Venous sinus stenting as a treatment approach in patients with idiopathic intracranial hypertension and encephaloceles

Idiopathic Intracranial Venous Hypertension: Toward a Better Understanding of Venous Stenosis and the Role of Stenting in Idiopathic Intracranial Hypertension

BACKGROUND

Venous sinus stenosis, typically at the junction of the transverse and sigmoid sinus, is increasingly recognized as a contributor to the pathophysiology of idiopathic intracranial hypertension (IIH), whether it be the intrinsic type that does not reverse with normalization of intracranial pressure or the extrinsic type, which does. Efforts to treat the stenosis and reduce the associated transstenotic gradient through placement of a stent at the site of stenosis have been studied over the past 2 decades, primarily through retrospective studies, with variable emphasis on formal visual testing and direct assessment of poststent opening pressure. Most studies have presented evidence for utilization of stenting as an alternative to cerebrospinal fluid shunting or optic nerve sheath fenestration in patients with IIH who harbor the stenosis and are refractory to or intolerant of intracranial pressure-lowering medications, but an assessment of the current data is needed to better understand the role of stenting for this patient population.

EVIDENCE ACQUISITION

A search in PubMed was made for "IIH," "papilledema," and "venous stenting." Data pre and post stenting, including symptoms attributable to IIH, intracranial pressure, papilledema, retinal nerve fiber layer thickening on optical coherence tomography, and visual field assessment (mean deviation), were collected. Need for retreatment and complications were assessed among all studies. Studies using stenting for special circumstances, such as cerebrospinal leaks or for stenosis along anomalous vessels, were reviewed.

RESULTS

In total, 49 studies (45 retrospective and 4 prospective) and 18 case reports (with 3 or less patients) were found and included in the analysis, for a total of 1,626 patients. In 250 patients in whom poststent intracranial pressure was measured, the mean value was 19.7 cm H 2 O, reduced from a mean of 33 cm H 2 O. Transient visual obscurations resolved in 79.6% of 201 patients who complained of it, pulsatile tinnitus resolved in 84.7% of 515, diplopia resolved in 93% of 86 patients, and nonspecific visual symptoms such as "blurry vision" improved in 76.2% of 537 patients. Headaches resolved in 36% and improved in a further 40.7% of 1,105 patients in whom they were documented before stenting. Of 1,116 with papilledema, 40.8% demonstrated resolution and 38.2% improvement. The mean retinal nerve fiber layer thickness improved from 170.2 µm to 89.2 µm among 402 eyes in which optical coherence tomography was used to measure it. Among 135 eyes in which formal visual fields were performed pre and post stenting, the prestent average mean deviation of -7.35 dB improved to -4.72 dB after stenting. Complications associated with stenting included in-stent stenosis or thrombosis, subdural hematoma, intracerebral hematoma, cerebral edema, stent migration, and death. A recurrence of symptoms requiring a follow-up surgical intervention occurred in 9%.

CONCLUSIONS

A growing body of evidence supports the use of venous sinus stenting as a viable option for medically refractory IIH, especially when papilledema threatens visual function. Complication and failure rates seem to be similar to alternative surgical approaches, although serious neurological sequalae can rarely occur. Emerging studies evaluating stent type, including novel stents designed for use in the venous system, may help improve ease of the procedure and long-term success rates. Prospective head-to-head studies are needed to better understand the performance of stenting compared with other interventions.

Reversible Bilateral Transverse Sinus Occlusion Treated by Lumboperitoneal Shunt in Idiopathic Intracranial Hypertension: A Case Report

We report a patient with idiopathic intracranial hypertension (IIH) with bilateral transverse sinus occlusion treated by a lumboperitoneal shunt. A 45-year-old woman presented with visual disturbance and chronic headache. Magnetic resonance (MR) venography and three-dimensional computed tomography angiography (3D-CTA) showed occlusion of both transverse sinuses. After the surgery, MR venography and 3D-CTA showed no blockages in both transverse sinuses. This phenomenon reveals that obstruction of the bilateral transverse sinus is a consequence of intracranial hypertension, not just a single cause. Since many patients have an obstruction or stenosis of the venous sinus, there are some reports of endovascular treatment. Sinus reconstruction is usually effective, but it is not effective in some cases. Reversal of sinus occlusion suggests that endovascular therapy for IIH is inadequate in some cases.

Arachnoid Granulation Causing Unilateral Pulsatile Tinnitus Treated With Dural Venous Sinus Stenting

BACKGROUND

Large arachnoid granulations that protrude into dural venous sinuses and partially obstruct outflow are an underappreciated etiology of pulsatile tinnitus (PT). Endovascular dural venous sinus stenting is thought to diminish turbulent venous outflow and may relieve obstruction caused by arachnoid granulations.

