A Messy Art

A few months ago, I sifted through a stack of junk mail on my desk–“Neurosurgery Opportunity in North Dakota,” “Advances in Acromegaly,” “Katrina, Join Us in New Orleans!”–and tossed most of it. At the bottom of the pile was a big, floppy, colorful 2008 calendar from medical-device maker Medtronic. This I lingered over for a moment, then saved.

Medtronic’s navigation business, which creates technology that helps surgeons explore the human body, is headquartered at the foot of the Rocky Mountains. The calendar promised “stunning imagery from Colorado and stunning innovation from Medtronic.” Take September, which features an “autumnal sunset in a thriving aspen forest near Durango, Colorado.” This image is paired with a photograph of a piece of surgical technology that gets its own loving description: “Medtronic cranial navigation pointer probes provide an enhanced patient registration experience for a thriving neuronavigation practice.” I see the connection: thriving forest, thriving practice. I’ll take one of those pointer probes, please.

Where to hang this calendar, though? September might provide a pleasant piece of art for my office, but August, which features a blurry and bloody close-up of what I believe is probably a brain tumor as seen through a surgical microscope, might be pushing it. (“Doc, that calendar over there: what exactly … ?”) I figured that my kitchen was out, too.

There was a time when displaying such images made perfect sense to me. Years ago, thrilled to have been accepted to a neurosurgery residency program, I contacted a medical-device manufacturer to get my hands on a poster featuring detailed photos of aneurysm clips, which are used to close off a bulging area in a weakened arterial wall to prevent a hemorrhage in the brain. I had seen such a poster once before and was amazed by the clips’ variety of configurations and sizes. These small titanium devices are gems of form and function, perfectly engineered for their specialized task. Having finished medical school, I was about to embark on the seven-year training required to become a neurosurgeon. I wanted that poster.

I am surely not alone in loving the tools of my trade, nor in finding them physically exquisite. Surgeons are the natural technophiles of medicine, and neurosurgeons rely at least in part on especially advanced technologies. But there is a flip side to the wonder I feel, and it is this: each new technological advance promises a fresh cause for cursing in the operating room. Although the details change from decade to decade, and even from year to year, the source of consternation remains constant: the fiddle factor. It is, in essence, the same problem that arises with laptops, cell phones, digital cameras, and home theater equipment. When the ­complexity of your home theater system gets the better of you, though, it just means that you might not get to enjoy tonight’s basketball game in surround sound. In my job, the fiddle factor can have more serious consequences. This, after all, is brain surgery.

Measure Twice, Cut Once
My profession has come a long way since the dark early days of exploratory surgery. Before the advent of computed tomography (CT) in the 1970s, a surgeon was often guided by clinical judgments about as vague as “It’s got to be on the left side.” Things got even better in the 1980s, with advances in magnetic resonance imaging (MRI). And in the decades since, neurosurgeons’ ability to target a lesion, such as a tumor–to figure out where it is in the brain, and then to actually find it at the time of surgery–has been aided dramatically by advanced imaging and the technology it has made possible.

The technology that always seems to impress visitors to our operating rooms is our navigation equipment. (“Navigation” sounds better than “computerized frameless stereotaxy,” so I will stick with that term.) Simply put, navigation technology affords us something like x-ray vision during surgery. With a specialized wand (or “pointer probe,” our Miss September), we can point to a specific location on or in a patient’s head, and the system will show us–we hope–the corresponding spot on a previously obtained MRI of the patient’s brain. It works well most of the time, but like almost every other technology we surgeons use, it has a few kinks and causes a few headaches.

Most brain trauma cases don’t require the navigation technology, for three reasons. First of all, if the case is urgent, we don’t have time to set up the equipment and do the necessary scanning. Second, what we’re after is usually large and can’t be missed, like a big blood clot. Third, in trauma cases we’re less concerned about the niceties that navigation helps us provide, such as a minimal hair shave and a minimal incision.

A small tumor, on the other hand, is a perfect situation for navigation. I’ll walk you through a sample case, altering (in the interest of patient privacy) a few unimportant details.

The patient is a 62-year-old woman who has had a seizure, the first of her life. Upon visiting the hospital, she undergoes a brain MRI, which picks up a round, two-centimeter tumor in her left frontal lobe. She has been a smoker since age 20. She has no previous history of cancer.

