When Donovan was 2 years old, he fractured his left femur. His injury appeared to resolve without complications, but Donovan's family noticed changes in his walking. At age 4, these subtle signs were thought to be associated with his early fracture. An orthopedic surgeon confirmed that Donovan's fracture was fully healed, so Donovan's family pursued complementary care to improve Donovan's mobility. When a chiropractor pointed out that Donovan's abnormal mobility did not appear to be associated with his earlier injury, Donovan was referred to a neurologist at Gillette Children's Specialty Healthcare in St. Paul, MN. Much to their surprise, at age 6, Donovan was diagnosed with a dystrophinopathy, commonly known as muscular dystrophy.
Muscles Beyond Repair
Muscular dystrophy describes a constellation of disorders affecting muscle structure and function. Dystrophinopathy is a particular variant wherein a gene on the X chromosome is abnormal, causing the body to lack the protein dystrophin (Duchenne muscular dystrophy), or to make abnormal dystrophin (Becker muscular dystrophy). The gene is recessive, meaning both chromosomal pairs would typically need to be affected for the condition to manifest. Since the defective gene is located on the X chromosome, dystrophinopathy typically affects males, sparing females with two X chromosomes.
Dystrophin helps bind together the muscle cell wall and maintain its integrity. If dystrophin is absent or functioning abnormally, the cell wall degenerates under the mechanical stresses of repeated contraction and relaxation. Excessive stress or fatigue of the muscle, such as with eccentric contraction, may exacerbate the condition. The deterioration allows intracellular material to leak into the intercellular space, leading to further muscle impairment. As the cell wall attempts to repair itself, a degradation, inflammation and regeneration cycle ensues without the necessary proteins to repair normally. Healthy muscle cells are replaced with fibrotic and adipose tissues, resulting in a weakened muscle with propensity for contracture.
The Duchenne and Becker muscular dystrophy (DMD and BMD, respectively) phenotype includes muscle weakness, mild hypotonia and psuedohypertrophy, especially in the calves. Muscle weakness is generalized and systemic, with some fibers seemingly more affected than others. Shoulder or hip girdle weakness is often more notable than distal muscle weakness. The ratio of the size of the body part to be moved to the muscles may be involved, and likely has biomechanical implications in terms of lever arm function.
Effects on the System
Systemic muscle weakness leads individuals to initiate compensatory patterns to maintain mobility. Notable is the Gower's maneuver when rising from the floor to standing. Individuals maintain their center of gravity anterior to the hip and knee, to compensate for weak hip and knee extensors. Toe walking is employed, to use knee extensor/ankle plantarflexor coupling to control the knee joint in stance. Excessive lumbar lordosis and scapular winging can be prominent.
Recently, the role of dystrophin in the brain has been identified, and may lead to learning disorders and other cognitive manifestations in DMD/BMD. As skeletal muscle deteriorates, mobility becomes increasingly affected, in many cases leading to an inability to walk, or reliance on a mobility device for community distances. More severely affected individuals are often unable to walk by their early to middle teens.
As individuals become less ambulatory, the effects on their musculoskeletal, cardiovascular, respiratory and gastrointestinal systems are compounded. Increased sitting versus standing and walking can decrease bone density, and a lack of movement can lead to fixed contracture. Cardiac muscle function is diminished, especially in the left ventricle. Weakened respiratory muscles coupled with compaction of the thorax in sitting lead to decreased lung function. Core weakness and upper-extremity compensatory patterning can lead to scoliosis, further hampering cardiac and respiratory function.
Limited mobility can exacerbate poor gastric motility, leading to constipation and nutrition issues. Finally, the overall decrease in mobility, increased dependence on caregivers and the cognitive manifestations of dystrophinopathy can lead to psychological and emotional challenges. Sitting for the majority of the day, below eye level of your peers, can create not only a physical immobility syndrome but also social isolation.
Diseases like DMD/BMD have systemic manifestations, requiring management by a team of professionals who understand the disease itself and the effects on development. The Neuromuscular Clinic at Gillette Children's Specialty Healthcare includes neurologists, orthopedists, physical medicine and rehabilitation specialists, pulmonologists, cardiologists, psychologists, geneticists and other specialists to properly diagnose and establish a treatment plan for individuals with neuromuscular diseases.
Physicians and nurse practitioners are complemented by nurses and coordinators, genetic counselors, occupational and physical therapists, speech/language pathologists, respiratory therapists, social workers and other allied health clinicians. Among this team, the physical therapist often addresses maintaining or improving muscle function and flexibility, mobility and body mechanics. A PT may also address equipment needs in conjunction with the team members. As individuals become less ambulatory, they require assistance to maintain weight-bearing through their legs and function upright for activities of daily living. A standing frame or stander may be prescribed for use to mitigate the effects of immobility.
A stander helps maintain upright weight-bearing in the absence of functioning postural muscles. A stander provides stationary control, and has been shown to have little positive effect on ambulation. Standers may support individuals in a prone or supine configuration, or may allow them to move from a fully sitting position to partially or fully standing. Increased awareness of the effects of immobility and understanding of the needs of non-ambulatory individuals have driven improvements in features, design and function.
