HEALTH
EFFECTS: X-Ray Diagnosis of Skeletal Fluorosis
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Summation
- X-ray Diagnosis of Skeletal
fluorosis
 In
1937, Kaj Roholm published his seminal study Fluorine Intoxication.
Based on observations of skeletal fluorosis in fluoride-exposed
workers, Roholm described three phases of bone
changes detectable via x-ray. Roholm's description of the
x-ray picture of skeletal fluorosis has been widely
used as a diagnostic tool in detecting the disease. It is
not, however, without its limitations.
In 1958, the German scientist Fritz expanded
on Roholm's description of the x-ray picture, by defining two
additional phases ("subtle signs" & "stage
O-I") of bone changes that occur prior to Roholm's 3 phases.
Other researchers have called attention to a more diverse
range of radiological findings, beyond the predominantly osteosclerotic
form of the disease which Roholm described.
In addition, others have reported that the symptoms of skeletal
fluorosis can occur before the
development of bone changes detectable by x-ray. This latter research
has emphasized the problems of relying on x-ray analysis to diagnose
fluorosis, as x-rays are bound to overlook individuals suffering
from the early, "pre-skeletal"
stage of fluorosis.
Diagnosing Skeletal Fluorosis
- Roholm's 3 Phases of Bone Changes
Detectable by X-Ray: (back to top)
"From the X-ray picture it is possible to differentiate
between three phases of the same osteosclerotic process, each
overlapping the next without any sharp boundary.
1st Phase.
"The changes are observed in pelvis and columna, but are
doubtful or absent elsewhere. The density of bone is very little
increased. The trabeculae are rough, blurred and give deep shadows;
this is often distinct in corpora of the lower lumbar vertebrae.
The bone has both a more prominent and a more blurred structure
at the same time, which is very characteristic when the operator
is familiar with the phenomenon, but otherwise is easily overlooked.
The bone contour is sharp. In some few cases there is incipient
osteophyte formation on the edge of corpora of the lumbar vertebrae.
The boundary against the normal bone structure is not sharp, and
in an isolated case it will be difficult to decide whether the
change is a normal variation or a pathological finding. In serial
examinations, however, the difference is distinct.
2nd Phase.
"The bone structure is blurred, the trabeculae merging together.
Over often rather large areas the bone gives a diffuse, structureless
shadow. At first glance the negative seems to have been underexposed,
but it is difficult or impossible to distinguish details even
when the time of exposure or the tension is increased. The bone
contours are uneven and somewhat blurred. The changes are most
distinct in pelvis and columna, but also in the ribs and in the
bones of the extremities, even if there they are less pronounced
and often resemble the changes described as 1st phase. In the
extremity bones the medullary cavity is usually moderately narrowed.
In columna there are incipient or moderate ligament calcifications,
especially caudally; they appear in the form of pointed, beaked
osteophytes with an inclination to form bridges between vertebral
bodies or as a diffuse blur lying posteriorly to corpora. In some
cases (particularly among the younger individuals) the ligament
calcifications are absent, though the bone structure is so changed
that the case must be placed to the 2nd phase.
3rd Phase.
"On the negative the bone presents itself as a more or less
diffuse marble-white shadow, in which the details cannot be distinguished.
Changes are observable in all bones but are still greatest centrally,
being most conspicuous in bones with cancellous structure, pelvis,
columna, ribs and sternum. In the bones of the extremities there
are changes in the structure that recall the 2nd phase, or fairly
often only the 1st phsase. Among the worst affected individuals
changes are to be seen in the cranium, usually rather moderate
in intensity. Theca is denser and gives a deeper shadow than normally,
sutures and vessel grooves are indistinct, and the same applies
to impressiones digitatae. The air-sinuses in the cranial bones
are diminished in size. The region around sella turcica gives
a deep shadow but is normal as to contour. No distinct thickening
of the processus clinoidei was observed.
The bone contours almost everywhere are wooly and blurred. Very
often the bones or certain parts of them have a rough and slightly
enlarged appearance, but otherwise the shape is not altered. On
the extremity bones are irregular periosteal thicknesses, some
flats, others more rough. The interosseous membrane in antibrachium
and crus are calcified to a greatewr or smaller extent. The normal
cristae corresponding to the muscle attachments are increased
in size and resemble exostoses. On costae, especially vertebrally,
there is calcification of the insertions of the intercostal muscles,
which appear like "rime frost needles" or irregular
shadows to both sides. There are considerable ligament calcifications,
varying up to very severe, in columna, particularly in pars lumbalis
and thoracalis. In columna cervicalis these changes are less pronounced,
but distinct. The ligament calcifications appear partly in the
form of bridge-like connections with fairly sharp borders between
corpora, partly as a diffuse opacity and density round about the
intervertebral and costovertebral articulations. Processus transversi
and spinosi are rough and thickened; between the latter are considerable
ligament calcifications with irregular borders. In the pelvis,
ligamentum sacrotuberosum is sometimes calcified. The intensity
of the calcification and the diffuse density of the bone usually
are in conformity with each other; in some elderly workers, however,
there is a density of the osseous tissue which does not attain
to the extreme degree, side by side with very pronounced ligament
calcification.
In the extremity bones, both short and long, the medullary cavity
is diminished in width and the boundary against compacta is less
sharp than normally. The width of compacta is correspondingly
increased. In tibia and femur the width of the medullary cavity
sometimes decreases to half the normal, in metacarpals and phalanges
there is sometimes a partial occlusion of the cavity.
The interarticular spaces are of normal width everywhere and
the contours are sharp. Limited calcifications of the capsule
in hip and knee joints are seen. The intervertebral disks are
not visibly changed and the calcification of the costal cartilage
does not exceed the normal.
If the result of the Rontgen examination is to be summarized,
the first thing to emphasize is the fact that the affection is
a system-disease, for it attacks all bones, though it has a predilection
for certain places. The pathological process may be characterized
as a diffuse osteosclerosis, in which the pathological formation
of bone starts both in periosteum and in endosteum. Compacta densifies
and thickens; thet spongiosa trabecula thicken and fuse together.
The medullary cavity decreases in diameter. There is a considerable
new-formation of bone from periosteum, and ligaments that normally
do not calcify or only in advanced age undergo a considerable
degree of calcification. All signs of bone destruction are absent
from the picture."
SOURCE: Roholm K. (1937). Fluoride intoxication: a clinical-hygienic
study with a review of the literature and some experimental investigations.
London: H.K. Lewis Ltd. pp. 141-143
Diagnosing Skeletal Fluorosis:
Two Additional Phases
of Bone Changes described by Fritz (1958): (back
to top)
"In addition to the well-known radiological stage classification,
stage I to III according to Roholm, two prestages according to
Fritz have proved to be important in our investigations: the so-called
(subtle signs) and the stage O-I. Concerning the subtle signs...
a condensation of the bone-structure and an enlargement of the
bone trabeculae in the lumbar spine are evident. In addition,
there are accompanying shadows along the tibia, fibula, radius,
and ulna. At the stage O-I the structure of the thoracic spine
has already increased in density, whereas in the lumbar region
the normal structure of the bone begins to disappear. The periosteal
apposition of new bone at the bones of the forearm and lower legs
are more distinct. For better proof of the periosteal appositions
on these bones, we used slightly underexposed similar to the kind
of radiography employed for soft parts."
SOURCE: Franke J, et al. (1975). Industrial fluorosis. Fluoride
8: 61-83.
Diagnosing Skeletal Fluorosis:
US Public Health Service
Chart (back to
top)
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