Research quality in scoliosis conservative treatment: state of the art

There are some methodological points that must be raised in the attempt for new effective
conservative treatments able to reduce the burden of therapies on young patients 9], 20]. In fact, while sound research will convince even the skeptics, biased studies can
damage the entire field of conservative scoliosis treatment. Physicians and allied
health professionals in the field want to shift their treatment to provide the most
effective ones possible, but biased research does not allow this evolution. Therefore,
there are some criteria that should be followed in order to collect reliable and useful
data.

Inclusion criteria

Idiopathic scoliosis is not only a matter of posture, but it’s a three dimensional
deformity of the spine and trunk 20]. The criteria to define scoliosis requires a coronal curve larger than 10° Cobb Angle,
the presence of vertebral rotation in the radiograph and the presence of a rib hump
consistent with the curve (measured through the Angle of Trunk Rotation – ATR, or
Angle of Trunk Inclination – ATI) 1], 20], 23]. If postural scoliosis 24], 25] (that, in fact, is not scoliosis) is confused with true structural scoliosis, then
treatments are proposed for healthy children and good “results” are obviously achieved.
Some studies clearly report that they are dealing with postural scoliosis, but a less
sophisticated reader can be confused 24], 26]. Also, other studies include curves less than 10° 27], 28], or fail to report data about the ATR 29], and this can be misleading to the reader too.

Other possible limitations of the interpretation of treatment result rely on the inclusion
of a mixed population 27], 29]: chronological criteria for scoliosis classification should be followed, and patients
should be divided according to the age at diagnosis and scoliosis type (idiopathic,
secondary, congenital, degenerative).

Outcome measures

The main outcome measures for scoliosis have been clearly pointed out 20], 30]. They consist of quality of life assessment, aesthetics, radiographic parameters,
ATR/rib hump measurement, and sagittal profile. Papers not reporting these outcomes
and claiming improvement of scoliosis cannot be used as pragmatic and appropriate
references.

Inappropriate follow-up

A serious approach to scoliosis during growth must show its effectiveness in the medium
term and not only in the very short term. If the results are very short term 27], 29], 31], then the study must be called “preliminary” or “pilot”. No conclusions about final
results can be drawn from studies with such a short follow-up other than the indication
to go on with further research. One month or 3 month results are useless to reach
reliable conclusions on efficacy and 6–12 months of treatment can only show a trend
that must be then confirmed with end growth results and possibly a further follow
up during adulthood.

Interpretation of findings

Conclusions must be supported by the data. This sounds obvious, but frequently in
all fields of medicine, and also in scoliosis research, there is an overestimation
of findings, with statements of effectiveness going beyond what the data actually
show 25], 27]. Moreover, if the methods are not sound enough to gather any good evidence, the conclusions
are sometimes totally misleading. And this is the real problem; claiming results that
have not been proven.

Skeletal maturity

Scoliosis progression during growth depends on the stage of bone maturation. Despite
its limits, the Risser sign is today the gold standard for such an evaluation, and
must always be reported in every paper 32]. This sign is important for inclusion criteria and for appropriate follow up. The
most risky period for AIS is the growth spurt of puberty, during which the Risser
sign changes from 0 to 2. The SRS criteria for bracing studies focused mainly on this
phase 33], and skeletal maturity must be reached before the end of treatment to determine the
success of the treatment 34].