A Canadian National Survey of the Neurosurgical Management of Intracranial Abscesses.

OBJECTIVE: Intracerebral abscess is a life-threatening condition for which there are no current, widely accepted neurosurgical management guidelines. The purpose of this study was to investigate Canadian practice patterns for the medical and surgical management of primary, recurrent, and multiple intracerebral abscesses. METHODS: A self-administered, cross-sectional, electronic survey was distributed to active staff and resident members of the Canadian Neurosurgical Society and Canadian Neurosurgery Research Collaborative. Responses between subgroups were analyzed using the Chi-square test. RESULTS: In total, 101 respondents (57.7%) completed the survey. The majority (60.0%) were staff neurosurgeons working in an academic, adult care setting (80%). We identified a consensus that abscesses >2.5 cm in diameter should be considered for surgical intervention. The majority of respondents were in favor of excising an intracerebral abscess over performing aspiration if located superficially in non-eloquent cortex (60.4%), located in the posterior fossa (65.4%), or causing mass effect leading to herniation (75.3%). The majority of respondents were in favor of reoperation for recurrent abscesses if measuring greater than 2.5 cm, associated with progressive neurological deterioration, the index operation was an aspiration and did not include resection of the abscess capsule, and if the recurrence occurred despite prior surgery combined with maximal antibiotic therapy. There was no consensus on the use of topical intraoperative antibiotics. CONCLUSION: This survey demonstrated heterogeneity in the medical and surgical management of primary, recurrent, and multiple brain abscesses among Canadian neurosurgery attending staff and residents.

Multiple recurrences of spindle cell oncocytoma: A case report and literature review.

Spindle cell oncocytoma (SCO) is a rare tumor originating from pituicytes of the neurohypophysis. It typically occurs in the adult population between 50 and 60 years of age and is often misdiagnosed preoperatively as pituitary adenoma because of similar clinical presentation and neuroimaging features. Diffuse nuclear immunoreactivity for TTF-1 (also known as NK2 homeobox 1 factor) is characteristic of SCO and other tumors of the posterior pituitary. We report a case of SCO in a patient who underwent multiple surgical resections for recurrence. The aim of this case report and literature review is to provide an overview of what is currently known about SCO as well as raise the awareness of this entity to endocrinologists, neurologists, neurosurgeons, and neuropathologists. Our case is also unusual in that the tumor displayed immunoreactivity for neuronal markers, which is a very rare occurrence.

Gaze Behaviors of Neurosurgeon in Performing Gross Movements under Microscope.

BACKGROUND: Frequent intermittent bleeding control and suction are often necessary during microneurosurgical procedures. We compared the visual searching strategy that guides these types of gross hand movements between expert surgeons and neurosurgical residents. METHODS: A total of 70 trials of a microsurgical task consisting of moving a cotton ball with bipolar forceps and a suction instrument under the microscope were recorded. Based on surgical videos, we extracted total task time, boarding time, gaze-tool time gap, number of fixations during the boarding time, and target-locked fixation duration. A comparison of these measures between experts and resident surgeons were performed. RESULTS: No significant difference was found for total task time, boarding time, and number of fixations during the boarding time between the 2 groups of surgeons. However, we found significant differences in the measure of gaze-tool time gap (P < 0.001, partial η2 = 0.54) and the target-locked fixation (P < 0.001, partial η2 = 0.24). Specifically, expert microsurgeons' eyes move to the target board earlier before their tools in hands move (1.01 ± 0.30 seconds) compared with resident microsurgeons (0.44 ± 0.17 seconds). The target-locked fixation duration was also longer among experts comparing to residents (experts: 1.16 ± 0.82 seconds, residents: 0.40 ± 0.30 seconds). CONCLUSIONS: Task time analysis for this basic microsurgical task is not sufficient to evaluate participants' level of expertise. Gaze behavior analysis helps to reveal hidden differences between experts and residents. This research provides more evidence that supports the use of gaze analysis for assessing surgeons' skills in microsurgery.

Early Metabolic Changes in 1H-MRSI Predictive for Survival in Patients With Newly Diagnosed High-grade Glioma.

