Introduction:
Spinal fusion is a surgical procedure where the vertebrae are permanently joined or fused into one single solid bone with no spaces between them. The vertebrae are the small, interlocking bones of the spine collectively termed a vertebral column. Bone grafts fill the naturally occurring space between the separate vertebrae, which is filled up and sealed when the bone heals.
What Are the Types of Spinal Fusion?
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Arthrodesis.
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Anterior spinal fusion.
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Posterior spinal fusion.
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Vertebral interbody fusion.
When Is Spinal Fusion Recommended?
Spinal fusion surgeries are performed to treat or relieve symptoms of many spinal problems that result in back pain due to routine activity. It is indicated primarily in discogenic pain (caused by degenerative disc changes) and spinal instabilities caused by decompressive surgical procedures. As the procedure removes mobility between vertebrae, it reduces the spine's flexibility. However, it remedies the underlying spinal disorders, thus reducing pain originating from movements. The diseases that necessitate such a procedure are as follows;
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Tumors or growths in the vertebral column or spinal cord.
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Stenosis of the spinal cord or nerve roots of cranial and spinal nerves.
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Disk hernias.
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Degeneration of the intervertebral disks caused by diseases.
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Fracture of the vertebrae that causes instability of the spine.
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Scoliosis or hump-like curve of the vertebral column.
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Kyphosis or an exaggerated, forward rounding of the upper back.
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Weakness of the spine due to disease or senescence.
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Spondylolisthesis is where a vertebra slips onto the vertebra below it, impinging upon the spinal cord or nerves, resulting in excruciating pain.
A spinal fusion procedure may either be done alone or may include a discectomy, which involves the removal of the injured or affected disk. Bone grafts are placed into the now empty disc space created after discectomy to maintain the proper height between the bones. Then, two adjacent vertebrae on either side of the removed disk are bridged or fused across the bone grafts to stabilize the spine.
When performed in the cervical spine along with a discectomy, such a procedure is known as cervical fusion surgery, where in place of removing a vertebra, the discs or bone spurs from the cervical spine present in the neck are removed.
How Does Preoperative Preparation Look Like for Spinal Fusion?
Like any other major surgical procedure, preoperative preparation for spinal fusion surgery requires preoperative laboratory testing to determine the presence of systemic diseases and lifestyle habits that may affect the outcome of the surgery.
The conditions that may affect the short or long-term effects of the procedure are as follows;
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Cigarette smoking may reduce the ability or prolong the time needed to heal postoperatively.
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Consumption of alcoholic beverages.
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Presence of preexisting disease or illnesses such as influenza or herpetic diseases.
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Drug and allergy history of the patient.
The medications that are taken before and after the procedure should thoroughly be discussed with the consulting surgeon, who may provide special instructions in case of blood-thinning medications that could affect blood clotting and wound healing, including anticoagulants and nonsteroidal anti-inflammatory drugs (NSAIDs), such as Aspirin and Ibuprofen.
How Is Spinal Fusion Surgery Conducted?
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Anesthesia: Spinal fusion is performed under general anesthesia. During the procedure, the blood pressure and heart rates are constantly monitored using a pressure cuff and lead on the chest, which allows the surgeon and anesthesiologist to monitor the vital signs during surgery which may take several hours.
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Bone Grafting: A bone graft is prepared to fuse the two vertebrae, which may be derived from the patient's pelvic bone. Synthetic bone grafts or allografts may be obtained from a bone bank or a consenting donor.
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Surgery: The surgeon makes an incision for placement of the bone, depending on the site of bone fusion. In case of a cervical fusion, a small incision is made in the horizontal fold of the front of your neck to expose the cervical spine. Then, the bone graft is placed between the affected vertebrae to fuse them. The graft material may sometimes be inserted between the vertebrae in specially fabricated cages or over the back part of the spine. Once in place, the bone graft is stabilized in position using plates, screws, and rods that prevent the spine from undesired movements by internal fixation. The additional stability provided by the plates, screws, and rods helps the spine heal faster and with a higher success rate.
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Pain Management: It is done with medication with instructions about the new ways to move since the flexibility may be limited. One might also need to learn new techniques to walk, sit, and stand safely. A solid food diet for a few days may be avoided unless otherwise advised by the surgeon.
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Postoperative Phase: Post-discharge from the hospital, the patient may need to wear a brace to keep the spine in proper alignment. A rest period will be advised before returning to resume everyday activities until the bone has fused into place. Complete fusing may take up to six weeks or longer with physical rehabilitation to help strengthen the back and learn ways to move safely. Full recovery from spinal fusion takes three to six months, depending upon age, overall health, and physical condition.
What Are the Postoperative Complications of Spinal Fusion?
As with any major surgical procedure, spinal fusion surgery may also carry risks of certain complications, as follows;
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Infection of the surgical site.
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Blood clots in the head and neck or extremities.
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Dissemination of the blood clots to the lungs may be fatal.
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Bleeding and blood loss may lead to death.
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Increased risk of a heart attack during an ongoing surgery.
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Increased risk of strokes.
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Delayed or inadequate wound healing due to systemic diseases such as diabetes.
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Allergic or anaphylactic reactions to medications or anesthetic agents administered.
Certain rare complications may also be seen, enlisted as follows;
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Infection in the treated vertebrae.
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Damage to a spinal or cranial nerve or nerve root leads to weakness, pain, bowel or bladder problems, or neuralgic pain.
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Stress on the bones adjacent to the surgically treated vertebrae due to loss of flexibility and increased stiffness.
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Persistent pain at the donor bone graft site if an autograft is used.
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Allergic reaction caused by synthetic bone grafts.
The most severe complications, as mentioned above, are blood clots, disseminated clots to other sites, and an infection of the surgical site, which have a high chance of occurring during the first few weeks of the postoperative recovery phase.
Removal of the hardware is necessary in case of postoperative pain or discomfort, and emergency help should be sought if one experiences any of the symptoms of a blood clot enlisted as follows;
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Sudden swelling in the calf, ankle, or foot.
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Redness or tenderness is seen either above or below the knee.
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Calf pain.
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Groin pain.
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Shortness of breath or difficulty breathing.
A patient should seek emergency help if any of the symptoms of infection are seen, enlisted as follows;
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Redness or swelling at the edges of the surgical site.
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Fluid drainage such as blood or pus from the surgical site.
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Fever, chills, or elevated body temperature over 100 degrees Fahrenheit.
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Shaking and malaise.
What Is Minimally Invasive Spinal Fusion?
With recent advancements in almost all fields of extensive surgeries, minimally invasive spinal fusion surgeries use a smaller incision than traditional surgery, preserving the muscle attachments to the spine. As mentioned earlier, this leads to a faster recovery than conventional surgery and reduced chances for specific problems. A small incision to access the spine is made, and the back muscles are gently pushed away with a unique tool. Two or more vertebrae are then welded together using bone or other artificial materials.
Conclusion
Spinal fusion involves the fusion of a single solid bone with no spaces between them. Then, a bone graft is prepared to merge the two vertebrae, which may be derived from the patient's pelvic bone. Recent advancements such as minimally invasive spinal fusion surgeries use a smaller incision than traditional surgery, preserving the muscle attachments to the spine, which leads to a faster recovery than conventional surgery and reduced chances for specific problems.