Electromagnetic Guidance Research Articles

Nasoenteral feeding tube placement by nurses using an electromagnetic guidance system (with )

The early institution of feeding in patients who need postpyloric feeding tubes is often hampered by a limited availability of endoscopists experienced in safe tube positioning. To test the feasibility of having nurses place postpyloric feeding tubes by using a universal path finding system device. Prospective study. Academic hospital. The success rate and learning curve of a senior nurse placing postpyloric feeding tubes in 50 patients was studied, followed by a study in 160 patients on the success rates and learning curves of 4 inexperienced nurses instructed by the senior nurse. Finally, the success rate of postpyloric feeding tube placement by the senior nurse in 50 critically ill patients was investigated. Postpyloric feeding tube positioning by nurses using an electromagnetic universal path-finding system device enabling them to follow the path of the tip of the feeding tube on a monitor screen. Success was defined by postpyloric positioning of the feeding tube. The ultimate aim was to reach at least the duodenojejunal flexure. In the first part, the senior nurse was successful in 72% of cases. There was a clear learning curve. In the second part, the 4 newly instructed nurses had a success rate of 89.4% without an evident learning curve. In the third part, successful feeding tube positioning was achieved in 78% of critically ill patients. Of the 217 successfully positioned tubes, 74% reached at least the duodenojejunal flexure. In half of the unsuccessful cases, an explanation for the failure was found at endoscopy. No complications were seen. The generalization to less-specialized hospitals should be investigated. Postpyloric positioning of feeding tubes by nurses at the bedside without endoscopy is feasible and safe. Nurses may take over some of the tasks of doctors in a time of high endoscopic needs.

Application of electromagnetic technology to neuronavigation: a revolution in image-guided neurosurgery

The authors investigated the practicality of electromagnetic neuronavigation in routine clinical use, and determined the applications for which it is at the advantage compared with other systems. A magnetic field is generated encompassing the surgical volume. Devices containing miniaturized coils can be located within the field. The authors report on their experience in 150 cases performed with this technology. Electromagnetic neuronavigation was performed in 44 endoscopies, 42 ventriculoperitoneal shunt insertions for slit ventricles, 21 routine shunt insertions, 6 complex shunt insertions, 14 external ventricular drain placements for traumatic brain injury, 5 awake craniotomies, 5 Ommaya reservoir placements, and for 13 other indications. Satisfactory positioning of ventricular catheters was achieved in all cases. No particular changes to the operating theater set-up were required, and no significant interference from ferromagnetic instruments was experienced. Neurophysiological monitoring was not affected, nor did it affect electromagnetic guidance. Neuronavigation enables safe, accurate surgery, and may ultimately reduce complications and improve outcome. Electromagnetic technology allows frameless, pinless, image-guided surgery, and can be used in all procedures for which neuronavigation is appropriate. This technology was found to be particularly advantageous compared with other technologies in cases in which freedom of head movement was helpful. Electromagnetic neuronavigation was therefore well suited to CSF diversion procedures, awake craniotomies, and cases in which rigid head fixation was undesirable, such as in neonates. This technology extends the application of neuronavigation to routine shunt placement and ventricular catheter placement in patients with traumatic brain injury.

Electromagnetic navigation guided bronchoscopy.

This review describes the technique and applications of an emerging bronchoscopic approach utilizing three-dimensional reconstructions of chest computed tomography scans to facilitate electromagnetic guidance to peripheral lung nodules. This approach, electromagnetic navigation bronchoscopy, is useful for biopsy, placement of fiducial markers, or dye marking of overlying pleura prior to thoracoscopic wedge resection. This technique offers some potential advantages over other forms of biopsy. The design, application, relative advantages and pitfalls of this system are the subject of this review.

