Association of Extent of Transverse Sinus Stenosis With Cerebral Glymphatic Clearance in Patients With Idiopathic Intracranial Hypertension.

BACKGROUND AND OBJECTIVES: Idiopathic intracranial hypertension (IIH) is a neurologic disorder characterized by symptoms of elevated intracranial pressure in the absence of a clear cause. There is a developing theory that IIH may, in part, be related to abnormal cerebral glymphatic clearance. In addition, transverse sinus stenosis (TSS) is a common finding in IIH of unclear pathophysiologic significance. Similarly, whether or not TSS is associated with glymphatic outflow in IIH is unknown. The aim of this investigation was to explore the possible association between glymphatic outflow and extent of TSS in patients with IIH. METHODS: The study cohort consisted of patients with IIH and healthy controls who were retrospectively identified from our tertiary care institution located in upstate New York from 2016 to 2023. Patients with IIH were included if they had brain MRIs completed with sufficient sequences for analysis. Brain MRIs were computationally analyzed using diffusion tensor imaging analysis along the perivascular space technique to quantify the glymphatic function in patients with IIH. Glymphatic clearance, the primary outcome, was then correlated with the degree of TSS on MR venography using 2 different scoring systems, the 'Farb score' and 'Carvalho score.' RESULTS: Overall, 81 patients with IIH (70 [86%] female, mean age 29.8 years [SD: 8.2 years], mean BMI 41 [SD: 8.4]) and 10 normal controls were identified with sufficient imaging. Based on the Carvalho TSS score, IIH patients without TSS had significantly lower glymphatic clearance than healthy controls (mean ALPS index: 1.196 [SD: 0.05] vs 1.238 [SD: 0.04], respectively; p = 0.018). Furthermore, IIH patients with TSS had significantly lower glymphatic outflow than healthy controls (1.129 [SD: 0.07] vs 1.238 [SD: 0.04], respectively; p < 0.0001) and IIH patients without TSS (1.129 [SD: 0.07] vs 1.196 [SD: 0.05], respectively; p < 0.0001). In addition, there was a significant association between increasing extent of TSS and declining glymphatic clearance (p < 0.0001, R = 0.62). Finally, IIH patients with severe TSS had significantly lower glymphatic flow than IIH patients with mild stenosis (1.121 [SD: 0.07] vs 1.178 [SD: 0.05], respectively; p < 0.0001). These findings were similarly recapitulated using the Farb TSS scoring system. DISCUSSION: These preliminary findings suggest that the extent of TSS is associated with the degree of glymphatic clearance in IIH, providing novel insights into IIH pathophysiology. Further research is required to clarify the possible causal relationship between TSS and impaired glymphatic clearance in IIH.

Can optic disc vessel density help in cases of residual disc elevation after shunt surgery in cases of idiopathic intracranial hypertension?

AIM: To detect if we can use the reduction in the optic disc vessel density as an indicator to the reduction in intracranial tension in patients with residual optic disc elevation after shunt surgery as fundus examination in those cases is not conclusive. PATIENTS AND METHOD: 21 patients with papilledema due to idiopathic intracranial hypertension underwent shunt surgery. Full neurological and ophthalmological assessments were done. The optic disc vessel density was measured before and 3 months after surgery. Patients were then divided according to the resolution of papilledema into 2 groups: 1) Residual disc elevation group. 2) Completely resolved disc edema group. CSF pressure was measured via lumber puncture preoperative for all patients and 3 months post-operative only for patients with residual disc edema. A comparison between both groups was done. RESULTS: There was a highly statistically significant difference between the two groups as regard the papilledema grade (the residual disc elevation group had a higher grade of papilledema) with P-value=0.000. As regard the difference in the preoperative optic disc vessel density between the two groups, there were statistically significant differences (optic disc vessel density was more in the residual disc elevation group). As regard the postoperative optic disc vessel density, there were non-significant differences between the two groups in whole image, inside disc and peripapillary vessel density (either in macro or microvasculature). CONCLUSION: The optic disc vessel density decreased with normal postoperative CSF opening pressure in cases with residual disc elevation postoperatively. Thus, in cases of residual optic disc swelling after shunt surgery, we can detect the reduction of intracranial pressure by the reduction in the optic disc vessel density which is a safe non-invasive technique. That may help in cases of residual disc elevation.

