Global Spine Journal 2024, Vol. 14(2) 447–457
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sagepub.com/journals-permissions DOI: 10.1177/21925682221109565 journals.sagepub.com/home/gsj
The Relationship Between Compliance of Physiotherapeutic Scoliosis Speci fi c Exercises and Curve Regression With Mild to Moderate Adolescent Idiopathic Scoliosis
Yunli Fan, PT, MSc, BSc (hons)
1,2,3, Michael KT To, MBBS, FRCSEd, FHKCOS, FHKAM
1,2, Guan-Ming Kuang, MD, PhD
1, and
Jason Pui Yin Cheung, MBBS, MMedSc, MS, PDipMDPath, MD, MEd, FRCSEd, FHKCOS, FHKAM
1,2Abstract
Study Design:Retrospective Case-control Study.
Objectives:To determine the requisite exercise compliance (EC) of physiotherapeutic scoliosis-specific exercise (PSSE) for achieving curve regression; to analyze whether the apical translation (AT), apical wedging (AW), and apical rotation (AR) of the major curve improve with regression effect.
Methods: Between 2019 and 2021, a total of 763 patients undertook a 6-month PSSE treatment. This resulted 426 compliable and 302 uncompliable patients remained available for analysis. For compliable patients, 213 with curve regression and 213 age-/sex-matched with curve stabilization/deterioration at the 6-month, were eligible for regression analysis to detect the relationship between EC and regression effect at the 6-month; receiver operating characteristic (ROC) curve analysis and Youden’s index were applied to identify the threshold of EC leading to curve regression at the 6-month. The AT, AW, and AR of the major curve were compared before and after 6-month PSSE to investigate the radiographic parameters that improved with regression effect.
Results:EC was correlated with regression effect (odds ratio: 19.9, 95% confidence interval: 11.3-35.0, P < .001) and the cutoff threshold of EC was 4.4 h/week for 6 months to realize such an effect. AT was improved by 47.6% with curve regression, in which 152 cases remained curve regression and no case progressed into the operative threshold at the 1.5- to 2-year.
Conclusions:A 6-month PSSE protocol of 4.4 hours per week was potentially leading to curve regression in treating mild to moderate scoliosis. An improvement in AT of the major curve was observed with the regression effect.
Keywords
adolescent idiopathic scoliosis, physiotherapeutic scoliosis specific exercise, exercise compliance, curve regression, cobb angle, apical translation, apical wedging, apical rotation
1Department of Orthopaedics, The University of Hong Kong–Shenzhen Hospital, Shenzhen, People’s Republic of China
2Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong SAR, China
3Department of Physiotherapy, The University of Hong Kong–Shenzhen Hospital, Shenzhen, People’s Republic of China
Corresponding Author:
Jason Pui Yin Cheung, MBBS, MMedSc, MS, PDipMDPath, MD, MEd, FRCSEd, FHKCOS, FHKAM, Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong SAR, China.
Email:[email protected]
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Background
Adolescent idiopathic scoliosis (AIS) is the most common form of structural scoliosis with unknown etiology and is characterized by vertebral deformity in three dimensions.1 Surgery is reserved for severe curves exceeding 50°, whereas bracing and physiotherapeutic scoliosis-specific exercise (PSSE) are used for preventing curve progression.2
Studies have reported curve regressions after PSSE in treating mild to moderate scoliosis, with compliance noted as a crucial factor associated with significant improvement.3-8 However, exercise protocols have varied widely in those studies and have been reported using a percentage value of the prescribed dosage, yet without correlation analysis. Thus, the relationship between exercise compliance (EC) and curve regression remains unclear. In addition, the COVID-19 pan- demic has greatly affected hospital-visited treatments. Thus, having a PSSE program with appropriate EC to prevent curve progression while avoiding overtreatment is crucial.
PSSE reduces Cobb angles,4-6,8-12alleviates asymmetrical truncal rotation (ATR)12-16and improves quality of life.3,17 AIS is presented by vertebral side-deviation, rotation and wedging, and is characterized by an apical vertebra with the most deformed in rotation.18 Previous studies have not dis- cussed the mechanism through which PSSE affects the morphology of deformed vertebrae.3 Hence, the effects of PSSE on the change in apical translation (AT), apical wedging (AW), and apical rotation (AR) remain unknow. Under- standing the mechanism through which PSSE remodels a scoliotic spine aids research and clinical practice. Thus, we hypothesized that EC of a 6-month PSSE program is corre- lated with curve regression in treating mild to moderate scoliosis, and we aimed to define a threshold leading to such an effect. Furthermore, we aimed to investigate the effects of PSSE on change in radiographic parameters after PSSE.
