G. Carl Huber (1865-1934): A Michigan Pioneer in Peripheral Nerve Injury and Regeneration

The treatment of peripheral nerve injuries has seen tremendous innovations over the past century. Dr Gotthelf Carl Huber, an American immigrant and early experimental pioneer in the field of peripheral nerve injury, created a foundation of scientific knowledge for these advancements. At the beginning of his career, Huber published novel work in peripheral nerve injury, supporting the concept of Wallerian degeneration and demonstrating the use of nerve grafting for repair. As his scientific career evolved into other research areas at the University of Michigan, Huber's impact extended far beyond just the study of peripheral nerve injury. Because of the external forces of the First World War, Dr Huber's focus returned to translational projects concentrated on the treatment of neuromas and war time peripheral nerve injuries. Huber's scientific impact in the field of peripheral nerve injury and repair came as a result of his incredible work ethic, mentorship, and tremendous leadership qualities; through this, his work still influences clinical practice today, a century later.

Answering Our Nation's Call: A Solution for Military Neurosurgery Wartime Readiness Through Civilian Collaboration

Military-civilian partnerships have built the foundation for US neurosurgery as we see it today. Each conflict throughout history has led to expansion within the field of neurosurgery, benefiting civilian patients and those in uniform. Despite the field's growth during wartime, military neurosurgical case volume declines during peacetime, and as a result, important knowledge gained is at risk of being lost. The current landscape of military neurosurgery reflects the relative peacetime for the US-World relationship. Because of this peacetime, the surgical case volume and experience of the military neurosurgeon are declining rapidly. In addition to providing a history of military-civilian partnerships in neurosurgery, we have analyzed the declining case volume trends at a single military treatment facility with neurosurgical capabilities. We compared the case volume of a military neurosurgeon at a civilian partnered location with their previous volume at a military treatment facility and analyzed current trends in wartime readiness by Neurosurgery Knowledge, Skills and Abilities metrics. We believe that military civilian partnerships hold the key to scaffolding the experience to maintain the wartime readiness in the military neurosurgical community.

A history of neurosurgical capabilities in the United States Pacific Command: from World War II to present

Neurosurgery has benefited from innovations as a result of military conflict. The volume and complexity of injuries sustained on the battlefield require medical teams to triage, innovate, and practice beyond their capabilities in order to treat wartime injuries. The neurosurgeons who practiced in the Pacific Command (PACOM) during World War II, the Korean War, and the War in Vietnam built upon field operating room knowledge and influenced the logistics of treating battle-injured patients in far-forward environments. Modern-day battles are held on new terrain, and the military neurosurgeon must adapt. War in the PACOM uniquely presented significant obstacles due to geographic isolation, ultimately accelerating the growth and adaptability of military neurosurgery and medical evacuation. The advancements in infrastructure and resource mobilization made during PACOM conflicts continue to inform modern-day practices and provide insight for future conflicts. In this historical article, the authors review the development and evolution of neurosurgical care, forward surgical teams, and mobile field hospitals with surgical capabilities through US conflicts in the PACOM.

Neonatal infratentorial subdural hematoma contributing to obstructive hydrocephalus in the setting of therapeutic cooling: A case report

BACKGROUND

Symptomatic neonatal subdural hematomas usually result from head trauma incurred during vaginal delivery, most commonly during instrument assistance. Symptomatic subdural hematomas are rare in C-section deliveries that were not preceded by assisted delivery techniques. Although the literature is inconclusive, another possible cause of subdural hematomas is therapeutic hypothermia.

CASE SUMMARY

We present a case of a term neonate who underwent therapeutic whole-body cooling for hypoxic ischemic encephalopathy following an emergent C-section delivery for prolonged decelerations. Head ultrasound on day of life 3 demonstrated a rounded mass in the posterior fossa. A follow-up brain magnetic resonance imaging confirmed hypoxic ischemic encephalopathy and clarified the subdural hematomas in the posterior fossa causing mass effect and obstructive hydrocephalus.

