ABSTRACT
X-ray analysis has historically been the assessment of choice for analyzing
the occipito-atlanto-axial subluxation complex. There are also several quick
non-radiographic methods that are used clinically to test for atlas subluxation,
such as leg checks, palpation and thermography. If non-radiographic methods can
be found that accurately predict atlas misalignment, they might provide a safer
alternative for routine screening of patients. Although non-radiographic methods
are reputed to be accurate measures of upper cervical subluxation, a thorough
investigation into the agreement between methods has yet to be done.
This retrospective study was carried out to assess the level of agreement between the Grostic Procedure of upper cervical x-ray analysis and six other methods of assessing upper cervical subluxation. Patient information in this study was derived from the files of a doctor of chiropractic in private practice. Clinical findings were recorded in a specially designed computerized database which was then queried to construct agreement tables for the various assessments. The Kappa statistic was calculated and used as an indication of agreement.
The data presented in this retrospective study shows that there is a poor
correlation between upper cervical x-ray analysis and the other analyses
presented. The results suggest that while non-radiographic methods might be
useful as pre- and post-adjustment screening checks, they should not be relied
on to provide misalignment listings for adjustment.
Key words: occipito-atlanto-axial subluxation complex,
Grostic Procedure, adjustment, computerized database.
INTRODUCTION
Although the existence and description of the vertebral subluxation complex
has been debated in the chiropractic and medical literature, it is still
considered by many to be the fundamental tenet of the chiropractic profession.
(1-11) Due to the unique anatomy of the upper cervical spine, (12,13) the
analysis of subluxations in this area pose a challenge for many doctors of
chiropractic and a variety of methods have been devised. Medical physicians also
have used various methods to measure misalignments of the upper cervical spine,
and after the application of traction, manipulation or surgery, they have
verified the subluxation's reduction with the use of post x-rays and CT scans.
(12, 14-26) Since many chiropractors base their treatment on the analysis of the
vertebral subluxation complex, the accuracy of this analysis is vital for the
quality and safety of chiropractic patient care.
There exist within the chiropractic profession several different methods for
determining the misalignment components of the upper cervical subluxation. From
the 1920's to the present, x-rays have been used to determine adjustment
listings in virtually all upper cervical specific techniques. One particular
x-ray analysis method, pioneered by Dr. John F. Grostic (27-29), has formed the
basis for a family of x-ray analysis procedures including Orthospinology, (30)
NUCCA, (31) Orthogonality,(32) Life Cervical, (33) and early versions of the
Pettibon method(34). This system has been used and tested clinically in various
settings since the 1940's, and has been shown to have high inter- and
intra-examiner reliability in recent reliability studies. (35-38)
The Grostic Procedure employs x-ray analysis to quantify the lateral and
rotational misalignments between atlas and axis as well as atlas and occiput.
The analytical procedure examines the spatial orientation of the atlas, the
geometry of the articular surfaces, and the misalignment configuration to arrive
at an effective correction vector. In addition to the x-ray analysis, the
Grostic Procedure uses specific methods to ensure the precision of the x-ray
analysis. There are also post adjustment re-evaluation procedures which allow
the doctor to assess the effectiveness of the adjustment and, of equal
importance, to fine-tune the adjustment to the individual patient. (28)
In general, the Grostic nasium x-ray analysis is used to determine an upper
angle, the angle between the vertical center of the skull and the plane of the
atlas, and a lower angle formed between the atlas plane and the center of the
lower cervical spine. Atlas "laterality" is found by looking for an acute upper
angle. The Grostic analysis of the vertex film is used to determine atlas
rotation with respect to the skull.
Subluxations analyzed following the Grostic Procedure fall into two general patterns: opposite angle and kink subluxations. In the kink pattern, represented in figure 1, acute angles are seen on the same side of the spine in both the upper and lower angles. In the opposite angles pattern, the acute upper and lower angles are on opposite sides of the spine, as shown in Figure 2.
The Grostic analysis also lists the position of the C2 spinous process with
respect to the atlas. A right or left inferior axis spinous indicates that the
axis spinous process has misaligned to the same side of atlas laterality. Figure
1 also shows an inferior C2 spinous. A right or left superior axis spinous
indicates that the axis spinous process has misaligned to the opposite side of
atlas laterality, as shown in figure 2. (29)
Many chiropractic techniques, besides the Grostic based techniques mentioned
above, also have specific methods for assessing and adjusting the upper cervical
spine. Those that do not use x-ray analysis use other clinical indicators to
decide whether the atlas is misaligned, and in which direction. I was taught in
chiropractic college that any of these clinical indicators should produce the
same results. This conclusion was based on the clinical experience of my
instructors and their general understanding of the techniques. As a matter of
curiosity I decided to test several non-radiographic methods of determining
atlas subluxation using data already collected on the patients in my private
practice of chiropractic.
