Overview of Fluoroscopy Discography Assessment, Protocols, and Interpretation
Lower back pain (LBP) is a widespread health issue that affects about 577 million people or 7.5% of the global population. It has been the leading cause of disability for many years, especially in the United States among adults. LBP can become more prevalent as people age.
The connection between lower back pain and leg problems was first suspected by ancient Greeks and Egyptians. However, our current knowledge about lumbar disk herniation (the condition where a disk in your spine protrudes and causes pain) wasn’t fully developed until the mid-1700s. In 1932, the first surgery for this condition, known as a lumbar discectomy, was performed. Over the years, diagnostic techniques have evolved considerably. One such technique, discography, gauges the health of your spinal discs and was first described in 1948.
Nowadays, modern diagnostic procedures like Magnetic Resonance Imaging (MRI) can identify multiple levels of spinal disc degeneration (wear and tear on the discs in your spine), which may or may not be related to back and leg pain symptoms. As we get older, especially men, the loss of a type of protein called proteoglycans from the disc increases. This means around 10% of 50-year-olds and 60% of 70-year-olds have severely worn-out discs. However, it is hard to determine if the identified conditions are indeed the source of pain or just age-related changes in the spine.
An examination method called provocative discography can potentially answer this question. It helps find out if pain is originating from a degenerating disc in the spine. Two main types of disc degeneration exist – one that involves defects and inward collapse in the disc’s outer layer and another that involves a tear or protrusion in the disc.
It’s important to note that discogenic lower back pain (pain originating from a degenerating disc) can be diagnosed with MRI but cannot replace discography as the most credible diagnostic procedure. There are times when a patient with lower back pain has an MRI, but it doesn’t clearly indicate any structural abnormalities in the spine. In such cases, discography may provide valuable insights and play an essential role in diagnosing the patient’s source of pain.
Aside from the disc, other structures in the back can also cause pain. It becomes challenging to identify which parts are involved. These can include the facet joints, nerves, endplate (a section of the vertebra), and sacroiliac joint (a joint near the bottom of your spine), etc. In some cases, an injection known as a “sham” injection can help identify if the patient’s complaints are legitimate.
Also, discography can guide surgical decision-making. However, this procedure can be uncomfortable, and special attention to patient’s overall health, especially heart health and kidney function, should be considered given the potential risks of the procedure.
In the context of emerging regenerative medicine treatments, like platelet-rich plasma and other “stem cell” therapies, discography has proven helpful in planning for these treatments. Some minimally invasive treatments such as endoscopic diskectomy and procedures involving heat often require discography before they are performed.
Discography is classified into two systems – the original and the modified Dallas discogram. The original Dallas classification was developed when CT scans were not available and is graded from 0-3, with 0 indicating a healthy disc and 3 indicating a severely damaged disc with contrast dye leaking beyond the outer disc layer. The Modified Dallas discogram, on the other hand, gauges the severity of tears on CT imaging through the disc itself, with Grade 0 signifying a normal disc and Grade 5 (termed ‘evil’ grade) indicating a highly damaged disc where contrast material leaks out of the disc, potentially causing direct irritation to the nerve roots.
Anatomy and Physiology of Fluoroscopy Discography Assessment, Protocols, and Interpretation
The intervertebral disc (IVD), a crucial part of your spine, is somewhat like a sandwich with a soft filling (the nucleus pulposus) that’s encased in a tougher shell (the annulus fibrosis). The “bread” of this sandwich is called the cartilaginous endplate, made from a type of cartilage called hyaline. This layer is responsible for securing the disc to the vertebrae (bones of the spine) above and below it, and it also helps distribute nutrients to the disc.
Typically, a healthy IVD has few nerve endings, most of which are associated with the region around the blood vessels. These nerve endings are also located around the rim of the annulus fibrosus. This is essential information for medical procedures like discography (a diagnostic test for back pain), as it helps determine which classifications of spine condition might cause pain.
The vertebral body (the main part of the vertebra) itself doesn’t have many nerve endings, which are mostly found near the blood vessels. It is interesting to note that in cases of certain spinal conditions triggered by “endplate failure,” the endplates display more nerve endings than usual.
As you age, your intervertebral disc might lose its height, and the endplates could start showing irregularities. This could also happen due to spinal degeneration and could lead to what’s known as “Modic endplate changes.” However, it remains unclear how these alterations affect discography results. It’s also worth mentioning that the combination of the diminishing disc height, the fading definition of endplates, along with an increase in size or “hypertrophy” of the facet (a joint in the spine), might make some discs unsuitable for discography.
