CIGuide: in situ augmented reality laser guidance

Abstract

Purpose A robotic intraoperative laser guidance system with hybrid optic-magnetic tracking for skull base surgery is presented. It provides in situ augmented reality guidance for microscopic interventions at the lateral skull base with minimal mental and workload overhead on surgeons working without a monitor and dedicated pointing tools. Methods Three components were developed: a registration tool (Rhinospider), a hybrid magneto-optic-tracked robotic feedback control scheme and a modified robotic end-effector. Rhinospider optimizes registration of patient and preoperative CT data by excluding user errors in fiducial localization with magnetic tracking. The hybrid controller uses an integrated microscope HD camera for robotic control with a guidance beam shining on a dual plate setup avoiding magnetic field distortions. A robotic needle insertion platform (iSYS Medizintechnik GmbH, Austria) was modified to position a laser beam with high precision in a surgical scene compatible to microscopic surgery. Results System accuracy was evaluated quantitatively at various target positions on a phantom. The accuracy found is 1.2 mm ± 0.5 mm. Errors are primarily due to magnetic tracking. This application accuracy seems suitable for most surgical procedures in the lateral skull base. The system was evaluated quantitatively during a mastoidectomy of an anatomic head specimen and was judged useful by the surgeon. Conclusion A hybrid robotic laser guidance system with direct visual feedback is proposed for navigated drilling and intraoperative structure localization. The system provides visual cues directly on/in the patient anatomy, reducing the standard limitations of AR visualizations like depth perception. The custom- built end-effector for the iSYS robot is transparent to using surgical microscopes and compatible with magnetic tracking. The cadaver experiment showed that guidance was accurate and that the end-effector is unobtrusive. This laser guidance has potential to aid the surgeon in finding the optimal mastoidectomy trajectory in more difficult interventions.

The endonasal patient reference tracker: a novel solution for accurate noninvasive electromagnetic neuronavigation

“…Recently, the same group described a nasopharyngeal registration tool for lateral skull base surgery in an experimental setup. 16 This so-called Rhinospider was inserted into the nasopharynx prior to preoperative imaging, serv-ing as a fiducial for imaging and tracking until the end of surgery.…”

Novel microscope-based visual display and nasopharyngeal registration for auditory brainstem implantation: a feasibility study in an ex vivo model

“…An early concept of this scheme was introduced for lateral skull base surgery and yielded submillimetric accuracy in a phantom setup [ 30 ]. We extended this scheme with a novel device [ 12 ].…”

Visual guidance for auditory brainstem implantation with modular software design

“…First is using markers such as bone-implanted screws localized manually by a surgical probe. Second employs spherical markers with installed magnetic sensors placed inside the nasal cavity prior to preoperative imaging [5]. Third approach is semi-automatic by combining both the first and second approach.…”