Cavernous malformation of brainstem, thalamus, and basal ganglia: a series of 176 patients

Left Internal Capsule Cavernoma Using the Superior Frontal Sulcus as a Surgical Corridor: Why and How to Do It: 2-Dimensional Operative Video

Cavernous angioma is a sinusoidal dilatation covered by a single layer of endothelium, separated by a collagen matrix with elastin and smooth muscle.1 The prevalence in the general population is estimated at 0.4% to 0.9%,2 representing around 5% to 10% of all vascular malformations.3 Studies indicate 9% to 35% of cavernomas are found in deep locations such as the brainstem, thalamus, and basal ganglia.4-6 Common symptoms of these deep lesions are cranial nerve deficit, hemiparesis, and paresthesia. These lesions have high rates of rebleeding after the first episode of bleeding but present excellent results of surgical resection and modified Rankin in the long term.7-13 Internal capsule cavernomas are particularly challenging due to the important projection fibers surround them. Although the gold standard of treatment is microsurgery, there needs to be a consensus on the best approach for lesions of this topography. We present a video case of a female in her 50s with right hemiparesis and dysphasia, exhibiting grade 3/5 strength on the right side. T1 MRI revealed a high intensity, heterogeneous, multinodular signal in the left basal ganglia, with tractography showing the lesion dividing the posterior limb of the internal capsule amid fibers of the right corticospinal tract. The patient consented to the procedure and to the publication of his/her image. This study was approved by the Ethics and Research Committee of our institution. We demonstrated that the superior frontal sulcus is a safe corridor to surgically cure cavernomas of the internal capsule, with the recovery of previous deficits.

Outcomes after surgical and nonsurgical treatment of pediatric cerebral cavernous malformation

Importance

Pediatric cerebral cavernous malformation (CCM) is a rarely encountered vascular entity. Comparative study on surgical excision and nonsurgical management outcomes of CCM in pediatrics is limited.

Objective

To determine the demographic characteristics, hemorrhage rate, and long-term outcomes of pediatric patients with CCM.

Methods

A retrospective study of pediatric patients with CCM in Chinese PLA General Hospital was conducted between January 2004 and January 2019. We compared the clinical characteristics, radiological features, and outcomes of the surgical and nonsurgical groups.

Results

Seventy-nine children were included, with 69.6% being boys, and the average age was 11.8 ± 5.5 years. The annual retrospective hemorrhagic rate was 5.7% per patient per year. Fifty-six children (70.9%) underwent surgical excision, and they were more likely to present with seizure symptoms (P = 0.011), have a higher proportion of larger lesion size (P = 0.008), less likely to have durations ≤10 days (P = 0.048), and less likely to have supratentorial deep CCM (P = 0.014) compared to children who received nonsurgical management. Total resection was achieved in most surgical cases (55, 98.2%). During the 143.9 ± 50.8 months of follow-up, 44 patients (78.6%) achieved improvement, 12 patients (17.8%) remained the same, and two (3.6%) experienced worsening. In the nonsurgical management group, 14 children (60.9%) experienced symptom improvement, eight (34.8%) remained the same, and one (4.3%) worsened, with a re-hemorrhagic risk of 8.7%.

Interpretation

Surgical removal of pediatric CCM can eliminate the risk of hemorrhage and lead to satisfactory outcomes. For children undergoing nonsurgical management, long-term close monitoring is essential due to the life-long risk of hemorrhage.

Superior frontal sulcus: a non-eloquent corridor for cavernomas of the internal capsule

Introduction

Deep cavernomas of eloquent areas, located in the region of the basal nuclei and thalamus, account for 9 to 36% of these encephalic vascular malformations. Internal capsule cavernomas are particularly challenging, as they are surrounded by important projection fibers and their manipulation can lead to permanent deficits. To demonstrate through surgical cases that cavernomas of the internal capsule can be approached by frontal craniotomy, via the superior frontal sulcus, in a curative manner and with low morbidity.

Methods

We presented two cases of cavernomas of the internal capsule operated, whose treatment was microsurgical resection via frontal craniotomy and access to the lesion via the superior frontal sulcus, described step-by-step. To elucidate the rationale behind the decision, we used preoperative images with an emphasis on the patients' tractography and the importance of comparing these images with anatomical specimens dissected in the neuroanatomy and microsurgery laboratory.

Results

The two cases of internal capsule cavernomas, one in the anterior limb and the other in the posterior limb, were treated surgically via the superior frontal sulcus.

Discussion

Both patients showed radiological cure and clinical improvement in the post-operative segment. The patient consented to the procedure and to the publication of his/her image. Treatment of internal capsule cavernomas via the superior frontal sulcus has proven to be a safe and effective option.

Cavernous malformations of the central nervous system: An international consensus statement

Introduction

Cavernous malformations (CM) of the central nervous system constitute rare vascular lesions. They are usually asymptomatic, which has allowed their management to become quite debatable. Even when they become symptomatic their optimal mode and timing of treatment remains controversial.

Research question

A consensus may navigate neurosurgeons through the decision-making process of selecting the optimal treatment for asymptomatic and symptomatic CMs.

Material and methods

A 17-item questionnaire was developed to address controversial issues in relation to aspects of the treatment, surgical planning, optimal surgical strategy for specific age groups, the role of stereotactic radiosurgery, as well as a follow-up pattern. Consequently, a three-stage Delphi process was ran through 19 invited experts with the goal of reaching a consensus. The agreement rate for reaching a consensus was set at 70%.

Results

A consensus for surgical intervention was reached on the importance of the patient's age, symptomatology, and hemorrhagic recurrence; and the CM's location and size. The employment of advanced MRI techniques is considered of value for surgical planning. Observation for asymptomatic eloquent or deep-seated CMs represents the commonest practice among our panel. Surgical resection is considered when a deep-seated CM becomes symptomatic or after a second bleeding episode. Asymptomatic, image-proven hemorrhages constituted no indication for surgical resection for our panelists. Consensus was also reached on not resecting any developmental venous anomalies, and on resecting the associated hemosiderin rim only in epilepsy cases.

Discussion and conclusion

Our Delphi consensus provides an expert common practice for specific controversial issues of CM patient management.

Increased intrinsic membrane excitability is associated with hypertrophic olivary degeneration in spinocerebellar ataxia type 1

One of the characteristic areas of brainstem degeneration across multiple spinocerebellar ataxias (SCAs) is the inferior olive (IO), a medullary nucleus that plays a key role in motor learning. In addition to its vulnerability in SCAs, the IO is also susceptible to a distinct pathology known as hypertrophic olivary degeneration (HOD). Clinically, HOD has been exclusively observed after lesions in the brainstem disrupt inhibitory afferents to the IO. Here, for the first time, we describe HOD in another context: spinocerebellar ataxia type 1 (SCA1). Using the genetically-precise SCA1 knock-in mouse model (SCA1-KI; both sexes used), we assessed SCA1-associated changes in IO neuron structure and function. Concurrent with degeneration, we found that SCA1-KI IO neurons are hypertrophic, exhibiting early dendrite lengthening and later somatic expansion. Unlike in previous descriptions of HOD, we observed no clear loss of IO inhibitory innervation; nevertheless, patch-clamp recordings from brainstem slices reveal that SCA1-KI IO neurons are hyperexcitable. Rather than synaptic disinhibition, we identify increases in intrinsic membrane excitability as the more likely mechanism underlying this novel SCA1 phenotype. Specifically, transcriptome analysis indicates that SCA1-KI IO hyperexcitability is associated with a reduced medullary expression of ion channels responsible for spike afterhyperpolarization (AHP) in IO neurons - a result that has a functional consequence, as SCA1-KI IO neuron spikes exhibit a diminished AHP. These results reveal membrane excitability as a potential link between disparate causes of IO degeneration, suggesting that HOD can result from any cause, intrinsic or extrinsic, that increases excitability of the IO neuron membrane.

