The Effect of Exoskeletal-Assisted Walking on Spinal Cord Injury Bowel Function: Results from a Randomized Trial and Comparison to Other Physical Interventions

Bowel function after spinal cord injury (SCI) is compromised because of a lack of voluntary control and reduction in bowel motility, often leading to incontinence and constipation not easily managed. Physical activity and upright posture may play a role in dealing with these issues. We performed a three-center, randomized, controlled, crossover clinical trial of exoskeletal-assisted walking (EAW) compared to usual activity (UA) in people with chronic SCI. As a secondary outcome measure, the effect of this intervention on bowel function was assessed using a 10-question bowel function survey, the Bristol Stool Form Scale (BSS) and the Spinal Cord Injury Quality of Life (SCI-QOL) Bowel Management Difficulties instrument. Fifty participants completed the study, with bowel data available for 49. The amount of time needed for the bowel program on average was reduced in 24% of the participants after EAW. A trend toward normalization of stool form was noted. There were no significant effects on patient-reported outcomes for bowel function for the SCI-QOL components, although the time since injury may have played a role. Subset analysis suggested that EAW produces a greater positive effect in men than women and may be more effective in motor-complete individuals with respect to stool consistency. EAW, along with other physical interventions previously investigated, may be able to play a previously underappreciated role in assisting with SCI-related bowel dysfunction.

The design of a randomized control trial of exoskeletal-assisted walking in the home and community on quality of life in persons with chronic spinal cord injury

There are more than 300,000 estimated cases of spinal cord injury (SCI) in the United States, and approximately 27,000 of these are Veterans. Immobilization from SCI results in adverse secondary medical conditions and reduced quality of life. Veterans with SCI who have completed rehabilitation after injury and are unable to ambulate receive a wheelchair as standard of care. Powered exoskeletons are a technology that offers an alternative form of limited mobility by enabling over-ground walking through an external framework for support and computer-controlled motorized hip and knee joints. Few studies have reported the safety and efficacy for use of these devices in the home and community environments, and none evaluated their impact on patient-centered outcomes through a randomized clinical trial (RCT). Absence of reported RCTs for powered exoskeletons may be due to a range of challenges, including designing, statistically powering, and conducting such a trial within an appropriate experimental framework. An RCT for the study of exoskeletal-assisted walking in the home and community environments also requires the need to address key factors such as: avoiding selection bias, participant recruitment and retention, training, and safety concerns, particularly in the home environment. These points are described here in the context of a national, multisite Department of Veterans Affairs Cooperative Studies Program-sponsored trial. The rationale and methods for the study design were focused on providing a template for future studies that use powered exoskeletons or other strategies for walking and mobility in people with immobilization due to SCI.

Mobility Skills With Exoskeletal-Assisted Walking in Persons With SCI: Results From a Three Center Randomized Clinical Trial

Background: Clinical exoskeletal-assisted walking (EAW) programs for individuals with spinal cord injury (SCI) have been established, but many unknown variables remain. These include addressing staffing needs, determining the number of sessions needed to achieve a successful walking velocity milestone for ambulation, distinguishing potential achievement goals according to level of injury, and deciding the number of sessions participants need to perform in order to meet the Food and Drug Administration (FDA) criteria for personal use prescription in the home and community. The primary aim of this study was to determine the number of sessions necessary to achieve adequate EAW skills and velocity milestones, and the percentage of participants able to achieve these skills by 12 sessions and to determine the skill progression over the course of 36 sessions.

Methods: A randomized clinical trial (RCT) was conducted across three sites, in persons with chronic (≥6 months) non-ambulatory SCI. Eligible participants were randomized (within site) to either the EAW arm first (Group 1), three times per week for 36 sessions, striving to be completed in 12 weeks or the usual activity arm (UA) first (Group 2), followed by a crossover to the other arm for both groups. The 10-meter walk test seconds (s) (10MWT), 6-min walk test meters (m) (6MWT), and the Timed-Up-and-Go (s) (TUG) were performed at 12, 24, and 36 sessions. To test walking performance in the exoskeletal devices, nominal velocities and distance milestones were chosen prior to study initiation, and were used for the 10MWT (≤ 40s), 6MWT (≥80m), and TUG (≤ 90s). All walking tests were performed with the exoskeletons.

