Pediatric central nervous system (CNS) neuroblastoma: A case report.

Background: Neuroblastomas are rare tumors activated by the FoxR2 gene commonly found in pediatric patients. Due to the novelty of these tumors, there is no standard diagnostic profile. However, they have been found to express Olig2, MAP2, SOX10, ANKRD55, and synaptophysin, and they can be identified with magnetic resonance imaging (MRI). Treatment with chemotherapy combined with stem cell rescue and craniospinal irradiation can improve non-infant patient outcomes. Case Description: We report a case of a 2-year-old patient who was diagnosed with a neuroblastoma through MRI imaging and pathology that confirmed FoxR2 gene activation. The tumor was successfully removed. However, the tumor was not high-grade like most FoxR2 neuroblastomas. Conclusion: The unusual presentation of a low-grade FoxR2 neuroblastoma demonstrates the necessity to conduct further research into the characteristics of these tumors.

Glioblastoma Mimicking Viral Encephalitis Responds to Acyclovir: A Case Series and Literature Review.

Viral encephalitis and glioblastoma are both relatively rare conditions with poor prognoses. While the clinical and radiographic presentations of these diseases are often distinctly different, viral encephalitis can sometimes masquerade as glioblastoma. Rarely, glioblastoma can also be misdiagnosed as viral encephalitis. In some cases where a high-grade glioma was initially diagnosed as viral encephalitis, antiviral administration has proven effective for relieving early symptoms. We present three cases in which patients presented with symptoms and radiographic findings suggestive of viral encephalitis and experienced dramatic clinical improvement following treatment with acyclovir, only to later be diagnosed with glioblastoma in the region of suspected encephalitis and ultimately succumb to tumor progression.

Clinical evaluation and surveillance imaging of children with myelomeningocele and shunted hydrocephalus: a follow-up study.

OBJECTIVEThe majority of children with myelomeningocele undergo implantation of CSF shunts. The efficacy of adding surveillance imaging to clinical evaluation during routine follow-up as a means to minimize the hazard associated with future shunt failure has not been thoroughly studied.METHODSA total of 300 spina bifida clinic visits during the calendar years between 2012 and 2016 were selected for this study (defined as the index clinic visit). Each index visit was preceded by a 6-month period during which no shunt evaluation of any kind was performed. At the index clinic visit, all patients were evaluated by a neurosurgeon. Seventy-four patients underwent previously scheduled surveillance CT or shunt series scans in addition to clinical evaluation (surveillance imaging group), and 226 patients did not undergo surveillance imaging (clinical evaluation group). Subsequent unexpected events, defined as emergency department visits, caregiver-requested clinic visits, and shunt revision surgeries were reviewed. The timing and likelihood of an unexpected event in each of the 2 groups were compared using Cox proportional hazard survival analysis. The rate of shunt revision surgery in the follow-up period as well as the associated outcomes and rate of complications were analyzed.RESULTSThe clinical characteristics of the 2 groups were similar. In the clinical evaluation group, 4 of 226 (1.8%) patients underwent shunt revision based on clinical findings during the index visit, compared to 8 of 74 (10.8%) patients in the surveillance imaging group who underwent shunt revision based on clinical and imaging findings at that visit (p < 0.05). In the subsequent follow-up period, there were 74 unexpected events resulting in 10 shunt revisions in the clinical evaluation group, for an event rate of 33% and operation rate of 13.5%. In the surveillance imaging group there were 23 unexpected events resulting in 2 shunt revisions, for an event rate of 34.8% and an operation rate of 8.7%; neither difference was statistically significant. The complication rate for shunt revision surgery was also not different between the groups.CONCLUSIONSObtaining predecided, routine surveillance imaging in children with myelomeningocele and shunted hydrocephalus resulted in more shunt revisions in asymptomatic patients. For patients who had negative results on surveillance imaging, the rate of shunt revision in the follow-up period was not significantly decreased compared to patients who underwent clinical examination only at the index visit.

The identification of a subgroup of children with traumatic subarachnoid hemorrhage at low risk of neuroworsening.

