Thoracic-level Spinal Cord Injury Research Articles

Timing of tracheostomy in acute traumatic spinal cord injury: A systematic review and meta-analysis.

Patients with acute traumatic cervical or high thoracic level spinal cord injury (SCI) typically require mechanical ventilation (MV) during their acute admission. Placement of a tracheostomy is preferred when prolonged weaning from MV is anticipated. However, the optimal timing of tracheostomy placement in patients with acute traumatic SCI remains uncertain. We systematically reviewed the literature to determine the effects of early versus late tracheostomy or prolonged intubation in patients with acute traumatic SCI on important clinical outcomes. Six databases were searched from their inception to January 2020. Conference abstracts from relevant proceedings and the gray literature were searched to identify additional studies. Data were obtained by two independent reviewers to ensure accuracy and completeness. The quality of observational studies was evaluated using the Newcastle Ottawa Scale. Seventeen studies (2,804 patients) met selection criteria, 14 of which were published after 2009. Meta-analysis showed that early tracheostomy was not associated with decreased short-term mortality (risk ratio [RR], 0.84; 95% confidence interval [CI], 0.39-1.79; p = 0.65; n = 2,072), but was associated with a reduction in MV duration (mean difference [MD], 13.1 days; 95% CI, -6.70 to -21.11; p = 0.0002; n = 855), intensive care unit length of stay (MD, -10.20 days; 95% CI, -4.66 to -15.74; p = 0.0003; n = 855), and hospital length of stay (MD, -7.39 days; 95% CI, -3.74 to -11.03; p < 0.0001; n = 423). Early tracheostomy was also associated with a decreased incidence of ventilator-associated pneumonia and tracheostomy-related complications (RR, 0.86; 95% CI, 0.75-0.98; p = 0.02; n = 2,043 and RR, 0.64; 95% CI, 0.48-0.84; p = 0.001; n = 812 respectively). The majority of studies ranked as good methodologic quality on the Newcastle Ottawa Scale. Early tracheostomy in patients with acute traumatic SCI may reduce duration of mechanical entilation, length of intensive care unit stay, and length of hospital stay. Current studies highlight the lack of high-level evidence to guide the optimal timing of tracheostomy in acute traumatic SCI. Future research should seek to understand whether early tracheostomy improves patient comfort, decreases duration of sedation, and improves long-term outcomes. Systematic Review, level III.

Epidural Electrical Stimulation of the Lumbosacral Spinal Cord Improves Trunk Stability During Seated Reaching in Two Humans With Severe Thoracic Spinal Cord Injury

Background: Quality of life measurements indicate that independent performance of activities of daily living, such as reaching to manipulate objects, is a high priority of individuals living with motor impairments due to spinal cord injury (SCI). In a small number of research participants with SCI, electrical stimulation applied to the dorsal epidural surface of the spinal cord, termed epidural spinal electrical stimulation (ES), has been shown to improve motor functions, such as standing and stepping. However, the impact of ES on seated reaching performance, as well as the approach to identifying stimulation parameters that improve reaching ability, have yet to be described.Objective: Herein, we characterize the effects of ES on seated reaching performance in two participants with chronic, complete loss of motor and sensory functions below thoracic-level SCI. Additionally, we report the effects of delivering stimulation to discrete cathode/anode locations on a 16-contact electrode array spanning the lumbosacral spinal segments on reach distance while participants were seated on a mat and/or in their wheelchair.Methods: Two males with mid-thoracic SCI due to trauma, each of which occurred more than 3 years prior to study participation, were enrolled in a clinical trial at Mayo Clinic, Rochester, MN, USA. Reaching performance was assessed, with and without ES, at several time points throughout the study using the modified functional reach test (mFRT). Altogether, participant 1 performed 1,164 reach tests over 26-time points. Participant 2 performed 480 reach tests over 17-time points.Results: Median reach distances during ES were higher for both participants compared to without ES. Forward reach distances were greater than lateral reach distances in all environments, mat or wheelchair, for both participants. Stimulation delivered in the caudal region of the array resulted in improved forward reach distance compared to stimulation in the rostral region. For both participants, when stimulation was turned off, no significant changes in reach distance were observed throughout the study.Conclusion: ES enhanced seated reaching-performance of individuals with chronic SCI. Additionally, electrode configurations delivering stimulation in caudal regions of the lumbosacral spinal segments may improve reaching ability compared to rostral regions.

