Intraspinal Pressure Monitoring and Extensive Duroplasty in the Acute Phase of Traumatic Spinal Cord Injury: A Systematic Review

Liposome-Hydrogel Composites for Controlled Drug Delivery Applications

Various controlled delivery systems (CDSs) have been developed to overcome the shortcomings of traditional drug formulations (tablets, capsules, syrups, ointments, etc.). Among innovative CDSs, hydrogels and liposomes have shown great promise for clinical applications thanks to their cost-effectiveness, well-known chemistry and synthetic feasibility, biodegradability, biocompatibility and responsiveness to external stimuli. To date, several liposomal- and hydrogel-based products have been approved to treat cancer, as well as fungal and viral infections, hence the integration of liposomes into hydrogels has attracted increasing attention because of the benefit from both of them into a single platform, resulting in a multifunctional drug formulation, which is essential to develop efficient CDSs. This short review aims to present an updated report on the advancements of liposome-hydrogel systems for drug delivery purposes.

Spinal decompression surgery may alleviate vasopressor-induced spinal hemorrhage and extravasation during acute cervical spinal cord injury in rats

BACKGROUND

Cervical spinal injury often disrupts the supraspinal vasomotor pathways projecting to the thoracic sympathetic preganglionic neurons, leading to cardiovascular dysfunction. The current guideline is to maintain the mean arterial blood pressure at 85 to 90 mmHg using a vasopressor during the first week of the injury. Some studies have demonstrated that this treatment might be beneficial to alleviate secondary injury and improve neurological outcomes; however, elevation of blood pressure may exacerbate spinal hemorrhage, extravasation, and edema, exacerbating the initial injury.

PURPOSE

The present study was designed to (1) examine whether vasopressor administration exacerbates spinal hemorrhage and extravasation; (2) evaluate whether spinal decompression surgery relieves vasopressor-induced spinal hemorrhage and extravasation.

STUDY DESIGN

In vivo animal study.

METHODS

Animals received a saline solution or a vasopressor (phenylephrine hydrochloride, 500 or 1000 μg/kg, 7 mL/kg/h) after mid-cervical contusion with or without spinal decompression (ie, incision of the dura and arachnoid mater). Spinal cord hemorrhage and extravasation were examined by expression of Evans blue within the spinal cord section.

RESULTS

The results demonstrated that cervical spinal contusion significantly reduced the mean arterial blood pressure and induced spinal hemorrhage and extravasation. Phenylephrine infusion significantly elevated the mean arterial blood pressure to the preinjury level within 15 to 60 minutes postcontusion; however, spinal hemorrhage and extravasation were more extensive in animals that received phenylephrine than in those that received saline. Notably, spinal decompression mitigated spinal hemorrhage and extravasation in contused rats who received phenylephrine.

CONCLUSIONS

These data indicate that, although phenylephrine can prevent hypotension after cervical spinal injury, it also causes excess spinal hemorrhage and extravasation.

CLINICAL SIGNIFICANCE

Spinal decompressive surgery seemed to minimize the side effect of phenylephrine as vasopressor treatment during acute spinal cord injury.

Interventions to Optimize Spinal Cord Perfusion in Patients With Acute Traumatic Spinal Cord Injury: An Updated Systematic Review

STUDY DESIGN

Systematic review update.

OBJECTIVES

Interventions that aim to optimize spinal cord perfusion are thought to play an important role in minimizing secondary ischemic damage and improving outcomes in patients with acute traumatic spinal cord injuries (SCIs). However, exactly how to optimize spinal cord perfusion and enhance neurologic recovery remains controversial. We performed an update of a recent systematic review (Evaniew et al, J. Neurotrauma 2020) to evaluate the effects of Mean Arterial Pressure (MAP) support or Spinal Cord Perfusion Pressure (SCPP) support on neurological recovery and rates of adverse events among patients with acute traumatic SCI.

METHODS

We searched PubMed/MEDLINE, EMBASE and ClinicalTrials.gov for new published reports. Two reviewers independently screened articles, extracted data, and evaluated risk of bias. We implemented the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach to rate confidence in the quality of the evidence.

RESULTS

From 569 potentially relevant new citations since 2019, we identified 9 new studies for inclusion, which were combined with 19 studies from a prior review to give a total of 28 studies. According to low or very low quality evidence, the effect of MAP support on neurological recovery is uncertain, and increased SCPP may be associated with improved neurological recovery. Both approaches may involve risks for specific adverse events, but the importance of these adverse events to patients remains unclear. Very low quality evidence failed to yield reliable guidance about particular monitoring techniques, perfusion ranges, pharmacological agents, or durations of treatment.

