Introduction: In its infancy, lead placement in deep brain stimulation required a cumbersome frame. Then frameless systems emerged, but bone fiducial placement was still necessary. Our study compares the accuracy and efficiency of frameless, fiducial-less, O-arm auto-registration with standard Nexframe O-arm registration using bone fiducials. Pitfalls and pearls of this new technique are outlined.

Methods: Patients underwent deep brain stimulation surgery using Nexframe technology at Richmond’s VA Medical Center and VCU-Health. Surgical navigation registration was performed with a Medtronic Stealth station and an O-arm. Patients either underwent fiducial-less registration or standard fiducial registration. Intraoperative imaging was used to determine vector and radial error by using algorithms to extract the implants from the unreconstructed O-arm data to more precisely localize the implants and compare them with the preoperative plans within the same image space. Operative times, radiation dose, and number of passes were also collected and compared.

Results: At the time of this abstract, 24 of a planned 40 patients have undergone placement of 32 leads utilizing fiducial-less registration. These are compared with 39 patients who have had 61 leads implanted utilizing fiducial based registration. In comparing the two groups, total operative time in the fiducial-less group was reduced by 37.6 and 25.1 minutes at VCU-Health and the VA Medical Center respectively. Also, the number of microelectrode passes between the 2 groups was not different. Vector and radial error will be reported.

Conclusions: Based on preliminary data, we have changed our practice to an exclusively fiducial-less approach. Despite the learning curve, we have been able to reduce operative time with this procedure without an increased number of microelectrode passes. The new procedure also saves the patients and surgeons from multiple incisions for the placement of bone fiducials.

Patient Care: Frameless, fiducial-less O-arm registration saves the patient multiple incisions for bone fiducial placement, and it also can decrease the time the patient is in the operating room.

Learning Objectives: By the conclusion of this session, participants should be able to: Understand the techniques involved in placing deep brain stimulator leads using a frameless fiducial-less system. Discuss the difference between fiducial based Oarm registration and fiducial-less O-arm registration. Compare the accuracy of different methods of deep brain stimulator lead placement.

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