Ahmed K. Toma

External ventricular drain insertion accuracy: is there a need for change in practice?

OBJECTIVEFree-hand insertion of an external ventricular drain (EVD) is a common emergency neurosurgical procedure, mostly performed for critically ill patients. Although EVD complications have been studied thoroughly, the accuracy of EVD positioning has been audited only occasionally. METHODSPost-EVD insertion computed tomographic scans performed in our unit over a 2-year period were analyzed for EVD tip location and intracranial catheter length. RESULTSA total of 183 post-EVD insertion scans were reviewed. Of those, 73 EVD tips (39.9%) were in the ipsilateral frontal horn of the lateral ventricle (the desired target); of those, 18 (25%) required EVD revision/reinsertion. Of the others, 35 (19.1%) were in the third ventricle, 33 (18%) in the body of the lateral ventricle, 19 (10.4%) in the subarachnoid space, 5 (2.7%) in the contralateral frontal horn, and 18 (9.8%) within the brain parenchyma. When the EVD tip was outside the desired target, 44 of the patients (40%) required EVD revision/reinsertion procedure (P = 0.0383). CONCLUSIONFree-hand insertion of an EVD is an inaccurate procedure, and further studies are required to assess the accuracy and feasibility of the routine use of neuronavigation, ultrasonography, or other guidance techniques and the possible implication of the decreasing revision rate, complications, and length of hospital stay.

Is there a difference in outcomes of patients with idiopathic intracranial hypertension with the choice of cerebrospinal fluid diversion site: A single centre experience

UNLABELLED The visual and headache outcomes in patients with idiopathic intracranial hypertension (IIH) undergoing cerebrospinal fluid diversion with a lumboperitoneal (LPS) or ventriculoperitoneal shunting (VPS) have not been well reported. The aims of this study were to: (a) to assess outcomes of CSF diversion in IIH, (b) to understand influence of the type of shunt in outcomes, and (c) to understand factors predisposing in shunt failure. METHODS The medical records of 34 patients who underwent cerebrospinal fluid diversion (CSFD) between 1996 and 2007 were retrieved and epidemiological and clinical data was collected. RESULTS The mean age was 35 (±7.9) years. Thirty-four patients underwent 63 shunt placements in total. 85% follow-up was achieved. The mean follow-up for the entire group was 28.9 (±31.8) months. Headaches improved more than visual disturbances. There was no significant difference between the groups that received a VPS and those receiving an LPS in both headache and visual outcomes. The rate of complications was 20.5% and the need for revision was 35% for the whole group. Patients with LPS suffered more complications and first time revisions than patients with VPS. No factor recorded could predict the need for revision or final outcomes. The shunts of patients receiving a VPS tend to survive longer than those receiving primarily an LPS, however the difference is not statistically significant. CONCLUSIONS Predicting which patients will improve is not possible at present. The influence of site diversion is not critical but patients with VPS have less complications and revisions than those receiving a LPS.

Ongoing search for diagnostic biomarkers in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus is a syndrome, which typically has a clinical presentation of gait/balance disturbance, often accompanied by cognitive decline and/or urinary incontinence. Its diagnosis is based on relevant history and clinical examination, appropriate imaging findings and physiological testing. The clinical picture of idiopathic normal pressure hydrocephalus may occasionally be difficult to distinguish from that of Alzheimers dementia, subcortical ischemic vascular dementia and Parkinsons disease. The aim of this article is to systematically review the literature from the last 29 years in order to identify cerebrospinal fluid (CSF) or imaging biomarkers that may aid in the diagnosis of the syndrome. The authors concluded that no CSF or imaging biomarker is currently fulfilling the criteria required to aid in the diagnosis of the condition. However, a few studies have revealed promising CSF and imaging markers that need to be verified by independent groups. The reasons that the progress in this field has been slow so far is also commented on, as well as steps required to apply the current evidence in the design of future studies within the field.

