One-Point Technique in Brainstem Cavernous Malformation Surgery: Evaluation of Approaches and Outcomes From a Different Perspective.

BACKGROUND AND OBJECTIVES: Brainstem cavernous malformations (BCMs) are a distinct clinical entity that carry a high risk of patient morbidity because of location and risk of hemorrhage. Surgical management of these lesions requires intimate knowledge of surgical anatomy and skull base approaches. This article is intended to highlight a modern approach for the treatment of BCMs, with an emphasis on the use of the one-point technique to guide resection. METHODS: We describe a case series of BCMs treated through a variety of skull base approaches, describing our decision-making strategy. We review the concept of the one-point technique focusing on the safest access to the malformation through 2 representative cases and also perform a retrospective review of 32 consecutive patients who underwent BCM resection to present outcomes and the comparison of two-point vs one-point techniques. RESULTS: Consecutive series of 32 patients in whom the one-point technique was used is presented. In 8 patients (25%), the traditional two-point technique would suggest a different trajectory than the one-point technique. Postoperative MRI confirmed complete resection in 30 patients (95%), and 29 patients (91%) had modified Rankin Scale (0-2) at follow-up. All patients in whom the one-point technique guided a different trajectory had gross total removal of the cavernous malformation, with one patient having long-term new neurological impairment from the surgery. There were no mortalities. CONCLUSION: Despite surgical advances in recent decades and more widespread understanding of surgical anatomy and safe entry zones, surgical resection of BCMs remains a formidable challenge. While not necessarily the shortest access, the one-point technique offers a safe approach considering all the different modalities in our armamentarium and can be used as part of a strategy to determine the optimal approach to resect BCMs.

Anatomical determinants of occipitocervical fusion in skull base chordoma resection: a systematic review of the literature with illustrative cases.

OBJECTIVE: Skull base chordomas are rare, locally osseo-destructive lesions that present unique surgical challenges due to their involvement of critical neurovascular and bony structures at the craniovertebral junction (CVJ). Radical cytoreductive surgery improves survival but also carries significant morbidity, including the potential for occipitocervical (OC) destabilization requiring instrumented fusion. The published experience on OC fusion after CVJ chordoma resection is limited, and the anatomical predictors of OC instability in this context remain unclear. METHODS: PubMed and Embase were systematically searched according to the PRISMA guidelines for studies describing skull base chordoma resection and OC fusion. The search strategy was predefined in the authors' PROSPERO protocol (CRD42024496158). RESULTS: The systematic review identified 11 surgical case series describing 209 skull base chordoma patients and 116 (55.5%) who underwent OC instrumented fusion. Most patients underwent lateral approaches (n = 82) for chordoma resection, followed by midline (n = 48) and combined (n = 6) approaches. OC fusion was most often performed as a second-stage procedure (n = 53), followed by single-stage resection and fusion (n = 38). The degree of occipital condyle resection associated with OC fusion was described in 9 studies: total unilateral condylectomy reliably predicted OC fusion regardless of surgical approach. After lateral transcranial approaches, 4 studies cited at least 50%-70% unilateral condylectomy as necessitating OC fusion. After midline approaches-most frequently the endoscopic endonasal approach (EEA)-at least 75% unilateral condylectomy (or 50% bilateral condylectomy) led to OC fusion. Additionally, resection of the medial atlantoaxial joint elements (the C1 anterior arch and tip of the dens), usually via EEA, reliably necessitated OC fusion. Two illustrative cases are subsequently presented, further exemplifying how the extent of CVJ bony elements removed via EEA to achieve complete chordoma resection predicts the need for OC fusion. CONCLUSIONS: Unilateral total condylectomy, 50% bilateral condylectomy, and resection of the medial atlantoaxial joint elements were the most frequently described independent predictors of OC fusion in skull base chordoma resection. Additionally, consistent with the occipital condyle harboring a significantly thicker joint capsule at its posterolateral aspect, an anterior midline approach seems to tolerate a greater degree of condylar resection (75%) than a lateral transcranial approach (50%-70%) prior to generating OC instability.

The role of surgical disconnection for posterior fossa pial arteriovenous fistulas and dural fistulas with pial supply: an illustrative case series.

