March 15, 2023
Swedish otolaryngologists were the first to use microscopes in surgery about a hundred years ago. For modern neurosurgeons, the operation and application of operating microscopes is already a basic skill, because many brain and spinal cord neurosurgeries require operating microscopes to maintain a high degree of safety and accuracy.
In fact, in the history of neurosurgery, the invention and application of the operating microscope has a symbolic status. In operating the operating microscope, it may also reveal some life principles.
Neurosurgery originated in England in the 19th century, and began to treat brain diseases with open brain surgery. However, its main development occurred in the United States after entering the 20th century, with Harvey Cushing (1869-1939) and Walter Dandy (1886-1946) as the main representatives, among whom Cushing is recognized as the “father of modern neurosurgery”. And Dandy established the world’s first neurosurgery intensive care unit.
Both of them pioneered many neurosurgery operations, laying the foundation for the definition of many neurosurgery lesions, angiographic examination, and the design of surgical instruments.
However, early neurosurgery operations were all large-diameter craniotomies, probably because the diagnostic technology was not yet mature at that time, and brain tumors or abscesses were often too large when they were diagnosed, so that they could not be treated without “opening a large wound”. In addition, many surgical instruments were introduced from general surgery at that time, and neither the design nor the fineness were enough for application in small wounds.
From this, it can be imagined that the early “brain surgery” was quite traumatic, and patients had a higher chance of complications after surgery and a longer recovery time. This period is known as the “traditional neurosurgery era”.
Until 1957, Theodore Kurze (1922-2002) of the United States introduced the operating microscope into neurosurgery, creating the “microneurosurgery era”.
Operating microscopes were actually used in otolaryngology and ophthalmology earlier. Swedish otolaryngologist Carl Nylen (1892-1978) performed the first otitis media operation with the aid of a microscope in 1921. By the 1950s, microsurgery had become routine in the House Clinic, a famous ear hospital in Los Angeles, USA. Theodore Kurze, a neurosurgeon also in Los Angeles, was deeply inspired after observing the microsurgery at the House Clinic. In 1957, he performed the first neuroma removal operation on a 5-year-old patient with the help of a microscope.
When it comes to truly developing neurosurgical microsurgery, Gazi Yasargil, another iconic figure in the neurosurgery field, has to be mentioned.
Born in 1925, Professor Yasargil studied in the world’s first microneurosurgery training center in Burlington, Northeast of the United States. On October 30, 1967, he completed the world’s first superficial temporal artery-brain surgery in Zurich, Switzerland. Artery bypass surgery.
Relying on the magnification effect of the microscope, many careful operations that were previously impossible for the naked eye have been created. Moreover, with the advantage of the high-intensity light source of the microscope, it is possible to safely separate brain tissue in the crevice or deep in the narrow canopy. Since then, the concept and technology of microneurosurgery have been widely recognized worldwide, and the complications and recovery time of brain surgery have been greatly reduced. Professor Yasargil was also dubbed the prestige of the great man of neurosurgery in the 20th century.
not too much
Today, surgical microscopes not only have clearer magnification, deeper depth of field, more flexible support, and brighter light sources, but also have different imaging functions. With various contrast agents, tumors and blood vessels can be highlighted. In addition, navigation images can also be provided. It is integrated into the microscopic image to make the operation more precise and safe.
While a great invention, the operating microscope is still just a tool. In order to do a good job of precision surgery with minimal trauma, in addition to other fine surgical instruments, people are more important. Therefore, the entire concept and technology of microneurosurgery originated from the birth of the operating microscope, but it is not limited to “operating with the operating microscope”.
Including the author at that time, many young doctors who are new to operating microscopes naturally like to put the microscope at the maximum, thinking that the bigger the microscope, the clearer the vision. However, the larger the image is zoomed in, the narrower the field of view and the shallower the depth of field will be. In this way, the slight tremor of the hand is also amplified at the same time, and the focus tends to become unstable. Due to the narrowed field of view, it is sometimes easy to overlook other locations of the surgical wound. For example, once, when a colleague was dealing with a brain tumor, the anesthesiologist told the colleague that the patient’s blood pressure was low and that there might be bleeding somewhere. However, the colleague only looked at the microscope magnified 20 times, saying that there was no bleeding at the surgical site, and asked the anesthesiologist to check his equipment.