Laser Interstitial Thermal Therapy for Cerebral Cavernous Malformations: A Systematic Review of Indications, Safety, and Outcomes

BACKGROUND

Cerebral cavernous malformations (CCM) in deep eloquent areas present a surgical challenge. Laser interstitial thermal therapy (LITT) may present itself as a safe minimally invasive treatment option.

OBJECTIVE

To systematically review the indications, safety, and outcomes of LITT for CCM.

METHODS

Electronic databases were searched from inception to October 7, 2021 for articles with CCM and LITT keywords. Studies describing CCMs treated with LITT were included.

RESULTS

A total of 32 patients with CCMs in lobar (79%), basal ganglia (12%), and brainstem (9%) locations were treated with LITT. Indications for LITT included drug-resistant seizures (75%), unacceptable surgical risk (22%), recurrent hemorrhage (16%), and early intervention to discontinue antiepileptic drugs (3%). No death or CCM-associated intracranial hemorrhage occurred intraoperatively or postoperatively, and most patients experienced no adverse effects or transient effects that resolved at follow-up (84%). Of those treated for CCM-associated epilepsy, 83% experienced Engel class I seizure freedom and most were class IA (61%). Most patients experienced symptomatic improvement (93%), and a decrease in antiepileptic drugs was reported in more than half of patients (56%), with 28% able to discontinue all antiepilepsy medications after LITT.

CONCLUSIONS

LITT seems to be a safe treatment for CCMs located in deep eloquent areas and in lesions presenting with medically refractory seizures or recurrent hemorrhages. Randomized studies are needed to further elucidate its efficacy in treating CCM.

Long-term outcomes after surgery for brainstem cavernous malformations: analysis of 46 consecutive cases

OBJECTIVE

The objective of this study was to evaluate the long-term outcomes after resection of brainstem cavernous malformations (BSCMs) and to assess the usefulness of the Lawton grading system in these cases.

METHODS

This retrospective study analyzed 46 consecutive patients with BSCMs operated on between July 1990 and December 2020. Outcomes at the last follow-up were defined as favorable (modified Rankin Scale [mRS] score 0-2) or unfavorable (mRS score > 2).

RESULTS

The study cohort comprised 24 men (52%) and 22 women (48%), ranging in age from 8 to 78 years old (median 37 years). In 19 patients (41%), the preoperative mRS score was > 2. All patients had hemorrhagic BSCM. There were 12 (26%) mesencephalic, 19 (41%) pontine, 7 (15%) medullary, and 8 (17%) cerebellar peduncle lesions, with a maximal diameter ranging from 5 to 40 mm (median 15 mm). In total, 24 BSCMs (52%) had bilateral extension crossing the brainstem midline. Lawton grades of 0, I, II, III, IV, V, and VI were defined in 3 (7%), 2 (4%), 10 (22%), 11 (24%), 8 (17%), 7 (15%), and 5 (11%) cases, respectively. Total resection of BSCMs was attained in 43 patients (93%). There were no perioperative deaths. Excluding the 3 most recent cases, the length of follow-up ranged from 56 to 365 months. The majority of patients demonstrated good functional recovery, but regress of the preexisting oculomotor nerve deficit was usually incomplete. No new hemorrhagic events were noted after total resection of BSCMs. In 42 patients (91%), the mRS score at the time of last follow-up was ≤ 2 (favorable outcome), and in 18 (39%), it was 0 (absence of neurological symptoms). Forty-four patients (96%) demonstrated clinical improvement and 2 (4%) had no changes compared with the preoperative period. Multivariate analysis revealed that only lower Lawton grade had a statistically significant independent association (p = 0.0280) with favorable long-term outcome. The area under the receiver operating characteristic curve for prediction of favorable outcome with 7 available Lawton grades of BSCM was 0.93.

CONCLUSIONS

Resection of hemorrhagic BSCMs by an experienced neurosurgeon may be performed safely and effectively, even in severely disabled patients. In the authors' experience, preexisting oculomotor nerve palsy represents the main cause of permanent postoperative neurological morbidity. The Lawton grading system effectively predicts long-term outcome after surgery.

Nomogram for predicting an individual prospective hemorrhage risk in untreated brainstem cavernous malformations

OBJECTIVE

In this study, the authors aimed to create a nomogram for precisely predicting the 5-year prospective hemorrhage risk in brainstem cavernous malformations (BSCMs).

METHODS

Patients with confirmed BSCMs in a single-center prospective observational series from January 2012 to December 2016 were included in the present study for nomogram building and validation. The concordance index (C-index), calibration curves, and decision curve analysis were used to evaluate the predictive accuracy, discriminative ability, and clinical usefulness of the nomogram. Then, a nomogram-based risk stratification model for untreated BSCMs was developed.

RESULTS

In total, 600 patients were included in the study; 417 patients who had been enrolled before July 2015 were divided into the training and validation cohorts, and 183 subsequently enrolled patients were used as the external validation cohort. By applying a backward stepwise procedure in the multivariable Cox model, variables, including prior hemorrhage (HR 1.69), hemorrhage on admission (HR 3.33), lesion size > 1.5 cm (HR 1.84), lesion depth (HR 2.35), crossing the axial midpoint (HR 1.94), and developmental venous anomaly (HR 2.62), were incorporated to develop a nomogram. The Harrell C-index values for a 5-year prospective hemorrhage were 0.752 (95% CI 0.687–0.816), 0.801 (95% CI 0.665–0.936), and 0.758 (95% CI 0.674–0.842) in the training, internal validation, and external validation cohorts, respectively. The nomogram performed well in terms of consistency between prediction and actual observation according to the calibration curve. The patients could be classified into three distinct (low, medium, and high) risk groups using the final score of this nomogram.

CONCLUSIONS

Independent predictors of the 5-year hemorrhage risk in untreated BSCMs were selected to create the first nomogram for predicting individual prospective hemorrhage. The nomogram was able to stratify patients into different risk groups and assist in clinical decision-making.

Direct brainstem somatosensory evoked potentials for cavernous malformations

OBJECTIVE

Brainstem cavernous malformations (CMs) often require resection due to their aggressive natural history causing hemorrhage and progressive neurological deficits. The authors report a novel intraoperative neuromonitoring technique of direct brainstem somatosensory evoked potentials (SSEPs) for functional mapping intended to help guide surgery and subsequently prevent and minimize postoperative sensory deficits.

METHODS

Between 2013 and 2019 at the Stanford University Hospital, intraoperative direct brainstem stimulation of primary somatosensory pathways was attempted in 11 patients with CMs. Stimulation identified nucleus fasciculus, nucleus cuneatus, medial lemniscus, or safe corridors for incisions. SSEPs were recorded from standard scalp subdermal electrodes. Stimulation intensities required to evoke potentials ranged from 0.3 to 3.0 mA or V.

RESULTS

There were a total of 1 midbrain, 6 pontine, and 4 medullary CMs-all with surrounding hemorrhage. In 7/11 cases, brainstem SSEPs were recorded and reproducible. In cases 1 and 11, peripheral median nerve and posterior tibial nerve stimulations did not produce reliable SSEPs but direct brainstem stimulation did. In 4/11 cases, stimulation around the areas of hemosiderin did not evoke reliable SSEPs. The direct brainstem SSEP technique allowed the surgeon to find safe corridors to incise the brainstem and resect the lesions.

