Key points

Introduction

Laryngology as a field developed over the course of medical history from the desire to explore the body’s internal anatomy and function, that was not readily viewable by external examination. This enthusiasm was guided by both a fundamental desire to understand how people communicated through voice, as well as by the necessity to understand the disease processes that affected the airway and deglutition, thus immediately influencing survival.

Some of the earliest recorded study dates back to the early Greek civilization around 400 bc . The Hippocratic School had a basic understanding that the epiglottis helped protect liquids from entering the pharynx. During the Roman era, dental mirrors were being used to explore the oral cavity. Galen provided the names for the epiglottis and the recurrent laryngeal nerve in the second century ad .

This interest in endoscopic exploration continued through the Renaissance period with Julio Casserius, whose book titled “The Anatomy of Voice and Hearing” in 1600 ad detailed the laryngeal anatomy of mammals including people. During the turn of the 19th century, Anderesch, Swan, and Henle were involved in detailing the early neuroanatomy of the larynx, as well as its histology. Dutrochet, in 1806, communicated some early theories on passive vibration of the vocal folds to generate sound despite never having observed a functional larynx.

These early times set the stage for the explosion of technology and understanding of laryngeal function that occurred during the 19th and 20th centuries and continues today. Continuous efforts to improve visualization of laryngeal anatomy were the driving force for the creation and evolution of the field. Endoscopy and the stepwise improvements in endoscopic technology have provided the trunk from which operative interventions have been able to sprout.

Laryngologic surgery, as a result, evolved from office-based procedures to operating room surgery, and then back toward office-based surgery in the current day. This process occurred in a gradual but discretized fashion through the contributions of many people over the course of 200 years. It is easy to be unaware of or to forget the arduous course that the field has taken to get to the point where surgery on the aerodigestive tract can be performed in the awake patient in the office setting. It is important to understand the history of technical developments and practice so that one can continue to move forward. This article attempts to describe that course.

Introduction

Laryngology as a field developed over the course of medical history from the desire to explore the body’s internal anatomy and function, that was not readily viewable by external examination. This enthusiasm was guided by both a fundamental desire to understand how people communicated through voice, as well as by the necessity to understand the disease processes that affected the airway and deglutition, thus immediately influencing survival.

Some of the earliest recorded study dates back to the early Greek civilization around 400 bc . The Hippocratic School had a basic understanding that the epiglottis helped protect liquids from entering the pharynx. During the Roman era, dental mirrors were being used to explore the oral cavity. Galen provided the names for the epiglottis and the recurrent laryngeal nerve in the second century ad .

This interest in endoscopic exploration continued through the Renaissance period with Julio Casserius, whose book titled “The Anatomy of Voice and Hearing” in 1600 ad detailed the laryngeal anatomy of mammals including people. During the turn of the 19th century, Anderesch, Swan, and Henle were involved in detailing the early neuroanatomy of the larynx, as well as its histology. Dutrochet, in 1806, communicated some early theories on passive vibration of the vocal folds to generate sound despite never having observed a functional larynx.

These early times set the stage for the explosion of technology and understanding of laryngeal function that occurred during the 19th and 20th centuries and continues today. Continuous efforts to improve visualization of laryngeal anatomy were the driving force for the creation and evolution of the field. Endoscopy and the stepwise improvements in endoscopic technology have provided the trunk from which operative interventions have been able to sprout.

Laryngologic surgery, as a result, evolved from office-based procedures to operating room surgery, and then back toward office-based surgery in the current day. This process occurred in a gradual but discretized fashion through the contributions of many people over the course of 200 years. It is easy to be unaware of or to forget the arduous course that the field has taken to get to the point where surgery on the aerodigestive tract can be performed in the awake patient in the office setting. It is important to understand the history of technical developments and practice so that one can continue to move forward. This article attempts to describe that course.

Endoscopy early years

The field of endoscopy began to take root in 1807 with Philip Bozzini. In an effort to view the internal anatomy, Bozzini developed several speculae to explore the different human orifices. He was the first to use an external light source, in the form of candlelight channeled by mirrors, to visualize the internal body. He is not believed to have observed the larynx, but he did advance the entire field of endoscopy. The early attempts at visualization of the larynx were all variations of indirect laryngoscopy using a system of rudimentary mirrors to reflect the image back to the observer while attempting to channel light down to the larynx. Benjamin Babington is credited with developing the first “Laryngoscope” in 1829. With the patient in sitting position, Babington’s device retracted the tongue to allow the larynx to be visualized by a mirror, while illumination was provided by external direct sunshine. His efforts were subsequently forgotten due to a lack of publishing clinical papers. In 1841, Friedrich Hoffman developed the perforated concave mirror that is classically associated with the otolaryngologist. Avery used a concave mirror affixed to his head to reflect candlelight in conjunction with Bozzini’s scope in 1846. In 1855, Avery was the first to place a curved mirror on a headband, thus freeing both hands to examine the patient.

