(2) In the second method, the procedure is the same as outlined above until
the contrast medium is pooled under the needle, but differs thereafter. When the
contrast medium has been pooled under the needle, the stylet is removed but, in this
case, no syringe is attached. Instead, the patient is instructed to do the Valsalva
maneuver in which he takes in a deep breath and carries out forced expiration against a
closed glottis. This aids in causing the contrast medium to flow out through the needle.
The maneuver is repeated until all (or most) of the contrast medium has been removed.
Before the needle is withdrawn, a radiograph, or a fluoroscopic examination should be
made to see if satisfactory removal has been accomplished. If satisfactory removal is
confirmed, the needle is withdrawn and the patient is returned to the ward.
Diskography is the radiographic investigation of selected intervertebral
fibrocartilages (disks) during radiopacification by a contrast medium. Examinations of
this type are normally done in the operating room or interventional radiology suite using
a C-arm. See figure 3-20.
a. Preparation of Patient Scheduling. The examination is scheduled
according to the established clinical procedure. Sedation is usually administered one
hour prior to the procedure.
b. Preliminary Procedure (Lumbar Diskography).
(1) When indicated, pre-injection radiographs are made of the area(s) of
(2) For lumbar diskography, the patient is usually placed on his side
(laterally recumbent) on a tilt-table unit with his body in flexion (as for routine spinal
anesthesia). In some instances, the examiner may prefer to have the patient placed in
the prone position.
The lumbar area is made aseptic and local anesthetic is administered.
(4) Under sterile precautions, the examiner inserts a No. 19 needle (1 1/2
inches long) in the midline aiming at the center portion of the intervertebral disk to be
punctured. A lateral projection is then obtained to check the exact location and
alignment of the needle.
(5) When it has been established that the No. 19 needle is properly aligned,
a smaller caliber needle (No. 22, 4 inches long) is inserted into the No. 19 needle. The
smaller needle is then advanced into the lumbar subarachnoid space. At this point,
cerebrospinal fluid may be withdrawn and collected for laboratory examination.