Lumbar spinal drainage using a needle to draw the cerebrospinal fluid (CSF) is a procedure done during brain surgery. The procedure is called a lumbar drain. Removing CSF helps the brain relax. But as you’ve discovered, complications such as a CSF leak can occur.
When that happens, a needle is inserted through the skin down into the thecal sac where the CSF is located. The thecal sac is made up of two separate but closely linked layers of lining called the dura mater and the arachnoid mater. The sac protects the nerve roots from pressure injury while the fluid supplies nutrients to the nerves.
Once the needle is in place, then a catheter can be inserted in place of the needle. The CSF is drained out through the catheter. The needle used to tap into the CSF is put in place using fluoroscopy. Fluoroscopy is a type of real-time X-ray that allows the surgeon to see the needle moving through the tissue. This type of X-ray improves accuracy but exposes both the patient and the surgeon to radiation.
Fluoroscopy has the added advantage of being portable. A unit can be brought to the patient’s room. The procedure can be performed at the bedside. But when several attempts to perform the procedure are not successful, then computed tomography (CT) may be helpful. The patient must be transported to the CT suite.
The CT scan allows safe and accurate placement of the needle from skin to spinal canal. Each cross-sectional slice provided by the CT image allowed the surgeon to choose the right needle angle. Measurements to gauge distances are given in millimeters. If there is any doubt about correct placement of the needle, a contrasting dye can be injected through the needle into the CSF. The dye is taken up by the CSF and confirms proper needle placement.
CT scan also shows if there have been any blood vessels punctured along with the formation of a hematoma (collection or pool of blood). Hematomas must be treated immediately to prevent further complications.