Supporting evidence for FES Cycling.
Background:
The impact of a spinal cord injury (SCI) is not restricted to the obvious paralysis and
sensory loss which affects a patient’s mobility, self-care, and Activities of Daily Living
independence. The patient with SCI also experiences significant changes in body
composition and organ system physiology which places them at increased risk for a
variety of health complications. These changes include the development of significant
spasticity, paralysis-related muscular atrophy, as well as impaired circulatory and
cardiovascular function. Because of the combined efforts of paralysis and spasticity,
persons with SCI are at significant risk for diminished range of motion in the lower
extremities which often leads to further functional limitations, postural deformities and
skin complications.
Studies have also shown in impairment of glucose metabolism (insulin resistance) with
an increase risk of Type II diabetes in the group of patients which is related to changes in
body composition following SCI. There is also a significant loss of bone mass in the
lower extremities of persons with SCI which has been associated with an increased
incidence of pathological fractures. These changes and the added risk for related
medical complications are the direct consequence of SCI and are costly to resolve
according to Devivo et al. (37)
Evidence basis for appropriateness of an FES system:
Persons with SCI are not only at increased risk for developing a variety of medical
complications which are costly to resolve, they have also lost the ability to participate in
an effective activity treatment program by virtue of their disability. There are over 70
peer reviewed published articles in the medical literature which have examined the
effects of electrically stimulated activity of the lower extremities in persons with SCI
paralysis.
Much of this research has focused on the medical benefits of Functional Electrical
Stimulation Cycle Ergometry (FES-CE) in which the paralyzed lower extremities are
made to actively pedal a stationary leg cycle ergometer against resistance. This is
accomplished by sophisticated computer-programmed electrical stimulation of key
musculature using surface electrodes. The electrical stimulation achieves strong,
coordinated muscle contractions in the legs (including gluteal muscles) which allow a
person to receive a therapeutic dosage of intensive movement and patterned neural
activity which person would not otherwise be able to obtain.
This body of literature has shown that routine use of FES-CE produces and active
training response effect (references 1-14), reverses disuse atrophy (4,9,11,14-18),
reduces patient reports of spasticity (19), maintains range of motion (4), and improves
circulatory responses (5,17,20-24). Persons with higher level SCI have shown an
improvement in myocardial atrophy with FES-CE (25).
Research on the metabolic consequences of FES-CE in patients with SCI has
demonstrated improvement in body composition (increased lean muscle mass)
associated with improved glucose tolerance testing (8,16,20,26,27). Cardiovascular
conditioning effects (5,7,22,28-30) and improved pulmonary function (15,22,30) have
also been demonstrated with FES-CE activity regimens. Some studies examining the
effect of FES-CE on bone mineral density have shown a beneficial effect (29-32). There
is also evidence of improved bone density in those patients treated with FES-CE who
can achieve higher activity outputs (30). A number of investigators have also studied the
psychological effects of FES-CE training and found improvement in body image (17-19)
and depression (36) measures.
More recent work has begun to also show additional important neurological effects.
McDonald et al (38) have reported on a 60 patient cohort study examining FES
ergometry in SCI compared to conventional therapy for individuals more that 1.5 years
from injury. The authors have reported that FES ergometry was associated with
significant improvements in physical integrity and functional recovery.
Thigh
(quadriceps) muscle mass was increased by an average of 30% while intra/intermuscular fat was reduced by 44%. Stimulated muscle strength was increased by 78%
while relative spasticity was simultaneously reduced by 47%. These effects were
specific with no differences observed in non-stimulated muscles. In parallel, the low
HDL and testosterone levels and impaired glucose tolerance of controls were normalized
in FES treatment subjects.
The average 10-point loss of ASIA motor-sensory scores in control subjects over three
years was offset in FES treatment subjects with an additional average 38-point observed
improvement. FES therapy was associated with a 70% responder rate. The 30% of FES
therapy subjects that did not recover function at least did not loose function. ASIA grade
conversion rates were 40% in FES therapy subjects compared to 4% in control subjects.
The FES therapy group required less antispasmodic drug treatment and a greater
percentage of FES therapy subjects were able to discontinue or reduce the dosage of
Baclofen required to control spasticity.
