A spinal shunt (also known as a lumbar shunt) is designed to bypass, or redirect, bodily fluids from one point in the body to another. Two types of lumbar shunts include Lumbar-peritoneal (LP) and Lumbar-subcutaneous (LS), although the LP shunt is most common.
Both types of spinal shunts are composed of tubing or a catheter and some variations include a valve for fluid output monitoring. The choice in shunt used is most often based on the patient and how well they will progress with the device and whether shunt revisions in the future are expected or indicated.
Insertion of an Lumbar-Peritoneal Shunt
The lumbar-peritoneal shunt in inserted between two of the vertebrae in the lumbar portion of the spine into the cavity surrounding the spinal cord. This cavity, also called subarachnoid space, is filled with cerebrospinal fluid (CSF). The insertion of an LP shunt is usually indicated when the amount of CSF fluid in the subarachnoid space is more than usually desired. The other end of the shunt tubing or catheter is routed into the peritoneal cavity, an area in the abdomen and drains the excess CSF fluid here. The excess fluid is eventually absorbed by the organs and passed out through the body during urination. Patients usually have two incisions, one in the lower spine and one in the abdomen, each no more than an inch in length.
Most LP shunts remain in a patient's body forever unless revisions or relocation is required. It is difficult to remove a patient's lumbar shunt because determining if their condition has improved because of the shunt or improved despite the shunt is almost impossible. Most neurosurgeons prefer to leave the shunt inserted instead of having to undergo another procedure later to re-insert the shunt if the patients excess CSF reoccurs.
Spinal Shunt Revision Surgery
A spinal shunt revision surgery involves completely replacing a shunt or making adjustments to all or part of the current shunt. For some patients, depending on their reason for having a shunt, multiple revisions may be required and expected from the start. Revisions can be as simple as adjusting the setting on a valve to change the flow or something more substantial like replacing a portion of the shunt with new material.
Spinal shunt revision surgeries are usually the cause of the following complications:
- over drainage
- under drainage
- blockage or obstruction