Minimal access nerve surgery and interventional magnetic resonance imaging

Develop and assess the utility of novel minimal access techniques including percutaneous open-configuration interventional magnetic resonance imaging (iMRI), open surgery using open or closed/cylindrical iMRI systems, and minimal access open surgery with electromyographic guidance in a standard operating room.

For more than 2500 percutaneous open iMRI procedures, 25 incisional surgery open iMRI cases, 3 incisional surgery closed/cylindrical iMRI cases, 25 computed tomography-guided percutaneous procedures, and more than 1000 minimal access incisional surgery cases in the standard operating room with electromyographic guidance, cycle time for intraoperative data collection and numbers of guidance events per case were assessed.

Cycle time varied greatly. The minimum was for open surgery in the standard operating room with direct nerve stimulation for electromyography, requiring 10 to 15 seconds, which was applicable for dozens of assessments during the surgery and had negligible effects on total surgical time. Percutaneous procedures in the open iMRI environment allowed for 20 or 30 imaging events during a procedure, with cycle times of between 10 and 20 seconds. Incisional surgery in the open iMRI system had a cycle time of about 1 to 5 minutes for "in-magnet" procedures and about 5 to 10 minutes for "magnet-adjacent" procedures. Incisional surgery in closed/cylindrical iMRI procedures had a cycle time of 45 to 60 minutes, and the technique proved awkward to use more than once or twice per surgical case.

Percutaneous open-configuration iMRI provides clear benefits over computed tomography or ultrasound. Minimal access surgery and incisional open-configuration iMRI are useful and effective in some situations. Closed/cylindrical iMRI systems pose challenges for patient safety, add greatly to surgical time, and provide limited useful intraoperative benefits.