Scoliosis: extract (1) of an interview with Professor

Scoliosis: extract (1) of an interview with Professor Paolo Raimondi on pathological vertebral
rotation. Relationship between the assessment of vertebral rotation measured with a
Formetric scan and that measured using the Raimondi method. By A. Di Michele
Keywords: scoliosis, vertebral rotation, Formetric
With the view of looking into the problems of vertebral rotation in scoliosis more in depth, I have
accompanied Professor Raimondi during the course of his university degree (Faculty of Sport
Sciences, Department of Engineering for Mechanics, Energy and Management at the University of
L'Aquila) and have been able to witness a great many measurements taken through various types of
x-ray and imaging systems. Over this lengthy period of time (the work on the research thesis
continued for approximately two years), I had opportunities to ask him many questions that arose
out of either doubt or curiosity. I was able to join a few conferences on the Raimondi measurement
methodology, and many questions were resolved. Consequently, with my questions answered, my
doubts cleared and my curiosity satisfied, I was introduced to a "mathematical world" that led me to
conclude that the "Raimondi method" is infallible if applied according to the research results that he
has carried out and using only the raw data collected in the various manuals. However, it is not free
from mistakes (as he continuously reminds us) due to the mathematical mean of the data gathered to
produce a small table or rule for quick consultation. My questions and answers were thus adapted
during the drafting of the chapter, through which the difficulty of the research method can be
understood.
Q: What is the difficulty in measuring vertebral rotation accurately?
A: The measurement of vertebral rotation nowadays is not difficult using the current technologies.
However, measuring pathological vertebral rotation is more complex. Current radiographic
technologies, x-graphics, tomography, xerography, stereo radiography, etc., cannot give accurate or
approximate measurements of pathological rotated vertebrae, because these present great and
diverse deformities and spatial alterations in the case of grave scoliosis. Furthermore, vertebral
rotation--particularly pathological vertebral rotation, where the rotation must be measured in
relation to the vertical rotation axis--does not rotate following the accepted standards. Moreover, we
know the physiological rotation of a vertebra and the stages it goes through, but we don’t know how
the moment of a deformed vertebra varies and how the rotational axis develops in relation to its
angle. No technology has been able to assess the actual spatial positioning of a deformed vertebra,
nor the angle of its vertical axis. We know very well that, in order to assess the rotation of a
vertebra, we must know exactly how its vertical axis is positioned in space. All the technologies
available today, including three-dimensional imaging, assess the vertebra by considering only one
of its aspects. However, this is merely an image that is hypothesized by the computer. I know of
various works on the three-dimensional imaging of scoliotic curves and vertebral rotation,(2-23) but
each work originates from a reconstruction and therefore shows all the inaccuracies of such
reconstruction. The group that studies bioengineering applications in the Department of Mechanical
Engineering of the University of L'Aquila has devised a three-dimensional model of the spine, but
only after many years of study. This 3-D model that reproduces the spinal movement, with its
deformities in the case of hunching, is still not exhaustive in view of discussed above, even though
it has yielded remarkable results.
Q: How did you initiate the idea of devising a method to measure vertebral rotation?