CONCLUSIONS

This update provides an evidence base to support the development of a new clinical practice guideline for the hemodynamic management of patients with acute traumatic SCI. While avoidance of hypotension and maintenance of spinal cord perfusion are important principles in the management of an acute SCI, the literature does not provide high quality evidence in support of a particular protocol. Further prospective, controlled research studies with objective validated outcome assessments are required to examine interventions to optimize spinal cord perfusion in this setting.

Randomized Controlled Trial of Durotomy as an Adjunct to Routine Decompressive Surgery for Dogs With Severe Acute Spinal Cord Injury

Although many interventions for acute spinal cord injury (SCI) appear promising in experimental models, translation directly from experimental animals to human patients is a large step that can be problematic. Acute SCI occurs frequently in companion dogs and may provide a model to ease translation. Recently, incision of the dura has been highlighted in both research animals and human patients as a means of reducing intraspinal pressure, with a view to improving perfusion of the injured tissue and enhancing functional recovery. Observational clinical data in humans and dogs support the notion that it may also improve functional outcome. Here, we report the results of a multi-center randomized controlled trial of durotomy as an adjunct to traditional decompressive surgery for treatment of severe thoracolumbar SCI caused by acute intervertebral disc herniation in dogs. Sample-size calculation was based on the proportion of dogs recovering ambulation improving from an expected 55% in the traditional surgery group to 70% in the durotomy group. Over a 3.5-year period, we enrolled 140 dogs, of which 128 had appropriate duration of follow-up. Overall, 65 (51%) dogs recovered ambulation. Recovery in the traditional decompression group was 35 of 62 (56%) dogs, and in the durotomy group 30 of 66 (45%) dogs, associated with an odds ratio of 0.643 (95% confidence interval: 0.320-1.292) and z-score of -1.24. This z-score indicates trial futility to reach the target 15% improvement over traditional surgery, and the trial was terminated at this stage. We conclude that durotomy is ineffective in improving functional outcome for severe acute thoracolumbar SCI in dogs. In the future, these data can be compared with similar data from clinical trials on duraplasty in human patients and will aid in determining the predictive validity of the "companion dog model" of acute SCI.

A future blood test for acute traumatic spinal cord injury

Acute spinal cord injury (SCI) requires prompt diagnosis and intervention to minimize the risk of permanent neurologic deficit. Presently, SCI diagnosis and interventional planning rely on magnetic resonance imaging (MRI), which is not always available or feasible for severely injured patients. Detection of disease-specific biomarkers in biofluids via liquid biopsy may provide a more accessible and objective means of evaluating patients with suspected SCI. Cell-free DNA, which has been used for diagnosing and monitoring oncologic disease, may detect damage to spinal cord neurons via tissue-specific methylation patterns. Other types of biomarkers, including proteins and RNA species, have also been found to reflect neuronal injury and may be included as part of a multi-analyte assay to improve liquid biopsy performance. The feasibility of implementing liquid biopsy into current practices of SCI management is supported by the relative ease of blood sample collection as well as recent advancements in droplet digital polymerase chain reaction technology. In this review, we detail the current landscape of biofluid biomarkers for acute SCI and propose a framework for the incorporation of a putative blood test into the clinical management of SCI.

A Review of Strategies Associated with Surgical Decompression in Traumatic Spinal Cord Injury

Traumatic spinal cord injury (TSCI) is frequent. Timely diagnosis and treatment have reduced the mortality, but the long-term recovery of neurologic functions remains ominous. After TSCI, tissue bleeding, edema, and adhesions lead to an increase in the intraspinal pressure, further causing the pathophysiologic processes of ischemia and hypoxia and eventually accelerating the cascade of secondary spinal cord injury. Timely surgery with appropriate decompression strategies can reduce that secondary injury. However, disagreement about the safety and effectiveness of decompression surgery and the timing of surgery still exists. The level and severity of spinal cord injury do have an impact on the timing of surgery; therefore, TSCI subpopulations may benefit from early surgery. Early surgery perhaps has little effect on recovery from complete TSCI but might be of benefit in patients with incomplete injury. Early decompression should be considered in patients with incomplete cervical TSCI. Patient age should not be used as an exclusion criterion for early surgery. The best time point for early surgery is although influenced by the shortest duration to thoroughly examine the patient's condition and stabilize the patient's state. After the patient's condition is fully evaluated, we can perform the surgical modality of emergency myelotomy and decompression. Therefore, a number of conditions should be considered, such as standardized decompression methods, indications and operation timing to ensure the effectiveness and safety of early surgical intervention, and promotion of the functional recovery of residual nerve tissue.

