Intraoperative Imaging System Research Articles

Fluorescent imaging probes for in vivo ovarian cancer targeted detection and surgery.

Ovarian cancer is the most lethal gynecological cancer, with a survival rate of approximately 40% at five years from the diagno. The first-line treatment consists of cytoreductive surgery combined with chemotherapy (platinum- and taxane-based drugs). To date, the main prognostic factor is related to the complete surgical resection of tumor lesions, including occult micrometastases. The presence of minimal residual diseases not detected by visual inspection and palpation during surgery significantly increases the risk of disease relapse. Intraoperative fluorescence imaging systems have the potential to improve surgical outcomes. Fluorescent tracers administered to the patient may support surgeons for better real-time visualization of tumor lesions during cytoreductive procedures. In the last decade, consistent with the discovery of an increasing number of ovarian cancer-specific targets, a wide range of fluorescent agents were identified to be employed for intraoperatively detecting ovarian cancer. Here, we present a collection of fluorescent probes designed and developed for fluorescence-guided ovarian cancer surgery. Original articles published between 2011 and November 2022 focusing on fluorescent probes, currently under preclinical and clinical investigation, were searched in PubMed. The keywords used were targeted detection, ovarian cancer, fluorescent probe, near-infrared fluorescence, fluorescence-guided surgery, and intraoperative imaging. All identified papers were English-language full-text papers, and probes were classified based on the location of the biological target: intracellular, membrane, and extracellular.

Craniovertebral Junction Surgical Approaches: State of Art.

Surgical approaches directed toward craniovertebral junction (CVJ) can be addressed to the ventral, dorsal, and lateral aspects through a variety of 360° surgical corridors Herein, we report features, advantages, and limits of the updated technical support in CVJ surgery in clinical setting and dissection laboratories enriched by our preliminary surgical results of the simultaneous application of O-arm intraoperative neuronavigation and imaging system along with the 3D-4K EX in TOA for the treatment of CVJ pathologies.In the past 4years, eight patients harboring CVJ compressive pathologies underwent one-step combined anterior neurosurgical decompression and posterior instrumentation and fusion technique with the aid of exoscope and O-arm. In our equipped Cranio-Vertebral Junction Laboratory, we use fresh cadavers (and injected "head and neck" specimens) whose policy, protocols, and logistics have already been elucidated in previous works. Five fresh-frozen adult specimens were dissected adopting an FLA. In these specimens, a TOA was also performed, as well as a neuronavigation-assisted comparison between transoral and transnasal explorable distances.A complete decompression along with stable instrumentation and fusion of the CVJ was accomplished in all the cases at the maximum follow-up (mean: 25.3months). In two cases, the O-arm navigation allowed the identification of residual compression that was not clearly visible using the microscope alone. In four cases, it was not possible to navigate C1 lateral masses and C2 isthmi due to the angled projection unfitting with the neuronavigation optical system, so misleading the surgeon and strongly suggesting changing surgical strategy intraoperatively. In another case (case 4), it was possible to navigate and perform both C1 lateral masses and C2 isthmi screwing, but the screw placement was suboptimal at the immediate postoperative radiological assessment. In this case, the hardware displacement occurred 2months later requiring reoperation.

Deep UV-excited fluorescence microscopy installed with CycleGAN-assisted image translation enhances precise detection of lymph node metastasis towards rapid intraoperative diagnosis

