Lumbar Intradural Neurenteric Cyst: A Rare Pathology in an Unusual Location.

A previously healthy 48-year-old female presented to the emergency department with a 2-week history of low back pain, progressive lower extremities weakness, and right leg numbness. There were no bowel or bladder dysfunction symptoms. Spine magnetic resonance imaging (MRI) showed an intradural cystic lesion dorsal to the spinal cord at the level of L1 measuring 1.6 × 2.1 × 4.1 cm, which was T1 hypointense and T2 hyperintense, with a small soft tissue component and no gadolinium enhancement (Figure 1). A small lipomatous component was also noted. There were no associated vertebral anomalies. The patient underwent a T12-L2 laminectomy and cyst resection, which was subtotal due to the cyst adherence to the conus medullaris. Histopathology showed characteristic features of a neurenteric cyst, with respiratory-type epithelium in the cyst wall (Figure 2). Eight months later, follow-up MRI showed no evidence of recurrence. The patient reported improved sensation in the lower extremities; however, there was some residual weakness predominantly in the proximal hip flexors bilaterally.

Impaired peri-nidal cerebrovascular reserve in seizure patients with brain arteriovenous malformations.

Epileptic seizures are a common presentation in patients with newly diagnosed brain arteriovenous malformations, but the pathophysiological mechanisms causing the seizures remain poorly understood. We used magnetic resonance imaging-based quantitative cerebrovascular reactivity mapping and conventional angiography to determine whether seizure-prone patients with brain arteriovenous malformations exhibit impaired cerebrovascular reserve or morphological angiographic features predictive of seizures. Twenty consecutive patients with untreated brain arteriovenous malformations were recruited (10 with and 10 without epileptic seizures) along with 12 age-matched healthy controls. Blood oxygen level-dependent MRI was performed while applying iso-oxic step changes in end-tidal partial pressure of CO(2) to obtain quantitative cerebrovascular reactivity measurements. The brain arteriovenous malformation morphology was evaluated by angiography, to determine to what extent limitations of arterial blood supply or the presence of restricted venous outflow and tissue congestion correlated with seizure susceptibility. Only patients with seizures exhibited impaired peri-nidal cerebrovascular reactivity by magnetic resonance imaging (0.11 ± 0.10 versus 0.25 ± 0.07, respectively; P < 0.001) and venous drainage patterns suggestive of tissue congestion on angiography. However, cerebrovascular reactivity changes were not of a magnitude suggestive of arterial steal, and were probably compatible with venous congestion in aetiology. Our findings demonstrate a strong association between impaired peri-nidal cerebrovascular reserve and epileptic seizure presentation in patients with brain arteriovenous malformation. The impaired cerebrovascular reserve may be associated with venous congestion. Quantitative measurements of cerebrovascular reactivity using blood oxygen level-dependent MRI appear to correlate with seizure susceptibility in patients with brain arteriovenous malformation.

Long-term visual outcome and aneurysm obliteration rate for very large and giant ophthalmic segment aneurysms: assessment of surgical treatment.

BACKGROUND: Standard endovascular therapy has shown little success in treatment of very large and giant ophthalmic segment aneurysms. We hypothesize that surgical treatment of these aneurysms yields better results in terms of visual function and aneurysm obliteration. METHODS: The Toronto Brain Vascular Malformation Study Group database was analyzed to retrieve patients treated surgically for very large (>15 mm) and giant aneurysms of the ophthalmic segment of the carotid artery. Preoperative data and postoperative long-term outcomes with specific consideration for visual function and aneurysm obliteration were evaluated. RESULTS: Of the 257 patients with ophthalmic and paraophthalmic aneurysms, 38 patients had very large or giant aneurysms. Twenty-one underwent surgical treatment; 19 had direct clipping; 1 had trapping, and 1 underwent trapping and bypass. Fifteen patients had unruptured and six had ruptured aneurysms. The mean follow-up period was 88 months. Six (28%) aneurysms had a small residual neck remnant. Of the 12 patients with documented preoperative visual deficit, 9 (75%) improved, 2 (16%) remained stable, and 1 (8%) worsened. Two patients had mild to moderate new visual deficit. Thus, the surgery-related visual complications were 14%. Eighteen patients (86%) had a good or excellent outcome (GOS IV and V). Presentation with prior visual deficit and poor neurological function were predictors of worse visual and clinical outcome, respectively (P = 0.02 and 0.01). CONCLUSIONS: There is considerable surgery-related risk for optic pathways during treatment of very large and giant ophthalmic segment aneurysms. Surgery, however, seems to be the treatment of choice in terms of overall visual outcome and aneurysm obliteration as compared to the current endovascular results in this subset of patients.