Rostrocaudal Dynamics of CSF Biomarkers

The rostrocaudal gradient (RCG) of markers present in cerebrospinal fluid (CSF) has not been studied adequately due to lack of appropriate control populations and ethical restrictions. The aim of this study is to understand the rostrocaudal gradient of CSF biomarkers. We contacted a study comparing CSF levels of seven biomarkers from cisternal (rostral) and lumbar (caudal) CSF obtained from patients with trigeminal neuralgia and tension-type headache. The RCGs of CSF/serum albumin ratio, 8-isoprostane. GFAP, total tau and beta amyloid protein were higher than one. The RCGs of lactate, VEGF and the heavy chain of neurofilament protein were lower than one. The study provides new values for several commonly examined markers of cisternal CSF. Knowledge of the RCG gradient of different CSF markers is important in interpreting studies reporting ventricular CSF values.

Use of cerebrospinal fluid amyloid-β and total tau protein to predict favorable surgical outcomes in patients with idiopathic normal pressure hydrocephalus

OBJECT The prognostic value of CSF biomarkers in patients with idiopathic normal pressure hydrocephalus (iNPH) has not been adequately studied to date. The aim of this study was to identify CSF markers of favorable surgical outcome in patients with iNPH undergoing the insertion of a ventriculoperitoneal shunt. METHODS Ventricular CSF was collected intraoperatively from 22 patients with iNPH and enzyme-linked immunosorbent assay was used to analyze the levels of amyloid-β 1-42 (Aβ(1-42)) and total tau protein. The Black grading scale was used to assess outcomes at 6 months. Receiver operating characteristic (ROC) curves were obtained and discriminant function analysis was undertaken to provide sensitivity and specificity figures for each marker as well as their combination. RESULTS The mean age of the patients was 71.45 years (± 9.5 years [SD]). Follow-up was achieved in 21 patients. Seventeen patients had a favorable outcome and 4 patients had unfavorable outcome at 6 months. An Aβ(1-42) level of 180 pg/ml had a sensitivity of 35% and a specificity of 20% for predicting a favorable outcome at 6 months. A total tau level of 767 pg/ml will have a sensitivity of 17% and a specificity of 20% for predicting a favorable outcome at 6 months. A combination of Aβ(1-42) and total tau levels predicted favorable outcomes with a sensitivity of 80% and specificity of 82.4%. CONCLUSIONS In this pilot study a combination of Aβ(1-42) levels and total tau protein levels predicted favorable surgical outcomes at 6 months with adequate accuracy to be of clinical use. Further study in a larger group with longer follow-up is warranted.

Cognitive, biochemical, and imaging profile of patients suffering from idiopathic normal pressure hydrocephalus

It has still not been clearly established whether the cognitive deficits of idiopathic normal pressure hydrocephalus (iNPH) are caused by a disturbance in cerebrospinal fluid (CSF) dynamics or an underlying metabolic disturbance.

Arterial Ischemic Stroke in Children

Acute ischemic stroke affects 3.3 of 100,000 children per year. The causes of AIS in children can be broadly divided into the following 6 categories: cardiac disese, sickle cell disease, moyamoya, arterial dissection, other arteriopathies, and other causes. Approximately 24% of the cases are classified as idiopathic. Magnetic resonance imaging (MRI) and cerebral angiography play an important role in the determining the causes of an AIS in children. Medical approaches, including anticoagulation, anti-inflammatories, and antiplatelet therapies, surgical revascularization and endovascular approaches may have a role in the management of AIS in children.

