July 23, 2016
Placement of the External Ventricular Drain is one of the most basic and principle procedures in neurological surgery. This is a 62-year-old male who presented with acute hydrocephalus and obtundation related to a colloid cyst. Patient is in the Supine Position, the head is in an absolutely neutral posture. The head of the bed is elevated at approximately 45 degrees against the surface of the floor. The right frontal area is shaved. The patient is made comfortable. The distance from the tip of my index finger to the root of my thumb is approximately 11 centimeters. I use this method to measure the area and determine the area of the kosher point. The kosher point as you know, it's about 12 centimeters from the mid-pupillary line, and about three centimeters lateral to the midline. Just about a centimeter anterior to the Coronal suture. I usually go about half a centimeter lateral to the kosher point in order to avoid the Parasagittal veins further. Next, this area is well prepped and draped. Again the head is absolutely neutral position so that the anatomical landmarks are preserved. Ample amount of local anesthetic is injected beyond the, area of the insertion of the catheter so that the catheter can be tunneled laterally, after it's inserted into the ventricle. Small stem incision is completed. A handheld drill used. I employ their widest diameter a bit, in order to create the largest Craniostomy, so that the catheter has ample amount of flexible working angles to reach the ventricle. I do not want a small craniostomy to limit my working angles and provide difficulty in reaching the ventricle. Safety stop is also applied to avoid plunging of the drill into the brain. The outer cortex, and it can seal a spoon are drilled into after. I reached significant amount of resistance, which denotes, the fact that the drill has reached the inner cortical bone as you can see here, I used manual rotation of the head of the drill in order to penetrate through the inner cortical bone. This maneuver is quite because I wanna avoid plunging into the brain by the drill. And since ample amount of force is required on the drill to go through the hard inner cortical bone, the manual hand angle of the drill is quite effective in a controlled fashion. You can see the maneuver here. Again, the drill is going through the inner cortical bone as demonstrated here. I often go in and out a couple of times through the inner cortical bones so that, any residual ledge of bone is also drilled away and there's no evidence or resistance or allege of bone that can deflect my catheter into a different location than desired. Blunt instrument is used to penetrate through the dura. The catheter is past perpendicular to the scalp or the skull. That's the method I used for placement of the catheter. Obviously one has to consider the CT findings. If the mass may have distorted the normal anatomical landmarks of the ventricle to other landmarks used by colleagues, one should point a catheter to a plane or at a pathway along the mid pupillary line and above a three centimeter anterior to the external auditory canal. Very importantly, I pass the catheter maximally to the depth of seven to seven and a half 70 meters. If the ventricle is not cannulated at such a length of the catheter, it usually means that the catheter is not advanced at the right angle and further advancement of the catheter more than seven, seven and a half centimeter, at least the catheter to be implanted in a very undesirable location. Here, you can see the five centimeter mark. Here we go, going through the brain, gradually, staying perpendicular to the scalp. It's a five centimeter, six centimeters. Usually one field set pop as the catheter goes through the ependymal You can see clear CSF. The Terrell cries used to tunnel the catheter laterally over the area that was anesthetized at the beginning of the procedure. As the catheter is being tunneled laterally. I try to hold the catheter at the level of the skin to avoid further inadvertent advancement of the catheter. You'll see this maneuver in a moment, here, you can see the four steps holding the catheter. Ultimately, the catheter is connected to additional, pieces that would allow the catheter to be connected to the drainage back. Sutures are used a figure of eight to close the incision. I also use a series of staples, usually three of them to fixate the catheter to the scalp of the patient and avoid it's delayed, Dislodgment. Thank you.
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