Seizure characteristics and control after microsurgical resection of supratentorial cerebral cavernous malformations

Microsurgical removal of supratentorial and cerebellar cavernous malformations: what has changed? A single institution experience

BACKGROUND

Features associated with a safe surgical resection of cerebral cavernous malformations (CMs) are still not clear and what is needed to achieve this target has not been defined yet.

METHODS

Clinical presentation, radiological features and anatomical locations were assessed for patients operated on from January 2008 to January 2018 for supratentorial and cerebellar cavernomas. Supratentorial CMs were divided into 3 subgroups (non-critical vs. superficial critical vs. deep critical). The clinical outcome was assessed through modified Rankin Scale (mRS) and was divided into favorable (mRS 0-1) and unfavorable (mRS ≥ 2). Post-operative epilepsy was classified according to the Maraire Scale.

RESULTS

A total of 144 were considered eligible for the current study. At 6 months follow-up the clinical outcome was excellent for patients with cerebellar or lobar CMs in non-critical areas (mRS ≤ 1: 91.1 %) and for patients with superficial CMs in critical areas (mRS ≤ 1: 92.3 %). Patients with deep-seated suprantentorial CMs showed a favorable outcome in 76.9 %. As for epilepsy 58.5 % of patients presenting with a history of epilepsy were free from seizures and without therapy (Maraire grade I) at last follow-up (mean 3.9 years) and an additional 41.5 % had complete control of seizures with therapy (Maraire grade II).

CONCLUSIONS

Surgery is safe in the management of CMs in non-critical but also in critical supratentorial locations, with a caveat for deep structures such as the insula, the basal ganglia and the thalamus/hypothalamus.

The effect of different brain lesions on the reorganization of language functions within the dominant hemisphere assessed with task-based BOLD-fMRI

BACKGROUND AND PURPOSE

Language reorganization has been described in brain lesions with respect to their location and timing, but little is known with respect to their etiology. We used fMRI to investigate the effects of different types of left hemisphere lesions (GL = gliomas, TLE = temporal lobe epilepsy and CA = cavernous angioma) on the topographic intra-hemispheric language plasticity, also considering their location.

METHODS

Forty-seven right-handed patients with 3 different left hemisphere lesions (16 GL, 15 TLE and 16 CA) and 17 healthy controls underwent BOLD fMRI with a verb-generation task. Euclidean distance was used to measure activation peak shifts among groups with respect to reference Tailarach coordinates of Inferior Frontal Gyrus, Superior Temporal Sulcus and Temporo-Parietal Junction. Mixed-model ANOVAs were used to test for differences in activation peak shifts.

RESULTS

Significant activation peak shifts were found in GL patients with respect both to HC and other groups (TLA and CA). In addition, in the same group of patients a significant effect of tumor location (anterior or posterior) was detected.

CONCLUSIONS

We demonstrated that intra-hemispheric language plasticity is influenced by the type of lesion affecting the left hemisphere and that fMRI is especially valuable in the preoperative assessment of such reorganization in glioma patients.

Clinical characteristics and risk factors of cerebral cavernous malformation-related epilepsy

PURPOSE

This study aimed to summarize the clinical characteristics and explore the risk factors for cerebral cavernous malformation (CCM)-related epilepsy (CRE).

METHODS

We retrospectively analyzed the clinical data of patients with CCM in our cerebral vascular malformations database. Descriptive statistics were used to present the clinical characteristics of CRE patients. Patients were divided into a CRE and a non-CRE group according to clinical presentation. Binary logistic regression analysis was used to analyze the risk factors of CRE.

RESULTS

A total of 199 patients with CCM confirmed by postoperative pathological examination were enrolled, 93 of whom were diagnosed with CRE, and 34 patients had drug-resistant epilepsy. The most common seizure type of CRE patients was focal to bilateral tonic-clonic seizure (FBTCS), followed by focal impaired awareness motor seizure. All CCM lesions were supratentorial, 97.8% of which involved the cerebral cortex, 86.0% of lesions had hemosiderin rim, and 50.5% of lesions were located in the temporal lobe. Binary logistic regression analysis indicated that CCM diagnosis age ≤ 44 years (odds ratio [OR] 2.79, p = 0.010), temporal lobe lesion location (OR = 9.07, p = 0.042), medial temporal lobe lesion (OR = 14.09, p = 0.002), cortical involvement of the lesion (OR = 32.77, p = 0.010), and hemosiderin rim around the lesion (OR = 16.48, p = 0.001) significantly increased the risk of CRE.

CONCLUSIONS

The most common seizure type of CRE was FBTCS. Those whose CCM diagnosis age was ≤ 44 years, having a temporal lobe lesion location, especially the medial temporal lobe lesion, cortical involvement, and hemosiderin rim around the lesion had a higher risk of developing CRE.

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 Management of Seizures after Surgical Treatment of Supratentorial Cavernous Malformations : A Retrospective Single Centre Study

Objective

Seizure recurrence after the first-ever seizure in patients with a supratentorial cerebral cavernous malformation (CCM) is almost certain, so the diagnosis and treatment of epilepsy is justified. The optimal method of management of these patients is still a matter of debate. The aim of our study was to identify factors associated with postoperative seizure control and assess the surgical morbidity rate.

Methods

We retrospectively analysed 45 consecutive patients with a supratentorial CCM and symptomatic epilepsy in a single centre. Pre- and postoperative epidemiological data, seizure-related patient histories, neuroimaging results, surgery details and outcomes were obtained from hospital medical records. Seizure outcomes were assessed at least 12 months after surgery.

Results

Thirty-five patients (77.8%) were seizure free at the long-term follow-up (Engel class I); six (13,3%) had rare, nocturnal seizures (Engel class II); and four (8.9%) showed meaningful improvement (Engel class III). In 15 patients (33%) in the Engel I group; it was possible to discontinue antiepileptic medication. Although there was not statistical significance, our results suggest that patients can benefit from early surgery. No deaths occurred in our study, and mild postoperative neurologic deficits were observed in two patients (4%) at the long-term follow-up.

Conclusion

Surgical resection of CCMs should be considered in all patients with a supratentorial malformation and epilepsy due to the favourable surgical results in terms of the epileptic seizure control rate and low postoperative morbidity risk, despite the use of different predictors for the seizure outcome.

Epilepsy Syndromes: Current Classifications and Future Directions

This review describes the clinical presentations and treatment options for commonly recognized epilepsy syndromes in the pediatric age group, based on the 2017 International League Against Epilepsy classification. Structural epilepsies that are amenable to surgical intervention are discussed. Lastly, emerging technologies are reviewed that are expanding our knowledge of underlying epilepsy pathologies and will guide future syndromic classification systems including genetic testing and tissue repositories.

Seizure outcome in patients with cavernous malformation after early surgery

OBJECTIVE

To describe seizure outcome and complications in patients with cavernous malformations (CM) undergoing early versus late surgery.

METHODS

A database was created for all CM patients who presented with seizure referred to the neurosurgical clinic at an academic center. A telephone survey and chart review were conducted to evaluate for preoperative and postoperative seizure frequency. Postoperative seizure-free outcome of patients who had ≤2 preoperative seizures versus those that had >2 preoperative seizures was compared.

RESULTS

A total of 35 CM patients were included for analysis. Nineteen patients had ≤2 preoperative seizures and 16 patients had >2 preoperative seizures, six of them drug resistant for over two years. Among the ≤2 seizure group, 15 had only a single seizure before surgical resection. 94.7% of patients with ≤2 preoperative seizures and 62.5% of patients with >2 preoperative seizures were seizure free one year following surgical resection (p = 0.019). 78.9% of patients with ≤2 preoperative seizures and 25% of patients with >2 preoperative seizures were able to wean off AEDs (p < 0.001). Among those patients who had a single preoperative seizure, 100% of patients were seizure free at one year.

CONCLUSIONS

Early surgical resection for CM patients who present after a CM-related seizure is an effective, well tolerated treatment and has good chance to offer seizure freedom without the need for long-term antiepileptic medications. Outcome for patients operated with only one or two preoperative seizures may lead to better results than patients who delay the procedure.

Epileptogenic zone localization using intraoperative gamma oscillation regularity analysis in epilepsy surgery for cavernomas: patient series

BACKGROUND

In epilepsy surgery for cavernoma with intractable focal epilepsy, removal of the cavernoma with its surrounding hemosiderin deposition and other extended epileptogenic zone has been shown to improve postsurgical seizures. However, there has been no significant association between such an epileptogenic zone and intraoperative electrocorticography (ECoG) findings. The authors recently demonstrated that high regular gamma oscillation (30–70 Hz) regularity (GOR) significantly correlates with epileptogenicity.

