Examinando por Autor "Quiñones-Hinojosa, Alfredo"

Mostrando 1 - 3 de 3
  • Publicación
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    Aqueductal Cerebrospinal Fluid Stroke Volume Flow in a Rodent Model of Chronic Communicating Hydrocephalus: Establishing a Homogeneous Study Population for Cerebrospinal Fluid Dynamics Exploration
    (2019-08-05) Vivas-Buitrago, Tito; Lokossou, Armelle; Jusué-Torres, Ignacio; Pinilla-Monsalve, Gabriel; Blitz, Ari M.; Herzka, Daniel A.; Robison, Jamie; Xu, Jiadi; Guerrero-Cazares, Hugo; Mori, Susumu; Quiñones-Hinojosa, Alfredo; Baledént, Olivier; Rigamonti, Daniele; Neuro Ciencias
    Background Idiopathic normal pressure hydrocephalus (iNPH) is a cause of dementia that can be reversed when treated timely with cerebrospinal fluid (CSF) diversion. Understanding CSF dynamics throughout the development of hydrocephalus is crucial to identify prognostic markers to estimate benefit/risk to shunts. Objective To explore the cerebral aqueduct CSF flow dynamics with phase-contrast magnetic resonance imaging (MRI) in a novel rodent model of adult chronic communicating hydrocephalus. Methods Kaolin was injected into the subarachnoid space at the convexities in Sprague-Dawley adult rats. 11.7-T Bruker MRI was used to acquire T2-weighted images for anatomic identification and phase-contrast MRI at the cerebral aqueduct. Aqueductal stroke volume (ASV) results were compared with the ventricular volume (VV) at 15, 60, 90, and 120 days. Results Significant ventricular enlargement was found in kaolin-injected animals at all times (P < 0.001). ASV differed between cases and controls/shams at every time point (P = 0.004, 0.001, 0.001, and <0.001 at 15, 60, 90, and 120 days, respectively). After correlation between the ASV and the VV, there was a significant correlation at 15 (P = 0.015), 60 (P = 0.001), 90 (P < 0.001), and 120 days. Moreover, there was a significant positive correlation between the VV expansion and the aqueductal CSF stroke between 15 and 60 days. Conclusions An initial active phase of rapid ventricular enlargement shows a strong correlation between the expansion of the VV and the increment in the ASV during the first 60 days, followed by a second phase with less ventricular enlargement and heterogeneous behavior in the ASV. Further correlation with complementary data from intracranial pressure and histologic/microstructural brain parenchyma assessments are needed to better understand the ASV variations after 60 days.
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    Endoscope-assisted contralateral transmaxillary approach to the clivus and the hypoglossal canal: Technical case report
    (2019-05-05) Pamias-Portalatin, Eva; Mahato, Deependra; Rincon-Torroella, Jordina; Vivas-Buitrago, Tito; Quiñones-Hinojosa, Alfredo; Boahene, Kofi O.; Neuro Ciencias
    Clival lesions are still considered surgically complex due to their anatomical location. Critical structures, such as the internal carotid arteries (ICAs), cavernous sinuses, cranial nerves, and brainstem, may be encased within the lesion. Although advances in endoscopic endonasal approaches have provided new routes to these lesions, exposure and resection of clival tumors through the endonasal route remain a technical challenge. Here, the authors report a left-sided endoscopic transmaxillary approach to access the right aspect of the clivus and the hypoglossal canal.A 35-year-old woman presented with progressive right 6th cranial nerve palsy. MRI revealed a contrast-enhancing right petroclival chondrosarcoma that involved Meckel's cave and extended into the right hypoglossal canal. An endoscopic-contralateral-transmaxillary approach through a left sublabial incision was used to access the right petroclival region and right hypoglossal canal. A left maxillary osteoplastic flap was elevated to expose the left maxillary sinus. This was followed by a left medial maxillectomy, gaining access to the left posterior nasal cavity. The posterior third of the left inferior turbinate and nasal septum were removed to access the right side of the petroclival region. Near-total resection was achieved without any vascular or neurological complications. A thin shell of residual tumor was left behind due to involvement of vital structures, such as the ICA, and further treated with proton-beam radiotherapy.The endoscopic-contralateral-transmaxillary approach provides a direct surgical corridor and good lateral visualization of the skull base vasculature. This approach allows wide maneuverability around the ICA and hypoglossal canal, which, in this case, allowed maximal tumor resection with full preservation of neurological function.
  • Publicación
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    IDH–wild-type glioblastoma cell density and infiltration distribution influence on supramarginal resection and its impact on overall survival: a mathematical model
    (2021-10-29) Tripathi, Shashwat; Vivas-Buitrago, Tito; Domingo, Ricardo A.; De Biase, Gaetano; Brown, Desmond; Akinduro, Oluwaseun O.; Ramos-Fresnedo, Andres; Sherman, Wendy; Gupta, Vivek; Middlebrooks, Erik H.; Sabsevitz, David S.; Porter, Alyx B.; Uhm, Joon H.; Bendok, Bernard R.; Parney, Ian; Meyer, Fredric B.; Chaichana, Kaisorn L.; Swanson, Kristin R.; Quiñones-Hinojosa, Alfredo; Masira
    OBJECTIVE Recent studies have proposed resection of the T2 FLAIR hyperintensity beyond the T1 contrast enhancement (supramarginal resection [SMR]) for IDH–wild-type glioblastoma (GBM) to further improve patients’ overall survival (OS). GBMs have significant variability in tumor cell density, distribution, and infiltration. Advanced mathematical models based on patient-specific radiographic features have provided new insights into GBM growth kinetics on two important parameters of tumor aggressiveness: proliferation rate (ρ) and diffusion rate (D). The aim of this study was to investigate OS of patients with IDH–wild-type GBM who underwent SMR based on a mathematical model of cell distribution and infiltration profile (tumor invasiveness profile). METHODS Volumetric measurements were obtained from the selected regions of interest from pre- and postoperative MRI studies of included patients. The tumor invasiveness profile (proliferation/diffusion [ρ/D] ratio) was calculated using the following formula: ρ/D ratio = (4π/3)2/3 × (6.106/[VT21/1 − VT11/1])2, where VT2 and VT1 are the preoperative FLAIR and contrast-enhancing volumes, respectively. Patients were split into subgroups based on their tumor invasiveness profiles. In this analysis, tumors were classified as nodular, moderately diffuse, or highly diffuse. RESULTS A total of 101 patients were included. Tumors were classified as nodular (n = 34), moderately diffuse (n = 34), and highly diffuse (n = 33). On multivariate analysis, increasing SMR had a significant positive correlation with OS for moderately and highly diffuse tumors (HR 0.99, 95% CI 0.98–0.99; p = 0.02; and HR 0.98, 95% CI 0.96–0.99; p = 0.04, respectively). On threshold analysis, OS benefit was seen with SMR from 10% to 29%, 10% to 59%, and 30% to 90%, for nodular, moderately diffuse, and highly diffuse, respectively. CONCLUSIONS The impact of SMR on OS for patients with IDH–wild-type GBM is influenced by the degree of tumor invasiveness. The authors’ results show that increasing SMR is associated with increased OS in patients with moderate and highly diffuse IDH–wild-type GBMs. When grouping SMR into 10% intervals, this benefit was seen for all tumor subgroups, although for nodular tumors, the maximum beneficial SMR percentage was considerably lower than in moderate and highly diffuse tumors.