I started developing my interest in scoliosis rehabilitation in 1968. At that time, little was known
compared to now, and I am not aware of methods available to measure vertebral rotation in
scoliosis. We used the traditional Fergusson(24) method to measure the degree of curvature, but that
didn’t provide accurate readings for curvatures in excess of 50°. Subsequently, the Scoliosis
Research Society devised the Cobb method as a standard of measurement. This method, like
anything else, has its merits and faults. One cannot measure the curvature itself with the Cobb angle
but can only measure the inclination of the upper- and lower-limit vertebrae. Unfortunately, that can
create a false picture of the curvature. As a matter of fact, the inclination of an upper- or lower-limit
vertebra can’t represent the overall change in curvature. The measurement of the vertebral rotation
was certainly studied by Nash and Moe.(25) The study was carried out on thoracic and lumbar
sections using shadows with known rotational increments as landmarks, which highlighted, among
other things, the measurement differentiation between the spinous process and the pedicle. By
combining the two parts of the study, the authors proposed a simplified method for the assessment
of vertebral rotation as a relationship between the pedicle movement and the degrees of rotation. It
was in 1975 that I read the work by Nash and Moe and realized that this method, despite its
suitability relative to that day and age, was approximate in that the measurements were taken using
the radiographic shadow movements of the convex pedicle (which moved toward the cavity of the
scoliotic curve), which was given a rotational value determined by the sections into which the
vertebra had previously been divided. In 1975, I started to think of new, more accurate solutions to
measure vertebral rotation because, even if the Cobb angle was important, the evaluation of
scoliosis also had to consider the vertebral rotational value. Indeed, only the pathological rotation of
the vertebrae and their warping change the direction of weight distribution and moments of the
vertebrae themselves with the subsequent indentation, worsening and collapse of the spine. After
all, in a rehabilitation environment I saw x-rays of scolioses cases with mild curvatures that did not
show any vertebral rotations or any deformities of the vertebral body. However, I also saw severe
curves that consistently presented such rotations and deformities. During that period, I met a
pathologist-anatomist with whom I discussed the issue. He had formerly conducted autopsies and
therefore provided me with two spines--one of which was scoliotic--and a couple of teaching plastic
ones. His advice was very useful. The study to find a simple methodology by which to measure
vertebral rotation was carried out between 1975 and 1985 and was then presented at the World
Conference International Council for Health, Physical Education and Recreation, at Cuneo in 1986.
Q: How was the method devised?
A: We had many difficulties and very high costs. Along with the two original spine samples, we
used many teaching spines, from which I cut out individual vertebrae and created deformations by
indenting them. Initially, the theoretical problem pertained to defining the rotation axes and taking
into account the axes of individual vertebrae as well as the axes of various segments from the spine,
because the axis of rotation of a vertebra is also correlated to the topographic location of the spine.
Other difficulties resulted from the rotation difference between the vertebrae, particularly the
lumbar ones due to their "bean"-like structure. Additionally, the anatomical indications of the texts,
which reported various degree of rotation that the vertebrae could undergo, didn't quite match: More
specifically, they would match if the vertebrae weren’t deformed. However, once a vertebra was
deformed there wasn't any correspondence and all the parameters changed. For example, if a
thoracic physiological vertebra, at the T6/T7 level physiologically rotates at about 8°, it rotates
differently if it is indented or rather deformed. For example, if the line of the thoracic vertebrae has
a rotation range of about 70°, when you measure the same line with deformed vertebrae, the degree
of rotation don’t match. In all of the works I’ve studied, as written by various authors, the
researchers would perform the measurement with physiological vertebrae. There are few authors
who correlated the five basic parameters to each vertebra (on which my method is based), namely
the orientation of the vertical axis, the diameter of the vertebral body, the trocosi of the posterior
arch, the shift of the vertical axis of the pedicle and the vertebral deformation.
(Fig. 1)
The images presented by various authors in the study of vertebral rotation always show the rotation
of a normal vertebra on a plane (Fig. 1).
One can rarely observe the rotation with various modifications of the
vertebra and of the three-dimensional orientation or of the elective
rotational plane. This is not good, because a deformed vertebra,
although it rotates around its vertical axis, is closely related to the
horizontal plane, which in this case is oblique; because the
deformation of the posterior arch, changing the articulated relationship
between the facet joints and therefore the direction of rotation, changes
the rotation of the vertebra with respect to a physiological vertebra;
because the lateral inclination of the vertebra acts on the rotative
capacity, given that the different geometrical constitution of the facet
joints allows for infinite rotating possibilities; etc.
(Fig. 2)
One aspect is to calculate the rotation of a healthy vertebra, which rotates on a perfectly even
vertebral level. Another aspect is to calculate the rotation of a vertebra that rotates on an uneven
vertebral level, as is the case of a deformed vertebra. In this case, the tangential rotating slide occurs
on an uneven, deformed surface, which may present multiple conformations. In such cases, for
some degree of rotation the vertebra can perform the rotating slide on a horizontal surface or, for
some degrees, on an inclined surface by changing its axis of rotation (Fig. 2). This changes the
vertical axis of rotation, meaning the rotation itself as well as the value of rotation. In fact, for the
same movement on a horizontal plane (from x to y) of a vertebra whose rotation level is even and a
vertebra whose level is uneven, the value of rotation, the inclination of the vertical axis and the
inclination of the horizontal axis are not the same, just as the degree of rotation can’t be the same.
