MRI and pathology comparisons in Rasmussen's encephalitis: a multi-institutional examination of hemispherotomy outcomes relative to imaging and histological severity.

PURPOSE: Rasmussen encephalitis (RE) is a very rare chronic neurological disorder of unilateral inflammation of the cerebral cortex. Hemispherotomy provides the best chance at achieving seizure freedom in RE patients, but with significant risks and variable long-term outcomes. The goal of this study is to utilize our multicenter pediatric cohort to characterize if differences in pathology and/or imaging characterization of RE may provide a window into post-operative seizure outcomes, which in turn could guide decision-making for parents and healthcare providers. METHODS: This multi-institutional retrospective review of medical record, imaging, and pathology samples was approved by each individual institution's review board. Data was collected from all known pediatric cases of peri-insular functional hemispherotomy from the earliest available electronic medical records. Mean follow-up time was 4.9 years. Clinical outcomes were measured by last follow-up visit using both Engel and ILAE scoring systems. Relationships between categorical and continuous variables were analyzed with Pearson correlation values. RESULTS: Twenty-seven patients met study criteria. No statistically significant correlations existed between patient imaging and pathology data. Pathology stage, MRI brain imaging stages, and a combined assessment of pathology and imaging stages showed no statistically significant correlation to post-operative seizure freedom rates. Hemispherectomy Outcome Prediction Scale scoring demonstrated seizure freedom in only 71% of patients receiving a score of 1 and 36% of patients receiving a score of 2 which were substantially lower than predicted. CONCLUSIONS: Our analysis did not find evidence for either independent or combined analysis of imaging and pathology staging being predictive for post peri-insular hemispherotomy seizure outcomes, prompting the need for other biomarkers to be explored. Our data stands in contrast to the recently proposed Hemispherectomy Outcome Prediction Scale and does not externally validate this metric for an RE cohort.

Comparing electrical stimulation functional mapping with subdural electrodes and stereoelectroencephalography.

OBJECTIVE: Electrical stimulation mapping (ESM) is the clinical standard for functional localization with subdural electrodes (SDE). As stereoelectroencephalography (SEEG) has emerged as an alternative option, we compared functional responses, afterdischarges (ADs), and unwanted ESM-induced seizures (EISs) between the two electrode types. METHODS: Incidence and current thresholds for functional responses (sensory, motor, speech/language), ADs, and EISs were compared between SDE and SEEG using mixed models incorporating relevant covariates. RESULTS: We identified 67 SEEG ESM and 106 SDE ESM patients (7207 and 4980 stimulated contacts, respectively). We found similar incidence of language and motor responses between electrode types; however, more SEEG patients reported sensory responses. ADs and EISs occurred less commonly with SEEG than SDE. Current thresholds for language, face motor, and upper extremity (UE) motor responses and EIS significantly decreased with age. However, they were not affected by electrode type, premedication, or dominant hemispheric stimulation. AD thresholds were higher with SEEG than with SDE. For SEEG ESM, language thresholds remained below AD thresholds up to 26 years of age, whereas this relationship was inverse for SDE. Also, face and UE motor thresholds fell below AD thresholds at earlier ages for SEEG than SDE. AD and EIS thresholds were not affected by premedication. SIGNIFICANCE: SEEG and SDE have clinically relevant differences for functional brain mapping with electrical stimulation. Although evaluation of language and motor regions is comparable between SEEG and SDE, SEEG offers a higher likelihood of identifying sensory areas. A lower incidence of ADs and EISs, and a favorable relationship between functional and AD thresholds suggest superior safety and neurophysiologic validity for SEEG ESM than SDE ESM.

Neuropsychological outcomes after epilepsy surgery: A comparison of stereo electroencephalography and subdural electrodes.

