Spinal fusion | |
---|---|
Other names | Spondylosyndesis |
Specialty | Orthopedics, Neurology |
ICD-10-PCS | M43.26 |
ICD-9-CM | 81.0 |
MeSH | D013123 |
MedlinePlus | 002968 |
Spinal fusion, also called spondylodesis or spondylosyndesis, is a surgery performed by orthopaedic surgeons or neurosurgeons that joins two or more vertebrae. [1] This procedure can be performed at any level in the spine (cervical, thoracic, lumbar, or sacral) 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 (autograft), donor (allograft), or artificial bone substitutes—to help the bones heal together. [2] Additional hardware (screws, plates, or cages) 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 (cartilage between two vertebrae) wears out (degenerative disc disease). [3] It is also used as a backup procedure for total disc replacement surgery (intervertebral disc arthroplasty), in case patient anatomy prevents replacement of the disc. Other common pathological conditions that are treated by spinal fusion include spinal stenosis, spondylolisthesis, spondylosis, spinal fractures, scoliosis, and kyphosis. [3]
Like any surgery, complications may include infection, blood loss, and nerve damage. [4] 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. [2]
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. [4] The greatest benefit appears to be in spondylolisthesis, while evidence is weaker for spinal stenosis. [5]
The most common cause of pressure on the spinal cord/nerves is degenerative disc disease. [6] Other common causes include disc herniation, spinal stenosis, trauma, and spinal tumors. [4] Spinal stenosis results from bony growths (osteophytes) or thickened ligaments that cause narrowing of the spinal canal over time. [4] This causes leg pain with increased activity, a condition called neurogenic claudication. [4] Pressure on the nerves as they exit the spinal cord (radiculopathy) causes pain in the area where the nerves originated (leg for lumbar pathology, arm for cervical pathology). [4] In severe cases, this pressure can cause neurologic deficits, like numbness, tingling, bowel/bladder dysfunction, and paralysis. [4]
Lumbar and cervical spinal fusions are more commonly performed than thoracic fusions. [6] Degeneration happens more frequently at these levels due to increased motion and stress. [6] The thoracic spine is more immobile, so most fusions are performed due to trauma or deformities like scoliosis, kyphosis, and lordosis. [4]
Conditions where spinal fusion may be considered include the following:
Bone morphogenetic protein (rhBMP) should not be routinely used in any type of anterior cervical spine fusion, such as with anterior cervical discectomy and fusion. [7] 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. [7]
According to a report by the Agency for Healthcare Research and Quality (AHRQ), approximately 488,000 spinal fusions were performed during U.S. hospital stays in 2011 (a rate of 15.7 stays per 10,000 population), which accounted for 3.1% of all operating room procedures. [8] This was a 70 percent growth in procedures from 2001. [9] 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. [6]
A 2008 analysis of spinal fusions in the United States reported the following characteristics:
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 people with 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. [10]
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 (improvement in pain or function) of performing fusion surgery in comparison to intensive rehabilitation including cognitive-behavioral treatment. [11] Similarly, researchers in Washington State[ where? ] 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. [12]
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. [4] After the spine is decompressed, bone graft or artificial bone substitute is packed between the vertebrae to help them heal together. [2] In general, fusions are done either on the anterior (stomach), posterior (back), or both sides of the spine. [4] Today, most fusions are supplemented with hardware (screws, plates, rods) because they have been shown to have higher union rates than non-instrumented fusions. [4] Minimally invasive techniques are also becoming more popular. [13] 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. [13] The following list gives examples of common types of fusion techniques performed at each level of the spine:
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 (BMI), other medical problems, poor nutrition and nerve symptoms (numbness, weakness, bowel/bladder issues) before surgery. [4] Complications also depend on the type/extent of spinal fusion surgery performed. There are three main time periods where complications typically occur:
Recovery following spinal fusion is extremely variable, depending on individual surgeon's preference and the type of procedure performed. [22] The average length of hospital stay for spinal fusions is 3.7 days. [6] Some patients can go home the same day if they undergo a simple cervical spinal fusion at an outpatient surgery center. [23] Minimally invasive surgeries are also significantly reducing the amount of time spent in the hospital. [23] Recovery typically involves both restriction of certain activities and rehabilitation training. [24] [25] 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. [24]
According to a report by the Agency for Healthcare Research and Quality (AHRQ), approximately 488,000 spinal fusions were performed during U.S. hospital stays in 2011, a rate of 15.7 stays per 10,000 population, which accounted for 3.1% of all operating room procedures. [8]
In 2019, the news channel WTOL-TV broadcast an investigation, "Surgical implants raising contamination concerns", uncovering a 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 underreported given the long time frame (0–7 years) and reportedly lack follow up data on the patients undergoing spine surgery. A petition was filed by the lead investigator, Aakash Agarwal, to rectify this global public health hazard of implanting contaminated spinal devices in patients. [26] [27] [28] [29] [30]
The lumbar vertebrae are, in human anatomy, the five vertebrae between the rib cage and the pelvis. They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse process and by the absence of facets on the sides of the body. They are designated L1 to L5, starting at the top. The lumbar vertebrae help support the weight of the body, and permit movement.
