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Postural Rehabilitation for Adolescent Idiopathic Scoliosis during Growth

Long-term follow-up of untreated patients with adolescent idiopathic scoliosis (AIS) indicates that, with the exception of some extremely severe cases, AIS does not have a significant impact on quality of life and does not result in dire consequences. In view of the relatively benign nature of AIS and the long-term complications of surgery, the indications for treatment should be reviewed. Furthermore, recent studies have shown that scoliosis-specific exercises focusing on postural rehabilitation can positively influence the spinal curvatures in growing adolescents. Experiential postural re-education is a conservative, non-invasive approach, and its role in the management of AIS warrants further study. This article reviews current evidence for the inclusion of various forms of postural reeducation in the management of AIS. Recent comprehensive reviews have been researched including a manual and PubMed search for evidence regarding the effectiveness of physical/postural re-education/physiotherapy programs in growing AIS patients. This search revealed that there were few studies on the application of postural re-education in the management of AIS. These studies revealed that postural re-education in the form of exercise rehabilitation programs may have a positive influence on scoliosis; however, the various programs were difficult to compare. More research is necessary. There is at present Level 1 evidence for the effectiveness of Schroth scoliosis exercises in the management of AIS. Whether this evidence can be extrapolated to include other forms of scoliosis- pattern-specific exercises requires further investigation. Because corrective postures theoretically reduce the asymmetric loading of the spinal deformities and reverse the vicious cycle of spinal curvature progression, their integration into AIS programs may be beneficial and should be further examined.


Introduction
Adolescent idiopathic scoliosis (AIS) is defined as a three dimensional spinal deformity [1][2][3][4] with no identifiable causes [5,6] in a growing child who is otherwise healthy. On inspection, the child can be seen with trunk asymmetry, which is accentuated in forward bending. This is because the costal or lumbar hump becomes more prominent in this position. A "costal hump" evolves as the ribs on the thoracic concave side twist in a ventral direction.
A diagnosis of scoliosis is verified by an X-ray of the full spine with the patient in a standing position [7].
The reported rate of progression of AIS varies according to the study [8][9][10]. This may be due to differences in the samples studied and the definition of 'progression' . It is possible that a small percentage of those with minor distortions may resolve [8]. In contrast, Lonstein and Carlson [8] and Sahlstrand and Lidstrom [11] reported that curves of greater severity have a higher probability of progression. When considering comparable-sized curvatures, females are four to ten times more likely to experience progression, when compared to males [3,12]. As skeletal maturity increases, the risk of progression decreases. Yet, greater curves still tend to worsen after skeletal maturity [7,13,14].
Since the causes of AIS are not clear, this has led to a variety of different treatment options. Up until recently, little attention has been paid to the role of postural rehabilitation in the management of AIS, despite the fact that it has been shown to be effective when integrated into scoliosisspecific exercises [15].
Treatment indications for scoliosis depend on the magnitude of the curvature at presentation and maturity of the patient [3,4,7]. Historically, in central Europe, treatment has consisted of the following protocols: (1) Observation in mild curvatures during growth. (2) Brace treatment in curvatures exceeding 20° during growth. (3) Postural rehabilitation in moderate curvatures during growth and for curvatures exceeding 35° after growth [4]. (4) Spinal fusion surgery.
In 1921, Katharina Schroth of Germany began to address the role of body mechanics for the treatment of scoliosis with an emphasis on rotational breathing [7]. Scoliosis patients display an asymmetric breathing pattern [16], which tends to rotate the thorax and aggravates spinal deformities. Breathing forces are directed towards the convexity of the spinal curvature, which results in increased trunk rotation. Regular deep breathing using the dysfunctional breathing pattern should be avoided [16]. Dysfunctional breathing patterns and incorrect postures during activities of daily living (ADL) have all been implicated in the pathogenesis of spinal curvatures [16]. They may be important as progression factors [17], particularly in AIS patients with Cobb angles in excess of 30°.
Similarly, posture may positively or negatively influence spinal curvatures [18]. Adoption of corrective postures (Table 1) during daily activities would avoid improper curve loading during the day. Incorrect postures during daily activities would increase asymmetric vertebral loading and growth in a scoliotic [19]. It is possible that for these reasons many practitioners instruct patients not to slump into habitual postures after performing scoliosis patterns specific exercises [7,16]. Failure of maintaining correct or corrective postures at rest may nullify all the efforts spent in performing the exercises [16]. Exercises and sports are beneficial to the overall health of individuals. Patients with AIS are encouraged to exercise regularly [17]. Despite this, certain activities may exacerbate spinal asymmetries. One example is a recent study that found that competitive swimming might increase spinal asymmetries and spinal curvatures [20]. The finding, though preliminary, is important in view of the fact that many physicians advise their scoliosis patients to swim to improve the back muscle strength and endurance, without realizing the possible risks. Owing to the possibility of improper postures causing progression of spinal curvatures, postural training has been integrated into certain scoliosis treatment programs. Here, we investigate the role and the effectiveness of various exercise-based programs and/or postural rehabilitation techniques in the management of AIS.

