Culture substrate stiffness impacts human myoblast contractility-dependent proliferation and nuclear envelope wrinkling.

Understanding how biophysical and biochemical microenvironmental cues together influence the regenerative activities of muscle stem cells and their progeny is crucial in strategizing remedies for pathological dysregulation of these cues in aging and disease. In this study, we investigated the cell-level influences of extracellular matrix (ECM) ligands and culture substrate stiffness on primary human myoblast contractility and proliferation within 16 h of plating and found that tethered fibronectin led to stronger stiffness-dependent responses compared to laminin and collagen. A proteome-wide analysis further uncovered cell metabolism, cytoskeletal and nuclear component regulation distinctions between cells cultured on soft and stiff substrates. Interestingly, we found that softer substrates increased the incidence of myoblasts with a wrinkled nucleus, and that the extent of wrinkling could predict Ki67 (also known as MKI67) expression. Nuclear wrinkling and Ki67 expression could be controlled by pharmacological manipulation of cellular contractility, offering a potential cellular mechanism. These results provide new insights into the regulation of human myoblast stiffness-dependent contractility response by ECM ligands and highlight a link between myoblast contractility and proliferation.

Lipidomic-Based Approach to 10 s Classification of Major Pediatric Brain Cancer Types with Picosecond Infrared Laser Mass Spectrometry.

Picosecond infrared laser mass spectrometry (PIRL-MS) is shown, through a retrospective patient tissue study, to differentiate medulloblastoma cancers from pilocytic astrocytoma and two molecular subtypes of ependymoma (PF-EPN-A, ST-EPN-RELA) using laser-extracted lipids profiled with PIRL-MS in 10 s of sampling and analysis time. The average sensitivity and specificity values for this classification, taking genomic profiling data as standard, were 96.41 and 99.54%, and this classification used many molecular features resolvable in 10 s PIRL-MS spectra. Data analysis and liquid chromatography coupled with tandem high-resolution mass spectrometry (LC-MS/MS) further allowed us to reduce the molecular feature list to only 18 metabolic lipid markers most strongly involved in this classification. The identified 'metabolite array' was comprised of a variety of phosphatidic and fatty acids, ceramides, and phosphatidylcholine/ethanolamine and could mediate the above-mentioned classification with average sensitivity and specificity values of 94.39 and 98.78%, respectively, at a 95% confidence in prediction probability threshold. Therefore, a rapid and accurate pathology classification of select pediatric brain cancer types from 10 s PIRL-MS analysis using known metabolic biomarkers can now be available to the neurosurgeon. Based on retrospective mining of 'survival' versus 'extent-of-resection' data, we further identified pediatric cancer types that may benefit from actionable 10 s PIRL-MS pathology feedback. In such cases, aggressiveness of the surgical resection can be optimized in a manner that is expected to benefit the patient's overall or progression-free survival. PIRL-MS is a promising tool to drive such personalized decision-making in the operating theater.

Metabolic Lipids in Melanoma Enable Rapid Determination of Actionable BRAF-V600E Mutation with Picosecond Infrared Laser Mass Spectrometry in 10 s.

Rapid molecular profiling of biological tissues with picosecond infrared laser mass spectrometry (PIRL-MS) has enabled the detection of clinically important histologic types and molecular subtypes of human cancers in as little as 10 s of data collection and analysis time. Utilizing an engineered cell line model of actionable BRAF-V600E mutation, we observed statistically significant differences in 10 s PIRL-MS molecular profiles between BRAF-V600E and BRAF-wt cells. Multivariate statistical analyses revealed a list of mass-to-charge (m/z) values most significantly responsible for the identification of BRAF-V600E mutation status in this engineered cell line that provided a highly controlled testbed for this observation. These metabolites predicted BRAF-V600E expression in human melanoma cell lines with greater than 98% accuracy. Through chromatography and tandem mass spectrometry analysis of cell line extracts, a 30-member "metabolite array" was characterized for determination of BRAF-V600E expression levels in subcutaneous melanoma xenografts with an average sensitivity and specificity of 95.6% with 10 s PIRL-MS analysis. This proof-of-principle work warrants a future large-scale study to identify a metabolite array for 10 s determination of actionable BRAF-V600E mutation in human tissue to guide patient care.