OBJECTIVEPediatric traumatic subarachnoid hemorrhage (tSAH) often results in intensive care unit (ICU) admission, the performance of additional diagnostic studies, and ICU-level therapeutic interventions to identify and prevent episodes of neuroworsening.METHODSData prospectively collected in an institutionally specific trauma registry between 2006 and 2015 were supplemented with a retrospective chart review of children admitted with isolated traumatic subarachnoid hemorrhage (tSAH) and an admission Glasgow Coma Scale (GCS) score of 13-15. Risk of blunt cerebrovascular injury (BCVI) was calculated using the BCVI clinical prediction score.RESULTSThree hundred seventeen of 10,395 pediatric trauma patients were admitted with tSAH. Of the 317 patients with tSAH, 51 children (16%, 23 female, 28 male) were identified with isolated tSAH without midline shift on neuroimaging and a GCS score of 13-15 at presentation. The median patient age was 4 years (range 18 days to 15 years). Seven had modified Fisher grade 3 tSAH; the remainder had grade 1 tSAH. Twenty-six patients (51%) had associated skull fractures; 4 involved the petrous temporal bone and 1 the carotid canal. Thirty-nine (76.5%) were admitted to the ICU and 12 (23.5%) to the surgical ward. Four had an elevated BCVI score. Eight underwent CT angiography; no vascular injuries were identified. Nine patients received an imaging-associated general anesthetic. Five received hypertonic saline in the ICU. Patients with a modified Fisher grade 1 tSAH had a significantly shorter ICU stay as compared to modified Fisher grade 3 tSAH (1.1 vs 2.5 days, p = 0.029). Neuroworsening was not observed in any child.CONCLUSIONSChildren with isolated tSAH without midline shift and a GCS score of 13-15 at presentation appear to have minimal risk of neuroworsening despite the findings in some children of skull fractures, elevated modified Fisher grade, and elevated BCVI score. In this subgroup of children with tSAH, routine ICU-level care and additional diagnostic imaging may not be necessary for all patients. Children with modified Fisher grade 1 tSAH may be particularly unlikely to require ICU-level admission. Benefits to identifying a subgroup of children at low risk of neuroworsening include improvement in healthcare efficiency as well as decreased utilization of unnecessary and potentially morbid interventions, including exposure to ionizing radiation and general anesthesia.

A First-in-Human, Phase I Study of Neural Stem Cell Transplantation for Chronic Spinal Cord Injury.

We tested the feasibility and safety of human-spinal-cord-derived neural stem cell (NSI-566) transplantation for the treatment of chronic spinal cord injury (SCI). In this clinical trial, four subjects with T2-T12 SCI received treatment consisting of removal of spinal instrumentation, laminectomy, and durotomy, followed by six midline bilateral stereotactic injections of NSI-566 cells. All subjects tolerated the procedure well and there have been no serious adverse events to date (18-27 months post-grafting). In two subjects, one to two levels of neurological improvement were detected using ISNCSCI motor and sensory scores. Our results support the safety of NSI-566 transplantation into the SCI site and early signs of potential efficacy in three of the subjects warrant further exploration of NSI-566 cells in dose escalation studies. Despite these encouraging secondary data, we emphasize that this safety trial lacks statistical power or a control group needed to evaluate functional changes resulting from cell grafting.

Interaction Between the Contributions of Tumor Location, Tumor Grade, and Patient Age to the Survival Benefit Associated with Gross Total Resection.

BACKGROUND: Gross total resection (GTR) in patients with glioblastoma (GB) and anaplastic astrocytoma (AA) is associated with improved survival. We examined how tumor location, tumor grade, and age affected this benefit. METHODS: We selected patients with lobar AA or GB in the Surveillance, Epidemiology, and End Results database from 1999 to 2010. Survival analyses were performed using Kaplan-Meier curves and Cox proportional hazards models. RESULTS: We identified and studied 1429 patients with lobar AA and 12,537 patients with lobar GB in the Surveillance, Epidemiology, and End Results database. In multivariate Cox proportional hazards analysis, GTR of frontal lobe AA was associated with approximately 50% reduction in risk of death compared with subtotal resection (STR) (hazard ratio 0.51; 95% confidence interval, 0.36-0.73; P < 0.001). This hazard ratio corresponds to a median increase in overall survival of >8 years with GTR compared with STR. In nonfrontal AAs, there was no survival difference between GTR and STR (hazard ratio 0.79; 95% confidence interval, 0.58-1.08; P = 0.143). Location-specific survival benefit from GTR in AAs was significant in patients ≤50 years old but was not evident in patients >50 years old. In patients with GB, no location-dependent survival benefit with GTR was observed. CONCLUSIONS: Our results demonstrate complex interaction between tumor grade, frontal lobe location, and age in their various contributions to survival benefit gained from GTR. The greatest survival benefit of GTR relative to STR was observed in patients ≤50 years old with frontal AAs.

