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Direct cortical stimulation of the mesial frontal premotor cortex, including the supplementary motor area (SMA), is challenging in humans. Limited access to these brain regions impedes understanding of human premotor cortex functional organization and somatotopy.To test whether seizure onset within the SMA was associated with functional remapping of mesial frontal premotor areas in a cohort of patients with epilepsy who underwent awake brain mapping after implantation of interhemispheric subdural electrodes.Stimulation trials from 646 interhemispheric subdural electrodes were analyzed and compared between patients who had seizure onset in the SMA (n = 13) vs patients who had seizure onset outside of the SMA (n = 12). 1:1 matching with replacement between SMA and non-SMA data sets was used to ensure similar spatial distribution of electrodes. Centroids and 95% confidence regions were computed for clustered head, trunk, upper extremity, lower extremity, and vision responses. A generalized linear mixed-effects model was used to test for significant differences in the resulting functional maps. Clinical, radiographic, and histopathologic data were reviewed.After analyzing direct cortical stimulation trials from interhemispheric electrodes, we found significant displacement of the head and trunk responses in SMA compared with non-SMA patients ( P.01 for both). These differences remained significant after accounting for structural lesions, preexisting motor deficits, and seizure outcome.The somatotopy of the mesial frontal premotor regions is significantly altered in patients who have SMA-onset seizures compared with patients who have seizure onset outside of the SMA, suggesting that functional remapping can occur in these brain regions.

OBJECTIVEPediatric neurosurgery is a core component of neurosurgical residency training. Pediatric case minimums are established by the Neurosurgery Residency Review Committee of the Accreditation Council for Graduate Medical Education (ACGME). Case minimums, by themselves, allow for great variability in training between programs. There are no prior data on how the residency programs meet these requirements. The authors’ objective was to gather information on pediatric neurosurgical education among the ACGME-accredited neurosurgery training programs in order to shape further pediatric neurosurgical educational efforts.METHODSA 25-question survey about pediatric neurosurgical education was created by the Education Committee of the Section on Pediatric Neurological Surgery of the American Association of Neurological Surgeons/Congress of Neurological Surgeons and distributed to program directors of all 111 ACGME-accredited neurosurgery training programs.RESULTSThe response rate was 77% (86/111). In 55% of programs the residents are rotated to a responder-designated “freestanding” children’s hospital, and 39% of programs rotate residents to a children’s hospital within a larger adult hospital or a general hospital. There are 4 or fewer pediatric neurosurgical faculty in 91% of programs. In 12% of programs less than 100 cases are performed per year, and in 45% more than 500 are performed. In 31% of responding neurosurgery residency programs there is also a pediatric neurosurgery fellowship program supported by the same sponsoring institution. Seventy-seven percent of programs have at least one specific pediatric neurosurgery rotation, with 71% of those rotations occurring during postgraduate year 3 and 50% occurring during postgraduate year 4. The duration of pediatric rotation varies from no specific rotation to more than 1 year, with 48% of residents spending 4–6 months on a pediatric rotation and 12% spending 7–11 months. Last, 17% of programs send their residents to external sites sponsoring other residency programs for their pediatric rotation.CONCLUSIONSThere is great variety between neurosurgery training programs with regard to resident education in pediatric neurosurgery. This study’s data will serve as a baseline for future studies, and the authors hope the findings will guide further efforts in pediatric neurosurgical education in residency training programs.

Background Craniosynostosis has a known association with rickets. Because of abnormal bone development and a tendency for patients with rickets to present at an older age than most patients with craniosynostosis, repair may be complicated by inadequate cranial expansion and greater risk of sutural re-fusion. We present 2 cases of rickets-associated sagittal craniosynostosis and show the effectiveness of distraction osteogenesis in the surgical management of this condition. Case Description Two 3-year-old boys with rickets presented with sagittal synostosis and marked scaphocephalic deformity. Cranial osteotomies were performed followed by placement of 2 internal distractors. The devices were activated daily for 30 days to achieve a target transverse cranial distraction of 30 mm. A subsequent period of 10–12 weeks allowed for adequate bone consolidation. At the time of device removal, the final breadth of distraction and the quality of new bone formed was assessed. Distraction distance in both cases was verified intraoperatively to be 30 mm. Clinical examination confirmed that the distraction gaps were bridged by solid bone. The treatment protocol resulted in a significant improvement in cranial proportion in both patients, which was maintained at long-term follow-up. Estimated blood loss was high in both cases, presumably related to the hyperemic nature of rickets bone. Conclusions Distraction osteogenesis promotes bone growth and cranial remodeling in patients with craniosynostosis caused by rickets. The technique allows for continuous incremental expansion of both bone and scalp tissue. We recommend consideration of distraction osteogenesis in the treatment of older children with severe deformity related to craniosynostosis, including those with rickets.