BACKGROUND AND PURPOSE: We analyzed the association of neuropsychological outcomes after epilepsy surgery with the intracranial electrode type (stereo electroencephalography [SEEG] and subdural electrodes [SDE]), and electrical stimulation mapping (ESM) of speech/language. METHODS: Drug-resistant epilepsy patients who underwent comprehensive neuropsychological evaluation before and 1 year after epilepsy surgery were included. SEEG and SDE subgroups were matched by age, handedness, operated hemisphere, and seizure freedom. Postsurgical neuropsychological outcomes (adjusted for presurgical scores) and reliable change indices were analyzed as functions of electrode type and ESM. RESULTS: Ninety-nine patients aged 6-29 years were included with similar surgical resection/ablation volumes in the SEEG and SDE subgroups. Most of the neuropsychological outcomes were comparable between SEEG and SDE subgroups; however, Working Memory and Processing Speed were significantly improved in the SEEG subgroup. Undergoing language ESM was associated with significant improvements in Spelling, Letter-Word Identification, Vocabulary, Verbal Comprehension, Verbal Learning, and Story Memory scores, but a decline in Calculation scores. CONCLUSIONS: Intracranial evaluations with SEEG and SDE are comparable in terms of long-term postsurgical neuropsychological outcomes. Our data suggest that SEEG may be associated with improvements in working memory and processing speed, representing cognitive domains served by spatially distributed networks. Our study also supports wider use of language ESM before epilepsy surgery, preferably using other language tasks in addition to visual naming. Rather than the type of electrode, postsurgical neuropsychological outcomes are driven by whether language ESM was performed or not, with beneficial effects of language mapping.

Spatial and Temporal Comparisons of Calcium Channel and Intrinsic Signal Imaging During in Vivo Cortical Spreading Depolarizations in Healthy and Hypoxic Brains.

BACKGROUND: Spreading depolarizations (SDs) can be viewed at a cellular level using calcium imaging (CI), but this approach is limited to laboratory applications and animal experiments. Optical intrinsic signal imaging (OISI), on the other hand, is amenable to clinical use and allows viewing of large cortical areas without contrast agents. A better understanding of the behavior of OISI-observed SDs under different brain conditions is needed. METHODS: We performed simultaneous calcium and OISI of SDs in GCaMP6f mice. SDs propagate through the cortex as a pathological wave and trigger a neurovascular response that can be imaged with both techniques. We imaged both mechanically stimulated SDs (sSDs) in healthy brains and terminal SDs (tSDs) induced by system hypoxia and cardiopulmonary failure. RESULTS: We observed a lag in the detection of SDs in the OISI channels compared with CI. sSDs had a faster velocity than tSDs, and tSDs had a greater initial velocity for the first 400 µm when observed with CI compared with OISI. However, both imaging methods revealed similar characteristics, including a decrease in the sSD (but not tSD) velocities as the wave moved away from the site of initial detection. CI and OISI also showed similar spatial propagation of the SD throughout the image field. Importantly, only OISI allowed regional ischemia to be detected before tSDs occurred. CONCLUSIONS: Altogether, data indicate that monitoring either neural activity or intrinsic signals with high-resolution optical imaging can be useful to assess SDs, but OISI may be a clinically applicable way to predict, and therefore possibly mitigate, hypoxic-ischemic tSDs.

Craniosynostosis is a feature of Costello syndrome.

Costello syndrome (CS) is an autosomal dominant disorder caused by pathogenic variants in HRAS. Craniosynostosis is a known feature of other RASopathies (Noonan and cardiofaciocutaneous syndromes) but not CS. We describe four individuals with CS and craniosynostosis and present a summary of all previously reported individuals with craniosynostosis and RASopathy.

Comparison of outcomes after stereoelectroencephalography and subdural grid monitoring in pediatric tuberous sclerosis complex.

