Tag: cavernous malformation

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Prospective untreated outcomes in patients with cerebral cavernous malformation

J Neurosurg 144:1344–1352, 2026

This prospective cohort study quantifies long-term functional outcomes in 332 untreated patients with cerebral cavernous malformation (CCM), using modified Rankin Scale (mRS) scores to evaluate disability over a mean 6.6-year follow-up. It reports incidence of symptomatic hemorrhage (SH), temporal patterns of recovery after a first SH, and external validation of published predictive nomograms.

Key findings identify brainstem location, a history of self-reported psychiatric disorder, and two or more SHs as independent predictors of long-term disability; most patients improved within one year after a first hemorrhage, and ten-year disability risk for nonbrainstem CCM was under 8%.

Objective Elucidate long-term morbidity and disability risk in adults with untreated cerebral cavernous malformation (CCM).

Methods Prospectively followed registry cohort; functional outcome tracked using mRS, with disability defined as mRS ≥ 3; time-to-disability analyzed via Kaplan–Meier and risk factors via Cox models; previously published morbidity nomograms were externally validated.

Cohort 332 patients (58.4% female; mean age 44.5); 19.8% familial CCM; 28.0% brainstem location; 38.3% presented with symptomatic hemorrhage (SH).

Recovery after first SH Among patients with SH who had no further SH and no surgery (n=48), disability (mRS ≥ 3) was 27.1% at diagnosis, improving to 6.2% at 1 year and 4.7% at 5 years, with most improvement in year 1.

Hemorrhage burden Over mean 6.6 years, 31.0% had ≥1 prospective SH and 14.5% had multiple prospective SHs; disability rose sharply with each SH (mRS ≥ 3: 2.3% with 0 SH up to 100% after 5 SHs in untreated follow-up).

Location risk Brainstem CCM carried substantially higher disability risk (18.8% at 5 years; 35.4% at 10 years) versus nonbrainstem locations (4.1% at 5 years; 7.5% at 10 years).

Predictors Multivariate predictors of disability included brainstem location, self-reported psychiatric disorder, and ≥2 SHs.

Nomogram validation Prior nomograms showed high specificity but limited sensitivity; AUC 0.687 for predicting mRS ≥ 2 and 0.783 for predicting mRS ≥ 3.

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Natural History of Sporadic Cerebral Cavernous Malformations by Zabramski Classification: Hemorrhage Risk and Functional Outcomes Over 5 Years

Neurosurgery 98:376–383, 2026

This prospective cohort study examines sporadic cerebral cavernous malformations (CCMs) categorized by Zabramski MRI types I–IV, reporting lesion features, presentation, hemorrhage rates, and mRS outcomes over a mean follow-up of 4.7 years. Type I lesions had the highest symptomatic presentation, largest size, brainstem predominance, and elevated hemorrhage risks.

Functional outcomes improved for some patients, but Type I had the poorest outcomes. Severe symptomatic hemorrhage was the strongest predictor of sustained disability (mRS ≥3). Types III and IV had low hemorrhage rates and favorable prognoses, supporting conservative management and tailored follow-up imaging.

Zabramski Classification: Stratifies cerebral cavernous malformations (CCMs) into Types I–IV based on MRI features, which correlate with clinical presentation, hemorrhage risk, and functional outcomes.

Type I Lesions: Show the highest annual symptomatic hemorrhage (SH) rate (13.9%), a 5-year cumulative risk of 50.6%, are mostly symptomatic at presentation, often located in the brainstem, and have the poorest long-term functional outcomes (mRS ≥2 in 35.4% at last follow-up).

Type II and III Lesions: Exhibit lower annual hemorrhage rates (2.9% and 1.8%, respectively), more frequently present with seizures or focal neurological deficits rather than hemorrhage, and have better long-term functional outcomes (Type II: mRS ≥2 in 11.2%; Type III: mRS ≥2 in 7.5% at last follow-up).

Type IV Lesions: Are exclusively asymptomatic, detected incidentally, have no observed hemorrhagic events during follow-up, and show no functional impairment (no cases of mRS ≥2).

Severe Symptomatic Hemorrhage: Is the strongest independent predictor of poor functional outcome (mRS ≥3), outweighing lesion type, age, location, or surgical intervention in multivariate analysis (HR 10.88, P < .001).

Dynamic Lesion Evolution: Zabramski type can change over time, particularly for Type I lesions, highlighting the need for longitudinal imaging and dynamic risk assessment rather than reliance on a single timepoint classification.