BACKGROUND: Pial arteriovenous fistulas (pAVFs) are rare vascular malformations characterized by high-flow arteriovenous shunting involving a cortical arterial supply directly connecting to venous drainage without an intermediate nidus. Dural arteriovenous fistulas (dAVFs) can infrequently involve additional pial feeders which can introduce higher flow shunting and increase the associated treatment risk. In the posterior fossa, arteriovenous fistula (AVF) angioarchitecture tends to be particularly complex, involving either multiple arterial feeders-sometimes from both dural and pial origins-or small caliber vessels that are difficult to catheterize and tend to be intimately involved with functionally critical brainstem or upper cervical cord structures. Given their rarity, published experience on microsurgical or endovascular treatment strategies for posterior fossa pAVFs and dAVFs with pial supply remains limited. METHODS: Retrospective chart review from 2019-2023 at a high-volume center identified six adult patients with posterior fossa pAVFs that were unable to be fully treated endovascularly and required microsurgical disconnection. These cases are individually presented with a technical emphasis and supported by comprehensive angiographic and intraoperative images. RESULTS: One vermian (Case 1), three cerebellopontine angle (Cases 2-4) and two craniovertebral junction (Cases 5-6) posterior fossa pAVFs or dAVFs with pial supply are presented. Three cases involved mixed dural and pial arterial supply (Cases 1, 4, and 6), and one case involved a concomitant microAVM (Case 2). Endovascular embolization was attempted in four cases (Cases 1-4): The small caliber and tortuosity of the main arterial feeder prevented catheterization in two cases (Cases 1 and 3). Partial embolization was achieved in Cases 2 and 4. In Cases 5 and 6, involvement of the lateral spinal artery or anterior spinal artery created a prohibitive risk for endovascular embolization, and surgical clip ligation was pursued as primary management. In all cases, microsurgical disconnection resulted in complete fistula obliteration without evidence of recurrence on follow-up imaging (mean follow-up 27.1 months). Two patients experienced persistent post-treatment sensory deficits without significant functional limitation. CONCLUSIONS: This illustrative case series highlights the technical difficulties and anatomical limitations of endovascular management for posterior fossa pAVFs and dAVFs with pial supply and emphasizes the relative safety and utility of microsurgical disconnection in this context. A combined approach involving partial preoperative embolization-when the angioarchitecture is permissive-can potentially decrease surgical morbidity. Larger studies are warranted to better define the role for multimodal intervention and to assess associated long-term AVF obliteration rates in the setting of pial arterial involvement.

Impact of Cerebral Revascularization on Pial Collateral Flow in Patients With Unilateral Moyamoya Disease Using Quantitative Magnetic Resonance Angiography.

BACKGROUND AND OBJECTIVES: Moyamoya disease (MMD) is a chronic steno-occlusive disease of the intracranial circulation that depends on neoangiogenesis of collateral vessels to maintain cerebral perfusion and is primarily managed with cerebral revascularization surgery. A quantitative assessment of preoperative and postoperative collateral flow using quantitative magnetic resonance angiography with noninvasive optimal vessel analysis (NOVA) was used to illustrate the impact of revascularization on cerebral flow distribution. METHODS: A retrospective review of patients with unilateral MMD who underwent direct, indirect, or combined direct/indirect cerebral revascularization surgery was conducted between 2011 and 2020. Using NOVA, flow was measured at the anterior cerebral artery (ACA), ACA distal to the anterior communicating artery (A2), middle cerebral artery (MCA), posterior cerebral artery (PCA), and PCA distal to the posterior communicating artery (P2). Pial flow (A2 + P2) and collateral flow (ipsilateral [A2 + P2])-(contralateral [A2 + P2]) were measured and compared before and after revascularization surgery. Total hemispheric flow (MCA + A2 + P2) with the addition of the bypass graft flow postoperatively was likewise measured. RESULTS: Thirty-four patients with unilateral MMD underwent cerebral revascularization. Median collateral flow significantly decreased from 68 to 39.5 mL/min (P = .007) after bypass. Hemispheres with maintained measurable bypass signal on postoperative NOVA demonstrated significant reduction in median collateral flow after bypass (P = .002). Median total hemispheric flow significantly increased from 227 mL/min to 247 mL/min (P = .007) after bypass. Only one patient suffered an ipsilateral ischemic stroke, and no patients suffered a hemorrhage during follow-up. CONCLUSION: NOVA measurements demonstrate a reduction in pial collateral flow and an increase in total hemispheric flow after bypass for MMD, likely representing a decrease in leptomeningeal collateral stress on the distal ACA and PCA territories. Further studies with these measures in larger cohorts may elucidate a role for NOVA in predicting the risk of ischemic and hemorrhagic events in MMD.

