Overview of Percutaneous Vertebroplasty and Kyphoplasty
Osteoporotic compression fractures are a common type of fracture that affects people with osteoporosis, a condition that weakens the bones. These fractures can occur in the spine, even from minor injuries like sitting down too quickly. In people without osteoporosis, it would typically take a more major event, such as a car accident, fall, or jump, to cause these types of fractures. Sometimes, an infection or cancer can weaken the bones leading to a similarly easy fracture.
Compression fractures can cause significant challenges, such as back pain and difficulty with normal activities. Over time, these fractures can get worse. They can also increase the risk of additional fractures in nearby bones as the injured vertebral body transfers more load to the neighboring bones. Given how often these injuries happen, there are significant societal costs tied to this condition, as well as ongoing debates about the best treatment approach.
Vertebroplasty and kyphoplasty are two procedures that doctors use to treat these fractures. Both procedures involve injecting a type of acrylic cement known as polymethyl methacrylate (PMMA) into the fractured vertebra to provide support. However, these treatments have been controversial because studies haven’t shown that they consistently improve patient outcomes.
For instance, one study found that patients who had vertebroplasty experienced the same levels of pain and function as those who underwent a fake, or “sham,” procedure. Additionally, vertebroplasty has a higher risk of causing the cement to leak out into surrounding areas than kyphoplasty. As a result of these findings, doctors have started to opt for kyphoplasty as the principal procedure for treating osteoporotic compression fractures.
Anatomy and Physiology of Percutaneous Vertebroplasty and Kyphoplasty
As people get older, the density of their bones often decreases from its highest point. This can lead to a condition called osteoporosis, which means the bones are normal in quality but reduced in quantity. The inside of the bone, known as the cancellous bone, has fewer structures called trabeculae and thin outer bone layer, or cortical bone. This makes the bone more likely to fracture or break because it can’t handle as much pressure or weight.
One common type of fracture in people with osteoporosis is a vertebral compression fracture (VCF). This happens when the bone in the spine, or vertebra, can’t withstand the pressure from the body’s weight, causing it to collapse and lose about 20% or at least 4 mm of its height. The most often affected area is the thoracolumbar spine (the part of the spine where the chest and lower back meet) and the lower lumbar region (lower part of your back).
Compression fractures typically affect the anterior column of the spine, the front part of the vertebra and the ligament that runs down the front. These fractures are different from burst or Chance fractures because they don’t disrupt the posterior tension band, a collection of muscles and other structures at the back of the spine that keep it stable. So, compression fractures are considered stable fractures.
The posterior tension band includes the following parts:
- Posterior ligamentous complex: Upper and interspinal ligaments, yellow ligament
- Musculature: Muscles like the longissimus, iliocostalis, spinalis, semispinalis, rotatores, intertransversarii, and multifidus
- Bone: Parts of the spine including the transverse and spinous processes, pedicles, and facets
Why do People Need Percutaneous Vertebroplasty and Kyphoplasty
When someone has a vertebral compression fracture, which is a crack in one of the bones of the spine, they usually get better by resting, taking pain relievers, practicing physical therapy, and using a back brace. Often, symptoms improve over the course of 4 to 6 weeks. But in some cases, if the person is still in a lot of pain even after this period, a surgical treatment may be necessary.
The American Academy of Orthopedic Surgeon (AAOS) suggests that one type of surgery, called vertebroplasty, should not be used for these types of fractures. A different surgical procedure called kyphoplasty, however, is still considered as a good option for treating these injuries.
When a Person Should Avoid Percutaneous Vertebroplasty and Kyphoplasty
There are specific situations where certain procedures, like vertebroplasty and kyphoplasty, should not be carried out. Verterbroplasty and kyphoplasty are methods of fixing broken vertebrae, the small bones that make up your spine.
One instance where these procedures should not be performed is when someone has a compression fracture (a break in one of the vertebrae), but they don’t have any symptoms or pain. This type of fracture is often discovered by chance during a chest x-ray. If the fracture has already healed, the person wouldn’t benefit from any further treatment.