Impact of Ramadan fasting on vision and headache-related quality of life in women with idiopathic intracranial hypertension: A prospective observational study.

BACKGROUND: Ramadan fasting is an obligatory religious practice for Muslims. However, research data on the effect of Ramadan on idiopathic intracranial hypertension (IIH) symptoms are lacking. This study aimed to study the effect of Ramadan fasting on the severity of headache and visual symptoms and related quality-of-life activities. METHODS: This prospective cohort study targeted females diagnosed with IIH (n = 102) who were eligible to fast for Ramadan in 2023. The patients were recruited from the Neurology Clinic in Beni-Suef University Hospital, Egypt. Body mass index (BMI), monthly headache days and intensity of headache attacks, six-item Headache Impact Test (HIT-6), and the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) scores during Ramadan were compared to those during the (non-fasting) month of Shaaban, the preceding month to Ramadan. RESULTS: There was a significant increase in the BMI of patients with IIH in Ramadan compared to the (non-fasting) month of Shaaban, at a median (interquartile range [IQR]) of 30.5 (26.6-35.8) kg/m2 and 30.1 (26.6-35.2) kg/m2, respectively (p = 0.002). The median (IQR) value of monthly headache days was significantly increased during Ramadan in comparison to the (non-fasting) month of Shaaban, at 20 (11.5-30) vs. 15 (10-25) (p < 0.001). There was a statistically significant worsening in the visual analog scale (VAS) scores (median [IQR] 7 [5-8] vs. 6.5 [5-8]), HIT-6 scores (median [IQR] 61 [58-67] vs. 59 [53-61.5]), and NEI-VFQ-25 total scores (median [IQR] 1312.5 [1238.8-1435] vs 1290 [1165-1417.5]) during Ramadan in comparison to the (non-fasting) month of Shaaban (p < 0.001 for all comparisons). The change in BMI in Ramadan was positively correlated with the change in monthly headache days (r = 0.24, p = 0.014), VAS (r = 0.20, p = 0.043), HIT-6 (r = 0.25, p = 0.010) and NEI-VFQ-25 scores (r = 0.24, p = 0.016). CONCLUSION: Ramadan fasting had an aggravating effect on headache, visual symptoms, and related quality-of-life activities, which might be attributed to weight gain during this month. Whether proper nutritional management to prevent weight gain during Ramadan may help mitigate this worsening effect is a mission of future studies.

Rebound Intracranial Hypertension.

PURPOSE OF REVIEW: Rebound intracranial hypertension (RIH) is a post-procedural treatment complication in patients with spontaneous intracranial hypotension (SIH) characterized by transient high-pressure headache symptoms. This article reviews the epidemiology, clinical features, risk factors, and treatment options for RIH. RECENT FINDINGS: This article discusses how changes in underlying venous pressure and craniospinal elastance can explain symptoms of RIH, idiopathic intracranial hypertension (IIH), and SIH. The pathophysiology of RIH provides a clue for how high and low intracranial pressure disorders, such as IIH and SIH, are connected on a shared spectrum.

Interrelation Between Cerebrospinal Fluid Pressure, Intracranial Morphology and Venous Hemodynamics Studied by 4D Flow MRI.

