Initial experience with ihtOBTURA^®: A novel EVOH-based embolic agent in the preoperative embolization of hypervascular head, neck, and spinal tumors

Abstract

Background

Preoperative embolization of hypervascular tumors facilitates safer surgical resection by reducing intraoperative bleeding and operative time. ihtOBTURA^® is a novel EVOH-based liquid embolic agent characterized by progressive post-procedural loss of radiopacity due to iodine-based contrast properties. This report presents our initial clinical experience using ihtOBTURA^® for presurgical embolization of hyper vascular tumors.

Methods

We retrospectively reviewed 15 patients (mean age 41.3 years; 9 females) undergoing 16 embolization procedures with ihtOBTURA^® between February and September 2022. Collected data included demographics, lesion pathology and location, arterial feeders, embolization technique, number of pedicles, embolic volume (ml), LEA viscosity, percentage angiographic devascularization, CT artifacts, procedural and technical complications, and surgical outcomes.

Results

Tumor types included meningiomas (n = 9), juvenile nasal angiofibromas (n = 2), carotid body tumors (n = 2), glomus jugulare tumor (n = 1), solitary fibrous tumor (n = 1), and aneurysmal bone cyst (n = 1). Complete (100%) or near-complete (>80%) devascularization was achieved in 80% of patients. The median volume of ihtOBTURA^® used was 4.3 ml (range: 1.0–13.0 ml). Mean procedure time was 90 min (range: 40–176). Surgical resection was completed in 13/14 surgical cases, with a median intraoperative blood loss of 462 ml. No major complications related to the embolization procedures were observed. Excellent penetration and diffusion of the ihtOBTURA^® into the tumor was documented through preoperative imaging and operative pathology samples. Post-embolization imaging showed reduced artifacts.

Conclusion

ihtOBTURA^® is an efficient and safe alternative embolic agent for preoperative tumor devascularization.

Introduction

Preoperative embolization is a widely accepted adjunct to surgery for hyper vascular tumors of the brain, spine, and head and neck region. These tumors—most commonly meningiomas, paragangliomas, juvenile nasopharyngeal angiofibromas, and certain metastatic lesions—pose intraoperative challenges due to their dense vascularity, increasing the risk of blood loss, prolonged operative time, and surgical complications.^1–4

Preoperative embolization reduces intraoperative blood loss, shortens surgical time, and decreases surgical morbidity and mortality. Furthermore, intraoperative hemorrhage renders the complete resection of a lesion more difficult, which increases the risk of recurrence. Embolization improves the surgical field, enables more complete resections, and is associated with improved surgical outcomes.^5–8

Embolization techniques have progressed from the use of particulate agents (e.g., polyvinyl alcohol particles, calibrated microspheres) to liquid embolic agents (LEAs). Among LEAs, non-adhesive ethylene-vinyl alcohol (EVOH)-based formulations such as Onyx and Squid have demonstrated superior vascular penetration and durable occlusion and are widely preferred in many centers.^1,28–15 However, their dependence on tantalum powder for radiopacity presents several limitations: risk of microcatheter occlusion, potential for rupture of fragile capillary beds, impaired distal diffusion in small-caliber vessels, and substantial susceptibility artifacts on CT and MRI, which may interfere with surgical planning and intraoperative navigation.

ihtOBTURA^® (IBERHOSPITEX, Spain) is a novel non-adhesive liquid embolic agent (LEA) composed of EVOH dissolved in DMSO, with an iodinated radiopaque component.^16,17 Preliminary data from the CLARIDAD trial and related studies indicate that ihtOBTURA^® achieves deep intranidal diffusion with excellent visualization and delineation of the embolized vascular architecture, no microcatheter occlusion despite prolonged injection pauses, reduced risk of vascular rupture, fewer imaging artifacts, progressive post-embolization loss of radiopacity, and favorable precipitation kinetics comparable to other EVOH-based LEAs.^16–19

The clinical implementation of ihtOBTURA^® in neurovascular applications—such as arteriovenous malformations (AVMs), dural arteriovenous fistulas (DAVFs), and hypervascular tumors—remains limited. However, previous reports have demonstrated its safety and feasibility.^16–20

In this report, we present our institutional experience with ihtOBTURA^® for the preoperative embolization of hypervascular tumors across diverse anatomical locations. We detail technical performance, procedural parameters, and surgical outcomes, emphasizing the distinct practical advantages of this novel embolic agent in clinical practice.

