De novo hemorrhagic sporadic cavernous malformation appearance after COVID-19 respiratory infection: illustrative case.

BACKGROUND: Little is known about whether coronavirus disease 2019 (COVID-19) influences cavernous malformation (CM) formation or hemorrhage risk. OBSERVATIONS: The authors present the case of a 31-year-old patient who developed a hemorrhagic, de novo CM in the setting of a developmental venous anomaly within 3 months of COVID-19 respiratory disease. The authors speculate that COVID-19 disease stimulated formation of the CM through TLR4 inflammatory pathways and subsequently led to the hemorrhagic presentation because of hypercoagulability related to the disease. LESSONS: This case raises the possibility that COVID-19 may be a risk factor for de novo development of CMs in predisposed patients.

Surgical approaches and long-term outcomes of intramedullary spinal cord cavernous malformations: a single-center consecutive series of 219 patients.

OBJECTIVE: Optimal surgical strategies for intramedullary spinal cord cavernous malformations (ISCCMs) are not optimized and remain problematic. In this study the authors identify rational surgical strategies for ISCCMs and predictors of outcomes after resection. METHODS: A single-center study was performed with 219 consecutive surgically treated patients who presented from 2002 to 2017 and were analyzed retrospectively. The American Spinal Injury Association (ASIA) Impairment Scale was used to evaluate neurological functions. Patient characteristics, surgical approaches, and immediate and long-term postoperative outcomes were identified. RESULTS: The average ISCCM size was 10.5 mm. The spinal level affected was cervical in 24.8% of patients, thoracic in 73.4%, and lumbar in 1.8%. The locations of the lesions in the horizontal plane were 30.4% ventral, 41.6% dorsal, and 28.0% central. Of the 214 patients included in the cohort for operative evaluation, 62.6% had superficially located lesions, while 37.4% were embedded. Gross-total resection was achieved in 98.1% of patients. The immediate postoperative neurological condition worsened in 10.3% of the patients. Multivariate logistic regression identified mild preoperative function (p = 0.014, odds ratio [OR] 4.5, 95% confidence interval [CI] 1.4-14.8) and thoracolumbar-level lesions (p = 0.01, OR 15.7, 95% CI 1.9-130.2) as independent predictors of worsening. The mean follow-up duration in 187 patients was 45.9 months. Of these patients, 63.1% were stable, 33.2% improved, and 3.7% worsened. Favorable outcomes were observed in 86.1% of patients during long-term follow-up and were significantly associated with preoperative mild neurological and disability status (p = 0.000) and cervically located lesions (p = 0.009). The depths of the lesions were associated with worse long-term outcomes (p = 0.001), and performing myelotomy directly through a yellowish abnormal surface in moderate-depth lesions was an independent predictor of worsening (p = 0.023, OR 35.3, 95% CI 1.6-756.3). CONCLUSIONS: Resection performed with an individualized surgical approach remains the primary therapeutic option in ISCCMs. Performing surgery in patients with mild symptoms at the thoracolumbar level and embedded located lesions requires more discretion.

Contemporary radiosurgery of cerebral cavernous malformations: Part 1. Treatment outcome for critically located hemorrhagic lesions.

OBJECTIVELong-term benefits of radiosurgery (RS) applying modern protocols to treat cavernous malformations (CMs) remain unclear as critics may consider the decrease in the rebleed rate generally observed 2 years after RS as a reflection of the lesion's natural history. The authors adopted an early intention-to-treat attitude since rehemorrhage from deep-seated CMs ultimately leads to stepwise neurological deterioration. The safety of this early policy was previously demonstrated. Here, the authors revisit their current practice in a larger population with a longer follow-up time to assess the long-term effects of RS in the context of current knowledge on the natural history of CMs.METHODSThe authors conducted a retrospective analysis of 210 patients with 210 hemorrhagic CMs located in the brainstem, thalamus, or basal ganglia and treated with Gamma Knife RS between 1995 and 2014. Two hundred six patients had available follow-up, which was a median of 5.5 years (range 1-20 years). The median age was 37 years (0.5-77 years) at presentation and 43 (2-78) at treatment. One hundred twenty-seven CMs had bled once and 83 had had multiple hemorrhages prior to treatment.RESULTSThe lifetime annual bleed rate of CMs having a single hemorrhage prior to treatment was 2.4% per lesion. The hemorrhage rate stabilized at 1.1% after a temporary increase of 4.3% within the first 2 years after RS. The annual pretreatment hemorrhage rate was 2.8% for the lesions having multiple bleeds prior to RS with a pretreatment rebleed rate of 20.7% and with a modest gradual decrease within the first 5 years and remaining stable at 11.55% thereafter. The rebleed rate fell to 7.9% for the first 2 years after RS and declined further to 1.3% thereafter, which was significantly lower than the long-term pretreatment rebleed risk. The rate of hemorrhage-free survival remained 86.4% and 75.1% (1 patient each) at 20 years after RS in the single- and multiple-bleed groups, respectively.Pretreatment hemorrhages resulted in permanent deficits in 48.8% of the cases with a single bleed and in 77.1% of the cases with multiple bleeds. Both the rate and severity of deficits were significantly lower in the first group. Only mild and a low rate of permanent neurological deficits were caused either by posttreatment hemorrhages (7.4%) or by radiation (7.2%). The rate of persistent morbidity in the single-bleed group remained significantly lower at the end of the study than pretreatment morbidity in the multiple-bleed group (OR 2.9, 95% CI 1.6-5.3). Lesion-specific mortality was < 1%.CONCLUSIONSThe hemorrhage rate of CMs after RS remained low after the first 2 years during the longer follow-up period. The benefit of early treatment appears to be confirmed by the study results as repeated hemorrhages carry the risk of significantly higher cumulative morbidity than the morbidity associated with RS.

