Neuroscience Nursing Division
Department of Nursing
The University of Iowa Hospitals and Clinics

Why "stereotactic" surgery?

You are considering or are about to undergo a special brain operation called "stereotaxis." There are a variety of reasons your surgeon may have recommended this type of surgery. Stereotaxis can be used as a type of operation to get a small tissue sample from deep in the brain, where the surgeon cannot otherwise safely do an operation. It may also be used to precisely locate an area to obtain or aspirate a fluid sample for analysis. If the neurosurgeon suspects you may have an infection or abscess, he or she would want this fluid sample to determine what kind of microorganism or "germ" is causing the infection so that you can be started on the correct antibiotic therapy. Still others have this type of operation for the insertion of a special catheter into a tumor to irradiate it from the inside. This is called brachytherapy, and there will be more information about this later.

Advantages

There are advantages in having a stereotactic procedure rather than the typical "craniotomy" operation. There is no risk from general anesthesia since you will not be under anesthetic for the operation. Since you will be awake during the operation, the neurosurgeon can closely monitor your neurologic function throughout the operation. The operation itself is much "smaller," meaning the incision is not as big, and the opening in the skull bone not as large. This operation also allows the surgeon to operate on areas that were considered "inoperable" before this type of surgery was available.

Risks

As with any operation, there are some risks. There is a small possibility of infection. You will be placed on antibiotics to minimize this risk both before and after the operation. You will have a special head dressing over the operation area that has to be kept clean and dry. Another potential complication is that of hemorrhage (bleeding) from the operation, and worsening of your neurologic status. Neurologic status is a term used to describe your level of alertness, and the ability to move and feel your arms and legs. During the operation, the neurosurgeons will ask you to occasionally move your arms and legs, and answer some questions for them so they can assess or monitor your neurologic status. They are generally not able to do this if you are under general anesthesia. Overall, the risks with this type of operation are no different than any other type of brain operation, and the neurosurgeon will actually be better able to monitor your condition during this type of surgery.

Preparation for surgery and ring application

Once you and the neurosurgeon have decided on a stereotaxic procedure, the nurses will help you prepare for the surgery. You will need to have the stereotactic ring applied. This is a black, ring-shaped structure with 4 pins. The neurosurgeon will shave 4 areas approximately 2 inches by 2 inches on your scalp where the pins will be placed. Generally, 2 areas in the temple area, and 2 on the back of your head will be used. Then the areas will be scrubbed with a cold soap to sterilize the area and kill any germs. A special numbing medicine called Lidocaine will then be injected with a small needle into each of the areas to numb them before the pins are inserted. Many people complain of a burning sensation as the Lidocaine is injected. This is usually brief, and is the most uncomfortable part of the procedure for many of the patients.

Once the Lidocaine has taken effect, the neurosurgeon will apply the stereotactic ring. The nurse will help the surgeon position the ring, and tighten the pins. Some patients report that they can't feel anything during this phase, and others feel a slight bit of pressure. If you are experiencing pain, please let the nurse of surgeon know. You may simply need a bit more time for the Lidocaine to work. The ring itself will circle your head about at the level of your nose. It is VERY IMPORTANT that you keep your eyes tightly closed while the neurosurgeon and the nurse are applying the ring. If you are trying to look up at the surgeon while the ring is applied, you may "trap" your forehead muscles above the pins. This could give you a rather "surprised" look since it may pull your eyebrows up, and could potentially cause problems with closing your eyes while the ring is on. If that would happen, the 2 front pins would need to be repositioned. It is generally easier to make sure your eyes are closed the first time around!

Planning CT scan

After the ring is on, a second piece of equipment called a "localizing ring" will be temporarily placed on the ring on your head. You will then go to the radiology area for a CT scan with this second ring in place. During the CT scan, it is very important that you lie absolutely still. The technologists in the CT scanner will probably tape the ring to the CT scanner headpiece as a reminder not to move during the examination. The CT scan with the ring on takes longer than the usual CT scan you may have had before. This is because more pictures are taken during this type of scan.