Materials and Methods Patient Sampling
This was a retrospective, age-/sex-matched study with a balanced study design (sampling between regression and stabilization/deterioration was at a 1:1 ratio) to analyze the correlation between the EC and curve regression of patients undergoing 6-month PSSE without bracing between 2019 and 2021. This study was approved by the ethic committee of our hospital. The inclusion criteria were as follows: (1) idiopathic scoliosis; (2) adolescents aged≥10 and < 17 years; (3) initial Cobb angle < 50°; (4) available spinal radiographs before and after the 6-month PSSE; (5) initial spinal radiographs for at most 1 month before commencing PSSE; (6) Risser stage≤4;
(7) no bracing before and during the 6-month PSSE; and (8) once-monthly supervised PSSE to review performed exercise.
The exclusion criteria were as follows: (1) diagnoses other than AIS; (2) reported hypermobility on initial assessment
(Beighton score ≥4)19; (3) reported adherence to any other conservative treatments rather than the Schroth method; (4) atypical curve pattern.20 In particular, the second exclusion criterion was set to control systematic bias from hypermobility influencing effects of physiotherapy.21
PSSE Protocol and Compliance
The supervised PSSE comprised 1-h private sessions on workdays and 1-h group sessions on Saturdays. Each treat- ment comprised 50 breaths per exercise including: (1) active self-elongation with caudal-cranial spine lengthening in standing; (2) corrective exercise with shoulder counter traction and pelvic pulling strategy on the lumbar concavity in sitting/
standing/side-lying; and (3) stabilization exercises, per the protocol of a previous study.8The positioning of home ex- ercise (HE) was the same as supervised sessions. The HE comprised self-elongation and corrective exercises for 45- 60 min daily. This HE protocol was associated with a sig- nificant reduction in Cobb angle after 6 months of Schroth therapy.8,11 Patients in this study completed at least once- monthly supervised PSSE session to review the performed exercise and maintain exercise quality. The supervised PSSE attendance of patients was collected from the hospital’s da- tabase. HE compliance, hours per day, was self-reported by patients on a treatment adherence checklist (Supplemental file). This checklist was auto sent to patients/parents every 2- week. For calculation, daily compliance was set to 0 if noncompliance indicated. The patient would be called to refill the from if no reply in a week after checklist sent.
Radiographic Outcome and Group Allocation
Patients had whole spine standing radiographs with arms at the sides of body to assess their curve magnitudes. Cobb angle, AT, AW, and AR of the major curves were inde- pendently measured by two spine surgeons who were blinded to this study. The inter- and intra-rater reliabilities of radiographic measurements were studied before group allocation to diminish mislabeling. Prior to correlation analysis, change in Cobb angles at the 6-month was compared between compliable and uncompliable patients.
Compliable cohort was the patients completed once- monthly supervised PSSE for consecutively 6 months, this was for reviewing the performed exercise in every month to control exercise quality. Uncompliable cohort included patients undergoing only observation during the 6- month of treatment or did not complete once-monthly su- pervised PSSE for 6 months consecutively. Correlation analysis, the relationship between the EC and curve re- gression, would be conducted in the compliable cohort if a greater reduction of Cobb angle was detected with com- pliable patients. Compliable patients with a decrease of major coronal Cobb angle ≥ 6° were allocated into the
regression group, while patients with a change < 6° or an increase ≥ 6° were allocated into the stabilization/
deterioration group.22 This definition of curve progres- sion accounted for measurement error. The AR was graded as I to V using the Nash and Moe system (Figure 1).23AW was interpreted using the apical ratio (convex vertebral height/concave vertebral height; Figure 1).24 AT was de- fined as the distance between the center of the apical vertebrae of the major curve and central sacral vertical line (Figure 1).18The curve classification was defined as either major thoracic curve (single right thoracic or a major right thoracic with a minor left lumbar) or major lumbar curve (single left lumbar, a major left lumbar with a minor right thoracic, or a thoracolumbar). Skeletal maturity was as- sessed by Risser signs with 0-referring to Risser sign 0 with
open triradiate cartilage and 4+ referring capped iliac apophysis but not completely fused.
Statistical Analysis Sample size estimation
This study adopted a balanced design. Thus, the curve re- gression prevalence (p) was .5; the events per variable (EPV) was set at 40; the failure rate (f) in data collection, such as EC of HE, was estimated to be 20%; and 4 features (k), namely the Risser sign, Cobb angle, curve pattern, and EC, were adopted for the logistic regression analysis (n = [EPV×k/p]/[1f]).
