Current status of clinical trials for acute spinal cord injury

Does dexmedetomidine reduce secondary damage after spinal cord injury? An experimental study

The aim of this experimental study was to investigate the possible protective effect of dexmedetomidine (DEX) on traumatic spinal cord injury (SCI). Twenty-two New Zealand rabbits were divided into three groups: sham (no drug or operation, n = 6), Control [SCI + single dose of 1 mL saline intraperitoneally (i.p), after trauma; n = 8] and DEX (SCI + 1 microg/kg dexmedetomidine in 1 mL, i.p, after trauma, n = 8). Laminectomy was performed at T10 and balloon angioplasty catheter was applied extradurally. Four and 24 h after surgery, rabbits were evaluated by an independent observer according to the Tarlov scoring system. Blood, cerebrospinal fluid (CSF), tissue samples from spinal cord were taken for biochemical and histopathological evaluations. After 4 h of SCI, all animals in control or DEX treated groups became paraparesic. On the other hand, 24 h after SCI, partial improvements were observed in both control and DEX treated groups. Traumatic SCI leads to increase in the lipid peroxidation and decreases enzymatic or nonenzymatic endogenous antioxidative defense systems. Again, SCI leads to apoptosis in spinal cord. DEX treatment slightly prevented lipid peroxidation and augmented endogenous antioxidative defense systems in CSF or spinal cord tissue, but failed to prevent apoptosis or neurodeficit after traumatic SCI. Therefore, it could be suggested that treatment with dexmedetomidine does not produce beneficial results in SCI.

Window of opportunity: flexion myelopathy after drug overdose

BACKGROUND

Cervical and thoracic flexion myelopathy are uncommon causes of spinal cord injury that can lead to irreversible paralysis, autonomic dysfunction, and death. To the authors' knowledge, this report is the first to describe the natural history of flexion myelopathy and the simultaneous occurrence of cervical and thoracic flexion myelopathy in the setting of drug overdose.

OBJECTIVES

To report the association of cervical and thoracic flexion myelopathy and drug overdose; to describe the subacute natural history of flexion myelopathy in the setting of drug overdose; to emphasize the need for first responders to document positioning of unresponsive individuals; and to suggest careful neurological examination and early spinal cord imaging in appropriately identified patients at risk of flexion myelopathy.

CASE REPORT

We describe the case of a 34-year-old woman who developed flexion myelopathy resulting in severe quadriparesis after overdose of quetiapine fumarate, oxycodone/acetaminophen, and chloral hydrate.

CONCLUSION

Flexion myelopathy in the setting of drug overdose is a subacute injury. Early intervention may limit neurological disability. However, the clinical diagnosis of flexion myelopathy is inevitably delayed by the patient's altered level of consciousness or mental status at presentation, and concurrent multiple organ failure.

Endogenous neural progenitor cells as therapeutic target after spinal cord injury

Growing knowledge about the role of neural progenitor cells supports the hope that stem cell-based therapeutic approaches aimed at restoring function in the lesioned central nervous system can be established. Possible therapies for promoting recovery after spinal cord injury include stimulating the formation of neurons and glial cells by endogenous progenitor cells. This article reviews the current knowledge about the nature of adult progenitor cells in the intact and injured spinal cord and summarizes possibilities and limitations of cellular replacement strategies based on manipulations of endogenous spinal cord progenitor cells and their environment.

Early complications of high-dose methylprednisolone in acute spinal cord injury patients

BACKGROUND

To evaluate the early complications and effect on neurological outcome of methylprednisolone (MP) treatment in spinal cord injury (SCI) patients during the acute phase.

METHODS

We retrospectively reviewed the whole cohort of patients admitted to our ICU between January 1994 and December 2005 due to acute SCI. Patients were grouped according to the medical treatment received (MP group versus no-MP group). Patient data as age, gender, Glasgow coma score (GCS), APACHE II, injury severity score (ISS) and ICU stay were recorded. Outcome at ICU discharge and neurological function based on Frankel grade was recorded at ICU admission and at ICU discharge. Early complications were also noted.

RESULTS

There were no differences between both groups in ICU mortality (OR=0.48; 95% CI: 0.08-3.64) nor neurological function at ICU discharge. (OR=1.09; 95% CI: 0.35-3.66). MP group presented an increase in respiratory tract infections (OR=8.19; 95% CI: 1.10-358.6) and in total infections (OR=4.90; 95% CI: 1.46-18.83) compared to no-MP group during the ICU stay. There was a significant increase in the incidence of hyperglycaemia in the MP group (OR=17.0; 95% CI: 4.52-66.3).

CONCLUSIONS

The use of MP in patients with acute SCI is not associated with an improvement in outcome or neurological function at ICU discharge. Moreover, the use of MP is associated with an increased risk of infectious and metabolic complications during ICU stay.

