Lonstein & 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 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 & 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. For older teens, the risk of progression is reduced when curves were detected under 29º, but when growth remains, there is still 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 have reported Lonstein & Carlson’s results are unrepeatable. Scoliscore is a diagnostic predictor based on a saliva test to determine risk of progression but there are limitations to Scolioscore as well, so the jury is out.
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.