Spinal surgery

Lumbar discectomy is a surgery to remove a herniated or degenerative disc in the lower spine. The incision is made posterior, through the back muscles, to remove the disc pressing on the nerve. Most herniated discs heal after a few months of nonsurgical treatment. Only 10% of people with herniated disc problems have enough pain after 6 weeks of nonsurgical treatment to consider surgery.

Figure: A disc herniates when the nucleus pushes against a weakened annulus, causing it to bulge outward. This puts pressure on the nerves and causes pain. If the annulus is very worn or injured, the jelly-like nucleus may squeeze all the way through.

 Procedure:

• You will lie on your back on the operative table and be given anesthesia and antibiotics. Once asleep you are placed onto your stomach with your chest and sides supported by pillows and all areas protected. The area where the incision will be made is cleansed and prepped with antiseptic solution.

• Incision: With the aid of a fluoroscope (a special X-ray), I will pass a thin needle through the skin down to the bone to locate the affected vertebra and disc. A skin incision is made down the middle of your back over the affected vertebrae. The length of the incision varies on the size of the patient and how many discectomies will be performed. A single-level incision is about 6-10 centimetres long. The back muscles are retracted on one side to expose the bony vertebra. An X-ray is taken to verify the correct vertebra.

• A laminotomy : sometimes next, a small opening of the lamina, above and below the spinal nerve, is made with bone- biting tools A laminotomy can be done on one (unilateral) or both (bilateral) sides, or on multiple vertebrae levels. This is only done if needed to provide safe access to the disc.

• Removal of the disc fragments: with the lamina removed, I will gently retract the protective sac of the nerve root. I look through surgical microscopic loupes to find the herniated disc. Only the ruptured portion of the disc is removed to decompress the spinal nerve root. The entire disc is not removed Bone spurs or a synovial cyst that may press on the nerve root are also removed.

• For a single-level lumbar discectomy, fusion is rarely performed. However, other conditions, such as recurrent disc herniation or spinal instability, may be treated with a fusion.
• Closing the incision: the retractor holding the muscles is removed. The muscle and skin incisions are sewn together with sutures and absorbable sutures to skin and glue. Steri-strips are placed across the incision.

What are the results?

Good results are achieved in 80 to 90% of patients treated with lumbar discectomy. Discectomy may provide faster pain relief than nonsurgical treatment. About 5 to 15% of patients will have a recurrent disc herniation, either at the same side or the opposite side.

Anterior Cervical discectomy involves removing the damaged disc from the front (anterior) of the spine through the throat area. By moving aside the neck muscles, trachea, and esophagus, the disc and bony vertebrae are exposed. Surgery from the front of the neck is more accessible than from the back (posterior) because the disc can be reached without disturbing the spinal cord, spinal nerves, and the strong neck muscles. Depending on your particular symptoms, one disc (single-level) or more (multi- level) may be removed during your surgery.

After the disc is removed, the space between the bony vertebrae is empty. To prevent the vertebrae from collapsing and rubbing together, a cage is used as a spacer or a piece of bone graft is inserted to fill the open disc space. The graft serves as a bridge between the two vertebrae to create a spinal fusion. The bone graft and vertebrae are fixed in place with a bone graft or allograft or bone substitute and metal plates and screws. It may also be filled with a cage packed with graft and screws through this cage.

After surgery the body begins its natural healing process and new bone cells grow around the graft. After 3 to 6 months, the bone graft should join the two vertebrae and form one solid piece of bone. The instrumentation and fusion work together, similar to reinforced concrete.