Electromagnetic navigation in lung cancer: research update

Unfortunately, flexible bronchoscopy, the least invasive bronchoscopic procedure, is of limited value for obtaining tissue from lesions in the peripheral segments of the lung. Biopsy success is further compromised if the lesion is less than 3 cm in diameter. The main limitation of flexible bronchoscopy is the difficulty in reaching peripheral lesions with the accessory tools. In this paper, we will discuss a new bronchoscopic advance in the diagnosis and treatment of lung cancer. Once extended beyond the tip of the bronchoscope, these tools are difficult to guide to the desired location. Localizing the lesion under fluoroscopy is difficult, and alternative diagnostic guidance methods, such as computer tomography-guided bronchoscopy and endobronchial ultrasound, are more demanding. Therefore, new methods for navigation and localization are needed. One of these new technologies is electromagnetic navigation bronchoscopy. The aim of this special report is to provide an analysis of the published literature. A literature search was constructed and performed on PubMed to identify the literature from 2000 to 2008. The search words were ‘electromagnetic navigation’, ‘coin lesion’, ‘solitary pulmonary nodule’ and ‘lung cancer’. We review a number of recent studies that utilize electromagnetic navigation and guidance, and analyze their performance characteristics for clinical applications of the technology. Electromagnetic navigation is likely to play an increasing and integral role in the diagnosis and staging of lung cancer in the near future. Electromagnetic registration may impact both the staging and diagnosis of peripheral lesions.

TH-C-303A-01: Initial Clinical Experience with Electromagnetic Localization and Tracking for External Beam Partial Breast Irradiation

Purpose: The Calypso® 4D Localization System™ (Calypso Medical) uses non‐ionizing ACelectromagnetic radiation to localize and track small wireless devices (called Beacon® transponders) implanted in or near a patient's tumor. We report on the first clinical experience with the use of the system for localizing and tracking the lumpectomy cavity during external‐beam accelerated partial breast irradiation (EB APBI). Method and Materials: The study included patients treated receiving EB APBI on an IRB approved protocol. Thirteen patients were implanted with both gold markers (GM) and beacon® transponders and two patients were implanted with beacon® tranponders alone. For patients in whom MRI follow‐up was anticipated, two removable interstitial breast catheters were inserted and afterloaded with gold markers and transponders. The catheters were removed post radiation therapy. Initial alignment was performed using lasers. For patients with gold markers, orthogonal images were used to obtain the necessary shift. The shift values were compared to the shift predicted under electromagnetic guidance. During treatment, Calypso was used to track the target motion. Results: Fifteen patients have been studied, and 93 treatment fractions were analyzed. The catheters and transponders overall showed good stability with inter‐transponder distance changes of less than 2 mm. Calypso based setup can be performed in less than 2 minutes. An average residual setup error of 10.29 mm was determined using gold markers. For the 63 fractions analyzed, the difference between the residual setup error determined by the GM and the Calypso system on average was 1.5 mm. Tracking showed regular motion in the range of 2–3 mm with occasional deeper breaths exceeding 4–5 mm. Conclusion: Results show excellent agreement between gold markers and electromagnetic guidance in EB APBI with electromagnetic guidance providing a more rapid setup and real time tracking during delivery. Research sponsored by Calypso Medical.

Feasibility and Safety of the Placement of Nasoduodenal Feeding Tubes By Nurses with the Assistance of An Electromagnetic Guidance System (Cortrak™)

Feasibility and Safety of the Placement of Nasoduodenal Feeding Tubes By Nurses with the Assistance of An Electromagnetic Guidance System (Cortrak™)

Placement of postpyloric tubes using electromagnetic guidance*

Placement of postpyloric tubes using electromagnetic guidance*

Successful placement of postpyloric enteral tubes using electromagnetic guidance in critically ill children*

Initiation of postpyloric feeding is often delayed by difficulties in placement of enteral tubes. We evaluated the effectiveness of bedside postpyloric enteral tube (PET) placement using an electromagnetic (EM)-guided device. We hypothesized that: 1) EM-guided placement of PETs would be successful more often than standard blind placement with a shorter total time to successful placement and 2) the EM-guided technique would have similar overall costs to the standard technique. Prospective cohort trial with serial control groups in a pediatric intensive care unit at a tertiary care children's hospital. We collected data on a cohort of consecutive pediatric intensive care unit patients who underwent PET placement by standard blind technique followed by a cohort who underwent EM-guided placement. The primary outcome measure was successful placement determined by abdominal radiography. One hundred seven patients were evaluated in the trial: 57 in the standard group and 50 in the EM-guided group. Demographic data, percent intubated, and admission diagnosis were similar in both groups. Forty-one of 50 patients (82%) in the EM-guided group had successful placement compared with 22 of 57 in the standard group (38%) (p < 0.0001). The average time to successful placement was 1.7 vs. 21 hours in the EM-guided group and standard group, respectively (p < 0.0001). Children in the EM-guided group received fewer radiographs (p = 0.007) and were given more prokinetic drugs (p = 0.045). There were no episodes of pneumothorax in either group. After controlling for prokinetic drug use, EM-guided placement was more likely to result in successful placement than the standard blind technique (odds ratio 6.4, 95% confidence interval 2.5-16.3). An annual placement rate of 250 PETs by EM guidance, based on our institution's current utilization rates, is associated with a cost savings of $55.46 per PET placed. EM guidance is an efficient and cost-effective method of bedside PET placement.