In a long-term smoker, a small, round tumor in the brain certainly doesn’t look good, but we always hedge our bets: “We won’t know what it is for sure until we actually get a piece of it.” In our line of work, it’s not unusual to see a diagnosis of lung cancer made only after the disease has metastasized to the brain. The parent tumor may have lurked silently within the lung for years.

The decision for surgery is made by the patient, her oncologist, and me. Such decisions take many variables into account, but suffice it to say that medicine is often equal parts science and art. As is often the case in neurosurgery, the best treatment is not entirely obvious. Something has to be done, but that something doesn’t necessarily need to be surgery: the patient could choose the noninvasive option of stereotactic radiosurgery, a focused form of radiation that can control or shrink (but not necessarily get rid of) a tumor in the brain. This woman’s oncologist, however, strongly favors surgery. So now the patient is about to go under the knife. I spend plenty of time with her and her family, preparing them for the experience.

Just before surgery, my patient is required to undergo a second MRI (“You want me to get another one of those?” she asks me), this time with several fiducial markers (small, round foam stickers with holes in their centers) applied to her head to serve as reference points. This particular MRI is sliced even finer than her original one, and the images will be downloaded into our navigation equipment. We’re aiming for millimeter-scale accuracy.

Next, in the operating room, while waiting for the patient to be put under general anesthesia and “lined up” (fitted with various catheters, or lines), I speak with the circulating OR nurse and my physician assistant about the navigation setup. (Given that we’ll use a lot of bulky equipment, we give thanks if we’re in one of the larger operating rooms.) Where will the head of the bed be? Did the disc with the patient’s MRI actually make it up from radiology? Where do we position the monitor? What about the camera that tracks the location of the pointer probe? We don’t want to move any major navigation equipment to the other side of the room once everything is already plugged in; that, we worry, could trigger a full-scale meltdown. In reality, though, I believe the occasional meltdown occurs randomly, just because the system is so complex.

Registration first requires immobilizing the patient’s head in a three-point-fixation device that resembles a vice or ancient torture clamp. This part almost always makes a visitor squirm, and I agree it does seem brutal, but it’s crucial. If the head moves even a little bit during the operation, all bets are off in terms of navigation accuracy. (I was impressed once when I saw doctors on Grey’s Anatomy using what appeared to be an authentic, properly set up navigation system in a brain-tumor operation; but then I noticed that the patient’s head wasn’t stabilized in a clamp.) In some cases, an unsettling head wiggle can be detected partway through the surgery, and it’s up to a nonsterile person in the room to peek under the sterile drapes and do some investigating while the surgeon pauses and feigns patience. Where is that damn wiggle coming from? The bed? One of the joints of the clamp? In an operation without navigation, we’ll tolerate a little wiggle. In an operation with navigation, we can’t afford to.

Once the head is immobilized, the surgeon touches the fine tip of the wand to the center of each fiducial marker and depresses a foot pedal. This correlates the location of the wand’s tip with the image of the fiducial on the patient’s MRI. One of many problems here is that five shiny metal balls attached to the butt of the wand must be visible to the large camera in the room in order for the system to accurately register the wand’s location. Depending upon the patient’s positioning, sometimes the camera can’t see all the balls when the tip of the wand is at the center of a fiducial. We try to place the fiducials so that the balls won’t end up hidden by a particular turn of the head, but we’re not perfect.

Another source of fiddle factor is that certain parts of the scalp are mobile: consider how a sticker on your forehead moves if you wrinkle your brow. So the registered position of a given fiducial in the OR may be slightly different from the position recorded in the MRI scanner. Fiducials attached to the fixed bony prominence just behind the ear tend not to move as much–but they’re particularly likely to be hidden from the camera if a patient’s head is rotated. You can’t win.

In a newer method of navigation registration, a handheld scanning device is moved slowly over the patient’s face to register dozens of points along its topography, doing away with the fiducials altogether. But this system has its own kinks; for example, the tip of a patient’s nose is sometimes “cut off” by the MRI scan. I’ve tried this scanning device but have not been able to get it to work well. Maybe I’ll try it again at some point. But then I’d have to deal with the headache of using an unfamiliar technique.