Manuel Garcia, a music professor, is oftentimes credited with being the first to perform indirect laryngoscopy. Garcia used a device similar to Babington’s to examine his own larynx but did not publish his work until 1854, several years after other investigators. In 1855, he published “Observations on the Human Voice,” in which he described vocal fold motion, as well as the generation of voice from the vocal folds. He was the first to describe the concept of the autoscopic laryngeal examination.

After the advent of tools that allowed for endoscopic views of the larynx, efforts began to apply these developments to the clinical setting. The first laryngology clinic was established in Vienna in 1870 by Von Schroetter. During this period, indirect laryngoscopy faced several technical hurdles. Both lighting for visualization and laryngeal anesthesia had always been formidable challenges to examination. Thomas Edison’s invention of the electric incandescent light bulb did not occur until 1879, and topical anesthesia for the larynx was not discovered until 1884. As a result, it was difficult to establish indirect laryngoscopy for everyday use in the laryngology clinic. In 1884, Koller discovered the use of cocaine for ophthalmic topical anesthesia, and Jelinek was the first to apply it to the larynx to remove a polyp. Before topical anesthesia, laryngeal examination required the process of habituation by the patient to overcome the gag reflex and laryngeal stimulation. Johann Czermak was the first to employ artificial light with a curved mirror to concentrate the light source, as he described in 1888. Czermak continued to perfect techniques and tools for indirect laryngoscopy to establish clinical relevance. He helped to educate many physicians at the time in indirect laryngoscopic operative techniques, notably Jacob Solis-Cohen.

Morell MacKenzie, also a student of Czermak, helped to establish the first hospital for throat diseases in the late 1800s. He was also the first to coin the term laryngoscope, although the devices that he used were still forms of indirect “Laryngoscopy” that reflected the image back to the examiner. MacKenzie spent considerable time improving and developing instruments for laryngeal examination and biopsy. He also authored the first textbook of throat diseases.

Most laryngology endeavors took place in Europe, until Horace Green brought the field to North America. He is touted as the father of American laryngology. Having completed his studies in Paris, Green immigrated to the United States and brought the field with him. Green had several significant accomplishments, including being the first to excise a laryngeal neoplasm under direct laryngoscopy using a spatula and curved tenaculum. He also was the first to introduce medication into the larynx and bronchi for treatment of local disease. In the middle of the 19th century, the practice of laryngology was performed by medical physicians and neurologists. Jacob Solis-Cohen, a general surgeon, helped to initiate the transition of the field into a surgical specialty. He was among the first surgeons to focus on the larynx and is believed to have performed the first viable total laryngectomy in 1884. During the same period, airway obstruction, often due to foreign bodies, was being treated surgically with tracheotomy or by cannulation of the larynx using indirect laryngoscopy.

The advent of direct endoscopy

These efforts in the 19th century opened the door for the contemporary field of endoscopy, which was coined by Antonin Desormeaux, a urologist, in 1853. Once clinical utility was established, the field and the technology were able to progress much more rapidly. Development of direct laryngoscopy, bronchoscopy, and esophagoscopy occurred very much in parallel with each other through sharing of technical leaps. Kussmaul performed the first the direct esophagoscopy in 1868. His concept for esophagoscopy was taken from studying sword swallowers and then applied using the Desormeaux urethroscope to evaluate the esophagus. In 1881, von Mikulicz developed the first electrically lighted esophagoscope using a platinum burner. However, it wasn’t until 1888 that Leiter replaced the burner with the incandescent light bulb for use with endoscopes. Having developed a strong enthusiasm for von Mikulicz’s esophagoscope, Alfred Kirstein is given credit for the developing the first true direct laryngoscope. The introduction of his device in 1895 ushered in a new era of modern diagnostic and operative laryngology. Interestingly, his “Autoscope”, as he called it, was described in the first issue of the Laryngoscope journal. In 1896, Gustav Killian was active in researching the possibility of using rigid scopes to explore the trachea and bronchi. Previously, Green had demonstrated that the subglottic airways down to the lungs could be instrumented. It was believed that if esophagoscopy could be tolerated safely, then bronchoscopy should be feasible. Killian was the first to demonstrate that airways could be safely explored by passing a 9 mm tube beyond the carina. He introduced the supine position and coined the term “Bronchoscopy”.