Multimodal interventions to optimize spinal cord perfusion in patients with acute traumatic spinal cord injuries: a systematic review

OBJECTIVE

The authors systematically reviewed current evidence for the utility of mean arterial pressure (MAP), intraspinal pressure (ISP), and spinal cord perfusion pressure (SCPP) as predictors of outcomes after traumatic spinal cord injury (SCI).

METHODS

PubMed, Cochrane Reviews Library, EMBASE, and Scopus databases were queried in December 2020. Two independent reviewers screened articles using Covidence software. Disagreements were resolved by a third reviewer. The inclusion criteria for articles were 1) available in English; 2) full text; 3) clinical studies on traumatic SCI interventions; 4) involved only human participants; and 5) focused on MAP, ISP, or SCPP. Exclusion criteria were 1) only available in non-English languages; 2) focused only on the brain; 3) described spinal diseases other than SCI; 4) interventions altering parameters other than MAP, ISP, or SCPP; and 5) animal studies. Studies were analyzed qualitatively and grouped into two categories: interventions increasing MAP or interventions decreasing ISP. The Scottish Intercollegiate Guidelines Network level of evidence was used to assess bias and the Grading of Recommendations, Assessment, Development, and Evaluation approach was used to rate confidence in the anticipated effects of each outcome.

RESULTS

A total of 2540 unique articles were identified, of which 72 proceeded to full-text review and 24 were included in analysis. One additional study was included retrospectively. Articles that went through full-text review were excluded if they were a review paper (n = 12), not a full article (n = 12), a duplicate paper (n = 9), not a human study (n = 3), not in English (n = 3), not pertaining to traumatic SCI (n = 3), an improper intervention (n = 3), without intervention (n = 2), and without analysis of intervention (n = 1). Although maintaining optimal MAP levels is the current recommendation for SCI management, the published literature supports maintenance of SCPP as a stronger indicator of favorable outcomes. Studies also suggest that laminectomy and durotomy may provide better outcomes than laminectomy alone, although higher-level studies are needed. Current evidence is inconclusive on the effectiveness of CSF drainage for reducing ISP.

CONCLUSIONS

This review demonstrates the importance of assessing how different interventions may vary in their ability to optimize SCPP.

Significance of spinal cord perfusion pressure following spinal cord injury: A systematic scoping review

This scoping review systematically reviewed relevant research to summarize the literature addressing the significance of monitoring spinal cord perfusion pressure (SCPP) in acute traumatic spinal cord injury (SCI). The objectives of the review were to (1) examine the nature of research in the field of SCPP monitoring in SCI, (2) summarize the key research findings in the field, and (3) identify research gaps in the existing literature and future research priorities. Primary literature searches were conducted using databases (Medline and Embase) and expanded searches were conducted by reviewing the references of eligible articles and searches of Scopus, Web of Science core collection, Google Scholar, and conference abstracts. Relevant data were extracted from the studies and synthesis of findings was guided by the identification of patterns across studies to identify key themes and research gaps within the literature. Following primary and expanded searches, a total of 883 articles were screened. Seventy-three articles met the review inclusion criteria, including 34 original research articles. Other articles were categorized as conference abstracts, literature reviews, systematic reviews, letters to the editor, perspective articles, and editorials. Key themes relevant to the research question that emerged from the review included the relationship between SCPP and neurological recovery, the safety of monitoring pressures within the intrathecal space, and methods of intervention to enhance SCPP in the setting of acute traumatic SCI. Original research that aims to enhance SCPP by targeting increases in mean arterial pressure or reducing pressure in the intrathecal space is reviewed. Further discussion regarding where pressure within the intrathecal space should be measured is provided. Finally, we highlight research gaps in the literature such as determining the feasibility of invasive monitoring at smaller centers, the need for a better understanding of cerebrospinal fluid physiology following SCI, and novel pharmacological interventions to enhance SCPP in the setting of acute traumatic SCI. Ultimately, despite a growing body of literature on the significance of SCPP monitoring following SCI, there are still a number of important knowledge gaps that will require further investigation.

The Winnipeg Intraspinal Pressure Monitoring Study (WISP): A protocol for validation of fiberoptic pressure monitoring for acute traumatic spinal cord injury

Background

Research efforts have been focused on limiting secondary injury after traumatic spinal cord injury by performing spinal decompression and early optimization of spinal cord perfusion. The Winnipeg Intraspinal Pressure Monitoring Study (WISP) was designed to validate the technique of intraspinal pressure monitoring at the site of injury using a fiberoptic pressure monitor placed at the site of injury.