CONCLUSION

The aim of this report is to highlight the rarity and importance of mass-like subdural hematomas causing obstructive hydrocephalus, particularly in the setting of hypoxic ischemic encephalopathy and therapeutic whole-body cooling.

The utility of routine post-hospitalization CT imaging in patients with non-operative mild to moderate traumatic brain injury

Primary Objective: The purpose of this study was to determine the utility of CT imaging in patients with non-operative mild-moderate TBI with respect to changes in management.Methods: We conducted a retrospective analysis for 191 patients over a 5-year interval to examine whether follow-up CT initiated a change in management. We created a logistic regression model to incorporate different variables contributing to change in management.Results: Of 191 patients, 31 (16.2%) underwent a change in management. Change in management was associated with older age (65 yo vs. 55 yo, p = .011), diagnosis of subdural hematoma (p = .041), antiplatelet/anticoagulant therapy (p = .009), imaging performed (p = .16), and increased blood products on CT (p = <0.0001). For patients on antiplatelet/anticoagulant therapy, only those with worsening findings on CT required a change in management (p = .0002, 0.039). Surgical intervention was indicated in two patients.Conclusions: Limited clinical value exists in repeat CT scans for patients with mild TBI. Most patients with traumatic SAH, contusions, or asymptomatic patients should not have repeat imaging, as our study revealed only 2% of patients with positive CT finding and 0.6% requiring surgical intervention.

Direct enhancement of readiness for wartime critical specialties by civilian-military partnerships for neurosurgical care: residency training and beyond

Military neurosurgery has played an integral role in the development and innovation of neurosurgery and neurocritical care in treating battlefield injuries. It is of paramount importance to continue to train and prepare the next generation of military neurosurgeons. For the Army, this is currently primarily achieved through the military neurosurgery residency at the National Capital Consortium and through full-time out-service positions at the Veterans Affairs-Department of Defense partnerships with the University of Florida, the University of Texas-San Antonio, and Baylor University. The authors describe the application process for military neurosurgery residency and highlight the training imparted to residents in a busy academic and level I trauma center at the University of Florida, with a focus on how case variety and volume at this particular civilian-partnered institution produces neurosurgeons who are prepared for the complexities of the battlefield. Further emphasis is also placed on collaboration for research as well as continuing education to maintain the skills of nondeployed neurosurgeons. With ongoing uncertainty regarding future conflict, it is critical to preserve and expand these civilian-military partnerships to maintain a standard level of readiness in order to face the unknown with the confidence befitting a military neurosurgeon.

MRI-guided laser interstitial thermal therapy in an infant with tuberous sclerosis: technical case report

Cortical tubers associated with tuberous sclerosis complex (TSC) are potential epileptic foci that are often amenable to resective or ablative surgeries, and controlling seizures at a younger age may lead to improved functional outcomes. MRI-guided laser interstitial thermal therapy (MRgLITT) has become a popular minimally invasive alternative to traditional craniotomy. Benefits of MRgLITT include the ability to monitor the ablation in real time, a smaller incision, shorter hospital stay, reduced blood loss, and reduced postoperative pain. To place the laser probe for LITT, however, stereotaxy is required-which classically involves head fixation with cranial pins. This creates a relative minimum age limit of 2 years old because it demands a mature skull and fused cranial sutures. A novel technique is presented for the application of MRgLITT in a 6-month-old infant for the treatment of epilepsy associated with TSC. To the authors' knowledge this is the youngest patient treated with laser ablation. The authors used a frameless navigation technique with a miniframe tripod system and intraoperative reference points. This technique expands the application of MRgLITT to younger patients, which may lead to safer surgical interventions and improved outcomes for these children.