Rapid and precise intraoperative diagnosing systems are required for improving surgical outcomes and patient prognosis. Because of the poor quality and time-intensive process of the prevalent frozen section procedure, various intraoperative diagnostic imaging systems have been explored. Microscopy with ultraviolet surface excitation (MUSE) is an inexpensive, maintenance-free, and rapid imaging technique that yields images like thin-sectioned samples without sectioning. However, pathologists find it nearly impossible to assign diagnostic labels to MUSE images of unfixed specimens; thus, AI for intraoperative diagnosis cannot be trained in a supervised learning manner. In this study, we propose a deep-learning pipeline model for lymph node metastasis detection, in which CycleGAN translate MUSE images of unfixed lymph nodes to formalin-fixed paraffin-embedded (FFPE) sample, and diagnostic prediction is performed using deep convolutional neural network trained on FFPE sample images. Our pipeline yielded an average accuracy of 84.6% when using each of the three deep convolutional neural networks, which is a 18.3% increase over the classification-only model without CycleGAN. The modality translation to FFPE sample images using CycleGAN can be applied to various intraoperative diagnostic imaging systems and eliminate the difficulty for pathologists in labeling new modality images in clinical sites. We anticipate our pipeline to be a starting point for accurate rapid intraoperative diagnostic systems for new imaging modalities, leading to healthcare quality improvement.

Development and evaluation of an active motion compensation-based optical imaging system for living tissue

Imaging the surgical margin in vivo at microscopic level can help surgeons make a rapid pathological diagnosis intraoperatively. However, the motion of living tissue induced by respiration or heartbeat remains the critical challenge for the intraoperative microscopic imaging system. In this study, we propose an active motion compensation (AMC) based fluorescence microscopic system to reduce the effect of tissue movement, for which the emitted fluorescent signals are not only to construct the microscopic images, but also to measure the motion of living tissue. To validate the proposed method, an experimental prototype was developed. Then, using this prototype, a series of experiments in vitro and in vivo as well as simulation studies have been conducted for evaluation and validation purposes. In this paper, the proposed AMC-based microscopic imaging system might advance the intraoperative pathological diagnosis technologies.

P41. Evaluation and outcome comparison of biplanar projection radiographs to 3D intraoperative imaging systems

P41. Evaluation and outcome comparison of biplanar projection radiographs to 3D intraoperative imaging systems

Image quality and radiation dose in spinal surgery: a comparison of three imaging systems in phantom.

Using optimal settings for x-ray scans is crucial for obtaining three-dimensional images of high quality while keeping the patient dose low. Our work compares dose and image quality (IQ) of three intraoperative imaging systems [O-arm cone-beam computed tomography (CBCT), ClarifEye C-arm CBCT, and Airo computed tomography] used for spinal surgery. Patients of 70, 90, and 110kg were simulated with an anthropomorphic phantom by adding tissue-equivalent material. Titanium inserts were placed in the phantom spine for reproducing metal artifacts in the images. Organ dose was measured with thermo-luminescent dosimeters for effective dose () calculation. Subjective IQ was assessed by ranking the images acquired with the manufacturer-defined imaging protocols. Objective IQ was assessed with a customized Catphan phantom. The ClarifEye protocols resulted in the lowest ranging from 1.4 to 5.1mSv according to phantom size and protocol. The highest was measured for the high-definition protocol of O-arm ( 2.2 to 9mSv) providing the best subjective IQ for imaging of the spine without titanium inserts. For the images with metal, the best IQ was obtained with ClarifEye. Airo ( 5.5 to 8.4mSv) was ranked with the lowest IQ for images without metal while the rank improved for images with metal. Airo images had better uniformity, noise, and contrast sensitivity compared with CBCTs but worse high-contrast resolution. The values of these parameters were comparable between the CBCT systems. Both CBCT systems provided better IQ compared with Airo for navigation of lumbar spinal surgery for the original phantom. Metal artifacts particularly affect O-arm images decreasing the subjective IQ. The high spatial resolution of CBCT systems resulted in a relevant parameter for the visibility of anatomical features important for spine navigation. Low dose protocols were enough to obtain a clinically acceptable contrast-to-noise ratio in the bones.