The localizing ring will be removed after the CT scan is done, but the ring with the pins will remain in place until after the operation. Once the CT scan is done, you may return to your room. The surgeon will take the information from the CT scan with the localizing ring, and feed it into a computer to determine a set of coordinates or numbers that determines where your incision and biopsy will be. With these coordinates, the neurosurgeon will be able to set up some special equipment so that he or she can target the biopsy needle to the exact point it needs to go to get the specimen or implant a catheter. This system is accurate to within 1 millimeter!

The operation

Once the neurosurgeon has all the equipment ready, you will be taken to the operating room. You will need to wear special white elastic stockings called "Teds" to help the circulation in your legs during the operation. You will also get antibiotics just before the operation to help prevent infection. The anesthesiologist will start an IV in your arm if one has not already been started.

Once you are in the operating room, you will be moved over onto a special table. The ring on your head will be attached to the table so that you cannot move it during the operation. This is important because everything has been set up within so many millimeters of measurement, and even slight movement of your head could change all of this. The anesthesiologist will place some electrodes on your chest so that he or she can watch your heartbeat and rhythm during the surgery. They will also place a blood pressure cuff on your arm, and loosely restrain your wrists on the side of the table.

At this point, you will probably receive your first dose of a sedative medication. This will help make you relaxed, and perhaps a bit sleepy.

You will be awake during the operation itself, so that the neurosurgeons can monitor your neurologic status. You will probably hear them talking to you, and with the nurses and anesthesiologist during the operation. Many times the medication has the effect of making you amnesic or not able to remember the operation in clear detail afterwards.

At this point, the neurosurgeons come in and begin their preparations for the surgery. They may look unfamiliar since they will be wearing coverings over their faces and hair. They may also be wearing some strange-looking glasses that help protect their eyes, and help them see during the operation. Your eyes will be covered for the operation to protect them at this point.

The neurosurgeons will shave your head in the area they are going to make the incision. They will them scrub your scalp with the same disinfectant soap they used when the ring was applied. After they are done scrubbing the area, a special drape will be placed over your scalp which will extend down over your face. The neurosurgeons will drape around the area they are going to operate with special sterile towels. This part of the preparations sometimes seems to take longer than the surgery.

A local anesthetic or numbing medicine called Lidocaine will then be injected into the scalp where the incision will be. As previously described, this may cause a burning sensation for a few moments while the medication takes effect.

The incision is then made. Generally, it is about an inch in length. A small piece of bone is then removed using a special drill. You will be hearing the noise the drill makes and may feel a few "vibrations" as the piece of bone is removed. A special ring called an "Arc Ring" is then settled onto the ring already on your head.

The neurosurgeons have preset the biopsy needle in this arc ring using the coordinates obtained from the CT scanner and the computer program. The biopsy is obtained, and sent to the laboratory. Although the brain interprets pain for the rest of the body, it does not sense pain itself, so the biopsy does not cause pain. At this point, the major portion of the operation is over.

It is not necessary to replace the piece of bone since the area missing is so small. You actually do not need to take any special precautions with this area later on once the incision has healed. The scalp is closed with a few stitches over the operation site, and the drapes and eye patches are all removed. The stereotactic ring is also removed at this point. A special head dressing or "turban" is then applied over your entire scalp. Periodically during the operation and immediately after, the neurosurgeons will ask you to answer a few question and to move your arms and legs to assess your neurologic status.

After the operation

After the operation is over, you will be sent to the recovery room for about an hour. The nurses there will continue to assess your neurologic status and vital signs. You will probably get another dose of antibiotics and some medication for brain swelling called Decadron. After your time in the recovery room is over, you will be sent back to the neurosurgical unit.

On the neurosurgical unit the nurses there will continue to check your blood pressure, pulse, breathing and neurologic status every 4 hours for several days depending on your condition. You will usually be asked to sleep with the head of your bed in a slightly upright position to help with swelling after the surgery. You may also be placed on a fluid restriction, which means that you will have a limit on the amount you can drink. Your nurse will explain this to you if the doctors order it. Your nurse will also explain whether or not you can get up and walk around after the surgery. Many times, you will not be allowed out of bed until morning.

