Walking for the severely disabled: research and development, experience and clinical outcomes.
Explore the source record for details and available documents.
Costs and Cost Analysis↗
Biomedical subjects
J Stallard
Publications and source records attributed to J Stallard.
Performance specification for lower limb orthotic devices.
OBJECTIVE: To establish the range of forces and moments applied to lower limb orthoses during ambulation by routine users. DESIGN: Well-established gait analysis techniques were used to determine the loading at the major joints. It was assumed that the joint moments were transmitted by the orthosis encompassing any particular joint. Two hundred and five assessments of 164 patients were successfully completed by a consortium of four gait laboratories in Europe. The orthosis specification and patient clinical data were also recorded. BACKGROUND: The design and development of orthoses has occurred largely by evolution rather than by formal engineering methods. In particular, formal design has been hampered by a lack of information on the forces and moments applied during ambulation. METHODS: A standard gait analysis procedure was employed to capture the data. In-house biomechanical models were used to calculate the joint loading. Data were normalised with respect to patient weight and leg length. RESULTS: It was found that the median maximum normalised ankle moment transmitted by an ankle foot orthosis was 0.15 and the maximum knee moment was 0.09. The greatest moment transmitted by the hip joint of a hip knee ankle foot orthosis was also 0.09. There was a wide variation in the data due to differences in the impairments of the test subjects. CONCLUSION: It is possible to estimate the loads transmitted by an orthosis using established gait analysis procedures without the need for load measurement transducers. There is now a need both to collect a larger representative dataset and to perform validation studies with transducers.
Adolescent↗
Transportable two-dimensional gait assessment: routine service experience for orthotic provision.
PURPOSE: The purpose of the pilot service was to establish the potential of the newly developed system to achieve, in a community setting, more effective orthotic outcomes for patients in whom alignment of ground reaction force is an important treatment objective. METHODS: Twelve visits were arranged to a paediatric community physiotherapy department. Up to six patients at each visit were selected for assessment of their lower limb orthotic prescription. The patient's gait was assessed using the video vector generator to determine alignment of ground reaction force. Where necessary, adjustments to the orthotic set-up were made to achieve more closely the stated objective. At the conclusion a specification of the orthosis was agreed. RESULTS: In only two of 61 assessments that were conducted was it not possible to achieve a useful outcome. CONCLUSIONS: Improvements in biomechanical alignment were achieved in more than 68% of assessments. The pilot service was sufficiently successful for it to be extended to a routine clinical service.
Adaptation, Physiological↗
New technical advances in swivel walkers.
Swivel walkers were commonly prescribed for children with complete thoracic lesion myelomeningocele in the 1970s and 80s, when the incidence of spina bifida in the UK was of the order of 3 per 100,000 live births. The advent of reciprocal walking orthoses provided a more suitable alternative for those with good upper limb and trunk function, and swivel walkers were then used primarily for very young or more severely disabled patients. Pre-natal screening has dramatically reduced the incidence of spina bifida in the UK and subsequently swivel walkers have been used in a wider range of pathology, including spinal muscular atrophy, multiple sclerosis, muscular dystrophy and other neurological conditions that lead to lower limb dysfunction. The detail design of these devices has been adapted to accommodate the specific problems encountered in these conditions. In particular the designs have been updated to: enable very young patients to be more readily fitted at the age of 1 year; allow the walking mechanisms to be conveniently adjusted for easier ambulation when weakness or lack of confidence inhibits performance; permit simple adjustment to a standing frame mode to enhance stability in situations of increased risk; promote manual handling practice that is compatible with the National Health Service (NHS) policy of compliance with relevant regulations. To underpin appropriate prescription and safe supply the NHS Procurement Agency have encouraged the development of a common course for all types of swivel walker.
Adolescent↗
Reciprocal walking orthosis with composite material body brace: initial development.
