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Patients with an acute ischemic stroke (AIS) following cardiac catheterization (CC) generally do not receive intravenous thrombolysis [intravenous tissue plasminogen activator (IV-tPA)] as it is contraindicated due to the coagulopathy related to the heparin used during the procedure. We report a case of AIS successfully treated with IV thrombolysis following protamine reversal of heparin effect.An 87-year-old man with diabetes mellitus, hypertension, neurofibromatosis, and hyperlipidemia underwent elective transradial CC following an abnormal stress test. He had 2 drug-eluting stents for severe stenosis of mid-circumflex and right coronary arteries and received heparin 13,000 IU during procedure. He developed acute left hemiparesis with initial NIH stroke scale (NIHSS) of 4. Computed tomographic scan of the brain and computed tomographic angiogram of head and neck were unremarkable. Bedside activated clotting time was 181. Protamine 40 mg was administered and 30 minutes later, the activated clotting time level was normalized. IV-tPA was administered at 4 hours 25 minutes from his last known well. Within 15 minutes, his NIHSS was 0. Magnetic resonance imaging of brain showed no acute infarction 24 hours after stroke.There are limited reports of protamine reversal of heparin before IV-tPA administration. To our knowledge, there are only 6 AIS cases including ours. Three cases received 0.6 mg/kg of tPA dose. All have favorable outcomes and no intracranial hemorrhage was reported. Protamine reversal of heparin for AIS after CC seems to be safe. Further studies are needed to confirm the therapeutic safety and efficacy of this strategy.
To the Editor: We appreciate the analysis of and commentary1 on our recently published manuscript, "Microsurgical Anatomy of the Vertical Rami of the Superior Longitudinal Fasciculus: An Intraparietal Sulcus Dissection Study,"2 from Koutsarnakis et al.3 At the outset, we commend the authors on the rigor and detail of their recent work describing the complexity and vitality of the subcortical region underlying the superior parietal lobule and periatrial region. With respect to the comments by Koutsarnakis et al,3 their concerns fall into two general categories: The subcortical impact of the more posterior trajectory: May violate the inferior fronto-occipital fasciculus (IFOF) which may be more of an issue on the dominant hemisphere. A longer distance to the target The port corridor: The smaller and longer corridor may be restrictive for larger and more vascular lesions. COMMENT 1: POSTERIOR TRAJECTORY AND IMPACT ON THE SUBCORTICAL NETWORK (IFOF) The first issue raised by the authors is the selection of the posterior trajectory on the IFOF. In an effort to increase the safety of accessing subcortical parietal lobe lesions, as well as using this as a corridor en route to the ventricular trigone, we have chosen a more posterior trajectory at the intraparietal sulcus (IPS)-parietooccipital sulcus (POS) point ("Kassam-Monroy point"). The authors have commented that posteriorly tilting the trajectory may potentially damage the posterior portion of the IFOF which is a part of the ventral semantic pathway. They contend that this may increase language-related morbidity, especially in the dominant hemisphere. They specifically mentioned that in Figure 2C, which depicts anatomic dissections, the fibers of the IFOF have been resected along the posterior part of the IPS, en route to the ventricular trigone. Figure 2C, however, was not meant to be an exact representation of the surgical approach. Rather, the purpose of Figure 2C was to demonstrate a layer-by-layer dissection from the U-fibers to the callosal fibers and to illustrate the anatomic relationship between the IFOF, parieto-thalamic fibers, and the callosal fibers with the atrium. In the computer simulation, shown in the video included in the manuscript, we demonstrate the parafascicular layered dissection shown in the cadaveric dissection. Although the authors' observation is correct, the IFOF was intentionally resected in the cadaveric dissections to reveal the tapetum and the ventricular atrium posteriorly, it was done so for illustrative purposes, not to replicate the actual surgical approach. Figure 2C was constructed to demonstrate a sequential layer-by-layer panoramic and anatomic view of the parietal corridor, and guide the reader in understanding the relative position of the pertinent fibers as the surgeon travels from the surface en route to the atrium. The computer simulation allows for a "fly-by" view which is recreated in the cadaveric models via sequential fiber dissections, thus requiring the dissection of the IFOF. However, in clinical application, the surgical trajectory mimics the computer simulation, which is purposefully designed to parallel the fibers of the IFOF so as not to transect them. Figure 2C illustrates the "white-matter fiber" framework that sequentially surrounds the IPS-POS