فصل 28

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As a chief resident, nearly all responsibility fell on my shoulders, and the opportunities to succeed—or fail—were greater than ever. The pain of failure had led me to understand that technical excellence was a moral requirement. Good intentions were not enough, not when so much depended on my skills, when the difference between tragedy and triumph was defined by one or two millimeters.

One day, Matthew, the little boy with the brain tumor who had charmed the ward a few years back, was readmitted. His hypothalamus had, in fact, been slightly damaged during the operation to remove his tumor; the adorable eight-year-old was now a twelve-year-old monster. He never stopped eating; he threw violent fits. His mother’s arms were scarred with purple scratches. Eventually Matthew was institutionalized: he had become a demon, summoned by one millimeter of damage. For every surgery, a family and a surgeon decide together that the benefits outweigh the risks, but this was still heartbreaking. No one wanted to think about what Matthew would be like as a three-hundred-pound twenty-year-old.

Another day, I placed an electrode nine centimeters deep in a patient’s brain to treat a Parkinson’s tremor. The target was the subthalamic nucleus, a tiny almond-shaped structure deep in the brain. Different parts of it subserve different functions: movement, cognition, emotion. In the operating room, we turned on the current to assess the tremor. With all our eyes on the patient’s left hand, we agreed the tremor looked better.

Then the patient’s voice, confused, rose above our affirmative murmurs: “I feel…overwhelmingly sad.”

“Current off!” I said.

“Oh, now the feeling is going away,” the patient said.

“Let’s recheck the current and impedance, okay? Okay. Current on…”

“No, everything…it just feels…so sad. Just dark and, and…sad.”

“Electrode out!”

We pulled the electrode out and reinserted it, this time two millimeters to the right. The tremor went away. The patient felt, thankfully, fine.

Once, I was doing a late-night case with one of the neurosurgery attendings, a suboccipital craniectomy for a brain-stem malformation. It’s one of the most elegant surgeries, in perhaps the most difficult part of the body—just getting there is tricky, no matter how experienced you are. But that night, I felt fluid: the instruments were like extensions of my fingers; the skin, muscle, and bone seemed to unzip themselves; and there I was, staring at a yellow, glistening bulge, a mass deep in the brain stem. Suddenly, the attending stopped me.

“Paul, what happens if you cut two millimeters deeper right here?” He pointed.

Neuroanatomy slides whirred through my head.

“Double vision?”

“No,” he said. “Locked-in syndrome.” Another two millimeters, and the patient would be completely paralyzed, save for the ability to blink. He didn’t look up from the microscope. “And I know this because the third time I did this operation, that’s exactly what happened.”

Neurosurgery requires a commitment to one’s own excellence and a commitment to another’s identity. The decision to operate at all involves an appraisal of one’s own abilities, as well as a deep sense of who the patient is and what she holds dear. Certain brain areas are considered near-inviolable, like the primary motor cortex, damage to which results in paralysis of affected body parts. But the most sacrosanct regions of the cortex are those that control language. Usually located on the left side, they are called Wernicke’s and Broca’s areas; one is for understanding language and the other for producing it. Damage to Broca’s area results in an inability to speak or write, though the patient can easily understand language. Damage to Wernicke’s area results in an inability to understand language; though the patient can still speak, the language she produces is a stream of unconnected words, phrases, and images, a grammar without semantics. If both areas are damaged, the patient becomes an isolate, something central to her humanity stolen forever. After someone suffers a head trauma or a stroke, the destruction of these areas often restrains the surgeon’s impulse to save a life: What kind of life exists without language?