The role of posture in activities of daily living
Some postures can influence the spinal curvatures positively or negatively, depending on the curve types. A kneeling movement may aggravate a thoracolumbar or lumbar curve, but reduce a thoracic curve [16]. On the contrary, contralateral kneeling movement may exaggerate the thoracic curve and reduce the thoracolumbar or lumbar curvatures (Table 1). Similarly, sitting with legs crossed on the floor may affect the spinal alignment positively or negatively [16]. Unfortunately, the importance of these clinical observations has not been studied, let alone the impact of scoliosis-curve-specific ADLs on the pathogenesis of scoliosis progression.
Extension, lateral flexion and rotation exercises [16] have been reported to be contraindicated in AIS. Back extension exercises reduce thoracic kyphosis. This may destabilize the thoracic spine, increase its propensity for lateral flexion and rotation, and increase the spinal curvature [21]. AIS patients, particularly those with double curves, should also avoid performing lateral flexion exercises [16]. Laterally flexing to one side reduces one of the curvatures, but increases the other. Swedish bending exercises that were advocated more than 50 years ago were found to cause progression of scoliosis in many cases [16]. Rotational exercises have also been reported to increase rib hump [16].

Side-shift
Depending on the curve types, patients are advised to side-shift to open up and relieve the pressure from the concavities of the curvature [7,16,22]. Gram and Hasan [18] found that AIS patients tend to lean towards the side of convexity. The lateral lean increases the overhang of the right thorax and could possibly increase the deformity of the spine. To counteract this, patients with right thoracic scoliosis are advised to shift towards the side of concavity to open up the thoracic concavity and to reduce the curvature during relaxed sitting [7,16].

Sitting postures
School children spend many hours writing, reading, watching TV and doing homework on a daily basis. Their sitting postures are important, because improper sitting postures may result in progression of spinal curvatures [23]. Studies have shown that children habitually slumped or when were asked to relax. There was a reduction in lumbar lordosis [17,24] and thoracic kyphosis [24]. The reduction in thoracolumbar lordosis did not differ significantly between AIS patients and normal children [25] in relaxed sitting, erect sitting, or crossed-leg sitting.
When asked to sit in their habitual position, normal children aged 11-13 sat with a loss of lumbar lordosis [24]. The 19 AIS patients evaluated by Gram and Hasan [18] had a similar sitting pattern. Yet, van Loon et al. [26] found that AIS patients tended to sit with a more marked loss of thoracolumbar lordosis. This may be related to the marked neuromuscular tightness in AIS patients [27].
Though the spinal sagittal profile does not differ significantly between AIS adolescents and normal controls, there are marked differences in the frontal plane. When asked to sit relaxed, the majority of AIS children lean to one side [25]. Using infrared markers and a camera to study the sitting postures of 19 AIS patients, Gram and Hasan [18] found that the subjects tended to lean to one side when seated in a relaxed pose. The lean was curvetype dependent, differing in single and double scoliosis curves. In single thoracic and lumbar curves, the subject tends to lean laterally to the side of convexity. The lean which was defined as the horizontal distance between S1 and a perpendicular line from C7 in the frontal plane, averaged 1 cm. The distance of the lean was smaller in double curves. In relaxed sitting, the lean was towards the concavity of the lumbar curve [17] in the presence of a double curve. Similar findings were reported by Drza-Grabiec et al. [24]. They filmed 91 normal children aged 11-13 in their natural relaxed sitting postures, and found marked asymmetry in their relaxed sitting postures; also, the angular value of existing scoliosis increased after prolonged sitting [24]. AIS patients with thoracolumbar curvatures were reported to have increased scoliosis when sitting [25].

