He discovered them when he was dissect- ing a rhinoceros that had died in the London Zoo. The respective paper was eventually published in the Zoological Proceedings of London
Kocher and Billroth were the two exponents of thyroid surgery at the end of the nineteenth century. Each had founded a surgical school—Kocher in Bern and Billroth in Vienna—and the respective postoperative outcomes reflected the particular techniques utilized in each school. Kocher experienced the symptoms associated with radical removal of the thyroid, leading to postoperative hypothyroidism “cachexia strumipriva.” Billroth’s patients experienced tetany. Halsted gives another example of his surgical instinct when he associated these differences to the characters of operating surgeons: Kocher, neat and precise, operating in a relatively bloodless manner, scrupulously removed the entire thyroid gland, doing little damage outside the capsule. Billroth, operating more rapidly, and as I recall his manner, with less regard for tissues and less concern for hemorrhage, might easily have removed the parathyroids or at least interfered with their blood supply, and have left remnants of the thyroid.
Moreover, he could show that removal of the parathyroids alone would have the same effect. The concept of parathyroid transplantation was born 1892- He transplanted thyroid and parathyroid tissue into the preperitoneal space of cats and showed that tetany was absent and new vessels had formed at the transplants. In contrast, tetany occurred after these transplant were removed
Adolf Hansen developed a method for hormone extraction from bo- vine parathyroid glands. In animal experiments, these extracts were able to cure tetany and raise the serum calcium of parathyroprivic dogs. They also induced osteoporosis after administration over a prolonged period . These findings were substantiated with detailed experiments conducted by James P. Collip [6,7]. An immunoassay for parathyroid hormone de- tection in peripheral blood was developed by Yalow and Berson [4,58]. In
Master mariner of the U.S. merchant marine with transport duties in the North Atlantic. 1918, he was 22 years of age, about 1.85 m tall, and obviously in fine physical condition. A year later, Captain Martell’s disease became manifest with severe osteopathy and nephrolithiasis. In 1926 when Martell entered the Massachusetts General Hospital (MGH) for surgery, the patient had shrunk by about 18 cm. By this time he had experienced eight fractures and suffered from marked kyphosis and bone deformities. The two first cervical explorations done by Dr. E.P. Richardson were unsuccessful. A third operation was performed in 1932 by Dr. Russell Patterson in New York City, with no tumor being discovered, and Martell returned to the MGH. Dr. Oliver Cope and Dr. Edward D. Churchill performed three subsequent cervical reinterventions without finding an adenoma. The captain, who was often found in his room reading anatomy texts, was now convinced that the tumor was to be sought in the chest, and he urged a mediastinotomy. The seventh operation was per- formed by Churchill, with Cope’s assistance, and a mediastinal encapsulated brown tumor of 3 cm in diameter was found. The two surgeons excised only 90% of the adenoma, attaching the remnant with its vascular pedicle to the region of the sternal notch. Despite this, tetany developed three days after sur- gery. Six weeks postoperatively a kidney stone became impacted in the ureter and Captain Martell died from larnygospasm shortly after a surgical intervention to relieve his ureteral obstruction. After 1932, Cope and Churchill performed a number of successful parathyroidectomies.
The captain, who was often found in his room reading anatomy texts, was now convinced that the tumor was to be sought in the chest, and he urged a mediastinotomy. Six weeks postoperatively a kidney stone became impacted in the ureter and Captain Martell died from larnygospasm shortly after a surgical intervention to relieve his ureteral obstruction.
can be ascribed to the group around Fuller Albright who studied in detail the pathophysiology of parathyroid bone disease and recognized hyperparathyroidism as a distinct clinical syndrome.
