Search

Tendon is a vital musculoskeletal tissue that is prone to degeneration. Proper tendon maintenance requires complex interactions between extracellular matrix components that remain poorly understood. Collagen VI and biglycan are two matrix molecules that localize pericellularly within tendon and are critical regulators of tissue properties. While evidence suggests that collagen VI and biglycan interact within the tendon matrix, the relationship between the two molecules and its impact on tendon function remains unknown. We sought to elucidate potential coordinate roles of collagen VI and biglycan within tendon by defining tendon properties in knockout models of collagen VI, biglycan, or both molecules. We first demonstrated co-expression and co-localization of collagen VI and biglycan within the healing tendon, providing further evidence of cooperation between the two molecules during nascent tendon matrix formation. Deficiency in collagen VI and/or biglycan led to significant reductions in collagen fibril size and tendon mechanical properties. However, collagen VI-null tendons displayed larger reductions in fibril size and mechanics than seen in biglycan-null tendons. Interestingly, knockout of both molecules resulted in similar properties to collagen VI knockout alone. These results indicate distinct and non-additive roles for collagen VI and biglycan within tendon. This work provides better understanding of regulatory interactions between two critical tendon matrix molecules.

Introduction: COVID-19 is a disease that causes flu-like symptoms and difficulty breathing. Emerging in 2019, the COVID-19 pandemic has affected the entire world through restrictions and lockdowns. Multiple studies have compared the effects of COVID-19 on different types of head trauma, with each one producing different results. The goal of this study was to use state and hospital data to determine whether the COVID-19 pandemic had a significant impact on surgeries for traumatic brain injury (TBI)., Methods: Public state data on COVID-19 incidence, sourced from the Virginia Department of Health, was compared to hospital data of 352 patients receiving surgeries for TBI from a single major level-one trauma hospital in Northern Virginia. We used data from the three years before COVID-19 and the two years during the pandemic, using t-tests and Pearson correlation to analyze the data. This is a retrospective case review study on the number and age of patients receiving TBI surgery from March 2017 through February 2022 at Inova Fairfax Hospital in Northern Virginia to determine the impact of the COVID-19 pandemic on these factors., Results: When comparing the data, there was a 60% reduction in cases of operative TBI during the peak months of COVID-19 compared to the same months in previous years (p<0.005). Comparing data on the number of Virginia and Northern Virginia COVID-19 cases and data on the age of individuals undergoing TBI surgery four weeks later showed a statistically significant negative correlation (p<0.05) in which the average age of individuals undergoing TBI surgery was lower in the four-week block following a four-week block of increased COVID-19 incidence., Conclusion: Our findings indicate a correlation between the period of decreased activity from COVID-19 restrictions in Virginia and a decline in both the number of TBI surgeries and the age of individuals undergoing these surgeries., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Leiphart et al.)

Spinal epidural lipomatosis (SEL) is a common pathology of the lumbar spine. While the natural history is not well understood, there is a strong association with metabolic syndrome and endocrine dysfunction. Clinical presentation typically involves slow, progressive onset of radicular and myelopathic symptoms. Treatment primarily consists of weight loss, while surgery is reserved for refractory cases or acute cauda equina syndrome. We present a case of acute spinal cord injury (SCI) after trauma with underlying SEL in the cervicothoracic spine. Additionally, a literature review using a MEDLINE search of the English literature through April 2020 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed to identify all documented cases of acute spinal cord injury with underlying SEL. A 72-year-old obese male with insulin-dependent diabetes mellitus presented with subacute bilateral lower extremity weakness after a fall with a flank injury three days prior to evaluation. Within hours of admission, the patient acutely progressed to paraplegia and sensory loss below the T6 level consistent with an ASIA (American Spinal Injury Association) A spinal cord injury. No fracture or dislocation was identified on CT imaging. MRI of the thoracic spine revealed spinal cord compression secondary to extensive posterior epidural lipomatosis with resultant anterior displacement of the thecal sac. The patient underwent emergent T2-T9 laminectomy for decompression. Post-operatively, the patient regained sensation below the level of injury. A review of the literature reviewed no published articles on cases of complete spinal cord injury secondary to underlying SEL without associated fracture. Finally, we present the first report of an acute spinal cord injury in the setting of SEL without fracture. Our case demonstrates that SEL outside the lumbar spine confers increased risk for SCI following trauma. Patients with cervicothoracic SEL may require close neurological observation and timely surgical decompression., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Mugge et al.)