Imaging characteristics of chronic spinal cord injury identified during screening for a cell transplantation clinical trial.

OBJECTIVEIn cell transplantation trials for spinal cord injury (SCI), quantifiable imaging criteria that serve as inclusion criteria are important in trial design. The authors' institutional experience has demonstrated an overall high rate of screen failures. The authors examined the causes for trial exclusion in a phase I, open-lab clinical trial examining the role of autologous Schwann cell intramedullary transplantation. Specifically, they reviewed the imaging characteristics in people with chronic SCI that excluded applicants from the trial, as this was a common cause of screening failures in their study.METHODSThe authors reviewed MRI records from 152 people with chronic (> 1 year) SCI who volunteered for intralesional Schwann cell transplantation but were deemed ineligible by prospectively defined criteria. Rostral-caudal injury lesion length was measured along the long axis of the spinal cord in the sagittal plane on T2-weighted MRI. Other lesion characteristics, specifically those pertaining to lesion cavity structure resulting in trial exclusion, were recorded.RESULTSImaging records from 152 potential participants with chronic SCI were reviewed, 42 with thoracic-level SCI and 110 with cervical-level SCI. Twenty-three individuals (55%) with thoracic SCI and 70 (64%) with cervical SCI were not enrolled in the trial based on imaging characteristics. For potential participants with thoracic injuries who did not meet the screening criteria for enrollment, the average rostral-caudal sagittal lesion length was 50 mm (SD 41 mm). In applicants with cervical injuries who did not meet the screening criteria for enrollment, the average sagittal lesion length was 34 mm (SD 21 mm).CONCLUSIONSWhile screening people with SCI for participation in a cell transplantation clinical trial, lesion length or volume can exclude potential subjects who appear appropriate candidates based on neurological eligibility criteria. In planning future cell-based therapy trials, the limitations incurred by lesion size should be considered early due to the screening burden and impact on candidate selection.

Use of a dynamic gait trainer for a child with thoracic level spinal cord injury

Paediatric spinal cord injury (SCI) can result in permanent mobility impairment with consequences for activity, participation and quality of life. This case documents the effect of an overground supported stepping...

Control of standing balance at leaning postures with functional neuromuscular stimulation following spinal cord injury

This study systematically explored the potential of applying feedback control of functional neuromuscular stimulation (FNS) for stabilizing various erect and leaning standing postures after spinal cord injury (SCI). Perturbations ranging from 2 to 6% body weight were applied to two subjects with motor complete thoracic level SCI who were proficient at standing with implanted multichannel neural stimulators to activate the ankle, knee, hip and trunk muscles. The subjects stood with four different postures: erect, forward, forward-right and forward-left. Repeatable and controlled perturbations were applied in the forward, backward, rightward and leftward directions by linear actuators pulling on ropes attached to the subjects via a belt worn just above the waist. Upper extremity (UE) forces exerted on a stationary walker were measured with load cells attached to the handles. A feedback controller based on center of pressure (CoP) varied the stimulation levels to the otherwise paralyzed muscles so as to resist the effects of the perturbations. The effect of the feedback controller was compared to the case where only open-loop baseline stimulation was applied. This was done in terms of: (a) maximum resultant UE force exerted by the subjects on the walker, (b) maximum resultant CoP overshoot and (c) CoP root-mean-square deviation (RMSD). Feedback control resulted in significant reductions in the mean values of the majority of outcome values compared to baseline open-loop stimulation. Maximum resultant UE force was reduced by as much as 50% in one of the postures for one of the subjects. RMSD and maximum CoPs were reduced by as much as 75 and 70%, respectively, with feedback control. These results indicate that feedback control can be used to reject destabilizing disturbances in individuals with SCI using FNS not only for erect postures but also for leaning postures typically adopted during reaching while attempting various activities of daily living.

