Mehta Casting for Early-Onset Scoliosis: Early and Often Work Best, but May Sometimes Be Overtreatment

Commentary Children have greatly benefited from the tremendous twenty-first century progress in the treatment of early-onset scoliosis. From classification and evaluation, to understanding the natural history, to novel implants and surgical techniques, our progress with early-onset scoliosis has far exceeded that with other aspects of spine deformity treatment. Young lives are now saved (or extended) thanks to the collaborative research and many innovations in treatment for these rare conditions in the past 25 years. On this journey, we have learned many lessons, such as the importance of early spine growth and protecting or creating space for lung growth. The days of fusing most of the thoracic and lumbar spine for severe deformities in toddlers are long gone. However, perhaps the most important lesson that we have learned is the high complication rate and negative consequences of treating early-onset scoliosis with spinal instrumentation at an early age. Those of us with decades of experience treating early-onset scoliosis have battled the complications of fixation failure, infection, and spine autofusion when we start instrumentation while the patients are young and do repetitive surgery. We know that we must delay initial instrumentation as long as possible. Fortunately, in addition to novel instrumentation, Mehta’s casting technique has been added to the treatment arsenal at early-onset scoliosis centers around the world1,2. Scientific study of the efficacy of Mehta casting has been limited by numbers; early-onset scoliosis is rare, and results vary greatly on the basis of the underlying diagnosis, the initial curve magnitude and age, and the casting technique. For this reason, the study by Fedorak et al. is an extremely valuable contribution to our literature. The authors had large numbers of children with idiopathic early-onset scoliosis, they used a consistent technique, and they had excellent age stratification and good follow-up. Their results show dramatically better rates of “cure” (final curve of <15°) when casting was begun before a child was 18 months old. It is clear that the better we become at early identification and treatment of idiopathic early-onset scoliosis, the greater chance we have of obtaining a “cure.” Although Fedorak et al. present strong evidence for initiating Mehta casting before the patient is 18 months of age, some perspective and caution are essential: we risk overtreatment. Infantile idiopathic scoliosis can resolve spontaneously. Some of the babies who underwent casting by Mehta were as young as 6 months old and had scoliosis as small as 11°. Simple observation might have led to a “cure” in many. In the study by Fedorak et al., the mean number of casts was 8, with an interquartile range of 5 to 10; that is a lot of anesthesia given to the infant or toddler brain. Several very concerning preclinical studies documented the impact of anesthetic drugs on the developing mammalian brain. In 20173, the U.S. Food & Drug Administration (FDA) issued a warning stating “exposure to these medicines for lengthy periods of time or over multiple surgeries or procedures may negatively affect brain development in children younger than 3 years” and “consideration should be given to delaying potentially elective surgery in young children where medically appropriate.” Infant and toddler general anesthesia followed by application of a corrective cast by a surgeon, repeated every 8 weeks, is also a very expensive treatment strategy. Finally, our ability to effectively treat scoliosis with bracing has advanced considerably in the twenty-first century. Bracing fabrication technology is much better, and we have very effective compliance monitoring devices for braces that allow the treatment team to determine if the deformity is persisting or worsening despite good brace compliance. Based on all of these considerations, consider a clinical scenario: an otherwise healthy 10-month-old infant presents with 25° of scoliosis first noticed last week. Should that baby go straight to the operating room for anesthesia and a Mehta cast? Alternatively, another radiograph could be made 2 months later. If the scoliosis is resolving, then close follow-up is continued. If the scoliosis is persistent or increasing, a trial of bracing is initiated for 4 months. As many of us have observed in our practices, bracing alone can yield a “cure.”4 If scoliosis persists or increases, then Mehta casting is begun (perhaps without anesthesia)5. Idiopathic early-onset scoliosis treatment following this stepwise plan can be highly effective, excessive anesthetics and health-care expenses can be limited, and the family and care team will know that the baby was not overtreated.