Lumbar Spine Surgery
What makes up the lumbar spine?
The lumbar spine is also sometimes referred to as the lower back. But in the case of the lower back, we have to include both the lumbar vertebrae and the sacrum. The lumbar spine consists of 5 Lumbar vertebrae which are numbered from L1 to L5. The lumbar vertebrae is the part of the spine which bears the weight of the upper body including the head and neck, and is therefore designed specifically for weight bearing. These vertebrae are the largest in the spine and they have a thick, wide, kidney shaped, vertebral body designed for weight bearing. The pedicles, lamina, articular processes, facet joints and transverse processes are all bigger and stronger than the rest of the vertebrae which make up the spine.
Below the lumbar spine you have the sacrum, which is made up of 5 vertebrae fused together forming a single bone. The sacrum then fuses with the pelvic bones on either side, at the sacroiliac joint.
In between these vertebrae you get the intervertebral discs, which are rounded structures which act as shock absorbers and flexible pivots for movement. The discs are made up of two components, the outer fibrous part called the annulus fibrosus and the inner gel like substance called nucleus pulposus. The lumbar intervertebral segments are named according to the vertebrae they are found between.
It is the vertebral column in our body which houses the spinal cord. In adults the spinal cord ends at the level between L1 and L2, after which you will find the structure called the cauda equina. Which is a bundle of nerves enclosed within a thick sac of fluid, and resembles a horse tail. The nerves that make up the cauda equina, which control the functions and sensations in the leg, exit the vertebral column through small openings on either side of the lumbar spine called the lateral foramina.
This is what makes up the structure of the lumbar spine, and an understanding of this is important as it helps to get a clear idea of what can actually lead to lumbar spine problems and how to manage these conditions.
What conditions lead to pain in the lumbar spine?
Lower back pain is a condition which plagues people of all ages. And you will find that the majority of individuals have persistent, chronic lower back pain, which they have gotten used to living with. There are many different causes for lumbar spine pain, which include:
- Muscle pain – problems with the musculature which surround and support the lumbar spine is a common cause of lower back pain. Strenuous exercise or lifting of heavy objects can lead to what is known as muscle spasm or strain, commonly referred to as a pulled back muscle.
- Disc degeneration – which occurs as a result of wear and tear in the discs. Which leads to abnormalities in the shape and structure of the disc, which then leads to abnormal movements of the lumbar spine leading to pain.
- Lumbar disc herniation – is a condition where part of the intervertebral disc is pushing into the spinal canaland pressing on the nerves which are exiting the vertebral column leading to pain. This herniation can occur as a result of degeneration or due to sudden lifting of a heavy weight.
- Sacroiliac joint dysfunction – if there is any abnormality of the joint space such as narrowing or abnormalities of the bony surface which form the joint, it can lead to either restricted movement or too much movement resulting in pain.
- Spondylolisthesis – is the slipping of one vertebral body in front of the other. This slipping usually occurs in the vertebra which lies below and leads to narrowing of the lateral foramina. This leads to nerve compression and pain.
- Osteoarthritis – also called facet join arthritis is a condition where the cartilage covering these joints become worn off with time or too much movement. This leads to increased friction during movement and formation of bone spurs (excess bone), which leads to joint swelling and tenderness, as well nerve compression and restricted movement.
- Lumbar stenosis – is the narrowing of the spinal canal in the lumbar region which can be caused as a result of disc herniation, or swelling and bone spur formation due to osteoarthritis. Stenosis will lead to nerve compression and pain.
In most of the above mentioned conditions it is the spinal nerves which become compressed. These nerves serve to supply the motor and sensory function of the lower limbs. Therefore, when they are compressed, along with lower back pain, most people complain of pain at the back of the thigh radiating to the sole, a condition termed as sciatica.
What happens during lumbar spine surgery?
The main aim behind carrying surgery on the lumbar spine is to relieve the pressure on the spinal cord and nerves which is the cause of the pain and other symptoms that the patient is experiencing.
The different surgical approaches to lumbar spine surgery include:
- Fusion surgeries - are surgeries where two or more vertebrae that make up the column are joined together. It involves the preparation of the intervertebral disc space by removing the disc and replacing it with bone cement, allograft or other implants which will hold the adjacent vertebrae in place. Rods and screws might also be used following this in order to provide further stability. There are three common approaches to this surgery, which include:
- Posterior Lumbar Interbody Fusion (PLIF) – where the incision is made on the patient’s back
- Anterior Lumbar Interbody Fusion – where the incision for access to the vertebrae is made on the patient’s abdomen anteriorly
- Transforaminal Lumbar Interbody Fusion – where the incision is made on the patient’s back, but the vertebral column is approached from the side.
- Pedicle screw fixation – which makes use of metal rods and pedicle screws that are used to stabilize the various segments of the spine, and helps to keep the bone cement which has been inserted in place, in order to help the healing process of the bone as well. The rods and screws which are inserted can be later removed once healing is completed and your doctor is certain that your spine is stable. But usually they are not removed unless pinching your nerves.
- Microdisectomy – which is used to treat disc herniation causing pain, by removing the part of the disc which has herniated and is causing the compression of the spinal nerves.
- Minimally Invasive Spine Surgery (MISS) – is a procedure which is becoming increasingly popular to treat conditions like canal stenosis, degenerative disc disease and intervertebral disc herniation, because it is a less invasive procedure compared to open spine surgery and therefore causes less tissue damage.
- Foraminotomy – is a procedure which is carried out in the case of nerve compression at the transverse foramen where the nerves exit the vertebral column. During this procedure, this foramen is enlarged by removing bone material.
- Vertebroplasty and Kyphoplasty, are procedures which are carried out to treat vertebral fractures, where the defect on the bone is corrected using bone substitute called bone cement, which helps to stabilize the broken bone, and regain the support of the backbone.
What are the possible risks and complications of lumbar spine surgery?
As with any major surgery lumbar spine surgery also has its potential risks and complications, which include:
- Damage to nerves, which can lead to numbness or weakness of the lower limbs
- Damage to major vessels in that region
- Formation of blood clots
- Infection at the surgical site
How do I recover from lumbar spine surgery?
The recovery from lumbar spine surgery depends on individual factors. Usually you will have a hospital stay of about 5-7 days, during which you will be introduced to a physical therapist, who will help you with mobility. If MISS procedure done without screws, Usually your doctor will ask you to walk unassisted the very next day following surgery although you will be asked to take things easy for about 4-6 weeks following surgery. If you have been treated with screws, under cover of analgesics, mobility usually starts on 3rd day. Follow-up investigations such as X-rays and other imaging studies will be done in order to determine the success of surgery.