The posterior cervical foramenotomy procedure that is designed to remove a herniated disc from the rear of the neck (the cervical spine). There are significant restrictions regarding this procedure as it has a limited usefulness.
A patient needs to have a good understanding of the anatomy of the neck to understand when this procedure is useful. The hole that the neck nerve exits out of is called the foramen. The foramen has a front wall, two side walls and a back wall. The front wall is made up of the disc and uncovertebral joint (please see section on anatomy for further explanation). The two side walls are the pedicle above and below. The rear wall is the facet. Of course, the facet is made of two joining bony surfaces, the superior and inferior facet from the vertebra above and below.
The posterior cervical foramenotomy name nicely describes what the surgery entails. The surgery is performed from the back of the neck (posterior cervical) and the foramen is partially removed (foramenotomy). If the procedure was called a foramenectomy, the entire foramen would be removed (ectomy vs. otomy).
The facet is obviously where the approach to this surgery is made as it is the back wall of the foramen and the surface that presents during posterior surgery. A small incision is made in the back of the neck at the level of the herniation. After the incision is made, a small tube can be placed to operate through or a small retractor can be used to expose the facet.
Using a small burr, a portion of the inside of the facet is removed- normally about one-half of the facet. This exposes the back of the nerve root and the blood vessels in the foramen. Using small instruments, the nerve is gently moved up or down to free up the herniated disc fragments. Once removed, the procedure is over and the incision is closed.
There are two versions of patient positioning during surgery that deserve attention. The blood vessels that surround the nerve root can bleed significantly and obscure the view of the nerve and disc herniation during surgery. If the patient is positioned face down on the table, blood pooling can make the surgery more difficult as gravity holds the blood in the incision. Some surgeons will actually sit the patient up after anesthesia is induced before the incision is made. This has two beneficial effects. Gravity will cause the blood vessels in the neck to be less dilated and therefore less bleeding is noted. Also, blood will run out of the incision instead of pooling which makes visualization easier. The drawback of sitting the patient up is that tongs have to be inserted into the bone of the skull to stabilize the patient during this procedure.
Restrictions to this procedure are that the nerve has to be compressed strictly by a herniated disc fragment and not by a bone spur. The disc fragment can be removed safely but a bone spur from the uncovertebral joint cannot be removed by this procedure. In addition, if the disc fragment originates from underneath the spinal cord, this procedure should not be used as manipulation of the cord to retrieve the fragments is not advised.
There are two consequences from the herniation that need to be understood. Remember that the disc has a through and through tear in the annulus that allowed the herniation to occur in the first place. Since the disc has no blood supply, the hole in the disc wall is permanent. The chance of a recurrent herniation from the same hole in the disc wall exists. Also some of the shock absorption of this disc is lost. A portion of the facet has to be removed to perform the surgery. Adding together the loss of shock absorption and the missing portion of the facet, the mechanical integrity of this motion segment is somewhat compromised. Neck pain can result. If it does occur, normally it is mild but some cases can be significant enough to result in the need for an ACDF surgical procedure at a later point (anterior cervical decompression and fusion).
To learn more about posterior cervical foramenotomy as a treatment option for spine related conditions, please contact Dr. Donald Corenman at his Vail, Colorado office at 970-479-5895.