Chester H. Ho

Clinical Applications of Electrical Stimulation After Spinal Cord Injury

Abstract Summary: During the last one-half century, electrical stimulation has become dinically significant for improving health and restoring useful function afterspinal cord injury. Short-term stimulation can be provided by electrodes on the skin or percutaneous fine wires, but implanted systems are preferable for long-term use. Electrical stimulation of intact lower motor neurons can exercise paralyzed musdes and reverse wasting; improve strength, endurance, and cardiovascular fitness; and may reduce the progression of osteoporosis. Other potential therapeutic uses being investigated indude reduction of spasticity, prevention of deep vein thrombosis, and improvement of tissue health. Pacing of intact phrenic nerves in high tetraplegia can produce effective respiration without mechanical ventilation, allowing improved speech, increased mobility, and increased sense of well-being. lmprovement of cough has also been demonstrated. Stimulation of intact sacral ne.rves can produce effective micturition and reduce urinary tract infection; it can also improve bowel function and erection. lt is usually combined with posterior sacral rhizotomy to improve continence and bladder capacity, and the combination has been shown to reduce costs of care. Electroejaculation can now produce semen in most men with spinal cord injury. Significant achievements have also been made in restoring limb function . Useful hand grasp can be provided in CS and C6 tetraplegia, reducing dependence on adapted equipment and assistants. Standing, assistance with transfers, and walking for short distances can be provided to selected persons with paraplegia, improving their access to objects, places, and opportunities that are inaccessible from a wheelchair. This review summarizes the current state of therapeutic and neuroprosthetic applications of electrical stimulation afterspinal cord injury and identifies some future directions of research and dinical and commercial development.

Walking after incomplete spinal cord injury using an implanted FES system: a case report.

Implanted functional electrical stimulation (FES) systems for walking are experimentally available to individuals with incomplete spinal cord injury (SCI); however, data on short-term therapeutic and functional outcomes are limited. The goal of this study was to quantify therapeutic and functional effects of an implanted FES system for walking after incomplete cervical SCI. After robotic-assisted treadmill training and overground gait training maximized his voluntary function, an individual with incomplete SCI (American Spinal Injury Association grade C, cervical level 6-7) who could stand volitionally but not step was surgically implanted with an 8-channel receiver stimulator and intramuscular electrodes. Electrodes were implanted bilaterally, recruiting iliopsoas, vastus intermedius and lateralis, tensor fasciae latae, tibialis anterior, and peroneus longus muscles. Twelve weeks of training followed limited activity post-surgery. Customized stimulation patterns addressed gait deficits via an external control unit. The system was well-tolerated and reliable. After the 12-week training, maximal walking distance increased (from 14 m to 309 m), maximal walking speed was 10 times greater (from 0.02 m/s to 0.20 m/s), and physiological cost index was 5 times less (from 44.4 beats/m to 8.6 beats/m). Voluntary locomotor function was unchanged. The implanted FES system was well-tolerated, reliable, and supplemented function, allowing the participant limited community ambulation. Physiological effort decreased and maximal walking distance increased dramatically over 12 weeks.

Functional Electrical Stimulation and Spinal Cord Injury

Spinal cord injuries (SCI) can disrupt communications between the brain and the body, resulting in loss of control over otherwise intact neuromuscular systems. Functional electrical stimulation (FES) of the central and peripheral nervous system can use these intact neuromuscular systems to provide therapeutic exercise options to allow functional restoration and to manage medical complications following SCI. The use of FES for the restoration of muscular and organ functions may significantly decrease the morbidity and mortality following SCI. Many FES devices are commercially available and should be considered as part of the lifelong rehabilitation care plan for all eligible persons with SCI.

The mechanisms and evidence of efficacy of electrical stimulation for healing of pressure ulcer: A systematic review

The objective of this article is to provide a systematic review of the efficacy of electrical stimulation in healing pressure ulcer and to review its mechanism of action. The Cochrane Library, PubMed, CINAHL, Medline, EMBASE, and NHS EED were searched for relevant interventional studies including randomized controlled trials (RCTs) and observational studies. A best‐evidence synthesis was performed to summarize the results of the included studies. A total of seven RCTs and two observational studies met the inclusion criteria. Moderate level of evidence of efficacy with low risk of bias was shown in all seven RCTs. Although some studies have used continuous direct current, most other investigators opted to use high‐voltage pulsed current to minimize the risk of skin burn and to achieve greater current penetration. Overall, the incidence of adverse effects was very low. Two studies that assessed the economic impacts of electrical stimulation revealed substantial health care cost savings. The mechanisms through which electrical stimulation exerts a positive effect on pressure ulcer healing are reasonably well established. Clinical trials have revealed a moderate level of evidence to support its use as an ancillary treatment modality for healing pressure ulcer. Recommendations regarding the optimal electrical stimulation parameters and dosage of use are provided. Further studies to investigate potential barriers that may impede widespread use in different clinical settings are needed.

