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March 30, 2008

BehindTheMedspeak: 'Brain Map Safeguards Speech During Surgery'

Giygigh

William Gibson memorably remarked, "The future is already here — it is just unevenly distributed."

So it is with medicine.

The sophistication — or lack thereof — of a given medical center is extremely variable, even within the U.S.

There are places where you will receive monitoring and interventions unknown to others practicing in the very same field.

Kevin Kelly elaborated on this subject in a recent essay about choosing a doctor.

Today I focus on an innovative approach to the neurosurgical patient employed at M.D. Anderson Cancer Center in Houston, Texas by professor of anesthesiology Dr. David Ferson and his team.

It was the subject of a December, 2006 Anesthesiology News article by Rose Fox, and follows.

    Brain Map Safeguards Speech During Surgery

    Preserving a patient’s ability to speak after brain surgery is a critical concern for surgeons. Even the smallest misstep can cause irreversible damage.

    The challenge is even greater when patients speak several languages. Verbal ability in polyglots seems to be more diffusely scattered across the brain. What appears to be safe tissue in someone’s English region may be vital to her French or German zones.

    “Preserving the eloquent areas is very important in patients with tumors near the areas that produce speech or important motor functions,” said David Ferson, MD, Professor of Anesthesiology and Pain Medicine at M.D. Anderson Cancer Center in Houston. “In the case of someone who is multilingual, it’s important to test them in all the languages they speak, because they [eloquent regions] do not necessarily overlap in the brain.”

    Dr. Ferson and colleagues have developed a “triphasic” method of performing brain surgery with the patient awake, allowing surgeons to observe changes in speech function during the procedure.

    The first phase, in which the skin, bone and dura are opened to expose the brain, is performed while the patient is asleep in a lateral position, with ventilation controlled via a laryngeal mask airway. The scalp and dura are injected with local anesthetic, which is sufficient for pain control during and immediately after surgery. Then the patient is awakened for the second phase, which begins with speech center mapping.

    “We show the patient cards with words or pictures, or ask the patient to perform tasks such as counting or talking to us,” Dr. Ferson explained. “At the same time, the surgeon is stimulating the brain with a small amount of electrical current from an Ojemann cortical stimulator (Integra Lifesciences). If the surgeon touches the area associated with eloquent function, the patient would temporarily not be able to name or recognize the picture on the card. That’s how we find whether the area where we will be performing surgery is functional. This is very important for the surgeon to know, because the speech centers are in a different location in every person.”

    Testing continues during the surgery itself. If the patient shows any deterioration of function, the surgeon can immediately adjust to avoid the functional area. Once the procedure is completed, the patient is sedated for the third phase, in which the dura, bone and scalp are reassembled.

    While treating a trilingual patient who had a small lesion on the left superior temporal gyrus, Dr. Ferson noted that the preoperative functional magnetic resonance imaging (fMRI) had been conducted in English, although the patient considered Italian and Spanish to be her primary languages.

    The fMRI had mapped out a language area that appeared to be a safe distance from the surgical site. During the operation, Dr. Ferson, who speaks four languages, tested the patient in Spanish and Italian and found that those were located at an area that was at risk from the procedure. “If we relied only on the fMRI, then this patient’s primary languages could have been injured if we hadn’t mapped them during the surgery,” he said. The intraoperative mapping helped the surgeon to avoid both eloquent areas while safely removing the lesion. Dr. Ferson and his colleagues recently presented a report of this case at the 2006 annual meeting of the American Society of Anesthesiologists.

    “This is a fascinating demonstration of a phenomenon that we don’t often get to witness,” said Irene Osborn, MD, Director of the Division of Neuroanesthesia at Mount Sinai School of Medicine in New York City. “If a patient is bilingual or trilingual, one should arrange to test them intraoperatively in all their respective languages. It would be interesting to repeat the fMRI postoperatively on this patient to demonstrate the locations of Italian and Spanish languages to see if it correlated with the intraoperative testing.”

    Dr. Ferson and his colleagues have performed more than 350 triphasic procedures, he said, and M.D. Anderson surgeons now rely on the technique in any surgery that threatens the eloquent area.

March 30, 2008 at 02:01 PM | Permalink


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Comments

I've seen one of these procedures up close and personal and it was fascinating. It was also horrifying watching someone with half their head cut off sitting there for a chat!

I have a friend that does this and has to do brain mapping for different purposes, and you can see how a degenerative brain disease kills off certain areas of cognition...let alone surgery doing it all in one swoop.

It is interesting that this is talking about polyglots...I know the one big example we had about these procedures before this was common place was talking about someone that had ended up with a very treatable tumor who had been a POW during WWII. Hadn't spoken anything but English for 30 years...came out of the procedure only able to speak German. Could understand everything in English -- just couldn't speak it!

Posted by: clifyt | Mar 30, 2008 5:04:01 PM

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