FES and AFOs for Foot Drop: Linking Domains of Patient Experience
February 2021 Issue
It's natural to think in structural terms when considering the value of the treatment we provide, because O&P care is so closely identified with the provision of a device. Individuals are referred to us following impairments in body structure and function, including missing, misaligned, or malfunctioning body segments resulting from trauma, loss of neurological or motor control, or other pathologies. We evaluate biomechanical needs and recommend a specific design that provides structural solutions to the problems we determine to be most limiting. Practitioners also recognize that structural problems and solutions have functional consequences, and that functional capacity impacts participation in activities necessary for maintaining independence in life and the enjoyment of it. All the links in this chain of the patient's experience must be considered when making clinical recommendations.
For example, appropriate structural support of a weak lower limb may improve gait speed and quality, which has been correlated with an increase in patient quality of life (QOL). Diminished use or outright abandonment of a device limits these long-term beneficial effects and can ultimately reduce QOL. The goal of the treatment team should be to recommend interventions that achieve structural and functional goals, are satisfactory to the patient, and improve the patient's QOL. Practitioners are faced with the challenge of considering these various aspects of each patient's condition and experience and determining the most appropriate structural intervention to achieve the desired biomechanical and personal outcomes.
Foot drop is often treated with a structural intervention (an AFO) to maintain a dorsiflexed ankle position during swing phase. Functional electrical stimulation (FES) provides a different solution by restoring physiological dorsiflexion. Both interventions have the immediate effect of preventing foot drop by preventing or limiting plantarflexion during swing phase, and also result in longer term positive effects related to their ongoing use. As gait improves using either intervention, patients may experience other benefits that improve function and QOL. Research is often focused on only one aspect of the patient experience, but several studies have compared the effects of these two interventions on function and QOL factors. Evaluating this research can provide insights into the patient experience and guide practitioners in making clinical recommendations to address this and other impairments addressed by O&P interventions.
RCTs Comparing AFOs and FES
In 2013, Kluding et al. published the results of the Functional Ambulation: Standard Treatment versus Electric Stimulation Therapy (FASTEST) study. The randomized, single-blinded, 30-week trial compared the Bioness NESS L300 foot drop stimulators (FDS) and AFOs to treat post-stroke foot drop and involved 197 participants at 11 different sites.1 While gait speed improved significantly when using either device, "no significant differences in gait speed were found in the between-group comparisons. Secondary outcomes (standard measures of body structure and function, activity, and participation) improved significantly in both groups, whereas user satisfaction was significantly higher in the FDS group than in the control [AFO] group."1
In 2014, Bethoux et al. published the results of a randomized controlled trial involving 399 participants at 30 sites in the United States that was designed "to compare changes in gait and quality of life (QOL) between FES and an AFO in individuals with foot drop poststroke."2 The FES system used in this study was the WalkAide, and the initial study followed participants for six months. A wide variety of outcome measures were used to assess the function, satisfaction, and QOL of participants. The researchers found that "FES proved noninferior to the AFO for all primary endpoints," and concluded that the "use of FES is equivalent to the AFO."2 Another report by the same researchers on the same group of subjects reported that the 12-month results demonstrated that results for the two interventions were essentially the same.3 Bethoux et al. found "no significant between-group differences" for the Stroke Impact Scale (measuring participation) and the Stroke-Specific Quality of Life outcome.2 However, Kluding et al. found that "the total user satisfaction survey score measured at week 12…was significantly higher" among the FES group than the AFO group.1 The results for some of the measures are summarized in Table 1. A 2016 meta-analysis comparing how FES and AFO use affect walking reported "comparable improvements in walking speed…, functional exercise capacity…, timed up-and-go…, and perceived mobility…for both interventions."4 Considered together, the results of these studies demonstrate the importance of considering individual cases when making treatment recommendations. Since there is no clear benefit to one intervention over the other, clinicians must determine which factors are most important to each patient.
Short- and Long-term Effects
We can usually observe immediate effects of any intervention we provide, and also recognize that continued use and proficiency can have additional positive effects. Clinicians should keep these different effects in mind when assessing treatment efficacy and value. We tend to evaluate how an orthosis or prosthesis fits when it is delivered and rely primarily on general reports from referral sources and patients during follow-up appointments to determine how much the patient is using the device and the benefits derived from that use. It is helpful to remember that the improvements in function caused by appropriate structural support can create additional benefits.