Overall, 200 in each group were required for intergroup as- sociations to be detected.25
Data Analysis
Descriptive statistics were calculated for baseline demo- graphic and radiographic data. Continuous variables were presented as mean ± standard deviation (SD) with and without median values depending on normality tests. The intraclass correlation coefficient (ICC) and Cohen weighted kappa (kw) were conducted to investigate the inter- and intra-rater reli- ability of radiographic outcomes. EC was documented in hours per week of 6 months. Continuous variables, including age, body mass index, initial Cobb angle, Lostein and Carlson risk of progression
LCRvalue¼CobbAge3 × Risser
before PSSE,26and EC were compared using a Mann-Whitney U test if normality was violated; categorical variables, including curve patterns (T/L) and Risser sign (0-2/3-4), were compared between groups using a chi square test. Prior to correlation analysis, a greater reduction of Cobb angles was detected at the 6-month in the compliable cohort, thus, a logistic re- gression was performed to investigate the relationship be- tween EC and curve regression for compliable patients. The risk factors for scoliosis progression are age, a female sex, skeletal immaturity, and a thoracic curve with a large mag- nitude.27 However, age and sex were matched before data analysis, and thus, only the Risser sign, initial Cobb angle, and curve pattern were considered together with EC in the logistic regression analysis. If EC was significantly correlated with curve regression, receiver operating characteristic (ROC) curve analysis and Youden’s index were applied to identify the threshold of EC leading to curve regression. Matched vari- ables, including AT, AW, and AR, were compared before and after 6 months of PSSE in patients with curve regression to detect any radiographic changes. The correspondingfindings indicate the variation in vertebral morphology with curve regression.
The data were analyzed using SPSS version 20.0 (IBM, Chicago, IL). Significance was set at a two-tailed level of .05.
The 95% confidence intervals (CIs) and respective odds ratios (ORs) were reported where appropriate.
Figure 1. One radiograph illustrating the measurements of apical translation (AT), apical wedging (AW) and apical rotation (AR). AT was defined as the distance in millimeter (dashed, horizontal yellow line) between the center of the apical vertebrae (T8: white round marker) and the central sacral vertical line (CSVL, solid vertical white line). AW was interpreted as the apical ratio equals convex vertebral height (solid, red vertical line on the T8 convexity) divided by concave vertebral height (solid, red vertical line on the T8 concavity) of the apical vertebrae. AR was graded as rotational I, II, III and V regarding the radiographic location of the pedicle on convexity of the apical vertebrae (three dashed, vertical white lines).
Results
Patient Sampling
A total of 2072 patients with AIS were assessed for eligi- bility, of those, 1309 patients were excluded due to the following reasons (Figure 2): (1) they did not perform spinal radiographic assessment at the 6-month (n = 308); (2) their initial spinal radiography was not within 1 month before commencing PSSE (n = 304); (3) they undertook (n = 88) or initiated (n = 128) spinal orthotic treatment at their first consultation; (4) they reported hypermobility at initial as- sessment (n = 82); (5) they did not complete once-monthly supervised PSSE to review performed exercise (n = 302); (6) they underwent any other conservative treatment rather than
the Schroth method during the 6 months of PSSE (n = 58).
Consequently, 763 patients met the inclusion criteria, of those, 228 radiographs were randomly captured to test the reliability of radiographic measurements. The interrater re- liability of Cobb angle (ICC = .98), AT (ICC = .90), AW (ICC = .95), AR (kw = .93) and Risser sign (ICC = 1.00) revealed a strong agreement between measurements; the intrarater reliability was also satisfactory (Cobb angle [ICC =1.0], AT [ICC = .92], AW [ICC = .87], AR [kw= .99]
and Risser sign [ICC= 1.00]). After radiographic measure- ments, a total of 309 patients exhibited curve regression (reduction in Cobb angle by 6°–15°); 439 patients exhibited curve stabilization, and 15 patients exhibited curve deteri- oration by 6°–9° after 6-month PSSE. In total, 213 pairs/
Figure 2. Studyflow chart.
stratum of age- and sex-matched cases, with 4.4° of re- ductions compared to the uncompilable cohort (n = 302, 2.1°
increase in Cobb angles at 6-month), remained available for correlation analysis (Table 1).
Threshold of EC With Curve Regression
Overall, 5964 HE adherence checklists were collected, of which 91% of daily EC was reported whereas 9% was set to 0 due to noncompliance. Significant intergroup differences were observed in EC whereby the distribution of supervised/home session was same between groups (Table 2).
A logistic regression analysis suggested that curve re- gression was related with EC (OR: 19.9, 95% CI: 11.3-35.0, P< .001) (Table 3). An ROC graphic analysis revealed an excellent accuracy, 93% of the area under the curve, of using PSSE compliance for 6 months to predict the effects of PSSE on curve regression (Table 2). The maximum value of You- den’s index was .7 (sensitivity: .87 and specificity: .85) at the cutoff score of 4.4 h/week (Figure 3).