You will not be allowed to shower while the head dressing is in place since getting the dressing wet could increase your chance of developing infection. Your nurse will provide you with instructions on how to bathe while the dressing is in place. Your doctor will provide information on when the stitches may come out. Generally, they remain in place for 10 days after the operation before they are removed.

If your operation was to obtain a specimen to identify a tumor, the results may not be available for several days. This time is needed for the pathology doctors to prepare different types of slides to aid in the diagnosis.

If the surgery was to identify a specific type of organism causing infection, the neurosurgeons will have a preliminary report soon after the operation, and a final report in three days. This will enable them to identify the appropriate antibiotics for your treatment.

If your surgery was to implant special catheters for brachytherapy, please continue on to the next section for additional information.

Special considerations with brachytherapy

Brachytherapy is the term used to describe radiation of a tumor from the inside of the tumor. The stereotactic procedure used to place the catheters which will hold the radioactive source or "seeds" into the tumor is the same as was just described. The only difference is that you will have the ring applied and the CT scan the night before the surgery, to give the neurosurgeons and the radiation oncology doctors time to calculate exactly where to place the catheters, and the numbers of seeds needed for treatment.

After the operation to place the catheters is finished, you will return to the neurosurgical unit as described earlier. Later that day or the following day, the radiation oncology doctors will "load" or place the radioactive sources or "seeds" into the special catheters. To accomplish this, they will remove your head dressing, and insert special tubes containing the radioactive seeds inside the catheter tubes placed in the tumor during your operation. Another head dressing is then applied, and you will be taken back for a CT scan to check the placement of the seeds within the tumor. Your doctors will examine this CT scan to check the placement of the seeds within the tumor. Your doctors will examine this CT scan to make sure everything is in exact position. You will not be able to shower while the head dressing is in place since getting the head dressing wet could produce an infection. Check with your nurse for instructions on how to go about bathing in this time period.

The radioactive seeds remain in place for the time period specified by the radiation oncologist. Although the required time varies according to tumor size and shape, most patients will have the seeds in place for 5 to 7 days. While the seeds are in place, you will occupy a private room. A health physicist from the Radiation Protection Office will come to your room periodically to measure the amount of radiation exposure coming from your implant with a special radiation monitoring device. Based on these measurements the health physicist will inform the nursing staff of the necessary precautions your visitors should follow when visiting your room while your implant is in place. In addition, the Radiation Protection Office recommends that pregnant women and children under 18 years of age do not visit patients while the radioactive seeds are in place. Since the radioactive seeds are encased in metal and have been sealed in the catheters, no other special precautions are usually necessary. Your urine, stool and other body fluids do not become radioactive as a result of this treatment.

Nothing that you touch or otherwise come in contact with will become contaminated with radioactivity.

When it is time for the radioactive seeds to be removed, the radiation oncologists will remove your head dressing, and "unload" or remove the seeds sealed in the tube. The health physicists will then perform measurements to make sure that all of the seeds have been removed. Once the seeds are removed, no radioactive material or radiation will remain in your body or room and all radiation precautions are no longer necessary. The neurosurgeons will then remove the catheters that held the seeds and place a stitch or two to close the opening if necessary. These stitches will remain in place for 7 to 10 days. Another head dressing will be applied and left in place for a few days while the incision heals. You need to continue to take care not to get the dressing wet until the nurse or doctor indicates if is safe for you to shower.

If you do not start chemotherapy or radiation for a few days, you may be able to return home at this time. Again, your doctor will be able to advise you on this. Your physician or nurse will provide you with instructions about when the stitches need to be removed when you are discharged. Generally, you will either report to the neurosurgery clinic for stitch removal, or have your local doctor take the stitches out. At the time of discharge you will also receive information about your return clinic appointment and CT scans for medical follow-up.