These procedures also should not be performed if a person has an ongoing infection in their body, like osteomyelitis or discitis. Osteomyelitis is a bone infection, while discitis is an infection in the discs between the vertebrae.
There are also some situations where the decision to perform the procedure is up to the discretion of the doctor. For instance, if the fracture extends into the back wall of the vertebral body (the main part of the vertebra), there’s a risk that cement used in the procedure can leak into the spinal canal. Additionally, if a person has very severe compression fractures or abnormal shaping of the vertebrae, this might serve as a relative contraindication, or reason to potentially avoid the procedure.
Equipment used for Percutaneous Vertebroplasty and Kyphoplasty
VP/KP (Vertebroplasty/Kyphoplasty) is a procedure used to treat spinal compression fractures. This process is best done using high-quality imaging, specifically through the use of a machine called C-arm fluoroscopy. This machine can take pictures of your spine from different angles, helping your doctor accurately guide the needle into the right position.
The procedure can be done with either one or two C-arm machines. If one is used, it will need to be moved back and forth between front-to-back (anteroposterior or AP) and side (lateral) views. Using two machines eliminates the need for constant repositioning, with one set for the front-to-back view, and the other for the side view.
Here are some of the tools your doctor may use during a VP/KP procedure:
- Fluoroscopy: This is an imaging technique that uses X-rays to obtain real-time moving images of the inside of your body.
- Spinal Needle: This is a long needle used to reach your spine.
- Spinal Needle Stylets: These are small, slender medical instruments used to probe or examine your spinal canal, they come in various shapes including diamond-shaped multi-bevel and single-bevel.
- Polymethacrylate (PMMA) Cement: This is a type of bone cement used to strengthen your spine.
- Kyphoplasty Balloon Catheter: This is a special type of catheter with a balloon on the end. It’s used to create a space in your spine where the PMMA cement is then injected. (Look at the detailed technique for more information)
Who is needed to perform Percutaneous Vertebroplasty and Kyphoplasty?
Vertebroplasty and kyphoplasty are two types of surgery that are mostly done by expert doctors who specialize in using imaging techniques to guide small tools inside the body (known as interventional radiologists), doctors who manage pain through procedures (called interventional pain management physicians) and specialists in surgery of nerves or the spinal column (neurosurgical/orthopedic spine specialists). During the surgery, other members of the medical team like a fluoroscopy technician (a person who operates a machine that creates real-time images of the body), a nurse, and a company representative may also be present. If a deeper type of sleep, known as general sedation, is needed for the surgery, a specialized doctor known as an anesthesiologist would also be there.
Preparing for Percutaneous Vertebroplasty and Kyphoplasty
Vertebroplasty and kyphoplasty, two procedures for treating spinal fractures, carry a moderate risk of bleeding according to the Society of Interventional Radiology (SIR)’s guidelines. So, before going through either procedure, it’s important for doctors to check the patient’s blood. This is often done by getting what’s called an INR and a complete blood count (CBC). Here are some specific recommendations:
* Make sure the INR, a measurement of bleeding risk, is less than 1.5
* If there are less than 50,000 platelets, tiny blood cells that help your body form clots to stop bleeding, a transfusion may be needed.
* ASA, a medication that can prevent blood clots, doesn’t need to be paused.
* Clopidogrel, another medication used to prevent blood clots and heart attacks, should be stopped for 5 days before the procedure.
* Low molecular weight heparin (LMWH), a type of medication used to prevent and treat blood clots, should be paused before one dose of the procedure.
Antibiotics are given to prevent any potential infections. An hour before the procedure, patients are usually given 1 gram of cefazolin via an IV.
During the procedure, the patient will be turned face down (prone) on a specially-padded table that allows doctors to see the spine with a fluoroscopic device also known as a C-arm. The C-arm helps to place the physician’s instruments in the right spot on the spine. The right position shows the spine straight on (AP position), and the ends of the bones are lined up with the beam from the X-ray.
