Showing papers by "Karol P. Budohoski published in 2018"

Transcranial Doppler: a stethoscope for the brain-neurocritical care use.

Abstract: Transcranial Doppler (TCD) ultrasonography is a noninvasive bedside monitoring technique that can evaluate cerebral blood flow hemodynamics in the intracranial arterial vasculature. TCD allows assessment of linear cerebral blood flow velocity, with a high temporal resolution and is inexpensive, reproducible, and portable. The aim of this review is to provide an overview of the most commonly used TCD derived signals and measurements used commonly in neurocritical care. We describe both basic (flow velocity, pulsatility index) and advanced concepts, including critical closing pressure, wall tension, autoregulation, noninvasive intracranial pressure, brain compliance, and cerebrovascular time constant; we also describe the clinical applications of TCD to highlight their utility in the diagnosis and monitoring of cerebrovascular diseases as the "stethoscope for the brain."

Predictors of early progression of surgically treated atypical meningiomas.

Abstract: Clinical behaviour of atypical meningiomas is not uniform. While, as a group, they exhibit a high recurrence rate, some pursue a more benign course, whereas others progress early. We aim to investigate the imaging and pathological factors that predict risk of early tumour progression and to determine whether early progression is related to outcome. Adult patients with WHO grade II meningioma treated in three regional referral centres between 2007 and 2014 were included. MRI and pathology characteristics were assessed. Gross total resection (GTR) was defined as Simpson 1–3. Recurrence was classified into early and late (≤ 24 vs. > 24 months). Among the 220 cases, 37 (16.8%) patients progressed within 24 months of operation. Independent predictors of early progression were subtotal resection (STR) (p = 0.005), parafalcine/parasagittal location (p = 0.015), peritumoural oedema (p = 0.027) and mitotic index (MI) > 7 (p = 0.007). Adjuvant radiotherapy was negatively associated with early recurrence (p = 0.046). Thirty-two per cent of patients with residual tumour and 26% after GTR received adjuvant radiotherapy. There was a significantly lower proportion of favourable outcomes at last follow-up (mRS 0–1) in patients with early recurrence (p = 0.001). Atypical meningiomas are a heterogeneous group of tumours with 16.8% patients having recurrence within 24 months of surgery. Residual tumour, parafalcine/parasagittal location, peritumoural oedema and a MI > 7 were all independently associated with early recurrence. As administration of adjuvant radiotherapy was not protocolised in this cohort, any conclusions about benefits of irradiation of WHO grade II meningiomas should be viewed with caution. Patients with early recurrence had worse neurological outcome. While histological and imaging characteristics provide some prognostic value, further molecular characterisation of atypical meningiomas is warranted to aid clinical decision making.

Baroreflex Impairment After Subarachnoid Hemorrhage Is Associated With Unfavorable Outcome

Abstract: Background and Purpose— Aneurysmal subarachnoid hemorrhage (SAH) is characterized by important changes in the autonomic nervous system with potentially adverse consequences. The baroreflex has a key role in regulating the autonomic nervous system. Its role in SAH outcome is not known. The purpose of this study was to evaluate the association between the baroreflex and the functional 3-month outcome in SAH. Methods— The study used a prospective database of 101 patients hospitalized for SAH. We excluded patients receiving β-blockers or noradrenaline. Baroreflex sensitivity (BRS) was measured using the cross-correlation method. A good outcome was defined by a Glasgow Outcome Scale score at 4 or 5 at 3 months. Results— Forty-eight patients were included. Median age was 58 years old (36–76 years); women/men: 34/14. The World Federation of Neurosurgery clinical severity score on admission was 1 or 2 for 73% of patients. In the univariate analysis, BRS ( P =0.007), sedation ( P =0.001), World Federation of Neurosurgery score ( P =0.001), Glasgow score ( P =0.002), Fisher score ( P =0.022), and heart rate ( P =0.037) were associated with outcome. The area under the receiver operating characteristic curve for the model with BRS as a single predictor was estimated at 0.835. For each unit increase in BRS, the odds for a good outcome were predicted to increase by 31%. Area under the receiver operating characteristic curve for heart rate alone was 0.670. In the multivariate analysis, BRS (odds ratio, 1.312; 95% confidence interval, 1.048–1.818; P =0.018) and World Federation of Neurosurgery (odds ratio, 0.382; 95% confidence interval, 0.171–0.706; P =0.001) were significantly associated with outcome. Area under the receiver operating characteristic curve was estimated at 0.900. Conclusions— In SAH, early BRS was associated with 3-month outcome. This conclusion requires confirmation on a larger number of patients in a multicentre study.

