Bilateral mirror image lumbar spinal dural arterial venous fistula: a rare case and systematic review of the literature.

BACKGROUND: Spinal dural arteriovenous fistulas (SDAVF) are rare with an incidence of 5-10/million annually. They can be difficult to diagnose causing a delay in treatment with significant morbidity. We describe the first case in the literature of a symptomatic mirror lumbar SDAVF which may go unnoticed due to its unique vascular anatomy. CASE DESCRIPTION: A 78-year-old gentleman presented with a progressive deterioration in his walking distance and urinary retention. An initial MRI scan of the whole spine did not show features suggestive of an underlying vascular malformation. During further investigations of neurological causes, the patient continued to have progressive symptoms over a 10-month period resulting in a repeat MRI scan. This showed a new finding of cord oedema without abnormal flow voids. He went on to have vascular imaging which demonstrated a mirror L3 SDAVF and underwent subsequent surgical management. At follow up there was a significant improvement in symptoms. CONCLUSIONS: Completing a systematic review of the literature we find that the mirror lumbar SDAVF in our patient presented in a more aggressive manner with symptoms progressing faster than in single or multi-level SDAVF. Our case demonstrates how this unique vascular anatomy may result in a diagnostic challenge, behaving in an occult way where typical findings are not seen on initial MRI scanning. We provide an argument for early vascular imaging which can result in the treatment of these lesions in a timely manner.

The ASPECT Hydrocephalus System: a non-hierarchical descriptive system for clinical use.

In patients with hydrocephalus, prognosis and intervention are based on multiple factors. This includes, but is not limited to, time of onset, patient age, treatment history, and obstruction of cerebrospinal fluid flow. Consequently, several distinct hydrocephalus classification systems exist. The International Classification of Diseases (ICD) is universally applied, but in ICD-10 and the upcoming ICD-11, hydrocephalus diagnoses incorporate only a few factors, and the hydrocephalus diagnoses of the ICD systems are based on different clinical measures. As a consequence, multiple diagnoses can be applied to individual cases. Therefore, similar patients may be described with different diagnoses, while clinically different patients may be diagnosed identically. This causes unnecessary dispersion in hydrocephalus diagnostics, rendering the ICD classification of little use for research and clinical decision-making. This paper critically reviews the ICD systems for scientific and functional limitations in the classification of hydrocephalus and presents a new descriptive system. We propose describing hydrocephalus by a system consisting of six clinical key factors of hydrocephalus: A (anatomy); S (symptomatology); P (previous interventions); E (etiology); C (complications); T (time-onset and current age). The "ASPECT Hydrocephalus System" is a systematic, nuanced, and applicable description of patients with hydrocephalus, with a potential to resolve the major issues of previous classifications, thus providing new opportunities for standardized treatment and research.

Assessment of patients with a Chiari malformation type I.

Introduction: The prevalence of Chiari malformation type I (CM-I) has been estimated as up to 1% of the general population. The majority of patients are asymptomatic and usually do not need treatment. Symptomatic patients, and some asymptomatic patients with associated conditions, may benefit from further assessment and treatment. Research question: The aim of this review was to describe the clinical and radiological assessment of patients presenting with a CM-I. Material and methods: A literature search was performed using the PubMed and Embase databases focused on clinical assessment and imaging techniques used to diagnose CM-I. Results: Following a complete clinical evaluation in patients with symptomatic CM-I and/or radiologically significant CM-I (tonsillar impaction, resulting tonsillar asymmetry and loss of CSF spaces), MRI of the brain and whole spine enables an assessment of the CM-I and potential associated or causative conditions. These include hydrocephalus, syringomyelia, spinal dysraphism, and tethered cord. Flow and Cine MRI can provide information on CSF dynamics at the craniocervical junction, and help in surgical decision-making. Hypermobility or instability at the upper cervical and craniocervical junction is less common and can be measured with CT imaging and flexion/extension or upright MRI. Discussion and conclusion: The majority of CM-I detected are incidental findings on MRI imaging of brain or spine, and do not require intervention. Once a radiological diagnosis and concern has been raised, clinical assessment by an appropriate specialist is required. A MRI brain and cervical spine is indicated in all radiologically labelled CM-I. In symptomatic patients or cases of radiologically significant CM-I, MRI of the brain and entire spine is indicated. Further investigations should be tailored to individuals' needs.

