Cardiovascular dysfunction following spinal cord injury

Increased Risk of Myocardial Infarction, Heart Failure, and Atrial Fibrillation After Spinal Cord Injury

BACKGROUND

Heart diseases are a growing concern for the spinal cord injury (SCI) population.

OBJECTIVES

This study aims to compare the incidence of heart diseases between SCI survivors and the general non-SCI population.

METHODS

We identified 5,083 SCI survivors and 1:3 age- and sex-matched non-SCI controls. Study outcomes were myocardial infarction (MI), heart failure (HF), and atrial fibrillation (AF). The cohort was followed up from the index date (diagnosis date for SCI or corresponding date for matched controls) until 2019.

RESULTS

SCI survivors showed a higher risk for MI (adjusted HR [aHR]: 2.41; 95% CI: 1.93-3.00), HF (aHR: 2.24; 95% CI: 1.95-2.56), and AF (aHR: 1.84; 95% CI: 1.49-2.28) compared to controls. The risks were further increased for those who were registered in the National Disability Registry within 1 year from the index date (SCI survivors with disability): SCI survivors with severe disability had the highest risks of MI (aHR: 3.74; 95% CI: 2.43-5.76), HF (aHR: 3.96; 95% CI: 3.05-5.14), and AF (aHR: 3.32; 95% CI: 2.18-5.05). Cervical and lumbar SCI survivors had an increased risk of heart disease regardless of disability compared to matched controls; these risks were slightly higher in those with disability. Thoracic SCI survivors with disability had significantly increased risk of heart disease compared to matched controls.

CONCLUSIONS

SCI survivors at all levels were at significantly greater risk for heart disease than non-SCI controls, particularly those with severe disability. Clinicians must be aware of the importance of heart disease in SCI survivors.

Treatment of postprandial hypotension with acarbose in an adult with cervical spinal cord injury: a case report

INTRODUCTION

Postprandial hypotension is a type of autonomic dysfunction where there is a decrease in systolic blood pressure of >20 mm HG within 2 h after eating thought to be due to poor cardiovascular compensation for splanchnic blood pooling that occurs with meals. This form of autonomic dysfunction is underdiagnosed in patients with spinal cord injury, likely in part because it can be asymptomatic.

CASE PRESENTATION

26-year-old with complete cervical spinal cord injury (SCI) presented with neck pain described as severe 10/10 pain, which felt like "a rope around his neck." Pain came on during and after meals and was associated with a feeling of pressure behind his eyes, white spots in his vision along with feeling as if he was going to pass out. The caregiver noted a systolic blood pressure drop by about 30-40 points with meals and lost weight due to avoiding eating. A diagnosis of post-prandial hypotension (PPH) was made and Acarbose was started at a low dose 25 mg three times per day with meals. During follow up, the patient reported complete resolution of drops of blood pressure, neck pain, and all associated symptoms. The patient was able to eat comfortably and gained weight.

DISCUSSION

There are few case reports on PPH in SCI and none looking at acarbose on a young, nondiabetic person with SCI. Clinicians should be aware that PPH can occur in young otherwise healthy people with SCI. Further research is needed on PPH, including the use of acarbose, in the SCI population.

Estimation of peak oxygen consumption in individuals with spinal cord injury patients using multiple linear regression analysis: a preliminary study

PURPOSE

This study aims to develop a regression model to estimate peak oxygen consumption (VO2peak) in individuals with spinal cord injury (SCI) by employing different variables.

METHODS

In this study, 34 participants were divided into two groups: 19 with cervical injury (CI) and 15 with thoracic injury (TI). Key measurements included VO2peak and related factors such as age, height, weight, body mass index (BMI), fat-free mass, body fat percentage, limb and trunk circumferences, spinal cord independence (SCIM III), Korean activities of daily living (K-ADL), and respiratory functions (forced vital capacity (FVC), peak expiratory flow (PEF), and maximum voluntary ventilation (MVV)). Statistical analyses were conducted using forward selection regression to examine the relationships between these variables.

RESULTS

Height, calf circumference, SCIM III score, and PEF were key variables in all patients with SCI (TSCI). For patients with CI, the key variables were height, calf circumference, and MVV, whereas for patients with TI, the key variable was calf circumference. The average explanatory powers of the VO2peak regression model for TSCI were 70.3% (R2) and 66.2% (adjusted R2), with an average standard error of estimate (SEE) of 2.94 ml/kg/min. The average explanatory power for patients with CI was 71.7% (R2) and 66.1% (adjusted R2), with an average SEE of 1.88 ml/kg/min. The average explanatory power for patients with TI was 55.9% (R2) and 52.5% (adjusted R2), with an average SEE of 3.41 ml/kg/min. There was no significant difference between the VO2peak measured and predicted VO2peak for each type of injury.

CONCLUSION

The regression model for estimating VO2peak in SCI patients in this preliminary study is as follows: TSCI=39.684-0.144×(Height)-0.513×(Calf)+0.136×(SCIM III)+1.187×(PEF), CI=38.842-0 .158×(Height) - 0.371×(Calf)+0.093×(MVV), TI=42.325-0.813×(Calf).

A Fast-Track Respiratory Protocol for High Cervical Spine Injury: A Case Report

BACKGROUND

Cervical spinal cord injury can greatly affect pulmonary function, resulting in complications, including respiratory failure with prolonged mechanical ventilation, ultimately leading to increased mortality and high health care costs. Weaning from mechanical ventilation is particularly challenging in patients with complete high spinal cord injury.

CASE PRESENTATION

We present the case of a 42-year-old man who suffered a complete cervical 5-6 spinal cord injury following a rollover motor vehicle crash and subsequently developed postoperative pneumonia and severe hypoxemic respiratory failure. He received a novel approach to fast-track respiratory care, including early and aggressive secretion clearance management, moderate pressure level of airway pressure release ventilation, timely transition to spontaneous mode, early tracheostomy and humane care, and high-flow oxygenation via tracheotomy after weaning off the ventilator. As a result, the patient experienced significant improvement in pulmonary function and was successfully liberated from the ventilator within a 2-week period.

CONCLUSION

This case highlights the potential effectiveness of fast-track respiratory care in promoting lung function restoration and expediting liberation from mechanical ventilation in patients with severe hypoxemic respiratory failure following a complete cervical spinal cord injury. However, further research is warranted to validate these findings and expand our understanding in this area.

Is it safe to initiate activity-based therapy within days following traumatic spinal cord injury? Preliminary results from the PROMPT-SCI trial

CONTEXT

Activity-based therapy initiated within days of the accident could prevent complications and improve neurofunctional outcomes in patients with traumatic spinal cord injury (TSCI). However, it has never been attempted in humans with TSCI because of practical obstacles and potential safety concerns. The PROMPT-SCI trial is the first attempt at implementing ABT within the first days following a TSCI (i.e. very early ABT; VE-ABT). The objective is to determine if VE-ABT can be initiated safely in the intensive care unit (ICU) within 48 h of early decompressive surgery.

DESIGN

As part of the PROMPT-SCI trial, 15 adult patients with severe TSCI were enrolled between April and November of 2021. The intervention consisted of 30-minute sessions of motor-assisted in-bed leg cycling starting within 48 h of early spinal surgery. Safety was assessed through continuous monitoring of vital signs and recording of adverse events during and after sessions. The main outcome measure was the achievement (yes or no) of a full and safe session within 48 h of early surgery.

FINDINGS

Out of the 15 participants, 10 (66.6%) achieved this outcome. Out of the remaining 5, 2 were not cleared to engage in cycling within 48 h of surgery and 3 initiated cycling within 48 h but stopped prematurely. All 5 eventually completed a full and safe session within the next 1-2 days. In all 15 participants, there were no neurological deteriorations after the first completed session.

CONCLUSION

Our results suggest that it is safe and feasible to perform a first session of VE-ABT within days of a severe TSCI with no serious adverse events and excellent completion rates.

