REVIEW OF TREATMENT TRIALS IN HUMANSPINAL CORD INJURY

Tracing the evolving dynamics and research hotspots of spinal cord injury and surgical decompression from 1975 to 2024: a bibliometric analysis

Background

Exploration of the benefits and timing of surgical decompression in spinal cord injury (SCI) has been a research hotspot. However, despite the higher volume and increasing emphasis on quality there remains no bibliometric view on SCI and surgical decompression. In this study, we aimed to perform bibliometric analysis to reveal the core countries, affiliations, journals, authors, and developmental trends in SCI and surgical decompression across the past 50 years.

Methods

Articles and reviews were retrieved from web of science core collection between 1975 and 2024. The bibliometrix package in R was used for data analysis and visualizing.

Results

A total of 8,688 documents were investigated, indicating an ascending trend in annual publications. The USA and China played as the leaders in scientific productivity. The University of Toronto led in institutional productions. Core authors, such as Michael G. Fehlings, showed high productivity, and occasional authors showed widespread interests. Core journals like Spine and Spinal Cord served as beacons in this field. The interaction of core authors and international collaboration accentuated the cross-disciplinary feature of the field. Prominent documents emphasized the clinical significance of early decompression in 24 h post SCI.

Conclusion

Based on comprehensive bibliometric analysis and literature review, we identified the hotspots and future directions of this field: (1) further investigation into the molecular and cellular mechanisms to provide pre-clinical evidence for biological effects of early surgical decompression in SCI animal models; (2) further evaluation and validation of the optimal time window of surgical decompression based on large cohort, considering the inherent heterogeneity of subpopulations in complicated immune responses post SCI; (3) further exploration on the benefits of early decompression on the neurological, functional, and clinical outcomes in acute SCI; (4) evaluation of the optimal surgical methods and related outcomes; (5) applications of artificial intelligence-based technologies in spinal surgical decompression.

Neuroprotective Effects of Coenzyme Q10 and Ozone Therapy on Experimental Traumatic Spinal Cord Injuries in Rats

OBJECTIVE

This study investigates the neuroprotective effects and functional recovery potential of Coenzyme Q10 (CoQ10) and ozone therapy in spinal cord injury (SCI).

MATERIAL AND METHODS

In this study, 40 female Sprague-Dawley rats were divided into 5 groups of 8. Surgical procedures induced spinal cord trauma in all groups, except the control group. The ozone group received 0.7 mg/kg rectal ozone daily for 7 days, starting 1 hour postspinal cord trauma. The CoQ10 group was administered 120 mg/kg CoQ10 orally once daily for 7 days, beginning 24 hours prior to trauma. The CoQ10 + ozone group received both treatments. Examinations included a modified Tarlov scale and inclined plane test on days 1, 3, 5, and 7. Malondialdehyde (MDA) analysis was conducted on serum samples, and assessments of caspase-3, Bcl-2, and Bax levels were performed on tissue samples. Additionally, a comprehensive examination analyzed histopathological and ultrastructural changes.

RESULTS

After SCI, there was a statistically significant increase in serum MDA, tissue caspase-3, and Bax levels (MDA P < 0.001, caspase-3 P < 0.001, Bax P = 0.003). In the CoQ10 + ozone group, serum MDA (P = 0.002), tissue caspase-3 (P = 0.001), and Bax (P = 0.030) levels were significantly lower compared to the trauma group. Tissue Bcl-2 levels were also significantly higher (P = 0.019). The combined treatment group demonstrated improved histopathological, ultrastructural, and neurological outcomes.

CONCLUSIONS

This study shows that CoQ10 + ozone therapy in traumatic SCI demonstrates neuroprotective effects via antioxidant and antiapoptotic mechanisms. The positive effects on functional recovery are supported by data from biochemical, histopathological, ultrastructural, and neurological examinations.

Neurophysiological, histological, and behavioral characterization of animal models of distraction spinal cord injury: a systematic review

Distraction spinal cord injury is caused by some degree of distraction or longitudinal tension on the spinal cord and commonly occurs in patients who undergo corrective operation for severe spinal deformity. With the increased degree and duration of distraction, spinal cord injuries become more serious in terms of their neurophysiology, histology, and behavior. Very few studies have been published on the specific characteristics of distraction spinal cord injury. In this study, we systematically review 22 related studies involving animal models of distraction spinal cord injury, focusing particularly on the neurophysiological, histological, and behavioral characteristics of this disease. In addition, we summarize the mechanisms underlying primary and secondary injuries caused by distraction spinal cord injury and clarify the effects of different degrees and durations of distraction on the primary injuries associated with spinal cord injury. We provide new concepts for the establishment of a model of distraction spinal cord injury and related basic research, and provide reference guidelines for the clinical diagnosis and treatment of this disease.

Intrathecal injection of human placental mesenchymal stem cells derived exosomes significantly improves functional recovery in spinal cord injured rats

BACKGROUND

Spinal cord injury (SCI) due to lack of restoration of damaged neuronal cells is associated with sensorimotor impairment. This study was focused on using the human placental mesenchymal stem cells- exosome (HPMSCs- Exosomes) in an animal model of severe SCI under myelogram procedure.

METHODS AND RESULTS

Intrathecal injection of exosomes was performed in the acute phase of SCI in female rats. The improved functional recovery of the animals was followed for 6 weeks in control (saline, n = 6) and HPMSCs- EXO (HPMSCs-Exosomes, n = 6) groups. Pathological changes and glial scar size were evaluated. The Immunohistochemistry (IHC) of GFAP and NF200 factors as well as the apoptosis assay was investigated in the tissue samples from the injury site. The results demonstrated that HPMSCs-exosomes can improve motor function by attenuating apoptosis of neurons at the injury site, decreasing GFAP expression and increasing NF200 in the HPMSCs-EXO group. Also, HPMSCs-exosomes by preventing the formation of cavities causes preservation of tissue in SCI rats.

CONCLUSIONS

These findings demonstrate the effectiveness of HPMSC-Exosomes as a therapeutic method to improve functional recovery, reduce pathological changes associated with injury, and prevent chronicity after SCI. The neuroprotective and anti-apoptotic potential of HPMSCs- Exosomes may be a promising therapeutic approach for SCI. Another result was the importance of intrathecal injection of exosomes in the acute phase, which accelerated the healing process. Furthermore, the myelogram can be a feasible and suitable method to confirm the accuracy of intrathecal injection and examine the subarachnoid space in the laboratory animals.

Stem cells in central nervous system diseases: Promising therapeutic strategies

Central nervous system (CNS) diseases are a leading cause of death and disability. Due to CNS neurons have no self-renewal and regenerative ability as they mature, their loss after injury or disease is irreversible and often leads to functional impairments. Unfortunately, therapeutic options for CNS diseases are still limited, and effective treatments for these notorious diseases are warranted to be explored. At present, stem cell therapy has emerged as a potential therapeutic strategy for improving the prognosis of CNS diseases. Accumulating preclinical and clinical evidences have demonstrated that multiple molecular mechanisms, such as cell replacement, immunoregulation and neurotrophic effect, underlie the use of stem cell therapy for CNS diseases. However, several issues have yet to be addressed to support its clinical application. Thus, this review article aims to summarize the role and underlying mechanisms of stem cell therapy in treating CNS diseases. And it is worthy of further evaluation for the potential therapeutic applications of stem cell treatment in CNS disease.

History and Accomplishments of the North American Clinical Trials Network for Spinal Cord Injury, 2004-2022

This is a historical account of the origin and accomplishments of the North American Clinical Trials Network (NACTN) for traumatic spinal cord injury (SCI), which was established in 2004 by Christopher Reeve and Robert Grossman. Christopher Reeve was an actor who became quadriplegic and started the Christopher & Dana Reeve Foundation (CDRF), and Robert Grossman was a neurosurgeon experienced in neurotrauma and a university professor in Houston. NACTN has member investigators at university and military centers in North America and has contributed greatly to the improvement of care, primarily acute care, of patients sustaining traumatic SCI. Its accomplishments are a clinical registry database of >1000 acute SCI patients documenting the care pathways, including complications. NACTN has assessed the effectiveness of treatment, including pharmacotherapy and the role and timing of surgery, and has also identified barriers to early surgery. The principal focus has been on improving neurological recovery. NACTN has trained many SCI practitioners and has collaborated with other SCI networks and organizations internationally to promote the care of SCI patients.

Pediatric spinal cord injury with radiographic abnormality: the Beijing experience

BACKGROUND CONTEXT

Spinal cord injury (SCI) without radiographic abnormality (SCIWORA) is a syndrome that usually occurs in children primarily because of the unique biomechanics of the pediatric spine. We recently found that the histopathological and behavioral effects of SCI with radiographic abnormality (SCIWRA) and SCIWORA are very different from each other in animal models. Although numerous studies were conducted to understand the epidemiological and clinical characteristics of the overall pediatric SCI population and the pediatric SCIWORA population, the characteristics of the pediatric SCIWRA population and their differences from those of the SCIWORA population are poorly understood.

