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Editorial. Head shape at 36 months with and without helmeting

Matthew D. Smyth

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Resting-state functional magnetic resonance imaging for surgical planning in pediatric patients: a preliminary experience

Jarod L. Roland, Natalie Griffin, Carl D. Hacker, Ananth K. Vellimana, S. Hassan Akbari, Joshua S. Shimony, Matthew D. Smyth, Eric C. Leuthardt, and David D. Limbrick Jr.

OBJECTIVE

Cerebral mapping for surgical planning and operative guidance is a challenging task in neurosurgery. Pediatric patients are often poor candidates for many modern mapping techniques because of inability to cooperate due to their immature age, cognitive deficits, or other factors. Resting-state functional MRI (rs-fMRI) is uniquely suited to benefit pediatric patients because it is inherently noninvasive and does not require task performance or significant cooperation. Recent advances in the field have made mapping cerebral networks possible on an individual basis for use in clinical decision making. The authors present their initial experience translating rs-fMRI into clinical practice for surgical planning in pediatric patients.

METHODS

The authors retrospectively reviewed cases in which the rs-fMRI analysis technique was used prior to craniotomy in pediatric patients undergoing surgery in their institution. Resting-state analysis was performed using a previously trained machine-learning algorithm for identification of resting-state networks on an individual basis. Network maps were uploaded to the clinical imaging and surgical navigation systems. Patient demographic and clinical characteristics, including need for sedation during imaging and use of task-based fMRI, were also recorded.

RESULTS

Twenty patients underwent rs-fMRI prior to craniotomy between December 2013 and June 2016. Their ages ranged from 1.9 to 18.4 years, and 12 were male. Five of the 20 patients also underwent task-based fMRI and one underwent awake craniotomy. Six patients required sedation to tolerate MRI acquisition, including resting-state sequences. Exemplar cases are presented including anatomical and resting-state functional imaging.

CONCLUSIONS

Resting-state fMRI is a rapidly advancing field of study allowing for whole brain analysis by a noninvasive modality. It is applicable to a wide range of patients and effective even under general anesthesia. The nature of resting-state analysis precludes any need for task cooperation. These features make rs-fMRI an ideal technology for cerebral mapping in pediatric neurosurgical patients. This review of the use of rs-fMRI mapping in an initial pediatric case series demonstrates the feasibility of utilizing this technique in pediatric neurosurgical patients. The preliminary experience presented here is a first step in translating this technique to a broader clinical practice.

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One hundred consecutive endoscopic repairs of sagittal craniosynostosis: an evolution in care

Dennis C. Nguyen, Scott J. Farber, Gary B. Skolnick, Sybill D. Naidoo, Matthew D. Smyth, Alex A. Kane, Kamlesh B. Patel, and Albert S. Woo

OBJECTIVE

Endoscope-assisted repair of sagittal craniosynostosis was adopted at St. Louis Children’s Hospital in 2006. This study examines the first 100 cases and reviews the outcomes and evolution of patient care protocols at our institution.

METHODS

The authors performed a retrospective chart review of the first 100 consecutive endoscopic repairs of sagittal craniosynostosis between 2006 and 2014. The data associated with length of hospital stay, blood loss, transfusion rates, operative times, cephalic indices (CIs), complications, and cranial remolding orthosis were reviewed. Measurements were taken from available preoperative and 1-year postoperative 3D reconstructed CT scans.

RESULTS

The patients’ mean age at surgery was 3.3 ± 1.1 months. Of the 100 patients, 30 were female and 70 were male. The following perioperative data were noted. The mean operative time (± SD) was 77.1 ± 22.2 minutes, the mean estimated blood loss was 34.0 ± 34.8 ml, and the mean length of stay was 1.1 ± 0.4 days; 9% of patients required transfusions; and the mean pre- and postoperative CI values were 69.1 ± 3.8 and 77.7 ± 4.2, respectively. Conversion to open technique was required in 1 case due to presence of a large emissary vein that was difficult to control endoscopically. The mean duration of helmet therapy was 8.0 ± 2.9 months. Parietal osteotomies were eventually excluded from the procedure.

CONCLUSIONS

The clinical outcomes and improvements in CI seen in our population are similar to those seen at other high-volume centers. Since the inception of endoscope-assisted repair at our institution, the patient care protocol has undergone several significant changes. We have been able to remove less cranium using our “narrow-vertex” suturectomy technique without affecting patient safety or outcome. Patient compliance with helmet therapy and collaborative care with the orthotists remain the most essential aspects of a successful outcome.