Contemporary radiosurgery of cerebral cavernous malformations: Part 2. Treatment outcome for hemispheric lesions.

OBJECTIVEThe role of radiosurgery (RS) in treating superficial cavernous malformations (CMs) is insufficiently studied in part because of the disappointing results of early experimental attempts as compared to the mostly safe and effective microsurgery. Nonetheless, because of lesion- or treatment-specific factors, a therapeutic alternative may be required. In this study, the authors aimed to assess the safety of RS in treating superficial CMs and to analyze its long-term effect on hemorrhage rates and epilepsy control.METHODSThe authors conducted a retrospective analysis of 96 patients with 109 CMs located in the cerebral or cerebellar hemispheres and treated with RS between 1995 and 2014. A median of 15 Gy (range 10-25 Gy) was given to the 50% prescription isodose level, lesion volume was 604 mm3 (4-8300 mm3), and the prescription isodose volume was 638.5 mm3 (4-9500 mm3). Outcomes were compared to those of 206 deep-seated lesions reported on in another study. Ninety-five patients had available follow-up, which was a median of 7 years (1-21 years). Median patient age was 42 years (0.5-77) at presentation and 45 (3-80) at treatment. Seventy-one CMs presented with symptomatic hemorrhage, and 52 caused seizures.RESULTSIn the nonhemorrhagic group (37 lesions), one bleed occurred during the follow-up period, for an annual bleed rate of 0.4% per lesion. The lifetime annual bleed rate of CMs having a single hemorrhage prior to treatment was 2.5%. The rebleed rate in the single-bleed group decreased from 1.8% within the first 2 years after RS to 0.7% thereafter. The pretreatment rebleed rate for lesions having multiple bleeds prior to RS was 14.15%, which fell to 3.85% for the first 2 years after RS and declined to 1.3% thereafter. Multivariate analysis showed younger age, deep lesion location, and multiple pretreatment hemorrhages as significant predictors of posttreatment hemorrhage.Pretreatment hemorrhages led to permanent deficits in 41.4% of the cases with a single bleed and in 46.1% of cases with multiple bleeds. Only mild (modified Rankin Scale score 1) and a low rate of permanent neurological deficits were caused either by posttreatment hemorrhages (4.3%) or by radiation (2%).The rate of improvement in epilepsy was 84.9% after RS in patients with at least one seizure prior to treatment, not depending on the presence of hemorrhage or the time interval between presentation and treatment. Favorable outcome occurred in 81% of patients whose seizures were not controlled with antiepileptic medication prior to RS.CONCLUSIONSRadiosurgery for superficial CMs is safe and appears to be effective, offering a real treatment alternative to surgery for selected patients. Given their relatively benign natural history, superficial CMs require further study to verify the long-term benefit of RS over the lesions' natural history.

The oculomotor-tentorial triangle. Part 2: a microsurgical workspace for vascular lesions in the crural and ambient cisterns.