PURPOSE

To describe the epidemiology and clinical outcomes of pediatric patients with SCIWRA and their differences from those with SCIWORA.

STUDY DESIGN/SETTING

Retrospective study.

PATIENT SAMPLE

A total of 47 pediatric SCIWRA patients.

OUTCOME MEASURES

Epidemiological characteristics, injury severities, functional deficits, and management and recovery outcomes.

METHODS

Review of all cases with SCIWRA at Beijing Children's Hospital between July 2007 and December 2019 and comparison between the present data and our previous SCIWORA data.

RESULTS

Of the 187 pediatric SCI patients, 47 had SCIWRA (age: 7.06 ± 3.75 years, male-to-female ratio: 3:2). Main causes of SCIWRA were fall (38%) and traffic accidents (38%). Lesions were often located at multiple levels (62%). Incubation period was 3 ± 18 hours. According to the American Spinal Injury Association impairment scale (AIS), many SCIWRA patients had incomplete impairment (AIS B, 9%; AIS C, 9%; AIS D, 32%). Specifically, many of them had abnormal upper and lower limb muscle powers (55% and 60%), upper and lower limb muscle tones (34% and 49%), sensation (38%), and knee, ankle, and abdominal reflexes (47%, 34%, and 36%). 72% of SCIWRA patients were treated with methylprednisolone, dexamethasone, or both. 81% of them showed neurological improvement before discharge. There was no association between corticosteroid therapy and neurological improvement. Moreover, functional outcomes of their upper and lower limb muscle powers were significantly associated with functional outcomes of their upper and lower limb muscle tones (p < 0.01), respectively. In comparison to the SCIWRA population, the SCIWORA population had a higher ratio of younger and female patients of sports-related thoracic injuries with long incubation period leading to lower-body deficits and complete impairment (p<0.05 or p<0.01). Despite all the differences, their neurological improvement was similar (p>0.05).

CONCLUSIONS

Demographic differences exist in the SCIWRA population. Corticosteroids do not appear to be effective in the different types of pediatric SCI. Limb muscle tone may be used to evaluate the functional status of limb muscle power. The epidemiological and clinical characteristics of SCIWRA and SCIWORA are very different from each other. It is important to formulate tailor-made prevention, evaluation, and management strategies for the pediatric population to optimize the SCI outcomes.

Early Predictors and Outcomes of American Spinal Injury Association Conversion at Discharge in Surgical and Nonsurgical Management of Sports-Related Spinal Cord Injury

OBJECTIVE

This study aims to evaluate the rate of improvement in neurologic recovery of patients with sports-related spinal cord injury (SRSCI) who had surgical intervention (SS) and those who did not (NSS). We aimed to 1) evaluate the rate of American Spinal Injury Association (ASIA) conversion in patients with and without surgery, and 2) assess predictors of conversion in ASIA grade.

METHODS

The National Spinal Cord Injury Model Systems Database (SCIMS) was used from 1973 to 2016. Patients with SRSCI were included. The primary outcome was rate of conversion in ASIA grade. Multivariate logistic regression was performed with separate subgroup analysis on patients with cervical injury (represented by odds ratio [OR]; 95% confidence interval [CI]).

RESULTS

A total of 1647 patients had SRSCI with 1502 (91%) SSs. Most patients (88%) were male, white (87%), and between the ages of 15 and 29 years (63%). Patients undergoing SS had significantly longer inpatient rehabilitation length of stay (LOS) (P < 0.001) and a more patients undergoing SS had complete motor or sensory loss compared with the NSS group. Multivariate logistic regression showed that injury at the thoracic level (OR, 0.41; 95% CI, 0.21-0.78), age 15-29 years (OR, 0.44; 95% CI, 0.20-0.97]), water-based injury (OR, 0.45; 95% CI, 0.21-0.95), and ASIA impairment grades of B, C, and D at admission were significantly associated with ASIA SCORE conversion.

CONCLUSIONS

We found that patients undergoing SS had longer LOS and a higher prevalence of complete injuries. Surgical intervention was not associated with conversion in ASIA grade to an improved status at time of discharge in a large cohort of patients with SRSCI and in a subcohort of patients with cervical SRSCI.

Identification of injury type using somatosensory and motor evoked potentials in a rat spinal cord injury model

The spinal cord is at risk of injury during spinal surgery. If intraoperative spinal cord injury is identified early, irreversible impairment or loss of neurological function can be prevented. Different types of spinal cord injury result in damage to different spinal cord regions, which may cause different somatosensory and motor evoked potential signal responses. In this study, we examined electrophysiological and histopathological changes between contusion, distraction, and dislocation spinal cord injuries in a rat model. We found that contusion led to the most severe dorsal white matter injury and caused considerable attenuation of both somatosensory and motor evoked potentials. Dislocation resulted in loss of myelinated axons in the lateral region of the injured spinal cord along the rostrocaudal axis. The amplitude of attenuation in motor evoked potential responses caused by dislocation was greater than that caused by contusion. After distraction injury, extracellular spaces were slightly but not significantly enlarged; somatosensory evoked potential responses slightly decreased and motor evoked potential responses were lost. Correlation analysis showed that histological and electrophysiological findings were significantly correlated and related to injury type. Intraoperative monitoring of both somatosensory and motor evoked potentials has the potential to identify iatrogenic spinal cord injury type during surgery.

Porcine spinal cord injury model for translational research across multiple functional systems

Animal models are necessary to identify pathological changes and help assess therapeutic outcomes following spinal cord injury (SCI). Small animal models offer value in research in terms of their easily managed size, minimal maintenance requirements, lower cost, well-characterized genomes, and ability to power research studies. However, despite these benefits, small animal models have neurologic and anatomical differences that may influence translation of results to humans and thus limiting the success of their use in preclinical studies as a direct pipeline to clinical studies. Large animal models, offer an attractive intermediary translation model that may be more successful in translating to the clinic for SCI research. This is largely due to their greater neurologic and anatomical similarities to humans. The physical characteristics of pig spinal cord, gut microbiome, metabolism, proportions of white to grey matter, bowel anatomy and function, and urinary system are strikingly similar and provide great insight into human SCI conditions. In this review, we address the variety of existing porcine injury models and their translational relevance, benefits, and drawbacks in modeling human systems and functions for neurophysiology, cardiovascular, gastrointestinal and urodynamic functions.

A survival model of thoracic contusion spinal cord injury in the domestic pig

Spinal cord injury (SCI) frequently results in motor, sensory and autonomic dysfunction for which there is currently no cure. Recent preclinical and clinical research has led to promising advances in treatment; however, therapeutics indicating promise in rodents have not translated successfully in human trials, likely due, in part, to gross anatomical and physiological differences between the species. Therefore, large animal models of SCI may facilitate the study of secondary injury processes that are influenced by scale, and assist the translation of potential therapeutic interventions. The aim of this study was to characterize two severities of thoracic contusion SCI in female domestic pigs, measuring motor function and spinal cord lesion characteristics, over two weeks post-SCI. A custom instrumented weight drop injury device was used to release a 50 g impactor from 10 cm (n=3) or 20 cm (n=7) onto the exposed dura, to induce a contusion at the T10 thoracic spinal level. Hind limb motor function was assessed at 8 and 13 days post-SCI using a 10-point scale. Volume and extent of lesion-associated signal hyperintensity in T2-weighted magnetic resonance (MR) images was assessed at 3, 7 and 14 days post-injury. Animals were transcardially perfused at 14 days post-SCI and spinal cord tissue was harvested for histological analysis. Bowel function was retained in all animals and transient urinary retention occurred in two animals after catheter removal. All animals displayed hind limb motor deficits. Animals in the 10 cm group demonstrated some stepping and weight bearing and scored a median 2-3 points higher on the 10-point motor function scale at 8 and 13 days post-SCI, than the 20 cm group. Histological lesion volume was 20 % greater, and 30 % less white matter was spared, in the 20 cm group than in the 10 cm group. The MR signal hyperintensity in the 20 cm injury group had a median cranial-caudal extent approximately 1.5 times greater than the 10 cm injury group at all three time points, and median volumes 1.8, 2.5 and 4.5 times greater at day 3, 7 and 14 post-injury, respectively. Regional differences in axonal injury were observed between groups, with amyloid precursor protein immunoreactivity greatest in the 20 cm group in spinal cord sections adjacent the injury epicenter. This study demonstrated graded injuries in a domestic pig strain, with outcome measures comparable to miniature pig models of contusion SCI. The model provides a vehicle for the study of SCI and potential treatments, particularly where miniature pig strains are not available and/or where small animal models are not appropriate for the research question.