Objectives

To describe the design of the WISP study.

Study design

Descriptive.

Methods

We explain the current limitations in the available scientific literature around the topic of blood pressure management for acute traumatic spinal cord injury and rational for the WISP study. Then, we describe the design of WISP including the patient selection criteria, study interventions, follow up schedules and outcome measurements. A multitude of future research avenues are also discussed.

Results

The WISP study is a single center pilot study designed to validate the technique of intraspinal pressure monitoring following acute traumatic spinal cord injury. The study involves the measurement of intraspinal pressure from within the subarachnoid space at the site of injury to derive a number of physiological parameters including spinal cord perfusion pressure, spinal cord blood volume, measures of spinal cord compliance and vascular reactivity indices. Twenty eligible patients will be recruited and followed for a period of 12 months with visits scheduled for the first 5 days and 1, 3, 6, and 12 months following surgical intervention.

Conclusions

The WISP study will provide the first attempt in North America at validation of intraspinal pressure monitoring with a fiberoptic pressure monitor at the site of injury. Successful validation will lead to future studies to define optimal spinal cord perfusion pressure, relationships of neural injury biomarkers and outcomes as well as epigenetic studies.

Trial registration

This study has been registered at clinicaltrials.gov (registration# NCT04550117).

Established and Emerging Therapies in Acute Spinal Cord Injury

Acute spinal cord injury (SCI) is devastating for patients and their caretakers and has an annual incidence of 20–50 per million people. Following initial assessment with appropriate physical examination and imaging, patients who are deemed surgical candidates should undergo decompression with stabilization. Earlier intervention can improve neurological recovery in the post-operative period while allowing earlier mobilization. Optimized medical management is paramount to improve outcomes. Emerging strategies for managing SCI in the acute period stem from an evolving understanding of the pathophysiology of the injury. General areas of focus include ischemia prevention, reduction of secondary injury due to inflammation, modulation of the cytotoxic and immune response, and promotion of cellular regeneration. In this article, we review established, emerging, and novel experimental therapies. Continued translational research on these methods will improve the feasibility of bench-to-bedside innovations in treating patients with acute SCI.

Pharmacologic and Acute Management of Spinal Cord Injury in Adults and Children

Purpose of Review

This review provides guidance for acute spinal cord injury (SCI) management through an analytical assessment of the most recent evidence on therapies available for treating SCI, including newer therapies under investigation. We present an approach to the SCI patient starting at presentation to acute rehabilitation and prognostication, with additional emphasis on the pediatric population when evidence is available.

Recent Findings

Further studies since the Surgical Timing in Acute Spinal Cord Injury Study (STASCIS) demonstrated a potential functional outcome benefit with ultra-early surgical intervention ≤ 8 h post-SCI. Subsequent analysis of the National Acute Spinal Cord Injury Study (NASCIS) II and NASCIS III trials have demonstrated potentially serious complications from intravenous methylprednisolone with limited benefit. Newer therapies actively being studied have demonstrated limited or no benefit in preclinical and clinical trials with insufficient evidence to support use in acute SCI treatment.

Summary

Care for SCI patients requires a multi-disciplinary team. Immediate evaluation and management are focused on preventing additional injury and restoring perfusion to the affected cord. Rapid assessment and intervention involve focused neurological examination, targeted imaging, and surgical intervention when indicated. There are currently no evidence-based recommendations for pathomechanistically targeted therapies.

Detection and Analysis of Perfusion Pressure through Measuring Oxygen Saturation and Requirement of Dural Incision Decompression after Laminectomy

BACKGROUND

Traumatic spinal cord injury (SCI) can continue and transform long after the time of initial injury. Preventing secondary injury after SCI is one of the most significant challenges, and early intervention to return the blood flow at the injury site can minimize the likelihood of secondary injury.

OBJECTIVE

The purpose of this study is to investigate whether laminectomy can achieve the spinal cord blood flow by measuring the spinal blood oxygen saturation intraoperatively without the presence of light.

METHODS

Between June and August 2021, eight patients were admitted after traumatic spinal cord injury for surgical treatment. We explored the effectiveness of laminectomy and whether the patients required further procedures or not. We used a brain oxygen saturation monitor at the spine injury site under dark conditions.

RESULTS

Eight cervical trauma patients, six males and two females, underwent laminectomy decompression. Three patients' ASIA grade improved by one level, and one patient showed slight motor-sensory improvement. Oxygen saturation was in the normal range.

CONCLUSION

Performing bony decompression can show good results. Therefore, finding an examination method to confirm the improvement of blood perfusion by measuring oxygen saturation at the injury site after laminectomy is essential to avoid other complications.