Radiographic Outcomes
Mann-Whitney U tests were used in intergroup analysis be- cause normality was violated. No difference of radiographic characteristic at the first assessment was observed between compliable and uncompilable cohorts (Table 1). After 6- month PSSE, a significant improvement (47.6%) of AT with curve regression was observed; a significant intergroup difference was observed in AT (P< .001) but not in AR and AW (Table 4). A spearman correlation (rs) test was performed and revealed that age did not influence effects of PSSE in reducing Cobb angles (rs =.9,P = .2). The curve pattern remained unchanged for all participants except one 12-year- old girl with a single left lumbar of 15° exhibited lumbar curvature deterioration by 6° and developed a mild right thoracic of 20° after 6 months of PSSE. In the regression group, 152 patients (73.4%) maintained the regression effect, whereas 61 patients (26.6%) resulted in the curve stabilization at the 1.5-year (Table 4). Three patients with a curve stabi- lization at the 6-month, who received spinal fusion at the 2- year after PSSE.
Table 1. Characteristics of Compliable and Uncompliable Patients.
Compliable cohort (n = 426) Uncompliable cohort (n = 302)
Age:years (Median, mean ± SD) 13 (12.9 ± 1.6) 13 (13.1 ± 1.6)
Sex:n (female/male) 362 (85%)/64 (15%) 258 (85%)/44 (15%)
Body mass index (BMI)
Median, mean ± SD 18.2 (18.5 ± 1.9) 18.4 (18.7 ± 2.0)
Risser sign (n: 0-- 2/3–4+) 154 (36%)/272 (64%) 105 (35%)/197 (65%)
0- 19 10
0 39 29
1 14 16
2 82 50
3 70 46
4 152 110
4+ 50 41
Initial curve Pattern: n (%)
Major T curve/major L curve 251 (59%)/175 (41%) 181 (60%)/121 (40%)
Risk score of progression:Lonstein and Carlson risk of scoliosis progression (Median, mean ± SD)
1.3 (1.3 ± .4) 1.3 (1.3 ± .4)
Percentage value of progression risks 40% 40%
Cobb angle:°(Median, mean ± SD)
Before PSSE 25° (24.8 ± 6.2°) 25° (25.7 ± 6.1°)
At the 6-month 21°a(20.5 ± 7.1°) 28° (27.8 ± 6.3°)
Changes of Cobb angles after 6 months 5.5°a(4.4 ± 4.2°) 2° (2.1 ± 3.4°)
Scoliosis progression at 6-month(n: %)
Curve regression 213 (50%)b 0
Curve stabilization 203 (48%)c 242 (80%)
Curve deterioration 10 (2%)c 60 (20%)
aMann-Whitney U test revealed a statistical significance between groups at the 6-month.
bpatients allocated into the regression group for regression analysis.
cpatients allocated into the stabilization/deterioration group for regression analysis.
Discussion
Studies demonstrated the ability of PSSE to reduce the Cobb angle3,7-9,11,17
; it is thus crucial to determine the EC realizes such a reduction. In addition, the effects of PSSE in changing vertebral monography remain unknown, understanding these effects can help researchers discover how PSSE remodels deformed vertebrae. This study defined the cutoff threshold of EC leading to curve regression and revealed that AT improved with the curve regression.
Our findings indicate that 4.4 h of PSSE per week for 6 months is the requisite EC to achieve curve regression with mild to moderate AIS. Thisfinding differs from studies that have only demonstrated that better compliance influences better outcomes without a correlation analysis.17 Moreover, the reduction of Cobb angle in those studies was noted within the measurement error.3,17 More recent PSSE studies have reported curve regression in mild to moderate scoliosis but with a variation in exercise protocols.4-6,8,11,13
In these trials, spinal orthosis was used with PSSE to treat AIS; thus, the outcome could be influenced by both bracing and exercise.
Our study excluded patients with orthotic treatment, which limited the confounding effect of bracing. Two CCTs4,5have reported a significant reduction by >5° for mild scoliosis, in which EC was related with curve regression, but the threshold of EC was not defined. Investigating this relationship is valuable because PSSE compliance varies between coun- tries.28Our studyfilled this knowledge gap in the literature.
Regarding the exercise protocol, daily PSSE for 30-45 min has been consistently prescribed in most studies,29and, thus, to achieve 4.4 h/week of PSSE, 45 min/day for 6 days would be a recommended exercise dose for patients undergoing PSSE treatment. Moreover, our study adopted a clinically significant change in Cobb angle by≥6° to verify improvement, which is Table 2. Characteristics of Compliable Patients with Curve Regression and Stabilization/Deterioration.
