Definition and Overview
Also referred to as discography, a discogram is a procedure that involves the use of a contrast dye and an imaging machine (such as an MRI scanner or X-ray) to diagnose conditions that affect the spinal disc. It is based on the concept of fluoroscopy, an imaging technique that uses X-ray to create real-time pictures of moving structures in the human body.
The spine, which is also called the backbone, is the part of the body that runs from the tip of the skull down to the pelvis. It is composed of 33 vertebrae placed on top of each other, which is why it's also called the vertebral column. The columns are divided into three major sections depending on their location: cervical (neck), thoracic (chest) and lumbar (lower back). In between the vertebrae is the intervertebral disc, which is shaped like a doughnut with a jelly-like filling.
While the vertebral column protects the spinal cord, the bundle of nerves serves as a communication pathway between the brain and the rest of the body. The intervertebral discs, on the other hand, work as shock absorbers for the spine so it will not be easily damaged in cases of traumatic injuries. However, just like other parts of the body, the discs can also suffer from a variety of conditions that can affect the spine and lead to chronic pain.
In such cases, a discogram is performed to verify the source of the pain so the most appropriate treatment protocol or pain management plan can be devised.
Who should undergo and expected results
As a spinal disc diagnosis tool, a discogram may be recommended if the patient complains of neck and/or back pain. The procedure is invasive and only recommended for patients who have gone through multiple physical and imaging tests and have been given medications and treatments but still did not experience pain relief.
In many cases, pain in the neck and back is due to damage to the discs or aging. When the discs are damaged due to pressure build up, they can bulge out or became herniated leading to painful or pinched nerves. The condition can also be caused by aging, which causes the natural, gradual degradation of the bones and discs. Regardless of the cause, the pain around the neck can radiate to the shoulders and arms while that of the back may be felt all the way to the thigh and pelvis.
A discogram is also considered before a spine fusion surgery, an invasive procedure that stops the movement of a problematic vertebra by connecting it to a stable or non-moving bone. The procedure is performed so the spine surgeon can identify the discs that have to be removed.
As an invasive procedure, a discogram is typically not recommended for pregnant women while breastfeeding mothers can undergo the procedure so long as they don't feed their baby with their milk a day or two after. People with bleeding disorders, blood clotting problems, and kidney issues may also be prohibited from undertaking the exam.
A discogram is actually a controversial procedure since it doesn't always provide conclusive results. Thus, it is often complemented with other tests like MRI. This leaves many health experts to question the necessity of the procedure.
Patients should also note that this is only meant for diagnosis and that it doesn't treat or improve pain.
How the procedure works
This spinal disc diagnosis is performed by a radiologist or a doctor who has considerable knowledge in radiology, including conducting the procedure and interpreting its results.
Before the test, the patient has to go through a comprehensive physical exam and blood test to determine the presence of underlying conditions that could affect the result of the procedure or could lead to serious complications. Kidney function will also be checked to ensure that the organ can safely and quickly eliminate the contrast dye from the body in the form of urine. The patient may also have to fast a day before the procedure.
The test is done on an outpatient basis in a fully equipped specialty clinic or hospital. Once the patient arrives, a nurse does the preparation including changing the clothing into a hospital gown and inserting an IV line into the hand's vein to deliver the sedative. General anesthesia is not given since the patient may be required to answer questions during the test.
The patient is then assisted to an examining table where his back is exposed so the outline of the spine can be easily seen. Based on the imaging records and the patient's general complaint, the doctor then identifies the part where the contrast dye, usually with antibiotics, should be placed. The patient's vital signs like heart rate and blood pressure are monitored throughout the procedure.
The area is first cleansed and shaved before local anesthesia is administered and the contrast dye delivered through the IV line. The dye is supposed to mimic what normally happens during a painful episode and the patient is encouraged to report such during the procedure. In the majority of cases, multiple contrast dye injections are performed before the problematic disc is identified. Each injection is typically provided in a 25-minute interval and the entire procedure takes about an hour. Once the problematic disc is identified, an MRI test will be performed to assess its condition. Depending on the result, the doctor can come up with a diagnosis and/or possible treatment.
Possible risks and complications
There will be discomfort and pain during the procedure since the contrast dye causes buildup or increased pressure on the disc. However, the pain may be different from what the patient usually experiences. The pain may also be felt within 24 hours after the procedure.
Other potential complications are nausea, bleeding, and infection at the injected site or the disc. In rare cases, it may result to damage to the nerves, paralysis and general muscle weakness. The patient may also develop allergic reactions to the dye or anesthesia used.
Gardocki RJ, Camillo FX. Other disorders of the spine. In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics. 12th ed. Philadelphia, PA: Elsevier Mosby; 2012:chap 44.
Lauerman W, Russo M.Thoracolumbar spine disorders in the adult. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic Sports Medicine. 4th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 128.