Impact of neurosurgeon specialization on patient outcomes for intracranial and spinal surgery: a retrospective analysis of the Nationwide Inpatient Sample 1998-2009.

OBJECTIVE The subspecialization of neurosurgical practice is an ongoing trend in modern neurosurgery. However, it remains unclear whether the degree of surgeon specialization is associated with improved patient outcomes. The authors hypothesized that a trend toward increased neurosurgeon specialization was associated with improved patient morbidity and mortality rates. METHODS The Nationwide Inpatient Sample (NIS) was used (1998-2009). Patients were included in a spinal analysis cohort for instrumented spine surgery involving the cervical spine ( International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes 81.31-81.33, 81.01-81.03, 84.61-84.62, and 84.66) or lumbar spine (codes 81.04-81.08, 81.34-81.38, 84.64-84.65, and 84.68). A cranial analysis cohort consisted of patients receiving a parenchymal excision or lobectomy operation (codes 01.53 and 01.59). Surgeon specialization was measured using unique surgeon identifiers in the NIS and defined as the proportion of a surgeon's total practice dedicated to cranial or spinal cases. RESULTS A total of 46,029 and 231,875 patients were identified in the cranial and spinal analysis cohorts, respectively. On multivariate analysis in the cranial analysis cohort (after controlling for overall surgeon volume, patient demographic data/comorbidities, hospital characteristics, and admitting source), each percentage-point increase in a surgeon's cranial specialization (that is, the proportion of cranial cases) was associated with a 0.0060 reduction in the log odds of patient mortality (95% CI 0.0034-0.0086) and a 0.0042 reduction in the log odds of morbidity (95% CI 0.0032-0.0052). This resulted in a 15% difference in the predicted probability of mortality for neurosurgeons at the 75th versus the 25th percentile of cranial specialization. In the spinal analysis cohort, each percentage-point increase in a surgeon's spinal specialization was associated with a 0.0122 reduction in the log odds of mortality (95% CI 0.0074-0.0170) and a 0.0058 reduction in the log odds of morbidity (95% CI 0.0049-0.0067). This resulted in a 26.8% difference in the predicted probability of mortality for neurosurgeons at the 75th versus the 25th percentile of spinal specialization. CONCLUSIONS For both spinal and cranial surgery patient cohorts derived from the NIS database, increased surgeon specialization was significantly and independently associated with improved mortality and morbidity rates, even after controlling for overall case volume.

ICP management in patients suffering from traumatic brain injury: a systematic review of randomized controlled trials.

BACKGROUND: Severe traumatic brain injury (sTBI) is a major cause of morbidity and mortality. Intracranial pressure (ICP) monitoring and management form the cornerstone of treatment paradigms for sTBI in developed countries. We examine the available randomized controlled trial (RCT) data on the impact of ICP management on clinical outcomes after sTBI. METHODS: A systematic review of the literature on ICP management following sTBI was performed to identify pertinent RCT articles. RESULTS: We identified six RCT articles that examined whether ICP monitoring, decompressive craniectomy, or barbiturate coma improved clinical outcomes after sTBI. These studies support (1) the utility of ICP monitoring in the management of sTBI patients and (2) craniectomy and barbiturate coma as effective methods for the management of intracranial hypertension secondary to sTBI. However, despite adequate ICP control in sTBI patients, a significant proportion of surviving patients remain severely disabled. CONCLUSIONS: If one sets the bar at the level of functional independence, then the RCT data raises questions pertaining to the utility of decompressive craniectomy and barbiturate coma in the setting of sTBI.