CONCLUSIONS

Direct stimulation of brainstem sensory structures with successful recording of scalp SSEPs is feasible at low stimulation intensities. This innovative technique can help the neurosurgeon clarify distorted anatomy, identify safer incision sites from which to evacuate clots and CMs, and may help reduce postoperative neurological deficits. The technique needs further refinement, but could potentially be useful to map other brainstem lesions.

Endoscope-assisted resection of brainstem cavernous malformations

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.

Overview of cerebral cavernous malformations: comparison of treatment approaches

OBJECTIVES

The comparison of treatment efficacy for cerebral cavernous malformations (CCMs) has not yet been well researched.

DESIGN

PubMed, Cochrane Library, Science Direct, ISI Web of Science, Embase and additional sources were searched to identify cohort studies about the treatment of CCMs published between 1990 and 2020. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed; the Newcastle-Ottawa Scale was used to assess the risk of bias and to evaluate limitations based on selection/outcome biases. The cumulative incidences with 95% CIs were calculated using the random effects model. The models of Poisson distribution were applied to evaluate risk factors of poorer treatment outcome by calculating rate ratios within 100 person-years with 95% CIs.

RESULTS

A total of 100 cohorts yielding 8994 patients treated for CCMs within 41 098 person-years of follow-up were analysed. The efficacy of ensuring the prevention of haemorrhage was 97% in surgical, 86% in radiosurgical and 77% in the conservative treatment. The lowest mortality (1%) was after radiosurgery, and the highest persistent morbidity (22%) was in natural history series. Deep-seated and brainstem CCMs were associated with higher bleeding rates. Lobar localisation was a protective factor in all analyses. Patients with history of previous haemorrhage were exposed to higher risk of rebleeding. Male gender was a protective factor associated with lower risk of post-treatment haemorrhage.

CONCLUSIONS

Surgical resection of CCM is effective in ensuring the prevention of haemorrhage with acceptable morbidity and mortality, but conservative and radiosurgical management is a justified treatment alternative. Brainstem and deep-seated CCMs are predominantly associated with higher haemorrhage rates.

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.

Resection of Brainstem Cavernous Malformations: Pearls and Pitfalls for Minimizing Complications

BACKGROUND

Surgical management of brainstem cavernous malformations (CMs) is a controversial topic in the field of neurosurgery. These lesions have a propensity to hemorrhage, thereby disrupting surrounding brainstem eloquence.

METHODS

This article provides the personal reflections of the senior author and a narrative literature review on resection of brainstem CMs.

RESULTS

Here we discuss the indications for microsurgery, microsurgical techniques and nuances, and perioperative management considerations necessary to minimize complications during resection of brainstem CMs, which are lesions of venous origin.

CONCLUSIONS

The natural history of the lesion, risk of future hemorrhage, and potential for symptom resolution should be carefully considered when planning to resect brainstem CMs. Nuanced microsurgical techniques with minimal disruption of normal tissues provide the best chance of satisfactory outcomes.

Bilateral Hypertrophic Olivary Degeneration after Pontine Hemorrhage: A Case Report

BACKGROUND

Hemorrhage lesions may lead to bilateral hypertrophic olivary degeneration (HOD) through interruption of the dentato-rubral-olivary pathway. The pathological features of HOD are unusual neuronal trans-synaptic degenerative changes.

CASE SUMMARY

A 56-year-old female was admitted to our hospital because her lower extremities and left upper ones were unable to move for 3 mo, and the swelling of her right lower extremities became worse 3 days ago. She had a hypertension history. Her characteristic clinical manifestations are palatal myoclonus and nystagmus. The patient’s magnetic resonance imaging (MRI) results showed that she had bilateral HOD after an acute pontine hemorrhage. She was given symptomatic and supportive treatment. The gabapentin, the memantine and the trihexyphenidyl were taken twice a day each. The rehabilitation and psychotherapy were implemented. After 3 months of treatment, her eye symptoms improved.

CONCLUSION

Bilateral HOD is a rare phenomenon after pontine hemorrhage. The key to diagnosis lies in the clinical manifestations and MRI results.

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.

Cavernous malformations of the hypothalamus: a single-institution series of 12 cases and review of the literature

OBJECTIVE

There remains a paucity of literature on hypothalamic cavernous malformations (HCMs). Here, the authors present the largest series of HCMs to date and review the literature to gain additional insight into this rare disease subset.

METHODS

A prospectively managed database was retrospectively reviewed for patients diagnosed with symptomatic HCM and treated surgically between 1987 and 2019. Data gathered included demographics, presenting signs, radiological measurements, surgical approach, and postoperative events. Functional outcome was measured using the modified Rankin Scale (mRS) and Glasgow Outcome Scale-Extended (GOSE) pre- and postoperatively. A PRISMA guideline systematic review of HCM in the literature was performed.

RESULTS

Our cohort study consisted of 12 patients with symptomatic, and radiographically confirmed, HCM treated with microsurgery by the senior author (G.K.S.). An additional 16 surgically or conservatively managed patients were also identified from the literature, and the authors analyzed the data of all 28 patients (with 54% of patients being male; mean age 39 ± 16 years, range 10-68 years). Patients harboring HCMs most commonly presented with headache (16/28, 57%), short-term memory impairment (11/28, 39%), and gait disturbance (8/28, 32%). Radiographically, lesions most commonly involved the mammillary region (18/23, 78%), the tuberal/infundibulum region (13/23, 57%), and the preoptic/lamina terminalis region (12/23, 52%), with a mean diameter of 2.5 ± 1.4 cm (range 0.8-7 cm) at presentation. Acute hemorrhage was identified in 96% (23/24) of patients on presentation, with 96% (23/24) intraparenchymal and 29% (7/24) intraventricular. Of 24 patients who were managed surgically, gross-total resection (GTR) was achieved in 88% (21/24) of cases. There were no reports of perioperative infarction or mortality. With a mean follow-up period of 41 months (range 0.5-309 months), 77% (20/26) of patients experienced functional improvement, while 12% (3/26) had no change, and 12% (3/26) experienced increased disability. In our cohort of 12 patients, 83% (10/12) continued to report symptoms at the last follow-up (mean 4.8 years, range 0.1-25.7 years). However, there was a significant improvement in mRS score noted after surgery (mean 1.4 vs 3.1, p = 0.0026) and a trend toward improvement in GOSE score (mean 6.3 vs 5.1, p = 0.09).

CONCLUSIONS

Hemorrhage from HCMs can cause a symptomatic mass effect on adjacent eloquent structures. While patients are unlikely to be deficit free following surgery, GTR allows for functional improvement and reduces recurrent hemorrhage rates. Microsurgery remains a viable option for symptomatic HCMs in experienced hands.

Contralateral Interhemispheric Transcallosal Approach for Thalamic Cystic Cavernous Malformation

A 42-year-old man presented with a headache and right hemiparesis and was found to have a cystic mass with a calcified mural nodule in the left thalamus. Because the thalamus is surrounded by vital neurovascular structures, the surgical approach to thalamic lesions can be challenging. We decided to remove the mass for decompression and pathological diagnosis. The mass was removed through a contralateral interhemispheric transcallosal transchoroidal approach with less retraction and parenchymal injury than other approaches to avoid brain retraction and cortical injury. The pathological diagnosis was cavernous malformation. Temporary worsening of the preoperative hemiparesis was recovered over two months following surgery. Tolerable thalamic pain syndrome remained. Here, we report a rare case of thalamic cavernous malformation with a favorable outcome through a contralateral surgical approach.