PURPOSE: To quantify the effects of CSF pressure alterations on intracranial venous morphology and hemodynamics in idiopathic intracranial hypertension (IIH) and spontaneous intracranial hypotension (SIH) and assess reversibility when the underlying cause is resolved. METHODS: We prospectively examined venous volume, intracranial venous blood flow and velocity, including optic nerve sheath diameter (ONSD) as a noninvasive surrogate of CSF pressure changes in 11 patients with IIH, 11 age-matched and sex-matched healthy controls and 9 SIH patients, before and after neurosurgical closure of spinal dural leaks. We applied multiparametric MRI including 4D flow MRI, time-of-flight (TOF) and T2-weighted half-Fourier acquisition single-shot turbo-spin echo (HASTE). RESULTS: Sinus volume overlapped between groups at baseline but decreased after treatment of intracranial hypotension (p = 0.067) along with a significant increase of ONSD (p = 0.003). Blood flow in the middle and dorsal superior sagittal sinus was remarkably lower in patients with higher CSF pressure (i.e., IIH versus controls and SIH after CSF leak closure) but blood flow velocity was comparable cross-sectionally between groups and longitudinally in SIH. CONCLUSION: We were able to demonstrate the interaction of CSF pressure, venous volumetry, venous hemodynamics and ONSD using multiparametric brain MRI. Closure of CSF leaks in SIH patients resulted in symptoms suggestive of increased intracranial pressure and caused a subsequent decrease of intracranial venous volume and of blood flow within the superior sagittal sinus while ONSD increased. In contrast, blood flow parameters from 4D flow MRI did not discriminate IIH, SIH and controls as hemodynamics at baseline overlapped at most vessel cross-sections.

Effect of glucagon like peptide-1 receptor agonist exenatide, used as an intracranial pressure lowering agent, on cognition in Idiopathic Intracranial Hypertension.

BACKGROUND: Cognitive function can be affected in conditions with raised intracranial pressure (ICP) such as idiopathic intracranial hypertension (IIH). Drugs used off label to treat raised ICP also have cognitive side effects, underscoring the unmet need for effective therapeutics which reduce ICP without worsening cognition. The Glucagon Like Peptide-1 (GLP-1) receptor agonist, exenatide, has been shown to significantly reduce ICP in IIH, therefore this study aimed to determine the effects of exenatide on cognition in IIH. METHODS: This was an exploratory study of the IIH:Pressure trial (ISTCRN 12678718). Women with IIH and telemetric ICP monitors (n = 15) were treated with exenatide (n = 7) or placebo (n = 8) for 12 weeks. Cognitive function was tested using the National Institute of Health Toolbox Cognitive Battery at baseline and 12 weeks. RESULTS: Cognitive performance was impaired in fluid intelligence ((T-score of 50 = population mean), mean (SD) 37.20 (9.87)), attention (33.93 (7.15)) and executive function (38.07 (14.61)). After 12-weeks there was no evidence that exenatide compromised cognition (no differences between exenatide and placebo). Cognition improved in exenatide treated patients in fluid intelligence (baseline 38.4 (8.2), 12 weeks 52.9 (6.6), p = 0.0005), processing speed (baseline 43.7 (9.4), 12 weeks 58.4 (10.4), p = 0.0058) and episodic memory (baseline 49.4 (5.3), 12 weeks 62.1 (13.2), p = 0.0315). CONCLUSIONS: In patients with raised ICP due to IIH, exenatide, a drug emerging as an ICP lowering agent, does not adversely impact cognition. This is encouraging and has potential to be relevant when considering prescribing choices to lower ICP.

Lumbar Puncture for Diagnosis of Idiopathic Intracranial Hypertension in Typical Patients.

BACKGROUND: Patients with typical features of pseudotumor cerebri syndrome (PTCS) must undergo lumbar puncture (LP) to demonstrate elevated opening pressure and cerebrospinal fluid (CSF) analysis to rule out alternative diagnoses. As LP may be associated with significant morbidity, this study aims to determine its necessity in diagnosing typical PTCS. METHODS: Retrospective chart review at 3 university-based neuro-ophthalmology practices included women aged 18-45 years with body mass index >25, papilledema, negative neuroimaging, and who met criteria for PTCS or probable PTCS. RESULTS: One hundred fifty-six patients were enrolled. Seven (4.5%) had clinically insignificant CSF abnormalities. No diagnoses or management changed based on LP/CSF results. CONCLUSION: LP may not be routinely required in the initial evaluation of typical patients with PTCS evaluated by experienced clinicians We caution, however, that further prospective study is required to determine potential risks and benefits of LP as a tool in the diagnosis of IIH before recommending general practice changes.

Analysis of the Peripapillary Choroidal Vascular Characteristics in Papilledema Associated with Pseudotumor Cerebri.