It's appropriate to remind clinicians to focus less on the drill and "sell the hole in the wall." We should also remember that holes are drilled in walls for specific purposes, such as bringing light into a darkened space. Focusing on short- and long-term QOL benefits of treatment may be analogous to selling the light that dispels the darkness experienced by loss of function. The impact of an AFO or FES system on toe clearance is usually immediately obvious. How the patient benefits long term from that improved gait pattern should also be assessed and documented.
Use of consistent terminology and categorization of the different effects of an intervention can help us demonstrate the value of treatment. Kottnik described the orthotic effect of FES as "the effect that occurs during stimulation" and "the therapeutic (carry-over) effect" as "the effect that remains even after the stimulator has been removed.5 Kluding's clarification of three types of effects of a foot drop device are summarized in Table 2.
Adherence and Adverse Effects
Rates of adherence in the initial Bethoux study demonstrate some of the challenges related to long-term device use. Twenty-five of the 242 subjects in the WalkAide group and 13 of the 253 subjects assigned to the AFO group exited the study due to noncompliance with the study protocol.2 An additional seven subjects exited the WalkAide group and ten exited the AFO group due to dissatisfaction with the device.2 Patients may find a particular intervention more or less difficult to manage, depending on many different factors, and this can impact use and outcomes more than the immediate structural and functional benefit of the intervention. Adverse effects, ranging from minor irritations to more serious events such as falls, will also impact patient use and satisfaction. Because it is difficult to predict which issues will become problematic for each patient, transparency about common challenges and potential negative outcomes is an important part of the shared decision-making process. "Selling" the hole and the light it lets in includes an honest description of the difficulties associated with using a device. Adherence is more likely if patients are given an accurate description of the challenges they will face and suggestions about how to overcome them, and not just the benefits commonly experienced. Authentic shared decision-making requires realistic descriptions of the benefits and challenges of treatment options.
A wide range of outcome measurement tools are available to assess important factors related to the effects of different interventions. Outcomes should be measured in a variety of domains (such as function, satisfaction, QOL, and participation) at the initial assessment and periodically throughout the rehabilitation process. Measuring these aspects of the patient experience will help to make the relationship between the links in the chain of patient experience explicit. We may know intuitively that improvements in specific gait characteristics result in improved function and satisfaction, but measuring each of those domains can help us make that case more credibly. This information can be used to justify treatment options to referral sources, patients, and third-party payers. Since many of these outcome instruments are not commonly used in O&P practice, an investment may be required to become familiar with different options. Credible outcomes can be reported when correctly using instruments that are validated for specific patient populations.
Clinical decision-making is complex and multifactorial. When making recommendations, practitioners need to consider the variety of ways in which the interventions we provide impact the patient. Assessing structural, functional, and QOL outcomes requires an awareness of how each of these factors can impact a particular patient. Perhaps someday it will be as common for practitioners to regularly assess the psychosocial outcomes of our treatment as it is to measure physical outcomes. Until then, improving our awareness of the variety of ways our patient's experience the effects of our treatment can help us be sensitive to their individual needs and meet them more effectively. O&P EDGE
John T. Brinkmann, MA, CPO/L, FAAOP(D), is an assistant professor at Northwestern University Prosthetics-Orthotics Center (NUPOC). He has over 30 years of experience in patient care and education.
Daniel Weiser, MPO, is a 2020 graduate of NUPOC and an O&P resident at Dankmeyer, Linthicum Heights, Maryland.
Kluding, P. M., K. Dunning, and M. W. O'Dell et al. 2013. Foot drop stimulation versus ankle foot orthosis after stroke: 30-week outcomes. Stroke 44(6):1660-9.
Bethoux, F., H. L. Rogers, and K. J. Nolan et al. 2014. The effects of peroneal nerve functional electrical stimulation versus ankle-foot orthosis in patients with chronic stroke: A randomized controlled trial. Neurorehabilitation and Neural Repair 28(7):688-97.
Bethoux, F., H. L. Rogers, and K. J. Nolan et al. 2015. Long-term follow-up to a randomized controlled trial comparing peroneal nerve functional electrical stimulation to an ankle foot orthosis for patients with chronic stroke. Neurorehabilitation and Neural Repair 29(10):911-22.
Prenton, S., K. L. Hollands, and L. P. Kenney. 2016. Functional electrical stimulation versus ankle foot orthoses for foot-drop: A meta-analysis of orthotic effects. Journal of Rehabilitation Medicine 48(8):646-56.
Kottink, A. I., L. J. Oostendorp, and J. H. Buurke et al. 2004. The orthotic effect of functional electrical stimulation on the improvement of walking in stroke patients with a dropped foot: a systematic review. Artificial Organs 28(6):577-86.