Spinal Muscular Atrophy Orthopedic Care
Overview of Orthopedic Care and Rehabilitation Strategies in Spinal Muscular Atrophy
Muscle weakness of varying severity limits motor function of trunk and upper and lower extremities, resulting in contracture formation, spinal deformity, limited mobility and activities of daily living, and increased risk of pain, osteopenia, and fractures.
Key Evaluation Procedures
These include evaluating range of motion, strength, function, seating and mobility, orthotics, radiographs (spine and other joints), and dual energy x-ray absorptiometry. The value of these procedures varies by degree of functional impairment.
In nonsitters, nutritional support, posture management, seating, contracture and pain management, therapy for activities of daily living and assistive equipment, wheelchairs for mobility, limb orthotics, and developmental therapies are important. In sitters, wheelchair mobility, contracture management, physical therapy, and occupational therapy are of highest value, with strong considerations for spine and limb orthotics and spine surgery. In walkers, the highest emphasis is on provision of physical therapy, occupational therapy, and wheelchair/mobility, although orthotics, scoliosis surgery, and pain management figured prominently. In the United Kingdom and some other European countries, chest physiotherapy is often done by physical therapists.
Arm and Leg Weakness
Written for FightSMA by Robert T. Leshner, M.D., Professor, Neurology and Pediatrics, Children’s National Medical Center
Progressive weakness and immobility of the arms and
legs in spinal muscular atrophy patients may predispose to other orthopedic problems including tightness of the joints (contractures). Physical therapists can instruct children and their families in range of motion techniques to help prevent these problems. Night splints of the ankles and wrist may also be useful in preventing contractures. Facilitated independent sitting or standing with a special chair or a standing frame may be an important part of the child’s daily therapy program.
Rehabilitation and Orthopedic Problems in Spinal Muscular Atrophy
Literature review pertinent to these rehabilitation and orthopedic concerns reflects similar musculoskeletal and functional problems to those presented in “Key Problems”. Hip subluxation is a common comorbidity in patients with spinal muscular atrophy. As patients with spinal muscular atrophy age, there is a significantly higher prevalence of kyphoscoliosis, difficulty coughing, joint contractures, and voice/speech problems in types 1 and 2. In type 3, there is also a significantly higher prevalence of fatigue and hypermobility of the hand. Scoliosis develops in more than 50% of children with spinal muscular atrophy, most commonly in nonambulatory children or in those who lose the ability to walk.
Traditional measurements of strength are not possible in severely affected infants and children; thus, emphasis is on observation of function. Evaluation procedures that address rehabilitation/orthopedic concerns include the CHOP-INTEND, the Hammersmith Functional Motor Scale for Spinal Muscular Atrophy, the Modified Hammersmith Functional Motor Scale for Spinal Muscular Atrophy, the Gross Motor Function Measure, and the Motor Function Measurement scale for neuromuscular disease. Most children with spinal muscular atrophy require help or supervision with bathing and dressing and assistance with mobility. Stairs present a major obstacle. Early and generalized joint contractures and scoliosis correlate with level of motor function and walking with support, rolling by 5 years of age correlates with eventual walking, and inability to roll correlates with severe disease (greater weakness). Muscle strength can be quantified using myometers, videotaped movements, handheld dynamometers, and quantitative muscle testing in children with the type 2 or 3 forms of the disease. Flexion contractures, which affect almost half of spinal muscular atrophy patients, are often noted during periods of inactivity and are considered intractable if greater than 45Â° Activities of daily living are hampered, and contractures are perceived to be associated with disability in about half. Pain increases in frequency and severity over time and correlates with decreased scores on quality-of-life indicators. In all studies of scoliosis, spine radiographs were routinely used for diagnosis. A retrospective review of spinal full-length radiographs revealed a predominance of right-sided thoracic and thoracolumbar curves and leftsided lumbar curves.
No studies directly address physical therapy and occupational therapy as general therapies, although a case report documented the ability of a 20-month-old girl with spinal muscular atrophy to learn to operate a power wheelchair independently in 6 weeks and demonstrated developmental gains in all domains of the Batelle Developmental Inventory over the ensuing 6 months. Regarding other interventions, 3 case series discussed the use of knee-ankle- foot orthoses in patients with spinal muscular atrophy. Evans presented 5 cases (3 who had lost the ability to walk) who were treated with serial casting and bracing and were still ambulatory 2 to 5 years later. Granata presented 7 cases and later 12 cases of patients with type 2 spinal muscular atrophy. All were able to stand independently with knee-ankle-foot orthoses, and 7 achieved assisted ambulation. When compared with a historical control group, the treatment group had less scoliosis. There may have been a trend toward greater hip subluxation in the treatment group.
