Tag: cavernous malformation

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Parietal trans‑sulcal para‑fascicular approach to lateral thalamic/internal capsule cavernous malformation

Acta Neurochirurgica (2021) 163:2497–2501

The surgical management of deep brain lesions is challenging, with significant morbidity. Advances in surgical technology have presented the opportunity to tackle these lesions.

Methods We performed a complete resection of a thalamic/internal capsule CM using a tubular retractor system via a parietal trans-sulcal para-fascicular (PTPF) approach without collateral injury to the nearby white matter tracts.

Conclusion PTPF approach to lateral thalamic/internal capsule lesions can be safely performed without injury to eloquent white matter fibres. The paucity of major vessels along this trajectory and the preservation of lateral ventricle integrity make this approach a feasible alternative to traditional approaches.

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Optimal access route for pontine cavernous malformation resection with preservation of abducens and facial nerve function

J Neurosurg 135:683–692, 2021

The aim of this study was to analyze the differences between posterolateral and posteromedial approaches to pontine cavernous malformations (PCMs) in order to verify the hypothesis that a posterolateral approach is more favorable with regard to preservation of abducens and facial nerve function.

METHODS The authors conducted a retrospective analysis of 135 consecutive patients who underwent microsurgical resection of a PCM. The vascular lesions were first classified in a blinded fashion into 4 categories according to the possible or only reasonable surgical access route. In a second step, the lesions were assessed according to which approach was performed and different patient groups and subgroups were determined. In a third step, the modified Rankin Scale score and the rates of permanent postoperative abducens and facial nerve palsies were assessed.

RESULTS The largest group in this series comprised 77 patients. Their pontine lesion was eligible for resection from either a posterolateral or posteromedial approach, in contrast to the remaining 3 patient groups in which the lesion location already had dictated a specific surgical approach. Fifty-four of these 77 individuals underwent surgery via a posterolateral approach and 23 via a posteromedial approach. When comparing these 2 patient subgroups, there was a statistically significant difference between postoperative rates of permanent abducens (3.7% vs 21.7%) and facial (1.9% vs 21.7%) nerve palsies. In the entire patient population, the abducens and facial nerve deficit rates were 5.9% and 5.2%, respectively, and the modified Rankin Scale score significantly decreased from 1.6 ± 1.1 preoperatively to 1.0 ± 1.1 at follow-up.

CONCLUSIONS The authors’ results suggest favoring a posterolateral over a posteromedial access route to PCMs in patients in whom a lesion is encountered that can be removed via either surgical approach. In the present series, the authors have found such a constellation in 57% of all patients. This retrospective analysis confirms their hypothesis in a large patient cohort. Additionally, the authors demonstrated that 4 types of PCMs can be distinguished by preoperatively evaluating whether only one reasonable or two alternative surgical approaches are available to access a specific lesion. The rates of postoperative sixth and seventh nerve palsies in this series are substantially lower than those in the majority of other published reports.

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Intraoperative facial motor evoked potential monitoring for pontine cavernous malformation resection

J Neurosurg 132:265–271, 2020

The aim of this study was to predict postoperative facial nerve function during pontine cavernous malformation surgery by monitoring facial motor evoked potentials (FMEPs).

METHODS From 2008 to 2017, 10 patients with pontine cavernous malformations underwent total resection via the trans–fourth ventricle floor approach with FMEP monitoring. House-Brackmann grades and Karnofsky Performance Scale (KPS) scores were obtained pre- and postoperatively. The surgeries were performed using one of 2 safe entry zones into the brainstem: the suprafacial triangle and infrafacial triangle approaches. Six patients underwent the suprafacial triangle approach, and 4 patients underwent the infrafacial triangle approach. A cranial peg screw electrode was used to deliver electrical stimulation for FMEP by a train of 4 or 5 pulse anodal constant current stimulation. FMEP was recorded from needle electrodes on the ipsilateral facial muscles and monitored throughout surgery by using a threshold- level stimulation method.

