Intra-operative MRI at 3.0 Tesla: a moveable magnet.

UNLABELLED: This paper presents the development and implementation of an intra-operative magnetic resonance imaging (ioMRI) program using a moveable 3.0 T magnet with a large working aperture. METHODS: A previously established prototype 1.5 T ioMRI program based on a ceiling-mounted moveable magnet was upgraded to 3.0 T. The upgrade included a short, 1.73 m, magnet with a large 70 cm working aperture (IMRIS, Winnipeg, Canada), whole-room radio-frequency shielding, and a fully functional MR-compatible operating room (OR) table. Between January and September 2009, 100 consecutive patients were evaluated at 3.0 T. RESULTS: The ioMRI upgrade maintained a patient-focused environment. When not needed for surgery, the magnet was moved to an adjacent room. A large aperture and streamlined OR table allowed freedom of patient positioning while maintaining access and visibility. Working at 3.0 T enabled application of advanced imaging sequences to the full spectrum of neurosurgical pathology in the ioMRI environment. The use of ioMRI continues to show unsuspected residual tumor in up to 20% of cases. There were no adverse events or technical system failures. CONCLUSION: An ioMRI program based a 3.0 T moveable magnet is feasible. By moving the magnet, the system maintains a patient-focused surgical environment and the ability to share the technology between medical disciplines.

Intra-operative robotics: NeuroArm.

UNLABELLED: This manuscript describes the development and ongoing integration of neuroArm, an image-guided MR-compatible robot. METHODS: A neurosurgical robotics platform was developed, including MR-compatible manipulators, or arms, with seven degrees of freedom, a main system controller, and a human-machine interface. This system was evaluated during pre-clinical trials and subsequent clinical application, combined with intra-operative MRI, at both 1.5 and 3.0 T. RESULTS: An MR-compatible surgical robot was successfully developed and merged with ioMRI at both 1.5 or 3.0 T. Image-guidance accuracy and microsurgical capability were established in pre-clinical trials. Early clinical experience demonstrated feasibility and showed the importance of a master-slave configuration. Surgeon-directed manipulator control improved performance and safety. CONCLUSION: NeuroArm successfully united the precision and accuracy of robotics with the executive decision-making capability of the surgeon.

Advancing neurosurgery with image-guided robotics.

Robotic systems are being introduced into surgery to extend human ability. NeuroArm represents a potential change in the way surgery is performed; this is the first image-guided, MR-compatible surgical robot capable of both microsurgery and stereotaxy. This paper presents the first surgical application of neuroArm in an investigation of microsurgical performance, navigation accuracy, and Phase I clinical studies. To evaluate microsurgical performance, 2 surgeons performed microsurgery (splenectomy, bilateral nephrectomy, and thymectomy) in a rodent model using neuroArm and conventional techniques. Two senior residents served as controls, using the conventional technique only (8 rats were used in each of the 3 treatment groups; the 2 surgeons each treated 4 rats from each group). Total surgery time, blood loss, thermal injury, vascular injury, and animal death due to surgical error were recorded and converted to an overall performance score. All values are reported as the mean +/- SEM when normally distributed and as the median and interquartile range when not. Surgeons were slower using neuroArm (1047 +/- 69 seconds) than with conventional microsurgical techniques (814 +/- 54 seconds; p = 0.019), but overall performance was equal (neuroArm: 1110 +/- 82 seconds; microsurgery: 1075 +/- 136 seconds; p = 0.825). Using microsurgery, the surgeons had overall performance scores equal to those of the control resident surgeons (p = 0.141). To evaluate navigation accuracy, the localization error of neuroArm was compared with an established system. Nanoparticles were implanted at predetermined bilateral targets in a cadaveric model (4 specimens) using image guidance. The mean localization error of neuroArm (4.35 +/- 1.68 mm) proved equal to that of the conventional navigation system (10.4 +/- 2.79 mm; p = 0.104). Using the conventional system, the surgeon was forced to retract the biopsy tool to correct the angle of entry in 2 of 4 trials. To evaluate Phase I clinical integration, the role of neuroArm was progressively increased in 5 neurosurgical procedures. The impacts of neuroArm on operating room (OR) staff, hardware, software, and registration system performance were evaluated. NeuroArm was well received by OR staff and progressively integrated into patient cases, starting with draping in Case 1. In Case 2 and all subsequent cases, the robot was registered. It was used for tumor resection in Cases 3-5. Three incidents involving restrictive cable length, constrictive draping, and reregistration failure were resolved. In Case 5, the neuroArm safety system successfully mitigated a hardware failure. NeuroArm performs as well and as accurately as conventional techniques, with demonstrated safety technology. Clinical integration was well received by OR staff, and successful tumor resection validates the surgical applicability of neuroArm.

An image-guided magnetic resonance-compatible surgical robot.

OBJECTIVE: The past decade has witnessed the increasing application of robotics in surgery, yet there is no existing system that combines stereotaxy and microsurgery in an imaging environment. To fulfill this niche, we have designed and manufactured an image-guided robotic system that is compatible with magnetic resonance imaging. METHODS: The system conveys the sight, touch, and sound of surgery to an operator seated at a remote workstation. Motion scaling, tremor filtering, and precision robotics allow surgeons to rapidly attain technical proficiency while working at a spatial resolution of 50 to 100 microm instead of a few millimeters. This system has the potential to shift surgery from the organ toward the cellular level. RESULTS: By integrating the robot with images obtained during the procedure, the effects of surgery on both the lesion and brain are immediately revealed. CONCLUSION: We are providing technology to advance and transform surgery with the potential to improve patient outcome.