OBSERVATIONS

The authors evaluated the utility of intraoperative GOR analysis in epilepsy surgery for cavernomas. The authors also analyzed intraoperative ECoG data from 6 patients with cavernomas. The GOR was calculated using a sample entropy algorithm. In 4 patients, the GOR was significantly high in the area with the pathological hemosiderin deposition. In 2 patients with temporal cavernoma, the GOR was significantly high in both the hippocampus and the area with the pathological hemosiderin deposition. ECoG showed no obvious epileptic waveforms in 3 patients, whereas extensive spikes were observed in 3 patients. All patients underwent cavernoma removal plus resection of the area with significantly high GOR. The 2 patients with temporal cavernomas underwent additional hippocampal transection. All patients were seizure free after surgery.

LESSONS

The high GOR may be a novel intraoperative marker of the epileptogenic zone in epilepsy surgery for cavernomas.

Treatment of Cerebral Cavernous Malformations Presenting With Seizures: A Systematic Review and Meta-Analysis

Background: Cerebral cavernous malformations (CCMs) presenting with seizures can be treated with neurosurgery or radiosurgery, but the ideal treatment remains unclear. Currently, there is no adequate randomized controlled trial comparing surgical treatment and radiotherapy for epileptogenic CCMs. Therefore, we conducted a systematic review and meta-analysis of available data from published literature to compare the efficacy and safety of neurosurgery and radiosurgery for epileptogenic CCMs. Methods: We performed a comprehensive search of the Ovid MEDLINE, Web of Science, PubMed, China Biological Medicine and China National Knowledge Infrastructure databases for studies published between January 1994 and October 2019. The search terms were as follows: "epilepsy," "seizures," "brain cavernous hemangioma," "cerebral cavernous malformation," "cerebral cavernous hemangioma," "hemangioma, cavernous, central nervous system." Two researchers independently extracted the data and reviewed all the articles. We compared the advantages and disadvantages of the two treatments. Results: A total of 45 studies were included in our analysis. Overall, the seizure control rate was 79% (95% CI: 75-83%) for neurosurgery and 49% (95% CI: 38-59%) for radiosurgery. In the neurosurgery studies, 4.4% of patients experienced permanent morbidity, while no patients in the radiotherapy studies had permanent morbidity. In addition, the results of subgroup analysis showed that ethnicity, CCMs location and average lesion number are likely significant factors influencing the seizure outcome following treatment. Conclusions: The epilepsy control rate after neurosurgery was higher than that after radiosurgery, but neurosurgery also had a relatively higher rate of permanent morbidity.

Beyond eloquence and onto centrality: a new paradigm in planning supratentorial neurosurgery

PURPOSE

Minimizing post-operational neurological deficits as a result of brain surgery has been one of the most pertinent endeavours of neurosurgical research. Studies have utilised fMRIs, EEGs and MEGs in order to delineate and establish eloquent areas, however, these methods have not been utilized by the wider neurosurgical community due to a lack of clinical endpoints. We sought to ascertain if there is a correlation between graph theory metrics and the neurosurgical notion of eloquent brain regions. We also wanted to establish which graph theory based nodal centrality measure performs the best in predicting eloquent areas.

METHODS

We obtained diffusion neuroimaging data from the Human Connectome Project (HCP) and applied a parcellation scheme to it. This enabled us to construct a weighted adjacency matrix which we then analysed. Our analysis looked at the correlation between PageRank centrality and eloquent areas. We then compared PageRank centrality to eigenvector centrality and degree centrality to see what the best measure of empirical neurosurgical eloquence was.

RESULTS

Areas that are considered neurosurgically eloquent tended to be predicted by high PageRank centrality. By using summary scores for the three nodal centrality measures we found that PageRank centrality best correlated to empirical neurosurgical eloquence.

CONCLUSION

The notion of eloquent areas is important to neurosurgery and graph theory provides a mathematical framework to predict these areas. PageRank centrality is able to consistently find areas that we consider eloquent. It is able to do so better than eigenvector and degree central measures.

Supratentorial Cavernous Malformations Involving the Corticospinal Tract and Sensory Motor Cortex: Treatment Strategies, Surgical Considerations, and Outcomes

BACKGROUND

Cavernous malformations (CMs) are congenital malformations and may be located anywhere in the brain. We present a series of CMs located close to or inside of the motor-sensory cortex or corticospinal tract (CST) with clinical onset due to hemorrhage or mass effect. In such cases, surgery becomes an acceptable option.

OBJECTIVE

To evaluate the role of diffusion tensor imaging (DTI), functional-magnetic-resonance imaging (fMRI), intraoperative neurophysiological monitoring, neuronavigation, and brain-mapping and the clinical results of surgical treatment of CMs in this critical location.

METHODS

The study included 54 patients harboring 22 cortical and 32 deep locations. This series was distinct because in group I, where the DTI was not obtained, and in the group II, where this evaluation was performed.

RESULTS

The postoperative permanent morbidity rate was 4% in the historical group for the deeper CMs, and there was no morbidity in the second group. DTI and fMRI permitted us to estimate the distance between the CMs and both the cortical activation cluster and the pyramidal tract. These data, in addition to intraoperative mapping and monitoring, made it necessary for us to perform a partial resection in 2 cases in the second series.

CONCLUSION

CMs are congenital lesions and CST fibers can run directly on their surface. Integration of fMRI and DTI data with intraoperative functional monitoring and direct cortical and subcortical mapping are mandatory to accomplish an optimal resection, tailoring the best surgical approach to the acceptable morbidity. A subtotal resection could be considered an option for deep locations.

Surgery for epilepsy

BACKGROUND

This is an updated version of the original Cochrane review, published in 2015.Focal epilepsies are caused by a malfunction of nerve cells localised in one part of one cerebral hemisphere. In studies, estimates of the number of individuals with focal epilepsy who do not become seizure-free despite optimal drug therapy vary between at least 20% and up to 70%. If the epileptogenic zone can be located, surgical resection offers the chance of a cure with a corresponding increase in quality of life.

OBJECTIVES

The primary objective is to assess the overall outcome of epilepsy surgery according to evidence from randomised controlled trials.Secondary objectives are to assess the overall outcome of epilepsy surgery according to non-randomised evidence, and to identify the factors that correlate with remission of seizures postoperatively.

SEARCH METHODS

For the latest update, we searched the following databases on 11 March 2019: Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid, 1946 to March 08, 2019), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

Eligible studies were randomised controlled trials (RCTs) that included at least 30 participants in a well-defined population (age, sex, seizure type/frequency, duration of epilepsy, aetiology, magnetic resonance imaging (MRI) diagnosis, surgical findings), with an MRI performed in at least 90% of cases and an expected duration of follow-up of at least one year, and reporting an outcome related to postoperative seizure control. Cohort studies or case series were included in the previous version of this review.

DATA COLLECTION AND ANALYSIS

Three groups of two review authors independently screened all references for eligibility, assessed study quality and risk of bias, and extracted data. Outcomes were proportions of participants achieving a good outcome according to the presence or absence of each prognostic factor of interest. We intended to combine data with risk ratios (RRs) and 95% confidence intervals (95% CIs).

MAIN RESULTS

We identified 182 studies with a total of 16,855 included participants investigating outcomes of surgery for epilepsy. Nine studies were RCTs (including two that randomised participants to surgery or medical treatment (99 participants included in the two trials received medical treatment)). Risk of bias in these RCTs was unclear or high. Most of the remaining 173 non-randomised studies followed a retrospective design. We assessed study quality using the Effective Public Health Practice Project (EPHPP) tool and determined that most studies provided moderate or weak evidence. For 29 studies reporting multivariate analyses, we used the Quality in Prognostic Studies (QUIPS) tool and determined that very few studies were at low risk of bias across domains.In terms of freedom from seizures, two RCTs found surgery (n = 97) to be superior to medical treatment (n = 99); four found no statistically significant differences between anterior temporal lobectomy (ATL) with or without corpus callosotomy (n = 60), between subtemporal or transsylvian approach to selective amygdalohippocampectomy (SAH) (n = 47); between ATL, SAH and parahippocampectomy (n = 43) or between 2.5 cm and 3.5 cm ATL resection (n = 207). One RCT found total hippocampectomy to be superior to partial hippocampectomy (n = 70) and one found ATL to be superior to stereotactic radiosurgery (n = 58); and another provided data to show that for Lennox-Gastaut syndrome, no significant differences in seizure outcomes were evident between those treated with resection of the epileptogenic zone and those treated with resection of the epileptogenic zone plus corpus callosotomy (n = 43). We judged evidence from the nine RCTs to be of moderate to very low quality due to lack of information reported about the randomised trial design and the restricted study populations.Of the 16,756 participants included in this review who underwent a surgical procedure, 10,696 (64%) achieved a good outcome from surgery; this ranged across studies from 13.5% to 92.5%. Overall, we found the quality of data in relation to recording of adverse events to be very poor.In total, 120 studies examined between one and eight prognostic factors in univariate analysis. We found the following prognostic factors to be associated with a better post-surgical seizure outcome: abnormal pre-operative MRI, no use of intracranial monitoring, complete surgical resection, presence of mesial temporal sclerosis, concordance of pre-operative MRI and electroencephalography, history of febrile seizures, absence of focal cortical dysplasia/malformation of cortical development, presence of tumour, right-sided resection, and presence of unilateral interictal spikes. We found no evidence that history of head injury, presence of encephalomalacia, presence of vascular malformation, and presence of postoperative discharges were prognostic factors of outcome.Twenty-nine studies reported multi-variable models of prognostic factors, and showed that the direction of association of factors with outcomes was generally the same as that found in univariate analyses.We observed variability in many of our analyses, likely due to small study sizes with unbalanced group sizes and variation in the definition of seizure outcome, the definition of prognostic factors, and the influence of the site of surgery AUTHORS' CONCLUSIONS: Study design issues and limited information presented in the included studies mean that our results provide limited evidence to aid patient selection for surgery and prediction of likely surgical outcomes. Future research should be of high quality, follow a prospective design, be appropriately powered, and focus on specific issues related to diagnostic tools, the site-specific surgical approach, and other issues such as extent of resection. Researchers should investigate prognostic factors related to the outcome of surgery via multi-variable statistical regression modelling, where variables are selected for modelling according to clinical relevance, and all numerical results of the prognostic models are fully reported. Journal editors should not accept papers for which study authors did not record adverse events from a medical intervention. Researchers have achieved improvements in cancer care over the past three to four decades by answering well-defined questions through the conduct of focused RCTs in a step-wise fashion. The same approach to surgery for epilepsy is required.