Standing postures
Standing is inherently associated with an increase in spinal curvature, as a result of gravitational forces. Clinical observation showed that AIS patients tend to bear weight on one side [16]. When standing, the spinal curvature increases when compared to relaxed and erect sitting [17].

Carrying A backpack
Regular carrying of schoolbags and backpacks can affect the spinal curvature. The effects depend on the mode of loading, the weight of the carriage, and the side of the loading. Carrying the bag on one shoulder, across the body and on the back affect the spine in different ways [28][29][30][31][32]. These findings are minimally important because children spend far less time carrying a backpack; however, they are conceptually important when considering the role that postural re-education has on the spinal configuration.

Scoliotic breathing pattern
Lehnert-Schroth [16] described the scoliotic breathing pattern. This asymmetric breathing pattern may be caused by faulty breathing mechanics. In right thoracic scoliosis, the right dorsal area is convex and the left is concave. Ventrally, the opposite is present. The right anterior chest is concave and the left anterior chest is convex. During breathing, forces are directed in the direction of convexi-ties, i.e., to the right posterior thoracic area and the left anterior thoracic area. This tends to rotate the thorax.
In thoracic scoliosis, the lung in the convex side is larger than the counterpart in the concave side, which is more compressed. With inhalation, which is an active process, air fills both lungs. The lung on the convex side, being larger and less compressed, tends to be more inflated than the lung on the concave side. During exhalation, which is a passive process, air is expelled from both lungs. As a result of increased chest wall elasticity, more air is expelled from the concave side. The results are that the size differential of the lung increases with each deep breath. There is a possibility that this dysfunctional breathing pattern, if performed regularly, may be a factor that contributes to increased rotation and progression of spinal curvature [16]. Rehabilitation of the scoliotic breathing pattern is an essential component of Schroth scoliosis exercise, one of the programs discussed in this review, which also incorporates postural re-education for the management of AIS.