Use of intraoperative 3D imaging in the maxillofacial operating room: A French national survey

PurposeTo gain a comprehensive understanding of the utilization of intraoperative 3D imaging among maxillofacial surgeons practicing in France through a web-based questionnaire. MethodsAn 18-point multiple-choice questionnaire was developed and distributed to participants. The questionnaire was divided into two sections, with the first section gathering general information about the respondents and the second section providing an overview of the utilization of 3D imaging techniques, such as cone-beam computed tomography (CBCT), computed tomography (CT) scan, and magnetic resonance imaging (MRI), including the conditions, frequencies, and indications for use, with a particular focus on the number of acquisitions per procedure and the other departments with whom the equipment is shared. ResultsA total of 75 participants completed the survey, with 30% of university hospital departments and 0% of private clinics currently utilizing intraoperative 3D imaging systems. The main indications for 50% of the users were for temporomandibular joint surgery and orbital fractures. ConclusionThe results of this survey indicate that the utilization of intraoperative 3D imaging in French maxillofacial surgery is limited to university centers, with poor utilization and a lack of standardization in indications for use.

Surgical navigation in maxillofacial surgery: A French national survey

Purposeto gain a national understanding of the utilization of surgical navigation among maxillofacial surgeons in France through a web-based questionnaire. MethodsA 14-point multiple-choice questionnaire was created and distributed to the participants, divided into two sections. The first section gathered general information about the respondents, and the second section provided an overview of the use of surgical navigation. ResultA total of 75 participants completed the survey. The results showed that a majority of university hospital departments (65%) utilize an intra-operative 3D imaging system, while very few private clinics and general hospitals use this technology. ConclusionThe survey suggests that surgical navigation is primarily used in university centers in French maxillofacial surgery, with limited utilization and non-standardized indications for use.

Learning Curve of Real-Time Imaging with C-Arm Based Tomography for Peripheral Lung Nodule Biopsy.

The number of procedures required to attain proficiency with new bronchoscopic biopsy technologies for peripheral pulmonary lesions (PPLs) is uncertain. A prospective, single-center study evaluated learning curves of two operators performing PPL biopsies using a novel, real-time, intraoperative tomographic imaging system in consecutive procedures in adults with CT-detected PPLs. Operators were considered "proficient" when they asked three or fewer questions of the manufacturer's clinical representative with no subsequent navigations in which they asked more than three questions. A total of 31 procedures were performed on 31 patients (Operator 1: 18, Operator 2: 13). Proficiency was achieved after an average of 10 procedures (Operator 1: 12, Operator 2: 8). From the learning curve to the post-learning curve period, the number of questions (median [IQR]: 23 [9.5-41.5] versus 0 [0-1], p < 0.001) and radiation dose (median [IQR]: 19.5 mGy/m2 [1.9-43.5] versus 1.5 mGy/m2 [0.7-3.3], p = 0.05) decreased significantly; procedure time decreased (median [IQR]: 12 min [7-20] versus 8 min [3-15], p = 0.29); and diagnostic yield increased significantly (13/20 cases [65%] to 11/11 cases [100%]), (p = 0.03). Based on this unique, clinically relevant method of assessing learning curve, proficiency with the Body Vision system was achieved at approximately the tenth procedure. These findings require validation in larger, diverse populations.

Abstract OT1-12-04: MRO PMS study - Intraoperative Specimen Magnetic Resonance Imaging System for Intraoperative Margin Assessment for Invasive Breast Cancer Using the ClearCoast™ System in Breast Conserving Surgery