Clinical Management Implications: Conservative management is appropriate for most Type III and IV lesions due to their benign natural history, while Type I lesions require closer monitoring and individualized intervention strategies due to higher risk.

Study Limitations: Small sample sizes for Types III and IV, potential MRI protocol variability, and single-center design may limit generalizability; multicenter studies are needed for broader validation.

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Optimal imaging follow-up strategies for conservatively managed cerebral cavernous malformations: a cost-effectiveness analysis

J Neurosurg 143:1555–1566, 2025

This study evaluates cost-effectiveness of MRI surveillance intervals for conservatively managed cerebral cavernous malformations (CCMs) using a Markov model and Monte Carlo simulations. It compares 0.5-, 1-, 2-, and 3-year follow-up strategies for brainstem versus nonbrainstem CCMs, calculating lifetime costs, QALYs, and net monetary benefit from a US societal perspective.

Results indicate annual MRI is most cost-effective for brainstem CCMs, while a 3-year MRI interval is preferred for nonbrainstem CCMs, with findings robust to sensitivity analyses that varied hemorrhage rates, mortality, and MRI costs. The authors emphasize individualized follow-up based on symptoms, Zabramski grade, family history, and lesion multiplicity, and note model limitations and US-centric cost data.

Optimal MRI Follow-up for Brainstem CCM: Annual MRI follow-up (every 1 year) is the most cost-effective strategy for conservatively managed, unruptured brainstem cerebral cavernous malformations (CCM), balancing cost and quality-adjusted life years (QALYs).

Optimal MRI Follow-up for Nonbrainstem CCM: MRI follow-up every 3 years is the most cost-effective approach for nonbrainstem CCM, with less frequent imaging justified by lower rupture and rehemorrhage rates.

Markov Model and Monte Carlo Simulation: A decision-analytic Markov model with Monte Carlo simulations was used to compare different MRI follow-up intervals (0.5, 1, 2, and 3 years) for both brainstem and nonbrainstem CCM, incorporating costs, effectiveness (QALYs), and net monetary benefit (NMB).

Key Drivers of Cost-effectiveness: The cost-effectiveness of follow-up strategies is highly sensitive to annual rates of CCM rupture, mortality after rupture, and the cost of MRI; higher hemorrhage or mortality rates favor more frequent imaging.

Individualization of Follow-up: Follow-up intervals should be tailored based on lesion location, symptoms, prior hemorrhage, Zabramski grade, family history, and multiplicity, as higher-risk patients may benefit from closer surveillance.

Brainstem Lesion Risks: Brainstem CCMs have higher annual rupture (2.8%) and rehemorrhage rates (32.3%) compared to nonbrainstem lesions, resulting in greater disability and loss of quality of life, justifying more vigilant follow-up.

MRI Cost Thresholds: As the annual MRI cost increases above $6,581 for brainstem CCM and $8,995 for nonbrainstem CCM, less frequent MRI follow-up (every 2 years) becomes more cost-effective than the previously optimal intervals.

Limitations: The model does not distinguish between cerebellar and supratentorial nonbrainstem lesions, does not account for comorbidities or detailed imaging findings (e.g., Zabramski grade), and uses US-based cost data, which may limit generalizability to other healthcare settings.

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Clinical and radiological presentation of cavernomas according to the Zabramski classification

J Neurosurg 142:1751–1762, 2025

Most cerebral cavernous malformations (CCMs) are asymptomatic, especially Zabramski type IV. Symptoms, mainly seizures or neurological deficits, are primarily linked to Zabramski type I. Type I CCMs often regress to types II/III, but up to one-quarter develop new symptoms over time.

• Most cerebral cavernous malformations (CCMs) are asymptomatic and found incidentally on MRI.

• Zabramski classification is widely used to describe CCMs’ radiological features, but its correlation with clinical symptoms was not well established before this study.

• Zabramski type I CCMs are mostly symptomatic and associated with an unstable clinical course; types II and III are usually asymptomatic or have mild symptoms; type IV CCMs are always asymptomatic.

• Epileptic seizures are the most common presenting symptom, especially for supratentorial CCMs; infratentorial CCMs more often cause balance problems and cranial nerve deficits.

• Most Zabramski type I CCMs regress over time to type II or III; very few type II or III CCMs change to type I.

• Age is associated with Zabramski type: type I CCMs occur in younger patients, type III in older.

• Nearly all Zabramski type IV CCMs appear in patients with multiple CCMs and remain stable and asymptomatic over time.

