Prospective evaluation of physical activity in patients with idiopathic scoliosis or kyphosis receiving brace treatment

Abstract

Bracing is an established method of conservative treatment for adolescent idiopathic scoliosis and kyphosis. Compliance among adolescents is frequently inadequate due to the discomfort of wearing a brace, cosmetic issues, and fear on the part of patients and parents that bracing may reduce everyday physical activities. The aim of this prospective, controlled study was to objectify the impact of spinal bracing on daily step activity in patients receiving conservative treatment for adolescent idiopathic scoliosis (AIS) or adolescent kyphosis (AK). Forty-eight consecutive patients (mean age 13.4 ± 2.3 years), consisting of 38 AIS patients (33 girls, 5 boys) and 10 AK patients (6 girls, 4 boys) were included. Once the decision to carry out bracing had been taken and while the patients were waiting for the individual brace to be built, step activity was assessed without braces by means of step activity monitoring (SAM) for seven consecutive days. After 8 weeks of brace wearing, step activity was assessed during regular brace treatment, again for seven consecutive days. In addition, brace-wearing times were simultaneously recorded using temperature probes implanted in the braces to measure compliance. Before and during brace treatment, patients completed the Scoliosis Research Society (SRS-22) questionnaire. The SAM was worn for an average of 12.7 ± 1.5 h/day during the first measurement and 12.3 ± 1.9 h on average during the second measurement. The mean gait cycles (GCs) per day and per hour before treatment were 5,036 ± 1,465 and 395 ± 105, respectively. No significant reduction in step activity was found at the follow-up measurement during bracing, at 4,880 ± 1,529 GCs/day and 403 ± 144 GCs/h. Taking the 23-h recommended time for brace wearing as a basis (100%), patients wore the brace for 72.7 ± 27.6% of the prescribed time, indicating an acceptable level of compliance. Girls showed a higher compliance level (75.6 ± 25.6%) in comparison with boys (56.7 ± 31.9%), although the difference was not significant (P = 0.093). The SRS-22 total score showed no differences between the two measurements (2.57 ± 0.23 vs. 2.56 ± 0.28). Implementing a simultaneous and objective method of assessing step activity and brace-wearing times in everyday life proved to be feasible, and it expands the information available regarding the impact of bracing on patients' quality of life. The results clearly show that brace treatment does not negatively interfere with daily step activity in AIS and AK patients. This is an important finding that should help reduce patients' and parents' worries concerning bracing.

Fig. 1

TheStepWatch Activity Monitor (SAM)

Fig. 2

The Chêneau (scoliosis) brace (a–c) and the kyphosis brace (d–f) (developed on the basis of the Milwaukee brace)

Fig. 3

Example illustrating a female adolescent idiopathic scoliosis patient, with simultaneous objective assessment of step activity (4,896 gait cycles) and compliance (84.3%, or 20.4 h of brace-wearing time) during 1 day. When the brace is taken off, the temperature drops below the threshold level of 28°C and immediately approximates to room temperature. Brace-wearing times can therefore clearly be distinguished from times when the brace is not worn

Fig. 4

A Bland–Altman plot indicating individual changes in daily step activity, measured by mean gait cycles (GCs) per hour between pretreatment (m1) and follow-up measurements (m2). The mean difference (m2 − m1) was +7.9 ± 106.9 GCs/h. A mark above the mean indicates greater step activity during the second measurement. The dashed lines represent means for differences ±2 SD

Fig. 5

Comparison of mean gait cycles (GCs) per minute during the follow-up measurements. GCs performed while wearing the brace: 14.5 ± 4.4 GCs/min (95% CI 13.2–15.8) and GCs performed without the brace: 14.2 ± 3.1 (95% CI 13.3–15.1). The difference was not significant (Mann–Whitney U test). The box plots represent the median, 25th and 75th percentiles, 1.5 interquartile range (IQR), and outliers