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Same day discharge or outpatient surgery for intracranial procedures has become possible with the advent of image-guided minimally invasive approaches to surgery and availability of short-acting anesthetic agents. In addition, patient satisfaction and the benefits of avoiding hospital stay have resulted in the evolution of neurosurgical day surgery. We reviewed our experience and the available literature to determine the perioperative factors involved which have promoted and will improve this concept in the future. Craniotomy and biopsy for supratentorial brain tumors and surgical clipping of intact cerebral aneurysms have been successfully performed as day surgeries. Patient perceptions and satisfaction surveys have helped in better understanding and delivery of care and successful outcomes. There are major differences in health care across the globe along with socioeconomic, medicolegal, and ethical disparities, which must be considered before widespread application of this approach. Nevertheless, collaborative effort by surgeons, anesthesiologists, and nurses can help in same day discharge of patients after cranial neurosurgery.

BACKGROUND Stereotactic headframe-based imaging is often needed for target localization during surgery for insertion of deep brain stimulators. A major concern during this surgery is the need for emergency airway management while an awake or sedated patient is in the stereotactic headframe. The aim of our study was to determine the ease of emergency airway management with a stereotactic headframe in situ. MATERIALS AND METHODS We conducted an observational study using a mannequin. A Leksell stereotactic headframe was placed on a mannequin in the operating room and the frame was fixed to the operating room table. Anesthesia personnel were asked to insert a #4 laryngeal mask and then to intubate the mannequin, using both direct (DL) and video laryngoscopy (VL). In addition, participants were asked to perform the same airway techniques in the mannequin without the headframe. Data were analyzed for time taken for airway management using different devices with and without the headframe. In addition, we compared the time taken to secure the airway between different participant groups. RESULTS Thirty anesthesia personnel (7 residents, 12 fellows, and 11 consultants) participated in the study. With the headframe in situ, 97% of participants were able to insert a laryngeal mask on their first attempt; 93% and 97% of participants were able to intubate the mannequin using DL and VL respectively on their first attempt. Without the stereotactic headframe, all participants were able to insert the laryngeal mask and intubate on the first attempt. The average time taken to insert a laryngeal mask and intubate the mannequin using DL and VL with the headframe in situ was 39.3, 58.6, and 54.8 seconds, respectively. CONCLUSIONS Our study showed that both laryngeal mask insertion and tracheal intubation can be performed with a stereotactic headframe in situ. A laryngeal mask is the quickest airway device to insert and can be inserted while the mannequin is in the standard surgical position. Further study is needed to validate the results in patients.

Anesthetic modality and hemodynamic management during mechanical thrombectomy (MT) for acute ischemic stroke (AIS) are potential contributors to the success of revascularization. The aims of our study were to review the hemodynamic management by anesthesiologists and clinical outcomes in patients undergoing MT under conscious sedation.Retrospective cohort study of patients with anterior circulation AIS from January 2012 to March 2016. Primary outcome was hemodynamic intervention, defined as administration of vasoactive drugs to maintain systolic blood pressure (BP) between 140 and 180 mm Hg. The secondary outcome was poor hemodynamic control, defined as BP outside target for15 minutes despite hemodynamic intervention. We performed regression analysis to determine the predictors of hemodynamic intervention and poor hemodynamic control.A total of 126 patients were included in this study; 92% (116) receiving conscious sedation and 8% (10) no sedation. Upon arrival to the neuroradiology suite, systolic BP was140 mm Hg in 30.2% of the patients and180 mm Hg in 14.3%. Hemodynamic intervention was required in 38.9% of patients; 15.1% for hypotension and 19.8% for hypertension. In the multivariate analysis, systolic BP on hospital admission (odds ratio, 1.02; 95% confidence interval, 1.00-1.04; P=0.019) constituted a predictor for hemodynamic intervention. Poor hemodynamic control occurred in 12.7% of patients, with lower baseline systolic BP being associated with higher risk of intraprocedural hypotension (odds ratio, 0.92; 95% confidence interval, 0.89-0.96; P0.001). In-hospital mortality was 13.6%.Hemodynamic intervention is frequent during MT under conscious sedation. The routine presence of anesthesiologists during MT may be helpful in maintaining hemodynamic stability and allow rapid treatment of emergent complications. An individualized approach with tailored hemodynamic targets is required during management of patients undergoing MT for AIS.