Picosecond Infrared Laser Mass Spectrometry Identifies a Metabolite Array for 10 s Diagnosis of Select Skin Cancer Types: A Proof-of-Concept Feasibility Study.

Currently, a large number of skin biopsies are taken for each true skin cancer case detected, creating a need for a rapid, high sensitivity, and specificity skin cancer detection tool to reduce the number of unnecessary biopsies taken from benign tissue. Picosecond infrared laser mass spectrometry (PIRL-MS) using a hand-held sampling probe is reported to detect and classify melanoma, squamous cell carcinoma, and normal skin with average sensitivity and specificity values of 86-95% and 91-98%, respectively (at a 95% confidence level) solely requiring 10 s or less of total data collection and analysis time. Classifications are not adversely affected by specimen's quantity of melanin pigments and are mediated by a number of metabolic lipids, further identified herein as potential biomarkers for skin cancer-type differentiation, 19 of which were sufficient here (as a fully characterized metabolite array) to provide high specificity and sensitivity classification of skin cancer types. In situ detection was demonstrated in an intradermal melanoma mouse model wherein in vivo sampling did not cause significant discomfort. PIRL-MS sampling is further shown to be compatible with downstream gross histopathologic evaluations despite loss of tissue from the immediate laser sampling site(s) and can be configured using selective laser pulses to avoid thermal damage to normal skin. Therefore, PIRL-MS may be employed as a decision-support tool to reduce both the subjectivity of clinical diagnosis and the number of unnecessary biopsies currently required for skin cancer screening.

Mass Spectrometry Imaging Reveals a Gradient of Cancer-like Metabolic States in the Vicinity of Cancer Not Seen in Morphometric Margins from Microscopy.

Spatially resolved ambient mass spectrometry imaging methods have gained popularity to characterize cancer sites and their borders using molecular changes in the lipidome. This utility, however, is predicated on metabolic homogeneity at the border, which would create a sharp molecular transition at the morphometric borders. We subjected murine models of human medulloblastoma brain cancer to mass spectrometry imaging, a technique that provides a direct readout of tissue molecular content in a spatially resolved manner. We discovered a distance-dependent gradient of cancer-like lipid molecule profiles in the brain tissue within 1.2 mm of the cancer border, suggesting that a cancer-like state progresses beyond the histologic border, into the healthy tissue. The results were further corroborated using orthogonal liquid chromatography and mass spectrometry (LC-MS) analysis of selected tissue regions subjected to laser capture microdissection. LC-MS/MS analysis for robust identification of the affected molecules implied changes in a number of different lipid classes, some of which are metabolized from the essential docosahexaenoic fatty acid (DHA) present in the interstitial fluid. Metabolic molecular borders are thus not as sharp as morphometric borders, and mass spectrometry imaging can reveal molecular nuances not observed with microscopy. Caution must be exercised in interpreting multimodal imaging results stipulated on a coincidental relationship between metabolic and morphometric borders of cancer, at least within animal models used in preclinical research.

Dual Laser and Desorption Electrospray Ionization Mass Spectrometry Imaging Using the Same Interface.

