implant in a patient-specific fashion prior to surgery. [4] Figure 3. Three different structures of magnetoelastomer: a) Magnetic film.…”

“…tactile perception, including 3D position and motion tracking and human−machine interactions. [4] Magnetoelastomers provide a novel path forward for noncontact HMI technology. Nevertheless, magnetoelastomers still require magnetic sensors in order to perceive, which will bring many limitations to the applications.…”

“…developed a new approach through magnetic films to enable surgeons to preview the post‐operative effects of an artificial disc implant in a patient‐specific fashion prior to surgery. [ 4 ]…”

“…Lin et al, combined with the magnetoelastomers and the graphene oxide and carbon nanotubes, developed a flexible proximity sensor for touchless tactile perception, including 3D position and motion tracking and human−machine interactions. [ 4 ]…”

“…There has been a meteoric rise in the popularity of electronic wearables over the past two decades. [1][2][3][4] These electronic devices have a broad variety of uses, some of which include monitoring the health state of humans, [1,2,[5][6][7] tracking the movement and activities of human beings and functioning as a human-to-machine DOI: 10.1002/aelm.202300677 interface (HMI). [6][7] In the not-toodistant future, electronic gadgets will be unnoticeable and will build a connection that is seamless between the analog and digital worlds.…”