Far Lateral Approach With C1 Hemilaminotomy for Excision of a Ruptured Fusiform Lateral Spinal Artery Aneurysm: 2-Dimensional Operative Video.

The lateral spinal artery (LSA) represents the most rostral extent of the posterolateral arterial axis of the spinal cord and supplies both the posterior and lateral aspects of the spinal cord.1 The LSA originates from either the intradural segment of vertebral artery or the lateral segment of the posterior inferior cerebellar artery.1,2 It terminates at the level of C5 because it anastomoses with the posterior spinal artery. Although the LSA is in communication with the subarachnoid space, subarachnoid hemorrhage (SAH) due to an LSA aneurysm is rare.3-6 Moreover, accurate diagnosis of vascular pathologies involving the LSA is challenging because the LSA is typically too small to be visualized with conventional angiography.2 Here, we present the case of a 74-year-old woman who presented to our institution with headache, nausea, and confusion due to posterior fossa SAH without any visible vascular malformation on initial diagnostic cerebral angiography. A right frontal external ventricular drain was placed for communicating hydrocephalus. Immediate cerebral angiogram was within normal limits. Two-week follow-up angiogram demonstrated a fusiform right LSA aneurysm. The endovascular treatment was not an option because of the risk of occlusion of proximal perforators of the right posterior spinal artery, resulting in a long segment ischemia. The patient underwent a right far lateral transcondylar approach with C1 hemilaminotomy and excision of the LSA aneurysm. The postoperative course was uneventful. The patient was neurologically intact. Six-month follow-up angiogram showed no evidence of residual aneurysm. LSA pathologies should be kept in mind with posterior fossa SAH. Surgical excision is an effective treatment option in carefully selected patients. The patient consented to the procedure.

Efficacy and Safety of Endoscopic Transsphenoidal Resection for Prolactinoma: A Retrospective Multicenter Case-series.

BACKGROUND: Endoscopic transsphenoidal surgery (ETSS) for prolactinoma is reserved for dopamine agonist (DA) resistance, intolerance, or apoplexy. High remission (overall 67%, microprolactinoma up to 90%), low recurrence (5-20%) rates highlighted that surgery might be first-line treatment. AIMS: To report on outcomes of ETSS in a cohort of prolactinomas. METHODS: Multicenter retrospective cohort of 137 prolactinoma patients (age 38.2 ± 13.7 years; 61.3% female, median follow-up 28.0 [15.0-55.5] months) operated between 2010-2019 with histopathological confirmation. RESULTS: Median preoperative prolactin levels were 166 (98-837 µg/L; males 996 [159-2145 µg/L] vs. females 129 [84-223 µg/L], p <0.001). 56 (40.9%) microprolactinomas, 69 (50.4%) macroprolactinomas, and 7 (5.1%) giant prolactinomas were included, whereas no adenoma was detected in 5 (3.6%) patients. Males had larger tumors (macroprolactinomas: 38, 71.7%) vs. 31 (36.9%), p <0.001; giant prolactinomas: 7 (13.2%) vs. 0 (0.0%), (p <0.001). Prolactinomas were graded as KNOSP-3 in 15 (11.5%), and KNOSP-4 in 20 (15.3%) patients. Primary indication was DA intolerance (59, 43.1%); males 14 (26.4%) vs. females 45 (53.6%), p = 0.006. Long-term remission (i.e., DA-free prolactin level <1xULN) was achieved in 87 (63.5%) patients, being higher in intended complete resection (69/92 [75.0%]), and lower in males (25 [47.2%] vs. 62 females [73.8%], p = 0.002). Transient DI (n = 29, 21.2%) was the most frequent complication. CONCLUSIONS: Despite high proportions of macroprolactinoma and KNOSP 3-4, long-term remission rates were 63.5% overall, and 83.3% in microprolactinoma patients. Males had less favorable remission rate compared to females. These findings highlight that ETSS may be a safe and efficacious treatment to manage prolactinoma.