Extraventricular anaplastic ependymoma with metastasis to scalp and neck.

We report a case of anaplastic ependymoma with extracranial metastases in a 22-year-old female. The patient originally presented with headaches and dysarthria. Neuroimaging revealed a large solid and cystic right fronto-temporal lesion. It was located completely extraventricularly and a glioblastoma was suspected based on the neuroimaging findings. A gross total resection was achieved. Histopathologic examination revealed an anaplastic ependymoma. The patient was treated with radiotherapy. Approximately 1 year after the initial surgery, the patient presented with metastatic disease to the scalp. At 2 years, an intraparotid metastasis was detected. Subsequent neck dissection revealed positive lymph nodes at several levels. It was followed by radiotherapy to the neck. 5 years after the initial surgery, the patient has residual metastatic disease. The case is discussed and the literature on extraventricular ependymal neoplasms is reviewed.

Proximity to the treating centre and outcomes following subarachnoid hemorrhage.

BACKGROUND: In the management of subarachnoid hemorrhage (SAH), the potential for early complications and the centralization of limited resources often challenge the delivery of timely neurosurgical care. We sought to determine the impact of proximity to the accepting neurosurgical centre on outcomes following aneurysmal SAH. METHODS: Using administrative data, we analyzed patients undergoing treatment for aneurysmal subarachnoid hemorrhage at neurosurgical centres in Ontario between 1995 and 2004. We compared mortality for patients receiving treatment at a centre in their county (in-county) versus those treated from outside counties (out-of-county). We also examined the impact of distance from the patient's residence to the treating centre. RESULTS: The mortality rates were significantly lower for in-county versus out-of-county patients (23.5% vs. 27.6%, p=0.009). This advantage remained significant after adjusting for potential confounders (HR=0.84, p=0.01). The relationship between distance from the treating centre and mortality was biphasic. Under 300 km, mortality increased with increasing distance. Over 300 km, a survival benefit was observed. CONCLUSIONS: Proximity to the treating neurosurgical centre impacts survival after aneurysmal SAH. These results have significant implications for the triage of these critically ill patients.

Surgical activity of first-year Canadian neurosurgical residents.

INTRODUCTION: Surgical activity is probably the most important component of surgical training. During the first year of surgical residency, there is an early opportunity for the development of surgical skills, before disparities between the skill sets of residents increase in future years. It is likely that surgical skill is related to operative volumes. There are no published guidelines that quantify the number of surgical cases required to achieve surgical competency. The aim of this study was to describe the current trends in surgical activity in a recent cohort of first-year Canadian neurosurgical trainees. METHODS: This study utilized retrospective database review and survey methodology to describe the current state of surgical training for first-year neurosurgical trainees. A committee of five residents designed this survey in an effort to capture factors that may influence the operative activity of trainees. RESULTS: Nine out of a cohort of 20 first-year Canadian neurosurgical trainees that began training in July of 2008 participated in the study. The median number of cases completed by a resident during the initial three month neurosurgical rotation was 66, within which the trainee was identified as the primary surgeon in 12 cases. Intracranial hemorrhage and cerebrospinal fluid diversion procedures were the most common operations to have the trainee as primary surgeon. CONCLUSION: Based on this pilot study, it appears that the operative activity of Canadian first-year residents is at least equivalent to the residents of other studied training systems with respect to volume and diversity of surgical activity.

The natural history and predictive features of hemorrhage from brain arteriovenous malformations.