BACKGROUND In the coming years the number of patients with cognitive disorders, such as Alzheimer disease and traumatic brain injury, is expected to dramatically increase, leading to an ever-increasing societal cost. Unfortunately, few medical and pharmacologic treatments have shown tangible benefit in the treatment of these diseases. Deep brain stimulation (DBS) is an established surgical technique to address multiple conditions, including Parkinson disease and essential tremor. Data from patients being treated with DBS, as well as those being monitored for seizures with depth electrodes, have suggested improvement in memory with electrical neuromodulation. METHODS MEDLINE was searched from inception through March 2018 using the keywords “DBS,” “Deep Brain Stimulation,” “Memory,” “Memory Modulation,” and “Cognition.” Studies evaluating the effect of DBS on memory and learning were shortlisted and reviewed. RESULTS Efforts to stimulate various nodes within the memory circuitry suggest that the variable effects may result from different mechanisms, including alteration of neural firing patterns, increased activity across several regions, and amplification of neural plasticity. Some of these targets, such as the entorhinal cortex, hippocampus, and nucleus basalis of Meynert, have shown promising results with regards to modulation of memory. CONCLUSIONS Given the aging population and increasing numbers of patients with memory impairment from neurodegenerative diseases, interest in neuromodulation for memory enhancement will likely expand. Further work should employ more sophisticated responsive stimulation parameters and precise spatial targeting that may lead to an effective stimulation strategy for memory enhancement.

Background Vagal nerve stimulators (VNs) have been in use in the United States since the 1990s as a palliative treatment option for drug-resistant epilepsy. Over time, the electrode coils wrapped around the vagus nerve become encapsulated by extensive scar tissue, making complete electrode removal challenging. We present a case series of lead revision surgeries with a unique way to remove the scar tissue around the vagus nerve, demonstrating a technique for complete electrode removal. Methods This was a case series of 9 consecutive patients who underwent complete removal of an existing VNs electrode using needle tip monopolar electrocautery. Results Complete removal of the entire VNs electrode array was achieved in all patients with no permanent complications seen at postoperative follow-up at 3 months. Conclusions Complete VNs electrode array removal can be safely achieved by using needle tip monopolar electrocautery.

Epidermoid cysts of the pineal region are a rare entity. Herein, the authors describe the endoscopic resection of a recurrent pineal region epidermoid by way of a supracerebellar infratentorial approach. The patient was positioned in the semiseated upright position with head tilted to the right and slightly flexed, maximizing gravity-based cerebellar retraction, and a paramedian craniotomy was performed owing to the gradual flattening of the tentorium from medial to lateral. This setup, in tandem with the enlarged viewing window achieved by use of 0°, 30°, and 70° endoscopes, afforded the necessary access to achieve a satisfactory resection through this anatomical corridor. The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2131.

Background: Controversy continues to exist regarding optimal management of chronic subdural hematoma. We present a different way of using a subdural drain during the post-operative period to assist with drainage. Method: We present a case series of five consecutive patients who underwent subdural hematoma drainage utilizing this technique. Results: Post-operative films revealed good hematoma evacuation, minimal subdural pneumocephalus, and good brain re-expansion. Conclusion: Intraoperative subdural drain irrigation and post-operative distal drain flushing may have beneficial effects on hematoma drainage. Further testing is needed to make definitive conclusions. Keywords: Chronic subdural hematoma, Burr hole craniostomy, Subdural drain placement, Subdural drain irrigation

Given the rapidly evolving pace of research and technology in the neurosurgical field, it is critical to consider the parameters of valid, practical, and meaningful study outcome measures. Here we review fundamental aspects of selecting outcome measures in the context of neurosurgical research. Exemplifying work in meningiomas and high-grade gliomas, we delineate a proposed framework for identifying an appropriate outcome measure. Four fundamental components of an outcome measure are defined and characterized: understanding characteristics of a good outcome measure; developing a research question to address an outcome measure; defining the outcome measure, and considering limitations of an outcome measure. This four-part framework enhances and promotes the methodology for determining if an outcome measure is valid, practical, and ultimately meaningful.