Before the procedure starts, marks are drawn on the skin to help guide the surgeon, and the area is cleaned and covered to keep it sterile. The antibiotics are given right before the procedure to help prevent infections.
How is Percutaneous Vertebroplasty and Kyphoplasty performed
Vertebroplasty (VP) and kyphoplasty are medical procedures that help strengthen and stabilize bones in your spine. They are pretty much the same, except that with kyphoplasty, a tiny balloon is used to create a pocket inside the bone that is then filled with cement. It’s a bit like a mini construction site in your back!
To perform Vertebroplasty the doctor will make a tiny cut on your back over a section of your spine called the pedicle. They then use a special camera called a fluoroscope to see exactly what they’re doing. Once they’ve made the cut, they use a hollow needle, which is slid into place through the tiny hole. They keep checking the needle with the fluoroscope as it slides in, to make sure it’s in just the right spot. It’s important to get the needle exactly right to prevent any kind of nerve damage.
The pointy end of the needle needs to be placed close to the middle of the vertebra (the technical name for the bone in your spine). It has to sit in the front 1/3rd part of the vertebra to avoid any damage. The perfect positioning of the needle is confirmed with the camera.
If it’s a kyphoplasty, a balloon catheter (a thin tube) is put inside the needle, and then inflated to make a little bubble or cavity. The balloon is carefully filled until it touches the surface of the bone, or restores the bone to its original height, it’s then deflated and taken out.
The cement is then filled into the hollow needle. It needs to be thick, like the consistency of a paste, so it doesn’t leak. This cement is carefully delivered into the bone to fill up the space. The doctor uses the fluoroscope to make sure the cement is going into the correct area and doesn’t go anywhere it shouldn’t. The doctor keeps adjusting the needle and the cement until it is evenly distributed throughout the bone. The cement is then left to firm up. When everything’s done, the needle is removed carefully to avoid leaving any cement behind.
What’s great about this procedure is that it can greatly improve your back’s stability, relieve pain, and help fractured or damaged bones heal quicker.
Possible Complications of Percutaneous Vertebroplasty and Kyphoplasty
About half of the people who undergo a procedure called vertebroplasty might experience complications, but the good news is 95% of them might not feel any symptoms. Here are some common complications:
– Infection and bleeding: Like any procedure, there’s always a risk, although usually small, of catching an infection or bleeding.
– Nerve or spinal cord damage: During the procedure, a needle is placed into your spine. If the needle accidentally punctures certain walls of the backbone, it might lead to damage to a spinal nerve or even the spinal cord, causing symptoms like pain or weakness in certain parts of the body.
– Leakage of PMMA: The most common issue with vertebroplasty is that a certain substance called PMMA, which is injected into the spine during the procedure, can accidentally leak out into surrounding areas and into the spinal canal. This is more likely to happen during vertebroplasty than during a similar procedure called kyphoplasty because no space is created to accommodate PMMA in vertebroplasty and a higher pressure is needed to inject the substance.
– Rare complications: In rare cases, the particles of PMMA can enter a vein and travel to your lungs, which can cause a blockage. Another rare but serious complication happens when cement leakage narrows the spinal canal, a condition known as iatrogenic spinal stenosis. This can cause symptoms such as pain, numbness, and muscle weakness.
What Else Should I Know About Percutaneous Vertebroplasty and Kyphoplasty?
When older people suddenly get a back fracture, it can be extremely painful and can stop them from moving. There have been several studies that show significant relief of pain, improved lifestyle, less reliance on strong pain medications, and better ability to move in people who have surgical treatments such as vertebroplasty and kyphoplasty. Both these procedures help to repair the broken vertebrae in the spine.
In plain words, if someone has a painful back fracture that isn’t getting better with regular medical treatments, these surgeries can be very effective. However, it’s always necessary to weigh up the risks and benefits before deciding on surgery. Following the guidelines set by the Society of Interventional Radiology (SIR) will ensure the best possible care.