Why do People Need Fluoroscopy Discography Assessment, Protocols, and Interpretation
If you’re experiencing severe back pain, your doctor might suspect that it’s coming from the spinal discs, the pads that act as cushions between the bones of the spine. If your pain is severe enough, they might consider surgery or pain management techniques designed to target these discs. There are various strategies that can be used, including a procedure to remove portions of a disc (endoscopic discectomy), treatment that uses heat to destroy nerve fibers in a disc and reduce pain (electrothermal therapy), or the use of radio waves to reduce pain (posterior annular zone radiofrequency ablation).
This might be the case if your pain hasn’t improved with coping strategies or treatments you’ve tried so far, if your pain has lasted for at least three months, and if there isn’t evidence suggesting other problems that need to be addressed first, such as severe narrowing of the spinal canal (spinal stenosis), infection, or pain that’s more mental or emotional than physical (psychogenic pain).
In some cases, a discogram can help differentiate between pain caused by a false joint (painful pseudoarthrosis) or a damaged disc in a portion of the spine that’s been previously fused with surgery. The procedure can also assess the health of a disc before spinal fusion surgery – a procedure that permanently connects two or more bones in your spine.
Even though a discogram is generally considered when surgery is an option, it can also help diagnose pain conditions that might be confused with pain originating from organs such as those in the abdomen or pelvis. So, if you’re experiencing atypical abdominal or pelvic pain, this procedure may be beneficial.
When a Person Should Avoid Fluoroscopy Discography Assessment, Protocols, and Interpretation
There are certain conditions that may prevent a patient from undergoing lumbar discography, a procedure used to identify the source of back pain. These conditions include:
* If the space between the patient’s spinal bones (vertebral body) has previously been fused or joined together at the level where the procedure is to be performed.
* If there’s pressure on the spinal cord or the groups of nerves at the end of the spinal cord (cauda equina/conus medullaris) at the level where the doctor plans to work.
* If the patient has a systemic infection (an infection throughout the body) or an infection of the skin where the doctor plans to insert the needle.
* If the patient is known or suspected to have infectious discitis, an infection of the spinal discs.
* If the patient has had a specific type of spinal fusion where, due to changes in the anatomy, disk entry is not possible.
There are also some general conditions that can prevent a patient from undergoing similar procedures to manage pain:
* If the patient has a bleeding disorder that is not under control or is taking medication to prevent blood clots (anticoagulation therapy).
* If the patient is pregnant.
* If the patient is allergic to a substance called iodine contrast (although a different substance called gadolinium can be used in these cases).
* If the patient has severe kidney problems.
* If the patient has unstable heart conditions or uncontrolled high blood pressure that could result in serious heart events like an irregular heartbeat (arrhythmia) or lack of blood supply to the heart (ischemia).
* If the results of the procedure will not change the patient’s treatment plan.
* If the procedure needs to be done with pressure readings (called manometer readings) and a manometer is unavailable.
Additionally, there are overall health conditions that can prevent any medical procedure:
* If the patient is unable or unwilling to give consent.
* If the patient is not able to make medical decisions for themselves (not competent to consent) and there is no one available with the legal authority (medical power of attorney) to make decisions for them.
* If the patient has mental health conditions that are not under control or not treated.
Equipment used for Fluoroscopy Discography Assessment, Protocols, and Interpretation
Here’s a list of equipment that your doctor might use if you’re having a provocative diskogram, which is a test to find out if your back pain might be caused by a disc in your spine:
- A fluoroscopic C-arm x-ray device: this is a flexible and moveable x-ray machine that your doctor will use to clearly see your spine during the procedure.
- Lead aprons: these are used to protect everyone in the room from unnecessary exposure to x-rays.
- A circulating medical assistant: this person is on hand to help the doctor during the procedure.
- Different types of needles: these are used to apply local anesthesia to numb your skin and deeper tissues as well as to enter the disc in your spine.
- Local anesthesia: this is a medication to numb your skin and the area where the doctor will be working.
- Injectable antibiotics: these help prevent infection. If you’re allergic to the usual antibiotics, the doctors have alternatives they can use.
- Myelogram grade contrast agent: this is a special dye that is injected into your spine so that the doctor can see your spinal cord and nerves more clearly on the x-ray images.
- The doctor will do a pregnancy test if needed.
- Sterile gloves, drapes, and gauze: these items help keep the procedure sterile and prevent infection.
