Abstract

Methods

Results

A total of 46,065 patients with IIH were identified, of whom 7,545 (16.4%) received surgical treatment. There were no in-hospital mortalities or intracranial hemorrhages. Patient characteristics differed significantly among treatment modalities (Table 1). Hospital characteristics are detailed in eTable 2 (links.lww.com/WNL/C716), and patient income and insurance information are detailed in eTable 3 (links.lww.com/WNL/C717). From 2016 to 2020, the number of IIH-related admissions did not significantly change over time (9,610–8,385, p = 0.11) nor did the number of surgical IIH treatments (1,580–1,405, p = 0.47). In the same period, the number of VSS procedures increased 80% (150 procedures in 2016 to 270 procedures in 2020, p < 0.001; Table 2, Figure 1). Concurrently, the number of CSF shunt insertions and ONSF decreased 19% and 54%, respectively (p < 0.001 for both; Table 2, Figure 1). In 2020, VSS accounted for 19.2% of all surgical IIH treatments nationwide.

Table 1

Patient Characteristics

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Table 2

Temporal Trends of Surgical IIH Procedures From 2016 to 2020

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Figure

Temporal Trends of Surgical IIH Treatments From 2016 to 2020

(A) Percentage of shunt, VSS, and ONSF among all surgical IIH procedures over time; p values derived from χ² analysis. (B) Percentage change of number of procedures from 2016 to 2020; p values derived from comparison number of each procedure as a proportion of total procedures between 2016 and 2020 using the Fisher exact test. IIH = idiopathic intracranial hypertension; ONSF = optic nerve sheath fenestration; VSS = venous sinus stenting.

Over the study period, the number of VSS procedures performed at large urban academic medical centers increased 72%, and the proportion of surgical IIH treatments that were VSS increased from 12.3% to 21.9% (p < 0.001; Table 2). Similarly, the number of VSS procedures performed at smaller academic medical centers and community hospitals increased 120%, and the proportion of surgical IIH treatments that were VSS increased from 4.4% to 12.9%, a near 3-fold increase (p < 0.001; Table 2). Temporal trends of CSF shunting stratified by hospital type are also summarized in Table 2.

Discussion

In this cross-sectional study of 46,065 patients with IIH hospitalized in the United States, we show that VSS procedures increased 80% over the 5-year study period, roughly accounting for 1 in 5 surgical IIH treatments in 2020. There were concurrent decreases in the number of CSF shunts and ONSF procedures, suggesting that the practice patterns for surgical IIH treatment nationwide are rapidly evolving.

The growth of VSS procedures may have been driven by multiple factors. First, increasing number of procedures could reflect increasing incidence of IIH. Second, VSS is minimally invasive and generally considered safe, with low rates of complications.^6,7 Furthermore, the neurointerventional workforce has grown considerably in recent years,¹¹ and increased utilization of magnetic resonance and computed tomography venogram studies may have led to increased detection of cerebral venous sinus stenosis. Of importance, CSF shunts and ONSF numbers have significantly declined, suggesting that practitioners may be relatively favoring VSS instead, which may be driven by its superior safety profile⁶ and patient acceptance due to its minimally invasive nature. While it is presently unclear whether VSS procedures will continue to grow, our results show increasing VSS numbers across all hospital subtypes, particularly in smaller academic medical centers and community hospitals. This trend is likely to continue because the procedure is becoming available widely in the United States and the devices continue to improve.

While past studies have demonstrated VSS's short-term outcomes,^6,7 data on long-term comparative efficacy and safety with other treatments are sparse. Uncertainty surrounding the pathophysiologic role of venous sinus stenosis in IIH also remains, particularly regarding whether it is a cause or an effect of severe IIH.⁸ Prospective clinical trials are urgently needed to investigate the efficacy and safety of VSS compared with medical therapy and/or other surgical options. However, patient recruitment of clinical trials for surgical IIH treatments (e.g., the SIGHT trial¹²) has been difficult, which may have been driven by both the proven effectiveness of medical therapy¹³ and the high risks of CSF shunting and ONSF.^6,14,15 It is unclear whether VSS's superior safety profile could overcome challenges in recruitment. At a minimum, initiation of a nationwide prospective registry of VSS patients that includes pretreatment and posttreatment neuro-ophthalmological assessments may be helpful in shedding light on the long-term safety and effectiveness of VSS.

Our study has several limitations. First, because the identification of diseases using recorded ICD-10 codes can be inaccurate, the reporting rates of comorbidities may not always reflect the presence/absence of each condition and may instead reflect disease severity. Second, the NIS captures only hospital admissions, and IIH is mainly managed on an outpatient basis. However, CSF shunting, VSS, and ONSF procedures generally require hospital stays, so our estimations of national procedure numbers are likely accurate. Third, the NIS provides only encounter-level data, and we were not able to assess the longitudinal outcomes of patients with IIH treated with VSS. Finally, our findings of increasing VSS procedures were restricted to the United States, and external validity is unclear.

In conclusion, in this cross-sectional study of 46,065 patients with IIH, we found that VSS procedures are rapidly increasing in the United States. These findings highlight the urgency of randomized controlled trials to investigate the comparative effectiveness and safety of VSS compared with standard medical treatments.

Appendix. Authors

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References