Regression group (n = 213) Stabilization/deterioration group (n = 213)
Age:years (Median, mean ± SD) 13 (12.9 ± 1.6) 13 (12.9 ± 1.6)
Sex:n (female/male) 181 (85%)/32 (15%) 181 (85%)/32 (15%)
Body mass index(BMI)
Median, mean ± SD 18.3 (18.6 ± 2.1) 18.0 (18.3 ± 1.7)
Risser sign (n: 0 -2/3 -4) 81 (38%)/132 (62%) 75 (35%)/138 (65%)
0- 10 9
0 18 21
1 9 5
2 43 39
3 30 40
4 77 72
4+ 25 25
Initial Cobb angle:Median, mean ± SD 24° (24.5 ± 6.3°) 25° (25.1 ± 6.2°) Initial curve Pattern: n (%)
Major T curve/major L curve 125 (59%)/88 (41%) 126 (59%)/87 (41%)
Risk score of progression (LCR):
Median, mean ± SD 1.2 (1.3 ± .5) 1.3 (1.3 ± .4)
Percentage value of progression risks 40% 40%
Exercise compliance:h/week
Sum value (Median, mean ± SD) 5 (5.1 ± .7) 3.6* (3.6 ± .7)
Supervised PSSE
(Median, mean ± SD), % .75 (.7 ± .3), 14% .5* (.5 ± .3), 14%
Home program
(Median, mean ± SD), % 4.5 (4.4 ± .7), 86% 3* (3.1 ± .7), 86%
Abbreviations: SD, standard deviation; T, thoracic; L, lumbar; LCR, Lonstein and Carlson risk of scoliosis progression; h/week, hours per week; PSSE, physiotherapeutic scoliosis-specific exercise.
* Mann-Whitney U test revealed a significant difference between groups (P<.001).
Table 3. Logistic Regression Analysis of Intergroup Associations Between Risk Factors with Exercise Compliance and Curve Regression after 6-month of Physiotherapeutic Scoliosis-Specific Exercise.
OR 95% CI Pvalue
Risser sign 0.8 .4 - 1.7 .5
Initial Cobb angle 1.0 .9 - 1.0 .1
Initial curve pattern 0.9 .5 - 1.7 .8
Exercise compliance 19.9 11.3 - 35.0 <.001 Abbreviations: OR, odds ratio; CI, confidence interval; T, the major thoracic curves; L, the major lumbar curves; h/week, ours per week.
of clinical value because any change <5° is not considered a true improvement.24Additionally, ourfindings did not suggest that the effect of supervised PSSE was superior to home PSSE, although previous studies have reported this.9This might be because the compliance of supervised PSSE in this study was only 14% in each group. Hence, the effect of HE was un- derscored in this study. This observation suggests that one
supervised session per month, where the aim is to review the exercise performed, with a PSSE program of 45 min/day for 6 days is a feasible PSSE protocol for treating AIS. However, it is possible for mild scoliosis to not progress regardless of interventions.27Thus, this exercise protocol may benefit pa- tients in preventing overtreatment of supervised PSSE and lowering the costs; however, a cost-effectiveness study is Figure 3. Exercise compliance in hours per week of 6 months. The cut-off threshold was 4.4 hours per week that led to a curve regression.
Table 4. Radiographic Parameters Before and After 6 Months of Physiotherapeutic Scoliosis-Specific Exercise Treatment.
Regression group (n = 213) Stabilization/deterioration group (n = 213) Pvalue Cobb angle (Median, mean ± SD)
Initial Cobb angle 24° (24.5 ± 6.3°) 25° (25.1 ± 6.2°) 0.2
6-month 15° (17.0 ± 6.3°) 25° (24.0 ± 6.0°) <.001
1.5- to 2-year 18° (18.4 ± 5.3°) 25° (25.5 ± 6.2°) <.001
D-value at the 6-month 7° (7.6 ± 1.7°) 3° (1.2 ±3.4°) <.001
Regressed/stabilized/deteriorated:n
6-month 213/0/0 0/203/10 -
1.5- to 2-year 152/61/0 0/203/10 -
Curve patten(T/L, n: %):
Initial curve pattern 125 (59%)/88 (41%) 126 (59%)/87 (41%) 0.9
Curve pattern at the 6-month 125 (59%)/88 (41%) 125 (59%)/88a(41%) 0.9
AT(mm: Media, mean ± SD):
Initial AT 37.2 (37.6 ± 9.0) 36.8 (36.0 ± 9.1) .1 <.01
6-month 20b(20.7 ± 10.6) 32.1 (32.8 ± 9.4) <.001
Improvement of AT (%) 47.6% 8.2%
AW(Median, mean ± SD):
Initial AW 1 (1.1 ± .9) 1 (1.0 ± .8) .1
6-month 1 (1.1 ± .1) 1 (1.0 ± .1) .5
AR(n: grade I/grade II)
Initial AR (AR at the 6-month) 171/42 (171/42) 157/56 (160/53) .1 (.2)
Abbreviations: SD, standard deviation; D-value, a difference value of Cobb angles after 6 months of PSSE; T, the major thoracic curves; L, the major lumbar curves; AT, apical translation; AW, apical wedging; AR, apical rotation.
aone major lumbar curve changed to double mild curves after 6-month PSSE.
bsignificantly decreased from the initial value with curve regression and differed between groups at the 6-month.
required to reach a clearer conclusion. In addition, our study suggested that patients’age did not influence the effects of PSSE in reducing Cobb angles. This differs from previous evidence. One study revealed a greater reduction of Cobb angles in patients ≥ 13 years doing active self-correction exercises.5 Another study, on the contrary, found a greater reduction in patients < 13 years doing an alternative scoliosis- specific exercise named Xinmiao approach.4 These differ- ences might be introduced by varied exercise protocols. Thus, the correlation of age and PSSE in alleviating scoliosis re- quires future study to confirm.