OBJECTIVE: Patients with tuberous sclerosis complex (TSC) epilepsy present with unique clinical challenges such as early seizure onset and high rates of intractability and multifocality. Although there are numerous studies about the safety and efficacy of stereoelectroencephalography (SEEG), this topic has not been studied in TSC patients who have distinct epilepsy profiles. The authors investigated subdural grid (SDG) and SEEG monitoring to determine whether these procedures lead to similar seizure and safety outcomes and to identify features unique to this pediatric population. METHODS: TSC patients who underwent SDG or SEEG placement and a second epilepsy surgery during the period from 2007 to 2021 were included in this single-center retrospective cohort analysis. Various patient, hospitalization, and epilepsy characteristics were collected. RESULTS: A total of 50 TSC patients were included in this study: 30 were included in the SDG cohort and 20 in the SEEG cohort. Baseline weekly seizure count did not significantly differ between the 2 groups (p = 0.412). The SEEG group had a greater mean baseline number of antiepileptic drugs (AEDs) (3.0 vs 2.0, p = 0.003), higher rate of previous surgical interventions (25% vs 0%, p = 0.007), and larger proportion of patients who underwent bilateral monitoring (50% vs 13.3%, p = 0.005). Despite this, there was no significant difference in seizure freedom between the SDG and SEEG cohorts. The mean reduction in seizure count was 84.9% and 47.8% of patients were seizure free at last follow-up (mean 79.4 months). SEEG trended toward being a safer procedure than SDG monitoring, with a shorter mean ICU stay (0.7 days vs 3.9 days, p < 0.001), lower blood transfusion rate (0% vs 13.3%, p = 0.140), and lower surgical complication rate (0% vs 10%, p = 0.265). CONCLUSIONS: In the comparison of the SDG and SEEG cohorts, the SEEG group included patients who appeared to receive more aggressive management and have a higher rate of multifocality, more prior surgical interventions, more AEDs at baseline, and a higher rate of bilateral invasive monitoring. Despite this, the SEEG cohort had similar seizure outcomes and a trend toward increased safety. Based on these findings, SEEG appears to allow for monitoring of a wider breadth of TSC patients given its minimally invasive nature and its relative simplicity for monitoring numerous regions of the brain.

Partial suturectomy for phenotypical craniosynostosis caused by incomplete fusion of cranial sutures: a novel surgical solution.

OBJECTIVE: Patients presenting with head shape changes phenotypical for craniosynostosis may have incomplete fusion of the involved sutures. The surgical literature is lacking in appropriate management strategies for these patients. In this paper, the authors evaluate their experience with a novel treatment strategy: suturectomy of only the fused portion followed by helmeting therapy in patients with skull deformity secondary to incomplete suture synostosis. METHODS: Patients with craniosynostosis with incomplete suture fusion requiring operative intervention between 2018 and 2020 were included for evaluation. Patients were selected for partial suturectomy if the patent portion of the suture had a normal appearance. All patients underwent craniectomy of the involved portion of the synostosed suture. Intraoperative ultrasound was used to reassess the degree of fusion at the time of surgery and incision planning. A 2- to 3-cm strip craniectomy was performed under direct visualization through a single minimal access incision. Postoperative helmeting was utilized for all patients. Demographic and perioperative data were collected, including laser scan data in the form of cranial index (CI) and cranial vault asymmetry (CVA), defined as the difference between two diagonal measurements, from the frontozygomaticus to the opposite eurion. RESULTS: Four males and 1 female with a mean age of 2.8 months (range 1.1-3.9 months) at presentation were included. All patients had incomplete sagittal synostosis (one patient also had an incomplete left lambdoid synostosis and another had an incomplete left coronal synostosis). The mean age at surgery was 3.5 months (range 2.0-4.7 months) without any major complications. All patients were compliant with postoperative helmeting. The average age at the last follow-up was 12.8 months (range 5.3-23.7 months) with a mean follow-up duration of 9.3 months (range 0.5-19.6 months). Final laser scan evaluations were available for 3 patients and showed an improvement of the CI from an average of 71.3 (range 70-73) to 84.3 (range 82-86). The CVA improved from an average of 9.67 mm (range 2-22 mm) to 1.67 mm (range 1-2 mm). CONCLUSIONS: Minimally invasive direct excision of the involved portion of fused cranial sutures followed by helmet therapy for phenotypical craniosynostosis is a safe and effective treatment strategy. This technique is suitable for very young patients and appears to offer similar outcomes to complete suturectomy. Further studies are required to see if this approach reduces the deformity severity for patients requiring vault remodeling later in life.