- Short IV-extension tubing
- Antiseptic solution: this is used to clean the skin before the procedure.
- If manometry is needed (which measures pressure), the necessary equipment will usually come in a sterile kit.
If the doctor needs to use light sedation (meaning you’ll be awake but very relaxed), they’ll have standard monitoring equipment to keep an eye on you and specific drugs to help you relax. The equipment that they would need to help you, in the case of an emergency (a so-called “code-cart”), will also be available. There will be trained personnel there specifically to monitor and record your sedation.
If a CT scan is needed after the procedure, the doctor will have a plan in place to get you safely to the scanner.
Who is needed to perform Fluoroscopy Discography Assessment, Protocols, and Interpretation?
A doctor, known as a physician, will do a procedure called a discogram. A discogram is a type of X-ray test that helps to find out if a specific disc in your spine could be causing your back pain. In the procedure, the physician gets help from a radiology technician, who is like a special helper, to manage special equipment used in the procedure, like the C-arm or a CT scan if needed.
Also, there’s a medical assistant present in the procedure. This person assists the physician with tasks such as arranging instruments and keeping the operation field clean and safe.
In some cases, if the patient needs to be moved for a post-discogram CT scan, there will be a transporter or escort to assist in safely moving the patient.
If the doctor uses an IV to give medication that makes you sleepy (sedation), there will be a trained observer. This person’s job is to monitor and record vital signs like your heart rate and blood pressure. The person who gives you the sedation medication could be a nurse or an anesthesiologist (a doctor who specializes in giving anesthesia), depending on the rules of the hospital and the state.
All these professionals work together to ensure your safety during the procedure. If there’s any emergency, like a reaction to the medication or trouble with your breathing or heart, there are sufficient personnel present to manage the situation and give immediate assistance.
Preparing for Fluoroscopy Discography Assessment, Protocols, and Interpretation
Before conducting a medical procedure, it’s crucial that the doctor fully explains to the patient what the process entails, why it’s necessary, and what the potential risks and benefits are. This discussion should ideally take place in the doctor’s office, days before the procedure, so that the patient has ample time to comprehend the information and ask any questions without feeling anxious about the impending procedure. To help clarify things, the doctor may use images or models of the spine.
If the patient is a woman who could potentially be pregnant, she would be asked to take a pregnancy test or sign a waiver.
Your doctor will also need to check your medical history, especially if you’re on any blood-thinning medication or if you have any heart issues. They will make sure any medication you’re taking won’t interfere with the procedure, and if needed, they may ask for more tests to make sure it’s safe for you to proceed with the procedure.
Before the procedure begins, an IV (a small tube inserted into your vein) will be placed. This is done to administer any necessary medication, including light sedative to help you relax, or antibiotics to prevent infections. Your vital signs like heart rate, blood pressure, and oxygen level will be continuously monitored to ensure everything is going fine. You will be asked to lie face down on a specialized X-ray table.
Before starting, a crucial safety step called ‘Time-Out’ is followed where the medical team jointly verifies the correct patient, procedure, and the location on the body where the procedure is to be performed. They will also discuss and confirm any further steps, for instance, if a CT scan is planned afterwards.
The procedure might slightly vary depending on your body structure. For men, one specific area of the lower spine (the L5/S1 region) might be more difficult to access due to its location. In certain cases, you might be positioned in a particular way to make the procedure easier. The medical team will make sure this is known and the positioning is checked before they clean and prepare the area for the procedure.
If antibiotics are used, they may be mixed into a saline solution and given to you via the IV line. However, it’s important to note that experts do not entirely agree on the necessity of antibiotics for prevention of discitis, an inflammation of the intervertebral disc.
Members of the medical team, including the doctor performing the procedure, will be wearing protective gear, including lead aprons and sterile gloves. Certain instruments might be used based on the manufacturer’s instructions.
The procedure might involve using a needle to access the disc in the spine, which may be inserted through a larger needle. This needle may be slightly curved for improved maneuverability, and will be filled with a contrast material that helps to highlight the area in X-ray images. This helps the doctor to accurately perform the procedure.
How is Fluoroscopy Discography Assessment, Protocols, and Interpretation performed
Once everything is set up and the patient is lying on their stomach, the first step is to identify the specific spot on the lower back that will be worked on. Not all discs in the spine can be accessed from both sides. The side chosen by the doctor depends on whether they are right or left-handed, personal preference, the arrangement of the room, and how flexible the equipment setup is.
