The first laryngoscopy simulators were based on skulls. Adalbert von Tobold (1827–1907) of Berlin was an early adopter of indirect laryngoscopy and he developed a laryngoscopy phantom for practising the procedure before attempting it on patients. Tobold included a drawing of his simulator in a book on laryngoscopy and local treatment of laryngeal diseases published in 1869 (see Fig. 7.1) [3, p. 21].

Ruppaner provided a description of how Tobold constructed and used the phantom ,

For the benefit of beginners, to train the hand and eye, Dr. Tobold has introduced a phantom in the shape of a prepared skull fastened to a portable stand with slide and screw, into which is introduced a plaster of Paris cast of the larynx and trachea, with the tongue protruding, truthfully painted, and admirably adapted for the first practice of the art. A second phantom represents the head with open mouth and protruding tongue, into the neck of which is also introduced a larynx, for the purpose of studying the same inside, and gaining the requisite dexterity with the mirror before experimenting on individuals. In our demonstrations before pupils these phantoms are constantly used, and they are found of great advantage. [2, p. 31]

Ruppaner also described some other ways laryngoscopy simulators could be created including,

procuring a human tongue and larynx with the upper part of the oesophagus, and placing or arranging them in a skull with the lower jaw attached. This can readily be done upon a table, the skull being supported on a few books, or if the above is wanting the head and neck of a sheep will answer the same purpose. [2, p. 31]

Waldenberg also used a cadaver larynx but attached it at the end of a lead tube mounted horizontally to imitate the mouth and pharynx (see Fig. 7.2) [4, p. 34]. Emil Behnke (1836–1892) also used a skull-based model to learn indirect laryngoscopy but it had an artificial larynx. He described the model in The Mechanism of the Human Voice:

I made my first attempts upon a skull, to which I attached a plaster-of-Paris model of the voicebox, the whole being fastened to an iron stand.

I then introduced the little spy mirror, and tried to see and to recognize the various parts of the voicebox, which, let it be remembered, present a somewhat different appearance in the looking-glass from what they do if seen without it. Then I got a friend to mark my artificial voicebox, unknown to me, in various ways, and endeavoured quickly to discover what he had done. In this way I soon acquired a considerable amount of skill in handling the instrument, and also became thoroughly familiar with the image of the voicebox in the mirror. [1, pp. 73–76]

Garcia had practised laryngoscopy on himself, autolaryngoscopy, and Behnke described this technique in the book and recommended it to students noting,

Let not the reader who tries laryngoscopic investigations be discouraged if, at first, violent retching is the result. It does not so much arise from sensitiveness of the parts touched, as from awkwardness in introducing the mirror. If he perseveres he will soon be rewarded by a view of the pearly white vocal ligaments, and a little repeated practice upon himself will enable him also to operate upon others without causing them discomfort.

Behnke concluded the section on learning laryngoscopy by reminding the practitioner that it was their responsibility to have had a lot of practice and

… where the touch of the mirror causes retching and gagging, it is due less to the sensitiveness of the person operated upon than to the want of skill on the part of the operator. He should in that case renew his experiments upon himself, and continue them until he has fully mastered the use of the instrument, as it is not fair to make others suffer for his own clumsiness. [1, p. 79]

A report on the forty-seventh annual meeting of the British Medical Association, held in Cork, Ireland in August 1879, included some observations on the surgical, medical, and obstetric instruments and appliances on display. One item being exhibited by Messrs. Krohne and Sesemann (London) was a laryngo-phantom invented by Isenchmid of Munich with thirty drawings of the glottis in health and disease (see Fig. 7.3). The correspondent wrote “This will be found to be most useful for teaching purposes and in acquiring skill in the use of the laryngoscope” [7, pp. 376–377] and also strongly recommended Isenschmid’s phantom for practicing laryngoscopy [1, pp. 73–76].

The construction and features of Isenschmid’s phantom were detailed in Knight’s New Mechanical Dictionary published in 1884:

Laryngo-phantom (Lar-yn’go Fhan’tom): An apparatus devised by Dr. Isenschmid, of Munich, and intended to familiarize medical students and practitioners with as many of the details connected with the use of the laryngoscope as it is possible to learn before the application of the instrument to the living subject.

