3-dimensional Navigation System Research Articles

A novel endocardial activation–derived predictor for focal paraseptal atrial tachycardias: Evidence from a multicenter cohort study

BackgroundThe electrocardiogram-based algorithm for predicting paraseptal atrial tachycardia (PSAT) is limited by the significant overlaps in P-wave morphology originating from various paraseptal sites. ObjectivesThe goals of this study were to investigate the endocardial activation characteristics of PSAT and to seek an endocardial activation–derived predictor for the ablation site. MethodsForty-four patients [11 men (25%); mean age 62.6 ± 14.7 years] with PSAT ablation in 4 tertiary medical centers were assigned to 3 groups according to the ablation site: right atrial (RA) para-Hisian region (group 1, n = 10), noncoronary cusp (NCC) (group 2, n = 13), and left atrial (LA) paraseptal area (group 3, n = 21). Multiple-chamber activation mapping was performed guided by a 3-dimensional navigation system. The discrepancies in the earliest activation time between 2 of 3 chambers (ΔRA-LA, ΔRA-NCC, and ΔLA-NCC) were calculated in each group and used for pairwise comparisons. ResultsThere was a significant difference in ΔRA-LA, ΔRA-NCC, and ΔLA-NCC among the 3 groups. ΔRA-LA was the only parameter that could consistently predict the ablation site of PSAT with good accuracy (area under the curve 1.000, sensitivity 100% and specificity 100%, and cutoff value 7 ms for predicting right para-Hisian or NCC ablation; area under the curve 0.974, sensitivity 92.3% and specificity 95.2%, and cutoff value −4 ms for predicting NCC or left paraseptal ablation). Based on 2 cutoff values, a 2-step algorithm was developed to predict the ablation site of PSAT with a positive predictive value of 95.4% and a negative predictive value of 97.0%. ConclusionΔRA-LA is a useful endocardial activation–derived parameter for predicting the successful ablation site of PSAT.

Removal of Orbital Metallic Foreign Bodies With Image-Guided Surgical Navigation.

To describe the use of an image-guided 3-dimensional surgical navigation system for the removal of metallic foreign bodies from the human intraorbital region. Between January 2016 and June 2019, 30 patients with metallic foreign bodies in the orbital area underwent image-guided 3-dimensional surgical navigational removal at the authors' center, and their data were retrospectively analyzed. Patients' age, gender, complaints, cause of initial injury, location, interval between injury, and surgery were recorded. Preoperative CT scans of the orbits were obtained and used for preoperative planning. The 3-dimensional navigation system was used for intraoperative navigation. In all 30 patients, the foreign bodies were removed by minimally invasive access without any severe complications. The intraoperative average depth of foreign bodies was 19.98 ± 11.47 mm which was consistent with the depth measured in preoperative planning. The mean length, width, and height of foreign bodies determined in preoperative planning were confirmed by postoperative measurements. There was no significant difference between preoperative and postoperative mean logarithm of Mininal Angle Resolution (logMAR) best-corrected visual acuity. According to the postoperative CT scan, all 30 patients' metallic foreign bodies were successfully removed by surgeries using the surgical navigation system. Most patients who presented with diplopia, eye movement pain, and paresthesia were improved after surgery. This study demonstrated that computer-assisted image-guided 3-dimensional surgical navigation had the advantages of accurate real-time localization of foreign bodies, minimizing collateral damage, determining the appropriate surgical path, and increasing the successful rate of foreign body retrieval.

Total Navigation in Spine Surgery; A Concise Guide to Eliminate Fluoroscopy Using a Portable Intraoperative Computed Tomography 3-Dimensional Navigation System.

Portable intraoperative computed tomography (iCT) with integrated 3-dimensional navigation (NAV) offers new opportunities for more precise navigation in spinal surgery, eliminates radiation exposure for the surgical team, and accelerates surgical workflows. We present the concept of "total navigation" using iCT NAV in spinal surgery. Therefore, we propose a step-by-step guideline demonstrating how total navigation can eliminate fluoroscopy with time-efficient workflows integrating iCT NAV into daily practice. A prospective study was conducted on collected data from patients undergoing iCT NAV-guided spine surgery. Number of scans, radiation exposure, and workflow of iCT NAV (e.g., instrumentation, cage placement, localization) were documented. Finally, the accuracy of pedicle screws and time for instrumentation were determined. iCT NAV was successfully performed in 117 cases for various indications and in all regions of the spine. More than half (61%) of cases were performed in a minimally invasive manner. Navigation was used for skin incision, localization of index level, and verification of implant position. iCT NAV was used to evaluate neural decompression achieved in spinal fusion surgeries. Total navigation eliminates fluoroscopy in 75%, thus reducing staff radiation exposure entirely. The average times for iCT NAV setup and pedicle screw insertion were 12.1 and 3.1 minutes, respectively, achieving a pedicle screw accuracy of 99%. Total navigation makes spine surgery safer and more accurate, and it enhances efficient and reproducible workflows. Fluoroscopy and radiation exposure for the surgical staff can be eliminated in the majority of cases.