Functional Neuroanatomy of Secondary Self-Injurious Behavior.

BACKGROUND: Secondary self-injurious behavior (SSIB) is underreported and predominantly not associated with suicide. In both adults and children, SSIB can cause intractable self-harm and is associated with a variety of clinical disorders, particularly those involving dysfunctional motor control. METHODS: We performed a literature review evaluating the clinical efficacy of deep-brain stimulation (DBS) as modulating SSIB observations and review current progress in preclinical SSIB animal studies. RESULTS: Neuromodulation is an effective therapeutic option for several movement disorders. Interestingly, this approach is emerging as a potentially effective treatment for movement disorder-associated SSIB (secondary); however, it is important to understand the neuroanatomy, clinical appraisal, and outcome data when considering surgical therapy for SSIB. CONCLUSION: The current review examines the literature encompassing animal models and human case studies while identifying existing hypotheses from cytoarchitectonic-based targeting to neurotransmitter-based pathways. This review also highlights the need for awareness of an underrecognized pathology that may be amenable to DBS.

Subdural grid and depth electrode monitoring in pediatric patients.

Invasive electroencephalographic monitoring with implantable subdural electrodes and intraparenchymal depth electrodes has become a basic tenet of epilepsy surgery. Improved localization of epileptic foci justifies the secondary procedure and monitoring period in many patients. Informed use of invasive monitoring in conjunction with imaging and functional studies makes epilepsy surgery a smaller, safer, and more effective endeavor. Herein we review the history, indications, implementation, and foreseeable future of grid, strip, and depth electrode use.

Predicting symptomatic cerebral vasospasm after aneurysmal subarachnoid hemorrhage with an artificial neural network in a pediatric population.

PURPOSE: Artificial neural networks (ANN) are increasingly applied to complex medical problem solving algorithms because their outcome prediction performance is superior to existing multiple regression models. ANN can successfully identify symptomatic cerebral vasospasm (SCV) in adults presenting after aneurysmal subarachnoid hemorrhage (aSAH). Although SCV is unusual in children with aSAH, the clinical consequences are severe. Consequently, reliable tools to predict patients at greatest risk for SCV may have significant value. We applied ANN modeling to a consecutive cohort of pediatric aSAH cases to assess its ability to predict SCV. METHODS: A retrospective chart review was conducted to identify patients < 21 years of age who presented with spontaneously ruptured, non-traumatic, non-mycotic, non-flow-related intracranial arterial aneurysms to our institution between January 2002 and January 2015. Demographics, clinical, radiographic, and outcome data were analyzed using an adapted ANN model using learned value nodes from the adult aneurysmal SAH dataset previously reported. The strength of the ANN prediction was measured between - 1 and 1 with - 1 representing no likelihood of SCV and 1 representing high likelihood of SCV. RESULTS: Sixteen patients met study inclusion criteria. The median age for aSAH patients was 15 years. Ten underwent surgical clipping and 6 underwent endovascular coiling for definitive treatment. One patient experienced SCV and 15 did not. The ANN applied here was able to accurately predict all 16 outcomes. The mean strength of prediction for those who did not exhibit SCV was - 0.86. The strength for the one patient who did exhibit SCV was 0.93. CONCLUSIONS: Adult-derived aneurysmal SAH value nodes can be applied to a simple AAN model to accurately predict SCV in children presenting with aSAH. Further work is needed to determine if ANN models can prospectively predict SCV in the pediatric aSAH population in toto; adapted to include mycotic, traumatic, and flow-related origins as well.