• The Zabramski type at diagnosis can help predict the future clinical course of CCMs.

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Natural history, management, and outcomes of cerebellar cavernous malformations: A retrospective study of 130 patients

Neurosurgical Review (2025) 48:381

This study on cerebellar cavernous malformations (CMs) examines their natural history, management, and outcomes. It concludes that conservative management is generally effective for incidental lesions, while surgery is recommended for symptomatic cases, especially in accessible regions, due to the associated hemorrhage risks.

• This study investigates cerebellar cavernous malformations (CMs), focusing on natural history, management, and outcomes in 130 patients from 1990 to 2023.

• Hemorrhage risk for incidental lesions is 1.19%, while rehemorrhage risk for initially hemorrhagic lesions is 8.35%.

• Conservative management is recommended for incidental lesions, with surgery reserved for symptomatic, accessible cases.

• Surgery was performed on 31 patients, primarily for hemorrhage or cerebellar symptoms, with postoperative complications in three patients.

• Lesion location and size significantly influence hemorrhage risk and clinical outcomes, with eloquent regions posing higher risks.

• Long-term outcomes were generally favorable, with most patients experiencing improved or stable functional status.

• Psychological support is important due to potential cognitive and emotional impacts associated with cerebellar dysfunction.

• The study emphasizes the need for risk stratification based on lesion size and subregional anatomy within the cerebellum.

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Laser interstitial thermal therapy for cavernous malformations: a meta-analysis of individual patient-level data

J Neurosurg 142:1014–1024, 2025

Laser interstitial thermal therapy (LITT) shows promise for treating cavernous malformations, offering high seizure freedom rates and significant CM volume reduction. Immediate neurological deficits are a risk but often transient. Further research is needed for long-term outcomes and safety validation.

• Study Objective: Evaluate laser interstitial thermal therapy (LITT) for cavernous malformations (CMs).

• Methodology: PRISMA-compliant systematic review and patient-level data meta-analysis.

• Patient Demographics: 39 patients, 28 with epilepsy, treated at six centers.

• Seizure Freedom Rate: 88% at last follow-up for epilepsy patients.

• Immediate Postoperative Deficits: 15.4% experienced transient neurological deficits.

• CM Volume Reduction: 73.7% for epileptogenic, 53.8% for nonepileptogenic CMs.

• No Perioperative Hemorrhage: No reported hemorrhages during or after procedures.

• Study Limitations: Small patient cohort, limited follow-up time.

• Predictors of Seizure Freedom: No significant predictors identified.

• Adverse Events Analysis: No significant predictors for adverse events post-LITT.

• Radiographic Outcomes: No significant differences based on CM location.

• Pooled Effect Size Analysis: Frequentist and Bayesian models used for volume reduction estimates.

• Future Research Needs: Larger cohorts and longer follow-up required for validation.

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Contemporary cohort of cerebral cavernous malformations: natural history and utility of follow-up MRI

J Neurosurg 141:1159–1167, 2024

This study reports the natural history of cerebral cavernous malformations (CCMs) in a contemporary cohort with prospectively collected data from multiple sources, access to follow-up imaging, integrated electronic medical records, and detailed imaging review by study investigators. The authors aimed to define the first prospective symptomatic hemorrhage (SH) and severe SH rates, determine the risk of a second prospective SH, and identify risk factors for SH.

METHODS From a prospectively maintained database of adult patients with radiologically defined CCM, those with radiation-induced CCM, those who underwent surgery within 3 months postdiagnosis, and those with < 1 year of followup were excluded. The patients’ medical history and radiological features of the CCM were recorded at the time of diagnosis. Follow-up annual written surveys were completed for 5 years after the initial diagnosis and then semiannually thereafter in addition to medical record and follow-up imaging review. Outcomes of interest included SH and severe SH.

RESULTS Of 315 patients, 58.7% were female and 19.7% had familial CCMs. At diagnosis, 37.1% of patients had ruptured CCMs and 28.9% of the CCMs were located in the brainstem. The 5-year cumulative rates of prospective SH and severe SH in those with ruptured CCMs at diagnosis were 41.2% and 12.8%, respectively, compared with 6.1% and 2.5% in patients with unruptured CCMs at diagnosis (p < 0.0001). Risk factors for prospective SH included a ruptured CCM at diagnosis and persistent or new hyperintensity on T1-weighted MRI performed > 3 months after baseline MRI. For those with a ruptured CCM at diagnosis, the risk of developing a second prospective SH was similar to that of developing a first SH.