Postoperative stereotactic radiosurgery for intracranial solitary fibrous tumors: systematic review and pooled quantitative analysis.

BACKGROUND: Intracranial solitary fibrous tumors (SFTs), formerly hemangiopericytomas (HPCs), are rare, aggressive dural-based mesenchymal tumors. While adjuvant radiation therapy has been suggested to improve local tumor control (LTC), especially after subtotal resection, the role of postoperative stereotactic radiosurgery (SRS) and the optimal SRS dosing strategy remain poorly defined. METHODS: PubMed, EMBASE, and Web of Science were systematically searched according to PRISMA guidelines for studies describing postoperative SRS for intracranial SFTs. The search strategy was defined in the authors' PROSPERO protocol (CRD42023454258). RESULTS: 15 studies were included describing 293 patients harboring 476 intracranial residual or recurrent SFTs treated with postoperative SRS. At a mean follow-up of 21-77 months, LTC rate after SRS was 46.4-93% with a mean margin SRS dose of 13.5-21.7 Gy, mean maximum dose of 27-39.6 Gy, and mean isodose at the 42.5-77% line. In pooled analysis of individual tumor outcomes, 18.7% of SFTs demonstrated a complete SRS response, 31.7% had a partial response, 18.9% remained stable (overall LTC rate of 69.3%), and 30.7% progressed. When studies were stratified by margin dose, a mean margin dose > 15 Gy showed an improvement in LTC rate (74.7% versus 65.7%). CONCLUSIONS: SRS is a safe and effective treatment for intracranial SFTs. In the setting of measurable disease, our pooled data suggests a potential dose response of improving LTC with increasing SRS margin dose. Our improved understanding of the aggressive biology of SFTs and the tolerated adjuvant SRS parameters supports potentially earlier use of SRS in the postoperative treatment paradigm for intracranial SFTs.

Long-term outcomes of surgical clipping of saccular middle cerebral artery aneurysms: a consecutive series of 92 patients.

Despite advances in endovascular treatment, microsurgical clipping of middle cerebral artery (MCA) aneurysms remains appropriate. We review the high occlusion rate and treatment durability seen with surgical clipping of MCA aneurysms. We retrospectively reviewed patients who underwent microsurgical clipping of saccular MCA aneurysms by a single surgeon. Outcomes included aneurysm occlusion rate and durability, modified Rankin scale (mRS), and postoperative neurological morbidities. Ninety-two patients with 92 saccular MCA aneurysms were included, 50% of which were ruptured aneurysms. The mean follow-up period was 59 months. Complete aneurysm occlusion was achieved in all except one patient (99%) with near-complete occlusion. MCA aneurysm clipping was durable, with only one patient (1%) requiring retreatment after 4 years due to regrowth. Of the cohort, 79.3% achieved mRS 0-2 at last follow-up, including all with unruptured aneurysms. Poor outcome at discharge was associated with age > 65 (p = .03), postoperative neurological morbidities (p = .006), and aneurysm rupture (p < .001). Older age remained the single correlate for poor long-term outcome (p = .04). For ruptured aneurysms, predictors of poor long-term outcome included hemiparesis on presentation (p = .017), clinical vasospasm requiring treatment (p = .026), and infarction related to vasospasm (p = .041). Older age (p = .046) and complex anatomy (p = .036) were predictors of new postoperative neurological morbidities in the unruptured group. MCA aneurysm clipping is safe, durable, and should be considered first-line treatment for patients with saccular MCA aneurysms, especially in centers with abundant surgical experience.

Anterior-posterior diameter is a key driver of resectability and complications for pituitary adenomas with suprasellar extension in endoscopic transsphenoidal surgery.