OBJECTIVEPathology in the region of the basilar quadrifurcation, anterolateral midbrain, medial tentorium, and interpeduncular and ambient cisterns may be accessed anteriorly via an orbitozygomatic (OZ) craniotomy. In Part 1 of this series, the authors explored the anatomy of the oculomotor-tentorial triangle (OTT). In Part 2, the versatility of the OTT as a surgical workspace for treating vascular pathology is demonstrated.METHODSSixty patients with 61 vascular pathologies treated within or via the OTT from 1998 to 2017 by the senior author were retrospectively reviewed. Patients were grouped together based on pathology/surgical procedure and included 1) aneurysms (n = 19); 2) posterior cerebral artery (PCA)/superior cerebellar artery (SCA) bypasses (n = 24); 3) brainstem cavernous malformations (CMs; n = 14); and 4) tentorial region dural arteriovenous fistulas (dAVFs; n = 4). The majority of patients were approached via an OZ craniotomy, wide sylvian fissure split, and temporal lobe mobilization to widen the OTT.RESULTSAneurysm locations included the P1-P2 junction (n = 7), P2A segment (n = 9), P2/3 (n = 2), and basilar quadrification (n = 1). Aneurysm treatments included clip reconstruction (n = 12), wrapping (n = 3), proximal occlusion (n = 2), and trapping with (n = 1) or without (n = 1) bypass. Pathologies in the bypass group included vertebrobasilar insufficiency (VBI; n = 3) and aneurysms of the basilar trunk (n = 13), basilar apex (n = 4), P1 PCA (n = 2), and s1 SCA (n = 2). Bypasses included M2 middle cerebral artery (MCA)-radial artery graft (RAG)-P2 PCA (n = 8), M2 MCA-saphenous vein graft (SVG)-P2 PCA (n = 3), superficial temporal artery (STA)-P2 PCA (n = 5) or STA-s1 SCA (n = 3), s1 SCA-P2 PCA (n = 1), V3 vertebral artery (VA)-RAG-s1 SCA (n = 1), V3 VA-SVG-P2 PCA (n = 1), anterior temporal artery-s1 SCA (n = 1), and external carotid artery (ECA)-SVG-s1 SCA (n = 1). CMs were located in the midbrain (n = 10) or pontomesencephalic junction (n = 4). dAVFs drained into the tentorial, superior petrosal, cavernous, and sphenobasal sinuses. High rates of aneurysm occlusion (79%), bypass patency (100%), complete CM resection (86%), and dAVF obliteration (100%) were obtained. The overall rate of permanent oculomotor nerve palsy was 8.3%. The majority of patients in the aneurysm (94%), CM (93%), and dAVF (100%) groups had stable or improved modified Rankin Scale scores.CONCLUSIONSThe OTT is an important anatomical triangle and surgical workspace for vascular lesions in and around the crural and ambient cisterns. The OTT can be used to approach a wide variety of vascular pathologies in the region of the basilar quadrifurcation and anterolateral midbrain.

Surgical outcome of motor deficits and neurological status in brainstem cavernous malformations based on preoperative diffusion tensor imaging: a prospective randomized clinical trial.

OBJECTIVE: Surgical management of brainstem lesions is challenging due to the highly compact, eloquent anatomy of the brainstem. This study aimed to evaluate the safety and efficacy of preoperative diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) in brainstem cavernous malformations (CMs). METHODS: A prospective randomized controlled clinical trial was performed by using stratified blocked randomization. The primary eligibility criterion of the study was being a surgical candidate for brainstem CMs (with informed consent). The study enrolled 23 patients who underwent preoperative DTI/DTT and 24 patients who did not (the control group). The pre- and postoperative muscle strength of both limbs and modified Rankin Scale (mRS) scores were evaluated. Muscle strength of any limb at 12 months after surgery at the clinic visit was the primary outcome; worsened muscle strength was considered to be a poor outcome. Outcome assessors were blinded to patient management. This study reports the preliminary results of the interim analysis. RESULTS: The cohort included 47 patients (22 women) with a mean age of 35.7 years. The clinical baselines between these 2 groups were not significantly different. In the DTI/DTT group, the corticospinal tract was affected in 17 patients (73.9%): it was displaced, deformed/partially interrupted, or completely interrupted in 6, 7, and 4 patients, respectively. The surgical approach and brainstem entry point were adjusted in 3 patients (13.0%) based on DTI/DTT data. The surgical morbidity of the DTI/DTT group (7/23, 30.4%) was significantly lower than that of the control group (19/24, 79.2%, p = 0.001). At 12 months, the mean mRS score (1.1, p = 0.034) and percentage of patients with worsened motor deficits (4.3%, p = 0.006) were significantly lower in the DTI/DTT group than in the control group (1.7% and 37.5%). Multivariate logistic regression identified the absence of preoperative DTI/DTT (OR 0.06, 95% CI 0.01-0.73, p = 0.028) and use of the 2-point method (OR 4.15, 95% CI 1.38-12.49, p = 0.011) as independent adverse factors for a worsened motor deficit. The multivariate model found a significant correlation between poor mRS score and both an increased preoperative mRS score (t = 3.559, p = 0.001) and absence of preoperative DTI/DTT (t = -2.747, p = 0.009). CONCLUSIONS: DTI/DTT noninvasively allowed for visualization of the anatomical relationship between vital tracts and pathologies as well as facilitated the brainstem surgical approach and entry-point decision making. The technique was valuable for complex neurosurgical planning to reduce morbidity. Nonetheless, DTI/DTT data should be interpreted cautiously.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: randomized controlled trial; evidence: class I. Clinical trial registration no.: NCT01758211 (ClinicalTrials.gov).

Supratentorial cavernous malformations adjacent to the corticospinal tract: surgical outcomes and predictive value of diffusion tensor imaging findings.

