Discography is a diagnostic tool to evaluate the exact source of pain.
The disc is a unique structure between the vertebral column that bears the weight and allows the movement of spine. It is made of the nucleus in the middle and fibrous tissue surrounding it. The outer layer of annulus may crack (usually annular tear or fissure) under pressure or normal wear-and-tear. The nerve endings in the annulus may be irritated by the tear and usually are a source of discogesic back pain.
The center of the disc is filled with jelly-like fluid that may release chemicals to irritate surrounding nerve roots.
Most of the patients complain of low back pain that may radiate in the hip and legs. Pain is described as deep, aching, and nagging that gets worse with movement. If nerve root is irritated by chemical release, patient may complain of radicular pain radiating in lower extremities
Discogram is an invasive procedure with multiple risks. It is mostly used as a last resort tool to sort out the exact source of pain. If patient fails conservative treatment for back pain, including physical therapy, he may benefit from back injections like epidural steroid and facet injections. If patient fails above modalities of treatment for over six months, a surgeon may repeat discogram before contemplating a back fusion. If CT scan and MRI scan do not provide adequate information, a discogram may be warranted. Discography is a controversial amoung spine surgeon due to conflicting data on the usefulness of the procedure. Mostly, it is used as a last resort diagnostic tool before performing the fusion on the lumbar spine.
Patient is usually placed in prone position on the table. A light sedation is usually used before placing the needles in the disks to make it comfortable for the patient. When the position of the needles is confirmed under fluoroscopy, the dye is injected in each disk individually while patient is awake. The pattern of the dye spread is observed under fluoroscopy. At this time, I ask my patient if they experience any pain or just heavy pressure in the back. If they report pain, then I will ask them if this is their usual pain or a different type of pain. I will also ask my patient to quantify the pain intensity on a 0-10 verbal scale.
I cannot emphasize enough that the response to the above questions is critical in determining the future treatment plan. The patient should not display any level of anxiety at this juncture of time. They should not exaggerate their pain response. The patient should be very relaxed and calm and should accurately respond to the physician.
Based on the patient’s response, the exact level of fusion will be determined by the surgery.
A CT scan is usually obtained within 2-3 hours after the discogram. To get the pictures of the time and the pattern of the dye spread.
Some patients experience severe back pain during the injection into the painful disk. It is usually reported as a more painful procedure as compared to other back injections because the patient has to be awake during the procedure to answer the questions.