Jennifer Unterreiner MS, DPTc PT 209-910 May 5, 2012
Spinal cord injury (SCI) results in permanent disability, and loss of movement or sensation below the site of injury (Mayo Clinic, 2011) Loss of movement or sensation below the level of injury greatly impacts a patients function and independence (Umphred, 2007, O Sullivan and Schmidt, 2000)
Approximately 12,000 new cases of spinal cord injury per year Mean age of injury approximately 40.2 years National SCI Statistical Center 6/09
PTs are faced with the challenge of how to treat these patients These patients do not respond to typical strengthening protocols utilized by PTs Histological changes occur after SCI that result in increased fatigability and decreased endurance of the muscles (Newham et al., 2007)
Lesion to the spinal cord that results in paralysis, decreased sensation, bowel/ bladder dysfunction and hyperreflexia Two types of SCI: complete and incomplete Affects a variety of the body systems depending on level of injury Umphred, 2007, O Sullivan and Schmidt, 2000
Utilizes functional electrical stimulation to bilateral quadriceps, gluteals, and hamstrings Stimulates peripheral nerves to evoke patterned movement Provides assistance or resistance Hypothesized to improve muscular strength and endurance http://2.bp.blogspot.com Hamzaid et al., 2009, Wilder et al., 2002
3 types of motor units: Slow Fast/Fatigue Resistant Fast/Fatigable 3 types of muscle fibers: Slow Type I Fast Type IIA Fast Type IIX Caiozzo, V., 2011, Lee, M. 2009
Type I fibers are slow oxidative fibers Low force production and fatigability Type IIA fibers are fast, oxidative and glycolytic fibers Intermediate force production and fatigability Fast relaxation times Type IIX are fast glycolytic fibers High force production and fatigability Fast relaxation times Caiozzo, V., 2011, Lee, M. 2009
SCI patients have an increase in fast twitch fibers, Type II, within a few months of injury Increase in Type II fibers leads to increased fatigability in muscles Changes may be associated with decreased endurance, muscle atrophy and increased muscle fatigue Gerrits, HL. et al., 2002, Chilibeck, PD., et al., 1999
Power Output (PO): amount of force produced Relaxation time: amount of time it takes for the excited muscle to return to its baseline level after a contraction Fiber area: Cross-sectional area representing the size of the muscle fibers Percent of Type II fibers: ratio of the fiber composition of a given muscle
SCI patients have decreased strength below the level of the lesion Patients are unable to elicit strength changes through standard protocols These patients require an intervention that bypasses the lack of response The FES bike has been hypothesized to produce physiological and physical changes including muscular strength and endurance (Newham et al., 2007)
Research regarding the FES bike has looked at a variety of outcome measures Lack of functional outcomes Currently there are mixed results regarding the use and effectiveness of the FES bike
To evaluate the effectiveness of the FES bike in improving power output and modifying muscle histology in patients with an SCI http://www.laesieworks.com/spinal/sciinfo01.html
P Patients post SCI I FES bike C No true comparison O Muscle function and histology This is a foreground/intervention question
Hypothesis 1 Null: FES bike has no effect on muscle function/ power output Alternative: FES bike has a positive effect on muscle function/ power output Hypothesis 2 Null: FES bike has no effect on histological muscle composition Alternative: FES bike has a positive effect on histological muscle composition
At least 5 level 2C or higher studies To reject both null hypotheses Accept both alternative hypotheses
Inclusion Criteria: English Patients post SCI at any level both complete and incomplete SCI patients who received FES to the lower extremities Published in the last 15 years Level of evidence 2C or higher Exclusion Criteria: Neurological diagnoses other than SCI Lower motor neuron injuries/ Cauda equina syndrome Classify subjects with a system other than ASIA Outcomes in muscles other than the quadriceps