The following six hypotheses were tested:
1. Activator analysis can be used to determine atlas laterality, rotation and axis rotation.
2. Posture analysis can be used to determine atlas laterality, rotation and axis rotation.
3. Restricted cervical range of motion can be used to determine atlas laterality, rotation and axis rotation.
4. Static palpation can be used to determine atlas and axis rotation.
5. The side of the colder infrared temperature at the C1 fossa is the side of atlas laterality.
6. Kink subluxations will usually cause a functional short leg on the side of
atlas laterality. Opposite angle subluxations will usually cause a functional
short leg on the opposite side of atlas laterality.
Although non-radiographic methods are reputed to be accurate measures of
upper cervical subluxation, a thorough investigation into the agreement between
methods has yet to be done. This study will compare upper cervical listings
found using the Grostic Procedure x-ray analysis to those found with various
other non-radiographic methods. If non-radiographic methods can be found that
accurately predict atlas misalignment, they might provide a safer alternative
for routine screening of patients.
METHODS
In examining patients in my practice, I routinely carry out and record checks
from several different chiropractic methods. The results of each examination are
stored in a custom database that I use for patient tracking and research.
X-ray Analysis
Lateral, nasium and vertex radiographs were taken routinely as part of the
patient's care. The Grostic x-ray analysis procedure was used to analyze the
radiographs for listing factors, including atlas laterality and rotation, lower
angle and C2 spinous displacement. The x-ray listings were used to derive
adjustment vectors for upper cervical care.
Supine Leg Check
The supine leg check was performed on each patient following the Grostic
Procedure. The patient was instructed to stand at the foot of the Grostic
adjusting table, sit down on the end of the table and then slide back and lay
down in a supine position. Each foot, with the shoe on, was grasped in the
examiners hands and positioned with slight headward pressure so that the soles
of the shoes were in the same plane. The relative leg length difference was then
viewed at the shoe/sole interface and estimated to the nearest 1/16 inch.
Activator Leg Checks
The following analysis was derived from the activator advanced manual (39)
and backed up by the verification of two activator instructors. The analysis
involves carefully placing the patient prone on a hi-lo table, with their lower
legs slightly flexed. The leg check is performed with the legs in two separate
positions, one fully extended and one flexed to 90 degrees at the knee. The
Position #1 leg check is done by cupping the palms of the hands over the lateral
malleoli and bringing the legs together until the heels touch and are
perpendicular to the legs. The thumbs are then placed under the heel of each
shoe, the index fingers posterior to the lateral malleoli, and the middle finger
anterior to the lateral malleoli. The thumbs are used to take out any supination
or inversion of the feet and a gentle constant headward pressure parallel to the
tibias is applied. The side of the functional short leg (i.e. pelvic
deficiency), if any, is observed by comparing the shoe-sole interface as a
reference.
The relative leg length is also checked with the legs flexed 90 degrees at
the knees (Position #2). In this position, the legs are held up in the flexed
position and the doctor sites along the soles of the shoes to decide which leg
is longer.
To assess the upper cervical spine, the Activator analysis provides a special
"stress test" procedure, which involves having the patient flex their neck while
the examiner checks the leg length difference. If a pelvic deficiency (PD) is
observed in position #1 and crosses over in position #2, then it is considered
positive for C1 laterality on the side of PD. If the leg does not cross over,
then it is considered C2 spinous rotation to the side of PD(40). If C1
laterality is found, then C1 rotation is determined by having the patient turn
their head to the side of PD. If the leg crosses over in position #2, C1 is
considered posterior on that side. If the leg stays short in position #2, C1 is
considered anterior on that side. Another method for determining atlas rotation
involves checking for balancing of the pelvic deficiency as the patient turns
their head to one side or the other. For example, if the right PD leg balances
when the head is turned to the right, then C1 is anterior on
the right, if the right PD leg balances when the head turns to the left, then C1
is posterior on the right. While I am not certified in the
Activator Methods, many of the leg checks performed using the method were
supervised by an associate in my office who is certified.
It should also be noted that activator instructors recommend the use of a
"challenge" to verify the correct adjustment listing. A challenge is performed
by placing pressure on a vertebra in the direction that it is thought would
cause a correction. It is hypothesized that if the challenge is correct, it will
cause a temporary leveling of the leg length inequality. However, it is the
opinion of the researchers at Activator Methods that the standard method
described in the previous paragraph provides a more accurate assessment of atlas
subluxation than the challenge method.
Posture Analysis
Posture analysis has been used historically to monitor patients' progress to
chiropractic care, but it is also used by many chiropractors to determine how to
adjust the upper cervical spine. (41-43) The medical literature also contains
discussions on the relationship between postural distortion and musculoskeletal
pain and overall health. (44-45)
In posture analysis it is theorized that a high atlas plane line causes the
head to tilt away from the side of laterality. It is also thought that the head
will rotate in the same direction as the rotational misalignment, so that, for
example, right head rotation would be a right posterior C1 or left anterior C1
and/or PL C2 spinous (right superior or left inferior spinous).