Subpial Adeno-associated Virus 9 (AAV9) Vector Delivery in Adult Mice.

The successful development of a subpial adeno-associated virus 9 (AAV9) vector delivery technique in adult rats and pigs has been reported on previously. Using subpially-placed polyethylene catheters (PE-10 or PE-5) for AAV9 delivery, potent transgene expression through the spinal parenchyma (white and gray matter) in subpially-injected spinal segments has been demonstrated. Because of the wide range of transgenic mouse models of neurodegenerative diseases, there is a strong desire for the development of a potent central nervous system (CNS)-targeted vector delivery technique in adult mice. Accordingly, the present study describes the development of a spinal subpial vector delivery device and technique to permit safe and effective spinal AAV9 delivery in adult C57BL/6J mice. In spinally immobilized and anesthetized mice, the pia mater (cervical 1 and lumbar 1-2 spinal segmental level) was incised with a sharp 34 G needle using an XYZ manipulator. A second XYZ manipulator was then used to advance a blunt 36G needle into the lumbar and/or cervical subpial space. The AAV9 vector (3-5 µL; 1.2 x 1013 genome copies (gc)) encoding green fluorescent protein (GFP) was then injected subpially. After injections, neurological function (motor and sensory) was assessed periodically, and animals were perfusion-fixed 14 days after AAV9 delivery with 4% paraformaldehyde. Analysis of horizontal or transverse spinal cord sections showed transgene expression throughout the entire spinal cord, in both gray and white matter. In addition, intense retrogradely-mediated GFP expression was seen in the descending motor axons and neurons in the motor cortex, nucleus ruber, and formatio reticularis. No neurological dysfunction was noted in any animals. These data show that the subpial vector delivery technique can successfully be used in adult mice, without causing procedure-related spinal cord injury, and is associated with highly potent transgene expression throughout the spinal neuraxis.

Clarification of Eponymous Anatomical Terminology: Structures Named After Dr Geoffrey V. Osborne That Compress the Ulnar Nerve at the Elbow.

BACKGROUND: In 1957, Dr Geoffrey Osborne described a structure between the medial epicondyle and the olecranon that placed excessive pressure on the ulnar nerve. Three terms associated with such structures have emerged: Osborne's band, Osborne's ligament, and Osborne's fascia. As anatomical language moves away from eponymous terminology for descriptive, consistent nomenclature, we find discrepancies in the use of anatomic terms. This review clarifies the definitions of the above 3 terms. METHODS: We conducted an extensive electronic search via PubMed and Google Scholar to identify key anatomical and surgical texts that describe ulnar nerve compression at the elbow. We searched the following terms separately and in combination: "Osborne's band," "Osborne's ligament," and "Osborne's fascia." A total of 36 papers were included from 1957 to 2016. RESULTS: Osborne's band, Osborne's ligament, and Osborne's fascia were found to inconsistently describe the etiology of ulnar neuritis, referring either to the connective tissue between the 2 heads of the flexor carpi ulnaris muscle as described by Dr Osborne or to the anatomically distinct fibrous tissue between the olecranon process of the ulna and the medial epicondyle of the humerus. CONCLUSIONS: The use of eponymous terms to describe ulnar pathology of the elbow remains common, and although these terms allude to the rich history of surgical anatomy, these nonspecific descriptions lead to inconsistencies. As Osborne's band, Osborne's ligament, and Osborne's fascia are not used consistently across the literature, this research demonstrates the need for improved terminology to provide reliable interpretation of these terms among surgeons.

Perioperative Vision Loss in Cervical Spinal Surgery.

STUDY DESIGN: Retrospective multicenter case series. OBJECTIVE: To assess the rate of perioperative vision loss following cervical spinal surgery. METHODS: Medical records for 17 625 patients from 21 high-volume surgical centers from the AOSpine North America Clinical Research Network who received cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, inclusive, were reviewed to identify occurrences of vision loss following surgery. RESULTS: Of the 17 625 patients in the registry, there were 13 946 patients assessed for the complication of blindness. There were 9591 cases that involved only anterior surgical approaches; the remaining 4355 cases were posterior and/or circumferential fusions. There were no cases of blindness or vision loss in the postoperative period reported during the sampling period. CONCLUSIONS: Perioperative vision loss following cervical spinal surgery is exceedingly rare.