complex en route to the atrium, with the notion that pre-existing knowledge of the relative position of IFOF may be important when choosing the particular corridor, as it is in proximity to this trajectory and thus a key consideration in defining the parafascicular trajectory (see below). In addition, in the manuscript, we have described in detail the relative importance of the IFOF in the context of this subcortical framework and in relation to the IPS-POS complex: "This point we have termed the IPS-POS (Kassam-Monroy) Point and permits entry into a parafascicular zone leading to the atrium. This zone lies between SLF-II (laterally), and the projection fibers and SLF-I (medially), transecting the forceps major and extending superior and parallel to the oblique fibers of the MdLF-IPL and IFOF. Accessing the posterior third of the IPS in this fashion thus avoids the Vr." Explicitly, the port does not transect the IFOF but runs parallel to it, traversing fibers between IFOF and the Vr. While beyond the scope of this report, we have previously reported the concept of parafascicular surgery: specifically, the ability of the port to course at angles parallel to critical white matter tracts creating parafascicular corridor access to eloquent regions, including in the sensorimotor subcortical spaces.4,5 The authors also contend that the mid-entry point along the IPS is a safer option in avoiding damage to the IFOF. As previously mentioned, a more posterior trajectory does not increase the risk of damage of IFOF and Figure 2C was intended to provide a regional anatomic relationship of surrounding white matter fibers. In addition, moving the trajectory to the mid-entry point along the IPS may increase the risk of damage to the Vr that we describe here. The next subcortical issue raised by the authors was on the putative role of the Vr that we have proposed as an integrator of learning memory (motor, sensory, emotional, and visual). This is a valid point. We understand that, to date, there is no documented proof of the functional significance of the vertical rami fibers. We performed all of our cases under awake anesthesia with intraoperative neurocognitive and psychometric testing to somatotopically categorize changes based on real-time coordinates relative to these critical subcortical networks; it is based on this that we share our observations on the function of the Vr. Utilizing awake anesthesia, 3D tractography, and intraoperative neuronavigation and relating this fiber with nearby related fibers, and intraoperative neurocognitive testing are bringing us closer to establishing a definitive role of the Vr, which will require additional validation studies. COMMENT 2: RADIAL CORRIDOR The authors have commented that if the "access point along the sulcal length tilts more posteriorly towards the IPS-POS meeting point, the surgical corridor accomplished becomes deeper and steeper…Thus, by deepening the operative field, the working corridor becomes considerably narrower and bimanual surgical dexterity more demanding." The authors raise an important point that may be a critical determinant in corridor selection to access a lesion. In our clinical practice, we routinely preplan a trajectory and choose an appropriate trajectory, in consideration of neural, vascular, and osseous structures, with reproducibility. In our paradigm, the primary consideration is the subcortical tract anatomy and the concept of developing a parafascicular corridor, ie, a corridor that parallels the key fascicular anatomy of the region. Based on this, it is not necessarily desirable to choose the shortest trajectory to the target; rather, in our experience, the safest parafascicular trajectory may be longer than the traditional approach. In addition, we are able to simulate trajectories with the port; explicitly, the port system is available in different lengths (maximum length of 9 cm) and is able to reach a majority of deep-seated targets. In our experience, despite the longer length, the trajectory reported was feasible and ergonomic for the user facilitating standard microsurgical technique assuming that optical chain is designed to deliver light down this small corridor. Explicitly, in our experience, the use of the Robotically Operated Video Optical Telescopic microscope (ROVOT-m) facilitated bimanual dissection (see below). Therefore, to reiterate, the most important factor in determining the appropriate trajectory is the relative position of neural structures; in this case, the WMTs surrounding the IPS en route to the atrium of the ventricle. In addition, neuronavigation, used with the port, guides the cannulation in real-time, preventing deviation from the preplanned trajectory to avoid inadvertent injury to the fibers that are situated parallel to the sulcus. The next issue raised by the authors is the ability to work inside a 13.5-mm port effectively when resecting fibrous and vascular lesions, and the possible need to convert to an open corridor that would be