RESULTS FMEPs were recorded and analyzed in 8 patients; they were not recorded in 2 patients who had severe preoperative facial palsy and underwent an infrafacial triangle approach. Warning signs appeared in all patients who underwent the suprafacial triangle approach. However, after temporarily stopping the procedures, FMEP findings during surgery showed recovery of the thresholds. FMEPs in patients who underwent the infrafacial triangle approach were stable during the surgery. House-Brackmann grades were unchanged postoperatively in all patients. Postoperative KPS scores improved in 3 patients, decreased in 1, and remained the same in 6 patients.

CONCLUSIONS FMEPs can be used to monitor facial nerve function during surgery for pontine cavernous malformations, especially when the suprafacial triangle approach is performed.

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Prospective validation of a molecular prognostication panel for clival chordoma

J Neurosurg 130:1528–1537, 2019

There are currently no reliable means to predict the wide variability in behavior of clival chordoma so as to guide clinical decision-making and patient education. Furthermore, there is no method of predicting a tumor’s response to radiation therapy.

METHODS A molecular prognostication panel, consisting of fluorescence in situ hybridization (FISH) of the chromosomal loci 1p36 and 9p21, as well as immunohistochemistry for Ki-67, was prospectively evaluated in 105 clival chordoma samples from November 2007 to April 2016. The results were correlated with overall progression-free survival after surgery (PFSS), as well as progression-free survival after radiotherapy (PFSR).

RESULTS Although Ki-67 and the percentages of tumor cells with 1q25 hyperploidy, 1p36 deletions, and homozygous 9p21 deletions were all found to be predictive of PFSS and PFSR in univariate analyses, only 1p36 deletions and homozygous 9p21 deletions were shown to be independently predictive in a multivariate analysis. Using a prognostication calculator formulated by a separate multivariate Cox model, two 1p36 deletion strata (0%–15% and > 15% deleted tumor cells) and three 9p21 homozygous deletion strata (0%–3%, 4%–24%, and ≥ 25% deleted tumor cells) accounted for a range of cumulative hazard ratios of 1 to 56.1 for PFSS and 1 to 75.6 for PFSR.

CONCLUSIONS Homozygous 9p21 deletions and 1p36 deletions are independent prognostic factors in clival chordoma and can account for a wide spectrum of overall PFSS and PFSR. This panel can be used to guide management after resection of clival chordomas.

 

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The future of open vascular neurosurgery: perspectives on cavernous malformations, AVMs, and bypasses for complex aneurysms

Despite the erosion of microsurgical case volume because of advances in endovascular and radiosurgical therapies, indications remain for open resection of pathology and highly technical vascular repairs. Treatment risk, efficacy, and durability make open microsurgery a preferred option for cerebral cavernous malformations, arteriovenous malformations (AVMs), and many aneurysms.

In this paper, a 21-year experience with 7348 cases was reviewed to identify trends in microsurgical management. Brainstem cavernous malformations (227 cases), once considered inoperable and managed conservatively, are now resected in increasing numbers through elegant skull base approaches and newly defined safe entry zones, demonstrating that microsurgical techniques can be applied in ways that generate entirely new areas of practice.

Despite excellent results with microsurgery for low-grade AVMs, brain AVM management (836 cases) is being challenged by endovascular embolization and radiosurgery, as well as by randomized trials that show superior results with medical management. Reviews of ARUBA-eligible AVM patients treated at high-volume centers have demonstrated that open microsurgery with AVM resection is still better than many new techniques and less invasive approaches that are occlusive or obliterative. Although the volume of open aneurysm surgery is declining (4479 cases), complex aneurysms still require open microsurgery, often with bypass techniques. Intracranial arterial reconstructions with reimplantations, reanastomoses, in situ bypasses, and intracranial interpositional bypasses (third-generation bypasses) augment conventional extracranial-intracranial techniques (first- and second-generation bypasses) and generate innovative bypasses in deep locations, such as for anterior inferior cerebellar artery aneurysms. When conventional combinations of anastomoses and suturing techniques are reshuffled, a fourth generation of bypasses results, with eight new types of bypasses. Type 4A bypasses use in situ suturing techniques within the conventional anastomosis, whereas type 4B bypasses maintain the basic construct of reimplantations or reanastomoses but use an unconventional anastomosis. Bypass surgery (605 cases) demonstrates that open microsurgery will continue to evolve. The best neurosurgeons will be needed to tackle the complex lesions that cannot be managed with other modalities. Becoming an open vascular neurosurgeon will be intensely competitive. The microvascular practice of the future will require subspecialization, collaborative team effort, an academic medical center, regional prominence, and a large catchment population, as well as a health system that funnels patients from hospital networks outside the region. Dexterity and meticulous application of microsurgical technique will remain the fundamental skills of the open vascular neurosurgeon.