Databases: PubMed PEDro CINAHL Search Terms: alone and in combination Spinal cord injury Functional electrical stimulation or FES Functional outcomes Histological changes Completed recursive search of articles Articles were reviewed by a secondary reviewer to confirm inclusion criteria
Mean and standard deviation from the individual studies for the individual outcomes Effect size and 95% CI for each study Q statistics for heterogeneity Determine use of random or fixed effects model Individual studies were weighted according to inverse variance Pooled effect size and 95% CI Jewell, 2008
Articles recovered from electronic/ recursive search: (n=371) Articles excluded due to irrelevance: (n=310) Articles retrieved for further review: (n=27) Articles selected for inclusion in evidence based review: (n=5) Duplicates removed: (n=34) Articles removed due to not meeting the inclusion criteria: (n=22) o All articles included are level 2B of evidence
Study Participants Intervention Conclusion Duffell et al. (2008) Eser et al. (2003) Mohr et al. (1997) Chillibeck et al. (1999) Gerrits et al. (2000) 11 subjects ASIA A All Paraplegics 19 subjects ASIA A All Paraplegics 10 subjects ASIA A Tetra- and Paraplegics 6 subjects ASIA B Tetra- and Paraplegics 7 subjects ASIA A and B Tetra- and Paraplegics 1 hour/day 5 days/week for 1 year 260 hours 30 min/day 336 days/week hours for 24 weeks 30 min/day 378 days/week hours for 1 year 30 min/day 312 days/week hours for 8 weeks 30 min/day 3 days/week 9 hours for 6 weeks quadriceps torque, power output and fatigue Increase power resistance, no change in contractile output speed power output, greater improvements at higher stimulation frequencies Increase fatigue resistance power output, muscle area, fatigue resistance, and oxygen uptake Increase fiber area power output, fiber area and capillary number Differing conclusions on fatigue resistance and power relaxation output, relaxation time time
Q statistic allowed for use of fixed effects model for all outcomes except power output Effect sizes: Minimal < 0.3 Moderate < 0.7 Large > 0.8 Jewell, 2008
0.38 (-0.32,1.08) Favors intervention
-0.15 (-0.85, 0.54) Favors intervention
-0.4 (-1.07, 0.26) Favors intervention
2.42 (1.24, 3.59) Favors intervention
3.64 (2.64, 4.65) Favors intervention
Not directly addressed Need to take into consideration signs and symptoms of autonomic dysreflexia and orthostatic hypotension Closely monitor the patients skin in order to prevent burns from the electrodes
PROS Potential to improve function and independence Act to counter some of the negative effects of immobility that occur as a result of SCI CONS Intense time commitment on the part of the patient and the PT Patient required to purchase their own unit Unit costs upwards of $13,000
No established minimal clinically important difference (MCID) for these outcomes Mild to moderate improvements in fiber area, Type II fibers and relaxation time Increase in Power Output by 20.86 W
H O1 : FES bike has no effect on muscle function/power output Able to reject null hypothesis FES bike leads to a significant improvement in power output, greater after 1 year Positive trend in data for relaxation time H O2 : FES bike has no effect on histological muscle composition Unable to reject null hypothesis FES bike does not result in significant improvements in fiber area or percent Type II fibers
Changes in power output suggest that there might be other changes occurring at the cellular and molecular level May help combat the co-morbidities that are associated with inactivity Pneumonia UTI s Pressure ulcers Depression Psychosocial issues Kennedy et al., 2011, Hoffman et al., 2011
Length of time required for patients to participate in the intervention may be difficult to reach in a typical clinical setting May be more feasible in a wellness type setting to improve patient access
Small number of studies included with small sample sizes Heterogeneity of subjects included in the studies Acute versus chronic Complete versus incomplete Tetra- versus Paraplegia Range in frequency and duration of the intervention across the studies
