THE AMBULATORY TREATMENT OF 
POTT’S DISEASE. 
BY 
ROBERT W. LOVETT, M.D., 
OF BOSTON. 
FROM / 
THE MEDICAI/NE WS, 
Feb. 29, 1^(96. [Reprinted from The Medical News, Feb. 29, 1896.] 
THE AMBULATORY TREATMENT OF POTT'S 
DISEASE. 
ROBERT W. LOVETT, M.D., 
Pott’s disease is in itself only a tuberculous 
destruction of the anterior part of the bodies of 
the vertebrae. No deformity is necessarily atten- 
dant upon its occurrence, and the antero-pos- 
terior curvature of the spine, with which we 
always associate it, is really the result of the erect 
position. It is said that this deformity does not 
occur in quadrupeds. 
OF BOSTON. 
The present paper is an attempt to formulate 
certain problems which are met in the treatment 
of this affection by ambulatory means. When a 
surgeon, in starting to treat a case of Pott’s dis- 
ease by ambulatory methods, selects the force of 
gravity as his antagonist, rather than as his assist- 
ant, it is proper that he should appreciate the 
problem which he is undertaking and understand 
clearly the mechanical aspect of the case. Instead 
of keeping the patient with Pott’s disease in bed, 
if the surgeon allows him to go about, so that the 
heavy weight of the body comes upon the diseased 
segment of the vertebral column, the surgeon 
should know pretty definitely whether this is a 
matter that he can counteract by apparatus, or 
whether all mechanical support to the spine is not 
necessarily imperfect. The question is this; Can 
the spine be placed in as favorable a condition for recovery as during recumbency, and what is 
the mechanical value of the methods of ambu- 
latory treatment now in use? 
To consider, for example, a case of dorsal 
Pott’s disease in a boy weighing forty pounds, 
where the disease is located in the lower dorsal 
vertebrae, say the ninth, tenth, and eleventh. It is 
manifest that, inasmuch as the vertebral column 
bears all the body weight, and as the vertebral 
column is normally convex backward in the dorsal 
region, the weight of the body above the disease 
must needs be transmitted through the bodies of 
the dorsal vertebrae. This weight is the weight 
of the segment of the body above the diseased 
vertebrae. It includes the head, with the brain, 
the neck and its firm muscles, the shoulder girdle, 
from which hang the arms, which are of no little 
weight, and the upper part of the chest, with the 
contained organs. There is no support in front. 
These organs are hung simply from the backbone, 
from which the chest girdle runs out just as a 
crossbar does from a telegraph pole. It is 
not a bad estimate, I think, to place the weight 
of these organs which I have just mentioned as 
half the body weight—in this case twenty pounds. 
We will assume, then, that the problem in this 
especial case is to modify, if possible, the pressure 
which comes from this weight upon the diseased 
vertebrae, and that this pressure is the result of a 
twenty-pound superincumbent weight. 
The problem which efficient mechanical sup- 
port must solve is to remove or lessen the weight 
coming upon the diseased bodies of the vertebrae. 3 
The anteroposterior brace attempts to do this 
by acting as a lever which shall transfer the 
weight to the articular and transverse processes 
by pushing against the deformity as a fulcrum. 
In other words, it should modify intervertebral 
Fig. i. 
pressure. It is upon this theory that the brace 
was constructed and should be used. 
The model which is presented is a very imper- 
fect affair, but one which makes very clear some 
of the intrinsic difficulties met with in the treat- 4 
merit of Pott’s disease. This model was made as 
follows: A plaster jacket was applied to a patient 
and removed. After removal, the jacket was 
bandaged together and filled with plaster-of-paris 
paste, which hardened into a rough cast of the 
trunk. This cast was sawed in halves trans- 
versely, and by putting in some blocks of wood 
at the back to represent the vertebrae H—\i these 
two halves are placed as shown in the picture, the 
conditions of a case of mid-dorsal Pott’s disease- 
are fairly well represented (i). A Taylor back 
brace is applied by being bandaged to the lower 
segment and running up just as it would in the 
case of a patient. It is made to exert force at 
the point represented by the blocks of wood just 
as it would press forward upon the deformity. 
The upper part of the brace is bandaged to 
the top segment. These two segments of 
plaster represent the two segments of the body 
above and below the disease, and the problem is 
to determine what force must be applied by the 
brace to keep these segments in place. This 
would correspond to the force required to modify 
the intervertebral pressure, and this modification 
of the intervertebral pressure should be what the 
surgeon should strive to accomplish in all cases 
of Pott’s disease treated by this brace. 
The criticism may be made that this model 
does not reproduce the muscles. The only muscles 
which come in question are the intrinsic muscles 
of the spine, and those work to such a very great 
disadvantage in comparison with the leverage 
that the weight obtains, that they may be disre- 5 
garded as of practically little importance. They 
could have been represented by rubber cords run- 
ning along the back of this model, but it is evi- 
dent that such apparatus would have very little 
practical influence upon the experiment. The 
posterior muscles of the trunk may tilt the body 
backward, as often happens, but this acts only to 
bring the superincumbent weight further back, 
and will be discussed later. 
