Augmented reality–assisted microsurgical resection of brain arteriovenous malformations: illustrative case

Background: Arteriovenous malformations (AVMs) of the brain are vessel conglomerates of feeding arteries and draining veins that carry a risk of spontaneous and intraoperative rupture. Augmented reality (AR)-assisted neuronavigation permits continuous, real-time, updated visualization of navigation information through a heads-up display, thereby potentially improving the safety of surgical resection of AVMs. Observations: The authors report a case of a 37-year-old female presenting with a 2-year history of recurrent falls due to intermittent right-sided weakness and increasing clumsiness in the right upper extremity. Magnetic resonance imaging, magnetic resonance angiography, and cerebral angiography of the brain revealed a left parietal Spetzler-Martin grade III AVM. After endovascular embolization of the AVM, microsurgical resection using an AR-assisted neuronavigation system was performed. Postoperative angiography confirmed complete obliteration of arteriovenous shunting. The postsurgical course was unremarkable, and the patient remains in excellent health. Lessons: Our case describes the operative setup and intraoperative employment of AR-assisted neuronavigation for AVM resection. Application of this technology may improve workflow and enhance patient safety

The unruptured intracranial aneurysm treatment score A multidisciplinary consensus

Objective: We endeavored to develop an unruptured intracranial aneurysm (UIA) treatment score (UIATS) model that includes and quantifies key factors involved in clinical decision-making in the management of UIAs and to assess agreement for this model among specialists in UIA management and research. Methods: An international multidisciplinary (neurosurgery, neuroradiology, neurology, clinical epidemiology) group of 69 specialists was convened to develop and validate the UIATS model using a Delphi consensus. For internal (39 panel members involved in identification of relevant features) and external validation (30 independent external reviewers), 30 selected UIA cases were used to analyze agreement with UIATS management recommendations based on a 5-point Likert scale (5 indicating strong agreement). Interrater agreement (IRA) was assessed with standardized coefficients of dispersion (v(r)*) (v(r)* 5 0 indicating excellent agreement and v(r)* = 1 indicating poor agreement). Results: The UIATS accounts for 29 key factors in UIA management. Agreement with UIATS (mean Likert scores) was 4.2 (95% confidence interval [CI] 4.1-4.3) per reviewer for both reviewer cohorts; agreement per case was 4.3 (95% CI 4.1-4.4) for panel members and 4.5 (95% CI 4.3-4.6) for external reviewers (p = 0.017). Mean Likert scores were 4.2 (95% CI 4.1-4.3) for interventional reviewers (n = 56) and 4.1 (95% CI 3.9-4.4) for noninterventional reviewers (n = 12) (p = 0.290). Overall IRA (v(r)*) for both cohorts was 0.026 (95% CI 0.019-0.033). Conclusions: This novel UIA decision guidance study captures an excellent consensus among highly informed individuals on UIA management, irrespective of their underlying specialty. Clinicians can use the UIATS as a comprehensive mechanism for indicating how a large group of specialists might manage an individual patient with a UIA.Peer reviewe

Gender influences the initial impact of subarachnoid hemorrhage: an experimental investigation.

Aneurysmal subarachnoid hemorrhage (SAH) carries high early patient mortality. More women than men suffer from SAH and the average age of female SAH survivors is greater than that of male survivors; however, the overall mortality and neurological outcomes are not better in males despite their younger age. This pattern suggests the possibility of gender differences in the severity of initial impact and/or in subsequent pathophysiology. We explored gender differences in survival and pathophysiology following subarachnoid hemorrhage induced in age-matched male and female rats by endovascular puncture. Intracranial pressure (ICP), cerebral blood flow (CBF), blood pressure (BP) and cerebral perfusion pressure (CPP) were recorded at and after induction of SAH. Animals were sacrificed 3 hours after lesion and studied for subarachnoid hematoma size, vascular pathology (collagen and endothelium immunostaining), inflammation (platelet and neutrophil immunostaining), and cell death (TUNEL assay). In a second cohort, 24-hour survival was determined. Subarachnoid hematoma, post-hemorrhage ICP peak, BP elevation, reduction in CPP, intraluminal platelet aggregation and neutrophil accumulation, loss of vascular collagen, and neuronal and non-neuronal cell death were greater in male than in female rats. Hematoma size did not correlate with the number of apoptotic cells, platelet aggregates or neutrophil. The ICP peak correlated with hematoma size and with number of apoptotic cells but not with platelet aggregates and neutrophil number. This suggests that the intensity of ICP rise at SAH influences the severity of apoptosis but not of inflammation. Mortality was markedly greater in males than females. Our data demonstrate that in rats gender influences the initial impact of SAH causing greater bleed and early injury in males as compared to females

Cerebrospinal Fluid Leaks of Temporal Bone Origin: Selection of Surgical Approach