Introduction Controlling the arterial carbon dioxide tension (PaCO2) to reduce the cerebral blood flow (CBF) and the intracranial pressure is a common practice in neuroanesthesia. A change in CBF in response to change in PaCO2 is termed as cerebrovascular reactivity to carbon dioxide (CVR-CO2). Studies have shown that, both inhalational and intravenous anesthetic agents have variable effects on CVR-CO2 and the effect of anesthetic agents on CVR also varies with many physiological and pathologic conditions. The objectives of this review were to evaluate the effect of anesthetic agents on the CVR-CO2 in adults and to determine how this response is modified by other physiological and pathologic factors. Methods We conducted a systematic search of the databases of Medline, Embase, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews using related term components for both CVR-CO2 and anesthesia. Our primary outcome of this review was to determine whether the CVR-CO2 is maintained under anesthesia. The other endpoints of this review are to determine the effect of other factors (age, sex, medical comorbidities, and cerebrovascular pathology) on the CVR-CO2 under anesthesia. Because of the methodological heterogeneity in the primary studies, quantitative analysis of the data was not possible, and therefore, we have summarized the data qualitatively. Results Our search strategy yielded 1356 citations. After excluding nonpertinent papers, 38 studies were included for the systematic review. Nineteen randomized controlled trials and 19 observational studies met inclusion criteria and a total of 793 patients were studied. Transcranial Doppler was the most commonly used method for measuring CBF and changing the respiratory rate and/or minute ventilation were the most commonly used method to change the CO2 tension. CVR-CO2 is maintained with both inhalational and intravenous anesthetic agents within the range of concentrations used in clinical anesthesia. At doses leading to a broadly equivalent depth of anesthesia, the reactivity value was highest with isoflurane and the least with propofol. Individual agents differ in their degree of reactivity to hypercapnic and hypocapnic stimuli. CVR-CO2 is impaired in elderly patients when compared with young patients with both sevoflurane and propofol anesthesia. In patients with medical comorbidities, the CVR-CO2 impairment under anesthesia was associated with the severity of the underlying diseases and not the anesthetic agents. Conclusions Our systematic review showed that within the clinical anesthesia concentrations, CVR-CO2 is maintained under both propofol and inhalational agents. However, most of the information available is from non-neurosurgical patients and these studies also suffer from significant methodological heterogeneity. Therefore, we were limited by the amount and the quality of data available for this review.

During spinal surgery, intraoperative monitoring of motor-evoked potentials (MEPs) is a useful means of assessing the intraoperative integrity of corticospinal pathways. However, MEPs are known to be particularly sensitive to the suppressive effects of inhalational halogenated anesthetic agents.To investigate the effects of increasing end-tidal concentrations of desflurane and sevoflurane anesthesia in a background of propofol and remifentanil with multipulse cortical stimulation on intraoperative monitoring of MEPs.In this randomized crossover trial, 14 consecutive patients (7 in each arm) undergoing major spine surgery, under a background anesthetic of propofol (75 to 125 mcg/kg/min) and remifentanil (0.1 to 0.2 mcg/kg/min), were randomly assigned to receive the sequence of inhalational agents studied: either DES-SEVO (desflurane followed by sevoflurane); or SEVO-DES (sevoflurane followed by desflurane). Multiples (0.3, 0.5, and 0.7) of minimum alveolar concentration (MAC) of desflurane and sevoflurane were administered. After a washout period of 15 minutes using high fresh oxygen/air flows, each of the patients then received the other gas as the second agent. Cortical stimulation was achieved with a train of 5 equivalent square pulses, each 0.05 ms in duration, delivered at 2 ms intervals. MEP recordings were made in the upper limb (UL) from first dorsal interosseus and lower limb (LL) from tibialis anterior with subdermal needle electrodes.At 0.3 MAC desflurane, there was no statistical significant difference in transcranial-evoked MEP amplitudes from the baseline in both UL and LL stimulation. However, this was not the case for sevoflurane for which even a low concentration at 0.3 MAC significantly depressed MEP amplitudes of LL (but not UL) from baseline value. Desflurane at 0.5 and 0.7 MAC depresses LL MEP to 58.4% and 59.9% of baseline, respectively (P0.05), whereas sevoflurane at 0.3, 0.5, and 0.7 MAC depresses LL MEP to 66.2%, 41.3%, and 25.3% of baseline, respectively (P0.05). There was no difference in latency of the responses at any MAC.Inhalational anesthetic agents (sevofluranedesflurane) suppress MEP amplitudes in a dose-dependent manner. The use of 0.3 MAC of desflurane (but not sevoflurane) provided good MEP recordings acceptable for clinical interpretation for both upper and LLs. The LL appears to be more sensitive to anesthetic-induced depression compared with the UL. All patients studied had normal neurological examination hence, these results may not be applicable to those with preexisting deficits.