For a more comprehensive characterization of molecular heterogeneities of matter, multimodal mass spectrometry imaging must be developed to take advantage of the complementarity of information available through different ionization mechanisms. We report the design, implementation, and performance validation of a laser desorption imaging interface composed of add-on components that adapt a commercial Desorption Electrospray Ionization Mass Spectrometry (DESI-MS) imaging interface for dual imaging of Picosecond Infrared Laser Mass Spectrometry (PIRL-MS) with DESI-MS. The interface utilizes hardware elements and data analysis pipelines already established for DESI-MS imaging, and was further validated in cancer margin assessments using human medulloblastoma cancers. The PIRL-MS images were robust and reproducible across multiple experimental runs on independently prepared xenograft tumors, and could be segmented into cancer and healthy regions in concordance with pathology using a variety of supervised and unsupervised clustering methods. The spectral quality and complexity obtained with this interface were examined with infiltrating and noninfiltrating tumors, and were comparable to other mass spectrometry analysis interfaces. The average PIRL-MS spectra from spatially resolved images could be used for robust cancer m/z model building to classify medulloblastoma cancer from healthy tissue without any misclassifications, an observation that held true over close to 70 sampling data points. While the unsupervised spectral analysis methods suggested a slight suppression of signal in the phospholipid range compared to the hand-held configuration, these changes were insufficient to hamper utility in cancer margin assessment with spatially resolved data obtained with our interface. Dual PIRL-MS and DESI-MS imaging of consecutive sections, as suggested by multivariate loading plots, revealed highly complementary molecular information with m/z values identifiable with one desorption method sufficient to reveal cancer regions being absent in another, further emphasizing the need for effective hardware and software interfaces for dual mass spectrometry imaging.

Rapid determination of the tumour stroma ratio in squamous cell carcinomas with desorption electrospray ionization mass spectrometry (DESI-MS): a proof-of-concept demonstration.

Squamous cell carcinomas constitute a major class of head & neck cancers, where the tumour stroma ratio (TSR) carries prognostic information. Patients affected by stroma-rich tumours exhibit a poor prognosis and a higher chance of relapse. As such, there is a need for a technology platform that allows rapid determination of the tumour stroma ratio. In this work, we provide a proof-of-principle demonstration that Desorption Electrospray Ionization Mass Spectrometry (DESI-MS) can be used to determine tumour stroma ratios. Slices from three independent mouse xenograft tumours from the human FaDu cell line were subjected to DESI-MS imaging, staining and detailed analysis using digital pathology methods. Using multivariate statistical methods we compared the MS profiles with those of isolated stromal cells. We found that m/z 773.53 [PG(18:1)(18:1) - H]-, m/z 835.53 [PI(34:1) - H]- and m/z 863.56 [PI(18:1)(18:0) - H]- are biomarker ions that can distinguish FaDu cancer from cancer associated fibroblast (CAF) cells. A comparison with DESI-MS analysis of controlled mixtures of the CAF and FaDu cells showed that the abundance of the biomarker ions above can be used to determine, with an error margin of close to 5% compared with quantitative pathology estimates, TSR values. This proof-of-principle demonstration is encouraging and must be further validated using human samples and a larger sample base. At maturity, DESI-MS thus may become a stand-alone molecular pathology tool providing an alternative rapid cancer assessment without the need for time-consuming staining and microscopy methods, potentially further conserving human resources.

Correction: Rapid determination of the tumour stroma ratio in squamous cell carcinomas with desorption electrospray ionization mass spectrometry (DESI-MS): a proof-of-concept demonstration.

Correction for 'Rapid determination of the tumour stroma ratio in squamous cell carcinomas with desorption electrospray ionization mass spectrometry (DESI-MS): a proof-of-concept demonstration' by Michael Woolman et al., Analyst, 2017, 142, 3250-3260.

Contrast Agent Mass Spectrometry Imaging Reveals Tumor Heterogeneity.