Lumbar spinal stenosis (LSS) is a medical condition in which the spinal canal narrows and compresses the nerves and blood vessels at the level of the lumbar vertebrae. Spinal stenosis may also affect the cervical or thoracic region, in which case it is known as cervical spinal stenosis or thoracic spinal stenosis. Lumbar spinal stenosis can cause pain in the low back or buttocks, abnormal sensations, and the absence of sensation (numbness) in the legs, thighs, feet, or buttocks, or loss of bladder and bowel control.
A laminectomy is a surgical procedure that removes a portion of a vertebra called the lamina, which is the roof of the spinal canal. It is a major spine operation with residual scar tissue and may result in postlaminectomy syndrome. Depending on the problem, more conservative treatments may be viable.
Spondylosis is the degeneration of the vertebral column from any cause. In the more narrow sense it refers to spinal osteoarthritis, the age-related degeneration of the spinal column, which is the most common cause of spondylosis. The degenerative process in osteoarthritis chiefly affects the vertebral bodies, the neural foramina and the facet joints. If severe, it may cause pressure on the spinal cord or nerve roots with subsequent sensory or motor disturbances, such as pain, paresthesia, imbalance, and muscle weakness in the limbs.
Degenerative disc disease (DDD) is a medical condition typically brought on by the normal aging process in which there are anatomic changes and possibly a loss of function of one or more intervertebral discs of the spine. DDD can take place with or without symptoms, but is typically identified once symptoms arise. The root cause is thought to be loss of soluble proteins within the fluid contained in the disc with resultant reduction of the oncotic pressure, which in turn causes loss of fluid volume. Normal downward forces cause the affected disc to lose height, and the distance between vertebrae is reduced. The anulus fibrosus, the tough outer layers of a disc, also weakens. This loss of height causes laxity of the longitudinal ligaments, which may allow anterior, posterior, or lateral shifting of the vertebral bodies, causing facet joint malalignment and arthritis; scoliosis; cervical hyperlordosis; thoracic hyperkyphosis; lumbar hyperlordosis; narrowing of the space available for the spinal tract within the vertebra ; or narrowing of the space through which a spinal nerve exits with resultant inflammation and impingement of a spinal nerve, causing a radiculopathy.
Ralph Bingham Cloward was an American neurosurgeon, best known for his innovations in spinal neurosurgery. Cloward is known for the development of the Posterior Lumbar Interbody Fusion and Anterior Cervical Discectomy and Fusion. Cloward moved from Chicago to Hawaii in 1938, becoming the state's lone neurosurgeon. He is well known for his work treating victims of brain injuries after the Pearl Harbour attack in 1941.
Failed back syndrome or post-laminectomy syndrome is a condition characterized by chronic pain following back surgeries. Many factors can contribute to the onset or development of FBS, including residual or recurrent spinal disc herniation, persistent post-operative pressure on a spinal nerve, altered joint mobility, joint hypermobility with instability, scar tissue (fibrosis), depression, anxiety, sleeplessness, spinal muscular deconditioning and even Cutibacterium acnes infection. An individual may be predisposed to the development of FBS due to systemic disorders such as diabetes, autoimmune disease and peripheral blood vessels (vascular) disease.
The intervertebral foramen is an opening between two pedicles of adjacent vertebra in the articulated spine. Each intervertebral foramen gives passage to a spinal nerve and spinal blood vessels, and lodges a posterior (dorsal) root ganglion. Cervical, thoracic, and lumbar vertebrae all have intervertebral foramina.
Anterior cervical discectomy and fusion (ACDF) is a surgical procedure to treat nerve root or spinal cord compression by decompressing the spinal cord and nerve roots of the cervical spine with a discectomy, followed by inter-vertebral fusion to stabilize the corresponding vertebrae. This procedure is used when other non-surgical treatments have failed.