Reciprocal walking orthoses are routinely used by thoracic lesion patients for ambulation using crutches. A primary reason for their prescription is to provide therapeutic benefit and improved independence. To achieve this, maximum efficiency of walking and acceptance of the device is necessary to promote long-term compliance. Lateral rigidity in the orthosis influences walking efficiency, but the structural properties of conventional techniques for producing a sufficiently rigid body brace makes them unattractive. Currently patients and clinicians are forced to choose between greater efficiency or cosmesis of the orthosis. Composite materials have the potential to permit the required rigidity in a structure that is less obtrusive. However, their material properties could lead to unsafe forms of failure unless suitable manufacturing methods are devised. It is therefore inappropriate to supply prototypes to patients for field evaluation until laboratory investigation of innovative production methods has ensured that the orthosis is safe. A production technique has been devised that is ostensibly suitable. Prototype body braces have been tested and have been shown to have improved structural properties and safe failure modes. A test programme implemented on a complete concept orthosis has confirmed that improved lateral rigidity can be achieved with a less obtrusive body brace, and that it will behave safely for long enough to permit field evaluation.
Braces↗
Evaluation of safety and reliability in an infant reciprocal walking orthosis.
In response to new demands for infant walking orthoses consideration was given to the development of a device for this category of patient. A specially developed hip joint with the required structural properties (Woollam et al., 2001) provided an opportunity for this development. Earlier structural assessment, and limited cyclic load testing of key elements of the orthosis (primarily the body brace), confirmed that a safe device for evaluation with patients could, theoretically, be produced. A provisional prototype was therefore designed and manufactured for initial structural testing of the complete infant orthosis (Stallard et al., 2001). Efficiency of walking is strongly influenced by the lateral rigidity of the orthosis. Monitoring the structural performance of the provisional infant design indicated it would equal or improve on the stiffness of that achieved in the adult specification. Additionally, relative strength was comparable with the adult version, which has proven to be safe and reliable in many years of routine prescription. This, together with the limited cyclic testing of the complete orthosis (Stallard et al., 2001), gave confidence that it was safe to proceed with controlled field evaluation of the infant design when supplied as a rehabilitation engineering device within the provisions of an ISO9001 and EN46001 QA System. This additional study of controlled patient use, and further representative cyclic load testing in parallel with the field evaluation, had established the long-term structural safety of the orthosis. Wider application is now to be introduced through completion of the EC (European Community) Medical Devices Directive formalities.
Humans↗
Structural design and performance of a rear support walking frame.
Rear support walking frames provide predetermined vertical support for patients with dysfunctional lower limbs that have limited active control; the support is provided through a spring-loaded boom hinged on an upright stanchion mounted at the rear of a wheeled frame within which the patient ambulates. The application of these frames for total-body-involved cerebral palsy patients, in combination with a walking orthosis, has highlighted a number of practical problems that need to be addressed for the system to become fully viable. A composite material prototype walking frame has been developed that permits the patient to be transferred by a single carer without the need to use inappropriate manual handling techniques. The frame has improved structural properties, with stiffness in the sagittal and coronal planes increasing by between 50 and 100 per cent. Evaluation with patients showed that the greater structural stiffness permitted the objective of improved continuity of walking to be achieved. The strength of the frame is such that it can accommodate patients of up to 80 kg, more than twice that possible in the earlier system. Since the structural yield point is approximately twice the maximum working load, the device should not be prone to unacceptable fatigue characteristics. Despite the use of carbon composite materials (which have brittle failure characteristics), the mode of failure is of progressive collapse and is therefore inherently safe. The successful outcome of prototype testing has justified production development. Work is now proceeding on a design that incorporates further improvements in structural performance and ease of manufacture.
Biomechanical Phenomena↗
A long-term review of severely disabled spina bifida patients using a reciprocal walking system.