Repeating the included studies with larger sample sizes Completing studies with subjects who have similar demographics More consistent application of similar protocols to determine appropriate dosing Including functionally based outcomes
FES bike does produce power output changes in patients post SCI Unclear effect on histology and how use of the FES bike translates to functional improvements Use of the FES bike for longer periods of time may lead to greater improvements
Diane Allen, PT, DPT, PhD Andrew Lui, PT, DPT Jet Lee, PT, PhD Morgan Johnson, MS, DPTc Amanda Powell, MS, DPTc UCSF/SFSU DPT Class of 2012 Family and friends
1. Duffell, LD, Donaldson, N., Perkins, TA, Rushton, DN, Hunt, KJ, et al. Long- Term Intensive Electrically Stimulated Cycling by Spinal Cord-Injured People: Effect on Muscle Properties and Their Relation to Power Output. Muscle Nerve. 2008:38:1304-1311 2. Eser, P.C., Donaldson, N., Knecht, H., Stussi, E. Influence of Different Stimulation Frequencies on Power Output and Fatigue During FES-Cycling in Recently Injured SCI People. IEEE Trans Neural Syst Rehabil Eng. 2003:3:236-240 3. Mohr, T., Andersen, JL, Biering-Sorensen, F., Galbo, H., Bangsbo, J. et al. Long term adaptation to electrically induced cycle training in severe spinal cord injured individuals. Spinal Cord. 1997:35:1-16 4. Chilibeck, P.D., Jeon, J., Weiss, C., Bell, G., Burnham, R. Histochemical changes in muscle of individuals with spinal cord injury following functional electrical stimulated exercise training. Spinal Cord. 1999:37:264-268 5. Gerrits, H.L., de Haan, A., Sargeant, A.J., Dallmeijer, A., Hopman, MTE. Altered contractile properties of the quadriceps muscle in people with spinal cord injury following functional electrical stimulated cycle training. Spinal Cord. 2000:38:214-223
6. Mayo Clinic. Spinal Cord Injury. Available at: http://www.mayoclinic.com/health/spinal-cord-injury/ds00460. Accessibility verified January 2, 2012. 7. Atrice, MB., Morrison, SA., McDowell, SL., Ackerman, PM., Foy, TA. Traumatic Spinal Cord Injury. In: Umphred, DA. Neurological Rehabilitation. 5 th ed. St. Louis, MO: Mosby Elsevier; 2007: 605-657 8. Hamzaid, NA, Davis, GM. Health and fitness benefits of functional electrical stimulation- evoked leg exercise for spinal cord-injured individuals: A position review. Top Spinal Cord Inj Rehabil. 2009; 14: 88-121 9. Wilder, RP, Jones, EV, Wind, TC, Edlich, RF. Functional electrical stimulation cycle ergometer exercise for spinal cord injured patients. J Long Term Eff Med Implants. 2002; 12: 161-174 10. National SCI Statistical Center. Facts and Figures at a Glance. Available at: https://www.nscisc.uab.edu/. Accessibility verified January 2, 2012.
11. Kennedy, P., Phil, D., Lude, P., Elfstrom, ML., Smithson, EF. Psychological contributions to functional independence: A longitudinal investigation of spinal cord injury rehabilitation. Arch Phys Med Rehabil. 2011; 32: 597-601 12. Schmitz, TJ. Traumatic Spinal Cord Injury. In: O Sullivan, SB, Schmidt, TJ. Physical Rehabilitation: Assessment and Treatment. 4 th ed. Philadelphia, PA: F.A. Davis Company; 2000: 873-923 13. V. Caiozzo, Ph.D. The Cellular and Molecular Basis of Muscle Mechanics: Molecules to Motion. University of California, San Francisco. Physical Therapy 212: Muscle and Nerve Biology. September 2011 14. M. Lee, Ph.D. Skeletal Muscle Structure and Function. San Francisco State University. Kinesology 746: Exercise Physiology. June 2009 15. Jewell, DV. Guide to Evidence-Based Physical Therapy Practice. Sudbury, MA: Jones and Bartlett, 2008
16. Sheffler, LR., Chae, J. Neuromuscular electrical stimulation in neurorehabilitation. Muscle Nerve. 2007; 35: 562-590 17. Newham, DJ., Donaldson, N de N. FES cycling. Acta Neurochir Suppl. 2007: 97: 395-402 18. Smoot, B. PT, DPTSc. Designing Clinical Research Sampling: Who Will be Studied? University of California, San Francisco. Physical Therapy 251: Research Design. July 2010. 19. Hoffman, JM., Bombardier CH., Graves, DE., Kalpakjian, CZ., Krause, JS. A longitudinal study of depression from 1 to 5 years after spinal cord injury. Arch Phys Med Rehabil. 2011; 92: 411-8.