Shunt freedom and clinical resolution of idiopathic intracranial hypertension after bariatric surgery in the pediatric population: report of 3 cases

Idiopathic intracranial hypertension (IIH), formerly known as pseudotumor cerebri, is a disease of elevated intracranial pressure that is thought to develop due to impaired CSF absorption related to elevated venous sinus pressure in the setting of increased intraabdominal and thoracic pressures. Symptoms can be disabling and, if left untreated, can lead to permanent visual loss. Previous treatments directed toward vision preservation include CSF diversion through shunting and optic nerve sheath fenestration. Recently, attention has been turned toward surgical weight loss strategies as an alternative to shunt treatment. The authors present a report of 3 patients with adolescent-onset IIH that was treated at the authors' institution (Duke University) in whom bariatric surgery was pursued successfully. The patients had previously undergone CSF shunting at ages 12, 15, and 23 years. They were shunt dependent for a collective average of 3.3 years prior to bariatriwc surgery. All patients reported "low-pressure" or postural headaches after bariatric surgery that correlated with dramatic reduction in their weight. Two of the 3 patients had their shunts removed and continued to be shunt free 1.5 years later at last follow-up; the third patient remained shunt dependent with the pressure set at 200 mm H₂O. Given the significant complications inherent to multiple shunt revisions, earlier intervention for weight loss, including bariatric surgery, in these patients might have prevented complications and the associated health care burden. The authors recommend a multidisciplinary approach for IIH treatment with early consideration for weight loss interventions in select patients.

Characterization of Gene Expression Phenotype in Amyotrophic Lateral Sclerosis Monocytes

Importance

Amyotrophic lateral sclerosis (ALS) is a common adult-onset neurodegenerative disease characterized by selective loss of upper and lower motor neurons. Patients with ALS have persistent peripheral and central inflammatory responses including abnormally functioning T cells and activated microglia. However, much less is known about the inflammatory gene profile of circulating innate immune monocytes in these patients.

Objective

To characterize the transcriptomics of peripheral monocytes in patients with ALS.

Design, Setting, and Participants

Monocytes were isolated from peripheral blood of 43 patients with ALS and 22 healthy control individuals. Total RNA was extracted from the monocytes and subjected to deep RNA sequencing, and these results were validated by quantitative reverse transcription polymerase chain reaction.

Main Outcomes and Measures

The differential expressed gene signatures of these monocytes were identified using unbiased RNA sequencing strategy for gene expression profiling.

Results

The demographics between the patients with ALS (mean [SD] age, 58.8 [1.57] years; 55.8% were men and 44.2% were women; 90.7% were white, 4.65% were Hispanic, 2.33% were black, and 2.33% were Asian) and control individuals were similar (mean [SD] age, 57.6 [2.15] years; 50.0% were men and 50.0% were women; 90.9% were white, none were Hispanic, none were black, and 9.09% were Asian). RNA sequencing data from negative selected monocytes revealed 233 differential expressed genes in ALS monocytes compared with healthy control monocytes. Notably, ALS monocytes demonstrated a unique inflammation-related gene expression profile, the most prominent of which, including IL1B, IL8, FOSB, CXCL1, and CXCL2, were confirmed by quantitative reverse transcription polymerase chain reaction (IL8, mean [SE], 1.00 [0.18]; P = .002; FOSB, 1.00 [0.21]; P = .009; CXCL1, 1.00 [0.14]; P = .002; and CXCL2, 1.00 [0.11]; P = .01). Amyotrophic lateral sclerosis monocytes from rapidly progressing patients had more proinflammatory DEGs than monocytes from slowly progressing patients.

Conclusions and Relevance

Our data indicate that ALS monocytes are skewed toward a proinflammatory state in the peripheral circulation and may play a role in ALS disease progression, especially in rapidly progressing patients. This increased inflammatory response of peripheral immune cells may provide a potential target for disease-modifying therapy in patients with ALS.