Let’s get back to our patient. We are able to capture eight of the ten fiducials, with an overall margin of error of 1.4 millimeters. Decent. I do a crude check of the system by placing the tip of the wand at the top of the bridge of the patient’s nose, right in the center. I look up at the monitor, which displays the patient’s MRI in three planes. The position of the dot on the images–representing the tip of my wand–assures me that the system can tell where I am. I do a similar check with the inner and outer corners of both eyes. Perfect.

Next is the fun part. Before the operation begins, before I even shave a path for the incision and prepare the head with an antibiotic solution, I test my own visual-spatial skills. Where do I think the tumor is? I know it’s in a certain region of the left frontal lobe, but here’s why this exercise is a bit of a challenge: the frontal lobe is large (the largest lobe of the brain), the tumor is small, and the head is round. I point to where I think the tumor is, mark the scalp with a surgical marker, and then reach for the wand. I run its tip around in the general vicinity of my mark and watch the corresponding MRI images as they appear on the screen. The images continually shift as I move the wand. When I reach the point that lies right above the middle of the tumor, I freeze my position. My original guess was about two centimeters off: not terrible, but certainly not dead on.

Before the arrival of user-friendly navigation technology in the 1990s, neurosurgeons often had to shave a large amount of hair, create a generous incision, and remove a relatively large disc of skull, just to be certain that they got the whole tumor. Now that we can pinpoint exactly where a tumor is ahead of time, that’s no longer necessary. My patient’s hair is long, so I anticipate that at the end of the case I will be able to flop it over to conceal the incision. Some patients get radical haircuts just before surgery (and some men decide to shave their heads), assuming that this will facilitate the operation or the healing in some way. But I find it’s actually better to keep the hair long: I believe that looking less like a patient can speed recovery.

When I remove the portion of skull overlying the woman’s small tumor, the brain appears perfectly normal. I expected this. Her tumor is not on the surface of the brain but about a centimeter below. This is where navigation makes a big difference: I know exactly where to enter the brain in order to reach the tumor. As a rule of thumb, we try to violate as little brain tissue as possible. There’s no way to avoid disturbing some of it, but you want to avoid excessive fishing around.

Before navigation came onto the scene, ultrasound was used more routinely for this purpose than it is today. Ultrasound, though, presents problems: a skilled technician (or an actual ultrasound radiologist) must often be in the room to help interpret the grainy images, and ultrasound has trouble pene­trating bone, so it can’t help the surgeon plan the incision or the bone opening. Besides, it’s clunky. Picture the setup used for prenatal ultrasounds, and now picture it being used on an exposed portion of someone’s brain. What’s more, you can’t actually squirt gel on the brain as you would on a woman’s belly, so a nonsterile person in the room applies the nonsterile gel to the ultrasound probe. Then the probe (plus the gel, plus the long cord) is carefully sheathed in a sterile plastic covering. This technophile finds the whole thing quite inelegant. I have actually resorted to using ultrasound a couple of times when the navigation system either broke down or was rendered inaccurate, and those operations felt very retro.

After opening the skull, I enter the cortex of my patient’s left frontal lobe. I dissect through the white matter to a depth of about one centimeter, and I hit tissue that is firmer and darker than white matter. This is clearly the tumor. I take a small piece of it and have it sent off to the pathologist, who looks at the tissue under a microscope and calls in to the OR to confirm my suspicion of a metastasis.

Considering the flashiness of our navigation systems (which have cool trade names like StealthStation and ­BrainLab), the reader might be eager to discover what technology we use to actually remove the tumor. I’m sorry to disappoint, but the answer is a lowly metal suction tube in one hand, paired with a simple cautery device in the other. But that’s modern surgery: part high tech, part seriously low tech.

These old-fashioned but reliable tools come with their own set of headaches, of course, as when the suction tubing gets clogged again and again or the cautery tips become caked with charred tissue and have to be wiped clean over and over, like a toddler’s runny nose. I do have access to an ultrasonic aspirator, if I want it, but it’s not worth bringing in another bulky item for such a small tumor.

But though navigation can be a big help in tumor resection, it’s not without its difficulties. Sometimes a new nurse or resident forgets that the camera needs an unbroken sight line to the wand and keeps sticking a head or an arm in the way, or a small spot of blood on one of the wand’s shiny metal balls temporarily prevents the system from working. And those technological woes are nothing compared with the physio­logical problem of brain shift. Once the skull is opened, its contents can move a little: sometimes cerebrospinal fluid leaks out, causing the brain to sink downward; other times, the swollen brain bulges outward; and as more tumor tissue is removed, the surrounding brain can partially collapse into the cavity. Whatever the reason, the result is that after all the care we took in registration, the MRI images no longer match up with the patient’s brain. This may not significantly affect the operation, but in some cases it’s such a serious challenge that the surgeon must abandon the navigation technology altogether and rely on her own judgment.