OBJECTIVE Diffusion tensor imaging (DTI) findings may facilitate clinical decision making in patients with supratentorial cavernous malformations adjacent to the corticospinal tract (CST-CMs). The objective of this study was to determine the predictive value of preoperative DTI findings for surgical outcomes in patients with CST-CMs. METHODS A prospectively maintained database of patients with CM referred to the authors' hospital between September 2012 and October 2015 was reviewed to identify all consecutive surgically treated patients with CST-CM. All patients had undergone sagittal T1-weighted anatomical imaging and DTI before surgery. Both DTI findings and clinical characteristics of the patients and lesions were analyzed with respect to surgery-related motor deficits. DTI findings included lesion-to-CST distance (LCD) and the alteration (i.e., deviation, interruption, or degeneration due to the CM) of CST on preoperative DTI images. Surgery-related motor deficits at 1 week and the last clinic visit (≥ 3 months) after surgery were defined as short-term and long-term deficits, respectively. Preoperative and final modified Rankin Scale scores were also analyzed to identify the surgical outcomes in these patients. RESULTS A total of 56 patients with 56 CST-CMs were included in this study. The mean LCD was 3.9 ± 3.2 mm, and alterations of the CST were detected in 20 (36.7%) patients. One week after surgery, 21 (37.5%) patients had short-term surgery-related motor deficits, but only 14 (25.0%) patients had long term deficits at the last clinical visit. The mean patient follow-up was 14.7 ± 10.1 months. The difference between preoperative and final modified Rankin Scale scores was not statistically significant (p = 0.490). Multivariate analysis showed that both short-term (p < 0.001) and long-term (p = 0.002) surgery-related motor deficits were significantly associated with LCD. Receiver operating characteristic (ROC) curve results were as follows: for short-term surgery-related motor deficits, the area under the ROC curve (AUC) was 0.860, and the cutoff point was LCD = 2.55 mm; for long-term deficits, the AUC was 0.894, and the cutoff point was LCD = 2.30 mm. Both univariate (p = 0.012) and multivariate (p = 0.049) analyses revealed that CST alteration on preoperative DTI was significantly correlated with short-term surgery-related motor deficits. On univariate analysis, deep location of the CST-CMs was significantly correlated with long-term motor deficits (p = 0.016). Deep location of the CST-CMs had a trend toward significance with long-term motor deficits on the multivariate analysis (p = 0.060). CONCLUSIONS To facilitate clinical practice, the authors propose that 3.00 mm (2.55 to ∼3.00 mm) may be the safe LCD for surgery in patients with CST-CMs. A CST alteration on preoperative DTI and a deep location of the CST-CM may be risk factors for short- and long-term surgery-related motor deficits, respectively. A randomized controlled trial is needed to demonstrate the predictive value of preoperative DTI findings on surgical outcomes in patients with CST-CMs in future studies.

Emergency resection of brainstem cavernous malformations.

Brainstem cavernous malformations (CMs) pose significant challenges to neurosurgeons because of their deep locations and high surgical risks. Most patients with brainstem CMs present with sudden-onset cranial nerve deficits or ataxia, but uncommonly patients can present in extremis from an acute hemorrhage, requiring surgical intervention. However, the timing of surgery for brainstem CMs has been a controversial topic. Although many authors propose delaying surgery into the subacute phase, some patients may not tolerate waiting until surgery. To the best of the authors' knowledge, emergency surgery after a brainstem CM hemorrhage has not been described. In cases of rapidly progressive neurological deterioration, emergency resection may often be the only option. In this retrospectively reviewed small series of patients, the authors report favorable outcomes after emergency surgery for resection of brainstem CMs.

De novo formation of a large cavernoma associated with a congenital torcular dural arteriovenous fistula: case report.

The authors report a case of a developmentally normal child with a congenital complex torcular dural arteriovenous fistula (DAVF) who later, in his teenage years, developed several vermian cavernomas within a large cerebellar developmental venous anomaly (DVA). The patient had initially presented with an abnormally large head circumference but no neurological deficits. He underwent several partial embolization procedures in an attempt to decrease the blood supply of the fistula over the course of 8 years. Nine years following initial presentation, he presented with a fourth ventricular hemorrhage, due to development of a new vermian cavernoma adjacent to a previously known vermian DVA and suffered subsequent mild left-sided hemiataxia from which he later recovered. CT angiographic images demonstrated that the vermian DVA drained into the left transverse sinus, which also drained the torcular arteriovenous fistula. A routine follow-up MRI examination 10 years following initial presentation demonstrated interval development of several large cavernomas in the cerebellum, all within the DVA. The patient had no new symptoms at that time and was neurologically intact. This case report highlights the de novo development of multiple cavernous malformations potentially secondary to DAVF-induced venous congestion in a preexisting DVA.

Performing concurrent operations in academic vascular neurosurgery does not affect patient outcomes.