Clinical translation of stem cell therapy for spinal cord injury still premature: results from a single-arm meta-analysis based on 62 clinical trials

BACKGROUND

How much scientific evidence is there to show that stem cell therapy is sufficient in preclinical and clinical studies of spinal cord injury before it is translated into clinical practice? This is a complicated problem. A single, small-sample clinical trial is difficult to answer, and accurate insights into this question can only be given by systematically evaluating all the existing evidence.

METHODS

The PubMed, Ovid-Embase, Web of Science, and Cochrane databases were searched from inception to February 10, 2022. Two independent reviewers performed the literature search, identified and screened the studies, and performed a quality assessment and data extraction.

RESULTS

In total, 62 studies involving 2439 patients were included in the analysis. Of these, 42 were single-arm studies, and 20 were controlled studies. The meta-analysis showed that stem cells improved the ASIA impairment scale score by at least one grade in 48.9% [40.8%, 56.9%] of patients with spinal cord injury. Moreover, the rate of improvement in urinary and gastrointestinal system function was 42.1% [27.6%, 57.2%] and 52.0% [23.6%, 79.8%], respectively. However, 28 types of adverse effects were observed to occur due to stem cells and transplantation procedures. Of these, neuropathic pain, abnormal feeling, muscle spasms, vomiting, and urinary tract infection were the most common, with an incidence of > 20%. While no serious adverse effects such as tumorigenesis were reported, this could be due to the insufficient follow-up period.

CONCLUSIONS

Overall, the results demonstrated that although the efficacy of stem cell therapy is encouraging, the subsequent adverse effects remain concerning. In addition, the clinical trials had problems such as small sample sizes, poor design, and lack of prospective registration, control, and blinding. Therefore, the current evidence is not sufficiently strong to support the clinical translation of stem cell therapy for spinal cord injury, and several problems remain. Additional well-designed animal experiments and high-quality clinical studies are warranted to address these issues.

Porcine Model of Spinal Cord Injury: A Systematic Review

Spinal cord injury (SCI) is a devastating disease with limited effective treatment options. Animal paradigms are vital for understanding the pathogenesis of SCI and testing potential therapeutics. The porcine model of SCI is increasingly favored because of its greater similarity to humans. However, its adoption is limited by the complexities of care and range of testing parameters. Researchers need to consider swine selection, injury method, post-operative care, rehabilitation, behavioral outcomes, and histology metrics. Therefore, we systematically reviewed full-text English-language articles to evaluate study characteristics used in developing a porcine model and summarize the interventions that have been tested using this paradigm. A total of 63 studies were included, with 33 examining SCI pathogenesis and 30 testing interventions. Studies had an average sample size of 15 pigs with an average weight of 26 kg, and most used female swine with injury to the thoracic cord. Injury was most commonly induced by weight drop with compression. The porcine model is amenable to testing various interventions, including mean arterial pressure augmentation (n = 7), electrical stimulation (n = 6), stem cell therapy (n = 5), hypothermia (n = 2), biomaterials (n = 2), gene therapy (n = 2), steroids (n = 1), and nanoparticles (n = 1). It is also notable for its clinical translatability and is emerging as a valuable pre-clinical study tool. This systematic review can serve as a guideline for researchers implementing and testing the porcine SCI model.

Pragmatism in Pediatric Neurosurgery: More Than a Pipe Dream? A Systematic Literature Review and Analysis

BACKGROUND

Classic randomized controlled trials (RCTs) form the cornerstone for medical guidelines and protocols. However, in neurosurgery, RCTs are not always applicable to everyday clinical practice. Pragmatic controlled trials aim to incorporate real-life data with the preservation of the methodologic quality. This study is a systematic literature review of all pediatric neurosurgical RCTs published between 2000 and 2020 and an analysis of their pragmatism.

METHODS

An electronic database search was performed in PubMed, EMBASE, and the Cochrane Library to identify all relevant trials. Pragmatism was evaluated retrospectively on 9 domains: eligibility, recruitment, setting, organization, flexibility (delivery and adherence), follow-up, primary outcome, and primary analysis.

RESULTS

Of the 1862 studies included, 15 met the inclusion criteria. On average, studies scored between equally pragmatic/explanatory and rather pragmatic (M = 3.59, standard deviation [SD] = 0.56). Lowest ratings were seen for setting (M = 2.80, SD = 1.66) and eligibility (M = 3.20, SD = 1.66). Highest scores of pragmatism were given to analysis (M = 4.67, SD = 0.82) and intervention organization (M = 4.60, SD = 1.06). There was no significant difference between studies based on number of patients included, main subject, or publication year.

CONCLUSIONS

Pediatric neurosurgical RCTs scored reasonably well on overall pragmatism. In the future, there will be a greater need for pragmatic controlled trials in pediatric neurosurgery to bridge the divide between real-life data and reliable methodological quality. There is an opportunity to develop further applications of pragmatism tailored to surgical interventions.

Spinal Cord Injury: A Systematic Review and Network Meta-Analysis of Therapeutic Strategies Based on 15 Types of Stem Cells in Animal Models

Objective: The optimal therapeutic strategies of stem cells for spinal cord injury (SCI) are fully explored in animal studies to promote the translation of preclinical findings to clinical practice, also to provide guidance for future animal experiments and clinical studies.

Methods: PubMed, Web of Science, Embase, CNKI, Wangfang, VIP, and CBM were searched from inception to September 2021. Screening of search results, data extraction, and references quality evaluation were undertaken independently by two reviewers.

Results and Discussion: A total of 188 studies were included for data analysis. Results of traditional meta-analysis showed that all 15 diverse types of stem cells could significantly improve locomotor function of animals with SCI, and results of further network meta-analysis showed that adipose-derived mesenchymal stem cells had the greatest therapeutic potential for SCI. Moreover, a higher dose (≥1 × 106) of stem cell transplantation had better therapeutic effect, transplantation in the subacute phase (3–14 days, excluding 3 days) was the optimal timing, and intralesional transplantation was the optimal route. However, the evidence of current animal studies is of limited quality, and more high-quality research is needed to further explore the optimal therapeutic strategies of stem cells, while the design and implementation of experiments, as well as measurement and reporting of results for animal studies, need to be further improved and standardized to reduce the risk when the results of animal studies are translated to the clinic.

Systematic Review Registration: [website], identifier [registration number].

Therapeutic Effect of Exosomes Derived From Stem Cells in Spinal Cord Injury: A Systematic Review Based on Animal Studies

Objective

A systematic review of the role of stem cell-derived exosomes in repairing spinal cord injury (SCI) and the existing problems in animal experiments to provide a reference for better animal experiments and clinical studies in the future.

Method

Three electronic databases, namely PubMed, Web of Science, and Ovid-Embase were searched. The studies were retrieved from inception to October 2021. Two researchers independently screened the literature, extracted data, and evaluated the methodological quality based on the inclusion criteria.

Results and Discussion

Thirty-two studies were incorporated into the final analyses. Exosomes derived from stem cells could not only significantly improve the motor function of animals with SCI, but also significantly increase the expression of anti-inflammatory factors IL-4 and IL-10 and anti-apoptotic protein Bcl-2, while significantly lowering the pro-inflammatory factor IL-1β and TNF-α and the expression of the apoptotic protein BAX. However, the mechanism of exosome-mediated SCI repair, as well as the best source and dosage remain unknown. In addition, there are still some issues with the design, implementation, and reporting of animal experiments in the included studies. Therefore, future research should further standardize the implementation and reporting of animal studies and fully explore the best strategies for exosomes to repair SCI so as to promote the translation of preclinical research results to clinical research better and faster.

Recombinant Adenoviruses for Delivery of Therapeutics Following Spinal Cord Injury

The regeneration of nerve tissue after spinal cord injury is a complex and poorly understood process. Medication and surgery are not very effective treatments for patients with spinal cord injuries. Gene therapy is a popular approach for the treatment of such patients. The delivery of therapeutic genes is carried out in a variety of ways, such as direct injection of therapeutic vectors at the site of injury, retrograde delivery of vectors, and ex vivo therapy using various cells. Recombinant adenoviruses are often used as vectors for gene transfer. This review discusses the advantages, limitations and prospects of adenovectors in spinal cord injury therapy.

Early Decompression and Short Transport Time After Traumatic Spinal Cord Injury are Associated with Higher American Spinal Injury Association Impairment Scale Conversion

STUDY DEIGN

Retrospective cohort study.

OBJECTIVES

This retrospective cohort study aims to determine the association of early decompressive surgery and the impact of transport time on the neurological outcomes of traumatic spinal cord injury (tSCI) patients.

SUMMARY OF BACKGROUND DATA

tSCI is a catastrophic event that may result in permanent disability or loss of function. To date, there remains significant controversy over the optimal time for surgical decompression in tSCI patients. The aim of this study is to evaluate the neurological outcomes of tSCI patients undergoing early versus late surgical decompression and the impact of transport time on neurological outcomes.

