Spinal Cord Injury Update
Fall 2009: Volume 18, Number 3
Literature Review
The articles previewed below were selected by the editors because they include potentially useful information on the diagnosis or management of spinal cord injury and its complications. How to obtain complete articles.
Contents
-
Repair and restorative therapies
-
Hypothermia for acute care
-
Spasticity
-
Assistive technology
-
Walking
-
Pressure ulcer prevention
-
Bowel management
-
Neurological change
Repair and restorative therapies
Stem cell-based therapies for spinal cord injury.
This paper reviews stem cell applications for spinal cord repair. It provides a definition of different stem cell types and describes the mechanisms that could be used to limit damage or repair the spinal cord, including neuroprotective strategies and axon regeneration. The paper reviews the ethical issues surrounding the use of embryonic stem cells (ESCs), and summarizes the advantages and disadvantages of using adult stem cells as an alternative to ESCs. While stem cell therapies have shown promise in animal studies of spinal cord injury, the risks to humans are unclear and several hurdles still need to be overcome. Ethical concerns surrounding the use and possible misuse of both embryonic and adult stem cells also need to be resolved.
Tewarie RS, Hurtado A, Bartels RH, et al.
J Spinal Cord Med. 2009;32(2):105-14.
Systemic administration of an antagonist of the ATP-sensitive receptor P2X7 improves recovery after spinal cord injury.
Traumatic spinal cord injury is characterized by an immediate, irreversible loss of tissue at the lesion site, followed by secondary expansion of tissue damage over time. No effective treatment options currently exist to prevent secondary injury. Excessive release of the chemical ATP at the time of injury plays a role in secondary injury. The authors found that administering Brilliant blue G (BBG) a P2X7R antagonist, 15 minutes after injury in rats, reduced spinal cord anatomic damage and improved motor recovery without evident toxicity. Moreover, BBG treatment directly reduced local activation of astrocytes and microglia, as well as neutrophil infiltration. BBG is a derivative of a commonly used blue food color (FD&C blue No. 1), which crosses the blood–brain barrier. The authors suggest that this may be a feasible approach to treating traumatic SCI in humans.
Peng W, Cotrina M, Han X, et al.
PNAS July 28, 2009 vol. 106 no. 30 12489-12493
Activity-based restorative therapies: Concepts and applications in spinal cord injury-related neurorehabilitation.
This article reviews basic and clinical science evidence pertaining to using physical activity and exercise as a therapeutic tool in the management of chronic spinal cord-related neurological paralysis. The concept of an irreparable central nervous system (CNS) is slowly being replaced with evidence related to CNS plasticity, repair and regeneration, all related to persistently maintaining appropriate levels of neurological activity both below and above the area where the damage occurred. Activity-based restorative therapies (ABRTs) are a new fundamental approach to deficits induced by neurological paralysis. The goal of this approach is to achieve activation of the neurological levels located both above and below the injury level using rehabilitation therapies. While ABRTs are not the “cure” for paralysis, they are evidence-based therapeutic interventions that can be used as a tool for neurological recovery.
Sadowsky CL, Mcdonald JW
Developmental Disabilities Research Reviews 15: 112 – 116 (2009)
Toward the restoration of hand use to a paralyzed monkey: brain-controlled functional electrical stimulation of forearm muscles.
Functional electrical stimulation (FES) of forearm and hand muscles has been used to provide basic, voluntary hand grasp to hundreds of individuals with SCI. However, even the most advanced systems limit hand function to the few tasks programmed into the controller. In contrast, the authors are developing a system that uses neural signals recorded from a multi-electrode array implanted in the motor cortex of the brain. This system has the potential to provide independent control of multiple muscles over a broad range of functional tasks. Two monkeys were able to use this cortically controlled FES system to control the contraction of four forearm muscles despite temporary limb paralysis. Furthermore, the monkeys were able to control the magnitude and time course of the force with sufficient accuracy to match a cursor to targets at different force levels. The authors are working to refine this approach to allow voluntary control of more complex and varied hand movements. These results suggest that brain-controlled FES prostheses may ultimately benefit paralyzed patients with injuries in the mid-cervical spinal cord and be of even greater benefit to individuals with high-cervical injuries and paralysis of the entire upper limb.