Clinical use of Electromagnetic Guidance for Lung and Spine Radiation Therapy

Clinical use of Electromagnetic Guidance for Lung and Spine Radiation Therapy

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

Background This cadaveric study compared efficacy and safety of an electromagnetic (EM) guidance system versus conventional fluoroscopy for percutaneous pedicle screw fixation. As percutaneous pedicle screw fixation becomes increasingly common in spinal surgery, intraoperative imaging systems that maximize efficiency while minimizing radiation exposure and inaccurate trajectories will be progressively more important. Published studies have validated the safety of percutaneous screw fixation using conventional fluoroscopic guidance and frameless optical stereotaxy, though EM guidance systems have not been evaluated for percutaneous placement in the lumbosacral spine. The aim of the study was to evaluate the clinical applicability of an EM system for minimally invasive spine fusion in the lumbosacral spine. Methods Five human cadaveric specimens underwent bilateral lumbosacral percutaneous screw fixation from L1 to S1 using conventional anteroposterior (AP) and lateral fluoroscopic techniques on one side and 2-dimesional (2D) EM guidance on each matching side. Intraoperative efficiency was evaluated, and pedicle, vertebral, and critical breach rates were assessed on postoperative computed tomography (CT). Results Overall mean fluoroscopy time per screw was 58.9 ± 44.7 seconds for conventional fluoroscopy 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 fluoroscopy and 42.8%, 10.7%, and 14.1% for electromagnetic guidance (difference not statistically significant [ns]). In comparing critical breaches in the lumbar spine (L1-L5), there was a significant difference between 2-D EM guidance (0) and CF guidance (6) ( P = .02). Conclusions Two-dimensional EM navigation provides a modality for lumbosacral percutaneous pedicle screw fixation that is more efficient and safer than conventional fluoroscopy. This data provides a foundation for further clinical trials of this technology. Level of Evidence Level 5 – Bench Research

Electromagnetic Navigational Bronchoscopy: A Surgeon’s Perspective

Diagnostic yield of flexible bronchoscopy is often limited by the size and location of the lesion of interest. Novel technologies have evolved that can improve the accuracy and expand the applicability of flexible bronchoscopy in rendering a tissue diagnosis for pulmonary nodules. One recent technical advance uses electromagnetic guidance to improve the ability of the bronchoscopist to navigate within the lung parenchyma as well as to localize and biopsy mediastinal pathology. We have gained a preliminary experience with navigational bronchoscopy using electromagnetic guidance to successfully biopsy peripheral lung lesions, place fiducial catheters to aid stereotactic radiotherapy, and to biopsy mediastinal lymph nodes in the staging of lung cancer. Not only will navigational bronchoscopy lead to improvements in the diagnostic yield of standard flexible bronchoscopy, but we envision potential therapeutic modalities that can be used this system.

Electromagnetic navigation in minimally invasive spine surgery: results of a cadaveric study to evaluate percutaneous pedicle screw insertion.