SIGNIFICANCE: Choroidal vascularity index measured by image binarization method from peripapillary optical coherence tomography sections has been found significantly lower in papilledema patients than healthy controls. PURPOSE: The purpose of this study was to compare peripapillary choroidal parameters in papilledema patients with control subjects. METHODS: Peripapillary spectral domain optical coherence tomography scans of 34 patients with papilledema and 34 healthy controls are acquired for the study. Images are binarized with the ImageJ software (National Institutes of Health, Bethesda, MD) to calculate total choroidal area, stromal area, luminal area, and choroidal vascularity index. RESULTS: Total choroidal area, luminal area, and choroidal vascularity were significantly lower in papilledema patients compared with healthy controls on right (1.343 ± 0.286 vs. 1.694 ± 0.344, P < .001; 0.880 ± 0.209 vs. 1.167 ± 0.255, P < .001; 65.28 ± 2.99% vs. 68.68 ± 2.81%, P < .001, respectively) and left eyes (1.376 ± 0.308 vs. 1.647 ± 0.339, P < .001; 0.899 ± 0.231 vs. 1.134 ± 0.237, P < .001; 64.92 ± 3.44 vs. 68.84 ± 3.23, P < .001, respectively). No difference was found between active and remitted stages of papilledema in terms of choroidal parameters. CONCLUSIONS: Peripapillary total choroidal area, luminal area, and choroidal vascularity index are significantly reduced in patients with papilledema. These parameters might be beneficial tools for evaluating choroidal vascularity in papilledema quantitatively and differential diagnosis for optic disc edema.

Systemic and adipocyte transcriptional and metabolic dysregulation in idiopathic intracranial hypertension.

BACKGROUNDIdiopathic intracranial hypertension (IIH) is a condition predominantly affecting obese women of reproductive age. Recent evidence suggests that IIH is a disease of metabolic dysregulation, androgen excess, and an increased risk of cardiovascular morbidity. Here we evaluate systemic and adipose specific metabolic determinants of the IIH phenotype.METHODSIn fasted, matched IIH (n = 97) and control (n = 43) patients, we assessed glucose and insulin homeostasis and leptin levels. Body composition was assessed along with an interrogation of adipose tissue function via nuclear magnetic resonance metabolomics and RNA sequencing in paired omental and subcutaneous biopsies in a case-control study.RESULTSWe demonstrate an insulin- and leptin-resistant phenotype in IIH in excess of that driven by obesity. Adiposity in IIH is preferentially centripetal and is associated with increased disease activity and insulin resistance. IIH adipocytes appear transcriptionally and metabolically primed toward depot-specific lipogenesis.CONCLUSIONThese data show that IIH is a metabolic disorder in which adipose tissue dysfunction is a feature of the disease. Managing IIH as a metabolic disease could reduce disease morbidity and improve cardiovascular outcomes.FUNDINGThis study was supported by the UK NIHR (NIHR-CS-011-028), the UK Medical Research Council (MR/K015184/1), Diabetes UK, Wellcome Trust (104612/Z/14/Z), the Sir Jules Thorn Award, and the Midlands Neuroscience Teaching and Research Fund.

The relationship between cerebral blood flow and venous sinus pressure: can hyperemia induce idiopathic intracranial hypertension?

BACKGROUND: It has been shown that idiopathic intracranial hypertension (IIH) in children is associated with cerebral hyperemia, which induces an increase in cerebral venous pressure. The current literature suggests venous pressure scales with blood flow in a linear fashion, however, a linear relationship would not raise the pressure high enough to induce IIH. There is, however, some evidence to suggest that this relationship could be quadratic in nature. The purpose of this paper is to characterize the relationship between cerebral blood flow and the pressure drop across the cerebral venous system. METHODS: 10 CT venogram data sets were collected for this study, with 5 useable geometries created. Computational fluid dynamics (CFD) models were generated using these geometries, with 10 simulations conducted per patient. The flow rates tested ranged from 200 mL/min to 2000 mL/min. 3D pressure and velocity streamline distributions were created and analyzed for each CFD model, with pressure drops across the cerebral venous system determined. The effective and hydraulic diameters were determined at the superior sagittal sinus, transverse sinus and both proximal and distal sigmoid sinuses. RESULTS: A quadratic relationship between blood flow and sinus pressure was found, with correlations of 0.99 or above in all five patients. The presence of vortical blood flow was found to explain this trend, with fluid curl and pressure drop correlations being above 0.97. This suggests that the presence of high blood flow should be considered in the diagnostic workup of IIH. CONCLUSIONS: The cerebral venous sinus blood flow and pressure response relationship are quadratic in nature, with the major cause of this being the degree of rotation induced in the flow. The elevated blood flow found in children with IIH can explain the increased ICP that is found, secondary to the increase in venous pressure that develops.