Background: Ambulatory day surgery is an evolving specialty in line with demands of modern medicine, health care services, and economics, but its role in neurovascular surgery remains controversial. The purpose of this study was to describe our experience of patients undergoing elective clipping of intact cerebral aneurysms as day surgery. Methods: This retrospective and prospective observational study was carried out as a cohort review of patients who underwent outpatient clipping of an intact intracranial aneurysm at the Toronto Western Hospital, University Health Network, between May 2009 and November 2012. Patients were categorized as success (discharged on the same day) or failure (requiring unplanned postoperative hospital admission) of day surgery. Data included the preoperative assessment of the patient, anesthetic management, postoperative care, and the incidence of perioperative complications. Outcomes were duration of hospital stay, and any problems preventing same-day discharge. Results: During the study period 25 patients aged 54±9 years underwent outpatient aneurysm repair. Seventeen patients (68%) successfully completed day surgery, and 8 patients (32%) were admitted to the hospital after surgery due to perioperative complications. Duration of hospital stay in the failure group ranged from 2 to 18 days. Conclusions: Our data demonstrates that surgical clipping of unruptured cerebral aneurysms may be performed in an outpatient setting. Careful selection of day surgery candidates and postoperative assessment for complications is needed. Further research is needed to identify potential risk factors and to target patient subgroups for successful ambulatory surgery.

Anxiety is common in surgical patients, with an incidence of 60% to 92%. There is little information on the incidence and severity of preoperative anxiety in patients scheduled for neurosurgery. The aim of this study was to measure the level of preoperative anxiety in neurosurgical patients and to assess any influencing factors. After the Institutional Review Board approval and informed written consent, 100 patients booked for neurosurgery were interviewed preoperatively. Each patient was asked to grade their preoperative anxiety level on a verbal analog scale, Amsterdam Preoperative Anxiety and Information Scale, and a set of specific anxiety-related questions. The anxiety scores and the responses to the questions were compared between the sex, age, weight, diagnosis, and history of previous surgery. The mean age (+/-SD) was 50+/-13 years. The preoperative diagnosis was tumor (n=64), aneurysm (n=14), and other (n=22). Overall verbal analog scale was 5.2+/-2.7; the score was higher for female (5.8+/-2.8) than male patients (4.6+/-2.5) (P

The use of functional stereotactic neurosurgery is increasing for treatment of patients with movement disorders and other chronic illnesses. The anesthetic considerations include the influence of the anesthetic agents on the microelectrode recordings and stimulation testing of an awake patient. The purpose of this study was to review the anesthetic management and incidences of intraoperative complications during functional neurosurgery in our institution. One hundred seventy-eight patients underwent an ablative procedure (n = 6) or the insertion of deep brain stimulator (n = 172) under monitored anesthesia care for movement disorders (n = 124), chronic pain (n = 20), and other procedures (n = 34). Local anesthetic was used for head frame pin sites and burr holes. No sedation/analgesia was administered to 57 (32%) patients. One patient required conscious sedation and another general anesthesia for the entire procedure. The remainder received small increments (mean +/- SD) of propofol (113 +/- 73 mg), midazolam (1.6 +/- 0.8 mg), and/or fentanyl (93 +/- 55 mug). Intraoperative complications that occurred in 16% of the patients included seizures (n = 8), change in neurologic status (n = 5), airway obstruction (n = 2), and hypertension (n = 7). Functional neurosurgery can be performed with minimal anesthesia in many patients. Awareness and vigilance can improve the identification and early treatment of intraoperative complications such as seizures, loss of airway, and changes in the neurologic status.

Summary Somatosensory evoked potentials (SSEP) have been used during cerebral aneurysm surgery to monitor the integrity of neural pathways. The purpose of this study was to evaluate the effectiveness of SSEP monitoring as a predictor of neurological outcome during temporary arterial occlusion. In a series of 157 patients monitored, 97 patients had temporary occlusion of the feeding artery. Twenty-three patients developed a SSEP change during temporary occlusion, 15 reversible (recovery of the change after the release of occlusion), and 8 persistent (no recovery) changes. A persistent change predicted a postoperative neurological deficit in each case, whereas, of the 15 patients with reversible changes, only 5 had postoperative deficits. Seventyfour patients had no change on SSEP monitoring but 10 patients did have new neurological deficits postoperatively. The false positive rate was 43% and the false negative rate was 14%. SSEP was a better predictor of neurological deficits in patients with aneurysms of the carotid circulation than of the vertebral-basilar arteries. Despite these limitations, we find SSEP monitoring useful during temporary occlusion in cerebral aneurysm surgery.

The perioperative management of the airway in patients with cervical spine disease requires careful consideration. In an observational prospective cohort study, we assessed the preoperative factors that may have influenced the anesthesiologists' choice for the technique of intubation and the incidence of postoperative airway complications. We recorded information from 327 patients: mean (+/-SD) age 51+/-15 year, 138 females and 189 males, for anterior surgical approach (n=195) and posterior (n=132). The technique of intubation used was awake fiberoptic bronchoscopy (FOB) in 39% (n=128), asleep FOB 32% (n=103), asleep laryngoscopy 22% (n=72), and other asleep 7% (n=24). Awake FOB was predominately chosen for intubating patients with myelopathy (45%), unstable/fractured spine (73%), and spinal stenosis (55%) but patients with radiculopathy had more asleep FOB (49%) (P