Long-Term Hemorrhage and Reperfusion Rates of Coiled Aneurysms: A Single-Center Experience.

Background: The endovascular approach has emerged as standard therapy for many intracranial aneurysms (IAs) to prevent hemorrhage, yet its long-term durability varies considerably. The aim of this study was to evaluate the safety and effectiveness of an initially deliberate endovascular approach regarding IA hemorrhage rates over a long-term follow-up period. Methods: This retrospective single-center study included all consecutive patients with endovascularly treated IAs who presented between January 2008 and December 2020 with a follow-up of at least 12 months. The primary endpoint was the proportion of patients with long-term IA hemorrhage rates and reperfusion. The secondary endpoint was treatment-related morbidity and mortality. Independent risk factors for IA reperfusion over the long term were analyzed using multivariate logistic regression. Results: Endovascular treatment was the therapy of choice for 333 patients with IAs, among whom 188 (57%) experienced rupture upon presentation. Complete coiling (Raymond I) was noted in 162 (49%) of the patients, with primary supportive devices being used in 51 (15%) patients. After a median (±SD) follow-up time of 34 ± 41 months (range 12-265 months), IA reperfusion was noted in 158 (47%), necessitating retreatment in 105 (32%) of the patients. Over the long term, hemorrhage was noted in four (1%) patients. Multivariate analysis revealed aneurysmal multilobarity (HR 1.8, 95%CI 1.2-2.7; p = 0.004) and a patient age of ≥50 years (HR 1.7, 95% CI 1.1-2.5, p = 0.01) as independent predictors of reperfusion over time. Intervention-related morbidity was noted in 16 (4.8%) patients, namely, thrombosis formation and contrast extravasation in 8 (2.4%) patients each, while no intervention-induced mortality was observed. Conclusion: In the long term, the hemorrhage rate in patients with IA with an initially more conservative endovascular approach is low. Therefore, a deliberate endovascular treatment approach might be justified.

Combined Microsurgical and Endovascular Intracranial Aneurysm Treatment: Interdisciplinary Experience Using a True Hybrid Approach and a Systematic Review of the Literature.

(1) Background: Most intracranial aneurysms (IAs) can be treated either with microsurgical clipping or endovascular techniques. In a few cases, simultaneous treatment utilizing both modalities in a hybrid operation room may be favorable. This study analyzes the indication and benefits of a true hybrid approach (tHA) that combines simultaneous endovascular and microsurgical procedures for treatment of IAs in one session. (2) Methods: All patients receiving a true hybrid procedure between 2010 and 2022 in our institution were included. Demographic characteristics, neurological symptoms, pre-interventional treatments, angiographic findings, and postoperative clinical and radiological outcomes were analyzed. Results are discussed in the light of a systematic literature review on reported true hybrid procedures for IA treatment. (3) Results: In total, 10 tHAs were performed. Of these, coiling and concomitant decompressive craniectomy or hematoma evacuation was performed on six occasions. In two patients, multiple IAs were treated with different modalities during the same procedure. In two patients, intraoperative conditions did not allow for complete IA clipping, and the remnant was coiled in the same session. The review of the literature revealed nine papers comprising 58 IAs treated with a tHA. (4) Conclusions: The need for a tHA for IA treatment is rare and limited to highly selective cases. In our experience, tHAs have been most valuable in an emergency setting concerning ruptured IAs. Furthermore, tHAs may also be considered in patients with multiple aneurysms in different vascular territories.

Intra-aneurysmal contrast agent stasis during intraoperative digital subtraction angiography may predict long-term occlusion after clipping.