The neurovascular unit in healthy and injured spinal cord

The neurovascular unit (NVU) reflects the close temporal and spatial link between neurons and blood vessels. However, the understanding of the NVU in the spinal cord is far from clear and largely based on generalized knowledge obtained from the brain. Herein, we review the present knowledge of the NVU and highlight candidate approaches to investigate the NVU, particularly focusing on the spinal cord. Several unique features maintain the highly regulated microenvironment in the NVU. Autoregulation and neurovascular coupling ensure regional blood flow meets the metabolic demand according to the blood supply or local neural activation. The blood-central nervous system barrier partitions the circulating blood from neural parenchyma and facilitates the selective exchange of substances. Furthermore, we discuss spinal cord injury (SCI) as a common injury from the perspective of NVU dysfunction. Hopefully, this review will help expand the understanding of the NVU in the spinal cord and inspire new insights into SCI.

Unusual presentation of acute spinal cord injury with ischaemic electrocardiographic changes: a case report

Background

Spinal cord injury (SCI) is a significant cause of morbidity and mortality with an incidence of 40-83/million/year. Sympathetic denervation in SCI leads to cardiovascular abnormalities including orthostatic hypotension, rhythm disturbance, and repolarization changes. Electrocardiographic (ECG) findings include bradyarrhythmias, ectopic beats, long QT interval, and ST-T changes that may be mistaken for myocardial ischaemia.

Case summary

A patient in their 40 s with free past medical history was referred to our centre with the diagnosis of non-ST elevation acute coronary syndrome. On presentation, chest pain was diffuse and radiating to the back. Twelve-lead ECG showed deep symmetrical T-wave inversion. Echocardiography and cardiac troponin were normal. The patient was scheduled for multi-slice computed tomography coronary angiography which was normal; however, a few hours after admission, the patient developed rapidly progressive motor weakness in both lower limbs with urine retention. Examination revealed motor power Grade 1 in both lower limbs. All sensations were diminished with a sensory level at T6. Urgent magnetic resonance imaging spine revealed neoplastic infiltration of the whole vertebrae with D5/D6 fracture exerting spinal cord compression. The patient was referred for urgent decompression surgery.

Conclusion

Electrocardiographic changes could be the earliest sign for ongoing SCI. ST-elevation is reported in higher levels of complete injury, while ST depression and inverted T waves can occur independent of lesion level or severity. Misinterpretation of these changes may cause a delay in reaching the correct diagnosis. We highlight the importance of considering neurological causes for ischaemic-like ECG changes, as early recognition could prevent irreversible functional loss.

Unexpected Bradycardia Related to Surgical Manipulation During Thoracolumbar Spinal Surgery

BACKGROUND

Although spinal surgery can offer pain relief and functional improvements in daily life, it is often associated with various perioperative complications. The incidence of cardiac complications associated with spinal surgery is relatively low. We evaluated frequency and causes for bradycardia incidents in posterior thorocolumbar spinal surgeries.

METHODS

We retrospectively evaluated posterior thoracolumbar spinal surgeries between 2018-2022 for bradycardic events in our tertiary general hospital. Patients operated for degenerative changes or disk herniations are included, other cases for tumors, trauma, arteriovenous (AV) fistulae or previously operated are excluded.

RESULTS

The study reached 6 eligible patients (4 female and 2 male) aged between 45-75 years (mean: 63.3) among 550 patients operated between 2018-2022. The rate of bradycardia was 1.09%. Of these, 5 patients (lumbar discectomy: one; posterior stabilization:4) exhibited it following L2 and L3 root manipulation and one presented it following L4-5 discectomy. In each of these cases, bradycardia occurred during surgical manipulation and ceased upon removal of the insult. None of the cases exhibited accompanying hypotension. The patient's heart rates were seen to drop to lowest the of 30 beats/min, and all patients exhibited favorable outcomes and no postoperative cardiac complications over a mean follow-up period of 20 months (range: 10-40 months).

CONCLUSIONS

The current study examines the occurrence of unexpected bradycardia events associated with thoracolumbar spinal surgery during surgical handling of the dura mater. Awareness of such incidents among surgeons and anesthesiologists can help prevent catastrophic outcomes caused by adverse cardiac events.

At the heart of the matter: how mental stress and negative emotions affect atrial fibrillation

Atrial fibrillation (AF) is the most common form of cardiac arrhythmia, affecting 2%-3% of the world's population. Mental and emotional stress, as well as some mental health conditions (e.g., depression) have been shown to significantly impact the heart and have been suggested to act both as independent risk factors and triggers in the onset of AF. In this paper, we review the current literature to examine the role that mental and emotional stress have in the onset of AF and summarise the current knowledge on the interaction between the brain and heart, and the cortical and subcortical pathways involved in the response to stress. Review of the evidence suggests that mental and emotional stress negatively affect the cardiac system, potentially increasing the risk for developing and/or triggering AF. Further studies are required to further understand the cortical and sub-cortical structures involved in the mental stress response and how these interact with the cardiac system, which may help in defining new strategies and interventions to prevent the development of, and improve the management of AF.

Negative Chronotropic Cardiovascular Changes in Lumbar Spine Surgery: A Potential Spinal-Cardiac Reflex?

Cardiovascular changes following lumbar spine surgery in a prone position are exceedingly rare. Over the past 20 years, a total of six cases have been published where patients experienced varying degrees of bradycardia, hypotension, and asystole, which could be attributed to intraoperative dural manipulation. As such, there is emerging evidence for a potential neural-mediated spinal-cardiac reflex. The authors report their experience of negative chronotropy during an elective lumbar spine surgery that coincided with dural manipulation and review the available literature. A 34-year-old male presented with a long-standing history of lower back pain recently deteriorating to bilaterally radiating leg pain, with restricted left leg raise, and numbness at the left L5 dermatomal territory. The patient was an athletic police officer with no comorbidities or past medical history. Magnetic resonance imaging lumbosacral spine revealed spinal stenosis most pronounced at L4/L5 and disc bulges at L3/L4 and L5/S1. The patient opted for lumbar decompression surgery. After an unremarkable comprehensive preoperative workup, including cardiac evaluation (electrocardiogram, echocardiogram), the patient was induced general anesthesia in a prone position. A lumbar incision was made from L2 to S1. When the left L4 nerve root was retracted while removing the prolapsed disc at L4/L5, the anesthetist cautioned the surgeon of bradycardia (34 beats per minute [bpm]), and the surgery was immediately stopped. The heart rate improved to 60 bpm within 30 seconds. When the root was later retracted again, a second episode of bradycardia occurred for 4 minutes with heart rate declining to 48 bpm. The surgery was stopped, and after 4 minutes, the anesthetist administered 600 µg of atropine. The heart rate then rose to 73 bpm within 1 minute. Other potential causes for bradycardia were excluded. The total blood loss was estimated to be 100 mL. He remains well at his 6-month follow-up and has returned to work as normal. Akin to previously published cases, each episode of bradycardia coincided with dural manipulation, which may indicate a possible reflex between the spinal dura mater and the cardiovascular system. Such a rare adverse event may occur even in seemingly healthy, young individuals, and anesthetists should caution the operating surgeon of bradycardias to exclude operative manipulation of the dura as the cause. While this phenomenon is only reported in a handful of lumbar spine surgery cases, it provides evidence for a potential spinal-cardiac physiological reflex in the lumbar spine that may be neural mediated and should be investigated further.

Optimizing spinal cord injury in zebrafish larvae: effects of age on the injury response

Zebrafish are an increasingly popular model to study spinal cord injury (SCI) regeneration. The transparency of larval zebrafish makes them ideal to study cellular processes in real time. Standardized approaches, including age of injury, are not readily available making comparisons of the results with other models challenging. In this study, we systematically examined the response to spinal cord transection of larval zebrafish at three different ages (3-7 days post fertilization or dpf) to determine whether the developmental complexity of the central nervous system affects the overall response to SCI. We then used imaging and behavioral analysis to evaluate whether differences existed based on the age of injury. All ages of larval zebrafish upregulated the required genes for glial bridge formation, ctgfa and gfap, at the site of injury, consistent with studies from adult zebrafish. Though all larval ages upregulated factors required to promote glial bridging, young larval zebrafish (3 dpf) were better able to regenerate axons independent of the glial bridge, unlike older zebrafish (7 dpf). Consistent with this data, locomotor experiments demonstrated that some swimming behavior occurs independent of glial bridge formation, further highlighting the need for standardization of this model and recovery assays. Overall, we found subtle cellular differences based on the age of transection in zebrafish, underlining the importance of considering age when designing experiments aimed at understanding regeneration.

