48 The History and Future of Endoscopic Skull Base Surgery

Wolfgang Draf

In all specialties dealing with the sinuses located deep in the body, tubes and cavities have been needed from the very beginning of modern practical medicine for transmitting light into these hollow spaces. This common necessity was the reason why otology, deriving originally from general surgery, as the complications of otitis media frequently required surgery, rhinology, and laryngology, originating in internal medicine for diagnosis and treatment of tuberculosis, have been united as the field of otorhinolaryngology. The first specialty in which endoscopy was developed was urology, where it was used to examine the urethra and the bladder.¹

Very early endoscopic diagnostic and therapeutic procedures have been used by several disciplines, of which otorhinolaryngology was one of the first. In neurosurgery it took much more time until the endoscope was introduced as a surgical tool, mostly in interdisciplinary cooperation with otorhinolaryngologists interested in skull base surgery. There are several historical reviews of endoscopic skull base surgery,^2–4 some of which discuss the development of endoscopic pituitary surgery.^4,5,6

The advances in endoscopic skull base surgery demanded a new, much more detailed description of anatomy. We have to be grateful for the immense work and cooperation of three outstanding clinically oriented anatomists: Johannes Lang (Fig. 48.1), the founder of microanatomy; Albert L. Rhoton (Fig. 48.2), who developed surgical microanatomy; and Manfred Tschabitscher (Fig. 48.3), who taught the endoscopic anatomy of the skull base.

I became interested in the Hopkins telescopes in the late 1960s, after having been disappointed with the older generation of telescopes. The main stimulus for developing the Hopkins telescopes was the idea that nasal and paranasal sinus endoscopy is needed not only for improving diagnostics but also for therapy.

Endonasal surgery using just a head light and the naked eye was developed at the turn of the 20th century.7 Endonasal drainage of the frontal sinus was already being successfully performed.⁸ Because visual tools such as the microscope and endoscope had not yet become available, and anesthesia had not reached the level of providing a surgical field with minimal bleeding, it was difficult for the average surgeon to perform endonasal sinus operations and in particular to reach the frontal sinus through the nose. Many complications had been reported. Mosher⁹ stated that endonasal ethmoidectomy was the easiest operation with which to kill a patient. Therefore, between 1920 and 1980, endonasal surgery was abandoned at most centers worldwide, with only a few exceptions.^10–15

The real revival of endonasal surgery started when H. Heermann began to use the operating microscope, primarily introduced for microsurgery of the ear,^16–19 for various operations through the nose, such as for sinus surgery of inflammatory diseases, but also for pituitary operations and others (Figs. 48.4, 48.5, 48.6, and 48.7).

Evolution of Endonasal Endoscopic Surgery

Early attempts to look into the maxillary sinus were reported by Hirschmann²⁰ (Fig. 48.8). Nitze²¹ used the cystoscope for naso- and antroscopy. Various attempts to look into the maxillary sinus were reported by Reichert²² in 1902 and by others.^23–25 The following decades witnessed the ups and downs of sinus endoscopy, which was also called antroscopy, engendered by a succession of technical improvements.

The real breakthrough to endoscopic^26,27 and microendoscopic (which I reported in 1982) surgery in otorhinolaryngology is attributed to the ingenuity of Harold Horace Hopkins (Fig. 48.9), a professor of physics at the University of Reading, United Kingdom.^28–30 It was his idea in 1954 to construct a flexible endoscope,³¹ which was developed into a useful prototype by the American gastroenterologist Basil Hirschowitz together with the physicist Larry Curtis. They presented it for the first time in 1957.^32,33

Although Hopkins was disappointed by the lack of support for the development of the flexible endoscope, he also recognized the legitimacy of the complaints of the British urologist J.G. Gow about the poor quality of the rigid endoscopes that were available on the market at that time. After he received a small grant of about 3000 British pounds, he began work to revolutionize the existing optics technique for constructing endoscopes28^,34; he replaced the relay of lenses with interspaces of air and glass inside the shaft. The higher refractive index of glass in comparison to air increased the viewing angle and thus led to the very welcomed decrease of the diameter of the instrument. This ingenious invention increased light transmission by a factor of nine, which meant an approximately 80-fold better illumination. The image quality improved dramatically with regard to brightness, contrast resolution, and color fidelity.