PURPOSE: The routine use of intraoperative digital subtraction angiography (iDSA) increases detection of intracranial aneurysm (IA) remnants after microsurgical clipping. Spontaneous thrombosis of IA remnants after clipping is considered a rare phenomenon. We analyse iDSA characteristics to find predictors for IA remnant thrombosis. METHODS: IA with intraoperative detection of a remnant after clipping were identified and divided into remnants experiencing spontaneous thrombosis, and remnants with long-term patency and/or remnant growth. Angiographic features of iDSA were analysed and compared between the two groups. RESULTS: Of 37 IAs with intraoperative remnant on 3D-iDSA, five sustained a spontaneous remnant thrombosis and remained occluded in long-term follow-up. In all five cases, iDSA revealed delayed inflow and consequent stasis of the contrast agent until the late venous phase. On the other hand, in all cases with persistent long-term IA remnants (n = 32) iDSA demonstrated timely arterial contrast inflow and wash-out without stasis of intra-aneurysmal contrast agent. CONCLUSIONS: Contrast stasis in IA remnants during iDSA appears to predict long-term IA occlusion, indicating that clip correction manoeuvres or even attempted endovascular treatment of the remnant IA may be avoided in these patients.

Aneurysm healing following treatment with biodegradable embolization materials: assessment in a rat sidewall aneurysm model.

BACKGROUND: Biodegradable materials that dissolve after aneurysm healing are promising techniques in the field of neurointerventional surgery. We investigated the effects of various bioabsorable materials in combination with degradable magnesium alloy stents and evaluated aneurysm healing in a rat aneurysm model. METHODS: Saccular aneurysms were created by end-to-side anastomosis in the abdominal aorta of Wistar rats. Untreated arterial grafts were immediately transplanted (vital aneurysms) whereas aneurysms with loss of mural cells were chemically decellularized before implantation. All aneurysms were treated with biodegradable magnesium stents. The animals were assigned to vital aneurysms treated with stent alone or decellularized aneurysms treated with stent alone, detachable coil, or long-term or short-term biodegradable thread. Aneurysm healing, rated microscopically and macroscopically at follow-up days 7 and 21, was defined by both neointima formation and absence of aneurysm volume increase over time. RESULTS: Of 56 animals included, significant increases in aneurysm volume 7 days after surgery were observed in aneurysms with vital and decellularized walls treated with a stent only (P=0.043 each group). Twenty-one days after surgery an increase in aneurysm volume was observed in decellularized aneurysms treated with long- and short-term biodegradable threads (P=0.027 and P=0.028, respectively). Histological changes associated with an increase in aneurysm volume were seen for aneurysm wall inflammation, periadventitial fibrosis, and luminal thrombus. CONCLUSIONS: An increase in aneurysm volume was associated with an absence of intrasaccular embolization material (early phase) and the breakdown of intrasaccular biodegradable material over time (late phase). Thrombus remnant and aneurysm wall inflammation promote aneurysm volume increase.

Safety and functional outcome analysis of ventriculoperitoneal shunt placement for hydrocephalus within the critical phase of possible delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

Shunt-dependent hydrocephalus (HC) is a common sequela following aneurysmal subarachnoid hemorrhage (aSAH). However, there is still poor evidence regarding the optimal timing of ventriculoperitoneal shunt (VPS) placement, particularly in the context of early aSAH-associated complications such as delayed cerebral ischemia (DCI). The purpose of this study was to compare the impact of early (< 21 days after aSAH) versus late (≥ 21 days after aSAH) VPS placement on the functional clinical outcome. We retrospectively analyzed data from 82 patients with VPS placement after aSAH enrolled in our institutional database between 2011 and 2021. We compared two groups, early VPS placement (< 21 days after aSAH) versus late VPS placement (≥ 21 days after aSAH) in terms of demographics, SAH grading, radiological parameters, externalized cerebrospinal fluid diversions, DCI, VPS variables, and functional outcome. We identified 53 patients with early and 29 patients with late VPS implantation. Baseline variables, such as the modified Rankin Scale (mRS), the World Federation of Neurological Surgeons Scale, the Glasgow Coma Scale, and Fisher grade were not significantly different between the groups. Postoperatively, the mRS (p = 0.0037), the Glasgow Outcome Scale (p = 0.0037), and the extended Glasgow Outcome Scale (p = 0.0032) showed significantly better functional results in patients with early cerebrospinal fluid diversion. The rate of DCI did not differ significantly between the groups (p = 0.53). There was no difference in the rate of VPS placement associated complications (p = 0.44) or overall mortality (p = 0.39). Early shunt implantation, within 21 days after aSAH and therefore during the timeframe of possible DCI, might not be harmful in patients developing HC after aSAH.