External ventricular drain practice variations: results from a nationwide survey

OBJECTIVE While guidelines exist for many neurosurgical procedures, external ventricular drain (EVD) insertion has yet to be standardized. The goal of this study was to survey the neurosurgical community and determine the most frequent EVD insertion practices. The hypothesis was that there would be no standard practices identified for EVD insertion or methods to avoid EVD-associated infections. METHODS The American Association of Neurological Surgeons membership database was queried for all eligible neurosurgeons. A 16-question, multiple-choice format survey was created and sent to 7217 recipients. The responses were collected electronically, and the descriptive results were tabulated. Data were analyzed using the chi-square test. RESULTS In total, 1143 respondents (15.8%) completed the survey, and 705 respondents (61.6%) reported tracking EVD infections at their institution. The most common self-reported infection rate ranged from 1% to 3% (56.1% of participants), and 19.7% of respondents reported a 0% infection rate. In total, 451 respondents (42.7%) indicated that their institution utilizes a formal protocol for EVD placement. If a respondent's institution had a protocol, only 258 respondents (36.1%) always complied with the protocol. Protocol utilization for EVD insertion was significantly more frequent among residents, in academic/hybrid centers, in ICU settings, and if the institution tracked EVD-associated infection rates (p < 0.05). A self-reported 0% infection rate was significantly more commonly associated with a higher level of training (e.g., attending physicians), private center settings, a clinician performing 6 to 10 EVD insertions within the previous 12 months, and prophylactic continuous antibiotic utilization (p < 0.05). CONCLUSIONS This survey demonstrated heterogeneity in the practices for EVD insertion. No standard practices have been proposed or adopted by the neurosurgical community for EVD insertion or complication avoidance. These results highlight the need for the nationwide standardization of technique and complication prevention measures.

Bilateral internal auditory canal gangliogliomas mimicking neurofibromatosis Type II

Background:

Gangliogliomas are rare low grade, typically well-differentiated, tumors that are composed of mature ganglion cells and neoplastic glial cells. These tumors can appear at virtually any location along the neuroaxis but classically occur in the temporal lobe of young patients. In a small number of cases, gangliogliomas have presented as masses in the brainstem or involving cranial nerves. With the exception of vestibular schwannomas, bilateral tumors in the region of the internal auditory canal (IAC) or cerebellopontine angle (CPA) are exceedingly rare.

Case Description:

We report a case of a 58-year-old male who presented with hearing loss, tinnitus, and vertigo. Initial magnetic resonance imaging revealed bilateral nonenhancing IAC/CPA tumors. Based on this finding, a presumptive diagnosis of neurofibromatosis Type II was made, which was initially managed conservatively with close observation. He returned for follow-up with worsening vertigo and tinnitus, thus prompting the decision to proceed with surgical resection of the symptomatic mass. Intriguingly, pathological study demonstrated a WHO Grade I ganglioglioma.

Description:

We report a case of a 58-year-old male who presented with hearing loss, tinnitus, and vertigo. Initial magnetic resonance imaging revealed bilateral nonenhancing IAC/CPA tumors. Based on this finding, a presumptive diagnosis of neurofibromatosis Type II was made, which was initially managed conservatively with close observation. He returned for follow-up with worsening vertigo and tinnitus, thus prompting the decision to proceed with surgical resection of the symptomatic mass. Intriguingly, pathological study demonstrated a WHO Grade I ganglioglioma.

Conclusion:

This is the first reported case of bilateral IAC/CPA gangliogliomas. When evaluating bilateral IAC/CPA lesions with unusual imaging characteristics, ganglioglioma should be included in the differential diagnosis.

The Anterior Subcallosal Approach to Third Ventricular and Suprasellar Lesions: Anatomical Description and Technical Note

BACKGROUND

Surgical access to the third ventricle is challenging, given the depth of the operative field and close proximity of vital neural structures that must be traversed. For anterior third ventricular lesions, approach options include anterior transcallosal or transcortical, subfrontal, frontotemporal, or endonasal. The subcallosal approach, a translamina terminalis approach, is unique in that the surgical corridor is just below the corpus callosum, minimizes retraction and preserves corpus callosum integrity. Case examples are provided, and an anatomical study delineating the dimensions of the surgical corridor is performed.

METHODS

Two latex-injected cadaver heads were used to describe the subcallosal corridor. A magnetic resonance imaging scan was obtained and registered with neuronavigation for correlative anatomical illustration. Depth, dimensions, and cross-sectional area were measured for the subcommunicating and supracommunicating corridors.