CONCLUSIONS In a contemporary cohort of adult patients with CCM, the authors report 5-year SH and severe SH rates, rates of second prospective hemorrhage, and predictors of SH. Persistent or new hyperintensity on T1-weighted MRI may be a useful marker of disease activity.

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One-Point Technique in Brainstem Cavernous Malformation Surgery

Operative Neurosurgery 27:557–565, 2024

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.

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Microsurgical Resection of Brainstem Cavernous Malformations in Older Adults: A Multicenter, 30-Year Experience

Neurosurgery 95:669–675, 2024

Microsurgical resection is the only curative intervention for symptomatic brainstem cavernous malformations (BSCMs), but the management of these lesions in older adults (≥65 years) is not well described. This study sought to address this gap by examining the safety and efficacy of BSCM resection in a cohort of older adults.

METHODS: Records of patients who underwent BSCM resection over a 30-year period were reviewed retrospectively. Baseline characteristics and outcomes were compared between older (≥65 years) and younger (<65 years) patients.

RESULTS: Of 550 patients with BSCM who met inclusion criteria, 41 (7.5%) were older than 65 years. Midbrain (43.9% vs 26.1%) and medullary lesions (19.5% vs 13.6%) were more common in the older cohort than in the younger cohort (P = .01). Components of the Lawton BSCM grading system (ie, lesion size, crossing axial midpoint, developmental venous anomaly, and timing of hemorrhage) were not significantly different between cohorts (P ≥ .11). Mean (SD) Elixhauser comorbidity score was significantly higher in older patients (1.86 [1.06]) than in younger patients (0.66 [0.95]; P < .001). Older patients were significantly more likely than younger patients to have poor outcomes at final follow-up (28.9% vs 13.8%, P = .01; mean follow-up duration, 28.7 [39.1] months). However, regarding relative neurological outcome (preoperative modified Rankin Scale to final modified Rankin Scale), rate of worsening was not significantly different between older and younger patients (23.7% vs 14.9%, P = .15).

CONCLUSION: BSCMs can be safely resected in older patients, and when each patient’s unique health status and life expectancy are taken into account, these patients can have outcomes similar to younger patients.

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Eloquent noneloquence: redefinition of cortical eloquence based on outcomes of superficial cerebral cavernous malformation resection

J Neurosurg 141:291–305, 2024

Cerebral cavernous malformations (CMs) are pathological lesions that cause discrete cortical disruption with hemorrhage, and their transcortical resections can cause additional iatrogenic disruption. The analysis of microsurgically treated CMs might identify areas of “eloquent noneloquence,” or cortex that is associated with unexpected deficits when injured or transgressed.

METHODS Patients from a consecutive microsurgical series of superficial cerebral CMs who presented to the authors’ center over a 13-year period were retrospectively analyzed. Neurological outcomes were measured using the modified Rankin Scale (mRS), and new, permanent neurological or cognitive symptoms not detected by changes in mRS scores were measured as additional functional decline. Patients with multiple lesions and surgical encounters for different lesions within the study interval were represented within the cohort as multiple patient entries. Virtual object models for CMs and approach trajectories to subcortical lesions were merged into a template brain model for subtyping and Quicktome connectomic analyses. Parcellation outputs from the models were analyzed for regional cerebral clustering.

RESULTS Overall, 362 CMs were resected in 346 patients, and convexity subtypes were the most common (132/362, 36.5%). Relative to the preoperative mRS score, 327 of 362 cases (90.3%) were in patients who improved or remained stable, 35 (9.7%) were in patients whose conditions worsened, and 47 (13.0%) were in patients who had additional functional decline. Machine learning analyses of lesion objects and trajectory cylinder mapping identified 7 hotspots of novel eloquence: supplementary motor area (bilateral), anterior cingulate cortex (bilateral), posterior cingulate cortex (bilateral), anterior insula (left), frontal pole (right), mesial temporal lobe (left), and occipital cortex (right).

CONCLUSIONS Transgyral and transsulcal resections that circumvent areas of traditional eloquence and navigate areas of presumed noneloquence may nonetheless result in unfavorable outcomes, demonstrating that brain long considered by neurosurgeons to be noneloquent may be eloquent. Eloquent hotspots within multiple large-scale networks redefine the neurosurgical concept of eloquence and call for more refined dissection techniques that maximize transsulcal dissection, intracapsular resection, and tissue preservation. Human connectomics, awareness of brain networks, and prioritization of cognitive outcomes require that we update our concept of cortical eloquence and incorporate this information into our surgical strategies.