The Prevalence of Cardiovascular Diseases in Paralympic Athletes

Paralympic participants represent a special subset of athletes. Although sudden cardiac death in this group is a rare event, it should be underlined that, in particular, Paralympians with movement restrictions have a higher prevalence of coronary heart disease. Numerous reports have focused on comparing athletes with spinal cord injury (SCI) and the ones with non-spinal cord injury—NSCI. The first group is more prone to develop arrhythmias, arterial hypertension, hyperlipidaemia including atrial fibrillation and atrial flutter, and this group potentially may have a higher risk of cardiovascular mortality. In ECGs of the disabled athletes with SCI, we more often find changes typically established as consequences of exercise training, such as T-wave inversions. The potential differences in the cardiovascular status of disabled athletes may depend not only on the class of impairment, but also on the discipline of sport and environmental conditions, which makes the analysis relatively complex. The paper analyses up-to-date articles discussing the cardiovascular problems in disabled athletes, pointing to scarce data in several fields of interest. Previous studies on the frequency of abnormalities of the cardiovascular system in Paralympic athletes highlighted the need to intensify preventive cardiology care for this group of athletes, and some activities could be proposed for sportsmen and sportswomen in this group, including more frequent screening ECG, application of 24 h ECG Holter monitoring, echocardiography and cardiological care. Due to the relatively few data available and existing discrepancies in this area, further research is necessary.

Consequences of spinal cord injury on the sympathetic nervous system

Spinal cord injury (SCI) damages multiple structures at the lesion site, including ascending, descending, and propriospinal axons; interrupting the conduction of information up and down the spinal cord. Additionally, axons associated with the autonomic nervous system that control involuntary physiological functions course through the spinal cord. Moreover, sympathetic, and parasympathetic preganglionic neurons reside in the spinal cord. Thus, depending on the level of an SCI, autonomic function can be greatly impacted by the trauma resulting in dysfunction of various organs. For example, SCI can lead to dysregulation of a variety of organs, such as the pineal gland, the heart and vasculature, lungs, spleen, kidneys, and bladder. Indeed, it is becoming more apparent that many disorders that negatively affect quality-of-life for SCI individuals have a basis in dysregulation of the sympathetic nervous system. Here, we will review how SCI impacts the sympathetic nervous system and how that negatively impacts target organs that receive sympathetic innervation. A deeper understanding of this may offer potential therapeutic insight into how to improve health and quality-of-life for those living with SCI.

Initial Heart Rate Predicts Functional Independence in Patients With Spinal Cord Injury Requiring Surgery: A Registry-Based Study in a Mature Trauma System Over the Past 10 Years

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

To determine the ability of early vital sign abnormalities to predict functional independence in patients with SCI that required surgery.

METHODS

A retrospective analysis of data extracted from the Pennsylvania Trauma Outcome Study database. Inclusion criteria were patients >18 years with a diagnosis of SCI who required urgent spine surgery in Pennsylvania from 1/1/2010-12/31/2020 and had complete records available.

RESULTS

A total of 644 patients met the inclusion criteria. The mean age was 47.1 ± 14.9 years old and the mean injury severity score (ISS) was 22.3 ± 12.7 with the SCI occurring in the cervical, thoracic, and lumbar spine in 61.8%, 19.6% and 18.0%, respectively. Multivariable logistic regression analyses for predictors of functional independence at discharge showed that higher HR at the scene (OR 1.016, 95% CI 1.006-1.027, P = .002) and lower ISS score (OR .894, 95% CI .870-.920, P < .001) were significant predictors of functional independence. Similarly, higher admission HR (OR 1.015, 95% CI 1.004-1.027, P = .008) and lower ISS score (OR .880, 95% CI 0.864-.914, P < .001) were significant predictors of functional independence. Peak Youden indices showed that patients with HR at scene >70 and admission HR ≥83 were more likely to achieve functional independence.

CONCLUSIONS

Early heart rate is a strong predictor of functional independence in patients with SCI. HR at scene >70 and admission HR ≥83 is associated with improved outcomes, suggesting lack of neurogenic shock.

Altered heart rate variability and pulse-wave velocity after spinal cord injury

BACKGROUND

Heart rate variability (HRV) and pulse-wave velocity (PWV), indicators of cardiac function, are altered in patients with spinal cord injury (SCI), suggesting that autonomic cardiac function and arterial stiffness may underlie the high risk of cardiovascular complications in these patients. No study has simultaneously investigated HRV and PWV in the same patients.

AIM

To evaluate cardiovascular complications in SCI patients by comparing HRV and PWV between patients with and without SCI.

METHODS

In this cross-sectional pilot study, patients with (n = 60) and without SCI (n = 60) were recruited from December 7, 2019 to January 21, 2020. Each participant received a five-minute assessment of HRV and the cardiovascular system using the Medicore HRV Analyzer SA-3000P. Differences in HRV and PWV parameters between participants with and without SCI were statistically examined.

RESULTS

We observed a significant difference between participants with and without SCI with respect to the standard deviation of all normal-to-normal intervals, square root of the mean sum of squared successive risk ratio interval differences, physical stress index, total power, very-low frequency, low frequency, high frequency, and arterial elasticity.

CONCLUSION

Patients with SCI have weaker sympathetic and parasympathetic activity as well as lower arterial elasticity compared to those without, suggesting that SCI may increase cardiac function loading.

Maladaptation of Renal Hemodynamics Contributes to Kidney Dysfunction Resulting from Thoracic Spinal Cord Injury in Mice

Renal dysfunction is a hallmark of spinal cord injury (SCI). Several SCI sequalae are implicated, however, the exact pathogenic mechanism of renal dysfunction is unclear. Herein, we found that T3 (T3Tx) or T10 (T10Tx) complete thoracic spinal cord transection induced hypotension, bradycardia, and hypothermia immediately after injury. T3Tx-induced hypotension but not bradycardia or hypothermia slowly recovered to levels in T10Tx SCI and uninjured mice ~16 h after injury as determined by continuous radiotelemetry monitoring. Both types of thoracic SCI led to a marked decrease in albuminuria and proteinuria in all phases of SCI, while the kidney injury marker, NGAL, rapidly increased in the acute phase, remaining elevated in the chronic phase of T3Tx SCI. Renal interstitial and vascular elastin fragmentation after SCI were worsened during chronic T3Tx SCI. In the chronic phase, renal vascular resistance response to a step increase in renal perfusion pressure or a bolus injection of Ang II or NE was almost completely abolished after T3Tx SCI. Bulk RNAseq analysis showed enrichment of genes involved in extracellular matrix (ECM) remodeling and chemokine signaling in the kidney from T3Tx SCI mice. Serum levels of interleukin 6 was elevated in the acute but not chronic phase of T3Tx and T10Tx SCI, while serum amyloid A1 level was elevated in both acute and chronic phases. We conclude that tissue fibrosis and hemodynamic impairment are involved in renal dysfunction resulting from thoracic SCI; these pathological alterations, exacerbated by high thoracic-level injury, is mediated at least partly by renal microvascular ECM remodeling.