RESULTS

The surgical depth for anterior transcallosal, subcallosal, and subfrontal approaches was 7.5 cm, 7.7 cm, and 7.6 cm respectively. The average corridor dimensions for the subcallosal approach were 14.75 × 6.63 mm compared with 8.88 × 5.38 mm for the subcommunicating corridor. Cross-sectional area of the subcommunicating corridor was 30.62 mm(2) compared with 80.42 mm(2) for supracommunicating. This was easily enlarged to 156.62 mm(2) with gentle retraction.

CONCLUSIONS

The anterior subcallosal approach is a safe approach for lesions of the third ventricle that avoids splitting the corpus callosum and resecting unnecessary brain and minimizes brain retraction. This corridor is superior to the traditional subfrontal approach in terms of working space and compares favorably to the anterior transcallosal approach without disrupting the corpus callosum.

Long-term growth and alignment after occipitocervical and atlantoaxial fusion with rigid internal fixation in young children

OBJECT The long-term consequences of atlantoaxial (AA) and occipitocervical (OC) fusion and instrumentation in young children are unknown. Anecdotal reports have raised concerns regarding altered growth and alignment of the cervical spine after surgical intervention. The purpose of this study was to determine the long-term effects of these surgeries on the growth and alignment of the maturing spine. METHODS A multiinstitutional retrospective chart review was conducted for patients less than or equal to 6 years of age who underwent OC or AA fusion with rigid instrumentation at 9 participating centers. All patients had at least 3 years of clinical and radiographic follow-up data and radiographically confirmed fusion. Preoperative, immediate postoperative, and most recent follow-up radiographs and/or CT scans were evaluated to assess changes in spinal growth and alignment. RESULTS Forty children (9 who underwent AA fusion and 31 who underwent OC fusion) were included in the study (mean follow-up duration 56 months). The mean vertical growth over the fused levels in the AA fusion patients represented 30% of the growth of the cervical spine (range 10%-50%). Three different vertical growth patterns of the fusion construct developed among the 31 OC fusion patients during the follow-up period: 1) 16 patients had substantial growth (13%-46% of the total growth of the cervical spine); 2) 9 patients had no meaningful growth; and 3) 6 patients, most of whom presented with a distracted atlantooccipital dislocation, had a decrease in the height of the fused levels (range 7-23 mm). Regarding spinal alignment, 85% (34/40) of the patients had good alignment at follow-up, with straight or mildly lordotic cervical curvatures. In 1 AA fusion patient (11%) and 5 OC fusion patients (16%), we observed new hyperlordosis (range 43°-62°). There were no cases of new kyphosis or swan-neck deformity, evidence of subaxial instability, or unintended subaxial fusion. No preoperative predictors of these growth patterns or alignment were evident. CONCLUSIONS These results demonstrate that most young children undergoing AA and OC fusion with rigid internal fixation continue to have good cervical alignment and continued growth within the fused levels during a prolonged follow-up period. However, some variability in vertical growth and alignment exists, highlighting the need to continue close long-term follow-up.

Protective and Toxic Neuroinflammation in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a clinically heterogeneous disorder characterized by loss of motor neurons, resulting in paralysis and death. Multiple mechanisms of motor neuron injury have been implicated based upon the more than 20 different genetic causes of familial ALS. These inherited mutations compromise diverse motor neuron pathways leading to cell-autonomous injury. In the ALS transgenic mouse models, however, motor neurons do not die alone. Cell death is noncell-autonomous dependent upon a well orchestrated dialogue between motor neurons and surrounding glia and adaptive immune cells. The pathogenesis of ALS consists of 2 stages: an early neuroprotective stage and a later neurotoxic stage. During early phases of disease progression, the immune system is protective with glia and T cells, especially M2 macrophages/microglia, and T helper 2 cells and regulatory T cells, providing anti-inflammatory factors that sustain motor neuron viability. As the disease progresses and motor neuron injury accelerates, a second rapidly progressing phase develops, characterized by M1 macrophages/microglia, and proinflammatory T cells. In rapidly progressing ALS patients, as in transgenic mice, neuroprotective regulatory T cells are significantly decreased and neurotoxicity predominates. Our own therapeutic efforts are focused on modulating these neuroinflammatory pathways. This review will focus on the cellular players involved in neuroinflammation in ALS and current therapeutic strategies to enhance neuroprotection and suppress neurotoxicity with the goal of arresting the progressive and devastating nature of ALS.