Background: In a split cord malformation (SCM), the spinal cord is divided longitudinally into two distinct hemicords that later rejoin. This can result in a tethered cord syndrome (TCS). Rarely, TCS secondary to SCM presents in adulthood. Here, we present an adult female with Type I SCM resulting in TCS and a review of literature. Case Description: A 57-year-old female with a history of spina bifida occulta presented with a 2-year history of worsening back and left leg pain, difficulty with ambulation, and intermittent urinary incontinence; she had not responded to conservative therapy. Magnetic resonance imaging (MRI) revealed a tethered cord secondary to lumbar type I SCM. The patient underwent an L1–S1 laminectomy for resection of the bony septum with cord detethering. At 2-month follow-up, the patient had improvement in her motor symptoms and less pain. In literature, 25 cases of adult-onset surgically managed SCM with TCS were identified (between 1936 and 2018). Patients averaged 37 years of age at the time of diagnosis, and 56% were female. Conclusion: TCS can present secondary to SCM in adulthood and is characterized predominantly by back and leg pain.

A chart review was performed of 38 children diagnosed with autism spectrum disorder (ASD) by 3 years of age at an inner-city developmental program who subsequently experienced resolution of ASD symptomatology and no longer met diagnostic criteria for ASD at follow-up an average of 4 years later. Demographic, developmental/cognitive data, Childhood Autism Rating Scale, and Autism Diagnostic Observation Schedule data as available were reviewed from the initial diagnostic evaluation and at the time of follow-up. Services received by the children between the time of diagnosis and follow-up, educational setting at the time of follow-up, and emotional/behavioral and learning diagnoses made by the multidisciplinary team at follow-up were reviewed. The findings indicate that residual emotional/behavioral and learning problems were present at follow-up in the vast majority of children in this group and that the majority continued to require educational support.

BACKGROUND Implantation of depth electrodes to localize epileptogenic foci in patients with drug-resistant epilepsy can be accomplished using traditional rigid frame-based, custom frameless, and robotic stereotactic systems. OBJECTIVE To evaluate the accuracy of electrode implantation using the FHC microTargeting platform, a custom frameless platform, without a rigid insertion cannula. METHODS A total of 182 depth electrodes were implanted in 13 consecutive patients who underwent stereoelectroencephalography (SEEG) for drug-resistant epilepsy using the microTargeting platform and depth electrodes without a rigid guide cannula. MATLAB was utilized to evaluate targeting accuracy. Three manual coordinate measurements with high inter-rater reliability were averaged. RESULTS Patients were predominantly male (77%) with average age 35.62 (SD 11.0, range 21-57) and average age of epilepsy onset at 13.4 (SD 7.2, range 3-26). A mean of 14 electrodes were implanted (range 10-18). Mean operative time was 144 min (range 104-176). Implantation of 3 out of 182 electrodes resulted in nonoperative hemorrhage (2 small subdural hematomas and one small subarachnoid hemorrhage). Putative location of onset was identified in all patients. We demonstrated a median lateral target point localization error (LTPLE) of 3.95 mm (IQR 2.18-6.23), a lateral entry point localization error (LEPLE) of 1.98 mm (IQR 1.2-2.85), a target depth error of 1.71 mm (IQR 1.03-2.33), and total target point localization error (TPLE) of 4.95 mm (IQR 2.98-6.85). CONCLUSION Utilization of the FHC microTargeting platform without the use of insertion cannulae is safe, effective, and accurate. Localization of seizure foci was accomplished in all patients and accuracy of depth electrode placement was satisfactory.

There is inadequate neurosurgical literature discussing appropriate clinical study design. Here, we explore considerations for 2 fundamental study designs of epidemiology: experimental and observational cohort studies, through examples of theoretical yet realistic neurosurgical research questions. By examining 2 common neurosurgical procedures-namely, subdural drains for evacuation of chronic subdural hematoma, and the utility of navigation for placing external ventricular drains-we characterize the framework of cohort study models for clinical research applications.

Intracranial collision tumors have rarely been reported in the literature and generally include at least 1 malignant tumor component. Subependymoma with dysembryoplastic neuroepithelial tumor (DNET) is an as-yet unreported combination. Both components are uncommon tumors, and presentation in the foramen of Monro is even more unusual. A 16-year-old male patient with a past medical history significant for asthma presented with a 3-month history of headaches and radiographic evidence of mild obstructive hydrocephalus secondary to a nonenhancing ventricular lesion at the foramen of Monro. He underwent endoscopic biopsy and resection. Pathological analysis revealed distinct components of subependymoma and DNET. At the 1-year follow-up, the patient was doing well without regrowth of tumor. The authors describe a case of intracranial collision tumor demonstrating 2 grade I components: a novel combination of subependymoma and DNET.

