Overview of Vertebral Augmentation
A vertebral compression fracture (VCF) is a type of broken bone in the spine. It is the most usual issue people face related to osteoporosis, a condition where your bones become weak. Each year, about 1.4 million people around the world experience this. If we take a closer look, we can see about 20% of people over 70 years old are dealing with these fractures because of osteoporosis. The probability is slightly less, around 15%, for women who have gone through menopause. In the United States alone, 750,000 new cases of VCF arise every year, it’s especially common in people with osteoporosis, cost about $1.2 billion in medical charges.
These fractures can gradually get worse, creating a higher risk of further damage. It’s important to note that having a VCF can mean a five times higher chance of getting more fractures. This, with the fact that the likelihood of passing away in the first year after a fracture increases, is quite concerning. Nonsurgical treatment often does not help much and can even lead to more health issues and spine deformities. Research has shown a significant risk of dying within a year, from 2% to 42%, in patients who didn’t go through surgery. When combined with osteoporosis, not treating it surgically can lead to a domino effect of more spine deformities, ramping up the costs and affecting people’s social lives.
On a brighter note, vertebral augmentation (VA) is emerging as a better solution. This is a type of surgery to restore the height of the vertebrae (the bones in your spine), improve the alignment of your spine, and relieve pain. What’s even better, VA can lessen the risks associated with long term bed rest and spine deformities, such as problems affecting lung function, pressure sores, and serious blood clots. This underlines VA’s powerful role in handling VCFs, giving a more complete and effective method to deal with all the challenges osteoporosis can bring about.
Anatomy and Physiology of Vertebral Augmentation
The human backbone, or spine, consists of 33 individual bones known as vertebrae. These vertebrae are stacked one on top of the other, forming a complex and efficient structure. The lower part of the spine, which has 5 vertebrae, is often affected by compression fractures, sort of like tiny breaks or cracks in the bones, which require medical treatment.
Between each vertebra, there are soft circular pads called intervertebral discs that act like shock absorbers to avoid the bones rubbing against each other. Each vertebra has various smaller parts. The back part of a vertebra has a bony outgrowth that you can actually feel if you press on the middle of your back. Connected to this are two more small bony parts, which connect the bigger bone of the vertebra to the rest of the vertebra’s structure.
Inside the vertebrae, there’s a hollow space where the spinal cord, which is about as thick as an adult’s thumb, runs from the base of the brain to the top of the lower spine. After this point, the spinal cord splits into many separate nerves. There are 31 pair of these spinal nerves that come off of the spinal cord and exit the spine at the sides. They are named and numbered based on their location: 8 in the neck area (cervical), 12 in the chest area (thoracic), 5 in the lower back (lumbar), 5 in the pelvic area (sacral), and 1 in the tailbone area (coccygeal).
Each vertebrae is connected to its neighbors by four small joints, and a chain is formed up and down the spine. Along with these joints, major muscles and three main ligaments (strong bands of tissue) help keep the spine stable and prevent the vertebrae from moving around too much. These ligaments and muscles, along with the vertebrae and discs, all work together to ensure the spine can do its job efficiently.
Why do People Need Vertebral Augmentation
Various studies in the medical field have noted that Vertebroplasty, a type of spinal surgery, is recommended in certain situations. This treatment is often not beneficial for fractures that have persisted for over six months.
Some of the situations when Vertebroplasty is suggested include the following:
- Severe spinal fractures due to weak bones (osteoporosis) causing pain that won’t relieve with rest, medication, wearing a supportive brace, physical therapy, gentle exercise, or nerve root blocks.
- Routine pain due to tiny fractures in the spine.
- A quickly worsening fracture that risks resulting in a hunchback posture (kyphosis).
- Intense hunchback posture that interferes with lung functioning.
- In instances of another fracture occurring in the same or neighboring location.
- Painful spinal fractures linked to bone death (osteonecrosis), inability of the fracture to heal, or cystic degeneration.
- Diseases that weaken bones (like multiple myeloma) causing severe pain, and limiting daily activities.
- Bone-weakening diseases that spread (metastases), causing unremitting pain, and heavily restricting day-to-day tasks.
- Spinal fractures resulting from a condition that makes bones extremely fragile and susceptible to break – osteogenesis imperfecta.
- Non-healing of fractures (Pseudoarthroses) following loss of blood supply leading to death of the bone tissue in the spine.
Therefore, if you’re experiencing these types of persistent pain or health issues, your doctor might recommend this type of surgery to help you manage your symptoms and improve the quality of your life.
When a Person Should Avoid Vertebral Augmentation
There are certain situations where specific medical procedures can’t be performed. Here are some reasons why a medical professional might not be able to perform a certain procedure on your back, generally involving a type of surgery known as ’emergent surgical decompression’:
If the break in the backbone extends to the back part of the bone, if the backbone is seriously fractured, or if displaced bone fragments have moved back into the body. These situations can make the surgery unsafe.
If the backbone is unstable, this means it can’t hold and support the body as it should. If there are certain types of bone changes seen in diseases like osteoporosis or cancer (osteoblastic lesions). If other diseases affecting the backbone like osteomyelitis (bone infection) or spondylodiscitis (a disc infection between the bones of the spine) present, surgery may not be safe.
