(3) The head-end of the table is now raised approximately 10 to 20 degrees
from the horizontal (figure 3-18). If the patient is lying on his side, he must be adjusted
in the prone position. The injection site is covered with sterile gauze or a towel. The
fluoroscopic apparatus and spot-film device are then brought into operative position
over the injection site. Proper precautions must be taken to avoid disturbing the
position of the needle. The specialist should be sure that the fluoroscopic apparatus is
locked and the locking mechanism is absolutely safe. In some instances, a safety-bar
may be used as an additional safeguard. The safety-bar may be contrived of an
ordinary piece of wood or metal that is sturdy enough to serve the purpose. It is
advisable to have safety-bars made up in several lengths to accommodate patients of
varying sizes. If necessary, the safety-bar can be tied, taped, or clamped onto the
upright support assembly that maintains the fluoroscopic apparatus and spot-film
device.
(4) Fluoroscopy and spot-film radiography are then carried out. In some
instances, however, the examiner may forego the latter aspect of the examination and
proceed to inject the contrast medium instead.
(5) A syringe filled with the contrast medium (3 to 4 cc) is attached to the
needle. The subsequent steps of the procedure depend upon the amount of contrast
medium (with specific reference to Pantopaque) used.
e. Technique in Which a Relatively Small Amount (2 to 6 cc) of Contrast
Medium is Used.
(1) After the introduction of the contrast medium into the subarachnoid
space, the syringe is disengaged from the needle, the stylet is replaced, and the
injection site is covered with sterile gauze or a towel. The bolster is removed from
beneath the abdomen and placed under the patient's lower extremities, as needed.
(2) The fluoroscopic apparatus and spot-film device are brought into
working position over the injection site. The apparent shape, location, and behavior of
the body of injected contrast medium is studied by the examiner under fluoroscopic
control as the table unit is raised or lowered according to his instructions. The position
of the patient in relation to the tabletop may be changed at intervals. For example, the
patient may be obliqued either to the right or the left, or postured on his side. In
handling the patient, great care must be taken to see that the needle does not hit the
fluoroscopic apparatus.
(3) Spot-film exposures are made at various intervals and in different
positions. The patient should be instructed beforehand that he is to immediately
suspend respiration at a given signal from the examiner or the specialist. In addition to
the spot-films, PA (figure 3-19) and lateral projections (figure 3-20) may be made
without changing the position of the patient. For the lateral projection, a horizontal CR
is preferable. Spot obliques and/or stereoscopic exposures are made as indicated by
the examiner.
MD0959
3-50