Besides the difficulties I've just mentioned, others pertain to manipulating the vertebrae in order to
deform them, wedge them and make their rotation plans crooked. There was the difficulty of
sectioning the pedicles and getting to their roots, and of tracing the major axis of the pedicles with
great precision and inserting a very thin hot sheet as an extension of the axis and a guide in order to
detect the very small rotational movements. It has also been very difficult to correlate the degree of
rotation with the linear movement, having to measure them in millimeters with a ruler or boards, on
a plane. Other challenges emerged through the research of technicians who were able to build the
rotation device, finding the micro-motors that could rotate the vertebra in a micrometric way,
searching for centesimal protractors, collecting and processing data, and then presenting them in a
practical way and other things that are difficult to recall. In conclusion, I've destroyed two
anatomical columns and a dozen of educational columns.
Q: As for the data, how was the ruler set up (or the boards)?
A. For each vertebra, we measured the diameter of the central part of the body--meaning its
narrowest point--as well as the distance of the vertical axis from the pedicle to the lateral side of the
body, the axis of rotation, the degree of rotation and the metric movement. If we take into account
the fact that we've made hundreds of measurements for each vertebra; if we take into account that
those hundreds of measurements were repeated on each vertebra of a spine, changing the inclination
of the axis of rotation by one degree for 60 degrees (if I remember correctly) or perhaps more; if we
take into account that this was repeated with different vertebrae from at least a dozen educational
columns; if we take into account that we had to report the degrees in millimeters, I think we’ve
collected about 30,000 to 40,000 pieces of data.
The collected data were classified according to the corresponding vertebrae of the other columns, to
the diameter of the vertebral body, to the distance of the pedicles and to the spatial arrangement of
the axis of rotation. This amounted to 21 books (as many as the vertebrae we've studied: four
cervical, excluding the first three due to insurmountable difficulties; 12 thoracic; and five lumbar),
each of which contained thousands of data. However, the hardest thing was yet to come. As a matter
of fact, all those numbers were of little use if not just to demonstrate the degree of rotation of the
vertebrae. We had to decide how to summarize and present them in such a way that they could be
synthesized. The description was very difficult because of the thousands of pieces of data we had
collected. So, in order to ensure that the different diameters corresponded to different vertebrae, we
made the average of all the values we had collected. Then, step by step, by doing mathematical
averages, the large amount of data was reduced in order to be presented on a slide ruler.
Q: Why are there a ruler version and a table version?
A: There are four reasons. First, in the study of the lumbar spine, among many L5 vertebrae that
were analyzed according to the measurement value imposed by methodology, we found a single
educational vertebra with a 64mm diameter and one with a 70mm diameter. All the other L5
vertebrae didn't reach these values. The diameters of the two columns of the L5 vertebral body
(anatomical evidence), with regard to the measurement value given by the methodology, were
57mm and 60mm. These are values that I remember very well, because they were reasons for great
reflection in order to decide whether we should continue our research up to 70mm in diameter (the
detection value). Secondly, contrary to the values we had obtained up to about 60mm, which
resulted from the study of more vertebrae of the same type, from 60 to 70mm, the study was done
by manipulating vertebrae with known diameters. That is, in order to obtain data up to 70mm in
diameter (still referring to the measurement value) the diameter of the vertebra of 60mm together
with all the other parameters (particularly those of the peduncles) was artificially increased to
70mm by adding a layer of synthetic material. All this was because we couldn't find vertebrae that
had such diameters. Coming back to your question, I remember that during a conference where I
gave a lecture on vertebral rotation in scoliosis and was illustrating the use of the ruler (which
indicated the vertebral diameter up to 60mm), some participants pointed out that perhaps that
diameter wasn’t sufficient for a lumbar vertebra (although the measurement value of the vertebral
diameter didn’t exceed 60mm). While arguing that such large vertebrae couldn’t be human, in order
to prevent other such observations and having the data available (even if they were artificially
made, as shown), we designed the tables by increasing the body diameter. Thirdly, I wanted to
suggest a "pocket" ruler but, by increasing the length of the ruler due to more data, it wouldn't have
been very handy. Fourthly, reading tables proved to be faster and more practical while offering the
possibility of observing the performance of various values. Moreover, the tables could be published
in any text and were therefore usable by everyone, as opposed to the ruler.
Q: How reliable is the Raimondi method?