Paramedian Supracerebellar Infratentorial Approach for Pontine Cavernoma: 2-Dimensional Operative Video

We describe the case of a 26-yr-old male who presented with headaches, dizziness, and left hemi-hypoesthesia in addition to being COVID-19 positive. The patient was found to have a large hemorrhage in the right dorsolateral pons that was found to be due to a pontine cavernous malformation. The patient underwent a right-sided paramedian supracerebellar infratentorial approach for resection of this lesion with preservation of the developmental venous anomaly. We present the operative video with a specific focus on approach selection, anatomic illustrations, and technical nuances. The literature on the timing of brainstem cavernoma surgery is reviewed.1-4 The patient's postoperative clinical course and postoperative imaging are reviewed. The patient gave informed consent for the procedure and verbal consent for being part of this submission and the publication of their image.

Microsurgical management of midbrain cavernous malformations: does lesion depth influence the outcome?

Background

The purpose of this study was to clarify whether the intrinsic depth of midbrain cavernous malformations (MCMs) influenced the surgical outcome.

Methods

The authors conducted a retrospective study of 76 consecutive patients who underwent microsurgical resection of a MCM. The vascular lesions were categorized into 4 distinct groups based on how these lesions had altered the brainstem surface. Additionally, it was verified whether the actual aspect of the brainstem surface could be predicted only by evaluating the pertinent preoperative MRI slices. Clinical outcome was assessed by determining the modified Rankin Scale Score (mRS) before and after surgery.

Results

Twenty-three MCMs (30.3%) were located deeply within the midbrain. The overlying midbrain surface appeared to be normal (group nl). In 33 patients (43.4%), the midbrain surface showed only a yellowish discoloration (group yw). In another 14 individuals (18.4%), the midbrain surface was distorted by the underlying MCM and bulging out while the vascular lesion still remained covered by a thin parenchymal layer (group bg). In the smallest group comprising 6 patients (7.9%), the exophytic MCM had disrupted the midbrain surface and was clearly visible at microsurgical exposure (group ex). The mean mRS decreased in the group nl from 1.43 preoperatively to 0.61 at follow-up.

Conclusion

This study demonstrates in a large patient population that a deep intrinsic MCM location is not necessarily associated with an unfavorable clinical outcome after microsurgical lesionectomy. Predicting the aspect of the midbrain surface by evaluating preoperative MR images alone was not sufficiently reliable.

Recurrent brainstem cavernous malformations following primary resection: blind spots, fine lines, and the right-angle method

OBJECTIVE

Proximity of brainstem cavernous malformations (BSCMs) to tracts and cranial nerve nuclei make it costly to transgress normal tissue in accessing the lesion or disrupting normal tissue adjacent to the lesion in the separation plane. This interplay between tissue sensitivity and extreme eloquence makes it difficult to avoid leaving a remnant on occasion. Recurrences require operative intervention, which may increase morbidity, lengthen recovery, and add to overall costs. An approximately 20-year experience with patients with recurrent BSCM lesions following primary microsurgical resection was reviewed.

METHODS

A prospectively maintained database of 802 patients who underwent microsurgical resection of cerebral cavernous malformations during 1997-2018 was queried to identify 213 patients with BSCMs. A retrospective chart review was conducted for patients with recurrent BSCM after primary resection who required a second surgery.

RESULTS

Fourteen of 213 patients (6.6%) underwent repeat resection for recurrent BSCM. Thirty-four hemorrhagic events were observed among these 14 patients over 576 patient-years (recurrent hemorrhage rate, 5.9% per year; median discrete hemorrhagic events, 2; median time to rehemorrhage, 897 days). BSCM occurred in the pons in 10 cases, midbrain in 2 cases, and medulla in 2 cases. A blind spot in the operative corridor was the most common cause of residual BSCM (9 patients). All recurrent BSCMs were removed completely, although 2 patients each required 2 operations to treat recurrence. Twelve patients had unchanged or improved modified Rankin Scale scores at last clinical evaluation compared with admission, and 2 patients had worse scores. Recurrence was more common among patients who were operated on in the first versus the second half of the series (8.5% vs 4.7%).

CONCLUSIONS

The 6.6% rate of BSCM recurrence requiring reoperation reflects the fine lines between complete resection and recurrence and between safe and harmful surgery. The detection of remnants is difficult postoperatively and remains so even at 6 months when the resection bed has healed. The 5.9% annual hemorrhage risk associated with recurrent BSCM in this experience is consistent with that reported for unoperated BSCMs. The right-angle method helps to anticipate blind spots and meticulously inspect the resection cavity for residual BSCM during surgery. A low percentage of recurrent BSCM (5%-10%) ensures ongoing effort toward an acceptable balance of safety and completeness.

Functional DTI tractography in brainstem cavernoma surgery

OBJECTIVE

Surgical resection of brainstem cavernomas is associated with high postoperative morbidity due to the density of local vulnerable structures. Classical mapping of pathways by diffusion tensor imaging (DTI) has proven to be unspecific and confusing in many cases. In the current study, the authors aimed to establish a more reliable, specific, and objective method for somatotopic visualization of the descending motor pathways with navigated transcranial magnetic stimulation (nTMS)–based DTI fiber tracking.

METHODS

Twenty-one patients with brainstem cavernomas were examined with nTMS prior to surgery. The resting motor threshold (RMT) and cortical representation areas of hand, leg, and facial function were determined on both hemispheres. Motor evoked potential (MEP)–positive stimulation spots were then set as seed points for tractography. Somatotopic fiber tracking was performed at a fractional anisotropy (FA) value of 75% of the individual FA threshold.

RESULTS

Mapping of the motor cortex and tract reconstruction for hand, leg, and facial function was successful in all patients. The somatotopy of corticospinal and corticonuclear tracts was also clearly depicted on the brainstem level. Higher preoperative RMT values were associated with a postoperative motor deficit (p < 0.05) and correlated with a lower FA threshold (p < 0.05), revealing structural impairment of the corticospinal tract (CST) prior to surgery. In patients with a new deficit, the distance between the lesion and CST was below 1 mm.

CONCLUSIONS

nTMS-based fiber tracking enables objective somatotopic tract visualization on the brainstem level and provides a valuable instrument for preoperative planning, intraoperative orientation, and individual risk stratification. nTMS may thus increase the safety of surgical resection of brainstem cavernomas.

Supracerebellar Infratentorial Infratrochlear Trans-Quadrangular Lobule Approach to Pontine Cavernous Malformations

BACKGROUND

Brainstem cavernous malformations with symptomatic hemorrhage have a poor natural history. Those without a pial or ependymal presentation are often observed given the morbidity of resection. Surgical removal is considered only in patients with accessible lesions that have repeated symptomatic hemorrhagic.

OBJECTIVE

To describe a novel supracerebellar infratentorial infratrochlear trans-quadrangular lobule approach to safely resect lesions in the upper pons.

METHODS

We use a hybrid paramedian/lateral suboccipital craniotomy in the gravity-dependent supine position. Opening the cerebellomesencephalic fissure over the tentorial surface of the cerebellum brings the trochlear nerve, branches of the superior cerebellar artery, and the quadrangular lobule of the cerebellum into view. Removal of small a portion of the quadrangular lobule defines an entry point on the superomedial aspect of the middle cerebellar peduncle, and a surgical trajectory aimed superior to inferior.