OBJECTIVE Concurrent surgeries, also known as "running two rooms" or simultaneous/overlapping operations, have recently come under intense scrutiny. The goal of this study was to evaluate the operative time and outcomes of concurrent versus nonconcurrent vascular neurosurgical procedures. METHODS The authors retrospectively reviewed 1219 procedures performed by 1 vascular neurosurgeon from 2012 to 2015 at the University of California, San Francisco. Data were collected on patient age, sex, severity of illness, risk of mortality, American Society of Anesthesiologists (ASA) status, procedure type, admission type, insurance, transfer source, procedure time, presence of resident or fellow in operating room (OR), number of co-surgeons, estimated blood loss (EBL), concurrent vs nonconcurrent case, severe sepsis, acute respiratory failure, postoperative stroke causing neurological deficit, unplanned return to OR, 30-day mortality, and 30-day unplanned readmission. For aneurysm clipping cases, data were also obtained on intraoperative aneurysm rupture and postoperative residual aneurysm. Chi-square and t-tests were performed to compare concurrent versus nonconcurrent cases, and then mixed-effects models were created to adjust for different procedure types, patient demographics, and clinical indicators between the 2 groups. RESULTS There was a significant difference in procedure type for concurrent (n = 828) versus nonconcurrent (n = 391) cases. Concurrent cases were more likely to be routine/elective admissions (53% vs 35%, p < 0.001) and physician referrals (59% vs 38%, p < 0.001). This difference in patient/case type was also reflected in the lower severity of illness, risk of death, and ASA class in the concurrent versus nonconcurrent cases (p < 0.01). Concurrent cases had significantly longer procedural times (243 vs 213 minutes) and more unplanned 30-day readmissions (5.7% vs 3.1%), but shorter mean length of hospital stay (11.2 vs 13.7 days), higher rates of discharge to home (66% vs 51%), lower 30-day mortality rates (3.1% vs 6.1%), lower rates of acute respiratory failure (4.3% vs 8.2%), and decreased 30-day unplanned returns to the OR (3.3% vs 6.9%; all p < 0.05). Rates of severe sepsis, postoperative stroke, intraoperative aneurysm rupture, and postoperative aneurysm residual were equivalent between the concurrent and nonconcurrent groups (all p values nonsignificant). Mixed-effects models showed that after controlling for procedure type, patient demographics, and clinical indicators, there was no significant difference in acute respiratory failure, severe sepsis, 30-day readmission, postoperative stroke, EBL, length of stay, discharge status, or intraoperative aneurysm rupture between concurrent and nonconcurrent cases. Unplanned return to the OR and 30-day mortality were significantly lower in concurrent cases (odds ratio 0.55, 95% confidence interval 0.31-0.98, p = 0.0431, and odds ratio 0.81, p < 0.001, respectively), but concurrent cases had significantly longer procedure durations (odds ratio 21.73; p < 0.001). CONCLUSIONS Overall, there was a significant difference in the types of concurrent versus nonconcurrent cases, with more routine/elective cases for less sick patients scheduled in an overlapping fashion. After adjusting for patient demographics, procedure type, and clinical indicators, concurrent cases had longer procedure times, but equivalent patient outcomes, as compared with nonconcurrent vascular neurosurgical procedures.

Clinical course of untreated thalamic cavernous malformations: hemorrhage risk and neurological outcomes.

OBJECTIVE The natural history of cerebral cavernous malformations (CMs) has been widely studied, but the clinical course of untreated thalamic CMs is largely unknown. Hemorrhage of these lesions can be devastating. The authors undertook this study to obtain a prospective hemorrhage rate and provide a better understanding of the prognosis of untreated thalamic CMs. METHODS This longitudinal cohort study included patients with thalamic CMs who were diagnosed between 2000 and 2015. Clinical data were recorded, radiological studies were extensively reviewed, and follow-up evaluations were performed. RESULTS A total of 121 patients were included in the study (56.2% female), with a mean follow-up duration of 3.6 years. The overall annual hemorrhage rate (subsequent to the initial presentation) was calculated to be 9.7% based on the occurrence of 42 hemorrhages over 433.1 patient-years. This rate was highest in patients (n = 87) who initially presented with hemorrhage and focal neurological deficits (FNDs) (14.1%) (χ2 = 15.358, p < 0.001), followed by patients (n = 19) with hemorrhage but without FND (4.5%) and patients (n = 15) without hemorrhage regardless of symptoms (1.2%). The initial patient presentations of hemorrhage with FND (hazard ratio [HR] 2.767, 95% CI 1.336-5.731, p = 0.006) and associated developmental venous anomaly (DVA) (HR 2.510, 95% CI 1.275-4.942, p = 0.008) were identified as independent hemorrhage risk factors. The annual hemorrhage rate was significantly higher in patients with hemorrhagic pres entation at diagnosis (11.7%, p = 0.004) or DVA (15.7%, p = 0.002). Compared with the modified Rankin Scale (mRS) score at diagnosis (mean 2.2), the final mRS score (mean 2.0) was improved in 37 patients (30.6%), stable in 59 patients (48.8%), and worse in 25 patients (20.7%). Lesion size (odds ratio [OR] per 0.1 cm increase 3.410, 95% CI 1.272-9.146, p = 0.015) and mRS score at diagnosis (OR per 1 point increase 3.548, 95% CI 1.815-6.937, p < 0.001) were independent adverse risk factors for poor neurological outcome (mRS score ≥ 2). Patients experiencing hemorrhage after the initial ictus (OR per 1 ictus increase 6.923, 95% CI 3.023-15.855, p < 0.001) had a greater chance of worsened neurological status. CONCLUSIONS This study verified the adverse predictors for hemorrhage and functional outcomes of thalamic CMs and demonstrated an overall annual symptomatic hemorrhage rate of 9.7% after the initial presentation. These findings and the mode of initial presentation are useful for clinicians and patients when selecting an appropriate treatment, although the tertiary referral bias of the series should be taken into account.

