Low Cost Modified Reverse Walker to Assist Children with Cerebral Palsy in Hands-free Walking: A Pilot Study

Introduction

According to World Health Organization (WHO) estimation, 10% of the global population has some form of disability due to different causes; in India, it is 3.8% of the population. Nearly 15-20% of the total physically handicapped children suffer from cerebral palsy (CP). For India, the estimated incidence is around 3/1000 live births; however, being a developing country, the expected actual figure may be much higher.¹ Independent ambulation is of great importance in most cultures, and walking is a motor milestone of major significance to parents of children with cerebral palsy (CP),² which is a non-progressive disease due to damage to the brain before, during or shortly after child’s birth.^3,4 Treatment of cerebral palsy is a lifelong process focused on the management of associated conditions. Brain up to about the age of eight is not completely developed and has the ability to rewire many signalling pathways that may have been affected by initial trauma; the earlier it is modified, the more successful it will be.³

It is essential to develop good hand function along with walking for many reasons⁵ and childhood is the ideal age for learning motor skills.⁶ Thus, it is crucial that they are exposed to the opportunities to develop their skills as much as possible. There is no availability of walkers which allow hands-free walking for children with CP in the Indian market. It is available in the international market, and few renowned wheeled walkers that allow hands free walking for children with CP are as follows:

1. Mulholland walkabout gait trainer (Figure 1 and 2)⁷- it is a posterior, weight-relieving gait trainer. It is handsfree and it is open in the front. It costs 2,660 US dollars which is approxiately 1, 63,989 rupees, 2. Buddy roamer posterior walking aid (Figure 3 and 4)⁸ , It is designed to support body weight while allowing the child to walk around freely and unaided. It costs 4,169 US dollars, which is approximately 2, 57,019 rupees, 3. Hart walker (Figure 5 and 6)⁹ - Hart Walker aims to make progress towards independent mobility, allowing a child to stand with a good posture and learn to walk with an efficient walking pattern, without the need to use their hands. It costs 12,000.00 US dollars, which is approximately 7, 39,800 rupees.

Wu et al¹¹ in a retrospective cohort study to determine independent predictors of ambulation among children with cerebral palsy and to develop a simple tool that estimates the probability that a child will walk (n=5366) reported early motor milestones such as sitting and pulling to a stand as independent predictors of successful ambulation. Molnar GE et al.¹² in a prospective longitudinal study to select signs useful in predicting early prognosis regarding ambulation in children with cerebral palsy (n=233), followed these children starting at 12 months until they attained 3 to 11 years og age. The study observed that the probability of ambulation was related to the clinical type of cerebral palsy.

Rodby-Bousquet et al.¹³ conducted a cross-sectional study (n=562) to measure walking performance while looking at variations in distance and environments, and their effect on gross motor function, CP subtype, and age. The study reported that the overall walking performance improved at 7 years of age, but the proportion of children walking independently on uneven surfaces improved in increment in each age group up to 18 years.

Park et al.¹⁴ conducted a comparative study to compare gait pattern and energy consumption in children with spastic diplegic cerebral palsy, when comparing between an anterior and posterior walker to determine which walker is effective as a walking aid in these children. Ten spastic diplegic cerebral palsied children, with an average age 9 years were selected. Gait analysis data and oxygen consumption measurements indicated that the posterior walker was advantageous over anterior walker in terms of upright positioning and energy conservation.

Type, age at intervention and type of walker were some of the major factors obsered to have a significant effect on ambulation prognosis in CP. Therefore, this study was designed considering these factors to develop a low cost modified reverse walker to assist children with cerebral palsy in hands-free walking, enable good posture and social interaction. Model modification provides the child with a bracing around pelvis and thorax. Model seat harness provides support to the child’s body weight while using the walker.

Materials and Methods

This was an experimental study that developed and evaluates a new model of walker for pediatric rehabilitation with CP. This study recruited 5 participants as per the inclusion and exclusion criteria. Informed written consent in the format approved by the Institutional Ethics Committee was obtained from all the participants before starting the study.

Inclusion and exclusion

criteria Participants with Level II (until age 4), Level IIIIV, as per gross motor function classification scale (GMFCS),10 children with delayed developmental milestones, diagnosed with cerebral palsy and can stand independently or with minimal support, children with cerebral palsy with the ability to propel their body forward while walking with support were included in the study.

Children with quadriplegic CP, cannot sit independently, contractures in lower extremity, inadequate muscle tone and muscle strength, behavioral problems (hyperactive), height exceeds the reverse walker limit and severe scissoring gait were excluded from the study.

Technical distribution of the walker developed

The newly developed low cost modified reverse walker was made up of the following parts: reverse walker (used R-frame reverse walker for further modification, adjustable posterior trunk support attchment (APTSA) and seat harness.

STEP 1 - Measurements Circumferential and mediolateral measurements were made at the pelvis in between the iliac crest and the greater trochaner (GT), and at the thorax, 2 inches below the inferior angle of scapula. Distance between GT and ground and in between iliac crest and GT, and 2 inches below inferior angle of the scapula till ground for calculating the distance of adjustable posterior trunk support attchment (APTSA) fixation point to reverse walker.

STEP 2 – Fabrication of APTSA Head rest, posterior shaft , clamps, pelvic and thoracic band were fabricated. Two pipes were were used with a linear measurement in between 2 inches below the scapula, and between GT and iliac crest, while keeping some extra length for adjustment. Two pieces of pipes were used for the APTSA posterior shaft attachment with the reverse walker. Fabrication of clamps: Four plastic clamps (Figure 7) were made out of 4mm polypropylene plastic (PP) squares of 12x12cm dimension (Figure 12).