Relationship of the lumbar plexus branches to the lumbar spine: anatomical study with application to lateral approaches.

BACKGROUND CONTEXT: Injuries to the lumbar plexus during lateral approaches to the spine are not uncommon and may result in permanent deficits. However, the literature contains few studies that provide landmarks for avoiding the branches of the lumbar plexus. PURPOSE: The present anatomical study was performed to elucidate the course of these nerves in relation to lateral approaches to the lumbar spine. STUDY DESIGN: This is a quantitative anatomical cadaveric study. METHODS: The lumbar plexus and its branches were dissected on 12 cadaveric sides. Metal wires were laid on the nerves along their paths on the posterior abdominal wall. Fluoroscopy was performed in the anteroposterior and lateral positions. The relationships between regional bony landmarks and the branches of the lumbar plexus were observed. RESULTS: When viewed laterally, the greatest concentration of nerves occurred from the posteroinferior aspect of L4, inferior along the posterior one-third of the body of L5, then at the level of the sacral promontory. On the basis of our study, approaches to the anterior two-thirds of the L4 vertebra and anterior third of L5 will result in the lowest chance of lumbar plexus nerve injury. In addition, lateral muscle dissection through the psoas major should be in a superior to inferior direction in order to minimize nerve injury. Laterally, the widest corridor between branches in the abdominal wall was between the subcostal and iliohypogastric nerves. CONCLUSIONS: The findings of our cadaveric study provide surgeons who approach the lateral lumbar spine with data that could decrease injuries to the branches of the lumbar plexus, thus lessening patient morbidity.

Low-profile Visualized Intraluminal Support Junior Device for the Treatment of Intracranial Aneurysms.

OBJECTIVE: Early case series suggest that the recently introduced Low-profile Visualized Intraluminal Support Junior (LVIS Jr.) device (MicroVention-Terumo, Inc., Tustin, CA) may be used to treat wide-necked aneurysms that would otherwise require treatment with intrasaccular devices or open surgery. We report our single-center experience utilizing LVIS Jr. to treat intracranial aneurysms involving 1.8-2.5 mm parent arteries. METHODS: We retrospectively reviewed records of patients treated with the LVIS Jr. device for intracranial aneurysms at a single center. A total of 21 aneurysms were treated in 18 patients. Aneurysms were 2-25 mm in diameter; one was ruptured, while three had recurred after previous rupture and treatment. Lesions were distributed across the anterior (n=12) and posterior (n=9) circulations. Three were fusiform morphology. RESULTS: Stent deployment was successful in 100% of cases with no immediate complications. Seventeen aneurysms were treated with stent-assisted coil embolization resulting in immediate complete occlusion in 94% of cases. Two fusiform aneurysms arising from the posterior circulation were further treated with elective clip ligation after delayed expansion and recurrence; no lesions required further endovascular treatment. Four aneurysms were treated by flow diversion with stand-alone LVIS Jr. stent, and complete occlusion was achieved in three cases. Small foci of delayed ischemic injury were noted in two patients in the setting of antiplatelet medication noncompliance. No in-stent stenosis, migration, hemorrhage, or permanent deficits were observed. Good functional outcome based on the modified Rankin Scale score (mRS ≤ 2) was achieved in 100% of cases. CONCLUSION: Our midterm results suggest that the LVIS Jr. stent may be used for a variety of intracranial aneurysms involving small parent arteries (1.8-2.5 mm) with complete angiographic occlusion, parent vessel preservation, and functional clinical outcomes. This off-label expansion would increase the number of aneurysms amenable to endovascular treatment. Future studies may build upon our experiences with flow diversion and treatment of complex or multiple lesions.

Lateral mass screw stimulation thresholds in posterior cervical instrumentation surgery: a predictor of medial deviation.