 

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Contralateral anterior interhemispheric transcallosal- transrostral approach to the subcallosal region

J Neurosurg 129:508–514, 2018

The authors report a novel surgical route from a superior anatomical aspect—the contralateral anterior interhemispheric-transcallosal-transrostral approach—to a lesion located in the subcallosal region. The neurosurgical approach to the subcallosal region is challenging due to its deep location and close relationship with important vascular structures. Anterior and inferior routes to the subcallosal region have been described but risk damaging the branches of the anterior cerebral artery.

METHODS Three formalin-fixed and silicone-injected adult cadaveric heads were studied to demonstrate the relationships between the transventricular surgical approach and the subcallosal region. The surgical, clinical, and radiological history of a 39-year-old man with a subcallosal cavernous malformation was retrospectively used to document the neurological examination and radiographic parameters of such a case.

RESULTS The contralateral anterior interhemispheric-transcallosal-transrostral approach provides access to the subcallosal area that also includes the inferior portion of the pericallosal cistern, lamina terminalis cistern, the paraterminal and paraolfactory gyri, and the anterior surface of the optic chiasm. The approach avoids the neurocritical perforating branches of the anterior communicating artery.

CONCLUSIONS The contralateral anterior interhemispheric-transcallosal-transrostral approach may be an alternative route to subcallosal area lesions, with less risk to the branches of the anterior cerebral artery, particularly the anterior communicating artery perforators.

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Transcondylar approach for resection of lateral medullary cavernous malformation

Acta Neurochir (2018) 160:291–294

Resection of a medullary cavernous malformation requires aggressive exposure, but there is controversy on how much occipital condyle can be safely removed during the transcondylar approach.

Method We describe and demonstrate the use of the transcondylar approach to a medullary cavernous malformation, with emphasis on adequate surgical exposure while preserving the atlanto-occipital joint.

Conclusions Despite conservative handling of the occipital condyle, craniocervical stability may vary in patients after transcondylar surgery. A “dynamic” computer tomography, with views of the atlanto-occipital joint at each end-rotational extreme, may be the best postoperative assessment tool to evaluate the stability of the craniocervical junction.

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Impact of Timing of Intervention Among 397 Consecutively Treated Brainstem Cavernous Malformations

Neurosurgery 81:620–626, 2017

Surgical resection of brainstem cavernous malformations (BSCMs) is challenging, and patient selection and timing of intervention remain controversial.

OBJECTIVE: To evaluate the impact of surgical timing and predictors of neurological outcome after surgical resection of BSCMs.

METHODS: Consecutive adult patients (≥18 years) with BSCMs undergoing surgical resection between 1985 and 2014 by the senior author (RFS)were retrospectively reviewed. Patient demographics, lesion characteristics, imaging results, surgical approach, and perioperative and long-term neurological morbidity were analyzed.

RESULTS: Data were analyzed for a total of 397 adult patients (160, 40% male).On univariate analysis, a greater proportion of patients treated within 6 weeks of hemorrhage had an improved Glasgow Outcome Scale score (P = .06). On logistic regression analysis, patients treated within 6weeks of hemorrhage experienced improved clinical outcomes (odds ratio = 1.73; 95% confidence interval = 1.06-2.83; P = .03).

