Spinal fusion, also called spondylodesis or spondylosyndesis, is a neurosurgical or orthopedic surgical technique that joins two or more

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characterist ...

e. This procedure can be performed at any level in the spine (cervical, thoracic, or lumbar) 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. 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 Fluoroscopy () is an imaging technique that uses X-rays to obtain real-time moving images of the interior of an object. In its primary application of medical imaging, a fluoroscope () allows a physician to see the internal structure and functi ...

, navigation systems, or

robotics Robotics is an interdisciplinarity, interdisciplinary branch of computer science and engineering. Robotics involves design, construction, operation, and use of robots. The goal of robotics is to design machines that can help and assist human ...

. 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). 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 Spondylolisthesis is the displacement of one spinal vertebra compared to another. While some medical dictionaries define spondylolisthesis specifically as the forward or anterior displacement of a vertebra over the vertebra inferior to it (or t ...

, spondylosis, spinal fractures,

scoliosis Scoliosis is a condition in which a person's spine has a sideways curve. The curve is usually "S"- or "C"-shaped over three dimensions. In some, the degree of curve is stable, while in others, it increases over time. Mild scoliosis does not t ...

, 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

, 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 ( osteophytes) 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 (

radiculopathy Radiculopathy, also commonly referred to as pinched nerve, refers to a set of conditions in which one or more nerves are affected and do not work properly (a neuropathy). Radiculopathy can result in pain ( radicular pain), weakness, altered sensat ...

) causes pain in the area where the nerves originated (leg for lumbar pathology, arm for cervical pathology). 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

, kyphosis, and lordosis. Conditions where spinal fusion may be considered include the following: * Degenerative disc disease *

Spinal disc herniation Spinal disc herniation is an injury to the cushioning and connective tissue between vertebrae, usually caused by excessive strain or trauma to the spine. It may result in back pain, pain or sensation in different parts of the body, and physica ...

* Discogenic pain * Spinal

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

* Vertebral fracture *

Scoliosis Scoliosis is a condition in which a person's spine has a sideways curve. The curve is usually "S"- or "C"-shaped over three dimensions. In some, the degree of curve is stable, while in others, it increases over time. Mild scoliosis does not t ...

* Kyphosis (e. g.,

Scheuermann's disease Scheuermann's disease is a self-limiting skeletal disorder of childhood. Scheuermann's disease describes a condition where the vertebrae grow unevenly with respect to the sagittal plane; that is, the posterior angle is often greater than the an ...

) * Lordosis *

Spondylolisthesis Spondylolisthesis is the displacement of one spinal vertebra compared to another. While some medical dictionaries define spondylolisthesis specifically as the forward or anterior displacement of a vertebra over the vertebra inferior to it (or t ...

* Spondylosis *

Posterior rami syndrome Posterior ramus syndrome, also referred to as thoracolumbar junction syndrome, Maigne syndrome and dorsal ramus syndrome is caused by the unexplained activation of the primary division of a posterior ramus of a spinal nerve ( dorsal ramus of spinal ...

* Other degenerative spinal conditions * Any condition that causes instability of the spine

Contraindications

Bone morphogenetic protein Bone morphogenetic proteins (BMPs) are a group of growth factors also known as cytokines and as metabologens. Originally discovered by their ability to induce the formation of bone and cartilage, BMPs are now considered to constitute a group of ...

(rhBMP) should not be routinely used in any type of anterior cervical spine fusion, such as with anterior cervical discectomy and fusion., which cites * * There are reports of this therapy causing

soft tissue Soft tissue is all the tissue in the body that is not hardened by the processes of ossification or calcification such as bones and teeth. Soft tissue connects, surrounds or supports internal organs and bones, and includes muscle, tendons, liga ...

swelling, which in turn can cause life-threatening complications due to difficulty swallowing and pressure on the

respiratory tract The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa. Air is breathed in through the nose to ...

Epidemiology

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. 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: * Average age for someone undergoing a spinal fusion was 54.2 years – 53.3 years for primary cervical fusions, 42.7 years for primary thoracic fusions, and 56.3 years for primary lumbar fusions * 45.5% of all spinal fusions were on men * 83.8% were white, 7.5% black, 5.1% Hispanic, 1.6% Asian or Pacific Islander, 0.4% Native American * Average length of hospital stay was 3.7 days – 2.7 days for primary cervical fusion, 8.5 days for primary thoracic fusion, and 3.9 days for primary lumbar fusion * In-hospital mortality was 0.25%

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 A randomized controlled trial (or randomized control trial; RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical ...

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. Additionally, a 2009

systematic review A systematic review is a scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from published studies on t ...

on surgery for

lower back pain Low back pain (LBP) or wiktionary:lumbago#Etymology, lumbago is a common musculoskeletal disorders, disorder involving the muscles, nerves, and bones of the back, in between the lower edge of the ribs and the lower fold of the buttocks. Pain can ...

found that for nonradicular

low back pain Low back pain (LBP) or lumbago is a common disorder involving the muscles, nerves, and bones of the back, in between the lower edge of the ribs and the lower fold of the buttocks. Pain can vary from a dull constant ache to a sudden sharp fee ...