BACKGROUND: As endoscopic transsphenoidal approaches are more routinely selected for progressively larger pituitary adenomas with parasellar extension, understanding potential anatomical factors that limit resection and contribute to complications is becoming increasingly important for tailoring a surgical approach. This study aimed to reevaluate existing predictive tools for resectability in pituitary adenomas specifically with suprasellar extension, and furthermore identify any additional measurable features that may be more useful in preoperative planning. METHODS: A single-center retrospective chart review of adult patients who underwent endoscopic transsphenoidal surgery for pituitary adenomas with suprasellar extension from 2015 to 2020 was performed. Preoperative MRIs were systematically assessed to assign a Knosp classification, a Zurich Pituitary Score (ZPS), and for dimensional measurements of the suprasellar aspect of the lesions. Univariate comparisons and multivariate regression models were employed to assess the influence of these factors on extent of resection and postoperative complications. RESULTS: Of the 96 patients with suprasellar pituitary adenomas who underwent endoscopic transsphenoidal surgery, 74 patients (77%) had a gross total resection (GTR). Neither Knosp grade nor ZPS score, even when dichotomized, demonstrated an association with GTR (Knosp 3A-4 versus Knosp 0-2, p = 0.069; ZPS III-IV versus ZPS I-II, p = 0.079). Multivariate regression analysis identified suprasellar anterior-posterior tumor diameter (SSAP) as the only significant predictor of extent of resection in this cohort (OR 0.951, 95% CI 0.905-1.000, p = 0.048*). A higher SSAP also had the strongest association with intraoperative CSF leaks (p = 0.0012*) and an increased overall rate of postoperative complications (p = 0.002*). Further analysis of the regression model for GTR suggested an optimal cut point value for SSAP of 23.7 mm, above which predictability for failing to achieve GTR carried a sensitivity of 89% and a specificity of 41%. CONCLUSIONS: This study is unique in its examination of endoscopic transsphenoidal surgical outcomes for pituitary adenomas with suprasellar extension. Our findings suggest that previously established grading systems based on lateral extension into the cavernous sinus lose their predictive value in lesions with suprasellar extension and, more specifically, with increasing suprasellar anterior-posterior diameter.

Extreme lateral infracondylar approach for internal jugular vein compression syndrome: A case series with preliminary clinical outcomes.

BACKGROUND AND OBJECTIVES: Internal jugular vein (IJV) stenosis is associated with several neurological disorders including idiopathic intracranial hypertension (IIH) and pulsatile tinnitus. In cases of extreme bony compression causing stenosis in the infracondylar region, surgical decompression might be necessary. We aim to examine the safety and efficacy of surgical IJV decompression. METHODS: We retrospectively reviewed patients who received surgical IJV decompression via the extreme lateral infracondylar (ELI) approach between July 2020 and February 2022. RESULTS: Fourteen patients with IJV stenosis were identified, all with persistent headache and/or tinnitus. Six patients were diagnosed with IIH, three of whom failed previous treatment. Of the eight remaining patients, two failed previous treatment. All underwent surgical IJV decompression via styloidectomy, release of soft tissue, and removal of the C1 transverse process (TP). Follow-up imaging showed significant improvement of IJV stenosis in eleven patients and mild improvement in three. Eight patients had significant improvement in their presenting symptoms, and three had partial improvement. Two patients received IJV stenting after a lack of initial improvement. Two patients experienced cranial nerve paresis, and one developed a superficial wound infection. CONCLUSION: The ELI approach for IJV decompression appears to be safe for patients who are not ideal endovascular candidates due to bony anatomy. Confirming long-term efficacy in relieving debilitating clinical symptoms requires longer follow-up and a larger patient cohort. Carefully selected patients with symptomatic bony IJV compression for whom there are no effective medical or endovascular options may benefit from surgical IJV decompression.

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.

Hyperperfusion syndrome after superficial temporal artery-middle cerebral artery bypass for non-moyamoya steno-occlusive disease.

BACKGROUND AND OBJECTIVES: Stroke is a major cause of morbidity and mortality worldwide, and intracranial stenoses increase the risk for stroke. Superficial temporal artery to middle cerebral artery bypass can be beneficial in selected patients with non-moyamoya steno-occlusive disease, however data is limited regarding the postoperative occurrence of hyperperfusion syndrome in this population. This case series describes the outcomes and complications, including hyperperfusion, in these patients who underwent bypass. METHODS: This is a retrospective review of bypass procedures done for medically refractory intracranial stenosis at a single institution by a single surgeon between 2014 and 2021. RESULTS: 30 patients underwent 33 bypass procedures for unequivocal non-moyamoya steno-occlusive disease. All patients had immediate bypass patency on post-operative day one. Major perioperative complications (9%) included one stroke and two cases of hyperperfusion syndrome. Minor perioperative complications (12%) included two seizures, one superficial wound infection and one deep vein thrombosis. Modified Rankin Score improved in 20 patients (74%), worsened in one patient (4%), and remained stable in seven patients (22%) at the last follow up. Twenty-three patients (85%) had scores ≤ 2. The recurrent stroke rate was 3% at 30 days and 7% at two years. The bypass patency rate at one year was 87.5%. CONCLUSION: In this series, bypass for patients with medically refractory non-moyamoya steno-occlusive disease was well tolerated and effective, with overall favorable outcomes. The occurrence of hyperperfusion syndrome is rare but significant and should be considered in post-operative management of this population.

