Description and comparison of workflow and performance of intraoperative CT, cone-beam CT and robotic cone-beam CT in the context of spinal navigation

Einleitung Die rasche Weiterentwicklung und der zunehmende Einsatz von Systemen zur navigierten Implantation von Pedikelschrauben im Bereich der gesamten Wirbelsäule hat in den letzten Jahrzehnten zur Einführung des intraoperativen CTs (iCT), Cone Beam CTs (CBCT) und robotischen Cone Beam CTs (rCBCT) geführt. Diese Bildgebungsmodalitäten erstellen hochauflösende 3D-Datensätze des Operationsgebietes und liefern hiermit die Grundlage für die spinale Navigation. Die Vorteile dieser Technologie liegen in einer höheren Präzision bezüglich der Pedikelschraubenimplantation, der Möglichkeit der intraoperativen Lagekontrolle und Revision, sowie einer reduzierten Strahlenexposition für Mitarbeiter im OP. Diese Studie untersucht die Anwendung von iCT, CBCT und rCBCT im Rahmen der spinalen Navigation hinsichtlich Präzision, Workflow und Handling innerhalb eines standardisierten Umfeldes. Methodik Der Untersuchungszeitraum dieser Studie betrug 24 Monate ab Einführung der jeweiligen Untersuchungsmodalität. Von 2014 bis 2018 wurden insgesamt 503 Patienten mittels navigierter Pedikelschraubenimplantation unter Anwendung von iCT, CBCT oder rCBCT in der Neurochirurgischen Klinik der Charité – Universitätsmedizin Berlin behandelt. Im obengenannten Zeitraum wurden insgesamt 2673 Schrauben implantiert. Die Patientenpopulation wurde anhand von klinischen und demographischen Daten charakterisiert. Durch Auswertung der intraoperativen Bilddaten wurde die Präzision der implantierten Schrauben erhoben und anschließend statistisch ausgewertet. Workflow, Setup und Handling wurden im selben Arbeitsumfeld beobachtet und verglichen. Ergebnisse Die Präzision der Schraubenlage lag bei allen drei Modalitäten bei über 92% und eine sichere Schraubenimplantation und -beurteilung war mit allen drei Untersuchungsmethoden möglich. Das intraoperative CT zeigte bei langstreckigen Instrumentierungen Vorteile im Arbeitsablauf und im thorakalen Bereich Vorteile hinsichtlich der Präzision und Bildqualität. Das CBCT sowie das rCBCT bieten zusätzlich die Möglichkeit der 2D-Fluoroskopie und die Durchführung der CBCT und rCBCT 3D Bildgebung erfordert kein radiologisches Personal, sondern ist von einem Chirurgen mit entsprechender Strahlenschutzqualifikation (Fachkunde) durchführbar. Diskussion Erstmals wurden drei, der am meisten verwendeten intraoperativen Bildgebungsmodalitäten zur spinalen Navigation, in einem standardisierten Umfeld untersucht. Alle drei ermöglichten eine sichere und präzise Schraubenimplantation sowie eine intraoperative Schraubenevaluation und -revision. Auch bei der perkutanen Pedikelschraubenimplantation konnte eine verlässliche Präzision erzielt werden. Letztendlich sind es infrastrukturelle, organisatorische, personelle und finanzielle Aspekte, die zur Entscheidung für die eine oder andere Modalität führen. Die intraoperative Bildgebung in Kombination mit der spinalen Navigation bildet die Grundlage zur Implementierung von zukünftigen Technologien im Bereich der Wirbelsäulenchirurgie.Introduction The constant development and increasing use of systems for the navigated implantation of pedicle screws across the entire spine over the past decades has led to the introduction of intraoperative imaging solutions such as intraoperative CT (iCT), cone-beam CT (CBCT) and robotic cone-beam CT (rCBCT). These imaging modalities create high resolution 3D data sets of the surgical site and therefore build the foundation for spinal navigation. The advantages of this technology are higher precision in regard to pedicle screw implantation, the possibility of direct intraoperative screw assessment and revision, as well as reduced radiation exposure for the surgical team. This study investigated accuracy, workflow and handling of iCT, CBCT and rCBCT during spinal navigation in the same standardized environment. Methods The investigation period of this study included the first 24 months starting with the introduction of each imaging modality. Between 2014 and 2018, 503 patients underwent navigated implantation of pedicle screws using iCT, CBCT or rCBCT at the Department of Neurosurgery at the Charité University Medicine Berlin. A total number of 2673 pedicle screws were implanted. The patient population was characterized based on clinical and demographic data. Accuracy of implanted screws was evaluated according to intraoperative imaging data and statistically analyzed. Workflow, setup and handling were observed and evaluated within the same working environment. Results Pedicle screw accuracy was around 92% or higher for all three modalities. Safe pedicle screw implantation and evaluation was feasible with all three imaging methods. Intraoperative CT showed workflow advantages in cases requiring a larger scan area, next to precision and image quality advantages in the thoracic region. On the other hand, CBCT and rCBCT offered the possibility of 2D fluoroscopy and the execution of a 3D scan using CBCT and rCBCT did not require radiological assistance, but was instead independently possible by a surgeon with appropriate radiation protection qualification. Discussion For the first time three of the most commonly used intraoperative imaging modalities for spinal navigation have been investigated in a standardized environment. All three modalities allowed safe and precise implantation of pedicle screws as well as intraoperative evaluation and revision. Also, a high precision was achieved during percutaneous pedicle screw implantation. In the end, infrastructural, organizational and financial aspects seem to guide the decision for one or the other technology. Intraoperative imaging in combination with spinal navigation represents the foundation for the implementation of future technologies in the field of spine surgery