Ogilvie's syndrome after pediatric spinal deformity surgery: successful treatment with neostigmine

Ogilvie's syndrome is a rare and potentially fatal disease that can easily be mistaken for postoperative ileus. Also known as acute colonic pseudo-obstruction, early recognition and diagnosis of the syndrome allows for treatment prior to bowel perforation and requisite abdominal surgery. The authors report a case of Ogilvie's syndrome following spinal deformity correction and tethered cord release in an adolescent who presented with acute abdominal distension, nausea, and vomiting on postoperative Day 0. The patient was initially diagnosed with adynamic ileus and treated conservatively with bowel rest, reduction in narcotic dosage, and a regimen of stool softeners, laxatives, and enemas. Despite this treatment, her clinical course failed to improve, and she demonstrated significant colonic distension radiographically. Intravenous neostigmine was administered as a bolus with a rapid and dramatic response. This case is the first reported instance of neostigmine use for Ogilvie's syndrome treatment following a pediatric neurosurgical operation.

Mixed Reality Ventriculostomy Simulation: Experience in Neurosurgical Residency

BACKGROUND:

Medicine and surgery are turning toward simulation to improve on limited patient interaction during residency training. Many simulators today use virtual reality with augmented haptic feedback with little to no physical elements. In a collaborative effort, the University of Florida Department of Neurosurgery and the Center for Safety, Simulation & Advanced Learning Technologies created a novel “mixed” physical and virtual simulator to mimic the ventriculostomy procedure. The simulator contains all the physical components encountered for the procedure with superimposed 3-D virtual elements for the neuroanatomical structures.

OBJECTIVE:

To introduce the ventriculostomy simulator and its validation as a necessary training tool in neurosurgical residency.

METHODS:

We tested the simulator in more than 260 residents. An algorithm combining time and accuracy was used to grade performance. Voluntary postperformance surveys were used to evaluate the experience.

RESULTS:

Results demonstrate that more experienced residents have statistically significant better scores and completed the procedure in less time than inexperienced residents. Survey results revealed that most residents agreed that practice on the simulator would help with future ventriculostomies.

CONCLUSION:

This mixed reality simulator provides a real-life experience, and will be an instrumental tool in training the next generation of neurosurgeons. We have now implemented a standard where incoming residents must prove efficiency and skill on the simulator before their first interaction with a patient.

Critical role of PI3K/Akt/GSK3β in motoneuron specification from human neural stem cells in response to FGF2 and EGF

Fibroblast growth factor (FGF) and epidermal growth factor (EGF) are critical for the development of the nervous system. We previously discovered that FGF2 and EGF had opposite effects on motor neuron differentiation from human fetal neural stem cells (hNSCs), but the underlying mechanisms remain unclear. Here, we show that FGF2 and EGF differentially affect the temporal patterns of Akt and glycogen synthase kinase 3 beta (GSK3β) activation. High levels of phosphatidylinositol 3-kinase (PI3K)/Akt activation accompanied with GSK3β inactivation result in reduction of the motor neuron transcription factor HB9. Inhibition of PI3K/Akt by chemical inhibitors or RNA interference or overexpression of a constitutively active form of GSK3β enhances HB9 expression. Consequently, PI3K inhibition increases hNSCs differentiation into HB9⁺/microtubule-associated protein 2 (MAP2)⁺ motor neurons in vitro. More importantly, blocking PI3K not only enhances motor neuron differentiation from hNSCs grafted into the ventral horn of adult rat spinal cords, but also permits ectopic generation of motor neurons in the dorsal horn by overriding environmental influences. Our data suggest that FGF2 and EGF affect the motor neuron fate decision in hNSCs differently through a fine tuning of the PI3K/AKT/GSK3β pathway, and that manipulation of this pathway can enhance motor neuron generation.