Safety analysis and complications of condylar screws in a single-surgeon series of 250 occipitocervical fusions.

OBJECTIVE: Condylar screw fixation is a rescue technique and an alternative to the conventional configuration of occipitocervical fusion. Condylar screws are utilized when previous surgical bone removal along the supraocciput has occurred which makes anchoring of a traditional barplate technically difficult or impossible. However, the challenging dissection of C0-1 necessary for condylar screw fixation and the concerns about possible complications have, thus far, prevented the acquisition of large surgical series utilizing occipital condylar screws. In the largest case series to date, this paper aims to evaluate the safety profile and complications of condylar screw fixation for occipitocervical fusion. METHODS: A retrospective safety and complication-based analysis of occipitocervical fusion via condylar screws fixation was performed. RESULTS: A total of 250 patients underwent occipitocervical fusions using 500 condylar screws between September 2012 and September 2018. No condylar screw pullouts, or vertebral artery impingements were observed in this series. The sacrifice of condylar veins during the dissection at C0-1 did not cause any venous stroke. Hypotrophic condyles were found in 36.4% (91 of the 250) cases and did not prevent the insertion of condylar screws. Two transient hypoglossal deficits occurred at the beginning of this surgical series and were followed by recovery a few months later. Corrective strategies were effective in preventing further hypoglossal injuries. CONCLUSIONS: This surgical series suggests that the use of condylar screws fixation is a relatively safe and reliable option for OC fusion in both adult and pediatric patients. Methodical dissection of anatomical landmarks, intraoperative imaging, and neurophysiologic monitoring allowed the safe execution of the largest series of condylar screws reported to date. Separate contributions will follow in the future to provide details about the long-term clinical outcome of this series.

Posterior fossa decompression with duraplasty in Chiari malformation type 1: a systematic review and meta-analysis.

BACKGROUND: Surgery for symptomatic Chiari type I malformation (CM-I) patients include posterior fossa decompression (PFD) involving craniectomy with or without dural opening, and posterior fossa decompression with duraplasty (PFDD). This review aims to examine the evidence to aid surgical decision-making. METHODS: A medical database search was expanded to include article references to identify all relevant published case series. Animal studies, editorials, letters, and review articles were excluded. A systemic review and meta-analysis were performed to assess clinical and radiological improvement, complications, and reoperation rates. RESULTS: Seventeen articles, containing data on 3618 paediatric and adult participants, met the inclusion criteria. In the group, 5 papers included patients that had the dura left open. PFDD is associated with better clinical outcomes (RR 1.24, 95% CI, 1.07 to 1.44; P = 0.004), but has a higher complication rate (RR 4.51, 95% CI, 2.01 to 10.11; P = 0.0003). In adults, clinical outcomes differences did not reach statistical significance (P = 0.07) but re-operation rates were higher with PFD (RR 0.17, 95% CI 0.03 to 0.86; P = 0.03), whilst in children re-operation rates were no different (RR 0.97, 95% CI 0.41 to 2.30; P = 0.94). Patients with a syrinx did better with PFDD (P = 0.02). No significant differences were observed concerning radiological improvement. CONCLUSIONS: In the absence of hydrocephalus and craniocervical region instability, PFDD provides better clinical outcomes but with higher risk. The use of PFD may be justified in some cases in children, and in the absence of a syrinx. To help with future outcome assessments in patients with a CM-I, standardization of clinical and radiological grading systems are required. TRIAL REGISTRATION: not required.

Subarachnoid haemorrhage secondary to traumatic intracranial aneurysm of the posterior cerebral circulation: case series and literature review.