METHODS

Data from 84 patients with tSCI requiring surgical decompression was collected. Regression analysis was used to establish time to decompression classification cutoffs. Patients were classified into the following subgroups: 0 to 12 or >12 hours as a factor of the total or admitting hospital time to decompression. The change in American Spinal Injury Association Impairment (AIS) Grade from admission to discharge was determined. Additionally, the effect of transport time on conversion of AIS grade was assessed as patients were grouped into transport times of <6 or >6 hours.

RESULT

Among the time to decompression subgroups there were no significant differences (P > 0.05) in confounding factors such as age, injury severity, and AIS grade. Patients who received decompression within 0 to 12 hours were associated with significantly (P < 0.0001) higher average improvements in ASIA grade (0.76). Patient transport times <6 hours were associated with significantly (P = 0.004) higher conversion of AIS grade to less impaired states.

CONCLUSION

The present study suggests an association of decompression within 12 hours and short transport times (<6 hours) with significant improvements in neurological outcomes.Level of Evidence: 4.

How to generate graded spinal cord injuries in swine - tools and procedures

Spinal cord injury (SCI) is a medically, psychologically and socially disabling condition. A large body of our knowledge on the basic mechanisms of SCI has been gathered in rodents. For preclinical validation of promising therapies, the use of animal models that are closer to humans has several advantages. This has promoted the more-intensive development of large-animal models for SCI during the past decade. We recently developed a multimodal SCI apparatus for large animals that generated biomechanically reproducible impacts in vivo. It is composed of a spring-load impactor and support systems for the spinal cord and the vertebral column. We now present the functional outcome of farm pigs and minipigs injured with different lesion strengths. There was a correlation between the biomechanical characteristics of the impact, the functional outcome and the tissue damage observed several weeks after injury. We also provide a detailed description of the procedure to generate such a SCI in both farm pigs and minipigs, in the hope to ease the adoption of the swine model by other research groups.

Local delivery of fingolimod through PLGA nanoparticles and PuraMatrix-embedded neural precursor cells promote motor function recovery and tissue repair in spinal cord injury

Spinal cord injury (SCI) is a devastating clinical problem that can lead to permanent motor dysfunction. Fingolimod (FTY720) is a sphingosine structural analogue, and recently, its therapeutic benefits in SCI have been reported. The present study aimed to evaluate the therapeutic efficacy of fingolimod-incorporated poly lactic-co-glycolic acid (PLGA) nanoparticles (nanofingolimod) delivered locally together with neural stem/progenitor cells (NS/PCs) transplantation in a mouse model of contusive acute SCI. Fingolimod was encapsulated in PLGA nanoparticles by the emulsion-evaporation method. Mouse NS/PCs were harvested and cultured from embryonic Day 14 (E14) ganglionic eminences. Induction of SCI was followed by the intrathecal delivery of nanofingolimod with and without intralesional transplantation of PuraMatrix-encapsulated NS/PCs. Functional recovery, injury size and the fate of the transplanted cells were evaluated after 28 days. The nanofingolimod particles represented spherical morphology. The entrapment efficiency determined by UV-visible spectroscopy was approximately 90%, and the drug content of fingolimod loaded nanoparticles was 13%. About 68% of encapsulated fingolimod was slowly released within 10 days. Local delivery of nanofingolimod in combination with NS/PCs transplantation led to a stronger improvement in neurological functions and minimized tissue damage. Furthermore, co-administration of nanofingolimod and NS/PCs not only increased the survival of transplanted cells but also promoted their fate towards more oligodendrocytic phenotype. Our data suggest that local release of nanofingolimod in combination with three-dimensional (3D) transplantation of NS/PCs in the acute phase of SCI could be a promising approach to restore the damaged tissues and improve neurological functions.

Novel Nanoliposomes Alleviate Contrast-Induced Nephropathy by Mediating Apoptosis Response in New Zealand Rabbits

The aim of this study was to test the preventive effects of nano liposomes against contrast-induced nephropathy (CIN) in New Zealand rabbits. Sixty New Zealand rabbits were randomly divided into four groups, with 15 rabbits in each group: control group, contrast group, hydration group and nano liposome group. Serum creatinine (Scr) and Blood Urea Nitrogen (BUN) were measured before and after injection of the contrast agent iopromide. Oxidative stress markers, such as superoxide dismutase (SOD) and malondialdehyde (MDA), and apoptosis markers, such as Bcl2-Associated X (Bax) and B-cell lymphoma-2 (Bcl-2), were measured by enzyme-linked immunosorbent assay (ELISA). Rabbits were killed 24 h after injection of the contrast medium and both kidneys were removed. Real-time Polymerase Chain Reaction (RT-PCR) and Western blot assays were performed in kidney tissue. Pathological changes were analyzed under the optical and electron microscope. Compared with the hydration group, the nano liposome group showed improved protection of renal function, with significantly different Scr and BUN levels, incidence of CIN, apoptosis index, RT-PCR and Western blot protein expression patterns. Under the optical and electron microscope, the renal injury in the nano liposome group was less than in the hydration group. However, based on SOD and MDA, there was no significant difference in oxidative stress when compared with the hydration group. Apoptosis is an important mechanism in CIN. Nano liposomes can prevent the occurrence of CIN by decreasing apoptosis, reducing damage to the kidney by the contrast agent.

The Natural History of Spinal Cord Injury

The natural history of spinal cord injury is in a state of flux. Our knowledge about the prevalence, epidemiology, and natural history spinal cord injury is in evolution. In this article, we summarize these considerations to provide a state-of-the-art synopsis of the neurologic outcomes of this condition.

Trajectory-Based Classification of Recovery in Sensorimotor Complete Traumatic Cervical Spinal Cord Injury

OBJECTIVE

To test the hypothesis that sensorimotor complete traumatic cervical spinal cord injury (SCI) is a heterogenous clinical entity comprising several subpopulations that follow fundamentally different trajectories of neurologic recovery.

METHODS

We analyzed demographic and injury data from 655 patients who were pooled from 4 prospective longitudinal multicenter studies. Group-based trajectory modeling was applied to model neurologic recovery trajectories over the initial 12 months postinjury and to identify predictors of recovery trajectories. Neurologic outcomes included upper extremity motor score, total motor scores, and American Spinal Injury Association Impairment Scale (AIS) grade improvement.

RESULTS

The analysis identified 3 distinct trajectories of neurologic recovery. These clinical courses included (1) marginal recovery trajectory, characterized by minimal or no improvement in motor strength or change in AIS grade status (remained grade A); (2) moderate recovery trajectory, characterized by low baseline motor scores that improved approximately 13 points or AIS conversion of 1 grade point; (3) good recovery trajectory, characterized by baseline motor scores in the upper quartile that improved to near maximum values within 3 months of injury. Patients following the moderate or good recovery trajectories were younger, had more caudally located injuries, had a higher degree of preserved motor and sensory function at baseline examination, and exhibited a greater extent of motor and sensory function in the zone of partial preservation.

CONCLUSION

Cervical complete SCI can be classified into one of 3 distinct subpopulations with fundamentally different trajectories of neurologic recovery. This study defines unique clinical phenotypes based on potential for recovery, rather than baseline severity of injury alone. This approach may prove beneficial in clinical prognostication and in the design and interpretation of clinical trials in SCI.

Selenium-Binding Protein 1 (SELENBP1) as Biomarker for Adverse Clinical Outcome After Traumatic Spinal Cord Injury

Introduction: Traumatic spinal cord injury (TSCI) presents a diagnostic challenge as it may have dramatic consequences for the affected patient. Additional biomarkers are needed for improved care and personalized therapy.

Objective: Serum selenium binding protein 1 (SELENBP1) has been detected in myocardial infarction, reflecting hypoxic tissue damage and recovery odds. As SELENBP1 is usually not detected in the serum of healthy subjects, we tested the hypothesis that it may become detectable in TSCI and indicate tissue damage and regeneration odds.

Methods: In this prospective observational study, patients with comparable injuries were allocated to three groups; vertebral body fractures without neurological impairment (control “C”), TSCI without remission (“G0”), and TSCI with signs of remission (“G1”). Consecutive serum samples were available from different time points and analyzed for SELENBP1 by sandwich immunoassay, for trace elements by X-ray fluorescence and for cytokines by multiplex immunoassays.

Results: Serum SELENBP1 was elevated at admission in relation to the degree of neurological impairment [graded as A, B, C, or D according to the American Spinal Injury Association (AISA) impairment scale (AIS)]. Patients with the most severe neurological impairment (classified as AIS A) exhibited the highest SELENBP1 concentrations (p = 0.011). During the first 3 days, SELENBP1 levels differed between G0 and G1 (p = 0.019), and dynamics of SELENBP1 correlated to monocyte chemoattractant protein 1, chemokine ligand 3 and zinc concentrations.