Medical Communication Services after Traumatic Spinal Cord Injury

It is difficult to assess and monitor the spinal cord injury (SCI) because of its pathophysiology after injury, with different degrees of prognosis and various treatment methods, including laminectomy, durotomy, and myelotomy. Medical communication services with different factors such as time of surgical intervention, procedure choice, spinal cord perfusion pressure (SCPP), and intraspinal pressure (ISP) contribute a significant role in improving neurological outcomes. This review aims to show the benefits of communication services and factors such as ISP, SCPP, and surgical intervention time in order to achieve positive long-term outcomes after an appropriate treatment method in SCI patients. The SCPP was found between 90 and 100 mmHg for the best outcome, MAP was found between 110 and 130 mmHg, and mean ISP is ≤20 mmHg after injury. Laminectomy alone cannot reduce the pressure between the dura and swollen cord. Durotomy and duroplasty considered as treatment choices after severe traumatic spinal cord injury (TSCI).

Current updates on various treatment approaches in the early management of acute spinal cord injury

Spinal cord injury (SCI) is a debilitating condition which often leads to a severe disability and ultimately impact patient's physical, psychological, and social well-being. The management of acute SCI has evolved over the couple of decades due to improved understanding of injury mechanisms and increasing knowledge of disease. Currently, the early management of acute SCI patient includes pharmacological agents, surgical intervention and newly experimental neuroprotective strategies. However, many controversial areas are still surrounding in the current treatment strategies for acute SCI, including the optimal timing of surgical intervention, early versus delayed decompression outcome benefits, the use of methylprednisolone. Due to the lack of consensus, the optimal standard of care has been varied across treatment centres. The authors have shed a light on the current updates on early treatment approaches and neuroprotective strategies in the initial management of acute SCI in order to protect the early neurologic injury and reduce the future disability.

Effects of durotomy versus myelotomy in the repair of spinal cord injury

Current management for spinal cord injury aims to reduce secondary damage and recover sensation and movement. Acute spinal cord injury is often accompanied by spinal cord compartment syndrome. Decompression by durotomy and/or myelotomy attempts to relieve secondary damage by completelyrelieving the compression of the spinal cord, removing the necrotic tissue, decreasing edema, reducing hemorrhage, and improving blood circulation in the spinal cord. However, it is controversial whether durotomy and/or myelotomy after spinal cord injury are beneficial to neurological recovery. This review compares the clinical effects of durotomy with those of myelotomy in the treatment of spinal cord injury. We found that durotomy has been performed more than myelotomy in the clinic, and that durotomy may be safer and more effective than myelotomy. Durotomy performed in humans had positive effects on neurological function in 92.3% of studies in this review, while durotomy in animals had positive effects on neurological function in 83.3% of studies. Myelotomy procedures were effective in 80% of animal studies, but only one clinical study of myelotomy has reported positive results, of motor and sensory improvement, in humans. However, a number of new animal studies have reported that durotomy and myelotomy are ineffective for spinal cord injury. More clinical data, in the form of a randomized controlled study, are needed to understand the effectiveness of durotomy and myelotomy.

Interventions to Optimize Spinal Cord Perfusion in Patients with Acute Traumatic Spinal Cord Injuries: A Systematic Review

Interventions to optimize spinal cord perfusion via support of mean arterial pressure (MAP) or spinal cord perfusion pressure (SCPP) are thought to play a critical role in the management of patients with acute traumatic spinal cord injuries, but there is ongoing controversy about efficacy and safety. We aimed to determine the effects of optimizing spinal cord perfusion on neurological recovery and risks for adverse events. We searched multiple databases for published and unpublished reports. Two reviewers independently screened articles, extracted data, and evaluated risk of bias. We synthesized data and evaluated confidence in anticipated treatment effects according to the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach. We identified 20 eligible observational studies and 1 eligible randomized controlled trial. According to low or very low quality evidence, the effect of MAP support on neurological recovery after acute traumatic spinal cord injury is uncertain, and the use of vasopressors to support MAP may be associated with increased rates of predominantly cardiac adverse events. Increased SCPP appears likely to be associated with improved neurological recovery, but SCPP monitoring via intradural catheters at the anatomical site of injury may involve increased risks of cerebrospinal fluid leakage requiring revision surgery or pseudomeningocele. No study directly compared the effects of specific MAP goal ranges, SCPP ranges, SCPP monitoring techniques, or durations of treatment. Very low quality evidence suggests that norepinephrine may have less risk of adverse events than dopamine. The current literature is insufficient to make strong recommendations about interventions to support spinal cord perfusion via MAP or SCPP goals in patients with acute traumatic spinal cord injuries. Data are compatible with a variety of treatment decisions, and individualized approaches may be optimal. Further investigation to clarify the risks, benefits, and alternatives to MAP or SCPP support in this population is warranted.