Following the tumor resection, I spend the next several minutes making sure there’s no ongoing bleeding. Then I close, which requires replacing the bone flap by affixing it to the skull with thin titanium plates and screws. Placing tiny screws into the skull presents its own set of problems–admittedly minor, but disproportionately annoying at the end of the operation. Sometimes a screw fails to gain adequate purchase in the bone and continues to spin freely with each twist of the wrist; or it falls off the diminutive screwdriver and gets lost in the folds of the sterile drapes; or it breaks through a very thin portion of the skull, threatening to irritate the tissue underneath. At this point, though, any expletives uttered by the surgeon are drowned out. With the more delicate parts of the operation behind us, “closing music” plays at high volume.

The two final steps of the operation–sewing the scalp closed and placing the surgical dressing–are refreshingly simple, low tech, and fiddle free. I remove my patient’s head from the clamp, watch her wake up, and turn down the music.

New and Improved
Neurosurgery is an unusual specialty, in part because it encompasses such a broad range of operations. Cardiac surgery (in adults, at least) revolves largely around just two major procedures: bypass surgery and valve surgery. Neurosurgery, in contrast, covers operations on the brain, spine, peripheral nerves, and carotid arteries. And particularly within the categories of brain and spine operations, there are dozens of variations. Any one neurosurgeon, although he or she may have been trained to perform the entire spectrum of procedures, cannot actually do so in practice. So how do we neurosurgeons decide which cases to include or exclude? How do we decide which particular disorders to treat?

One big factor in the decision is the technology used to treat a given disorder. That may sound a bit backwards. Wouldn’t a physician’s decision about which cases to treat be based on more profound factors, like a passion to help those afflicted with a particular disease? In reality, though, technologic considerations may trump intellectual or emotional ones.

On the other hand, other neurosurgeons hate this sort of work. They prefer the bigger cases that involve wider exposure of the brain and more hands-on manipulation of the anatomy. They might even call their differently minded colleagues “needle jockeys.”

But there’s one thing most neurosurgeons agree on, and that is the seemingly simple operation we call the VP shunt. “VP” stands for ventriculoperitoneal. In essence, the shunt is a long, thin tube that runs from the fluid-filled cavities in the brain (the ventricles) to the belly; it’s designed to drain the excess cerebrospinal fluid that characterizes hydrocephalus. Pediatric neurosurgeons can’t get away from this operation, because it’s their bread and butter. Childhood hydrocephalus is one of the most common disorders they treat, and the VP shunt is a lifesaver.

Many neurosurgeons, however, shy away from the adult-onset form of hydrocephalus called normal-pressure hydrocephalus (NPH), which is often misdiagnosed as Alzheimer’s disease. As is often the case in medicine, we don’t understand much about this disease, but we know how to treat it. Placement of a shunt can relieve its symptoms, which include poor balance and a shuffling gait, memory loss, and incontinence.

You might think that NPH would be a favorite among neuro­surgeons. After all, treating it has the potential to be quite rewarding. I have seen some patients improve so dramati­cally that their families say a miracle must have occurred.

Still, surgeons often joke that shunt work is akin to plumbing. But I can’t imagine that plumbers encounter quite as much trouble. One strike against the operation is economic: ­Medicare reimburses the surgeon less than $1,000, a fee that covers all follow-up in the hospital and three months’ worth of office visits. Financial considerations aside, what irks so many neurosurgeons about the VP shunt is its fiddle factor.

NPH can be unpredictable. In some patients, one or two symptoms improve when the shunt is installed but another doesn’t. What’s more, the symptoms have a way of creeping back for no apparent reason, even after an initially successful operation. This is frustrating for the patient, the family, and the surgeon. It leads to a series of questions: Did the shunt stop working? Is the tubing clogged? Are we dealing with more than one disease? To answer these questions, how much of a workup are we going to do? Should we get x-rays of the shunt and a CT scan of the head? What about tapping the shunt by putting a needle into it to see whether fluid can be withdrawn (which reveals whether the tubing is blocked but risks introducing an infection)? Then there are the other vague symptoms that tend to crop up in older patients: dizziness, fatigue, headache, abdominal discomfort. When such symptoms arise, the shunt is inevitably called into question.

