Discography in addition is labeled as discogram is presently used to establish whether the disk is the cause of pain in patients with primarily axial back or neck pain.
Specific indications for discography include the following:
- Relentless, acute symptoms when other tests have unsuccessfully determined a suspected disk as a source of the pain
- Assessment of abnormal disks or recurrent pain from a previously operated disk or lateral disk herniation
- Examination of patients in whom surgery has failed, to establish whether pseudoarthrosis or a problematic disk in a posteriorly viewed segment could be the cause of aches, soreness, throbbing back pain
- Inspection of disks preceding fusion to establish whether the disks of the anticapated fusion segment are symptomatic and whether the disks adjacent to this segment can support a fusion
- Evaluation of approved patients for minimally invasive surgery who have a confirmed disk herniation
Theoretically, discography may provoke pain due to the following reasons:
- Contrast material injected into the disk may increase intradiscal pressure. In an atypical disk, stretching of the annular fibers of the disk may excite nerve endings.
- Biochemical or neurochemical stimulation that causes pain may be the result of an injection.
- Pressure at the end plates because of injections may be transferred to the vertebral body throughout the end plate, resulting in an increase in intra-vertebral pressure. This notion is supported by studies reporting disk injection resulting in end-plate deflection and augmented specimen height.
- The occurrence of pain on injection of a disk that is assumed normal may be due to transfer of pressure from the injection to an irregular, symptomatic adjacent disk, hence eliciting a positive pain response.
Discographyshould be completed only if sufficient attempts at moderate therapy and noninvasive diagnostic tests, such as MRI, have failed to expose the etiology of back pain.
Technique for Discography Diagnostic Procedure
- Prophylactic antibiotics should be taking into account
- Double-needle technique always should be utilized.
- Water-soluble contrast medium should be used when injection is performed.
- Precise needle placement is required to prevent annular injections, which could create false-positive results.
- Injection against the vertebral end plate can generate a false-positive response.
- Discography should be followed by CT scanning.
The information recorded should include the following:
- Resistance to the injection (ie, end point)
- Amount of contrast material injected (ie, maximum volume)
- Volume at which the patient experienced pain (ie, pain volume)
- Pattern of dye distribution (eg, diffusion, location of fissure, extravasation, herniations, Schmorl nodule)
- Pressure at which patient experienced “pressure sensation”
- Pressure at which patient experienced “pain”
- Pain response (ie, location, character, distribution, intensity, and concordance or discordance with the patient’s typical pain and pain pattern)
- Pain intensity recorded on a 0-10 scale