A: Probably the methodology would be free of errors and a hundred percent reliable if, for
measuring and assessing data, one would refer to the actual data collected during research, because
it’s hard mathematical data. One can’t use all that data, however, or the method would lose its
efficiency and speed of use. Moreover, I don't consider that absolute accuracy is vital because, from
doing measurements on an x-ray to detecting the degree of rotation, you can encounter two types of
errors. I call the first error a "genetic" one and the second an operational one, being equal for all
methods. The genetic error of the Raimondi method is due to the fact that tens of thousands of
pieces of data were synthesized in exactly 3,000, as reported on the tables, which originate from the
averages of various discovered values. A vertebra with a 30mm diameter and a pedicle distance of
7mm provides a 20° rotation. However, the 30mm diameter reported on rulers (or tables) contains
an average of the diameters of several vertebrae subjected to measurement. Let me give you an
example. The mathematical value of 30mm (on the ruler or tables) includes mathematical values of
vertebrae ranging from 29.6 to 30.5mm in diameter. This generates an error, because the tenths of a
millimeter (although unnecessary) aren’t included on the tables (or rulers). Still, the measurement of
a vertebra 29.5mm in diameter (depending on the operator) can be considered a vertebra with a
29mm diameter or a 30mm diameter. This generates an additional error that affects the degree of
rotation. Then there are errors that might occur in all the measurement methodologies originating
from variable amounts, which I define as being ”operational.” There are errors that arise due to the
impossibility of establishing with certainty the radiographic shadow; from the difficulty (but also
from the operator's error) of measuring the distance between the vertebral edges and the pedicles;
from the difficulty of identifying the major axis of the pedicle; from interpreting, from higher or
lower approximations; from tracing evidences, etc. It is clear that none of these variables can
determine precise measurements. During various experiments I’ve conducted together with other
operators in this field, I've rarely observed unambiguous values. I've always noticed differences of
one, two, five degrees (sometimes even more) between one operator and another. However, I
believe the difference of two or three degrees is not relevant in measuring a rotation. Having said
that, I like to remember a sentence that Weiss once said:(26) “The Raimondi ruler is easier to use and
is slightly more reliable.” I'd like to add that, in the Italian guidelines for treating scoliosis and other
spinal deformities,(27) it is desirable to use the Perdriolle torque (another method of measurement) or
the Raimondi method as a means to measure vertebral rotation. I think the fact that, internationally,
the Raimondi method is confirmed, discussed, used and criticized(26-32) while also being used as a
reference to validate other methods is a good sign of ”reliability.” Usually, the criticism is positive.
I'd like to close with a statement by Rigo(29) that fits perfectly: "The Raimondi method is also a
useful and practical tool with which to measure the vertebral rotation directly on the computer
screen in a clinical setting . . . but it should be used with caution when making decisions."
Q: What do you think of the various three-dimensional analysis studies and the Formetric?
A: I don't really have a completely positive opinion about 3-D analysis in general. Many studies are
done superficially. Some researchers have tackled 3-D analysis by reconstructing the column from
two x-rays--latero-lateral and posterior-anterior--following the exact identification of anatomical
markers according to various protocols: An x-ray of the election plane of the spine is missing, let's
say, a projection of approximately 30 to 45 degrees. Then, others suggest replacing the 3-D analysis
of x-rays, which is not possible because vertebral deformations, rotations and values of lateral
flexion can’t be assessed with adequate precision. More than being a 3-D analysis of the column,
it’s a formal reconstruction of the trunk from which we get the hypothetical “spinometry”.