Effect of Orthotic Rehabilitation with Isocentric Reciprocating Gait Orthosis on Functional Ambulation in Patients with Spinal Cord Injury

ABSTRACT Objectives Functional ability defines a person's ability to walk, with or without the aid of appropriate assistive devices, safely and sufficiently to carry out mobility-related activities of daily living. Longitudinal evaluation of the efficiency of gait training positively affecting these parameters has not been reported. Therefore, the aim of this study is to provide evidence supporting the progression of walking speed and functional ambulation over 12 weeks of orthotic gait rehabilitation using an isocentric reciprocating gait orthosis (IRGO) in patients with spinal cord injury (SCI). Materials and Methods Twelve patients with SCI participated in this study. Gait evaluation was performed at baseline and at 4, 8, and 12 weeks following intervention with an IRGO and specific gait training. Gait speed and endurance were measured by the 10-m walk test and the 6-minute walk test, respectively. The Functional Independence Measure (FIM) locomotor subscale and the Walking Index for Spinal Cord Injury II (WISCI II) were used to measure the locomotor ability. Results Improvement in speed of walking was observed after 4 weeks and continued to improve with time. The distance of walking, FIM, and WISCI also increased significantly during the study period when compared with the baseline. Conclusion Patients with SCI showed an increase in walking functional ambulation ability during a longitudinal period of orthotic gait training with an IRGO. In conclusion, wearing IRGO associated with gait training can provide individuals with thoracic-level SCI the ability to walk faster.

Combining Adult Learning Theory with Occupational Therapy Intervention for Bladder and Bowel Management after Spinal Cord Injury: A Case Report

ABSTRACTBladder and bowel management is an important goal of rehabilitation for clients with spinal cord injury. Dependence is these areas have been linked to a variety of secondary complications, including decreased quality of life, urinary tract infections and pressure ulcers (Hammell, 2010; Hicken et al, 2001). Occupational therapists have been identified as important members of the health care team in spinal cord injury rehabilitation; however, specific roles and interventions have not been clearly described. This case report will describe occupational therapy interventions embedded with principles of adult learning theory to address bladder and bowel management with an adult client who sustained an incomplete thoracic level spinal cord injury.

Simulating the restoration of standing balance at leaning postures with functional neuromuscular stimulation following spinal cord injury.

In this simulation study, we present and examine methods to develop a feedback controller for a neuroprosthesis that restores forward and side leaning function during standing following complete thoracic-level spinal cord injury. Achieving leaning postures away from erect stance with functional neuromuscular stimulation (FNS) would allow users to extend their reaching capabilities. Utilizing a 3-D computer model of human stance, an FNS control system based on total-body center of mass (CoM) kinematics (position, acceleration) is developed and tested in simulation. CoM kinematics drive an artificial neural network to modulate muscle excitations and reduce the upper extremity loading, presumably against a walker or similar support surface, required to resist the effects of postural perturbations. Furthermore, a novel method to robustly estimate the feedback kinematics for standing applications is also presented while assuming 3-D accelerometer signals at locations consistent with a proposed implantable networked neuroprosthesis system. For shifting and balance at leaning postures, respectively, center of mass position and acceleration could be approximated to within 20% of the maximum value, with strong correlations (R > 0.9) between values estimated by the proposed method and the true values derived from model dynamics. When utilizing the estimated feedback kinematics for FNS control, standing performance in terms of maximum upper extremity loading was still significantly reduced (p < 0.001) compared to conventionally applying constant and maximal stimulation. In the future, these simulation-based methods will be employed to develop experimental approaches for restoring leaning standing function by FNS.

Finite state control of a variable impedance hybrid neuroprosthesis for locomotion after paralysis.

We have previously reported on a novel variable impedance knee mechanism (VIKM). The VIKM was designed as a component of a hybrid neuroprosthesis to regulate knee flexion. The hybrid neuroprosthesis is a device that uses a controllable brace to support the body against collapse while stimulation provides power for movement. The hybrid neuroprosthesis requires a control system to coordinate the actions of the VIKM with the stimulation system; the development and evaluation of such a controller is presented. Brace mounted sensors and a baseline open loop stimulation pattern are utilized as control signals to activate the VIKM during stance phase while simultaneously modulating muscle stimulation in an on-off fashion. The objective is twofold: reduce the amount of stimulation necessary for walking while simultaneously restoring more biologically correct knee motion during stance using the VIKM. Custom designed hardware and software components were developed for controller implementation. The VIKM hybrid neuroprosthesis (VIKM-HNP) was evaluated during walking in one participant with thoracic level spinal cord injury. In comparison to walking with functional neuromuscular stimulation alone, the VIKM-HNP restored near normal stance phase knee flexion during loading response and pre-swing phases while decreasing knee extensor stimulation by up to 40%.