Occipital transtentorial/falcine approach, a "cross-court" trajectory to accessing contralateral posterior thalamic lesions: case report.

Surgical treatment of lesions in the posterior thalamus, especially those extending laterally, is technically challenging because of a deep surgical field, narrow operative corridor, and the surrounding critical neurovascular structures. The authors describe an occipital transtentorial/falcine approach (OTFA) that was successfully used in the treatment of a cavernous malformation (CM) extending laterally from thalamus to midbrain. A 40-year-old man complained of progressive right hemiparesis and numbness. Radiological evaluation revealed a large CM in the left thalamus, surfacing on the pulvinar thalami, and extending 4 cm laterally from the midline. In addition to the usual procedures of a right-sided occipital transtentorial approach, the authors incised the falx cerebri to expand the operative corridor to the left thalamus. They achieved generous exposure of the left thalamus through a "cross-court" oblique trajectory while avoiding excessive retraction on the occipital lobe. The CM was completely removed, and no newly developed or worsening deficits were detected postoperatively. To better understand the OTFA and its application, the authors performed a cadaveric dissection. The OTFA provides increased exposure of the posterior thalamus without cortical incision and facilitates lateral access to this area through the "cross-court" operative corridor. This approach adds to the armamentarium for neurosurgeons treating thalamic lesions.

Endoscopic endonasal transclival resection of a ventral pontine cavernous malformation: technical case report.

Brainstem cavernous malformations are challenging due to the critical anatomy and potential surgical risks. Anterolateral, lateral, and dorsal surgical approaches provide limited ventral exposure of the brainstem. The authors present a case of a midline ventral pontine cavernous malformation resected through an endoscopic endonasal transclival approach based on minimal brainstem transection, negligible cranial nerve manipulation, and a straightforward trajectory. Technical and reconstruction technique advances in endoscopic endonasal skull base surgery provide a direct, safe, and effective corridor to the brainstem.

Hemorrhage from cerebral cavernous malformations: a systematic pooled analysis.

OBJECTIVE The aim of this paper is to define an overall cavernous malformation (CM) hemorrhage rate and risk factors for hemorrhage. METHODS The authors performed a systematic, pooled analysis via the PubMed database through October 2015 using the terms "cavernoma," "cavernous malformation," "natural history," "bleeding," and "hemorrhage." English-language studies providing annual rates and/or risk factors for CM hemorrhage were included. Data extraction, performed independently by the authors, included demographic data, hemorrhage rates, and hemorrhage risk factors. RESULTS Across 12 natural history studies with 1610 patients, the mean age at presentation was 42.7 years old and 52% of patients (95% CI 49%-55%) were female. Presentation modality was seizure in 30% (95% CI 25%-35%), hemorrhage in 26% (95% CI 17%-37%), incidental in 17% (95% CI 9%-31%), and focal deficits only in 16% of cases (95% CI 11%-23%). CM location was lobar in 66% (95% CI 61%-70%), brainstem in 18% (95% CI 13%-24%), deep supratentorial in 8% (95% CI 6%-10%), and cerebellar in 8% (95% CI 5%-11%). Pooling 7 studies that did not assume CM presence since birth, the annual hemorrhage rate was 2.5% per patient-year over 5081.2 patient-years of follow-up (95% CI 1.3%-5.1%). Pooling hazard ratios across 5 studies that evaluated hemorrhage risk factors, prior CM hemorrhage was a significant risk factor for hemorrhage (HR 3.73, 95% CI 1.26-11.1; p = 0.02) while younger age, female sex, deep location, size, multiplicity, and associated developmental venous anomalies (DVAs) were not. CONCLUSIONS Although limited by the heterogeneity of incorporated reports and selection bias, this study found prior hemorrhage to be a significant risk factor for CM bleeding, while age, sex, CM location, size, multiplicity, and associated DVAs were not. Future natural history studies should compound annual hemorrhage rate with prospective seizure and nonhemorrhagic neurological deficit rates.

Worldwide variance in the potential utilization of Gamma Knife radiosurgery.

OBJECTIVE The role of Gamma Knife radiosurgery (GKRS) has expanded worldwide during the past 3 decades. The authors sought to evaluate whether experienced users vary in their estimate of its potential use. METHODS Sixty-six current Gamma Knife users from 24 countries responded to an electronic survey. They estimated the potential role of GKRS for benign and malignant tumors, vascular malformations, and functional disorders. These estimates were compared with published disease epidemiological statistics and the 2014 use reports provided by the Leksell Gamma Knife Society (16,750 cases). RESULTS Respondents reported no significant variation in the estimated use in many conditions for which GKRS is performed: meningiomas, vestibular schwannomas, and arteriovenous malformations. Significant variance in the estimated use of GKRS was noted for pituitary tumors, craniopharyngiomas, and cavernous malformations. For many current indications, the authors found significant variance in GKRS users based in the Americas, Europe, and Asia. Experts estimated that GKRS was used in only 8.5% of the 196,000 eligible cases in 2014. CONCLUSIONS Although there was a general worldwide consensus regarding many major indications for GKRS, significant variability was noted for several more controversial roles. This expert opinion survey also suggested that GKRS is significantly underutilized for many current diagnoses, especially in the Americas. Future studies should be conducted to investigate health care barriers to GKRS for many patients.

