A surgeon’s inside view of anatomical variation

Last year I wrote a short article about “The clinical significance of normal — and not so normal — anatomical variation.” Not long after, I came across the following excerpt from the first chapter of Sherwin Nuland’s superb book, The Mysteries Within: A Surgeon Explores Myth, Medicine, and the Human Body, “The Stomach: A Little Boy’s Big Secret.” I could not ask for a better passage to help me explain how strange and diverse “normal” anatomy can be — it’s perfect. But, such is my to-do list that it took me literally a year to getting around to getting it typed up. Here it is at last:

No matter how often a surgeon performs the same operation, it is different each time. Any operating room nurse can tell you that. The sequential precision of predictable steps so exactingly depicted in manuals of surgical technique resembles the real thing about as much as a diagram of human anatomy looks like a human being.

To take something simple: Of the many hundreds of appendectomies I have done during a career of thirty-five years, no two were the same. Even such a straightforward operative procedure for a straightforward disease, divisible into a short series of straightforward technical maneuvers that were standardized almost one hundred years ago, done by an operator of long experience — even under such circumstances every case is a novelty. And some of those novelties can be daunting tests of skill and confidence.

On bedside rounds one day during the period of my training, the senior attending surgeon, a man highly respected for his dexterity and judgment, was asked to name the half-dozen most difficult operative cases he had encountered in his career. After a moment’s thought, he replied that three of them had been appendectomies. His answer surprised no one in the group of interns and residents who were crowded around him. In the few years of our embryonic surgical experience, every one of us had already seen enough to appreciate what he meant.

Although the configurations of human innards do not vary nearly as much as do those of our outards (a word that exists in no dictionary but should), they nevertheless reveal unmistakable variations among individuals — and only surgeons ever find out about them. The way in which an organ is attached by ligaments and folds of tissue to its surroundings, for example, is in general predictable, and yet just enough personal difference occurs that an operator never knows  beforehand whether the viscus he is approaching will come up easily into his seeking hands or require deep dissection to free it. Friend appendix, in fact, epitomizes this kind of anatomical uncertainty. Being attached to the large intestine only at one narrow end of its wormlike body, the appendix is free to turn upward toward the liver, downward toward the pelvis, sideward toward the center of the abdomen, forward toward the abdominal wall, or even retrocecal, which means it has tucked itself up behind the bowel into a hidden location. The appendix may be as short as a stumpy inch or as willowy as five or six times that length. There is no telling where its tip may be found. Other organs, though not as variable, have unpredictabilities of their own.

And then there is the problem of fat. The copiousness of the cushions of fatty tissue lying between internal structures depends in general on an individual’s station along the spectrum between leanness and obesity. Thin people are a great deal easier to operate upon than are the chubbies, who hide vital structures deep within thick, greasy blankets of adiposity. Among those concealed vital structures are blood vessels, which have an obnoxious tendency to make uncharted course changes now and then, obstinately refusing to reach their destination via the route assigned to them by anatomy books. Lying in wait for the unwary, or perhaps lurking within a fatty bolster, an unanticipated artery or vein — and nerves are known to do this too — can affect the entire plan of a surgeon’s work, and sometimes its outcome.

Beyond even these considerations, the occasional occurrence of a congenital variation of structure must be taken into account. The operating team always has to be on guard for such an abnormality, especially because it may involve blood vessels or the slender ducts that carry secretions and other vital fluids to their destinations. Some of these inborn irregularities can present major challenges, or at least major surprises. From time to time, for example, one or another viscus or a part of it must be sought in an area of the body where it seems not to belong. I am not at all unique among surgeons to have removed thyroid tissue from the chest, found the right colon on the left side of the abdomen, and taken an ovary or appendix out of a hernia bulging into the uppermost part of the thigh.

Just to promote Nuland’s excellent book, I will continue the excerpt a little longer, even though the topic changes. He goes on to explain many more things that make every operation unique, even the common ones. But then he introduces an exotic case …

I have been referring here to operations done with relative frequency. For the reasons given or others, some cases will be so unusual that they stand out in a surgeon’s mind for the rest of his life. But in addition to that list, there exists a special category within even less commonly done procedures — these are the real rarae aves. By this I mean the one-and-onlies. These are the operations of such a unique type that the members of the team will regale one another with their details when they meet at reunions or conventions decades later, even in farflung parts of the world. Some of these procedures are firsts, or at least firsts in a given hospital — the first organ transplant, the first use of the heart-lung machine, the first video-controlled gallbladder operation — but some are memorable because no member of the team has ever seen their like before or since. Like all surgeons, I have a few of those once-in-a-lifetime adventures tucked away in the back of my mind, ready to be pulled out and relived at a moment's notice.

One of them involves the stomach.

My patient had been an independent citizen for all of six weeks, the first two of which were spent in the preemie unit …

It’s a great story!