Patients with curve regression exhibited a significant im- provement of AT. Prior study explained that exercise can rebuild trunk symmetry with respect to ATR improvement, thereby altering spinal alignment.30One study evaluated the effect of PSSE with angular breathing technique on vertebral rotation, reporting a significant improvement in AR by .6° but the study ended at the 3-month.31 Angular breathing is one practical technique of the Schroth method to open the curve concavity, derotate the asymmetrical ribcage, which may affect vertebral rotation.30However, no study has addressed the effect of PSSE on vertebral morphology including AT, AR and AW.3 Our study filled this knowledge gap, providing clinicians with additional information regarding the benefits of PSSE in correcting vertebral side deviation. One thoracic curve (Figure 4A and B) achieved a 14° reduction, and one
lumbar curve (Figure 4C and D) achieved a 10° reduction after PSSE. Those effects were presented with significant im- provements in AT. This implies that PSSE balances spinal coronal asymmetry. However, curvature reducibility before PSSE could not be quantified in our analysis owing to the retrospective nature of our study. Nevertheless, ourfindings form a basis for defining the relationship of PSSE with defined curvatureflexibility and curve regression in future studies. No changes in structural rotation and wedging were expected because vertebral morphology cannot be easily altered simply with exercise. However, vertebral rotation and wedging may be altered with prolonged PSSE if the external symmetrical forces can influence internal development during bone growth. However, the current evidence contains no infor- mation on such a relationship.3 Furthermore, one patient exhibited a curve progression of 6° in the lumbar region and developed a mild thoracic curve of 20°. Thus, overcorrection may alter curve pattern. Nine patients with high progression risks gained 6°–9° in Cobb angles after 6 months. Hence, our finding of 4.4 h/week of PSSE may not be applicable for treating scoliosis with a high progression risk.
No curve deterioration was observed at the 1.5-year in patients with curve regression at the 6-month. Such regression had worn off and resulted in curve stabilization for 61 patients.
This introduced a bouncing effect after PSSE. Nonetheless, 71.4% of patients, with curve regression at the 6-month,
Figure 4. Radiograph of two patients before and after 6-month PSSE. A: radiograph demonstrating a 36° thoracic curve (T4 to T11) with 44.1 mm of apical translation to the right before PSSE. B: radiograph revealing a 22° thoracic curve (T4 to T11) with 19.5 mm apical translation to the right PSSE while the rotation and wedging of the apical vertebrae (T8) remained unchanged. C: radiograph demonstrating a 36° lumbar curve (T12 to L4) with 37.9 mm of apical translation to the left before PSSE. D: radiograph revealing a 26° lumbar curve (T12 to L4) with 20.6 mm apical translation to the left after PSSE, while the rotation and wedging of the apical vertebrae (L2) remained unchanged.
Abbreviation: PSSE, physiotherapeutic scoliosis-specific exercise.
maintained curve regression and no one received operation at end of this study. This revealed a promising effect of 6-month PSSE in avoiding scoliosis deterioration.8,13Like bracing in AIS, the rate of treatment success was 72% after bracing, as compared with 48% for observation only.32Thus, the efficacy of PSSE in alleviating scoliosis requires a prospective ran- domized trial with an observation only group as control to draw a conclusion. In the stabilization/deterioration group of this study, three patients, with a curve magnitude ≥ 42° at study initiation, received spinal fusion at the 2-year. This implies that a 6-month long of PSSE might not being effective in treating severe scoliosis.3
Because of the retrospective nature of this study, baseline variances could not be completely controlled. Firstly, the initial Cobb angle was <30° and presented with progression risk < 50% in this study cohort. Hence, the threshold defined cannot be applied to patients with severe scoliosis or high progression risks. This might be caused by the exclusion of cases with orthotic treatment. Regarding the Scoliosis Re- search Society guideline,2 moderate scoliosis with high progression risks should start orthosis at interventional initiation. In this study, we excluded patients with bracing, which eliminated the confounding effect of bracing. Sec- ondly, self-compliance for PSSE can be uncertain like that of bracing and may lack accuracy. One study reported the bracing compliance rate to average 88% while the compli- ance monitor device only reported 33%.33Thus, reporting of compliance to HE can be variable according to the prescribed amount of time, what the patient reports, what the parents say, and the actual time of doing HE. Hence, self-reported compliance introduced internal recall bias in this study.
However, given to the compliance was collected every 2- weeks, the recall bias was externally limited. Lastly, this study excluded numerous cases. Nonetheless, this was a controlled and homogeneous study, and confounding effects were eliminated; thus, the effect of PSSE was more accu- rately captured.
