Pulsed Electromagnetic Fields Accelerate Sensorimotor Recovery Following Experimental Disc Herniation.

STUDY DESIGN: An experimental animal study. OBJECTIVE: The aim of this study was to investigate the effect of pulsed electromagnetic fields (PEMF) on recovery of sensorimotor function in a rodent model of disc herniation (DH). SUMMARY OF BACKGROUND DATA: Radiculopathy associated with DH is mediated by proinflammatory cytokines. Although we have demonstrated the anti-inflammatory effects of PEMF on various tissues, we have not investigated the potential therapeutic effect of PEMF on radiculopathy resulting from DH. METHODS: Nineteen rats were divided into three groups: positive control (PC; left L4 nerve ligation) (n = 6), DH alone (DH; exposure of left L4 dorsal root ganglion [DRG] to harvested nucleus pulposus and DRG displacement) (n = 6), and DH + PEMF (n = 7). Rodents from the DH + PEMF group were exposed to PEMF immediately postoperatively and for 3 hours/day until the end of the study. Sensory function was assessed via paw withdrawal thresholds to non-noxious stimuli preoperatively and 1 and 3 days postoperatively, and every 7 days thereafter until 7 weeks after surgery. Motor function was assessed via DigiGait treadmill analysis preoperatively and weekly starting 7 days following surgery until 7 weeks following surgery. RESULTS: All groups demonstrated marked increases in the left hindlimb response threshold postoperatively. However, 1 week following surgery, there was a significant effect of condition on left hindlimb withdrawal thresholds (one-way analysis of variance: F = 3.82, df = 2, P = 0.044) where a more rapid recovery to baseline threshold was evident for DH + PEMF compared to PC and DH alone. All groups demonstrated gait disturbance postoperatively. However, DH + PEMF rodents were able to regain baseline gait speeds before DH and PC rodents. When comparing gait parameters, DH + PEMF showed consistently less impairment postoperatively suggesting that PEMF treatment was associated with less severe gait disturbance. CONCLUSION: These data demonstrate that PEMF accelerates sensorimotor recovery in a rodent model of DH, suggesting that PEMF may be reasonable to evaluate for the clinical management of patients with herniation-associated radiculopathy.Level of Evidence: N/A.

Immunologic aspects of viral therapy for glioblastoma and implications for interactions with immunotherapies.

INTRODUCTION: The treatment for glioblastoma (GBM) has remained unchanged for the past decade, with only minimal improvements in patient survival. As a result, novel treatments are needed to combat this devastating disease. Immunotherapies are treatments that stimulate the immune system to attack tumor cells and can be either local or systemically delivered. Viral treatments can lead to direct tumor cell death through their natural lifecycle or through the delivery of a suicide gene, with the potential to generate an anti-tumor immune response, making them interesting candidates for combinatorial treatment with immunotherapy. METHODS: We review the current literature surrounding the interactions between oncolytic viruses and the immune system as well as the use of oncolytic viruses combined with immunotherapies for the treatment of GBM. RESULTS: Viral therapies have exhibited preclinical efficacy as single-agents and are being investigated in that manner in clinical trials. Oncolytic viruses have significant interactions with the immune system, although this can also vary depending on the strain of virus. Combinatorial treatments using both oncolytic viruses and immunotherapies have demonstrated promising preclinical findings. CONCLUSIONS: Studies combining viral and immunotherapeutic treatment modalities have provided exciting results thus far and hold great promise for patients with GBM. Additional studies assessing the clinical efficacy of these treatments as well as improved preclinical modeling systems, safety mechanisms, and the balance between treatment efficacy and immune-mediated viral clearance should be considered.

A Type II Split Cord Malformation in an Adult Patient: An Operative Case Report.

BACKGROUND AND IMPORTANCE: Split cord malformations (SCMs) are rare conditions in which the spinal cord is split into two hemicords within either a single thecal sac or two separate thecal sacs. The hemicords are typically split by a bony or fibrous structure. We present an adult patient who presented with a type II SCM with tethered cord. This is the first case of such a presentation with an accompanying intraoperative video. Unusual features of the case were the presence of an incomplete fibrous septum and lack of a discrete filum terminale. CLINICAL PRESENTATION: A 50-yr-old woman presented with back pain, radiculopathy, urinary urgency, and episodic fecal incontinence. Her exam was notable for weakness of the right extensor hallicus longus. Imaging showed an SCM extending from L3 to S1, a fibrous septum located at L4-5, and a low-lying conus at S4. She was treated with a decompressive L3-S4 laminectomy and disconnection of all the dural attachment points. She required lumbar drain placement postoperatively and reoperation for wound dehiscence and persistent pseudomeningocele. At the time of last follow-up, she was neurologically intact with improvement in bowel/bladder function. CONCLUSION: SCM is an uncommon presentation in adults and is often accompanied by findings of skin stigmata, tethered cord, and other central nervous system/skeletal anomalies. Obtaining full multimodal imaging is critical to understanding subtle anatomic variations that can pose operative challenges. We report the treatment of an adult patient with type II SCM, and provide an intraoperative video demonstrating the removal of an incomplete midline fibrous septum.

Injury volume extracted from MRI predicts neurologic outcome in acute spinal cord injury: A prospective TRACK-SCI pilot study.