Autonomic Dysreflexia following Spinal Cord Injury

Autonomic dysreflexia (AD) is a potentially life-threatening condition of the autonomic nervous system following spinal cord injury at or above T6. One of the most common symptoms is a sudden increase in blood pressure induced by afferent sensory stimulation owing to unmodulated reflex sympathetic hyperactivity. Such episodes of high blood pressure might be associated with a high risk of cerebral or retinal hemorrhage, seizures, heart failure, or pulmonary edema. In-depth knowledge is, therefore, crucial for the proper management of the AD, especially for spine surgeons, who encounter these patients quite often in their clinical practice. Systematical review of the literature dealing with strategies to prevent and manage this challenging condition was done by two independent reviewers. Studies that failed to assess primary (prevention, treatment strategies and management) and secondary outcomes (clinical symptomatology, presentation) were excluded. A bibliographical search revealed 85 eligible studies that provide a variety of preventive and treatment measures for the subjects affected by AD. As these measures are predominantly based on noncontrolled trials, long-term prospectively controlled multicenter studies are warranted to validate these preventive and therapeutic proposals.

Comparison of disc and wire electrodes to restore cough via lower thoracic spinal cord stimulation

OBJECTIVE

To compare the safety and effectiveness of wire (WE) vs. disc (DE) electrodes to restore cough in subjects with spinal cord injury (SCI).

DESIGN

Clinical trials assessing the effectiveness and clinical outcomes associated with two electrode systems to activate the expiratory muscles.

SETTING

Inpatient hospital setting for DE or WE electrode insertion; outpatient evaluation of cough efficacy and instructions for home use.

PARTICIPANTS

Twenty-nine subjects with SCI; 17 participants with DE and 12 with WE implants.

INTERVENTION

Surgical implantation of WE or DE to restore cough. Daily application of spinal cord stimulation (SCS) at home.

MAIN OUTCOME MEASURE(S)

Airway pressure (P) and peak airflow (F) generation achieved with SCS; clinical parameters including ease in raising secretions, incidence of acute respiratory tract infections (RTI) and side effects.

RESULTS

P and F achieved with DE and WE were not significantly different. For example, at total lung capacity (TLC) with participant effort, P was 128 ± 12 cmH2O and 118 ± 14 cmH2O, with DE and WE, respectively. The degree of difficulty in raising secretions improved markedly in both groups. The incidence of RTI per year fell from 1.3 ± 0.3 and 1.3 ± 0.5-0.3 ± 0.1 and 0.1 ± 0.1 for DE and WE groups, respectively (P < 0.01 for both when compared to pre-implant values and NS between DE and WE groups). The only significant side effect i.e. short-term autonomic dysreflexia was also similar between groups.

CONCLUSIONS

The results of this investigation indicate that both DE and WE result in comparable degrees of expiratory muscle activation, clinical benefits and side effects. Importantly, SCS to restore cough can be achieved with use of WE which can be placed using minimally invasive techniques and associated reduction in cost, surgical time and overall risk.Trial registration: ClinicalTrials.gov identifier: NCT00116337., NCT01659541, FDA IDE: G980267.

Therapeutic acute intermittent hypoxia: A translational roadmap for spinal cord injury and neuromuscular disease

We review progress towards greater mechanistic understanding and clinical translation of a strategy to improve respiratory and non-respiratory motor function in people with neuromuscular disorders, therapeutic acute intermittent hypoxia (tAIH). In 2016 and 2020, workshops to create and update a "road map to clinical translation" were held to help guide future research and development of tAIH to restore movement in people living with chronic, incomplete spinal cord injuries. After briefly discussing the pioneering, non-targeted basic research inspiring this novel therapeutic approach, we then summarize workshop recommendations, emphasizing critical knowledge gaps, priorities for future research effort, and steps needed to accelerate progress as we evaluate the potential of tAIH for routine clinical use. Highlighted areas include: 1) greater mechanistic understanding, particularly in non-respiratory motor systems; 2) optimization of tAIH protocols to maximize benefits; 3) identification of combinatorial treatments that amplify plasticity or remove plasticity constraints, including task-specific training; 4) identification of biomarkers for individuals most/least likely to benefit from tAIH; 5) assessment of long-term tAIH safety; and 6) development of a simple, safe and effective device to administer tAIH in clinical and home settings. Finally, we update ongoing clinical trials and recent investigations of tAIH in SCI and other clinical disorders that compromise motor function, including ALS, multiple sclerosis, and stroke.

Noninvasive spinal stimulation safely enables upright posture in children with spinal cord injury

In children with spinal cord injury (SCI), scoliosis due to trunk muscle paralysis frequently requires surgical treatment. Transcutaneous spinal stimulation enables trunk stability in adults with SCI and may pose a non-invasive preventative therapeutic alternative. This non-randomized, non-blinded pilot clinical trial (NCT03975634) determined the safety and efficacy of transcutaneous spinal stimulation to enable upright sitting posture in 8 children with trunk control impairment due to acquired SCI using within-subject repeated measures study design. Primary safety and efficacy outcomes (pain, hemodynamics stability, skin irritation, trunk kinematics) and secondary outcomes (center of pressure displacement, compliance rate) were assessed within the pre-specified endpoints. One participant did not complete the study due to pain with stimulation on the first day. One episode of autonomic dysreflexia during stimulation was recorded. Following hemodynamic normalization, the participant completed the study. Overall, spinal stimulation was well-tolerated and enabled upright sitting posture in 7 out of the 8 participants.

Scoliosis due to trunk muscle paralysis frequently requires surgical treatment in children with spinal cord injury. The authors demonstrate the safety and efficacy of transcutaneous spinal stimulation to enable upright sitting posture in 7/8 children with trunk control impairment in a within-subjects, repeated measures pilot clinical trial.

Cervical spinal injury compromises caudal spinal tissue oxygenation and undermines acute intermittent hypoxia-induced phrenic long-term facilitation

An important model of respiratory motor plasticity is phrenic long-term facilitation (pLTF), a persistent increase in phrenic burst amplitude following acute intermittent hypoxia (AIH). Moderate AIH elicits pLTF by a serotonin-dependent mechanism known as the Q pathway to phrenic motor facilitation. In contrast, severe AIH (greater hypoxemia) increases spinal adenosine accumulation and activates phrenic motor neuron adenosine 2A receptors, thereby initiating a distinct mechanism of plasticity known as the S pathway. Since the Q and S pathways interact via mutual cross-talk inhibition, the balance between spinal serotonin release and adenosine accumulation is an important pLTF regulator. Spinal injury decreases spinal tissue oxygen pressure (PtO₂) caudal to injury. Since AIH is being explored as a neurotherapeutic to restore breathing ability after cervical spinal injury, we tested the hypothesis that decreased PtO₂ in the phrenic motor nucleus after C2 spinal hemisection (C2Hx) undermines moderate AIH-induced pLTF, likely due to shifts in the adenosine/serotonin balance. We recorded C3/4 ventral cervical PtO₂ with an optode, and bilateral phrenic nerve activity in anesthetized, paralyzed and ventilated rats, with and without C2Hx. In intact rats, PtO₂ was lower during severe versus moderate AIH as expected. In chronic C2Hx rats (> 8 weeks post-injury), PtO₂ was lower during baseline and moderate hypoxic episodes, approaching severe AIH levels in intact rats. After C2Hx, pLTF was blunted ipsilateral, but observed contralateral to injury. We conclude that C2Hx compromises PtO₂ near the phrenic motor nucleus and undermines pLTF, presumably due to a shift in the serotonin versus adenosine balance during hypoxic episodes. These findings have important implications for optimizing AIH protocols in our efforts to restore breathing ability with therapeutic AIH in people with chronic cervical spinal injury.

Physiologic and Clinical Features of the Paralympic Athlete's Heart

Importance

Paralympic medicine is a newly adopted term to describe the varied health care issues associated with athletes in the Paralympics. Scarce scientific data, however, are currently available describing the cardiac remodeling in Paralympic athletes.

Objective

To investigate the physiological and clinical characteristics of the Paralympic athlete's heart and derive the normative values.

Design, Setting, and Participants

This is a single-center study on a relatively large cohort of Paralympic athletes, conducted at the Italian Institute of Sport Medicine and Science. Paralympic athletes free of cardiac or systemic pathologic conditions other than their cause of disability were selected for participation in the Paralympic Games from January 2000 to June 2014. Athletes were arbitrarily classified for disability in 2 groups: those with spinal cord injuries (SCI) and those with non-SCI (NSCI). Data analysis occurred from March 2019 to June 2020.