To summarize, FES-CE research in persons with SCI has demonstrated the ability of this
treatment to improve the “health impairment” that accompanies this disability.
Furthermore, the strengthening and better general health that comes with FES
ergometry will allow a person to better accomplish his activities of daily living.
Trunk stimulation
The RT300 system is the only FES cycling system that is capable of stimulating the
abdominal and erector spinae muscles while a person is either leg or arm cycling.
The lack of voluntary control of the trunk muscles can have serious functional and
health-related implications for those with SCI. The inability to vary seated posture or
maintain anything other than one passive stable position can lead to skeletal deformities,
increased risk for development of decubitus ulcers and imposition of large and
nonphysiological pressure on internal organs that may compromise their function. (40)
In healthy individuals, the erector spinae provide trunk extension and are the primary
means of achieving stability and balance of the head and trunk during sitting. After spinal
cord injury (SCI), paralysis of the erector spinae diminishes or eliminates voluntary trunk
control, leading to dramatic changes in seated posture and the ability to reach and grasp
objects bimanually. (41)
Less erect posture and poor support of the shoulder girdle complex limit production of
maximal upper limb force to push a wheelchair. Because most manual wheelchair users
also rely on their arms exclusively for other daily activities such as transfers and weight
shifts, they are at risk for developing shoulder pain and repetitive strain injuries due to
overuse. Individuals with higher levels of SCI use their shoulder muscles more to
compensate for poor trunk stability during propulsion. As a result, individuals with higher
levels of SCI are at greater risk for developing shoulder pain and rotator cuff–related
injuries. (42)
A program with electrical stimulation conditions and prepares the trunk muscles for the
required task of wheelchair propulsion. (43) The study by Koontz et al (43) concluded
that functional electrical stimulation on the trunk musculature has potential advantages in
helping manual wheelchair users with spinal cord injury improve propulsion efficiency
without placing additional demands on shoulder musculature.
Patients with tetraplegia often have respiratory complications because of paralysis of the
abdominal and intercostal muscles. The abdominal muscles are powerful muscles for
expiration, playing an important role in functions such as forced expiration
and coughing (44). The reduction in cough peak flow affects the ability to clear the
airways leading to an increased likelihood of respiratory infections in individuals with
chronic tetraplegia.
In fact, respiratory problems are a major cause of morbidity and mortality in both acute
and chronic cervical SCI, for example,pneumonia resulting from infection of retained
secretions. Even though patients with low cervical and high thoracic injuries to the spinal
cord can breathe independently because of intact diaphragmatic function, they too have
a significantly reduced vital capacity, tidal volume and cough peak flow because of
paralysis of the intercostal and abdominal muscles. (45)
A study by Gollee et al (46) shows that FES using surface electrodes placed on the
abdominal wall can significantly improve tidal volume and cough peak flow and
significantly improve respiratory function in tetraplegic subjects. Furthermore assisting
the patients to cough helps to clear bronchial secretions more effectively and in the long
run could help prevent respiratory infections.
In conclusion, the lack of voluntary control of the trunk muscles can have serious
functional and health-related implications particularly for high level SCI.
FES Therapy – A logical solution
The RT300 is a system which integrates FES with a motorized leg and arm ergometer to
deliver a complex, non volitional therapy.
Able bodied individuals have many physical activity choices in which they can partake
with or without the use of any equipment. Indeed, because an able bodied person has
an undamaged nervous system they routinely achieve a threshold of activity and
relatively good health just from undertaking their activities of daily living. This level of
normal activity, even without any additional exercise, is far beyond what can be
achieved by any means apart from FES ergometry.
The RT300 system provides a therapeutic intervention that applies patterned electrical
activation of the nervous system below the patient’s level of injury. This is not a volitional
activity selected from a wide range of available choices. This is not an optional activity
for paralysed clients using passive motion. Profound immobilty following spinal cord
injury is a unique situation requiring special solutions. FES cycle ergometry is the only
way that a paralysed individual can restore a threshold level of activity beneath his level
of injury.