Results: A total of 50 participants completed 36 sessions of EAW training. At 12 sessions, 31 (62%), 35 (70%), and 36 (72%) participants achieved the 10MWT, 6MWT, and TUG milestones, respectively. By 36 sessions, 40 (80%), 41 (82%), and 42 (84%) achieved the 10MWT, 6MWT, and TUG criteria, respectively.

Conclusions: It is feasible to train chronic non-ambulatory individuals with SCI in performance of EAW sufficiently to achieve reasonable mobility skill outcome milestones.

Aquatic, deep water peak VO2 testing for individuals with spinal cord injury

Objective: To determine the reliability of peak VO₂ testing for individuals with spinal cord injury (SCI) in deep water and on land; and to examine the relationship between these two testing conditions. Design: Reliability study. Setting: Comprehensive rehabilitation center in Baltimore, MD, USA. Participants: 17 participants (13 men, 4 women) with motor complete and incomplete SCI. Participants were randomized into either aquatic or arm cycle ergometer first measurements. Intervention: Pilot study to assess peak VO₂. Outcome measures: Peak VO₂ measured with metabolic cart in supported deep water with the addition of Aquatrainer® connection, and on land with arm cycle ergometer. Two trials were conducted for each condition with 48 h separating each test. Results: Peak oxygen consumption reliability was statistically significant for both conditions, aquatic (r = 0.93, P < 0.001) and arm cycle ergometry (r = 0.96, P < 0.001). Additionally, aquatic and arm cycle peak VO₂ correlation existed (r = 0.72, P < 0.001). For these 17 participants, lower extremity motor score influenced supported, deep water peak VO₂, B = 0.57, P < 0.02, whereas age, sex, and weight did not impact deep water or ergometer values. Conclusion: Determining peak VO₂ for individuals with SCI is highly reproducible for arm cycle ergometry and in deep water assessment. Additionally, aquatic, deep water peak VO₂ testing is valid when compared to arm cycle ergometry. Although the peak VO₂ relationship between deep water and arm cycle ergometry is high, variance in the two conditions does exist. Therefore, it is important to assess peak VO₂ via the same exercise modality utilized in the treatment intervention.

Auricular acupuncture for spinal cord injury related neuropathic pain: a pilot controlled clinical trial

OBJECTIVE

To obtain preliminary data on the effects of an auricular acupuncture protocol, Battlefield Acupuncture (BFA), on self-reported pain intensity in persons with chronic Spinal Cord Injury (SCI) and neuropathic pain.

DESIGN

Pilot randomized delayed entry single center crossover clinical trial at an outpatient rehabilitation and integrative medicine hospital center.

METHODS

Chronic (> one year post injury) ASIA impairment scale A through D individuals with SCI with injury level from C3 through T12 and below level neuropathic pain with at least five on the Numeric Rating Scale (NRS) were recruited. Twenty-four subjects were randomized to either an eight-week once weekly ten-needle BFA protocol (n = 13) or to a waiting list followed by the BFA protocol (n = 11).

OUTCOME MEASURES

The primary outcome measure was change in the pain severity NRS. Secondary outcome was the Global Impression of Change.

RESULTS

Demographically there were no significant differences between groups. Mean pain scores at baseline were higher in acupuncture than control subjects (7.75 ± 1.54 vs. 6.25 ± 1.04, P = 0.027). Although both groups reported significant reduction in pain during the trial period, the BFA group reported more pain reduction than the delayed entry group (average change in NRS at eight weeks -2.92 ± 2.11 vs. -1.13 ± 2.14, P = 0.065). There was a significant difference in groups when a group-by-time interaction in a mixed-effect repeated measures model (P = 0.014).