Predictors of Intraspinal Pressure and Optimal Cord Perfusion Pressure After Traumatic Spinal Cord Injury

Background/Objectives

We recently developed techniques to monitor intraspinal pressure (ISP) and spinal cord perfusion pressure (SCPP) from the injury site to compute the optimum SCPP (SCPP_opt) in patients with acute traumatic spinal cord injury (TSCI). We hypothesized that ISP and SCPP_opt can be predicted using clinical factors instead of ISP monitoring.

Methods

Sixty-four TSCI patients, grades A–C (American spinal injuries association Impairment Scale, AIS), were analyzed. For 24 h after surgery, we monitored ISP and SCPP and computed SCPP_opt (SCPP that optimizes pressure reactivity). We studied how well 28 factors correlate with mean ISP or SCPP_opt including 7 patient-related, 3 injury-related, 6 management-related, and 12 preoperative MRI-related factors.

Results

All patients underwent surgery to restore normal spinal alignment within 72 h of injury. Fifty-one percentage had U-shaped sPRx versus SCPP curves, thus allowing SCPP_opt to be computed. Thirteen percentage, all AIS grade A or B, had no U-shaped sPRx versus SCPP curves. Thirty-six percentage (22/64) had U-shaped sPRx versus SCPP curves, but the SCPP did not reach the minimum of the curve, and thus, an exact SCPP_opt could not be calculated. In total 5/28 factors were associated with lower ISP: older age, excess alcohol consumption, nonconus medullaris injury, expansion duroplasty, and less intraoperative bleeding. In a multivariate logistic regression model, these 5 factors predicted ISP as normal or high with 73% accuracy. Only 2/28 factors correlated with lower SCPP_opt: higher mean ISP and conus medullaris injury. In an ordinal multivariate logistic regression model, these 2 factors predicted SCPP_opt as low, medium–low, medium–high, or high with only 42% accuracy. No MRI factors correlated with ISP or SCPP_opt.

Conclusions

Elevated ISP can be predicted by clinical factors. Modifiable factors that may lower ISP are: reducing surgical bleeding and performing expansion duroplasty. No factors accurately predict SCPP_opt; thus, invasive monitoring remains the only way to estimate SCPP_opt.

Electronic supplementary material

The online version of this article (10.1007/s12028-018-0616-7) contains supplementary material, which is available to authorized users.

Hypoxia preconditioning promotes bone marrow mesenchymal stem cells survival by inducing HIF-1α in injured neuronal cells derived exosomes culture system

Bone marrow derived stem cells (BMSCs) transplantation are viewed as a promising therapeutic candidate for spinal cord injury (SCI). However, the inflammatory microenvironment in the spinal cord following SCI limits the survival and efficacy of transplanted BMSCs. In this study, we investigate whether injured neuronal cells derived exosomes would influence the survival of transplanted BMSCs after SCI. In order to mimic the microenvironment in SCI that the neuronal cells or transplanted BMSCs suffer in vivo, PC12 cells conditioned medium and PC12 cell’s exosomes collected from H₂O₂-treated PC12 cell’s culture medium were cultured with BMSCs under oxidative stress in vitro. PC12 cells conditioned medium and PC12 cell’s exosomes significantly accelerated the apoptosis of BMSCs induced by H₂O₂. Moreover, the cleaved caspase-3, cytochrome (Cyt) C, lactate dehydrogenase (LDH) releases, and apoptotic percentage were increased, and the ratio of Bcl-2/Bax and cell viability were decreased. Inhibition of exosome secretion via Rab27a small interfering RNA prevented BMSCs apoptosis in vitro. In addition, hypoxia-preconditioned promoted the survival of BMSCs under oxidative stress both in vivo after SCI and in vitro. Our results also indicate that HIF-1α plays a central role in the survival of BMSCs in hypoxia pretreatment under oxidative stress conditions. siRNA-HIF-1α increased apoptosis of BMSCs; in contrast, HIF-1α inducer FG-4592 attenuated apoptosis of BMSCs. Taken together, we found that the injured PC12 cells derived exosomes accelerate BMSCs apoptosis after SCI and in vitro, hypoxia pretreatment or activating expression of HIF-1α to be important in the survival of BMSCs after transplantation, which provides a foundation for application of BMSCs in therapeutic potential for SCI.