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Applications of a robotic stereotactic arm for pediatric epilepsy and neurooncology surgery

Brandon A. Miller, Afshin Salehi, David D. Limbrick Jr., and Matthew D. Smyth

OBJECTIVE

The ROSA device is a robotic stereotactic arm that uses a laser system to register the patient’s head or spine with MR or CT images. In this study, the authors analyze their experience with this system in pediatric neurosurgical applications and present selected cases that exemplify the usefulness of this system.

METHODS

The authors reviewed all cases that utilized the ROSA system at their institution. Patient demographics, pathology, complications, electrode placement, laser ablation, and biopsy accuracy were analyzed. Patient disposition and condition at follow-up were also analyzed.

RESULTS

Seventeen patients underwent 23 procedures using the ROSA system. A total of 87 electroencephalography electrodes were placed, with 13% deviating more than 3 mm from target. Six patients underwent stereotactic needle biopsy, and 9 underwent laser interstitial thermotherapy (LITT). One patient who underwent LITT required a subsequent craniotomy for tumor resection. Another patient experienced an asymptomatic extraaxial hematoma that spontaneously resolved. No patient suffered neurological complications during follow-up. Follow-up from the last procedure averaged 180 days in epilepsy patients and 309 days in oncology patients.

CONCLUSIONS

The precision, ease of use, and versatility of the ROSA system make it well suited for pediatric neurosurgical practice. Further work, including long-term analysis of results and cost-effectiveness, will help determine the utility of this system and if its applications can be expanded.

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Hydrocephalus presenting as idiopathic aqueductal stenosis with subsequent development of obstructive tumor: report of 2 cases demonstrating the importance of serial imaging

Jarod L. Roland, Richard L. Price, Ashwin A. Kamath, S. Hassan Akbari, Eric C. Leuthardt, Brandon A. Miller, and Matthew D. Smyth

The authors describe 2 cases of triventricular hydrocephalus initially presenting as aqueductal stenosis that subsequently developed tumors of the pineal and tectal region. The first case resembled late-onset idiopathic aqueductal stenosis on serial imaging. Subsequent imaging revealed a new tumor in the pineal region causing mass effect on the midbrain. The second case presented in a more typical pattern of aqueductal stenosis during infancy. On delayed follow-up imaging, an enlarging tectal mass was discovered. In both cases hydrocephalus was successfully treated by cerebrospinal fluid diversion prior to tumor presentation. The differential diagnoses, diagnostic testing, and treatment course for these unusual cases are discussed. The importance of follow-up MRI in cases of idiopathic aqueductal stenosis is emphasized by these exemplar cases.

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The use of hippocampal volumetric measurements to improve diagnostic accuracy in pediatric patients with mesial temporal sclerosis

Gloria J. Guzmán Pérez-Carrillo, Christopher Owen, Katherine E. Schwetye, Spencer McFarlane, Ananth K. Vellimana, Soe Mar, Michelle M. Miller-Thomas, Joshua S. Shimony, Matthew D. Smyth, and Tammie L. S. Benzinger

OBJECTIVE

Many patients with medically intractable epilepsy have mesial temporal sclerosis (MTS), which significantly affects their quality of life. The surgical excision of MTS lesions can result in marked improvement or even complete resolution of the epileptic episodes. Reliable radiological diagnosis of MTS is a clinical challenge. The purpose of this study was to evaluate the utility of volumetric mapping of the hippocampi for the identification of MTS in a case-controlled series of pediatric patients who underwent resection for medically refractory epilepsy, using pathology as a gold standard.

METHODS

A cohort of 57 pediatric patients who underwent resection for medically intractable epilepsy between 2005 and 2015 was evaluated. On pathological investigation, this group included 24 patients with MTS and 33 patients with non-MTS findings. Retrospective quantitative volumetric measurements of the hippocampi were acquired for 37 of these 57 patients. Two neuroradiologists with more than 10 years of experience who were blinded to the patients' MTS status performed the retrospective review of MR images. To produce the volumetric data, MR scans were parcellated and segmented using the FreeSurfer software suite. Hippocampal regions of interest were compared against an age-weighted local regression curve generated with data from the pediatric normal cohort. Standard deviations and percentiles of specific subjects were calculated. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined for the original clinical read and the expert readers. Receiver operating characteristic curves were generated for the methods of classification to compare results from the readers with the authors' results, and an optimal threshold was determined. From that threshold the sensitivity, specificity, PPV, and NPV were calculated for the volumetric analysis.