Main Outcomes and Measures

The primary outcome was the difference in cardiac remodeling in Paralympic athletes according to disability type and sports discipline type. Athletes underwent cardiac evaluation, including 12-lead and exercise electrocardiograms, echocardiography, and cardiopulmonary exercise testing.

Results

Among 252 consecutive Paralympic athletes (median [interquartile range (IQR)] age, 34 [29-41] years; 188 men [74.6%]), 110 had SCI and 142 had NSCI. Those with SCI showed a higher prevalence of abnormal electrocardiogram findings than those with NSCI (13 of 110 [11.8%] vs 6 of 142 [4.2%]; P = .003), smaller left ventricular end-diastolic dimension (median [IQR], 48 [46-52] vs 51 [48-54] mm; P = .001) and left ventricular mass index (median [IQR], 80.6 [69-94] vs 91.3 [80-108] g/m2; P = .001), and lower peak oxygen uptake (VO2) (median [IQR], 27.1 [2-34] vs 38.5 [30-47] mL/min/kg; P = .001) in comparison with those with NSCI. Regarding sport discipline, endurance athletes had a larger left ventricular cavity (median [IQR], 52 [47-54] vs 49 [47-53] mm; P = .006) and higher peak VO2 (median [IQR], 46 [39-55] vs 30 [25-35] mL/min/kg; P = .001) than athletes in nonendurance sports.

Conclusions and Relevance

Cardiac remodeling in Paralympic athletes differed by disability and sport discipline. Having NSCI lesions and engaging in endurance sports were associated with the largest left ventricular cavity and left ventricular mass and highest VO2 peak. Having SCI lesions and engaging in nonendurance disciplines, on the contrary, were associated with the smallest left ventricular cavity and mass and lowest VO2 peak.

Effects of 16-Form Wheelchair Tai Chi on the Autonomic Nervous System among Patients with Spinal Cord Injury

Objective

This study aims to investigate the effects of 16-form Wheelchair Tai Chi (WCTC16) on the autonomic nervous system among patients with spinal cord injury (SCI).

Methods

Twenty patients with chronic complete thoracic SCI were recruited. Equivital life monitoring system was used to record and analyze heart rate variability (HRV) of patients for five minutes before and after five consecutive sets of WCTC16, respectively. The analysis of HRV in the time domain included RR intervals, the standard deviation of all normal RR intervals (SDNN), and the root mean square of the differences between adjacent NN intervals (RMSSD). The analysis of HRV in the frequency domain included total power (TP), which could be divided into very-low-frequency area (VLFP), low-frequency area (LFP), and high-frequency area (HFP). The LF/HF ratio as well as the normalized units of LFP (LFPnu) and HFP (HFPnu) reflected the sympathovagal balance.

Results

There was no significant difference in RR interval, SDNN, RMSSD, TP, HEP, VLFP, and LFP of SCI patients before and after WCTC16 exercise (P > 0.05). LFPnu and HF peak decreased, while HFPnu and LF/HF increased in SCI patients after WCTC16 exercise. The differences were statistically significant (P < 0.001).

Conclusion

WCTC16 can enhance vagal activity and decrease sympathetic activity so that patients with chronic complete thoracic SCI can achieve the balanced sympathovagal tone.

Influence of mid and low paraplegia on cardiorespiratory fitness and energy expenditure

STUDY DESIGN

Observational, Cross-sectional.

OBJECTIVE

Examine the influence of mid (MP) and low (LP) paraplegia on cardiorespiratory fitness (CRF), energy expenditure (EE), and physical activity levels (PAL), and compare these data to able-bodied (AB) individuals.

SETTING

Academic medical center.

METHODS

Persons with MP (n = 6, T6-T8, 83% male, age: 31 ± 11 y, BMI: 24 ± 7 kg/m²) and LP (n = 5; T10-L1, 100% male, age: 39 ± 11 y, BMI: 26 ± 5 kg/m²) and AB controls (n = 6; 67% male, age: 29 ± 12 y, BMI: 26 ± 5 kg/m²) participated. All participants underwent 45-min of arm-crank exercise where CRF and exercise EE were measured. Basal metabolic rate (BMR) was measured, and total daily EE (TDEE) and PAL were estimated.

RESULTS

Absolute VO_2Peak (MP: 1.6 ± 0.2, LP: 1.9 ± 0.1, AB: 2.5 ± 0.7 l/min), peak metabolic equivalents (MP: 6.8 ± 1.3, LP: 5.7 ± 0.7, AB: 8.8 ± 0.8 METs), peak power output (MP: 72.9 ± 11.5, LP: 86.8 ± 6.1, AB: 121.0 ± 34.8 Watts), and maximal heart rate (MP: 177.7 ± 9.8, LP: 157 ± 13.6, AB: 185.2 ± 8.5 bpm) were significantly different between the three groups (p < 0.05). BMR and TDEE did not significantly differ between the three groups (p > 0.05), whereas exercise EE (MP: 7.8 ± 1.2, LP: 9.5 ± 0.7, AB: 12.4 ± 3.5 kcal/min) and PAL (MP: 1.30 ± 0.04, LP: 1.32 ± 0.04, AB: 1.43 ± 0.06) significantly differed (p < 0.05). In the AB group, 33.3% and 66.7% were classified as sedentary or having low activity levels, respectively, while all persons with paraplegia were classified as sedentary according to PAL classifications.

CONCLUSION

Individuals with MP and LP have lower CRF, exercise EE, and PALs compared to AB individuals.

Topical Systematic and Synthetic Literature Review Regarding Men Sexual Dysfunctions after Spinal Cord Injury

Introduction Spinal cord injury (SCI) is a life-altering event usually associated with loss of motor and sensory, as well as with bladder, bowel and sexual, functions impairment. Recovering sexual function is one of the most important function tightly coupled with the life quality. In this respect, in the related literature can be found data regarding mainly: diagnosis/evaluation issues therapeutic/assistive-rehabilitative interventions (including connected to fertility troubles) and of psychological and or educational specific counseling, kind. Materials and methods.This paper presents a current systematic (of Preferred Reporting Items for Systematic Reviews and Meta-Analyses – PRISMA – type) and synthetic literature review on sexual dysfunctions and respected available management options in male subjects with SCI, using the following search keywords/ combinations of key words: “men”, “sexual dysfunction”/ “fertility” / “erectile dysfunction”/ “ejaculatory problems” / “sexual disorder“, “spinal cord injury”, “paraplegia”/ ”tetraplegia” /“paraplegic”/ ”tetraplegic”, “management”/ “treatment”, by interrogating international renown data bases: NCBI/PubMed, NCBI/PMC, Elsevier, PEDro and respectively, ISI Web of Knowledge/Science – to check whether the selected articles are published in ISI indexed journals – considering publications from January 2009 to June 2019, written in English, open access articles and being “fair”/“high” quality on our PEDro inspired, customized quality classification of the selected papers – the basic criterion, being the weighted citations number per year. Results. We have found initially 647 articles and eventually, after accomplishing the PRISMA stages (without meta-analysis), we have selected 16 articles matching all the above mentioned quest method’s requests (see further the figure representing our PRISMA type completed flow-diagram), covering (together with knowledge acquired from extra bibliographic resources, too). Conclusions. Sexual disfunctions after SCI are complex and strongly add to the severe and multimodal disability the affected people – in the case of our work: men – experience. Therefore, they worth being fathomed and periodically reappraised. Keywords: Spinal Cord injury (SCI), men sexual dysfunctions, systematic literature review, rehabilitation,

[Guidelines: neurogenic bowel dysfunction in spinal cord injury (long version)]

