Our next paper will discuss the history of the operating microscope in neurosurgery, spectacles to virtual reality, and this will be presented by Dr. Scranton. I'd like to thank everyone for having me here today. I did this project at the urging of my mentor, Dr. Grossman, and he said this will be a great oral presentation, and then I discovered I only have ten minutes to give it in. The question is, how do we get from a simple piece of polished rock to the foundation of our field today? So it took quite a bit of research and help from many people, and I'd like to thank all of them. The best quote I found about the operating microscope is from Dr. Ginetta. So he described it as, to do brain surgery before the microscope, you had to be able to accept the fact that people didn't do well, that you were hurting and maiming people by trying to help them. So this is the first known example of magnification. This is the Nimrud Lens. It's about 3,000 years old. It was found at the site of an Assyrian palace in modern-day Iraq. It was found by a British, Austin Henry Layard, which is why the other name for it is the Layard Lens. It's currently in the British Museum. It's a polished oval piece of stone, which was the common method of making lenses at that time. Similar examples are seen by the Babylonians, the Greeks, and the Egyptians. Several centuries later, we got into reading stones, which are usually used by monks. They were what we call a plano-convex lens or hemispherical lens for magnifying text. But a lot of microscopes are involved in physics and optical theory. And so one of the great leaps in optical theory was by, excuse the pronunciation, Ibn Sal. He was a Muslim Persian mathematician in Baghdad. So what's remarkable to me about this was he wrote this down in the 980s. This version of it, Schnell's Law, by Willebrand Schnell, describes the angles of incidence and refraction when referring to a light that's passing through a boundary between two different media. It's exactly mathematically equivalent to the one from several thousand years earlier. So eventually, lenses became a little bit more consistent, and they placed them into frames to create spectacles. And so this is a painting from the 1400s. It's the first description of spectacles on somebody. It's called the Great, excuse me, the Glass's Apostle. It's hanging in a church in Germany. It's from 1403. So spectacle makers were a big deal back then, and they were credited as being the ones to create the first microscope. There's a lot of controversy about who actually did it. Some believe it was Galileo in the early 1600s. But there's good evidence to show that it may have actually been Zacharias Janssen and perhaps his father in Middelburg, Netherlands. Now recently, this has been a little bit disputed because his neighbor, Hans Lippershey, there's documentation that he actually did it, and Janssen is sort of a questionable moral character. His brother-in-law worked at the Middelburg Mint, and he was caught several times counterfeiting coins. And then so he fled to another town where he was caught again and somehow got off because his confederate was the bailiff of the jail. But back then that carried the death penalty. Anyhow, so he took his lenses and created the first microscope. So this is the Janssen microscope. It's about 3 by 18 inches. It's a sliding tube. As you can see here, it goes in and out to help focus the light. It has about nine times magnification. The first use of the microscope in medicine was by an Italian, Giuseppe Campani. He was in Florence, and he described it in a letter to Pope Innocent XI. He was known as the best grinder and polisher of stones at the time because he developed a special lathe for polishing the stones. So he created the highest quality telescopes. And so this is actually a picture of the telescope. It's currently housed in the Billings Microscope Collection at the Medical Museum of the Armed Forces Institute of Pathology. It's at the National Museum of Health in Silver Spring, Maryland. And then this is a lithograph from the Vatican Archive from the original letter where he's describing his use to examine a leg wound. Now, some significant issues that all the lenses of the time suffered from were things like spherical and chromatic aberration. So in a perfect lens, all the rays of light are brought together to a single focal point, but in an imperfect lens, it's sort of chaotic, as sort of demonstrated in this picture here. Chromatic aberration is a little more complicated. Different wavelengths of light have different frequencies and reflect differently through the same media. And so what this looks like in real life is, for example, this photograph. In areas where there's a big contrast between dark and light surfaces, things become very fuzzy. So you can imagine how that can be a problem underneath an operating microscope. So to help solve some of these problems, this gentleman, his name is Ernest Abe, has a famous mathematical formula named after him, which he described. He was a professor of mathematics and physics in Jena, and