Materials and methods

We performed a retrospective analysis of prospectively collected consecutive patients with hyper vascular tumors who were under presurgical embolization with ihtObtura^®, between February and September 2022, at the Institute of Neurology and Neurosurgery, Havana, Cuba. To evaluate the efficacy, procedural considerations, and technical aspects of ihtOBTURA^® (IBERHOSPITEX, Spain) in the preoperative embolization of hyper vascular tumors of the head, neck, and spine.

The study was approved by the hospital's ethics committee (ethics committee of the Institute of Neurology and Neurosurgery). Informed consent was obtained from all patients before treatment, with legal representatives signing for pediatric patients.

Inclusion criteria were hyper vascular tumors of the head, neck, or spine undergoing preoperative embolization.

Data were collected on patient demographics, lesion pathology, anatomical location, arterial feeders, embolization technique (plug-and-push, pressure cooker, or direct puncture), number of pedicles embolized, volume of embolic agent used (ml) and the corresponding LEA viscosity, overall percentage of angiographic volume reduction, CT imaging artifacts, procedure-related complications, and technical complications associated with the use of LEAs—including microcatheter occlusion, difficult catheter retrieval, rupture of the tumor vascular bed, or inadvertent non-target vessel embolization—as well as surgical outcomes such as intraoperative blood loss, operative duration, extent of resection, and surgery-related complications.

Particular emphasis was placed on the technical aspects of using ihtOBTURA^®, which differ substantially from those of other commonly employed LEAs, including its extensive penetration and diffusion within the target vascular bed, absence of microcatheter occlusion despite prolonged injection pauses, reduced difficulty in catheter retrieval, lower risk of vascular and capillary bed rupture, and the longer time required for the plug-and-push technique.

Prior to treatment, all patients underwent comprehensive diagnostic cerebral angiography, complemented by superselective injections, to confirm lesion hypervascularity and delineate the angioarchitecture. The angiographic evaluation included quantitative volumetric assessment of the lesion, systematic identification of arterial feeders and draining veins, characterization of the tumor blush, and evaluation of extracranial-to-intracranial anastomoses. Pre- and post-embolization volumes of the tumor vascular bed (ml) were estimated from calibrated angiographic images using the ellipsoid formula (V = (π/6) × a × b × c), where a, b, and c represent the maximum orthogonal diameters measured in centimeters, and the volume is expressed in milliliters (ml). For each lesion, the embolization percentage was calculated as embolization Percentage = ((Vpre – Vpost)/Vpre) × 100, where Vpre corresponds to the pre-embolization volume and Vpost to the immediate post-embolization volume. This approach provides a quantitative measure of the volumetric reduction achieved by endovascular treatment.

All procedures were performed under general anesthesia with systemic anticoagulation, consisting of an initial bolus of 2000 U of heparin followed by a continuous infusion of 1000 U/h. A transfemoral approach was employed to position a 6-F guiding catheter in the external carotid artery, and selective catheterization of feeding arteries was achieved using a DMSO-compatible microcatheter (Headway Duo with Traxcess-14 guidewire [MicroVention] or Sonic 1.2F with Hybrid [Balt]), depending on the anatomical configuration. ihtOBTURA^® and DMSO were prepared and loaded into syringes without prior shaking. Embolic delivery was performed under continuous single-arm fluoroscopic and subtracted roadmap guidance (Allura FD20, Philips), and post-embolization angiography was used to assess the degree of devascularization. For carotid body tumors (CBT), the neck was prepared using standard sterile surgical technique, and an 18-gauge DMSO-compatible spinal needle was inserted percutaneously and advanced into the central portion of the tumor under fluoroscopic roadmap guidance, with meticulous care to avoid injury to the carotid arteries. Once intratumoral access was achieved and the stylet removed, the hub of the spinal needle was connected to a 20-cm DMSO-compatible Luer-lock extension tubing. An intratumoral angiogram was performed through the spinal needle to confirm proper positioning within the tumor core. The dead space was then gently flushed with DMSO prior to ihtOBTURA^® embolization under a subtracted roadmap. During embolization, trans arterial angiograms were intermittently performed to monitor the degree of tumor devascularization. A final post-embolization trans arterial angiogram was obtained to confirm complete devascularization of the target tumor bed and to ensure the absence of inadvertent embolization into the cerebral circulation. In one case of CBT, balloon protection of the internal carotid artery was employed to prevent non-target embolization. Pre- and post-procedural CT scans were obtained for all patients.