The phantom consists of three parts: first, there is a mouth of thin metal, with tongue and uvula made of red velvet. This is fixed on a laryngeal tube of metal, which has a slit by which the thirty painted images of different views of, and different conditions of the laryngeal tract can be introduced. The laryngeal tube is movable on a second tube, which is tightly fixed on a peg in the middle of a small box in which the whole apparatus can be packed. The anatomical dimensions are taken from nature. When in use the phantom is placed like the head of a patient who is about to be examined, one or two feet in front of the lamp, but aside from it, so that the rays coming from the lamp and passing the right ear of the patient on to the mirror fixed at the forehead of the observer, are reflected into the mouth of the patient. [8, p. 527]

McBride’s translation and enlargement of Gottstein’s Diseases of the Larynx: A text for students and general practitioners was published in 1885 [5]. The book included a section on barriers to examination of the larynx and one of the biggest obstacles identified was lack of practice.

Speaking generally, it cannot be too strongly impressed that many apparent difficulties disappear in the presence of dexterity on the part of the laryngoscopist, and this can only be obtained by frequent practice in laryngeal examination. As patients are not always available for the beginner, he may for practice use a phantom or autolaryngoscopy; for the former may be used a skull fixed on a stand and in the interior of which is hung a larynx taken from a body, or better still, a phantom made of pasteboard or plaster; those by Oertel and Isenschmid (in Munich) are particularly to be recommended.

Max Joseph Oertel (1835–1897) actually designed several simulators for teaching laryngoscopy, rhinoscopy, and laryngeal surgery [9]. The laryngoscopy simulator had a facemask made of papier mâché and the mouth, palate, and tongue, which were filled with wadding, were made of colored cloth or velvet (see Fig. 7.4). A horizontal tube represented the mouth and pharynx and life-size color prints of the glottis mounted on card could be inserted in a vertical tube that formed the larynx. The prints were copied from contemporary atlases of laryngeal diseases. Laryngoscopy was frequently performed to investigate hoarseness and the practitioners needed to be able to recognize abnormal movement of the vocal. Oertel designed a vocal cord muscle simulator to help students learn to diagnose causes of vocal cord palsies (see Fig. 7.5). At the end of the nineteenth century the Columbia University Department of Laryngology had “physiological models to illustrate the normal movements and the various paralyses of the vocal cords” [10, p. 24].

Oertel designed a separate phantom for examining the throat and for rhinoscopy (see Fig. 7.6).

Oertel noted that eye surgery was practised on both human and animal eyes in phantoms and he a designed a laryngoscopic surgery phantom that utilised an airway harvested from a cadaver or pig [9]. The simulator had a stylised face with an open mouth and was mounted on a stand. There were hooks to attach the tongue to the floor of the mouth and a clamp to hold the larynx in position (see Fig. 7.7). This simulator was described in publications by Labus [11] and Heryng [12, p. 65].

A larynx phantom of German origin was advertised in the catalogue of Truax, Green and Co. published in 1893 [6, p. 1015]. The simulator (see Fig. 7.8) was a head with an open mouth for laryngoscopy and had four models of the pharynx and larynx that could be inserted in the base. There was one normal model and the others reflected important conditions present at the end of the nineteenth century including tuberculosis and syphilis of the larynx and diphtheria involving the throat and larynx.

Towards the end of the nineteenth century, Franz Joseph Steger (1845–1938) perfected a fast and accurate method of making plaster-cast models that could be hand-painted to give a realistic appearance [13]. One of the models, made in collaboration with Carl Ernst Bock in Leipzig, Germany, was a realistic looking head for practicing examination of the nose and throat (see Fig. 7.9).

It was reported in the Columbia University Catalogue of 1894/1895 that the Department of Laryngology had “twelve laryngoscopic ‘phantoms,’ by Bock of Leipsic, for exercising medical students in the use of the various instruments preliminary to the examination of the living subject” [10, p. 74]. There were also “between one and two hundred anatomical models of the healthy and diseased larynx by Steger of Leipsic and Tobold of Berlin” [10]. The Catalogue for 1896–1897 explained students were expected to practice “Upon the ‘laryngoscopic phantom’ until he has acquired the use of reflected light with the aid of the concave head-mirror” [14, pp. 23–24]. Over the next few years teaching facilities must have expanded because the Catalogue for 1899–1900 reported the Department of Laryngology had “A large hall, fitted with nineteen separate stalls, each with lamp, ‘laryngoscope phantom,’ mirrors, and other instruments and conveniences for the instruction of classes of students in the practical use of the laryngoscope and rhinoscope” [14, p. 113].

When the Eustachian tube was catheterized, confirmation that the tube was in the correct position was partly by feel. Friedrich Voltolini (1819–1889), “an aurist of large practice”, was reported to have made “a very simple simulator for the preliminary practice of catheterisation” [15, p. 39].