Topographic distribution of inflammation factors in a healing aneurysm.

BACKGROUND: Healing of intracranial aneurysms following endovascular treatment relies on the organization of early thrombus into mature scar tissue and neointima formation. Activation and deactivation of the inflammation cascade plays an important role in this process. In addition to timely evolution, its topographic distribution is hypothesized to be crucial for successful aneurysm healing. METHODS: Decellularized saccular sidewall aneurysms were created in Lewis rats and coiled. At follow-up (after 3 days (n = 16); 7 days (n = 19); 21 days (n = 8)), aneurysms were harvested and assessed for healing status. In situ hybridization was performed for soluble inflammatory markers (IL6, MMP2, MMP9, TNF-α, FGF23, VEGF), and immunohistochemical analysis to visualize inflammatory cells (CD45, CD3, CD20, CD31, CD163, HLA-DR). These markers were specifically documented for five regions of interest: aneurysm neck, dome, neointima, thrombus, and adjacent vessel wall. RESULTS: Coiled aneurysms showed enhanced patterns of thrombus organization and neointima formation, whereas those without treatment demonstrated heterogeneous patterns of thrombosis, thrombus recanalization, and aneurysm growth (p = 0.02). In coiled aneurysms, inflammation markers tended to accumulate inside the thrombus and in the neointima (p < 0.001). Endothelial cells accumulated directly in the neointima (p < 0.0001), and their presence was associated with complete aneurysm healing. CONCLUSION: The presence of proinflammatory cells plays a crucial role in aneurysm remodeling after coiling. Whereas thrombus organization is hallmarked by a pronounced intra-thrombotic inflammatory reaction, neointima maturation is characterized by direct invasion of endothelial cells. Knowledge concerning topographic distribution of regenerative inflammatory processes may pave the way for future treatment modalities which enhance aneurysm healing after endovascular therapy.

The modified occipital condyle screw: A quantitative anatomic study investigating the feasibility of a novel instrumented fixation technique for craniocervical fusion.

Study Design: Prospective human anatomical study. Objective: Occipitocervical fusion with occipital plate or condyle screws has shown higher failure rates in those with skeletal dysplasia. The modified occipital condyle screw connects the occipital condyle to the pars basilaris of the occipital bone that may achieve fortified bony purchase and serve as a more rigid fixation point. We evaluate anatomical feasibility of a novel cranial fixation technique designed to decrease risk of pseudarthrosis. Materials and Methods: Occipital condyles were analyzed morphologically using multiplanar three-dimensional reconstructed, ultra-thin section computed tomography. The following parameters were obtained: occipital condyle length, maximal cross section, location of hypoglossal canal, axial and sagittal orientation of the long axis, occipital condyle pedicle (OCP) diameter, maximal length of OCP screw, and entry point. Results: Forty patients with total of 80 occipital condyles were analyzed and the following measurements were obtained: occipital condyle length 24.1 mm (20.5-27.7, standard deviation [SD]: 2.2); condyle maximum axial cross-section 12.6 mm (9-15.8, SD: 1.9); length of OCP screw 38.9 mm (29.3-44, SD: 5.7); diameter of OCP 3.4 mm (3.2-3.6, SD: 0.2); clearance below hypoglossal canal 4.5 mm (3.4-7, SD: 1.1); and distance of screw entry point from condylar foramen 2 mm (range 0-4, SD 1.6). Conclusion: The modified occipital condyle screw connects the condyle with the clivus through the pars basilaris and represents a safe and technically feasible approach to achieve craniocervical fusion in skeletally mature individuals. This cephalad anchor point serves as an alternate fixation point of the occipitocervical junction with increased strength of construct and decreased risk of hardware failure or pseudarthrosis given cortical bone purchase and longer screw instrumentation.