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A taxonomy for superficial cerebral cavernous malformations: subtypes of cortical and subcortical lesions

J Neurosurg 141:123–137, 2024

A taxonomy for superficial cerebral cavernous malformations (CMs), those based cortically in gyral gray matter or subcortically in underlying white matter, is proposed to build on the comprehensive, systematic characterization of CMs in the entire brain.

METHODS Patients with superficial cerebral CMs were retrospectively analyzed from a consecutive surgical series between November 2008 and June 2021 at the authors’ center. Superficial cerebral CMs were categorized into 4 subtypes based on their cortical location or, if subcortical, proximity to the nearest cerebral surface: convexity, medial, basal, and sylvian. Lobar location was also included for subtyping: frontal, temporal, parietal, and occipital.

RESULTS A total of 362 CMs were resected in 346 patients. CM subtypes were as follows: 132 (36.5%) convexity, 78 (21.5%) medial, 72 (19.9%) basal, and 80 (22.1%) sylvian. Frontal CMs were most common (155 [42.8%]), followed by parietal (89 [24.6%]), temporal (87 [24.0%]), and occipital (31 [8.6%]). Of all CMs, 302 (83.4%) were cortical and 60 (16.6%) were subcortical. The mean subcortical depth of deep lesions was 2.97 cm, and the mean lesion volume was 4.68 cm 3 . Overall, 228 lesions (63.0%) were resected through a transgyral approach, and 134 (37.0%) were resected through a transsulcal approach. Good outcomes (modified Rankin Scale [mRS] score ≤ 2) were observed in 314 patients (86.7%) and poor outcomes (mRS score > 2) in 25 patients (6.9%), and 23 patients (6.4%) were lost to late follow-up (mean follow-up duration 11.5 months). Relative outcomes were good (unchanged or improved mRS score) in 327 patients (90.3%) and poor (worse or died) in 35 patients (9.7%).

CONCLUSIONS Superficial cerebral CMs were resected through a gyrus or sulcus to open the subarachnoid dissection corridors, traversing the full extent of sulci to deepen the approach and minimize tissue transgression. Transgyral dissection avoids associated arteries but is inherently transgressive, whereas transsulcal dissection preserves cortical tissue and may reduce morbidity. Superficial cerebral CMs occupy the largest territory of the 7 types, and the size and surface complexity of the cerebrum make taxonomic subtyping valuable for clear anatomical description.

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Cavernous venous malformations in and around the central nervous system. Part 2: Intradural

J Neurosurg 140:746–754, 2024

Cavernous venous malformations (CavVMs) account for a spectrum of lesions with a shared pathogenesis. Their anatomical location dictates their clinical features and surgical treatment. Extradural and dura-based CavVMs were discussed in Part 1 of this review.

In this part, intradural CavVMs are discussed, encompassing malformations growing within the intradural space without direct dural involvement. In addition to classic intra-axial CavVMs, cranial nerve CavVMs, intraventricular CavVMs, and intradural extramedullary spinal CavVMs are discussed in this group, given the similar natural history and specific management challenges.

Herein the authors focus on critical clinical aspects of and surgical management of these malformations based on their location and discuss optimal surgical approaches at each of these anatomical locations with illustrative cases. The commonalities of the natural history and surgical management that are dictated by anatomical considerations lend to a new location-based taxonomy for classification of CavVMs.

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Cavernous venous malformations in and around the central nervous system. Part 1: Dural and extradural

J Neurosurg 140:735–745, 2024

Cavernous-type malformations are venous lesions that occur in multiple locations throughout the body, and when present in the CNS, they have canonically been referred to as cavernomas, cavernous angiomas, and cerebral cavernous malformations. Herein all these lesions are referred to as “cavernous venous malformations” (CavVMs), which is congruent with the current International Society for the Study of Vascular Anomalies classification system.

Even though histologically similar, depending on their location relative to the dura mater, these malformations can have different features. In Part 1 of this review, the authors discuss and review pertinent clinical knowledge with regard to CavVMs as influenced by anatomical location, starting with the dural and extradural malformations. They particularly emphasize dural CavVMs (including those in the cavernous sinus), orbital CavVMs, and spinal CavVMs. The genetic and histopathological features of CavVMs in these locations are reviewed, and commonalities in their presumed mechanisms of pathogenesis support the authors’ conceptualization of a spectrum of a single disease entity. Illustrative cases for each subtype are presented, and the pathophysiological and genetic features linking dural and extradural to intradural CavVMs are examined.

