Thyroid surgery

The obvious appearance of a goiter protruding from a human neck led to written and artistic accounts of thyroid disease many centuries ago. Chinese literature mentioned goiters as early as 2700 bc and suggested seaweed and sea sponge, a significant source of iodine, as remedies. The Romans commented similarly but also documented occasional operative treatment for an enlarged thyroid. Goiters are often seen in historic artwork ( Fig. 1 ). Leonardo Da Vinci, a visionary of contemporary anatomic sketching, drew an anatomically accurate, detailed, healthy thyroid around 1500 ad , noting both its lobular and bilateral nature.

Etching, 1780s. Note the goiters. ( Courtesy of the Wellcome Library, London; with permission.)

Despite the relative frequency of thyroid disease in society, the gland was not named until the sixteenth century when Bartholomaeus Eustachius of Rome characterized it as a single “glandulam thyroideam” with two lobes connected via an isthmus . Textbooks from the nineteenth century noted thyroid enlargement, usually in females, that was not climate or condition specific but recognized to be under the influence of heredity .

Although the appearance of a symmetric neck mass was considered by some to be attractive in women from endemic populations, others found it concerning. Several of these anatomic distortions were life threatening, producing a suffocating effect on the trachea and encouraging surgeons to attempt surgical extirpation for relief of compressive symptoms and even to save the patient’s life. Thyroid surgery was undertaken well before thyroid gland physiology was understood. The procedures were often fraught with complications, including massive hemorrhage, infection, and injury to surrounding structures, all of which were associated with morbidity and mortality rates of nearly 40%. Harold Ellis, in his book A History of Surgery , included the opinion of early American academic surgeon Samuel David Gross on thyroidectomy. In 1866, Dr. Gross wrote that “every step he [the surgeon] takes will be environed with difficulty, every stroke of his knife will be followed by a torrent of blood, and lucky will it be for him if his victim lives long enough to enable him to finish his horrid butchery.” Theodor Billroth in 1881 had noted that these procedures were “a matter of no little difficulty and danger .” In Billroth’s time, there were three main thyroid operations: (1) noncutting, (2) cutting without tissue removal, and (3) enucleation and ligation. The noncutting operations included punctures, iodine injections, and cautery. The cutting operations were accomplished with thyroid artery ligation or dividing the sternocleidomastoid or cervical fascia to decrease the mass effect on the trachea and relieve difficult breathing. Thyroid goiters and nodules of varying sizes and densities could be enucleated, with ligation of vessels and tissue in an attempt to control hemorrhaging.

Before the antiseptic technique described and employed by Joseph Lister in 1867, infection and sepsis often caused patient demise in all fields of surgery. Many surgeons were unwilling to undertake nonemergent thyroid surgery due to the high incidence of infection that was often fatal. Theodor Billroth observed a 40% mortality rate associated with thyroid gland surgery, almost entirely due to sepsis. As a result, he refused to operate on the thyroid except in emergencies. He was quoted as saying, “On carefully reviewing the results of my experience, I have come to the following conclusions…much less favorable in its results is the operation for completely removing deep-seated substernal or unilateral bronchoceles (goiters), accompanied by a high degree of dyspnea; even in cases in which the operation is immediately successful in saving life, the ultimate result is frequently unfavorable .” Despite this attitude, many of his surgical apprentices and students went on to make a major impact in the development of safer and more effective thyroid surgery. The turning point for surgical management of thyroid disease came at the end of the nineteenth century when Theodor Kocher developed innovative operative techniques and used the new techniques of antisepsis to lower the morbidity and mortality of these operations. Enucleation and ligation became the mainstay of thyroid surgery. This focus on anatomy, hemostasis, and antisepsis made thyroid gland surgery a safer endeavor.

Specifically, Kocher implemented the strict use of antiseptic technique in the operative environment and took meticulous care in dissecting and controlling vessels, thereby avoiding hemorrhage. His approach often used a vertical midline incision, but he later altered this twice, first, to an approach along the anterior border of the sternocleidomastoid muscle for better visualization and, second, to a transverse incision. For hemostasis, he ligated arteries as he came upon them during dissection of the vascular plane between the thyroid capsule and the goiter, with associated vessels in small isolated bundles of tissue. He also paid close attention to the anesthesia methods. One of Kocher’s few mortalities was secondary to chloroform anesthesia. From that point onward, he used only local anesthesia with cocaine. By avoiding infection and hemorrhage, using local anesthesia, and building upon his experiences, Kocher’s operative mortality rate declined to less than 1%. This success led to thyroid operations being conducted for less emergent disease and becoming more mainstream.

European surgeons dominated innovations in thyroid surgery until the continent was ravaged by twentieth century wars. Surgeons from the United States would visit clinics in Europe to learn surgical techniques and apply them to their own clinical practice. Charles Mayo was one such surgeon who focused a great deal of his own clinical practice and research effort on the thyroid gland. In 1907, he used the term hyperthyroidism to describe the cachectic nature of hyperthyroid disease, although it would be some time before the overproduction of thyroid hormone and its effects on cellular and organ function were fully elucidated. He achieved a mortality rate of 5% in patients having thyroid gland surgery. For these contributions he has been named, “The Father of American Thyroid Surgery.”

