The ability to walk is often one of the major long-term goals of spinal cord injury (SCI) patients. Studies have demonstrated that in terms of recovery in patients with some preserved walking functions, improving the quality of walking ability ranks higher than bladder, bowel and sexual functions.1 In addition, individuals with incomplete injuries more often than not are able to regain some capacity to walk; 86% of these patients ultimately will develop some degree of walking ability.2 Thus, exploring paths to a “walking recovery” is one critical aspect of rehabilitation in cases of incomplete paraplegia.
Achieving a walking recovery in SCI patients is not a simple process and presents challenges at a number of places and processes. Walking disorders manifest in multiple ways including varying degrees of reduced walking speeds, longer walking cycles, shorter stride distances and “angular displacements of lower limb joints”.3 There are a number of sensory cues that also affect walking in SCI patients.
... a key aspect of the recovery process for every patient is the selection of appropriate interventions and their integration into a comprehensive rehabilitation program.
These include stepping velocities, sustainable loads on the limbs; inter-limb coordination; hip, knee and ankle kinematics; and maintaining an upright torso and head position.4 Other factors that are relevant to walking after SCI include:
- Hyperactive spinal reflexes (spasticity)
- Alterations in muscle activation patterns (weakness and lack of motor coordination)
- Postural problems (weight bearing, balance and propulsion)5
Additionally, since a complete recovery of walking cannot be achieved in every case, for patients with incomplete SCI and some ability to walk, there is often an increased risk for falling.6
Rehabilitative interventions aim to contribute to the recovery of walking in patients with incomplete SCIs and reduce the risk for falls, which are associated with an increased likelihood of fractures. In striving for this goal, a key aspect of the recovery process for every patient is the selection of appropriate interventions and their integration into a comprehensive rehabilitation program. From a health professional’s perspective, this requires knowledge about the physiology of walking and specific pathological mechanisms of walking with an SCI.
Evidence from clinical research often impacts the types of interventions undertaken. A recent study focused on the walking development of babies compared to that of SCI patients. Both groups have weak descending input from the brain and results showed that supraspinal input is important in the control of walking on level ground.7
There has also been promising evidence that locomotion can be generated based on spinal cord circuits (see Box 1), offering opportunities for improved walking for SCI patients.8
In essence, a walking recovery depends upon a patient “learning new motor strategies to replace lost functions”; these new strategies reproduce motor equivalents that allow for normal foot motions.9
Studies of SCI in animal models have shown that body weight supported treadmill training results in muscle activities similar to those observed in normal animals, implying the reactivation of neuronal circuits both in the brain and the spine.10 This has yet to be conclusively shown, however, in humans. Nevertheless, rehabilitation focused on walking following an incomplete SCI will necessarily involve interventions to improve these neuronal circuits.11
Box 1 | The Biomechanics and Physiology of Normal Walking
Bipedal walking is a complex and practiced activity considered both automatic and controlled. It comprises a series of movements involving multiple body systems and parts. Recent studies, known as gait analyses, have attempted to describe locomotion by elaborating some of the complicated processes and concepts involved, including kinematics, indirect measures of muscle force, temporal-spatial parameters and joint angles. An explanation of these concepts is beyond the scope of this case study.
However, three key prerequisites of walking can be described. These include:
- movement synergy for propulsion,
- equilibrium maintenance during the movement
- and the "adaptation of locomotor pattern to the behavioural goals of the person and the constraints of the environment".
In addition, motor centers in the brain function to integrate various sensory information such as related to visual, vestibular and proprioceptive functions, as well as the cognition necessary to refine movements and for behaviour selection.
In animal studies, the control of walking involves interactions between collected sensory information with what are called central pattern generators in the spinal cord. Neurologically, efferent information from the lower extremities is processed by the interneurons in the spinal cord, which in turn interact with supraspinal connections in the brain. This neuronal activity generates flexion and extension in the muscles of the lower limbs. Physically, a normal walking cycle involves the repetition of two phases rarely considered in everyday life: the stance phase and the swing phase. Basically, during the stance phase the foot in front contacts or "strikes" the ground, at which the weight is borne by this single limb. The other foot then moves forward, striking the ground and beginning the swing phase. In the swing phase, the other foot again swings forward returning to the forward position and again striking the ground. This cycle repeats itself again and again.
