What are the indications for posterolateral lumbar fusion surgery?
The purpose of a fusion is to stabilize the spine by providing an area of bone growth between two vertebral segments. In a posterolateral fusion, bone is placed in the posterolateral gutters of the spine on top of the transverse processes which are the lateral extensions of the vertebral bodies. The most common indication for a posterolateral fusion is to supplement a lumbar laminectomy procedure when there is spondylolisthesis in addition to spinal stenosis. A lumbar laminectomy procedure can cause further instability and worsening back pain in a spine that is already showing weakness. Other spine deformity conditions such as scoliosis and kyphosis may require a fusion. On occasion, a significant amount of the facet joint needs to be removed in order to decompress a nerve which can lead to further segmental instability and worsening back pain. A fusion will provide the additional stability to prevent the spine from further deterioration at that segment.
How is a posterolateral fusion performed?
The surgery is done under general anesthesia. A posterolateral fusion is usually performed with a lumbar laminectomy surgery.To perform a posterolateral fusion, the facet joints and the transverse processes need to be exposed by separating these bony structures from the overlying muscles. The bone that is removed during the laminectomy surgery is placed along the side of the facet joints on top of the transverse processes. A fusion enhancing material called bone morphogenic protein (BMP) is usually mixed in to promote mature bone to grow. It usually takes about 6 months for a mature bony island to form between the 2 vertebral segments. To supplement the fusion process and to provide immediate stabilization fixation to the spine, titanium screws and rods known as a pedicle screw system is used. The pedicle screw system will not interfere with future MRI if needed or set off alarms at airports. The surgical time can vary from 3-6 hours (sometimes longer) depending on the complexity of the case.
What is the recovery from a lumbar fusion surgery?
The hospital stay usually varies from 2-5 days depending on the extent of surgery and overall condition of the patient. Most patients go home with home care help setup such as a visiting nurse and a physical therapist. Some patients may benefit from a short stay (several weeks) at a rehab facility. There is usually back discomfort from the incisional area. The incisional pain usually significantly improves within 6-8 weeks. The nerve pain (pain involving the buttock and leg, if present) may resolve immediately after the surgery or may persist for a longer period due to inflammation. In most instances, there is a significant improvement in the nerve pain by 6-8 weeks. The nerve pain symptoms can continue to improve for up to 1-2 years after the surgery. Activity recommended for first 2 weeks after surgery is short walks and mainly rest. Physical therapy guidance is recommended from 2-3 weeks after surgery for 6-8 weeks. Return to work can vary depending on the extent of surgery, rate of recovery, and physical demands of the job. For a nonphysical job, reasonable timeline to return to work is 3-4 weeks to 3 months whereas more labor intensive work may require to be out of work for up to 3-6 months.