Acknowledgments
We would like to thank Helen Zhi, the senior statistician of our university, who was blinded to this study andfinal checked on the data analysis. We also thank all patients with their parents. Re- viewer’s comments are also gratefully acknowledged.
Author Contributions
Yunli Fan: Manuscript draft and editing. Michael KT To and Guan- Ming Kuang: Imaging assessor and data collection. Jason PY Cheung: Performed the operation, manuscript editing, conceptuali- zation, funding receiver.
Author Note
This study was performed in the University of Hong Kong – Shenzhen hospital, Shenzhen, Guangdong province, China.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the followingfinancial support for the research, authorship, and/or publication of this article: This study was financially supported by the high level – hospital program (HKUSZH201902042) of the HKU - SZH in Shenzhen, Guangdong Province, China. This study was partially supported by Hong Kong Research Grant Council Research Impact Fund (R5017-18).
Ethics Approval
The University of Hong Kong- Shenzhen Hospital Ethics Com- mittee(s) approved this study. (IRB reference No.:伦[2020]08)
Content to Participate
All participants/patients and parents signed consent form before data collection, agreed with analyzing their radiographic parameters and documented treatment compliance.
Content to Publish
All authors approved thefinal manuscript before submitting to this journal. Individuals in this manuscript have given written informed consent to publish these case details.
Trial Registration
This study was registered on the Chinese Clinical Trial Registry (https://www.chictr.org.cn/) with the reference number ChiCTR2100050293.
Availability of Data And Material
Raw data will be saved using the online electronic management database -Redcap. Data will be set as open access within 6 months after manuscript published.
ORCID iD
Yunli Fanhttps://orcid.org/0000-0001-9936-8857
Supplemental Material
Supplemental material for this article is available online.
References
1. Weinstein SL, Dolan LA, Cheng JC, Danielsson A, Morcuende JA. Adolescent idiopathic scoliosis. Lancet. 2008;371(9623):
1527-1537.
2. Korbel K, Kozinoga M, Ł Stoli ´nski, Kotwicki T. Scoliosis research society (SRS) criteria and society of scoliosis ortho- paedic and rehabilitation treatment (SOSORT) 2008 guidelines
in non-operative treatment of idiopathic scoliosis.Pol Orthop Traumatol. 2014;79:118-122.
3. Fan Y, Ren Q, To MKT, Cheung JPY. Effectiveness of scoliosis- specific exercises for alleviating adolescent idiopathic scoliosis:
a systematic review.BMC Musculoskelet Disord. 2020;21(1):
495.
4. Liu D, Huang S, Yu X, et al. Effects of specific exercise therapy on adolescent patients with idiopathic scoliosis: a prospective controlled cohort study. Spine (Phila Pa 1976). 2020;45:
1039-1046.
5. Monticone M, Ambrosini E, Cazzaniga D, Rocca B, Ferrante S.
Active self-correction and task-oriented exercises reduce spinal deformity and improve quality of life in subjects with mild adolescent idiopathic scoliosis. Results of a randomised con- trolled trial.Eur Spine J. 2014;23(6):1204-1214.
6. Zapata KA, Sucato DJ, Jo CH. Physical therapy scoliosis- specific exercises may reduce curve progression in mild ado- lescent idiopathic scoliosis curves. Pediatr Phys Ther. 2019;
31(3):280-285.
7. Gao A, Li JY, Shao R, et al. Improvement of health-related quality of life and radiographic parameters in adolescent idio- pathic scoliosis patients after Schroth exercises. Chin Med J (Engl). 2021;134:2589-2596.
8. Fan Y, To MKT, Yeung EHK, Wu J, He R, Xu Z, et al. Does curve pattern impact on the effects of physiotherapeutic scoliosis specific exercises on Cobb angles of participants with adolescent idiopathic scoliosis: A prospective clinical trial with two years follow-up.PLoS One. 2021;16(1):e0245829.
9. Kuru T, Yeldan I, Dereli EE, Ozdincler AR, Dikici F, Colak I.
The efficacy of three-dimensional Schroth exercises in ado- lescent idiopathic scoliosis: a randomised controlled clinical trial.Clin Rehabil. 2016;30(2):181-190.
10. Negrini S, Atanasio S, Fusco C, Zaina F. Effectiveness of complete conservative treatment for adolescent idiopathic scoliosis (bracing and exercises) based on SOSORT management criteria: results according to the SRS criteria for bracing studies - SOSORT Award 2009 Winner.Scoliosis. 2009;
4:19.
11. Schreiber S, Parent EC, Khodayari Moez E, et al. Schroth physiotherapeutic scoliosis-specific exercises added to the standard of care lead to better cobb angle outcomes in ado- lescents with idiopathic scoliosis - an assessor and statistician blinded randomized controlled trial. PLoS One. 2016;11(12):
e0168746.
