What is Chance Fractures?
A Chance fracture is a serious type of spine injury that usually happens at the junction between the thoracic (upper) and lumbar (lower) spine. It’s a kind of horizontal fracture that runs from the back to the front, through the bony extensions on each side of a vertebra, and the vertebral body. These fractures can be missed during a medical exam because patients often don’t show any nerve-related symptoms. But, up to 50% of these cases can have associated internal abdominal injuries. It’s vital to identify this injury early because a late diagnosis can significantly worsen the patient’s health outcome.
What Causes Chance Fractures?
A Chance fracture is a type of spinal injury caused by a sudden forward bending movement. This type of fracture was first identified by G.Q. Chance, a radiologist from Manchester, UK, in 1948. He described it as a “horizontal splitting fracture of the spine.”
People didn’t connect the use of lap seat belts in cars with Chance fractures until the 1960s. This injury, often referred to as a “seat belt fracture,” typically happens when there’s a sudden slowdown in a car crash. This sudden stop forces the spine to bend rapidly over the lap seat belt, causing parts of the spine to pull apart. While car crashes are the most common cause of this kind of injury, Chance fractures can also occur due to falls and violent attacks.
Risk Factors and Frequency for Chance Fractures
In the United States, around 160,000 people suffer from fractures in the thoracolumbar spine every year. The second most frequent location for spinal injuries is the thoracolumbar junction, coming after the neck or cervical spine. In fact, about half of all spinal injuries that are not in the neck area happen at the thoracolumbar junction.
- Chance fractures are commonly seen in children and young adults.
- They occur more often in males than in females.
- A study conducted by Bernstein and team found that the average age of patients was 26 years.
- The patients’ ages ranged from 9 to 54 years.
- The ratio of males to females suffering from Chance fractures was 3 to 1.
Signs and Symptoms of Chance Fractures
A Chance fracture usually happens when a person experiences a sudden stop in a car crash. This sudden stop causes the person’s spine to sharply bend over the lap seatbelt. This injury mainly causes back pain, but without signs of nerve damage. However, symptoms such as weakness, numbness, and loss of bladder control can occur if there’s a bruise or impact to the spinal cord or to the bundle of nerves at the end of the spinal cord. This can happen due to pieces of the broken back bone being pushed into these structures.
One important thing doctors look for during the physical exam is the “seatbelt sign”. This refers to signs of bruising or scraping on the belly showing the path of a seat belt. The presence of this sign may suggest a Chance fracture and possible damage to the organs in the stomach. The “seatbelt sign” can also be seen on a scan as threading in the soft, squishy layer under the skin of the front belly wall.
Because of the possible danger of damage to the bladder and intestines, it’s highly recommended that all patients with belly pain following accident be examined by a surgeon. It’s also crucial that a carefully conducted exam of the nervous system be done. The bladder and rectum should also be checked.
sustained in a motor vehicle collision while wearing a lap belt.
Testing for Chance Fractures
The American College of Radiology suggests getting imaging of the middle and lower spine if you have certain symptoms. These include back ache, signs of spine injury, unusual neurological symptoms, a neck fracture, a distracted injury, alcohol or drug intoxication, or a Glasgow coma score under 15.
For people aged 16 or above who may have middle or lower spine injury, the first and best imaging test is a computed tomography (CT) scan. CT scans are better than normal x-rays to detect fractures and other injuries, like internal injuries in the abdomen. If you’re getting CT scans for other areas like the chest, stomach or pelvis, you won’t need a separate CT scan for your spine because those scans will cover it. It’s important to get certain viewing angles on the CT scan to identify a specific type of spine fracture called a ‘Chance Fracture.’
On a CT scan, a ‘Chance Fracture’ looks like a horizontal break across the back part of a spine bone (vertebra), which may include shrinking of the part of the vertebra closer to your abdomen and bulging of the part of the vertebra closer to your back. It can also show a pulling apart of the small bones and joint areas on the spine.
However, an MRI (Magnetic Resonance Imaging) scan is better than a CT scan for detecting injuries to soft tissues. This include injuries to the ligaments, the spinal cord, the nerve roots at the bottom of the spine, and the spinal discs. If you have symptoms that suggest a spinal cord injury or injury to the ligaments, you should get an MRI.
