Objective: Pediatric low-grade gliomas (LGGs) are found in approximately one to three percent of patients with childhood epilepsy. Epilepsy in these patients is often medically refractory and therefore represents a unique cohort with significant morbidity from concomitant pathology. Similar studies in adult patients with low-grade gliomas have identified predictors of seizure freedom including gross-total resection, preoperative seizure control on antiepileptic medication and duration of seizures of less than one year. This study aims to identify similar predictors of seizure freedom in operatively managed pediatric LGGs.
GammaTile® (GT Medical Technologies, Tempe, Arizona) is a surgically targeted radiation source, approved by FDA for brachytherapy in primary and secondary brain neoplasms. Each GammaTile is composed of a collagen sponge with four seeds of cesium 131 and is particularly useful in recurrent tumors. We report our early experience in seven patients with recurrent gliomas to assess this type of brachytherapy with particular attention to ease of use, complication, and surgical planning. This study represents a retrospective chart review of surgical use and early clinical outcomes of GammaTile in recurrent gliomas. The number of tiles was planned using pre-operative imaging and dosimetry was planned based on post-operative imaging. Patients were followed during their hospital stay and were followed up after discharge. Parameters such as case length, resection extent, complication, ICU length of stay (LOS), hospital LOS, pre-operative Glasgow Coma Scale (GCS), immediate post-operative GCS, post-operative imaging findings, recurrence at follow-up, length of follow-up, and dosimetry were collected in a retrospective manner. Seven patients were identified that met the inclusion criteria. Two patients were diagnosed with recurrent glioblastoma multiforme (GBM), one lower-grade glioma that recurred as a GBM, one GBM that recurred as a gliosarcoma, and two recurrent oligodendrogliomas. We found that operation time, ICU LOS, hospital LOS, pre- and post-operative GCS, and post-operative complications were within the expected ranges for tumor resection patients. Further, dosimetry data suggests that six out of seven patients received adequate radiation coverage, with the seventh having implantation limitations due to nearby organs at risk. We report no postoperative complications that can be attributed to the GammaTiles themselves. In our cohort, we report seven cases where GammaTiles were implanted in recurrent gliomas. No implant-related post-operative complications were identified. This early data suggests that GammaTile can be a safe form of brachytherapy in recurrent gliomas.
MR-guided laser interstitial therapy (MRgLITT) is becoming more commonly used for minimal access approaches to intracranial lesions of all etiologies. The short-term safety profile of MRgLITT is favorable compared with sweeping incisions and open craniotomies, especially for lesions located in deep, periventricular, and highly eloquent areas. The Visualase software (Medtronic Inc., Minneapolis, MN, USA) has multiple adaptations to assist with this safety margin, including the thermal damage estimate (TDE), which applies predictive mathematical modeling to a two-dimensional (2D) graphical representation. TDE has been shown to highly correlate with actual tissue destruction in a priori MRgLITT cases and to anecdotally be imprecise when MRgLITT is combined with biopsy. We present a case regarding a 17-year-old male patient with intractable focal epilepsy. He underwent stereotactic biopsy and then ablation where it was shown that TDE is ~35% larger in the coronal plane than in the actual ablation zone. Air may have caused this artifact in the biopsy cavity, which affected the proton resonance frequency (PRF) and caused TDE pigment deposition. We believe in the need for a more comprehensive understanding and investigation regarding this TDE artifact. Future prospective studies into MRgLITT should attend carefully in cases where it is combined with biopsy.
In the molecular era of neuro-oncology, it is increasingly necessary to obtain tissue for next-generation sequencing and methylome profile for prognosis and targeted oncological management. Brainstem tumors can be technically challenging to biopsy in the pediatric population. Frame-based and frameless techniques have previously been described and proven to be safe and efficacious in children. Recent cranial robotic guidance platforms have augmented the fluency of frameless stereotactic approaches, but the technical nuances of these procedures in children are not often discussed. We present a technical workflow for frameless stereotactic biopsy of brainstem tumors in children using the Medtronic Stealth Autoguide cranial robotic guidance platform and examine safety and efficacy of this surgical approach.