Background  There is a significant upfront cost for the use of neuromodulation devices. The high cost of these devices may lead to disproportionate application in geographical regions with different levels of financial resources. The purpose of this study was to determine if there is geographic based economic inequity in the application of neuromodulation devices in the United States. Methods  Population and average household income data by county from the year 2010 were obtained from publicly available databases on the US Census website. The number of stimulators sold by county in the years 2009 and 2010 were provided by two of the four neuromodulation companies with commercially available products. Pearson correlation and t-test statistics were performed. Results  Of the 3142 U.S. counties analyzed, only 689 placed neuromodulation devices during this period of time. There was a difference in average household income between counties with device implants ($49,663) and counties with no device implants ($41,314), which was statistically significant (p<0.001). Conclusion  Analysis of neuromodulation devices placed in 2009 and 2010 from 50% of neuromodulation companies demonstrated that there was an income disparity between counties in which implantation of devices occurred and counties in which there were no device implantations., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2019, Leiphart et al.)

Insular epilepsy often goes under-recognized and misdiagnosed due to the similarity of its features with temporal lobe epilepsy and the common exclusion of the insula during intracranial electroencephalography (iEEG). Here, we present a case of medically refractory epilepsy in a 43-year-old male with a 12-year history of tonic-clonic seizures. Insular epilepsy cases are often considered for diagnosis in the setting of abnormal insular pathology, such as a low-grade central nervous system (CNS) lesion. This is a unique case of non-lesional insular epilepsy, successfully managed by the resection of the insular cortex., Competing Interests: The authors have declared that no competing interests exist.

The treatment protocol of status epilepticus has many associated toxicities so there is interest in alternate nonmedicinal therapies for managing New Onset Refractory Status Epilepticus (NORSE) patients. Vagus nerve stimulation (VNS) is an FDA-approved therapy for refractory epilepsy that has been shown to decrease the frequency and severity of seizures. We present the case of a patient with new-onset refractory status epilepticus (NORSE) whose seizures were successfully treated with vagus nerve stimulation. A 25-year-old male with no history of epilepsy or other neurological disorders presented with altered mental status and generalized tonic-clonic seizures following a two-week history of an upper respiratory tract infection. Lumbar puncture showed neutrophilic pleocytosis, and he was treated for bacterial and viral meningoencephalitis. In spite of treatment, his seizures began increasing in frequency. On day three, the patient entered status epilepticus (SE) refractory to intensive pharmacotherapy with maximal doses of valproate, levetiracetam, and propofol. On day four, SE remained refractory, so pentobarbital was introduced with targeted burst suppression pattern on electroencephalography (EEG). Patient continued to be refractory to these measures, so a vagus nerve stimulator (VNS) was implanted (day eight). Following VNS implantation, EEG demonstrated significant reduction of seizure activity and subsequent magnet swiping continued aborting electrographic seizures. No SE or electrographic seizures were reported for seventy-two hours, but few occasional discharges were reported. Seizures eventually recurred on day fourteen and the patient succumbed to his multiple comorbidities on day seventeen. Due to the efficacy of VNS in refractory epilepsy, there was interest in using it in refractory status epilepticus. Multiple case reports have described a benefit from implantation of VNS in the treatment of SE. The successful use of VNS to acutely terminate status epilepticus for seventy-two hours in this critically ill patient adds to current evidence that there is utility in using VNS for refractory status epilepticus.

Cervical radiculopathy and peripheral nerve pathology often compete in the differential diagnosis of extremity pain, weakness, and numbness, and frequently, coexist. In this report, we describe a 73-year-old male with a previously asymptomatic left anteromedial proximal upper arm mass, who presented with progressive radicular arm pain, proximal and distal upper extremity weakness, and hand numbness. Clinical investigation revealed a prominent C6-7 disc herniation and a median nerve sheath tumor, with electromyography (EMG)/nerve conduction velocity (NCV) studies suggestive of acute radiculopathy. He was treated in a staged surgical fashion, with the nerve sheath tumor resection first, followed by a standard C6-7 anterior cervical discectomy and fusion (ACDF) two weeks later. The patient made a full recovery. We provide a literature review and discussion of the "double crush" hypothesis., Competing Interests: The authors have declared that no competing interests exist.

