Lewis Thorne

Idiopathic intracranial hypertension: 120-day clinical, radiological, and manometric outcomes after stent insertion into the dural venous sinus

OBJECTIVE Idiopathic intracranial hypertension (IIH) is commonly associated with venous sinus stenosis. In recent years, transvenous dural venous sinus stent (DVSS) insertion has emerged as a potential therapy for resistant cases. However, there remains considerable uncertainty over the safety and efficacy of this procedure, in particular the incidence of intraprocedural and delayed complications and in the longevity of sinus patency, pressure gradient obliteration, and therapeutic clinical outcome. The aim of this study was to determine clinical, radiological, and manometric outcomes at 3-4 months after DVSS in this treated IIH cohort. METHODS Clinical, radiographic, and manometric data before and 3-4 months after DVSS were reviewed in this single-center case series. All venographic and manometric procedures were performed under local anesthesia with the patient supine. RESULTS Forty-one patients underwent DVSS venography/manometry within 120 days. Sinus pressure reduction of between 11 and 15 mm Hg was achieved 3-4 months after DVSS compared with pre-stent baseline, regardless of whether the procedure was primary or secondary (after shunt surgery). Radiographic obliteration of anatomical stenosis correlating with reduction in pressure gradients was observed. The complication rate after DVSS was 4.9% and stent survival was 87.8% at 120 days. At least 20% of patients developed restenosis following DVSS and only 63.3% demonstrated an improvement or resolution of papilledema. CONCLUSIONS Reduced venous sinus pressures were observed at 120 days after the procedure. DVSS showed lower complication rates than shunts, but the clinical outcome data were less convincing. To definitively compare the outcomes between DVSS and shunts in IIH, a randomized prospective study is needed.

Venous sinus stenting immediately reduces intracranial pressure in Idiopathic Intracranial Hypertension patients with venous sinus stenosis

Idiopathic Intracranial Hypertension (IIH) is characterised by an increased intracranial pressure (ICP) in the absence of any central nervous system disease or structural abnormality, and normal CSF composition. Management becomes complicated once surgical intervention is required. Venous sinus stenosis has been suggested as a possible aetiology for IIH. Venous sinus stenting has emerged as a possible interventional option. Evidence for venous sinus stenting is based on elimination of the venous pressure gradient and clinical response. There have been no studies demonstrating the immediate effect of venous stenting on ICP.

Intracranial pressure in patients with papilloedema

Papilloedema is a clinical manifestation of chronically raised intracranial pressure (ICP), often seen in idiopathic intracranial hypertension (IIH). However, the extent of intracranial hypertension required to produce papilloedema is not known. We compare ICP values in IIH patients who developed papilloedema and those who did not. We aim to identify a pathological ICP threshold predictive of the development of papilloedema in IIH patients.

Transtentorial Distortion Syndrome: Consistent Complication Following Lateral and Fourth Ventricular Shunting in Adults

BACKGROUND Complex hydrocephalus affecting lateral and fourth ventricles separately is occasionally managed with cerebrospinal fluid diversion via supratentorial and infratentorial ventricular catheters. The optimal configuration to reduce complications is currently unknown in adults. We describe a consistently similar clinical presentation of patients with complex hydrocephalus and a fourth ventricle separately drained by infratentorial shunt insertion. METHODS This was a retrospective single-center case series. Medical notes were reviewed for clinical presentation, brain imaging, and neurophysiologic tests results. All patients underwent intracranial pressure monitoring (ICPM). Outcomes were determined by ventricular appearance on brain imaging computed tomography and symptomatic improvements postoperatively. RESULTS Five adult patients referred to the hydrocephalus service had separate infratentorial and supratentorial shunt systems. A common clinical presentation was observed, including lower motor neuron facial palsy (confirmed with electrophysiology), ophthalmoplegia, dysarthria, impaired gait headache, and nausea. We refer to this as transtentorial distortion syndrome. Twenty-four-hour ICPM demonstrated clear low pressures. All patients underwent shunt revision connecting the transtentorial shunts via a Y-connector and the addition of a distal valve. All subjects had improved ventricular appearance on computed tomography scans post revision, and normalization of ICPM was observed. In the follow-up period of 6 months, no patient required further shunt revision. CONCLUSION To prevent transtentorial distortion syndrome, supratentorial and infratentorial shunt constructs in adults with encysted fourth ventricles should be similar to the shunt systems widely known in the pediatric population with Dandy-Walker syndrome (i.e., joint output to a single valve distal to the connection of the 2 proximal drainage catheters).

Neurosurgery and human immunodeficiency virus in the era of combination antiretroviral therapy: a review

Human immunodeficiency virus (HIV) is a global health problem. It renders the central nervous system susceptible to infectious and noninfectious diseases. HIV-positive individuals may present to neurosurgical services with brain lesions of unknown etiology. The differential diagnosis in these cases is broad, including opportunistic infections and malignancies, and investigation should be tailored accordingly. Opportunistic infections of the central nervous system can be complicated by hydrocephalus, and the management is pathogen dependent. Patients may also present to a neurosurgical service with conditions unrelated to their HIV status. This review outlines important conditions that cause brain lesions and hydrocephalus. It addresses the issues of diagnosis and intervention in HIV-positive patients in the era of combination antiretroviral therapy, while not ignoring the potential for opportunistic central nervous system infection in undiagnosed patients. The care of HIV-positive patients presenting to neurosurgical services requires a multidisciplinary approach, which is reflected in the authorship of this review, as well as in the guidance given.

NPH: are we giving up on patients with temporary improvement post shunt?

Normal pressure Hydrocephalus (NPH) is predominantly treated with a ventriculoperitoneal shunt (VPS) resulting in improvement in the Hakim triad (mobility, cognitive function, urinary continence). There are a population of patients who experience an improvement in symptoms post shunt insertion followed by a subsequent deterioration in their condition in the proceeding months / years. At our institution, a large volume (min 40ml) CSF withdrawal is made via the shunt reservoir in these patients, measuring pre/post mobility and cognitive function. Comparison is then made between pre/post results and if a clear improvement is seen, VP shunt surgical revision is offered.

Intracranial pressure guided management of patients with Chiari malformations presenting with headache: a paradigm shift?

Chiari malformation (CM) describes cerebellar tonsillar descent below the level of the foramen magnum. It is commonly associated with syringomyelia and often presents with headache (1). The conventional surgical treatment for symptomatic patients is foramen magnum decompression (FMD) (2) which carries a significant burden of operative morbidity (3). Altered cerebrospinal fluid (CSF) dynamics have been demonstrated in CM patients and CSF diversion has been used as an alternative treatment modality. Patients with chronic headache and radiological evidence of CM represent a therapeutic challenge. In our unit, these are primarily investigated with intracranial pressure (ICP) monitoring aiming to detect objective evaluation of CSF dynamics prior to surgical intervention.