Materials and Methods
PubMed searches were performed using the key words 'scoliosis, exercise, scoliosis-pattern-specific-exercises (SSE), physiotherapy, rehabilitation, active self-correction' to identify studies on the use of physical exercises, scoliosis-pattern-specific exercises and physiotherapy in the treatment of AIS. The studies are reviewed to ascertain if the treatment outcome support the use of scoliosispattern-specific exercises and postural rehabilitation in the management of AIS in growing children.
A study, using FITS exercises on patients with AIS with an average age of 11.9, Risser 0-2 and single scoliosis curve measuring 17.7°, showed that 50% of the patients had the curves improved, 46.2% stabilized and 3.8% worsened [39]. For patients with double scoliosis, the outcome was similar though a smaller percentage of curves stabilized. In this group of patients, 50% improved, 30.8% stabilized and 19.2% of the cases worsened [39].
Dobomed exercises, when used in combination with Chêneau bracing for an average period of 43±9 months were found to stabilize progressive thoracic scoliosis in 89% of the AIS patients [48]. 11% of the patients progressed to surgery [48]. In an earlier study, the average Cobb angle of 152 AIS patients aged 14.2 years increased from 25.92° to 31.04° after a treatment period of 31.8 months [49].
Side-shift and hitch exercises which are specifically targeted to reduce thoracic, thoracolumbar and lumbar curves respectively by laterally shifting to the side of concavity were also shown to stabilize scoliotic curves, together with part-time bracing [34]. Of the 328 patients treated, 308 patients with an average age of 13.9 and initial Cobb angle of 31.2° performed regular side-shift and hitch exercises, together with part time bracing whenever indicated, were followed up to the average age of 18.6. The Cobb angle at the conclusion of treatment was 32.6° [34].
SEAS has also been shown to be able to stabilize mild scoliotic curves [37]. The treatment outcome of a group of AIS patients treated by SEAS was compared with that of the control group treated by general physiotherapy treatment provided by individual therapist. The average age of the treatment group was 12.7, with Cobb angle of 15.3° and ATR of 8.9°, with the control group having similar age and curve severity. After performing SEAS.02 for one year, one patient (4.3%) in the treatment group progressed and required surgery. In the control group, 5 patients (20%) progressed to surgery. Based on a change of 5° Cobb angle as a reference for improvement or progression of the curvature, 28.9% of the patients in the treatment group improved, 68.4% were stable and 2.7% became worse. In the control group, 5% improved, 82.1% were stable and 12.9% became worse. Basing on a change of 2° ATR as a reference for improvement or progression of spinal curves, 30.4% improved in the treatment group, 56.5% were stable and 13.1% became worse. For the control group, 36.4% improved, 36.3% were stable and 27.3% became worse [37]. One randomized-controlled study compared the effects of active self-correction and task-oriented spinal exercises with general exercises in patients with mild AIS, with Cobb angle of less than 25° [43]. Outcome measures one year later showed that the training in the intervention group led to a significant improvement (decrease in Cobb angle of 5°), whereas the control group remained stable [43]. Thus scoliosis-pattern-specific exercises are superior Table 2. Some of the corrective postures that should be adopted during daily activities in patients with idiopathic scoliosis