BackgroundThis cadaveric study compared efficacy and safety of an electromagnetic (EM) guidance system versus conventional fluoroscopy for percutaneous pedicle screw fixation. As percutaneous pedicle screw fixation becomes increasingly common in spinal surgery, intraoperative imaging systems that maximize efficiency while minimizing radiation exposure and inaccurate trajectories will be progressively more important. Published studies have validated the safety of percutaneous screw fixation using conventional fluoroscopic guidance and frameless optical stereotaxy, though EM guidance systems have not been evaluated for percutaneous placement in the lumbosacral spine. The 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 fixation from L1 to S1 using conventional anteroposterior (AP) and lateral fluoroscopic techniques on one side and 2-dimesional (2D) EM guidance on each matching side. Intraoperative efficiency was evaluated, and pedicle, vertebral, and critical breach rates were assessed on postoperative computed tomography (CT).ResultsOverall mean fluoroscopy time per screw was 58.9 ± 44.7 seconds for conventional fluoroscopy 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 fluoroscopy and 42.8%, 10.7%, and 14.1% for electromagnetic guidance (difference not statistically significant [ns]). In comparing critical breaches in the lumbar spine (L1-L5), there was a significant difference between 2-D EM guidance (0) and CF guidance (6) (P = .02).ConclusionsTwo-dimensional EM navigation provides a modality for lumbosacral percutaneous pedicle screw fixation that is more efficient and safer than conventional fluoroscopy. This data provides a foundation for further clinical trials of this technology.Level of EvidenceLevel 5 – Bench Research

Electromagnetic navigation improves minimally invasive robot-assisted lung brachytherapy

Objective: Recent advances in minimally invasive thoracic surgery have renewed an interest in the role of interstitial brachytherapy for lung cancer. Our previous work has demonstrated that a minimally invasive robot-assisted (MIRA) lung brachytherapy system produced results that were equal to or better than those obtained with standard video-assisted thoracic surgery (VATS) and comparable to results with open surgery. The purpose of this project was to evaluate the performance of an integrated system for MIRA lung brachytherapy that incorporated modified electromagnetic navigation and ultrasound image guidance with robotic assistance.Methods: The experimental test-bed consisted of a VATS box, ZEUS® and AESOP® surgical robotic arms, a seed injector, an ultrasound machine, video monitors, a computer, and an endoscope. Our previous custom-designed electromagnetic navigational software and the robotic controller were modified and incorporated into the MIRA III system to become the next-generation MIRA IV. Inactive brachytherapy seeds were injected as close as possible to a small metal ball target embedded in an opaque agar cube. The completion time, the number of attempts, and the accuracy of seed deployment were compared for manual placement, standard VATS, MIRA III, and the new MIRA IV system.Results: The MIRA IV system significantly reduced the median procedure time by 61% (104 s to 41 s), tissue trauma by 75% (4 attempts to 1 attempt), and mean seed placement error by 64% (2.5 mm to 0.9 mm) when compared to a standard VATS. MIRA IV also reduced the mean procedure time by 48% (85 s to 44 s) and the seed placement error by 68% (2.8 mm to 0.9 mm) compared to the MIRA III system.Conclusions: A modified integrated system for performing minimally invasive robot-assisted lung brachytherapy was developed that incorporated electromagnetic navigation and an improved robotic controller. The MIRA IV system performed significantly better than standard VATS and better than MIRA III.

Abstract 2672: Serial in vivo Non-invasive Imaging of Intramyocardially Injected Autologous Mesenchymal Stem Cells, Modified for Transgene Expression of Positron-Emission Tomography (PET) Reporter in Porcine Myocardial Infarction

Objective. The aim of our study was to elaborate an in vivo tracking method of the intramyocardially injected msenchymal stem cells (MSCs), modified for transgene expression of trifusion protein (lentiviral vector, expressing renilla luciferase /RL/, red fluoroscein protein /RFP/ and herpes simplex truncated thymidine kinase /tTK, positron emmission tomography PET-reporter gene/) using serial PET imaging in pig myocardial infarction (MI). Methods. Bone marrow (100 ml) was harvested from pigs immediately before induction of MI by percutaneous balloon occlusion of the LAD followed by reperfusion. The MSCs were selected and cultivated. The lentiviral vector LV-RL-RFP-tTK was inoculated into the MSCs under control of CMV promoter. The cells with the highest fluorescence intensity (after achieving appr. 50% transfection efficacy) were sorted, and tracked in vitro by PET using 9-(4-[18F]fluoro-3-hydroxymethylbutyl)-guanine (18FHBG). The transfected MSCs (at least 3 mio MSCs/ pigs) were then injected direct intramyocardially using NOGA electromagnetic guidance in pigs in 10 locations of the infarct border zone (min. 0.3 million cells/injection), followed by PET imaging 30 hours and 7 days later, after intravenous injection of 5 mCi 18FHBG. Results. The in vitro 18FHBG uptakes of the transgene modified MSCs by PET were 10 times larger than the control JY human B-lymphoblasts and T lymphocytes. The minimum number of the cells detectable with PET was 0.2 million. MRI of the pigs revealed a mean global EF of 47+/-3.5%. PET imaging displayed diffuse distribution of the injected MSCs with high activity of the PET tracer in the anterior wall and septum at 30h, and less tracer activity in the injections sites with diffuse distribution in the pericardium and pleura indicating the wandering of the living cells at 7 days. PET imaging did not show 18FHBG accumulation in the infarcted heart of the control animals. Myocardial histology with RL and RFP staining confirmed the distribution of the injected MSCs through an elongated track around the injected area, 9 days after delivery. Conclusion. In vivo tracking of gene-modified porcine MSCs by PET imaging is feasible and allows serial noninvasive imaging of homing and propagation of MSCs in pigs after MI.