BACKGROUND AND OBJECTIVES: Robot-assisted stereoelectroencephalography (sEEG) is steadily supplanting traditional frameless and frame-based modalities for minimally invasive depth electrode placement in epilepsy workup. Accuracy rates similar to gold-standard frame-based techniques have been achieved, with improved operative efficiency. Limitations in cranial fixation and placement of trajectories in pediatric patients are believed to contribute to a time-dependent accumulation of stereotactic error. Thus, we aim to study the impact of time as a marker of cumulative stereotactic error during robotic sEEG. METHODS: All patients between October 2018 and June 2022 who underwent robotic sEEG were included. Radial errors at entry and target points as well as depth and Euclidean distance errors were collected for each electrode, excluding those with errors over 10 mm. Target point errors were standardized by planned trajectory length. ANOVA and error rates over time were analyzed using GraphPad Prism 9. RESULTS: Forty-four patients met inclusion criteria for a total of 539 trajectories. Number of electrodes placed ranged from 6 to 22. Average root mean squared error was 0.45 ± 0.12 mm. Average entry, target, depth, and Euclidean distance errors were 1.12 ± 0.41 mm, 1.46 ± 0.44 mm, −1.06 ± 1.43 mm, and 3.01 ± 0.71 mm, respectively. There was no significant increased error with each sequential electrode placed (entry error P -value = .54, target error P -value = .13, depth error P -value = .22, Euclidean distance P -value = .27). CONCLUSION: No decremental accuracy over time was observed. This may be secondary to our workflow which prioritizes oblique and longer trajectories first and then into less error-prone trajectories. Further study on the effect of level of training may reveal a novel difference in error rates.
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Cerebral vasospasm is a rare life-threatening complication of transsphenoidal surgery (TSS). We report our experience with two cases of symptomatic vasospasm after endoscopic TSS, alongside a systematic review of published cases. Two patients who underwent endoscopic TSS for resection of a tuberculum sella meningioma (case 1) and pituitary adenoma (case 2) developed symptomatic vasospasm. Clinical variables, including demographics, histopathology, the extent of subarachnoid hemorrhage (SAH), diabetes insipidus (DI), day of vasospasm, vasospasm symptoms, vessels involved, management, and clinical outcome, were retrospectively extracted. We subsequently reviewed published cases of symptomatic post-TSS vasospasm. Including our two cases, we identified 34 reported cases of TSS complicated by symptomatic vasospasm. Female patients accounted for 20 (58.8%) of 34 cases. The average age was 48.1 ± 12.9 years. The majority of patients exhibited postoperative SAH (70.6%). The average delay to vasospasm presentation was 8.5 ± 3.6 days. The majority of patients exhibited vasospasm in multiple vessels, typically involving the anterior circulation. Hemodynamic augmentation with hemodilution, hypertension, and hypervolemia was the most common treatment. Death occurred in six (17.6%) of 34 patients. Common deficits included residual extremity weakness (17.6%), pituitary insufficiency (8.8%), and cognitive deficits (8.8%). Symptomatic vasospasm is a rare, potentially fatal complication of TSS. The most consistent risk factor is SAH. Early diagnosis requires a high index of suspicion when confronted with intractable DI, acute mental status change, or focal deficits in the days after TSS. Morbidity and death are significant risks in patients with this complication.
OBJECTIVE Neuropathic pain is undertreated in children. Neurosurgical treatments of pediatric chronic pain are limited by the absence of both US Food and Drug Administration approval and pediatric-specific hardware, as well as weak referral patterns due to a lack of physician education. This study presents a single-institution retrospective case series of spinal cord stimulation (SCS) in children ≤ 19 years of age and a systematic review of SCS in children. The authors’ findings may further validate the role of SCS as an effective treatment modality for varied neuropathic pain syndromes found in pediatric patients. METHODS The study was a single-center, single-surgeon, retrospective case series of individuals treated between July 2017 and May 2022. The outcomes for pediatric patients with chronic neuropathic pain syndromes indicated by the multidisciplinary pain clinic for evaluation for SCS were cataloged. A systematic review and individual participant data (IPD) meta-analysis was performed for cases treated until May 2022, using PubMed, EMBASE, and Scopus to characterize outcomes of children with neuropathic pain treated with SCS. RESULTS Twelve patients were evaluated and 9 were indicated for percutaneous or buried lead trials. Seven female and 2 male patients between the ages of 13 and 19 years were implanted with trial leads. Eight of 9 (89%) patients went on to receive permanent systems. The average trial length was 6 days, and the length of stay for both trial and implant was less than 1 day. Complication rates due to CSF leaks were 22% and 0% for trial and implant, respectively. Visual analog scale pain scores decreased from 9.2 to 2.9 (p = 0.0002) and the number of medications decreased from 4.9 to 2.1 (p = 0.0005). Functional status also improved for each patient. A systematic review identified 13 studies describing pediatric patients with SCS, including 12 providing IPD on 30 patients. In the IPD meta-analysis, pain was reduced in 16/16 (100%) of patients following surgery and in 25/26 (96.2%) at last follow-up. Medication use was decreased in 16/21 (76.2%), and functional outcomes were improved in 29/29 (100%). The complication rate was 5/30 (16.7%). CONCLUSIONS SCS effectively decreases pain and medication use for pediatric neuropathic pain syndromes. Patients also report improved functional status, including improved matriculation, gainful employment, and physical activity. There is minimal high-quality literature describing neuromodulation for pain in children. Neuromodulation should be considered earlier as a viable alternative to escalating use of multiple drugs and as a potential mechanism to address tolerance, dependence, and addiction in pediatric patients.
