Surgical Approaches for Symptomatic Cerebral Cavernous Malformations of the Thalamus and Brainstem

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

BACKGROUND AND OBJECTIVES

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.

Identifying potential (re)hemorrhage among sporadic cerebral cavernous malformations using machine learning

The (re)hemorrhage in patients with sporadic cerebral cavernous malformations (CCM) was the primary aim for CCM management. However, accurately identifying the potential (re)hemorrhage among sporadic CCM patients in advance remains a challenge. This study aims to develop machine learning models to detect potential (re)hemorrhage in sporadic CCM patients. This study was based on a dataset of 731 sporadic CCM patients in open data platform Dryad. Sporadic CCM patients were followed up 5 years from January 2003 to December 2018. Support vector machine (SVM), stacked generalization, and extreme gradient boosting (XGBoost) were used to construct models. The performance of models was evaluated by area under receiver operating characteristic curves (AUROC), area under the precision-recall curve (PR-AUC) and other metrics. A total of 517 patients with sporadic CCM were included (330 female [63.8%], mean [SD] age at diagnosis, 42.1 [15.5] years). 76 (re)hemorrhage (14.7%) occurred during follow-up. Among 3 machine learning models, XGBoost model yielded the highest mean (SD) AUROC (0.87 [0.06]) in cross-validation. The top 4 features of XGBoost model were ranked with SHAP (SHapley Additive exPlanations). All-Elements XGBoost model achieved an AUROCs of 0.84 and PR-AUC of 0.49 in testing set, with a sensitivity of 0.86 and a specificity of 0.76. Importantly, 4-Elements XGBoost model developed using top 4 features got a AUROCs of 0.83 and PR-AUC of 0.40, a sensitivity of 0.79, and a specificity of 0.72 in testing set. Two machine learning-based models achieved accurate performance in identifying potential (re)hemorrhages within 5 years in sporadic CCM patients. These models may provide insights for clinical decision-making.

Deep Ganglionic Intracerebral Hemorrhage Due to Cavernous Malformation Mimicking Hypertensive Hemorrhage: A Report of Two Cases

Cavernous malformation (CM) is a type of vascular malformation that is an important cause of intracerebral hemorrhage. However, because CM is a low-flow vascular malformation, the occurrence of major hemorrhage is rare. We present two patients with deep ganglionic intracerebral hemorrhage that caused a significant mass effect, mimicking hypertensive hemorrhage. In both cases, we performed evacuation of the hematoma as a lifesaving treatment and made a pathological diagnosis of CM. In conclusion, preoperative diagnosis of CM using any kind of radiological evaluation is difficult, especially in patients with major hemorrhage. The possibility of CM should be remembered in cases with deep ganglionic intracerebral hemorrhage.

A Case of Cavernous Malformation of the Midbrain Removed via an Interhemispheric Transcallosal Subchoroidal Approach

Cavernous malformations of the midbrain have a higher rate of hemorrhage and a poorer prognosis than vascular malformations of other brain areas. Surgical resection of these lesions is often necessary to avoid neurological deficits in affected patients. Herein, the literature surrounding cavernous malformations was examined, and the case of a 48-year-old man with left hemiparesis and diplopia caused by incomplete right oculomotor nerve palsy, who was diagnosed with a hemorrhage from a midbrain cavernous malformation, was discussed. The lesion expanded gradually on magnetic resonance imaging and was symptomatic; radical removal of the lesion before the onset of irreversible symptoms due to recurring bleeding was therefore considered to be beneficial for the patient. Surgical removal of the entire cavernous malformations of the midbrain was performed using an interhemispheric transcallosal subchoroidal approach, with excellent postoperative results and complete recovery from the oculomotor nerve palsy and left hemiparesis. This case shows that this approach is the most appropriate for surgical resections of lesions in the upper midbrain.

External validation of the Lawton brainstem cavernous malformation grading system in a cohort of 277 microsurgical patients

OBJECTIVE

The brainstem cavernous malformation (BSCM) grading system predicts neurological outcomes associated with microsurgical resection and assists neurosurgeons in selecting patients for treatment. The predictive accuracy of the BSCM grading system should be validated in a large cohort from high-volume centers to generalize its use.