Cortical gene expression: prognostic value for seizure outcome following temporal lobectomy and amygdalohippocampectomy.

Whole genome analyses were performed to test the hypothesis that temporal cortical gene expression differs between epilepsy patients rendered seizure-free versus non-seizure-free following anterior temporal lobectomy with amygdalohippocampectomy (ATL/AH). Twenty four patients underwent ATL/AH to treat medically intractable seizures of temporal lobe origin (mean age 35.5 years, mean follow-up 42.2 months); they were then dichotomized into seizure-free and non-seizure-free groups. Tissue RNA was isolated from the lateral temporal cortex and gene expression analysis was performed. Whole genome data were analyzed for prognostic value for seizure-free outcome following ATL/AH by logistic regression. Genes that could distinguish seizure outcome groups were identified based on providing an accuracy of >0.90 judging by area under the receiver operating characteristic curve, AUC, with a P value of the slope coefficient of <0.05. Four genes and seven RNA probes were with prognostic value for post-operative seizure-free outcome. Gene expression associated with seizure-free outcome included relative down-regulation of zinc finger protein 852 (ZNF852), CUB domain-containing protein 2 (CDCP2), proline-rich transmembrane protein 1 (PRRT1), hypothetical LOC440200 (FLJ41170), RNA probe 8047763, RNA probe 8126238, RNA probe 8113489, RNA probe 8092883, RNA probe 7935228, RNA probe 806293, and RNA probe 8104131. This study describes the predictive value of temporal cortical gene expression for seizure-free outcome after ATL/AH. Four genes and seven RNA probes were found to predict post-operative seizure-free outcome. Future prospective investigation of these genes and probes in human brain tissue and blood could establish new biomarkers predictive of seizure outcome following ATL/AH.

Residual neurological function after sacral root resection during en-bloc sacrectomy: a systematic review.

PURPOSE: Sacrectomy is a highly demanding surgery representing the main treatment for primary tumors arising in the sacrum and pelvis. Unfortunately, it is correlated with loss of important function depending on the resection level and nerve roots sacrificed. The current literature regarding residual function after sacral resection comes from several small case series. The goal of this review is to appraise residual motor function and gait, sensitivity, bladder, bowel, and sexual function after sacrectomies, with consideration to the specific roots sacrificed. METHODS: An exhaustive literature search was conducted. All manuscripts published before May 2015 regarding residual function after sacrectomy were considered; if a clear correlation between root level and functioning was not present, the paper was excluded. The review identified 15 retrospective case series, totaling 244 patients; 42 patients underwent sacrectomies sparing L4/L4, L4/L5 and L5/L5; 45 sparing both L5 and one or both S1 roots; 8 sparing both S1 and one S2; 48 sparing both S2; 11 sparing both S2 and one S3, 54 sparing both S3, 9 sparing both S3 and one or both S4, and 27 underwent unilateral variable resection. RESULTS: Patients who underwent a sacrectomy maintained functionally normal ambulation in 56.2 % of cases when both S2 roots were spared, 94.1 % when both S3 were spared, and in 100 % of more distal resections. Normal bladder and bowel function were not present when both S2 were cut. When one S2 root was spared, normal bladder function was present in 25 % of cases; when both S2 were spared, 39.9 %; when one S3 was spared, 72.7 %; and when both S3 were spared, 83.3 %. Abnormal bowel function was present in 12.5 % of cases when both S1 and one S2 were spared; in 50.0 % of cases when both S2 were spared; and in 70 % of cases when one S3 was spared; if both S3 were spared, bowel function was normal in 94 % of cases. When even one S4 root was spared, normal bladder and bowel function were present in 100 % of cases. Unilateral sacral nerve root resection preserved normal bladder function in 75 % of cases and normal bowel function in 82.6 % of cases. Motor function depended on S1 root involvement. CONCLUSION: Total sacrectomy is associated with compromising important motor, bladder, bowel, sensitivity, and sexual function. Residual motor function is dependent on sparing L5 and S1 nerve roots. Bladder and bowel function is consistently compromised in higher sacrectomies; nevertheless, the probability of maintaining sufficient function increases progressively with the roots spared, especially when S3 nerve roots are spared. Unilateral resection is usually associated with more normal function. To the best of our knowledge, this is the first comprehensive literature review to analyze published reports of residual sacral nerve root function after sacrectomy.