A comparison of endovascular coil systems for the treatment of small intracranial aneurysms.

BACKGROUND: Endovascular coiling of small, intracranial aneurysms remains controversial and difficult, despite advances in technology. METHODS: We retrospectively reviewed data for 62 small aneurysms (<3.99 mm) in 59 patients. Occlusion rates, complications rates, and coil packing densities were compared between subgroups based upon coil type and rupture status. RESULTS: Ruptured aneurysms predominated (67.7%). Aneurysms measured 2.99 ± 0.63 mm by 2.51 ± 0.61 mm with an aspect ratio of 1.21 ± 0.34 mm. Brands included Optima (Balt) (29%), MicroVention Hydrogel (24.2%), and Penumbra SMART (19.4%) coil systems. Average packing density was 34.3 ± 13.5 mm3. Occlusion rate was 100% in unruptured aneurysms; 84% utilized adjuvant devices. For ruptured aneurysms, complete occlusion or stable neck remnant was achieved in 88.6% while recanalization occurred in 11.4%. No rebleeding occurred. Average packing density (p = 0.919) and coil type (p = 0.056) did not impact occlusion. Aspect ratio was smaller in aneurysms with technical complications (p = 0.281), and aneurysm volume was significantly smaller in those with coil protrusion (p = 0.018). Complication rates did not differ between ruptured and unruptured aneurysms (22.6 vs. 15.8%, p = 0.308) or coil types (p = 0.830). CONCLUSION: Despite advances in embolization devices, coiling of small intracranial aneurysms is still scrutinized. High occlusion rates are achievable, especially in unruptured aneurysms, with coil type and packing density suggesting association with complete occlusion. Technical complications may be influenced by aneurysm geometry. Advances in endovascular technologies have revolutionized small aneurysm treatment, with this series demonstrating excellent aneurysm occlusion especially in unruptured aneurysms.

Comparative outcomes of the treatment of unruptured paraophthalmic aneurysms in the era of flow diversion.

BACKGROUND: Paraophthalmic aneurysms present a challenge to surgeons and their ideal management remains up for debate. We studied recent outcomes of these lesions in a single center. METHODS: A retrospective chart review of all patients undergoing treatment for paraophthalmic aneurysms from 2017-2019 was performed. Factors including patient demographics, aneurysm characteristics, treatment modality, radiographic treatment outcome, clinical outcome, and length of stay were collected, and bivariate analysis was performed. RESULTS: In total 84.5% (82/97) of aneurysms were treated endovascularly and 15.5% (15/97) surgically. In the surgery cohort, there were three transient perioperative complications (20%) and one minor postoperative complication (6.7%). Complete aneurysm occlusion or near complete (<2mm residual) was achieved in 100% (15/15). All but one patient had mRS ≤1 at the last follow-up. In the endovascular group, 78.1% (64/82) underwent flow diversion alone. Endovascular treatment was associated with a 4.9% (4/82) rate of periprocedural complications: 3 transient events, and 1 death, and a 3.7% (3/82) rate of delayed complications: 2 transient vision changes, and one death. Rate of total occlusion was 87.8% (72/82). 76 patients (92.7%) had mRS ≤1 at the last follow-up. Length of stay was significantly shorter in the endovascular group (3.4 days vs. 7.0 days) [p < 0.001]. CONCLUSIONS: This series demonstrates similar safety to previously reported series as well as the efficacy of both surgical clipping and endovascular embolization of paraophthalmic aneurysms. Rate of complications and treatment efficacy were similar in both groups although this represents a single institution series not generalizable to all centers.

Disappearance of a small unruptured intracranial aneurysm: A case report and brief literature review.