The ReWalk Powered Exoskeleton to Restore Ambulatory Function to Individuals with Thoracic-Level Motor-Complete Spinal Cord Injury

The aim of this study was to assess the safety and performance of ReWalk in enabling people with paraplegia due to spinal cord injury to carry out routine ambulatory functions. This was an open, noncomparative, nonrandomized study of the safety and performance of the ReWalk powered exoskeleton. All 12 subjects have completed the active intervention; three remain in long-term follow-up. After training, all subjects were able to independently transfer and walk, without human assistance while using the ReWalk, for at least 50 to 100 m continuously, for a period of at least 5 to 10 mins continuously and with velocities ranging from 0.03 to 0.45 m/sec (mean, 0.25 m/sec). Excluding two subjects with considerably reduced walking abilities, average distances and velocities improved significantly. Some subjects reported improvements in pain, bowel and bladder function, and spasticity during the trial. All subjects had strong positive comments regarding the emotional/psychosocial benefits of the use of ReWalk. ReWalk holds considerable potential as a safe ambulatory powered orthosis for motor-complete thoracic-level spinal cord injury patients. Most subjects achieved a level of walking proficiency close to that needed for limited community ambulation. A high degree of performance variability was observed across individuals. Some of this variability was explained by level of injury, but other factors have not been completely identified. Further development and application of this rehabilitation tool to other diagnoses are expected in the future.

Center of mass acceleration feedback control of standing balance by functional neuromuscular stimulation against external postural perturbations.

This study investigated the use of center of mass (COM) acceleration feedback for improving performance of a functional neuromuscular stimulation control system to restore standing function to a subject with complete, thoracic-level spinal cord injury. The approach for linearly relating changes in muscle stimulation to changes in COM acceleration was verified experimentally and subsequently produced data to create an input-output map driven by sensor feedback. The feedback gains were systematically tuned to reduce upper extremity (UE) loads applied to an instrumented support device while resisting external postural disturbances. Total body COM acceleration was accurately estimated (>89% variance explained) using 3-D outputs of two accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, feedback control of stimulation reduced UE loading by 33%. COM acceleration feedback is advantageous in constructing a standing neuroprosthesis since it provides the basis for a comprehensive control synergy about a global, dynamic variable and requires minimal instrumentation. Future work should include tuning and testing the feedback control system during functional reaching activity that is more indicative of activities of daily living.

Center of mass acceleration feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations.

This study determined the feasibility and performance of center of mass (COM) acceleration feedback control of a neuroprosthesis utilizing functional neuromuscular stimulation (FNS) to restore standing balance to a single subject paralyzed by a motor and sensory complete, thoracic-level spinal cord injury. An artificial neural network (ANN) was created to map gain-modulated changes in total body COM acceleration estimated from body-mounted sensors to optimal changes in stimulation required to maintain standing. Feedback gains were systematically tuned to minimize the upper-limb (UL) loads applied by the subject to an instrumented support device during internally generated postural perturbations produced by volitional reaching and object manipulation. Total body COM acceleration was accurately estimated (>90% variance explained) from 2 three-dimensional (3-D) accelerometers mounted on the pelvis and torso. Compared with constant muscle stimulation employed clinically, COM acceleration feedback control of stimulation improved standing performance by reducing the UL loading required to resist internal postural disturbances by 27%. This case study suggests that COM acceleration feedback could potentially be advantageous in a standing neuroprosthesis since it can be implemented with only a few feedback parameters and requires minimal instrumentation for comprehensive 3-D control of dynamic standing function.