For this study, a special posture analysis board was used on all patients and
a Polaroid picture was usually taken to record any postural deviations. The
posture analysis board, utilizing several horizontal lines and one center of
gravity line, was accurately installed utilizing a plumb bob. Head tilt was also
measured on the nasium x-ray.
Range of Motion
A general measure of cervical motion can be provided by measuring cervical
range of motion (ROM). For this study, cervical range of motion was measured
with inclinometers and/or an arthrodial protractor. A restricted cervical ROM
was considered significant if there was a side-to-side asymmetry of five degrees
or more. Based on cervical ROM, the side of atlas laterality should be on the
side of restricted cervical lateral flexion. It is hypothesized that vertebrae
can be locked in the direction they are misaligned and a restriction would occur
in any attempt to move the vertebrae away from their fixated positions. For
example, a right restricted cervical rotation ROM would accompany a right
anterior C1 or left posterior C1 and/or a PR C2 (right inferior or left superior
C2 spinous).
Static Palpation
Static palpation of the spine has been used in the analysis of vertebral
subluxations since chiropractic's inception. Although it is generally considered
to be a valuable part of most chiropractors' analysis, many researchers have
criticized the reliability of palpation in determining vertebral misalignment.
(3,56) In this study, the examiner palpated for tenderness or swelling in the
suboccipital muscles.
In Diversified technique, it is thought that the side of tenderness (i.e.
muscle bundle) in the upper cervical spine represents a posterior atlas and/or
body rotation of C2 on that same side. A positive palpatory finding at the C1-C2
region was considered significant when one side was predominantly more tender or
swollen than the other side.
Thermography
Heat detecting instruments have been used since the 1930's to monitor
patients' progress to upper cervical care (3,58), and like the other analyses
discussed in this paper, it has been found to be very valuable to many
chiropractors. It is thought by some doctors of chiropractic, and one of my
college instructors, that the side of atlas laterality will be found, in the
great majority of cases, to have a colder temperature when using an infrared
heat measuring instrument to test the C1 fossa areas. For this study, a
non-contact single probe infrared thermogaphy unit was used to measure the
temperature of the left and right atlas fossa on each patient.
DATA ANALYSIS
The patient database has a query function to help identify correlations
between clinical findings. For this study, a series of queries was performed to
specifically test each of the hypotheses under investigation. In each case, the
x-ray analysis method would result in a Right or Left listing, or a rotation
listing such as right anterior, right posterior, left anterior or left
posterior. Similarly, the non-radiographic methods would provide a side of
laterality or a rotation direction. During data analysis, the rotation listing
was translated into either a clockwise (CW) or counter-clockwise (CCW) rotation
for atlas or C2 by considering the transverse or spinous process movement
associated with each direction of rotation. For instance, C1 rotation in the
Grostic Procedure is listed with respect to the side of laterality, so a Right
Anterior C1 would be the same direction of rotation as a Left Posterior C1.
For each hypothesis, an agreement table was constructed, showing the number
of times the two methods agreed on a finding, and when they disagreed. The Kappa
statistic, which compares the percent agreement to the agreement expected by
chance was calculated from the agreement table using a spreadsheet program.
RESULTS
The calculated percent agreement and Kappa statistic for each hypothesis are
shown in Table 1.
| Factors Compared | N | Po% | Pe% | Kappa |
| Activator Atlas Laterality | 166 | 53 | 58 | -0.11 |
| Activator C2 Spinous | 108 | 49 | 51 | -0.04 |
| Activator Atlas Rotation | 160 | 72 | 54 | 0.40 |
| Head Tilt for Laterality (Kink) | 122 | 93 | 58 | 0.84 |
| Head Tilt for Laterality (Opp) | 227 | 54 | 53 | 0.01 |
| Head Tilt for Laterality (both) | 349 | 67 | 55 | 0.28 |
| Head Rotation for Atlas Rotation | 216 | 50 | 51 | -0.02 |
| Head Rotation for C2 Spinous | 135 | 54 | 51 | 0.06 |
| Lateral Flexion for Laterality (Kink) | 31 | 35 | 40 | -0.07 |
| Lateral Flexion for Laterality (Opp) | 77 | 41 | 40 | 0.03 |
| Cervical Rotation for Atlas Rotation | 111 | 56 | 54 | 0.03 |
| Cervical Rotation for C2 Spinous | 83 | 66 | 53 | 0.28 |
| Scanning Palpation for C1 Rotation | 337 | 48 | 48 | 0.00 |
| Scanning Palpation for C2 Rotation | 231 | 44 | 49 | -0.09 |
| Low C1 Temp. for Laterality (Kink) | 51 | 53 | 51 | 0.03 |
| Low C1 Temp. For Laterality (Opp) | 188 | 56 | 53 | 0.05 |
| Short Leg for Laterality (Kink) | 170 | 42 | 51 | -0.17 |
| Short Leg for Laterality (Opp) | 468 | 54 | 53 | 0.00 |
In the table, N is the number of patients who had data for both of the factors being compared, Po% is the percent of agreement observed and Pe% is the percent of agreement expected by chance, given the distribution of data.