A Contemporary Clinico-Anatomical Guide to Craniovertebral Junction Surgery.

Background Surgical treatment of ventral and ventrolateral lesions of the craniocervical junction are among the most challenging neurosurgical pathologies to treat. Three surgical techniques, the far lateral approach (and its variations), the anterolateral approach, and the endoscopic far medial approach can be used to approach and resect lesions in this area. Objective The aim of the study is to examine the surgical anatomy of three skull base approaches to the craniocervical junction and review surgical cases to better understand the indications and possible complications for each of these approaches. Methods Cadaveric dissections with standard microsurgical and endoscopic instruments were performed for each of the three surgical approaches, and key steps and surgically relevant anatomy were documented. Six patients with appropriate pre-, post-, and intraoperative imaging and video documentation are presented and discussed accordingly. Results Based on our institutional experience, all three approaches can be utilized to safely and effectively approach a wide variety of neoplastic and vascular pathology. Unique anatomical characteristics, lesion morphology and size, and tumor biology should all be considered when determining the optimal approach. Conclusion Preoperative assessment of surgical corridors with 3D illustrations helps to define the best surgical corridor. 360 degree knowledge of the anatomy of craniovertebral junction allows safe surgical approach and treatment of ventral and ventrolateral located lesions using one of the three approaches.

Anatomical Variations of the Common Carotid Arteries and Neck Structures of the New Zealand White Rabbit and Their Implications for the Development of Preclinical Extracranial Aneurysm Models.

BACKGROUND: Rabbit models involving neck arteries are of growing importance for the development of preclinical aneurysm models. An optimal understanding of the anatomy is primordial to allow the conception of models while minimizing mortality and morbidity. The aim of this study is to give reliable anatomical landmarks to allow a standardized approach to the neck vessels. METHODS: We performed a necropsy on nine specimens from ongoing experimental studies. We measured the distance between the origins of the right and left common carotid artery (rCCA/lCCA) and between the rCCA and the manubrium sterni (MS). The structures at risk were described. RESULTS: Female New Zealand White rabbits (NZWR) weighing 3.7 ± 0.3 kg and aged 25 ± 5 weeks were included. The rCCA origin was located 9.6 ± 1.2 mm laterally and 10.1 ± 3.3 mm caudally to the MS. In all specimens, the lCCA originated from the aortic arch, together with the brachiocephalic trunk (BCT), and 6.2 ± 3.1 mm proximally to the rCCA origin. The external and internal jugular veins, trachea and laryngeal nerve were the main structures at risk. CONCLUSIONS: The data help to localize both CCAs and their origin to guide surgical approaches with the manubrium sterni as a main landmark. Special attention has to be paid to the trachea, jugular veins and laryngeal nerves.

Cerebral Aneurysm and Interleukin-6: a Key Player in Aneurysm Generation and Rupture or Just One of the Multiple Factors?

Intracranial aneurysm (IA) rupture is a common cause of subarachnoid hemorrhage (SAH) with high mortality and morbidity. Inflammatory interleukins (IL), such as IL-6, play an important role in the occurrence and rupture of IA causing SAH. With this review we aim to elucidate the specific role of IL-6 in aneurysm formation and rupture in preclinical and clinical studies. IL-6 is a novel cytokine in that it has pro-inflammatory and anti-inflammatory signaling pathways. In preclinical and clinical studies of IA formation, elevated and reduced levels of IL-6 are reported. Poor post-rupture prognosis and increased rupture risk, however, are associated with higher levels of IL-6. By better understanding the relationships between IL-6 and IA formation and rupture, IL-6 may serve as a biomarker in high-risk populations. Furthermore, by better understanding the IL-6 signaling mechanisms in IA formation and rupture, IL-6 may optimize surveillance and treatment strategies. This review examines the association between IL-6 and IA, while also suggesting future research directions.