Consensus Recommendations on Evaluation and Treatment by Functional Levels
The natural history of the disorder should be considered along with the results of the examination and the goals of the patient and family in planning treatment. Intervention should address the problems that were identified through a thorough history and examination. On the basis of the literature review, the results of the Delphi survey, and our group conferences, we list recommendations in this care area by the functional levels of these patients.
These patients present in early infancy to rehabilitation providers with impairments in respiratory function and profound weakness. Limited range of motion, head control, postural control and alignment, and progressive scoliosis are found. There is significant fatigue during and after medical care and with therapies. Weakness leads to varying functional deficits that interfere with caretakers’ abilities to perform activities of daily living and that also limit participation in developmental activities and later in school. A multidisciplinary approach to evaluation and management includes a strong partnership between therapists, patients and families, and physicians. Assessments include physical and occupational therapy and speech therapy if swallowing is impaired or if speech production is affected by jaw contractures and inadequate ventilatory support of voice. Play and occupational support should include lightweight toys and assistive technology with variable controls and a myriad of activation systems. Consideration of the patient’s primary posture should direct choice of equipment and devices that support function. Upper extremity orthotics to aid in function include the use of mobile arm supports or slings that augment active range of motion and functional abilities. Use of linear elastic elements to balance out the effects of gravity in multiple dimensions can aid those with proximal weakness and improve control of distal function. Upper extremity or hand orthoses should be considered with caution because attempts to correct postural deviations and compensations with an orthosis may result in reduced function. Compensations due to hypermobility and lack of power should not always be discouraged. Splinting to preserve range of motion and prevent pain may be indicated.
Weakness, contractures, respiratory dysfunction, and scoliosis characterize the main problems of this group. These impairments contribute to limitations in mobility, endurance, and activities of daily living. Evaluations by physical therapists, occupational therapists, and orthopedic surgeons include measurement of contractures and strength by goniometry, manual muscle testing, or myometry, with judicious use of spine and hip radiographs. Equipment evaluation includes seating and mobility, positioning, and equipment for self-care. The need for assistive technology and adaptive aids should be determined in the context of improved function. Pulmonary evaluation should be conducted, as it pertains to exercise tolerance and endurance. Evaluations for manual and power mobility may be conducted as early as 18 to 24 months of age. Contracture management and exercise are a major focus of treatment, with implementation of a regular stretching and bracing program to preserve flexibility. Serial casting for contractures may improve participation in a standing program and improve tolerance of bracing. Regular exercise should be encouraged to maintain fitness and endurance and might include swimming and adaptive sports. Lightweight ischial weight-bearing knee-ankle-foot orthoses or reciprocal gait orthoses should be considered for standing or assisted ambulation with a walker for patients with sufficient strength. Where this is not possible, a standing frame or mobile stander with ankle-foot orthoses should be considered. Upper extremity orthotics with mobile arm supports or slings augment active range of motion and functional abilities. Assistive technology and other adaptive equipment to enhance independent work and play should be considered.
The combination of proximal weakness and impaired balance results in frequent falls. Limitations are found in transitions between the floor, sitting and standing, distance ambulation, changes in terrain, and stair climbing. There are consistent complaints of fatigue with activity. Musculoskeletal deformities and pain are most commonly reported in late childhood and early adolescence, and with their onset, functional limitations become more pronounced. Patients may present acutely for management of fractures or other musculoskeletal injury. Balance and ambulation evaluations include a specific survey of environmental adaptability and access. Evaluation of joint range of motion and spinal alignment as they affect function, comfort, and balance guides more specific orthotic and spinal assessment and x-rays. Physical and occupational therapy assessments to determine appropriate mobility aids, adaptive equipment, assistive technology, and environmental access will allow patients to maintain independence and mobility and to conserve energy. Activities of daily living assessment for equipment and adaptation may improve independence and access to home and community environment. Nonspine x-rays and dual energy x-ray absorptiometry are considered in the event of acute musculoskeletal injuries as a result of overuse, an accident, or a fall. Treatment and interventions should consider goals of the family and/or caretakers and should be problem-driven. Physical therapy consultation helps to maximize safety, endurance, and independence or to prolong ambulation. Orthotics also support functional walking. Wheelchair mobility for longer distance transportation adds mobility and independence. Walkers appear less likely to develop scoliosis; thus, continued walking should be encouraged. Contracture management and education to maximize joint protection should be a part of any treatment program. Maximum functional activity includes access to leisure, adaptive sport, and play activities. Regular exercise to maintain fitness and stamina should be encouraged and may include swimming, aquatic therapy, horseback riding, and adaptive sports. Weight management with attention to fitness and education about nutrition are necessary. Equipment needs related to activities of daily living and assistive technology and other adaptive equipment may be useful to enhance abilities for independent work and play. Environmental controls and home modifications to allow for safe accessibility and optimal independence should be explored. Driver’s education alternatives and consideration of customized driving controls should be part of the overall rehabilitation management of the adult with spinal muscular atrophy.