Die Leitlinie (AWMF-Register-Nr.: 179-004) „Neurogene Darmfunktionsstörung bei Querschnittlähmung“ der Deutschsprachigen Medizinischen Gesellschaft für Paraplegiologie ist an alle Personen adressiert, die Menschen mit kongenitalen oder erworbenen Querschnittlähmungen mit neurogenen Darmfunktionsstörungen (NDFS) betreuen. Insbesondere werden Ärzte, Pflegende und Therapeuten angesprochen. Die multiprofessionell erstellte Leitlinie (beteiligt waren Neuro-Urologen, Viszeralchirurgen, Gastroenterologen sowie Gesundheits- und Krankenpflegekräfte und Ernährungsberater sowie assoziierte Fachgesellschaften im Review-Verfahren) stellt eine praxisorientierte Unterstützung für die Versorgung von Patienten mit NDFS dar. Es werden Definitionen und aktuelles Wissen zur Diagnostik von NDFS sowie zu dem notwendigen konservativen Darmmanagement vermittelt, um eine kompetente Behandlung von Patienten mit NDFS zu gewährleisten. Dabei wird das Konzept der neurogenen Darmfunktionsstörung sowie deren klinische Auswirkungen beschrieben. Medikamentöse Interventionen und operative Eingriffe werden in Kurzform erläutert und Empfehlungen abgegeben. Das Hauptziel der vorliegenden Leitlinie besteht darin, Komplikationen inklusive der Stuhlinkontinenz und der Obstipation zu verhindern und so die Lebensqualität der Betroffenen positiv zu beeinflussen. Hilfreiche Anhänge, die im Alltag genutzt werden können, runden die Leitlinie ab.

Feasibility, acceptability, and preliminary efficacy of a handcycling high-intensity interval training program for individuals with spinal cord injury

Study Design:

Pilot non-randomized clinical trial

Objectives:

To examine the feasibility, acceptability and preliminary efficacy of performing handcycling high intensity interval training (HIIT) for six weeks in wheelchair users with spinal cord injury.

Setting:

Participant’s home

Methods:

Participants completed pre and post graded exercise stress tests, exercise surveys and six weeks of handcycling HIIT. The HIIT program consisted of two weekly, 25 minute supervised at-home sessions (2-3 min warm-up, then 10 intervals of cycling with a ratio of 1 minute work at 90% peak power output (PPO) to 1 minute recovery at 0-20% PPO, then 2-3 min cool-down). Real-time power output and heart rate were recorded via sensors and a bike computer. The sensor data were analyzed to evaluate training efficacy.

Results:

Seven of the 10 enrolled participants (70%) completed the study. All but one completed the required 12 sessions. The participants met at least one of the HIIT target intensity criteria in 76 out of 89 total sessions (85.4%) performed. Participants expressed a high level of enjoyment on the Physical Activity Enjoyment Scale, mean (SD) = 114.8 (11.3), and satisfaction with the overall experience. Five of the seven participants (71%) who completed the study felt an increase in endurance, function and health. Objective physiological changes showed mixed results.

Conclusions:

Six weeks of handcycling HIIT appears to be safe, feasible and acceptable. A longer HIIT work interval may be needed to elicit significant physiological responses. Future investigation of the feasibility and efficacy of differing HIIT parameters is needed.

Safety and feasibility of exoskeleton-assisted walking during acute/sub-acute SCI in an inpatient rehabilitation facility: A single-group preliminary study

Context/objective: Information on the safety and feasibility of lower extremity powered exoskeletons for persons with acute/sub-acute spinal cord injury (SCI) is limited. Understanding the safety and feasibility of employing powered exoskeletons in acute/sub-acute (<6 months post injury) at a SCI acute inpatient rehabilitation (SCI-AIR) facility could guide clinical practice and provide a basis for larger clinical trials on efficacy and effectiveness. Design: Single group observational study. Setting: SCI-AIR. Participants: Participants (n = 12; age: 28-71 years; 58% AIS D; 58% male) with neurological levels of injuries ranging from C2 to L3. Interventions: Up to 90 min of exoskeleton-assisted locomotor training was provided up to three times per week during SCI-AIR. Outcome measures: Safety of device use during inpatient locomotor training was quantified as the number of adverse events (AE) per device exposure hour. Feasibility of device use was defined in terms of protocol compliance, intensity, and proficiency. Results: Concerning safety, symptomatic hypotension was the most common AE reported at 111-events/exoskeleton-hours. Protocol compliance had a mean (SD) of 54% (30%). For intensity, 77% of participants incorporated variable assistance into at least 1 walking session; 70% of participants' sessions were completed with a higher RPE than the physical therapist. In proficiency, 58% achieved at least minimal assistance when walking with the device. Conclusion: Exoskeleton training in SCI-AIR can be safe and feasible for newly injured individuals with SCI who have clinically defined ambulatory goals. Nonetheless, sufficient controls to minimize risks for AEs, such as hypotensive events, are required.

Intermittent Fasting After Spinal Cord Injury Does Not Improve the Recovery of Baroreflex Regulation in the Rat

Modest recovery of somatic function after incomplete spinal cord injury (SCI) has been widely demonstrated. Recently we have shown that spontaneous recovery of baroreflex regulation of sympathetic activity also occurs in rats. Dietary restriction in the form of every other day fasting (EODF) has been shown to have beneficial effects on the recovery of motor function after SCI in rats. The goal of this study was to determine if EODF augments the improvement of baroreflex regulation of sympathetic activity after chronic left thoracic (T8) surgical spinal hemisection. To determine this, we performed baroreflex tests on ad-lib fed or EODF rats 1 week or 7 weeks after left T8 spinal hemisection. One week after T8 left hemisection baroreflex testing revealed that gain of baroreflex responsiveness, as well as the ability to increase renal sympathetic nerve activity (RSNA) at low arterial pressure, was significantly impaired in the ad-lib fed but not the EODF rats compared with sham lesioned control rats. However, baroreflex tests performed 7 weeks after T8 left hemisection revealed the inability of both ad-lib and EODF rats to decrease RSNA at elevated arterial pressures. While there is evidence to suggest that EODF has beneficial effects on the recovery of motor function in rats, EODF did not significantly improve the recovery of baroreflex regulation of sympathetic activity.

Cardiovascular Changes and Lumbar Spine Surgery: A Neglected Entity

Cardiovascular changes following lumbar spine surgeries in the prone position have been less commonly described. Here, we report a case of an elderly male patient undergoing lumbar spine decompression and transforaminal interbody fusion who developed multiple but transient episodes of hypotension and bradycardia. Anesthesiologist should be vigilant while monitoring such patients and should use invasive blood pressure monitoring if possible, so as to detect transient cardiovascular episodes which may progress and results in a dreadful outcome.

Attenuating Neurogenic Sympathetic Hyperreflexia Robustly Improves Antibacterial Immunity After Chronic Spinal Cord Injury

Spinal cord injury (SCI) disrupts critical physiological systems, including the cardiovascular and immune system. Plasticity of spinal circuits below the injury results in abnormal, heightened sympathetic responses, such as extreme, sudden hypertension that hallmarks life-threatening autonomic dysreflexia. Moreover, such sympathetic hyperreflexia detrimentally impacts other effector organs, including the spleen, resulting in spinal cord injury-induced immunodeficiency. Consequently, infection is a leading cause of mortality after SCI. Unfortunately, there are no current treatments that prophylactically limit sympathetic hyperreflexia to prevent subsequent effector organ dysfunction. The cytokine soluble tumor necrosis factor α (sTNFα) is upregulated in the CNS within minutes after SCI and remains elevated. Here, we report that commencing intrathecal administration of XPro1595, an inhibitor of sTNFα, at a clinically feasible, postinjury time point (i.e., 3 d after complete SCI) sufficiently diminishes maladaptive plasticity within the spinal sympathetic reflex circuit. This results in less severe autonomic dysreflexia, a real-time gauge of sympathetic hyperreflexia, for months postinjury. Remarkably, delayed delivery of the sTNFα inhibitor prevents sympathetic hyperreflexia-associated splenic atrophy and loss of leukocytes to dramatically improve the endogenous ability of chronic SCI rats to fight off pneumonia, a common cause of hospitalization after injury. The improved immune function with XPro1595 correlates with less noradrenergic fiber sprouting and normalized norepinephrine levels in the spleen, indicating that heightened, central sTNFα signaling drives peripheral, norepinephrine-mediated organ dysfunction, a novel mechanism of action. Thus, our preclinical study supports intrathecally targeting sTNFα as a viable strategy to broadly attenuate sympathetic dysregulation, thereby improving cardiovascular regulation and immunity long after SCI.SIGNIFICANCE STATEMENT Spinal cord injury (SCI) significantly disrupts immunity, thus increasing susceptibility to infection, a leading cause of morbidity in those living with SCI. Here, we report that commencing intrathecal administration of an inhibitor of the proinflammatory cytokine soluble tumor necrosis factor α days after an injury sufficiently diminishes autonomic dysreflexia, a real time gauge of sympathetic hyperreflexia, to prevent associated splenic atrophy. This dramatically improves the endogenous ability of chronically injured rats to fight off pneumonia, a common cause of hospitalization. This preclinical study could have a significant impact for broadly improving quality of life of SCI individuals.