Growing Fat Tissue After Grafting for Dural Sealing.

We report on a young patient with a growing retroauricular benign fat tissue tumor after juvenile fat grafting for dural sealing of a placed ventriculoperitoneal shunt. The clinical images indicate fat tissue rather than a cerebrospinal fluid leak due to potential shunt malfunction suspected on plain radiography. Human adipose tissue is a source of stem cells that can replicate rather than undergoing necrosis, in particular when transplanted during development.

Incidence and Outcome of Peri-interventional Vasospasm During Endovascular or Microsurgical Treatment of Unruptured Intracranial Aneurysms.

BACKGROUND: Peri-interventional vasospasm (PIVS) is associated with high risk of delayed cerebral vasospasm (DCVS), delayed cerebral ischemia, and poor outcome after aneurysmal subarachnoid hemorrhage. However, the incidence rate associated with treatment of unruptured intracranial aneurysm (UIA) remains unclear. OBJECTIVE: To define the incidence and clinical significance of PIVS in UIA repair based on intraoperative/peri-interventional digital subtraction angiography. METHODS: A consecutive series of 205 patients who underwent UIA treatment by means of microsurgical clipping (n = 109) or endovascular coil embolization (n = 96) was assessed for the occurrence of PIVS. In all cases, PIVS was detected, measured, and classified using intraoperative/peri-interventional digital subtraction angiography. Severity of PIVS, association of PIVS with the development of DCVS, and neurological outcome were analyzed. RESULTS: Intraoperative PIVS was present in n = 14/109 (13%) patients with microsurgical clipping. Of these, caliber irregularities were mild (n = 10), moderate (n = 3), and severe (n = 1). In endovascularly treated patients, 6/96 (6%) developed PIVS, which were either mild (n = 3) or moderate (n = 3). Management in all cases included immediate intensive blood pressure management and application of topical papaverine or intra-arterial nimodipine immediately on detection of PIVS. No patient developed DCVS or lasting neurological deficits attributable to PIVS. CONCLUSION: This series revealed a relatively high overall incidence of PIVS (10%). However, no association of PIVS with the development of DCVS or poor outcome was found. In contrast to ruptured intracranial aneurysms, PIVS in unruptured intracranial aneurysms-if immediately and adequately addressed-seems to be benign and without sequelae for patient's functional outcome.

Risk of intracranial aneurysm recurrence after microsurgical clipping based on 3D digital subtraction angiography.

OBJECTIVE: Current knowledge of recurrence rates after intracranial aneurysm (IA) surgery relies on 2D digital subtraction angiography (DSA), which fails to detect more than 75% of small aneurysm remnants. Accordingly, the discrimination between recurrence and growth of a remnant remains challenging, and actual assessment of recurrence risk of clipped IAs could be inaccurate. The authors report, for the first time, 3D-DSA-based long-term durability and risk factor data of IA recurrence and remnant growth after microsurgical clipping. METHODS: Prospectively collected data for 305 patients, with a total of 329 clipped IAs that underwent baseline 3D-DSA, were evaluated. The incidence of recurrent IA was described by Kaplan-Meier curves. Risk factors for IA recurrence were analyzed by multivariable Cox proportional hazards and logistic regression models. RESULTS: The overall observed proportion of IA recurrence after clipping was 2.7% (9 of 329 IAs) at a mean follow-up of 46 months (0.7% per year). While completely obliterated IAs did not recur during follow-up, incompletely clipped aneurysms (76 of 329) demonstrated remnant growth in 11.8% (3.4% per year). Young age and large initial IA size significantly increased the risk of IA recurrence. CONCLUSIONS: The findings support those in previous studies that hypothesized that completely clipped IAs have an extremely low risk of recurrence. Conversely, the results highlight the significant risk posed by incompletely clipped IAs. Young patients with initial large IAs and incomplete obliteration have an especially high risk for IA recurrence and therefore should be monitored more closely.