Single Channel Hybrid FES Gait Assist System

Loss of mobility due to lower limb paralysis is common consequence of thoracic level spinal cord injury (SCI). In the US there are approximately 253,000 persons with SCI. The wheelchair is the most common form of mobility for individuals with paraplegia but there remains a need for assistive technology that can enable paraplegics to walk and reach in the periphery of wheelchair. A new concept is presented that combines functional electrical stimulation (FES) with an energy storing orthosis (ESO) that contains a fluid power system to store and transfer energy during the gait cycle. Elastic energy storage elements on the orthosis hip and knee joints hold the leg in a flexed equilibrium position. Stimulation of the quadriceps extends the knee, placing excess energy in both the equilibrium spring and an energy transfer element. The stored energy is transferred to the hip where it is discharged and used to extend the hip against its equilibrium spring which also aids in forward progression. A new step is initiated by releasing the hip and knee joints from the straight leg position to the flexed position. The concept is realized using gas springs and pneumatic cylinders. Gas springs act as flexed energy storage elements. Lower air cylinder and the tubing acts as an accumulator and the upper cylinder acts as hip joint actuator. The system uses 2 way proportional solenoid actuated pneumatic valves for control during extension. The conceptual design of the ESO was completed and implemented in a dynamic simulation model (MSC ADAMS) and in a benchtop prototype for engineering measurements. Of the 14 joules of energy available from quadriceps, 8.9 joules of energy is utilized for doing work against springs and inertial forces; 5.4 joules is stored in pneumatic system; of which 1.4 joules is required for hip extensions and the remaining will be used for forward progression. No studies were conducted with human subjects. A hydraulic fluid power system was investigated for better control and braking possibilities but was not adopted because of difficulities in accumulator design and high fluid friction losses. A Matlab code was used to calculate the torques required at joints to support standing. Commerical braces are being used for improved user comfort. A wrap spring brake is being designed to maintain standing posture without FES or any active energy input. Technical feasibility of the ESO prototype will be evaluated using two subjects with paraplegia.

Design and Simulation of a Pneumatic, Stored-energy, Hybrid Orthosis for Gait Restoration

Loss of mobility due to lower limb paralysis is a common result of thoracic level spinal cord injury. Functional electrical stimulation (FES) can restore primitive gait in the vicinity of a wheelchair by using electrical stimulation to generate muscle contractions. A new concept for FES-assisted gait is presented that combines electrical stimulation with an orthosis that contains a fluid power system to store and transfer energy during the gait cycle. The energy storage orthosis (ESO) can be driven through a complete gait cycle using only stimulation of the quadriceps muscles. The conceptual design of the ESO was completed and implemented in a dynamic simulation model and in a benchtop prototype for engineering measurements. No studies were conducted with human subjects. The results demonstrate the potential of the ESO concept for a feasible gait-assist system and the validity of the simulation model as a means for designing the system.

Implantable FES system for upright mobility and bladder and bowel function for individuals with spinal cord injury

Postintervention. To determine the effectiveness of the Praxis multifunctional implantable functional electrical stimulation (FES) system (Neopraxis Pty. Ltd, Lane Cove, NSW, Australia) to provide standing and stepping ability and bladder and bowel management for individuals with motor complete thoracic level spinal cord injuries (SCI). Pediatric orthopedic hospital specializing in SCI. Three males, ages 17 and 21 years, with motor-complete thoracic level SCI and intact lower motor neurons to the muscles targeted for stimulation. Each subject was successfully implanted with the Praxis FES system. All three subjects received electrodes for upright mobility and the first two subjects received additional electrodes for stimulated bladder and bowel management. Following training, subjects were evaluated in their ability to use FES for nine mobility activities. Acute and chronic experiments of the effect of stimulation on bowel and bladder function were also performed. All three subjects could independently stand up from the wheelchair and could walk at least 6 m using a swing through gait pattern. Two subjects were able to independently perform swing through gait for 6 min and one subject was able to independently ascend and descend stairs. Suppression of reflex bladder contractions by neuromodulation (subject 1) and stimulated contractions of the rectum (subject 2) were observed in acute experiments. When stimulation was applied over the course of several weeks, a positive effect on bowel function was measured. Stimulated bladder contractions were not achieved. The feasibility of using the Praxis FES system for upright mobility and aiding aspects of bladder and bowel function was demonstrated with three subjects with thoracic level SCI.