The upper part of this model weighs ten 
pounds, and a ten-pound weight is attached to it, 
which represents fairly well the conditions in a 
case of dorsal disease in a boy weighing forty 
pounds. An arm runs out from the back brace 
and other arms run out from the front of the 
upper part of the model. These are connected 
by spring balances, which show how much pressure 
is required at different levels. They show how 
much force will be required to hold the upper part 
of the model back. 
Three things can be demonstrated by this 
model: (i) If the chest is firmly held, and the 
pelvis is held with equal firmness, the pressure 
coming upon the spine over the disease, in case 
the brace were used to modify intervertebral pres- 
sure, would be so great that no skin would be able 
to stand it. If the finger is placed between the 
back brace and the wooden blocks in the model 
which represent the diseased column, it will be 
found that even when the upper segment only 
weighs twenty pounds the pressure cannot be 
borne. It simply demonstrates the necessarily 
incomplete action of the brace, for if it were pos- 6 
sible for the pelvis and chest to be held as firmly 
to the brace in the living subject as in this model, 
the skin would not be able to stand the pressure. 
It is obvious that the pelvis and chest cannot be 
held as firmly as in this model. (2) The position 
of the superincumbent weight is a most important 
matter. If the ten-pound weight is placed at A, 
that is as far back as possible, the spring balance 
at D registers ten pounds. If, however, the 
weight is placed at the forward part of the model, 
B, the balance registers nearly twenty pounds, 
demonstrating that the position of the superin- 
cumbent weight (that is, of the head and shoul- 
ders) is a most important matter in determining the 
amount of weight to come upon the diseased ver- 
tebrae. Therefore, if the head and shoulders are 
held as far back as possible in this way, it requires 
much less pressure to make the brace efficient 
than when the head and shoulders droop forward. 
(3) The level at which the backward pull is 
applied is a most important matter. In this 
experiment the spring balances are adjusted at the 
level of the axillae, j9, and the transverse pull is 
made practically at the level where would come 
the highest transverse straps of the apron. If the 
pull is made at a lower level in the model E, so 
great an amount of force is required to hold the 
upper part of the model in place that it cannot be 
registered by the balances in use. If the two arms 
are prolonged up to what would perhaps be the 
level of the middle of the face, C, much less force 
is required to hold the upper segment of the 
model in place than when pressure is made back- 7 
ward at the axillary line; that is, the higher the 
backward pressure is applied the less force is 
required to hold the upper part of the model in 
place. 
This model is not presented as an accurate re- 
production of the mechanical conditions in Pott’s 
disease, but to demonstrate certain obvious facts. 
The practical application of this experiment is 
as follows: In the living subject it is not possible 
to obtain a sufficiently firm hold upon the chest 
and pelvis. If it were, the skin over the deformity 
would not be able to stand the force required to 
modify intervertebral pressure. The Taylor back 
brace as ordinarily applied exerts no backward 
pull above the axillary line, where a very great 
force would be required to pull the upper segment 
of the body backward (Fig. 2). The chest piece 
of Dr. Taylor, which applies backward pressure in 
the fossae under the clavicles, is in the right direc- 
tion. The apparatus of Dr. Whitman (Fig. 3), 
which makes pressure upon the anterior part of the 
shoulders, is also in the right direction, but incom- 
plete and incapable of exerting proper pressure. 
If a firm hold could be obtained upon the chest, a 
brace would be able to accomplish much more 
than is found to be the case now. The chest piece 
used by the writer, which is practically an anterior 
brace to the chest, is shown in the diagram. It 
is an effort in the direction of obtaining this hold 
upon the chest, and is partly satisfactory. 
With regard to the mechanical efficiency of the 
plaster-of-paris jacket in Pott’s disease, a different 
method of experiment was undertaken. If the 8 
plaster jacket diminishes the deformity, or extends 
the spine when applied, it must necessarily cause 
lengthening of the body. If the plaster jacket can 
accomplish as much, or nearly as much as is done 
Fig. 2. 
by having the child lie on its back, the length of 
the child should be as much after the application 
of the plaster jacket, as when lying down. Some 
preliminary experiments were made with regard 9 
to the effect of recumbency in increasing the 
length of children with Pott’s disease, (i) A boy 
with lumbar deformity was one-quarter of an inch 
longer when lying down. (2) A girl with dorsal 
deformity was one-half of an inch longer when lying 
down. (3) A girl with lumbar deformity was 
one-quarter of an inch longer when lying down. 
(4) A girl with acute dorsal disease was seven- 
eighths of an inch longer when lying down. (5) 
A girl with high dorsal disease was seven-eighths 
of an inch longer when lying down. 
These experiments show that a child with Pott’s 
disease is from one-quarter to seven-eighths of an 
inch longer in recumbency than in standing. This 
difference can be accounted for by the change in 
the curves of the spine. 
