Evolution of laryngeal surgery in the past 20 years
Historical aspect on “roaring”
The term “roaring was already known in the eighteenth century as the respiratory noise produced during strenuous exercise that was associated diminished work tolerance (1). More over the relationship between left laryngeal paralysis and “roaring was confirmed by transection of the left laryngeal nerve.1 Science could, however not convince the law in England, which still stated in 1882 that “roaring was caused by thick mucus adhering the walls of the larynx. The idea that “roaring” could be an inherited trait came up as early as 1764, when a group of Danish stallions was brought to the Normandy, which resulted in a significant increase incidence of left laryngeal hemiplegia in the following years. The Royal College of Veterinary Surgeons disqualified affected Thoroughbred stallions form breeding in 1890, further underlining the close relationship between the disorder and breeding practices. Most commonly large breeds of horses were affected by the disorder, such as draught- and saddle horses.
At that time it was not possible to visualize the larynx during exercise; therefore the veterinarians had to rely on its digital palpation. It was soon recognized that the laryngeal muscles atrophied on the left side. In 1911 Williams described his findings in detail.
Surgical Procedures on the larynx
It is very interesting to note that most surgical procedures applied today in laryngeal surgery were developed 150 years ago by Günther Junior from Hannover (3). These procedures: vocal cordectomies, ventriculectomies as well as partial and total arytenoidectomies. With time additional procedures were developed.
The basic idea involved to create a fibrous band between the thyroid cartilage, the vocal fold and the arytenoids cartilage by obliteration of the ventricle. Several techniques were described involving simple removal with or without suture closure of the opening of the ventricle after removal of its lining, additional removal of the vocal cord, and cautery of the ventricle.
Williams developed a simple technique for ventriculectomy (2) in 1907 but Hobday was subsequently the one who really made this technique popular and it became to be known as the “Hobday Operation”.4 In the early days a laryngotomy approach through the cricothyroid membrane was selected, however with the introduction of lasers and modern electrocautery, the technique was modified to be performed in the tranquilized standing horse through an approach via the ventral nasal meatus (5,6). In some cases the laryngotomy was partially or completely closed (7).