Modeling of object movement capability in the spinal cord injured population

Static biomechanical modeling has revealed that human reaching and object movement capabilities are dependent on both torso and upper extremity muscle strengths, and the ability to maintain balance throughout the movement. This paper describes data and biomechanical models that can be used to understand the dynamic motions of people with and without thoracic level spinal cord injuries (SCIs) while moving objects around in their environments. This paper also discusses how data gathered in the Human Motion Simulation (HUMOSIM) Laboratory from volunteer subjects performing various seated tasks are used in multi-joint inverse biomechanical models to predict both shoulder moments and body center of pressure locations. The results demonstrate that when symptomatic control subjects moved a box from a small table in front of them to a shoulder-high shelf, it was performed in a smooth fashion that could be well modeled and understood with the use of sequential static biomechanical models. The motions of those subjects with thoracic and high lumbar level SCIs, however, contained an additional dynamic component. The dynamic component revealed that healthy, active SCI subjects were quite capable of extending the distance over which they can move objects to rigid shelves by using a ballistic motion technique. This dynamic motion allows them to move objects to shelves located over twice the distance predicted by static models of such motions, but also raises questions of safety due to falling forward if the object being moved does not land securely on the shelf. These types of motions also are shown to cause much higher (by about 30%) shoulder moments, thus raising the risk of injury to shoulder tissues in people with SCIs. Relevance to industry This paper shows that biomechanical models for predicting the capabilities of people to move objects when they have thoracic level spinal cord injuries (SCIs) will require dynamic elements to be carefully considered. It is believed that the results of the data and biomechanical modeling included in this study provide a scientific basis for improving design guides, so that in the future such workplaces will better accommodate people with SCIs.

Hypokinetic circulation in persons with paraplegia.

It is well established that hemodynamic dysfunction, resulting in diminished upper-extremity work capacity, occurs in persons with spinal cord injury (SCI) as compared with those who are nondisabled (ND). Although it has been shown that persons with paraplegia display higher values of heart rate (HR) with lower values of stroke volume (SV) during exercise, it is not resolved whether there is adequate compensation to produce similar values of cardiac output (.Q) as in ND. This study examined central cardiovascular responses (HR, SV, and .Q) of 20 subjects with complete thoracic level SCI (T(4)-T(11)) and 20 sedentary ND subjects during matched levels of arm-crank (AC) exercise. All subjects performed an incremental peak AC test to volitional exhaustion with continuous metabolic analysis and HR measurement via open circuit spirometry and 12-lead electrocardiography, respectively. Stroke volume was assessed using transthoracic impedance. Heart rate was higher for SCI (P< 0.05) with significantly lower values for SV and .Q at rest (approximately 25%). Peak responses were significantly higher for ND in all factors except HR. Although subpeak HRs at matched absolute workloads were significantly higher for SCI (12-20 beats.min (-1) ), SV and .Q were significantly lower (P< 0.05). The results of this study indicate that .Q is significantly lower in SCI than in ND during AC, despite significantly greater values of HR. These findings also suggest that the disparity in exercise values of .Q is related to differences exhibited at rest.

Control of neuromuscular stimulation for ambulation by complete paraplegics via artificial neural networks

The paper describes the application of a neural network (ANN) for controlling a functional neuromuscular stimulation (FNS) system to facilitate patient-responsive ambulation by paralyzed patients with traumatic, thoracic-level spinal cord injuries. The particular ANN that is employed is a modified Adaptive-ResonanceTheory (ART-1) network. It serves as a controller in an FNS system (the Parastep system) that is presently in use by approximately 500 patients worldwide (but still without ANN control) and which was the first and only FNS system approved by FDA. The proposed neural network discriminates above-lesion upper-trunk electromyographic (EMG) time series to activate standing and walking functions under FNS and controls FNS stimuli levels using response-EMG signals. For this particular application, several modifications are introduced into the standard ART-1 ANN. First, a modified on-line learning rule is proposed. The new rule assures bi-directional modification of the stored patterns and prevents noise interference. Second, a new reset rule is proposed, which prevents 'exact matching' when the input is a subset of the chosen pattern. A single ART-1-based structure is being applied to solving two problems, namely (1) signal pattern recognition and limb function determination, and (2) control of stimulation levels. This also facilitates ambulation of paraplegics under FNS, with adequate patient interaction in initial system training, retraining the network when needed, and in allowing patient's manual over-ride in the case of error, where any manual over-ride serves as a re-training input to the neural network. The ANN control facilitates continuous update of control settings during normal use, without formal retraining. [Neurol Res 2001; 23: 472-481]

