Robotic Gait Training in Spinal Cord Injury

INTRODUCTION:

The ability to move and transfer own body in an effective manner, is frequently affected in people with a spinal cord injury with a negative impact in mood and quality of life, in such a way, that achieving an effective locomotion, is one of the main objectives in the rehabilitation program in a spinal cord injured patient.

There are different modalities of locomotion training in spinal cord injury, being the robotic orthosis among them, and offering until now, positive outcomes. However there´s still a lack of evidence of the optimal training characteristics, in order to establish the best time, number of sessions, and progression scheme. For these reasons, establishing the effects of different locomotion training programs will provide the necessary data in order to develop an effective training program for the maximum benefit of the patient.

OBJECTIVE To determine the effect of different training programs with robotic gait orthosis for patients with chronic motor incomplete spinal cord injury (SCI) (American Spinal Injury Association Impairment Scale (AIS) C / D) in short and long term.

METHODS AND DESIGN. The design of the study consists on a randomized, blinded to the observer, clinical trial.

Patients from the National Institute of Rehabilitation (INR) with spinal cord injury, AIS C and D, with at least 6 months of evolution, and who are able to walk with or without gait auxiliary, will be eligible.

Informed consent will be obtained from all subjects prior to participation. Patients will be randomly assigned to either one of the two different training groups: intervention or control group.

The control group will be submitted to training sessions of 30 minutes, and the intervention group will have training sessions of 60 minutes.

Both groups will receive a training period of six weeks, five days a week.

Throughout the training period, gait assessments with the GaitRite instrument, will be performed, and repeated at 6 and 12 months after completion of the training as part of follow up. The data obtained from the GaitRite will be compared within each group, in order to determine which type of training is more effective

Statistical analysis will be performed using SPSS, considering all P \< 0.05 as statistically significant.

A Spinal cord injury (SCI) is the disruption of the nerve pathways that connect the brain to the rest of the body, causing the cessation of their motor, sensory and vegetative functions. It is considered one of the most devastating clinical conditions affecting the functionality and independence of the individual.

The World Health Organization estimates an annual overall incidence of 40-80 new cases per million, equivalent to 250 000 to 500 000 individuals with spinal cord injury each year. The consequences of the SCI, significantly impair the ability of the patient to perform daily life activities, and their overall quality of life.Decreased mobility is the main element that affects lower satisfaction and quality of life. The improvement of mobility or the ability to move in an energy efficient manner improves the quality of life in patients with SCI.

The recovery of walking function is considered of great relevance both by patients and physicians. The most relevant prognostic factor for functional recovery in SCI patients is the neurological status at the moment of the first examination, considering the neurological level and the severity of the lesion according to the American Spinal Injury Association impairment scale (AIS).

According to Scivoletto, of the patients with American Spinal Injury Association (ASIA) impairment scale A, with thoracic and lumbar lesion only 6.4% achieve functional walking. In patients with ASIA B, have an overall rate of ambulation of 23.5%, ASIA C have 51.4% and ASIA D patients have a prognosis for walking recovery between 80-100% (88.9%).

In another study, Dobkin\[8\] reported that 35% of individuals classified as AIS B, 92% of subjects AIS C and all subjects AIS D recovered the ability to walk after gait training intervention with partial weight bearing for a period of 8 weeks. However, of all the patients with spinal cord injury, few regain a functional gait capacity, due to a low speed, a decreased step length, cadence and changes in rhythm and coordination.

In fact, spinal cord injury often leads to changes in walking patterns, which are associated with postural changes related to poor ability to transfer bodyweight, alterations in balance and equilibrium. Other important factors in the process of walking recovery include: lack of coordination and development of propulsion, sensory loss, and hyperactive spinal reflexes. These deficiencies are severe enough to delay standing and gait rehabilitation process .

Some of the most important gait abnormalities in individuals who suffer spinal cord injuries are: the inability to stand without assistance, the voluntary movement of joints such as hip hip, knee and ankle, knee hyperextension, inability to move the legs without making compensation mechanisms, foot dragging, changes in weight transfer during walking, lack of coordination, transition among phases of gait, and falls.