Chevalier Jackson designed his first laryngoscope in 1903. At the time, endoscope designs incorporated variations of spatulas and tubes to aid displacement of oral and pharyngeal structures. Jackson developed tubed designs for his laryngoscopes, bronchoscopes, and esophagoscopes. This design allowed for advancement of the scope through a more lateral approach, providing better distal exposure without obstructing the view. However, closed-tubed endoscopes conducted the standard proximal light source poorly. To find ways to deal with poor lighting, innovators began experimenting with distal lighting for endoscopes. Although it had been introduced previously in Europe, Chevalier Jackson is credited with developing a practical distal lighting method for endoscopy equipment in 1905. He used a side channel (tube within a tube concept) on his scopes to accommodate the light. In addition, he also introduced distal suction. He devoted a great deal of thought to patient positioning, as well as arrangement of equipment and personnel during procedures. In order to facilitate his operative setups, endoscopy was moved to the operating room. This transition to the operating room likely set the stage for future technology adoption.

With the advent of direct laryngoscopy, it became clear that laryngeal surgery could benefit from bimanual techniques. Killian introduced suspension laryngoscopy in 1911 serendipitously for the purpose of stabilizing the scope on the patient’s chest to draw better diagrams of the larynx. Lynch then made modifications to Killian’s apparatus, which helped to bring about its adoption in the United States. In 1920, he published the first series of early glottic cancers resected using direct laryngoscopy. Yankauer began to use magnification for endolaryngeal surgery but recognized the limitations of monocular vision. In 1910, Yankauer introduced a laryngoscope that was wide enough to permit binocular vision, but it did become popular until the widespread use of the binocular microscope. Edwin Broyles introduced bronchoscopes with magnification in the 1940s. Multiple scientists devoted time and effort to both improving magnifying telescopes as well as surgical techniques. These helped to develop the art of bimanual manipulation of the larynx.

The optical era

The state of endoscopy in the 19th and early 20th centuries was dictated by the lack of magnification of distant structures and inadequate visualization from poor lighting. Over the course of the past century, a quantum leap in endoscopic technology allowed for further development of the field of laryngology as well as the movement of surgical intervention from the operating room back into the office.

The 1950s were marked by significant advances made in optics and illumination. The advances in these areas occurred in tandem and were enablers for today’s surgical practices. In 1953, the Zeiss Optical Company introduced the binocular microscope. The coupling of a microscope with endoscopes was initially proposed for gynecologic applications. During the second half of the 1950s, Albrecht and Kleinsasser in Europe and Jako in the United States began exploring possible uses of binocular microscopy in the larynx. In 1960, Scalco described the use of the Zeiss microscope with the Lynch suspension laryngoscope. Binocular microscopes necessitated redesign of laryngoscopes to take advantage of stereoscopic vision. Also in 1960, Kleinsasser developed instruments for use under binocular microlaryngoscopic conditions. He introduced a laryngoscope that used warm air to keep the telescope from fogging, since cuffed endotracheal tubes were still not being used for laryngoscopy at that time. The 1970s saw the introduction of fiberoptic light carriers to replace distal incandescent light bulbs, along with laryngoscope redesign by Jako and Dedo. The advances in technology allowed Von Leden to create the modern technique of laryngeal microsurgery in the 1960s.

Further improvements in endoscopic image transfer were occurring simultaneously with advances in direct microlaryngoscopic techniques. In 1959, the rod lens optical system was invented by Harold Hopkins. His design used a glass rod to replace the air interspace between lenses of the existing telescopes at the time. The new optical design provided a wider viewing angle and absorbed less light during image transmission down its length. Interestingly, his invention received very little interest. Meanwhile Karl Storz, having observed the prototype for the flexible fiberglass gastroscope in 1960, realized the potential for using fibers to carry light. He began developing the idea of coupling a fiberoptic light source with rigid telescopes. His technology was a marked improvement over Jackson’s distal illuminating bulbs, which were not only dim but highly unreliable and would frequently burn out during the case. Before this, Storz had been involved in the development of instrumentation for otolaryngologic applications. He was familiar with the limitations of the current lighting and optic systems and recognized the need for improvement in both to provide better endoscopic visualization. Storz arranged to meet with Hopkins in 1965. The two partnered and quickly developed the Storz-Hopkins telescope. Their scope provided superb image resolution with unmatched illumination. This provided a marked improvement in the quality and ease by which to acquire clinical photography. Aside from its role in the operative theater, it also improved the ability to share and collaborate with others in the field on clinical problems.