Conclusion: Circulating SELENBP1 concentrations are related to the degree of neurological impairment in TSCI and provide remission odds information. The tight correlation of SELENBP1 with CCL2 levels provides a novel link between Se metabolism and immune cell activation, with potential relevance for neurological damage and regeneration processes, respectively.

Noninvasive Neuroprosthesis Promotes Cardiovascular Recovery After Spinal Cord Injury

Spinal cord injury (SCI) leads to severe impairment in cardiovascular control, commonly manifested as a rapid, uncontrolled rise in blood pressure triggered by peripheral stimuli-a condition called autonomic dysreflexia. The objective was to demonstrate the translational potential of noninvasive transcutaneous stimulation (TCS) in mitigating autonomic dysreflexia following SCI, using pre-clinical evidence and a clinical case report. In rats with SCI, we show that TCS not only prevents the instigation of autonomic dysreflexia, but also mitigates its severity when delivered during an already-triggered episode. Furthermore, when TCS was delivered as a multisession therapy for 6 weeks post-SCI, the severity of autonomic dysreflexia was significantly reduced when tested in the absence of concurrent TCS. This treatment effect persisted for at least 1 week after the end of therapy. More importantly, we demonstrate the clinical applicability of TCS in treatment of autonomic dysreflexia in an individual with cervical, motor-complete, chronic SCI. We anticipate that TCS will offer significant therapeutic advantages, such as obviating the need for surgery resulting in reduced risk and medical expenses. Furthermore, this study provides a framework for testing the potential of TCS in improving recovery of other autonomic functions such lower urinary tract, bowel, and sexual dysfunction following SCI.

Blood Serum Cytokines in Patients with Subacute Spinal Cord Injury: A Pilot Study to Search for Biomarkers of Injury Severity

Background. Despite considerable interest in the search for a spinal cord injury (SCI) therapy, there is a critical need to develop a panel of diagnostic biomarkers to determine injury severity. In this regard, there is a requirement for continuing research into the fundamental processes of neuroinflammatory and autoimmune reactions in SCI, identifying changes in the expression of cytokines. Methods. In this pilot study, an extended multiplex analysis of the cytokine profiles in the serum of patients at 2 weeks post-SCI (n = 28) was carried out, together with an additional assessment of neuron-specific enolase (NSE) and vascular endothelial growth factor (VEGF) levels by enzyme-linked immunosorbent assay. A total of 16 uninjured subjects were enrolled as controls. Results. The data obtained showed a large elevation of IFNγ (>52 fold), CCL27 (>13 fold), and CCL26 (>8 fold) 2 weeks after SCI. The levels of cytokines CXCL5, CCL11, CXCL11, IL10, TNFα, and MIF were different between patients with baseline American Spinal Injury Association Impairment Scale (AIS) grades of A or B, whilst IL2 (>2 fold) and MIP-3a (>6 fold) were significantly expressed in the cervical and thoracic regions. There was a trend towards increasing levels of NSE. However, the difference in NSE was lost when the patient set was segregated based on AIS group. Conclusions. Our pilot research demonstrates that serum concentrations of cytokines can be used as an affordable and rapid detection tool to accurately stratify SCI severity in patients.

A translational study of somatosensory evoked potential time-frequency components in rats, goats, and humans

Somatosensory evoked potentials (SEPs) have been widely used to assess neurological function in clinical practice. A good understanding of the association between SEP signals and neurological function is helpful for precise diagnosis of impairment location. Previous studies on SEPs have been reported in animal models. However, few studies have reported the relationships between SEP waveforms in animals and those in humans. In this study, we collected normal SEP waveforms and decomposed them into specific time-frequency components (TFCs). Our results showed three stable TFC distribution regions in intact goats and rats and in humans. After we induced spinal cord injury in the animal models, a greater number of small TFC distribution regions were observed in the injured goat and rat groups than in the normal group. Moreover, there were significant correlations (P < 0.05) and linear relationships between the main SEP TFCs of the human group and those of the goat and rat groups. A stable TFC distribution of SEP components was observed in the human, goat and rat groups, and the TFC distribution modes were similar between the three groups. Results in various animal models in this study could be translated to future clinical studies based on SEP TFC analysis. Human studies were approved by the Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster (approval No. UM 05-312 T/975) on December 5, 2005. Rat experiments were approved by the Committee on the Use of Live Animals in Teaching and Research of Li Ka Shing Faculty of Medicine of the University of Hong Kong (approval No. CULART 2912-12) on January 28, 2013. Goat experiments were approved by the Animal Ethics Committee of Affiliated Hospital of Guangdong Medical University (approval No. GDY2002132) on March 5, 2018.

Surgical intervention combined with weight-bearing walking training improves neurological recoveries in 320 patients with clinically complete spinal cord injury: a prospective self-controlled study

Although a large number of trials in the SCI field have been conducted, few proven gains have been realized for patients. In the present study, we determined the efficacy of a novel combination treatment involving surgical intervention and long-term weight-bearing walking training in spinal cord injury (SCI) subjects clinically diagnosed as complete or American Spinal Injury Association Impairment Scale (AIS) Class A (AIS-A). A total of 320 clinically complete SCI subjects (271 male and 49 female), aged 16–60 years, received early (≤ 7 days, n = 201) or delayed (8–30 days, n = 119) surgical interventions to reduce intraspinal or intramedullary pressure. Fifteen days post-surgery, all subjects received a weight-bearing walking training with the “Kunming Locomotion Training Program (KLTP)” for a duration of 6 months. The neurological deficit and recovery were assessed using the AIS scale and a 10-point Kunming Locomotor Scale (KLS). We found that surgical intervention significantly improved AIS scores measured at 15 days post-surgery as compared to the pre-surgery baseline scores. Significant improvement of AIS scores was detected at 3 and 6 months and the KLS further showed significant improvements between all pair-wise comparisons of time points of 15 days, 3 or 6 months indicating continued improvement in walking scores during the 6-month period. In conclusion, combining surgical intervention within 1 month post-injury and weight-bearing locomotor training promoted continued and statistically significant neurological recoveries in subjects with clinically complete SCI, which generally shows little clinical recovery within the first year after injury and most are permanently disabled. This study was approved by the Science and Research Committee of Kunming General Hospital of PLA and Kunming Tongren Hospital, China and registered at ClinicalTrials.gov (Identifier: NCT04034108) on July 26, 2019.

Mechanical properties of spinal cord grey matter and white matter in confined compression

To better understand the link between spinal cord impact and the resulting tissue damage, computational models are often used. These models typically simulate the spinal cord as a homogeneous and isotropic material. Recent research suggests that grey and white matter tissue differences and directional differences, i.e. anisotropy, are important to predict spinal cord damage. The objective of this research was to characterize the mechanical properties of spinal cord grey and white matter tissue in confined compression. Spinal cords (n = 12) were harvested immediately following euthanasia from Yorkshire and Yucatan pigs. The spinal cords were flash frozen (60 s at -80 °C) and prepared into four types of test samples: grey matter axial, grey matter transverse, white matter axial, and white matter transverse. Each sample type was thawed, and subsequently tested in confined compression within 6 h of euthanasia. Samples were compressed to 10% strain at a quasi-static strain rate (0.001/sec) and allowed to relax for 120 s. A quasi-linear viscoelastic model combining a first-order exponential with a 1-term Prony series characterized the loading and relaxation responses respectively. The effect of tissue type (grey matter vs. white matter), direction (axial vs. transverse), and their interaction were evaluated with a two-way ANOVA (p < 0.05) with peak stress, aggregate modulus, and relaxation time as dependent variables. This study found grey matter to be 1.6-2 times stiffer than white matter and both grey and white matter were isotropic in compression. These findings should be emphasized when studying SCI biomechanics using computational models.

A Randomized Controlled Trial of Early versus Late Surgical Decompression for Thoracic and Thoracolumbar Spinal Cord Injury in 73 Patients

Convincing clinical evidence exists to support early surgical decompression in the setting of cervical spinal cord injury (SCI). However, clinical evidence on the effect of early surgery in patients with thoracic and thoracolumbar (from T1 to L1 [T1–L1]) SCI is lacking and a critical knowledge gap remains. This randomized controlled trial (RCT) sought to evaluate the safety and efficacy of early (<24 h) compared with late (24–72 h) decompressive surgery after T1–L1 SCI. From 2010 to 2018, patients (≥16 years of age) with acute T1–L1 SCI presenting to a single trauma center were randomized to receive either early (<24 h) or late (24–72 h) surgical decompression. The primary outcome was an ordinal change in American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade at 12-month follow-up. Secondary outcomes included complications and change in ASIA motor score (AMS) at 12 months. Outcome assessors were blinded to treatment assignment.