COVID-19 and chronic fatigue syndrome: Is the worst yet to come?

There has been concern about possible long-term sequelae resembling myalgic encephalomyelitis/chronic fatigue syndrome in COVID-19 patients. Clarifying the mechanisms underlying such a "post-COVID-19 fatigue syndrome" is essential for the development of preventive and early treatment methods for this syndrome. In the present paper, by integrating insights pertaining to the glymphatic system and the nasal cerebrospinal fluid outflow pathway with findings in patients with chronic fatigue syndrome, idiopathic intracranial hypertension, and COVID-19, I provide a coherent conceptual framework for understanding the pathophysiology of post-COVID-19 fatigue syndrome. According to this hypothesis, this syndrome may result from damage to olfactory sensory neurons, causing reduced outflow of cerebrospinal fluid through the cribriform plate, and further leading to congestion of the glymphatic system with subsequent toxic build-up within the central nervous system. I further postulate that patients with post-COVID-19 fatigue syndrome may benefit from cerebrospinal fluid drainage by restoring glymphatic transport and waste removal from the brain. Obviously, further research is required to provide further evidence for the presence of this post-viral syndrome, and to provide additional insight regarding the relative contribution of the glymphatic-lymphatic system to it. Other mechanisms may also be involved. If confirmed, the glymphatic-lymphatic system could represent a target in combating post-COVID-19 fatigue syndrome. Moreover, further research in this area could also provide new insights into the understanding of chronic fatigue syndrome.

Telemetric monitoring in idiopathic intracranial hypertension demonstrates intracranial pressure in a case with sight-threatening disease.

The understanding of raised intracranial pressure (ICP) is increasing with the directed use of intracranial telemetric ICP monitors. This case uniquely observed ICP changes by telemetric monitoring in a patient with idiopathic intracranial hypertension (IIH), who developed rapid sight-threatening disease. A lumbar drain was inserted, as a temporising measure, and was clamped prior to surgery. This resulted in a rapid rise in ICP, which normalised after insertion of a ventriculoperitoneal shunt. This case highlighted the utility of the ICP monitor and the lumbar drain as a temporising measure to control ICP prior to a definitive procedure as recommended by the IIH consensus guidelines.

Reductions in bilateral transverse sinus pressure gradients with unilateral transverse venous sinus stenting for idiopathic intracranial hypertension.

BACKGROUND: Venous sinus stenting is an effective treatment for papilledema associated with idiopathic intracranial hypertension (IIH). It is unclear whether unilateral transverse-sigmoid sinus (TSS) stenting adequately decompresses the contralateral TSS system in cases of bilateral transverse sinus stenosis. The objective of this study was to compare changes in bilateral TSS pressure gradients following unilateral TSS stenting in a series of patients with IIH. METHODS: Consecutive patients from a single institution who underwent venous sinus stenting for IIH with measurement of bilateral pressure gradients before and after stenting for IIH were enrolled. Pressure gradients in both TSS pre- and post-stenting were measured during the procedure. The TSS with the highest gradient was stented. Changes in TSS pressure gradients following stent placement were calculated for both TSS. Mean changes in pressure gradients of ipsilateral and contralateral TSS were calculated. RESULTS: Sixteen patients with IIH who underwent TSS stenting were included. All were female. Mean age was 36.4 years. The right-sided TSS was the stented side in 12 (75.0%) patients. The mean pre-stent pressure gradient of the ipsilateral TSS was 19.3 mmHg (SD=10.8), which was reduced to a mean of 3.8 mmHg (3.4) following stent placement (P =<0.0001). On the contralateral (non-stented) side, the mean pre-stent gradient of 15.1 mmHg (7.5) was reduced to a mean of 7.8 mmHg (6.6) following stenting (P=0.006). CONCLUSIONS: The use of a single stent provides some venous decompression of the contralateral non-stented stenosis in most cases of IIH treated with endovascular therapy.

