Investigating the effectiveness of using augmented reality headset in spinal facet joint injections on human cadaver model

Introduction Spinal pain is an important public health issue leading to a substantial increase in treatment costs, loss of productivity, disability, and drug use. Spinal pain can affect people of all ages, from adolescents to the elderly; and the lifetime prevalence ranges from 50% to 80%. Facet syndrome, which develops due to degeneration of facet joints, can be considered one of the most common causes of the spinal pain. Studies have found that 15-45% of low back pain, 54-67% of neck pains, and an average of 48% of back pain are associated with facet syndrome. The most common method used in the diagnosis and treatment of facet syndrome worldwide is facet joint injections. Facet joint injections are often performed with c-arm fluoroscopy in clinical practice. The c-arm fluoroscopy device emits X-rays, and radiation exposure occurs in use. In addition, the process is performed by looking at a separate screen on a two-dimensional image. Operating by looking at the two-dimensional image on the screen requires experience and is not easy, and it may shift the doctor's focus. Augmented reality technology, interacting with the real world, can reflect three-dimensional images created in the computer environment to the user's eye. Our study aims to perform facet joint injections with augmented reality headset compared to c-arm fluoroscopy. Materials and Methods We used five human cadavers. After the cadavers were marked with unique markers for the procedure, spinal CT was performed. CT data were processed using open-source programs called 3D Slicer and Blender, and a 3D model of the cadaver spine was created. A separate program was developed for each injection using the Unity and Vuforia Engine SDK image target system. These programs were run on the Microsoft HoloLens 2 augmented reality headset. Next, in the experimental group, a total of 72 needles (20 G, Spinocan, Braun) at 18 levels from C7-T1 to L5-S1 for two cadavers and 36 needles for three cadavers at six levels from T12-L1 to L5-S1 were placed. After the needles were placed, no medication was injected, and we performed a spinal CT to test the accuracy of the needle placements. After the needles were removed from the cadavers, facet joint injections were performed using the c-arm fluoroscopy in the control group, and then we performed a spinal CT. Results Neuroradiologists independently evaluated each needle placements in the experimental and control groups based on the following scoring: unsuccessful, successful, and excellent. The independent sample t-test indicated that the success rate in 108 injections in the experimental group (X̄ = 2.25, SS = 0.68) was slightly higher compared to the 108 injections in the control group (X̄ = 2.12, SS = 0.66) but there was no statistically significant difference among two groups, t(214) = 1.51, p = .13. Conclusion Compared to the c-arm fluoroscopy, the facet joint injections performed with the augmented reality headset provided no statistically significant differences in the success and safety rate in human cadavers. The study can act as a proof of concept to show the feasibility of using AR in facet joint injections. Furthermore, the procedure can be facilitated by moving it from a two-dimensional image to a three-dimensional image. Benefiting from these advantages, AR headsets can effectively improve the quality of the procedure, reduce the dependence on the experience of surgeons by eliminating the problem of focus switching, and reduce the intensity of the radiation exposure of the patient and healthcare personnel.