Systemic Risk Factors for Adult Spinal Deformity (ASD): A Retrospective Analysis of 48 Patients.

INTRODUCTION: Adult spinal deformity (ASD) results in significant patient morbidity and burden to quality of life. The degree to which systemic risk factors and comorbidities that contribute to ASD affect specific spinopelvic parameters is not well-documented. We determine the extent to which preoperative risk factors may contribute to spinopelvic parameters associated with ASD. METHODS: Retrospective single-center study of 48 patients with ASD. Analysis of variance (ANOVA) linear regression analysis was performed to evaluate correlation between systemic comorbidities (obesity, arterial hypertension (HTN), hyperlipidemia (HLD), cardiomyopathy, diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD), and asthma) and the following radiographic parameters: pelvic incidence (PI), lumbar lordosis (LL), C7 sagittal vertical axis (C7SVA), and the T10-L2 sagittal cobb angle. RESULTS: A total of 48 patients were included with mean C7SVA of 79.6 mm (SD: 63, range: 43-254), mean LL of 32.9° (SD: 15.9, range: -14 to 78), T10-L2 sagittal cobb angle of 3° (SD: 12.7, range: -24 to 30), and PI was 49° (SD: 10.7, range: 21 to 77). Only DM correlated with sagittal imbalance with high C7SVA and PI-LL mismatch. The beta coefficient for DM and preoperative C7SVA was 0.49, t=3.16, p=0.003, preoperative PI-LL mismatch standardized beta coefficient was -0.4, t=-2.38, p=0.022, and preoperative T10-L2 sagittal cobb standard beta coefficient was -0.07, t=-0.46, p=0.645. No significant correlations were found for asthma, COPD, HTN, HLD, or cardiomyopathy. CONCLUSIONS: Diagnosis of DM was found to correlate with pathologic C7SVA and significant PI-LL mismatch associated with ASD. HTN, HLD, cardiomyopathy, obesity, and pulmonary disease did not correlate with radiographic findings of sagittal imbalance.

Restoring Segmental Spinal Alignment in Mini-Open Lateral Spinal Deformity Surgery-Determiners of Radiographic Outcome.

OBJECTIVE: Both under- and overcorrection are risk factors for junctional failure after deformity correction. This study investigates which factors determine the segmental radiographic outcome in mini-open lateral deformity surgery. METHODS: A single-center operative database was searched for patients undergoing multilevel mini-open lateral corrective surgery of degenerative spinal deformities. Preoperative and postoperative whole spine x-rays and computed tomography scans were compared for change in global and segmental alignment parameters. Linear regression analyses were performed to study the impact of surgical level, preoperative segmental sagittal Cobb angle, presence of bridging osteophytes, disc height, ankylosis of facet joints, and implantation site of the interbody device on postoperative increase in segmental lordosis, foraminal height, and foraminal width. RESULTS: A total of 49 patients were identified with a mean age of 68.7 years. At a mean, 4.2 segments were fused using a lateral approach, while the posterior stage comprised either minimally invasive surgery or open instrumentation. Upper instrumented vertebra was L2 (range T4-L3), and lower instrumented vertebra was L5 (range L4-pelvis) in most cases. Mean radiographic values pre- and postoperatively were as follows: C7 sagittal vertical axis +79.6 mm, +60 mm; lumbar lordosis 32.9°, 41.6°; pelvic tilt 21.1°, 21.8°; global coronal Cobb 16.3°, 10.8°; increase in segmental sagittal Cobb angle was significantly and inversely correlated with preoperative sagittal Cobb and positively correlated with preoperative coronal Cobb angle. No other variable showed significant correlations. Preoperative foraminal width and height showed significant and inverse correlation with change in postoperative foraminal width and height. CONCLUSION: Segmental sagittal correction is significantly influenced by preoperative loss of lordosis and coronal Cobb angle. Neither presence of osteophytes nor ankylosed facet joints, disc height, or implantation site of the interbody device had an influence on sagittal alignment goals. Only preoperative foraminal dimensions impact inversely the degree of foraminal decompression; no other factor investigated showed significant impact. CLINICAL RELEVANCE: Only preoperative lordosis and coronal Cobb angle influence sagittal correction.