Mapping intratumoral heterogeneity such as vasculature and margins is important during intraoperative applications. Desorption electrospray ionization mass spectrometry (DESI-MS) has demonstrated potential for intraoperative tumor imaging using validated MS profiles. The clinical translation of DESI-MS into a universal label-free imaging technique thus requires access to MS profiles characteristic to tumors and healthy tissues. Here, we developed contrast agent mass spectrometry imaging (CA-MSI) that utilizes a magnetic resonance imaging (MRI) contrast agent targeted to disease sites, as a label, to reveal tumor heterogeneity in the absence of known MS profiles. Human breast cancer tumors grown in mice were subjected to CA-MSI using Gadoteridol revealing tumor margins and vasculature from the localization of [Gadoteridol+K](+) and [Gadoteridol+Na](+) adducts, respectively. The localization of the [Gadoteridol+K](+) adduct as revealed through DESI-MS complements the in vivo MRI results. DESI-MS imaging is therefore possible for tumors for which no characteristic MS profiles are established. Further DESI-MS imaging of the flux of the contrast agent through mouse kidneys was performed indicating secretion of the intact label.

Development of the cervical myelopathy severity index: a new patient reported outcome measure to quantify impairments and functional limitations.

BACKGROUND CONTEXT: Existing degenerative cervical myelopathy (DCM) severity scales have significant shortcomings, creating a strong impetus for the development of a practical measurement tool with sound psychometric properties. PURPOSE: This work reports the item generation and reduction of the Cervical Myelopathy Severity Index (CMSI), a new DCM patient-reported outcome measure of symptoms and functional limitations. DESIGN: Prospective observational study. PATIENT SAMPLE: Adult DCM patients belonging to one of three distinct treatment groups: (1) observation cohort, (2) preoperative surgical cohort, (3) 6 to 12 months postoperative cohort. OUTCOME MEASURES: Patient-reported outcome measure of symptoms and functional limitations. METHODS: Item generation was performed using semi-structured patient focus groups emphasizing symptoms experienced and functional limitations. Readability was assessed through think-aloud patient interviews. Item reduction involved surveys of DCM patients with a spectrum of disease severity and board-certified spine surgeons experienced in the treatment of DCM. A priori criteria for item removal included: patient median importance/severity <2 (of 4), 30% or more no severity (response of zero), item severity correlations ≤ 0.80 (Spearman), item severity reliability (weighted kappa <0.60) based on a 2-week interval and clinician median importance <2 with retention of items with very high clinical importance. RESULTS: There were 42 items generated from a combination of specialist input and patient focus groups. Items captured sensorimotor symptoms and limitations related to upper and lower extremities as well as sphincter dysfunction. Ninety-eight patients (43, 30, 25 observation, pre- and postsurgery respectively) and 51 surgeons completed the assessment. Twenty-three items remained after application of median importance and severity thresholds and weighted kappa cutoffs. After elimination of highly correlated (>0.80) items and combining two similar items, the final CMSI questionnaire list included 14 items. CONCLUSIONS: The CMSI is a new DCM patient-reported clinical measurement tool developed using patient and clinician input to inform item generation and reduction. Future work will evaluate the reliability, validity, and responsiveness of the CMSI in relation to existing myelopathy measurement indices.

Evaluation of Posterior Ligamentous Complex Injury in Thoracolumbar Burst Fractures: Correlation Analysis of CT and MRI Findings.

The goal of this study is to perform correlation analysis of Computed tomography (CT) and magnetic resonance imaging (MRI) results in posterior ligament complex (PLC) injury and define the morphological traits of thoracolumbar (TL) burst fractures connected to PLC injury. Forty patients with surgically repaired TL burst fractures between January 2013 and December 2020 were retrospectively analyzed. The patients were split into two groups for comparison based on MRI (Group P: patients with a confirmed or suspected PLC injury; Group N: patients with PLC injury denied). The radiographic morphological examination based on CT scans and clinical evaluation was performed and compared between two groups. The thoracolumbar injury classification and severity score (TLICS), the load sharing classification (LSC) scores, and the number of patients with neurological impairments were considerably greater in Group P. Loss of height of the fracture (loss height), local kyphosis of the fracture (local kyphosis), and supraspinous distance were significantly higher in Group P and significantly associated with PLC injuries indicating severe vertebral body destruction and traumatic kyphosis in multivariate logistic analysis [odds ratio: 1.90, 1.06, and 1.13, respectively]. Cutoff value for local kyphosis obtained from the receiver operating characteristic curve was 18.8. If local kyphosis is greater than 18.8 degrees on CT scans, we should take into account the probability of the highly damaged burst fracture associated with PLC injury. In this situation, we should carefully assess MRI to identify the spinal cord injury or spinal cord compression in addition to PLC injury because these instances likely present with neurological abnormalities.