Occipital-C2 Transarticular Fixation for Occipitocervical Instability Associated With Occipitalization of the Atlas in Patients With Klippel-Feil Syndrome, Using Intraoperative 3-Dimensional Navigation System

Retrospective case series. The aim of this study was to describe the clinical outcomes of cervical reduction and occipital-C2 transarticular (OCTA) fixation with an assistance of intraoperative 3-dimensional navigation system (ITNS) during the treatment of reducible occipitocervical instability (OCI) in patients with Klippel-Feil syndrome (KFS) with occipitalization of the atlas and fusion of C2-C3. Patients with KFS have congenital fusions of at least 2 cervical segments and may gradually develop symptoms at the hypermobile articulations adjacent to the cervical synostosis. This is particularly common in patients with KFS with occipitalization of the atlas and C2-C3 fusion. These patients may be at risk for instability and neurological complications of the occipitocervical junction that require occipitocervical reconstruction and fusion. Numerous treatment techniques are available for this pathological condition. However, there has yet to be a study of reducible OCI, showing successful treatment with intraoperative reduction and posterior OCTA fixation using ITNS. From 2006 to 2011, 9 patients with KFS with reducible OCI attributed to occipitalization of the atlas and C2-C3 fusion were surgically treated. After a limited foramen magnum decompression, reduction of the OCI was conducted by intraoperative cervical traction and extension, followed by OCTA fixation using a direct posterior approach and with the assistance of ITNS. The follow-up period ranged from 6 to 60 months (mean, 31 mo). Good decompression and bone fusion were achieved in all the patients. The clinical symptoms had improved for all patients. There were no intraoperative or postoperative complications. In patients with KFS with occipitalization of the atlas and C2-C3 fusion, manual cervical traction in tandem with cervical extension, followed by posterior OCTA fixation and fusion provides a safe, effective treatment of OCI and ventral brainstem impingement. IFTN is a feasible tool for monitoring cervical reduction and OCTA screw insertion in patients with KFS with this pathological condition.

Development of Stereotactic Mass Spectrometry for Brain Tumor Surgery

Surgery remains the first and most important treatment modality for the majority of solid tumors. Across a range of brain tumor types and grades, postoperative residual tumor has a great impact on prognosis. The principal challenge and objective of neurosurgical intervention is therefore to maximize tumor resection while minimizing the potential for neurological deficit by preserving critical tissue. To introduce the integration of desorption electrospray ionization mass spectrometry into surgery for in vivo molecular tissue characterization and intraoperative definition of tumor boundaries without systemic injection of contrast agents. Using a frameless stereotactic sampling approach and by integrating a 3-dimensional navigation system with an ultrasonic surgical probe, we obtained image-registered surgical specimens. The samples were analyzed with ambient desorption/ionization mass spectrometry and validated against standard histopathology. This new approach will enable neurosurgeons to detect tumor infiltration of the normal brain intraoperatively with mass spectrometry and to obtain spatially resolved molecular tissue characterization without any exogenous agent and with high sensitivity and specificity. Proof of concept is presented in using mass spectrometry intraoperatively for real-time measurement of molecular structure and using that tissue characterization method to detect tumor boundaries. Multiple sampling sites within the tumor mass were defined for a patient with a recurrent left frontal oligodendroglioma, World Health Organization grade II with chromosome 1p/19q codeletion, and mass spectrometry data indicated a correlation between lipid constitution and tumor cell prevalence. The mass spectrometry measurements reflect a complex molecular structure and are integrated with frameless stereotaxy and imaging, providing 3-dimensional molecular imaging without systemic injection of any agents, which can be implemented for surgical margins delineation of any organ and with a rapidity that allows real-time analysis.

F-18 Positron Emission Tomography and Computed Tomography Image-Fusion for Image-Guided Detection of Local Recurrence in Patients With Head and Neck Cancer Using a 3-Dimensional Navigation System: A Preliminary Report

[18F]-2-fluorodeoxyglucose positron emission tomography (F-18 FDG-PET) has played an important role recently in the staging process for squamous cell carcinoma of the head and neck (SCCHN).1 Various studies show a high sensitivity and specificity in detection of nodal metastases with this imaging modality.2-5 Moreover, FDG-PET also has played a significant role in differentiating residual/recurrent disease from treatment-induced normal tissue changes.6 Some authors show a sensitivity and specificity up to 100%, in contrast to the 75% sensitivity and 80% specificity of computed tomography (CT)/magnetic resonance imaging (MRI).