Lipocalin-2 as an Infection-Related Biomarker to Predict Clinical Outcome in Ischemic Stroke

Objectives From previous data in animal models of cerebral ischemia, lipocalin-2 (LCN2), a protein related to neutrophil function and cellular iron homeostasis, is supposed to have a value as a biomarker in ischemic stroke patients. Therefore, we examined LCN2 expression in the ischemic brain in an animal model and measured plasma levels of LCN2 in ischemic stroke patients. Methods In the mouse model of transient middle cerebral artery occlusion (tMCAO), LCN2 expression in the brain was analyzed by immunohistochemistry and correlated to cellular nonheme iron deposition up to 42 days after tMCAO. In human stroke patients, plasma levels of LCN2 were determined one week after ischemic stroke. In addition to established predictive parameters such as age, National Institutes of Health Stroke Scale and thrombolytic therapy, LCN2 was included into linear logistic regression modeling to predict clinical outcome at 90 days after stroke. Results Immunohistochemistry revealed expression of LCN2 in the mouse brain already at one day following tMCAO, and the amount of LCN2 subsequently increased with a maximum at 2 weeks after tMCAO. Accumulation of cellular nonheme iron was detectable one week post tMCAO and continued to increase. In ischemic stroke patients, higher plasma levels of LCN2 were associated with a worse clinical outcome at 90 days and with the occurrence of post-stroke infections. Conclusions LCN2 is expressed in the ischemic brain after temporary experimental ischemia and paralleled by the accumulation of cellular nonheme iron. Plasma levels of LCN2 measured in patients one week after ischemic stroke contribute to the prediction of clinical outcome at 90 days and reflect the systemic response to post-stroke infections

Intraoperative CT and cone-beam CT imaging for minimally invasive evacuation of spontaneous intracerebral hemorrhage

Background: Minimally invasive surgery (MIS) for evacuation of spontaneous intracerebral hemorrhage (ICH) has shown promise but there remains a need for intraoperative performance assessment considering the wide range of evacuation effectiveness. In this feasibility study, we analyzed the benefit of intraoperative 3-dimensional imaging during navigated endoscopy-assisted ICH evacuation by mechanical clot fragmentation and aspiration. Methods: 18 patients with superficial or deep supratentorial ICH underwent MIS for clot evacuation followed by intraoperative computerized tomography (iCT) or cone-beam CT (CBCT) imaging. Eligibility for MIS required (a) availability of intraoperative iCT or CBCT, (b) spontaneous lobar or deep ICH without vascular pathology, (c) a stable ICH volume (20–90 ml), (d) a reduced level of consciousness (GCS 5–14), and (e) a premorbid mRS ≤ 1. Demographic, clinical, and radiographic patient data were analyzed by two independent observers. Results: Nine female and 9 male patients with a median age of 76 years (42–85) presented with an ICH score of 3 (1–4), GCS of 10 (5–14) and ICH volume of 54 ± 26 ml. Clot fragmentation and aspiration was feasible in all cases and intraoperative imaging determined an overall evacuation rate of 80 ± 19% (residual hematoma volume: 13 ± 17 ml; p < 0.0001 vs. Pre-OP). Based on the intraoperative imaging results, 1/3rd of all patients underwent an immediate re-aspiration attempt. No patient experienced hemorrhagic complications or required conversion to open craniotomy. However, routine postoperative CT imaging revealed early hematoma re-expansion with an adjusted evacuation rate of 59 ± 30% (residual hematoma volume: 26 ± 37 ml; p < 0.001 vs. Pre-OP). Conclusions: Routine utilization of iCT or CBCT imaging in MIS for ICH permits direct surgical performance assessment and the chance for immediate re-aspiration, which may optimize targeting of an ideal residual hematoma volume and reduce secondary revision rates

Plasma levels of lipocalin-2 in patients obtained at a median of 7 (range 5–9) days after ischemic stroke onset.

<p>First, patients were dichotomized into favourable (mRS 0–2) and unfavourable (mRS 3–6) outcomes assessed 90 days after stroke. Second, patients were dichotomized if they had developed post-stroke infections or not. Plots display the median, interquartile range (box), 10^th and 90^th percentiles (whiskers); *p<0.05; **p<0.01. Abbreviation: mRS = modified Rankin Scale</p

Immunohistochemistry in the mouse brain after temporal middle cerebral artery occlusion (tMCAO).

<p>In adjacent serial sections at day 14 following tMCAO, cellular nonheme iron staining (<b>a</b>) co-localizes with macrophage/microglia (<b>b</b>) but not with glial fibrillary acidic protein (GFAP) immunoreactivity (<b>c</b>).</p

Predictive models for clinical outcome 90 days after ischemic stroke.

<p>Predictive models for clinical outcome 90 days after ischemic stroke.</p

Demographic data and clinical characteristics of patients.

<p>Demographic data and clinical characteristics of patients.</p