CONCLUSIONS: Although BSCM surgery is associated with significant perioperative morbidity and mortality, favorable long-term hemorrhage rates and symptom resolution can be achieved in a carefully selected group of patients. Overall, patients treated acutely, within 6 weeks, benefited the most from surgical intervention.

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

J Neurosurg 127:480–491, 2017

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%) (c2 = 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 presentation 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.

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Endoscopic endonasal transclival resection of a ventral pontine cavernous malformation

J Neurosurg 127:553–558, 2017

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.

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Hemorrhage from cerebral cavernous malformations

J Neurosurg 126:1079–1087, 2017

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.

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Qualitative analysis of spinal intramedullary lesions using PET/CT

Qualitative analysis of spinal intramedullary lesions using PET-CT.1

J Neurosurg Spine 23:613–619, 2015

Although the usefulness of PET for brain lesions has been established, few reports have examined the use of PET for spinal intramedullary lesions. This study investigated the diagnostic utility of PET/CT for spinal intramedullary lesions.

Methods l-[methyl-11C]-methionine (MET)– or [18F]-fluorodeoxyglucose (FDG)–PET/CT was performed in 26 patients with spinal intramedullary lesions. The region of interest (ROI) within the spinal cord parenchyma was placed manually in the axial plane. Maximum pixel counts in the ROIs were normalized to the maximum standardized uptake value (SUVmax) using subject body weight. For FDG-PET the SUVmax was corrected for lean body mass (SULmax) to exclude any influence of the patient’s body shape. Each SUV was analyzed based on histopathological results after surgery. The diagnostic validity of the SUV was further compared with the tumor proliferation index using the MIB-1 monoclonal antibody (MIB-1 index).

Results A total of 16 patients underwent both FDG-PET and MET-PET, and the remaining 10 patients underwent either FDG-PET or MET-PET. Pathological diagnoses included high-grade malignancy such as glioblastoma multiforme, anaplastic astrocytoma, or anaplastic ependymoma in 5 patients; low-grade malignancy such as hemangioblastoma, diffuse astrocytoma, or ependymoma in 12 patients; and nonneoplastic lesion including cavernous malformation in 9 patients. Both FDG and MET accumulated significantly in high-grade malignancy, and the SULmax and SUVmax correlated with the tumor proliferation index. Therapeutic response after chemotherapy or radiation in high-grade malignancy was well monitored. However, a significant difference in SULmax and SUVmax for FDG-PET and MET-PET was not evident between low-grade malignancy and nonneoplastic lesions.

Conclusions Spinal PET/CT using FDG or MET for spinal intramedullary lesions appears useful and practical, particularly for tumors with high-grade malignancy. Differentiation of tumors with low-grade malignancy from nonneoplastic lesions may still prove difficult. Further technological refinement, including the selection of radiotracer or analysis evaluation methods, is needed.

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Pathological response of cavernous malformations following radiosurgery

Pathological response of cavernous malformations following radiosurgery

J Neurosurg 123:938–944, 2015

Stereotactic radiosurgery (SRS) is a therapeutic option for repeatedly hemorrhagic cavernous malformations (CMs) located in areas deemed to be high risk for resection. During the latency period of 2 or more years after SRS, recurrent hemorrhage remains a persistent risk until the obliterative process has finished. The pathological response to SRS has been studied in relatively few patients. The authors of the present study aimed to gain insight into the effect of SRS on CM and to propose possible mechanisms leading to recurrent hemorrhages following SRS.

Methods During a 13-year interval between 2001 and 2013, bleeding recurred in 9 patients with CMs that had been treated using Gamma Knife surgery at the authors’ institution. Microsurgical removal was subsequently performed in 5 of these patients, who had recurrent hemorrhages between 4 months and 7 years after SRS. Specimens from 4 patients were available for analysis and used for this report.

Results Histopathological analysis demonstrated that vascular sclerosis develops as early as 4 months after SRS. In the samples from 2 to 7 years after SRS, sclerotic vessels were prominent, but there were also vessels with incomplete sclerosis as well as some foci of neovascularization.

Conclusions: Recurrent bleeding after SRS for CM could be related to incomplete sclerosis of the vessels, but neovascularization may also play a role.