METHODS

Four patients at two institutions were evaluated for unilateral PT. Magnetic resonance imaging and digital subtraction angiography revealed moderate-to-severe stenoses from large arachnoid granulations within the implicated transverse sinus. All patients underwent venous manometry and endovascular sinus stenting.

RESULTS

All patients experienced immediate and complete remission of their PT. Stenoses were relieved by a mean of 93% by Warfarin-Aspirin Symptomatic Intracranial Disease criteria. There were no procedural or periprocedural complications. All patients continued to report complete symptom resolution at a mean of 8-month follow-up.

CONCLUSIONS

PT from arachnoid granulations are an underappreciated pathomechanism. Endovascular dural venous sinus stenting is an effective intervention for treating unilateral PT secondary to large arachnoid granulation.

Brain herniation (encephalocele) into arachnoid granulations: prevalence and association with pulsatile tinnitus and idiopathic intracranial hypertension

PURPOSE

Brain herniation into arachnoid granulations (BHAG) of the dural venous sinuses is a recently described finding of uncertain etiology. The purpose of this study was to investigate the prevalence of BHAG in a cohort of patients with pulsatile tinnitus (PT) and to clarify the physiologic and clinical implications of these lesions.

METHODS

The imaging and charts of consecutive PT patients were retrospectively reviewed. All patients were examined with MRI including pre- and post-contrast T1- and T2-weighted sequences. Images were reviewed separately by three blinded neuroradiologists to identify the presence of BHAG. Their location, signal intensity, size, presence of arachnoid granulation, and associated dural venous sinus stenosis were documented. Clinical records were further reviewed for idiopathic intracranial hypertension, history of prior lumbar puncture, and opening pressure.

RESULTS

Two hundred sixty-two consecutive PT patients over a 4-year period met inclusion criteria. PT patients with BHAG were significantly more likely to have idiopathic intracranial hypertension than PT patients without BHAG (OR 4.2, CI 1.5-12, p = 0.006). Sixteen out of 262 (6%) patients were found to have 18 BHAG. Eleven out of 16 (69%) patients had unilateral temporal or occipital lobe herniations located in the transverse sinus or the transverse-sigmoid junction. Three out of 16 (19%) patients had unilateral cerebellar herniations and 2/16 (13%) patients had bilateral BHAG.

CONCLUSION

In patients with PT, BHAG is a prevalent MRI finding that is strongly associated with the clinical diagnosis of IIH. The pathogenesis of BHAG remains uncertain, but recognition should prompt comprehensive evaluation for IIH.

Encephalocele-Associated Drug-Resistant Epilepsy of Adult Onset: Diagnosis, Management, and Outcomes

Epileptogenic encephaloceles, most frequently located in the temporal lobe, are a known lesional cause of focal epilepsy. Data are limited regarding diagnosis, management, and outcomes of patients with epilepsy in the setting of an encephalocele, because the literature mostly comprises case reports, case series, and retrospective studies. We conducted a broad literature review for articles related to encephaloceles and epilepsy regardless of level of evidence. Hence, this review provides a summary of all available literature related to the topic. Thirty-six scientific reports that fulfilled our inclusion criteria were reviewed. Most reported patients presented with focal impaired awareness seizures and/or generalized tonic-clonic seizures. Although most of the encephaloceles were located in the temporal lobe, we found 5 cases of extratemporal encephaloceles causing epilepsy. More patients who underwent either lesionectomy or lobectomy were seizure free at time of follow-up. In the temporal lobe, there is no clear consensus on the appropriate management for epileptic encephaloceles and further studies are warranted to understand the associated factors and long-term outcomes associated with epilepsy secondary to encephaloceles. Reported data suggest that these patients could be manageable with surgical procedures including lesionectomy or lobectomy. In addition, because of data suggesting similar results between procedures, a more conservative surgery with lesionectomy and defect repair rather than a lobectomy may have lower surgical risks and similar seizure freedom.

Transverse sinus stenting for treatment of papilloedema secondary to a large brain herniation into a dural venous sinus with associated tectal plate lesion: Case report and literature review

Brain herniation into a dural venous sinus is a rare entity of unknown clinical significance without a clear relationship to raised intracranial pressure. There are yet to be detailed reports of interventional neuroradiology procedures involving sinus stenting across brain herniations. The authors of this paper present the first case of a stent placed across a large brain herniation into the transverse sinus in a patient with a tectal plate lesion and features of chronically raised intracranial pressure. This case demonstrates objective resolution of papilloedema and venous sinus pressure gradient at six months without complication.