BACKGROUND AND PURPOSE: Patients harboring brain arteriovenous malformations (bAVMs) are at a lifelong risk for hemorrhagic strokes, but the natural history is poorly understood. We examined the impact of demographic and angiographic features on the likelihood of future hemorrhage. METHODS: A prospectively accrued database of bAVM patients maintained at the Toronto Western Hospital was analyzed; 678 consecutive, prospectively enrolled bAVM patients were followed for 1931.7 patient-years. The rate of hemorrhage over long-term follow-up was recorded. The impact of baseline clinical and radiographic features and partial treatment on time to hemorrhage were analyzed using survival analysis. Neurological outcome after hemorrhage was assessed using the Glasgow Outcome Score. RESULTS: Hemorrhage rates were 4.61% per year for the entire cohort (n=678), 7.48% per year for bAVMs with initial hemorrhagic presentation (n=258), 4.16% per year for initial seizure presentation (n=260), 3.99% per year for patients not harboring aneurysms (n=556), 6.93% per year for patients with associated aneurysms (n=122), and 5.42% per year for bAVMs with deep venous drainage (n=365). Hemorrhagic presentation was a significant independent predictor of future hemorrhage (HR, 2.15; P<0.01), whereas associated aneurysms (HR, 1.59; P=0.07) and deep venous drainage (HR, 1.59; P=0.07) showed a trend toward significance. Hemorrhage risk was unchanged in patients who underwent partial arteriovenous malformation embolization (n=211; HR, 0.875; P=0.32). CONCLUSIONS: Brain arteriovenous malformations presenting with hemorrhage, with deep venous drainage, or associated aneurysms have approximately 2-fold greater likelihood of a future hemorrhage. Partial treatment by embolization does not alter these risks. This natural history should be taken into account in the treatment strategy.

Intraoperative biplanar rotational angiography during neurovascular surgery. Technical note.

OBJECT: The purpose of this study was to evaluate the authors' initial experience with the integration of high-resolution rotational and biplanar angiography during neurovascular operative procedures. METHODS: Eight patients with intracerebral arteriovenous malformations (AVMs) and aneurysms underwent surgical treatment of their lesions in a combined endovascular surgical suite. After initial head positioning, preoperative biplane and rotational angiography was performed. Resection of the AVM or clipping of the aneurysm was then performed. Further biplane and rotational 3D angiograms were obtained intraoperatively to confirm satisfactory treatment. RESULTS: One small residual AVM identified intraoperatively necessitated further resection. One aneurysm was clipped during endovascular inflation of an intracarotid balloon for temporary proximal control. The completeness of treatment was confirmed on intraoperative 3D rotational angiography in all cases, and there were no procedure-related complications. CONCLUSIONS: Intraoperative rotational angiography performed in an integrated biplane angiography/surgery suite is a safe and useful adjunct to surgery and may enable combining endovascular and surgical procedures for the treatment of complex vascular lesions.

Assessment of extracranial-intracranial bypass patency with 64-slice multidetector computerized tomography angiography.

INTRODUCTION: Extracranial-intracranial (EC/IC) bypass is a useful procedure for the treatment of cerebral vascular insufficiency or complex aneurysms. We explored the role of multidetector computed tomography angiography (MDCTA), instead of digital subtraction angiography (DSA), for the postoperative assessment of EC/IC bypass patency. METHODS: We retrospectively analyzed a consecutive series of 21 MDCTAs from 17 patients that underwent 25 direct or indirect EC/IC bypass procedures between April 2003 and November 2007. Conventional DSA was available for comparison in 13 cases. MDCTA used a 64-slice MDCT scanner (Aquilion 64, Toshiba). The proximal and distal patencies were analyzed independently on MDCTA and DSA by a neuroradiologist and a neurosurgeon. The bypass was considered patent when the entire donor vessel was opacified without discontinuity from proximal to distal ends and was visibly in contact with the recipient vessel. RESULTS: MDCTA depicted the patency status in every patient. Bypasses were patent in 22 cases, stenosed in one, and occluded in two. DSA always confirmed the results of the MDCTA (sensitivity = 100%, 95% CI = 0.655-1.0; specificity 100%, 95% CI = 0.05-1.0). CONCLUSIONS: MDCTA is a non-invasive and accurate exam to assess the postoperative EC/IC bypass patency and is a promising technique in routine follow-up.