OBJECTIVE Normative data exists for stimulus-evoked pedicle screw electromyography (EMG) current thresholds in the lumbar spine, and is routinely referenced during spine surgeries to detect a screw breach, prevent injury of neural elements, and ensure the most biomechanically sound instrumentation construct. To date, similar normative data for cervical lateral mass screws is limited, thus the utility of lateral mass screw testing remains unclear. To address this disparity, in this study the authors describe cumulative lateral mass screw stimulation threshold data in patients undergoing posterior cervical instrumentation with lateral mass screws. These data are correlated with screw placement on postoperative imaging, and a novel correlation is discovered with direct clinical implications. METHODS Using a ball-tip probe, 154 lateral mass screws in 21 patients were electrically tested intraoperatively. In each case, for each screw, the lowest (or threshold) current at which the first polyphasic stimulus-evoked EMG response was reproducibly observed by a neurophysiologist was recorded. All patients underwent postoperative CT. Screw position within the lateral mass was first measured in the axial and sagittal planes for each lateral mass screw using the CT images. Screw placement was also evaluated by 2 independent physicians, blinded to current threshold data, on a binary scale of acceptability. The predictive capacity of screw EMG threshold data was evaluated via multivariable regression analyses and receiver operating characteristic (ROC) analyses. Predictive capacity was examined with respect to screw position within the lateral mass, as well as screw acceptability. RESULTS Lateral mass screw EMG thresholds did not appear to differ significantly for screws considered "acceptable" versus "unacceptable" according to the radiographic criteria. Accordingly, ROC analysis confirmed that EMG current threshold data were of minimal utility in predicting screw radiographic acceptability. However, EMG threshold was significantly predictive of screw medial distance from the spinal canal. A screw stimulating below 7.5 mA correctly identified a screw as being within 2 mm of the spinal canal with 75% sensitivity and 92% specificity (positive predictive value 20%, negative predictive value 99.3%), independent of its distance relative to other lateral mass landmarks. EMG current threshold was not significantly predictive of screw deviation in the superior or inferior directions, and was inversely predictive of screw deviations in the lateral direction. CONCLUSIONS In the context of uncertainty regarding the utility of cervical lateral mass EMG current threshold data, this study found that EMG current thresholds correspond significantly, and exclusively, with screw distance from the spinal canal. This association appears independent of other criteria for screw misplacement. As such, the authors recommend that EMG current thresholds be referenced in the case of a suspected medial breach as an effective means to rule out screw placement too medial to the spinal canal.

Unusual and Rare Locations for Craniopharyngiomas: Clinical Significance and Review of the Literature.

OBJECTIVE: This study discusses rare and unusual locations of primary craniopharyngiomas. METHODS: We describe a case of a craniopharyngioma in the cerebellopontine angle. As a result of this unusual location, we performed a literature review of the ectopic occurrence of craniopharyngiomas using Pubmed, Cochrane Database, Trip, and Google Scholar to search for the terms "unusual," "uncommon," and "ectopic" in combination with "craniopharyngioma." The bibliographies of relevant articles were also searched. RESULTS: We found 28 reported cases of rare anatomic locations for primary craniopharyngiomas. The average age of the patients was 30.8 years. Several patients had Gardner syndrome. CONCLUSIONS: Craniopharyngiomas are most often located in the suprasellar region. Presentation in sites outside the parasellar region is rare. Among these ectopic sites, the cerebellopontine angle appears to be the most common location.

A Review of Stem Cell Therapy for Spinal Cord Injury: Large Animal Models and the Frontier in Humans.

OBJECTIVE: To review the literature of spinal cord injury and stem cell therapy for large animal models and incorporate those results into an understanding of stem cell therapy for human cord injury. METHODS: Review of the literature. RESULTS: Eleven canine studies were identified and 3 sub-human primate studies were identified showing variable results. CONCLUSIONS: Stem cell therapy is a promising therapeutic option for patients with spinal cord injury; however, the technology has many un-answered questions and further research is needed.

The Inter-Mammary Sticky Roll: A Novel Technique for Securing a Doppler Ultrasonic Probe to the Precordium for Venous Air Embolism Detection.

