What is a Microdiscectomy?
Microdiscectomy is a surgical procedure performed to relieve pressure on a nerve that is causing arm or leg pain. Most commonly this is performed in the lower back (lumbar spine) and the procedure is called a lumbar microdiscectomy.
A patient is a good candidate for a lumbar microdiscectomy if they have a herniated disc in the lower back causing a lumbar radiculopathy or sciatica, which is radiating leg pain that is more severe than the back pain, and the symptoms have been persistent for more than 6 weeks despite conservative treatment with physical therapy, medications, or epidural steroid injections.
Surgery is sometimes recommended sooner if patients have significant weakness or numbness.
Lumbar microdiscectomy is performed under general anesthesia. The patient is positioned prone (face down on their belly) on the operating table.
After cleaning the skin and placing sterile drapes, a small incision (less than 1 inch) is made over the operative level which is localized using x-ray.
The surgery is performed minimally invasively by using specialized dilating tubes which allows access to the spine and the nerves without cutting through the back muscles, but rather spreading them apart. A microscope is used to provide clear visualization of the spine. A small window is made in the bone using a high-speed burr to provide access to the spinal canal.
Using microsurgical techniques the nerve is gently pushed to the side to access the herniated disc fragments which are dissected free and removed. The entire disc between the bones is not removed; rather, just the pieces of disc that are putting pressure on the nerves and causing the pain. After the disc fragments are removed, the retractor providing access to the spine is removed and the incision is closed.
What To Expect After Microdiscectomy Surgery?
Lumbar microdiscectomy typically provides excellent relief of sciatica pain running down the leg. This is often immediate with patients feeling improvement in their leg pain as soon as they wake up from anesthesia.
Often patients are pain free within 3-4 days after microdiscectomy surgery and no longer require strong pain medication. Sometimes, full resolution of leg pain can take weeks to months and in rare cases may not completely go away depending on how long the symptoms have been present. Weakness and numbness can take weeks to months to recover, and in some cases may not recover completely.
Most patients can go home on the day of lumbar microdiscectomy surgery although some patients may stay overnight in the hospital or surgery center before going home.
Walking for exercise is encouraged immediately although for the first 6 weeks after microdiscectomy surgery there are certain restrictions to limit the risk of re-herniation, or another piece of disc material herniating at the same level into the spinal canal and causing a recurrence of leg pain.
These restrictions are no bending, twisting, or lifting, pushing, or pulling > 10 lbs. After 6 weeks, patients can gradually return back to their usual activities without any formal restrictions but should ease slowly back into vigorous activity with a special focus on isometric core strengthening (e.g. planks).
Post-operative visits are recommended at 2 weeks, 6 weeks, and 3 months after microdiscectomy surgery.
Microdiscectomy Surgery Risks
While all spinal operations carry some risks, in general the risks of microdiscectomy surgery are low.
The most common risks of lumbar microdiscectomy surgery are:
Risk of re-herniation of disc material at the same level. This can cause recurrent leg pain that was similar to the pain that was present before microdiscectomy surgery. This occurs in approximately 10% of patients. A first-time recurrent disc herniation can often be treated with another microdiscectomy procedure, but a second-time reherniation is usually treated with a spinal fusion.
Persistent back pain, leg pain, numbness, and weakness. Even if the surgery is successful and the herniated disc fragments are removed, there can be permanent damage to the nerve from the disc herniation that can be slow to recover or may never recover
Risk of a dural tear. The dura is the thin membrane which encloses the nerves and the spinal fluid or CSF. Dural tears occur in approximately 5% of microdiscectomy procedures. When these occur, they are sutured or patched to repair the dural tear, and the patient is typically kept on flat bedrest for several days in the hospital to allow the dural tear to heal.
Risk of injury to a nerve is rare but is possible as the nerves need to be dissected free of the herniated disc and pushed to the side to be able to remove the disc herniation