Overview of the current role of endovascular and surgical treatment in spinal dural arteriovenous fistulas.

Dural arteriovenous fistulas are the most common vascular malformations of the spinal cord. These benign vascular lesions are considered straightforward targets of surgical treatment and possibly endovascular embolization, but the outcome in these cases depends mainly on the extent of clinical dysfunction at the time of the diagnosis. A timely diagnosis is an equally important factor, with early treatment regardless of the type more likely to yield significant improvements in neurological functioning. The outcomes after surgical and endovascular treatment are similar if complete obliteration of the fistulous site is obtained. In the present study, the authors evaluated the current role of each modality in the management of these interesting lesions.

Ischemia and status epilepitcus result in enhanced phosphorylation of calcium and calmodulin-stimulated protein kinase II on threonine 253.

Ca2+-stimulated protein kinase II (CaMKII) is critically involved in the regulation of synaptic function and is implicated in the neuropathology associated with ischemia and status epilepticus (SE). The activity and localization of CaMKII is regulated by multi-site phosphorylation. In the present study we investigated the effects of global ischemia followed by reperfusion and of SE on the phosphorylation of CaMKII on T253 in rat forebrains and compared this to the phosphorylation of T286. Both ischemia and SE resulted in marked increases in the phosphorylation of T253, and this was particularly marked in the postsynaptic density (PSD). Phosphorylation of T286 decreased rapidly towards basal levels following ischemia whereas phosphorylation of T253 remained elevated for between 1 and 6 h before decreasing to control values. Following SE, phosphorylation of T253 remained elevated for between 1 and 3 h before decreasing to control levels. In contrast, phosphorylation of T286 remained elevated for at least 24 h following the termination of SE. Total CaMKII associated with PSDs transiently increased 10 min following ischemia, but only several hours following SE. The results demonstrate that phoshorylation of CaMKII on T253 is enhanced following both ischemia/reperfusion and SE and indicate that the phosphorylation of T253 and T286 are differentially regulated.

Thrombophilic factors and the formation of dural arteriovenous fistulas.

OBJECT: Dural arteriovenous fistulas (DAVFs) are distinct neurovascular entities. Although their exact origins are unknown, venous thrombosis and venous hypertension are likely to be major inducing factors. To address the relationship between DAVFs and thrombophilic factors, the authors conducted a case-control study at a single institution and performed a metaanalysis of the literature. METHODS: Forty patients with DAVFs at Toronto Western Hospital were recruited to complete a questionnaire and to donate blood samples for factor V Leiden mutation and factor II G20210A mutation screening and assessment of coagulation factors. The questionnaire was designed to collect information on each participant's specific history of venous thrombosis, medications, and race. A control group of 33 healthy volunteers agreed to the same protocol. A MEDLINE search of the literature from 1966 to the present was conducted and three relevant series were found. The results of the present study were pooled with the data from the literature. RESULTS: Combining institutional results with the results from the literature yielded a total of 121 patients and 178 control group members. Thrombophilic mutations were present in 16 patients and four healthy volunteers, with an odds ratio (OR) of 4.69 for factor V Leiden (95% confidence interval [CI] 1.24-17.69) and an OR of 10.87 for the prothrombin G20210A allele (95% CI 1.32-89.51). Levels of the basic coagulation profile, fibrinogen, and factor VIII were within normal limits. CONCLUSIONS: Patients with the factor V Leiden and factor II G20210A mutations are at a higher risk for DAVFs. However, because these mutations are not implicated in the vast majority of DAVFs, routine screening is not recommended.

A discriminative prediction model of neurological outcome for patients undergoing surgery of brain arteriovenous malformations.

