Accuracy and Safety of Customized Stereotactic Fixtures for Stereoelectroencephalography in Pediatric Patients.

Stereoelectroencephalography (SEEG) in children with intractable epilepsy presents particular challenges. Their thin and partially ossified cranium, specifically in the temporal area, is prone to fracture while attaching stereotactic systems to the head or stabilizing the head in robot's field of action. Postponing SEEG in this special population of patients can have serious consequences, reducing their chances of becoming seizure-free and impacting their social and cognitive development. This study demonstrates the safety and accuracy offered by a frameless personalized 3D printed stereotactic implantation system for SEEG investigations in children under 4 years of age. SEEG was carried out in a 3-year-old patient with drug-resistant focal epilepsy, based on a right temporal-perisylvian epileptogenic zone hypothesis. Fifteen intracerebral electrodes were placed using a StarFix patient-customized stereotactic fixture. The median lateral entry point localization error of the electrodes was 0.90 mm, median lateral target point localization error was 1.86 mm, median target depth error was 0.83 mm, and median target point localization error was 1.96 mm. There were no perioperative complications. SEEG data led to a tailored right temporal-insular-opercular resection, with resulting seizure freedom (Engel IA). In conclusion, patient-customized stereotactic fixtures are a safe and accurate option for SEEG exploration in young children.

A personalized stereotactic fixture for implantation of depth electrodes in stereoelectroencephalography.

BACKGROUND: The stereoelectroencephalographic (SEEG) implantation procedures still represent a challenge due to the intrinsic complexity of the method and the number of depth electrodes required. OBJECTIVES: We aim at designing and evaluating the accuracy of a custom stereotactic fixture based on the StarFix™ technology (FHC Inc., Bowdoin, ME) that significantly simplifies and optimizes the implantation of depth electrodes used in presurgical evaluation of patients with drug-resistant epilepsy. METHODS: Fiducial markers that also serve as anchors for the fixture are implanted into the patient's skull prior to surgery. A 3D fixture model is designed within the surgical planning software, with the planned trajectories incorporated in its design, aligned with the patient's anatomy. The stereotactic fixture is built using 3D laser sintering technology based on the computer-generated model. Bilateral rectangular grids of guide holes orthogonal to the midsagittal plane and centered on the midcommissural point are incorporated in the fixture design, allowing a wide selection of orthogonal trajectories. Up to two additional grids can be accommodated for targeting structures where oblique trajectories are required. The frame has no adjustable parts, this feature reducing the risk of inaccurate coordinate settings while simultaneously reducing procedure time significantly. RESULTS: We have used the fixture for the implantation of depth electrodes for presurgical evaluation of 4 patients with drug-resistant focal epilepsy, with nearly 2-fold reduction in the duration of the implantation procedure. We have obtained a high accuracy with a submillimetric mean positioning error of 0.68 mm for the anchor bolts placed at the trajectory entry point and 1.64 mm at target. CONCLUSIONS: The custom stereotactic fixture design greatly simplifies the planning procedure and significantly reduces the time in the operating room, while maintaining a high accuracy.

Acute spontaneous thoracic epidural hematoma, triggered by weight-lifting training, in a retired sportsman: case report and literature review.

INTRODUCTION: Spontaneous spinal epidural hematoma (SSEH) is a rare clinical entity, most often with acute symptomatic spinal cord compression and potentially permanent neurologic deficits. SSEH usually has surgical solutions and a good outcome after hematoma evacuation. CASE PRESENTATION: A 61-year-old professional weight-lifting coach presented to the emergency department with sudden back pain, rapidly progressive paraparesis, and neurogenic bladder, after an intense training, 5 h previously. Magnetic resonance imaging revealed a ventral thoracic epidural hematoma with significant compression at Th3-Th6. Surgical procedure was performed within the first 12 h: decompressive laminectomy from Th3 to Th7 vertebral levels and near total epidural hematoma removal. The patient improved rapidly from Th5 AIS-C to Th7 AIS-D paraplegia with independent ambulation, after the intervention. The rehabilitation program led to further improvement of the neurologic deficits and a favorable outcome, to AIS-E. DISCUSSION: Weightlifting has been reported as SSEH precipitating factor in young athletes. Our case is unique however, because the athlete was older. The underlying pathophysiological mechanism is represented by intravenous pressure changes and bleeding of the epidural venous plexus during a prolonged Valsalva maneuver, induced by strenuous, repeated efforts. Spondylosis, hypertension, and low doses of aspirin were incriminated as risk factors for SSEH. Prompt diagnosis, emergent decompressive intervention, early rehabilitation, and secondary prophylaxis were essential for a good outcome.

Co-occurrence of high-frequency oscillations and delayed responses evoked by intracranial electrical stimulation in stereo-EEG studies.

OBJECTIVE: To perform a side-by-side comparison of two epileptogenicity biomarkers, high frequency oscillations (HFOs) and delayed responses (DRs), as a result of single-pulse electrical stimulation. METHODS: We have recorded stimulation-evoked HFOs and DRs in 16 epileptic patients undergoing presurgical evaluation using the stereoelectroencephalographic method. To evaluate converging and complementary information provided by the biomarkers, we analyzed them individually and for logical "and"/"or" combinations between them. 3D maps of the biomarkers' distributions by recording location (inbound maps) and by stimulation location (outbound maps) were created to analyze their relationship with the epileptogenic structures. RESULTS: HFOs occur less frequently than DRs, by 18.7%, when counting by recording contacts, and more frequently, by 7.4%, when counting by stimulation contacts. 40.6% of the contacts exhibiting HFOs also exhibit DRs, and 44.1% of the contacts exhibiting DRs also exhibit HFOs. When combining biomarkers, there was a tradeoff between increased seizure onset zone (SOZ) sensitivity, from 21.3% to 73%, and decreased specificity, from 87.2% to 34.3%. CONCLUSIONS: There is a moderate similarity in the information provided by the DRs and HFOs. SIGNIFICANCE: The biomarkers complement each other, but there is a tradeoff between different metrics for SOZ localization.