Of 73 individuals whose treatment followed the study protocol, 37 received early surgery and 36 underwent late surgery. The mean age was 29.74 ± 11.4 years. In the early group 45.9% of patients and in the late group 33.3% of patients had a ≥1-grade improvement in AIS (odds ratio [OR] 1.70, 95% confidence interval [CI]: 0.66-4.39, p = 0.271); significantly more patients in the early (24.3%) than late (5.6%) surgery group had a ≥2-grade improvement in AIS (OR 5.46, 95% CI: 1.09-27.38, p = 0.025). There was no statistically significant difference in the secondary outcome measures. Surgical decompression within 24 h of acute traumatic T1–L1 SCI is safe and is associated with improved neurological outcome, defined as at least a 2-grade improvement in AIS at 12 months.

Electrical Stimulation as a Tool to Promote Plasticity of the Injured Spinal Cord

Unlike their peripheral nervous system counterparts, the capacity of central nervous system neurons and axons for regeneration after injury is minimal. Although a myriad of therapies (and different combinations thereof) to help promote repair and recovery after spinal cord injury (SCI) have been trialed, few have progressed from bench-top to bedside. One of the few such therapies that has been successfully translated from basic science to clinical applications is electrical stimulation (ES). Although the use and study of ES in peripheral nerve growth dates back nearly a century, only recently has it started to be used in a clinical setting. Since those initial experiments and seminal publications, the application of ES to restore function and promote healing have greatly expanded. In this review, we discuss the progression and use of ES over time as it pertains to promoting axonal outgrowth and functional recovery post-SCI. In doing so, we consider four major uses for the study of ES based on the proposed or documented underlying mechanism: (1) using ES to introduce an electric field at the site of injury to promote axonal outgrowth and plasticity; (2) using spinal cord ES to activate or to increase the excitability of neuronal networks below the injury; (3) using motor cortex ES to promote corticospinal tract axonal outgrowth and plasticity; and (4) leveraging the timing of paired stimuli to produce plasticity. Finally, the use of ES in its current state in the context of human SCI studies is discussed, in addition to ongoing research and current knowledge gaps, to highlight the direction of future studies for this therapeutic modality.

Decision tree analysis to better control treatment effects in spinal cord injury clinical research

OBJECTIVE

The aim of this study was to use decision tree modeling to identify optimal stratification groups considering both the neurological impairment and spinal column injury and to investigate the change in motor score as an example of a practical application. Inherent heterogeneity in spinal cord injury (SCI) introduces variation in natural recovery, compromising the ability to identify true treatment effects in clinical research. Optimized stratification factors to create homogeneous groups of participants would improve accurate identification of true treatment effects.

METHODS

The analysis cohort consisted of patients with acute traumatic SCI registered in the Vancouver Rick Hansen Spinal Cord Injury Registry (RHSCIR) between 2004 and 2014. Severity of neurological injury (American Spinal Injury Association Impairment Scale [AIS grades A-D]), level of injury (cervical, thoracic), and total motor score (TMS) were assessed using the International Standards for Neurological Classification of Spinal Cord Injury examination; morphological injury to the spinal column assessed using the AOSpine classification (AOSC types A-C, C most severe) and age were also included. Decision trees were used to determine the most homogeneous groupings of participants based on TMS at admission and discharge from in-hospital care.

RESULTS

The analysis cohort included 806 participants; 79.3% were male, and the mean age was 46.7 ± 19.9 years. Distribution of severity of neurological injury at admission was AIS grade A in 40.0% of patients, grade B in 11.3%, grade C in 18.9%, and grade D in 29.9%. The level of injury was cervical in 68.7% of patients and thoracolumbar in 31.3%. An AOSC type A injury was found in 33.1% of patients, type B in 25.6%, and type C in 37.8%. Decision tree analysis identified 6 optimal stratification groups for assessing TMS: 1) AOSC type A or B, cervical injury, and age ≤ 32 years; 2) AOSC type A or B, cervical injury, and age > 32-53 years; 3) AOSC type A or B, cervical injury, and age > 53 years; 4) AOSC type A or B and thoracic injury; 5) AOSC type C and cervical injury; and 6) AOSC type C and thoracic injury.

CONCLUSIONS

Appropriate stratification factors are fundamental to accurately identify treatment effects. Inclusion of AOSC type improves stratification, and use of the 6 stratification groups could minimize confounding effects of variable neurological recovery so that effective treatments can be identified.

Role and prospects of regenerative biomaterials in the repair of spinal cord injury

Axonal junction defects and an inhibitory environment after spinal cord injury seriously hinder the regeneration of damaged tissues and neuronal functions. At the site of spinal cord injury, regenerative biomaterials can fill cavities, deliver curative drugs, and provide adsorption sites for transplanted or host cells. Some regenerative biomaterials can also inhibit apoptosis, inflammation and glial scar formation, or further promote neurogenesis, axonal growth and angiogenesis. This review summarized a variety of biomaterial scaffolds made of natural, synthetic, and combined materials applied to spinal cord injury repair. Although these biomaterial scaffolds have shown a certain therapeutic effect in spinal cord injury repair, there are still many problems to be resolved, such as product standards and material safety and effectiveness.

Chondroitinase improves anatomical and functional outcomes after primate spinal cord injury

Inhibitory extracellular matrices form around mature neurons as perineuronal nets containing chondroitin sulfate proteoglycans that limit axonal sprouting after CNS injury. The enzyme chondroitinase (Chase) degrades inhibitory chondroitin sulfate proteoglycans and improves axonal sprouting and functional recovery after spinal cord injury in rodents. We evaluated the effects of Chase in rhesus monkeys that had undergone C7 spinal cord hemisection. Four weeks after hemisection, we administered multiple intraparenchymal Chase injections below the lesion, targeting spinal cord circuits that control hand function. Hand function improved significantly in Chase-treated monkeys relative to vehicle-injected controls. Moreover, Chase significantly increased corticospinal axon growth and the number of synapses formed by corticospinal terminals in gray matter caudal to the lesion. No detrimental effects were detected. This approach appears to merit clinical translation in spinal cord injury.

Heterogeneity among traumatic spinal cord injuries at the thoracolumbar junction: helping select patients for clinical trials

Study design

Retrospective analysis.

Setting

China Rehabilitation Research Center, Beijing, China.

Objective

A retrospective study that documents the modalities and clarifies the heterogeneity among spinal cord injuries (SCIs) caused by trauma to the thoracolumbar vertebral junction.

Methods

X-ray and MRI imaging, neurological records, and the urodynamics results of 190 patients were reviewed and used to categorize different SCI modalities. First, injuries were divided into complete and incomplete injuries using the International Standard for Neurological Classification of Spinal Cord Injury. Next, the complete injuries were further grouped using the neurological level of injury and Long T2 signal from mid-sagittal MRI images, whereas the bulboconvernosus reflexes were also used as a reference to detect injury to the sacral cord.

Results

The SCI modalities were classified into five categories: pure complete epiconus lesion with caudal cord intact (G1), complete epiconus injury with conus medullaris (CM) totally involved in the lesion (G2), CM syndrome, cauda equine syndrome without sacral sparing (G3 and G4), and incomplete injury (G5).

Conclusions

The heterogeneity of SCIs at the thoracolumbar junction was documented, a criterion we propose to be of great significance when selecting patients for clinical trials. In particular, the G2 group, which comprises nearly one third of the patients with epiconus lesions, is sometimes mistaken as G1, an observation that has thus far received insufficient attention.

Innovative mouse model mimicking human-like features of spinal cord injury: efficacy of Docosahexaenoic acid on acute and chronic phases

Traumatic spinal cord injury has dramatic consequences and a huge social impact. We propose a new mouse model of spinal trauma that induces a complete paralysis of hindlimbs, still observable 30 days after injury. The contusion, performed without laminectomy and deriving from the pressure exerted directly on the bone, mimics more closely many features of spinal injury in humans. Spinal cord was injured at thoracic level 10 (T10) in adult anesthetized female CD1 mice, mounted on stereotaxic apparatus and connected to a precision impactor device. Following severe injury, we evaluated motor and sensory functions, and histological/morphological features of spinal tissue at different time points. Moreover, we studied the effects of early and subchronic administration of Docosahexaenoic acid, investigating functional responses, structural changes proximal and distal to the lesion in primary and secondary injury phases, proteome modulation in injured spinal cord. Docosahexaenoic acid was able i) to restore behavioural responses and ii) to induce pro-regenerative effects and neuroprotective action against demyelination, apoptosis and neuroinflammation. Considering the urgent health challenge represented by spinal injury, this new and reliable mouse model together with the positive effects of docosahexaenoic acid provide important translational implications for promising therapeutic approaches for spinal cord injuries.

Acute Spinal Cord Injury: A Systematic Review Investigating miRNA Families Involved

Acute traumatic spinal cord injury (SCI) involves primary and secondary injury mechanisms. The primary mechanism is related to the initial traumatic damage caused by the damaging impact and this damage is irreversible. Secondary mechanisms, which begin as early as a few minutes after the initial trauma, include processes such as spinal cord ischemia, cellular excitotoxicity, ionic dysregulation, and free radical-mediated peroxidation. SCI is featured by different forms of injury, investigating the pathology and degree of clinical diagnosis and treatment strategies, the animal models that have allowed us to better understand this entity and, finally, the role of new diagnostic and prognostic tools such as miRNA could improve our ability to manage this pathological entity. Autopsy could benefit from improvements in miRNA research: the specificity and sensitivity of miRNAs could help physicians in determining the cause of death, besides the time of death.