facilitated by their 3-cm deep sulcal dissection. Again, while beyond the scope of this report, we have published over the past decade the ability to address large and complex lesions using this port system, including the ability to resect large deep-seated AVMs.6,7 We have found that the 13.5-mm diameter port allows for adequate ability to perform bimanual dissection and microsurgical technique; explicitly, traction-counter-traction, sharp and blunt capsular dissection and hemostasis with bipolar coagulation can be accomplished safely and effectively in an air medium, respecting the principles of microdissection technique. Currently, these tasks are greatly facilitated with the implementation of an integrated exoscopic robotically controlled visualization system, namely the ROVOT-m, which delivers parallel light and deep field of view with a high resolution through the 13.5-mm diameter cannula. Even though there may be a learning curve with the use of the ROVOT-m in conjunction with the port, and their corroborative technology, we believe that this has not been prohibitive in accomplishing safe and maximal resection even for fibrous and vascular lesions.6-8 In addition, all cases utilizing the IPS-POS corridor with this technology were performed using this trajectory and the ROVOT-m under awake conditions, without the need for conversion into a conventional approach. SUMMARY In our manuscript, we have proposed several important concepts in accessing the parietal subcortical region and the lateral ventricular atrium via the IPS-POS Point (Kassam-Monroy Point) creating a more posteriorly based trajectory: We have devised a more posteriorly based corridor along the IPS-POS point in order to avoid the vertical rami of the superior longitudinal fasciculus (SLF), which we believe may be of critical importance in preventing common parietal lobe dysfunctions, such as visuospatial agnosia, and constructional and visual apraxia.9,10 This corridor was founded on core anatomic principles and supported by collaborative technology, such as diffusion-tensor imaging (DTI). With this novel purpose-built corridor, we have been able to plan the surgical trajectory in all cases with the application of DTI, resulting in enhanced conspicuity of the critical white matter tracts along the corridor. We appreciate the authors' comments that the use of the BrainPath port system (Nico Corporation, Indianapolis, Indiana) is a useful and elegant technique in trans-sulcal entry. The port has the ability to be co-registered with magnetic resonance imaging/computed tomography/DTI, to allow for dynamic intraoperative neuronavigation at all times during surgery. Given the angle of incidence of the port to the U-fibers, the port does transect these fibers; however, the trajectory is created to optimize parallelity to the other key subcortical fibers. In this particular corridor, the parafascicular corridor is purposefully designed to create access with the 0.9-mm atraumatic tip of the port to optimize preservation of the SLF I and II, MdLF-IP, IFOF, corona radiata, and callosal fibers. The technique does not require dissecting down the 3 cm depth of the sulcus, as the authors suggest; rather, only 2 mm of dissection is needed along the depth to allow the port to cannulate the sulcus. We have personally performed over 500 such cannulations and have separately reported several serial series documenting the safety of this in multiple subgroups.6-8,11-15 This approach results in less damage to the white matter fibers, as compared to traditional methods, with the intent to displace rather than transect the fibers. This process is aided by the ability to utilize real-time intraoperative neuronavigation when passing the port through the sulcus. With respect to the IFOF in the dominant and nondominant hemisphere, we have analyzed a series of 10 cases performed by the senior author using this corridor and have not observed an alteration in language, independent of laterally (this series will be reported separately). Of note, with respect to the IFOF, given that all of our procedures are performed with the patient awake and with continuous detailed intraoperative neurocognitive and psychometric testing, we use real-time assays to identify semantic language deficits were they to occur. We thank the authors for their interest in our work, comments, and feedback, and commend them on their efforts in describing this surgically and anatomical complex area. Disclosures This research is supported by an award to the Aurora Research Institute by the Vince Lombardi Cancer Foundation. We would like to thank Nico Corporation, Carl Zeiss, Synaptive Medical, Stryker Medical, and Karl Storz for their donations that made our research possible in the Neuroanatomy Laboratory. Dr Kassam reports involvement in Synaptive Medical (consultant), KLS Martin (consultant), Medtronic (advisory board), and founder and CEO of Neeka Health, LLC. Mark Lindsey reports involvement in Neeka Health, LLC (consultant).