• Procedure: you will lie on your back on the operative table and be given anesthesia and antibiotics. Once asleep you are placed onto your stomach with your chest and sides supported by pillows and all areas protected. The area where the incision will be made is cleansed and prepped with antiseptic solution.
• If a fusion is planned and your own bone is to be used, the hip area is also prepped to obtain a bone graft. If a donor bone / artificial graft or graft substitute is used, the hip incision is unnecessary.
• Incision: a 6-8cm skin incision is made on the right or left side of your neck. I will make a tunnel to the spine by moving aside muscles in your neck and retracting the trachea, esophagus, and arteries. Finally, the muscles that support the front of the spine are lifted and held aside so I can clearly see the bony vertebrae and discs.
• Identifying the damaged disc: with the aid of a fluoroscope (a special X-ray), a thin needle into the disc to locate the affected vertebra and disc. The vertebrae bones above and below the damaged disc are spread apart with a special retractor.
• Removal of the damaged disc: the outer wall of the disc is cut. The surgeon removes about 2/3 of your disc using small grasping tools, and then I use surgical microscopic loupes to remove the rest of the disc. The ligament that runs behind the vertebrae is removed to reach the spinal canal. Any disc material pressing on the spinal nerves is removed.
• Bone graft fusion: using a drill, the open disc space is prepared on the top and bottom by removing the outer cortical layer of bone to expose the blood-rich cancellous bone inside. This “bed” will hold the bone graft material that you and your surgeon selected.
• Bone graft from your hip: a skin and muscle incision is made over the crest of your hipbone and bone graft taking from there.
• Cage Insertion: the cage is placed in the disc space and screws attached to the vertebral body above and below. X ray check of the position of the cage and screws is undertaken.
• Closing the incision: the retractor holding the muscles is removed. The muscle and skin incisions are sewn together with sutures and staples to skin and glue. Steri-strips are placed across the incision.
  

What are the results?

Anterior cervical discectomy is successful in relieving arm pain in 90 to 100% of patients. Neck pain is relieved in 70 to 85% of patients. In general, people with arm pain benefit more from ACDF than those with neck pain. Aim to keep a positive attitude and diligently perform your physical therapy exercises.

What is a spine fusion?

A spinal fusion is to repair damaged discs and realign bones causing back or leg pain. There are several ways to reach the spine and perform a fusion.  If you have spinal instability or have laminectomies to multiple vertebrae, a fusion may be performed. Fusion is the joining of two vertebrae with a bone graft held together with hardware such as plates, rods, hooks, pedicle screws, or cages. The goal of the bone graft is to join the vertebrae above and below to form one solid piece of bone. There are several ways to create a fusion. The right one for you depends on your own choice and your doctor’s recommendation.

The most common type of fusion is called the posterolateral fusion. The topmost layer of bone on the transverse processes is removed with a drill to create a bed for the bone graft to grow. Bone graft, taken from the top of your hip, is placed along the posterolateral bed. The surgeon may reinforce the fusion with metal rods and screws inserted into the vertebrae. The back muscles are laid over the bone graft to hold it in place.

 For the most common fusion been posterior an incision is made off the middle of the back. The facet joint is removed to enlarge the foramen opening for the nerve. Bone spurs and ligaments are removed to decompress the nerve. The damaged disc will be removed and using bone graft or artificial graft or donor graft the posterior bony areas will fuse. The graft becomes a bridge between the two bones to promote fusion. The graft is strengthened with metal screws and rods. Sometimes a cage is placed into the disc space to restore anterior height or to aid in decompression of nerves.

As the body begins to heal, new bone grows around the graft. After 3 to 6 months, the graft should fuse the two vertebrae into one solid piece of bone. Like reinforced concrete, instrumentation and fusion work together.

 TLIF (Transforaminal Lumbar Interbody Fusion) fuses both the front disc space and the back facet joints, stopping all motion at that spine level.  Depending on the symptoms, a one-level or multi- level fusion may be performed. A one-level fusion joins two bones while a two-level fusion joins three bones. Fusion will take away some flexibility in your spine, but most patients will not notice.  Recovery time can take up to 12 -20 weeks.