METHODS

An external validation cohort comprised patients with a BSCM resected by the senior author (M.T.L.) since the publication of the BSCM grading system and those resected by another neurosurgeon (R.F.S.) over a 16-year period. Size, crossing the axial midpoint, the presence of a developmental venous anomaly, patient age, and timing of last hemorrhage were used to assign BSCM grades from 0 to VII. Poor neurological outcomes were recorded as modified Rankin Scale scores > 2 at last follow-up examination.

RESULTS

A total of 277 patients were included in the study. The average BSCM grade was 3.9, and the majority of BSCMs (181 patients, 65%) were intermediate grade (grades III-V). Outcomes were predicted by BSCM grade, with good outcomes observed in 47 of 54 patients (87%) with low-grade BSCMs, in 135 of 181 patients (75%) with intermediate-grade BSCMs, and in 21 of 42 patients (50%) with high-grade BSCMs. Conversely, proportions of patients with neurological deterioration increased with increasing BSCM grade, with worsening observed in 2 of 54 patients (4%) with low-grade BSCMs, in 29 of 181 patients (16%) with intermediate-grade BSCMs, and in 17 of 42 patients (40%) with high-grade BSCMs. In the chi-square analysis, high-grade BSCMs were associated with increased odds of neurological worsening compared to low- and intermediate-grade BSCMs (OR 5.0, 95% CI 2.4-10.4; p < 0.001). The receiver operating characteristic analysis demonstrated acceptable discrimination for predicting unfavorable functional outcomes (modified Rankin Scale score > 2) with an area under the curve of 0.74 (95% CI 0.68-0.80; p < 0.001).

CONCLUSIONS

This study validates the BSCM grading system in a large cohort of patients from two high-volume surgeons. BSCM grade predicted neurological outcomes with accuracy comparable to that of other grading systems in widespread use. The BSCM grading system establishes categories of low-, intermediate-, and high-grade BSCMs and a boundary or cutoff for surgery at BSCM grade V. BSCM grading guides the analysis of a particular patient's condition, but treatment recommendations must be individualized, and neurosurgeons must calibrate BSCM grading to their own outcome results, unique abilities, and practices.

A taxonomy for brainstem cavernous malformations: subtypes of midbrain lesions

OBJECTIVE

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.

Cerebral cavernous malformation remnants after surgery: a single-center series with long-term bleeding risk analysis

The aim of this work is to investigate the long-term bleeding risk of cerebral cavernous malformation (CCM) remnants. A review of clinical, radiological, operative, and post-operative data of a cerebral cavernous malformation (CCMs) prospective database was performed. Fisher’s exact test and Mann-Whitney U-test were used to assess differences between non-hemorrhagic and hemorrhagic CCM remnants for 14 variables. Recursive partitioning analysis was performed to assess the order of variables most associated with CCM remnant bleeding. Twenty-four patients out of 126 had a CCM post-surgical remnant. Of these, 7 had at least one post-operative hemorrhagic event. The mean follow-up was 80.7 months (range 12–144). CCM post-surgical remnant bleeding presented mostly with acute headache (50%) and focal neurological deficit (25%); in the remaining cases, the hemorrhage was asymptomatic. Retreatment was performed in two patients, with surgery and radiosurgery, respectively; no treatment was performed in the majority of cases. All patients ranked as non-II, according to Zabramski classification, did not show any post-surgical bleeding. The presence of a pre-operative perilesional hemosiderin ring was highly significant in predicting post-surgical bleeding (sensitivity = 0.94, specificity = 0.88) and incorrectly predicted bleeding in only two of the 24 patients. This study provides an evaluation of clinical and radiological factors influencing the bleeding risk of a CCM post-surgical remnant in a homogeneous population. Perilesional hemosiderin ring and Zabramski Type II appear to strongly condition the bleeding risk of a CCM post-surgical remnant.

Outcomes of basal ganglia and thalamic cavernous malformation surgery: A meta-analysis