Predictors of Epileptic Seizures and Ability to Work in Supratentorial Cavernous Angioma Located Within Eloquent Brain Areas

BACKGROUND

The postoperative outcomes and the predictors of seizure control are poorly studied for supratentorial cavernous angiomas (CA) within or close to the eloquent brain area.

OBJECTIVE

To assess the predictors of preoperative seizure control, postoperative seizure control, and postoperative ability to work, and the safety of the surgery.

METHODS

Multicenter international retrospective cohort analysis of adult patients benefitting from a functional-based surgical resection with intraoperative functional brain mapping for a supratentorial CA within or close to eloquent brain areas.

RESULTS

A total of 109 patients (66.1% women; mean age 38.4 ± 12.5 yr), were studied. Age >38 yr (odds ratio [OR], 7.33; 95% confidence interval [CI], 1.53-35.19; P = .013) and time to surgery > 12 mo (OR, 18.21; 95% CI, 1.11-296.55; P = .042) are independent predictors of uncontrolled seizures at the time of surgery. Focal deficit (OR, 10.25; 95% CI, 3.16-33.28; P < .001) is an independent predictor of inability to work at the time of surgery. History of epileptic seizures at the time of surgery (OR, 7.61; 95% CI, 1.67-85.42; P = .003) and partial resection of the CA and/or of the hemosiderin rim (OR, 12.02; 95% CI, 3.01-48.13; P < .001) are independent predictors of uncontrolled seizures postoperatively. Inability to work at the time of surgery (OR, 19.54; 95% CI, 1.90-425.48; P = .050), Karnofsky Performance Status ≤ 70 (OR, 51.20; 95% CI, 1.20-2175.37; P = .039), uncontrolled seizures postoperatively (OR, 105.33; 95% CI, 4.32-2566.27; P = .004), and worsening of cognitive functions postoperatively (OR, 13.71; 95% CI, 1.06-176.66; P = .045) are independent predictors of inability to work postoperatively.

CONCLUSION

The functional-based resection using intraoperative functional brain mapping allows safe resection of CA and the peripheral hemosiderin rim located within or close to eloquent brain areas.

[Surgical treatment of epilepsy in patients with mediobasal temporal cavernous malformations]

OBJECTIVE

Epilepsy is a frequent clinical manifestation of cavernous malformations (CMs) of the mediobasal temporal region (MBTR). Surgical removal of CMs is an excellent technique for treating associated epilepsy and may range from pure lesionectomy to tailored resection of the temporal lobe.

PURPOSE

The study purpose was to determine the optimal surgical management for epilepsy in patients with CMs of the MBTR.

MATERIAL AND METHODS

We retrospectively analyzed the clinical data, neuroimaging findings, surgical techniques, and surgical outcomes in 11 patients with epilepsy and CMs of the MBTR. All patients underwent video-electroencephalography, magnetic resonance imaging, and computed tomography in the pre- and postoperative periods. Nine patients underwent preoperative implantation of foramen ovale electrodes. In all cases, surgery was accompanied by electrocorticography (ECoG).

RESULTS

CMs were located in the anterior MBTR in 7 cases, anterior and middle thirds of the MBTR in 1 case, middle third in 2 cases, and middle and posterior thirds in 1 case. In 8 patients, preoperative monitoring revealed a seizure onset area in the MBTR. These patients underwent cavernomectomy with ECoG-guided resection of the hemosiderin ring and adjacent tissue using the pterional (4 cases) or supracerebellar transtentorial approach (4). In 3 cases, anterior temporal lobectomy with cavernomectomy was additionally used due to spreading of pathological activity to the lateral temporal neocortex. Seizure control after surgery was excellent in 7 patients (class 1 ILAE) and good in 4 (class 2 ILAE).

CONCLUSION

Surgery in patients with epilepsy caused by CMs of the MBTR should be performed based on non-invasive and invasive presurgical evaluation. If the seizure onset area is located in the MBTR, lesionectomy with ECoG-guided resection of the adjacent temporal cortical areas can be performed using the pterional or supracerebellar transtentorial approach. Lateral spread of epileptic activity requires cavernomectomy and anterior temporal lobectomy.

Hippocampal Transection Plus Tumor Resection as a Novel Surgical Treatment for Temporal Lobe Epilepsy Associated with Cerebral Cavernous Malformations

OBJECTIVE

The optimal surgical treatment for cavernous malformation-related temporal lobe epilepsy (CRTLE) is still controversial because it frequently involves the hippocampus as an epileptogenic zone. Here we describe our unique surgical strategy of performing hippocampal transection (HT) plus tumor resection for CRTLE to solve the question of how to balance postoperative seizure outcomes and neuropsychologic outcomes.

METHODS

From 2005 to 2016, 7 cases of HT (3 on dominant side) plus tumor resection were performed for patients with CRTLE. We routinely perform intraoperative electrocorticography just before and after the resection of the tumor with hemosiderin rim. In cases with residual spikes from the hippocampus after the resection, we add HT, considering laterality of the lesion, preoperative memory functions, and magnetic resonance imaging abnormalities in hippocampi. Patient information, including seizure outcomes and preoperative and postoperative (24 months) Wechsler Memory Scale-Revised (WMS-R), were collected.

RESULTS

In the mean follow-up of 62.7 months (range 20-119), the postoperative seizure outcome was as follows: Engel class I in 6 cases (85.7%) and II in 1 case (14.3%). Perioperative changes in WMS-R score were as follows: 93.5 preoperatively versus 99.5 postoperatively (P = 0.408) in verbal memory and 90.7 versus 98.0 (P = 0.351) in delayed recall. Overall, no patient presented with more than 25% decline in any of the WMS-R indices postoperatively.

CONCLUSIONS

Despite the small sample size and noncontrolled study design, postoperative seizure outcomes were deemed acceptable with favorable memory outcomes, which rather improved postoperatively with marginal statistical significance. In patients with CRTLE, additional HT is a reasonable treatment option.

Gene Therapy with Tetracycline-Regulated Human Recombinant COLIA1 cDNA Direct Adenoviral Delivery Enhances Fracture Healing in Osteoporotic Rats

A number of previous studies have indicated that the genetic variation at the collage type I alpha 1 (COLIA1) gene locus influences susceptibility to osteoporosis. However, seldom have studies reported the effect of gene delivery using an adenovirus vector carrying human recombinant COLIA1 cDNA on stimulating osteogenic activity of osteoblasts and enhancing fracture healing of ovariectomized rats. The current study was performed to demonstrate whether direct gene delivery using an adenovirus vector carrying human recombinant COLIA1 cDNA could stimulate osteogenic activity of osteoblast in vitro and enhance fracture healing of ovariectomized rats in vivo. In vitro, the tet-on system regulated COLIA1 gene adenovirus was constructed and transfected to osteoblasts. COLIA1 mRNA and collagen type I levels were assessed by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay to determine whether adenovirus transfected successfully. Osteogenic activity of the osteoblasts was assessed by alkaline phosphatase activity, immunohistochemical staining, immunofluorescent staining, mineralized matrix formation, and extracellular calcium levels. In vivo, adenovirus-delivered COLIA1 gene was injected into the fracture site of the tibia in an ovariectomized rat model of osteoporosis, and bone callus condition was assessed to determine whether the COLIA1 gene could accelerate osteoporotic fracture healing. In vitro, the results showed that COLIA1 gene adenovirus transfection could increase osteoblast COLIA1 gene expression and collagen type I protein synthesis, increase alkaline phosphatase activity, and stimulate calcium nodules formation, which exhibited a direct osteogenic effect on the osteoblasts. In vivo, local injection of COLIA1 gene adenovirus increased collagen type I expression, restored bone mineral density, and accelerated fracture healing in ovariectomized rats, without increasing serum collagen type I and liver COLIA1 mRNA levels. This study suggests direct gene delivery using an adenovirus carrying human COLIA1 cDNA can stimulate the osteogenic activity of osteoblasts in vitro and enhance bone fracture healing in vivo. The tet-on system is an ideal gene regulatory system for effective and safe regulation of the therapeutic gene.