Association between trauma and acute hemorrhage of cavernous malformations in children: report of 3 cases.

OBJECTIVE Cavernous hemangiomas are benign congenital vascular abnormalities. Intracerebral cavernous hemangiomas have an appreciable risk of spontaneous hemorrhage. Little is known as to whether head trauma increases the risk of bleeding for these lesions. In this study, the authors present a case series of 3 patients with posttraumatic nonspontaneous hemorrhage of intracerebral cavernous malformations (CMs). For the first time, to the authors' knowledge, they propose that trauma might constitute a risk factor for acute hemorrhage in intracerebral cavernomas. METHODS The authors reviewed the charts of all patients with a new diagnosis of intracerebral cavernoma at their pediatric hospital between 2010 and 2014. Patients with a history of head trauma prior to presentation were subsequently studied to identify features common to these posttraumatic, hemorrhage-prone lesions. RESULTS A history of head trauma was identified in 3 of 19 cases. These 3 patients presented with seizures and/or headaches and were found to have acute hemorrhage within a cavernous hemangioma. None of these patients had any history of abnormal neurological symptoms. All 3 abnormal vascular lesions had associated developmental venous anomalies (DVAs). The 3 patients underwent resection of their respective vascular abnormalities, and the diagnosis of cavernous hemangioma was confirmed with postsurgical tissue pathology. All 3 patients had complete resolution of symptoms following complete excision of their lesions. CONCLUSIONS Trauma may represent a risk factor for acute hemorrhage in patients with CMs. The presence of associated DVAs may represent a risk factor for posttraumatic hemorrhage of cavernomas. Excision should be considered in such cases, if feasible.

Resective surgery for medically refractory epilepsy using intraoperative MRI and functional neuronavigation: the Erlangen experience of 415 patients.

OBJECTIVE: Intraoperative overestimation of resection volume in epilepsy surgery is a well-known problem that can lead to an unfavorable seizure outcome. Intraoperative MRI (iMRI) combined with neuronavigation may help surgeons avoid this pitfall and facilitate visualization and targeting of sometimes ill-defined heterogeneous lesions or epileptogenic zones and may increase the number of complete resections and improve seizure outcome. METHODS: To investigate this hypothesis, the authors conducted a retrospective clinical study of consecutive surgical procedures performed during a 10-year period for epilepsy in which they used neuronavigation combined with iMRI and functional imaging (functional MRI for speech and motor areas; diffusion tensor imaging for pyramidal, speech, and visual tracts; and magnetoencephalography and electrocorticography for spike detection). Altogether, there were 415 patients (192 female and 223 male, mean age 37.2 years; 41% left-sided lesions and 84.9% temporal epileptogenic zones). The mean preoperative duration of epilepsy was 17.5 years. The most common epilepsy-associated pathologies included hippocampal sclerosis (n = 146 [35.2%]), long-term epilepsy-associated tumor (LEAT) (n = 67 [16.1%]), cavernoma (n = 45 [10.8%]), focal cortical dysplasia (n = 31 [7.5%]), and epilepsy caused by scar tissue (n = 23 [5.5%]). RESULTS: In 11.8% (n = 49) of the surgeries, an intraoperative second-look surgery (SLS) after incomplete resection verified by iMRI had to be performed. Of those incomplete resections, LEATs were involved most often (40.8% of intraoperative SLSs, 29.9% of patients with LEAT). In addition, 37.5% (6 of 16) of patients in the diffuse glioma group and 12.9% of the patients with focal cortical dysplasia underwent an SLS. Moreover, iMRI provided additional advantages during implantation of grid, strip, and depth electrodes and enabled intraoperative correction of electrode position in 13.0% (3 of 23) of the cases. Altogether, an excellent seizure outcome (Engel Class I) was found in 72.7% of the patients during a mean follow-up of 36 months (range 3 months to 10.8 years). The greatest likelihood of an Engel Class I outcome was found in patients with cavernoma (83.7%), hippocampal sclerosis (78.8%), and LEAT (75.8%). Operative revisions that resulted from infection occurred in 0.3% of the patients, from hematomas in 1.6%, and from hydrocephalus in 0.8%. Severe visual field defects were found in 5.2% of the patients, aphasia in 5.7%, and hemiparesis in 2.7%, and the total mortality rate was 0%. CONCLUSIONS: Neuronavigation combined with iMRI was beneficial during surgical procedures for epilepsy and led to favorable seizure outcome with few specific complications. A significantly higher resection volume associated with a higher chance of favorable seizure outcome was found, especially in lesional epilepsy involving LEAT or diffuse glioma.