As frequently is the case in such situations, the brilliance of this invention was not recognized immediately. The first presentation of the new telescope at a urology meeting in Rio de Janeiro in 1961 was mostly ignored. It was Dr. George Berci (personal communication, 2005, 2009) (Fig. 48.10) of the United States who brought together the genius physicist Hopkins and the no less ingenious instrument maker Karl Storz from Tuttlingen (Fig. 48.11). Hopkins had given Berci a demonstration of the new invention of the rod lens system in London. Then Berci went to Tuttlingen and urged Storz to visit Hopkins in England. Storz realized immediately the importance of Hopkins’s invention. He and Hopkins got along well and worked well together, and thus construction of the telescope began. Storz constructed the first practical rigid Hopkins telescope that was stable enough for daily use; it separated the light source from the telescope (so-called cold light28). Since 1969, rod-lens endoscopes have also been produced by Richard Wolf in Knittlingen, Germany.²⁸ Since then, the rigid telescopes have continually improved, so that today we have, for example, a 5-mm Storz endoscope for tumor surgery in the central skull base, which was initiated by Aldo C. Stamm of Sao Paulo, Brazil (Fig. 48.12). Further construction is already underway of a telescope that will enable not only three-dimensional (3D) visualization but also 3D recording of endoscopic surgery without increasing the diameter of the telescopes.

It is not an overestimation to say that with these telescopes, a new era in endoscopic surgery began for many medical disciplines and for veterinary medicine. In otorhinolaryngology it was Messerklinger (Fig. 48.13) who in the late 1960s began to use an endoscope as a visual tool, having already studied the function of nasal and paranasal sinus mucosa for many years with a microscope. The small diameter of the new telescopes, the high light intensity, the wide angle view, and the magnification, which brings the endoscope near to the object of interest, gave him a new inside view, without the need of major procedures to expose these areas, for recognizing the importance of minor pathologies in the ostiomeatal complex and for recognizing the pathogenesis of inflammatory diseases in the paranasal sinuses. He noted that most of these sinuses drained into the middle nasal meatus.³⁵ His student Heinz Stammberger (Fig. 48.14) disseminated Messerklinger’s work throughout the world and is an important contributor to the continual evolution in this field.

All of this work paved the way for doing surgical procedures in smaller anatomical areas, as I began doing in 1973, culminating in the concept of functional endoscopic sinus surgery for the treatment of inflammatory diseases (Fig. 48.15).³⁶ The International Functional Endoscopic Sinus Surgery (FESS) courses in Graz and in Fulda began at about the same time in 1985–86. At first these courses were competitive, but a few years later a fruitful exchange of philosophies and practical techniques originated when Stammberger was teaching and operating at the course in Fulda and I was lecturing at the course in Graz.

At that time, in the 1970s, I believed that too many radical procedures were being done to treat inflammatory diseases of the paranasal sinuses, resulting in too many negative side effects. After Caldwell–Luc procedures were performed, we saw about 20 to 30% of our patients develop infraorbital nerve neuralgia because of surgical irritation of this nerve and because imaging was limited to plain x-ray. For exceptional situations, such as the suspicion of a tumor, conventional tomography was available. By comparing endoscopic examinations of the maxillary sinus with diagnosis based on plain x-ray images, we found that in 30% of our patients an incorrect diagnosis was made on the basis of plain x-ray. The goal of systematic endoscopic evaluation of the paranasal sinuses was different: I wanted to improve the diagnosis and treatment of sinus diseases.