Activities of daily living a)
Position of the pelvis Corrective movement to traditional exercises, which are unspecific exercises in reducing spinal deformities in patients with mild AIS [43]. Schroth scoliosis in-patient rehabilitation (SIR) has been used in the treatment of AIS for many decades [16,35]. SIR was found to improve curvatures of patients with AIS [33]. One hundred and seven patients with AIS, with an average Cobb angle of 43.06°, were treated by an in-patient exercise program. After 4-6 weeks of treatment, the average Cobb angle reduced to 38.96°. An improvement of 5° or more was found in 43.93% of the patients, 53.27% were unchanged and in 2.8% the curve increased by 5° or more. The improvement in Cobb angle was highly significant [33]. Schroth scoliosis in-patient rehabilitation was also found to significantly reduce the progression risk of patients as compared to age and sex-matched controls [35]. Also, SIR was also found to reduce right heart stress [50], improve vital capacity [45] and improve muscle balance in patients with AIS [51].
A cohort study in Turkey similarly showed improvement in Cobb angle, vital capacity and muscle strength of patients with AIS, undergoing Schroth therapy on an outpatient basis [36]. Fifty patients with an average age of 14.15±1.69 were instructed to perform 4 hours of exercises every day for 5 days consecutively for 6 weeks. They were thereafter advised to perform the Schroth exercises at home. After one year of the exercises, the Cobb angle reduced from an average of 26.1° to 17.85° [36]. The vital capacity increased by 15% in one year. There was an increase in muscle strength and recovery of postural defects in all patients [36].
The increase in back muscle endurance has recently been confirmed by a randomized-controlled study, which compared one group of AIS patients treated by Schroth exercises in addition to standard care with another group of patients treated by standard care alone [52]. Addition of Schroth exercises significantly increased the back muscle endurance and reduced the SRS-22r pain score [52] at different follow-up periods.
Noh et al. [46] compared a novel spinal corrective technique (CST), based on Schroth exercises and core stabilization techniques with conventional physiotherapy exercises in the management of AIS. CST resulted in greater improvement in Cobb angle and vertebral rotation when compared to general exercises in the group of patients aged between 10-19. Also, CST improved the pelvic incidence to normal range. Yet, the method did not improve the sagittal profile [46].
The effectiveness of Schroth exercises in AIS was reported in another randomized controlled trial [44]. Fortyfive patients with AIS were randomized into three groups, each with 15 patients. The intervention group performed Schroth exercises under physiotherapist supervision for 6 weeks and continued to do the exercises at home. The second group did the Schroth exercises at home, after they were taught the exercises by a physiotherapist. The third group was treated by observation. At the conclusion of the study at 24 weeks, evaluation showed that the Cobb angle and angle of trunk rotation improved significantly in the intervention group, when compared with the other two groups [44]. This suggested that scoliosis-pattern-specific exercises are superior to observation in the treatment of AIS [44].
The newest branch of Schroth, Schroth Best Practice, was introduced in an attempt to improve the time efficiency of rehabilitation [15]. Furthermore, postural reeducation was integrated in the form of ADL training into the Schroth Best Practice program, something that was not a major component of the original Schroth treatment program [15]. The addition of ADLs is important to ensure that postural control is not lost throughout the day. Without integrating the corrective ADLs, the spinal curve(s) continues to be loaded asymmetrically during daily activities, making improvement via exercise more difficult [15]. Another addition to the program focused on maintaining or improving the thoracolumbar natural curvature. This was found to decrease the lateral deviation of the trunk as well [53]. A pilot investigation showed that four days of treatment could reduce the ATR significantly [38] in patients with an average age of 14 and average Cobb angle of 46°. The ATR reduced from 10.3° to 8.2° after 4 days of treatment. The improvement in outcome is similar to that which can be achieved in 3-4 weeks of inpatient rehabilitation. This was subsequently confirmed by two studies [40,42]. In additional studies, Schroth Best Practice has been shown to reduce Cobb angle [42] and other signs and symptoms of AIS [41].

