Subcortical Stimulation with Tip of Ultrasound Aspirator

Background During resection of intrinsic brain tumors in eloquent areas, particularly under awake mapping, subcortical stimulation is mandatory to avoid irreversible deficits by damaging white fiber tracts. The current practice is to alternate between subcortical stimulation with an appropriate probe and resection of tumoral tissue with an ultrasound aspiration device. Switching between different devices induces supplementary movement and possible tissue trauma, loss of time, and inaccuracies in the localization of the involved area. Objective To use one device for both stimulation as well as a resecting tool. Methods The tip of different ultrasound aspiration devices is currently used for monopolar current transmission (e.g., for vessel coagulation in liver surgery). We use the same circuitry for monopolar subcortical stimulation when connected with the usual stimulator devices. Results We have applied this method since 2004 in over 500 patients during tumor resection with cortical and subcortical stimulation, mostly with awake language and motor monitoring. Conclusion A method is presented using existing stimulation and wiring devices by which simultaneous subcortical stimulation and ultrasonic aspiration are applied with the same tool. The accuracy, safety, and speed of intrinsic intracranial lesion resection can be improved when subcortical stimulation is applied.

Diagnostic accuracy of prehospital serum S100B and GFAP in patients with mild traumatic brain injury: a prospective observational multicenter cohort study – “the PreTBI I study”

Background The biomarker serum S100 calcium-binding protein B (S100B) is used in in-hospital triage of adults with mild traumatic brain injury to rule out intracranial lesions. The biomarker glial fibrillary acidic protein (GFAP) is suggested as a potential diagnostic biomarker for traumatic brain injury. The aim of this study was to investigate the diagnostic accuracy of early prehospital S100B and GFAP measurements to rule out intracranial lesions in adult patients with mild traumatic brain injury. Methods Prehospital and in-hospital blood samples were drawn from 566 adult patients with mild traumatic brain injury (Glasgow Coma Scale Score 14–15). The index test was S100B and GFAP concentrations. The reference standard was endpoint adjudication of the traumatic intracranial lesion based on medical records. The primary outcome was prehospital sensitivity of S100B in relation to the traumatic intracranial lesion. Results Traumatic intracranial lesions were found in 32/566 (5.6%) patients. The sensitivity of S100B > 0.10 μg/L was 100% (95%CI: 89.1;100.0) in prehospital samples and 100% (95% CI 89.1;100.0) in in-hospital samples. The specificity was 15.4% (95%CI: 12.4;18.7) in prehospital samples and 31.5% (27.5;35.6) in in-hospital samples. GFAP was only detected in less than 2% of cases with the assay used. Conclusion Early prehospital and in-hospital S100B levels < 0.10 μg/L safely rules out traumatic intracranial lesions in adult patients with mild traumatic brain injury, but specificity is lower with early prehospital sampling than with in-hospital sampling. The very limited cases with values detectable with our assay do not allow conclusions to be draw regarding the diagnostic accuracy of GFAP. Trial registration ClinicalTrials.gov identifier: NCT02867137.

Multiple Cephalic Malformations in a Calf

Congenital malformations of the central nervous system (CNS) can affect the CNS alone or the CNS and craniofacial structures. Here, we report an unusual and complex congenital cephalic malformation observed in a 3-day-old male crossbreed calf. Clinical examination disclosed a dome-shaped cranial vault, a flat face with a short snout, a median cleft lip, and increased intraorbital distance. The frontal region of the head was remarkable for a fluctuant, sac-like protrusion covered with haired skin. Neurologic findings suggested a multifocal intracranial lesion affecting the prosencephalon and the central vestibular system. While pathological and histopathological findings posited for a presumptive diagnosis of either hydranencephaly or holoprosencephaly associated with multiple congenital facial abnormalities, not all the findings could be definitely attributed to either of the two encephalic malformations alone. To our knowledge, a similar combination of severe congenital abnormalities affecting both the CNS and the craniofacial structures has not been reported in calves to date.

Direct and transsynaptic retrograde degeneration and optic nerve head microvascular changes in patients with hemianopia

Purpose: To investigate optic nerve head (ONH) microvascular changes secondary to transsynaptic retrograde degeneration (TRD), comperatively with direct retrograde degeneration and healthy controls. Methods: Patients with hemianopia due to intracranial lesion included in the study. Intracranial lesion was categorized by location: postgeniculate (causing TRD), chiasmal (causing direct retrograde degeneration). For the postgeniculate lesions, the eye on the same side of the lesion was defined as the ipsilateral eye and the eye on the opposite side as the contralateral eye. Optic disc microvasculature was evaluated with the help of optic coherence tomography angiography. Results: Sixteen eyes of 16 patients with chiasmal lesion, 28 eyes of 14 patients with postgeniculate lesion, and 30 eyes of 30 healthy subjects were included in the study. Ipsilateral eyes of the patients with postgeniculate lesion had decreased vessel density at the temporal sectors compatible with the affected nasal side of the visual field. Contralateral eyes showed no reduction of the vessel density at the affected nasal sectors. The eyes with chiasmal lesions had decreased vessel density at the peripapillary region and nasal half of the ONH compatible with temporal hemianopia. Vascular changes in the chiasmal lesion were more prominent than those of the postgeniculate lesion. Retinal nerve fiber layer and ganglion cell complex thickness were reduced. Conclusion: Vessel density of ONH was reduced in patients with homonymous hemianopia, providing evidence for TRD secondary to acquired postgeniculate lesion. Direct retrograde degeneration was more prominent in affected sectors when compared to TRD.