BACKGROUND: The purpose of this study was to evaluate the association of specific threshold values for changes in metabolic metrics measured from 1H magnetic resonance spectroscopic imaging (MRSI) to survival of patients with high-grade glioma treated with multimodality therapy. PATIENTS AND METHODS: Forty-four patients with newly diagnosed high-grade glioma were prospectively enrolled. Serial MRI and MRSI scans provided measures of tumor choline, creatine, and N-acetylaspartate (NAA). Cox regression analyses adjusted for patient age, KPS, and delivery of concurrent chemotherapy were used to assess the association of changes in metabolic metrics with survival. RESULTS: Median follow-up time for patients at risk was 13.4 years. Overall survival (OS) was longer in patients with ≤20% increase (vs. >20%) in normalized choline (p=0.024) or choline/NAA (p=0.024) from baseline to week 4 of RT. During this period, progression-free survival (PFS) was longer in patients with ≤40% increase (vs. >40%) in normalized choline (p=0.013). Changes in normalized creatine, choline/creatine, and NAA/creatine from baseline to mid-RT were not associated with OS. From baseline to post-RT, changes in metabolic metrics were not associated with OS or PFS. CONCLUSION: Threshold values for serial changes in choline metrics on mid-RT MRSI associated with OS and PFS were identified. Metabolic metrics at post-RT did not predict for these survival endpoints. These findings suggest a potential clinical role for MRSI to provide an early assessment of treatment response and could enable risk-adapted therapy in clinical trial development and clinical practice.

Neurosurgical performance between experts and trainees: Evidence from drilling task.

BACKGROUND: Lumbar laminectomy is a common neurosurgery that requires precise manipulation of power drills. We examined the fine movement controls of novice neurosurgeons in drilling tasks and compared its accuracy to expert surgeons' performance. METHODS: Four experts and three novice neurosurgeons performed a lumbar laminectomy on a three-dimensional printed spine model. Scene video and surgeons' eye movements were recorded. Independent sample t-Tests were conducted on the number of jump, total fixation durations, pre-jump fixation durations, post-jump fixation durations and jump distances over novice and expert surgeons. RESULTS: No statistically significant differences were recorded in terms of total fixations and pre-jump fixation durations. However, novices had more jumping events, greater jump distances and longer post-jump fixation durations when compared to expert neurosurgeons. CONCLUSION: Differences in movement accuracy and eye measures were found between expert and novice neurosurgeons during a simulated microscopic lumbar laminectomy. A more comprehensive understanding of surgeon's fine movement control mechanism and eye-hand coordination in microsurgery is essential for us before building an enhanced training protocol for surgical residents in neurosurgery.

Eye-Hand Coordination of Neurosurgeons: Evidence of Action-Related Fixation in Microsuturing.

OBJECTIVE: We examined performance differences between expert and novice neurosurgeons under a surgical microscope with the goal to evaluate surgical expertise. METHODS: The Tobii eye-tracker was used to record surgeons' eye movements while they performed a microsuturing task. A total of 19 expert and 18 novice trials were recorded under the microscope. Surgical videos were annotated to label subtasks and critical actions. Total suturing time and subtask times were also compared between novice and expert surgeons. At 3 critical and discrete surgical actions (needle piercing into tissue, exiting, and thread cutting) we examined eye fixation that was directly coupled to each of these actions. RESULTS: Compared with novices, expert surgeons completed the suture with shorter total time (258.52 ± 102.14 seconds vs. 330.02 ± 96.52 seconds, P = 0.038), penetration time (17.15 ± 3.50 seconds vs. 26.26 ± 18.58 seconds, P = 0.043), and knot-tying time (194.63 ± 94.55 seconds vs. 262.52 ± 79.05 seconds, P = 0.025). On average, experts displayed longer fixation (1.62 seconds) and preaction fixation time (1.3 seconds) than novices (fixation time = 1.24 seconds, P = 0.048; preaction fixation = 0.82 seconds, P = 0.005)). Experts maintained their visual engagement constantly over the 3 levels of subtasks while novices required a longer fixation time for the challenging piercing action than for the exiting and cutting action. CONCLUSIONS: The action-related fixation can be used to evaluate microsurgeons' level of expertise and in surgical education for gaze training.

