Your Guide to Spinal Fusion Surgery

The spine is a complex structure that connects the upper and lower body. It is made up of vertebrae, disks, a spinal cord, and nerves. The vertebrae are the bones of the spine. Between the vertebrae are disks, which are cushioning pads that function as shock absorbers and allow for movement. The spinal column is held in alignment by ligaments, cartilage, and muscles that surround and protect the spinal cord membranes and the nerves that branch out from the spinal cord to all the parts of your body.

The segments of the spine are cervical (neck), thoracic (chest), lumbar (lower back), sacrum (back wall of the pelvis area), and coccyx (lower extremity of the spine).

The spine provides mobility, such as turning, twisting, and bending; and strength to stand, walk, and lift. Common problems affecting the spine include herniated disks, osteoporosis, fractures, and sprains and strains.

Herniated disk–Also called a slipped disc or a ruptured disc; when one of the disks that cushions and separates the bones of the spine herniates, or ruptures, and part of the gel-like substance in the center of the disc pushes out of the thick, outer ring of disc cartilage toward the spinal canal, putting pressure on the extremely sensitive spinal nerves. The most common symptom is sciatica, a sharp pain extending from the buttocks down the back of one or both legs.

Osteoporosis–Age-related softening of the bones that causes the spine to wear and collapse, resulting in severe pain and a progressive hunchback.

Fracture–Fracture of part of the spinal column is a serious injury usually caused by high-energy trauma like a car crash, fall, sports accident, or gunshot wound. Symptoms include moderate to severe back pain made worse by movement, and, when the spinal cord is also involved, numbness, tingling, weakness, and bowel and/or bladder dysfunction. Fractures are classified based on the pattern of the injury:

• Compression fracture–The front of the vertebra is broken, but the back of the vertebra is not.
• Axial burst fracture–The front and back of the vertebra is broken; often caused by a fall from a height in which a person lands on his feet.
• Flexion/distraction (chance) fracture–The vertebra is pulled apart; can occur in a head-on car crash in which the upper body is thrown forward while the pelvis is stabilized by a lap seat belt.
• Transverse process fracture–This type of fracture results from rotation or extreme side bending.
• Fracture-dislocation–In this injury, one vertebra moves off the adjacent one.
• Spondylolysis–Stress fracture, with mild pain that may radiate to the buttocks and legs, and is worse with activity and better with rest; pain usually spreads across the lower back and may feel like a muscle strain; may lead to muscle tightening that changes the gait; can lead to spondylolisthesis.

Sprain–Occurs when a sudden, forceful movement injures a ligament which has become stiff or weak through overuse or poor conditioning.

Strain–Injury to a muscle that is poorly conditioned or overworked.

Other problems of the spine include the following:

Discogenic pain–Different from a herniated disc; the outer ligament tissue of a disc frays or tears from use or injury, allowing nerves and small blood vessels from the soft disc center to seep into the injury site, triggering pain receptors in the ligament tissue; the pain originates from the disc, is confined to the back, and does not move down the legs.

Cauda Equina Syndrome (CES)–A rare disorder affecting the bundle of nerve roots (cauda equina) at the lower end of the spinal cord; occurs when the nerve roots are compressed and paralyzed, cutting off sensation and movement; can lead to permanent paralysis, impaired bowel and bladder control, and other problems; may be caused by a ruptured disc, tumor, infection, fracture, narrowing of the spinal cord, a violent impact from a crash or fall, penetrating injury (such as a stab or gunshot), or by a congenital abnormality.

Kyphosis–A curve that results in an exaggerated round-back; the condition may be caused by a variety of disorders:

• Postural kyphosis–An exaggerated but flexible increase of the natural curvature of the spine that usually becomes noticeable in adolescence; does not lead to problems in adult life.
• Scheuermann's kyphosis–A condition in which vertebrae become wedged, causing a rounded or hunched back; a common cause of middle back pain in adolescents.
• Congenital kyphosis–Condition in which the spinal column of an infant did not develop normally in the womb, and several vertebrae are fused together, causing progressive kyphosis as the child grows.

Sciatica–Also called lumbar radiculopathy, this condition causes pain in the lower back or hip that radiates from the buttocks to the back of one thigh and into the leg; may also cause weakness, numbness, or a burning or tingling sensation down the leg; the condition is most common in people 30-50 years old; may be caused by general wear and tear and by sudden pressure on the disks that cushion the vertebrae.

Scoliosis–Side-to-side spinal curves that can occur at any age; some of the bones in a scoliatic spine may also rotate slightly, making the waist or shoulders appear uneven; does not usually cause any pain.

Spinal stenosis–The discs in the front of the spine become dehydrated as a result of aging and the joints in the back of the spine overgrow as a result of arthritis; over time, these changes can lead to narrowing (stenosis) of the spinal canal; that can pinch nerves that control muscle power and sensation in the legs; pinched nerves can also become inflamed and cause pain in the buttocks; the ability of the spine to carry the load of the upper body can be diminished, leading to the forward slippage of one vertebra on another (spondylolisthesis).

Spondylolisthesis–Slipped vertebrae, or the occurrence of one vertebra shifting forward on the vertebra below; usually occurs at the base of the spine and can cause both back and leg pain.

Infection–In young children, infection in a disk space (diskitis) can lead to back pain; typically affects children aged 1-5, but can also affect older children and teenagers.

Tumor–Rarely, tumors can be responsible for constant and progressive back pain that is unrelated to activity.

Source: American Association of Orthopaedic Surgeons