Simultaneous navigated cervico-thoracic and thoraco-lumbar fixation.

Abstract: Case report. To investigate the feasibility of using two independent image guidance systems to simultaneously fix multiple segment spine fractures. Image guidance is increasingly used to aid spinal fixation. We describe the first use of multiple navigation systems during a single procedure allowing for multi-segment spinal fixations to be performed simultaneously and capitalizing the advantages of navigation. Two Medtronic Stealth Station S7™ systems with O-arm image capture were used to guide fixation of C6 and T12, unstable, AO A4, three-column fractures, in a patient with ankylosing spondylitis. Two surgical teams were able to perform cervico-thoracic and thoraco-lumbar fixations simultaneously. Operative time was 2.5 h. Post-operative imaging showed accurate instrumentation placement. The patient recovered without any neurological sequelae. Optical independence of the Medtronic Stealth Station™ system allowed for simultaneous navigation guided fixation of multiple segment fractures without compromising accuracy. This may result in shortened operative time and morbidity associated with prolonged prone positioning of polytrauma patients, as well as reducing radiation exposure for theatre staff.

Effect of Mild Hypocapnia on Critical Closing Pressure and Other Mechanoelastic Parameters of the Cerebrospinal System

Abstract: Objective: Brain arterial critical closing pressure (CrCP) has been studied in several diseases such as traumatic brain injury (TBI), subarachnoid haemorrhage, hydrocephalus, and in various physiological scenarios: intracranial hypertension, decreased cerebral perfusion pressure, hypercapnia, etc. Little or nothing so far has been demonstrated to characterise change in CrCP during mild hypocapnia.

Microsurgical Resection of a Common Peroneal Nerve Schwannoma: A 3-Dimensional Operative Video.

Abstract: Peripheral nerve sheath tumors are benign entities that manifest with pain or neurological deficits from mass effect Treatment is mostly surgical, however, the aggressiveness of treatment needs to be carefully considered with respect to preserving function We present a case of a 62-year-old male with a 2-year history of left lower extremity pain radiating toward the dorsolateral foot There was a tender and palpable mass in the lateral popliteal fossa with imaging consistent with Schwannoma of the common peroneal nerve The patient was counseled for surgery and informed consent was obtained Microsurgical resection was undertaken and gross total resection was achieved without compromise of function We demonstrate the placement of neurophysiological monitoring electrodes in all 3 compartment of the calf as well as the use of stimulation to identify a nonfunctioning area for entering the nerve sheath Anatomy of the popliteal fossa and microsurgical technique for resection of nerve sheath tumors are discussed When dealing with these pathologies, it is important to use intraoperative neurophysiology as well as careful technique in order to achieve maximal resection without compromising neurological function

Growing Evidence: Dysautoregulation May Trigger Ischemic Deficit After Subarachnoid Hemorrhage.