The natural history of cerebral cavernous malformations in children.

OBJECT Cerebral cavernous malformations (CMs) are a source of neurological morbidity from seizures and focal neurological deficits due to mass effect and hemorrhage. Although several natural history reports exist for adults with CMs, similar data for pediatric patients are limited. METHODS The authors reviewed hospital databases to identify children with CMs who had not been treated surgically and who had clinical and radiological follow-up. Annual hemorrhage rates were calculated in lesion-years, and risk factors were assessed using the Cox proportional hazards model. RESULTS In a cohort of 167 patients with 222 CMs, the mean patient age at the time of diagnosis was 10.1 years old (SD 6.0). Ninety patients (54%) were male. One hundred four patients (62%) presented with hemorrhage from at least 1 CM, 58 (35%) with seizures with or without CM hemorrhage, and 43 (26%) with incidental lesions. Twenty-five patients (15%) had multiple CMs, 17 (10%) had a family history of CMs, and 33 (20%) had radiologically apparent developmental venous anomalies (DVAs). The overall annual hemorrhage rate was 3.3%. Permanent neurological morbidity was 29% per hemorrhage, increasing to 45% for brainstem, thalamic, or basal ganglia CM and decreasing to 15% for supratentorial lobar or cerebellar lesions. The annual hemorrhage rate for incidental CMs was 0.5%; for hemorrhagic CMs, it was 11.3%, increasing to 18.2% within the first 3 years. Hemorrhage clustering within 3 years was statistically significant (HR 6.1, 95% CI 1.72-21.7, p = 0.005). On multivariate analysis, hemorrhagic presentation (HR 4.63, 95% CI 1.53-14.1, p = 0.007), brainstem location (HR 4.42, 95% CI 1.57-12.4, p = 0.005), and an associated radiologically apparent DVA (HR 2.91, 95% CI 1.04-8.09, p = 0.04) emerged as significant risk factors for hemorrhage, whereas age, sex, CM multiplicity, and CM family history did not. CONCLUSIONS Prior hemorrhage, brainstem location, and associated DVAs are significant risk factors for symptomatic hemorrhage in children with CMs. Hemorrhage clustering within the first 3 years of a bleed can occur, a potentially important factor in patient management and counseling.

Angiographically occult vascular malformation of the intracranial accessory nerve: case report.

Angiographically occult cerebral vascular malformations (AOVMs) are usually found in the supratentorial brain parenchyma. Uncommonly, AOVMs can be found within the cavernous sinus or basal cisterns and can be associated with cranial nerves. AOVMs involving the intracranial segment of the spinal accessory nerve have not been described. A 46-year-old female patient presented with a history of episodic frontal headaches and episodes of nausea and dizziness, as well as gait instability progressing over 6 months prior to evaluation. Imaging revealed a well-circumscribed 3-cm extraaxial T1-weighted isointense and T2-weighted hyperintense contrast-enhancing mass centered in the region of the right lateral cerebellomedullary cistern. The patient underwent resection of the lesion. Although the intraoperative appearance was suggestive of a cavernous malformation, some histological findings were atypical, leading to the final diagnosis of vascular malformation, not otherwise specified. The patient's postoperative course was uneventful with complete resolution of symptoms. To the authors' knowledge, this is the first report of an AOVM involving the intracranial portion of the accessory nerve. For any AOVM located within the cerebellomedullary cistern or one suspected of involving a cranial nerve, the authors recommend including immunohistochemistry with primary antibody to neurofilament in the histopathology workup.

Symptomatic large or giant capillary telangiectasias: management and outcome in 5 cases.

Brain capillary telangiectasias (BCTs) are usually small and benign with a predilection in the pons and basal ganglion. Reports of large and symptomatic BCTs are rare. Large BCTs have a much higher risk of causing uncontrolled bleeding and severe neurological defects, and they can be fatal if left untreated. Therefore, large BCTs should be managed with special caution. Because of the lack of reports, diagnosis of large BCTs has been difficult. Strategies of management are undefined for large or giant BCTs. The current study presents 5 cases of giant and large BCTs. To the authors' knowledge, this is the largest series of this disease ever reported. Radiological findings, histopathological characteristics, clinical presentations, and surgical management were analyzed in 5 symptomatic, unusually large BCTs (mean diameter 5.06 cm, range 1.8-8 cm). Four patients presented with focal or generalized seizures, and 1 patient presented with transient vision loss attributed to the lesions. Gross-total resection of the lesion was achieved in all patients. After surgery, the 4 patients with seizures were symptom free for follow-up periods varying from more than 1 to 5 years with no additional neurological deficits. The unique location, radiological characteristics, and clinical course suggest that giant BCTs could be a different entity from small BCTs. Surgery might be a good option for treatment of patients with intractable neurological symptoms, especially in those with surgically accessible locations. Complete removal would be anticipated to provide relief of the symptoms without causing new neurological deficits.