CONCLUSION

This pilot study has provided proof of concept that BFA has clinically meaningful effect on the modulation of SCI neuropathic pain.

Robotically assisted treadmill exercise training for improving peak fitness in chronic motor incomplete spinal cord injury: A randomized controlled trial

OBJECTIVE

To assess the effectiveness of robotically assisted body weight supported treadmill training (RABWSTT) for improving cardiovascular fitness in chronic motor incomplete spinal cord injury (CMISCI).

DESIGN

Pilot prospective randomized, controlled clinical trial.

SETTING

Outpatient rehabilitation specialty hospital.

PARTICIPANTS

Eighteen individuals with CMISCI with American Spinal Injury Association (ASIA) level between C4 and L2 and at least one-year post injury. Interventions CMISCI participants were randomized to RABWSTT or a home stretching program (HSP) three times per week for three months. Those in the home stretching group were crossed over to three months of RABWSTT following completion of the initial three month phase.

OUTCOME MEASURES

Peak oxygen consumption (peak VO(2)) was measured during both robotic treadmill walking and arm cycle ergometry: twice at baseline, once at six weeks (mid-training) and twice at three months (post-training). Peak VO(2) values were normalized for body mass.

RESULTS

The RABWSTT group improved peak VO(2) by 12.3% during robotic treadmill walking (20.2 ± 7.4 to 22.7 ± 7.5 ml/kg/min, P = 0.018), compared to a non-significant 3.9% within group change observed in HSP controls (P = 0.37). Neither group displayed a significant change in peak VO2 during arm cycle ergometry (RABWSTT, 8.5% (P = 0.25); HSP, 1.76% (P = 0.72)). A repeated measures analysis showed statistically significant differences between treatments for peak VO(2) during both robotic treadmill walking (P = 0.002) and arm cycle ergometry (P = 0.001).

CONCLUSION

RABWSTT is an effective intervention model for improving peak fitness levels assessed during robotic treadmill walking in persons with CMISCI.

Atypical autonomic dysreflexia during robotic-assisted body weight supported treadmill training in an individual with motor incomplete spinal cord injury

CONTEXT/OBJECTIVE

A 41-year-old man with a history of C6 American Spinal Injury Association (ASIA) Impairment Scale (AIS) C spinal cord injury (SCI), enrolled in an Institutional Review Board (IRB)-approved, robotic-assisted body weight-supported treadmill training (BWSTT), and aquatic exercise research protocol developed asymptomatic autonomic dysreflexia (AD) during training. Little information is available regarding the relationship of robotic-assisted BWSTT and AD.

FINDINGS

After successfully completing 36 sessions of aquatic exercise, he reported exertional fatigue during his 10th Lokomat intervention and exhibited asymptomatic or silent AD during this and the three subsequent BWSTT sessions. Standard facilitators of AD were assessed and no obvious irritant identified other than the actual physical exertion and positioning required during robotic-assisted BWSTT.

CONCLUSIONS/CLINICAL RELEVANCE

Increased awareness of potential silent AD presenting during robotic assisted BWSTT training for individuals with motor incomplete SCI is required as in this case AD clinical signs were not concurrent with occurrence. Frequent vital sign assessment before, during, and at conclusion of each BWSTT session is strongly recommended.

The review of systems in spinal cord injury and dysfunction

Individuals with spinal cord injury or dysfunction represent unique diagnostic challenges when they present with symptoms of generalized malaise or "feeling lousy." Those individuals with injury or dysfunction at or above the T6 level are specifically at risk for the phenomenon known as autonomic dysreflexia, which is a medical emergency. The underlying cause of autonomic dysreflexia as well as other secondary complications in the patient with a spinal cord injury can best be uncovered through a comprehensive review of systems, which encompasses constitutional, head, cardiovascular, gastrointestinal, genitourinary, musculoskeletal, respiratory, skin, neurologic, psychiatric, endocrinologic, hematologic, and immunologic issues.