Minimizing Errors in Acute Traumatic Spinal Cord Injury Trials by Acknowledging the Heterogeneity of Spinal Cord Anatomy and Injury Severity: An Observational Canadian Cohort Analysis

Clinical trials of therapies for acute traumatic spinal cord injury (tSCI) have failed to convincingly demonstrate efficacy in improving neurologic function. Failing to acknowledge the heterogeneity of these injuries and under-appreciating the impact of the most important baseline prognostic variables likely contributes to this translational failure. Our hypothesis was that neurological level and severity of initial injury (measured by the American Spinal Injury Association Impairment Scale [AIS]) act jointly and are the major determinants of motor recovery. Our objective was to quantify the influence of these variables when considered together on early motor score recovery following acute tSCI. Eight hundred thirty-six participants from the Rick Hansen Spinal Cord Injury Registry were analyzed for motor score improvement from baseline to follow-up. In AIS A, B, and C patients, cervical and thoracic injuries displayed significantly different motor score recovery. AIS A patients with thoracic (T2-T10) and thoracolumbar (T11-L2) injuries had significantly different motor improvement. High (C1-C4) and low (C5-T1) cervical injuries demonstrated differences in upper extremity motor recovery in AIS B, C, and D. A hypothetical clinical trial example demonstrated the benefits of stratifying on neurological level and severity of injury. Clinically meaningful motor score recovery is predictably related to the neurological level of injury and the severity of the baseline neurological impairment. Stratifying clinical trial cohorts using a joint distribution of these two variables will enhance a studys chance of identifying a true treatment effect and minimize the risk of misattributed treatment effects. Clinical studies should stratify participants based on these factors and record the number of participants and their mean baseline motor scores for each category of this joint distribution as part of the reporting of participant characteristics. Improved clinical trial design is a high priority as new therapies and interventions for tSCI emerge.

Poor nutrition is a relative contraindication to negative pressure wound therapy for pressure ulcers: preliminary observations in patients with spinal cord injury.

OBJECTIVE: To assess the efficacy of negative-pressure wound therapy (NPWT) for healing of pressure ulcers (PrUs) in individuals with spinal-cord injury (SCI). DESIGN: Multicenter, 28-day observational study. SETTING: Ten Veterans Affairs Medical Center SCI centers. PATIENTS: Eighty-six SCI inpatients with Stage III/IV pelvic PrUs. INTERVENTIONS: Standard wound care with NPWT versus standard wound care alone (NoNPWT). MAIN OUTCOME MEASURES: Change in wound surface area (WSA) using the Verg Videometer Measurement Documentation software. MAIN RESULTS: The proportion of patients demonstrating a decrease in WSA (healing subgroup) was not significantly different between the NPWT (n = 33) and NoNPWT (n = 53) groups (67% vs 70%, respectively). In the healing subgroup, there was no significant difference between the NPWT versus NoNPWT groups in WSA decrease (−43 ± 22% vs −50% ± 26%, not statistically significant). Similarly, in the nonhealing subgroup, there was no significant difference between NPWT and NoNPWT groups (31% ± 26% vs 32% ± 34%). In the NPWT group, the nonhealing subgroup (11/33) had significantly lower serum albumin levels than the healing subgroup (22/33) (2.9 ± 0.4 vs 3.3 ± 0.5 mg/dL, P < .05). In the NoNPWT group, there was no significant difference in serum albumin levels between the healing versus nonhealing subgroups (3.2 ± 0.3 vs 3.2 ± 0.3 mg/dL). CONCLUSION: In SCI patients with Stage III/IV pelvic PrUs, NPWT did not significantly influence the rate of healing. Additionally, in malnourished individuals (albumin <3.0 mg/dL), NPWT was not efficacious. Healing outcomes in the NPWT group were significantly influenced by albumin levels, whereas no such disparity was noted between the healing and nonhealing PrUs for the NoNPWT group. Nutritional status appears to be important in the effectiveness of NPWT.