Next, the area is cleaned with a special antiseptic solution called Chloraprep, and covered in a sterile cloth with a window, or ‘fenestration’, over the target area. An X-ray marker is placed roughly in the middle of the lower back as a reference point, and an X-ray is taken. This marker may be moved for better alignment if the first estimate isn’t quite right. The X-ray machine, called a C-arm, is then angled for a clearer view of the exact spot from the side.
Injecting the needles too far to the side, especially on a side where the spine is twisted forward, requires care. In these cases, it might be best to approach the disc from the other side. A local anesthetic, usually lidocaine, is used to numb the skin. An 18-gauge needle (a larger needle) makes an initial access point through the skin. Then a smaller 22-gauge needle is inserted into the disc through this larger needle. Additional lidocaine is given as need to numb the area further as the needles are positioned correctly.
When the needle is in the right position, it is typically rotated for a better view of the back and front parts of the disc and the spinal canal. The needle itself is left where it is, while the inner part, known as the stylet, is removed. The needle receives an extension attached to a syringe that will inject a dye into the disc. Now, the doctor is ready to inject, or “provoke,” the disc to see how it will react. Some “fake” injections might be performed to get an idea of how the patient might react to non-provocative circumstances.
Good communication from the doctor is crucial during this process. The patient is told to prepare for a sense of pressure and potentially some pain. The doctor will typically ask the patient about the pain, including where it’s located and how intense it is. The terms “concordant” and “discordant” are often used to describe whether this pain matches the pain the patient usually experiences.
The dye is then injected into the disc while its spread is visualized with the X-ray machine. If using a manometer, which measures pressure and volume, the initial measurements at the beginning of the injection are recorded. The pressure is increased gradually and the change in pain location and intensity is continually noted throughout the procedures. This will help to identify different stages of potential disc problems.
The doctor finishes with one disc before moving on to the next to prevent confusion between the individual discs. Some doctors may inject a small amount of a pain reliever, like bupivacaine, into the most painful discs to ease post-procedure discomfort. Care should be taken to avoid injecting into a blood vessel by accident.
When all the necessary discs have been injected, final X-rays are taken, the antiseptic solution is cleaned off, and a clean, dry bandage is applied to the patient’s lower back. The intravenous line is removed only after the patient is stable and off the procedure table.
If the procedure is done with two X-ray machines set up at right angles to each other, an side view might not be available and the front and side view X-rays need to be taken together. This gives the doctor a virtual 3D image, but requires skill to interpret correctly.
Possible Complications of Fluoroscopy Discography Assessment, Protocols, and Interpretation
Although discography complications are uncommon, they do exist and can include:
* Discitis, an inflammation of the disc space between the bones in your spine
* Meningitis, an infection of the membranes covering your brain and spinal cord
* Nerve root injury, a condition that affects the nerves coming out from the spinal cord
* Superficial infection, which is an infection on the surface of your skin
* Skin irritation caused by the solution used to clean the skin
* Medication reaction, possible negative effects from medicines
* The effects of stress on your heart during the procedure
* Kidney injury caused by the contrast material used to help see your discs better (this damage might show up later)
* Vascular injury, damage to your blood vessels
* Bleeding
* Increased pain
* Disc herniations, when a disc in your spine slips out of place
Patients should be able to communicate with the doctor performing the procedure, despite being under light sedation, that can aid in managing any discomfort. However, this light sedation also includes its own risks such as possible reactions to medication, and significant sedation presenting its own risks to respiratory and/or heart functions.
What Else Should I Know About Fluoroscopy Discography Assessment, Protocols, and Interpretation?
Discography is a procedure where a doctor tests the discs in your spine to help find the cause of your back pain. It might be uncomfortable to go through, but it is generally safe when performed by an experienced doctor. This test can be useful whether your pain is localized to the spine (axial spine pain) or if it’s spreading out to your arms or legs (radiculopathy).
After the discography, another test called a CT scan might be done. That’s essentially an X-ray that creates detailed images of the inside of your body. This can be particularly handy if you can’t do an MRI, which is another type of imaging test. Sometimes, a CT scan proves to be a better choice to diagnose certain issues, like tears in the back part of the disk (posterior annular tears).
Remember, the discography is only for diagnosing your problem, it’s not meant to treat your pain. Its use in specific conditions, like when the plates at the end of the vertebrae are causing degradation, is still unclear. One major benefit of this procedure is that it can help avoid unnecessary surgeries, especially complex ones where the vertebrae are joined together. So when used correctly, it can be vitally important.