Disappearing intracranial aneurysms are rare and have not been extensively reported in the literature. They are often small or partially thrombosed and carry a significant risk of recurrence. We discuss a unique case of a 65-year-old woman who presented in 2006 with a subarachnoid hemorrhage and was found to have a ruptured posterior communicating artery and an unruptured P1 aneurysm. Follow-up angiography and imaging showed no changes in the size of a left P1 aneurysm for 11 years (2006-2017). However, in 2021, 15 years after initial presentation, no aneurysm was seen on magnetic resonance angiography, and subsequent digital subtraction angiography in 2022 showed almost complete disappearance of the unruptured P1 aneurysm. Literature review reveals only six reported cases during which a small, unruptured anterior circulation aneurysm disappeared, or regressed on follow-up imaging and no reported cases in the posterior circulation.

Microsurgical Obliteration of Craniocervical Junction Dural Arteriovenous Fistulas: Multicenter Experience.

BACKGROUND: Dural arteriovenous fistulas (dAVFs) located at craniocervical junction are extremely rare (1%-2% of intracranial/spinal dAVFs). Their angio-architectural complexity renders endovascular embolization to be challenging given multiple small feeders with risk of embolysate reflux into vertebral artery and limited transvenous access. The available literature discussing microsurgery for these lesions is limited to few case reports. OBJECTIVE: To report a multicenter experience assessing microsurgery safety/efficacy. METHODS: Prospectively maintained registries at 13 North American centers were queried to identify craniocervical junction dAVFs treated with microsurgery (2006-2021). RESULTS: Thirty-eight patients (median age 59.5 years, 44.7% female patients) were included. The most common presentation was subarachnoid/intracranial hemorrhage (47.4%) and myelopathy (36.8%) (92.1% of lesions Cognard type III-V). Direct meningeal branches from V3/4 vertebral artery segments supplied 84.2% of lesions. All lesions failed (n = 5, 13.2%) or were deemed inaccessible/unsafe to endovascular treatment. Far lateral craniotomy was the most used approach (94.7%). Intraoperative angiogram was performed in 39.5% of the cases, with angiographic cure in 94.7% of cases (median imaging follow-up of 9.2 months) and retreatment rate of 5.3%. Favorable last follow-up modified Rankin Scale of 0 to 2 was recorded in 81.6% of the patients with procedural complications of 2.6%. CONCLUSION: Craniocervical dAVFs represent rare entity of lesions presenting most commonly with hemorrhage or myelopathy because of venous congestion. Microsurgery using a far lateral approach provides robust exposure and visualization for these lesions and allows obliteration of the arterialized draining vein intradurally as close as possible to the fistula point. This approach was associated with a high rate of angiographic cure and favorable clinical outcomes.

Angiographic Evaluation of Cranial Venous Outflow Patterns in Patients With and Without Idiopathic Intracranial Hypertension.

BACKGROUND: Several collateral venous pathways exist to assist in cranial venous drainage in addition to the internal jugular veins. The important extrajugular networks (EJN) are often readily identified on diagnostic cerebral angiography. However, the angiographic pattern of venous drainage through collateral EJN has not been previously compared among patients with and without idiopathic intracranial hypertension (IIH). OBJECTIVE: To quantify EJN on cerebral angiography among patients both with and without IIH and to determine whether there is a different EJN venous drainage pattern in patients with IIH. METHODS: Retrospective imaging review of 100 cerebral angiograms (50 IIH and 50 non-IIH patients) and medical records from a single academic medical center was performed by 2 independent experienced neuroendovascular surgeons. Points were assigned to EJN flow from 0 to 6 using an increasing scale (with each patient's dominant internal jugular vein standardized to 5 points to serve as the internal reference). Angiography of each patient included 11 separately graded extrajugular networks for internal carotid and vertebral artery injections. RESULTS: Patients in the IIH group had statistically significant greater flow in several of the extrajugular networks. Therefore, they preferentially drained through EJN compared with the non-IIH group. Right transverse-sigmoid system was most often dominant in both groups, yet there was a significantly greater prevalence of codominant sinus pattern on posterior circulation angiograms. CONCLUSION: Patients with IIH have greater utilization of EJN compared with patients without IIH. Whether this is merely an epiphenomenon or possesses actual cause-effect relationships needs to be determined with further studies.