Development of a traumatic cervical dislocation spinal cord injury model with residual compression in the rat

BACKGROUND

Preclinical spinal cord injury models do not represent the wide range of biomechanical factors seen in human injuries, such as spinal level, injury mechanism, velocity of spinal cord impact, and residual compression. These factors may be responsible for differences observed between experimental and clinical study results, especially related to the controversial issue of timing of surgical decompression.

NEW METHOD

Somatosensory Evoked Potentials were used to: a) characterize residual compression depths in a dislocation model, and b) evaluate the physiological effect of whether or not the spinal cord was decompressed following the initial injury, prior to the application of residual compression. Modifications to vertebral clamps and the development of a novel surgical frame allowed us to conduct surgical and injury procedures in a controlled manner without the risk of additional damage to the spinal cord. Behavioural outcomes were evaluated following varying dislocation displacements, in addition to the survivability of 4 h of residual compression following a traumatic injury.

RESULTS

Residual compression immediately following the initial dislocation demonstrated significantly different electrophysiological response compared to when the residual compression was delayed.

COMPARISON WITH EXISTING METHOD

There are currently no other residual compression models that utilize a dislocation injury mechanism. Many residual compression studies have demonstrated the effectiveness of early decompression, however the compression of the spinal cord is often not representative of clinical traumatic injuries. Preclinical studies typically model residual compression using a sustained force through quasi-static application, when human injuries often occur at high velocities, followed by a sustained displacement occlusion of the spinal canal.

CONCLUSIONS

This study has validated several novel procedural approaches and injury parameters, and provided critical details to implement in the development of a traumatic cervical dislocation SCI model with residual compression.

Material Characterization and Bioanalysis of Hybrid Scaffolds of Carbon Nanomaterial and Polymer Nanofibers

The interconnected porous structures that mimic the extracellular matrix support cell growth in tissue engineering. Nanofibers generated by electrospinning can act as a vehicle for therapeutic cell delivery to a neural lesion. The incorporation of carbon nanomaterials with excellent electrical conductivity in nanofibers is an attractive aspect for design of a nanodevice for neural tissue regeneration. In this study, nanoscaffolds were created by electrospinning poly(ε-caprolactone) (PCL) and three different types of carbon nanomaterials, which are carbon nanotubes, graphene, and fullerene. The component of carbon nanomaterials in nanofibers was confirmed by Fourier transform infrared spectroscopy. The fiber diameter was determined by scanning electron microscopy, and it was found that the diameter varied depending on the type of nanomaterial in the fibers. The incorporation of carbon nanotubes and graphene in the PCL fibers increased the contact angle significantly, while the incorporation of fullerene reduced the contact angle significantly. Incorporation of CNT, fullerene, and graphene in the PCL fibers increased dielectric constant. Astrocytes isolated from neonatal rats were cultured on PCL-nanomaterial nanofibers. The cell viability assay showed that the PCL-nanomaterial nanofibers were not toxic to the cultured astrocytes. The immunolabeling showed the growth and morphology of astrocytes on nanofiber scaffolds. SEM was performed to determine the cell attachment and interaction with the nanoscaffolds. This study indicates that PCL nanofibers containing nanomaterials are biocompatible and could be used for cell and drug delivery into the nervous system.

Development of a Multimodal Apparatus to Generate Biomechanically Reproducible Spinal Cord Injuries in Large Animals

Rodents are widespread animal models in spinal cord injury (SCI) research. They have contributed to obtaining important information. However, some treatments only tested in rodents did not prove efficient in clinical trials. This is probably a result of significant differences in the physiology, anatomy, and complexity between humans and rodents. To bridge this gap in a better way, a few research groups use pig models for SCI. Here we report the development of an apparatus to perform biomechanically reproducible SCI in large animals, including pigs. We present the iterative process of engineering, starting with a weight-drop system to ultimately produce a spring-load impactor. This device allows a graded combination of a contusion and a compression injury. We further engineered a device to entrap the spinal cord and prevent it from escaping at the moment of the impact. In addition, it provides identical resistance around the cord, thereby, optimizing the inter-animal reproducibility. We also present other tools to straighten the vertebral column and to ease the surgery. Sensors mounted on the impactor provide information to assess the inter-animal reproducibility of the impacts. Further evaluation of the injury strength using neurophysiological recordings, MRI scans, and histology shows consistency between impacts. We conclude that this apparatus provides biomechanically reproducible spinal cord injuries in pigs.

Reduction of Inflammation and Enhancement of Motility after Pancreatic Islet Derived Stem Cell Transplantation Following Spinal Cord Injury

Objective

Spinal cord injury (SCI) is a very serious health problem, usually caused by a trauma and accompanied by elevated levels of inflammation indicators. Stem cell-based therapy is promising some valuable strategies for its functional recovery. Nestin-positive progenitor and/or stem cells (SC) isolated from pancreatic islets (PI) show mesenchymal stem cell (MSC) characteristics. For this reason, we aimed to analyze the effects of rat pancreatic islet derived stem cell (rPI-SC) delivery on functional recovery, as well as the levels of inflammation factors following SCI.

Methods

rPI-SCs were isolated, cultured and their MSC characteristics were determined through flow cytometry and immunofluorescence analysis. The experimental rat population was divided into three groups : 1) laminectomy & trauma, 2) laminectomy & trauma & phosphate-buffered saline (PBS), and 3) laminectomy+trauma+SCs. Green fluorescent protein (GFP) labelled rPI-SCs were transplanted into the injured rat spinal cord. Their motilities were evaluated with Basso, Beattie and Bresnahan (BBB) Score. After 4-weeks, spinal cord sections were analyzed for GFP labeled SCs and stained for vimentin, S100β, brain derived neurotrophic factor (BDNF), 2’,3’-cyclic-nucleotide 3'-phosphodiesterase (CNPase), vascular endothelial growth factor (VEGF) and proinflammatory (interleukin [IL]-6, transforming growth factor [TGF]-β, macrophage inflammatory protein [MIP]-2, myeloperoxidase [MPO]) and anti-inflammatory (IL-1 receptor antagonis) factors.

Results

rPI-SCs were revealed to display MSC characteristics and express neural and glial cell markers including BDNF, glial fibrillary acidic protein (GFAP), fibronectin, microtubule associated protein-2a,b (MAP2a,b), β3-tubulin and nestin as well as antiinflammatory prostaglandin E2 receptor, EP3. The BBB scores showed significant motor recovery in group 3. GFP-labelled cells were localized on the injury site. In addition, decreased proinflammatory factor levels and increased intensity of anti-inflammatory factors were determined.

Conclusion

Transplantation of PI-SCs might be an effective strategy to improve functional recovery following spinal cord trauma.

An anti-inflammatory peptide and brain-derived neurotrophic factor-modified hyaluronan-methylcellulose hydrogel promotes nerve regeneration in rats with spinal cord injury

Background

Traumatic spinal cord injury (SCI) causes neuronal death, demyelination, axonal degeneration, inflammation, glial scar formation, and cystic cavitation resulting in interruption of neural signaling and loss of nerve function. Multifactorial targeted therapy is a promising strategy for SCI.

Methods

The anti-inflammatory peptide KAFAKLAARLYRKALARQLGVAA (KAFAK) and brain-derived neurotrophic factor (BDNF)-modified hyaluronan-methylcellulose (HAMC) hydrogel was designed for minimally invasive, localized, and sustained intrathecal protein delivery. The physical and biological characteristics of HAMC-KAFAK/BDNF hydrogel were measured in vitro. SCI model was performed in rats and HAMC-KAFAK/BDNF hydrogel was injected into the injured site of spinal cord. The neuronal regeneration effect was evaluated by inflammatory cytokine levels, behavioral test and histological analysis at 8 weeks post operation.

Results

HAMC-KAFAK/BDNF hydrogel showed minimally swelling property and sustained release of the KAFAK and BDNF. HAMC-KAFAK/BDNF hydrogel significantly improved the proliferation of PC12 cells in vitro without cytotoxicity. Significant recovery in both neurological function and nerve tissue morphology in SCI rats were observed in HAMC-KAFAK/BDNF group. HAMC-KAFAK/BDNF group showed significant reduction in proinflammatory cytokines expression and cystic cavitation, decreased glial scar formation, and improved neuronal survival in the rat SCI model compared to HAMC group and SCI group.

Conclusion

The HAMC-KAFAK/BDNF hydrogel promotes functional recovery of rats with spinal cord injury by regulating inflammatory cytokine levels and improving axonal regeneration.