Conditions that affect the body’s ability to stop bleeding (coagulopathy), systemic infections (infections that spread throughout the body), allergies to bone cement (a material used in some surgical procedures), or if the patient is pregnant, may also stop the procedure from being carried out.
Additionally, some certain conditions might make the surgery more challenging but not impossible. These include the collapse of the backbone by more than 75%, damaged pedicles (the small bony bits on the side of the backbone), and facet joints (bony projections joining the backbones together). If a tumor extends into the space within the backbone as well, it poses additional complications for the surgery.
Equipment used for Vertebral Augmentation
In the process of Vertebroplasty (a medical procedure to treat spine fractures, also known as VA), your doctor will require access to specific tools and technology. These include:
* Local anesthesia: a type of medication used to numb a small area of your body where the procedure occurs; this means you stay awake but don’t feel pain.
* General anesthesia: a type of medication that renders you completely unconscious; you feel no pain and have no memory of the procedure when you wake.
* Peripheral intravenous (IV) access: This means a needle will be placed in a vein (usually in your arm), allowing fluids or medication to be given directly into your bloodstream.
* Provision for IV fluids: These are liquids given through the IV to keep you hydrated or deliver medications.
* Patient monitoring units: Devices used to continuously monitor your heart rate, blood pressure, and other vital signs during the procedure.
* Fluoroscopy: This is a type of X-ray that shows real-time images on a monitor; it’s like watching a live movie of the inside of your body.
* Trochar: This is a sharp, pointed instrument used for accessing the fractured vertebra.
* A balloon tamp: A device inflated inside the vertebra to create a space for the cement to be injected.
* Bone cement delivery system: The instrument used to inject the bone cement into the fractured vertebra.
* Bone cement: The currently approved types in the US include polymethylmethacrylate (PMMA) and a type of bioactive calcium phosphate micro-glass cement. The latter is a mixture of special methacrylates (33%) and bioactive glass-ceramic (67%) which is stronger than the PMMA and less prone to producing high heat reactions.
Who is needed to perform Vertebral Augmentation?
Undergoing a procedure called vertebral augmentation (VA) requires the expertise of a highly qualified medical professional, like an orthopedic doctor or a neurosurgeon. These doctors have specialized training through a recognized residency and fellowship program. They are qualified to assess a patient’s health, correctly read and interpret body scans like X-Rays or MRIs, successfully carry out the procedure, and expertly handle the imaging systems.
These specialists are also well-versed in the protocols of radiation safety, which is crucial for the types of imaging used in the procedure. They are additionally well-equipped to handle any complications that might occur during this procedure.
Besides the main doctor performing the procedure, there are other members of the healthcare team involved. This includes an anesthesiologist, who’s responsible for ensuring you are comfortably asleep during the procedure; a radiologic technologist, who manages the imaging equipment; and a nurse who assists the whole team and takes care of your needs.
Preparing for Vertebral Augmentation
For a specific medical procedure, certain requirements need to be met to ensure the best outcome:
- Doctors and support staff should have the right training.
- A high-quality X-ray machine should be used, which is capable of producing clear, detailed images.
- A system should be in place to record and store these images for future reference.
- Equipment should be available to closely monitor the patient’s health during the procedure.
- CT and MRI machines, which help create detailed pictures of the inside of the body, should be easily accessible.
- And finally, the facility should be prepared for emergency assistance and spinal decompression. The latter is a procedure used to relieve pressure on the spinal cord or spinal nerves.
How is Vertebral Augmentation performed
Kyphoplasty and vertebroplasty are two primary methods used to treat vertebral compression fractures (a spinal bone fracture that usually results from osteoporosis). These methods have received approval from Medicare and the Food and Drug Administration (FDA) in the US because they are considered efficient treatment measures.
Among the two, kyphoplasty is seen as the more effective solution. It is efficient in restoring height to spinal bones and reducing the risk of cement leaks. Cement leaks can occur when the substance used to stabilize the spine seeps out. However, thanks to a device known as an inflatable bone tamp, this risk is lowered in kyphoplasty. Because of this and other advantages, kyphoplasty is often preferred over vertebroplasty, even though it is more expensive.
Now, let’s look at the different techniques used for these procedures:
1. Percutaneous Vertebroplasty: In this procedure, medical imaging, or fluoroscopy, is used to guide a needle-like instrument to inject a substance called bone cement into the damaged spinal bone. This cement helps stabilize the fracture and reduce pain.
2. Percutaneous Kyphoplasty: This technique also focuses on fracture reduction, spinal height restoration, and reducing spinal curvature issues. As in the vertebroplasty, a cavity is created, but under low pressure, reducing the risk of leakage. In this procedure, a balloon or bone tamp is inserted and inflated to establish a cavity. Cement is then slowly injected into this space.
3. Radiofrequency Kyphoplasty: Here, an osteotome (a surgical instrument) creates multiple channels within the spinal bone. The radiofrequency accelerates the injection and quickens the process.
4. SpineJack System: This system aids in the restoration of the compressed spinal height followed by kyphoplasty and the injection of bone cement.