Abstract Background Re-operation for involved margins in breast conserving surgery is associated with worse cosmetic outcome, increased medical costs, and patient anxiety. Therefore, obtaining negative margins during primary BCS is essential. In our prior non-interventional study, published in October 2021 (Thill M et al., J Surg Oncol 2021) the re-operation rate would have been reduced by 83% for invasive carcinoma, from 10% to 2%, and 50% for DCIS, from 30% to 15% re-operations, if results had not been blinded for the surgeon. The results suggested a potential reduction of the re-operation rate by up to 80% for patients undergoing BCS. Aim of the study Aim of our current study is to evaluate the interventional performance of the ClearCoast™ system (ClearCut Medical, Ltd.) in assessing surgical margins for IBC in breast conserving surgery (BCS) and reducing the re-excision rates. Material and Methods The ClearCoast™ system utilizes a diffusion-weighted-imaging (DWI) protocol to create 2D surface maps showing T2*, a MR parameter related to the tissue’s apparent diffusion coefficient (ADC), with a depth penetration of 1mm. ADC is a highly accurate differentiator for irregular versus normal tissue. From May 2021 till to date a prospective, non- blinded post marketing study (N=93), evaluating the performance of the ClearCoast™ system is currently ongoing in the Breast Centre at the AGAPLESION MARKUS KRANKENHAUS, Frankfurt, Germany. After standard evaluation with ultrasound and/or X-ray with or without wire or clip marking, the specimens are intraoperatively scanned with the ClearCoast™ system, and positive margins will lead to a direct re-resection by decision of the surgeon applying a simple T2* threshold to flag irregular tissue. The final histopathology results will be compared with the scan results on a margin per margin bases. In addition, the rates of recurrent surgery of the interventional group will be compared with those of a historical group on the bases of matched pairs. Primary endpoint of the study is the re-excision rates in both the interventional and the historical standard of care group. To date, 64 patients are enrolled in the trial, therefore, results of the trial may be presented at the SABCS 2022. Citation Format: Marc Thill, Katharina Kelling, Viviane van Haasteren, Tina Schnitzbauer, Petia Kiene, Anna Levin, Eyal Kolka, Zachi Peles, Sebastian Aulmann. MRO PMS study - Intraoperative Specimen Magnetic Resonance Imaging System for Intraoperative Margin Assessment for Invasive Breast Cancer Using the ClearCoast™ System in Breast Conserving Surgery [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT1-12-04.

Defining the relevance of surgical margins. Part two: Strategies to improve prediction of recurrence risk.

Due to the complex nature of tumour biology and the integration between host tissues and molecular processes of the tumour cells, a continued reliance on the status of the microscopic cellular margin should not remain our only determinant of the success of a curative-intent surgery for patients with cancer. Based on current evidence, relying on a purely cellular focus to provide a binary indication of treatment success canprovide an incomplete interpretation of potential outcome. A more holistic analysis of the cancer margin may be required. If we are to move ahead from our current situation - and allow treatment plans to be more intelligently tailored to meet the requirements of each individual tumour - we need to improve our utilisation of techniques that either improve recognition of residual tumour cells within the surgical field or enable a more comprehensive interrogation of tumour biology that identifies a risk of recurrence. In the second article in this series on defining the relevance of surgical margins, the authors discuss possible alternative strategies for margin assessment and evaluation in the canine and feline cancer patient. Thesestrategies includeconsidering adoption of the residual tumour classification scheme; intra-operative imaging systems including fluorescence-guided surgery, optical coherence tomography and Raman spectroscopy; molecular analysis and whole transcriptome analysis of tissues; and the development of a biologic index (nomogram). These techniques may allow evaluation of individual tumour biology and the status of the resection margin in ways that are different to our current techniques. Ultimately, these techniques seek to better define the risk of tumour recurrence following surgery and provide the surgeon and patient with more confidence in margin assessment.

First ground-based, high-field, cryogen-free, mobile intraoperative magnetic resonance imaging system

Background/ObjectiveAccurately targeting specific regions of interest in the brain is pivotal for the success of neurosurgical procedures. For example, the outcome of brain tumor resection is improved dramatically when surgeons are better able to define surgical borders. Intraoperative magnetic resonance imaging (iMRI) helps reduce the risk of damaging critical areas of the brain and makes it possible to confirm a successful resection or determine the need for further resection prior to closing a patient’s head and finalizing the surgery. Here we present a ground-based, iMRI system with a mobile 1-T cryogen-free imager. MethodsAn ex-vivo experimental test of the novel iMRI system is performed to demonstrate preoperative and intraoperative imaging. ResultsThe ground-based, mobile iMRI system presented here was successfully used to obtain intraoperative MR images without moving the imaging target or compromising conventional surgical techniques. ConclusionThe success of this experiment constitutes a major milestone towards the installation of a ground-based, high-field, mobile iMRI system in a hospital setting.