Gene Therapy for Bone Repair Using Human Cells: Superior Osteogenic Potential of Bone Morphogenetic Protein 2-Transduced Mesenchymal Stem Cells Derived from Adipose Tissue Compared to Bone Marrow

Ex vivo regional gene therapy strategies using animal mesenchymal stem cells genetically modified to overexpress osteoinductive growth factors have been successfully used in a variety of animal models to induce both heterotopic and orthotopic bone formation. However, in order to adapt regional gene therapy for clinical applications, it is essential to assess the osteogenic capacity of transduced human cells and choose the cell type that demonstrates the best clinical potential. Bone-marrow stem cells (BMSC) and adipose-derived stem cells (ASC) were selected in this study for in vitro evaluation, before and after transduction with a lentiviral two-step transcriptional amplification system (TSTA) overexpressing bone morphogenetic protein 2 (BMP-2; LV-TSTA-BMP-2) or green fluorescent protein (GFP; LV-TSTA-GFP). Cell growth, transduction efficiency, BMP-2 production, and osteogenic capacity were assessed. The study demonstrated that BMSC were characterized by a slower cell growth compared to ASC. Fluorescence-activated cell sorting analysis of GFP-transduced cells confirmed successful transduction with the vector and revealed an overall higher but not statistically significant transduction efficiency in ASC versus BMSC (90.2 ± 4.06% vs. 80.4 ± 8.51%, respectively; p = 0.146). Enzyme-linked immunosorbent assay confirmed abundant BMP-2 production by both cell types transduced with LV-TSTA-BMP-2, with BMP-2 production being significantly higher in ASC versus BMSC (239.5 ± 116.55 ng vs. 70.86 ± 24.7 ng; p = 0.001). Quantitative analysis of extracellular deposition of calcium (Alizarin red) and alkaline phosphatase activity showed that BMP-2-transduced cells had a higher osteogenic differentiation capacity compared to non-transduced cells. When comparing the two cell types, ASC/LV-TSTA-BMP-2 demonstrated a significantly higher mineralization potential compared to BMSC/LV-TSTA-BMP-2 7 days post transduction (p = 0.014). In conclusion, this study demonstrates that transduction with LV-TSTA-BMP-2 can significantly enhance the osteogenic potential of both human BMSC and ASC. BMP-2-treated ASC exhibited higher BMP-2 production and greater osteogenic differentiation capacity compared to BMP-2-treated BMSC. These results, along with the fact that liposuction is an easy procedure with lower donor-site morbidity compared to BM aspiration, indicate that adipose tissue might be a preferable source of MSCs to develop a regional gene therapy approach to treat difficult bone-repair scenarios.

Enhanced Bone Regeneration by Diabetic Cell-Based Adenoviral BMP-2 Gene Therapy in Diabetic Animals

The application of bone morphogenetic protein 2 (BMP-2) has been extensively investigated to improve diabetes-impaired bone healing; however, the delivery of BMP-2 by gene therapy for bone regeneration has rarely been investigated in diabetic animals. In this study, we aimed to evaluate which cells induce more new bone formation in diabetic animals when cell-based BMP2 gene therapy is applied. For this purpose, we harvested bone marrow stromal cells (BMSCs) twice in the same animal before (non-diabetic BMSCs; nBMSCs) and after diabetes induction (diabetic BMSCs; dBMSCs) using modified bone marrow ablation methods. And then, cells were transduced by adenoviral vectors carrying the BMP2 gene (AdBMP2). In in vitro, AdBMP2-transfected dBMSCs (B2/dBMSCs) produced higher BMP-2 mRNA levels over 48 h, whereas AdBMP2-transfected nBMSCs (B2/nBMSCs) exhibited a transient increase in BMP-2 mRNA followed by a decrease to the baseline level within 48 h. Both B2/dBMSCs and B2/nBMSCs induced secretion of BMP-2 for 3 weeks. However, B2/dBMSC BMP-2 secretion peaked from day 3 to 10, whereas B2/nBMSC BMP-2 secretion peaked from day 1 to 7. The analysis of osteogenic activity revealed that mineralization nodule formation and the expression levels of osteogenic genes were significantly higher in B2/dBMSCs than B2/nBMSCs and were accompanied by upregulation of canonical Wnt/β-catenin and Smad signaling. AdBMP2-transfected autologous cells were implanted into critical-sized calvarial defects in diabetic animals and induced significantly more bone regeneration than non-AdBMP2-transfected cells. In addition, B2/dBMSCs led to significantly more new bone formation than B2/nBMSCs. Thus, BMP2 gene therapy using diabetic cells effectively supported diabetic bone healing and it was related to the enhanced responses to AdBMP2 of dBMSCs.

Surgical Management and Long-Term Seizure Outcome After Surgery for Temporal Lobe Epilepsy Associated with Cerebral Cavernous Malformations

OBJECTIVE

Operative strategies for cerebral cavernous malformation (CCM)-associated temporal lobe epilepsy and timing of surgical intervention continue to be debated. This study aimed to establish an algorithm to evaluate the efficacy of surgical intervention strategies, to maximize positive surgical outcomes and minimize postsurgical neurologic deficits.

METHODS

47 patients having undergone operation for CCM-associated temporal lobe epilepsy were retrospectively reviewed. They had received a diagnostic series for seizure localization, including long-term video electroencephalography (vEEG), high-resolution magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT). In patients with mesial temporal lobe CCMs, the involved structures (amygdala, hippocampus, or parahippocampal gyrus) were resected in addition to the lesions. Patients with neocortical epileptogenic CCM underwent extended lesionectomy guided by intraoperative electrocorticography; further performance of amygdalohippocampectomy depended on the extent of hippocampal epileptogenicity.

RESULTS

The study cohort contained 28 patients with drug-resistant epilepsy (DRE), 12 with chronic epilepsy (CE), and 7 with sporadic seizure (SS). Normal temporal lobe metabolism was seen in 7/7 patients of the SS group. Hypometabolism was found in all patients with chronic disease except for those with posterior inferior and middle temporal gyrus cavernous malformations (CMs). Of the 31 patients with superficial neocortical CCM, 7 had normal PET without hippocampal sclerosis, 14 had ipsilateral temporal lobe hypometabolism without hippocampal sclerosis, and 10 had obvious hippocampal sclerosis and hypometabolism. Seizure freedom in DRE, CE, and SS was 82.1%, 75%, and 100%, respectively. A significant difference was found between lesion laterality and postoperative seizure control; the rate was lower in left-sided cases because of less aggressive resection.

CONCLUSIONS

Our study demonstrates that the data from the presurgical evaluation, particularly regarding CM location, responsiveness to antiepileptic drugs, and temporal lobe metabolism, are crucial parameters for choosing surgical approaches to CCM-associated temporal lobe epilepsy. By this operative strategy, patients may receive maximized seizure control and minimized postsurgical neurologic sequelae.

Early and late epilepsy surgery in focal epilepsies associated with long-term epilepsy-associated tumors

OBJECTIVE

Epilepsy surgery is an effective means of treating focal epilepsy associated with long-term epilepsy-associated tumors. This study evaluated a large population of surgically treated patients with childhood onset of epilepsy and a histologically confirmed diagnosis of long-term epilepsy-associated tumors. The authors analyzed long-term seizure outcomes to establish whether the time of surgery and patients' ages were determinant factors.

METHODS

The authors separately investigated several presurgical, surgical, and postsurgical variables in patients operated on before (pediatric group) and at or after (adult group) the age of 18 years. Patients with < 24 months of postsurgical follow-up were excluded from the analysis.

RESULTS

The patients who underwent surgery before 18 years of age showed better seizure outcomes than those after 18 years of age (80% vs 53.3% Engel Class Ia outcome, respectively; p < 0.001). Multivariate analysis showed that the only variables significantly associated with seizure freedom were complete resection of the lesion, a shorter duration of epilepsy, and temporal lobe resection.