A nationwide prospective multicenter study of external ventricular drainage: accuracy, safety, and related complications.

OBJECTIVE: External ventricular drainage (EVD) catheters are associated with complications such as EVD catheter infection (ECI), intracranial hemorrhage (ICH), and suboptimal placement. The aim of this study was to investigate the rates of EVD catheter complications and their associated risk factor profiles in order to optimize the safety and accuracy of catheter insertion. METHODS: A total of 348 patients with urgently placed EVD catheters were included as a part of a prospective multicenter observational cohort. Strict definitions were applied for each complication category. RESULTS: The rates of misplacement, ECI/ventriculitis, and ICH were 38.6%, 12.2%, and 9.2%, respectively. Catheter misplacement was associated with midline shift (p = 0.002), operator experience (p = 0.031), and intracranial length (p < 0.001). Although mostly asymptomatic, ICH occurred more often in patients receiving prophylactic low-molecular-weight heparin (LMWH) (p = 0.002) and those who required catheter replacement (p = 0.026). Infectious complications (ECI/ventriculitis and suspected ECI) occurred more commonly in patients whose catheters were inserted at the bedside (p = 0.004) and those with smaller incisions (≤ 1 cm) (p < 0.001). ECI/ventriculitis was not associated with preinsertion antibiotic prophylaxis (p = 0.421), catheter replacement (p = 0.118), and catheter tunneling length (p = 0.782). CONCLUSIONS: EVD-associated complications are common. These results suggest that the operating room setting can help reduce the risk of infection, but not the use of preoperative antibiotic prophylaxis. Although EVD-related ICH was associated with LMWH prophylaxis for deep vein thrombosis, there were no significant clinical manifestations in the majority of patients. Catheter misplacement was associated with operator level of training and midline shift. Information from this multicenter prospective cohort can be utilized to increase the safety profile of this common neurosurgical procedure.

Intraventricular atypical teratoid rhabdoid tumour in an adult: a case report and literature review.

We report a case of atypical teratoid/rhabdoid tumour (AT/RT) in an adult patient in the deep grey matter with extension into the lateral ventricle. To our knowledge, this is the first example of AT/RT involving the lateral ventricle in an adult. The patient presented with headache and confusion, and subsequently required emergent surgery. His postoperative course was complicated by hemorrhage into the surgical site. The location and vascularity of the tumour affected the extent of resection achieved and likely contributed to postoperative complications. We discuss radiological features of AT/RT in adults and implications for investigations and management.

Management of ruptured posterior fossa arteriovenous malformations.

OBJECTIVE: Posterior fossa arteriovenous malformations (pAVMs) are rare and because of their location at or close to vital structures, their treatment remains challenging despite overall improvements in the management of cerebrovascular lesions. We reviewed our recent series of ruptured pfAVMs in search of guiding principles in the management of these complex lesions. METHODS: This is a retrospective series of consecutive patients admitted for a ruptured pfAVM from 2002 to 2013. We analyzed clinical and radiological data, as well as initial and definitive management. Outcome was assessed using the modified Rankin Scale (mRS) at 6 months. RESULTS: The study included 34 patients (19 women and 15 men). Upon admission, 79% of patients presented with an intra-cerebellar hematoma, 42% of which required urgent drainage. Hydrocephaly was also present in 82% of patients, 56% of which required emergency ventriculostomy. There was an aneurysm associated with the AVM in 47% of cases. In 38% of the cases, the aneurysm was the source of the hemorrhage. Only 68% of patients were amenable to undergo treatment of the AVM: 24% exclusively by surgery, 9% by embolization, 3% by radiosurgery, and 32% using combined means. Five patients died within the first week: one as a direct result of the severity of the hemorrhage, and the other four due to re-bleeding before treatment. Outcome was favorable (mRS 0-2) in 71% of patients. CONCLUSION: Patients with a ruptured pfAVM are often comatose upon admission, requiring emergency live-saving surgical treatment. An associated aneurysm is often the source of bleeding which if dealt with immediately, offers time to plan the most appropriate strategies to eliminate the AVM. Nevertheless, early re-bleeding is frequent, and a cause of concern as it often leads to death. Despite the gravity of the clinical condition upon admission, outcome is favorable for those amenable to treatment.