Lumbar spinal surgery is used to correct problems with the spinal bones (vertebrae), disks, or nerves of the lower back (lumbar spine).

Description
             The spine consists of bones (vertebrae) separated by soft cushions (disks). Pressure on the nerves that branch off the spinal cord can produce pain, numbness, tingling, or weakness. Lumbar spinal surgery is done while you are under general anesthesia. A surgical cut is made over the area of the problem. The bone that curves around and covers the spinal cord and the tissue that presses on the nerve or spinal cord are removed. The hole through which the nerve passes may be widened to prevent further pressure on the nerve. Sometimes, spinal fusion is necessary to stabilize the area.
                                       

Herniated lumbar disk
             When part or all of the soft, gelatinous central portion of an intervertebral disk (the nucleus pulposus) is forced through a weakened part of the disk it is called herniated lumbar disk is a condition in which, resulting in back pain and nerve root irritation.

Why the Procedure Is Performed
Symptoms of lumbar spine problems that may require surgery at some point include:
Pain that extends (radiates) from the back to the buttocks or back of thigh
Pain that interferes with daily activities
Weakness of legs or feet
Numbness of legs, feet, or toes
Loss of bowel or bladder control
             Patients with spinal pain in the neck or back are usually treated conservatively before surgery is considered. This includes bedrest, anti-inflammatory medications, physical therapy, braces, and exercise. Maintaining good health, muscle strength, and body posture with appropriate rest and exercise help prevent unnecessary strain on the spine and muscles.

Risks
Risks for any anesthesia include the following:
Reactions to medications
Problems breathing

Risks for any surgery include the following:
Bleeding
Infection

Additional risks of spinal surgery include the following:
Nerve damage leading to paralysis
Blood clots
Muscle weakness
Loss of bowel or bladder control
             In a postero-lateral gutter fusion procedure, the spine is approached from the back. Bone graft is taken from the pelvis and laid out in the postero-lateral portion of the spine that is to be fused. The back muscles hold the graft in place until it fuses with the vertebrae. A fusion will setup within three months and will continue to get stronger for one to two years.
                                       

             Pedicle screws are used sometimes in a spinal fusion to add extra support and strength to the fusion while it heals. Pedicle screws are placed above and below the vertebrae that were fused. A rod is used to connect the screws which prevents movement and allows the bone graft to heal. After the fusion is completely healed, the screws and rods can be removed. Removal isn't necessary unless they cause the patient discomfort.

                                       
             Inter-body cage fusion uses a hollow threaded titanium or carbon fiber cylinder to fuse two vertebrae together. The diseased disk is removed and two inter-body cages are placed in the opening where the diseased disk has been removed. The cages are filled with bone graft. The bone grows through the holes in the cages fusing the vertebrae.

Prognosis
             How long you must stay in the hospital depends on the type of spinal surgery performed. Some people only stay overnight, while others must stay in much longer.
             You will be encouraged to walk the first or second day after surgery to reduce the risk of blood clots (deep venous thrombosis).
Complete recovery takes about 5 weeks. Heavy work is not recommended until several months after surgery or not at all

Video

Reference: MedlinePlus,ORLive