A new classification is proposed to segregate CavVMs based on the location from which they arise, which guides their natural history and treatment.

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Safety of brainstem safe entry zones: comparison of microsurgical outcomes associated with superficial, exophytic, and deep brainstem cavernous malformations

J Neurosurg 139:113–123, 2023

Safe entry zones (SEZs) enable safe tissue transgression to lesions beneath the brainstem surface. However, evidence for the safety of SEZs is scarce and is based on anatomical studies, case reports, and small series.

METHODS A cohort of 154 patients who underwent microsurgical brainstem cavernous malformation (BSCM) treatment during a 23-year period and who had preoperative MR images and intraoperative photographs or videos was retrospectively examined. This study assessed the safety of SEZs for access to deep BSCMs, preoperative MRI to predict BSCM surface proximity, and the relationships between BSCM subtype, surgical approach, and SEZs. Lesions were characterized as exophytic, superficial, or deep on the basis of preoperative MRI and intraoperative inspection. Outcomes were scored as good (modified Rankin Scale [mRS] score ≤ 2) or poor (mRS score > 2) and relative outcomes as stable/ improved or worse relative to baseline (± 1 point).

RESULTS Resections included 34 (22%) in the midbrain, 102 (66%) in the pons, and 18 (12%) in the medulla. Of those, 23 (15%) were exophytic, 57 (37%) were superficial, and 74 (48%) were deep. Established SEZs were used for 97% (n = 72) of deep lesions; the preferred SEZ associated with its subtype was used for 91% (n = 67). MR images accurately depicted exophytic BSCMs that did not require SEZ approaches (sensitivity, 96%) but overestimated the proximity of lesions superficial to brainstem surfaces (specificity, 67%), resulting in unanticipated SEZ use. Final neurological outcomes were good in 80% of patients with follow-up data (119/149), and relative outcomes were stable/improved in 93% (139/149). Outcomes for patients with brainstem transgression through an SEZ did not differ from outcomes for patients with superficial or exophytic lesions that did not require SEZ use (final mRS score ≤ 2 in 72% of all patients with deep lesions vs 82% of all patients with superficial or exophytic lesions [p = 0.10]). Among patients with follow-up, the rates of permanent new cranial nerve deficits in patients with deep BSCMs and superficial or exophytic BSCMs were 21% and 20%, respectively (p = 0.81), with no significant change in overall cranial nerve deficit (0 and −1, p = 0.65).

CONCLUSIONS Neurological outcomes for patients with deep BSCMs were equivalent to those for superficial or exophytic BSCMs, validating the safety of SEZs for deep BSCMs. Preoperative T1-weighted MR images overestimated the lesion’s surface proximity, necessitating detailed knowledge of SEZs and readiness to use them in cases of radiologicalmicrosurgical discordance. Most patients achieved favorable outcomes despite the transgression of eloquent brainstem tissue in and around SEZs.

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Presigmoid approach preserving the superior petrosal sinus in a pontine cavernous malformation associated to abnormal venous drainage of the brainstem

Acta Neurochirurgica (2023) 165:1233–1240

The presigmoid approach classically includes the ligature and section of the superior petrosal sinus to get a wider visibility window to the antero-lateral brainstem surface. In some cases, the separation of this venous structure should not be performed.

Method We present our experience getting safely to a pontine cavernous malformation through a conventional mastoidectomy presigmoid approach preserving an ingurgitated superior petrosal sinus because the association with an abnormal venous drainage of the brainstem.

Conclusions When sectioning the superior petrosal sinus in classical presigmoid approaches is contraindicated, its preservation could also offer good surgical corridors to get to small-medium anterior and lateral brainstem cavernous malformations.

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Endoscope‐assisted resection of brainstem cavernous malformations

Neurosurgical Review (2022) 45:2823–2836

Targeted surgical precision and minimally invasive techniques are of utmost importance for resectioning cavernous malformations involving the brainstem region. Minimisation of the surgical corridor is desirable but should not compromise the extent of resection.

This study provides detailed information on the role of endoscopy in this challenging surgical task. A retrospective analysis of medical documentation, radiologic studies and detailed intraoperative video documentation was performed for all consecutive patients who underwent surgical resection of brainstem cavernous malformations between 2010 and 2020 at the authors’ institution.