1. Efficacy and cost comparisons
The safety, efficacy and economy of the RT300 cycle ergometer are superior to
conventional therapies such as passive movement. Passive therapy is when the arms
and legs are moved mechanically by a therapist’s hands or a machine - such as a less
expensive passive cycle. For an individual with a neurologic injury, passive therapy does
not create muscle contractions and does not deliver any of the benefits of FES cycling
as described earlier. The RT300 cycle ergometer allows a patient to perform active
therapy. Active therapy is when a patient’s muscles are doing the work and completing
movements under their own control or activated by FES.
Patients with a neurologic injury and disability are at increased risk for cardiovascular
disease-related secondary complications, such as pressure ulcers and attenuated
wound healing. Research has shown that passive cycling does not alter arterial leg
blood flow in patients with SCI and the results do not support the use of passive
movement or passive exercise for the prevention of cardiovascular-related secondary
complications. (39)
Background to the RT300 FES system
Functional Electrical Stimulation (FES) cycling therapy has a long history of clinical and
at-home use. FES cycling was first cleared by the FDA in the United States over 25
years ago with specific indications for the management and treatment of neurological
injury or impairment. Therefore, an FES cycle, such as the RT300, is not a new piece of
durable medical equipment. It is equipment with an established record as a primary athome intervention for people with neurological impairment or disability.
The RT300 provides intense electrical stimulation (currents up to 140mA) to peripheral
nerves below the level of a patient’s neurologic injury. This level of electrical stimulation
is the amount of current required to evoke muscle contractions in a neurologically
impaired person and is far beyond the level, which could be tolerated by a person
without a neurologic disease or disability.
The RT300 FES system has been FDA cleared for prescription use in persons with
spinal cord injury.The FDA approved indications for this system include:
1.
2.
3.
4.
Relaxation of muscle spasms
Prevention or retardation of disuse atrophy of lower extremity musculature
Increasing local blood circulation
Maintaining or increasing range of motion
Suitable for Home Setting
In the home environment, the RT300 is linked via the Internet to the manufacturer’s
(Restorative Therapies Inc.) secure database, RTILink. Each time a patient completes a
therapy session, the performance data is downloaded to the database. Results from the
data (over 1.5 million miles of cycling from over 7,000 patients and 250,000 therapy
sessions) show that FES cycling routinely improves strength and endurance. There is an
average compliance of 2-3 sessions per week. Clinicians monitor and control patient use
of the cycle ergometer outside of the research and clinical setting – providing on demand
at-home supervision to ensure patient safety, effectiveness and compliance.
Patients receive weekly graphs by email showing their cumulative distance and energy
expended to help keep them motivated. They can also compare their performances to
others with the same condition.
Standard of Care
FES has been used for many years in the UK and Eire Spinal Rehab Centres.
Initially FES was used to stimulate only muscles that moved volitionally. FES cycling is
now used to strengthen muscles whether they respond volitionally or not. The gains in
health and healthcare cost reductions benefit all stakeholders.
The RT300 cycle is currently utilized in the following UK and Eire spinal rehabilitation
facilities:
Stoke Mandeville
Sheffield
Stanmore
Middlesbrough
Southport
Cardiff
Glasgow
Belfast
Dublin
It is also utilized in the leading spinal cord injury centres in the U.S, Europe and
Australia.
Conclusion
Over 30% of all spinal cord injured patients are hospitalized annually. For this patient
population, the RT300 represents a lifelong commitment to protecting their health,
improving their quality of life and avoiding expensive and debilitating secondary
complications. These secondary complications typically include pressure sores,
diabetes, osteopenia with risk of fractures, blood lipid and testosterone disorders,
recurrent urinary tract infections, spasticity, joint stiffness and early cardiovascular
disease. All of these secondary complications arise due to preventable chronic
immobility which in turn results in insufficient disease management post neurologic
injury; and all are well documented in the SCI literature.
They also reduce the quality of life for these patients and result in escalating healthcare
expenses. These expenses can far exceed the cost of an RT300 FES Cycle..
The cycle specifically alleviates his spasms which interfere with activities of daily living
and which require pain and spasm reducing medication. The cycle can help build
muscle bulk to improve seating position and posture due to non-anterior
pelvis which exposes the coccyx area to skin breakdown and potential flap surgery. The
cycle can help strengthen weak trunk muscles improving posture and mitigating
respiratory complications; the most common cause of morbidity and mortality in both
acute and chronic cervical SCI.
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