PURPOSE: The purpose of the study was to establish long-term compliance of paediatric spina bifida patients using a reciprocal walking orthosis, prescribed to enhance function and long-term therapeutic benefit. METHODS: Data from current clinical notes of 28 spina bifida patients prescribed with the Parawalker reciprocal walking orthosis between 1973 and 1984 were compared with those established for the purposes of research at the time of original prescription. Patients were supplied via an on-going treatment regime by a specialist multi-disciplinary team. Regular follow-up was an essential element of the clinical policy. This enabled effective monitoring of patient performance and requirements. It also ensured that accurate data was maintained. Clinical and walking performance details were recorded at the time of supply. Current clinical notes from routine follow-up reviews for patients in the study were scrutinized to establish present status, ambulation performance and medical history. RESULTS: Fourteen patients had thoracic lesions the remainder having high, mid lumbar or variably diagnosed lesions. The period of use ranged from 4.6 to 18.1 years (average = 9.71 years) The orthosis was first prescribed at 3.6 years to 13.9 years. Discontinuation occurred at between 11.2 and 23.9 years. None of the patients suffered a pressure sore or bone fracture. CONCLUSIONS: Long-term continuation of reciprocal walking within a controlled treatment regime was established. This enabled confirmation that comprehensive health care systems can achieve improvements in patient function, together with overall cost savings because of the reductions in pressure sores and bone fractures identified for such activity.
Female↗
A reciprocal walking orthosis hip joint for young paediatric patients with a variety of pathological conditions.
A growing trend in the use of reciprocal walking orthoses for infant paraplegic patients, and their application for control of the lower limbs in very young total body involved cerebral palsy patients, has created a need for smaller components. A prototype design of a hip joint has been produced which provides the following features: adjustable range of flexion/extension control; override on stops to permit sitting; high lateral rigidity; no lateral bearing play; very high rigidity in the sagittal plane; low friction bearings; high resistance to torque about the vertical axis. In addition a size envelope which is more in keeping with the dimensions of infant patients was an important objective. Comparisons were made of the computed structural properties of the prototype joint and existing routinely available standard orthotic hip joints. In each plane of loading the prototype joint had the highest identified structural property. The hinge-bearing material was tested in a representative joint with 200,000 cycles of typical loading. It was also field tested on adult orthoses over a minimum of a 12-month period with the most vigorous of walkers. In neither test did excessive play develop. The mechanical properties of the joint were established using tests advocated in the British Standard on testing lower limb orthosis knee joints. These showed the joint had structurally equivalent performance to a successful reciprocal walking orthosis hip joint, and that the mode of failure was essentially ductile in nature. Production development of the joint is now being undertaken.
Biomechanical Phenomena↗
An infant reciprocal walking orthosis: engineering development.
The growing trend of prescription of reciprocal walking orthoses for children under the age of 5 years has created a requirement for a new design of orthosis in this category. In response to this new demand, a prototype orthosis for infants, incorporating a specially developed hip joint and manufactured as a rehabilitation engineering device within the provisions of the EC Medical Devices Directive, has been produced and tested. A design feature that strongly influences the efficiency of walking is the rigidity of the body brace structure. Monitoring the specific structural performance of the body brace intended for infants showed that it would equal or improve the stiffness achieved in an orthosis for adults. Additionally its strength was comparable with the adult design, which has proven to be safe and reliable in many years of routine prescription. Incorporation of the infant body brace within a complete orthosis provided a structure of more acceptable physical dimensions for these more diminutive patients. The orthosis showed no incipient sign of failure after 100,000 cycles of representative service loading equivalent to that imposed by a 20 kg (5-year-old) patient. The results of structural assessment and cyclic load testing confirm that the design of the orthosis sufficiently satisfies the statutory requirements for devices that are safe and fit for purpose to permit field trials with patients.
Biomechanical Phenomena↗
Sludge digestion enhancement and nutrient removal from anaerobic supernatant by Mg(OH)2 application.