Surgical treatment of spontaneous intracranial hypotension secondary to degenerative cervical spine pathology: a case report and literature review.

OBJECTIVE AND IMPORTANCE: A rare cause of intracranial hypotension is leakage of cerebrospinal fluid (CSF) through a dural breach from degenerative cervical spine pathology. To our knowledge there have been only four cases described in the English literature. Treatment is challenging and varies from case to case, with complete symptom resolution reported for only one patient. Herein we review the literature and describe our surgical management of a 46-year-old woman with symptomatic intracranial hypotension from the penetration of the cervical thecal sac. CLINICAL PRESENTATION: The patient presented with a 3-month history of progressive orthostatic headaches. Magnetic resonance imaging demonstrated bilateral subdural hematomas and pachymeningeal gadolinium enhancement. An anterior epidural CSF collection commencing at a C4-5 calcified disc protrusion and osteophyte was evident on a computed tomography spinal myelogram. INTERVENTION: After three unsuccessful lumbar blood patches, we elected to attempt surgical removal of the causative pathology with exposure and primary closure of the dural defect by anterior cervical discectomy as described previously. After resection of the disc-osteophyte complex and dural exposure, immediate high volume egression of CSF mixed with blood at the surgical site. The dural defect was not visible but CSF egression promptly ceased. Cervical corpectomy for greater exposure and primary repair of the defect has been described, but we considered this unwarranted and felt the intraoperative blood collection formed a local blood patch. A collagen dural substitute membrane was inserted through the discectomy space for reinforcement. CONCLUSION: Two months after this novel surgical blood patch procedure the patient was asymptomatic and follow-up imaging demonstrated complete resolution.

Spinal arachnoid web-a distinct entity of focal arachnopathy with favorable long-term outcome after surgical resection: analysis of a multicenter patient population.

BACKGROUND CONTEXT: Spinal arachnoid web (SAW) is a rare condition characterized by focal thickening of the arachnoid membrane causing displacement and compression of the spinal cord with progressive symptoms and neurological deficits. Recent reports and clinical experience suggest that SAW is a distinct entity with specific radiological findings and treatment strategies distinguishable from other arachnopathies and potential differential diagnoses. PURPOSE: To better define the diagnostic and clinical features, treatment options and outcomes of surgically treated SAW. STUDY DESIGN: Multicentric retrospective cohort study. PATIENT SAMPLE: Twelve cases of SAW surgically treated at three different centers. OUTCOME MEASURES: Self-reported and neurological outcome measurements (pain, sensory-motor deficits, vegetative dysfunctions) were assessed at follow-up timepoints. METHODS: Retrospective review of prospectively collected data on all patients surgically treated for SAW from three participating neurosurgical centers between 2014 and 2020. Clinicopathological data, including neurological presentation, radiological and histological findings and outcome data were analyzed. RESULTS: Twelve radiologically and surgically confirmed cases of SAW were analyzed. Mean patient age was 54.7 [±12.7], 67% were male. All SAWs were located in the posterior thoracic dural sac. On magnetic resonance imaging (MRI), the "scalpel sign" - a characteristic focal dorsal indentation of the spinal cord resembling a scalpel blade - was identified in all patients. A focal intramedullary syrinx was present in 83%. Preoperative clinical symptoms included signs of myelopathy, pain, weakness and sensory loss, most commonly affecting the trunk/upper back or lower extremities. Laminectomy or laminoplasty with intradural excision of the SAW was the surgical treatment of choice in all cases. Intraoperative ultrasound was valuable to visualize the cerebrospinal fluid (CSF) flow obstruction, confirm the SAW location before dura incision and to control adequacy of resection. After surgery, sensory loss and weakness in particular showed significant improvement. CONCLUSIONS: The present study comprises the largest series of surgically treated SAW, underscoring the unique clinical, radiographic, histopathological, and surgical findings. We want to emphasize SAW being a distinct entity of spinal arachnopathy with a favorable long-term outcome if diagnosed correctly and treated surgically. Intraoperative ultrasound aids visualizing the SAW before dural incision, as well as verifying restored CSF flow after resection.