In selecting and fabricating an orthosis for patients with spinal muscular atrophy, it is important that the orthotist, therapist, and family work together to ensure that the appropriate orthosis is fabricated and allows wearers to meet their functional goal. For patients with spinal muscular atrophy, it is particularly important that the orthotist has a good background and experience in working with patients with neuromuscular disorders. Familiarity with patterns of weakness and compensations allows the orthotist to choose proper materials and to make adaptations that allow for “best” fit and function. Spinal orthoses may be used for postural support, but there is insufficient evidence to support delayed curve progression. When used, spinal orthoses should be fabricated with an abdominal cutout to allow appropriate diaphragmatic excursion and access to gastrostomy tubes where present.
Surgical correction of scoliosis should be considered based on the patient’s curve progression, pulmonary function, and bony maturity. Scoliosis surgery in children with prolonged survival provides benefits in sitting balance, endurance, and cosmesis. Evidence suggests that earlier surgery results in better outcome. Beneficial effects on pulmonary function remain controversial, but the rate of pulmonary decline may be slowed. Intraoperatively, excessive bleeding may occur. Postoperatively, complications include loss of correction, pseudarthrosis, a requirement for prolonged ventilatory support, and chest and wound infections. Careful consideration is warranted for the spinal muscular atrophy patient who is still ambulatory because altered function, balance, and respiration may result in loss of independent walking. Pelvic obliquity may require surgical fixation. Intraoperative neurophysiologic monitoring may detect temporary abnormalities during scoliosis surgery. A survey of patient/parent satisfaction and clinical/functional outcome was sent to 21 patients with spinal muscular atrophy who underwent operations for scoliosis. Of those who returned the surveys, all found benefit from scoliosis surgery regarding cosmesis, quality of life, and overall satisfaction. Although there is a higher rate of hip subluxation in spinal muscular atrophy, few are painful. Surgical reduction and osteotomy are frequently followed by redislocation. In most circumstances, this surgery is avoidable. Ankle and foot deformities make conventional shoes difficult to wear, and orthopedic surgeons may consider soft tissue releases at the child and family’s request. In walkers, if soft tissue releases are performed, rapid and aggressive physical therapy may improve outcome.
Perioperative Management in Spinal Muscular Atrophy
Perioperative management and the role of rehabilitation should be customized according to the specifications and needs of the patient and family, therapist, and surgeon. In general, preoperative management includes appropriate modification of the individual’s environment, a plan for orthotic intervention, and confirmation of timing and modification of orthoses. New wheelchairs or wheelchair modifications of the seat, back, arm, leg, or headrests are likely to be required. One may anticipate increased sitting height after scoliosis surgery, resulting in the need for van modifications. Families need instruction in transfers, including arrangements for a mechanical lift, if necessary. Arrangements for bathing, toileting, and dressing equipment and potential modifications to clothes for ease in donning and doffing over, under, and/or around casts or orthoses are necessary. Two small studies found that noninvasive positive pressure ventilation, 1 with mechanical-assisted cough training prior to surgery, resulted in successful extubation. Incentive spirometry practice may be initiated and coordinated with preoperative noninvasive pulmonary supports, such as bilevel positive airway pressure and exsufflator (cough-assist) devices. Postoperatively, one must confirm timing of appropriate casting and fitting of orthoses, allowed range of motion, and activity and that appropriate adaptive equipment is available. Therapists can ensure appropriate use of incentive spirometry and instruction of nursing staff and family on bed mobility, transfers, dressing, bathing, and toileting. The individual should be mobilized as soon as possible, as allowed by the procedure and surgeon.
Infants and children with spinal muscular atrophy should have appropriate evaluation for their presenting musculoskeletal and functional deficits. Goals of therapy and surgery depend on functional level and the family’s wishes. Even young children should be offered independent mobility and activities of daily living, which includes play. Whenever possible, walking should be encouraged with appropriate assistive devices and orthotics. Hip subluxation is rarely painful, and there is a high risk of recurrence despite surgical correction. Spinal orthoses may provide postural support but do not prevent curve progression and may impair respiratory effort. Scoliosis surgery appears to benefit patients who survive beyond 2 years of age when curves are severe and progressive and should be performed while pulmonary function is adequate. Preliminary studies show the benefit of preoperative training with noninvasive ventilation and cough-assist devices. Intraoperative neurophysiologic monitoring detects early neurologic compromise in some and may improve outcome.
Written for FightSMA by Robert T. Leshner, M.D., Professor, Neurology and Pediatrics, Children’s National Medical Center
Children with Type I and Type II Spinal Muscular Atrophy virtually never achieve independent standing or walking. Their independent mobility invariably requires wheelchair assistance, Because most children lack the upper body strength to propel a manual wheelchair, a power chair is the logical choice. Many youngsters can be taught to safely operate a power chair when they are only two or three years of age! This enables them to participate in household and outdoor activities with their family and peers.