Discussion
There have been many studies proving that scoliosis-pattern-specific-exercises improve or stabilize scoliotic curves in patients with AIS [37][38][39][40][41][42]. A systematic review in 2008 concluded that SSE was effective in the treatment of AIS [54]. A Cochrane review in 2012, however, concluded that there was insufficient evidence in support of the use of exercises in the treatment of AIS [55]. Nevertheless, since the publication of the review, four controlled outcome papers on the effects of scoliosis-specific exercises on AIS have been published [43,44,46,52]. Three were randomized controlled trials [43,44,52] and one was a controlled trial [43]. The significance of this, collectively, is that there is a proactive approach to improving scoliosis, beginning as early as the observation phase.
When scoliosis progresses to a Cobb angle of or exceeding 45°-50° in growing children, spinal fusion surgery is often recommended. This is because curves greater than 50° at skeletal maturity are reported to progress an additional 20°-30° over the subsequent 30-40 years period [56,57]. Despite this, a long-term follow-up study of untreated patients with AIS has shown that the consequences of AIS over a lifetime are minimal, sometimes moderate in more severe cases, and very rarely life threatening [3,4,7,14,56]. Recently, a study showed that the SRS-22r scores of non-operated and operated groups of AIS patients were similar, which implied limited benefits of surgery [58]. In view of the relative benign nature of AIS [58] and the long-term complications of surgery [59][60][61], it may be necessary to review the current indications for treatment of AIS.
It is evident that there are many different approaches to the treatment of AIS. Not all scoliosis exercises are equally effective [62]. The principles of their correction are different. Some use general exercises without a defined correction procedure (Dobomed), while others mainly aim at specific curvature correction (Fig. 1) (side-shift, self-correction exercises, SEAS, Schroth, and Schroth Best Practice). Also, because the demographics and curve severity of study populations and the outcome measures have been different, direct comparison of the effectiveness of the varied approaches is impossible.
Among these methods, the Schroth approach is the only one that has been proven to be effective in three controlled trials [44,46,52], two of which were randomized [44,52]. An updated version, Schroth Best Practice, evolved out of the original Schroth method to provide an all-encompassing postural rehabilitation program for  the management of AIS. The exercise approach has been simplified ( Fig. 2) with added incorporation of sagittal plane correction and scoliosis-pattern-specific activities to daily living (ADLs) (Fig. 3) into the program [38]. Sagittal plane correction has been found to decrease the lateral deviation of the trunk as well [53]. Of particular significance is the incorporation of ADLs (Figs. 3, 4) in the management of AIS, as it was reasoned that thirty minutes of SSE daily is unlikely to improve curvature if the patient does not adopt proper posture during daily activities. Training scoliosis patients on how to avoid loss of postural control during everyday activities can improve outcomes. This is because scoliosis curve-pattern-specific ADLs take into account the pelvic shift and the types of scoliosis curves to unload the curve. Without integrating the corrective ADLs, the curve(s) are loaded during the course of the day making improvement via exercise more difficult [7].
Studies have shown that this simplified approach (Schroth Best Practice) does not compromise the outcome of the exercise program [42,44]. These updated methods of postural re-education (Fig. 4) offer the potential for improvement above and beyond the original Schroth program [42]. They also address other signs and symptoms of scoliosis as recognized in independent studies [40][41][42]. Patients are also able to achieve comparable results within one week or less, as opposed to the longer durations with traditional in-patient rehabilitation [38]. In the study by Lee [42], in the subgroup of patients with larger curvatures (>30°), the Cobb angle corrected about twice as much as during in-patient rehabilitation in a comparable sample of patients.
Although there is Level 1 evidence for the Schroth approach and active self-correction, the evidence cannot be extrapolated to include every type of SSE, as the principle and dosage of each treatment approach differ. Studies need to be conducted to compare the effectiveness of different approaches using cohorts of similar demographics, curve severity and outcome measures, before the Level 1 evidence can properly be assigned to different exercise approaches.
Schroth Best Practice evolved out of the original Schroth program and includes principles of the original Schroth approach, as well as task-oriented exercises and active self-correction [43]. Since the outcomes are comparable or better than the original Schroth method, this program can be regarded as having Level 1 evidence.

Limitation
The three independent studies on Schroth Best Practice have their limitations. Two of the papers [40,42] were

A B
prospective short-term cohort studies. The studies included patients who were relatively skeletally mature. The average age of patients in one study [40] was 13.7 years of age and that of another [42] was 16 years of age. Also, the period of intervention was short. One study involved exercising for 7 days [37] and another for 2.9 months [42]. Also, there was no follow-up of the patients until 5 years after skeletal maturity. The third study [41] evaluated patients before and after 6 weeks of the exercises using optical topography, electromyography and stabilometry. Whether the improvement in outcome can be maintained over a longer period of time, however, has not been investigated. Also, whether adoption of corrective postures in daily activities does reduce the asymmetrical loading of the scoliotic spines and the resultant spinal deformities remain to be studied. Thus while Schroth Best Practice should be incorporated in clinical practice, further studies are required to validate its individual components.

Conclusions
Postural rehabilitation using scoliosis-specific exercise can be effective in the treatment of AIS patients when incorporated into daily life. For the benefit of the patient, it should be integrated into the existing management of the condition. Schroth scoliosis exercises and active selfcorrection have both been validated by Level 1 evidence. Whether this evidence can be extrapolated to include other forms of scoliosis-pattern-specific exercises requires further investigation.

Conflict of Interest
HR Weiss is receiving financial support for attending symposia and receives royalties from Koob GmbH & Co KG. The company is held by the spouse of HR Weiss. None of the other authors report any competing interest or potential conflict of interest.