Blocking connexin43 expression reduces inflammation and improves functional recovery after spinal cord injury

After traumatic CNS injury, a cascade of secondary events expands the initial lesion. The gap-junction protein connexin43 (Cx43), which is transiently up-regulated, has been implicated in the spread of 'bystander' damage. We have used an antisense oligodeoxynucleotide (asODN) to suppress Cx43 up-regulation in two rat models of spinal cord injury. Within 24 h of compression injury, rats treated with Cx43-asODN scored higher than sense-ODN and vehicle-treated controls on behavioural tests of locomotion. Their spinal cords showed less swelling and tissue disruption, less up-regulation of astrocytic GFAP, and less extravasation of fluorescently-labelled bovine serum albumin and neutrophils. The locomotor improvement was sustained over at least 4 weeks. Following partial spinal cord transection, Cx43-asODN treatment reduced GFAP immunoreactivity, neutrophil recruitment, and the activity of OX42(+) microglia in and around the lesion site. Cx43 has many potential roles in the pathophysiology of CNS injury and may be a valuable target for therapeutic intervention.

Pregabalin as a neuroprotector after spinal cord injury in rats

The over-expression of excitotoxic neurotransmitter, such as glutamate, is an important mechanism of secondary injury after spinal cord injury. The authors examined the neuroprotective effect of pregabalin (GP) which is known as to reduce glutamate secretion, in a rat model of spinal cord injury. Thirty-two male Sprague-Dawley rats were randomly allocated to four groups; the control group (contusion injury only), the methylprednisolone treated group, the minocycline treated group and the GP treated group. Spinal cord injury was produced by contusion using the New York University impactor (25 g-cm, at the 9th-10th thoracic). Functional evaluations were done using the inclined plane test and a motor rating scale. Anti-apoptotic and anti-inflammatory effects were evaluated by in situ nick-end labeling staining technique (TUNEL) and immunofluorescence staining of cord tissues obtained at 7 days post-injury. Pregabalin treated animals showed significantly better functional recovery, and anti-apoptotic and anti-inflammatory effects. Mean numbers of TUNEL positive cells in the respective groups were 63.5 +/- 7.4, 53.6 +/- 4.0, 44.2 +/- 3.9 and 36.5 +/- 3.6. Double staining (TUNEL and anti-CC1) for oligodendrocyte apoptosis, was used to calculate oligodendrocyte apoptotic indexes (AI), using the following formula AI = (No. of doubly stained cells/No. of anti-CC1 positive cells) x 100. Mean group AIs were 88.6, 46.7, 82.1 and 70.3%, respectively. Mean numbers of activated microglia (anti-OX-42 positive cells) in high power fields were 29.8 +/- 3.9, 22.7 +/- 4.1, 21.0 +/- 3.9 and 17.8 +/- 4.3, respectively. This experiment demonstrates that GP can act as a neuroprotector after SCI in rats, and its anti-apoptotic and anti-inflammatory effects are related to its neuroprotective effect. Further studies are needed to unveil the specific mechanism involved at the receptor level.

Acute spinal cord injury

Acute spinal cord injury is a devastating disease with enormous repercussions, not only for the victims and their families but for society as a whole. Despite the advent of novel medical therapies for the treatment of these injuries, many patients with spinal cord injury remain severely incapacitated and dependent on their families and/or specialized nursing care. Much of the controversy in the treatment of these injuries stems from insufficient knowledge about the pathophysiology of the disease as well as the timing of certain treatments such as surgery. We discuss the diagnosis and management of these injuries as well as novel therapies on the horizon. The recent emphasis on evidence-based medicine has resulted in the creation of guidelines from the American Association of Neurological Surgeons and the Congress of Neurological Surgeons, which will hopefully result in some standardization of care. It is our opinion that early recognition of spinal cord injury and careful management in an intensive care setting can prevent many of the medical complications that are the major source of morbidity and mortality in these patients.

Spinal cord injury: time to move?

This symposium aims at summarizing some of the scientific bases for current or planned clinical trials in patients with spinal cord injury (SCI). It stems from the interactions of four researchers involved in basic and clinical research who presented their work at a dedicated Symposium of the Society for Neuroscience in San Diego. After SCI, primary and secondary damage occurs and several endogenous processes are triggered that may foster or hinder axonal reconnection from supralesional structures. Studies in animals show that some of these processes can be enhanced or decreased by exogenous interventions using drugs to diminish repulsive barriers (anti-Nogo, anti-Rho) that prevent regeneration and/or sprouting of axons. Cell grafts are also envisaged to enhance beneficial immunological mechanisms (autologous macrophages, vaccines) or remyelinate axons (oligodendrocytes derived from stem cells). Some of these treatments could be planned concurrently with neurosurgical approaches that are themselves beneficial to decrease secondary damage (e.g., decompression/reconstructive spinal surgery). Finally, rehabilitative approaches based on the presence of functional networks (i.e., central pattern generator) below the lesion combined with the above neurobiological approaches may produce significant functional recovery of some sensorimotor functions, such as locomotion, by ensuring an optimal function of endogenous spinal networks and establishing new dynamic interactions with supralesional structures. More work is needed on all fronts, but already the results offer great hope for functional recovery after SCI based on sound basic and clinical neuroscience research.