Idiopathic Intracranial Hypertension: Glymphedema of the Brain.

BACKGROUND: During the last decade, our understanding of cerebrospinal fluid (CSF) physiology has dramatically improved, thanks to the discoveries of both the glymphatic system and lymphatic vessels lining the dura mater in human brains. EVIDENCE ACQUISITION: We detail the recent basic science findings in the field of CSF physiology and connect them with our current understanding of the pathophysiology of idiopathic intracranial hypertension (IIH). RESULTS: Transverse sinus (TS) stenoses seem to play a major causative role in the symptoms of IIH, as a result of a decrease in the pressure gradient between the venous system and the subarachnoid space. However, the intracranial pressure can be highly variable among different patients, depending on the efficiency of the lymphatic system to resorb the CSF and on the severity of TS stenoses. It is likely that there is a subclinical form of IIH and that IIH without papilledema is probably under-diagnosed among patients with chronic migraines or isolated tinnitus. CONCLUSIONS: IIH can be summarized in the following pathological triad: restriction of the venous CSF outflow pathway-overflow of the lymphatic CSF outflow pathway-congestion of the glymphatic system. To better encompass all the stages of IIH, it is likely that the Dandy criteria need to be updated and that perhaps renaming IIH should be considered.

Utility of CT venography in monitoring stent patency in idiopathic intracranial hypertension: retrospective single-center study.

BACKGROUND: Cerebral venous sinus stenting is an established treatment for patients with idiopathic intracranial hypertension (IIH), refractory to medical management and with stenotic venous sinus on conventional cerebral venography. Currently, there are no clear guidelines on optimal noninvasive imaging modality for routine post-stenting follow-up. We investigated diagnostic yield of CT venography (CTV) for evaluation of stent patency. METHODS: We reviewed our clinical database of patients with a diagnosis of IIH, who underwent stenting of stenotic transverse or transverse/sigmoid sinus junction. Patients who had follow-up CTVs after more than 30 days were included in the final study group. All CTVs were reviewed by two readers for in-stent thrombosis, extrinsic stent compression, juxta-stent stenosis, and new contralateral venous sinus stenosis. Inter-observer agreement and association of stent patency with clinical outcomes (headache and papilledema) were assessed. RESULTS: In all 36 included patients with 38 cerebral venograms for stenting, follow-up CTVs demonstrated adequate opacifications of the venous sinuses and stents for confident evaluation for in-stent thrombosis, extrinsic stent compression, juxta-stent stenosis, and new contralateral venous sinus stenosis, with inter-observer agreement coefficient of 0.7, 1.0, 0.8, and 1.0 respectively. Association between abnormal CTV and higher rates of persistent headache and lower rates of headache improvement/resolution was statistically significant (P-value of 0.01). CONCLUSION: CTV is a reliable noninvasive imaging modality for evaluation of cerebral venous sinuses and stent patency following treatment of idiopathic intracranial hypertension with venous sinus stenting and could be used as a routine follow-up study.

Superonasal Transconjunctival Optic Nerve Sheath Decompression: A Simplified Technique for Safe and Efficient Decompression.