Confronting this issue would take a long time. Here’s an example for everyone: A deposit of fat or
muscle hypertrophy on one side of the column, a salience due to any reason, having nothing to do
with the scoliotic curve, can be interpreted by the instrument as a salience or a hump. Currently, for
the various assessment investigations of the spinal column, reasonably accurate techniques are used:
from simple x-rays to more sophisticated radiological techniques (the 3-D reconstruction of the
spine is achieved through many methods, based on x-rays, CT, digital radiology, the most
complicated stereo-radiography, etc.). However, the difficulty for clinical applications is inherent in
the exact spatial reconstruction, which must indicate the exact placement of the vertebrae. Certain
rare studies have been made to verify the precise orientation of the vertebrae, but it isn’t easy to
determine, for each vertebra, the orientation relative to the beginning of the rotation, and ultimately,
when calculating the various transformations it can undergo from the initial position (physiological
spatial position) to the final (scoliotic spatial position). It isn’t easy. We, the Mechanical
Engineering Department of Aquila, have also tried to do something in that regard, but the moment
everything seemed perfect some new variable would be added for consideration and we’d have a
new problem to solve. One researcher is even building a three-dimensional model with ligaments
and muscle activities that highlights the tissue deformation depending on the movements of the
spinal column. The research is currently in progress. Otherwise, to assess the current situation of the
posture of a torso, the techniques generally used involve the metric measurement of the photograph
and observation, but this results in various questions regarding the actual accuracy. In fact, the
observation and measurement, even when subjected to a protocol, are personal evaluations and can
therefore differ from operator to operator. Additionally, different authors use different
methodologies that, even if they're seldom repeated, provide the same result. Focusing on the
second part of the question, I believe the introduction of the Formetric technique in the analysis of
the spine (as it is understood and based on its promises), in contrast to other techniques, is not
meant to replace radiography but that, in addition to the many fundamental parameters it is able to
acquire, it has definitely rendered obsolete all the tools used to date. It allows us to code the
assessment; it renders the same evaluation repeatable without the use of various instruments; it
facilitates and integrates the postural measurements (which we know are abundant and subject to
multiple factors, some of which are detectable only by the expert physician); it doesn’t produce side
effects; it allows the "photographic" view of the exam; it allows the complete reading of the
acquired parameters; it provides a good approximation of the vertebral coordinates; there is no need
to position a marker on the subject; the instrument can be supplemented with other methods of
evaluation; it can be extremely useful in the screening; it can assist in evaluating the effects of
prosthetics; and it facilitates the easier compilation of statistics. The Formetric scanner (but not
spinography, as some may write) in this case is indispensable to the physician as a supplement to
his/her assessment as a specialist, both through the postural and purely clinical perspectives. It can
be a supplement to (along with other instrumental analyses) the physiotherapist in evaluating the
rehabilitative path of subjects with spinal alterations of different levels, before and during the
rehabilitation periods; it can be helpful to the doctor of sports medicine in postural and/or
morphological assessment; and it can be helpful to the expert in the human body. With appropriate
technological supplements, the device is capable of detecting several parameters useful for a
mechanical/anthropometric assessment of the body. In the various levels of alterations of the spinal
column, this technology is highly effective and efficient, and it’s free of any contraindication from
other research methods. Therefore, considering the premises and promise that such an instrument
offers, I can state (based on my modest skills) that I have an excellent opinion of the spinal
measurement detections; a great opinion regarding the detection of various levels of curves and
their correlation with vertebral rotation; a good opinion regarding the truthfulness of the data; and a
satisfactory opinion of the cost of the equipment. At a lesser price, this equipment would be "the
best" for any expert on the subject.
Q- What are some of the criticisms that other authors have made in regard to the "Raimondi"
method?
A- I met Perdriolle in a conference many years ago, and he congratulated me on the ingenious
method. This is the best criticism I could quote, because Perdriolle is a master. Generally, the
criticism is positive, but it doesn't take away from the fact that most operators who criticize the
method use it improperly or don't know how to use it (which of course generates many errors). I’ve
had the opportunity to observe many documents on the Web, as well as many forums and debates
on the methodology, but often I was able to certify that the operations weren’t relevant. I’ll give you
an example: The measurement of the distance from a spinal border and the contralateral in
radiography has to be taken halfway from the quoted height of the vertebra. Thus the fact that at
times it isn’t possible to do so is criticized. It's true, just as it’s true that the radiographic shadow of
the trunk in large rotation is sometimes confused. So, there! I don’t accept this criticism, because in
all my work where I write about the vertebral rotation, even if I advise one to detect the distance of
the lateral borders halfway from the height of the vertebra, I add that a measurement alteration of
about a millimeter (from the indicated quote) above or below does not cause great errors because,
proportionally, if it increases the vertebral diameter it also increases the distance between the border
and the major axis of the trunk. This compensates for the degree of rotation. Nevertheless, as with
any method of measurement that is subject to various errors--as in the measurement of Cobb
degrees--there exists a margin of measurement error (usually (± 5°)), and even in the Raimondi
method there is a margin of error. It cannot be otherwise, considering the fact we're evaluating
something that already contains errors from the beginning (radiography). Moreover, if a vertebra is
so deformed that markers cannot be identified, then the diameter of the vertebra below and above
the one being measured can be detected, the average can be calculated and the resulting value can
be assigned to the vertebra with the diameter that cannot otherwise be measured. For example, if the
diameter of an L2 cannot be measured, one should proceed as follows: The diameter of the L1 is
measured (37 mm), followed by the diameter of the L3 (41 mm.). The average of the two values is
39 mm. Therefore, the diameter of 39 mm can be assigned to the L2 vertebra. The error is minimal
in this case, but at least we have measured the vertebra. In the possible re-measurement, if the same
operational difficulty remains, one can proceed in the same manner. However, we often observe
that generally half of the vertebra being measured is perfectly legible while the other half
demonstrates overlapping signs that make measurement impossible. Therefore, in such a case, since
half the vertebra is legible, one can calculate the diameter knowing the value of its half. In other
words, there are several measurement strategies. Rigo(29) asserts that we must use the method with
caution. It's true. I would add that we should also use a bit of good commonsense, because all that is
"of the human body" is difficult to measure.