A case-based volumetry of the corticotomy was performed and compared to cavernoma dimensions. A total of 20 procedures have been performed in 19 patients. Neuroendoscopy was implemented in all cases. The mean size of the lesion was 5.4 (± 5) mm3. The average size of the brainstem corticotomy was 4.5 × 3.7 (± 1.0 × 1.1) mm, with a median relation to the cavernoma’s dimension of 9.99% (1.2–31.39%). Endoscopic 360° inspection of the resection cavity was feasible in all cases. There were no endoscopy-related complications. Mean follow-up was 27.8 (12–89) months.

Gross-total resection was achieved in all but one case (95%). Sixteen procedures (80%) resulted in an improved or stable medical condition. Eleven patients (61.1%) showed further improvement 12 months after the initial surgery. With the experience provided, endoscopic techniques can be safely implemented in surgery for BSCM. A combination of neuroendoscopic visualisation and neuronavigation might enable a targeted size of brainstem corticotomy.

Endoscopy can currently be considered a valuable additive tool to facilitate the preparation and resection of BSCM.

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A taxonomy for brainstem cavernous malformations: subtypes of midbrain lesions

J Neurosurg 136:1667–1686, 2022

Anatomical taxonomy is a practical tool that has successfully guided clinical decision-making for patients with brain arteriovenous malformations. Brainstem cavernous malformations (BSCMs) are similarly complex lesions that are difficult to access and highly variable in size, shape, and position. The authors propose a novel taxonomy for midbrain cavernous malformations based on clinical presentation (syndromes) and anatomical location (identified with MRI).

METHODS The taxonomy system was developed and applied to an extensive 2-surgeon experience over a 30-year period (1990–2019). Of 551 patients with appropriate data who underwent microsurgical resection of BSCMs, 151 (27.4%) had midbrain lesions. These lesions were further subtyped on the basis of predominant surface presentation identified on preoperative MRI. Five distinct subtypes of midbrain BSCMs were defined: interpeduncular (7 lesions [4.6%]), peduncular (37 [24.5%]), tegmental (73 [48.3%]), quadrigeminal (27 [17.9%]), and periaqueductal (7 [4.6%]). Neurological outcomes were assessed using modified Rankin Scale (mRS) scores. A postoperative score ≤ 2 was defined as a favorable outcome; a score > 2 was defined as a poor outcome. Clinical and surgical characteristics and neurological outcomes were compared among subtypes.

RESULTS Each midbrain BSCM subtype was associated with a recognizable constellation of neurological symptoms. Patients with interpeduncular lesions commonly presented with ipsilateral oculomotor nerve palsy and contralateral cerebellar ataxia or dyscoordination. Peduncular lesions were associated with contralateral hemiparesis and ipsilateral oculomotor nerve palsy. Patients with tegmental lesions were the most likely to present with contralateral sensory deficits, whereas those with quadrigeminal lesions commonly presented with the features of Parinaud syndrome. Periaqueductal lesions were the most likely to cause obstructive hydrocephalus. A single surgical approach was preferred (> 90% of cases) for each midbrain subtype: interpeduncular (transsylvian-interpeduncular approach [7/7 lesions]), peduncular (transsylvian-transpeduncular [24/37]), tegmental (lateral supracerebellar-infratentorial [73/73]), quadrigeminal (midline or paramedian supracerebellar-infratentorial [27/27]), and periaqueductal (transcallosal-transchoroidal fissure [6/7]). Favorable outcomes (mRS score ≤ 2) were observed in most patients (110/136 [80.9%]) with follow-up data. No significant differences in outcomes were observed between subtypes (p = 0.92).

CONCLUSIONS The study confirmed the authors’ hypothesis that taxonomy for midbrain BSCMs can meaningfully guide the selection of surgical approach and resection strategy. The proposed taxonomy can increase diagnostic acumen at the patient bedside, help identify optimal surgical approaches, enhance the consistency of clinical communications and publications, and improve patient outcomes.

 

 

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Anatomo‑functional evaluation for management and surgical treatment of insular cavernous malformation: a case series

Acta Neurochirurgica (2022) 164:1675–1684

Insular cavernous malformations (iCMs) are very rare vascular lesions. Their surgical management is chal- lenging, due to their complex functional and vascular relationship. The continuous improvement of intra-operative tools and neuroimaging techniques has progressively enhanced the safety of iCM surgery. Nevertheless, the best surgical approach remains controversial.

Objective To analyze the potential role of an anatomo-functional classification to guide the iCMs’ management.