The Tokuhashi score: effectiveness and pitfalls.

PURPOSE: Accurate survival estimation is prerequisite to determine the most appropriate treatment for patients with metastatic spine disease. Several authors have proposed classification systems analyzing clinical and radiological parameters, such as, performance status, metastasis localization, and primary tumor histotype, but the modified Tokuhashi score (mTS) is the most widely used. Although it is regarded as one of the most complete and accurate systems, it does not take the effectiveness of new therapeutic strategies into consideration, contributing to a progressive loss of accuracy. The purpose of this review is to verify the ability of the mTS to accurately estimate metastatic spine patient survival, nearly 10 years after it was introduced. METHODS: A literature review was conducted to evaluate mTS accuracy to predict metastatic spine patient survival. RESULTS: Ten studies were selected, representing 1686 patients. The total predictive accuracy of the mTS was 63.00%; for patients expected to survive less than 6 months (group I), it was 64.10%; 6-12 months (group II), 55.32%; and more than 12 months (group III), 77.21%. A progressive decrease in accuracy over time was statistically significant in groups I and II. CONCLUSIONS: The mTS is suggestive of actual survival for patients with a good prognosis. It is less accurate for patients with an estimated survival of less than 12 months. The decreasing trend in mTS accuracy over time will likely further reduce mTS utility. An important opportunity exists to develop new instruments to assist spine surgeons and oncologists to choose appropriate surgical or non-surgical treatment modalities for patients with metastatic spine disease.

The surgical neurovascular anatomy relating to partial and complete sacral and sacroiliac resections: a cadaveric, anatomic study.

PURPOSE: Pelvic and sacral surgeries are considered technically difficult due to the complex multidimensional anatomy and the presence of significant neurovascular structures. Knowledge of the key neurovascular anatomy is essential for safe and effective execution of partial and complete sacral resections. The goal of this anatomic, cadaveric study is to describe the pertinent neurovascular anatomy during these procedures. METHODS: Three embalmed human cadaveric specimens were used. Sacrectomies and sacroiliac joint resections were simulated and the structures at risk were identified. Both anterior and posterior approaches were evaluated. RESULTS: During sacroiliac joint resection, L5 nerve roots are at high risk for iatrogenic injury; the vasculatures at greatest risk are the common iliac vessels and internal iliac vessels with L5-S1 and S1-S2 high sacrectomies. Minor bleeding risk is associated with S2-S3 osteotomy because of the potential to damage superior gluteal vessels. S3-S4 osteotomy presents a low risk of bleeding. Adjacent nerve roots proximal to the resection level are at high risk during higher sacrectomies. CONCLUSIONS: Several sacrectomy techniques are available and selection often depends on the specific case and surgeon preference; nevertheless, anatomic knowledge is extremely important. Considering the highly variable anatomic relations of the vascular bundles, a preoperative evaluation with CT or MRI with vascular reconstruction may be helpful to decrease bleeding risk by preemptively binding the internal iliac vessels in cases where higher tumors are present. To decrease the risk of damaging nerve roots, it is recommended to perform the resection as close to the involved foramina as possible.

The role of minimally invasive lateral lumbar interbody fusion in sagittal balance correction and spinal deformity.