The use of sensory electrical stimulation for pressure ulcer prevention.

Pressure ulcer prevention is critically important for many people with reduced mobility. The authors investigated whether sensory (sub-motor-threshold) electrical stimulation (ES) may provide a convenient preventive intervention. A double-blinded, repeated measures study design was used to test the hypothesis that repeated use of sensory surface ES improves tissue health status in individuals with motor paralysis. Six adult males with complete spinal cord injury (SCI) were randomly assigned to treatment or control groups. The treatment group received the ES intervention, whereas the control group received a control sham intervention. Repeated tissue health assessments included transcutaneous oxygen tension (TcPO2), interface pressure mapping, and gluteal computed tomography (CT) studies. An initial increase in TcPO2 following use of subthreshold ES was observed but was not sustained at follow-up. No statistically significant changes before and after treatment were found in regional TcPO2, gluteal muscle area or pressure distribution. Thus subthreshold ES does not appear to have any sustained effects on tissue health status indicative of reduced pressure ulcer risk for individuals with SCI. This implies that a contractile muscle response is critically important and further that subthreshold ES is unlikely to prevent pressure ulcers. Further studies are needed to find solutions for preventing pressure ulcers in high-risk populations.

A Novel Topical Oxygen Treatment for Chronic and Difficult-to-Heal Wounds: Case Studies

Abstract Background: Pressure ulcers are one of the most prevalent causes of morbidity in patients with spinal cord injury (SCI). For those requiring hospital-based management, conventional wound management may necessitate a prolonged institutional stay. This may subsequently increase the likelihood of comorbidities and increase the social, psychological, and financial burdens associated with wound management. Therefore, novel adjunct treatments that potentiate improved healing rates should be seriously considered. Study Design: Case reports. Objective: To observe the efficacy of the EpiFLO device as an adjunct treatment modality in chronic wound management. Setting: An SCI unit at a Veterans Affairs Medical Center. Methods: Three men with SCI, who each presented with a stage IV pressure ulcer in the pelvic region, were treated with the EpiFLO device as an adjunct therapy. In Case 1, the patient was monitored for 9 weeks, whereas in Cases 2 and 3, the patients were monitored for 5 weeks. Healing was determined on a weekly basis by wound dimensions and volume, which were compared before and after the intervention. Results: Comparison of pre- and posttreatment outcome measurements showed significant improvement with EpiFLO in each case. Conclusion: EpiFLO seems to have had a positive effect on the healing rate of chronic pressure ulcers in individuals with SCI.

Best practices for the treatment and prevention of urinary tract infection in the spinal cord injured population

The purpose of this review of clinical guidelines and best practices literature is to suggest prevention options and a treatment approach for intermittent catheter users that will minimize urinary tract infections (UTI). Recommendations are based both on evidence in the literature and an understanding of what is currently attainable within the Alberta context. This is done through collaboration between both major tertiary care centres (Edmonton and Calgary) and between various professionals who regularly encounter these patients, including nurses, physiatrists and urologists.

Physiological measurements of tissue health; implications for clinical practice

Pressure mapping alone insufficiently describes tissue health. Comprehensive, quantitative non invasive assessment is crucial. Interface pressures (IPs) and transcutaneous blood gas levels [transcutaneous tissue oxygen (TcPO2)] were simultaneously assessed over both ischia and the sacrum to investigate the hypotheses: (i) tissue oxygenation decreases with sustained applied pressure; (ii) tissue oxygen and IP are inversely correlated in loaded soft tissues; (iii) multisite assessments are unnecessary because healthy individuals are symmetrical. Measurements were taken at 5‐minute intervals for 20 minutes in both sitting and supine lying for a cohort of 20 able‐bodied adults. There were no statistically significant changes over time for either variable in 96% of timepoint comparisons. Specifically, no significant differences were seen between 10 and 20 minutes in either position. These findings imply that a 10‐minute assessment can reliably indicate tissue health and that tissue may adapt to applied load over time. No statistically significant correlations between TcPO2 and IP were observed. However, the left and right ischia were significantly different for both variables in supine lying (P < 0·001) and for sitting IP (P < 0·010). Thus, even in this healthy cohort, postural symmetry was not observed and should not be assumed for other populations with restricted mobility. If a multisite technique cannot be used, repeated tissue health assessments must use the same anatomic location.