BACKGROUND: To identify the clinical features, rebleed risk, timing and method of diagnosis, complications and outcome for subarachnoid haemorrhage (SAH) from traumatic intracranial aneurysm (TICA) of the posterior circulation. Subjects included 26 patients aged 3-54 (mean 24.8). METHODS: Case series and literature search to identify all reported cases. RESULTS: In our series, two of three cases were fatal as a result of rebleed, and one case had a good outcome with no deficit, following prompt diagnosis and embolisation. Our key findings from the literature review were: 30.7 % of patients were age 16 and under; 88 % had an acute drop in consciousness, 46 % in a delayed manner; the mean time to diagnosis was 7.5 days; initial cerebrovascular imaging was normal in 23 %; the rebleed rate was 23 %; 61 % required emergency diversion of cerebrospinal fluid; 11 % developed vasospasm requiring treatment; 19.2 % had deficits that rendered them unable to live independently. The mortality rate was 27 %. CONCLUSIONS: SAH from ruptured posterior circulation TICA is associated with significant morbidity and mortality. A high index of suspicion as well as prompt diagnosis, repeat imaging in selected cases, and treatment of any associated TICA can be crucial to a favourable outcome.

Third ventricular shape: a predictor of endoscopic third ventriculostomy success in pediatric patients.

OBJECT: The criteria for identifying patients in whom endoscopic third ventriculostomy (ETV) provides control of hydrocephalus remain in evolution. In particular, it is not clear when ETV would be effective if intraventricular obstruction is not found preoperatively. The authors postulated that 1) displacement of the third ventricle floor inferiorly into the interpeduncular cistern and displacement of the lamina terminalis anteriorly into the lamina terminalis cistern could predict clinical success of ETV, and 2) improvement in these displacements would correlate with the success of ETV. METHODS: Magnetic resonance imaging in 38 consecutive patients treated between 2004 and 2010 was reviewed to assess displacement of the lamina terminalis and third ventricular floor prior to and following ETV. Displacements of the floor and lamina terminalis were judged qualitatively and quantitatively, using a newly created index, the Third Ventricular Morphology Index (TVMI). The association between the aforementioned morphological features and clinical success of ETV was analyzed. RESULTS: Ninety-six percent of patients in whom the authors preoperatively observed displacement of the lamina terminalis and the third ventricular floor were successfully treated with ETV. Displacements of the third ventricular floor and lamina terminalis, as judged qualitatively, correlated with the clinical success of ETV. The TVMI correlated with the qualitative assessments of displacement. Postoperative decrease in the TVMI occurred in the majority of successfully treated patients. Changes in third ventricular morphology preceded changes in other measures of third and lateral ventricular volume following ETV. CONCLUSIONS: Assessment of third ventricular floor and lamina terminalis morphology is useful in predicting clinical success of ETV and in the follow-up in treated patients. The TVMI provided a quantitative assessment of the third ventricular morphology, which may be useful in equivocal cases and in research studies.

Spontaneous regression of septum pellucidum/forniceal pilocytic astrocytomas--possible role of Cannabis inhalation.

INTRODUCTION: Spontaneous regression of pilocytic astrocytoma after incomplete resection is well recognized, especially for cerebellar and optic pathway tumors, and tumors associated with Neurofibromatosis type-1 (NF1). The purpose of this report is to document spontaneous regression of pilocytic astrocytomas of the septum pellucidum and to discuss the possible role of cannabis in promoting regression. CASE REPORT: We report two children with septum pellucidum/forniceal pilocytic astrocytoma (PA) tumors in the absence of NF-1, who underwent craniotomy and subtotal excision, leaving behind a small residual in each case. During Magnetic Resonance Imaging (MRI) surveillance in the first three years, one case was dormant and the other showed slight increase in size, followed by clear regression of both residual tumors over the following 3-year period. Neither patient received any conventional adjuvant treatment. The tumors regressed over the same period of time that cannabis was consumed via inhalation, raising the possibility that the cannabis played a role in the tumor regression. CONCLUSION: We advise caution against instituting adjuvant therapy or further aggressive surgery for small residual PAs, especially in eloquent locations, even if there appears to be slight progression, since regression may occur later. Further research may be appropriate to elucidate the increasingly recognized effect of cannabis/cannabinoids on gliomas.

