Effects of passive cycling on cerebrovascular reactivity in acute brain injured patients: A pilot study.

INTRODUCTION: Early mobilization benefits critically ill patients, but concerns persist, especially in neurologic intensive care unit patients with acute brain injuries. This study assesses early mobility's impact on cerebrovascular autoregulation (CA) and systemic hemodynamics. METHODS: This single-center retrospective study focused on adult neurologic intensive care unit patients undergoing passive cycle ergometry. Data were collected from December 2020 to April 2022. Physical therapists conducted sessions using a standardized protocol, monitoring mean arterial blood pressure (MAP) and intracranial pressure (ICP). The Pressure Reactivity Index (PRx) was calculated as a measure of CA. Statistical analysis included mixed models and repeated measures ANOVA. RESULTS: Eleven patients undergoing continuous physiologic monitoring and early mobility were included, primarily with subarachnoid hemorrhage or intracranial hemorrhage. Median time to protocol initiation was 4 days, with two patients discontinuing due to hemodynamic disturbances. Over a total of 11-hours of neuromonitoring data, passive cycling demonstrated a significant reduction in heart rate (HR), MAP, and ICP across different rotations per minute (RPM) settings compared to baseline. No significant alterations in PRx or cerebral perfusion pressure (CPP) were noted at various RPM levels. However, a significant difference in PRx emerged between patients who completed the protocol and those who did not, particularly at 10 RPM. DISCUSSION: This study offers preliminary insights into the impact of early mobility on CA in acute brain injured patients. While passive cycling demonstrates promise in preserving cerebral hemodynamics, its tolerability may not be uniform across all brain-injured patients. These findings highlight the need to determine optimal early mobilization timing and intensity in this population, emphasizing the necessity for larger prospective studies to validate these findings and inform clinical practice. DETAILS: This manuscript complies with all instructions to the authors. All coauthors meet the authorship requirements and have reviewed and approved the contents of the manuscript. The manuscript has not been published totally or partly, accepted for publication, or under editorial review for publication elsewhere. We have no conflicts of interest to disclose. STROBE checklist was reviewed prior to the submission of this paper. The manuscript adheres to ethical guidelines and was approved by Cleveland Clinic's institutional research board for retrospective study. There is no funding to disclose for this study.

A retrospective analysis of perioperative complications of lateral approach lumbar interbody fusion in patients with prior abdominal surgery or a history of colonic inflammatory disease.

BACKGROUND CONTEXT: Lateral approaches for lumbar interbody fusion (LIF) allow for access to the lumbar spine and disc 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.

Longitudinal myelin content measures of slowly expanding lesions using 7T MRI in multiple sclerosis.

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.

Recognition of Significantly Delayed Spinal Cord Ischemia Following Thoracic Endovascular Aortic Repair: A Case Report and Review of the Literature.

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.