Anatomic conditions for bypass surgery between rostral (T7-T9) and caudal (L2, L4, S1) ventral roots to treat paralysis after spinal cord injury

Severe spinal cord injuries cause permanent neurological deficits and are still considered as inaccessible to efficient therapy. Injured spinal cord axons are unable to spontaneously regenerate. Re-establishing functional activity especially in the lower limbs by reinnervation of the caudal infra-lesional territories might represent an effective therapeutic strategy. Numerous surgical neurotizations have been developed to bridge the spinal cord lesion site and connect the intact supra-lesional portions of the spinal cord to peripheral nerves (spinal nerves, intercostal nerves) and muscles. The major disadvantage of these techniques is the increased hypersensitivity, spasticity and pathologic pain in the spinal cord injured patients, which occur due to the vigorous sprouting of injured afferent sensory fibers after reconstructive surgery. Using micro-surgical instruments and an operation microscope we performed detailed anatomical preparation of the vertebral canal and its content in five human cadavers. Our observations allow us to put forward the possibility to develop a more precise surgical approach, the so called "ventral root bypass" that avoids lesion of the dorsal roots and eliminates sensitivity complications. The proposed kind of neurotization has been neither used, nor put forward. The general opinion is that radix ventralis and radix dorsalis unite to form the spinal nerve inside the dural sac. This assumption is not accurate, because both radices leave the dural sac separately. This neglected anatomical feature allows a reliable intravertebral exposure of the dura-mater ensheathed ventral roots and their damage-preventing end-to-side neurorrhaphy by interpositional nerve grafts.

Differences in neuroplasticity after spinal cord injury in varying animal models and humans

Rats have been the primary model to study the process and underlying mechanisms of recovery after spinal cord injury. Two weeks after a severe spinal cord contusion, rats can regain weight-bearing abilities without therapeutic interventions, as assessed by the Basso, Beattie and Bresnahan locomotor scale. However, many human patients suffer from permanent loss of motor function following spinal cord injury. While rats are the most understood animal model, major differences in sensorimotor pathways between quadrupeds and bipeds need to be considered. Understanding the major differences between the sensorimotor pathways of rats, non-human primates, and humans is a start to improving targets for treatments of human spinal cord injury. This review will discuss the neuroplasticity of the brain and spinal cord after spinal cord injury in rats, non-human primates, and humans. A brief overview of emerging interventions to induce plasticity in humans with spinal cord injury will also be discussed.

Hypothermic treatment after computer-controlled compression in minipig: A preliminary report on the effect of epidural vs. direct spinal cord cooling

The aim of the present study was to investigate the therapeutic efficacy of local hypothermia (beginning 30 min post-injury persisting for 5 h) on tissue preservation along the rostro-caudal axis of the spinal cord (3 cm cranially and caudally from the lesion site), and the prevention of injury-induced functional loss in a newly developed computer-controlled compression model in minipig (force of impact 18N at L3 level), which mimics severe spinal cord injury (SCI). Minipigs underwent SCI with two post-injury modifications (durotomy vs. intact dura mater) followed by hypothermia through a perfusion chamber with cold (epidural t≈15°C) saline, DMEM/F12 or enriched DMEM/F12 (SCI/durotomy group) and with room temperature (t≈24°C) saline (SCI-only group). Minipigs treated with post-SCI durotomy demonstrated slower development of spontaneous neurological improvement at the early postinjury time points, although the outcome at 9 weeks of survival did not differ significantly between the two SCI groups. Hypothermia with saline (t≈15°C) applied after SCI-durotomy improved white matter integrity in the dorsal and lateral columns in almost all rostro-caudal segments, whereas treatment with medium/enriched medium affected white matter integrity only in the rostral segments. Furthermore, regeneration of neurofilaments in the spinal cord after SCI-durotomy and hypothermic treatments indicated an important role of local saline hypothermia in the functional outcome. Although saline hypothermia (24°C) in the SCI-only group exhibited a profound histological outcome (regarding the gray and white matter integrity and the number of motoneurons) and neurofilament protection in general, none of the tested treatments resulted in significant improvement of neurological status. The findings suggest that clinically-proven medical treatments for SCI combined with early 5 h-long saline hypothermia treatment without opening the dural sac could be more beneficial for tissue preservation and neurological outcome compared with hypothermia applied after durotomy.

Ultra-Early (<12 Hours) Surgery Correlates With Higher Rate of American Spinal Injury Association Impairment Scale Conversion After Cervical Spinal Cord Injury

BACKGROUND

Cervical spinal cord injury (SCI) is a devastating condition with very few treatment options. It remains unclear if early surgery correlated with conversion of American Spinal Injury Association Impairment Scale (AIS) grade A injuries to higher grades.

OBJECTIVE

To determine the optimal time to surgery after cervical SCI through retrospective analysis.

METHODS

We collected data from 48 patients with cervical SCI. Based on the time from Emergency Department (ED) presentation to surgical decompression, we grouped patients into ultra-early (decompression within 12 h of presentation), early (within 12-24 h), and late groups (&gt;24 h). We compared the improvement in AIS grade from admission to discharge, controlling for confounding factors such as AIS grade on admission, injury severity, and age. The mean time from injury to ED for this group of patients was 17 min.

RESULTS

Patients who received surgery within 12 h after presentation had a relative improvement in AIS grade from admission to discharge: the ultra-early group improved on average 1.3. AIS grades compared to 0.5 in the early group (P = .02). In addition, 88.8% of patients with an AIS grade A converted to a higher grade (AIS B or better) in the ultra-early group, compared to 38.4% in the early and late groups (P = .054).

CONCLUSION

These data suggest that surgical decompression after SCI that takes place within 12 h may lead to a relative improved neurological recovery compared to surgery that takes place after 12 h.

The Importance of Early Surgical Decompression for Acute Traumatic Spinal Cord Injury

Background

Traumatic spinal cord injury (SCI) is a tragic event that has a major impact on individuals and society as well as the healthcare system. The purpose of this study was to investigate the strength of association between surgical treatment timing and neurological improvement.

Methods

Fifty-six patients with neurological impairment due to traumatic SCI were included in this study. From January 2013 to June 2017, all their medical records were reviewed. Initially, to identify the factors affecting the recovery of neurological deficit after an acute SCI, we performed univariate logistic regression analyses for various variables. Then, we performed a multivariate logistic regression analysis for variables that showed a p-value of < 0.2 in the univariate analyses. The Hosmer-Lemeshow test was used to determine the goodness of fit for the multivariate logistic regression model.

Results

In the univariate analysis on the strength of associations between various factors and neurological improvement, the following factors had a p-value of < 0.2: surgical timing (early, < 8 hours; late, 8–24 hours; p = 0.033), completeness of SCI (complete/incomplete; p = 0.033), and smoking (p = 0.095). In the multivariate analysis, only two variables were significant: surgical timing (odds ratio [OR], 0.128; p = 0.004) and completeness of SCI (OR, 9.611; p = 0.009).

Conclusions

Early surgical decompression within 8 hours after traumatic SCI appeared to improve neurological recovery. Furthermore, incomplete SCI was more closely related to favorable neurological improvement than complete SCI. Therefore, we recommend early decompression as an effective treatment for traumatic SCI.

Diffusion tensor imaging shows mechanism-specific differences in injury pattern and progression in rat models of acute spinal cord injury

We investigate the ability of diffusion tensor imaging (DTI) to distinguish between three experimental rat models of spinal cord injury mechanism - contusion, dislocation, and distraction. Ex vivo DTI scans were performed on cord specimens that were preserved at different time points of the acute injury (3 hr, 24 hr, and 7 days post-injury) across all three injury mechanisms. White matter was classified as abnormal if their DTI metric was substantially different from regional values measured from a set of uninjured controls, thus allowing generation of binary "white matter damage maps" which categorizes each pixel in the DTI image as "normal" or "damaged". Damage classification was most robust using thresholds in the longitudinal diffusivity, which supports previous studies that show that longitudinal diffusivity is the most robust DTI metric in depicting damage in SCI. Furthermore, the spatial damage patterns from all subjects in the same group were consolidated into a "damage occurrence ratio map", which illustrates an average damage shape that characterizes the injury mechanism. Our analysis has yielded a dataset which highlights the differences in injury pattern due to the initial mode of mechanical injury. For example, contusion produced an initial injury that emanated radially outward from the central canal, with subsequent damage along the caudal corticospinal tract and rostral gracile fasciculus; dislocation injuries showed a high level of involvement in the lateral and ventral white matter which became less apparent by 7 days post-injury, and distraction injuries were found to be less focal and more distributed rostrocaudally. This work represents a first step in adopting the use of the primary injury mechanism as a clinical prognostic factor in SCI, which may help to inform the trialing of existing neuroprotective treatment candidates, the development of new therapies as well as personalize the management of SCI for the individual patient.