Tag: lumbar discectomy

Lumbar Microdiscectomy Explained

Lumbar Microdiscectomy is one of the most common neurosurgical procedures performed in the United States each year.  This surgical procedure is a often performed to remove a herniated lumbar disc, which is a common condition.  Most of the time, a lumbar herniated disc causes severe shooting pain into the leg, often called lumbar radiculopathy.

The best way to understand this operation is to consider a recent case.

A middle aged patient presented to the office with moderate low back pain and severe pain shooting down the back of the thigh and around the knee.  It was severe and shooting in nature.  The patient said it was 7 out of 10 in severity, even while taking narcotic medications, which they received after an ER visit.

The first step in diagnosis of a herniated disc is clinical suspicion.  This is usually followed by an MRI or other imaging study to confirm the diagnosis.  In most cases, a

Axial T2 MRI. This image shows the right L2-3 disc herniation. When viewing MRI in the axial plane, the patient’s RIGHT side is on the left side of the screen.

CT Myelogram or MRI study is sufficient to identify a herniated disc.  If it explains the patient’s symptoms then surgery can be considered.

After the diagnosis of a herniated disc the patient usually has a trial of conservative (non-operative) treatment.  This may include physical therapy, chiropractic manipulation, steroids, other anti-inflammatories, gabapentin, or other medications.  If these treatments alleviate the patients’s pain then they may not require surgery.

If the patient has continued pain surgery may be considered.  Typically, surgery to remove a herniated disc is called a “lumbar hemilaminotomy and microdisectomy.”  This surgery is performed on the back.  A small incision is made over the spinal levels of interest (this is confirmed with x-ray or fluoroscopy at the start of surgery).  After making an midline incision, we dissect down to expose the lamina, or part of the bone overlying the dura.  This is done on the left or right side (it is done on the side that corresponds to the patient’s pain and side of disc herniation), at the level of the herniated disc.  A small window of bone is then removed with a drill to expose the ligament underneath.  Once the ligament is removed, we can see dura, or sac containing the lumbar nerve roots.  The models below show the location of this patient’s disc herniation and the planned lamina that will be removed.

Normal Lumbar Spine Model. The lumbar vertebrae are labeled L1 through L5.
Lumbar Spine Model, with red circle at the approximate location of the right L2-3 herniated disc, as seen on this patient’s MRI (above MRI images).
The yellow area is the planned area of bone removal (called a hemilaminotomy) to expose the dura and herniated disc.

In the images below we can see the view through the microscope during this microdiscectomy surgery.  We have exposed the dura, gently retract it medially, and then remove the herniated disc material.

Microscope View. For reference, the feet are on the left, the head is to the right, the top of the image is the midline, and the patient’s right is the bottom of the image. Here, we have removed the lamina and ligament, and the dura is in view. One can see a small amount of herniated disc material off to the right side of the dura, in the lateral gutter.
Microscope View. For reference, the feet are on the left, the head is to the right, the top of the image is the midline, and the patient’s right is the bottom of the image. Here, we have gently pushed the dura towards the midline to get a better view of the herniated disc material.
Microscope View. For reference, the feet are on the left, the head is to the right, the top of the image is the midline, and the patient’s right is the bottom of the image. Here, we have gently pulled a large fragment of disc up and out of the lateral gutter. It is sitting on top of the dura just prior to removal.

After removing the disc material, any bleeding is controlled with bipolar electrocautery.  The wound is irrigated out with an antibiotic saline solution, and the dura is covered with gelfoam.  The retractors are removed and the wound is closed.

This image shows the disc material removed in this particular surgery.

In this case, we were able to remove a large amount of herniated disc material.  The patient did quite well, with resolution of the leg pain shortly after surgery.