These frustrations are here to stay, but surgeons continue to hope that the newest iteration of the VP shunt will at least ease the technological hassles. In my experience, though, what often happens is that new ones replace the old.

Programmable valves largely did away with those return trips to the OR: the pressure setting of the valve can be changed in the office, noninvasively and painlessly, with a magnetic device. But that process introduces a fiddle factor of its own. For one thing, the setting can be tweaked almost endlessly, in 10-millimeter increments. Deciding when, how often, and how much to change a shunt setting is a messy art. Overdrainage can make fluid pressure drop too low, causing headaches; underdrainage can leave the original symptoms poorly controlled. Sometimes the surgeon never quite finds a patient’s sweet spot. Some patients return to the office over and over again, hoping to find relief for every symptom, even unrelated ones. And sometimes the family disagrees with the patient; then the surgeon has to pick which party to please.

That’s not the only problem with programmable valves. In at least one popular brand of shunt, the powerful magnetic force of an MRI scan can change the valve’s pressure setting inadvertently. (This was not a problem with the traditional, nonprogrammable shunts.) And these days, MRI scans are ordered at the drop of a hat. Let’s say that a patient with a programmable shunt develops a hip problem, and her orthopedic surgeon orders an MRI. There are a couple of potential pitfalls here. One is that the patient (especially an NPH patient with memory problems) may forget to tell her neurosurgeon about the scan. Furthermore, the radiologist may not realize that the shunt is programmable or that an MRI can change the setting. I have seen patients whose settings had been off-kilter for more than a year following an MRI scan.

Ideally, when a patient with a programmable shunt susceptible to this problem undergoes an MRI scan, imaging of the shunt valve is ordered for the same day, so that the valve’s setting can be confirmed. These images then have to be read by a radiologist or neurosurgeon who is familiar with that particular shunt. If the setting is off, then the neurosurgeon needs to reset the valve and perhaps even send the patient back for repeat imaging.

A more advanced programmer uses a built-in ultrasound to confirm a valve’s setting without requiring separate imaging. But this introduces two new problems. The first is that some patients complain about getting ultrasound gel on their heads and hair. Second, the programmer is so sensitive and temperamental that it may not work in rooms with either too much noise or too much electrical equipment. This pretty much describes most doctors’ offices. In my first experience with the new programmer, I tried close to a dozen times to adjust the valve setting before I gave up, used the old programmer, and sent the patient off for fluoroscopic imaging.

Meanwhile, a competing manufacturer has designed an altogether different programmable shunt that is advertised as MRI compatible. Not only that, but its programmer is almost pocket-sized, whereas the programmer for the old shunt is housed in a heavy, unwieldy, briefcase-like container. When I heard about this new shunt, I jumped at the opportunity to try it. It seemed almost too good to be true: no need to worry that MRI scans would change the settings, no need to bother with fluoroscopy, and no need to lug a heavy programmer. My first few cases with the new shunt went fine from the surgical standpoint. But it turned out that despite what I had been led to believe, MRI compatibility cannot be guaranteed. As I learned from a representative of the company that made the competing shunt I’d just forsaken, the fine print reveals that follow-up imaging of the new valve after an MRI is still officially recommended. Conclusion? Again, I can’t win.

A young surgeon relishes such tangly cases–tough, complex, time-consuming, high-tech. While the operation is in progress, the room might be crammed with people–two surgeons plus a surgical assistant, two or three nurses, one anesthesiologist, one or two neuromonitoring technicians (who usually sit quietly in a corner), a “cell-saver” technician (to run the machine that cleans and recirculates lost blood), one or two industry reps who stand back and field questions from staff about their equipment, and perhaps a radiology technician if fluoroscopy is being performed. The size of the crowd can be almost comical. More and more trays of surgical instruments are brought in as the surgeon encounters tricky conditions or unusual anatomy.

I’ve found, though, that as surgeons get older, they appreciate the simpler cases more and more. Some of the happiest senior surgeons I know have reduced their practices to just a few nice cases–the ones that require the least support staff, the least technology, and the least clutter in the operating room. The other day, while I was doing a quick carpal-tunnel operation using only a few simple instruments, I had two thoughts. The first was that this procedure is one of my favorites. The second was that I must be getting old.

