Lonstein and Carlson, 1984, is a popular resource on the topic of scoliosis progression. Their study features a progression factor equation taking a child’s age, Cobb angle and Risser sign (method of estimating skeletal maturity) into account to estimate percentage risk of scoliosis progression. Their conclusions are not without limitations but at least offer a somewhat quantifiable method of assessing progression risk for young adolescents, 29º degrees and under, with scoliosis.
Lonstein and Carlson concluded that kids 10 or younger, with curves under 20º, have about a 45% chance of curve progression. For curves with Cobb angles in the range of 20º to 29º, progression risk increases dramatically. No conclusions on kids with curves over 29º degrees were reported. However, it is generally accepted that curves of greater severity are at higher risk of progression when there is remaining growth. In the Lonstein and Carlson study, for older teens, the risk of progression is reduced when curves were detected under 29º, but when growth remains, there is still the risk of progression.
Researchers now concur that curve severity at initial presentation is a critical factor for predicting scoliosis progression. Growth velocity, curve pattern, gender and vertebral rotation should also be considered. Family history and spinal flexibility may also factor.
Some of the creators of Scoliscore (a test that was claimed to be, but turned out not to be a highly accurate predictor of scoliosis progression) reported that Lonstein and Carlson’s results are unrepeatable. The Scoliscore test was based on a saliva sample of a patient with scoliosis. However, there were several limitations to Scolioscore including issues with accuracy for races other than Caucasians. A 2014 study claimed, “the risk of progression based on ScoliScore differed very significantly between our study population and the initial validation group that ScoliScore published,” according to Dr. Brnjamin Roye. The company that created Scolioscore, Axial Biotech (owned by a group of spine surgeons and geneticists) sold Scoliscore in 2015 for 4.4 million. Axial Biotech is no longer in existence.
What parents should understand is that estimation of progression is just that, a guesstimate. Physicians still rely on their clinical experience. Today, there is really no conclusive method of determining who will progress, and/or to what degree. For this reason, scoliosis should be monitored very closely in adolescence.
Lonstein JE & Carlson JM. The predication of curve progression in untreated IS during growth. J Bone and Jt Surg 66-A. 1207-1221.
Hana Kim, Hak Sun Kim, Eun Su Moon, Choon-Sik Yoon, Tae-Sub Chung, Ho-Taek Song, Jin-Suck Suh, Young Han Lee, Sungjun Kim. Scoliosis imaging: what radiologists should know. Radiographics. 2010 November; 30(7): 1823–1842.
Van Goethem J, Van Campenthout A. Scoliosis. In: , van Goethem J, van den Hauwe L, Parizel PM, eds. Spinal imaging: diagnostic imaging of the spine and spinal cord. Heidelberg, Germany: Springer, 2007;95–108.