# Augmented Reality: Mapping Methods and Tools for Enhancing the Human Role in Healthcare HMI
## 3 Results
### Intraoperative Solution
#### 3.3.2 Spine Surgery  
The spinal cord, emerging spinal nerves, and respective blood vessels are more likely to be injured during orthopedic surgery interventions, given their proximity to the bones of the spine. For this reason, many researchers have developed ARSN systems for instrumentation of the pedicle screw, whose misplacement can cause severe vascular or neurological injury. In a clinical study, [PERSON] et al. [63] evaluated, for the first time, the accuracy of pedicle screw placement using an ARSN system. A hybrid operating room was equipped with the ARSN system, a motorized flat-sensing C-arm with 2D/3D intraoperative capabilities, a surgical table, a noninvasive marker-based patient motion tracking system, and an integrated optical camera for AR-based navigation. For each screw, the insertion was planned, and the proper track for instrument navigation was displayed in AR by rotation of the C-arm. This clinical trial was the first prospective human study in a hybrid operating room equipped with the ARSN system for the placement of 253 screws in twenty consecutive patients, among which only three required intraoperative revision. In a subsequent cadaver study [79], the same ARSN system was used by two neuro-surgeons for the insertion of 66 Jamshidi needles and 18 cannulated pedicle screws into the thoracolumbar spine. The distance between the actual needle tip position and the corresponding planned path, as well as the angles between the needle and the desired path, were measured to assess the technical accuracy of the ARSN system. The obtained results indicate that the ARSN system can be used without the use of any fluoroscopy or X-ray imaging during the procedure for percutaneous pedicle screw placement. The screw placement accuracy and clinical aspects of the ARSN system were compared with those achievable using the freehand (FH) technique in twenty patients [54]. The same surgeon performed the surgical procedures both with ARSN and FH, resulting in greater accuracy of the first compared to the latter. [PERSON] et al. [53] presented a workflow to introduce, in clinical practice, the ARSN system described by [PERSON] et al. [63] installed in a hybrid operating room for visualization of the anatomy and instrument guidance during pedicle screw placement. The workflow encompasses all surgical processes from pedicle screw path planning for instrument guidance during surgery to their placement and spinal fixation, to wound closure and intraoperative verification of treatment results. It also considers imaging time and automated 3D model creation. Special attention was paid to the radiation exposure of the staff so that the need for lead aprons was avoided [52]. A study with twenty cases requiring the placement of pedicle screws (13/20 scoliosis) validated the navigation workflow. The results show that the ARSN system could decrease the risk of complications and surgical revision and minimizes staff radiation exposure, demonstrating how it can be integrated into the clinical routine without invalidating it, as only 8% of the total time was used for intraoperative imaging and preparation for surgical navigation. [PERSON] et al. [48] evaluated the safety, accuracy, technical feasibility, and patient exposure to radiation of a new navigation system that integrates artificial intelligence (AI) and AR, during percutaneous vertebplasty of patients with vertebral compression fractures (VCFs). Four cameras were integrated into the flat panel detector of a standard C-arm fluoroscopy machine for AR navigation. Spinal segmentation and optimal trajectory planning were automatically performed by an integrated AI software, that also suggested a detector position for the initial targeting. The planned \"virtual\" trajectory is then superimposed on the \"real world\" camera inputs, and the merged information is displayed on a 2D monitor without the need for fluoroscopy.