Microneurosurgical management of anterior choroid artery aneurysms.

OBJECTIVE: Anterior choroid artery aneurysms (AChAAs) constitute 2%-5% of all intracranial aneurysms. They are usually small, thin walled with one or several arteries originating at their base, and often associated with multiple aneurysms. In this article, we review the practical microsurgical anatomy, the preoperative imaging, surgical planning, and the microneurosurgical steps in the dissection and the clipping of AChAAs. METHODS: This review, and the whole series on intracranial aneurysms (IAs), are mainly based on the personal microneurosurgical experience of the senior author (J.H.) in two Finnish centers (Helsinki and Kuopio) that serve, without patient selection, the catchment area in Southern and Eastern Finland. RESULTS: These two centers have treated more than 10,000 patients with IAs since 1951. In the Kuopio Cerebral Aneurysm Database of 3005 patients with 4253 IAs, 831 patients (28%) had altogether 980 internal carotid artery (ICA) aneurysms, of whom 95 patients had 99 (2%) AChAAs. Ruptured AChAAs, found in 39 patients (41%), with median size of 6 mm (range = 2-19 mm), were associated with intracerebral hematoma (ICH) in only 1 (3%) patient. Multiple aneurysms were seen in 58 (61%) patients. CONCLUSIONS: The main difficulty in microneurosurgical management of AChAAs is to preserve flow in the anterior choroid artery originating at the base and often attached to the aneurysm dome. This necessitates perfect surgical strategy based on preoperative knowledge of 3 dimensional angioarchitecture and proper orientation during the microsurgical dissection.

Excision of vestibular schwannomas--is there a learning curve and how best to demonstrate it?

OBJECTIVE: To demonstrate the existence of a learning curve in a consultant neurosurgeon's performance in excising vestibular schwannomas by plotting the cumulative sum (CUSUM) chart. Also, to evaluate the influence of new technology in the form of the facial nerve monitor (FNM) and the KTP-532 Laser on surgical performance. METHOD: Analysis was carried out on a prospectively collected data series of 102 consecutive cases of vestibular schwannomas excisions between 1986 and 2000 by a single neurosurgeon using the retrosigmoid approach. The CUSUM score chart of the surgical outcomes across the series was plotted for all and large tumour sizes separately. The changes in CUSUM scores were assessed using statistical change-point analysis. Using the multivariate logistic regression analysis, we inspected the association between use of FNM and laser on outcome. RESULTS: After the first 27 cases and coinciding with the introduction of the FNM there was a clear change in the direction of the slope of the CUSUM chart, showing a clear improving trend in performance (p = 0.09). The same phenomenon was also seen when plotting the CUSUM chart for large tumours only, although this was not statistically significant. The use of FNM reduces the risk of bad House Brakmann-score by approximately 90% for all tumours (risk of bad outcome with FNM = 3.2% and without FNM = 26.7%, odds ratio = 0.10 and 95% confidence interval (0.02-0.61), p = 0.013) after adjusting for age at operation, but no significant association was seen with the use of laser. CONCLUSION: There appears to be a learning curve in the performance of a neurosurgeon. Compared to previous reports of sequential block analysis, the CUSUM method is less arbitrary and more transparent. The CUSUM is most useful as an audit tool that can help spare patients from undesirable learning curves, and help to demonstrate good standards in appraisal and revalidation.

Influence of light and time on bilirubin degradation in CSF spectrophotometry for subarachnoid haemorrhage.