Prophylactic enlargement of the thecal sac volume by spinal expansion duroplasty in patients with unresectable malignant intramedullary tumors and metastases prior to radiotherapy

Unresectable malignant intramedullary tumors and metastases usually require radiotherapy which intensifies spinal cord edema and might result in neurological decline. Spinal expansion duroplasty before radiotherapy enlarges the intrathecal volume and might thus prevent neurological deficits. The study aims to evaluate the clinical course of patients undergoing expansion duroplasty. This retrospective analysis (2007-2016) included all patients with unresectable intramedullary tumors who underwent spinal expansion duroplasty. To assess the degree of preoperative cord enlargement, we calculated the "diameter ratio": diameter of the spinal cord below and above the tumor / diameter of the tumor × 2. The presence of perimedullary cerebrospinal fluid (CSF) at the affected levels was analyzed on the preoperative magnetic resonance imaging (MRI). We recorded the occurrence of neurological deficits, wound breakdown, and CSF fistula. We screened 985 patients, 11 of which were included. Eight patients had an intramedullary metastasis, three patients a spinal malignant glioma. A diameter ratio ≤ 0.8 representing a significant preoperative intramedullary enlargement was seen in 10 cases (90.9%). Postoperative imaging was available in 9 patients, demonstrating successful decompression in 8 of the 9 patients (88.9%). The postoperative course was uneventful in 9 patients (81.8%). Mean overall survival was 13.4 (SD 16.2) months. Spinal expansion duroplasty prior to radiotherapy is a previously undescribed concept. Despite neoadjuvant radiation, no wound breakdown or CSF fistula occurred. In unresectable intramedullary tumors and metastases, spinal expansion duroplasty seems to be a safe procedure with the potential to prevent neurological decline due to radiation-induced cord swelling.

Novel multi-drug delivery hydrogel using scar-homing liposomes improves spinal cord injury repair

Proper selection and effective delivery of combination drugs targeting multiple pathophysiological pathways key to spinal cord injury (SCI) hold promise to address the thus far scarce clinical therapeutics for improving recovery after SCI. In this study, we aim to develop a clinically feasible way for targeted delivery of multiple drugs with different physiochemical properties to the SCI site, detail the underlying mechanism of neural recovery, and detect any synergistic effect related to combination therapy.

Methods: Liposomes (LIP) modified with a scar-targeted tetrapeptide (cysteine-alanine-glutamine-lysine, CAQK) were first constructed to simultaneously encapsulate docetaxel (DTX) and brain-derived neurotrophic factor (BDNF) and then were further added into a thermosensitive heparin-modified poloxamer hydrogel (HP) with affinity-bound acidic fibroblast growth factor (aFGF-HP) for local administration into the SCI site (CAQK-LIP-GFs/DTX@HP) in a rat model. In vivo fluorescence imaging was used to examine the specificity of CAQK-LIP-GFs/DTX binding to the injured site. Multiple comprehensive evaluations including biotin dextran amine anterograde tracing and magnetic resonance imaging were used to detect any synergistic effects and the underlying mechanisms of CAQK-LIP-GFs/DTX@HP both in vivo (rat SCI model) and in vitro (primary neuron).

Results: The multiple drugs were effectively delivered to the injured site. The combined application of GFs and DTX supported neuro-regeneration by improving neuronal survival and plasticity, rendering a more permissive extracellular matrix environment with improved regeneration potential. In addition, our combination therapy promoted axonal regeneration via moderation of microtubule function and mitochondrial transport along the regenerating axon.

Conclusion: This novel multifunctional therapeutic strategy with a scar-homing delivery system may offer promising translational prospects for the clinical treatment of SCI.

Recent update on basic mechanisms of spinal cord injury

Spinal cord injury (SCI) is a life-shattering neurological condition that affects between 250,000 and 500,000 individuals each year with an estimated two to three million people worldwide living with an SCI-related disability. The incidence in the USA and Canada is more than that in other countries with motor vehicle accidents being the most common cause, while violence being most common in the developing nations. Its incidence is two- to fivefold higher in males, with a peak in younger adults. Apart from the economic burden associated with medical care costs, SCI predominantly affects a younger adult population. Therefore, the psychological impact of adaptation of an average healthy individual as a paraplegic or quadriplegic with bladder, bowel, or sexual dysfunction in their early life can be devastating. People with SCI are two to five times more likely to die prematurely, with worse survival rates in low- and middle-income countries. This devastating disorder has a complex and multifaceted mechanism. Recently, a lot of research has been published on the restoration of locomotor activity and the therapeutic strategies. Therefore, it is imperative for the treating physicians to understand the complex underlying pathophysiological mechanisms of SCI.