RESULTS

A total of 6 patients underwent this approach. All presented with symptomatic hemorrhage and all cavernous malformations were completely resected. Five patients were improved or unchanged with modified Rankin scale scores of 1 or 2.

CONCLUSION

The trans-quadrangular lobule approach allows safe resection of upper pontine cavernous malformations along a superior to inferior trajectory.

Endoscopic Surgery for Supratentorial Deep Cavernous Malformation Adjacent to Cortical Spinal Tract: Preliminary Experience and Technical Note

In this study, we aimed to introduce a technical note and to explore the efficacy of endoscopic surgery combined with diffusion tensor imaging (DTI) navigation for supratentorial deep cerebral cavernous malformations (CCM). A prospectively maintained database of CCM patients was reviewed to identify all CCM patients treated by endoscopic surgery. The sagittal T1-weighted anatomical magnetic resonance imaging (MRI) and DTI were acquired before surgery. Endoscopic surgery was planned and performed based on preoperative DTI images and intraoperative DTI navigation. All patients were followed up more than 6 months. Motor function deficit and modified Rankin scale (mRS) scores were documented on follow-up. A final mRS score of 0–2 was considered a good outcome, and a final mRS score >2 was considered a poor outcome. Second DTI and 3DT1 were performed at 3 months after surgery. We tracked the ipsilateral corticospinal tract (CST) on pre- and postoperative DTI images. The overall mean FA values and the number of fibers of tracked CST were compared on pre- and postoperative DTI images. Risk factors associated with motor deficits and poor outcomes were analyzed. Seven patients with deep CCM and treated by endoscopic surgery were enrolled in this study. The mean value of preoperative mRS was 1.5 ± 0.98, but that score recovered to 0.86 ± 1.22 3 months later. The mRS scores were improved significantly according to statistical analysis (p = 0.012). According to the Spearman non-parametric test, only the fiber number of ipsilateral CST on postoperative DTI was significantly associated with muscle strength 6 months after surgery (p = 0.032). Compared with preoperative CST characteristics on DTI, the change of FA value (p = 0.289) and fiber number (p = 0.289) of ipsilateral CST on postoperative DTI was not significant It meant that the CST was protected during endoscopic surgery. Endoscopic surgery based on DTI navigation might be an effective method to protect fiber tracts in supratentorial deep CCM patients and improve long-term outcomes. However, more studies and cases are needed to confirm our findings.

Mortality in Patients with Brainstem Cavernous Malformations

OBJECTIVE

Brainstem cavernous malformations (BSCM)-associated mortality has been reported up to 20% in patients managed conservatively, whereas postoperative mortality rates range from 0 to 1.9%. Our aim was to analyze the actual risk and causes of BSCM-associated mortality in patients managed conservatively and surgically based on our own patient cohort and a systematic literature review.

METHODS

Observational, retrospective single-center study encompassing all patients with BSCM that presented to our institution between 2006 and 2018. In addition, a systematic review was performed on all studies encompassing patients with BSCM managed conservatively and surgically.

RESULTS

Of 118 patients, 54 were treated conservatively (961.0 person years follow-up in total). No BSCM-associated mortality was observed in our conservatively as well as surgically managed patient cohort. Our systematic literature review and analysis revealed an overall BSCM-associated mortality rate of 2.3% (95% CI: 1.6-3.3) in 22 studies comprising 1,251 patients managed conservatively and of 1.3% (95% CI: 0.9-1.7) in 99 studies comprising 3,275 patients with BSCM treated surgically.

CONCLUSION

The BSCM-associated mortality rate in patients managed conservatively is almost as low as in patients treated surgically and much lower than in frequently cited reports, most probably due to the good selection nowadays in regard to surgery.

Gamma Knife Radiosurgery for Cavernous Malformations of Basal Ganglia and Thalamus: A Retrospective Study of 53 Patients

INTRODUCTION

Gamma Knife radiosurgery (GKRS) has been used to treat cavernous malformations (CMs) located in basal ganglia and thalamus. However, previous reports are limited by small patient population.

METHODS

We retrospectively reviewed the clinical and radiological data of 53 patients with CMs of basal ganglia and thalamus who underwent GKRS at West China Hospital between May 2009 and July 2018. All patients suffered at least once bleeding before GKRS. The mean volume of these lesions was 1.77 cm3, and the mean marginal dose was 13.2 Gy. After treatment, patients were followed to determine the change in symptom and hemorrhage event.

RESULTS

The mean follow-up period was 52.1 months (6.2-104.3 months). The calculated annual hemorrhage rate (AHR) was 48.5% prior to GKRS and 3.0% after treatment (p < 0.001). The Kaplan-Meier analysis revealed that 2-, 3-, and 5-year hemorrhage-free survival were 88, 80.9, and 80.9%, respectively. Preexisting symptoms were resolved in 11 patients, improved in 14, and stable in 5. Only 2 patients (3.8%) developed new neurological deficit.

CONCLUSION

Our study suggests that AHR after GKRS was comparable to the recorded AHR of natural history (3.1-4.1%) in previous studies. GKRS is a safe and effective treatment modality for CMs of basal ganglia and thalamus. Considering the relative insufficient understanding of natural history of CMs, future study warrants longer follow-up.

Neurological outcomes of untreated brainstem cavernous malformations in a prospective observational cohort and literature review

Background

Haemorrhages of brainstem cavernous malformations (CMs) can lead to neurological deficits, the natural history of which is uncertain. The study aimed to evaluate the neurological outcomes of untreated brainstem CMs and to identify the adverse factors associated with worsened outcomes.

Methods

From 2009 to 2015, 698 patients (321 women) with brainstem CMs were entered into the prospective cohort after excluding patients lost to follow-up (n=43). All patients were registered, clinical data were collected and scheduled follow-up was performed.

Results

After a median follow-up of 60.9 months, prospective haemorrhages occurred in 167 patients (23.9%). The mean modified Rankin Scale scores at enrolment and at censoring time were 1.6 and 1.2. Neurological status was improved, unchanged and worsened in 334 (47.9%), 293 (42.0%) and 71 (10.2%) patients, respectively; 233 (33.4%) recovered to normal levels. Lesions crossing the axial midpoint (relative risk (RR) 2.325, p=0.003) and developmental venous anomaly (DVA) (RR 1.776, p=0.036) were independently significantly related to worsened outcomes. The percentage of worsened outcomes was 5.3% (18 of 337) in low-risk patients (neither DVA nor crossing the axial point) and increased to 26.0% (13 of 50) in high-risk patients (with both DVA and crossing the axial point). The percentage of worsened outcomes significantly increased as the number of prospective haemorrhages increased (from 1.5% (8 of 531, if 0 prospective ictus) to 37.5% (48 of 128, if 1 ictus) and 38.5% (15 of 39, if >1 ictus)).

Conclusions

The neurological outcomes of untreated brainstem CMs were improved/unchanged in majority of patients (89.8%) with a fatality rate of 1.7% in our cohort, which seemed to be favourable. Radiological features significantly predicted worsened outcomes. Our results provide evidence for clinical consultation and individualised treatment. The referral bias of our cohort was underlined.

Utility of a Quantitative Approach Using Diffusion Tensor Imaging for Prognostication Regarding Motor and Functional Outcomes in Patients With Surgically Resected Deep Intracranial Cavernous Malformations

BACKGROUND

Resection of deep intracranial cavernous malformations (CMs) is associated with a higher risk of neurological deterioration and uncertainty regarding clinical outcomes.