Conventional MRI measures of traumatic spinal cord injury severity largely rely on 2-dimensional injury characteristics such as intramedullary lesion length and cord compression. Recent advances in spinal cord (SC) analysis have led to the development of a robust anatomic atlas incorporated into an open-source platform called the Spinal Cord Toolbox (SCT) that allows for quantitative volumetric injury analysis. In the current study, we evaluate the prognostic value of volumetric measures of spinal cord injury on MRI following registration of T2-weighted (T2w) images and segmented lesions from acute SCI patients with a standardized atlas. This IRB-approved prospective cohort study involved the image analysis of 60 blunt cervical SCI patients enrolled in the TRACK-SCI clinical research protocol. Axial T2w MRI data obtained within 24 h of injury were processed using the SCT. Briefly, SC MRIs were automatically segmented using the sct_deepseg_sc tool in the SCT and segmentations were manually corrected by a neuro-radiologist. Lesion volume data were used as predictor variables for correlation with lower extremity motor scores at discharge. Volumetric MRI measures of T2w signal abnormality comprising the SCI lesion accurately predict lower extremity motor scores at time of patient discharge. Similarly, MRI measures of injury volume significantly correlated with motor scores to a greater degree than conventional 2-D metrics of lesion size. The volume of total injury and of injured spinal cord motor regions on T2w MRI is significantly and independently associated with neurologic outcome at discharge after injury.

The neurosurgery applicant's "arms race": analysis of medical student publication in the Neurosurgery Residency Match.

OBJECTIVE: Neurosurgery is consistently one of the most competitive specialties for resident applicants. The emphasis on research in neurosurgery has led to an increasing number of publications by applicants seeking a successful residency match. The authors sought to produce a comprehensive analysis of research produced by neurosurgical applicants and to establish baseline data of neurosurgery applicant research productivity given the increased emphasis on research output for successful residency match. METHODS: A retrospective review of publication volume for all neurosurgery interns in 2009, 2011, 2014, 2016, and 2018 was performed using PubMed and Google Scholar. Missing data rates were 11% (2009), 9% (2011), and < 5% (all others). The National Resident Matching Program report "Charting Outcomes in the Match" (ChOM) was interrogated for total research products (i.e., abstracts, presentations, and publications). The publication rates of interns at top 40 programs, students from top 20 medical schools, MD/PhD applicants, and applicants based on location of residency program and medical school were compared statistically against all others. RESULTS: Total publications per neurosurgery intern (mean ± SD) based on PubMed and Google Scholar were 5.5 ± 0.6 in 2018 (1.7 ± 0.3, 2009; 2.1 ± 0.3, 2011; 2.6 ± 0.4, 2014; 3.8 ± 0.4, 2016), compared to 18.3 research products based on ChOM. In 2018, the mean numbers of publications were as follows: neurosurgery-specific publications per intern, 4.3 ± 0.6; first/last author publications, 2.1 ± 0.3; neurosurgical first/last author publications, 1.6 ± 0.2; basic science publications, 1.5 ± 0.2; and clinical research publications, 4.0 ± 0.5. Mean publication numbers among interns at top 40 programs were significantly higher than those of all other programs in every category (p < 0.001). Except for mean number of basic science publications (p = 0.1), the mean number of publications was higher for interns who attended a top 20 medical school than for those who did not (p < 0.05). Applicants with PhD degrees produced statistically more research in all categories (p < 0.05) except neurosurgery-specific (p = 0.07) and clinical research (p = 0.3). While there was no statistical difference in publication volume based on the geographical location of the residency program, students from medical schools in the Western US produced more research than all other regions (p < 0.01). Finally, research productivity did not correlate with likelihood of medical students staying at their home institution for residency. CONCLUSIONS: The authors found that the temporal trend toward increased total research products over time in neurosurgery applicants was driven mostly by increased nonindexed research (abstracts, presentations, chapters) rather than by increased peer-reviewed publications. While we also identified applicant-specific factors (MD/PhDs and applicants from the Western US) and an outcome (matching at research-focused institutions) associated with increased applicant publications, further work will be needed to determine the emphasis that programs and applicants will need to place on these publications.

Pulsed electromagnetic fields reduce acute inflammation in the injured rat-tail intervertebral disc.

Pro-inflammatory cytokines are recognized contributors to intervertebral disc (IVD) degeneration and discogenic pain. We have recently reported the anti-inflammatory effect of pulsed electromagnetic fields (PEMF) on IVD cells in vitro. Whether these potentially therapeutic effects are sufficiently potent to influence disc health in vivo has not been demonstrated. We report here the effect of PEMF on acute inflammation arising from a rat-tail IVD injury model. Disc degeneration was induced by percutaneously stabbing the Co6-7, Co7-8, and Co8-9 levels using a 20-gauge needle. Seventy-two (72) rats were divided into three groups: sham control, needle stab, needle stab+PEMF. Treated rats were exposed to PEMF immediately following surgery and for either 4 or 7 days (4 hr/d). Stab and PEMF effects were evaluated by measuring inflammatory cytokine gene expression (RT-PCR) and protein levels (ELISA assay), anabolic and catabolic gene expression (RT-PCR), and histologic changes. We observed in untreated animals that at day 7 after injury, inflammatory cytokines (interleukin [IL]-6, tumor necrosis factor α, and IL-1ß) were significantly increased at both gene and protein levels (P < .05). Similarly, catabolic factors (MMP [metalloproteinases]-2, MMP-13 and the transcriptional factor NF-kß gene expression) were significantly increased (P < .05). At day 7, PEMF treatment significantly inhibited inflammatory cytokine gene and protein expression induced by needle stab injury (P < .05). At day 4, PEMF downregulated FGF-1 and upregulated MMP-2 compared to the stab-only group. These data demonstrate that previously reported anti-inflammatory effects of PEMF on disc cells carry over to the in vivo situation, suggesting potential therapeutic benefits. Though we observed an inhibitory effect of PEMF on acute inflammatory cytokine expression, a consistent effect was not observed for acute changes in disc histology and anabolic and catabolic factor expression. Therefore, these findings should be further investigated in studies of longer duration following needle-stab injury.