Objective:   The objective of this study is to present a novel approach to the treatment of thoracic radiculitis following Brown-Sequard syndrome with peripheral nerve field stimulation (PNFS). Furthermore, we endeavor to discuss the role of PNFS in the management of refractory neuropathic pain conditions including post-traumatic and post-surgical neuropathy particularly with regards to the post-surgical spine., Materials and Methods:   Presented is a 57-year-old man with history of thoracic microdiscectomy resulting in Brown-Sequard syndrome presented with chronic post-operative thoracic radicular pain radiating to the abdomen, refractory to conservative management. The patient underwent three intercostal nerve blocks from T7 to T9 with transient symptomatic relief. The patient's options were limited to chemomodulation, neuromodulation, or selective intercostal nerve surgical neurectomy. He subsequently underwent a PNFS trial and reported >75% pain reduction. Permanent percutaneous PNFS electrodes were implanted subcutaneously over the right T7 and T9 intercostal nerves and replicated the trial results., Results:   Neuromodulation produced pain relief with >90% improvement in pain compared with baseline both during the trial and following permanent implantation of the PNFS system., Conclusion:   Chronic radicular pain may be difficult to manage in the post-surgical patient and often requires the use of multiple therapeutic modalities. In this case, we successfully utilized PNFS as it demonstrated greater technical feasibility when compared with dorsal column stimulation and repeat surgery; therefore, it may be considered for the management of post-surgical neuropathy. Further controlled studies are needed to evaluate the efficacy of PNFS as a treatment option., (© 2011 International Neuromodulation Society.)

Intrathecal (IT) administration of opiate analgesics has become a popular method of pain control in patients with pain of both malignant and nonmalignant origin. Therapeutic efficacy for nonmalignant pain states might be improved by having a broader range of available pharmacologic agents for intrathecal administration. Toward this aim, we have applied a new model of neuropathic pain in the rat to evaluate the relative analgesic efficacy and potential cross tolerance of both acutely and chronically administered IT morphine (MS) and tizanidine (TZ), an alpha 2-adrenergic agonist. Under anesthesia, 225 Sprague-Dawley male rats underwent unilateral multiple partial suture ligation of the sciatic nerve. This produces a syndrome similar to human neuropathic pain. Chronic lumbar IT cannulae were placed via the cisterna magna. Seven days after surgery, animals were tested for spontaneous ambulation and paw pinch tolerance. These tests correlate with human clinical observations of chronic pain and hyperpathia. For the acute drug administration, animals were then given saline, 10, 20, or 30 micrograms IT MS or 10, 25 or 50 micrograms IT TZ and testing was repeated. Preliminary results suggest that MS, in a dose-dependent manner, significantly decreased abnormal limb withdrawal from the floor while ambulating and increased paw pinch withdrawal latency to cutoff values (p < or = 0.01 in all tests). IT MS had significant effects on pain sensation in the operated and unoperated limbs, increasing latencies to cutoff and nonspecifically inhibiting pain transmission. IT TZ had a similar effect on decreasing limb withdrawal from the floor, but paw pinch withdrawal latency was increased only to the normal range, not to cutoff values. These effects were also dose-dependent. For chronic drug administration, after baseline testing, osmotic minipumps (Alza, Palo Alto, Calif.) delivering either saline, 60 or 120 micrograms/day MS, or 75 or 150 micrograms/day TZ were attached to the IT catheter. Testing was done on days 1, 4, 7 and 14 after pump attachment. On day 14, the animals were given an IT bolus of the noninfused drug (50 micrograms tizanidine or 30 micrograms morphine) and the tests were repeated to determine degree of cross tolerance. Initially, chronic MS and TZ administration produced a similar degree of analgesia seen with results obtained with acute administration. The animals rapidly became tolerant to these agents so that by day 4, neither drug had an analgesic effect. No significant cross tolerance between MS and TZ was observed. Thus, both IT MS and TZ are analgesic in experimental chronic neuropathic pain.(ABSTRACT TRUNCATED AT 400 WORDS)

The difference between implicit and explicit memory was examined using event-related potentials (ERP). 16 college students read a study list of 100 words (50 high-emotion and 50 low-emotion) from a video monitor. They then performed a perceptual identification (P.I.) task in which they attempted to identify each of a series of 100 words (including 50 from the study list) presented at recognition threshold. Finally, the subjects performed a yes-no recognition task in which they were presented with the other 50 words from the first list and 50 new words (suprathreshold), and they had to identify which ones had been seen in the study list. Subjects were more likely to identify studied than nonstudied words in the perceptual identification task; there was no effect of emotion. In the yes-no recognition task, more high than low-emotion words were responded to correctly for the old words, whereas more low than high-emotion words were responded to correctly for the new words. Data from 11 of the subjects contained enough artifact-free trials for ERP analysis. Analysis revealed that in both the perceptual identification task and the yes-no recognition task, P3 amplitude was larger for old than new words, and emotionality had no effect. Analysis of ERPs in the perceptual identification task averaged according to behavioral response, as well as according to prior study effect showed that P3 amplitude was larger for the studied words than non-studied words, regardless of behavioral response. This effect is electrophysiological evidence that a specific event occurs in the brain in response to the presentation of studied words, whether or not those words are consciously perceived. P3 latency differed as a function of previous study in the yes-no task but not the perceptual identification task.