Intraoperative blood loss and surgical time were recorded in the operating room by the anesthesiologist following a standardized protocol for all surgeries, while the surgical outcomes and the extent of tumor resection were reported by the neurosurgeon responsible for the procedure and confirmed by postoperative CT scan.

Histopathological analyses of all surgical specimens (n = 14) were performed by board-certified pathologists at our institution. Tumor classification and grading were carried out in accordance with the latest edition of the World Health Organization (WHO) Classification of Tumors, ensuring standardized diagnostic criteria and pathological assessment.

Results

Sixteen embolization procedures with ihtOBTURA^® were performed in fifteen patients (9 females, 6 males; mean age: 41.3 years). Patient demographics, tumor characteristics, and procedural details are summarized in Table 1.

Table 1.

Patient demographics, tumor characteristics, and procedural details.

Case No	Age	Sex	Tumor lesion type	Blood supply	Injection technique	Embolized pedicles	Volumen (ml) before/after embolization	Occlusion (%)	Embolic agent used	Procedure time (min)	Complications (endovascular procedure)	Surgical resection/surgical blood loss
1	55	F	Spheno–orbital meningioma (WHO grade 1)	MMA; STA; ADTA	P.P	2	52/10	80%	2 ml (Obt20)	65 min	None	Total / 350 ml
2	59	M	Frontal convexity meningioma (WHO grade 1)	MMA; STA	P.P	1	99/0	100%	2.5 ml (Obt20)	120 min	None	Total / 300 ml
3	43	F	Glomus jugulare tumor	APA; OA; PAA; PMA	P.P	3	211/21	90%	10.8 ml (Obt20)	150 min	None	Radiosurgery
4	68	F	Parietal Convexity meningioma (WHO grade 2)	MMA	P.P	2	235/188	20%	5 ml (Obt20)	40 min	None	Total / 700 ml
5	33	F	Carotid body tumor	APA; OA	P.P D.P	2	50/0	100%	2 ml (Obt20)	65 min	None	Total / 80 ml
6	32	F	Temporal solitary fibrous tumor (WHO grade 2)	STA	P.P	3	305/12	96%	13 ml (Obt15)	167 min	None	Total / 200 ml
7	23	M	Juvenile nasal angiofibroma	IMA	P.C	1	55/0	100%	1 ml (Obt20)	62 min	None	Total / 150 ml
8	58	M	Frontal convexity meningioma (WHO grade 1)	MMA	P.P	1	105/14	87%	4.8 ml (Obt20)	60 min	None	Total / 400 ml
9	60	F	Frontal convexity meningioma (WHO grade 2)	MMA	P.C	1	143/114	20%	1 ml (Obt20)	120 min	None	Total/1000 ml
10	21	F	Petroclival meningioma (WHO grade 1)	MMA; STA	P.P	2	153/18	88%	1.8 ml (Obt20)	60 min	None	70%/1000 ml
11	12	M	Juvenile nasal angiofibroma	Bilateral IMA; ILT; MHT; ViA	P.P	2	61/0	100%	4.5 ml (Obt20)	176 min	None	Total/200 ml
12	72	M	Frontal convexity meningioma (WHO grade 2)	MMA	P.P P.C	2	154/123	20%	1.2 ml (Obt20)	60 min	None	Total/950 ml
13	21	F	Carotid body tumor	APA.	D.P	1	12/0	100%	5.7 ml (Obt15)	60 min	None	Total/90 ml
14	45	F	Falx cerebri meningioma (WHO grade 2)	MMA; Anterior Falx artery; Pial branches of PCA and PerCA	P.P	1	267/0	100%	7 ml (Obt15)	80 min	None	Total/350 ml
15	17	M	Right acetabulum aneurysmal bone cyst	IIA branches	P.P	3	558/0	100%	2 ml (Obt20)	67 min	None	Total/700 ml (Curettage and allograft)
	41.3 (12–72) ±19.8*	60% (F)	Intracranial – 10 Head and Neck – 4 Spinal - 1		P.P – 22 P.C – 3 D.P – 2	1.7 (1–3) ± 0.79 *	164 (12–558) ± 140 */33 (0–188) ± 59 *	79 (20–100) ± 31.7*	4.3 (1–13) ± 3.6*	90.1 (40–176) ± 44.3*	-	98% (70–100%) ± 7.8*/462 ml (90–1000) ± 328 a