Spinal Dural Arteriovenous Fistulas: Clinical Experience with Endovascular Treatment as a Primary Therapy at 2 Academic Referral Centers

BACKGROUND AND PURPOSE: Spinal dural arteriovenous fistulas are a rare entity that, if left untreated, can lead to considerable morbidity with progressive spinal cord symptoms. The aim of this study was to evaluate the clinical outcome of patients with spinal dural arteriovenous fistulas that were primarily treated with endovascular embolization. MATERIALS AND METHODS: A retrospective review was performed of all patients from 1997–2010 who underwent treatment at 2 academic referral centers for a spinal dural arteriovenous fistula. Follow-up was performed by clinical examination, and functional status was measured by use of the Aminoff-Logue Disability Scale, McCormick classification grading, and mRS scores. The nonparametric Wilcoxon signed rank test was used to compare pretreatment and posttreatment Aminoff-Logue Disability Scale gait and micturition scores, McCormick classification grading, and mRS scores. P values < .05 were considered significant. RESULTS: A total of 38 patients were included. Five patients (2 endovascular, 3 surgical) were lost to follow-up and therefore were excluded from the analysis, 29 patients were initially treated from an endovascular approach (9 Onyx, 20 cyanoacrylate), and 4 patients were treated from a standard surgical approach. Five patients in the endovascular group subsequently underwent surgery for various reasons. The clinical improvements in the Aminoff-Logue Disability Scale gait and micturition scores, McCormick classification grading, and the mRS scores were statistically significant (P < .05, Wilcoxon signed rank test). CONCLUSIONS: We conclude that endovascular treatment of spinal dural arteriovenous fistulas can result in good clinical outcomes. Surgery remains the treatment of choice when safe embolization of the proximal radicular draining vein cannot be obtained or because the shunting artery of the spinal dural arteriovenous fistula also supplies the anterior spinal, posterior spinal, or a radiculomedullary artery.

Use of the proGAV shunt valve in normal-pressure hydrocephalus.

BACKGROUND: Overdrainage is a common complication associated with shunt insertion in normal-pressure hydrocephalus (NPH) patients. Using adjustable valves with antigravity devices has been shown to reduce its incidence. The optimal starting setting of an adjustable shunt valve in NPH is debatable. OBJECTIVE: To audit our single-center practice of setting adjustable valves. METHODS: We performed a retrospective review of clinical records of all NPH patients treated in our unit between 2006 and 2009 by the insertion of shunts with a proGAV valve, recording demographic and clinical data, shunt complications, and revision rates. Radiological reports of postoperative follow-up computed tomography scans of the brain were reviewed for detected subdural hematomas. RESULTS: A proGAV adjustable valve was inserted in 50 probable NPH patients between July 2006 and November 2009. Mean ± SD age was 76 ± 7 years. Mean follow-up was 15 months. The initial shunt setting was 6 ± 3 cm H2O, and the final setting was 4.9 ± 1.9 cm H2O. Nineteen patients required 24 readjustment procedures (readjustment rate, 38%; readjustment number, 0.48 times per patient). One patient (2%) developed delayed bilateral subdural hematoma after readjustment of his shunt valve setting as an outpatient. CONCLUSION: Starting with a low opening pressure setting on a proGAV adjustable shunt valve does not increase the chances of overdrainage complications and reduces the need for repeated readjustments.

Continuous intracranial pressure monitoring in pseudotumour cerebri: Single centre experience

Objective. Investigating pseudotumour cerebri (PTC) patients who do not fulfil the diagnostic criteria, or those presenting post-shunt insertion with recurrent symptoms and signs, with no clear evidence of shunt malfunction, present a diagnostic challenge. PTC patients who underwent continuous intracranial pressure (ICP) monitoring in our unit were reviewed retrospectively. Results. Twenty-six ICP monitoring procedures were done on 20 patients. Eleven patients had normal pressure, 2 overdrainage/low pressure, 11 underdrainage/high pressure and 2 variable pressures. On the basis of these results 12 patients were managed conservatively: 11 patients were referred to headache team and 1 patient had readjustment of an adjustable valve shunt setting; of those 3 patients had improved symptoms on their first post-operative clinic review. On the other hand, 14 patients had surgery: 5 had shunt revision and 9 had shunt insertion; of those 5 patients improved. Conclusion. ICP monitoring using an intraparenchymal probe is a safe and effective diagnostic technique in investigating PTC when indicated. A multidisciplinary approach achieves best results in terms of successful management and follow-up.