Unilateral hyperhidrosis from a contralateral source in an individual with C4 complete tetraplegia

SETTING

Outpatient clinic of a spinal cord injury rehabilitation center.

DESIGN

Case report.

PARTICIPANT

A 40-year-old man with a 20-year history of C4 complete tetraplegia complained of 5 years of excessive intermittent left-sided sweating. The sweating occurred only in the seated upright position. There was no associated headache, blurred vision, or blood pressure variability.

FINDINGS

When examined upright, the patient sweated excessively on the left face and body. When he was laid down, sweating ceased. Skin examination revealed intact ischial regions. Pressure applied to the right ischium for several minutes caused sweating to recur on the left forehead, but it then subsided with release of pressure. This phenomenon was repeatable. Local lidocaine injection in the subcutaneous tissues around the right ischium and subsequent use of lidocaine transdermal patches halted the contralateral sweating in the upright position. Pressure mapping analysis showed increased pressure in the region of the right ischial tuberosity. The patient's gel cushion was replaced with an air-filled cushion, providing significant ongoing relief from the hyperhidrosis.

CONCLUSION/CLINICAL RELEVANCE

Unilateral hyperhidrosis can be caused by a contralateral source of irritation. Use of techniques that interrupt the afferent arm of the autonomic pathway may be effective in the management of hyperhidrosis in individuals with spinal cord injury.

Staphylococcus aureus colonization in community-dwelling people with spinal cord dysfunction

OBJECTIVES

To estimate the prevalence of and determine risk factors for Staphylococcus aureus colonization of the perineum.

DESIGN

Cross-sectional study with follow-up of up to 1 year.

SETTING

Multiple outpatient sites.

PARTICIPANTS

Eighty-four community-dwelling adults with spinal cord dysfunction (SCD).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Colonization of perineum with S. aureus.

RESULTS

Overall, 24% of the study cohort carried S. aureus on their perineal skin at enrollment, with 16% having methicillin-susceptible S. aureus and 10% having methicillin-resistant S. aureus (MRSA). Most perineal carriers were also colonized in the anterior nares. Participants with trauma as the cause of their SCD were more likely to be colonized with S. aureus than participants with SCD caused by multiple sclerosis or other causes (relative risk [RR], 2.8; 95% confidence interval [CI], 1.2-6.6; P=.01). Participants with pelvic decubiti were more likely to be colonized with S. aureus than participants without pelvic decubiti (RR=4.3; 95% CI, 2.4-7.7; P<.001). The recent use of any antibiotic was not associated with an increased risk of colonization with S. aureus (RR=1.5; 95% CI, 0.7-3.3; P=.31); however, recent fluoroquinolone use was significantly associated with perineal colonization (RR=2.8; 95% CI, 1.4-5.8; P=.02). Of the 8 participants with MRSA colonization, only 2 (25%) had a history of MRSA colonization.

CONCLUSIONS

S. aureus colonization of the perineum is common in this outpatient population of people with SCD. The use of fluoroquinolones was associated with S. aureus colonization. Colonization with MRSA without a history of MRSA was common.

Prevalence and Natural History of Colonization With Fluoroquinolone-Resistant Gram-Negative Bacilli in Community-Dwelling People With Spinal Cord Dysfunction

OBJECTIVES

To estimate the prevalence of colonization with fluoroquinolone-resistant gram-negative bacilli (GNB) and to assess risk factors for and define the natural history of colonization.

DESIGN

Cross-sectional study with follow-up of up to 1 year.

SETTING

Multiple outpatient sites.

PARTICIPANTS

Eighty-four community-dwelling adults with spinal cord dysfunction.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Colonization of perineum with fluoroquinolone-resistant GNB.