That is the reason why many gait training programs have been evaluated. Current modalities of gait training, pretend to activate the locomotor center of the central pattern generator by repetitive gait stimuli, allowing the central nervous system plasticity to create new neural pathways and connections in the spinal cord, making possible walking recovery in patients with spinal cord injury. Evidence favors two gait training modalities: the treadmill with partial weight-support and the robotic-assisted gait. These training modalities provide an improvement in gait parameters and functionality when compared to conventional physiotherapy, as shown in the systematic review by Morawietz and Moffat in which different programs of gait training in patients with SCI AIS C and D of diverse etiology of chronic and acute evolution and any neurological level are compared.

Although the use of treadmill , partial weight-bearing and robotic orthotics are essential in the training of locomotion in SCI patients , little has been published about the progress of the training, clinical decision making and evaluation of progress.\[16\] Most of the studies on the subject provide only very general criteria to optimize treatment (modifying body weight support and speed training), providing insufficient evidence to guide the training progression in parameters such as training frequency, speed and optimal duration of treatment.

As a result, it is important to develop studies which test training strategies that help to clarify issues related to the amount, intensity, frequency, and progression of training in order to achieve the maximum recovery of gait for individuals with SCI. Accordingly, to determine and compare the effect of different gait training programs will orient the development of more effective training programs.

OBJECTIVE

To determine the effects on gait of different gait training programs using a robotic gait orthosis in individuals with chronic incomplete SCI (AIS C/D).

Specific Objectives

1. To evaluate changes in functionality of gait and spatiotemporal gait parameters, functional independence, lower limbs muscle force, spasticity and joint range of motion of individuals according to different progression programs.
2. To determine in the short term (immediately posterior to training program), medium term (6 months) and long term (1 year) effect on individuals' functionality of gait, spatiotemporal gait parameters and functional independence obtained with different gait training programs.
3. To compare the effect of the two different programs of gait training using a robotic gait orthosis.

METHODS

7.1.- Study Design: Randomized Clinical Trial blinded to observer.

7.2.- Subjects: Subjects from inpatient and outpatient services within the Neurologic Rehabilitation Department of the National Institute of Rehabilitation with SCI AIS C and D, with at least 6 months since injury and able to walk with or without walking aids.

Sample Size

Sample Size was calculated based on improvement on gait velocity reported by previous published studies using the program Epidat 4.

It was calculated that 23 patients are required in order to detect a difference between means of 32.3 cm/s, as reported by Wirz , with a standard deviation of 37.5 cm/s, a power of 80% and a confidence level of 95% On the other hand, Hornby reported a difference between means of 0.36 m/s with a standard deviation of 0.14 m/s, which results on a sample size of 4 subjects per group.

Due these differences, an initial trail will performed with an initial sample size of 4 subjects per group and a new calculation of power of the study will be made in order to determine convenience of sample size or necessity of a bigger sample.

RANDOMIZATION The randomization will be conducted by a digital randomization system with atmospheric noise, available at random.org. Allocation will be done by a person not included in the protocol.

Proceeding

The outpatients that assist to the Spinal Cord Injury Service at the "Instituto Nacional de Rehabilitación" will be randomly assigned to two different groups.. The groups are defined as follow:

A. Control group, with 30 training sessions in robotic orthosis with duration of 30 minutes during 6 weeks.

B. Control group, with 30 training sessions in robotic orthosis with duration of 60 minutes during 6 weeks.

Proposed statistical analysis

Descriptive statistics will be carried out with measures of central tendency for quantitative variables and proportions for qualitative variables. In order to analyze differences between groups, co variance analysis will be conducted. We will consider results as statistically significative when p\<0.05.

Eligibility Criteria:
Inclusion Criteria:

* Incomplete SCI AIS C or D with at least 6 months of evolution.
* Any etiology
* Able to walk with or without walking aids.
* Properly signed written informed consent.

Exclusion Criteria:

* Orthopedic conditions like bone instability , arthrodesis
* Metabolic pathology which impedes exercise.
* Audio or visual alterations.
* Own Robotic Orthoses (lokomat) counter-indications: body weight bigger than 135 kg, open lesions in skin of lower extremities or torso, non-cooperative patients, mechanical ventilation or continuum use of oxygen.
* Uncontrolled pain.