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Mapping the brain - the triumph of a simple idea
2nd July 2015; 11:10 am: Finally, the day of surgery has arrived. Reiner Hesse is being wheeled into the operating theater. For weeks now, he has been longing for something that not many people would wish for – undergoing open brain surgery, while being awake and aware for every single second of it.
Reiner Hesse, who is 59 years old and enjoying early retirement, has known about the tumor inside his head for six whole weeks. Initially, he noticed he was rapidly losing weight, 13 kg within a matter of months. Then, more and more often he finds himself unable to think of even simple words. An MRI scan results in a diagnosis - and an unwelcome prognosis: the tumor is located near the speech center of the brain – and permanent damage cannot be ruled out.
Reiner Hesse has plenty of experience as a patient of Charité. Only four years ago, and after seven years on dialysis, he finally underwent a successful kidney transplant. Since then, he has been visiting Charité several times a year for follow-up appointments. It seem only natural that he should turn to 'his' hospital for help once more. If anyone can help him, it is the physicians at Charité; of that Reiner Hesse is certain.
12:19 pm: in the meantime, the entire surgical table has been covered with blue surgical drapes. Only the patient's head is still visible. He is not moving and has been placed in what appears to be a type of clamp. Next to it is Dr. Katharina Faust, a Senior Physician at the Department of Neurosurgery. At 35 years of age, Dr Faust has extensive experience of awake brain surgery (intra-operative brain mapping). She asks the patient if he is lying comfortably, and compliments him on breathing calmly and regularly. Then follows a gentle warning: “It's going to get a little noisy now, Herr Hesse. We have given you a local anesthetic, though. You won't feel a thing.” The physician then switches on the special bone saw. At 12:23 pm, the brain is exposed, visibly pulsing and surrounded by fluid. Katharina Faust asks for the microscope to be brought closer. Three separate monitors show the surgical field, magnified 40 times, allowing everyone in the room to follow every detail of what she is doing. She says: “Herr Hesse can wake up now.” This means the difficult part begins.
Every year, the Department of Neurosurgery performs approximately 500 brain surgeries. In a quarter of cases, there is a risk of the patient's speech or movement being impaired. “In the past, we used to have just seconds to decide whether to remove a tumor, even when there was a risk of the patient losing the ability to speak or walk,” explains Dr. Thomas Picht, Faust's predecessor at the Department. It is thanks to him that this way of doing things has been safely consigned to the past. “It just suddenly occurred to me while I was at a conference ten years ago,” remembers Dr Picht, “wouldn't it be possible to combine MRI imaging of the brain with magnetic stimulation, thereby allowing the surgeon to determine, without having to open the skull, where exactly in the patient's brain the centers responsible for speech or movement are located?”
Even the very first attempts, which he carried out together with his colleagues at the Department of Neurology on Campus Charité Mitte, were successful: magnetic stimulation, an established diagnostic technique in the field of neurology, is used in patients with epilepsy and pain syndromes, allowing active areas of the brain to be mapped. The MRI visualizes the areas of the brain currently activated, making it possible to gradually build a map of the brain. While this may sound as simple as it is fascinating, the truth of the matter is that, before Dr. Picht, nobody in the entire world had come up with this idea. Although Dr. Picht succeeded in arousing the interest of a medical devices manufacturer back in 2007, the newly-developed technique was initially only used at Charité. The method has been proven to be effective. Ever since neurosurgeons started using Picht's method of navigated transcranial stimulation (nTMS), the number of cases of permanent paralysis following brain surgery has been reduced to less than half the previous figure. Even tumors located close to the brain's speech center can often be removed completely, thereby significantly improving the patients' chances of survival.
So far, more than 500 patients have been treated at Charité using nTMS. No longer in its infancy, the technique is now being used in 15 neurosurgical departments in Germany, and has received a lot of interest from the U.S.A., Japan and Russia. Picht does not appear to realize the full impact and significance of what he developed. A patent? It never occurred to him, reports the somewhat boyish-looking physician. After all, nTMS is no more than the further refinement of existing techniques. Picht appears far more interested in his children. They are the reason behind his decision to give up his position as Senior Physician and why he chose to lead on a number of research projects at Charité instead. He confirms that “this move into research was a risk,” but adds that “it was exactly the right decision to make.”
Reiner Hesse remains completely oblivious of it all. He just finds it a little strange to be asked to sit on a chair a few days before the scheduled operation and be asked to explain various images with various cables attached to his head. Katharina Faust shows him the results of this test on the screen. “Do you see these green strands? That is your speech center. The red area behind it is the tumor. I think we will be get to it fine.” Later, she explains that there simply is no absolute certainty when dealing with the speech center. While nTMS makes it possible to map the surface of the brain, it does not allow mapping of the inside of the brain, where some of the patient's speech functions may be located.
This is why Dr. Faust repeats the procedure once she has exposed the brain. She uses an electronic probe to systematically feel her way around the surgical field while Hesse describes the images shown to him on a monitor by one of Dr. Faust's colleagues. “A tree, a horse.” Gradually, the pulsing brain is covered in tiny sterile paper strips. Each of them is marked with the number '0', indicating that there are "no functions" here – i.e. it is OK to cut in this area. Which is exactly what Dr. Faust does. She systematically works her way around the gelatinous mass, removing white-colored patches – the tumor. All the while, Hesse is engaged in an animated conversation with one of her colleagues. Faust joins the conversation and asks “What is your sister's name, by the way?” “You mean the short, plump one?” comes the patient's rather ungallant reply.
1:30 pm: Half-way through! The theater nurse places a section of the tumor into a test tube. A special bicycle courier will take it to the Institute of Neuropathology on Campus Charité Mitte, where it will undergo immediate examination. Half an hour later, Faust will know the type of tumor she and her patient are dealing with.
1:53 pm: Suddenly, there is a little scream from Reiner Hesse. The doctor hurt him, he complains. His speech sounds labored, he is struggling to find the right words. “Oh, I think we have overdone it and vexed your brain,” says Faust. She apologizes to Hesse, and moves on to a different section of the surgical field. Only five minutes later, her scalpel moves back to the same sensitive area. “There is a bit of the tumor left here,” she explains. “But we're nearly done.”
2:10 PM: Katharina Faust closes the wound. “We were able to completely remove the tumor,” she says to her patient, who is back under sedation. “You may find you will have some problems speaking for a few weeks. But I am absolutely certain – your brain will recover completely.”
Three days later: A beaming Reiner Hesse meets us at the door to his room. “I feel great,” he announces. “And the operation was incredibly interesting.” As it turns out, his tumor was a lymphoma. Hesse will have to undergo a course of chemotherapy. With this type of tumor, chemotherapy significantly increases the patient's chances of recovery. His optimism, however, is undaunted, as is his eagerness to learn about all things medical. Reiner Hesse has already decided on the first book he will read while he is recovering. The book's title is Darm mit Charme (Charming Bowels). And the author? A physician, of course.
(* The patient's name has been changed)