Methods The study included patients affected by iCMs and referred to the Senior Author (FA). All cases were divided in 2 groups, according to a mainly pial growth pattern (exophytic group) or a subcortical one (endophytic group). Endophytic iCM was further subdivided in 3 subgroups, based on the insular gyri involved. According to this classification, each patient underwent a specific additional neuroimaging investigation and surgical evaluation.

Results A total of 24 patients were included. In the surgical group, trans-sylvian (TS) approach was used in 6 patients with exophytic or Zone I endophytic iCMs. The transcortical (TC) approach with awake monitoring was used in 6 cases of Zone II endophytic vascular lesions. Both TS and trans-intraparietal sulcal (TIS) approach were used for 3 cases of Zone III endophytic iCM. At follow-up, 3 patients were fully recovered from a transient speech impairment while a permanent morbidity was observed in one case.

Conclusions ICMs represent a single entity with peculiar clinical and surgical aspects. The proposed iCM classification focuses on anatomical and functional concerns, aiming to suggest the best pre-operative work-up and the surgical evaluation.

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How I do it: horizontal fissure approach to the middle cerebellar peduncle

Acta Neurochirurgica (2022) 164:763–766

The horizontal fissure approach is a workhorse for brainstem lesions in the central and dorsolateral pons and middle cerebellar peduncle (MCP). The cerebellopontine fissure is a V-shaped fissure with a superior and inferior limb between the cerebellum, pons, and MCP. The horizontal or petrosal fissure is at the apex of the cerebellopontine fissure and extends laterally to divide the petrosal surface of the cerebellum into superior and inferior parts. Splitting this fissure exposes the posterolateral aspect of the MCP without excessive retraction or transgression of the cerebellum.

Method We demonstrate and describe the horizontal fissure operative approach to the middle cerebellar peduncle for resection of a pontine cavernoma with illustrative figures and operative video.

Conclusion Splitting the horizontal (petrosal) fissure of the cerebellum brings the middle cerebellar peduncle into view behind the root entry zone of the trigeminal nerve, providing an expanded, safe corridor to the central and dorsolateral pons.

 

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Basal ganglia cavernous malformations: case series and systematic review of surgical management and long-term outcomes

J Neurosurg 135:1113–1121, 2021

Reports on basal ganglia cavernous malformations (BGCMs) are rare. Here, the authors report on their experience in resecting these malformations to offer insight into this infrequent disease subtype.

METHODS The authors retrospectively reviewed a prospectively managed departmental database of all deep-seated cerebral cavernous malformations (CCMs) treated at Stanford between 1987 and 2019 and included for further analysis those with a radiographic diagnosis of BGCM. Moreover, a systematic literature review was undertaken using the PubMed and Web of Science databases.

RESULTS The departmental database search yielded 331 patients with deep-seated CCMs, 44 of whom had a BGCM (13.3%). Headache was the most common presenting sign (53.5%), followed by seizure (32.6%) and hemiparesis (27.9%). Lesion location involved the caudate nucleus in 21.4% of cases compared to 78.6% of cases within the lentiform nucleus. Caudate BGCMs were larger on presentation and were more likely to present to the ependymal surface (p < 0.001) with intraventricular hemorrhage and hydrocephalus (p = 0.005 and 0.007, respectively). Dizziness and diplopia were also more common with lesions involving the caudate. Because of their anatomical location, caudate BGCMs were preferentially treated via an interhemispheric approach and were less likely to be associated with worsening perioperative deficits than lentiform BGCMs (p = 0.006 and 0.045, respectively). Ten patients (25.6%) were clinically worse in the immediate postoperative period, 4 (10.2%) of whom continued to suffer permanent morbidity at the last follow-up. A longterm good outcome (modified Rankin Scale [mRS] score 0–1) was attained in 74.4% of cases compared to the 69.2% of patients who had presented with an mRS score 0–1. Relative to their presenting mRS score, 89.8% of patients had an improved or unchanged status at the last follow-up. The median postoperative follow-up was 11 months (range 1–252 months). Patient outcomes after resection did not differ among surgical approaches; however, patients presenting with hemiparesis and lesions involving the globus pallidus or posterior limb of the internal capsule were more likely to suffer neurological deficits during the immediate perioperative period. Patients who had undergone awake surgeries were more likely to suffer neurological decline at the early as well as the late follow-up. When adjusting for awake craniotomy as a potential confounder of lesion location, a BGCM involving the posterior limb was predictive of developing early postoperative deficits, but this finding did not persist at the long-term follow-up.

CONCLUSIONS Surgery is a safe and effective treatment modality for managing BGCMs, with an estimated long-term permanent morbidity rate of around 10%.

 

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