Cerebral venous thrombosis is a clinical entity which is readily diagnosed with the advent of modern imaging techniques. Anticoagulation is now a standard therapy, but more recent treatment strategies have included endovascular thrombolysis. While the endpoint of this intervention both clinically and radiographically has not been defined, noninvasive monitoring techniques may add further objective measures of treatment response.

We present a patient with a four day history of worsening headache and papilledema on exam. Superior sagittal, straight, and bilateral transverse sinus thromboses were identified on computed tomography and angiography.

Emergent endovascular thrombolysis by a transvenous approach re-established venous patency and resulted in immediate resolution of the patient's symptoms. Cerebral oximetry by near-infrared spectroscopy was utilized during the procedure, and changes in chromophore concentrations correlated directly with angiographic and clinical resolution of the thrombosis.

Near-infrared spectroscopy can provide continuous feedback during thrombolytic therapy in cerebral venous thrombosis and may help define endpoints of such intervention.

Brainstem auditory evoked potentials (BAEP) are useful indicators of auditory function during posterior fossa surgery. Several potential mechanisms of injury may affect the cochlear nerve, and complete loss of BAEP is often associated with postoperative hearing loss. We report two cases of intraoperative auditory loss related to vascular compression upon the cochlear nerve.

Intra-operative BAEP were monitored in a consecutive series of over 300 microvascu-lar decompressions (MVD) performed in a recent twelve-month period. In two patients undergoing treatment for trigeminal neuralgia, BAEP waveforms suddenly disappeared completely during closure of the dura.

The cerebello-pontine angle was immediately re-explored and there was no evidence of hemorrhage or cerebellar swelling. The cochlear nerve and brainstem were inspected, and prominent vascular compression was identified in both patients. A cochlear nerve MVD resulted in immediate restoration of BAEP, and both patients recovered without hearing loss.

These cases illustrate that vascular compression upon the cochlear nerve may disrupt function, and is reversible with MVD. Awareness of this event and recognition of BAEP changes alert the neurosurgeon to a potential reversible cause of hearing loss during posterior fossa surgery.

We aimed to interrogate the Canadian Institute for Health Information (CIHI) database in order to determine the geographic distribution and outcomes of microvascular decompression (MVD) for the treatment of hemifacial spasm (HFS).

The CIHI database was searched from 2004 to 2017 for relevant diagnostic and procedure codes. A new database was populated with the following categories: year, institution, province, number of interventions per year, and mean length of stay. Descriptive statistics were generated. Provincial utilization rates of MVD for HFS were calculated.

During the period 2004-17, we identified 671 MVDs performed for HFS at 20 centers across Canada. During the study period, 286 MVDs (42.6%) were performed at one center in Manitoba. Another 131 (19.5%) and 72 (10.7%) were performed at one center in British Columbia and Ontario, respectively. The remaining 182 (27.1%) MVDs for HFS were performed at 17 centers across the rest of Canada where the mean number of cases performed per year was 1.1 (SD=0.9, range 0.2-2.9). When out-of-province cases were re-allocated to place of residence, the adjusted provincial utilization of MVD for HFS ranged between 0.5 and 6.1 patients per million per year.

Microvascular decompression for HFS is performed relatively rarely and there is a tremendous geographic variation in utilization across Canada. Although most of these surgeries are performed by a few surgeons, more than half of Canadian centers perform an average of less than 1 case per year. Further examination of the impact of these discrepancies appears warranted.

The treatment of unruptured, intracranial aneurysms has been the topic of debate. Although recent studies have advocated surgical intervention for unruptured aneurysms, the risk of such treatment in comparison to outcome from ruptured aneurysms has not been established.

This retrospective study examines the outcome of 134 patients with 179 ruptured and unruptured intracranial, saccular aneurysms treated by a single surgeon.

Of the 98 ruptured aneurysms where early surgical intervention was undertaken (less than 48 hours post hemorrhage), 70 had an excellent outcome, 13 were good, four were moderate, two poor and nine patients died postoperatively. Outcome assessment in these cases was correlated to preoperative neurological status. Patients who presented with unruptured aneurysms fell into two categories: symptomatic and asymptomatic. Seven incidental, asymptomatic aneurysms were clipped concurrently to the surgical isolation of the culprit lesion following subarachnoid hemorrhage without influencing outcome, whilst, for varying reasons, eight unruptured aneurysms were not operated upon. Of the remaining 66 surgically treated, unruptured aneurysms, 64 had an excellent postoperative result, one was good (persisting right incomplete third nerve palsy) and one was moderate (left hemiparesis). Thirteen of these aneurysms were symptomatic, whilst 21 were asymptomatic, multiple aneurysms requiring secondary elective repair and 32 were true incidental aneurysms.

Unruptured aneurysms less than 25 mm in size may be safely, surgically treated relative to the expected natural history and, certainly, with less risk than operative intervention upon ruptured cerebral aneurysms.

Infection related to external ventricular drain (EVD) use is a common neurosurgical complication. Modified catheters with a hydrophilic surface may impede bacterial adherence and thereby reduce catheter related cerebrospinal fluid (CSF) infection.

A prospective randomized clinical trial compared the occurrence of CSF infection related to use of either standard silastic or hydrogel coated EVD catheters (Bioglide®, Medtronic). Enrolment was available to all adult neurosurgery patients undergoing placement of a first EVD, at three university centers. The catheters were presoaked in a low concentration of bacitracin solution for 5-10 minutes prior to insertion. Bacterial infection was defined by heavy growth in a single CSF sample or light / medium growth in two consecutive samples. A secondary analysis was also conducted for “probable” CSF infection, including patients started on antibiotics after light / medium growth in a single CSF sample. Statistical analyses included Kaplan-Meier survival curve estimates accompanied by Log Rank and Breslow tests.

There were 158 randomized patients available to assess for EVD related infection of CSF. The two study groups had similar clinical characteristics including average duration of EVD use (8±4 days). Definite CSF infection occurred in seven and probable infection in another six (8% total). Infection incidence rose steadily from day 2 (1%) to day 11 (11%). There was no difference of daily occurrence of EVD infection between the two catheter types.

Infection remains a common hazard in the use of EVD, and we found no reduction of infection using the hydrogel-coated catheters when presoaked in low concentration bacitracin solution.

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.

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.

Fifteen patients with intracerebral hemorrhage received 40-90 μg/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).

The pre or peri-operative administration of rFVIIa resulted in minimal residual or recurrent hematoma volume and may be an important adjunct to surgery in patients with intracerebral hemorrhage.

Hemifacial spasm (HFS) may be due to peripheral axon ephapsis or central motor neuron hyperexcitability. Low facial motor evoked potential (MEP) thresholds or MEP responses to single pulse stimulation (normally multipulse stimulation is needed) may support the central hypothesis.

We retrospectively compared response thresholds for facial MEPs in 65 patients undergoing surgical microvascular decompression (MVD) for HFS and 29 patients undergoing surgery for skull base tumors.

Single pulse stimulation elicited facial Mep in up to 87% of HFS patients whereas only 10% of tumor patients responded to single pulse stimulation. When comparing facial MEP thresholds using multi-pulse stimulus trains the voltage required in the HFS group were significantly lower then in skull base tumor patients (p < 0.001). the MEP latencies and amplitudes at threshold stimulation were similar between the two groups.

these results suggest the facial corticobulbar pathway demonstrates enhanced excitability in HFS.