The Evolution of Minimally Invasive Spine Tumor Resection and Stabilization: From K-Wires to Navigated One-Step Screws.

Minimization of the surgical approaches to spinal extradural metastases resection and stabilization was advocated by the 2012 Oncological Guidelines for Spinal Metastases Management. Minimally invasive approaches to spine oncology surgery (MISS) are continually advancing. This paper will describe the evolution of minimally invasive surgical techniques for the resection of metastatic spinal lesions and stabilization in a single institute. A retrospective analysis of patients who underwent minimally invasive extradural spinal metastases resection during the years 2013-2019 by a single surgeon was performed. Medical records, imaging studies, operative reports, rates of screw misplacement, operative time and estimated blood loss were reviewed. Detailed description of the surgical technique is provided. Of 138 patients operated for extradural spinal tumors during the study years, 19 patients were treated in a minimally invasive approach and met the inclusion criteria for this study. The mortality rate was significantly improved over the years with accordance of improve selection criteria to better prognosis patients. The surgical technique has evolved over the study years from fluoroscopy to intraoperative 3D imaging and navigation guidance and from k-wire screw insertion technique to one-step screws. Minimally invasive spinal tumor surgery is an evolving technique. The adoption of assistive devices such as intraoperative 3D imaging and one-step screw insertion systems was safe and efficient. Oncologic patients may particularly benefit from the minimization of surgical decompression and fusion in light of the frailty of this population and the mitigated postoperative outcomes associated with MIS oncological procedures.

Next step trauma and orthopaedic surgery: integration of augmented reality for reduction and nail implantation of tibial fractures

IntroductionThere is a tremendous scope of hardware and software development going on in augmented reality (AR), also in trauma and orthopaedic surgery. However, there are only a few systems available for intra-operative 3D imaging and guidance, most of them rely on peri- and intra-operative X-ray imaging. Especially in complex situations such as pelvic surgery or multifragmentary multilevel fractures, intra-operative 3D imaging and implant tracking systems have proven to be of great advantage for the outcome of the surgery and can help reduce X-ray exposure, at least for the surgical team (Ochs et al. in Injury 41:1297 1305, 2010). Yet, the current systems do not provide the ability to have a dynamic live view from the perspective of the surgeon. Our study describes a prototype AR-based system for live tracking which does not rely on X-rays.Materials and methodsA protype live-view intra-operative guidance system using an AR head-mounted device (HMD) was developed and tested on the implantation of a medullary nail in a tibia fracture model. Software algorithms that allow live view and tracking of the implant, fracture fragments and soft tissue without the intra-operative use of X-rays were derived.ResultsThe implantation of a medullar tibia nail is possible while only relying on AR-guidance and live view without the intra-operative use of X-rays.ConclusionsThe current paper describes a feasibility study with a prototype of an intra-operative dynamic live tracking and imaging system that does not require intra-operative use of X-rays and dynamically adjust to the perspective of the surgeons due to an AR HMD. To our knowledge, the current literature does not describe any similar systems. This could be the next step in surgical imaging and education and a promising way to improve patient care.

Multispectral intraoperative imaging for the detection of the hemodynamic response to interictal epileptiform discharges.

Interictal epileptiform discharges (IEDs) are brief neuronal discharges occurring between seizures in patients with epilepsy. The characterization of the hemodynamic response function (HRF) specific to IEDs could increase the accuracy of other functional imaging techniques to localize epileptiform activity, including functional near-infrared spectroscopy and functional magnetic resonance imaging. This study evaluated the possibility of using an intraoperative multispectral imaging system combined with electrocorticography (ECoG) to measure the average HRF associated with IEDs in eight patients. Inter-patient variability of the HRF is illustrated in terms of oxygenated hemoglobin peak latency, oxygenated hemoglobin increase/decrease following IEDs, and signal-to-noise ratio. A sub-region was identified using an unsupervised clustering algorithm in three patients that corresponded to the most active area identified by ECoG.