Q: How would you define the Formetric scanner after having studied it to verify the thesis you
presented, and having participated in the acquisition of measurements?
A: In much of my work on vertebral rotation, I always confirm that all vertebral measurement
methods, including mine, are inaccurate. I will add that only with future virtual-reality techniques
can it be possible to determine the vertebral rotation with minimal error. In the early days of
technology--in the days of the Integrated Shape Imaging System--I had various doubts. Eventually,
with rasterstereographic techniques, my doubts decreased. Currently, after my evaluation and
having expressed my humble opinion earlier, I think the Formetric scanner can be considered as
“homo sapiens" in the evolution of morphological detection, starting from the primordial "moiré
effect,” and certainly, in its future inevitable evolution, it could be considered as the “homo sapiens
sapiens" of detection in the human anthropometric measurement technique.
Bibliography
1) Conversation with Paolo Raimondi on vertebral rotation, recorded in October 2010. Faculty of
Sports Sciences of the Univeristy of Aquila.
2) André B, Dansereau J, Labelle H. Optimized vertical stereo base radiographic setup for the
clinical three-dimensional reconstruction of the human spine. J Biomech. 1994;27:1023-1035
3) Aubin C, Dansereau J, Parent F, Labelle H, Guise J. Morphometric evaluations of personalised
three-dimensional reconstructions and geometric models of the human spine. Med Biol Eng
Comput. 1997;35:611-618.
4) Benameur S, Mignotte M, Labelle H, Guise J. A hierarchical statistical modeling approach for
the unsupervised three-dimensional biplanar reconstruction of the scoliotic spine. IEEE Trans
Biomed Eng. 2005;52:2041-2057.
5) Chen YT, Wang MS. Three-dimensional reconstruction and fusion for multi-modality spinal
images. Comput Med Imaging Graph. 2004;28:21-31.
6) Cholewicki J, Crisco J, Oxland T, Yamamoto I, Panjabi M. Effects of posture and structure on
three-dimensional coupled rotations in the lumbar spine: a biomechanical analysis. Spine.
1996;21:2421-2428.
7) Dumas R, Steib JP, Mitton D, Lavaste F, Skalli W. Three-dimensional quantitative segmental
analysis of scoliosis corrected by the in situ contouring technique. Spine. 2003;28:1158-1162.
8) Gille O, Champain N, Benchikh-El-Fegoun A, Vital JM, Skalli W. Reliability of threedimensional reconstruction of the spine of mild scoliotic patients. Spine. 2007;32:568-573.
9) Huynh T, Dansereau J, Maurais G. Development of a vertebral endplate three-dimensional
reconstruction technique. IEEE Trans Med Imaging. 1997;16:689-696.
10) Labelle H, Dansereau J, Bellefleur C, Jéquier J. Variability of geometric measurements from
three-dimensional reconstructions of scoliotic spines and rib cages. Eur Spine J. 1995;4:88-94.
11) Lee SM, Suk SI, Chung ER. Direct vertebral rotation: a new technique of three-dimensional
deformity correction with segmental pedicle screw fixation in adolescent idiopathic scoliosis. Spine.
2004;29:343-349.