Procedure

• You will lie on your back on the operative table and be given anesthesia and antibiotics. Once asleep you are placed onto your stomach with your chest and sides supported by pillows and all areas protected. The area where the incision will be made is cleansed and prepped with antiseptic solution.
• Incision : An x-ray fluoroscope or image guidance is used to plan the approach. A 7-10 incision in the midline over the specific disc level
• Navigation: most spinal fusions undertaken by Dr Leigh use spinal navigation software to help accurately place the pedicle screws used during the procedure. This involves a pre-operative CT scan and intra-operative mapping of the anatomy to increase surgical accuracy.
• Removal of the facet joint / disc: a portion of the bony lamina and facet joint is removed. This opens the spinal canal and exposes the dura sac protecting the nerves. Bone spurs and ligament are removed to free the nerve. The nerve is gently retracted so the surgeon can remove the disc nucleus The disc annulus remains in place to hold the bone graft cage if used. If not indicated the disc is not removed.
• Disc Space Preparation: bone shavers are used to prepare the fusion bed. The open disc space is measured and a spacer size is selected. The trial spacer is slid into the empty disc space. An x-ray is taken to ensure that the depth, placement, and wedge angle create sufficient height and decompress the nerves.
• When a good fit is made, the bone graft material is prepared for the fusion. The mortar-like paste contains bone-growing proteins that are packed into the permanent bioplastic spacer cage. Guided by x-ray fluoroscopy, the permanent spacer cage is inserted into the empty disc space, pushing the two bones to restore normal disc height.
• Pedicle Screw Insertion: two sets of pedicle screws are placed in the bone above and below the operated disc space and on both the right and left sides of the spine. Navigation aids this insertion. A rod is passed to connect two screws together.
• In cases of spondylolisthesis, the surgeon pulls on the screws to realign the bones before securing them to the rod. The hardware provides stability during fusion.
• Closing the incision: the retractor holding the muscles is removed. The muscle and skin incisions are sewn together with sutures and absorbable sutures to skin and glue. Steri-strips are placed across the incision.

What is a spinal decompression?

Spinal stenosis is often caused by age-related changes: arthritis, enlarged joints, bulging discs, bone spurs, and thickened ligaments. Spinal decompression can be performed anywhere along the spine from the neck (cervical) to the lower back (lumbar). The surgery is performed through an incision in the back (posterior) muscles. The lamina bone forms the backside of the spinal canal and makes a roof over the spinal cord. Removing the lamina and thickened ligament gives more room for the nerves and allows for removal of bone spurs (osteophytes). Depending on the extent of stenosis, one vertebra (single-level) or more (multi-level) may be involved. 

Figure: Spinal stenosis occurs when the space around the spinal cord narrows. This puts pressure on the spinal cord and the spinal nerves. When intervertebral discs narrow and arthritis develops new bone can be formed. Over time, this bone overgrowth or spurs can lead to a narrowing of the spinal canal. The ligaments that connect vertebrae can also thicken which can also narrow the spinal canal.

 There are several types of decompression surgery:

• Laminectomy is the removal of the entire bony lamina, a portion of the enlarged facet joints, and the thickened ligaments overlying the spinal cord and nerves.

• Laminotomy is the removal of a small portion of the lamina and ligaments, usually on one side. Using this method the natural support of the lamina is left in place, decreasing the chance of spinal instability. Sometimes an endoscope may be used, allowing for a smaller, less invasive incision.
• Foraminotomy is the removal of bone around the neural foramen – the canal where the nerve root exits the spine. This method is used when disc degeneration has caused the height of the foramen to collapse and pinch a nerve.
• Laminaplasty is the expansion of the spinal canal by cutting the lamina on one side and swinging them open like a door. It is used only in the neck (cervical) area.
• Discectomy is the removal of a portion of a bulging or degenerative disc to relieve pressure on the nerves.

Procedure: you will lie on your back on the operative table and be given anesthesia and antibiotics. Once asleep you are placed onto your stomach with your chest and sides supported by pillows and all areas protected. The area where the incision will be made is cleansed and prepped with antiseptic solution.

• Incision: a skin incision is made down the middle of your back over the appropriate vertebrae. The length of the incision depends on how many laminectomies are to be performed. The strong back muscles are split down the middle and moved to either side exposing the lamina of each vertebra.

• Laminectomy or laminotomy: once the bone is exposed, an X-ray is taken to verify the correct vertebra.