Anaerobic sludge digestion is a widely adopted process for sludge stabilization. Phosphate removal from anaerobic supernatant is necessary to limit the phosphate returned to the head of the treatment plant, thereby improving the overall treatment efficiency. In this study, magnesium hydroxide (Mg(OH)2) was used to improve the sludge digestion efficiency and to remove phosphorus from anaerobic supernatant. The anaerobic sludge digestion experiment was conducted at a pilot scale, and the results showed that applying Mg(OH)2 to anaerobic sludge digester resulted in a larger reduction in SS and COD, a higher biogas production rate, a lower level of phosphate and ammonia nitrogen concentrations in the sludge supernatant and an improved sludge dewaterability. Research results at both lab scale and pilot scale on phosphorus removal from anaerobic supernatant using Mg(OH)2 showed that a high removal of phosphorus can be achieved through the addition of Mg(OH)2. The required reaction time depends on the initial phosphorus concentration and the Mg(OH)2 dosage.
Ammonia↗
A rear support walking frame for severely disabled children with cerebral palsy: initial development.
Ambulation for patients with total body involved cerebral palsy poses greater problems than those encountered in providing reciprocal walking for thoracic lesion paraplegic subjects. Experience with a prototype system showed that an orthosis which controls the movement of the lower limbs, in combination with a walking frame giving anterior support, enables such patients to walk. Despite shortcomings which restricted the use of the system to an indoor environment it provided a sound basis on which to examine walking frames to address the problems which had been identified. A review of these devices showed that the most effective means of achieving this aim is the use of a wheeled walking frame which provides vertical support and truncal alignment via a sprung pantograph mounted to the rear of the patient (rear support walking frames). Trials were conducted with two existing rear support walking frames. These indicated their potential for severely disabled patients, but also identified the need for higher stiffness in the structure and more sensitive control of vertical support to be achieved if effective ambulation in a wider range of environments was to be made possible for the target group. Prototypes based on an existing frame, which took account of the specification requirements, were produced for four new total body involved cerebral palsy patients with the same degree of walking dysfunction. Three of the patients were able to walk in a much wider variety of environments than any patient in the original system. A number of other issues related to transfer and steering were identified as requiring further development.
Adolescent↗
Feasibility study on a composite material construction technique for highly stressed components in reciprocal walking orthoses for paraplegic patients.
Reciprocal walking for thoracic level paraplegic patients using reciprocal walking orthoses has become a routine treatment option. Two general design options are currently deployed within an overall treatment regime. Research has shown that one has better walking efficiency but is cosmetically less acceptable to the patient. Design analysis and experimental data have shown that a major factor in improved walking efficiency is the lateral stiffness of the body brace section of the orthosis. This is the area where problems of cosmesis in the more efficient orthosis are perceived because of the employment of metallic structures. The use of composite material structures to achieve shapes which are more closely conforming to the patient is an attractive option. However the brittle nature of these materials makes it unlikely that the requirement for the ductile failure mode will be achieved from a straightforward moulding. A new construction technique has been devised which has the potential to provide a safe failure mode with greater stiffness and lighter weight. This feasibility study has been undertaken to demonstrate its potential so that further work can be justified which will provide sufficient evidence to support a patent application. The successful outcome of the study, in which stiffness was increased by 60 per cent with a weight reduction of 50 per cent and a failure mode comparable with the original metal structure, suggests that further work will enable the dilemma in the choice of orthosis to be resolved.
Braces↗
Preliminary clinical experience of a contracture correction device.
Joint contractures which do not respond to conventional physiotherapy can be difficult to treat. Serial plastering has been used effectively but is expensive, inconvenient to the patient and does not permit daily hygiene or clinical inspection. A mechanical device has been developed consisting a hinged orthosis which spans the affected joint to which is attached a gas strut to provide a corrective moment about the anatomical joint. Such an arrangement enables prescribed corrective moments to be applied accurately following clinical assessment using routine physiotherapy techniques. The inherently low spring rate of a gas strut ensures that the specified corrective torque is maintained as correction occurs. Initial treatment experience under the control of the developers had generated wider interest in the system. A geographically distant independent orthotic supply centre was trained in the techniques of application. They treated nine elbow and three knee joints in patients who had not responded to physiotherapy treatment. All of the patients experienced improvement. The average for elbow joints was a reduction in the contracture of 25.6 degrees with a corrective moment of 6.8 Nm over a period of 3.9 weeks. For the knee joints the averages were a reduction in contracture of 10.7 degrees with a corrective moment of 12.7 Nm over a period of 4 weeks. The results confirmed the practicality of transferring the system to independent clinical centres and provide evidence to support funding for a formal prospective clinical trial of the treatment approach.
