Endovascular Treatment of Chronic Subdural Hematomas through Embolization: A Pilot Study with a Non-Adhesive Liquid Embolic Agent of Minimal Viscosity (Squid)

Abstract

Objective: Endovascular embolization using non-adhesive agents (e.g., ethylene vinyl alcohol copolymer with suspended micronized tantalum dissolved in dimethyl sulfoxide; Squid, Balt Extrusion) is an established treatment of brain arteriovenous malformations, dural arteriovenous fistulas, and hypervascular neoplasms. Middle meningeal artery (MMA) embolization is a relatively new concept for treating chronic subdural hematomas (CSDH). This study aimed to evaluate the safety and effectiveness of the use of Squid in the endovascular treatment of CSDH. Methods: Embolization was offered to patients with CSDH with minimal or moderate neurological deficits and patients who had previously undergone open surgery to evacuate their CSDH without a significant effect. Distal catheterization of the MMA was followed by embolization of the hematoma capsule with Squid 12 or Squid 18. Safety endpoints were ischemic or hemorrhagic stroke and any other adverse event of the endovascular procedure. Efficacy endpoints were the feasibility of the intended procedure and a ≥ 50% reduction of the maximum depth of the CSDH confirmed by follow-up computed tomography (CT) after >3 months. Results: Between November 2019 and July 2021, 10 patients (3 female and 7 male, age range 42–89 years) were enrolled. Five patients had bilateral hematomas, and five patients had previously been operated on with no significant effect and recurrent hematoma formation. The attempted embolization was technically possible in all patients. No technical or clinical complication was encountered. During a post-procedural follow-up (median 90 days), 10 patients improved clinically. A complete resolution of the CSDH was observed in 10 patients. The clinical condition of all enrolled patients during the so-far last contact was rated mRS 0 or 1. Conclusion: A distal catheterization of the MMA for the endovascular embolization of CSDH with Squid allowed for the devascularization of the MMA and the dependent vessels of the hematoma capsule. This procedure resulted in a partial or complete resolution of the CSDH. Procedural complications were not encountered.

Safety and radiologic clearance of chronic subdural hematoma after endovascular embolization using SQUID 18 in patients older than 80 years

“…[2,10] Petrov et al published a recent case series of cSDH treated with MMA embolization, in a younger cohort (median age 66), using SQUID 12/18 and reported good clinical and radiological results, with total reabsorption of the hematoma at 90-day follow-up. [12] The study has limitations: The small number of patients and the observational nature of our design limits more robust statistical associations. Because MMA embolizations were done in a specialized endovascular center, an inherent selection bias is present in the study.…”

Angiogenetic Factors in Chronic Subdural Hematoma Development

“…The case series was designed to study the angiogenesis factors in chronic subdural hematoma development. This article presents the second case series (the first series was published in 2021 [ 3 , 40 ]) based on the sole use of Squid (Balt Extrusion) for middle meningeal arterial (MMA) embolization as a treatment option for CSHD. The choice of Squid rather than Onyx (Medtronic) was due to the availability of this low-viscosity option [ 41 ], which allows for a deeper penetration of the embolizing agent into the vessels feeding the CSDH capsule [ 3 , 40 ].…”

“…This article presents the second case series (the first series was published in 2021 [ 3 , 40 ]) based on the sole use of Squid (Balt Extrusion) for middle meningeal arterial (MMA) embolization as a treatment option for CSHD. The choice of Squid rather than Onyx (Medtronic) was due to the availability of this low-viscosity option [ 41 ], which allows for a deeper penetration of the embolizing agent into the vessels feeding the CSDH capsule [ 3 , 40 ]. In all the patients, we determined the concentrations of angiogenesis factors in the peripheral venous blood and in the MMA (arterial blood).…”

“…The volume of the CSDH was determined by manually measuring the specific volumes, defining the area of interest using OsiriX software (Osirix for Mac, version 11.0) on a pre-embolization of NCCT [ 3 ]. In cases where the hematoma was located bilaterally, the hematoma volumes were summed and a total hematoma volume was obtained.…”

“…Generally, the etiology of CSDH has been multifactorial, and it has never been caused by trauma alone [ 3 ]. R. Virchow, in 1857, hypothesized that organized exudate accumulates in the subdural space due to a generalized inflammatory process based on his pathoanatomical studies [ 4 , 5 , 6 ].…”