12) Masharawi Y, Rothschild B, Dar G, Peleg S, Robinson D, Been EIH. Facet orientation in the
thoracolumbar spine: three-dimensional anatomic and biomechanical analysis. Spine.
2004;29:1755-1763.
13) Mitton D, Landry C, Véron S, Skalli W, Lavaste F, Guise J. Three-dimensional reconstruction
method from biplanar radiography using non-stereocorresponding points and elastic deformable
meshes. Med Biol Eng Comput. 2000;38:133-139.
14) Mitulescu A, Semaan I, Guise J, Leborgne P, Adamsbaum C, Skalli W. Validation of the nonstereo corresponding points stereoradiographic three-dimensional reconstruction technique. Med
Biol Eng Comput. 2001;39:152-158.
15) Pearcy M, Tibrewal S. Axial rotation and lateral bending in the normal lumbar spine measured
by three-dimensional radiography. Spine. 1984;9:582-587.
16) Pomero V, Mitton D, Laporte S, Guise J, Skalli W. Fast accurate stereoradiographic threedimensional reconstruction of the spine using a combined geometric and statistic model. Clin
Biomech (Bristol, Avon) 2004;19:240-247.
17) Skalli W, Lavaste F, Descrimes JL. Quantification of three-dimensional vertebral rotations in
scoliosis: what are the true values? Spine. 1995;20:546-553.
18) Stokes I. Three-dimensional terminology of spinal deformity: a report presented to the Scoliosis
Research Society by the Scoliosis Research Society Working Group on three-dimensional
terminology of spinal deformity. Spine. 1994;19:236-248.
19) Tan S, Teo E, Chua H. Quantitative three-dimensional anatomy of cervical, thoracic and lumbar
vertebrae of Chinese Singaporeans. Eur Spine J. 2004;13:137-146.
20) Tan S, Teo E, Chua H. Quantitative three-dimensional anatomy of cervical, thoracic and lumbar
vertebrae of Chinese Singaporeans. Eur Spine J. 2004;13:137-146.
21) Vrtovec T, Likar B, Pernuš F. Automated curved planar reformation of three-dimensional spine
images. Phys Med Biol. 2005;50:4527-4540.
22) Vrtovec T, Pernuš F, Likar B (2008) A symmetry-based method for the determination of
vertebral rotation in three dimensions. In: Metaxas D, Axel L, Davies B (eds) Lecture Notes in
Computer Science (LNCS): proceedings of the 11th medical image computing and computerassisted intervention-MICCAI 2008, Springer, New York, NY, USA, Volume 5241, pp.942-950.
23) Yao J, O’Connor S, Summers R (2006) Automated spinal column extraction and partitioning.
In: proceedings of the 3rd IEEE international symposium on biomedical imaging: from nano to
macro-ISBI 2006. IEEE, Arlington, VA, USA, pp.390-393.
24) Fergusson AB, Roentgen Diagnosis of the extremities and spine. Paul B. Hoeber, Inc., New
York, 1945, pp.261,275.
25) Nash CL, Moe JH. A study of vertebral rotation J. of bone and joint surgery 1969;51:223-229.
26) Weiss HR. Measurement of vertebral rotation: Perdriolle versus Raimondi Eur Spine J
1995;4(1):34-8.
27) Negrini et al. Italian guidelines on rehabilitation treatment of adolescents with scoliosis or other
spinal deformities. Eur Medicophys 2005;41:183-201
28) D’Amico M, Merolli A, Santabrogio GC. Three-dimensional analysis of spinal deformities. IOS
PRESS. 1995, pp.243-45.
29) Rigo M. Villagrassa M. Technical error of vertebral rotation measurement directly on the
computer screen, according to Raimondi Method. Scoliosis 2010;5(1):0-14.
30) Alan P. Pinheiro, Michelle C. Tanure and Anamaria S. Oliveira Validity and reliability of a
computer method to estimate vertebral axial rotation from digital radiographs. Eur Spine J
2009;19(3):415-20.
31) Defino HLA; Araújo, PHM. Comparative study of the measurements of the vertebral rotation
using Nash & Moe and Raimondi methods. Acta ortop. bras. 2003;vol.12 (3):167-173.
32) Pinheiro AP, TanureMC, Oliveira AS. Validity and reliability of a computer method to
estimate vertebral axial rotation from digital radiographs. Eur Spine J 2010;19(3):415-20.