RESULTS

With the use of quantitative volumetry, a sensitivity of 72%, a specificity of 95%, a PPV of 93%, an NPV of 78%, and an area under the curve of 0.84 were obtained using a percentage difference of normalized hippocampal volume. The resulting specificity (95%) and PPV (93%) are superior to the original clinical read and to Reader A and Reader B's findings (range for specificity 74%–86% and for PPV 64%–71%). The sensitivity (72%) and NPV (78%) are comparable to Reader A's findings (73% and 81%, respectively) and are better than those of the original clinical read and of Reader B (sensitivity 45% and 63% and NPV 71% and 70%, respectively).

CONCLUSIONS

Volumetric measurement of the hippocampi outperforms expert readers in specificity and PPV, and it demonstrates comparable to superior sensitivity and NPV. Volumetric measurements can complement anatomical imaging for the identification of MTS, much like a computer-aided detection tool would. The implementation of this approach in the daily clinical workflow could significantly improve diagnostic accuracy.

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Hemispherotomy in children with electrical status epilepticus of sleep

Anna Jeong, Jennifer Strahle, Ananth K. Vellimana, David D. Limbrick Jr., Matthew D. Smyth, and Mary Bertrand

OBJECTIVE

Electrical status epilepticus of sleep (ESES) is a rare electrographic pattern associated with global regression, which is often poorly responsive to traditional epilepsy treatments and can have a devastating and permanent neurocognitive outcome. The authors analyzed clinical, electroencephalographic, and neuropsychological outcomes in 9 patients with refractory ESES treated with functional hemispherotomy to illustrate the wide clinical spectrum associated with the disease and explore the role of hemispherotomy in its treatment.

METHODS

During the period between 2003 and 2015, 80 patients underwent hemispherotomy at the authors' institution. Video electroencephalography (EEG) reports were reviewed for ESES or continuous spikes and waves during sleep (CSWS). Patients with preoperative ESES (> 85% slow-wave sleep occupied by spike waves), a unilateral structural lesion amenable to surgery, and more than 6 months of follow-up data were included in the analysis. Clinical data, EEG recordings, neuropsychological testing, and parental and clinician reports were retrospectively reviewed.

RESULTS

Nine patients were eligible for study inclusion. Age at seizure onset ranged from birth to 4.2 years (mean 1.9 years), age at ESES diagnosis ranged from 3.5 to 8.8 years (mean 6.0 years), and age at hemispherotomy ranged from 3.7 to 11.5 years (mean 6.8 years). All patients had drug-resistant epilepsy. The duration of epilepsy prior to hemispherotomy ranged from 2.7 to 8.9 years (mean ± SD, 5.0 ± 2.2 years). Engel Class I seizure outcome was observed in all 9 children, with a mean follow-up of 3.0 years (range 0.5–6.1 years). Hemispherotomy terminated ESES in 6 of 6 patients with available postoperative sleep EEG. All children had preoperative neuropsychological impairments. Developmental regression was halted postoperatively, but none of the children returned to their original pre-ESES baseline. Four children demonstrated academic gains, 2 of whom transitioned to mainstream classes.

CONCLUSIONS

Children with drug-resistant ESES and a unilateral structural lesion should be evaluated for hemispherotomy as they may experience the cessation of seizures, termination of ESES, and improvement in neuropsychological status.

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Endoscope-assisted management of sagittal synostosis: wide vertex suturectomy and barrel stave osteotomies versus narrow vertex suturectomy

Brian J. Dlouhy, Dennis C. Nguyen, Kamlesh B. Patel, Gwendolyn M. Hoben, Gary B. Skolnick, Sybill D. Naidoo, Albert S. Woo, and Matthew D. Smyth

OBJECTIVE

Endoscope-assisted methods for treatment of craniosynostosis have reported benefits over open calvarial vault reconstruction. In this paper, the authors evaluated 2 methods for endoscope-assisted correction of sagittal synostosis: wide vertex suturectomy and barrel stave osteotomies (WVS+BSO) and narrow vertex suturectomy (NVS).