Navigation accuracy and assessability of carbon fiber-reinforced PEEK instrumentation with multimodal intraoperative imaging in spinal oncology

Radiolucent carbon-fiber reinforced PEEK (CFRP) implants have helped improve oncological follow-up and radiation therapy. Here, we investigated the performance of 3D intraoperative imaging and navigation systems for instrumentation and precision assessment of CFRP pedicle screws across the thoraco-lumbar spine. Thirty-three patients with spinal tumors underwent navigated CFRP instrumentation with intraoperative CT (iCT), robotic cone-beam CT (rCBCT) or cone-beam CT (CBCT) imaging. Two different navigation systems were used for iCT-/rCBCT- and CBCT-based navigation. Demographic, clinical and outcome data was assessed. Four blinded observers rated image quality, assessability and accuracy of CFRP pedicle screws. Inter-observer reliability was determined with Fleiss` Kappa analysis. Between 2018 and 2021, 243 CFRP screws were implanted (iCT:93, rCBCT: 99, CBCT: 51), of which 13 were non-assessable (iCT: 1, rCBCT: 9, CBCT: 3; *p = 0.0475; iCT vs. rCBCT). Navigation accuracy was highest using iCT (74%), followed by rCBCT (69%) and CBCT (49%) (*p = 0.0064; iCT vs. CBCT and rCBCT vs. CBCT). All observers rated iCT image quality higher than rCBCT/CBCT image quality (*p < 0.01) but relevant pedicle breaches were reliably identified with substantial agreement between all observers regardless of the imaging modality. Navigation accuracy for CFRP pedicle screws was considerably lower than expected from reports on titanium implants and CT may be best for reliable assessment of CFRP materials.

The Dual-Targeted Peptide Conjugated Probe for Depicting Residual Nasopharyngeal Carcinoma and Guiding Surgery.

Detecting residual nasopharyngeal carcinoma (rNPC) can be difficult because of the coexistence of occult tumours and post-chemoradiation changes, which poses a challenge for both radiologists and surgeons using current imaging methods. Currently, molecular imaging that precisely targets and visualises particular biomarkers in tumours may exceed the specificity and sensitivity of traditional imaging techniques, providing the potential to distinguish tumours from non-neoplastic lesions. Here, we synthesised a HER2/SR-BI-targeted tracer to efficiently position NPC and guide surgery in living mice. This bispecific tracer contained the following two parts: IRDye 800 CW, as an imaging reagent for both optical and optoacoustic imaging, and a fusion peptide (FY-35), as the targeting reagent. Both in vitro and in vivo tests demonstrated that the tracer had higher accumulation and longer retention (up to 48 h) in tumours than a single-targeted probe, and realised sensitive detection of tumours with a minimum size of 3.9 mm. By visualising the vascular network via a customised handheld optoacoustic scan, our intraoperative fluorescence molecular imaging system provides accurate guidance for intraoperative tumour resection. Integrating the advantages of both optical and optoacoustic scanning in an intraoperative image-guided system, this method holds promise for depicting rNPC and guiding salvage surgery.

Application of the O-arm Intraoperative Imaging System to Assist Anterior Cervical Screw Fixation for Odontoid Fractures.

Odontoid fractures account for a large proportion of cervical spine fractures in the elderly, causing pain in the occiput and the back of the neck and restricting neck movement. Anterior cervical screw fixation is a common surgical procedure to treat odontoid fractures. Due to the special location and complex anatomy of the odontoid, surgeons need to perform intraoperative fluoroscopies repeatedly to ensure correct screw position and avoid damage to the peripheral nerves and vessels of the odontoid. The traditional anterior cervical screw fixation is usually conducted with the assistance of a C-arm. However, compared to the C-arm, an O-arm intraoperative imaging system can provide 3D images during surgery, which improves the accuracy of screw placement. This study retrospectively analyzed patients with anterior cervical odontoid fractures treated in our hospital. The application of the O-arm intraoperative imaging system for assisting screw placement in the treatment of odontoid fractures can reduce intraoperative blood loss, operation time, and trauma to the patients.