BACKGROUND AND PURPOSE: To develop and validate a discriminative model for predicting neurological morbidity after brain arteriovenous malformation (bAVM) surgery. METHODS: Of 233 consecutive, prospectively enrolled patients undergoing bAVM surgery, the first 175 were used to derive, and the last 58 to validate, the prediction model. Demographic and angiographic factors were related to modified Rankin Scale scores assigned before, within 72 hours, at 7 days and at > or =1 year after surgery to seek predictors of postoperative neurological deficits (modified Rankin Scale score > or =3). These factors included nidus size, eloquence, venous drainage, diffuseness, white matter configuration, arterial perforator supply and associated aneurysms. RESULTS: Brain eloquence, diffuse nidus and deep venous drainage were significant predictors of early disabling neurological deficits (odds ratios of 4.33, 3.49 and 2.38, respectively). The rounded odds ratios form a weighted 9-point prediction model (maximum scores for eloquence+diffuseness+deep drainage=4+3+2). The score discriminated the probability of experiencing both early (first week) and permanently (at > or =1 year) disabling neurological deficits as follows: 0 to 2: 1.8%, 3 to 5: 17.4%, 6 to 7: 31.6%, >7: 52.9% for early and 0 to 2: 1.8%, 3 to 5: 4.4%, 6 to 7: 18.4%, >7: 32.4% for permanently disabling outcomes. The discrimination of the model was 0.80 with 2.8% optimism. Validation in the second patient cohort revealed good performance at risk stratification. CONCLUSIONS: Relative weights assigned to brain eloquence, diffuse nidus morphology and deep venous drainage of a bAVM provide a simple and discriminative prediction model for neurological outcome after bAVM surgery.

Safety of intracranial aneurysm surgery performed in a postgraduate training program: implications for training.

OBJECT: Patient care and educational experience have long formed a dichotomy in modem surgical training. In neurosurgery, achieving a delicate balance between these two factors has been challenged by recent trends in the field including increased subspecialization, emerging technologies, and decreased resident work hours. In this study the authors evaluated the experience profiles of neurosurgical trainees at a large Canadian academic center and the safety of their practice on patient care. METHODS: Two hundred ninety-three patients who underwent surgery for intracranial aneurysm clipping between 1993 and 1996 were selected. Prospective data were available in 167 cases, allowing the operating surgeon to be identified. Postoperative data and follow-up data were gathered retrospectively to measure patient outcomes. In 167 cases, a total of 183 aneurysms were clipped, the majority (91%) by neurosurgical trainees. Trainees performed dissections on aneurysms that were predominantly small (< 1.5 cm in diameter; 77% of patients) and ruptured (64% of patients). Overall mortality rates for the patients treated by the trainee group were 4% (two of 52 patients) and 9% (nine of 100 patients) for unruptured and ruptured aneurysm cases, respectively. Patient outcomes were comparable to those reported in historical data. Staff members appeared to be primary surgeons in a select subset of cases. CONCLUSIONS: Neurosurgical trainees at this institution are exposed to a broad spectrum of intracranial aneurysms, although some case selection does occur. With careful supervision, intracranial aneurysm surgery can be safely delegated to trainees without compromising patient outcomes. Current trends in practice patterns in neurosurgery mandate ongoing monitoring of residents' operative experience while ensuring continued excellence in patient care.

Microstent-assisted coiling for wide-necked intracranial aneurysms.

OBJECTIVE: To describe the results, technical feasibility, efficacy and challenges encountered in our preliminary experience using a self-expandable microstent, optimized for intracranial use, as an adjunct in the endovascular treatment of wide-necked aneurysms. METHODS: Only broad-necked aneurysms (dome-to-neck ratio < or = 2, or an isolated neck size > 4.5 mm) were treated with Neuroform microstent from July 2003 to May 2004. The techniques used for stent deployment were either parallel or sequential. Angiographic results were recorded immediately for all patients and classified as Class 1 (complete occlusion), Class 2 (neck remnant) or Class 3 (sac remnant) by three interventional neuroradiologists not involved in the procedure. Follow-up angiography at six months was obtained for one case. Modified Rankin Score scale was assessed for all patients. RESULTS: Seventeen intracranial aneurysms in a total of 18 patients were treated (mean age, 52.2 yr). Eight patients (44.4%) presented with acute subarachnoid hemorrhage. Eleven aneurysms (61.1%) were in the posterior circulation. Average dome size was 10.2 mm (range, 3.7-19.8 mm) and average neck size was 5.36 mm (range, 3.0-10.0 mm). Six out of seven aneurysms of the anterior circulation were approached with parallel technique. Eight aneurysms of the posterior circulation were approached with sequential technique. Average number of coils deployed was 9.64 (range, 4-23 coils). Eleven aneurysms (64.8%) resulted in Class 1 and/or Class 2. One technical failure was observed. Technical complications were recognized in four patients (23.5%), all of them with unruptured aneurysms in the anterior circulation. Two patients (11.7%) presented transient immediate clinical complications. One patient (5.8%) had minor permanent neurological complication. Neither major clinical complications nor death were encountered. Favorable clinical outcome (Modified Rankin Scale score 0-2) was observed in 88.2% of the patients (average follow-up time, 4.72 months). CONCLUSIONS: Absence of major permanent complications and satisfactory immediate obliteration degree in our preliminary experience indicates that microstent-assisted coiling technique is useful for the minimally invasive treatment of broad-necked complex aneurysms that are not ideal for conventional endovascular treatment and are at a high risk for conventional surgical treatment.