^a Mean (range) ± SD (per patient); MMA: middle meningeal artery; STA: superficial temporal artery; ADTA: anterior deep temporal artery; APA: ascending pharyngeal artery; OA: occipital artery; PAA: posterior auricular artery; PMA: posterior meningeal artery; IMA: internal maxillary artery; ILT: inferolateral trunk; MHT: meningohypophyseal trunk; ViA: vidian artery; PCA: posterior cerebral artery; PerCA: pericallosal artery; IIA: internal iliac artery; P.P.: plug and push technique; D.P.: direct puncture; P.C.: arterial pressure cooker; Obt20: ihtOBTURA^® 20; Obt15: ihtOBTURA^® 15.

Tumors included spheno-orbital meningioma (n = 1), convexity meningiomas (n = 5), falx cerebri meningioma (n = 1), petroclival meningioma (n = 1), glomus jugulare tumor (n = 1), juvenile nasal angiofibroma (n = 2), carotid body tumor (n = 2), solitary fibrous tumor (n = 1), and aneurysmal bone cyst (n = 1).

A total of 25 vessels were embolized using ihtOBTURA^®. The targeted vessels included: eight branches of the middle meningeal artery, five branches of the superficial temporal artery, five branches of the internal maxillary artery, three ascending pharyngeal artery branches, three parietal branches of the hypogastric artery, and one occipital artery branch.

The number of pedicles embolized per patient ranged from 1 to 3 with a mean 1.7 ± 0.79 (mean ± SD). Injection techniques included plug-and-push (n = 22), arterial pressure cooker (n = 3), and direct puncture (n = 2).

An average of 79 (20–100) ± 31.7% (mean (range) ±SD) reduction in vascularity volume was achieved. Technical success was achieved in 80% of procedures (>80% devascularization). Representative images illustrating the results of embolization are presented in Figures 1 to 4. A complete (100%) devascularization was achieved in seven cases, and a near-complete (>80%) devascularization in five cases; in three recurrent convexity meningiomas previously surgically treated with deficient arterial supply, insufficient devascularizations (20%) were achieved.

Figure 1.

Falx cerebri meningioma. (a) Left common carotid artery and (b) left vertebral artery angiograms showing tumor feeders arising from the middle meningeal artery (MMA) and pial branches of the posterior cerebral and pericallosal arteries. (c) ihtOBTURA^® cast illustrating the extent of liquid embolic agent (LEA) penetration within the tumor vascular bed and additional feeders from a single right MMA branch embolization, with the Headway Duo microcatheter (white arrow). (d) Left common carotid artery and (e) left vertebral artery angiograms showing complete tumor devascularization. (f) Hematoxylin and eosin (H&E) stain, ×20 magnification, revealing focal necrosis in the post-embolization area.

Figure 2.

Solitary fibrous tumor. (a, b) Common carotid artery angiograms demonstrating a hypervascular lesion (circle). (c) Near-complete devascularization after embolization. (d, e) ihtOBTURA^® cast showing extensive penetration of the liquid embolic agent (LEA). (f) Hematoxylin and eosin (H&E) stain, ×20 magnification, depicting a blood vessel filled with embolic material.

Figure 3.

Carotid body tumor (CBT). (a) Right common carotid artery angiogram demonstrating a hypervascular CBT blush supplied by the ascending pharyngeal artery, with splaying of the external and internal carotid arteries. (b) Direct percutaneous puncture of the tumor using an 18-gauge needle. (c) Intralesional angiogram obtained following contrast injection through the needle. (d, e) Subtracted and unsubtracted right common carotid artery angiograms showing complete tumor devascularization. (f) Subtracted lateral projection illustrating the extensive ihtOBTURA^® cast within the tumor, with excellent delineation of the tumor capillary bed.

