REVIEW OF ADVANCES IN COBB ANGLE CALCULATION AND IMAGE-BASED MODELLING TECHNIQUES FOR SPINAL DEFORMITIES
V. Giannoglou
a,
, E. Stylianidis
a
School of Urban-Regional Planning and Development Engineering, Aristotle University of Thessaloniki, GR 54124 - vgiannoggmail.com
a
School of Urban-Regional Planning and Development Engineering, Aristotle University of Thessaloniki, GR 54124 - sstylauth.gr
Commission V, WG V5 KEY WORDS: Scoliosis, Spine, Cobb angle, X-rays, 3D model, Image based techniques.
ABSTRACT: Scoliosis is a 3D deformity of the human spinal column that is caused from the bending of the latter, causing pain, aesthetic and
respiratory problems. This internal deformation is reflected in the outer shape of the human back. The golden standard for diagnosis and monitoring of scoliosis is the Cobb angle, which refers to the internal curvature of the trunk. This work is the first part of a post-
doctoral research, presenting the most important researches that have been done in the field of scoliosis, concerning its digital visualisation, in order to provide a more precise and robust identification and monitoring of scoliosis. The research is divided in four
fields, namely, the X-ray processing, the automatic Cobb angles calculation, the 3D modelling of the spine that provides a more accurate representation of the trunk and the reduction of X-ray radiation exposure throughout the monitoring of scoliosis. Despite
the fact that many researchers have been working on the field for the last decade at least, there is no reliable and universal tool to automatically calculate the Cobb angles and successfully perform proper 3D modelling of the spinal column that would assist a
more accurate detection and monitoring of scoliosis.
Corresponding author
1. INTRODUCTION
Scoliosis is defined as the greater than 10 degrees curvature of the spine, as measured on an X-ray. Anything less is considered
to be normal variation. The most common type of scoliosis, idiopathic scoliosis, has no specific identifiable cause so far.
Around 2 of the people are diagnosed with scoliosis worldwide, whereas if a family member is diagnosed with
scoliosis, other members have percentage as high as 20 to develop scoliosis Department of Orthopaedic Surgery,
http:orthosurg.ucsf.edupatient- caredivisionsspineconditionsdeformityscoliosis,
which comprises strong evidence that it is inherited. Scoliosis is found
at any age, but it is most common in children over 10 years old. Scoliosis can be treated and healed: treatment aims at improving
the health and the aesthetics of the patients and it is of paramount importance for the health and self-esteem of
juveniles. If the doctor suspects a scoliosis case, after measuring the trunk
asymmetry with the scoliometer, an X-ray of the back will be taken, from which the doctor measures the Cobb angle, which is
the golden standard to quantify and grade scoliosis. Being manually executed, Cobb angle calculation entails subjectivity,
errors and it is time consuming. Considering the severity of scoliosis, authors gathered the most
important researches in various fields of the subject, pointing out their strengths and their weaknesses, so that other
researchers, as well as the authors themselves, can have a solid ground from where to begin their works.
The most reliable means of identifying a scoliotic patient is the X-ray, therefore the initial field of the review is the X-ray
processing. With the development of image processing procedures, X-ray images have also been affected, exhibiting
some very appealing methodologies to cope with, as it will be explained in more detail later.
Another very crucial field in the advances of spinal deformities is the Cobb angle. Being the current golden standard, it is
important to be accurately calculated and other researchers strove in finding computerised methodologies to do so as it will
be presented in the main part of this work. As the Cobb angle is a 2D measurement of a 3D deformity, it is
not the best indicator of the severity manifested in external appearance. The 3D representation of the human spinal column
that would successfully depict the real nature of scoliosis is a field that contains tons of work done. To this end, many
researchers occupied themselves to develop methodologies for 3D representation of the spine.
While all the above mentioned efforts have distinctive characteristics that make them valuable to the scientific
community of scoliosis, what is missing is a uniform platform that encompasses all the above features, providing an inclusive
tool that is able to perform all the necessary actions spine detection, Cobb angle calculation, 3D model of the spine in
order to provide maximum insight for the caretaker of the patient. Authors reckon that a platform like this is the next step
based on all the advances that were reviewed in this work.
This contribution has been peer-reviewed. The double-blind peer-review was conducted on the basis of the full paper. doi:10.5194isprsannals-III-5-129-2016
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Since this work is part of a post-doctoral study, the reviewed papers are oriented towards the research goals of the
aforementioned study. It is well understood that are plenty more interesting sub-fields in scoliosis subject, but it would be
impossible to present all the related studies in a limited space research paper.
The rest of the paper is organised as follows: Section 2 is the main part of the present work, including all the paper reviews
that comprise the basis of knowledge for the future work. In particular, subsection 2.1 analyses X-ray processing techniques
that constitute the first step for detecting spinal deformities in human back. Subsection 2.2 elaborates on the findings
concerning Cobb angle detection in literature. Subsection 2.3 deals with the 3D reconstruction of the spinal column
techniques and subsection 2.4 focuses on scoliosis assessment techniques that include less or no radiation at all. In section 3
there is a discussion on the findings presented in this paper and also refers to the potential work that could commence from the
aforementioned findings.
2. LITERATURE REVIEW
