A 4-year-old male with spinal muscular atrophy (SMA) presents for vertical expandable prosthetic titanium rib (VEPTR) insertion. He was diagnosed with SMA at 8 months of age. He has gastroesophageal reflux and is fed via a gastrojejunostomy tube. He is wheelchair bound and is dependent on biphasic positive airway pressure (BiPAP). He has reactive airways and is on fluticasone and albuterol.
The physical examination shows a smiling child with obvious scoliosis sitting in a wheelchair. He is verbally communicative but speaks softly in a whispered voice. Venous access is poor.
Spinal muscular atrophy is an autosomal recessive disorder that is associated with the death of anterior spinal horn motor neurons. There are several forms of the disease:
Type 1 SMA is a severe form of the disease that manifests during early infancy. Without significant respiratory support, these children will rarely survive beyond infancy or childhood. The most severe form of this disease is often called SMA0. Children with SMA0 rarely survive to adolescence; those with mild forms of SMA1 who receive contemporary excellent, aggressive care, have survived to adulthood.
Type 2 SMA disease patients are moderately affected; presentation is between 6 and 18 months of age. Many children survive to adulthood.
Type 3 SMA patients have a near normal life expectancy.
Type 4 SMA or adult-onset disease manifests in the third decade of life with increasing proximal muscular weakness but near normal life expectancy.
Signs and symptoms can include floppiness early in infancy in the most severely affected; weakness of the appendicular and axial musculature, resulting in a weak cough and cry; poor feeding; failure to thrive; delay in the development of motor milestones; respiratory distress; aspiration pneumonias; areflexia and fasciculations (especially of the tongue). These patients may require noninvasive forms of ventilation such as continuous positive airway pressure, BiPAP, and cough assist devices; in some cases, tracheostomy is required for ventilation or pulmonary toilet. In addition, because of bulbar involvement, feeding may be best accomplished by a gastrostomy tube or gastrojejunostomy. Some children require a fundoplication to prevent aspiration of gastric contents. The development of kyphoscoliosis often requires surgical intervention in the form of fusion or spinal instrumentation to allow patients to sit comfortably and avoid progression of their restrictive pulmonary disease. These patients may have abnormalities of fatty acid oxidation and tend to develop metabolic acidosis during prolonged fasts. Arrhythmias, congenital structural cardiac disease, and decreased myocardial function have been reported in these patients.
VEPTR is a telescoping rod that is applied to the concave side of the deformity; it is designed to prevent the progression of thoracic insufficiency syndrome and theoretically allows for normal chest and consequent lung growth. Unlike spinal fusion and instrumentation, these devices can be expanded intermittently to allow for growth, and the application procedure itself is less invasive and has less potential for ...