Cavernous Sinus - You Better Don't Know About It
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Dr. Dolenc is a member of the Slovenian Academy of Sciences and Arts, a member of the European Academy of Sciences and Arts as well as an honorary or permanent member of numerous international neurosurgical associations. He is a lecturer at the Medical Faculty in Ljubljana. Since 1987, he has been the Head of Neurosurgery Department of the University Medical Center Ljubljana. He is also Professor of Neurosurgery at the University of Virginia, Charlottesville, USA. He is even better known abroad than in Slovenia.
His work is considered as a landmark in the history of neurosurgery, as quoted by Mahmut G. Yasargil in the Foreword to Dolenc's book: "Anatomy and Surgery of the Cavernous Sinus" in 1989. M. G. Yasargil - Neurosurgeon of the Century - wrote: "There is no doubt that this type of microsurgical anatomy study is a new step in the 100 year history of neurosurgery. Finally, this work reconfirms the necessity for the future generations of neurosurgeons to work in the microsurgery laboratory; not only for understanding the surgical anatomy, but to acquire the considerable technical skills necessary to perform surgical approaches of this complexity."
Beginnings
He recalls his professional beginnings to be a strange coincidence connected with a terrible accident. In 1966, an English airplane crashed at Ljubljana Airport and almost one hundred passengers were killed. The late Dr. Janez Miličinski, Head of the Forensic Medicine Institute at Ljubljana Medical School, together with his team identified most of the victims despite the fact that the bodies were badly damaged. The British people were amazed by this extraordinary effort, and the British Consul wanted to thank Ljubljana's Hospital where 18 survivors were treated. He wanted to award the Hospital, and Dr. Milan Žumer, chief of Neurosurgical Department expressed his wish for an operative microscope. That is how Dr. Dolenc started working with a microscope, at first on cadaver specimens but in 1969 already on the patients.
In 1967, the first report on microsurgical reconstruction of injured peripheral nerves was published by Dr. Smith from the Walter Reed Army Medical Center in Washington, USA. Only then did the microsurgical method start spreading around the world. In 1968, Dr. Yasargil, who studied micro-techniques in Vermont, USA, organized the first International workshop for micro-neurosurgical techniques in Zürich. Dr. Dolenc carefully followed all these novelties.
He started with peripheral nerve surgeries because he thought them the least dangerous. But in the early 1970s he started to push forward the frontiers of what seemed impossible. He introduced microsurgical techniques into brain operations; he operated an intracranial aneurysm (an abnormal blood-filled swelling resulting from a localized weakness in the wall of the brain vessel) already in 1974, during the period of his residency program. Clipping of the aneurysm and/or strengthening of a weak segment of the vessel's wall, which can easily rupture and cause severe consequences or even death of the patient, takes an extraordinary skill. The use of the operative microscope in such an operation, which later became a standard, was a pioneering idea at the time.
It was also Dr. Dolenc's idea - new at the time - that a patient with a ruptured intracranial aneurysm is operated sooner than it was then usual; usually such patients were hospitalized, they had to rest for six weeks before the diagnostic procedures were done, and so many patients died during this period due to repeated ruptures. Dr. Dolenc suggested and started performing surgeries in the acute stage, which had been performed only once before in England. Slovenia was then followed by Japan. The method was later accepted as a routine practice worldwide.
Pushing the Frontiers
Later, he focused on the microanatomy dissections of the central skull base. He was especially interested in the cavernous sinus, which was at that time a still poorly understood region. It seemed surgically almost inaccessible. The cavernous sinus is a collection of thin-walled veins in the vicinity on the left and on the right side of the hypophysis, including the carotid artery and four cranial nerves, which are all extremely important and sensitive structures - that is why this region is also referred to as a "veritable jewel box". Operating in this region is extremely demanding. In the past, people suffered permanent consequences after operation: double vision, paralysis, even death due to the injury of the carotid artery and the veins in course of surgery.
In 1980, after long-continued experimental microanatomical studies, Dr. Dolenc successfully approached this area - he performed the first successful surgery in the cavernous sinus without stopping the heart; that is without extracorporeal blood circulation, which was a standard procedure at the time. Extracorporeal circulation during this surgery presented to surgeons two main problems; one was limited time due to the fact that extracorporeal blood circulation results in damage of the body cells after a certain period of time. The second problem was the shortage of space for operating within the skull base (as mentioned above it is a very 'crowded area'). Dr. Dolenc solved the first problem by means of temporary stoppage of blood flow through the carotid artery inside the cavernous sinus. Equally important was removal of a part of skull base bones to gain the space for surgery. But nonetheless, when he presented his operating procedure at the International Neurosurgical Congress in Munich in 1981, only two out of three thousand neurosurgeons did not object it!
Neurosurgical Books
But Dr. Dolenc continued his work together with his colleagues in Ljubljana, coming to new discoveries, and the interest for those grew. In 1986, in Ljubljana, he organized the 1st International Symposium on the Cavernous Sinus (The 1st ISOCS). All the questions asked were impossible to answer, that is why he decided to publish a book titled "A Multidisciplinary Approach to Vascular and Tumorous Lesions" in 1987. In 1989, it was followed by a 'manual book' "Anatomy and Surgery of the Cavernous Sinus", which sold out in less than one year. The latter was the leading neurosurgical book of the year and the discoveries of Dr. Dolenc were estimated as a landmark in the history of neurosurgery.
Dr. Dolenc kept working in clinical as well as in research fields. In the course of the following years, preparing a new book based on new discoveries (he rejected the publisher who wanted to reprint his book published in 1989). In 2003, his third book "Microsurgical Anatomy and Surgery of the Central Skull Base" was published, analyzing more than 2,500 clinical cases. Dr. Dolenc says he's proud of it because "it is readable even to tired and sleepy neurosurgical residents due to their workload".
In September 2006, in Ljubljana, he organized the 2nd ISOCS - 20 Years Later, because cavernous sinus is still in the focus of his interest. Recently, he and his good friend and colleague from USA, Dr. Larry Rogers, edited the next book "Cavernous Sinus - Developments and Future Perspectives", which contains articles by world experts presenting the state-of-the-art in this field.
It is interesting that after decades of surgical workload, long surgeries do not seem tiring to him; he does not see the surgeries as hard work, because he always finds them extremely interesting.
Future Perspectives
Today, after almost three decades of neurosurgical practice and work in the laboratory, the eyes of Dr. Dolenc are - as ever - directed towards the future. Currently, he is working on the recently-founded International Institute for Neurosurgery and Neuroresearch (IINN). The Institute, which links numerous experts around the globe, will be focused on demanding operations in the skull base tumors and vascular lesions, but equally important is research and postgraduate education. "Slovenia has already its important position on the world map of neurosurgery", explains Dr. Dolenc, "and if we manage to join the experts and activities of the IINN under one roof, preferably in Ljubljana, this position will only strengthen I have always been proud to be Slovene; not because our nation settled this beautiful part of the world, but solely because of its contribution to the world's treasury of science and art".