Objective Helicopter transport may shorten transportation times for emergent neurosurgical intervention. The usefulness of helicopter transport after spontaneous intraparenchymal hemorrhage is not well studied. This study seeks to clarify factors that are associated with urgent surgical intervention in patients with spontaneous intracerebral hemorrhage following helicopter transport. Methods Records were reviewed for patients with spontaneous intraparenchymal hemorrhage transported by helicopter to Dartmouth-Hitchcock Medical Center between January 2008 and December 2011. Records were evaluated for factors associated with emergent tertiary-level care intervention during the first 24 hours of admission. Results A total of 107 patients met inclusion criteria, with a mean age of 67.2 years. At presentation, 79 (75.24%) were hypertensive, 22 (21.57%) had an increased international normalized ratio, and 47 (45.19%) were intubated. Thirty-three patients (30.8%) underwent 1 or more neurosurgical interventions within 24 hours of arrival, with an additional 6 (5.6%) patients undergoing neurosurgical intervention after 24 hours after admission. On univariate analysis, age, Glasgow Coma Scale (GCS) score, and clot volume were significant predictors of neurosurgical intervention within 24 hours of interfacility helicopter transport. A lobar clot, presence of intraventricular hemorrhage, and presence of >1 cm of midline shift were also associated with neurosurgical intervention within 24 hours. On multivariate analysis, younger age, GCS score of 3–8, and lobar hemorrhage were independent predictors of neurosurgical intervention within 24 hours. Conclusions Two thirds of patients did not undergo any surgical intervention during the first 24 hours of admission after interfacility helicopter transfer. Factors associated with urgent neurosurgical intervention included younger age, low GCS score, and presence of lobar hemorrhage.

Background Epidural abscess (EDA) is an uncommon form of intracranial infection that generally presents with fever, headache, and focal neurologic deficit. Imaging generally reveals a lentiform collection with diffusion restriction on diffusion weighted image. We present an interesting case in which a patient with EDA presented with three weeks of depression with suicidal ideations. The patient displayed no notable infectious signs and the imaging was suggestive of chronic subdural hematoma (SDH) rather than EDA. Case description The patient is a 57-year-old man with past medical history significant for epilepsy and left hemiplegia secondary to remote traumatic brain injury who presented with a three-week history of depression, anxiety, and active suicidal ideation, resulting in psychiatric admission to an outside hospital. He had undergone three previous craniotomies for SDH many years ago and had no significant psychiatric history. Magnetic resonance imaging was consistent with subacute right SDH. On presentation, patient was at neurologic baseline and was afebrile with unremarkable labs. Operative findings demonstrated frank purulence in the epidural space. The patient was treated with antibiotics and both depression and suicidal ideations resolved postoperative day 5. Conclusions EDA can present in atypical ways, especially in patients who have undergone previous cranial procedures. Depression is one possible atypical presentation.

Seizure control is a critical component of care in many neurosurgical conditions. The development of seizures in patients without a previously identified seizure disorder occurs in a significant proportion of traumatic brain injury, subarachnoid hemorrhage, and brain tumor patients. In this literature review and synthesis, we will discuss the incidence of seizures in selected conditions, indications and evidence for the initiation of antiepileptic drugs (AEDs), suggested duration of usage for AEDs, and current AED guidelines by the American Academy of Neurology (AAN), Congress of Neurological Surgeons (CNS), American Academy of Neurological Surgeons (AANS) and international committees.

Coenzyme Q(10) (CoQ(10)) deficiency has been associated with 5 major clinical phenotypes: encephalomyopathy, severe infantile multisystemic disease, nephropathy, cerebellar ataxia, and isolated myopathy. Primary CoQ(10) deficiency is due to defects in CoQ(10) biosynthesis, while secondary forms are due to other causes. A review of 149 cases, including our cohort of 76 patients, confirms that CoQ(10) deficiency is a clinically and genetically heterogeneous syndrome that mainly begins in childhood and predominantly manifests as cerebellar ataxia. Coenzyme Q(10) measurement in muscle is the gold standard for diagnosis. Identification of CoQ(10) deficiency is important because the condition frequently responds to treatment. Causative mutations have been identified in a small proportion of patients.