Clinical and Radiological Clues of Traumatic Craniocervical Junction Injuries Requiring Occipitocervical Fusion to Early Diagnosis.

OBJECTIVE: The purpose of this study is to find the clinical and radiographic characteristics of traumatic craniocervical junction (CCJ) injuries requiring occipitocervical fusion (OC fusion) for early diagnosis and surgical intervention. METHODS: We retrospectively reviewed 12 patients with CCJ injuries presenting to St. Michaels Hospital in Toronto who underwent OC fusion and looked into the following variables; (1) initial trauma data on emergency room arrival, (2) associated injuries, (3) imaging characteristics of computed tomography (CT) scan and magnetic resonance imaging (MRI), (4) surgical procedures, surgical complications, and neurological outcome. RESULTS: All patients were treated as acute spinal injuries and underwent OC fusion on an emergency basis. Patients consisted of 10 males and 2 females with an average age of 47 years (range, 18-82 years). All patients sustained high-energy injuries. Three patients out of 6 patients with normal BAI (basion-axial interval) and BDI (basion-dens interval) values showed visible CCJ injuries on CT scans. However, the remaining 3 patients had no clear evidence of occipitoatlantal instability on CT scans. MRI clearly described several findings indicating occipitoatlantal instability. The 8 patients with normal values of ADI (atlantodens interval interval) demonstrated atlantoaxial instability on CT scan, however, all MRI more clearly and reliably demonstrated C1/2 facet injury and/or cruciate ligament injury. CONCLUSION: We advocate measures to help recognize CCJ injury at an early stage in the present study. Occipitoatlantal instability needs to be carefully investigated on MRI in addition to CT scan with special attention to facet joint and ligament integrity.

Exploring the role of 3-dimensional simulation in surgical training: feedback from a pilot study.

STUDY DESIGN: Randomized control study assessing the efficacy of a pedicle screw insertion simulator. OBJECTIVES: To evaluate the efficacy of an in-house developed 3-dimensional software simulation tool for teaching pedicle screw insertion, to gather feedback about the utility of the simulator, and to help identify the context and role such simulation has in surgical education. SUMMARY OF BACKGROUND DATA: Traditional instruction for pedicle screw insertion technique consists of didactic teaching and limited hands-on training on artificial or cadaveric models before guided supervision within the operating room. Three-dimensional computer simulation can provide a valuable tool for practicing challenging surgical procedures; however, its potential lies in its effective integration into student learning. METHODS: Surgical residents were recruited from 2 sequential years of a spine surgery course. Patient and control groups both received standard training on pedicle screw insertion. The patient group received an additional 1-hour session of training on the simulator using a CT-based 3-dimensional model of their assigned cadaver's spine. Qualitative feedback about the simulator was gathered from the trainees, fellows, and staff surgeons, and all pedicles screws physically inserted into the cadavers during the courses were evaluated through CT. RESULTS: A total of 185 thoracic and lumbar pedicle screws were inserted by 37 trainees. Eighty-two percent of the 28 trainees who responded to the questionnaire and all fellows and staff surgeons felt the simulator to be a beneficial educational tool. However, the 1-hour training session did not yield improved performance in screw placement. CONCLUSIONS: A 3-dimensional computer-based simulation for pedicle screw insertion was integrated into a cadaveric spine surgery instructional course. Overall, the tool was positively regarded by the trainees, fellows, and staff surgeons. However, the limited training with the simulator did not translate into widespread comfort with its operation or into improvement in physical screw placement.