CONCLUSIONS

The findings of this study indicate that pediatric patients are more responsive to epilepsy surgery and that a shorter duration of epilepsy, complete resection, and a temporal lobe localization are determinant factors for a positive seizure outcome.

Intraoperative high-field magnetic resonance imaging, multimodal neuronavigation, and intraoperative electrophysiological monitoring-guided surgery for treating supratentorial cavernomas

Objective

To determine the beneficial effects of intraoperative high-field magnetic resonance imaging (MRI), multimodal neuronavigation, and intraoperative electrophysiological monitoring-guided surgery for treating supratentorial cavernomas.

Methods

Twelve patients with 13 supratentorial cavernomas were prospectively enrolled and operated while using a 1.5 T intraoperative MRI, multimodal neuronavigation, and intraoperative electrophysiological monitoring. All cavernomas were deeply located in subcortical areas or involved critical areas. Intraoperative high-field MRIs were obtained for the intraoperative “visualization” of surrounding eloquent structures, “brain shift” corrections, and navigational plan updates.

Results

All cavernomas were successfully resected with guidance from intraoperative MRI, multimodal neuronavigation, and intraoperative electrophysiological monitoring. In 5 cases with supratentorial cavernomas, intraoperative “brain shift” severely deterred locating of the lesions; however, intraoperative MRI facilitated precise locating of these lesions. During long-term (>3 months) follow-up, some or all presenting signs and symptoms improved or resolved in 4 cases, but were unchanged in 7 patients.

Conclusions

Intraoperative high-field MRI, multimodal neuronavigation, and intraoperative electrophysiological monitoring are helpful in surgeries for the treatment of small deeply seated subcortical cavernomas.

Pathology of cavernous malformations

Cavernous malformations (CMs) are low-pressure angiographically occult lesions, composed of blood-filled sinusoidal locules known as "caverns." Although these lesions were once believed to be congenital in nature, there is compelling evidence to support de novo formation of CMs as well. They can occur as sporadic lesions or be inherited in an autosomal-dominant phenotype in familial forms of the disease. The pathophysiology of CMs is commonly believed to be due to abnormal vascular pathology. Three genes, CCM1, CCM2, and CCM3, have been extensively studied for their role in vascular pathology, resulting in abnormal angiogenesis and compromising the structural integrity of vessel endothelial cell. The expression of growth factors has been researched to gain insight into the dynamic behavior of CM lesions. Gross and microscopic images are utilized in this chapter to illustrate the pathologic findings of these lesions. Ultrastructural analysis demonstrates the aberrations in CM endothelial cells and structural integrity that may provide better understanding into how and why these lesions have a propensity to hemorrhage.

A predicted model for postoperative seizure outcomes after the surgical resection of supratentorial cavernous malformations

To explore a predicted model for postoperative seizure outcomes after the surgical resection of supratentorial cavernous malformations.This study was a retrospective review of consecutive patients with cerebral supratentorial cavernous malformations presenting with seizures. All patients underwent surgical resection of CCMs. Univariate and multivariate analyses were performed to determine the predictive value of the preoperative seizure frequency, seizure type, seizure duration, lesion location, lesion size, and the presence of residual hemosiderin.A total of 43 patients met the inclusion criteria. After a mean follow-up period of 40.95 months, 34 patients who were free from postoperative seizures were classified into Engel class I, and the remaining 9 patients were classified into Engel classes II-IV. A univariate analysis showed that the seizure frequency (χ = 13.440, P = 0.004) and seizure duration (χ = 5.145, P = 0.023) prior to surgery were associated with a worse postoperative seizure prognosis. Other covariates including age at onset, gender, a history of the medications taken, smoking status, family history, lesion characteristics, and the role of hemosiderin were not related to seizure outcomes. Logistic regression results demonstrated that the preoperative seizure frequency was an effective predictor (P = 0.004). The receiver operating characteristic curve indicated that area under the curve for the preoperative seizure frequency test was 0.833 (95% confidence interval 0.709-0.957, P = 0.002).The preoperative seizure frequency was a prognostic factor for postoperative seizure outcomes after surgical resection of supratentorial cavernous malformations. To obtain a favorable prognosis for CCM patients with preoperative seizures, early intervention might be a better choice.

Microsurgical treatment of patients with refractory epilepsy and mesial temporal cavernous malformations: Clinical experience of a tertiary epilepsy center

BACKGROUND

Mesiotemporal cavernous malformation can occur in 10-20% of patients with cerebral cavernomas and are frequently associated with refractory.

METHODS

A retrospective investigation was performed in the epilepsy clinic of a Brazilian tertiary referral epilepsy center, from January 2000 to March 2012.

RESULTS

A total of 21 patients were included in the study. Thirteen patients (62%) evolved to Engel I; 5 (24%) to Engel II, 2 (10%) to Engel III, and 1 (5%) to Engel IV. We observed that 10 (48%) patients with 12 years or less of epilepsy duration evolved to Engel I and 1 (5%) to Engel II; whereas from a total of 10 patients with epilepsy duration of more than 12 years, 3 (30%) evolved to Engel I and 7 (70%) to Engel II, III, or IV (P < 0.001 [bilateral]; P1 ≠ P2).

CONCLUSION

Postsurgical seizure outcome for temporal lobe epilepsy associated with mesiotemporal cavernomas is very satisfactory.

Temporal lobe epilepsy and cavernous malformations: surgical strategies and long-term outcomes

OBJECTIVE

Cerebral cavernous malformations (CCM) of the temporal lobe often present with seizures. Surgical resection of these lesions can offer durable seizure control. There is, however, no universally accepted methodology for assessing and surgically treating these patients. We propose an algorithm to maximize positive surgical outcomes (seizure control) while minimizing post-surgical neurological deficit.

METHODS

A retrospective review of 34 patients who underwent epilepsy surgery for radiographically proven temporal lobe CCM was conducted. Patients underwent a relatively standard work-up for seizure localization. In patients with mesial temporal lobe epilepsy (MTLE), a complete resection of the epileptogenic zone was performed including amygdalo-hippocampectomy in addition to a lesionectomy if not contraindicated by pre-operative work-up. Patients with neocortical epilepsy underwent intraoperative electrocorticography (ECoG)-guided lesionectomy.

RESULTS

Seizure-free rate for mesial and neocortical (anterior, lateral, and basal) location was 90 vs. 83 %, respectively. Complete resection of the lesion, irrespective of location, was statistically significant for seizure control (p = 0.018). There was no difference in seizure control based on disease duration or location (p > 0.05). Patients with mesial temporal CCM who presented with MTLE were presumed to also have mesial temporal sclerosis (MTS), or dual pathology. These patients underwent routine resection of the mesial structures. Interestingly, patients who had MTLE and basal (neocortical) lesions who underwent a mesial resection for suspected MTS were found not to have dual pathology.

CONCLUSIONS

Patients with temporal lobe CCM should be offered resection for durable seizure control, prevention of secondary epileptogenic foci, and elimination of hemorrhage risk. The preoperative work-up should follow a team approach. Surgical intervention should include complete lesionectomy in all cases. Intra or extra-operative ECoG for neocortical lesions may be beneficial. Management of mesial temporal CCMs (archicortex) should consider resection of a well-defined epileptogenic zone (including mesial structures) due to high probability of pathologically proven MTS. The use of this treatment algorithm is useful for the education and treatment of these patients.

The Role of Hemosiderin Excision in Seizure Outcome in Cerebral Cavernous Malformation Surgery: A Systematic Review and Meta-Analysis

Background and Purpose

Whether the excision of hemosiderin surrounding cerebral cavernous malformations (CCMs) is necessary to achieve a seizure-free result has been the subject of debate. Here, we report a systematic review of related literature up to Jan 1, 2015 including 594 patients to assess the effect of hemosiderin excision on seizure outcome in patients with CCMs by meta-analysis.

Methods

Ten studies comparing extended hemosiderin excision with only lesion resection were identified by searching the English-language literature. Meta-analyses, subgroup analyses and sensitivity analysis were conducted to determine the association between hemosiderin excision and seizure outcome after surgery.

Results

Seizure outcome was significantly improved in the patients who underwent an extended excision of the surrounding hemosiderin (OR, 0.62; 95% CI: 0.42–0.91; P = 0.01). In subgroup analysis, studies from Asia (OR, 0.42; 95% CI: 0.25–0.71; P = 0.001), male-majority (female ratio < 50%) studies (OR, 0.56; 95% CI: 0.33–0.96; P = 0.04), low occurrence rate of multiple CCMs (OR, 0.37; 95% CI: 0.20–0.71; P = 0.003), cohort studies (OR, 0.44; 95% CI: 0.28–0.68; P = 0.78), longer duration of seizure symptoms (> 1 year) before surgery (OR, 0.43; 95% CI: 0.22–0.84; P = 0.01), lesion diameter > 2 cm (OR, 0.41; 95% CI: 0.19–0.87; P = 0.02) and short-term (< 3 years) follow-up (OR, 0.48; 95% CI: 0.29–0.80; P = 0.005) tended to correlate with a significantly favorable outcome.