Cerebrospinal fluid leaks of the temporal bone are rare, often occult, and sometimes challenging to localize and repair. This is a retrospective study of eight patients with spontaneous cerebrospinal fluid leak and six patients with cerebrospinal fluid leak or encephalocele discovered during chronic ear surgery who were treated in a tertiary medical center over a 5-year period. All received preoperative temporal bone computed tomography, and six also underwent magnetic resonance imaging, one computed tomography cisternography, and one radionuclide cisternography. All patients initially underwent a transmastoid surgical approach. Additional exposure was necessary in three patients; two underwent middle fossa craniotomy and another required minicraniotomy. Primary surgical repair was successful in six of the eight patients with spontaneous leaks and in all six chronic ear patients. Both recurrences required intradural middle fossa repair. An individualized approach should be taken for repair of temporal bone cerebrospinal fluid leaks. In this series, most were successfully repaired in a single stage using a transmastoid or combined approach. The transmastoid approach provides information about the precise size and location of the dural defect. A primary transcranial approach is needed for defects that are multiple, located in the petrous apex, and in revision cases

Vascular pathology.

<p>Cerebral vessels of animals sacrificed 3 hours after SAH. Panel A: representative images of ICA from a single male and a single female rat. Panel B: average vessel sizes. Note that the internal circumference of ICA in SAH males is smaller compared to females. Panel C: representative images showing brain vessels stained for platelets, RECA-1 (an endothelium marker), and collagen-IV (a basal lamina marker); note the greater numbers of RECA-1 and collagen IV stained vessels containing platelet aggregates (arrows) in males. Panel D: average area fractions of RECA-1 and collagen-IV positive vascular profiles of SAH animals as percent changes over sham-operated cohorts. The reduction in the area fraction of RECA-1 is similar in males and females but that of collagen -IV is different. Data are mean ± sem from 5 animals per gender. * significantly difference than females (p <0.01).</p

Cell death.

<p>Activated caspase-3 immunoreactivity and TUNEL staining 3h after SAH. Panels A-B: 4-color fluorescence staining for TUNEL, NeuN, collagen-IV, and DAPI. Panel A: typical micrographs from male and female SAH animals. Each channel is shown as a separate image. Small arrows: TUNEL-positive neurons; large arrowheads: TUNEL-positive vascular cells. Note the greater frequency of TUNEL-positive neurons in male as compared to female. Panel B: average numbers of TUNEL-only, TUNEL+NeuN, and TUNEL+collagen-IV profiles. TUNEL-only and TUNEL-NeuN profiles are significantly greater in males than in females. Panel C: average numbers of profiles positive for activated caspase-3 (Cas) only, Cas+NeuN, and Cas+collagen-IV. All three indexes are significantly greater in male animals. Panel D: Fluoro-Jade B-positive cells (arrows) in representative SAH male and female brain sections. Panel E: Average numbers of Fluoro-Jade B-positive cells in SAH animals. Data are mean ± sem from 5 animals per gender. * significantly gender difference (p <0.05). </p

Correlation analysis.

<p>The association of ICP peak values with numbers of platelet aggregates (A), neutrophils (B), and apoptotic cells (C). The ICP peak significantly correlated with the number of apoptotic cells but not with the numbers of platelet aggregates or neutrophils. Each point is the mean from a single animal.</p

Subarachnoid hematoma.

<p>Panel A: representative images of subarachnoid blood in male and female rats at 3 hours after SAH. Subarachnoid clots (outlined in white in the images) exhibit a characteristic granular immunofluorescence for RECA-1 and are both surrounded by and infiltrated by neutrophils. In general, individual clots in males were larger and clots in females were smaller. ON: optic nerve; scale bar = 200 μm Panel B: the summed areas of subarachnoid blood were determined by tracing. The accumulated data show areas larger in males than in females, a trend which did not reach significance (p=0.4). Data are mean ± sem from 5 animals per gender. Cryostat sections from animals sacrificed at 3 hours after SAH and immunofluorescent for RECA-1 and neutrophils (HB-199) were used for this determination. As stated in Methods, the perfusion fixation procedure employed caused subarachnoid blood to adhere to the brain surface during removal of brains from the cranium. The grayscale images combine signals from two color channels.</p

Cerebral inflammation.

<p>Luminal platelet aggregates and neutrophil accumulation in animals sacrificed 3 hours after SAH. Panel A: representative images of neutrophil staining. Note the greater number of neutrophils in male as compared to female brain. Scale bar = 500 μm. Panels B, C: average numbers of neutrophils and vascular platelet aggregates per whole brain section and per image field, respectively. Both parameters are greater in male as compared to female brains. Data are mean ± sem from 5 animals per gender. * significantly difference than females (p <0.05).</p