Complete resection and untethering of the cervical and thoracic spinal dermal sinus tracts in adult patients.

Dermal sinus tracts (DSTs) of the cervical and thoracic spine are extremely rare, particularly in adult patients because diagnosis is typically made in the early stage after birth by pediatricians. These cases should be treated surgically as soon as possible to prevent neurological sequelae. This report describes two rare adult cases with cervical and thoracic spine DSTs. The first patient presented with back pain and headache, whose skin lesion had been long known, but disregarded since birth. The second patient had long suffered from residual cervical myelopathy from the prior incomplete surgical treatment. Both cases had these sinus tracts excised completely and had spinal cord untethered successfully without any neurological deterioration. There has been a trend toward earlier diagnosis of these entities, but still some cases that were diagnosed in a delayed fashion or underwent incomplete treatment are reported. Improper management during childhood could lead to irreversible neurological deficit caused by spinal cord tethering and/or direct compression due to DSTs-associated tumors. The early detection and prompt surgical intervention improve the chance of a good surgical outcome. Furthermore, complete excision of the sinus tracts and associated tumors could help prevent future bacterial contamination and recurrence.

Possible Double Crush Syndrome Caused by Iatrogenic Acquired Lumbosacral Epidermoid Tumor and Concomitant Sacral Tarlov Cyst.

We describe a rare case of 42-year-old female who had possible double crush syndrome caused by iatrogenic spinal epidermoid tumor (ET) associated with lumbar puncture as well as concomitant sacral Tarlov cyst in close proximity. She presented with progressive left-sided perianal pain. She had a history of a Caesarean section with lumbar spinal anesthesia. Magnetic resonance imaging (MRI) demonstrated a relatively small intradural extramedullary solid lesion at L5/S1 level and cystic lesion at S2 level. We considered there were two different lesions, such as a tumor and Tarlov cyst; however, we could not rule out the possibility of a single lesion with two different components. Furthermore, there was a distinct compression at more than one locations along the course of the left S2 nerve root and we suspected possible double crush syndrome. We conducted tumor removal and the lesion turned out to be two different pathologies, such as an ET and Tarlov cyst. Both lesions were intraopertively pinching the left S2 nerve root at different sites as expected. The tumor was successfully removed and the cyst wall was imbricated and sutured. We need to take the possibility of ET into consideration if the patient underwent invasive spinal procedure previously. We also have to pay attention to the possibility of double crush syndrome if the nerve root possibly holding the responsibility for symptoms is compressed at two or more sites. This is the first report of possible double crush syndrome caused by acquired spinal tumor and congenital Tarlov cyst.

Epidemiology and Impact of Spinal Cord Injury in the Elderly: Results of a Fifteen-Year Population-Based Cohort Study.

Although experience suggests a shift in the epidemiology of spinal cord injury (SCI) toward an older demographic, population studies are lacking. We aimed to evaluate (1) how the epidemiology and age profile of SCI have changed over time, and (2) how increased age impacts health outcomes up to 15 years post-injury. A population-based cohort study was performed in Ontario including adults diagnosed with traumatic SCI between 2002 and 2017. Older and younger SCI cohorts were created based on an age cutoff of 65 years. An older cohort of uninjured persons was matched to the older SCI cohort based on age, gender, and comorbidity status. Changes in crude incidence were reported as average annual percentage change (AAPC). Survival, readmissions, and costs were compared between the older and younger SCI cohorts as well as the between the older SCI and older matched uninjured cohorts. The incidence of SCI increased among females (AAPC 2.2; 95% confidence interval [CI] 0.1, 4.3), driven by a marked rise (4%/year) among elderly females (AAPC 4.3; 95% CI 0.1, 4.3). Although no change in incidence was detected for males, there was a trend toward increased incidence among older males (AAPC 1.2; 95% CI -1.3, 3.8). There were a higher proportion of cervical, incomplete, and fall-related injuries in the older than in younger SCI cohorts. Being over 65 years of age was associated with a sixfold increased risk of death (hazard ratio [HR] 5.75; 95% CI 4.72, 7.00). In comparison with the older uninjured cohort, the older SCI cohort had double the risk of death (HR 2.23; 95% CI 2.00, 2.50). Older persons with SCI had higher odds of readmission and higher costs. The incidence of SCI among the elderly is increasing, particularly among women. Prevention through fall reduction and education to improve outcomes are needed.