OBJECTIVE

To examine diffusion tractography imaging (DTI) data evaluating the corticospinal tract (CST) in relation to motor and functional outcomes in patients with surgically resected deep CMs.

METHODS

Perilesional CST was characterized as disrupted, displaced, or normal. Mean fractional anisotropy (FA) values were obtained for whole ipsilateral CST and in 3 regions: subcortical (proximal), perilesional, and distally. Mean FA values in anatomically equivalent regions in the contralateral CST were obtained. Clinical and radiological data were collected independently. Multivariable regression analysis was used for statistical analysis.

RESULTS

A total of 18 patients [brainstem (15) and thalamus/basal ganglia (3); median follow-up: 270 d] were identified over 2 yr. The CST was identified preoperatively as disrupted (6), displaced (8), and normal (4). Five of 6 patients with disruption had weakness. Higher preoperative mean FA values for distal ipsilateral CST segment were associated with better preoperative lower (P < .001), upper limb (P = .004), postoperative lower (P = .005), and upper limb (P < .001) motor examination. Preoperative mean FA values for distal ipsilateral CST segment (P = .001) and contralateral perilesional CST segment (P < .001) were negatively associated with postoperative modified Rankin scale scores.

CONCLUSION

Lower preoperative mean FA values for overall and defined CST segments corresponded to worse patient pre- and postoperative motor examination and/or functional status. FA value for the distal ipsilateral CST segment has prognostic potential with respect to clinical outcomes.

Treatments and outcomes of untreated cerebral cavernous malformations in China: study protocol of a nationwide multicentre prospective cohort study

INTRODUCTION

The treatment decision and long-term outcomes of previously untreated cerebral cavernous malformation (U-CCM) are still controversial. Therefore, we are conducting a nationwide multicentre prospective registry study in China to determine the natural history and effect of surgical treatment on long-term outcomes in Chinese people with U-CCM.

METHODS AND ANALYSIS

This study was started on 1 January 2018 and is currently ongoing. It is a cohort follow-up study across a 5-year period. Patients will be followed up for at least 3 years after inception. Patients with U-CCM will be enrolled from 24 Grade III, level A hospitals distributed all over China. The cohort size is estimated to be 1200 patients. Patients are registered in surgically treated group and conservatively treated group. Clinical characteristics, radiology information and laboratory data are prospectively collected using an electronic case report form through an electronic data capture system. The primary outcome of this study is poor clinical outcome at the last follow-up (modified Rankin Scale score >2 lasting at least 1 year). The secondary outcome includes symptomatic haemorrhage, drug refractory epilepsy, focal neurological deficits, morbidity and all-cause mortality during follow-up. Univariate and multivariate regression analysis will be performed to determine the risk factors for poor outcomes in all patients, and to estimate the effect of surgery. Life tables, Kaplan-Meier estimates, log-rank test and proportional hazards Cox regression will be used to analyse the follow-up data of conservatively treated patients to determine the natural history of U-CCM. Initial presentation and location of U-CCM are prespecified subgroup factors.

ETHICS AND DISSEMINATION

The study protocol and informed consent form have been reviewed and approved by the Research Ethical Committee of First Affiliated Hospital of Fujian Medical University (FAHFMU-2018-003).Written informed consent will be obtained from each adult participant or from the guardian of each paediatric participant. The final results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03467295.

Transient Palatal Tremor and Action Induced Foot and Leg Dystonia due to Hypertrophic Olivary Degeneration: a Case Report

Hypertrophic olivary degeneration (HOD) is a rare phenomenon that occurs after various insults to the Guillain-mollaret triangle (GMT). HOD is unique because the degeneration of inferior olivary nucleus becomes hypertrophic rather than atrophic. In this study, a 31-year-old woman developed HOD after pontine cavernoma surgery had been performed. The clinical manifestation was involuntary intorsion of right lower extremity during walking, which has not been reported in the literature. The woman also presented with palatal tremor, the most classic symptom of HOD. HOD's imaging trait include olive hypertrophy with increased T2 signal intensity on MRI, which are corresponding to the pathological findings. HOD is a self-limiting disease and excessive treatments are unnecessary.

Surgery for Brainstem Cavernous Malformations: Association between Preoperative Grade and Postoperative Quality of Life

BACKGROUND

Brainstem cavernous malformations (BSCMs) are associated with substantial neurologic morbidity, but the literature on quality of life (QoL) after surgical treatment is limited. There is a need for validating the clinical utility of current grading scales for cavernous malformations.

OBJECTIVE

To assess outcome of surgery for BSCMs and validate how outcome is associated with current grading scales for cavernous malformations.

METHODS

We retrospectively reviewed a single-surgeon series of patients with BSCM treated surgically during a 10-yr period. Outcome was categorized according to modified Rankin Scale (mRS), and QoL was assessed by interviewing patients using Short Form 36 (SF-36) Health Survey and comparing results with the normative population. The mRS and QoL were correlated with the Lawton BSCM grading scale and with the Zabramski classification of cavernous malformations.

RESULTS

The study included 22 patients (12 males and 10 females; median age 58 yr). No mortality related to the BSCM surgery occurred, and none were in vegetative state. In SF-36, 70% of patients reported a physical and mental functioning noninferior compared to the general population of comparative age and gender group. There was a significant positive correlation between the Lawton BSCM grading and the postoperative mRS score and QoL.

CONCLUSION

Outcome of surgery for BSCM was good, as assessed by mRS and QoL. The Lawton grading scale for BSCMs correlated significantly with the postoperative mRS score and QoL, suggesting this grading scale may become a useful clinical tool for treatment prognostication at the individual level.

Natural history of incidentally diagnosed brainstem cavernous malformations in a prospective observational cohort

There was a lack of natural history of incidental brainstem cavernous malformations (CMs), hemorrhage of which would lead to severe neuropathies. The study aimed to evaluate the prospective hemorrhage rate and neurological outcome of the disease. This prospective cohort included patients with incidental brainstem CMs referred to our institute from 2009 to 2015. The diagnosis was confirmed based on the patients' complain, physical examination, and radiographic evidence. Clinical data were collected, scheduled follow-up was performed, and the independent risk factors were identified by multivariate analysis. This cohort included 48 patients (22 female, 45.8%). The median follow-up duration was 60.7 months, and 13 prospective hemorrhages occurred within 244.0 patient-years yielding an annual hemorrhage rate of 5.3%. The hemorrhage-free survival at 1 and 5 years was 91.6% and 80.6%. Age ≥ 55 years (hazard ratio (HR) = 8.59, p = 0.003), lesion size (per 1-mm increase) (HR = 3.55, p = 0.041), developmental venous anomaly (HR = 10.28, p = 0.017), and perilesional edema (HR = 4.90, p = 0.043) were independent risk factors for hemorrhage. Seven patients (14.6%) received surgical resection, and the other 41 patients remained under observation. Neurological function was improved in 22 patients (45.8%), unchanged in 19 (39.6%), and worsened in 7 (14.6%). Prospective hemorrhage (odds ratio = 14.95, p = 0.037) was the only independent risk factor for worsened outcomes. The natural history of incidental brainstem CMs seemed to be acceptable with improved/unchanged outcomes in most patients (85.4%). These results improved our understanding of the disease, and the future study of a large cohort was required to verify our findings.

Emergency surgery for brainstem cavernoma haemorrhage with severe neurological presentation. Is it indicated and worthwhile?