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The 6 thalamic regions: surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes

The 6 thalamic regions- surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes

J Neurosurg 123:676–685, 2015

The ideal surgical approach to thalamic cavernous malformations (CMs) varies according to their location within the thalamus. To standardize surgical approaches, the authors have divided the thalamus into 6 different regions and matched them with the corresponding surgical approach.

Methods The regions were defined as Region 1 (anteroinferior), Region 2 (medial), Region 3 (lateral), Region 4 (posterosuperior), Region 5 (lateral posteroinferior), and Region 6 (medial posteroinferior). The senior author’s surgical experience with 46 thalamic CMs was reviewed according to this classification. An orbitozygomatic approach was used for Region 1; anterior ipsilateral transcallosal for Region 2; anterior contralateral transcallosal for Region 3; posterior transcallosal for Region 4; parietooccipital transventricular for Region 5; and supracerebellar-infratentorial for Region 6.

Results Region 3 was the most common location (17 [37%]). There were 5 CMs in Region 1 (11%), 9 in Region 2 (20%), 17 in Region 3 (37%), 3 in Region 4 (6%), 4 in Region 5 (9%), and 8 in Region 6 (17%). Complete resection was achieved in all patients except for 2, who required a second-stage operation. The mean follow-up period was 1.7 years (range 6 months–9 years). At the last clinical follow-up, 40 patients (87%) had an excellent or good outcome (modified Rankin Scale [mRS] scores 0–2) and 6 (13%) had poor outcome (mRS scores 3–4). Relative to their preoperative condition, 42 patients (91%) were unchanged or improved, and 4 (9%) were worse.

Conclusions The authors have presented the largest series reported to date of surgically treated thalamic CMs, achieving excellent results using this methodology. In the authors’ experience, conceptually dividing the thalamus into 6 different regions aids in the selection of the ideal surgical approach for a specific region.

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The 6 thalamic regions: surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes

Cavernous_Malformation_of_Thalamus

J Neurosurg (123)3: 676-685

The ideal surgical approach to thalamic cavernous malformations (CMs) varies according to their location within the thalamus. To standardize surgical approaches, the authors have divided the thalamus into 6 different regions and matched them with the corresponding surgical approach.

METHODS
The regions were defined as Region 1 (anteroinferior), Region 2 (medial), Region 3 (lateral), Region 4 (posterosuperior), Region 5 (lateral posteroinferior), and Region 6 (medial posteroinferior). The senior author’s surgical experience with 46 thalamic CMs was reviewed according to this classification. An orbitozygomatic approach was used for Region 1; anterior ipsilateral transcallosal for Region 2; anterior contralateral transcallosal for Region 3; posterior transcallosal for Region 4; parietooccipital transventricularfor Region 5; and supracerebellar-infratentorial for Region 6.

RESULTS
Region 3 was the most common location (17 [37%]). There were 5 CMs in Region 1 (11%), 9 in Region 2 (20%), 17 in Region 3 (37%), 3 in Region 4 (6%), 4 in Region 5 (9%), and 8 in Region 6 (17%). Complete resection was achieved in all patients except for 2, who required a second-stage operation. The mean follow-up period was 1.7 years (range 6 months-9 years). At the last clinical follow-up, 40 patients (87%) had an excellent or good outcome (modified Rankin Scale [mRS] scores 0–2) and 6 (13%) had poor outcome (mRS scores 3–4). Relative to their preoperative condition, 42 patients (91%) were unchanged or improved, and 4 (9%) were worse.

CONCLUSIONS
The authors have presented the largest series reported to date of surgically treated thalamic CMs, achieving excellent results using this methodology. In the authors’ experience, conceptually dividing the thalamus into 6 different regions aids in the selection of the ideal surgical approach for a specific region.

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Radiosurgery for symptomatic cavernous malformations: A multi‑institutional retrospective study in Japan

Gamma knife radiosurgery for brainstem cavernous malformations- should a patient wait for the rebleed?