E08-03: Innovative bronchoscopic diagnostic techniques: electromagnetic navigation

E08-03: Innovative bronchoscopic diagnostic techniques: electromagnetic navigation

(iv) Computer-assisted knee replacement techniques

<h2>Summary</h2> Implant alignment errors are associated with inferior results after total knee arthroplasty. Computer assistance supplements mechanical instrumentation by the addition of measurements which are used to locate landmarks, direct surgical tools and thereby better align prosthetic components. Modern navigation systems are based on infrared-light tracking or, more recently, on electromagnetic guidance. After initial scepticism a variety of systems have found acceptance and a remarkable number of clinical and laboratory studies have been published. There appears to be a consensus that computer assistance brings about a significant reduction in the number of outliers and improved varus/valgus, rotation and slope alignment of components. Most studies conclude with the prediction that individual and cumulative improvement in component alignment will ultimately lead to better long-term results. The controversies surrounding routine use of computer assistance in knee arthroplasy are discussed. Data analysis founded on navigated dynamic intra-operative investigation will possibly be the key to future implant design and alignment.

Robot‐assisted minimally invasive lung brachytherapy

This paper presents a novel alternative for the treatment of lung cancer. The method consists of accessing the lung through small incisions in a minimally invasive manner in order to insert radioactive seeds directly into the lung using a robotic surgical system. An experimental test-bed to evaluate the feasibility of this approach has been developed. It consists of two surgical robotic systems, a device specifically designed to robotically implant radioactive seeds, needle tracking software, ultrasound imaging, electromagnetic tracking, and a surgical box that mimics a patient's thorax. A detailed comparison has been performed between currently available access options and robot-assisted minimally invasive access. The results show insignificant differences in accuracy between the methods, with the exception of a significant improvement when electromagnetic (EM) guidance was added to the non-robotic techniques. The navigation system reduced the number of attempts for all seed delivery methods. Significant reductions in time were achieved in the minimally invasive procedures by the addition of EM guidance. The performance achieved when using robotic systems and image guidance for minimally-invasive brachytherapy is clinically comparable to that achieved in an open surgery procedure, while reducing the invasiveness of the procedure, improving ergonomic conditions for the clinician and reducing radiation exposure.

Electromagnetic Tracking–Guided Percutaneous Intrahepatic Portosystemic Shunt Creation in a Swine Model

Electromagnetic tracking potentially may be used to guide percutaneous needle-based interventional procedures. This brief report describes our initial experience with an electromagnetic guidance system featuring real-time tracking of respiratory-related target motion using an internal fiducial. An algorithm based on a "freehand" needle puncture technique was employed to puncture the right portal vein and a right hepatic vein for percutaneous intrahepatic portosystemic shunt in a swine model. Preoperative computed tomographic images registered with the electromagnetically tracked needle position were displayed for guidance. Successful puncture was confirmed angiographically. Simultaneous percutaneous transhepatic puncture of the targeted veins was accomplished on the initial attempt.

Navigational Bronchoscopy by Electromagnetic Guidance

Navigational Bronchoscopy by Electromagnetic Guidance

E8. Bronchoscopic biopsy of isolated, peripheral lung lesions underendobronchial ultrasound (EBUS) and electromagnetic guidance

E8. Bronchoscopic biopsy of isolated, peripheral lung lesions underendobronchial ultrasound (EBUS) and electromagnetic guidance