Spinal fusion


Spinal fusion, also called spondylodesis or spondylosyndesis, is a neurosurgical or orthopedic surgical technique that joins two or more vertebrae. This procedure can be performed at any level in the spine and prevents any movement between the fused vertebrae. There are many types of spinal fusion and each technique involves using bone grafting—either from the patient, donor, or artificial bone substitutes—to help the bones heal together. Additional hardware is often used to hold the bones in place while the graft fuses the two vertebrae together. The placement of hardware can be guided by fluoroscopy, navigation systems, or robotics.
Spinal fusion is most commonly performed to relieve the pain and pressure from mechanical pain of the vertebrae or on the spinal cord that results when a disc wears out. Other common pathological conditions that are treated by spinal fusion include spinal stenosis, spondylolisthesis, spondylosis, spinal fractures, scoliosis, and kyphosis.
Like any surgery, complications may include infection, blood loss, and nerve damage. Fusion also changes the normal motion of the spine and results in more stress on the vertebrae above and below the fused segments. As a result, long-term complications include degeneration at these adjacent spine segments.

Medical uses

Spinal fusion can be used to treat a variety of conditions affecting any level of the spine—lumbar, cervical and thoracic. In general, spinal fusion is performed to decompress and stabilize the spine. The greatest benefit appears to be in spondylolisthesis, while evidence is less good for spinal stenosis.
The most common cause of pressure on the spinal cord/nerves is degenerative disc disease. Other common causes include disc herniation, spinal stenosis, trauma, and spinal tumors. Spinal stenosis results from bony growths or thickened ligaments that cause narrowing of the spinal canal over time. This causes leg pain with increased activity, a condition called neurogenic claudication. Pressure on the nerves as they exit the spinal cord causes pain in the area where the nerves originated. In severe cases, this pressure can cause neurologic deficits, like numbness, tingling, bowel/bladder dysfunction, and paralysis.
Lumbar and cervical spinal fusions are more commonly performed than thoracic fusions. Degeneration happens more frequently at these levels due to increased motion and stress. The thoracic spine is more immobile, so most fusions are performed due to trauma or deformities like scoliosis, kyphosis, and lordosis.
Conditions where spinal fusion may be considered include the following:
should not be routinely used in any type of anterior cervical spine fusion, such as with anterior cervical discectomy and fusion. There are reports of this therapy causing soft tissue swelling, which in turn can cause life-threatening complications due to difficulty swallowing and pressure on the respiratory tract.

Epidemiology

According to a report by the Agency for Healthcare Research and Quality, approximately 488,000 spinal fusions were performed during U.S. hospital stays in 2011, which accounted for 3.1% of all operating room procedures. This was a 70 percent growth in procedures from 2001. Lumbar fusions are the most common type of fusion performed ~ 210,000 per year. 24,000 thoracic fusions and 157,000 cervical fusions are performed each year.
A 2008 analysis of spinal fusions in the United States reported the following characteristics:
Costs associated with spinal fusion vary depending on the medical institution, insurance, type of surgery and the overall health of the patient. Total costs typically include labs, medications, room & board, medical supplies, recovery room, operating room services, physical therapy, imaging, and hospital charges. In the health care system of the United States, the average total hospital costs for spinal fusions increased from $24,676 in 1998 to $81,960 in 2008. The average total costs of common fusion procedures are listed below:
Costs also depend on operative time, complications, and need for revision surgery due to malaligned hardware. Average cost of infection is $15,817 to $38,701. Average cost of revision surgery is $26,593 to $86,673.

Effectiveness

Although spinal fusion surgery is widely performed, there is limited evidence for its effectiveness for several common medical conditions. For example, in a randomized controlled trial of sufferers of spinal stenosis, after 2 and 5 years there was no significant clinical benefits of lumbar fusion in combination with decompression surgery, in comparison to decompression surgery alone. This Swedish study, including 247 patients enrolled from 2006 to 2012, further found increased medical costs for those who received the fusion surgery, as a result of increased surgery time, hospital stay duration, and cost of the implant. Additionally, a 2009 systematic review on surgery for lower back pain found that for nonradicular low back pain with degenerative disk disease, there was no benefit in health outcomes of performing fusion surgery in comparison to intensive rehabilitation including cognitive-behavioral treatment. Similarly, researchers in Washington State viewed lumbar fusion surgery to have questionable medical benefit, increased costs, and increased risks, in comparison to intensive pain programs for chronic low back pain with degenerative disk disease.

Technique

There are many types of spinal fusion techniques. Each technique varies depending on the level of the spine and the location of the compressed spinal cord/nerves. After the spine is decompressed, bone graft or artificial bone substitute is packed between the vertebrae to help them heal together. In general, fusions are done either on the anterior, posterior, or both sides of the spine. Today, most fusions are supplemented with hardware because they have been shown to have higher union rates than non-instrumented fusions. Minimally invasive techniques are also becoming more popular. These techniques use advanced image guidance systems to insert rods/screws into the spine through smaller incisions, allowing for less muscle damage, blood loss, infections, pain, and length of stay in the hospital. The following list gives examples of common types of fusion techniques performed at each level of the spine:

Cervical spine

Risks

Spinal fusion is a high risk surgery and complications can be serious, including death. In general, there is a higher risk of complications in older people with elevated body mass index, other medical problems, poor nutrition and nerve symptoms before surgery. Complications also depend on the type/extent of spinal fusion surgery performed. There are three main time periods where complications typically occur:

During surgery

Recovery following spinal fusion is extremely variable, depending on individual surgeon's preference and the type of procedure performed. The average length of hospital stay for spinal fusions is 3.7 days. Some patients can go home the same day if they undergo a simple cervical spinal fusion at an outpatient surgery center. Minimally invasive surgeries are also significantly reducing the amount of time spent in the hospital. Recovery typically involves both restriction of certain activities and rehabilitation training. Restrictions following surgery largely depend on surgeon preference. A typical timeline for common restrictions after a lumbar fusion surgery are listed below:
Rehabilitation after spinal fusion is not mandatory. There is some evidence that it improves functional status and low back pain so some surgeons may recommend it.

Usage

According to a report by the Agency for Healthcare Research and Quality, approximately 488,000 spinal fusions were performed during U.S. hospital stays in 2011, which accounted for 3.1% of all operating room procedures.

Public health hazard

In 2019, WTOL released an investigation titled , uncovering dossier of scientific evidences that current methods of processing and handling spinal implants are extremely unhygienic and lacks quality control. This lack of quality control is exposing patients to high risk of infection, which themselves are under-reported given the long time frame and hence lack of follow up data on the patients undergoing spine surgery. A has been filed by the led investigator of this discovery, , to rectify this global public health hazard of implanting contaminated spinal devices in patients.