Figure 4.

Glomus jugulare tumor. (a–c) Right common carotid artery angiograms demonstrating a hypervascular lesion at the jugular foramen, predominantly supplied by branches of the ascending pharyngeal and occipital arteries. (d, e) Internal carotid artery angiograms obtained after embolization showing near-complete devascularization of the lesion. (f) Selective external carotid artery angiogram demonstrating complete devascularization of the tumor branches arising from the external carotid artery.

The volume of ihtOBTURA^® used ranged from 1.0 to 13.0 ml, with a median of 4.3 (1–13) ± 3.6 ml per patient. A total of 64.3 ml of embolic agent was administered, comprising 38.6 ml of ihtOBTURA^®20 and 25.7 ml of ihtOBTURA^®15. The mean endovascular procedure time was 90.1 min (range, 40–176 min) ± 44.3. No major complications, including neurological deficits or ischemic events, were observed.

Extensive penetration and diffusion of the embolic agent were documented in all cases, except for three patients with prior surgeries and severely compromised arterial feeders. No instances of microcatheter occlusion or difficulty in catheter retrieval were observed, even in the presence of significant reflux; catheter withdrawal was subjectively reported by the neurointerventionist to be easier compared with other EVOH-based LEAs. No vascular bed rupture occurred, and in several cases, deep diffusion of the embolic agent from the target vascular bed into additional arterial feeders was noted (Figure 1). Achieving the proximal plug required longer waiting times during the plug-and-push technique; however, this did not significantly prolong the overall embolization procedure due to improved diffusion efficiency.

The mean interval between endovascular and surgical intervention was 5.9 days. Surgical resection was complete in 13 patients (92.9%), with subtotal resection (>70%) in one case with an extensive petroclival meningioma. In the patient with a Glomus jugulare tumor and substantial devascularization (>90%), radiosurgery was chosen to treat the residual lesion. Estimated intraoperative blood loss ranged from 90 ml to 1000 ml (median: 462 ml) ± 328 ml, and the mean surgical time was 305 min. In the surgeon's judgment, preoperative embolization improved surgical conditions and facilitated tumor removal.

Histological analysis identified four meningothelial meningiomas (WHO grade 1), four atypical meningiomas (WHO grade 2), two carotid body paragangliomas, two juvenile nasopharyngeal angiofibromas, one solitary fibrous tumor (WHO grade 2), and one aneurysmal bone cyst.

Illustrative cases

Case 14 (Figure 1). A 45-year-old woman was diagnosed with a falx cerebri meningioma (WHO grade 2) after presenting with progressive headache. MRI demonstrated a well-circumscribed, homogeneously enhancing extra-axial mass arising from the posterior two-thirds of the falx cerebri. Preoperative angiography revealed a hypervascular tumor with arterial supply from the middle meningeal artery, the anterior falx artery, and pial branches of the posterior cerebral and pericallosal arteries. The pre-embolization tumor volume was estimated at 267 ml. Super-selective embolization was performed via a single microcatheterization of the right middle meningeal artery (MMA) using the plug-and-push technique. A total of 7 ml of ihtOBTURA^® 15 was injected with controlled reflux, achieving retrograde penetration into all identified tumor feeders, including the anterior falx artery and pial branches. Post-embolization angiography demonstrated complete devascularization of the lesion, with angiographic exclusion of all dural and pial afferents. The post-embolization tumor volume was estimated at 0 ml. The procedure was completed without complications. On the sixth day post-embolization, the patient underwent complete surgical resection of the tumor. The surgery lasted 390 min, with no intraoperative complications. The estimated blood loss was 350 ml, and no transfusion was required.