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. 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

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 (stomach), posterior (back), or both sides of the spine. Today, most fusions are supplemented with hardware (screws, plates, rods) 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: ACDF surgery english

Cervical spine

* Anterior cervical discectomy and fusion (ACDF) * Anterior cervical

corpectomy A corpectomy or vertebrectomy is a surgical procedure that involves removing all or part of the vertebral body (Latin: ''corpus vertebrae'', hence the name corpectomy), usually as a way to decompress the spinal cord and nerves. Corpectomy is often ...

and fusion * Posterior cervical decompression and fusion

Thoracic spine

* Anterior decompression and fusion * Posterior instrumentation and fusion – many different types of hardware can be used to help fuse the thoracic spine including sublaminar wiring, pedicle and transverse process hooks, pedicle screw-rod systems, vertebral body plate systems.

Lumbar spine

* Posterolateral fusion is a bone graft between the

transverse process The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

es in the back of the spine. These vertebrae are then fixed in place with screws or wire through the pedicles of each vertebra, attaching to a metal rod on each side of the vertebrae. * Interbody Fusion is a graft where the entire intervertebral disc between vertebrae is removed and a bone graft is placed in the space between the

. A plastic or titanium device may be placed between the vertebra to maintain spine alignment and disc height. The types of interbody fusion are: *# Anterior lumbar interbody fusion (ALIF) – the disc is accessed from an anterior abdominal incision *# Posterior lumbar interbody fusion (PLIF) – the disc is accessed from a posterior incision *# Transforaminal lumbar interbody fusion (TLIF) – the disc is accessed from a posterior incision on one side of the spine *# Transpsoas interbody fusion (DLIF or XLIF) – the disc is accessed from an incision through the psoas muscle on one side of the spine *# Oblique lateral lumbar interbody fusion (OLLIF) – the disc is accessed from an incision through the psoas muscle obliquely Blausen 0446 HarringtonRods

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 (BMI), other medical problems, poor nutrition and nerve symptoms (numbness, weakness, bowel/bladder issues) 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

* Patient positioning on operating table * Blood loss * Damage to nerves and surrounding structures during procedure * Insertion of spinal hardware * Harvesting of bone graft (if autograft is used)

Within a few days

* Moderate to severe postoperative pain * Wound infections - risk factors include old age, obesity, diabetes, smoking, prior surgery *

Deep vein thrombosis Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and e ...

(DVT) *

Pulmonary embolism Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathing ...

(PE) *

Urinary retention Urinary retention is an inability to completely empty the bladder. Onset can be sudden or gradual. When of sudden onset, symptoms include an inability to urinate and lower abdominal pain. When of gradual onset, symptoms may include loss of blad ...

Malnutrition Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is "a deficiency, excess, or imbalance of energy, protein and other nutrients" which adversely affects the body's tissues ...

* Neurologic deficit

Weeks to years following surgery

* Infection – sources of bacterial bioburden that infiltrate the wound site are several, but the latest research highlights repeated reprocessing of implants before surgery and exposure of implants (such as pedicle screws) to bacterial contaminants in the "sterile-field" during surgery as major risk factors. * Deformity – loss of height, alignment, and failure of fusion *

Pseudarthrosis Nonunion is permanent failure of healing following a broken bone unless intervention (such as surgery) is performed. A fracture with nonunion generally forms a structural resemblance to a fibrous joint, and is therefore often called a "false joi ...

– nonunion between fused bone segments. Risk factors include tobacco use,

nonsteroidal anti-inflammatory drug Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of ...

use, osteoporosis, revision procedures, decreased immune system. * Adjacent segment disease – degeneration of vertebrae above/below the fused segments due altered biomechanical stresses or patient propensity to develop progressive degenerative change. * Epidural fibrosis – scarring of the tissue that surrounds the spinal cord * Arachnoiditis – inflammation of the thin membrane surrounding the spinal cord, usually caused by infection or contrast dye.

Recovery

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: * Walking – most people are out of bed and walking the day after surgery * Sitting – can begin at 1–6 weeks following surgery * Lifting – it is generally recommended to avoid lifting until 12 weeks * Driving – usually can begin at 3–6 weeks * Return to sedentary work – usually between 3–6 weeks * Return to manual work – between 7–12 weeks 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

Public health hazard

In 2019, WTOL released an investigation title
"Surgical implants raising contamination concerns"
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 (0–7 years) and hence lack of follow up data on the patients undergoing spine surgery.
petition
has been filed by the lead investigator of this discovery
Aakash Agarwal
to rectify this global public health hazard of implanting contaminated spinal devices in patients.

References

External links

* Wheeless, C. R., et al., Eds
Fusion of the Spine.
''Wheeless' Textbook of Orthopaedics''. Division of Orthopedic Surgery. Duke University Medical Center.
Spinal Fusion.
American Academy of Orthopaedic Surgeons. June 2010. Accessed 1 June 2013. * Spinasanta, S
What is Spinal Instrumentation and Spinal Fusion?
SpineUniverse. September 2012. Accessed 1 June 2013.

Encyclopedia of Surgery. Accessed 1 June 2013. {{Operations and other procedures on the musculoskeletal system Neurosurgical procedures Orthopedic surgical procedures