Prof. Dr. A. Ayşe Karaduman
H.U. Faculty of Heath Sciences Department of Physiotherapy and Rehabilitation
Spinal muscular atrophy (SMA) is a common disease name assigned to a group congenital neuromuscular (affecting nerves and muscles) disorders. The disease emerges as a result of injury to some spinal cord cells responsible for muscle contractions, rendering them unable to perform their tasks. These cells are responsible for transmitting the orders coming from the brain to the muscles. The muscles wherein the order of motion did not arrive cannot contract and weaken gradually. All of the arm and leg muscles, together with truncal and some of the respiratory muscles become affected from this disease.
Four types of SMA disease are defined, each characterized with distinct clinical type and severity. On the basis of the motion ability and functional status, they are subdivided as follows:
Type 1 SMA: They are unable to sit independently, and their head control is quite poor.
Type 2 SMA: Head control is achieved and they can sit. However, they are unable to assume sitting position when lying.
Type 3 SMA: They can stand and walk.
Type 4 SMA: This is the type which is seen in the adult. There is weakness in the arms and muscles. Generally, these patients are able to walk.
Spinal muscular atrophies are congenital diseases, and they are not contagious. Genetic defects are observed in the congenital diseases. The genes cause the production of some proteins, rendering the cells functional. When genetic defects are present, these proteins cannot be produced properly; moreover, they are likely to be produced less or more than needed. At this point, some injuries may ensue in the relevant cells. Since the anterior horn cells are rendered dysfunctional in SMA, the bodily muscles that act voluntarily suffer from weakness and atrophy.
The genetic defect bringing about SMA is known. Therefore, the diagnosis can possibly be established during pregnancy period in the presence of the disease in the family. Carrier state, moreover, can also be identified.
The aim of the rehabilitation in patients with SMA is to prevent joint deformities, to protect the muscle, to deal with the respiratory complication, and to help the patients sustain their social living and roles in the life. Success in rehabilitation is only possible through implementation of patient-specific specialized programs.
The first phase in the rehabilitation of the patients with SMA comprises evaluation of the existing physical status of the patient. Furthermore, the evaluation should be repeated every three or six months, since the functional status of the children is influenced by the growth factor. Widespread weakness in the muscles despite growth exerts negative impact not only on the bones but also on the tendons, resulting ultimately in developmental disorders in the bones. Underdeveloped hip joint can serve as an example. Bilateral hip dislocation is a condition which is frequently seen in the cases with SMA.
The joints are quite loose in children with SMA. The joint motion range can even exceed what was expected in the early periods, which stands for an exacerbating factor in scoliosis. Primary factors that affect the functional status of SMA patients are as follows:
There is retardation in the physical development of the children with SMA type 1 and 2. One of the most crucial problems in SMA cases is the formation of curvature in the backbone, which is also called scoliosis. Occurrence of scoliosis is rather fast in especially those SMA cases who are unable to walk.
Deformities in the arms and legs also are most frequently seen in non-ambulatory cases. Such deformities generally manifest as twists in the leg, hip, knee and ankle joints. Deformities in the arms are more seldom, with the elbow joint most frequently affected.
Basic application is utilized during the rehabilitation of SMA cases.
Positioning: Bad sitting posture, incorrect hugging and carrying accelerate joint deformations. Taking into consideration the other factors, appropriate body postures where the backbone, arms and the legs are not twisted are thought to the family. The physiotherapists can guide the families in this regard.
Exercise Applications: Exercises applied taking into account the degree of muscular weakness, effect of disease severity on the joint, and general heath and growth status of the child are important to protect and strengthen the muscles and to prevent deformations. The exercise should not be applied randomly, rather should be sustained under strict controls and supervision of the doctor and the physiotherapist. Incorrect applications may prove harmful.
Strengthening of the arms is important for personal care and maintenance of daily living activities. SMA cases are subjected to weakness by 40-50% in the arm muscles.
The twisting type deformities encountered in the elbow joint have generally nothing to do with functional problems in children, whereas those deformities observed in the legs follow almost always a progressive course. Thereby, exercise applications are of paramount importance for bodily positions.
Devise (Orthotics) Applications: Orthotics are assist devices applied to the trunk or the extremities in order to prevent and delay deformations, and to maintain and improve joint functions. Besides the orthotics applied to slow the development of scoliosis and to maintain the sitting position, walking orthotics are also widely utilized to achieve standing and walking in SMA. However, specific criteria are required to use these orthotics, and each case should be assessed individually.
Respiration Physiotherapy: Weakness of the respiratory muscles decreases the ventilation of the lungs in SMA patients, which in turn leads to the generation of pulmonary dysfunctions and diseases.
Muscles related to coughing may become weakened, hindering disposal of the sputum. The risk of physical obstruction of the airway by food particles becomes quite high in patients with generalized muscle weakness. Sustaining the head in the upright position and chin support are paramount especially during ingestion of small food particles, pipette use and feeding. Frequent feeding, less amount each time, is more appropriate.
The changes in the soft tissues and joint deformations attributable to immobility are almost always progressive and affect the respiratory functions, thus increasing the risk of respiratory infections. It is important from the early periods on to improve the muscle strength, to sustain the flexibility of the chest wall, to increase the motion range, and to improve the physical functioning. Appropriate positioning is also of great importance for the respiration. The physiotherapists recommend such positions that are both appropriate and act in favor of respiratory relaxation. The positions wherein the gravitation force helps are generally more appropriate. Using a carrying strap eases assuming the positioning. Positioning, together with various drainage methods, proves useful during disposal of the lung secretions (sputum). Appropriate postural drainage and aspiration methods can be taught to the families to apply. Constipation is a frequent complication in children with SMA. In such circumstances, regulating the feeding and massage to the abdominal area may help alleviate this problem.