Natural History of Adolescent Idiopathic Scoliosis of 30 to 50 Degrees at Skeletal Maturity at Average 19+6 Year Follow-Up

Methods: Records from one institution were reviewed to identify patients who met all of the following inclusion criteria: Primary diagnosis of idiopathic adolescent scoliosis; Maximum scoliosis between 30 and 50 degrees at skeletal maturity (Risser 4 or 5); Minimum 10 years past skeletal maturity; No surgical intervention prior to skeletal maturity. Once patients were identified, letters were sent to solicit participation. Upon contact, patients were asked to complete a brief questionnaire including the SF36, Roland-Morris and Oswestry. Follow-up radiographs were obtained. The change in curve magnitude (Cobb angle) was determined; the average increase per year was determined by dividing the change by number of years of follow-up.

Results: A total of 46 patients (66 major curves - 44 thoracic, 6 upper thoracic and 16 TL or lumbar) were followed at least 10 years past skeletal maturity (average: 19+6 yrs; max: 37 + 8 yrs). Most patients were female (89%); 64% had had brace treatment; 36% had a family history of scoliosis.At the time of last follow-up, 30% of the curves had not increased (<5 º change), 33% increased between 6 and 10 degrees; 34% 11 20 degrees. Two curves had increases of more than degrees (22º 30º increases). The average increase per year was 0.4 95% the less one degree (range: -0.21 to 1.26). Neither location curve nor magnitude at time maturity influenced risk progression. (Table 1 Table 2, respectively) There no difference in progression based on history brace use, presence a family scoliosis or type, although small sample size limits power for detecting differences.To date, two patients (4%) have spine fusion surgery: due pulmonary compromise progressive curve; low back pain. Daily pain reported by 15% patients.Few functional limitations as indicated scores Roland-Morris (Median score="4," <7) Oswestry (median <24). standardized-normal SF36 were similar those normal population both composite all subscales, with exception General Health which slightly poorer (average z-score="46.2" compared 50.0, p< 0.01).

Conclusion: Adolescent idiopathic scoliosis curves between 30 and 50 degrees at skeletal maturity progress on average 0.5 degrees per year; few curves (4%) progressed more than a degree per year. Curve magnitude and type did not influence rate of progression. Two patients required posterior spinal fusion. Patient functionality overall was not compromised.

Table 1: Change in Cobb Angle (degrees) by Location Of Curve:

SEM: Standard Error of Mean

Table 2: Change in Cobb Angle (degrees) by Magnitude Currve at Maturity:

SEM: Standard Error of Mean