Case 6 (Figure 2). A 32-year-old woman was diagnosed with a temporal solitary fibrous tumor. The patient had previously undergone surgical resection, and follow-up imaging revealed tumor recurrence with extension into the middle cranial fossa. CT, MRI, and digital subtraction angiography (DSA) demonstrated a large, hyper vascular lesion with intense tumor blush, supplied exclusively by branches of the superficial temporal artery. The tumor volume was estimated at 305 ml prior to embolization. Preoperative embolization was performed using a super-selective plug-and-push technique, with microcatheterization of three distinct arterial feeders from the superficial temporal artery. A total of 13 ml of ihtOBTURA^® 15 was delivered, achieving 96% devascularization, with almost complete elimination of the tumor blush on post-embolization angiography. The post-embolization tumor volume was estimated at 12 ml. The endovascular procedure lasted 167 min and was well tolerated, with no complications reported. On the fourth day post-embolization, the patient underwent complete surgical resection via craniotomy. The procedure lasted 420 min and was completed without intraoperative complications. Estimated blood loss was 200 ml, and no transfusion was required. Histopathological analysis confirmed a spindle cell neoplasm with a characteristic “staghorn” vascular pattern, consistent with a solitary fibrous tumor (WHO grade 2).

Case 13 (Figure 3). A 21-year-old woman presented with a painless, pulsatile mass on the left side of the neck. Ultrasound and MRI revealed a hyper vascular lesion at the carotid bifurcation, consistent with CBT. DSA demonstrated a highly vascular mass splaying the internal and external carotid arteries, with arterial supply originating from the ascending pharyngeal artery. Under fluoroscopic guidance, direct percutaneous puncture of the tumor was performed using an 18-gauge needle. A total of 5.7 ml of ihtOBTURA^® 15 was injected using a controlled delivery technique, achieving complete devascularization with 100% occlusion of the tumor blush on final angiographic evaluation. Tumor volume decreased from 12 ml pre-embolization to 0 ml post-embolization. On the fourteenth day following embolization, the patient underwent complete surgical resection via a transcervical approach. The procedure was uneventful, with no intraoperative complications and no transfusion required. Estimated blood loss was 90 ml, and postoperative hemoglobin and hematocrit levels remained stable. Histopathological analysis confirmed a paraganglioma consistent with CBT.

Discussion

Preoperative endovascular embolization offers multiple benefits in the surgical management of hyper vascular head, neck, and spinal tumors, including reduced intraoperative blood loss, decreased transfusion requirements, improved surgical visualization, facilitation of tumor resection through necrosis and softening, minimization of brain retraction due to decreased mass effect, and prolongs time to recurrence in the case of meningioma.^1–11

Embolization allows selective occlusion of surgically inaccessible arterial feeders and helps localize displaced tumor vessels. These advantages have been supported by several studies.^2,3,5

Our initial experience with ihtOBTURA^® confirms its feasibility and safety as an LEA for the preoperative treatment of hyper vascular tumors. The technical characteristics, including non-adhesive behavior and controlled injection profile, were similar to those of Onyx and Squid, consistent with prior reports. ^{1 3–5,12}

The 80% rate of complete or near-complete (>80%) tumor devascularization observed in our cohort is consistent with published outcomes for Onyx and Squid in similar indications, which typically range from 70% to 90% depending on tumor histology, vascular supply, and embolization technique.^1–5,12,13 Of note, complete devascularization was achieved in cases with well-defined arterial pedicles, underscoring the importance of meticulous preprocedural angio architectural mapping.

Importantly, no major complications—including vessel rupture, microcatheter occlusion, microcatheter entrapment, or non-target embolization—were encountered. The absence of microcatheter occlusion despite prolonged pauses during injection is consistent with previous ihtOBTURA^® reports,^16–19 and may reflect the absence of tantalum, compound's lower viscosity, and favorable precipitation kinetics. In all cases, catheter retrieval was subjectively described as easier than with tantalum-based LEAs, a clinically relevant observation warranting further systematic evaluation.

Several distinct properties of ihtOBTURA^® were notable: Penetration and diffusion were consistently rated as excellent, with angiographic and histopathological confirmation of deep vascular bed infiltration. In several cases, the embolic column extended into secondary feeders not directly catheterized, suggesting improved diffusion and penetration consistent with observations from previous studies.^16–20 A reduction of post-embolization imaging artifacts, likely related to the iodine-based radiopacity mechanism, could facilitate imaging assessment and surgical planning. This feature represents a potential advantage in tumor resection planning compared to agents like Onyx and Squid, where beam-hardening and blooming artifacts may compromise imaging resolution in CT and MR modalities. An additional benefit is the absence of sparking during surgery, a concern occasionally reported with tantalum-based agents due to their metallic composition.