Clinical course of cranial dural arteriovenous fistulas with long-term persistent cortical venous reflux.

BACKGROUND AND PURPOSE: The natural history of aggressive (Borden 2 and 3) cranial dural arteriovenous fistulas (DAVFs) is not well described. Reported annual mortality and hemorrhage rates vary widely and range up to 20% per year. A consecutive single-center cohort of 236 cases that presented with a cranial DAVF between June 1984 and May 2001 was reviewed for the consequences of long-term persistent cortical venous reflux (CVR). METHODS: A group of 118 cranial DAVFs was selected for the presence of CVR. All patients were offered treatment aimed at the disconnection of the CVR. Patients who declined or had partial treatment with persistence of the CVR had long-term clinical and angiographic follow-up to study the disease course of this select group. RESULTS: Treatment was instituted in 101 of the 118 patients (85.6%). Three patients were lost to follow-up. The remaining 14 nontreated patients (11.9%) and the partially treated patients (n=6) were assessed clinically and angiographically over time. The mean follow-up in this select group was 4.3 years (86.9 patient-years). During follow-up, 7 patients suffered an intracranial hemorrhage (35%). The incidence of nonhemorrhagic neurological deficit was 30%. Nine patients (45%) died: 6 patients expired after a hemorrhage, and 3 patients died of progressive neurological deterioration. Two patients demonstrated a spontaneous closure of the DAVF (10%). CONCLUSIONS: Persistence of the CVR in cranial DAVFs yields an annual mortality rate of 10.4%. Excluding events at presentation, in this series the annual risk for hemorrhage or nonhemorrhagic neurological deficit during follow-up was 8.1% and 6.9%, respectively, resulting in an annual event rate of 15.0%.

Large and deep brain arteriovenous malformations are associated with risk of future hemorrhage.

BACKGROUND AND PURPOSE: The correlation between features present in brain arteriovenous malformations (AVMs) such as size, location, and angioarchitecture at presentation with subsequent risk of hemorrhage may be valuable in predicting the behavior of AVMs and therefore guiding management. METHODS: We prospectively followed up 390 patients with brain AVMs at the University of Toronto Vascular Malformation Study Group. Location, size, angioarchitecture details, blood supply, and clinical presentation were recorded at baseline. Intracranial hemorrhages during follow-up were recorded. Significant factors from univariate analyses were used to construct a multivariate model relating the above features to the occurrence of hemorrhage. RESULTS: Thirty-eight patients had bleeding caused by the AVM in a follow-up of 1205 patient-years (mean, 3.1 years per patient). In analyses adjusted for multiple AVM characteristics, large AVMs bled more frequently than small lesions (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.41 to 4.35; P<0.0001), and deep-seated AVMs had more bleeding in follow-up than those located at superficial sites (OR, 5.56; 95% CI, 2.63 to 12.5; P<0.0001). CONCLUSIONS: Deep-seated and large AVMs were significantly more prone to hemorrhage during prospective follow-up. The distinction between factors associated with hemorrhagic presentation and the natural history risk of hemorrhage will be emphasized.