I suggested to my colleague to zoom out to take a look, only to find that a small scalp blood vessel was bleeding from the surgical incision, which stopped after being burned with an electric knife, and the patient’s blood pressure returned to normal.
The quality of modern microscope lenses is very high, and the maximum optical magnification can reach 25 times or even more than 40 times. However, there are not many surgeries that really need such a high magnification. Most of the surgeries can use about 10 times with ease. Instead, it is more important to ensure that the field of view is sufficient, that is, it is more important to include all the places that need to be seen within the line of sight.
If you want to zoom in on a certain location, you must first ensure that the places that will leave the field of vision are clean and without problems, and then increase the magnification to focus on the places that need to be focused. As for the magnification, as long as it is enough. This provides the best balance between magnification, field of view and depth of field. The first truth I learned from the operating microscope is that there is no need to use too much of many things, just enough.
In addition to the magnification function of the operating microscope, another equally important function is illumination. Surgical microscopes are equipped with advanced optical design and high-intensity light source to maintain sufficient illumination deep into the tissue and ensure that there will be no overlap of shadows, so that they can be seen clearly.
However, many doctors who are new to operating microscopes dare not move too much when the microscope is placed at a certain angle. Even if the position of the operation is from the center of the field of view to the edge of the field of view, I am not used to adjusting the angle of the operating microscope.
It should be noted that the clearest and brightest position of the microscope is usually in the center, and the mechanical arm device of the modern surgical microscope is more flexible and stable than the old one, which allows the doctor to adjust the angle and position at any time during the operation to achieve the best imaging effect. Some surgical microscopes have an automatic tracking function, which can automatically adjust and move according to the doctor’s operation position. I don’t know this function very well, and I still prefer to adjust it according to the needs and the progress of the operation. Instead, I feel more flexible.
The second truth learned on the operating microscope is that it cannot be static. On the contrary, if you can adjust your vision and angle in a timely and appropriate manner, not only can you illuminate the originally dark place, but you may even see more unexpected things.
master the rhythm
Before the operation, the doctor usually has a set of strategies and plans in his mind, such as how to find the lesion, which position to peel off the lesion is the safest or most effective to reduce blood loss, and how to deal with the deepest part.
However, these strategies may not be smooth, especially when we zoom in, because the field of vision is narrow, just like “I don’t know the true face of Lushan Mountain, but only because I am in this mountain”, because I am trapped in the magnified image and ignore it. The patient’s brain is comprehensive, and it is easy to plant deeper and deeper unconsciously, or go far away due to some small angle deviations, thus causing damage to other tissues.
Therefore, we need to re-examine from time to time to see if we need to modify and adjust the pace of the operation, so we need to zoom in and out from time to time, which is the so-called Zoom in and Zoom out.
That is to say, when the operation reaches a certain stage, we should zoom out a little bit to see the overall situation of the patient, and check whether there is no problem in the place where there were no problems before, whether the progress and scope of the operation are as planned, and whether there is too much or too little or deviation. , Do you need to adjust the plan, etc., and sometimes let the eyes take a rest for an excuse, and then adjust the angle and position of the surgical microscope as mentioned before, and then zoom in to observe the surgical position, and then continue to the next stage after seeing the texture clearly Operation. Zooming in and out in this way will not slow down the progress of the operation, but can make the operation more convenient, reduce the chance of making mistakes, and enable the doctor to better control the rhythm of the entire operation.
Therefore, the third truth I learned from the operating microscope is to understand the importance of timely and moderate Zoom in and Zoom out. You need to zoom in to complete your strategies and plans at each stage in detail, and you also need to zoom out from time to time to check your vision and changes in the general environment, and then zoom in… Finally, you can accomplish your goals more effectively.
Written by: Dr. Tianfeng
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