• Laminectomy: The bony spinous process is osteotomised and moved to the side. Next, the bony lamina is removed with bone-biting tools. The thickened ligamentum flavum that connects the laminae of the vertebra below with the vertebra above is removed. This is repeated for each affected level
• Laminotomy: In some cases, the entire protective bony lamina may not have to be removed. A small opening of the lamina above and below the spinal nerve may be enough to relieve compression. Laminotomy can be done on one side (unilateral) or both sides (bilateral) and on multiple vertebrae levels. 
• Decompress the spinal cord + spinal nerve roots : once the lamina and ligamentum flavum are removed the protective covering of the spinal cord (dura mater) is visible. The surgeon can gently retract the protective sac of the spinal cord and nerve root to remove bone spurs and thickened ligament. The facet joints, which are directly over the nerve roots, may be undercut (trimmed) to give the nerve roots more room. Called a foraminotomy, this manoeuvre enlarges the neural foramen (where the spinal nerves exit the spinal canal). If a herniated disc is causing compression the surgeon will perform a discectomy.

• Closing the incision: the retractor holding the muscles is removed. The undersurface of the spinous process is checked for any bony spurs. The muscle and skin incisions are sewn together with sutures and absorbable sutures to skin and glue. Steri-strips are placed across the incision.

What are the results?

Decompressive laminectomy is successful in relieving leg pain in 70-90% of patients allowing significant improvement in function (ability to perform normal daily activities) including walking ability and markedly reduced level of pain and discomfort. However, back pain may not be relieved.

No surgery is without risks. General complications of any surgery include bleeding, infection, blood clots, and reactions to anaesthesia. If spinal fusion is done at the same time as a laminectomy, there is greater risk of complications

The risks for fusion are the same as for any surgical procedure on the spine but because of the placement of rods and screws there are specific risks that apply to this procedure.

Nerve damage or persistent pain. Any operation on the spine comes with the risk of damaging the nerves or spinal cord. Damage can cause numbness or even paralysis. However, the most common cause of persistent pain is nerve damage from the stenosis. Some bone spurs may permanently damage a nerve making it unresponsive to decompression surgery.

Vertebrae failing to fuse. Among many reasons why vertebrae fail to fuse, common ones include smoking, osteoporosis, obesity, and malnutrition. Smoking is by far the greatest factor that can prevent fusion. Nicotine is a toxin that inhibits bone-growing cells. If you continue to smoke after your spinal surgery, you could undermine the fusion process.

Deep vein thrombosis (DVT) is a potentially serious condition caused when blood clots form inside the veins of your legs. If the clots break free and travel to your lungs, lung collapse or even death is a risk. However, there are several ways to treat or prevent DVT. If your blood is moving it is less likely to clot, so an effective treatment is getting you out of bed as soon as possible. Drugs can also be used to decrease the risk.

Hardware fracture. The metal screws, rods and plates used to stabilize your spine are called “hardware.” The hardware may move or break before your vertebrae are completely fused. If this occurs, a second surgery may be needed to fix or replace the hardware.

Adjacent Segment Disease.  This syndrome occurs when the vertebrae above or below a fusion take on extra stress. The added stress can eventually degenerate the adjacent vertebrae and cause pain.

Usually you can drive after the first clinic follow up appointment 10-14 days post-surgery. In cases of fusion this time may be delayed.

For the first 6 weeks after surgery the main activity is walking and avoiding lifting, bending and twisting. You can get back on an exercise bike at 2 weeks and can return to supervised gym-based activities at 6 weeks.

To avoid deep vein thrombosis (DVT) I use mechanical compression machines to pump the blood around your legs during surgery and TED stockings. We also promote early movement with walking around the day of your surgery. Routinely we use 6 weeks of aspirin for prophylaxis, but this will be modified if you have risk factors and other medications may be used. Talk to Warren at the time of your appointment for your specific regime.

You will be seen 10-14 days after surgery and a rehabilitation program will be discussed. Usually you are reviewed at 6 weeks and 12 weeks post-surgery and 6 months or until you have achieved a good or excellent result post-surgery.

For a discectomy operation you will not usually require a catheter but for decompressions and fusion surgery it is usually kept in for 24-48 hours.

Depending on the surgical procedure the post op pain management regime will be discussed between yourself, Warren and the anaesthetist to make sure your pain is kept manageable and allow mobilisation