When I was a resident, one of my attending surgeons was revered for his minimalist style and slick surgical skills. His description of his method was something like this: “I like to pare down an operation to its essentials. I cut out one small, unnecessary step at a time. If I detect any problems, then I add a step back in.” This may sound scary, until you realize that fiddling with extra steps can cause problems. Extra steps–extra instruments and maneuvers–can mean more time under anesthesia and a greater chance of infection.

Why do these extra steps exist in the first place? Sometimes a little detail here or there is more voodoo than common sense, but we keep up the tradition because that’s what we were taught. Perhaps we don’t question the standard procedures enough. Do we really need to leave a drain behind? Do we really need to close that layer in a careful, watertight fashion? Does it actually help to inject a numbing medication into the muscle before closing? Is smearing antibiotic ointment over a clean incision really necessary?

On the other hand, sometimes technological innovation adds details to an operation that may not benefit from them. Don’t get me wrong: I am more enthusiast than Luddite. But sometimes what I observe is a new technology searching for a need instead of filling one. In that case, beware.

For example, a common buzzword in surgery is “minimally invasive.” An entire industry’s worth of scopes, retractors, and instruments have been developed so that practically any operation can be done in a way that meets that description. In general, I welcome the trend. Who would choose to have an open gallbladder operation instead of leaving the hospital with just a few small stab marks?

In the case of gallbladder surgery, the benefit of minimally invasive laparoscopic techniques over open surgery became so obvious over time that a randomized, controlled trial–another buzzword in medicine–was never even undertaken. And within neurosurgery, the minimally invasive approach to certain major spine fusions is a godsend to the patient. The advantages over traditional, open surgery are numerous: a much smaller incision, less surgical trauma to the muscles, less pain, fewer narcotics, and a shorter recovery.

The senior surgeon who taught me the traditional approach to this surgery showed me how to do the operation through an incision measuring about an inch. He was so proud of his small incisions that he would take a picture of the large fragment of extracted disc held up next to a ruler, which was placed in line with the incision. He would give this photo to the patient after surgery. This was quite effective for word-of-mouth marketing. (“Wait, you need disc surgery? Go to my guy. Take a look at this!”) I became quite comfortable and efficient with this technique, and I found that most patients did not have significant postoperative pain at the incision site.

As minimally invasive spine surgery became popular, as patients started to ask for it, and as instrumentation companies pushed their tools for both the big and small cases, I felt obligated to try it. What I found, though, was that the juice wasn’t worth the squeeze. All of a sudden, what had been a relatively pared-down operation required more instrument trays in the room, a nurse familiar with the new tools, a large specialized retractor that had to be bolted to the bed, an unwieldy fluoroscopic “C-arm” machine that seemed to get in the way, and (because the new technique involved fluoroscopy) a heavy lead apron that I had to wear for at least the first part of the surgery.

Spine surgeons have started to realize that a minimally invasive discectomy actually seems to increase the likelihood of one particular complication: leakage of cerebrospinal fluid. That’s because the surgeon must use a rigid and narrow retractor, which makes it difficult to achieve unfettered access to all the necessary anatomy, especially when the surgeon is still on the steep part of the learning curve. As for the prospect of reducing postoperative pain, an original selling point of the new approach, I have not been impressed. I will admit that the new tools enable surgeons to operate through an incision that is slightly smaller than my usual inch. Is anyone excited?

For all my griping, I am inspired by the general direction of innovation in surgery. I can’t help believing that the answer to the fiddle factor is better technology, not less technology: after all, the innovative leaps in other fields leave medicine far behind. The most high-tech equipment available to the brain surgeon pales in comparison with the technology onboard a fifth-generation fighter jet, or in a modern nuclear power plant.

If we can catch up a bit, it will be fascinating to see what’s in store for neurosurgeons of future generations. But we should be careful what we wish for. Just as technological advances in nuclear plants and fighter jets try to maximize safety and efficacy by minimizing (or even eliminating) the human element, we should realize that the ultimate advances in surgery will take aim at perhaps the most fickle tool in the operating room: the surgeon.

Katrina S. Firlik is a neurosurgeon in Greenwich, CT, and the author of Another Day in the Frontal Lobe: A Brain Surgeon Exposes Life on the Inside.