Minocycline, a possible neuroprotective agent in Leber’s hereditary optic neuropathy (LHON): Studies of cybrid cells bearing 11778 mutation

Leber's hereditary optic neuropathy (LHON) is a retinal neurodegenerative disorder caused by mitochondrial DNA point mutations. Complex I of the respiratory chain affected by the mutation results in a decrease in ATP and an increase of reactive oxygen species production. Evaluating the efficacy of minocycline in LHON, the drug increased the survival of cybrid cells in contrast to the parental cells after thapsigargin-induced calcium overload. Similar protection was observed by treatment with cyclosporine A, a blocker of the mitochondrial permeability transition pore (mPTP). Ratiometric Ca(2+) imaging reveals that acetylcholine/thapsigargin triggered elevation of the cytosolic calcium concentration is alleviated by minocycline and cyclosporine A. The mitochondrial membrane potential of LHON cybrids was significantly conserved and the active-caspase-3/procaspase-3 ratio was decreased in both treatments. Our observations show that minocycline inhibits permeability transition induced by thapsigargin in addition to its antioxidant effects. In relation with its high safety profile, these results would suggest minocycline as a promising neuroprotective agent in LHON.

Withanoside IV improves hindlimb function by facilitating axonal growth and increase in peripheral nervous system myelin level after spinal cord injury

Although methylprednisolone is the clinically standard medication and almost the only therapy for spinal cord injury (SCI), its effect on functional recovery remains questionable. Transplantation strategies using sources such as neural stem cells and embryonic spinal cord still have some hurdles to overcome before practical applications become available. We therefore aimed to develop a practical medication for SCI. Per oral treatment with withanoside IV, which was previously shown to regenerate neuronal networks in the brain, improved locomotor functions in mice with SCI. In the spinal cord after SCI, axons were crushed in the white matter and gray matter, and central nervous system (CNS) myelin level decreased. In mice treated with withanoside IV (10micromol/kg body weight/day, for 21 days), axonal density and peripheral nervous system (PNS) myelin level increased. The loss of CNS myelin and increase in reactive gliosis were not affected by withanoside IV. These results suggest that oral administration of withanoside IV may ameliorate locomotor functions by facilitating both axonal regrowth and increase in PNS myelin level.

Schwann cell and olfactory ensheathing cell implantation for repair of the contused spinal cord

A contusion injury to the spinal cord results in impaired neurological functions due to neuronal death, and axonal damage and demyelination. In time, a fluid-filled cyst forms at the site of the initial impact. There are no effective endogenous repair mechanisms and, consequently, injury-induced functional deficits are permanent. One aspect of spinal cord repair is that severed descending and ascending axons need to regenerate beyond the site of injury towards the denervated spinal regions where they can become part of axonal circuits involved in motor and sensory function. Implantation of cells into the injured cord has been studied extensively as a means to promote axonal regeneration in the injured spinal cord. Depending on the overall damage, different cell types may be appropriate in different types of injury. To accomplish axonal regeneration in the contused spinal cord, the strengths and limitations of two glial cell types in particular will be discussed; Schwann cells and olfactory ensheathing cells. It is known that with these implants, axonal regeneration is frustrated by the presence of a glial scar surrounding the contused area. I will review current approaches aimed at overcoming this axonal growth inhibitory scar. Future studies need to focus on identifying interventions that, in combination with cellular implants, will elicit substantial axonal growth beyond the contusion injury, which may then be the basis for biologically significant functional recovery.

Timing of thoracic and lumbar fracture fixation in spinal injuries: a systematic review of neurological and clinical outcome

A systematic review of all available evidence on the timing of surgical fixation for thoracic and lumbar fractures with respect to clinical and neurological outcome was designed. The purpose of this review is to clarify some of the controversy about the timing of surgical fracture fixation in spinal trauma. Better neurological outcome, shorter hospital stay and fewer complications have been reported after early fracture fixation. But there are also studies showing no difference in neurological outcome when compared to late treatment. Mortality is another controversial point since a recent report of higher mortality in early treated patients. A systematic review of the literature was preformed. Ten articles were included. Early fracture fixation is associated with less complications, shorter hospital and ICU stay. The effect of early treatment on the neurological outcome remains unclear due to the contradictory results of the included studies. Early thoracic and lumbar fracture fixation results in improvement of clinical outcome, but the effect on neurological outcome remains controversial.