Using a Cell-Tracer Injection to Investigate the Origin of Neointima-Forming Cells in a Rat Saccular Side Wall Model.

Microsurgical clipping creates a subsequent barrier of blood flow into intracranial aneurysms, whereas endovascular treatment relies on neointima and thrombus formation. The source of endothelial cells covering the endoluminal layer of the neointima remains unclear. Therefore, the aim of the present study was to investigate the origin of neointima-forming cells after cell-tracer injection in the already well-established Helsinki rat microsurgical sidewall aneurysm model. Sidewall aneurysms were created by suturing decellularized or vital arterial pouches end-to-side to the aorta in male Lewis rats. Before arteriotomy with aneurysm suture, a cell-tracer injection containing CM-Dil dye was performed into the clamped aorta to label endothelial cells in the adjacent vessel and track their proliferation during follow-up (FU). Treatment followed by coiling (n = 16) or stenting (n = 15). At FU (7 days or 21 days), all rats underwent fluorescence angiography, followed by aneurysm harvesting and macroscopic and histological evaluation with immunohistological cell counts for specific regions of interest. None of the 31 aneurysms had ruptured upon follow-up. Four animals died prematurely. Macroscopically residual perfusion was observed in 75.0% coiled and 7.0% of stented rats. The amount of cell-tracer-positive cells was significantly elevated in decellularized stented compared to coiled aneurysms with respect to thrombus on day 7 (p = 0.01) and neointima on day 21 (p = 0.04). No significant differences were found in thrombus or neointima in vital aneurysms. These findings confirm worse healing patterns in coiled compared to stented aneurysms. Neointima formation seems particularly dependent on the parent artery in decellularized aneurysms, whereas it is supported by the recruitment from aneurysm wall cells in vital cell-rich walls. In terms of translation, stent treatment might be more appropriate for highly degenerated aneurysms, whereas coiling alone might be adequate for aneurysms with mostly healthy vessel walls.

Interrater and intrarater agreement superior for three-dimensional digital subtraction angiography (3D-DSA) over 2D-DSA classification for detecting remnants after intracranial aneurysm clipping, a GRRAS Reliability and Agreement Study.

BACKGROUND: Growing evidence suggests that three-dimensional digital subtraction angiography (3D-DSA) is superior to 2D-DSA in detection of intracranial aneurysm (IA) remnants after clipping. With a simple, practical quantitative scale proposed to measure maximal remnant dimension on 3D-DSA, this study provides a rigorous interrater and intrarater reliability and agreement study comparing this newly established scale with a commonly used (Sindou) 2D-DSA scale. METHOD: Records of 43 patients with clipped IAs harboring various sized remnants who underwent 2D- and 3D-DSA between 2012 and 2018 were evaluated. Using the 2D and 3D scales, six raters scored these remnants and repeated the scoring task 8 weeks later. Interrater and intrarater agreement for both grading schemes were calculated using kappa (κ) statistics. RESULTS: Interrater agreement was highly significant, yielding κ-values at 95% CI (p = 0.000) of 0.225 for the first [0.185; 0.265] and 0.368 s [0.328; 0.408] time points for 2D-DSA and values of 0.700 for the first [0.654; 0.745] and 0.776 s [0.729; 0.822] time points for 3D-DSA. Intrarater agreement demonstrated κ-values between 0.139 and 0.512 for 2D-DSA and between 0.487 and 0.813 for 3D-DSA scores. CONCLUSION: Interrater and intrarater agreement was minimal or weak for 2D-DSA scores, but strong for 3D-DSA scores. We propose that baseline 3D-DSA characterization may prove more reliable when categorizing clipped IA remnants for purposes of risk stratification and lifelong follow-up.