Venous air embolism is a devastating and potentially life-threatening complication that can occur during neurosurgical procedures. We report the development and use of the "inter-mammary sticky roll," a technique to reliably secure a precordial Doppler ultrasonic probe to the chest wall during neurosurgical cases that require lateral decubitus positioning. We have found that this noninvasive technique is safe, and effectively facilitates a constant Doppler signal with no additional risk to the patient.

Novel Transabdominal Motor Action Potential (TaMAP) Neuromonitoring System for Spinal Surgery.

INTRODUCTION: Minimally invasive lateral lumbar interbody fusion (LLIF) approaches to the lumbar spine reduce patient morbidity compared to anterior or posterior alternatives. This approach, however, decreases direct anatomical visualization, creating the need for highly sensitive and specific neurophysiological monitoring. We seek to determine feasibility in 'transabdominal motor action potential (TaMAP)' monitoring as an assessment for the integrity of the neural elements during lateral-approach surgeries to the lumbar spine. METHODS: Cathode and anode leads were placed on the posterior and anterior surfaces of two porcine subjects. Currents of varying degrees were transmitted across, from front to back. Motor responses were monitored and recorded by needle electrodes in specific distal muscle groups of the lower extremity. Lastly, the cathode and anode were placed anterior and posterior to the chest wall and stimulated to the maximum of 1500 mA to determine any effect on cardiac rhythm. RESULTS: Responses were seen by measuring vertical height differences between peaks of corresponding evoked potentials. Recruitment began at 200 mA in the lower extremities. Stimulation at 450 mA recruited a reliable and distinguishable electrographic response from most muscle groups. Responses were recorded and reliably measured and increased in proportion to the graduation of transabdominal stimulation current; no responses were seen in the arms or face. 1500 mA across the chest wall failed to stimulate or induce cardiac arrhythmia on repeated stimulation, indicating safety of stimulation. CONCLUSION: TaMAPs seen in the animal model provide a potential alternative to standard transcranial motor evoked potentials done in the lateral approach of LLIFs. TaMAP recordings in most muscle groups were recordable and reliable, though some muscle groups failed to stimulate. Safety of transabdominal motor evoked potentials was confirmed in this porcine study. Future studies should examine TaMAPs reliability in detecting compressive lesions of nerve roots and peripheral nerves.

Potent spinal parenchymal AAV9-mediated gene delivery by subpial injection in adult rats and pigs.

Effective in vivo use of adeno-associated virus (AAV)-based vectors to achieve gene-specific silencing or upregulation in the central nervous system has been limited by the inability to provide more than limited deep parenchymal expression in adult animals using delivery routes with the most clinical relevance (intravenous or intrathecal). Here, we demonstrate that the spinal pia membrane represents the primary barrier limiting effective AAV9 penetration into the spinal parenchyma after intrathecal AAV9 delivery. We develop a novel subpial AAV9 delivery technique and AAV9-dextran formulation. We use these in adult rats and pigs to show (i) potent spinal parenchymal transgene expression in white and gray matter including neurons, glial and endothelial cells after single bolus subpial AAV9 delivery; (ii) delivery to almost all apparent descending motor axons throughout the length of the spinal cord after cervical or thoracic subpial AAV9 injection; (iii) potent retrograde transgene expression in brain motor centers (motor cortex and brain stem); and (iv) the relative safety of this approach by defining normal neurological function for up to 6 months after AAV9 delivery. Thus, subpial delivery of AAV9 enables gene-based therapies with a wide range of potential experimental and clinical utilizations in adult animals and human patients.

Intracranial Rhabdomyoma: Case Report and Review of the Literature.

A 24-year-old male presented with eight months of increasingly severe frontal headaches, decreased right facial sensation, and periodic vertigo. Magnetic resonance imaging demonstrated a heterogeneously contrast-enhancing mass involving and expanding the right foramen ovale.  A biopsy of the lesion was performed, and the final pathologic diagnosis revealed a neoplastic rhabdomyoma. To date, only five cases of intracranial rhabdomyoma have been reported, and a rhabdomyoma involving the trigeminal nerve has never been described in an adult. This manuscript reviews the available literature and highlights the clinical, imaging, pathologic characteristics, and surgical management of these exceedingly rare lesions.