P119. Are biplanar projection radiographs sufficient to confirm intraoperative pedicle screw placement?

<h3>BACKGROUND CONTEXT</h3> Two-dimensional BPR (AP and lateral fluoroscopy or x-ray) has been the gold standard in spine fusion surgery for many years, however, 3D intraoperative imaging systems are now available. When utilizing BPR for pedicle screw confirmation, significant misplacement rates have been reported in the lumbar and thoracic spine. <h3>PURPOSE</h3> Biplanar projection radiographs (BPR) for confirmation of intraoperative pedicle screw placement are inferior to three-dimensional fluoroscopic (3D) imaging. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospectively collected data. <h3>PATIENT SAMPLE</h3> A total of 100 patients underwent degenerative spinal surgery by one spine surgeon. <h3>OUTCOME MEASURES</h3> Screw placement was compared between postoperative CT, intraoperative x-rays( BPR) and intraoperative 3D fluoroscopic imaging. <h3>METHODS</h3> One hundred patients underwent degenerative spinal surgery by one spine surgeon and screw placement was compared from preoperative CT images to intraoperative 3D fluoroscopy. The M-line and Gertzbein-Robbins system (GRS) was used to confirm false positives or negatives in BPR. M-line was defined as a line connecting the upper and lower spinous processes through the fixed vertebrae within BPR. GRS measures pedicle screw accuracy and categorizes positions into 4 groups based on a clinical positioning grading used in 3D imaging. <h3>RESULTS</h3> A total of 604 instrumented pedicles in 100 patients were planned robotically, 497 (82.2%) were placed robotically. Each patient received a postoperative CT, intraoperative X-rays (BPR), and intraoperative 3D fluoroscopic imaging. M-Lines were measured for each patient vias intraoperative X-ray postoperatively. Patient postoperative CTs were compared to intraoperative 3D fluoroscopy by the GRS method. Postoperative CTs were then compared to M-line findings in BPR, to confirm whether false positives or negatives were detected. Based on BPR imaging, 5 (5%) patients exhibited 5 (0.8%) screws which were all robotically placed screws crossing the M-line in BPR. However, when compared to their postoperative CT imaging, breach was not detected and was classified as fully within the pedicle (category A of GRS). A BPR in a separate patient (1%) did exhibit one screw (0.2%) with a false negative BPR compared to 3D imaging. This could be possibly due to anatomical rotation in BPR. <h3>CONCLUSIONS</h3> A clinically significant number of patients had false-negative and false-positive screw confirmation on BPR. In 5% of patients and 0.8% of screws, a false-negative breaching within robotically placed screws was seen. Furthermore, 1% of patients and 0.2% of screws showed a false negative of pedicle screw mal-positioning. BPR may yield a false sense of security for misplaced screws and conversely may raise concern over screws that are in a satisfactory position. These findings may make 3D imaging a more desirable post-instrumentation gold standard. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Bioimpedance Sensing Surgical Drill - In Vivo Porcine Model.

Surgical drilling to place dental implants in the mandible and maxilla is associated high risk of iatrogenic injuries to inferior alveolar nerve and maxillary sinus. Real-time tissue margin sensing at the drill-tip using electrical impedance spectroscopy (EIS) could reduce this risk by providing feedback to surgeons. Studies with saline analogues, ex-vivo tissues, in-situ tissues and computer models have been previously conducted to evaluate these impedance sensors. Understanding in-vivo electrical properties of tissues in the mandible and maxilla is critical to further develop the sensor and tissue margin sensing algorithms. In this paper, we propose an in-vivo animal model using pigs and discuss methods to test the sensor. Intra-operative imaging and optical tracking systems to assist in surgical navigation are described. The process of registering imaging and tracking information to localize impedance measurement sites within the anatomy are detailed. Results from one in-vivo case of drilling through the mandible are presented and discussed. Clinical Relevance- This model is crucial for characterizing in-vivo electrical properties of mandibular and maxillary tissues encountered during dental implant surgical drilling and for translating bioimpedance sensing drill technology to clinical space.