Background: Brainstem Cavernoma (BSCM) haemorrhage is a complex condition, especially when patients present rapid neurological deterioration. Traditionally, these patients were initially treated by non-interventional means. Surgery was generally reserved for cases who presented a 'benign' evolution in a subacute/delayed fashion. Timing of surgery remains controversial. Since rebleeding is frequent and carries a high mortality, many of these patients do not tolerate this approach. Urgent/emergent surgery may be indicated and lifesaving.Methods: A single center experience is reported in which an aggressive approach was used with urgent/emergency surgery carried out on patients with BSCM haemorrhage and rapid neurological deterioration, ventilatory impairment and/or coma. A review of 5 consecutive cases where urgent/emergent surgery was performed is presented. The pre-operative status, pre- and post-operative examinations, surgical approach and neurological residual deficits/outcomes are reported.Results: Four females and one male with ages ranging from 36 to 66 years with rapid neurological deterioration, ventilatory impairment and/or coma were operated between 2011 and 2018. Favourable outcomes were observed with a modified Rankin Scale varying from 1 to 4. Cranial nerve deficits as well as motor and sensitive deficits were observed but all the patients recovered cognitive integrity.Conclusions: Our small series reveals an acceptable outcome with ultra-early surgery. This approach appears to be a valid option when there is rapid neurological deterioration, respiratory impairment and/or early onset coma. However, further studies are required to elucidate the optimal strategy.

Cavernous malformation hemorrhage due to trans-mural pressure alterations after cerebrospinal fluid diversion: a case report

BACKGROUND

Cavernous malformations are rare cerebral pseudo-vascular lesions with annualized bleeding rates of 0.5-3% in most studies. Of the various explored risk factors for bleeding to date, only prior hemorrhage has shown significant correlation.

CASE PRESENTATION

In this case, we describe a 65-year old man with a peri-ventricular atrial cavernous malformation that hemorrhaged after CSF diversion via ventriculoperitoneal shunting. Serial imaging showed that bleeding continued until the shunt was revised with a programmable valve set at maximum resistance with the addition of a gravitational unit, thereby lowering the trans-mural pressure differential across the cavernous malformation.

CONCLUSIONS

Given that other vascular lesions are subject to hemorrhage from alterations in trans-mural pressure dynamics, we hypothesize that cavernous malformations are similarly affected by trans-mural pressure gradients as they are composed of primitive vascular elements. This hypothesis is corroborated by the temporal correlation of interventions, imaging, and exam findings in the present case, and suggests a potentially important risk factor for hemorrhage in CM patients that affects prognostication and management.

Brainstem cavernous malformations - no longer a forbidden territory? A systemic review of recent literature

BACKGROUND

Due to its eloquent location and potentially devastating neurological consequences, the management of brainstem cavernous malformations (CCMs) attracts considerable debate. There is currently a paucity of Level 1 evidence for their management. The aim of this literature review is to explore the current evidence on the risk-benefit profile of different management options.

METHODS

A systemic literature search, following the PRISMA algorithm was performed on publications between 2010 and 2018 using the Pubmed database, with the relevant keywords. Only English articles were included. Articles focusing on spinal CCMs and studies with less than 30 participants were excluded.

RESULTS

A total of 222 search results were reviewed and after removal of duplicates and screening of abstracts, 28 clinical papers comprising 30 or more brainstem CCM cases were included in the study. The heterogeneity of the publications precluded a formal meta-analysis of results. The general consensus is that for CCMs presenting with severe symptoms and/or multiple haemorrhages that reach an accessible pial surface, surgery is considered to be the gold-standard treatment, with some authors suggesting the optimal timing to be within two to six weeks of ictus. For those patients with multiple, deep-seated CCM related haemorrhages that do not reach the pial surface, stereotactic radiosurgery (SRS) can be considered. Conservative treatment is generally considered in incidental cases. Management of brainstem cavernomas of other categories still remains controversial.

CONCLUSIONS

Due to their highly eloquent location, brainstem CCMs are challenging lesions to manage. Management must be balanced by the risk-benefit profile and tailored to the individual patients and their treating clinicians. This review provides a comprehensive reference considering all treatment options and provides a basis for evidence-based patient counselling.

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.

Transient Aphasia Following Resection of a Thalamic Cavernous Malformation

BACKGROUND

The thalamus has a demonstrated role in language, particularly through its connectivity to frontal language cortices.

CASE DESCRIPTION

A 59-year-old man with transient mixed aphasia following resection of a left-sided thalamic cavernous malformation is reported. No operative complications were encountered, and there was no surgical contact with cortical language areas. The patient recovered full language function within a week postoperatively.

CONCLUSIONS

The role of thalamic nuclei in language processes and other reports of transient thalamic aphasia are reviewed.

Surgical managements and patient outcomes after severe hemorrhagic events from brainstem cavernous malformations

To evaluate the surgical outcomes and predictors and the impact of surgical timing of patients who suffered a severe hemorrhagic event from brainstem cavernous malformations (CMs). The clinical data of all patients who underwent surgical treatment after a severe bleeding ictus from brainstem CMs between 2011 and 2017 were retrospectively reviewed. The study population consisted of 61 surgical patients (40, 65.6% female). Surgical times of < 3 weeks, ≥ 3-8 weeks, and > 8 weeks since the last bleeding ictus were observed in 23 (37.7%), 24 (39.3%), and 14 (23.0%) patients, respectively. The mean modified Rankin scale (mRS) score evaluated on admission was 4.2. With a mean follow-up of 39.8 months, 39 patients (63.9%) had a favorable outcome (mRS ≤ 2), and the mean mRS score was 2.3. The logistic regression analysis identified age, having disrupted consciousness and/or respiration, and time to surgery from last hemorrhage as significant predictors of long-term outcome. In particular, patients with surgery performed during the acute period (< 3 weeks, P = 0.06) or chronic period (> 8 weeks, P = 0.01) tended to have poor outcomes when compared with those with surgery during the subacute period (≥ 3-8 weeks). Favorable neurological outcomes can be achieved in patients who were surgically treated after a severe hemorrhagic ictus from brainstem CMs, and operation during subacute hemorrhage (≥ 3-8 weeks) could benefit these patients.

Cavernous Malformations in and Around the Third Ventricle: Indications, Approaches, and Outcomes

BACKGROUND

Cavernous malformations in structures in and around the third ventricle are a challenging conceptual and surgical problem. No consensus exists on the ideal approach to such lesions.

OBJECTIVE

To perform a retrospective review of our institutional database to identify and evaluate approaches used to treat cavernous malformations located in and around the third ventricle.

METHODS

Information was extracted regarding lesion size and location, extent of resection, time to last follow-up, surgical approach, presenting symptoms, preoperative and postoperative neurological status, and specific approach-related morbidity.

RESULTS

All 39 neurosurgical operations (in 36 patients) were either an anterior interhemispheric (AIH) (44%, 17/39) or a supracerebellar infratentorial (SCIT) (56%, 22/39) approach. Gross-total resection was achieved in 23 of 39 procedures (59%), a near-total resection in 1 (3%), and subtotal resection in 15 (38%). For the 31 patients with at least 3 mo of follow-up, the mean modified Rankin Scale (mRS) score was 1.5. Of the 31 patients, 25 (81%) had an mRS score of 0 to 2, 4 had a mRS score of 3 (13%), and 1 each had a mRS score of 4 (3%) or 5 (3%).