METHODS

The authors evaluated patients with nonsyndromic sagittal synostosis treated with either wide vertex suturectomy (4–6 cm) and barrel stave osteotomies (WVS+BSO) or narrow vertex suturectomy (NVS) (approximately 2 cm) between October 2006 and July 2013. Prospectively collected data included patient age, sex, operative time, estimated blood loss (EBL), postoperative hemoglobin level, number of transfusions, complications, and cephalic index. Fourteen patients in the NVS group were age matched to 14 patients in the WVS+BSO group. Descriptive statistics were calculated, and Student t-tests were used to compare prospectively obtained data from the WVS+BSO group with the NVS group in a series of univariate analyses.

RESULTS

The mean age at surgery was 3.9 months for WVS+BSO and 3.8 months for NVS. The mean operative time for patients undergoing NVS was 59.0 minutes, significantly less than the 83.4-minute operative time for patients undergoing WVS+BSO (p < 0.05). The differences in mean EBL (NVS: 25.4 ml; WVS+BSO: 27.5 ml), mean postoperative hemoglobin level (NVS: 8.6 g/dl; WVS+BSO: 8.0 g/dl), mean preoperative cephalic index (NVS: 69.9; WVS+BSO: 68.2), and mean cephalic index at 1 year of age (NVS: 78.1; WVS+BSO: 77.2) were not statistically significant.

CONCLUSIONS

The NVS and WVS+BSO produced nearly identical clinical results, as cephalic index at 1 year of age was similar between the 2 approaches. However, the NVS required fewer procedural steps and significantly less operative time than the WVS+BSO. The NVS group obtained the final cephalic index in a similar amount of time postoperatively as the WVS+BSO group. Complications, transfusion rates, and EBL were not different between the 2 techniques.

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Laser interstitial thermal therapy for subependymal giant cell astrocytoma: technical case report

David Y. A. Dadey, Ashwin A. Kamath, Eric C. Leuthardt, and Matthew D. Smyth

Subependymal giant cell astrocytoma (SEGA) is a rare tumor occurring almost exclusively in patients with tuberous sclerosis complex. Although open resection remains the standard therapy, complication rates remain high. To minimize morbidity, less invasive approaches, such as endoscope-assisted resection, radiosurgery, and chemotherapy with mTOR pathway inhibitors, are also used to treat these lesions. Laser interstitial thermal therapy (LITT) is a relatively new modality that is increasingly used to treat a variety of intracranial lesions. In this report, the authors describe two pediatric cases of SEGA that were treated with LITT. In both patients the lesion responded well to this treatment modality, with tumor shrinkage observed on follow-up MRI. These cases highlight the potential of LITT to serve as a viable minimally invasive therapeutic approach to the management of SEGAs in the pediatric population.

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Utilizing personalized stereotactic frames for laser interstitial thermal ablation of posterior fossa and mesiotemporal brain lesions: a single-institution series

David Y. A. Dadey, Ashwin A. Kamath, Matthew D. Smyth, Michael R. Chicoine, Eric C. Leuthardt, and Albert H. Kim

OBJECTIVE

The precision of laser probe insertion for interstitial thermal therapy of deep-seated lesions is limited by the method of stereotactic guidance. The objective of this study was to evaluate the feasibility of customized STarFix 3D-printed stereotactic platforms to guide laser probe insertion into mesiotemporal and posterior fossa targets.

METHODS

The authors conducted a retrospective review of 5 patients (12–55 years of age) treated with laser interstitial thermal therapy (LITT) in which STarFix platforms were used for probe insertion. Bone fiducials were implanted in each patient's skull, and subsequent CT scans were used to guide the design of each platform and incorporate desired treatment trajectories. Once generated, the platforms were mounted on the patients' craniums and used to position the laser probe during surgery. Placement of the laser probe and the LITT procedure were monitored with intraoperative MRI. Perioperative and follow-up MRI were performed to identify and monitor changes in target lesions.

RESULTS

Accurate placement of the laser probe was observed in all cases. For all patients, thermal ablation was accomplished without intraoperative complications. Of the 4 patients with symptomatic lesions, 2 experienced complete resolution of symptoms, and 1 reported improved symptoms compared with baseline.

CONCLUSIONS

Customized stereotactic platforms were seamlessly incorporated into the authors' previously established LITT workflow and allowed for accurate treatment delivery.