A 96-well culture platform enables longitudinal analyses of engineered human skeletal muscle microtissue strength.

Three-dimensional (3D) in vitro models of human skeletal muscle mimic aspects of native tissue structure and function, thereby providing a promising system for disease modeling, drug discovery or pre-clinical validation, and toxicity testing. Widespread adoption of this research approach is hindered by the lack of easy-to-use platforms that are simple to fabricate and that yield arrays of human skeletal muscle micro-tissues (hMMTs) in culture with reproducible physiological responses that can be assayed non-invasively. Here, we describe a design and methods to generate a reusable mold to fabricate a 96-well platform, referred to as MyoTACTIC, that enables bulk production of 3D hMMTs. All 96-wells and all well features are cast in a single step from the reusable mold. Non-invasive calcium transient and contractile force measurements are performed on hMMTs directly in MyoTACTIC, and unbiased force analysis occurs by a custom automated algorithm, allowing for longitudinal studies of function. Characterizations of MyoTACTIC and resulting hMMTs confirms the capability of the device to support formation of hMMTs that recapitulate biological responses. We show that hMMT contractile force mirrors expected responses to compounds shown by others to decrease (dexamethasone, cerivastatin) or increase (IGF-1) skeletal muscle strength. Since MyoTACTIC supports hMMT long-term culture, we evaluated direct influences of pancreatic cancer chemotherapeutics agents on contraction competent human skeletal muscle myotubes. A single application of a clinically relevant dose of Irinotecan decreased hMMT contractile force generation, while clear effects on myotube atrophy were observed histologically only at a higher dose. This suggests an off-target effect that may contribute to cancer associated muscle wasting, and highlights the value of the MyoTACTIC platform to non-invasively predict modulators of human skeletal muscle function.

In situ tissue pathology from spatially encoded mass spectrometry classifiers visualized in real time through augmented reality.

Integration between a hand-held mass spectrometry desorption probe based on picosecond infrared laser technology (PIRL-MS) and an optical surgical tracking system demonstrates in situ tissue pathology from point-sampled mass spectrometry data. Spatially encoded pathology classifications are displayed at the site of laser sampling as color-coded pixels in an augmented reality video feed of the surgical field of view. This is enabled by two-way communication between surgical navigation and mass spectrometry data analysis platforms through a custom-built interface. Performance of the system was evaluated using murine models of human cancers sampled in situ in the presence of body fluids with a technical pixel error of 1.0 ± 0.2 mm, suggesting a 84% or 92% (excluding one outlier) cancer type classification rate across different molecular models that distinguish cell-lines of each class of breast, brain, head and neck murine models. Further, through end-point immunohistochemical staining for DNA damage, cell death and neuronal viability, spatially encoded PIRL-MS sampling is shown to produce classifiable mass spectral data from living murine brain tissue, with levels of neuronal damage that are comparable to those induced by a surgical scalpel. This highlights the potential of spatially encoded PIRL-MS analysis for in vivo use during neurosurgical applications of cancer type determination or point-sampling in vivo tissue during tumor bed examination to assess cancer removal. The interface developed herein for the analysis and the display of spatially encoded PIRL-MS data can be adapted to other hand-held mass spectrometry analysis probes currently available.