Management of spinal injury

Spinal injury often affects young adults and results in debilitating neurological status, which in turn places a significant burden on society. This review article describes the current practice and controversies surrounding the management of spinal injury. General principles of pre-hospital management, resuscitation, medical treatment, surgical intervention and future advancement are reviewed.

Therapeutic interventions after spinal cord injury

Spinal cord injury (SCI) can lead to paraplegia or quadriplegia. Although there are no fully restorative treatments for SCI, various rehabilitative, cellular and molecular therapies have been tested in animal models. Many of these have reached, or are approaching, clinical trials. Here, we review these potential therapies, with an emphasis on the need for reproducible evidence of safety and efficacy. Individual therapies are unlikely to provide a panacea. Rather, we predict that combinations of strategies will lead to improvements in outcome after SCI. Basic scientific research should provide a rational basis for tailoring specific combinations of clinical therapies to different types of SCI.

The timing of surgical intervention in the treatment of spinal cord injury: a systematic review of recent clinical evidence

STUDY DESIGN

Evidence-based literature review.

OBJECTIVE

To provide updated evidence-based recommendations regarding spinal cord decompression in patients with acute spinal cord injury (SCI).

SUMMARY OF BACKGROUND DATA

It is controversial whether early decompression following SCI conveys a benefit in neurologic outcome.

METHODS

MEDLINE search of experimental and clinical studies showing the effect of decompression on neurologic outcome following SCI. We focused on articles published within the last 10 years, with a particular emphasis on research conducted within the past 5 years.

RESULTS

A total of 66 articles were retrieved. Animal studies consistently show that neurologic recovery is enhanced by early decompression. There was 1 randomized controlled trial that showed no benefit to early (<72 hours) decompression. Several recent prospective series suggest that early decompression (<72 hours) can be performed safely and may improve neurologic outcomes. A recent systematic review showed that early decompression (<24 hours) resulted in statistically better outcomes compared to both delayed decompression and conservative treatment.

CONCLUSIONS

There are currently no standards regarding the role and timing of decompression in acute SCI. We recommend urgent decompression of bilateral locked facets in a patient with incomplete tetraplegia or in a patient with SCI with neurologic deterioration. Urgent decompression in acute cervical SCI remains a reasonable practice option and can be performed safely. There is emerging evidence that surgery within 24 hours may reduce length of intensive care unit stay and reduce post-injury medical complications.

Activated microglia contribute to the maintenance of chronic pain after spinal cord injury

Traumatic spinal cord injury (SCI) results not only in motor impairment but also in chronic central pain, which can be refractory to conventional treatment approaches. It has been shown recently that in models of peripheral nerve injury, spinal cord microglia can become activated and contribute to development of pain. Considering their role in pain after peripheral injury, and because microglia are known to become activated after SCI, we tested the hypothesis that activated microglia contribute to chronic pain after SCI. In this study, adult male Sprague Dawley rats underwent T9 spinal cord contusion injury. Four weeks after injury, when lumbar dorsal horn multireceptive neurons became hyperresponsive and when behavioral nociceptive thresholds were decreased to both mechanical and thermal stimuli, intrathecal infusions of the microglial inhibitor minocycline were initiated. Electrophysiological experiments showed that minocycline rapidly attenuated hyperresponsiveness of lumbar dorsal horn neurons. Behavioral data showed that minocycline restored nociceptive thresholds, at which time spinal microglial cells assumed a quiescent morphological phenotype. Levels of phosphorylated-p38 were decreased in SCI animals receiving minocycline. Cessation of delivery of minocycline resulted in an immediate return of pain-related phenomena. These results suggest an important role for activated microglia in the maintenance of chronic central below-level pain after SCI and support the newly emerging role of non-neuronal immune cells as a contributing factor in post-SCI pain.

Part 1: recognizing neonatal spinal cord injury

Neonatal spinal cord injury can occur in utero, as well as after either a difficult delivery or a nontraumatic delivery. Spinal cord injury can also be related to invasive nursery procedures or underlying neonatal pathology. Early clinical signs of spinal cord injury that has occurred in utero or at delivery includes severe respiratory compromise and profound hypotonia. Knowledge of risk factors and awareness of symptoms is required for early recognition and appropriate treatment. This article reviews the embryological development of the spinal column highlighting mechanisms of injury and identifying underlying factors that increase the risk of spinal cord injury in newborns. Signs and symptoms of injury, cervical spine immobilization, and the differential diagnosis are discussed. Nursing implications, general prognosis, and research in spinal cord injury are provided.