12. Yagci G, Ayhan C, Yakut Y. Effectiveness of basic body awareness therapy in adolescents with idiopathic scoliosis: A randomized controlled study1.J Back Musculoskelet Rehabil.
2018;31(4):693-701.
13. Kwan KYH, Cheng ACS, Koh HY, Chiu AYY, Cheung KMC.
Effectiveness of Schroth exercises during bracing in adoles- cent idiopathic scoliosis: results from a preliminary study- SOSORT Award 2017 Winner.Scoliosis Spinal Disord. 2017;
12:32.
14. Schreiber S, Parent EC, Hill DL, Hedden DM, Moreau MJ, Southon SC. Patients with adolescent idiopathic scoliosis per- ceive positive improvements regardless of change in the Cobb angle - Results from a randomized controlled trial comparing a 6-month Schroth intervention added to standard care and standard care alone. SOSORT 2018 Award winner. BMC Musculoskelet Disord. 2019;20(1):319.
15. Yagci G, Yakut Y. Core stabilization exercises versus scoliosis- specific exercises in moderate idiopathic scoliosis treatment.
Prosthet Orthot Int. 2019;43(3):301-308.
16. Zheng Y, Dang Y, Yang Y, et al. Whether orthotic management and exercise are equally effective to the patients with adolescent idiopathic scoliosis in mainland china?: A randomized con- trolled trial study. Spine (Phila Pa 1976). 2018;43(9):
E494-e503.
17. Day JM, Fletcher J, Coghlan M, Ravine T. Review of scoliosis- specific exercise methods used to correct adolescent idiopathic scoliosis.Arch Physiother. 2019;9:8.
18. La Maida GA, Peroni DR, Ferraro M, Della Valle A, Vitali C, Misaggi B. Apical vertebral derotation and translation (AVDT) for adolescent idiopathic scoliosis using screws and sublaminar bands: a safer concept for deformity correction. Eur Spine J.
2018;27(suppl 2):157-164.
19. Smits-Engelsman B, Klerks M, Kirby A. Beighton score: a valid measure for generalized hypermobility in children. J Pediatr.
2011;158(123):119-234. e1.
20. Malfair D, Flemming AK, Dvorak MF, et al. Radiographic evaluation of scoliosis: review. AJR Am J Roentgenol. 2010;
194(3 suppl l):S8-S22.
21. Czaprowski D, Kotwicki T, Pawłowska P, Stoli ´nski L. Joint hypermobility in children with idiopathic scoliosis: SOSORT award 2011 winner.Scoliosis. 2011;6:22.
22. Cheung JPY, Cheung PWH, Samartzis D, Luk KD. Curve Progression in Adolescent Idiopathic Scoliosis Does Not Match Skeletal Growth.Clin Orthop Relat Res. 2018;476(2):429-436.
23. Nash CL Jr., Moe JH. A study of vertebral rotation.J Bone Joint Surg Am. 1969;51(2):223-229.
24. Cheung JPY, Cheung PWH, Yeng WC, Chan LCK. Does curve regression occur during underarm bracing in patients with ad- olescent idiopathic scoliosis? Clin Orthop Relat Res. 2020;
478(2):334-345.
25. Kim S, Heath E, Heilbrun L. Sample size determination for logistic regression on a logit-normal distribution.Stat Methods Med Res. 2017;26(3):1237-1247.
26. Lonstein J, Carlson J. The prediction of curve progression in untreated idiopathic scoliosis. J Bone Jt Surg. 1984;3(2):
1061-1071.
27. Weinstein SL. The natural history of adolescent idiopathic scoliosis.J Pediatr Orthop. 2019;39(6 suppl 1):S44-S46.
28. Berdishevsky H, Lebel VA, Bettany-Saltikov J, et al. Phys- iotherapy scoliosis-specific exercises - a comprehensive re- view of seven major schools.Scoliosis Spinal Disord. 2016;
11:20.
29. Negrini S, Donzelli S, Aulisa AG, et al. 2016 SOSORT guidelines: orthopaedic and rehabilitation treatment of idio- pathic scoliosis during growth.Scoliosis Spinal Disord. 2018;
13:3.
30. Lehnert-Schroth C. [Schroth’s three dimensional treatment of scoliosis].ZFA (Stuttgart). 1979;55(34):1969-1976.
31. Noh DK, You JS, Koh JH, et al. Effects of novel corrective spinal technique on adolescent idiopathic scoliosis as assessed
by radiographic imaging.J Back Musculoskelet Rehabil. 2014;
27(3):331-338.
32. Weinstein SL, Dolan LA, Wright JG, Dobbs MB. Effects of bracing in adolescents with idiopathic scoliosis.N Engl J Med.
2013;369(16):1512-1521.
33. Vandal S, Rivard CH, Bradet R. Measuring the compliance behavior of adolescents wearing orthopedic braces. Issues Compr Pediatr Nurs. 1999;22(2-3):59-73.