Clinical Trials in Traumatic Spinal Cord Injury

Traumatic spinal cord injury (SCI) results in impaired neurologic function that for many individuals is permanent and significantly impacts health, function, quality of life, and life expectancy. Many efforts have been taken to develop effective treatments for SCI; nevertheless, proven therapies targeting neurologic regeneration and functional recovery have been limited. Existing therapeutic approaches, including early surgery, strict blood pressure control, and consideration of treatment with steroids, remain debated and largely focus on mitigating secondary injury after the primary trauma has occurred. Today, there is more research being performed in SCI than ever before. Current clinical trials are exploring pharmacologic, cell-based, physiologic, and rehabilitation approaches to reduce secondary injury and also overcome barriers to neurorecovery. In the future, it is likely that tailored treatments combining many of these strategies will offer significant benefits for persons with SCI. This article aims to review key past, current and emerging neurologic and rehabilitation therapeutic approaches for adults with traumatic SCI.

Method of Decompression by durotomy and duroplasty for cervical spinal cord injury in patients without fracture or dislocation

Introduction:

We developed the method of cervical spinal cord decompression through durotomy followed by duroplasty and analyzed its efficacy.

Purpose:

To develop a tactic of decompression durotomy and duroplasty for the treatment of severe spinal cord injury(SCI) with extensive edema of the spinal cord and without intramedullary hematoma, and to demonstrate the effectiveness of this method.

Methods:

From October 2016 to January 2018, 17 decompression operations were performed in the cervical spine in patients with SCI. Decompression laminectomy was done without durotomy in the first group of patients. In the second group, duroplasty of the spinal cord was performed after decompression durotomy. A total of 17 patients, 16 males (94%) and 1 female (6%), were operated on (ages from 32 to 66 years). The patients were divided into two groups: a control group and an experimental group. We used the ASIA scale for assessing the patients. The mean follow up time is 12 months (8−24 months).

Results:

The first group, i.e., the control group consisted of 10 patients who underwent decompression laminectomy without durotomy. The second group, i.e., the experimental group consisted of 7 patients who underwent durotomy followed by duroplasty. In this group, the positive dynamics were observed in 6 patients. Out of 2 patients with ASIA grade “A”, one showed improvement to ASIA grade “C”, and one improved to ASIA “D”. Two patients with ASIA grade “B” showed recovery to ASIA “D”. Two patients with ASIA grade “C” improved to grade “D” while one patient showed no change from ASIA “C”. Durotomy and duroplasty was effective in the experimental group.

Conclusion:

The performance of durotomy and duroplasty is an efficient method for the full-scale decompression of the spinal cord and the prevention of edema. This method aims at decreasing intraspinal pressure, as well as preventing ischemia and apoptosis, which is possible for the prevention and treatment of the spinal cord compartment syndrome or spinal cord intramedullary hypertension.

Multicenter, randomized, double-blind placebo-control intramedullary decompression for acute complete spinal cord contusion injury

Introduction:

Spinal cord injury is one of the main causes of severe neurological trauma and disability. Intramedullary decompression of acute spinal cord contusion in acute phase is one of the important therapeutic exploration methods. Due to the lack of multicenter, randomized, double-blind, placebo-controlled clinical studies, true effect of this treatment remains controversial.

Objective of the study:

This design of the study is to explore the safety and neurorestorative effects of intramedullary decompression for acute complete spinal cord contusion injury.

Design of the study:

We design the prospective, multicenter, randomized, double- blind placebo-controlled trial (MRDPT) for acute (less than 24 hours after injury) spinal cord contusion injury. Sixty patients with acute complete spinal cord contusion injury (20 in cervical 4 to thoracic 1, 20 in thoracic 2 to thoracic 9, and 20 in thoracic 10 to lumbar vertebra 1) are selected according to the selected conditions. All patients receive conventional treatments such as reduction and fixation of spinal fractures and/or spinal spondylolisthesis, bone external decompression relieves spinal cord compression. At the same time, group A (n = 30, 10 of each segment group) undergoes intramedullary decompression surgery and group B (n = 30) does not undergo intramedullary decompression. All relevant functional changes before, after, and during the follow-up period are recorded to ensure objective evaluation of the results of the treatment.

Ethics and dissemination:

The clinical study protocol and consent form were approved by China Branch of International Association of Neurorestoratology and the ethics committees of the hospitals which join this trial. Registration No. of this study is ChiCTR1800020458. Findings will be published in peer-reviewed journals.