Surgical resection of basal ganglia (BG) and thalamic cavernous malformations (CMs) has not yet become standardized in the field of neurosurgery due to the eloquent location of these lesions and the relative paucity of literature on the subject. This review presents a consolidation of the available literature on outcomes and complication rates after surgical resection of these lesions. A systematic literature review was performed via PubMed database for articles published between 1985 and 2019. Studies comprising ≥2 patients receiving surgery for BG or thalamic CMs with available follow-up data were included. Pooled data included patient demographics, CM preoperative characteristics, and surgical outcomes Twenty studies comprising 227 patients were included for analysis. Complete resection was achieved in 94.7% (fixed-effects pooled estimate [FE]: 94.9%[91.0%-97.8%]; random-effects pooled estimate [RE]: 90.0%[79.8%-96.9%]), and hemorrhage of incompletely resected CMs occurred in 50% (FE: 55.9%[25.9%-83.6%]; RE: 55.9%[25.9%-83.6%]) of patients. Early morbidity was observed in 24.0% (FE: 24.9%[17.8%-32.6%]; RE: 24.9%[17.8%-32.6%]). At final follow-up, 67.3% (FE: 67.7%[58.8%-76.0%]; RE: 67.8%[52.2%-81.6%]) and 20.6% (FE: 20.6%[13.6%-28.6%]; RE: 20.9%[9.8%-34.9%]) had improvement and stability of preoperative symptoms, respectively. Mortality rate was 1.3% (FE: 2.3%[0.6%-5.1%]; RE: 2.3%[0.6%-5.1%]). Therefore, high cure rates with low rates of postoperative morbidity can be achieved in BG or thalamic CM surgery. Most patients had improved neurological function at final follow-up. Complete resection should be attempted to reduce rates of repeat hemorrhage.

Surgical Management of Brain Cavernous Malformations

Surgical removal of accessible lesions is the only direct therapeutic approach for cerebral cavernous malformations (CCMs). The approach should be carefully evaluated according to clinical, anatomical, and neuroradiological assessment in order to both select the patient and avoid complications. In selected cases, a quantitative anatomical study with a preoperative simulation of surgery could be used to plan the operation. Neuronavigation, ultrasound, and neurophysiologic monitoring are generally required respectively to locate the CCMs and to avoid critical areas. The chapter describes all the possible surgical approaches for supratentorial, infratentorial, deep seated and brain stem CCMs. In any case before performing surgery, the physicians should always consider the benign nature of the lesions and the absolute necessity to avoid not only neurological deficits, but also a neuropsychological impairment that could affect the quality of life of the patients.

Posterolateral route for a midbrain cavernous malformation reaching the anterior surface of the brainstem

Cavernous malformations in the midbrain can be accessed via several safe entry zones. The accepted rule of thumb is to enter at the point where the lesion is visible at the surface of the brainstem to pass through as little normal brain tissue as possible. However, in some cases, in order to avoid critical neural structures, this rule may not apply. A different safe entry zone can be chosen. Our video presents a case of a ruptured cavernous malformation in the midbrain reaching its anterior surface which was successfully resected via a posterolateral route using the supracerebellar infratentorial approach. The video can be found here: https://youtu.be/7kt-OQuBmz0.

Long-Term Outcome of Gamma Knife Radiosurgery for Symptomatic Brainstem Cavernous Malformation

OBJECTIVE

We sought to analyze the long-term outcome of Gamma Knife radiosurgery (GKS) for symptomatic brainstem cavernous malformation (s-BSCM).

METHODS

Forty-five patients (14 males, 31 females) were treated with GKS for s-BSCM from January 1998 to December 2011. All patients were followed up for >5 years, and their clinical data were analyzed retrospectively. All patients had a history of symptomatic bleeding once or more before GKS. These hemorrhages caused neurologic deficits including cranial nerve deficits, hemiparesis, hemisensory deficits, spasticity, or chorea. The mean target volume of s-BSCM was 1.82 cm³, and the median prescribed marginal dose of radiation was 13 Gy. The mean clinical and imaging follow-up period was 9.31 years (range 5.1-19.4 years).

RESULTS

The 45 patients had 69 hemorrhagic events before GKS. During the follow-up period after GKS, 35 patients had no hemorrhagic event, 6 patients had 1 episode of symptomatic hemorrhage, and 4 patients had 2 episodes. The calculated annual hemorrhage rate was 40.06% at pre-GKS, 3.3% at 2 years after GKS, 1.48% at 5 years after GKS, and 4.64% at >5 years after GKS. In this study of 45 patients, symptomatic radiation-induced complications developed in only 1 patient (2.2%). No patients had died at the last follow-up.

CONCLUSIONS

GKS for s-BSCM is a safe and effective alternative to surgical resection for reducing the rate of recurrent hemorrhage. Because the annual hemorrhage rate increases >5 years after GKS, clinicians should monitor patients closely to determine their subsequent treatment.