CONCLUSION

Most approaches to cavernous malformations in and around the third ventricle treated at our institution have been either an AIH or a SCIT approach. The AIH approach was used for lesions involving the lateral wall of the third ventricle or the midline third ventricular floor, whereas the SCIT approach was used for lesions extending from the third ventricle into the dorsolateral midbrain, with acceptable clinical results.

Surgical treatment of pontine cavernous malformations via subtemporal transtentorial and intradural anterior transpetrosal approaches

The aim of this study was to report our surgical experience on resection of the pontine cavernous malformations (CMs) via subtemporal transtentorial approach (STTA) and intradural anterior transpetrosal approach (ATPA). Clinical data were retrospectively reviewed in 61 patients with pontine CMs that were surgically treated by the STTA and the intradural ATPA. The surgical procedures, complications, and outcomes were analyzed. The study consists of 61 patients with a total of 61 pontine CMs. Other than 4 lesions located medially in the pons, all CMs were in the lateral pons with a left or right lateral epicenter (the left/right ratio was 22/35). Totally, 11 patients (18.0%) with lesions located in the upper pons were treated by the STTA, and 50 patients (82.0%) with lesions involving the lower pons were treated by the intradural ATPA. Postoperatively, the complete resection was achieved in 58 patients (95.1%) and incomplete resection in 3 patients (4.9%). Twenty-seven patients (44.3%) suffered from a new or worsened neurological deficit in the immediate postoperative period, and 8 patients (13.1%) encountered a non-neural complication, including rebleeding, cerebrospinal fluid leak, intracranial infection, and pulmonary infection, and 3 patients had contusion of temporal lobe. With a mean follow-up of 54.2 months, the patients' neurological condition had improved in 43 cases (71.6%), not changed in 10 cases (16.7%), and worsened in 7 cases (11.7%), respectively. The Karnofsky Performance Scale (KPS) score evaluated at the last time for per patient was significantly better than their baseline status (t = 6.677, p < 0.001). However, 21 patients (35.0%) suffered from a new or worsened persistent postoperative deficit. The lateral and anterolateral pons can be exposed well by the subtemporal transtentorial and intradural anterior transpetrosal approaches. Lesions of CMs located in the lateral pons, including ventrolateral and dorsolateral pons, could be totally removed by these two lateral approaches with an acceptable surgical morbidity.

Microsurgical laser resection of brainstem cavernous malformations

This operative technique video demonstrates laser microsurgery for brainstem cavernous malformations (CMs). In case 1 we demonstrate CO₂ laser microsurgery for a symptomatic pontine CM using far lateral craniotomy and olivary zone entry. Case 2 demonstrates the subtemporal approach and removal of a paratrigeminal CM, and case 3 is a dorsal midbrain CM. We illustrate several advantages of laser microsurgery including improved visualization in narrow corridors, precise cutting with reduced thermal damage, and effective sealing of small vessels. Over the past decade at Stanford University School of Medicine, over 120 brainstem CMs have been removed using laser microsurgery with good results.

The video can be found here: https://youtu.be/DwwqWGv_vzo.

Paramedian contralateral supracerebellar infratentorial approach to thalamic cavernous malformation

Cavernous malformations (CVMs) located in the thalamus are uncommon. However, they pose difficulties for resection because of their close proximity to eloquent areas of the brain and vascular structures, and all surgical corridors to access them are narrow. In this video, we report the case of a 19-year-old woman who presented with a long-standing history of right hemiparesis with recent deterioration. MRI revealed a large CVM located in the left thalamus, with signs of recent hemorrhage extending to the left cerebral peduncle. Resection was achieved with a paramedian contralateral supracerebellar infratentorial approach in a semisitting position, with an uneventful postoperative course. The video can be found here: https://youtu.be/Arvu52FkHOE.

Usefulness of the anterior transpetrosal approach for pontine cavernous malformations

Surgical resection of pontine cavernous malformation remains a particularly formidable challenge. We report the surgical outcome of eight cases with pontine cavernous malformations operated using the anterior transpetrosal approach. All cases presented with neurological deficits caused by hemorrhage before surgery. Gross-total removal was achieved in all cases without any postoperative complication such as worsening of facial nerve palsy, ocular movement disorder, or hemiplegia. A small incision of the pons with multidirectional dissection is the most important factor for minimizing postoperative neurological deficits, so resection of a pontine cavernous malformation via this approach can be an alternative better option.

The video can be found here: https://youtu.be/2Q2CUhBbo28.

Microsurgical Management of Midbrain Cavernous Malformations: Predictors of Outcome and Lesion Classification in 72 Patients

BACKGROUND

Due to the complex segmental organization of the brainstem, it is preferable to study midbrain cavernous malformations (MCMs) separately from pontine and medullary lesions.

OBJECTIVE

To evaluate clinical results after microsurgical removal of MCMs, assess predictors for outcome and introduce a topographical classification of MCMs.

METHODS

A retrospective study was conducted on consecutive patients who underwent MCM resection. Clinical parameters before and after surgery, morphological CM features, surgical approaches and outcomes were analyzed. MCMs were classified according to their exact location within the midbrain and their axial and sagittal extension.

RESULTS

The authors reviewed 72 patients (35 male). Lesions varied in size between 4 and 55 mm. The vast majority of patients benefited from surgery. The mean modified Rankin Scale (mRS) decreased significantly from 1.6 at admission to 1.3 at discharge and to 0.7 at follow-up (6-247 mo postoperatively). Five patients (6.9%) suffered from delayed hypertrophic olivary degeneration as visualized on magnetic resonance imaging. One male suffered from early postoperative re-bleeding that required surgical hematoma evacuation. There were no severe long tract impairment or other disabling complications, no delayed re-bleedings, and no surgical mortality.

CONCLUSION

We present a new topographic classification of MCMs that may be useful for predicting the occurrence of postoperative eye movement disorders. Other predictors of persistent oculomotor disturbances are time interval between onset of symptoms and surgery, and patient's age over 40 yr. Early surgery is recommendable in patients with oculomotor disturbances. MCM size over 18 mm, patient age over 40 yr, and poor mRS at admission are important predictors for the long-term outcome.

Quantification of Microsurgical Anatomy in Three-Dimensional Model: Transfrontal Approach for Anterior Portion of the Thalamus

The thalamus located in the deep site of cerebrum with the risk of internal capsule injury during operation. The purpose of this study was to compare the anatomy for exposure and injury using simulative surgical corridor of 3-dimensional model. The 3-dimensional anatomy model of thalamus in cerebrum was created based on magnetic resonance imaging performed for 15 patients with trigeminal neuralgia. The midpoint of line between anterior edge and top of thalamus was the target exposed. Axis connecting the target with the anterior edge and top of caudate head was used to outline the cylinder, respectively, simulating surgical corridors 1 and 2 of transfrontal approach. Cerebral tissues involved in the corridors were observed, measured, and compared. Incision of cortex was made on the anterior portion of inferior frontal gyrus through corridor 1 and middle frontal gyrus through corridor 2. Both of the 2 corridors passed the caudate nucleus, the anterior limb and genu of internal capsule, ultimately reached the upper anterior portion of thalamus. The volumes of white matter, caudate head, and thalamus in the corridor 1 were more than those in corridor 2. Conversely, the volumes of cortex, internal capsule in corridor 2 were more than those in corridor 1. In conclusion, surgical anatomy-specific volume is helpful to postulate the intraoperative injury of transfrontal approach exposing anterior portion of the thalamus. The detailed information in the quantification of microsurgical anatomy will be used to develop minimally invasive operation.

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

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