PURPOSE: The recent proliferation of minimally invasive lateral lumbar interbody fusion (LLIF) techniques has drawn attention to potential for these techniques to control or correct sagittal misalignment in adult spinal deformity. We systemically reviewed published studies related to LLIF use in adult spinal deformity treatment with emphasis on radiographic assessment of sagittal balance. METHODS: A literature review was conducted to examine studies focusing on sagittal balance restoration in adult degenerative scoliosis with the LLIF approach. RESULTS: Fourteen publications, 12 retrospective and 2 prospective, reported data regarding lumbar lordosis correction (1,266 levels in 476 patients) but only two measured global sagittal alignment. CONCLUSION: LLIF appears to be especially effective when the lumbar lordosis and sagittal balance correction goals are less than 10° and 5 cm, respectively. However, the review demonstrated a lack of consistent reporting on sagittal balance restoration with the MIS LLIF techniques.

Emotional facial expression and perioral motor functions of the human auditory cortex.

OBJECTIVE: We investigated the role of transverse temporal gyrus and adjacent cortex (TTG+) in facial expressions and perioral movements. METHODS: In 31 patients undergoing stereo-electroencephalography monitoring, we describe behavioral responses elicited by electrical stimulation within the TTG+. Task-induced high-gamma modulation (HGM), auditory evoked responses, and resting-state connectivity were used to investigate the cortical sites having different types of responses on electrical stimulation. RESULTS: Changes in facial expressions and perioral movements were elicited on electrical stimulation within TTG+ in 9 (29%) and 10 (32%) patients, respectively, in addition to the more common language responses (naming interruptions, auditory hallucinations, paraphasic errors). All functional sites showed auditory task induced HGM and evoked responses validating their location within the auditory cortex, however, motor sites showed lower peak amplitudes and longer peak latencies compared to language sites. Significant first-degree connections for motor sites included precentral, anterior cingulate, parahippocampal, and anterior insular gyri, whereas those for language sites included posterior superior temporal, posterior middle temporal, inferior frontal, supramarginal, and angular gyri. CONCLUSIONS: Multimodal data suggests that TTG+ may participate in auditory-motor integration. SIGNIFICANCE: TTG+ likely participates in facial expressions in response to emotional cues during an auditory discourse.

Exclusively endoscopic management of complicated pineal cysts in young children: Definitive treatment through single burr-hole technique.

Background: The management of complicated symptomatic pineal cysts in the pediatric population is challenging and variable. Surgical management may include treatment of hydrocephalus alone, or direct treatment of the cyst with or without direct hydrocephalus management. This is typically done through craniotomy-based microsurgical approaches to the pineal region or an endoscopic transventricular approach. Methods: We present a stepwise minimally invasive technique to treat complicated pineal cysts in young children associated with an obstructive hydrocephalus in a single procedure through third ventriculostomy combined with an intraventricular marsupialization of the pineal cyst through a single burr-hole using stereotactic navigation. Results: Two young patients with over 2 years of follow-up have done well without complication using this technique. Other literature reports for complex pineal cysts in pediatric patients are reviewed and this technique is not previously described for this population. Conclusion: Endoscopic third ventriculostomy and cyst marsupialization using a single burr-hole and stereotactic navigation for symptomatic or enlarging pineal cysts in children allow for minimally invasive management, a rapid recovery, short hospital stay, and durable outcome owed to redundant CSF flow pathways.

Improving Detection of Hippocampal Epileptiform Activity Using Magnetoencephalography.