On an MRI, a ‘Chance Fracture’ looks like a bright white area (indicating swelling) around darker fracture line, a break in the ligaments between the spines, an injury to the disc between the vertebrae, swelling of the spinal cord, and a blood clot in the space outside the spinal cord.
The American College of Radiology recommends normal spinal x-rays as the initial imaging for kids under 16 with possible middle or lower spine injury. But, it also notes that starting with CT or MRI in some cases might be suitable and even necessary. For instance, if a patient under 16 is getting a CT scan for possible abdominal injuries, the doctor will also be able to check the spine with the same CT images.
Treatment Options for Chance Fractures
Chance fractures can be treated either with conservative methods, like using a cast or brace, or with a surgical procedure. If the fracture is only in the bone and the patient has no nervous system issues, the conservative treatment can be a suitable choice. This involves using a cast or a thoracolumbosacral orthosis (a brace that supports the backbone) to immobilize the area and allow the bone to heal over time. However, if the patient has nervous system complications or if the injury involves the ligaments, surgery may be needed.
Many types of surgical procedures can be used to treat Chance fractures, but the most commonly recommended one in medical literature involves using screws to stabilize the spine over a long segment. This procedure might also involve spinal decompression and fusion.
In treating a chance fracture without surgery, the area around the fracture is often stretched using a special table, and then a custom-made cast is applied. The main issue with this treatment is that the cast can be uncomfortable, leading to a lack of patient cooperation. The cast is typically worn for 8-12 weeks, after which X-rays are taken to check for any remaining deformity. Usually, this conservative treatment leads to a high rate of successful outcomes, but patients must still go through serious rehabilitation to regain muscle strength and mobility.
Surgery may be the only option for patients who are overweight or have a larger build because non-surgical methods may not be effective. Thanks to technological advancements, screws can now be inserted into the spine with minimally invasive methods, which have fewer complications compared to traditional open surgery.
What else can Chance Fractures be?
“Exploding” fracture: When the spine is squeezed from top to bottom, the vertebra can break and this often results in a vertical crack in the back part of the spine. A certain type of spine fracture, called a Chance fracture, happens differently. Its crack runs horizontally across the back section of the spine.
“Crushing” fracture: Again, when the spine is squeezed from top to bottom, the vertebra can break. However, in this case, the back part of the spine remains intact. A Chance fracture can be related here as well, but remember it involves a horizontal crack across the back section of the spine.
“Pulling apart” injury: When the spine is pulled in an upward direction, two of the spinal bones can be separated from each other. This is different from a Chance fracture wherein a horizontal fracture runs through the spinal bone and its protruding parts.
“Slipping” injury: When the bones of the spine are pushed in opposite directions, one spinal bone might slip over another. This differs from a Chance fracture because a Chance fracture involves a horizontal crack across the spinal bone and its protruding parts.
What to expect with Chance Fractures
The outlook for adults with a Chance fracture depends on the severity of the spinal curve or ‘kyphosis’ caused by the injury. For those with a curve of less than 15 degrees, a cast or brace can often be successful in treatment, with good to fair results and no damage to the nervous system.
If the curve is more severe, surgery is usually needed to stabilize the fracture. The good news is, over 90% of these cases have good outcomes after one year.
In children too, the degree of spinal curve correlates with the seriousness of the injury.
Unfortunately, future lower back pain can be a significant issue for some people who have had this type of fracture.
Possible Complications When Diagnosed with Chance Fractures
- Continued lower back pain
- Remaining deformity causing hunched back
- Pressure ulcers
Recovery from Chance Fractures
After an operation, it’s crucial for patients to get moving as soon as possible. There are other aspects to consider too, such as the patient’s diet, along with bowel and bladder function. Preventative measures against pressure sores and blood clots in the deep veins need to be initiated as well.
Preventing Chance Fractures
Following the current recommendations from the American Academy of Pediatrics about the use of car seats and modifications for children could help reduce the chances of them getting a type of back injury known as a “Chance fracture.” These guidelines are designed to keep children safe while riding in vehicles.