Toward the Existence of a Sympathetic Neuroplasticity Adaptive Mechanism Influencing the Immune Response. A Hypothetical View-Part II

In the preceding work, a hypothesis on the existence of a specific neural plasticity program from sympathetic fibers innervating secondary lymphoid organs was introduced. This proposed adaptive mechanism would involve segmental retraction and degeneration of noradrenergic terminals during the immune system (IS) activation followed by regeneration once the IS returns to the steady-state. Starting from such view, this second part presents clinical and experimental evidence allowing to envision that this sympathetic neural plasticity mechanism is also operative on inflamed non-lymphoid peripheral tissues. Importantly, the sympathetic nervous system regulates most of the physiological bodily functions, ranging from cardiovascular, respiratory and gastro-intestinal functions to endocrine and metabolic ones, among others. Thus, it seems sensible to think that compensatory programs should be put into place during inflammation in non-lymphoid tissues as well, to avoid the possible detrimental consequences of a sympathetic blockade. Nevertheless, in many pathological scenarios like severe sepsis, chronic inflammatory diseases, or maladaptive immune responses, such compensatory programs against noradrenergic transmission impairment would fail to develop. This would lead to a manifest sympathetic dysfunction in the above-mentioned settings, partly accounting for their underlying pathophysiological basis; which is also discussed. The physiological/teleological significance for the whole neural plasticity process is postulated, as well.

A case of postprandial hypotension in an individual with cervical spinal cord injury: treatment with acarbose

Introduction

Postprandial hypotension (PPH) is a postmeal drop in systolic blood pressure that may or may not be symptomatic. While the etiologies of PPH are incompletely understood, it is thought to occur when glucose absorption causes increased splanchnic blood flow or "pooling" in people who lack sufficient compensatory responses to support their systemic blood pressure. Postprandial hypotension is well described in individuals with neurodegenerative diseases, yet only rarely in people living with spinal cord injury (SCI). Acarbose is an alpha-glucosidase inhibitor that treats PPH by slowing gastric transit time and reducing glucose uptake in the small intestine, hence decreasing superior mesenteric artery blood flow.

Case presentation

A 62-year-old woman with long-standing cervical SCI presented with 5 years of worsening postprandial lightheadedness, visual "flashes", and neck pain. She had had multiple episodes of near and frank syncope and her prior medical team had initiated midodrine three times daily. We began treatment with acarbose, starting at 50 mg with each meal and rapidly titrating to 100 mg at mealtime. She noticed an immediate improvement in her symptoms and an attenuation of postmeal drops in both systolic and diastolic blood pressures.

Discussion

To our knowledge, this is one of the first described cases of PPH among people living with SCI. Given the autonomic dysfunction that frequently accompanies higher-level of injuries, it is possible that many more people with SCI have this condition, whether or not it is symptomatic. Acarbose is one of the several established treatments for PPH, and proved effective and tolerable for our patient.

Efficacy of low molecular weight heparin in spinal trauma patients after part concentrated screw surgery and its influence on blood parameters and the incidence of deep venous thrombosis

This study was to investigate the efficacy of low molecular weight heparin (LMWH) therapy in patients with spinal trauma after part concentrated screw (PCS) pedicle screw surgery (PSS) and its influence on blood parameters and the incidence of deep venous thrombosis. Prospectively, 36 patients with spinal trauma who underwent PSS were randomly divided into an experimental group (n = 18) and a control group (n = 18). The experimental group was treated with LMWH after the operation. Changes in the vascular endothelial function, inflammatory factors and other blood indexes, and the incidence of deep venous thrombosis in lower extremities were compared between the two groups before and after the surgery. Compared to pre-surgery, the levels of endothelin (ET) and tissue plasminogen activator (tPA) in the experimental group decreased significantly after surgery (all P < 0.001), while the levels of ET increased and tPA decreased significantly in the control group (all P < 0.001). In addition, compared with pre-surgical levels, interleukin-8 (IL-8), IL-6 and procalcitonin (PCT) decreased significantly in the experimental group after surgery while there was a significant increase in these cytokines in the control group (all P < 0.001), with a significant difference in the cytokine levels between the two groups post-surgery (P < 0.01). After the surgery, plasma viscosity, erythrocyte electrophoresis time and platelet aggregation rate in the control group were significantly increased from pre-surgery levels (all P < 0.001), and these levels were also significantly higher than in the experimental group (P < 0.01). The D-dimer (D-D) level in both groups also increased significantly after surgery (all P < 0.001), and the level post-surgery was significantly higher in the experimental group as compared to the control group (P < 0.01). Finally, the incidence of deep venous thrombosis in the experimental group was significantly lower than in the control group (P < 0.05). LMWH is beneficial in reducing the degree of hypercoagulability, hyperviscosity and inflammatory reaction in patients with spinal trauma who underwent PSS. It also effectively reduced the occurrence of deep vein thrombosis in lower limbs after surgery. Thus, it is a candidate for further clinical development.

Level-Specific Differences in Systemic Expression of Pro- and Anti-Inflammatory Cytokines and Chemokines after Spinal Cord Injury

While over half of all spinal cord injuries (SCIs) occur in the cervical region, the majority of preclinical studies have focused on models of thoracic injury. However, these two levels are anatomically distinct—with the cervical region possessing a greater vascular supply, grey-white matter ratio and sympathetic outflow relative to the thoracic region. As such, there exists a significant knowledge gap in the secondary pathology at these levels following SCI. In this study, we characterized the systemic plasma markers of inflammation over time (1, 3, 7, 14, 56 days post-SCI) after moderate-severe, clip-compression cervical and thoracic SCI in a rat model. Using high-throughput ELISA panels, we observed a clear level-specific difference in plasma levels of VEGF, leptin, IP10, IL18, GCSF, and fractalkine. Overall, cervical SCI had reduced expression of both pro- and anti-inflammatory proteins relative to thoracic SCI, likely due to sympathetic dysregulation associated with higher level SCIs. However, contrary to the literature, we did not observe level-dependent splenic atrophy with our incomplete SCI model. This is the first study to compare the systemic plasma-level changes following cervical and thoracic SCI using level-matched and time-matched controls. The results of this study provide the first evidence in support of level-targeted intervention and also challenge the phenomenon of high SCI-induced splenic atrophy in incomplete SCI models.