Surg Neurol Int 2015;6:S249-57

A group study for symptomatic cavernous malformation (CM) treated with gamma knife (GK) surgery was performed.

Methods: A total of 298 cases collected from 23 GK centers across Japan were included. Hemorrhage was the most common manifestation, followed by seizures and neurological deficits. Most of the lesions were located in the brainstem and basal ganglia, followed by the cerebral or cerebellar hemispheres. The CMs, which had a mean diameter of 14.8 mm, were treated using GK surgery with a mean marginal dose of 14.6 Gy.

Results: In terms of hemorrhage‑free survival (HFS), a marked dissociation was confirmed between the hemorrhage and seizure groups, while no obvious difference was noted between sexes. Superficial CMs located in cerebellum or lobar regions responded to the treatment better than deeply located CMs in the basal ganglia or brainstem. No significant difference of dose‑dependent response was seen for three different ranges of marginal dose: Less than 15 Gy, between 15 and 20 Gy, and more than 20 Gy. Complications were more frequent after a marginal dose of over 15 Gy and in patients with lesions more than 15 mm in diameter. The rates of annual hemorrhage were estimated to be 7.4% during the first 2 years after radiosurgery and 2.8% thereafter. The overall hemorrhage rate after radiosurgery was 4.4%/year/patient.

Conclusion: The risk of hemorrhage is considerably reduced after GK treatment. The HFS as well as annual hemorrhage rate after GK treatment was apparently superior to that after conservative treatment for symptomatic CMs. To optimize the success of GK treatment, it is important to reduce the incidence of complications.

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Gamma knife radiosurgery for brainstem cavernous malformations: should a patient wait for the rebleed?

Gamma knife radiosurgery for brainstem cavernous malformations- should a patient wait for the rebleed?

Acta Neurochir (2014) 156:1937–1946

The effectiveness of stereotactic radiosurgery (SRS) for cavernous malformation (CM) has not been fully assessed. Consequently, observation is usually recommended when a bleeding CM is initially discovered. Recurrent bleeding occurs with CMs, and these repeat hemorrhages can result in additional morbidity.

Methods From 1992 to 2011, 49 patients with brainstem CMs were treated with Gamma Knife radiosurgery (GKS). We classified patients into two groups: Group A (n=31), patients who underwent GKS for a CM following a single symptomatic bleed, and group B (n=18), patients who underwent GKS for a CM following two or more symptomatic bleeds. The mean marginal dose of radiation was 13.1 Gy (range 9.0- 16.8 Gy): 12.8 Gy in group A and 13.7 Gy in group B. The mean follow-up period was 64.0 months (range 1-171 months).

Results In group A, the annual hemorrhage rate (AHR) following GKS was 7.06 % within the first 2 years and 2.03 % after 2 years. In group B, four patients (22.2 %) developed new or worsening neurologic deterioration as a result of repeat hemorrhages. In group B, the AHR was 38.36 % prior to GKS, 9.84 % within the first two years, and 1.50 % after two years. There was no statistically significant difference in the AHRs at each follow-up period after GKS between the two groups. Adverse radiation effects (AREs) developed in a total of four patients (8.2%); among them, one patient (2.0 %) developed a permanent case of diplopia. No mortality occurred in this series.

Conclusion In this study, GKS was demonstrated to be a safe and effective alternative treatment for brain stem CMs that resulted in a reduction in the AHR. Consequently, we suggest that even CM patients who have suffered only a single bleed should not be contraindicated for SRS.

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Lateral inferior cerebellar peduncle approach to dorsolateral medullary cavernous malformation

Dorsolateral medullary cavernous malformations

J Neurosurg 121:723–729, 2014

Brainstem cavernous malformations (BSCMs) present a unique therapeutic challenge to neurosurgeons. Resection of BSCMs is typically reserved for lesions that reach pial or ependymal surfaces. The current study investigates the lateral inferior cerebellar peduncle as a corridor to dorsolateral medullary BSCMs.

Methods. In this retrospective review, the authors present the cases of 4 patients (3 women and 1 man) who had a symptomatic dorsolateral cavernous malformation with radiographic and clinical evidence of hemorrhage.