Objective The aim of this study is to determine feasibility of incorporating three-dimensional (3D) tractography into routine skull base surgery planning and analyze our early clinical experience in a subset of anterior cranial base meningiomas (ACM). Methods Ninety-nine skull base endonasal and transcranial procedures were planned in 94 patients and retrospectively reviewed with a further analysis of the ACM subset. Main Outcome Measures (1) Automated generation of 3D tractography; (2) co-registration 3D tractography with computed tomography (CT), CT angiography (CTA), and magnetic resonance imaging (MRI); and (3) demonstration of real-time manipulation of 3D tractography intraoperatively. ACM subset: (1) pre- and postoperative cranial nerve function, (2) qualitative assessment of white matter tract preservation, and (3) frontal lobe fluid-attenuated inversion recovery (FLAIR) signal abnormality. Results Automated 3D tractography, with MRI, CT, and CTA overlay, was produced in all cases and was available intraoperatively. ACM subset : 8 (44%) procedures were performed via a ventral endoscopic endonasal approach (EEA) corridor and 12 (56%) via a dorsal anteromedial (DAM) transcranial corridor. Four cases (olfactory groove meningiomas) were managed with a combined, staged approach using ventral EEA and dorsal transcranial corridors. Average tumor volume reduction was 90.3 ± 15.0. Average FLAIR signal change was -30.9% ± 58.6. 11/12 (92%) patients (DAM subgroup) demonstrated preservation of, or improvement in, inferior fronto-occipital fasciculus volume. Functional cranial nerve recovery was 89% (all cases). Conclusion It is feasible to incorporate 3D tractography into the skull base surgical armamentarium. The utility of this tool in improving outcomes will require further study.
Introduction: Access to the posterior fossa via the presigmoid or far lateral approaches often requires removal of segments of the occipital condyle (OC), resulting in a potential need for spinal fixation to prevent craniocervical instability and the need to locate the hypoglossal canal to prevent damage to the hypoglossal nerve. Organization of the relative relationships of osseous and neurovascular structures in this region may assist the surgeon in dictating the extent of resection of the OC.
Abstract BACKGROUND: Subcortical injury resulting from conventional surgical management of intracranial hemorrhage may counteract the potential benefits of hematoma evacuation. OBJECTIVE: To evaluate the safety and potential benefits of a novel, minimally invasive approach for clot evacuation in a multicenter study. METHODS: The integrated approach incorporates 5 competencies: (1) image interpretation and trajectory planning, (2) dynamic navigation, (3) atraumatic access system (BrainPath, NICO Corp, Indianapolis, Indiana), (4) extracorporeal optics, and (5) automated atraumatic resection. Twelve neurosurgeons from 11 centers were trained to use this approach through a continuing medical education–accredited course. Demographical, clinical, and radiological data of patients treated over 2 years were analyzed retrospectively. RESULTS: Thirty-nine consecutive patients were identified. The median Glasgow Coma Scale (GCS) score at presentation was 10 (range, 5-15). The thalamus/basal ganglion regions were involved in 46% of the cases. The median hematoma volume and depth were 36 mL (interquartile range [IQR], 27-65 mL) and 1.4 cm (IQR, 0.3-2.9 cm), respectively. The median time from ictus to surgery was 24.5 hours (IQR, 16-66 hours). The degree of hematoma evacuation was ≥90%, 75% to 89%, and 50% to 74% in 72%, 23%, and 5.0% of the patients, respectively. The median GCS score at discharge was 14 (range, 8-15). The improvement in GCS score was statistically significant ( P < .001). Modified Rankin Scale data were available for 35 patients. Fifty-two percent of those patients had a modified Rankin Scale score of ≤2. There were no mortalities. CONCLUSION: The approach was safely performed in all patients with a relatively high rate of clot evacuation and functional independence.