BACKGROUND: Severe, permanent vision loss is a feared sequela of untreated or refractory idiopathic intracranial hypertension (IIH). For patients with progressive vision loss despite maximally tolerated medical treatment, optic nerve sheath decompression (ONSD) remains a viable and effective option to protect vision. Our objective is to introduce a modified transconjunctival technique for ONSD and determine its safety, efficacy, and efficiency in patients with IIH. METHODS: We performed analyses for a retrospective case series of consecutive patients with IIH by modified dandy criteria who underwent isolated superonasal transconjunctival optic nerve sheath decompression (stOND) at single eye institute in a large academic center from January 2013 to February 2017. Sixty-six patients were identified who met these criteria with at least 6 weeks of follow-up data. Primary outcome measures were visual field mean deviation, grading of papilledema by the modified Frisen scale, and best-corrected visual acuity. Secondary outcome measures were presence of postoperative diplopia and operative time. RESULTS: One hundred thirty-two eyes of 66 patients were identified; 58 were female (88%), and 8 were male (12%). The mean age was 30 years (range 13-55) with an average lumbar puncture opening pressure of 38 cm H2O. Participants mean body mass index was 36 (range 20-59) with Grade 3 papilledema on average by the modified Frisen scale. No patients experienced operative complications, postoperative diplopia, or worse visual acuity at 1 week after surgery. Average operative time was 50 minutes (range: 25-89). The median decrease in papilledema grading was 3 grades on the Frisen scale (95% confidence interval [CI], 2-3, P < 0.0001). Snellen visual acuity changes did not meet statistical significance. The average Humphrey Visual Field mean deviation change was +1.91 (95% CI, 0.58-3.24, P = 0.0052). Despite successful bilateral decompressions, 4 patients (6.1%) progressed in their visual loss. CONCLUSIONS: The superonasal transconjunctival approach to ONSD is a safe, efficient and effective surgical treatment for patients with deteriorating visual function due to IIH. Although additional study is required to further clarify the best timing and indications for ONSD among other treatment options for refractory IIH, providers should be aware of the reduced complication rates and efficacy of the stOND technique.

Correlation Between Optic Disc Peripapillary Capillary Network and Papilledema Grading in Patients With Idiopathic Intracranial Hypertension: A Study of Optical Coherence Tomography Angiography.

BACKGROUND: The continued increase in idiopathic intracranial hypertension (IIH) prevalence has many implications for societal health care. Its potential vision-threatening consequences make ophthalmologists key players in its diagnosis and management. Newer technology such as optical coherence tomography angiography (OCT-A) enables evaluation of the branching complexity of the peripapillary capillary plexus, a region where accurate imaging via fluorescein angiography was previously limited. METHODS: A cross-sectional, observational study of 23 (46 eyes) consecutive patients with IIH. Peripapillary total vasculature was recorded using commercial OCT-A en face vessel density mapping. In addition, OCT-A blood flow slab was compared with papilledema grading. OCT-A images were analyzed using a customized image analysis protocol using ImageJ software (v1.51w) and Photoshop software (Adobe Systems, CA). SPSS software version 25 was used for statistical analysis (SPSS Inc, IBM, Chicago, IL). RESULTS: Skeletonized vessel density peripapillary capillary plexus was significantly associated with Frisen papilledema grades, OCT retinal nerve fiber layer (RNFL), and macular ganglion cell layer (GCL) thickness with a P < 0.001, P = 0.022, and P = 0.006, respectively. Every point increase in grade was correlated with a decrease of 9.1 pixels/mm2 in vessel density (R = 0.512, ß = -0.115 ± 0.029; P < 0.001). Increased papilledema was correlated with an increased retinal blood flow percentage (R = 0.300, ß = 2.114 ± 1.013; P < 0.05) and decreased choroidal blood flow (CBF) percentage (R = 0.300, ß = 2.114 ± 1.013; P < 0.05). Every point increase in grade was correlated with a decrease in CBF by 47.4%, as calculated using a linear best-fit line inclusive for all of the data points. CONCLUSIONS: OCT-A allows for effective visualization and quantification of the peripapillary retinal vasculature. Our results demonstrate a correlation between skeletonized peripapillary density and papilledema grading, OCT RNFL thickness, and GCL thickness. In addition, we show a significant negative correlation between CBF and papilledema grading. These changes provide key findings regarding the pathophysiology of optic neuropathy in papilledema and highlight the potential of OCT-A as a diagnostic tool for papilledema and a clinical marker for detecting early optic nerve damage.