Abstract: Copyright © 2018 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved. 828 www.ccmjournal.org May 2018 • Volume 46 • Number 5 Early brain injury (EBI) and delayed cerebral ischemia (DCI) have increasingly become the focus of attention in the management of aneurysmal subarachnoid hemorrhage (SAH) (1). Although clearly spectacular when it occurs, vasospasm can be held responsible for only a part of delayed ischemic complications. Clinically, patients with significant narrowing of large cerebral arteries and lack of clear symptoms of ischemia or vice versa can be seen. Indeed, whereas vasospasm can be picked up in nearly two thirds of patients, DCI occurs in less than a third (2). PET and CT perfusion studies show that the brain after SAH may be perfused as heterogeneously as seen after traumatic brain injury—with regions of ischemia and hyperemia that do not always match the vascular territory of the vessel harboring the aneurysm nor the spastic vessel (3). Numerous pathophysiologic mechanisms have been proposed to explain the phenomenon of DCI, loss of cerebral autoregulation, but also inflammatory reactions, necrosis/apoptosis, or cortical spreading depression. Loss of cerebral autoregulation in the early phase after ictus has been implicated in a number of studies and has been shown to be independently associated with DCI, delayed infarcts, as well as outcomes (2, 4–8). Failure of autoregulation following SAH fits well with the dual insult theory proposed by Harper and Glass (9), which states that two hemodynamic insults (e.g., vascular spasm and hypotension with preserved autoregulation or vascular spasm and autoregulatory failure) are needed to induce ischemia. With many patients after SAH, particularly poor grade, being treated on ICUs and hypotension exceedingly rare, dysautoregulation may significantly contribute to cerebral ischemia even in the context of normotension. Gaash et al (10), in their article published in this issue of Critical Care Medicine, present a study looking at two known autoregulatory indices: the pressure reactivity index (PRx) and the brain tissue Po 2 (P bt o 2 )–derived autoregulation index (ORx) and their relationship with DCI as well as outcome. PRx has not been previously studied in this context. Although the authors demonstrate a clear association of early abnormal PRx with DCI and outcome, they fail to reproduce the results of Jaeger et al (4, 5), who demonstrated the same relationship with ORx. The authors detected two distinct peaks of autoregulatory failure: one early, only visible in the DCI group and another delayed, visible in both groups of patients. Without more detailed physiologic studies, it cannot be determined with certainty, but the early peak can be related to the broadly understood EBI occurring after SAH, whereas the second peak seems to overlap with the typical time window of vasospasm. Indeed, as the authors point out the first peak of autoregulatory disturbance may simply be related to the severity of injury sustained from the ictus, similarly to what has been described after head injury (11). If true, this would be a very important indicator of the severity of injury, above that of the clinically determined World Federation of Neurosurgical Societies grade (which in the current form is a very crude measure, albeit used in decision-making, particularly with respect to timing of endovascular or surgical intervention). It is well recognized that the treatment outcomes for poor grade patients with SAH are suboptimal with significant vulnerability to vessels occlusion (balloon or catheter) when treated endovascularly or temporary clipping when treated surgically. Therefore, knowledge about the status of autoregulation could be important in the critical care management of patients with SAH and estimating the risk of DCI and outcome as suggested by the authors, but also it could play a role in choosing the best timing for intervention and reducing treatment-related ischemic complications. Although the study by Gaash et al (10) is well reported, it is worth mentioning that DCI is extremely difficult to diagnose in comatose patients, which are the subjects of their article. The classical definitions related to clinical deterioration do not apply due to the inability to reliably assess patients (12). Therefore, surrogates, such as perfusion deficits or spasm seen on angiography, are typically used missing the previously mentioned heterogeneity of DCI. Second, monitoring of PRx when external ventricular (EVD) drainage is open also raises methodologic question, as open EVD decreases slope of pressurevolume curve, potentially disrupting a link between slow waves in blood pressure and intracranial pressure (ICP). Despite its limitations, the study by Gaash et al (10) provides further evidence on the utility of monitoring autoregulation after SAH. However, before widely adopted in the treatment of SAH, more work needs to be done in order to elucidate the best methodologies. While PRx and ORx are appealing due to their continuous nature, relative ease of use (once patient has ICP and/ or P bt o 2 probes inserted, no further interventions are needed), it remains to be determined whether indices using measurements of blood flow, such as transcranial Doppler blood flow velocities, near-infrared spectroscopy, or thermal dilution cerebral blood flow measurements fare better. Furthermore, invasive monitoring is only available in a small subset of patients who present in coma, *See also p. 774.