Conclusion

Patients who underwent extended surrounding hemosiderin excision could exhibit significantly improved seizure outcomes compared to patients without hemosiderin excision. However, further well-designed prospective multiple-center RCT studies are still needed.

Surgery for epilepsy

BACKGROUND

Focal epilepsies are caused by a malfunction of nerve cells localised in one part of one cerebral hemisphere. In studies, estimates of the number of individuals with focal epilepsy who do not become seizure-free despite optimal drug therapy vary according to the age of the participants and which focal epilepsies are included, but have been reported as at least 20% and in some studies up to 70%. If the epileptogenic zone can be located surgical resection offers the chance of a cure with a corresponding increase in quality of life.

OBJECTIVES

The primary objective is to assess the overall outcome of epilepsy surgery according to evidence from randomised controlled trials.The secondary objectives are to assess the overall outcome of epilepsy surgery according to non-randomised evidence and to identify the factors that correlate to remission of seizures postoperatively.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialised Register (June 2013), the Cochrane Central Register of Controlled Trials (CENTRAL 2013, Issue 6), MEDLINE (Ovid) (2001 to 4 July 2013), ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) for relevant trials up to 4 July 2013.

SELECTION CRITERIA

Eligible studies were randomised controlled trials (RCTs), cohort studies or case series, with either a prospective and/or retrospective design, including at least 30 participants, a well-defined population (age, sex, seizure type/frequency, duration of epilepsy, aetiology, magnetic resonance imaging (MRI) diagnosis, surgical findings), an MRI performed in at least 90% of cases and an expected duration of follow-up of at least one year, and reporting an outcome relating to postoperative seizure control.

DATA COLLECTION AND ANALYSIS

Three groups of two review authors independently screened all references for eligibility, assessed study quality and risk of bias, and extracted data. Outcomes were proportion of participants achieving a good outcome according to the presence or absence of each prognostic factor of interest. We intended to combine data with risk ratios (RR) and 95% confidence intervals.

MAIN RESULTS

We identified 177 studies (16,253 participants) investigating the outcome of surgery for epilepsy. Four studies were RCTs (including one that randomised participants to surgery or medical treatment). The risk of bias in the RCTs was unclear or high, limiting our confidence in the evidence that addressed the primary review objective. Most of the remaining 173 non-randomised studies had a retrospective design; they were of variable size, were conducted in a range of countries, recruited a wide demographic range of participants, used a wide range of surgical techniques and used different scales used to measure outcomes. We performed quality assessment using the Effective Public Health Practice Project (EPHPP) tool and determined that most studies provided moderate or weak evidence. For 29 studies reporting multivariate analyses we used the Quality in Prognostic Studies (QUIPS) tool and determined that very few studies were at low risk of bias across the domains.In terms of freedom from seizures, one RCT found surgery to be superior to medical treatment, two RCTs found no statistically significant difference between anterior temporal lobectomy (ATL) with or without corpus callosotomy or between 2.5 cm or 3.5 cm ATL resection, and one RCT found total hippocampectomy to be superior to partial hippocampectomy. We judged the evidence from the four RCTs to be of moderate to very low quality due to the lack of information reported about the randomised trial design and the restricted study populations.Of the 16,253 participants included in this review, 10,518 (65%) achieved a good outcome from surgery; this ranged across studies from 13.5% to 92.5%. Overall, we found the quality of data in relation to the recording of adverse events to be very poor.In total, 118 studies examined between one and eight prognostic factors in univariate analysis. We found the following prognostic factors to be associated with a better post-surgical seizure outcome: an abnormal pre-operative MRI, no use of intracranial monitoring, complete surgical resection, presence of mesial temporal sclerosis, concordance of pre-operative MRI and electroencephalography (EEG), history of febrile seizures, absence of focal cortical dysplasia/malformation of cortical development, presence of tumour, right-sided resection and presence of unilateral interictal spikes. We found no evidence that history of head injury, presence of encephalomalacia, presence of vascular malformation or presence of postoperative discharges were prognostic factors of outcome. We observed variability between studies for many of our analyses, likely due to the small study sizes with unbalanced group sizes, variation in the definition of seizure outcome, definition of the prognostic factor and the influence of the site of surgery, all of which we observed to be related to postoperative seizure outcome. Twenty-nine studies reported multivariable models of prognostic factors and the direction of association of factors with outcome was generally the same as found in the univariate analyses. However, due to the different multivariable analysis approaches and selective reporting of results, meaningful comparison of multivariate analysis with univariate meta-analysis is difficult.

AUTHORS' CONCLUSIONS

The study design issues and limited information presented in the included studies mean that our results provide limited evidence to aid patient selection for surgery and prediction of likely surgical outcome. Future research should be of high quality, have a prospective design, be appropriately powered and focus on specific issues related to diagnostic tools, the site-specific surgical approach and other issues such as the extent of resection. Prognostic factors related to the outcome of surgery should be investigated via multivariable statistical regression modelling, where variables are selected for modelling according to clinical relevance and all numerical results of the prognostic models are fully reported. Protocols should include pre- and postoperative measures of speech and language function, cognition and social functioning along with a mental state assessment. Journal editors should not accept papers where adverse events from a medical intervention are not recorded. Improvements in the development of cancer care over the past three to four decades have been achieved by answering well-defined questions through the conduct of focused RCTs in a step-wise fashion. The same approach to surgery for epilepsy is required.

Evaluation of Posterior Hippocampal Epileptogenicity During Epilepsy Surgery For Temporal Lobe Cavernoma by the Occipital Approach

BACKGROUND

Cavernomas frequently are associated with intractable epilepsy. When cavernomas located in the temporal lobe are associated with intractable epilepsy, the hippocampus also may have an epileptic focus. The objective in the present study was to clarify the importance of evaluation of the posterior hippocampal epileptogenicity during epilepsy surgery for posteromedial temporal lobe cavernoma.

CASE DESCRIPTIONS

In this study, we describe 2 rare cases of medically intractable epilepsy in patients with posteromedial temporal lobe cavernomas who underwent surgery via the occipital approach. Using longitudinal insertion of depth electrodes into the hippocampus, we evaluated epileptogenicity in both patients from the cavernoma cavity and its surrounding hemosiderin, as well as from the posterior hippocampus near the cavernoma. We show that the transoccipital approach to the posteromedial temporal lobe is compatible with depth electrode insertion and subdural electrode placement on the temporal lobe, enabling an accurate evaluation of potential epileptogenic zones in the posterior part of the hippocampus. Both patients did not experience any seizures and had no postoperative neurologic deficits, and their cognitive functions were intact.

CONCLUSIONS

The transoccipital approach enables the optimization of the extent of posterior hippocampectomy while avoiding unnecessary resection for seizure control. We suggest resecting the posterior part of the hippocampus in addition to the cavernoma and surrounding areas in patients with medically refractory epilepsy due to a posteromedial temporal cavernoma. Tailored systematic resection guided by intraoperative electrocorticography and electroencephalography with a depth electrode was important and necessary in the present cases.

Treatment and outcome of epileptogenic temporal cavernous malformations

Background:

The aim of this study is to explore the treatment and outcome of epileptogenic temporal lobe cavernous malformations (CMs).

Methods:

We analyzed retrospectively the profiles of 52 patients diagnosed as temporal lobe CMs associated with epilepsy. Among the 52 cases, 11 underwent a direct resection of CM along with the adjacent zone of hemosiderin rim without electrocorticogram (ECoG) monitoring while the other 41 cases had operations under the guidance of ECoG. Forty-six patients were treated by lesionectomy + hemosiderin rim while the other six were treated by lesionectomy + hemosiderin rim along with extended epileptogenic zone resection. The locations of lesions, the duration of illness, the manifestation, the excision ranges and the outcomes of postoperative follow-up were analyzed, respectively.

Results:

All of the 52 patients were treated by microsurgery. There was no neurological deficit through the long-term follow-up. Outcomes of seizure control are as follows: 42 patients (80.8%) belong to Engel Class I, 5 patients (9.6%) belong to Engel Class II, 3 patients (5.8%) belong to Engel Class III and 2 patients (3.8%) belong to Engel Class IV.

Conclusion:

Patients with epilepsy caused by temporal CMs should be treated as early as possible. Resection of the lesion and the surrounding hemosiderin zone is necessary. Moreover, an extended excision of epileptogenic cortex or cerebral lobes is needed to achieve a better prognosis if the ECoG indicates the existence of an extra epilepsy onset origin outside the lesion itself.

