Casting for Treatment of Early-Onset Scoliosis—Practice Pearls

“Big curves in little people are an enormous problem,” said Peter F. Sturm, MD, MBA, in a webinar on casting for treatment of early-onset scoliosis held by the Scoliosis Research Society in October 2017. “Severe curves affect the space available for the lung and alveolar growth over time,” said Dr. Sturm, who is the Alvin H. Crawford Chair of Spine Surgery and Director of Crawford Spine Center at the Cincinnati Children’s Hospital Medical Center in Ohio.

The goals of casting are to control the scoliosis curve, promote growth, maintain adequate pulmonary function, and prevent the need for early fusion, which can result in thoracic insufficiency syndrome, explained Co-Chair of the webinar James O. Sanders, MD, Professor of Orthopaedics and Pediatrics at the University of Rochester and Golisano Children’s Hospital in Rochester, NY.

EDF (elongation, derotation, flexion) casting was initially developed for use in adults and was adapted for use in infantile and early-onset scoliosis by Min H. Mehta, FRCS.1
Pediatrician checks a little girl with a stethoscope while her mother holds her. “Casting in non-idiopathic scoliosis may achieve a significant improvement and delay surgery"Younger Age, Smaller Scoliosis Curves are Best for Casting
A landmark study by Mehta et al indicated that the best results from casting are found in children with idiopathic scoliosis who are younger and have less severe Cobb angles, Dr. Sturm said.1,2 Similar findings were reported by Dr. Sanders and colleagues in a study of 55 patients with progressive early-onset scoliosis treated with casting. Scoliosis curvature decreased in 49 patients (89%), and 6 patients (11%) eventually underwent surgery because of worsening curve.2 Full correction was most often found in patients <20 months of age, and with Cobb angles <60 degrees.2

The only other factor that appears predictive of outcome is the degree of scoliosis correction in initial cast correction, Dr. Sturm noted.3 “Correction of more than 50% in the initial cast seems to be consistent with cast success,” Dr. Sturm said.

However, casting should not be considered a failure in patients with more severe curves, if the treatment prevents the curve from progressing and delays the need for surgery, the faculty said.

In patients with congenital scoliosis, casting can be used as a delay tactic and was found to successfully delay surgery by 2 years in a study by Demirkiran et al—even though no real correction in curves occurred, said Charles E. Johnston, MD. Dr. Johnston is Assistant Chief of Staff at Scottish Texas Rite Hospital for Children, and Professor in the Department of Orthopaedic Surgery at the University of Texas, Southwestern Medical Center in Dallas.4

“Casting in non-idiopathic scoliosis may achieve a significant improvement and delay surgery if the patient achieves about 30% correction,” Dr. Johnston said. “For older patients who don't achieve any correction, this technique is only useful as a delaying tactic.”

The Benefits of Delaying Surgery for Early-Onset Scoliosis
There are many reasons to delay surgery in early-onset scoliosis. Early fusion can result in iatrogenic thoracic insufficiency syndrome because it impairs the growth of the thorax, spine, and intrathoracic contents, Dr. Johnston explained. In addition, a greater number of lengthenings used in growth-sparing technique increases the risk for premature ankylosis and complications, including infection, he said.

“Growth-sparing techniques can unintentionally actually end up causing the same sort of problem as early fusion,” Dr. Johnston noted.

In a study by Dr. Johnston and colleagues comparing casting as a delay tactic to growing rod instrumentation, no difference in absolute spine length at follow-up was found in children with idiopathic or syndromic scoliosis.5 The complication rate was markedly higher with growing rod instrumentation (44%) than with casting (1%). A total of 15 of the 27 casted patients eventually underwent surgery after a mean delay of 1.7 years after casting.

When used as a delaying tactic, “casting is not detrimental to the eventual spine growth in this group of patients,” Dr. Johnston emphasized.

“If you can’t improve the curve, but you hold it and avoid earlier surgery, we are certainly doing something positive in these kids,” Dr. Sturm agreed.

“Keep in mind, however, that any delaying tactics must not be detrimental to deformity control or spine and thoracic growth, or else it is not a valuable technique,” Dr. Johnston said. In addition, “a potential disadvantage of delaying surgery is that by starting later you may miss a window of what is considered to be the best time to stimulate alveolar growth; however, this has not been proven in human studies,” Dr. Johnston said. Also, delaying surgery “may require more complex procedures secondary to more deformity if the delaying tactic” is not effective.

Practice Pearls
“Remember that the correction is rotational and not lateral pressure because this can deform the ribs, and we want to mold the cast both for rotation as well as controlling the pectoral area,” Dr. Johnston said.

“A larger curve (>53 degrees) will be more efficiently corrected by traction, and a smaller curve (<53 degrees) will be more efficiently corrected by transverse loading,” Dr. Johnston said. “By combining these two, we should be able to accomplish our most efficient biomechanical correction.”

When asked about the frequency of cast changes, the speakers suggest using the following protocol: every 2 months for two-year-olds, every 3 months for 3-year-olds, and every 4 months for 4-year-olds.

“Clearly, you need to have some flexibility based upon how fast the individual child is growing, but that protocol seems to work well,” Dr. Sanders said. Dr. Johnston noted that casting should be stopped if the patient develops chest wall deformity (eg, rib sloping).

While there is no specific cutoff for the upper limit of casting, Dr. Johnston suggested that the upper limit is a child who is too large or stiff for casting and would require “an excessive amount of molding force, which is not going to be tolerated well either by the child or by the family because of complaints of discomfort and difficulty with sleeping and activities of daily living.”

Furthermore, the faculty noted that decubiti is a potential problem in young children and recommend using silver impregnated T-shirts, Knit-Rite shirts, or Boston brace T-shirts to protect the skin from any small objects that may fall into the cast.

Disclosures
Charles E. Johnston, MD, disclosed relationships with Medtronic (other financial or material support [royalties, patents, etc]) and Elsevier (other financial or material support [royalties, patents, etc]).

James O. Sanders, MD, disclosed relationships with Green Sun Medical (advisory board or panel [industry]) and NuVasive (speaker’s bureau).

Peter F. Sturm, MD, disclosed relationships with DePuy Synthes (consultant, advisory board or panel [industry]) and NuVasive (consultant).

Updated on: 11/03/17
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