5. OsseoFix System: This involves an expandable titanium mesh cage that is slowly expanded and implanted. Then, cement is injected into the cage.
6. KIVA System: In this system, a polymer-based flexible implant is used to restore spinal height and hold the cement in place.
7. Vertebral Body Stenting: This involves inserting a balloon-expandable metal stent into the spinal bone. This expands to restore height, and then cement is injected to create a stent-reinforced cement implant within the treated spinal body.
When a vertebroplasty is scheduled, it’s important to ensure there’s no pain in the sacroiliac and facet joints (the joints connecting the spine to the pelvis and the small joints between the vertebrae in the spine, respectively). Also, check for multiple compression fractures, where the severity can be determined by examining various aspects through specific imaging techniques. This procedure needs extreme accuracy, as it involves passing through sensitive areas in the spine.
Possible Complications of Vertebral Augmentation
A large study of 1932 patients indicated that about 8.6% of people experienced complications after their treatment. Minor complications occurred in 2.7% of cases, major complications in 4.9%, and 2.1% of patients unfortunately passed away. Those who were deemed to be in a high-risk group by the American Society of Anesthesiologists, had high creatinine levels, high white blood cell counts, or low levels of albumin in their blood were more likely to experience major complications.
In a separate analysis involving 1098 patients who went through percutaneous vertebroplasty (PVP), a kind of spine surgery, only 1.5% experienced complications related to the procedure. Serious adverse events, like a new bone fracture with an infection, or respiratory arrest during sedation, were extremely rare.
Various complications can arise during or after vertebroplasty, such as:
* Vasovagal reactions (sudden low heart rate and blood pressure)
* Spinal anesthesia
* Postprocedural pain
* Thermal damage to nearby tissues
* Rib fracture
* Pneumothorax (collapsed lung)
* Leakage of bone cement used in the procedure
* Implantation syndrome
* Pulmonary cement embolism
* Cerebral fat embolism
* Infection
* Incident and adjacent vertebral fractures
* Bone necrosis
Pain after the surgery might result from pressure or lack of blood flow locally. Usually, it goes away in a few hours. If it lasts more than two hours, further examination might be needed to look for potential fractures, cement leakage, embolism, infection or other complications.
Further complications can stem from infections, including a type of bone infection called spondylitis, which might become worse after surgery.
For those at high risk of infection, the use of tobramycin mixed with the cement applied during surgery could be considered.
Leakage of cement is another common complication after vertebroplasty. This is frequently seen in the upper part of the spine and could be caused by several factors. These include high-grade fractures of the vertebra, cortical disruption, applying cement before it reaches optimal viscosity, and many other factors. Identifying and controlling these risk factors could help to prevent such leakage and the complications that follow.
The odds of getting a new bone fracture after surgery are approximately 15%. Having a previous fracture increases this risk. The patient’s body shape and other factors might also contribute to the risk. Research suggests, however, that fracture risk does not increase after vertebroplasty.
Overall, being aware of these potential complications, understanding the patients’ health conditions, and strategies for managing the risks are key to ensuring the best patient care and outcome.
What Else Should I Know About Vertebral Augmentation?
There are varying opinions on the effectiveness of vertebroplasty, a procedure involving injecting bone cement into a fractured vertebra, in reducing pain and improving functional outcomes. In two different medical trials, one called INVEST and another by Buchbinder et al, it was found that vertebroplasty didn’t significantly improve pain compared to a placebo treatment – a fake treatment that’s made to seem like the real one. But there were various limitations to these studies such as fewer participants enrolling than expected, inclusion of old fracture cases, lack of clear imaging technologies, and more.
In 2016, the VAPOUR trial found that the vertebroplasty procedure was effective for patients suffering from severe pain due to fresh vertebral compression fractures, fractures caused by the vertebra becoming compressed due to a collapse. Certain new anaesthetic techniques and equipment were introduced in this trial, which showed promising results in reducing pain. However, it enrolled mostly patients from one site which limits the application of findings.
Another trial in 2018, VERTOS IV found that vertebroplasty was effective in reducing pain after 12 months compared to the placebo group. Notably, patients weren’t requiring heavy-duty pain killers even when they reported moderate to high amounts of pain. Similarly, the more recent VOPE trial found lower pain scores in the vertebroplasty group at the end of 3 months.
Even though these studies do show some benefits of vertebroplasty, it’s critical to consider the different factors in each trial such as the age of the fractures and the amount of cement used. Currently, the evidence suggests vertebroplasty might not be more effective than placebo treatments.
However, other larger scale studies have shown that vertebroplasty and a similar procedure called kyphoplasty, involving creating space in the vertebra before injecting cement, seem to provide survival benefits over not doing any surgery. For instance, patients who had vertebroplasty or kyphoplasty had higher 3-year survival rates in one study using the US Medicare dataset. Similarly, in a German dataset, those who had vertebroplasty were less likely to die within 5 years compared to those managed without surgery.
This suggests that while the effectiveness of pain reduction might be unclear, there could be potential survival benefits with these procedures. Therefore, more research is warranted to understand these benefits and the factors involved.