An experiment was then undertaken to see if 
the plaster jacket caused lengthening of the child, 
and if so, under what circumstances. (1) Jacket 
applied by suspension. The immediate effect 
was an increase in the length of the child five- 
eighths of an inch over the standing position, but 
at the end of twenty minutes the child had short- 
ened three-eighths of an inch, and at the end of 
thirty minutes was back to one-eighth of an inch 
of the height when standing with no apparatus. 
In other words, the application of a plaster jacket 
lengthened the child only one-eighth of an inch. 
It may be mentioned incidentally that the child 
when lying on its back was one-half of an inch 
longer than when it was standing up with a prop- 
erly applied plaster jacket. (2) A jacket was 
applied to a child, with the effect of immediately lengthening it over the standing position. At the 
end of twenty minutes, the child was at the same 
height as when standing without the jacket on, 
and was seven-eighths of an inch shorter than 
when lying on the back in bed. The jacket was 
applied by suspension. (3) A jacket was applied 
by the hammock method: Standing without sup- 
port, 3 feet 2| inches; ten minutes after appli- 
Fig. 3. 11 
cation of jacket, 3 feet 2| inches; twenty minutes 
after application of jacket, 3 feet 2\ inches. (4) 
Jacket applied by the hammock: Standing with- 
out jacket, height 3 feet 4- inches; immediately 
after application of jacket, 3 feet 4| inches; ten 
minutes after application of jacket, 3 feet 4§ inches. 
In no one of the four experiments was the child 
substantially longer after the careful application 
of the jacket than when standing unsupported, 
and in no case as long as when lying down with- 
out apparatus. The column is longest and the 
spine consequently straightest when the child is 
suspended or has traction applied in bed to the 
legs and head. A boy with mid-dorsal disease, 
not very acute, was an inch longer in bed with 
traction than when he stood up. A girl with high 
dorsal disease and paralysis was lengthened three- 
eighths of an inch by traction over her length 
when lying quietly in bed. The spine is in its 
second best position when the child lies in bed 
without traction. The spine is shortest, and con- 
sequently in its worst position when standing, and 
the application of a jacket has not, in any case 
observed by the writer, been found to produce 
any permanent increase in height, except in one 
case where it lengthened the child one-eighth of 
an inch over the position without a jacket. 
The same may be said of the application of 
the antero-posterior brace. Recumbency, on the 
other hand, does produce such an increase in 
length. To the writer’s mind, the case is clear. 
Recumbency with traction is the best available 
treatment if we regard only the position of the 12 
spine. Simple recumbency is the next best. 
Treatment by ambulatory measures is the worst. 
These are demonstrated by the length of the 
child under these various conditions. 
Recumbency.—With regard to the treatment by 
recumbency I am as far as any one from wishing 
to advocate unnecessary recumbency, but I wish 
to go on record as advocating, in general, during 
the acute stage of Pott’s disease, recumbency on 
a frame for the greater part of the time, varied 
by short periods of going about protected by the 
most available brace or jacket. During the pain- 
ful stage I believe that recumbency should be 
continuous. The beneficial effect of recumbency 
must be familiar to every orthopedic surgeon, who 
must often notice the improved appetite, the in- 
crease in flesh, and the diminished fever, when a 
child with acute Pott’s disease is put to bed. 
In the use of apparatus it should be remem- 
bered that it is all necessarily imperfect from a 
mechanical point of view, and does not afford 
complete support, and that traumatism to the 
spine must result from the use of the jacket or 
the brace. The more complete and efficient the 
apparatus, the less the traumatism. 
Such are the scattered facts that I have brought 
together for your attention. Pott’s disease, it 
seems to me, is a very grave affection, and in ad- 
vocating its treatment by recumbency, rather than 
by ambulatory measures, during the acute stage, 
I am speaking of what I believe to be the very 
best treatment. Other modes of treatment are 
no doubt excellent, but when one wishes to secure the very best result, it seems to me that, having 
recognized that apparatus is intrinsically imper- 
fect, and necessarily so, to accomplish the purpose 
for which it is intended, it is incumbent upon 
the surgeon either to insist upon this treatment 
by recumbency or to transfer the responsibility of 
ambulatory treatment to the parents. The use 
of apparatus, it seems to me, should be during 
the acute stage, to vary the monotony of recum- 
bency. That recumbency should be carried out 
by having the child lie upon its back upon a frame. 
The addition of traction to the legs and head I 
believe to be of benefit, and that it hastens recov- 
ery by quieting muscular spasm and improving 
the position of the spine. I believe that it should 
be used in all cases of paralysis due to Pott’s 
disease. 
With regard to apparatus, whether we use it in 
the way that I have advocated or as the sole 
means of treatment, it seems to me that we should 
remember that apparatus is necessarily mechan- 
ically inefficient to solve the problem which it 
undertakes. If apparatus is used these points 
should be remembered: the position of the 
superincumbent weight should be as far back as 
possible, and the higher the backward pull comes, 
whether a jacket or a brace is used, the less force 
is required. 
Whether we wish to follow the best treatment 
or not may be a question, but it is the writer’s 
belief that treatment by recumbency, so preva- 
lent in the early days of orthopedic surgery, will 
come again to the front if the real value of sup- 
porting apparatus is studied. The Medical News. 
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