PEDIATRICS

Procedures

SURGICAL PROCEDURES FOR SPINAL DEFORMITIES

Closure of Myelomeningocele: Closure of the myelomeningocele occurs usually within 24 to 48 hours of the birth of the infant. The infant is almost always delivered by Cesarean section. The closure involves reconstruction of the leather sac that surrounds the spinal cord and holds in the spinal fluid as well as pulling muscle and skin back over into normal position. The bones cannot be replaced.

 

Repair of Lipomyelomeningocele: This involves cutting out or resecting some of the excess fatty growth and then disconnecting the fatty growth in the skin from the spinal cord. An attempt is made to decompress or remove some of the fat inside the spinal cord to allow more room for the spinal cord. The leather sac surrounding the spine (dura) must be repaired at that time as well.

 

Release of a Tethered Cord: The usual procedure for release of a tethered cord involves microsurgically cutting a thickened phylum terminale. This can be done through a relatively small incision. The lipomyelomeningocele and myelomeningocele also cause tethered cord and the tethered cord is released during the usual procedures to repair those congenital anomalies.

 

Resection of Neurenteric Cyst: If a neurenteric cyst causes symptoms it needs to be removed. This is done through a surgery called a laminectomy where a bone on the back of the spine is removed, the leather sac is opened and the cyst is punctured and drained. As much of the walls of the cyst as possible are surgically removed.

Patients who have undergone repair of a myelomeningocele or lipomyelomeningocele can develop scar tissue around the spinal cord that ties down or tethers the spinal cord back to the dura or leather sac and the bones, leading to recurrent symptoms. This is called a recurrent tethered cord. This involves a much more extensive operation to repair.

 

Repair of Arachnoid Cysts: Arachnoid cysts in the spine can be repaired by cutting out or resecting the walls of the cysts or they can be treated by putting a tube into them and by putting the other end of the tube either in the normal spinal fluid or into another cavity such as the pleural or lung cavity or peritoneum or stomach cavity.

 

Treatment of Hydrocephalus: The treatment of hydrocephalus involves placing a tube into the spinal fluid spaces and draining it to another part of the body where it can be absorbed back into the bloodstream. The usual location for placement of the end of the shunt is into a spinal fluid space called the ventricle which is a large spinal fluid-filled space within the brain. There are two latera ventricles, a third ventricle and a fourth ventricle.

Usually the shunt is placed into one of the lateral ventricles. This tubing in the ventricle is connected up to a reservoir or small six to 10 mm button with a rubber covering over it. The reservoir is then connected to a valve which will open and close when the pressure within the spinal fluid spaces reaches a certain level.

The valve is then connected to a catheter that drains into another space where the fluid can be absorbed back into the bloodstream. The most common space the end catheter is placed is the belly cavity or peritoneum. The peritoneum is the cavity in which all of the bowels, gallbladder, kidneys and pancreas exist. The walls of the peritoneum will absorb the spinal fluid back into the bloodstream. This end catheter can also be placed in a vein in the neck that drains into the large veins in the chest (ventriculoperitoneal shunt).

The catheter can then be placed into a large vein in the head which will drain into the large veins in the chest (ventriculoatrial shunt). The end catheter can also be placed into the space between the chest wall and the lungs called the pleural cavity (ventriculopleural shunt) or when the peritoneum does not drain, it can actually be placed into the gallbladder (ventriculogallbladder shunt). Each one of these spaces has the ability to absorb large amounts of fluid back into the bloodstream.

Another place where the spinal fluid can be drained from is the spine in the low back or lumbar area. The shunt can go from the lumbar area to the peritoneum (lumboperitoneal shunt) to the vessels in the chest cavity (lumboatrial shunt) or can go into the pleural cavity (lumbopleural shunt). If the draining end of the shunt is in a cyst in the brain or a spine then it is called a cyst, peritoneal, atrial, pleural, or gallbladder shunt.

All shunts consist of a proximal catheter which is the piece of tubing going into the cavity to be drained, a valve which opens and closes to control the pressure at which the extra spinal fluid is drained, as well as a distal catheter or end catheter which goes into a space where the spinal fluid can be absorbed.

Many times a reservoir is placed to allow sampling of spinal fluid through the skin with a needle. The valve systems can be single pressure or programmable valve. Programmable valves allow adjustment of the pressure through the skin non-invasively using magnets.