Paced breathing and phrenic nerve responses evoked by epidural stimulation following complete high cervical spinal cord injury in rats

Spinal cord injury (SCI) at the level of cervical segments often results in life-threatening respiratory complications and requires long-term mechanical ventilator assistance. Thus restoring diaphragm activity and regaining voluntary control of breathing are the primary clinical goals for patients with respiratory dysfunction following cervical SCI. Epidural stimulation (EDS) is a promising strategy that has been explored extensively for nonrespiratory functions and to a limited extent within the respiratory system. The goal of the present study is to assess the potential for EDS at the location of the phrenic nucleus (C₃-C₅) innervating the diaphragm: the main inspiratory muscle following complete C₁ cervical transection. To avoid the suppressive effect of anesthesia, all experiments were performed in decerebrate, C₁ cervical transection, unanesthetized, nonparalyzed ( n = 13) and paralyzed ( n = 7) animals. Our results show that C₄ segment was the most responsive to EDS and required the lowest threshold of current intensity, affecting tracheal pressure and phrenic nerve responses. High-frequency (200-300 Hz) EDS applied over C₄ segment (C₄-EDS) was able to maintain breathing with normal end-tidal CO₂ level and raise blood pressure. In addition, 100-300 Hz of C₄-EDS showed time- and frequency-dependent changes (short-term facilitation) of evoked phrenic nerve responses that may serve as a target mechanism for pacing of phrenic motor circuits. The present work provides the first report of successful EDS at the level of phrenic nucleus in a complete SCI animal model and offers insight into the potential therapeutic application in patients with high cervical SCI. NEW & NOTEWORTHY The present work offers the first demonstration of successful life-supporting breathing paced by epidural stimulation (EDS) at the level of the phrenic nucleus, following a complete spinal cord injury in unanesthetized, decerebrate rats. Moreover, our experiments showed time- and frequency-dependent changes of evoked phrenic nerve activity during EDS that may serve as a target mechanism for pacing spinal phrenic motor networks.

The brainstem network controlling blood pressure: an important role for pressor sites in the caudal medulla and cervical spinal cord

: Although medullary control of blood pressure (BP) has been extensively studied, the contribution of critical regions, such as pressor sites in the caudal medulla and upper cervical spinal cord and the lateral tegmental field, remains controversial and underappreciated. A series of pressor sites caudal to the caudal ventrolateral medulla (CVLM), including the caudal pressor area (CPA) and medullocervical pressor area, play an important role in control of BP. Activation and inhibition of these sites elicits pressor and depressor responses, respectively. Basal sympathetic tone is provided principally by the medullary lateral tegmental field and rostral ventrolateral medulla (RVLM). RVLM presympathetic neurons, which project to and drive preganglionic sympathetic somata in the intermediolateral cell column, are powerfully regulated by neurons in CVLM via tonic and phasic inhibition. The current state of knowledge is summarized thus: rostrocaudally organized columns of pressor sites caudal to CVLM extend to the upper cervical spinal cord; CPA pressor responses are RVLM-dependent; CPA mediates pressor responses by (first) inhibiting RVLM-projecting inhibitory CVLM units and (second) activating RVLM-projecting excitatory CVLM units; the chemoreflex is CPA-dependent; the baroreflex is CPA-independent; pressor responses to raphe obscurus stimulation are CPA-dependent; and medullocervical pressor area pressor responses are RVLM-independent, likely mediated by direct projections to the intermediolateral cell column. In this review, we seek to underscore and characterize the critical role played by the caudal medulla and upper cervical spinal cord in BP regulation and highlight important gaps in knowledge in interactions between the caudal medulla and other regions controlling BP, which may prove critical in revealing central mechanisms underlying pathophysiology of, and pharmacotherapeutic targets for, hypertension.

Incidence and Natural Progression of Neurogenic Shock after Traumatic Spinal Cord Injury

Neurogenic shock, a distributive type of circulatory shock after spinal cord injury (SCI), results in profound hypotension. The consequent hemodynamic instability complicates clinical management, delays surgical intervention, and impacts neurological outcome. Moreover, the reported incidence of this condition varies significantly. We establish the true incidence of neurogenic shock by comparing the most common clinical definitions used to diagnose the condition. Further, we characterize the acute progression and recovery of neurogenic shock. Daily blood pressure, heart rate, and fluid management as well as vasopressor therapy and neurologic status were collected over 30 days from 84 adults admitted to our tertiary trauma center after cervical (n = 56) and thoracic (n = 28) SCI. We found that the reported incidence of neurogenic shock varied greatly depending on which clinical definition was applied. By using a novel combination of hemodynamic and laboratory criteria to define neurogenic shock, the calculated incidence (29% cervical SCI) in our sample most appropriately reflects the true incidence, finding that hypovolemia was the primary factor responsible for the inconsistency in incidence reports between studies. In addition, we found a characteristic decline in blood pressure after the first week post-injury and that fluid management is not currently an integral aspect of clinical management (all persons were treated at a net fluid intake ≤ zero). The results demonstrate the need for accurate identification of neurogenic shock through consistent and appropriate criteria, which is not only important from a clinical point of view, but also in establishing accurate epidemiology to responsibly allocate resources to its management.

Mechanical Stress by Spasticity Accelerates Fracture Healing After Spinal Cord Injury

Accelerated fracture healing in patients with spinal cord injuries (SCI) is often encountered in clinical practice. However, there is no distinct evidence in the accelerated fracture healing, and the mechanisms of accelerated fracture healing in SCI are poorly understood. We aimed to determine whether SCI accelerated fracture healing in morphology and strength, to characterize the healing process with SCI, and to clarify the factors responsible for accelerated fracture healing. In total, 39 male Wistar rats were randomly divided into healthy control without intervention, SCI only, fracture with SCI, botulinum toxin (BTX) A-treated fracture with SCI, and propranolol-treated fracture with SCI groups. These rats were assessed with computed microtomography, histological, histomorphological, immunohistological, and biomechanical analyses. Both computed microtomography and histological analyses revealed the acceleration of a bony union in animals with SCI. The strength of the healed fractures after SCI recovered to the same level as that of intact bones after SCI, while the healed bones were weaker than the intact bones. Immunohistology revealed that SCI fracture healing was characterized by formation of callus with predominant intramembranous ossification and promoting endochondral ossification. The accelerated fracture healing after SCI was attenuated by BTX injection, but did not change by propranolol. We demonstrated that SCI accelerate fracture healing in both morphology and strength. The accelerated fracture healing with SCI may be due to predominant intramembranous ossification and promoting endochondral ossification. In addition, our results also suggest that muscle contraction by spasticity accelerates fracture healing after SCI.

Baroreflex autonomic control in human spinal cord injury: Physiology, measurement, and potential alterations

The arterial baroreflex is a primary regulator of autonomic outflow to effectively regulate acute changes in blood pressure. After a spinal cord injury (SCI), regulation of autonomic function is disrupted, although the damage of the autonomic pathways may not necessarily be related to the severity of injury (i.e. level and completeness). Nonetheless, it can be assumed that there would be greater loss of sympathetic innervation with higher level of injury and that cardiac parasympathetic control would remain intact regardless of injury level. In those with SCI, impaired baroreflex regulation has implications not only for adequate pressure regulation, but also for long term cardiovascular health. In this review, we discuss the expected impact ofan SCI on baroreflex control and the studies that have investigated baroreflex sensitivity in this population. The data generally indicates that baroreflex sensitivity is lesser in those with chronic injuries. However, these findings are counter to the expected effect of an SCI and hence may indicate that the effect of an SCI on baroreflex control might be secondary to long term deconditioning and/or vascular stiffening of baroreceptive arteries. Furthermore, the alterations in the ability to regulate pressure do not impact the relationship between spontaneous heart rate and blood pressure variabilities. In addition, those with SCI are not adequately able to control blood pressure changes in response to orthostasis, resulting in frank hypotension in a significant proportion of those with high level injuries.

Cardiovascular Dysfunction Presenting as Autonomic Dysreflexia in a Patient with Spinal Cord Injury

Autonomic dysreflexia (AD) is a medical emergency that is characterized by hypertension as an autonomic response to noxious stimuli in patients with a history of spinal cord injury at the level of T6 or above. We present the case of a 31-year-old Caucasian male with a history of spinal cord injury at the level of C3-C4, with symptoms described as recurring episodes of hypertension with flushing and sweating above the level of the lesion for the past five to six years. His symptoms are triggered by bowel distention, excitement, a bumpy car ride, or a simple turning of the neck to the left. Physical examination and laboratory studies ruled out other possible differentials (e.g., migraines, pheochromocytoma). As a result, AD was diagnosed.