RESULTS

Overall, 24% of this community-dwelling cohort was colonized with fluoroquinolone-resistant GNB with resistance to both levofloxacin and gatifloxacin. The use of any antibiotic in the last 90 days was most strongly associated with an increased risk of colonization with fluoroquinolone-resistant GNB (relative risk, 2.3; 95% confidence interval, 1.1-4.8; P=.05). Incontinence was significantly more common among those with fluoroquinolone-resistant GNB colonization. Among the participants with incontinence (n=42), the use of intermittent catheterization (vs suprapubic, urethral, or condom catheters or overflow incontinence) was significantly protective. Colonization was not associated with an increase in urinary tract infection and was often transient.

CONCLUSIONS

Fluoroquinolone resistance among GNB colonizing community-dwelling people with spinal cord dysfunction is common. Colonization is more common among those receiving antibiotics and less common among those continent of urine. Among those with incontinence, those using intermittent catheterization have less colonization.

An update on functional electrical stimulation after spinal cord injury

Recent advances in biomedical engineering as applied to neurologic rehabilitation have finally borne clinically relevant fruit. Nowhere is this more evident than in the field of functional electrical stimulation (FES). This article highlights the remarkable clinical progress that has been made in the use of electrical stimulation for restoring movement and function in individuals with spinal cord injury. Specific attention is given to respiratory-assist devices, hand-grasp systems, standing and walking, and bladder control. This review article features discussion of eight devices that have gone through the United States Food and Drug Administration (FDA) regulatory approval process.

Influence of training on biomechanics of wheelchair propulsion

A quasi-experimental longitudinal design was used to compare pre- and posttraining biomechanical and physiological characteristics of wheelchair propulsion in manual wheelchair users (MWCU) across fresh and fatigue states. An instrumented wheelchair ergometer, 3D motion analysis, and computerized open-circuit spirometry were used to collect joint kinetics and kinematics, handrim kinetics, propulsion temporal characteristics, and oxygen uptake pre- and posttraining during a submaximal exercise test to exhaustion. Each subject (n = 19) participated in a specific intervention program of supervised therapeutic exercise (strengthening, stretching, and aerobic exercise) for 6 weeks. Pre- and posttraining measurements were compared with the use of ANOVA with repeated measures. Significant training effects included increased exercise loads for all strengthening activities, decreased stroke frequency, increased maximum elbow extension angle, increased trunk and shoulder flexion/extension range of motion (ROM), increased handrim propulsive moment, increased wrist extension moment, and increased power output. Results suggest that this training program increased biomechanical economy (as defined by propulsive moment) without increasing shoulder or elbow joint stresses.

Neurophysiologic evaluation of lower motor neuron damage in tetraplegia

We quantitatively investigated the extent of damage to motor neurons in tetraplegic subjects. Numbers of motor units in the patients were significantly lower for thenar, wrist extensor, and biceps brachii as compared to controls. Reduction in counts occurred even when M-response amplitudes were normal. Standard electromyography suggested a surprising frequency of lower motor neuron dysfunction below the level of injury. These results confirm previous reports and add data on motor units in the biceps brachii.

Patient selection for an upper extremity neuroprosthesis in tetraplegic individuals

One hundred and twenty persons with new onset traumatic tetraplegia consecutively admitted to our rehabilitation service were screened for consideration for use of an upper extremity neuroprosthesis. Strict inclusion criteria allowed only for participation of patients with ASIA impairment scale A, B or C injuries at the C5 or C6 level. One hundred and six persons were excluded from participation for the following reasons: five patients died, 27 had central cord syndrome, two had Brown-Sequard syndrome, 12 were injured at too high a level, 42 were injured at too low a level, two were excluded on the basis of motor incompleteness alone, four were excessively denervated, two had limited range of motion, one had overriding medical complications, seven had psychosocial issues making participation impractical, and two elected tendon transfer surgery. In total, 14 patients (representing 11.7% of all tetraplegic individuals and 50% of the C5 or C6 ASIA Impairment Scale A, B or C patients) were found to be candidates for the neuroprosthesis. Given the prevalence of tetraplegia, approximately 12,200 Americans would be candidates for the FES neuroprosthetic hand grasp system under the current research protocols. With both the expansion of current protocols to other diagnostic categories and further research and development, application of this neuroprosthesis to a considerable number of previously excluded subjects will likely be possible.