Pohlmeyer EA, Oby ER, Perreault EJ, et al.
PLoS One. 2009 Jun 15;4(6):e5924.
[Return to top]
Hypothermia for acute care
Therapeutic hypothermia for spinal cord injury.
This review summarizes experimental and clinical studies of the use of hypothermia (cooling the body) for treatment of acute spinal cord injury (SCI). While early investigations evaluated the beneficial effects of more profound levels of local hypothermia treatment following SCI, recent studies have concentrated on the benefits of mild hypothermia in protecting and promoting functional recovery in animal (rat) models. In these studies, early cooling strategies improved locomotive function as well as forelimb gripping strength and coordination. In a small human study (14 subjects), modest hypothermia was found to be safe in severely injured SCI patients. Larger studies are needed to determine if therapeutic hypothermia is safe and beneficial in large numbers of SCI patients.
Dietrich, W Dalton III PhD
Crit Care Med. 2009 Jul;37(7 Suppl):S238-42.
[Return to top]
Spasticity
Clinical and neurophysiologic assessment of strength and spasticity during intrathecal baclofen titration in incomplete spinal cord injury: single-subject design.
Spasticity after spinal cord injury (SCI) is commonly managed with oral and intrathecal baclofen (ITB) (baclofen delivered directly into the cerebrospinal fluid surrounding the spinal cord by means of a catheter connected to a battery-powered pump implanted in the abdominal wall). The effects of ITB on strength and voluntary muscle activation have been largely ignored because most users have either (1) complete SCI or (2) incomplete SCI with only traces of voluntary movements and need ITB to manage spasticity that interferes with self-care or transfers. For a subset of patients who rely on residual motor control for functional mobility such as walking, there may be a fine balance between controlling spasticity and maintaining strength. This study evaluated the effects of varying doses of oral baclofen and ITB on clinical and neurophysiologic measures of strength and spasticity in a patient with an incomplete SCI. Results showed that control of spasticity can be achieved without reducing strength in incomplete SCI and suggests the need for including strength testing in comprehensive clinical assessment of spasticity.
Bowden M, Stokic DS.
J Spinal Cord Med. 2009;32(2):183-90.
[Return to top]
Assistive technology
Evaluation of Tooth-Click Triggering and Speech Recognition in Assistive Technology for Computer Access.
The Tooth-click (TC) detector is a small lightweight device that fits around the ear and senses jaw vibrations when teeth are clicked together. When paired with an optical or gyrometer head mouse, it may be used to control cursor movement and mouse button clicks. This study compared the effectiveness of TC to speech recognition (SR) and compared an optical head mouse (OHM) to a gyrometer head mouse (GHM) for cursor and mouse button control of a computer. Three individuals with tetraplegia and six able-bodied controls used the devices in four combinations (TC/OHM, TC/GHM, SR/OHM and SR/GHM) to perform specific tasks involving cursor movements and mouse clicks. TC was found to be significantly faster than SR in generating mouse button clicks when paired with either type of head mouse device. Such a system may improve computer access for people with tetraplegia. The study also found that with only five minutes of training, people with tetraplegia using TC paired with either OHM or GHM could achieve cursor movement and button clicking faster than an able-bodied person using a standard mouse.
Simpson T, Gauthier M, Prochazka A
Neurorehabil Neural Repair. 2009 Aug 13.
[Return to top]
Walking
Development of hybrid orthosis for standing, walking, and stair climbing after spinal cord injury.
This study explores the feasibility of a hybrid system of exoskeletal bracing and multichannel functional electrical stimulation (FES) to facilitate standing, walking, and stair climbing after spinal cord injury (SCI). The orthotic components consist of electromechanical joints that lock and unlock automatically to provide upright stability and free movement powered by FES. New orthotic components, including a variable constraint hip mechanism, were designed, prototyped and successfully tested on nondisabled volunteers and an individual with SCI. The power requirements are low enough to provide more than 4 hours of continuous operation with standard camcorder batteries. Further refinements of the mechanism and additional orthotic components for the trunk, knees and ankles need to be completed before this type of system can be a practical option for persons with SCI.
Kobetic R, To CS, Schnellenberger JR, et al.
J Rehabil Res Dev. 2009;46(3):447-62.
