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BACKGROUND AND PURPOSE: Slowly expanding lesions (SELs) are thought to represent a subset of chronic active lesions and have been associated with clinical disability, severity, and disease progression. The purpose of this study was to characterize SELs using advanced magnetic resonance imaging (MRI) measures related to myelin and neurite density on 7 Tesla (T) MRI. METHODS: The study design was retrospective, longitudinal, observational cohort with multiple sclerosis (n = 15). Magnetom 7T scanner was used to acquire magnetization-prepared 2 rapid acquisition gradient echo and advanced MRI including visualization of short transverse relaxation time component (ViSTa) for myelin, quantitative magnetization transfer (qMT) for myelin, and neurite orientation dispersion density imaging (NODDI). SELs were defined as lesions showing ≥12% of growth over 12 months on serial MRI. Comparisons of quantitative measures in SELs and non-SELs were performed at baseline and over time. Statistical analyses included two-sample t-test, analysis of variance, and mixed-effects linear model for MRI metrics between lesion types. RESULTS: A total of 1075 lesions were evaluated. Two hundred twenty-four lesions (21%) were SELs, and 216 (96%) of the SELs were black holes. At baseline, compared to non-SELs, SELs showed significantly lower ViSTa (1.38 vs. 1.53, p < .001) and qMT (2.47 vs. 2.97, p < .001) but not in NODDI measures (p > .27). Longitudinally, only ViSTa showed a greater loss when comparing SEL and non-SEL (p = .03). CONCLUSIONS: SELs have a lower myelin content relative to non-SELs without a difference in neurite measures. SELs showed a longitudinal decrease in apparent myelin water fraction reflecting greater tissue injury.
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BACKGROUND CONTEXT: Lateral approaches for lumbar interbody fusion (LIF) allow for access to the lumbar spine and disk space by passing through a retroperitoneal corridor either pre- or trans-psoas. A contraindication for this approach is the presence of retroperitoneal scarring that may occur from prior surgical intervention in the retroperitoneal space or from inflammatory conditions with fibrotic changes and pose challenges for the mobilization and visualization needed in this approach. However, there is a paucity of evidence on the prevalence of surgical complications following lateral fusion surgery in patients with a history of abdominal surgery. PURPOSE: The primary aim of this study is to describe the association between surgical complications following lateral interbody fusion surgery and prior abdominal surgical. STUDY DESIGN: Retrospective study. PATIENT SAMPLE: Patients over the age of 18 who underwent lateral lumbar interbody fusion at a large, tertiary care center between 2011 and 2019 were included in the study. OUTCOME MEASURES: The primary outcome included medical, surgical, and thigh-related complications either in the intraoperative or 90-day postoperative periods. Additional outcome metrics included readmission rates, length of stay, and operative duration. METHODS: The electronic health records of 250 patients were reviewed for demographic information, surgical data, complications, and readmission following surgery. The association of patient and surgical factors to complication rate was analyzed using multivariable logistic regression. Statistical analysis was performed using R statistical software (R, Vienna, Austria). RESULTS: Of 250 lateral interbody fusion patients, 62.8% had a prior abdominal surgery and 13.8% had a history of colonic disease. The most common perioperative complication was transient thigh or groin pain/sensory changes (n=62, 24.8%). A multivariable logistic regression considering prior abdominal surgery, age, BMI, history of colonic disease, multilevel surgery, and the approach relative to psoas found no significant association between surgical complication rates and colonic disease (OR 0.40, 95% CI 0.02-2.22) or a history of prior abdominal surgeries (OR 0.56, 95% CI 0.20-1.55). Further, the invasiveness of prior abdominal surgeries showed no association with overall spine complication rate, lateral-specific complications, or readmission rates (p>.05). CONCLUSION: Though retroperitoneal scarring is an important consideration for lateral approaches to the lumbar spine, this study found no association between lateral lumbar approach complication rates and prior abdominal surgery. Further study is needed to determine the impact of inflammatory colonic disease on lateral approach spine surgery.
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Spinal cord ischemia (SCI) is an uncommon but serious complication of thoracic endovascular aortic repair (TEVAR). SCI after TEVAR is thought to result from decreased segmental blood supply to an important network of collateral blood flow in the spinal cord. Little is known about the prevalence and optimal treatment of SCI that occurs beyond the periprocedural period. We report a case of delayed SCI in a 67-year-old patient who underwent TEVAR. The patient presented almost two years after TEVAR with acute paraplegia preceded by pre-syncope. The delayed SCI was likely triggered by pre-syncope, a thrombosed endoleak shown on imaging, and the patient's vascular risk factors. Treatments included cerebrospinal fluid (CSF) drainage, mean arterial pressure (MAP) augmentation, and a naloxone infusion, which resulted in moderate recovery in lower extremity motor function. This case highlights the tenuous nature of spinal cord perfusion after TEVAR and that prompt recognition and early treatment of SCI are critical in preventing the progression from ischemia to infarction.