Comparison of functional electrical stimulation to long leg braces for upright mobility for children with complete thoracic level spinal injuries

Objective: To prospectively compare functional electrical stimulation (FES) to long leg braces (LLB) as a means of upright mobility for children with motor-complete thoracic level spinal cord injuries (SCIs). Design: Intrasubject group comparison of two interventions. Setting: Nonprofit pediatric orthopedic rehabilitation facility specializing in SCI. Patients or Other Participants: Convenience sample of five children between 9 and 18 years old with motor-complete thoracic level SCI. The hip and knee extensors were excitable by electrical stimulation. Interventions: The FES system consisted of percutaneous intramuscular electrodes implanted to the hip and knee extensors and a push-button activated stimulator worn about the waist. Standing was accomplished by simultaneous stimulation of all implanted muscles. For foot and ankle stability, either ankle-foot orthoses (AFO) or supramalleolar orthoses were used. The LLB system consisted of a custom knee-ankle foot orthosis (KAFO) for four subjects and a custom reciprocating gait orthosis (RGO) for one subject who required bracing at the hip. For both interventions, either a front-wheeled walker or Lofstrand crutches were used as assistive devices. Each subject was trained in the use of both FES and LLB in seven standardized upright mobility activities: stand and reach, high transfer, toilet transfer, floor to stand, 6-meter walk, stair ascent, and stair descent. Main Outcome Measures: For each mobility activity, five repeated measures of level of independence, using the 7-point Functional Independence Measure (FIM) scale, and time to completion were recorded for each intervention. Subjects were also asked which intervention they preferred. Results: For 94% of comparisons, subjects required equal (70%) or less (24%) assistance using FES as compared with LLB. Six of the seven mobility activities required less time to complete using FES, two activities at significant levels. The FES system was preferred in 62% of the cases, LLB were desired 27% of the time, and there was no preference in 11% of the cases. Conclusions: The FES system generally provided equal or greater independence in seven mobility activities as compared with LLB, provided faster sit-to-stand times, and was preferred over LLB in a majority of cases. Follow-up evaluations of both modes of upright mobility are needed to compare long-term performance and satisfaction.

Validity and reproducibility of crutch force and heart rate measurements to assess energy expenditure of paraplegic gait

Objective: To determine the validity and reproducibility of heart rate (HR) and crutch force measurements to estimate energy expenditure during paraplegic walking. Usefulness of these outcome measures in comparative trials was assessed in terms of responsiveness. Design: Cross-sectional validity was determined using one single (first) measurement. Longitudinal validity as well as reproducibility were calculated using repeated measurements. Setting: Oxygen uptake and HR during steady state as well as axial crutch load were measured at subjects' self-selected walking speeds. Patients: Ten subjects with thoracic-level spinal cord injury were included in the study. All subjects had considerable experience with ambulation in the advanced reciprocating gait orthosis (ARGO). Main Outcome Measures: Oxygen uptake (V̇O 2, mL/min) and oxygen cost (Eo 2, mL/m) were used as criterion standards. Crutch peak force (CPF), crutch force time integral (CFTI), HR, and physiological cost index (PCI) were used to estimate energy expenditure. Results: The PCI was found to be sensitive to detect differences between sessions in criterion standard ( r = .86). Smallest detectable difference (ie, point where difference exceeds measurement error) ranged from approximately 15% for CPF to 33.7% and 41.8% for Eo 2 and PCI, respectively. Conclusions: Although PCI is expected to be a valid measure for within-patient differences in V̇O 2, responsiveness was lower compared to Eo 2 and CPR. The limited number of patients who can be included in studies on paraplegic locomotion requires reproducible outcome measures. Therefore, CPF and Eo 2 are advocated in favor of PCI.