Whole-body vibration improves walking function in individuals with spinal cord injury: A pilot study.
Whole-body vibration (WBV)—in which subjects stand on a vibration platform for short periods—has improved walking in elderly individuals and individuals with Parkinson’s disease in previous research. This study involved 17 individuals (14 men, 3 women; age 28–65) with motor-incomplete SCI of at least one year duration. All had the ability to rise from sitting to standing with no more than moderate assistance from one person, and ability to stand (using upper extremity support) for at least one minute. They also had asymmetrical leg strength. Subjects received WBV sessions three days/week for four weeks. After the 12-session intervention, there were significant improvements in walking speed, cadence and other walking parameters. All subjects tolerated the intervention, were able to maintain the standing posture for the 45-second bouts of WBV, and reported no adverse effects. Improvements in walking speed were comparable to improvements associated with locomotor training. These findings suggest that regular use of WBV may be a potent intervention for improving walking function in individuals with incomplete SCI.
Ness LL, Field-Fote EC.
Gait Posture. 2009 Jul 31.
[Return to top]
Pressure ulcer prevention
Comparative study of pressure distribution at the user-cushion interface with different cushions in a population with spinal cord injury.
Wheelchair cushions for people with SCI are used to redistribute pressure in the seating area and reduce the risk of developing pressure ulcers. While consensus is lacking on what is the critical pressure at which pressure ulcers develop, the general recommendation is that skin should be subjected to the lowest possible pressure. In this study, a user-cushion pressure-recording system was used for assessing the mechanical characteristics of different types of wheelchair seat cushions. Each one of 48 patients with spinal cord injury was seated in his or her own wheelchair on the four models of cushions analyzed (low-profile air, high-profile air, dual-compartment air, and gel and firm foam), which were presented in randomized order. The pressure distribution readings and support surface area of the user-cushion interface were obtained. The dual-compartment air cushion was found to have the best pressure distribution and largest contact surface of the user-cushion interface compared to the other three cushions studied.
Gil-Agudo A, De la Peña-González A, Del Ama-Espinosa A, et al.
Clin Biomech (Bristol, Avon). 2009 Aug;24(7):558-63.
[Return to top]
Bowel management
Effect of sacral anterior root stimulator on bowel dysfunction in patients with spinal cord injury.
The sacral anterior root stimulator (SARS) has been used for neurogenic bladder, and there have been indications that it also may be useful for neurogenic bowel. In this study, 18 patients were evaluated for bowel function before and 12 months after receiving an SARS implant. Results showed that SARS improved constipation, increased the frequency of defecation, reduced time spent on defecation, and reduced the number of methods used to achieve evacuation. Most patients reported being more satisfied with bowel function after implantation of the SARS. However, further studies focused on the characteristics of stimulation parameters are required to obtain better results.
Vallès M, Rodríguez A, Borau A, Mearin F.
Dis Colon Rectum. 2009 May;52(5):986-92.
[Return to top]
Neurological change
Conversion in ASIA Impairment Scale during the first year after traumatic spinal cord injury.
When new therapeutic approaches to spinal cord repair and regeneration move from animal studies to human clinical trials, it will be important to understand the exact time course of spontaneous recovery in order to assess the effectiveness of new therapies. The aim of this study was to assess the extent and timing of the natural course of neurological change after injury, particularly of the American Spinal Injury Association (ASIA) Impairment Scale (AIS), within the first year after traumatic SCI. Data were derived from a multicenter cohort at five fixed time points after injury: within the first 15 days and at one, three, six and twelve months post injury. About 72% of the SCI subjects, who were classified within the first 15 days as AIS A were still classified as AIS A at 6 months. While 16% of the AIS A subjects converted (changed) to AIS B, only a few became motor incomplete. In contrast, only a quarter of the AIS B subjects remained AIS B, and most of them converted to AIS C and D. Over 70% of the AIS C subjects converted to AIS D, while almost 90% of the AIS D did not convert. The natural rate of neurological change that occurs in the first year in patients treated with standard therapies needs to be considered when planning clinical trials as well as when assessing the effectiveness of new regeneration-inducing therapies.
Spiess MR, Mueller RM, Rupp R, et al.
J Neurotrauma. 2009 May 20.