PURPOSE: Magnetoencephalography (MEG) defines the spike-generating zone and provides targets for invasive monitoring with stereotactic electroencephalography. This retrospective, blinded, cross-sectional study determined whether MEG virtual sensors could identify hippocampal epileptiform activity. METHODS: Using MEG beamformer analysis, virtual sensors were manually placed in bilateral hippocampi and corresponding virtual sensor waveforms were analyzed for the presence of epileptiform activity. These findings were compared with hippocampal stereotactic electroencephalography in the same patients. Concordance was determined using sensitivity and specificity. RESULTS: Thirty patients (mean age 12.5 ± 5.9 years) and 35 hippocampi were included. Patients were also placed into subgroups based on conventional MEG analysis: temporal (n = 19), extratemporal (n = 10), and normal (n = 1). Overall, sensitivity and specificity were 57.9% and 50.0%, respectively (n = 35). Patients with temporal sources based on conventional MEG analysis had sensitivity and specificity of 80.0% and 36.4%, respectively (n = 21). Those with extratemporal sources based on conventional MEG had sensitivity and specificity of 42.9% and 80.0%, respectively (n = 12). CONCLUSIONS: When grouped by conventional MEG analysis, virtual sensors can be useful to confirm mesial temporal dipoles seen with conventional analysis. SIGNIFICANCE: This work may help support the use of MEG for the detection of epileptiform activity in the hippocampus and influence the planning of invasive electrode placement.

Neuronal Circuits Supporting Development of Visual Naming Revealed by Intracranial Coherence Modulations.

Background: Improvement in visual naming abilities throughout the childhood and adolescence supports development of higher-order linguistic skills. We investigated neuronal circuits underlying improvement in the speed of visual naming with age, and age-related dynamics of these circuits. Methods: Response times were electronically measured during an overt visual naming task in epilepsy patients undergoing stereo-EEG monitoring. Coherence modulations among pairs of neuroanatomic parcels were computed and analyzed for relationship with response time and age. Results: During the overt visual naming task, mean response time (latency) significantly decreased from 4 to 23 years of age. Coherence modulations during visual naming showed that increased connectivity between certain brain regions, particularly that between left fusiform gyrus/left parahippocampal gyrus and left frontal operculum, is associated with improvement in naming speed. Also, decreased connectivity in other brain regions, particularly between left angular and supramarginal gyri, is associated with decreased mean response time. Further, coherence modulations between left frontal operculum and both left fusiform and left posterior cingulate gyri significantly increase, while that between left angular and supramarginal gyri significantly decrease, with age. Conclusion: Naming speed continues to improve from pre-school years into young adulthood. This age-related improvement in efficiency of naming environmental objects occurs likely because of strengthened direct connectivity between semantic and phonological nodes, and elimination of intermediate higher-order cognitive steps.

Posterior Quadrant Disconnection Procedure for Intractable Epilepsy: A Case Series of 5 Young Pediatric Patients.

BACKGROUND: Posterior quadrant disconnection (PQD) has been described as a treatment for patients with refractory posterior quadrant subhemispheric epilepsy. Surgical outcomes are difficult to interpret because of limited literature. OBJECTIVE: To provide insight regarding the operative technique and postsurgical seizure freedom in young pediatric patients who underwent surgical disconnection for the treatment of posterior quadrant subhemispheric epilepsy at our institution. METHODS: The authors retrospectively analyzed a series of 5 patients who underwent PQD between 2019 and 2021. Charts were reviewed for preoperative workup including noninvasive/invasive testing, operative reports, and postoperative follow-up data which included degree of seizure freedom, completion of disconnection, and complications. RESULTS: Five patients were included in this series. The median age at seizure onset was 12 months (range 3-24 months), and the median age at surgery was 36 months (range 22-72 months). Histopathology confirmed focal cortical dysplasia in 3 of 5 patients (2 patients with type IB; 1 with type IIID). The average length of follow-up after surgery was 16.8 months (range 12-24 months). All patients underwent complete disconnection of the posterior quadrant without complications. Four of 5 patients (80%) had Engel score of I, while the remaining patient had an Engel score of IIB. CONCLUSION: Our early results demonstrate that complete PQD can be successful at providing excellent seizure freedom and functional outcomes in carefully selected young pediatric patients who have concordant seizure semiology, noninvasive/invasive testing, and imaging findings with primary seizure onset zone within the ipsilateral posterior quadrant. Meticulous surgical planning and thorough understanding of the surgical anatomy and technique are critical to achieving complete disconnection.