Cervical spinal stenosis is a bone disease involving the narrowing of the spinal canal at the level of the neck. It is frequently due to chronic degeneration, but may also be congenital. Treatment is frequently surgical.
A laminotomy is an orthopaedic neurosurgical procedure that removes part of the lamina of a vertebral arch in order to relieve pressure in the vertebral canal. A laminotomy is less invasive than conventional vertebral column surgery techniques, such as laminectomy because it leaves more ligaments and muscles attached to the spinous process intact and it requires removing less bone from the vertebra. As a result, laminotomies typically have a faster recovery time and result in fewer postoperative complications. Nevertheless, possible risks can occur during or after the procedure like infection, hematomas, and dural tears. Laminotomies are commonly performed as treatment for lumbar spinal stenosis and herniated disks. MRI and CT scans are often used pre- and post surgery to determine if the procedure was successful.
Artificial disc replacement (ADR), or total disc replacement (TDR), is a type of arthroplasty. It is a surgical procedure in which degenerated intervertebral discs in the spinal column are replaced with artificial disc implants in the lumbar (lower) or cervical (upper) spine. The procedure is used to treat chronic, severe low back pain and cervical pain resulting from degenerative disc disease. Disc replacement is also an alternative intervention for symptomatic disc herniation with associated arm and hand, or leg symptoms.
Laminoplasty is an orthopaedic/neurosurgical surgical procedure for treating spinal stenosis by relieving pressure on the spinal cord. The main purpose of this procedure is to provide relief to patients who may have symptoms of numbness, pain, or weakness in arm movement. The procedure involves cutting the lamina on both sides of the affected vertebrae and then "swinging" the freed flap of bone open thus relieving the pressure on the spinal cord. The spinous process may be removed to allow the lamina bone flap to be swung open. The bone flap is then propped open using small wedges or pieces of bone such that the enlarged spinal canal will remain in place.
Spinal decompression is the relief of pressure on the spinal cord or on one or more compressed nerve roots passing through or exiting the spinal column. Decompression of the spinal neural elements is a key component in treating spinal radiculopathy, myelopathy and claudication.
An interbody fusion cage is a prosthesis used in spinal fusion procedures to maintain foraminal height and decompression. They are cylindrical or square-shaped devices, and usually threaded. There are several varieties: the Harms cage, Ray cage, Pyramesh cage, InterFix cage, and lordotic LT cage, all of which are made from titanium; the Brantigan cage, made from carbon fibre; and the Cortical Bone Dowel, which is cut from allograft femur. The cages can be packed with autologous bone material in order to promote arthrodesis. Such implants are inserted when the space between the spinal discs is distracted, such that the implant, when threaded, is compressed like a screw. Unthreaded implants, such as the Harms and Pyramesh cages have teeth along both surfaces that bite into the end plates.
Spinal stenosis is an abnormal narrowing of the spinal canal or neural foramen that results in pressure on the spinal cord or nerve roots. Symptoms may include pain, numbness, or weakness in the arms or legs. Symptoms are typically gradual in onset and improve with leaning forward. Severe symptoms may include loss of bladder control, loss of bowel control, or sexual dysfunction.
Minimally invasive spine surgery, also known as MISS, has no specific meaning or definition. It implies a lack of severe surgical invasion. The older style of open-spine surgery for a relatively small disc problem used to require a 5-6 inch incision and a month in the hospital. MISS techniques utilize more modern technology, advanced imaging techniques and special medical equipment to reduce tissue trauma, bleeding, radiation exposure, infection risk, and decreased hospital stays by minimizing the size of the incision. Modern endoscopic procedures can be done through a 2 to 5 mm skin opening. By contrast, procedures done with a microscope require skin openings of approximately one inch, or more.
The ventral slot technique is a procedure that allows the surgeon to reach and decompress the spinal cord and associated nerve roots from a ventral route in veterinary medicine. There are also alternative ways to open the spinal canal from dorsal by performing a hemilaminectomy, but this often gives only limited access. Even when the main pathological changes evolve from the midline, it is necessary to choose a ventral approach.
Each vertebra is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal segment and the particular species.
NuVasive, Inc. is a medical devices company based in San Diego, California. Founded in 1997, it primarily develops medical devices and procedures for minimally invasive spine surgery.