Similar to the eras before and after Lister, anesthesia had its own impact on thyroid surgery. Before general anesthesia was available, there was little to make the patient comfortable during the procedure. Patients were told not to move and were even tied down to the operating table. Chemicals such as ether had been in use for years but not necessarily in a controlled way. The first documented use of general anesthesia for a thyroid operation was in 1849 by Nikolai Pirogoff using ether . Over the next century, including two world wars, the technologies of anesthesiology improved dramatically, including managing the difficult airway. This progress proved integral to approaching a large goiter impinging upon the trachea, causing deviation and compromising the lumen. The philosophy that local anesthesia was the preferred method of analgesia when the airway was compromised still predominated. Even today, awake intubations are often used in this clinical setting.

Thyroid physiology

Throughout the nineteenth century, more attention was paid to the underlying physiology of the thyroid and its relationship to symptoms and surgical management. Leonardo Da Vinci, despite his anatomically correct drawings, incorrectly concluded that the purpose of the thyroid was to fill a void in the neck. Although there were many suggestions regarding the function of the thyroid, most physicians and surgeons believed there was no vital function to the gland. In 1884 Ludwig Rehn of Germany observed that the effects of thyroid toxicity, for which the thyroid was not yet credited, abated after thyroid removal for goiter. With this information, he suggested that an overproductive thyroid may be the cause of these symptoms. In 1888 William Greenfield noted that thyrotoxic symptoms correlated with thyroid gland hyperplasia. Others began noting similar relationships. Still, not until 1907 did Dr. Charles Mayo use the term hyperthyroidism, which he treated with thyroidectomy.

Patients who had total thyroidectomy often sustained the deleterious effects of too little thyroid hormone. In the 1880s, Kocher and others described and named the condition “cachexia thyreopriva.” Kocher argued against total thyroidectomy to avoid this complication. In his 1909 Nobel Prize acceptance speech for “his work in physiology, pathology, and surgery on the thyroid gland,” Kocher discussed the difficulties of recognizing thyroid disease more subtle than goiter, that is, hyper- and hypothyroidism. He noted that virtually any organ could be affected by alterations in thyroid function, and that the symptoms were often nonspecific. Recognizing the importance of adequate thyroid function and its influence on the “whole” patient was certainly in great contrast to the earlier belief that the thyroid may be functionless.

Advancements in microscopes and biochemical testing also evolved during the nineteenth century. The healthy and diseased thyroid could be observed at macro- and microscopic levels. Noting its ductless yet vesicle laden microarchitecture, scientists found evidence of chemical and colloid production. It was unclear what the thyroid produced or the mechanism of the production, although for centuries physicians had treated goiter with iodine-laden foods such as seaweed. Scientists began to realize that the thyroid stored and required iodine to produce “thyroid juice.” They also realized that post total thyroidectomy, symptoms could be avoided by supplying the patient with transplanted thyroid tissue, which some surgeons took to implant in patients who underwent total thyroidectomy. In time, oral supplements of desiccated animal thyroid extract replaced transplantation of exogenous tissue.

It was also observed that, if these thyroid masses could be treated with iodine, the gland would shrink, impinge less on the trachea, and subsequently lessen the demand for emergent goiter removal. Initially there were skeptics, including Billroth. He warned of the untoward consequences of “iodinism.” Over time, the physiologic relationship between exogenous iodine intake and thyroid function became evident, and with this medical treatment the prevalence of goiters declined.

The fields of thyroid gland surgery and physiology began to coalesce. It was recognized that a goiter was not the only thyroid abnormality requiring medical and surgical intervention. It became necessary to evaluate thyroid tissue preoperatively to determine management. Biopsy and cytology were means of accomplishing this. The first needles used to biopsy thyroid nodules were 2 to 4 mm in diameter and grooved for tissue sampling. The first known mention of tissue biopsy for microscopic evaluation was in 1847 by Kun of Strausburg, who sampled a subcutaneous nodule . The use of cytology rather than tissue biopsy for diagnosis began in the early 1900s but at that time focused on the evaluation of lymph nodes. In the 1920s, the Memorial Center of New York City used aspiration biopsy for diagnosis of a great number of tissue types with the exception of lymph nodes, salivary glands, and the thyroid. Distinguishing between nonanaplastic, dysplastic, and hyperplastic cells of nongoitrous thyroid disease via cytology was difficult, and needle puncture for this purpose did not enjoy popularity in the medical community . Over time, adequate sampling and cytologic evaluation of cellular characteristics permitted fine-needle aspiration to aid in surgical management.

Technology has brought new instrumentation to the field of thyroid gland surgery. The size of surgical incisions is becoming smaller, with minimally invasive thyroidectomy being the newest development in the field. In 1996 Gagner performed the first endoscopic thyroid procedure. In 1998 Miccoli introduced mini-invasive video-assisted thyroidectomy (MIVAT) that was initially reserved for the surgical treatment of goiters and papillary carcinomas less than 3 cm in diameter. Despite the restrictions of these procedures, attempts are continually being made to minimize the cosmetic effects of a neck scar while maintaining an acceptable mortality and morbidity.