Notably, the technical success was lower in previously operated meningiomas with compromised vascular supply, highlighting the procedural challenges of embolization in recurrent or poorly vascularized lesions. This underscores the need for careful case selection and individualized strategy planning, especially in re-operations.

From a procedural perspective, longer plug formation times were observed using the plug-and-push technique, requiring patience and injection pauses. However, this did not significantly extend total procedure times due to improved distal penetration efficiency and avoidance of repetitive catheterizations. Importantly, the flexibility to alternate between plug-and-push, pressure cooker, and direct puncture approaches without technical limitation supports the agent's adaptability across tumor types and anatomical scenarios.

In our series, estimated intraoperative blood loss ranged from 90 ml to 1000 ml, with a median of 462 ml, and the mean surgical time was 305 min. According to the operating neurosurgeons, preoperative embolization improved intraoperative conditions by reducing tumor vascularity and facilitating a safer and more efficient resection. These findings are consistent with prior studies reporting reduced blood loss and enhanced surgical maneuverability following embolization of hypervascular tumors. Dean et al., in a matched cohort of 33 patients with embolized meningiomas, reported a statistically significant reduction in estimated blood loss (by 300 ml) and transfusion requirements, with a trend toward shorter operative times and hospital stay. ⁸ Oka et al. observed a mean transfusion savings of 11.7 units in skull base meningiomas smaller than 6 cm; however, this benefit was not seen in larger tumors, and operative time did not differ. ¹⁰ Gutiérrez-Baños et al. reported that presurgical embolization with EVOH was associated with a significant reduction in intraoperative blood loss and operative time. In a comparative analysis of 48 patients undergoing meningioma resection, those who received embolization exhibited markedly lower total blood loss (650 vs. 1700 ml), bleeding during the resection phase (450 vs. 1400 ml), and shorter anesthetic and surgical durations (270 vs. 372 min and 222 vs. 348 min, respectively; P < 0.01 for all comparisons). Notably, bleeding adjusted for tumor volume was significantly reduced in the embolized group (9.3 vs. 31.4 ml/cm³), highlighting the hemodynamic benefits of embolization. ¹¹

Although these results are promising, the study has several limitations. First, the sample size is small and reflects early experience from a single center. Second, while outcomes are comparable to those obtained with other LEAs, no formal control group or randomization was included. Third, histological diversity within the cohort (e.g., meningioma vs. angiofibroma vs. solitary fibrous tumor) introduces variability in embolization targets and vascular patterns that may influence generalizability. Finally, the use of the volumetric ellipsoid method represents an approximation, as its accuracy and reproducibility have not been formally validated, and therefore constitutes a major limitation of this study.

Nonetheless, this study adds to the growing body of literature supporting ihtOBTURA^® as a clinically viable and safe alternative to traditional EVOH agents, with the added benefits of reduced imaging artifacts, improved visualization of embolized tumoral capillary bed, and potentially superior penetration and diffusion, with reduced risk of vascular rupture in certain cases.

Another point to be evaluated is whether the extensive intratumoral penetration, diffusion, and complete devascularization—facilitated by the deep diffusion of ihtObtura^® into the tumor capillary bed—may be sufficient to achieve long-term control of benign tumors and reduce the need for surgical resection in selected cases and anatomical contexts. The tumor volume reduction may result not only from classical ischemic necrosis secondary to devascularization, but also from the progressive resorption of the radiopaque component of ihtObtura^®, which may further contribute to mass effect reduction. Based on available literature,^21,22 this potential paradigm shift in the management of hyper vascular benign tumors warrants further investigation, particularly in lesions located in surgically challenging regions or in patients with elevated surgical risk.

Future prospective and comparative studies are warranted to validate the potential advantages of ihtOBTURA^® and to determine its effectiveness relative to conventional embolic agents and emerging alternatives.

Conclusion

ihtOBTURA^® appears to be a safe and technically effective liquid embolic agent for the preoperative embolization of hypervascular tumors.