Identifying normal and abnormal patterns of walking using gait analysis is the first step toward finding ways to address problems in walking.
Identifying intervention targets – a refined process.
Selecting appropriate interventions is one of the critical skills required of rehabilitation practitioners in rehabilitation management. Once a patient’s rehabilitation goals have been defined, achievement greatly depends upon the next stage of a patient’s assessment: identifying intervention targets.
Health professionals must identify the causal relationships between each rehabilitation goal and a given patient’s modifiable intervention targets, selecting those that will best contribute to attaining the goals set. Each of a patient’s targets should be directly related to the hierarchy of goals in a given Rehab Cycle.
Intervention targets are commonly defined and described utilizing the terminology of the WHO’s ICF in the components of body functions, body structures, activities and contextual factors. This helps to facilitate communication and promote a common understanding of rehabilitation goals, processes and elements across different professions.
Even though the integration of information into planning rehabilitation is often not an exact science, a healthcare provider’s decision-making process based on clinical reasoning and evidence-based practice offers the best path for determining the most appropriate interventions; the process might even be referred to as the “art of rehabilitation” (Box 2).
As a result, healthcare providers must integrate and utilize the best available external evidence with their own knowledge, training and experience in making an informed decision when selecting interventions. Ideally, such an approach is integrated into the assessment, assignment and intervention steps of the Rehab Cycle where goals and interventions are defined.
Box 2 | Clinical Reasoning and Evidence-based Rehabilitation
Simply defined, clinical reasoning is the "thinking and decision-making processes that are used in clinical practice"; more precisely, it is a process where a health professional interacts "with the patient and others (such as family members or others providing care), helps patients structure meaning, goals and health management strategies based on clinical data, patient choices, and professional judgment and knowledge".
In determining interventions and their targets, healthcare providers must utilize and integrate a variety of data, skills and strategies. In an approach based in clinical reasoning, bio-psycho-social knowledge must meet diagnostic, narrative, collaborative and prognostic skills, along with an ability to communicate and recognize clinical cues, patterns and relationships. During this process a patient's specific needs and care context are also important to consider. Once integrated, all of this information together provides a clear understanding of the patient and his or her problems. Useful for facilitating clinical reasoning, the Rehab-Cycle® and the ICF framework can be employed to emphasize associations extracted from available information as well as in promoting a flexible, interdisciplinary and patient-focused approach.
Another closely related therapeutic approach that helps healthcare providers determine suitable and effective targets and interventions is known as evidenced-based practice. This approach has been defined as "the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients". Thus, the results of quality clinical research can help inform decisions made by healthcare providers, sometimes providing the optimal path to achieving a patient's goals. However, this evidence-based approach is not always straightforward. For example, the Cochrane Organization, an international, independent and not-for-profit institution that conducts systematic reviews about the effectiveness of healthcare including interventions, reviewed four studies involving 222 patients that examined different locomotor trainings aimed at improving walking ability in SCI patients. The results of this meta-analysis were inconclusive illustrating the difficulty of determining which interventions are best for a specific problem:
Many strategies exist to improve [locomotor] function, such as treadmill training with and without body weight support, robotic-assisted gait training and functional electrical stimulation...There is insufficient evidence to conclude that any one approach to locomotor training strategy improves walking function more than another for people with SCI.
Mehrholz J, Kugler J, Pohl M - The Cochrane Collaboration
This case study offers the example of one incomplete SCI patient’s recovery of walking ability. The study aims to illustrate the importance of identifying intervention targets and appropriate interventions based on goals for successful rehabilitation. It will also highlight the utility of clinical reasoning and an evidenced-based approach.