Results. All patients underwent excision of the cavernous malformation via a far-lateral suboccipital craniotomy through the foramen of Luschka and with an incision in the inferior cerebellar peduncle. On intraoperative examination, 2 of the 4 patients had hemosiderin staining on the surface of the peduncle. All lesions were completely excised and all patients had a good or excellent outcome (modified Rankin Scale scores of 0 or 1).

Conclusions. This case series illustrates that intrinsic lesions of the dorsolateral medulla can be safely removed laterally through the foramen of Luschka and the inferior cerebellar peduncle.

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Hemorrhage risks and functional outcomes of untreated brainstem cavernous malformations

brainstem cavernous malformations

J Neurosurg 121:32–41, 2014

Cerebral cavernous malformations have been studied widely, but the natural history of brainstem cavernous malformations (CMs) is not well defined, and hemorrhages caused by brainstem CMs are devastating. The goal of this study was to quantify the hemorrhage risks and functional outcomes of patients with brainstem CMs.

Methods. This prospective, longitudinal, cohort study included patients with brainstem CMs diagnosed between 1985 and 2012. The clinical courses of all patients were recorded. Predictors of hemorrhage and the overall untreated outcomes were evaluated.

Results. A total of 331 patients (46.5% female) were included, with a mean follow-up duration of 6.5 years. The annual hemorrhage rates in patients initially presenting with hemorrhage with (n = 215) or without (n = 34) focal neurological deficits were 15.9% and 12.4%, respectively. However, the annual hemorrhage rate was 8.7% in patients initially presenting without hemorrhage (n = 82). The risk factors for hemorrhage were female sex (hazard ratio [HR] 1.445, p = 0.041), prior hemorrhage (HR 1.277, p = 0.029), and perilesional edema (HR 1.830, p = 0.002). Overall, neurological function at the most recent assessment was improved compared with neurological function at diagnosis. Additionally, 307 patients (92.7%) improved or stabilized, 268 (81.0%) lived independently, and 95 (28.7%) completely recovered. Predictors favoring complete recovery were no prospective hemorrhage (HR 1.958, p = 0.001), younger age (HR 1.268, p = 0.001), and small lesion size (HR 1.578, p = 0.004).

Conclusions. Patients’ initial presentation predicts their prospective annual hemorrhage rate. This study suggests that several strong risk factors for hemorrhage and predictors of brainstem CM outcomes may enable clinicians to evaluate the potential hemorrhage risks of their patients and design personalized treatments.

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Long-term natural history of incidentally discovered cavernous malformations in a single-center cohort

cavmal2_600

J Neurosurg 120:1188–1192, 2014

The aim of this study was to determine the prospective hemorrhage rate in a group of retrospectively identified patients in whom symptoms had an unclear relationship to an intracerebral cavernous malformation (ICM) or the malformation itself was an incidental finding.

Methods. Patients with incidentally discovered ICMs diagnosed between 1989 and 1999 were identified from a previously published cohort. Those with ICMs having an unclear relationship with existing symptoms were also eligible for analysis. Updated clinical and radiographic data pertaining to symptomatic intracerebral hemorrhage related to the ICM or new seizures were obtained through medical chart review and mail survey. In select patients, phone calls were made and death certificates were obtained when possible. The prospective hemorrhage rate was calculated as the number of prospective hemorrhages divided by the number of patient-years of follow-up.

Results. There were 1311 patient-years of follow-up among the 107 patients (49.5% male; mean age at diagnosis 52 years) eligible for this study. Forty-four patients died in the follow-up period, and the cause of death could be determined in 34 (77%). Two patients had a prospective hemorrhage, which was definitively related to the ICM in only one. Thus, the definitive prospective bleed rate was 0.08% per patient-year. No new seizures developed in any of the patients during the follow-up period.

Conclusions. The risk of prospective hemorrhage in patients presenting asymptomatically with ICM is very low. This information can be useful in managing such patients and may be most applicable to those with a single ICM.

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