Gene therapy approaches to regenerating the musculoskeletal system

Injuries to the musculoskeletal system are common, debilitating and expensive. In many cases, healing is imperfect, which leads to chronic impairment. Gene transfer might improve repair and regeneration at sites of injury by enabling the local, sustained and potentially regulated expression of therapeutic gene products; such products include morphogens, growth factors and anti-inflammatory agents. Proteins produced endogenously as a result of gene transfer are nascent molecules that have undergone post-translational modification. In addition, gene transfer offers particular advantages for the delivery of products with an intracellular site of action, such as transcription factors and noncoding RNAs, and proteins that need to be inserted into a cell compartment, such as a membrane. Transgenes can be delivered by viral or nonviral vectors via in vivo or ex vivo protocols using progenitor or differentiated cells. The first gene transfer clinical trials for osteoarthritis and cartilage repair have already been completed. Various bone-healing protocols are at an advanced stage of development, including studies with large animals that could lead to human trials. Other applications in the repair and regeneration of skeletal muscle, intervertebral disc, meniscus, ligament and tendon are in preclinical development. In addition to scientific, medical and safety considerations, clinical translation is constrained by social, financial and logistical issues.

Beyond the lesion: the epileptogenic networks around cavernous angiomas

The relationship between epileptogenic lesions and the extension of epileptogenicity is a major challenge in presurgical evaluation of drug resistant epilepsies. In this study, we aimed at quantifying the epileptogenic properties of brain structures explored by depth electrodes in patients investigated by stereoelectroencephalography (SEEG) and suffering from focal drug-resistant epilepsy associated with cavernous angioma (CA). Epileptogenicity of the perilesional region and distant brain areas was calculated according to the "epileptogenicity index" (EI), a technique that allows mathematical quantification of rapid discharges at seizure onset taking into account the time at which the discharge occurs. Thirteen seizures from 6 patients were studied. Localization of the cavernoma was the frontal lobe (two cases), the temporal lobe (three cases) or the anterior insula (one case). Visual inspection of the ictal discharge showed that in the majority of cases (5/6) the perilesional region was either not involved or involved with other distant sites. Using EI quantification, complex patterns of epileptogenicity were observed in five patients. A large number of brain regions out of the lesional region disclosed higher values than the lesion site. Mean values in the perilesional region and in the extralesional sites were not significantly different (p=0.34). Complex organization of the epileptogenic zone may be found in drug-resistant CA associated epilepsy. Thus, this result should be borne in mind when patients with CA and drug resistant epilepsy are investigated. If there is a suspicion of a larger epileptogenic zone than the lesion, intra-cerebral exploration by SEEG may be required before surgery that may be guided by the definition of the EZ.

Rates and predictors of seizure freedom in resective epilepsy surgery: an update

Epilepsy is a debilitating neurological disorder affecting approximately 1 % of the world's population. Drug-resistant focal epilepsies are potentially surgically remediable. Although epilepsy surgery is dramatically underutilized among medically refractory patients, there is an expanding collection of evidence supporting its efficacy which may soon compel a paradigm shift. Of note is that a recent randomized controlled trial demonstrated that early resection leads to considerably better seizure outcomes than continued medical therapy in patients with pharmacoresistant temporal lobe epilepsy. In the present review, we provide a timely update of seizure freedom rates and predictors in resective epilepsy surgery, organized by the distinct pathological entities most commonly observed. Class I evidence, meta-analyses, and individual observational case series are considered, including the experiences of both our institution and others. Overall, resective epilepsy surgery leads to seizure freedom in approximately two thirds of patients with intractable temporal lobe epilepsy and about one half of individuals with focal neocortical epilepsy, although only the former observation is supported by class I evidence. Two common modifiable predictors of postoperative seizure freedom are early operative intervention and, in the case of a discrete lesion, gross total resection. Evidence-based practice guidelines recommend that epilepsy patients who continue to have seizures after trialing two or more medication regimens should be referred to a comprehensive epilepsy center for multidisciplinary evaluation, including surgical consideration.

Seizure outcome after surgical resection of supratentorial cavernous malformations plus hemosiderin rim in patients with short duration of epilepsy

OBJECTIVE

The objective of this study was to retrospectively review the postoperative seizure outcome in patients with short duration of epilepsy associated with cavernous malformations and analyze the effect of surgical methods on seizure outcome in such population.

METHODS

36 patients with short duration of epilepsy (shorter than 12 months) associated with cavernous malformations in temporal or frontal lobe underwent microsurgical resection. The patients were retrospectively divided into two groups: Group A (21 patients) with complete removal of hemosiderin rim and Group B (15 patients) with partial removal of hemosiderin rim. Clinical follow-up was achieved with telephone correspondence or outpatient assessment. The seizure outcome was based on Engel's classification.

RESULTS

After a mean follow-up period of 18 months, 77.8% of the patients (28/36) were classified into Engel class I, including 19 patients (90.5%) in the complete removal of hemosiderin rim group (Group A) and 9 patients (60%) in the partial removal of hemosiderin rim group (Group B). Seizure outcome was significantly better in Group A. There was no mortality and all the postoperative neurological deficits were recovered at the time of follow-up.

CONCLUSION

The analysis of the seizure outcome demonstrate patients with short duration of epilepsy associated with cavernous malformations could benefit greatly from complete resection of hemosiderin rim and cavernous malformations.

Surgical Resection Can Be Successful in a Large Fraction of Patients With Drug-Resistant Epilepsy Associated With Multiple Cerebral Cavernous Malformations

BACKGROUND:

Multiple cerebral cavernous malformations (mCCMs) are known as potentially epileptogenic lesions. Treatment might be multimodal. Management of patients with mCCMs and epilepsy is challenging.

OBJECTIVE:

To evaluate (1) algorhythmic therapeutic sequences in patients with epilepsy associated to mCCMs, (2) whether there are predictive parameters to anticipate the development of drug-resistant epilepsy, and (3) seizure after epilepsy surgery compared to conservatively-treated drug-resistant patients.

METHODS:

All inpatients and outpatients with epilepsy associated to mCCMs from 1990 to 2010 and follow-up &gt;12 months available were retrospectively analyzed.

RESULTS:

Twenty-three patients matched inclusion criteria. Epilepsy became drug-resistant in 18/23 (78%) patients. No predictors were found for development of drug-resistant epilepsy. Median follow-up for both groups was 7.8 years. Nine patients did not qualify for surgical therapy and were treated conservatively. One patient of this cohort (11%) was seizure-free (International League Against Epilepsy [ILAE] class 1). Surgical treatment was performed in 9 patients; 7/9 (78%) of these patients were seizure-free (ILAE class 1) after epilepsy surgery for at least 12 months compared with 1/9 patients in the non-operated group. In 7/9 cases (78%) the largest CCM was resected. In 8/9 (89%) not all CCMs were resected.

CONCLUSION:

After initial diagnosis of epilepsy associated to mCCMs, a primary conservative approach is reasonable. Surgical treatment can be successful in a large fraction of cases with drug-resistant epilepsy where an epileptogenic lesion is identified. Cases where surgery is not undertaken are likely to remain intractable.

Surgical management of epilepsy due to cerebral cavernomas using neuronavigation and intraoperative MR imaging

Objectives:

Cure from seizures due to cavernomas might be surgically achieved dependent on both, the complete removal of the cavernoma as well as its surrounding hemosiderin rim. High field intraoperative MRI imaging (iopMRI) and neuronavigation might play a crucial role to achieve both goals. We retrospectively investigated the long-term results and impact of intraoperative 1·5T MRI (iopMRI) and neuronavigation on the completeness of surgical removal of a cavernous malformation (CM) and its perilesional hemosiderin rim as well as reduction of surgical morbidity.

Methods:

26 patients (14 female, 12 male, mean age 39·1 years, range: 17–63 years) with CM related epilepsy were identified. Eighteen patients suffered from drug resistant epilepsy (69·2%). Mean duration of epilepsy was 11·9 years in subjects with drug resistant epilepsy (n  =  18) and 0·3 years in subjects presenting with first-time seizures (n  =  8). We performed 24 lesionectomies and two lesionectomies combined with extended temporal resections. Seven lesions were located extratemporally.

Results:

Complete CM removal was documented by postsurgical MRI in all patients. As direct consequence of iopMRI, refined surgery was necessary in 11·5% of patients to achieve complete cavernoma removal and in another 11·5% for complete resection of additional adjacent epileptogenic cortex. Removal of the hemosiderin rim was confirmed by iopMRI in 92% of patients. Two patients suffered from mild (7·7%) and one from moderate (3·8%) visual field deficits. Complete seizure control (Engel class 1A) was achieved in 80·8% of patients with a mean follow-up period of 47·7 months.

Discussion:

We report excellent long-term seizure control with minimal surgical morbidity after complete resection of CM using our multimodal approach.