Fabrication of the pelvic and the thoracic band : Two inches wide aluminium bands were cut to the measure of half of thoracic and pelvic circumference (Figure 8).They were bent to shape using an apparatus bender to match the medial-lateral dimension of pelvis and thorax. Nylon webbings (1.5 inches wide) were cut to make straps. Plastic buckles were stitched to the straps. Straps were fixed to the bands with speedy rivets.

Fabrication of head-rest: A length of CPVC equivalent to the distance between positions of two metal clamps was taken. CPVC elbows were fixed to both sides of that pipe segment. The length was checked by fitting it onto the posterior shafts after assembling them. Once correct length was achieved, head-rest was covered with 8mm ethaflex using contact adhesive (Figure 9).

Assembly of parts : Metal clamps were attached to the bands at ¼ distances from both ends with copper rivets. Metal clamps were secured to the plastic pipes with screws. Plastic pipes were clamped to the reverse walker with plastic clamps. When assembling the walker, plastic clamps were attached to the posterior top bar of the walker. The clamp with small diameter channel was attached to the walker and the clamp with the larger diameter channel was attached with the posterior shaft of the device. The middle plate with rubber was fixed with rubber facing the walker pipe.

STEP 3 – Fabrication of Seat Harness : Two different patterns were made. The patterns were tested on the subject and the larger one was chosen. The pattern was drawn on canvas cloth, and drill cloth. Nylon webbing reinforcement was designed as an “X” pattern and stitched onto the canvas cloth and drill cloth was sewn on top of that. Four 1.5 inches nylon webbings were stitched securely on each end of the “X” pattern. Trial of the fabricated temporary harness was performed. After necessary modifications, one layer of sponge padding was added for better cushioning. The seat harness (Figure 12) was attached to the walker with its posterior straps on the posterior top bar of the walker and the anterior straps were attached to the respective side bars, anterior to the handles.

Results

The participants were more confident and independent in walking without holding the reverse walker frame during pilot study. It was also observed that the children needed some time to accept this new device. During trial it is found that few participant were walking with support initially. Overall the device provided adequate trunk support and participants were able to walk without hand support eventually. It was observed that participants were able to achieve good standing posture which enabled them to play and have good social interaction. Parents were happy to see independent walking with modified reverse walker and purchased the walker. Cost of this low-cost modified reverse walker is much less than the other walkers available in the global market. This device is an innovation in the field of pediatric rehabilitation with great application.

In Table 1, the lowest mean in this data set is 4.89 (SD = 0.26) for the Device with a minimum score of 4.43 and a maximum score of 5. The highest mean is 5.00(SD = 0.00) for Services with a minimum and a maximum score of 5. So overall, the device performed successfully.

Discussion

According to World Health Organization (WHO) estimation, incidence of cerebral palsy is around 3/1000 live births in India¹ . These children required assistance for ambulation and therefore developing a walker suitable and affordable to the Indian market is a need of the hour. The first trial was conducted and was observed that APTSA has adequate fitting. It was reported that the pelvic belt and chest belt were short, and buckles needed augmentation to prevent them from slipping off the belt. Hence, plastic triglides were added. It was seen that the posterior shaft wasn’t perpendicular but obtuse and tilting backwards due to thickness of the CPVC elbow. To correct this, a square of 3 mm polypropylene was inserted between top portion of the plastic clamp and metal bar of the walker. Also, it was found that the ethaflex padding kept slipping down, so we needed some measure to fix it into place and added velcro to the ethaflex paddings.

Second trial was conducted using different reverse walker frames, and it was found that the device worked best on R-frame reverse walker. It was very unstable and tended to tilt forward and back excessively in B-frame reverse walker. Thus, R-frame reverse walker was chosen for the trials. The R-frame reverse walkers were found to be effective in terms of hands free ambulation for children with cerebral palsy. This device can be assembled in any orthopaedic workshop using locally available materials.

This low cost modified reverse walker was developed using all low-cost readily available material such as polypropylene sheet, chlorinated polyvinyl chloride tube, fabric, aluminum sheet pieces, sponge etc. Material cost was approximately 2500 Indian rupees to fabricate all the attachments of the modified gadget. Cost of the reverse walker was approximately 8000 rupees and so the total cost of the complete device was approximately 14000 rupees including other wages, which is very less when compare to other devices in the global market.^7,8,9

Advantages

Hands-free walking allows children to explore, discover and learn by interacting with the environment. This provides good trunk support by maintaing upright posture, prevents cardiovascular and musculoskeletal degeneration.¹⁴ It facilitates neural development. This device can be easily disassembled and folded by the caregiver providing portability and occupies less space when stored.

Disadvantages

It cannot be used on staircase, slopes and uneven surfaces without support or supervision of the caregiver.

Future recommendation

Future studies should be conducted as double-blind, randomized trials. A mechanism to prevent scissoring gait should be added to enhance its application. Use of metal instead of plastic to make posterior shaft and clamps to increase the strength of the device is recommended.

Conclusion

Low-cost, modified reverse walker allows the child with cerebral palsy to play and aids them to develop their skills, enjoy social interaction, thereby increasing their self-confidence and self-worth which are essential for a happy life. A reverse walker was chosen because of its four wheeled frame, and posterior ratchet wheels that offer stable brace using which a child can be encouraged to achieve a good standing posture and efficient walking pattern. The four wheeled frame of a reverse walker has adjustable front swivel wheels which respond immediately to the direction of walking and can be made to turn on the spot. The walker height and wheelbase can also be adjusted to the child’s height.

Conflict of interests

Authors declare that there is no conflict of interest.