Electromagnetic Navigation in Minimally Invasive Spine Surgery: Results of a Cadaveric Study to Evaluate Percutaneous Pedicle Screw Insertion

Abstract

BackgroundTh is cadaveric study compared effi cacy and safety of an electromagnetic (EM) guidance system versus conventional fl uoroscopy for percutaneous pedicle screw fi xation. As percutaneous pedicle screw fi xation becomes increasingly common in spinal surgery, intraoperative imaging systems that maximize effi ciency while minimizing radiation exposure and inaccurate trajectories will be progressively more important. Published studies have validated the safety of percutaneous screw fi xation using conventional fl uoroscopic guidance and frameless optical stereotaxy, though EM guidance systems have not been evaluated for percutaneous placement in the lumbosacral spine. Th e aim of the study was to evaluate the clinical applicability of an EM system for minimally invasive spine fusion in the lumbosacral spine. MethodsFive human cadaveric specimens underwent bilateral lumbosacral percutaneous screw fi xation from L1 to S1 using conventional anteroposterior (AP) and lateral fl uoroscopic techniques on one side and 2-dimesional (2D) EM guidance on each matching side. Intraoperative effi ciency was evaluated, and pedicle, vertebral, and critical breach rates were assessed on postoperative computed tomography (CT). ResultsOverall mean fl uoroscopy time per screw was 58.9 ± 44.7 seconds for conventional fl uoroscopy compared to 27.4 ± 13.5 seconds for electromagnetic guidance (P = .0003). Pedicle, vertebral, and critical breach rates for the L1-S1 were 32.1%, 10.7%, and 25.0% for conventional fl uoroscopy and 42.8%, 10.7%, and 14.1% for electromagnetic guidance (diff erence not statistically signifi cant [ns]). In comparing critical breaches in the lumbar spine (L1-L5), there was a signifi cant diff erence between 2-D EM guidance (0) and CF guidance (6) (P = .02). ConclusionsTwo-dimensional EM navigation provides a modality for lumbosacral percutaneous pedicle screw fi xation that is more effi cient and safer than conventional fl uoroscopy. Th is data provides a foundation for further clinical trials of this technology. Level of EvidenceLevel 5 -Bench Research Key Words: Minimally invasive spine fusion, percutaneous pedicle screw fi xation, electromagnetic guidance.

Percutaneous laser discectomy guided with stereotactic computer‐assisted surgical navigation

“…Today computer-assisted frameless navigation is a newly evolving technology that has been further adapted from intracranial surgery for use in minimally invasive spinal procedures [30,31,33,41]. Minimally invasive surgery combines traditional concepts of spine surgery with specialized imaging performed through small surgical incisions or trocars.…”

“…It relies on detecting the EM field at the receiver relative to the transmitter. It responds to variations within the detected EM field caused by movement of an instrument or the patient [31]. The system consists of an anatomically placed reference transmitter percutaneously affixed to the spinous process by a 2-mm bone pin and a receiver placed on the surgical instrument, or in this case integrated with the Nav Trocar [31][32][33].…”

“…It responds to variations within the detected EM field caused by movement of an instrument or the patient [31]. The system consists of an anatomically placed reference transmitter percutaneously affixed to the spinous process by a 2-mm bone pin and a receiver placed on the surgical instrument, or in this case integrated with the Nav Trocar [31][32][33]. The sensors provide positional (X, Y, Z) information, which correlates the movement of the Nav Trocar to the preoperative CT images displayed on the interactive monitor [32].…”

“…In specimen 2, L1-L6 discs received incremental laser irradiation. Other than a few scout or control shots to correlate accuracy, the Nav Trocar can be guided without the need of repetitive C-arm fluoroscopy, minimizing exposure to intraoperative scatter of ionizing radiation [31,33]. Postoperative MR imaging was undertaken for comparison with preoperative MR images.…”

Exposition des chirurgiens et des patients aux rayonnements ionisants pendant les procédures d’ostéosynthèse rachidienne postérieure percutanée : étude prospective de 100 patients

“…Elle dépend de divers facteurs : l'indice de masse corporelle (IMC) du patient, le niveau d'instrumentation, l'expérience du chirurgien et les caractéristiques techniques et réglages de l'arceau de bloc (C-arm) pendant la chirurgie. Des études récentes ont décrit des méthodes pour réduire cette exposition [7][8][9][10][11][12][13][14] tels l'utilisation de divers systèmes et supports d'imagerie (tomodensitométrie peropératoire (CT) combinée à la navigation) [15][16][17]. Ces systèmes sont coûteux et ne sont disponibles que dans une minorité de centres, laissant la majorité utiliser un ou deux C-arm conventionnels.…”