Nonlinear stretch reflex interaction during cocontraction

1. We investigated the role of stretch reflexes in controlling two antagonist muscles acting at the interphalangeal joint in the normal human thumb. Reflex action was compared when either muscle contracted alone and during cocontraction. 2. The total torque of the flexor pollicis longus (FPL) and extensor pollicis longus (EPL) muscles was measured in response to an externally imposed extension of the interphalangeal joint. The initial joint angle and the amplitude of the extension were constant in all experiments, and the preload of the active muscle(s) was varied. Joint torque was measured at the peak of short-latency stretch reflex action during contraction of the FPL alone, contraction of the EPL alone, and during cocontraction. Incremental joint stiffness was calculated as the change in torque divided by the change in angle. 3. Incremental stiffness increased in proportion to the preload torque during single muscle contractions of either the FPL (lengthening disturbances) or the EPL (shortening disturbances). Thus stiffness was not regulated to a constant value in the face of varying loads for either single muscle stretch or release. 4. Incremental stiffness varied across the range of cocontraction levels while the net torque was maintained at approximately 0. Thus net torque alone did not determine the stiffness during cocontraction. 5. The contributions of each muscle to the net intrinsic torque during cocontraction were estimated by scaling the individual muscles' responses so that their sum gave the best fit (in a least-squares sense) to the cocontraction torque before reflex action. The solution is unique because the individual torques have opposite signs, but the stiffnesses add. This gave estimates of the initial torques of both muscles during cocontraction. 6. The contributions of the two muscles during cocontraction were used to estimate the active joint stiffness that would be expected if the two muscles were activated independently to the same levels as in the cocontraction trials. The stiffness measured at the peak of stretch reflex action during cocontraction trials differed from the sum of the stiffnesses of the two muscles when they were contracting alone. At low cocontraction levels, the measured stiffness was less than expected on the basis of summation of the action of the two muscles, whereas at high cocontraction levels, the measured stiffness was greater than expected. This demonstrates that there is nonlinear stretch reflex interaction. That is, reflex action for a pair of antagonists is not simply the linear sum of the reflex actions of the two muscles acting independently.(ABSTRACT TRUNCATED AT 400 WORDS)

Upper extremity applications of functional neuromuscular stimulation

Functional electrical stimulation (FES) has been used for increasing muscle strength, decreasing spasticity, and controlling movement of limbs for many years. Most of this work, however, has been done in a research setting. Over the past decade, FES has moved slowly from the laboratory to the clinical world through feasibility studies in groups of patients with spinal cord injuries and strokes. Electrical stimulation has been shown to decrease spastic tone both during and after the stimulation, allowing for better limb positioning, decrease in contracture formation, and in some cases, improvement of voluntary movement. Electrical stimulation as a motor prosthesis is now being provided to small groups of spinal cord-injured patients (primarily C4, C5 and C6 levels) to assist with hand positioning and to produce hand grasp. In these settings, patients have attained greater independence in activities of daily living and in work-related tasks. Distribution of this technology to multiple centers is continuing through a technology transfer program.

Intramedullary and extramedullary schwannoma of the cervical spinal cord--case report

Intramedullary schwannomas and neurofibromas are rare tumors. Only two cases have been reported as having both an intramedullary and extramedullary component. We have managed the case of a 15-year-old girl with a schwannoma that appeared to track along the sensory nerve root into the spinal cord. The clinical presentation in this case was that of motor weakness and atrophy, sensory abnormalities, and, late in the course, pain. Magnetic resonance imaging with gadolinium enhancement was better than myelography and computed tomography at delineating the intramedullary extent of the tumor. The tumor was removed microsurgically at two operative sittings. Reports of this unusual pathology are reviewed.