Clinical Outcome and Recurrence Risk of Chronic Subdural Hematoma After Surgical Drainage.

Introduction Chronic subdural hematoma (CSDH) is one of the most encountered neurosurgical cases. CSDH is defined as the accumulation of liquified blood products in the space between the dura and the arachnoid. A reported incidence of 17.6/100,000/year has more than doubled in the past 25 years in parallel with an aging population. Surgical drainage remains the mainstay of treatment, yet it is challenged by variable recurrence risks. Less invasive embolization methods of the middle meningeal artery (EMMA) could reduce the recurrence risks. Before adopting a newer treatment (EMMA), it is prudent to establish the outcomes from surgical drainage. The purpose of this study is to assess the clinical outcome and recurrence risk in surgically treated CSDH patients in our center. Methods A retrospective search of our surgical database was done to identify CSDH patients undergoing surgical drainage in the year 2019-2020. Demographic and clinical details were collected, and quantitative statistical analysis was performed. Peri-procedural radiographic information and follow-ups were also included as per the standard of care. Results A total of 102 patients (mean age: 69 years; range: 21-100 years; male: 79) with CSDH underwent surgical drainage with repeat surgery in 13.7% of the patients (n=14). Peri-procedural mortality and morbidity were 11.8%(n=12) and 19.6% (n=20), respectively. Overall, among our patient population, recurrence was seen in 22.55% (n=23). The mean total hospital stay was 10.6 days. Conclusions Our retrospective cohort study showed an institutional CSDH recurrence risk of 22.55%, in keeping with what is reported in the literature. This baseline information is important for a Canadian setting and provides a basis for comparison for future Canadian trials.

Cathodal Genesis of Ipsilateral Hand (Crossover) Motor Evoked Potentials: Evidence from a Patient with Previous Stroke.

A case is described where baseline transcranial electrical motor evoked potentials (TcMEP) and somatosensory evoked potentials (SSEP) results were unilaterally absent in a patient with previous hemispheric stroke undergoing a right-sided carotid endarterectomy. SSEP data confirmed right cortical pathology and excluded a technical rationale for absent motor evoked responses. Attempts at generating left-hand (contralateral) TcMEP from right cortical anodal stimulation failed despite high stimulus intensities. However, TcMEP responses from anodal stimulation of the right cortex were recorded from the right-hand (ipsilateral) which were attributed to "crossover." Ipsilateral TcMEP onset latencies derived from the stimulus-response data supports the idea that crossover is a product of cathodal stimulation initially acting on pericortical motor pathways.

Transvenous Embolization of Dural Arteriovenous Fistulas with Cortical Venous Drainage.

Dural arteriovenous fistulas (DAVFs) are direct shunts between extracranial or meningeal arteries and dural sinuses, dural veins, or cortical veins. They account for 10%-15% of all intracranial vascular malformations. DAVFs are classified according to two classification systems, Borden and Cognard, both of which are based on the venous drainage pathway and presence of antegrade or retrograde venous flow. A multidisciplinary approach using endovascular techniques has become the mainstay of treatment. We present two cases of DAVF with cortical venous drainage (Borden type 3) that were successfully treated using a transvenous approach via the draining subarachnoid veins.

Cerebral revascularization in cerebral proliferative angiopathy: a systematic review.

OBJECTIVECerebral proliferative angiopathy (CPA) is considered a discrete vascular malformation of the brain separate from classical brain arteriovenous malformations (AVMs). It has unique angiographic characteristics and has been hypothesized to result from chronic cortical ischemia and perinidal oligemia. Treatment with cerebral revascularization has been proposed in an attempt to disrupt regional hypoperfusion and interrupt the angiogenesis that defines CPA. A systematic review of the literature pertaining to the role of cerebral revascularization may highlight a treatment paradigm for this rare disease.METHODSA systematic review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. MEDLINE and Embase were searched from inception for papers relating to CPA. Included articles were categorized according to methodology (case series or imaging study) and treatment modality (conservative, radiation, endovascular, or revascularization). A synthesis was compiled summarizing the current evidence regarding cerebral revascularization in CPA.RESULTSThe initial search revealed 43 articles, of which 28 studies met the inclusion criteria. Nine studies were identified that described imaging findings, which suggested hemodynamic dysregulation and perinidal impairments in the cerebrovascular reserve could be identified compared to unaffected hemispheres and classical brain AVMs. Six studies including 7 patients undergoing indirect forms of cerebral revascularization were identified. Clinical and radiological outcomes following revascularization were favorable in all but one study.CONCLUSIONSA small body of radiological and clinical studies has emerged, suggesting that CPA is a response to perinidal oligemia. While the long-term clinical efficacy of revascularization remains unclear, early results suggest that this may be a novel treatment paradigm for patients with CPA.

Cerebral cavernous malformations and pregnancy: hemorrhage risk and influence on obstetrical management.

