Also known as syringomyelia and hydromyelia are commonly known as syrinx. Essentially, a syrinx is a fluid collection in the spinal cord. There are many causes of this such as hydrocephalus, Chiari Malformation, trauma, tethered spinal cord, tumor and a very large number without any clear cause, the so-called idiopathic. These collections are usually similar to spinal fluid . They can cause symptoms in two main ways. One is due to the direct pressure of the fluid collection on the spinal cord. The symptoms will then be related to the level of the spinal cord at which the collection is. It may cause weakness, numbness, stiffness, pain, scoliosis, and incontinence to name a few. These symptoms usually come on quite gradually.
The other way the symptoms may be found is due to the underlying cause of the syrinx. For instance, a syrinx may be caused by a Chiari Malformation, and the symptom may be one of headaches or neck pain even though the syrinx may be lower in the spinal cord. The important thing is for the physician to recognize the possibilities and perform the appropriate tests.
The availability of MRI has greatly improved our ability to both diagnose and follow these collections. Once one is identified it is usually prudent to study the entire nervous system looking for associated abnormalities which may influence treatment. Once it is determined that the syrinx is of clinical significance (causing problems such injury to the spinal cord or progressive scoliosis) the only treatment available is surgery.
There are many different opinions as to how best treat these collections. In the broadest sense they are as follows. One, if there is an obvious cause (such as hydrocephalus or Chiari Malformation) treat the cause with the expectation that the syrinx will then resolve on its own. Two, treat the syrinx as the initial problem with some form of drain. Three, combine both of these options and treat both the cause and the syrinx at the same operation.
The drains used to treat syrinxes are quite variable. Some surgeons prefer to place a small tube or “stent” in the syrinx. This is a rather short length of hollow tubing that extends from inside the spinal cord collection to just outside the spinal cord where the spinal fluid space is. Others prefer to use a shunt type system similar to that used in hydrocephalus to divert the fluid to other body cavities such as the chest or abdomen.