Long-term seizure outcomes following resection of supratentorial cavernous malformations

OBJECTIVE

Symptomatic supratentorial cavernous malformations may present with seizure, headache, neurological deficit, or a combination thereof. Factors that contribute to treatment algorithms commonly include patient age, lesion size and location, lesion multiplicity, hemorrhage history, and the ability to control seizure activity with medication. A better appreciation of the impact of patient and lesion characteristics on post-operative seizure control may provide insight into management strategies. To determine long-term seizure outcomes following surgical resection of supratentorial cavernous malformations, the predictive value of characteristics including seizure duration and number, presence of generalized seizures, and lesion multiplicity and size on seizure control rate was evaluated.

METHODS

We performed a single institution retrospective review of consecutive patients with supratentorial cavernous malformations presenting with at least one seizure between 1995 and 2008. Univariate and multivariate analyses were used to determine the influence of patient and lesion characteristics on postoperative seizure control.

RESULTS

Fifty-six patients met inclusion criteria. Mean follow-up duration was 87.9 months. At last follow-up there were 46 patients (82.1%) that were free from impairing seizures (Engel Class 1). Ten patients (17.9%) were classified as Engel Class 2-4. Univariate analysis demonstrated that only the presence of multiple cavernomas was associated with worse post-operative seizure outcome (p=0.006). Multivariate analysis demonstrated that multiple cavernomas remained a significant predictor for development of worse seizure outcome controlling for number and duration of seizures prior to operation, presence of generalized tonic-clonic seizures, and size (odds ratio, 0.17; 95% confidence interval, 0.03, 0.99).

CONCLUSION

Resection of supratentorial cavernomas is associated with a high rate of postoperative seizure freedom. The presence of multiple cavernomas is predictive of seizure persistence following surgery.

Technical, Anatomical, and Functional Study after Removal of a Symptomatic Cavernous Angioma Located in Deep Wernicke's Territories with Cortico-Subcortical Awake Mapping

Introduction. The subcortical region underneath Wernicke's area (WA) is a critical crossing of the eloquent language pathways involved in all semantic, phonological, syntactic, and working memory elaboration. We report the resection of a CA located underneath the dominant WA discussing the functional and anatomical evidence provided by fMRI, dissections with Klingler's technique, and intraoperative mapping during awake surgery. Case Report. A 64-year-old right-handed female affected by daily complex focal seizures underwent f-MRI, showing language activations in the middle and inferior temporal gyri and an unusual free entry zone in the “classical” WA. The cortical intraoperative mapping partially confirmed the f-MRI results, and we approached the lesion directly through WA. Subcortical DES allowed the identification of the eloquent language pathways and the radical resection of the perilesional gliotic rim. The patient did not report deficits and she is seizures and drug free after 1-year surgery. Discussion. Cortical DES demonstrated the variability of the eloquent areas within the cortex of the dominant temporal lobe. The subcortical DES confirmed the crucial role in language elaboration and the anatomical course of the bundles underneath WA. Conclusions. Awake surgery with DES represents a reliable and dynamic technique also for safer and functional-customized resection of CAs.

The outlook for adults with epileptic seizure(s) associated with cerebral cavernous malformations or arteriovenous malformations

Cerebral cavernous malformations (CCMs) and arteriovenous malformations (AVMs) are common: their asymptomatic prevalence on brain magnetic resonance imaging (MRI) is 1 in 625 and 1 in 2,000, respectively. The risk of epileptic seizure(s) for people with AVMs and CCMs affects their domestic, social, and professional lives, and may influence their decisions about treatment. This article summarizes the seizure risks for people with AVMs and CCMs, gleaned from published original articles indexed in OVID Medline and Embase before 1 January 2012. In the absence of prior intracranial hemorrhage and nonhemorrhagic focal neurologic deficit, a population-based study in Scotland, United Kingdom, found that the 5-year risks of first seizure were 8% for AVM and 4% for CCM; presentation with intracranial hemorrhage or focal neurologic deficit raised this risk for AVM (23%) but not for CCM (6%). Features associated with the occurrence of epileptic seizures for CCM are lesion multiplicity and cortical CCM location, whereas for AVM the most consistently reported associations are younger age, temporal location, cortical involvement, and nidus diameter >3 cm. In the absence of prior intracranial hemorrhage and nonhemorrhagic focal neurologic deficit, the 5-year risk of developing epilepsy following a first seizure is 58% for AVM and 94% for CCM, though there is no difference in the chance of achieving 2-year seizure freedom in this time frame (45% AVM vs. 47% CCM). Observational case series describe encouraging differences in seizure frequency before and after AVM and CCM treatment, but the shortage of studies demonstrating dramatic effects in comparison to concurrent control groups justifies the need for more controlled studies, ideally with randomized treatment allocation when the benefits of AVM or CCM treatment are uncertain.

The pig as an experimental model for clinical craniofacial research

The pig represents a useful, large experimental model for biomedical research. Recently, it has been used in different areas of biomedical research. The aim of this study was to review the basic anatomical structures of the head region in the pig in relation to their use in current research. Attention was focused on the areas that are frequently affected by pathological processes in humans: the oral cavity with teeth, salivary gland, orbit, nasal cavity and paranasal sinuses, maxilla, mandible and temporomandibular joint. Not all of the structures have an equal morphology in the pig and human, and these morphological dissimilarities must be taken into account before choosing the pig as an experimental model for regenerative medicine.

Ex vivo bone morphogenetic protein-2 gene delivery using bone marrow stem cells in rabbit maxillary sinus augmentation in conjunction with implant placement

BACKGROUND

This study evaluates the potential of bone morphogenetic protein 2 (BMP-2) gene-transduced bone marrow stem cells (BMSCs) to facilitate osseous healing after rabbit maxillary sinus augmentation in conjunction with implant placement.

METHODS

Autologous BMSCs derived from New Zealand white rabbits were cultured and transduced with BMP-2 using an adenovirus vector. Transduced BMSCs (BMP-2/BMSCs) were then combined with a deproteinized bovine bone mineral (DBBM) scaffold. Twenty-seven animals were randomly allocated into three groups: 1) control, sinus grafted with DBBM alone; 2) BMSC, sinus grafted with non-transduced BMSCs and DBBM; and 3) BMP-2/BMSC, sinus grafted with BMP-2/BMSCs and DBBM. During these procedures, a mini-implant was placed in the floor of the sinus. Animals were sacrificed at 2, 4, and 8 weeks after surgery. New bone area and bone-to-implant contact (BIC) were evaluated histomorphometrically.

RESULTS

At 2 and 4 weeks, the BMP-2/BMSC group showed more new bone area and higher BIC than the other two groups. BMP-2/BMSCs were detected with confocal microscopy for up to 4 weeks, which indicates that transduced cells contributed to new bone formation. However, at 8 weeks, there was no difference in new bone area or BIC among the three groups.

CONCLUSIONS

These results suggest that BMP-2 delivery using BMSCs may result in earlier and increased bone formation in the maxillary sinus. This finding may offer more stable bone support to implants and reduce healing times. However, this study also revealed limitations in the stimulatory effect of BMP-2/BMSCs, such as diminished activity over time in later healing stages.

Surgical treatment of symptomatic cerebral cavernous malformations in eloquent brain regions

BACKGROUND

Despite the increased risk of hemorrhage and deteriorating neurological function of once-bled cerebral cavernous malformations (CM), the management of eloquently located CMs remains controversial.

METHODS

All eloquently located CMs (n = 45) surgically treated between 03/2006 and 04/2011 in our department were consecutively evaluated. Eloquence was characterized according to Spetzler and Martin's definition. The following locations were approached: brainstem, n = 16; sensorimotor, n = 8; visual pathway, n = 7; cerebellum (deep nuclei and peduncles), n = 7; basal ganglia, n = 4, and language, n = 3. Follow-up data was available for 41 patients (91 %) with a median interval of 14 months. Outcomes were evaluated according to the Glasgow outcome and the modified Rankin scale.

RESULTS

Immediately after surgery, 47 % (n = 21) had a new deficit. At follow-up, 80 % (n = 36) recovered to at least preoperative status or were better than before surgery, 9 % (n = 4) exhibited a slight, and 7 % (n = 3) had a moderate neurological impairment. Only two cases (4 %) with a new permanent severe deficit were observed, both related to dorsal brainstem surgery. The outcome after the surgery of otherwise located brainstem CMs was as beneficial as that for non-brainstem CMs. Patients with initially poor neurological performance fared worse than oligosymptomatic patients.

CONCLUSIONS

Despite the high postoperative transient morbidity, the majority improved profoundly during follow-ups. Compared with natural history, surgical treatment should be considered for all eloquent symptomatic CMs. Dorsal brainstem location and poor preoperative neurological status are associated with an increased postoperative morbidity.