Evaluating a patient's need for a stander begins with an assessment of function and ability to participate in activities. While most standers are prescribed for non-ambulatory patients, patients who cannot walk an appreciable amount should also be considered as potential users. Since it may take up to four hours of total stretch to create a change in muscle length, obtaining a stander for any individual who is upright for less time is plausible. For children, this includes time spent walking and running, playing games and other activities where their peers are on their feet.
Proper assessment includes measuring range of motion and muscle strength, especially in the hips, knees and ankles. The ability to obtain a somewhat neutral alignment is necessary to achieve proper weight-bearing through the long bones, as well as prevent joint compromise. Accessing head control is important, since the neck muscles can weaken as DMD/BMD progresses.
Head and upper-body control may also dictate the type and configuration of stander. Orthotics, individualized accessories or additional restraints may be necessary to achieve an appropriate degree of upright posture. In general, achieving a posture where the body is cantilevered to at least 70 degrees or greater to the horizontal is likely optimal. Documenting respiratory and cardiac function in sitting, as well as any gastrointestinal function at baseline, is important for justification of the effectiveness of a standing program.
Consider Transfers Also
Prescribing a stander does not end with the patient's physical needs. The method of transferring to and from the device should be considered. Safe transfers that provide the user with as much independence as possible is paramount to consistent usage. For larger users, it may be impractical to transfer to a fully reclined stander in a prone or supine configuration, achieve proper alignment and move to upright.
For individuals with DMD/BMD, a sit-to-stand stander may be the most practical. The stander itself should fit into the user's physical environment, be it home or school, and also his lifestyle. A proper evaluation likely includes a trial with one or more standers in the environment where they are intended. Sometimes, instruction for a few sessions in the clinic is required prior to an off-site trial. Goals for the trial period should be established that identify the feasibility of the standing program and some identifiable benefit.
Documenting changes in mood or effect may indicate the likely success of a standing program. The evaluation of the need for and procurement of a stander should conclude with a long-term program for use, including frequency and duration, activities and desired outcomes. Most importantly, the standing program must strike a balance between providing maximum upright positioning for a clinically significant time and decreasing the stresses placed upon the user and caregiver in implementing its use.
Donovan began exhibiting increased difficulty with walking around nine years of age. By age 10, he was unable to walk independently, and showed difficulty bearing weight through his legs to transfer. Functionally, it was clear that Donovan would require assistance to stand. However, Donovan continued to demonstrate sufficient upper-body strength and core stability to perform transfers with the assistance of a sliding board and very little help from a caregiver. Given his history of toe walking, Donovan demonstrated contractures in the ankle plantarflexors, which also limited knee extension. Most importantly, Donovan was unable to interact with family and friends in an upright position, limiting his choices of participation.
Donovan's evaluation included a one-week trial with a sit-to-stand stander. This was selected due to his continued success with sliding-board transfers and to promote independence with the standing program. Options also existed to compensate for his contractures.
Donovan kept a log of his trial period, documenting the time spent standing each day, and noting any positive effects. Donovan also kept track of barriers to using the stander, which helped the PT identify both strategies for success and accessories to improve stander use. Donovan himself identified that moving slowly to a fully upright position lessened any discomfort associated with the increased stretch felt in his legs. Donovan's family was able to experience the stander in their home, and identified strategies for incorporating the stander into daily activities. The trial period provided a practical illustration of the stander's footprint and function.
Donovan's PT composed a letter of medical necessity fully outlining Donovan's needs and the positive effects of standing. A physical medicine and rehabilitation provider reviewed the letter and provided a prescription for the equipment. A durable medical equipment vendor worked with Donovan's family and their insurance provider to order and deliver the stander, and ensured proper fit upon delivery. Donovan's care team reviewed his use of the stander, and encouraged increasing the frequency and duration of use. The entire process took six months to evaluate and implement a home program with Donovan's new stander.
Today, Donovan uses his stander at least five days per week. He stands for up to one-and-a-half hours per day, taking short breaks when needed. "Sometimes I play video games, eat dinner, watch movies or just hang out while I'm using it," explains Donovan.
During the school year, Donovan does homework while standing, and enjoys talking with his family and friends at eye level. His stander is equipped with casters, so Donovan's family can move it within their home, allowing him to participate in various activities. Donovan and his family have found that adding any equipment or changing a routine is hard, and sometimes it is difficult to maintain a home program.
Focusing on the benefits can help. "To me, it feels like blood is reaching my legs better," describes Donovan. While standing, he can also exercise his arms to keep strong for one of his favorite activities, floor hockey with his power wheelchair.
There are no known cures for the underlying myopathy associated with muscular dystrophy. But supportive therapies can reduce deleterious effects and improve quality of life. A stander should be part of a global management plan for treating DMD/BMD. While the positive benefits are identifiable, more research into the mechanism of effect would increase understanding and support reimbursement, allowing more children to access and benefit from these devices, as Donovan has.
"Being in my stander feels really good," concluded Donovan. "It helps stretch out my muscles and puts weight on my feet. I know it's good for my body."
Jason M. Kelecic is program manager, Gillette Children's Specialty Healthcare Center for Pediatric Neurosciences Neuromuscular Program in St. Paul, MN.