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Lumbar Dural Tear

What is a Dural Tear?

A dural tear is a cut or tear in the lining of the sac containing the spinal cord, spinal fluid, and spinal nerves. It happens most commonly by accident during a spinal surgery. Spinal fluid can leak out through this tear and collect in a pouch. This is called a “pseudomeningocele”.

Dural tears can also occur by themselves due to extreme thinning of the dural sac from disease or age for example.

How often do Dural Tears happen during Spine Surgery?

The rates at which these tears occur during spine surgery have been reported to be between 3 to 15%. However, it is thought that they occur more commonly during repeated spine surgery. This is mostly due to the fact that spine surgeons have to remove scar tissue during repeat surgeries of the spine, which makes an injury to the dural sac more likely.

Why do Dural Tears happen during some Spine Surgeries?

During spine surgery, such as removing a disc herniation (discectomy), the surgeon will work directly around the dural sac. Since sharp instruments are needed to remove spine tissue such as discs, an accidental nick in the dural sac can occur. Spinal fluid can often be seen escaping. Depending on which spinal level the surgeon is operating on, either spinal nerves or the spinal cord can often be seen through the tear in the dura. At times, the spinal nerves will also bulge out of the dural sac. Usually, the spinal nerves or spinal cord are not injured, but are simply placed back into the sac which is then closed with stitches. Often certain chemicals are placed on top of the dura to help seal it and not allow more spinal fluid to escape.

Sometimes, surgeons place a synthetic graft, or the patient’s own fascia or muscle tissue on top of the dural tear to help seal it.

The majority of patients do not have long-term problems from a dural tear.

What are the symptoms from a Dural Tear?

The most common symptom from a dural tear is a severe headache, which is usually worse in the front or on top of the head. It is often worse when trying to sit or stand, and improved when lying down.

Patients may also experience nausea, vomiting and light sensitivity.

How are Dural Tears diagnosed?

The diagnosis of a dural tear is often made at the time or surgery when the spinal fluid is seen escaping the dural sac. However, sometimes it is not apparent until after surgery. In that case, the following images can be helpful:

  1. MRI Scan

MRI scans show the spinal fluid inside the dural sac. However, the dura itself can be difficult to see. A small dural tear may not be obvious. Due to its larger size, a pseudomeningocele (collection of spinal fluid) can usually be seen.

      2. CT Scan

CT scans combined with a myelogram can show dural tears and pseudomeningoceles. However, a myelogram requires an injection through the dura into the spinal fluid. The fear is that the injection itself could cause another hole in the dura. So, this is not as commonly done unless the diagnosis cannot be confirmed any other way and surgery will very likely need to be done.

How are Dural Tears treated?

  1. Non-Surgical

Not all patients with a dural tear require surgery to fix it. At times, conservative care can be given while the tear closes itself:

A. Bedrest

Typically patients are kept at bed rest. As they improve, they can begin to sit up at small inclines.

B. Medications

Anti-nausea medication can help control the nausea from dural tears.

Pain killers can be helpful in controlling the headaches from dural tears

C. Caffeine

Caffeine given by mouth or intravenously can help with the headache symptoms

D. Hydration

Patients are often hydrated by IV which can help with the symptoms.

E. Lumbar Drain

In larger dural tears of the low back (lumbar spine), the surgeon can insert a small drain through the skin and into the spinal fluid above the level of the dural tear. This can lower the spinal fluid pressure on the dural tear and allow it to heal itself over time.

 

      2. Surgical

Surgery for larger dural tears and pseudomeningoceles is often required to improve the patient’s symptoms. If the tear is recognized during surgery, it is often closed right away.

However, dural tears which are not seen at the time of surgery and have not responded to the Non-Surgical care, will require another surgery to fit them.

During this surgery, the surgical wound is reopened and carefully explored until the dural tear is found. If possible, the tear is closed with stitches (sutures). Sometimes specific sealants (chemicals) are placed on top of that. Other times, surgeons will place a synthetic graft on top. Another option is using a piece of the patient’s fascia or muscle to place on top of the dural tear. These techniques depend on the surgeon’s preference and size of the dural tear or pseudomeningocoele.