In general, Kappa can range from -1 to 1. A value of 1 represents perfect
agreement between two methods or examiners, while a -1 would exist if the two
methods contradicted each other perfectly. A Kappa value of 0 shows that the
percent agreement observed is equal to that you might get by just guessing at
random.(46) In this study Kappa ranged from -0.17 to 0.84. The best agreement,
Kappa = 0.84, was observed between Head tilt measurement and the side of atlas
laterality when a kink subluxation is present. The Activator check for atlas
rotation showed a moderate agreement, Kappa = 0.40, with the x-ray analysis.
DISCUSSION
The data from this study shows that head tilt and the side of atlas laterality are well correlated only when a kink misalignment is present. If a particular patient presents with a head tilt and you know from past radiographs that a kink misalignment is typical for that patient, then you can assume that some degree of misalignment is present and needs to be adjusted.
None of the other comparisons carried out in this study showed much agreement
at all. This is confusing in light of what is being taught in chiropractic
colleges. It points to the general uncertainty of using any non-radiographic
method to assess upper cervical misalignment patterns.
It is not unexpected that leg checks do not correlate well with the side of
atlas laterality. Several aspects of the upper cervical misalignment pattern may
play a part in producing spinal cord distortion and leg length inequality. For
example, the NUCCRA organization has examined correlations and developed
hypotheses in regards to the functional short leg and different subluxation
patterns. (47) Although some valuable information has been obtained from these
studies, no firm conclusions have been drawn. Dr. John D. Grostic performed a
study of the relationship between upper cervical misalignment factors and leg
check. Using an algorithm involving the upper angle, lower angle, axial and
condylar circle diameters, C2 spinous and atlas rotation, he was able to predict
the side of the functional short leg with 88% accuracy.(28)
In an attempt to simplify patient assessment, some doctors have hypothesized
that since most patients have an opposite angle subluxation, they will adjust
the patient's atlas on the side opposite of the supine short leg. This method
has been suggested for use with pediatric patients as well. An obvious question
needs to asked when using this logic. If x-rays are used to determine how to
provide care or to decide if care is contraindicated for adults, then why would
a doctor of chiropractic want to provide substandard care to a child whose
nervous system is still developing? An analysis of the data in this study shows
that leg length inequality is not an acceptable replacement for x-ray analysis.
Although it is up to the doctor of chiropractic to decide which analysis
he/she will rely on, it appears that they are not interchangeable with x-ray
analysis. A possible explanation for this is that the upper cervical spine is a
very complex area anatomically and neurologically. Because of the many
misalignment patterns that may occur in the occipito-atlanto-axial area, it
becomes very hard to make generalizations or to predict these multiple
misalignments without measuring them. Lord Kelvin, one of England's most
prominent physicists stated,
"When you can measure what you are talking about and express it in numbers,
you know something about it, but when you cannot measure it, when you cannot
express it in numbers, your knowledge is of a meager and unsatisfactory kind; it
may be the beginning of knowledge, but you have scarcely, in your thoughts,
advanced to the stage of a science."(48)
It appears that true knowledge and understanding of the vertebral subluxation
complex can only be achieved through quantitative analysis and characterization.
CONCLUSION
The data in this study reveals very poor agreement between x-ray and
non-x-ray methods of determining upper cervical misalignment. These two types of
patient assessments do not appear to be synonymous. While these results cast
serious doubt on the comparative use of radiographic and non-radiographic
methods, a firm conclusion cannot be drawn from this study because the data was
derived from only one practice and the doctor in this study was not blinded
during the patient assessments. On the other hand, the data was collected from a
large number of patients over a long period of time and, even though the
examiner was not blinded, data was collected before any plans had been made to
perform the statistical analysis on it.
From the author's standpoint, non-radiogaphic methods provide quick clinical
checks that are valuable in monitoring patients pre- and post-adjustment, but
should not be relied on for determining how to adjust the patient.
ACKNOWLEDGMENTS
The author would like to thank Jimmy Greer for his many months of hard work
in developing the computerized database. Thanks also go out to Gregory Hovanic,
D.C. for approving the activator analysis and proof reading this paper. Dr. Ed
Owens was instrumental in editing the manuscript and helping with data analysis.
Finally, love and thanks go out to the author's wife, Cynthia Eriksen, for
patience, support and love.
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