Adult↗
A review of reciprocal walking systems for paraplegic patients: factors affecting choice and economic justification.
The prescription of treatment systems which include orthoses to enable patients with high level thoracic spinal lesions to walk reciprocally is now widely practised. It remains a clinical option for which the efficacy is frequently called into question. A broad range of experience has now been accumulated with orthoses of this type, and this is reflected in the literature. The indications for prescription and outcomes of treatment have, as a result of the reported research, become clearer. However, the length of time over which the relevant work has been published and the variety of journals in which it has appeared makes it difficult to perceive a coherent message. This review analyses the published work in order to identify the degree to which the therapeutic benefits which can accrue from ambulatory activity produce an economically justified outcome. Provided appropriate supply procedures are observed so that good patient compliance with the treatment is achieved, there is strong evidence that fewer pressure sores and improved independence will occur at a level where real overall cost savings can be made. Factors which affect patient compliance and on which research findings have been published are identified. Comparisons are made between different orthoses with regard to these, so that more informed choice, taking into account preferences of individual patients, can be made by clinicians.
Humans↗
A review of 42 patients of 16 years and over using the ORLAU Parawalker.
A 7 year retrospective review of 42 patients of 16 years or over using the ORLAU Parawalker has been conducted to establish the degree of long-term compliance in using the orthosis on a regular basis. Regular use was defined as putting the orthosis on at least once a week. All subjects had been supplied with an ORLAU Parawalker via the routine supply procedures adopted in Oswestry, and were followed up at regular 6 month intervals as part of the standard treatment regime. The records from routine follow-up were surveyed for those patients who were continuing to use their orthosis to establish age, length of time since supply of orthosis and cause of lesion. Average period of usage is calculated for those still using their orthosis, and for all patients in the study. Of the 42 subjects, 32 were myelomeningocele patients with confirmed absence of innervation of hip extensors and abductors, the remainder being paraplegic patients with traumatic or acquired complete thoracic lesions. Compliance figures were extracted from the results, as were the minimum possible average periods of usage. The respective results were: of the 32 myelomeningocele patients 59.4% continued usage after an average period of 85.5 months, and of the 10 traumatic or acquired lesion patients 60% continued usage after an average period of 24.8 months respectively, which gave a combined compliance of 59.5% after a minimum average 71.1 months of use. The performance or myelomeningocele patients suggests that their additional deformities do not lead to inferior compliance as adults and that a high proportion to continue to walk after adolescence.
Adolescent↗
The potential for ambulation by severely handicapped cerebral palsy patients.
Whereas walking for paraplegic patients is now a routine clinical option, ambulation for heavily handicapped cerebral palsy patients is less well established. There are good reasons for supposing that therapeutic benefits similar to that achieved with paraplegic patients are possible for this group. However, the biomechanical problems which must be overcome are different and in many ways more difficult to address. The most important factors are identified as appropriate truncal support, control of abduction/adduction, rotation and flexion range at the hip, and of knee flexion. A means of applying these controls is described as being a combination of a walking frame and orthosis. The special walking frame provides adjustable support at thoracic, abdominal and sacral levels and incorporates castor steering and upper limb support. Controls on lower limb movements are applied through a special orthosis which has a readily available variation of specification to accommodate the wide range of conditions met in cerebral palsy. Practical application of a prototype system has shown that it can enable patients to walk unaided. However, in most cases it was used indoors only. Evaluation of the experience in applying the system has enabled the fundamental principles to permit more practical applications to be defined.
Biomechanical Phenomena↗
Energy cost of walking.
Explore the source record for details and available documents.
Energy Metabolism↗