BACKGROUND: Cerebral cavernous malformations are brain vascular malformations associated with intracranial hemorrhage. It is unclear whether pregnancy is a risk factor for hemorrhage, yet there is speculation that it may be. OBJECTIVE: To compare the risk of clinically significant hemorrhage during pregnancy and nonpregnancy. METHODS: A total of 186 patients from the University of Toronto Vascular Malformations Study Group were enrolled. The obstetrical history of each patient was collected and matched to their neurological history from the records of the study group. All hemorrhagic events occurring during childbearing years were associated with either a defined pregnancy risk period or nonpregnancy period. Patients were also asked to recall advice that they received from health care professionals regarding risk of hemorrhage in pregnancy. RESULTS: Among our patient population there were 349 pregnancies (283 live births) and 49 hemorrhages during childbearing years, 3 of which were during pregnancy but none during delivery or within 6 weeks post partum. The hemorrhage rate for pregnant women was 1.15% (95% confidence interval: 0.23-3.35) per person-year and 1.01% (95% confidence interval: 0.75-1.36) per person-year for nonpregnant women. Relative risk of pregnancy was 1.13 (95% confidence interval: 0.34-3.75) (P = .84). Neurosurgeons and obstetricians were the source of most hemorrhage risk advice. The majority of neurosurgeons suggested that the risk was unchanged, but the obstetricians were divided. Four patients never conceived, and 2 others began contraception because of the advice that they received. CONCLUSION: The risk of intracranial hemorrhage from cerebral cavernous malformations is likely not changed during pregnancy, delivery, or post partum.

Lactate flux during carotid endarterectomy under general anesthesia: correlation with various point-of-care monitors.

PURPOSE: The ability to assess the brain-at-risk during carotid endarterectomy (CEA) under general anesthesia remains a major clinical problem. Point-of-care monitoring can potentially dictate changes to management intraoperatively. In this observational study, we examined the correlation between a series of point-of-care monitors and lactate flux during CEA. METHODS: Both neurosurgeons and vascular surgeons participated in the study. The patients underwent arterial-jugular venous blood sampling for oxygen, carbon dioxide, glucose, and lactate, n = 26; bispectral index (BIS) monitoring ipsilateral to side of surgery, n = 26; raw and processed electroencephalogram (EEG), n = 22; and bi-frontal cerebral oximetry using the Fore-Sight monitor, n = 20. RESULTS: One patient experienced a new neurological deficit when assessed at 24 hr following surgery. Lactate flux into the brain was correlated with the greatest decrease in cerebral oximetry with carotid cross-clamping; lactate efflux was correlated with the least. The most noticeable changes in processed EEG (density spectral analysis) were also seen with lactate influx, but at a slower time resolution than cerebral oximetry. Loss of autoregulatory behaviour was demonstrated with lactate influx; however, no correlation was seen between lactate flux and BIS monitoring. CONCLUSION: There was a correlation between cerebral oximetry and lactate flux during carotid cross-clamping. The Fore-Sight monitor may be of value as a point-of-care monitor during CEA under general anesthesia. A novel finding of this study is lactate flux into the brain in the presence of a large difference in cerebral oxygenation during cross-clamping of the carotid artery. Registered at clinicaltrials.gov: NCT000737334.

A comparison of the ability of the EEGo and BIS monitors to assess emergence following neurosurgery.

PURPOSE: Deep anesthesia during microvascular decompression (MVD) for trigeminal neuralgia and cerebral aneurysm clipping may delay emergence. A new electroencephalographic (EEG) monitor, the EEGo, processes a raw EEG signal using time-delay analysis to display a reproducible signal transition from deep anesthesia through the excitement state to the awake state. We hypothesized that the EEGo monitor would be superior to the bispectral (BIS) monitor, not only in aiding emergence but also in detecting sudden changes in levels of hypnosis. METHODS: Twenty-one patients undergoing neurosurgery were studied (16 MVD, 5 cerebral aneurysm clipping). Each patient had both EEGo and BIS monitoring with only one monitor available for viewing by the anesthesiologist. The anesthetic was titrated based on the available monitor, and the time to emergence was measured. Intraoperative detection of arousal and the timing of burst suppression during propofol administration were also examined. RESULTS: In the MVD patients, there was no statistical difference in wake-up times between the EEGo and BIS groups. Additionally, there were no episodes of intraoperative awareness and no differences in patient satisfaction. Compared to EEGo waveform output, a decrease in BIS output was delayed in four patients receiving propofol for burst suppression during cerebral aneurysm clipping, indicating enhanced hypnosis. One case of intraoperative arousal, which occurred at a BIS reading of 43 arbitrary BIS units, was detected earlier with the EEGo. CONCLUSIONS: While the EEGo was faster than the BIS at indicating planned changes in levels of hypnosis throughout propofol administration prior to temporary clipping during aneurysm surgery, the EEGo was not superior to the BIS monitor in facilitating a more rapid emergence following neurosurgery.

Recombinant factor VIIa plus surgery for intracerebral hemorrhage.

BACKGROUND: Hyperacute surgical evacuation of intracerebral hemorrhage is associated with a high rebleeding rate. The peri-operative administration of rFVIIa to patients with intracerebral hemorrhage may decrease the frequency of post-operative hemorrhage, and improve outcome. METHODS: Patients receiving recombinant activated factor VII (rFVIIA) therapy immediately prior to acute surgery were collected at two centres. The intracerebral hemorrhage (ICH) score and ICH Grading Scale were determined, as was long-term outcome using the modified Rankin Scale. Residual/recurrent clot was evaluated by comparing pre-operative to post-operative CT scans. RESULTS: Fifteen patients with intracerebral hemorrhage received 40-90 microg/kg of rFVIIa and underwent surgical hematoma evacuation at a median time of five hours following symptom onset. Median pre-operative clot volume was 60 ml, decreasing to 2 ml post-operatively. There were no thromboembolic adverse events. Thirteen patients survived, 11 (73%) were independent, and two (13%) had a moderate to severe disability. These outcomes were significantly better than expected based on the median ICH score (40% mortality) and based on median ICH Grading Scale (18% good outcome). CONCLUSIONS: The pre or perioperative administration of rFVIIa resulted in minimal residual or recurrent hematoma volume and may be an important adjunct to surgery in patients with intracerebral hemorrhage.