A Review of the Literature on Adolescent Idiopathic Scoliosis (AIS)

Review Article

Austin Phys Med. 2019; 2(1): 1006.

A Review of the Literature on Adolescent Idiopathic Scoliosis (AIS)

Bernardino S*

Department of Orthopaedic and Trauma Surgery, Asl Bari, Italy

*Corresponding author: Saccomanni Bernardino, Department of Orthopaedic and Trauma Surgery, Asl Bari, Italy

Received: September 20, 2019; Accepted: October 23, 2019; Published: October 30, 2019


Objective and Summary of Background Data or AIMS: Scoliosis is characterized by three-dimensional changes of the spine and is estimated to be present in 4% of the population worldwide. The most common form is the adolescent idiopathic.

Methods: The purpose of this study is to identify the major muscle abnormalities found in patients with adolescent idiopathic scoliosis through a literature review. We conducted an electronic search of the national databases PubMed, Lilacs, PEDro, and EMBASE using the keywords “scoliosis”, “biomechanics”, “exercise”, “physical therapy specialty”, “idiopathic”, and “muscles”, from January 2003 to April 2015.

Results and Conclusions: The most relevant articles in English, Portuguese and Spanish and Italian were selected by title and abstract. It was also performed a manual search of the references of the selected articles. From a total of 4,319 articles, 11 were selected. We conclude that individuals with AIS have changes in the paraspinal muscles, with a difference in activation between the concave and convex sides, suggesting an increase in EMG activity on the convex side, although there is still no consensus among the authors.

Keywords: Scoliosis, Biomechanical phenomena; Adolescent; Exercise


It is present in approximately 4% of the world population and 70-80% of cases are idiopathic in origin, that is, without any specific etiology [1-20].

Among the types of idiopathic scoliosis, the most common is that of the adolescent [AIS], which affects individuals during the growth period from 10 to 18 years of age,1-10 being more common in females. With no definite etiology, various studies have suggested that it is multifactorial, with hypotheses that range from genetic and hormonal influences, changes in the nervous system, and deficient postural control to changes in the cartilaginous tissue and intervertebral discs, abnormalities in the growth of bones and the spine, biomechanical and activity changes, and changes in the length of the paraspinal musculature [2], [8], [20-22].

The treatment of AIS depends on the magnitude of the curve, which is classified according to the angulation. Values between 10º and 20º/25° are considered mild and the indicated treatment is physical therapy or observation. Curves between 20º and 40º/45° require the use of braces and physiotherapeutic treatment. Finally, values above 40º/45º are indicated for surgical treatment [6].

Specific exercises are widely used in Europe for the treatment of AIS and are promoted by various schools, unlike in the American countries where this practice is not so widespread [23-25].

The treatment of [AIS] is basically divided into conservative and surgical approaches, with weak evidence for conservative treatment with conventional physiotherapy and stronger evidence for the use of braces or surgery when indicated [1,6,8,9,15,23,25].

Among the factors suggested as causes of the disease, the muscular factor is a subject of intense research as both a cause and a consequence of the deformity, but there is still no consensus as to whether the paravertebral musculature directly influences the beginning and the progression of scoliosis or whether the changes found in the fibers, strength, and electromicrographic activity are characteristics secondary to the deformity [2,22,23].

AIS, in addition to being characterized by three-dimensional changes in the spine, presents changes in the positioning and biomechanics of other segments, visible in the physical exam, such as change in the positioning of the shoulders, shoulder blades, and pelvis, which are related to the progression of the curve and may suggest that the musculature involved in the work of these structures is compromised, whether from compensation for the changes imposed by the deformity or as a result of the structural changes themselves [1-10,19].

The number of structural changes found in these patients makes us think about their influence on normal biomechanics and about the consequences for muscle function.

It is not known for certain to what point the scapular and lower limb muscles suffer as a consequence of the structural changes imposed by [AIS] or how the paraspinal musculature participates in the development and progression of the curve. We only know that the changes are there and that it is hard to say how and why they manifest themselves.

The objective of this study was to identify the principal muscular changes found in patients with adolescent idiopathic scoliosis through a review of the literature.


We performed an electronic search of the PubMed [Public Medline], LILACS [Literatura Latino-Americana E Do Caribe Em Ciências Da Saúde], [Latin American and Caribbean Health Sciences Literature]),

PEDro [Physical Therapy Evidence Database], and EMBASE [Biomedical Data Base] data bases using the keywords “scoliosis”, “biomechanics”, “exercises”, “physical therapy”, “idiopathic”, and “muscle”, previously consulted in DeCS [Descritores em Ciências da Saúde] [Health Sciences Key words] and MeSH [Medical SubjectHeadings].The keywords were combined using the Boolean operator “and” a search of works from the period of January 2003 to April 2015 was performed to identify clinical trials and prospective crosssectional and cohort studies about the proposed subject.

Following selection of the articles by electronic search, a manual search of the references of the chosen articles was conducted to avoid losing any articles that were relevant to the study.

The inclusion criteria adopted were language (English, Portuguese, and Spanish), target population (adolescent), etiology (scoliosis of idiopathic origin), type of study (except case studies), species (human), and archives from the period between January 2003 and April 2015.

Studies that involved surgical treatment, the administration of medications, studies of cadavers, comparative studies or orthoses, software analyses, studies that did not discuss the muscular changes found in adolescent idiopathic scoliosis, articles about respiratory changes, sensory motor response, changes during walking, and the application of specific treatment protocols were excluded.


With the combination of the words ‘scoliosis’ and ‘biomechanics’, 302 articles were found: two in LILACS, 157 in PubMed, and 143 in EMBASE in five journals and none in the PEDro data base. Only two articles, from the PubMed database, were selected. By combining the words ‘idiopathic’, ‘scoliosis’, and ‘exercises’, 25 articles were found: 240 in PubMed, three in LILACS, and 13 in PEDro. EMBASE did not return any articles in the search, but only books. Four articles were selected from the PubMed data base. The search using the keywords ‘scoliosis’ and ‘physical therapy’ returned 1056 articles:, seven from PEDro, 946 from PubMed, 71 articles from three EMBASE periodicals, and 30 from LILACS.

Two of the PubMed and one of the LILACS articles were chosen. The last search was performed combining the keywords ‘scoliosis’ and ‘muscle’ and returned 2707 works: 1104 from the LILACS data base, 28 from PEDro, and 1532 from PubMed. Once again, EMBASE returned only 13 books. Only two of the PubMed data base articles were selected (Table 1). The final total of works selected was 11, as no relevant works were found by the manual search (Table 2) and (Figure 1).