later in his career became the research director of Zeiss Optical Works. So he was able to standardize optics through deriving some mathematical formulas to create consistent lenses. One of them was the Abe sign condition, which is a condition that has to be fulfilled in order for a lens or optical system to produce sharp images both on and off axis. He also had a solution to the chromatic aberration with his apochromatic lens. So he took three different materials and put them together to help focus the different frequencies of light to a common point. This design is still used today. So getting a little bit more into medicine, the first ones who really used the microscope were the ophthalmologists. So Carl Wilhelm von Zendler was the father of ophthalmic microsurgery and then inspired Lempert and Storch to use it as well. By 1893, we had the idea of stereopsis, but before that we had to use these monocular microscopes. The first one to use it in cranial surgery was nodal laryngologist Carl Olaf Nylund, who was also quite famous in his country for competing in the 1912 Olympics as a tennis player. But he repaired a labyrinthine fistula. His chairman took this idea and used a dissecting microscope and added a light source, which I guess is a little bit closer to the modern microscope. But a lot of the innovations that we use today that really make our field possible were discovered sort of in the 50s with improvements such as beam splitting technology, where you could now have an assistant. That's crucial because it's very difficult to teach somebody microsurgery without having someone there, you know, okay, move your hand a little to the left, a little to the right, now don't do that. It's what we as residents hear all the time under the microscope. After that became stands with counterbalances and magnetic brakes, so you could move the microscope in 3D. And Hans Littman in the 50s created a system where you could change the magnification of a microscope while maintaining a constant focal length. Again, very critical to our field. Many in this room know this man, Theodore Kersey. He's a very famous figure. We owe a lot of credit to him. So he was at the University of Southern California, and he read a paper from William House about his use of the microscope on a stapes operation. That sort of inspired him to sort of play around with this microscope for about a year in the lab, and then he decided to try it on a patient. So there's a real interesting video that you can find on YouTube that AANS produced where Dr. Ginetta was actually interviewing Dr. Kersey for almost an hour and a half, and he goes through some of this. And as the story goes, he snuck the microscope out of the back of the hospital, loaded it in his pickup truck, drove it across town to a children's hospital where he did an operation. It was for an auditory canal tumor. One of the big problems they had was in sterilizing or draping the microscope. He experimented with sheets that were sewn together. Eventually they tried ethylene oxide sterilization. He finally settled on turkey bags. And so he would sterilize turkey bags. And on the second operation, he was going to try to anastomose the stump of the facial nerve to the hypoglossal, presumably to fix some sort of deficit. And unfortunately, as never happens in modern times, the equipment wasn't ready. They weren't able to sterilize the bags in time. And so he did the operation the standard way. It was ready just in time for him to start closing. So he inspected it under the microscope again and realized the anastomosis was terrible and redid the whole operation with the microscope. He inspired some others, such as Robert Rand, Lawrence Poole, and Charles Drake to use the scope. But almost simultaneously on the East Coast, in Vermont, was this gentleman. Originally he was mentored by Dr. Penfield, but he was interested in doing an open surgical embolectomy for MCA stroke. And so he worked with a vascular surgeon there, Julius Jacobson, where they created a microsurgical research and training lab in Vermont. It was the first of its kind. He even offered a two-week microsurgery course. And this is actually where Professor Yostergill went to study. And he worked with him for a number of years developing his microsurgical techniques in his lab in Vermont. And then in modern times, there's sort of this thought that the brass and glass of a microscope has achieved the most it can, and a lot of the improvements now focus on the add-ons. You know, what else can we do to enhance the image and visualization? So we have a lot of things that we're quite accustomed to, counterweights, automatic balancing, immunofluorescence, immunofluorescence for tumor surgery. And, you know, this is still something very important to our field because, as you can tell, you know, just coming to this meeting, three of some of the largest boosts in the meeting hall are showing the latest developments in microscopy. So thank you, everyone, for your time. Thank you.

operating microscope

neurosurgery

history

microscopy technology

advancements