The objective of practice on the simulators of Tobold and Isenchmid was to learn how to manipulate the mirror and light source to examine the pharynx and larynx. However, the mouth and airway are very sensitive and if the mirror or an instrument is allowed to touch them, the patient will gag or retch and the laryngoscopist has to suspend the procedure. Behnke, Gottstein, and others recognized this, and that was one reason they recommended autolaryngoscopy as well as practice on a simulator. What was needed for practising endolaryngeal operations was a simulator that provided feedback when there was unwanted contact between instrument and mucosa. Carlo Labus (1844–1909) working in Pavia, Italy, described the first interactive larynx simulator in 1878.

The “Laryngo-Fantome” design ed by Labus was approximately the size and shape of an adult oral cavity and airway (see Fig. 7.10). A small drawer in the position of the glottis opening was used to load a colored plate of healthy vocal cords or cords showing various conditions or foreign bodies in the model. One pole of a cell was connected to the handle of the mirror or other instrument and the other to the electromagnet on the top of the simulator that held up a flap. If the instrument made contact with the inside walls of the simulator the flap was released which simulated gagging or retching by the patient. The trainee would then have to withdraw the instrument, reset the mechanism, and try again.

Labus later modified the electromechanical mechanism and incorporated it in a laryngoscopy simulator (see Fig. 7.11) which made it look more realistic. The drawer to load different images of the glottis and simulated laryngeal polyps or foreign bodies that required removal was accessed at the back of this simulator, labelled A in the figure. The surgical instrument was connected to the terminal (F) and when contact was made with the walls of the simulated airway, the electromagnet (E) released a flap in the pharynx that blocked the view of the glottis. The mechanism was reset using lever (G) on the back of the simulator.

Whilst Labus modified his original simulator to make it look more natural, in the last quarter of the nineteenth century Jean Garel (1852–1931) of Lyon and Jean Baratoux (1854–1944) of Paris significantly improved the simulator but kept the machine-like form. The simulator designed by Garel, which he called a laryngo-fantôme, was made by Gustave Trouvè, a Parisian electrical engineer (see Fig. 7.12). Descriptions of these simulators were published in professional journals in France, Italy, Germany, and the United Kingdom. In place of the pictures of the glottis used by Labus, Garel’s simulator had an artificial larynx that he moulded from a cadaver. This larynx had electrical contacts embedded in various places (see Fig. 7.12) and the position of the contacts was shown on an illustration of the larynx on a plate on the front of the simulator (labelled g in Fig. 7.12). Each contact had a number that corresponded to the number on label attached to the other end of a wire connected to it (see Fig. 7.12). One pole of a cell, a primitive battery, was attached to a surgical probe (labelled p) and the other was attached to a terminal to which a wire from one of the points could be attached (labelled f). When the probe made contact with the correct point of the larynx the circuit was completed and which made the bell (labelled m) ring. Another structure would then be selected for identification with laryngeal probe or sound and the wire for that point would be plugged into the terminal. In Fig. 7.13 these wires are shown quite separate but as shown in Fig. 7.12 they exit the “neck” of the simulator in an untidy bundle. Garel also described a larynx that had small cylindrical holes to mount simulated laryngeal polyps or tumors of different sizes for practising laryngeal surgery.

A simulator designed by Jean Baratoux was made by Alphonse Gaiffe (see Figs. 7.14 and 7.15), a Parisian engineer [17]. In addition to the features of the Garel simulator this simulator had an electric rattling bell that made a noise if a probe was accidentally brought into contact with the walls of the airway [18, pp. 102–104]. Pellets of wax were used to simulate tumors in the larynx and objects could be inserted to practice removing foreign bodies [18].

Dundas-Grant (1854–1944) was an enthusiastic supporter of simulation in training and strongly recommended practice on the electric laryngo-phantom of Baratoux which he had used himself and he lamented that the simulator was not as well known in the United Kingdom as it might be [16]. Grant had noticed that each time a new point was chosen for location on the larynx of the simulator, considerable time was lost in finding the appropriate wire to plug into the circuit and he designed a physical graphical user interface [16]. Grant had a schematic drawing of the larynx engraved on an ebony plate which then had small holes drilled at each of numbered points. Each hole was then fitted with a small brass tube and the wires from the contact points on the larynx were then connected to the tubes (see Fig. 7.16). This was a useful modification that meant there was now just a single wire and any contact point could be selected simply by plugging that wire, attached to the instrument, into the appropriate hole on the drawing on the ivory plate.