AIM: Investigation of the influence of light on bilirubin degradation over time in cerebrospinal fluid (CSF) specimens from patients with computed tomography (CT) positive subarachnoid haemorrhage (SAH). METHODS: Twenty-nine CSF samples were analysed from 23 patients with CT-positive SAH. Samples were divided into two cohorts - one half being stored in the dark, the other in normal room light conditions. Samples were assayed by spectrophotometry 0, 1, 2, 6, 19, 24 and 48 h post-storage. Net bilirubin absorbance (NBA) was measured in absorbance units (AU) by determining the optical density at 476 nm. RESULTS: In 27 of 28 (96%) samples stored in light conditions and 21 of 29 (72%) samples stored in dark, a decline in the amount of bilirubin detected in CSF over time was observed. The rate of bilirubin degradation over 24 h for CSF samples stored in the light ranged from 0.0001 to 0.0048 AU/h (mean 0.0020 AU/h), and was significantly greater (p < 0.01) than the rate of degradation in the dark, which ranged from 0 to 0.0024 AU/h (mean 0.0005 AU/h). CONCLUSION: CSF bilirubin samples are susceptible to the same photodegradation as shown in serum bilirubin samples. The rate of degradation is not predictable or consistent. This photodegradation may potentially produce false-negative results in the diagnosis of SAH. If spectrophotometry cannot be carried out immediately, all such CSF samples should at least be centrifuged immediately, the supernatant protected from light as soon as possible and the collection and analysis times provided in the report.

Operative intervention for delayed symptomatic radionecrotic masses developing following stereotactic radiosurgery for cerebral arteriovenous malformations--case analysis and literature review.

CASE REPORT: We report two cases of operative intervention that was beneficial in the treatment of delayed symptomatic radionecrotic masses that had developed following stereotactic radiosurgery (SRS) using the gamma knife (GK) for the treatment of cerebral arteriovenous malformations (AVM). DISCUSSION: Case 1 involved a small craniotomy for decompression of a large cerebral multiloculated cyst, which had become symptomatic 84 months following gamma knife treatment for a left frontal lobe AVM. Case 2 involved surgical excision of an occipital radionecrotic mass 72 months following GK treatment for an occipital AVM. This patient had suffered from longstanding symptomatic cerebral oedema, which on occasions had become life threatening. Case 2 is also the first report of a radionecrotic mass occurring post-SRS for an AVM, which conversely appeared to demonstrate increased uptake on single photon emission computed tomography (SPECT) scan. The first literature review of such delayed symptomatic radionecrotic lesions is presented. There appears to be a late onset of symptoms (average 55 months, range 12-111 months) associated with such radionecrosis. Drainage of such cysts or excision of the mass lesion appears to be consistently beneficial to the patients and appears to be uncomplicated. CONCLUSION: We recommend early surgical intervention for such delayed symptomatic radionecrotic masses that do not resolve following non-operative management. We also recommend caution in interpretation of SPECT scan results when attempting to differentiate radionecrosis from neoplasia.

Is the routine placement of a CSF reservoir following endoscopic third ventriculostomy justified?

Endoscopic third ventriculostomy (ETV) is a well established treatment for selected cases of obstructive hydrocephalus. However, it does carry a significant rate of failure, which can be abrupt and life threatening. The present study analyses the benefits versus the risks of routine CSF reservoir insertion during ETV. Clinical data obtained from the medical records of patients from a single neurosurgical centre who underwent ETV between August 2002 and February 2007 were analysed retrospectively. A total of 34 records were available with follow-up ranging from 3-56 months (Median 26 months) and with patient age range between 6 months - 75 yrs (median 19 years). During this period, one neurosurgeon routinely placed reservoirs in all patients undergoing ETV (n = 34). In all instances of reservoir insertion, Ommaya reservoirs were used. The number of patients in which the reservoir was tapped for diagnostic and/or therapeutic reasons was quantified, and all complications resulting from reservoir placement recorded. ETV success was defined by a lack of subsequent need for cerebrospinal fluid diversion. In total 13 of 34 (38%) reservoirs inserted were tapped at a later date and there were no complications associated with their insertion. Tapping of reservoirs helped determine which patients required subsequent ventriculoperitoneal (VP) shunting. In at least one case reservoir tapping was carried out as an emergency and was a crucial intermediate intervention prior to further surgery. The overall success rate of ETV was 65% (95% CI, 49-81%) with four complications associated with ETV: short-term memory loss, psychosis, and two cases of post-operative seizures. These complications were not attributed to CSF reservoir insertion but the ETV procedure itself. The routine placement of CSF reservoir following ETV thus seems justified with respect to the observed benefits and lack of complications associated with its placement.