This has provided surgery with a potent tool for preoperative imaging, useful both in primary and redo situations. A focused surgical access is possible thanks to preoperative scintigraphy and cervical ultrasonography. Quick methods for assess- ment of PTH emerged. In
Develop from the third and fourth pharyngeal (branchial)pouches Pharyngeal pouches develop in association with the aortic arches that encircle the developing foregut. The pharyngeal arches have a mesodermal core, covered on their superficial surface by ectoderm and on their deep surface by endoderm. The inferior parathyroid glands (parathyroid III) come from the third pharyngeal pouch and the supe- rior parathyroid glands (parathyroid IV) come from the fourth pharyngeal pouch. During the fifth week of development, the developing glands detach from the pouches and descend to join the thyroid gland during the seventh week. It should be noted that the inferior parathyroid glands actually arise from a more superior pharyngeal location (pouch III) than the superior thyroids (pouch IV). This relationship may be explained by the relationship of the developing inferior parathyroid gland with the thymus. The thymus arises from the caudal portion of the third pharyngeal pouch. As the thymus descends into the thorax, it is accompanied by the inferior parathyroid glands. Normally the attachment to the thymus is lost and the inferior parathyroid glands take up their normal position posterior to the thyroid. Sometimes, however, the inferior parathyroid glands are carried into the thorax along with the thymus. The ectopic parathyroid gland may be found in a number of locations (Table 2.1). The most common locations were intrathymic or par- aesophageal in the neck
2.4 Anatomy of the Parathyroid Glands There are normally two pairs of parathyroid glands, located along the posterior aspect of the thyroid gland (Fig. 2.7). The superior parathyroid glands normally lie at the level of the middle third of the thyroid, while the inferior parathyroid glands lie at the level of the inferior third. Generally, the superior parathyroid glands are supplied by the inferior thyroid artery, the 1718 superior thyroid artery, or both. Anastomotic con- nections within the thyroid allow both vessels to con- tribute, especially to the superior parathyroid glands. A number of methods have been advocated for local- izing the glands. These include ultrasonography , intraoperative methylene blue , and technetium sestamibi scans .
Nearby Relations of the Thyroid and Parathyroid at Risk During Surgery External Laryngeal Nerve The external laryngeal is a division of the superior la- ryngeal nerve, a branch of the vagus. This nerve sup- plies the cricothyroid muscle. Since this muscle is in- volved in movements of the vocal apparatus, damage to the nerve will impair phonation. The nerve may run near the superior pole of the thyroid on the wayto its target. The external laryngeal nerve is frequently entrapped in the vascular pedicle that transmits the superior thyroid vessels. Consequently the nerve may be injured during the ligation of these vessels [2,3]. 2.5.2 Recurrent Laryngeal Nerve The recurrent laryngeal nerve, a branch of the vagus, supplies the remainder of the laryngeal musculature as well as sensation on and inferior to the vocal folds (Figs. 2.2, 2.3). On the right side, the nerve loops pos- teriorly to the subclavian artery to ascend obliquely until it reaches the tracheoesophageal groove near the inferior extent of the thyroid (Fig. 2.7). On the left side the nerve loops posteriorly to the arch of the aorta and ascends to the larynx in the tracheoesophageal groove. The nerve may divide into a number of branches that also supply the trachea and esophagus . The nerve has a very close relationship with the inferior thyroid artery, where it might lie either an- teriorly or posteriorly to the vessel (Fig. 2.7). Because the left inferior thyroid artery may be absent in 6% of individuals, the identification of the recurrent la- ryngeal nerve may be more complicated . The nerve may also be closely related to or within the ligament of Berry. Care must be taken in both re- traction and division of the ligament to ensure that the nerve is preserved. There are some cases where the nerve may run through the substance of the gland [11,16]. In a small number of individuals (approximately 1%) the right subclavian artery arises distally from the arch of the aorta . As a consequence the right recurrent laryngeal nerve is not pulled into the tho- rax by its relationship with the subclavian artery. This non-recurrent right laryngeal nerve passes directly to the larynx posterior to the common carotid artery. It runs parallel to the inferior thyroid artery and can ascend for a short distance in the tracheoesophageal groove . It is, therefore, at risk for injury during surgery. The vagus nerve and sympathetic trunk are within or closely related to the carotid sheath (Figs. 2.2, 2.3, 2.8). The vagus nerve may receive some of its blood supply from the inferior thyroid artery . Conse- quently, the artery should not be ligated too close to its origin. Lymph node dissection along the carotid artery and near the vertebral artery or any manipu- lation near the superior pole of the thyroid gland should also be performed with care to ensure that the cervical sympathetic chain ganglia are not damaged or removed (Figs. 2.2, 2.3). Removal of large thyroid tumors may require divi- References sion of the infrahyoid muscles. Care must be taken to identify the branches of the ansa cervicalis that supply these muscles. The course of the ansa as it descends from the hypoglossal nerve is highly variable. Nor- mally, a superior division of the muscles will ensure the preservation of the nerve supply.
Maintenance of Calcium Homeostasis Parathyroid hormone and calcitriol act at the level of the gastrointestinal tract, bone, and the kidney to maintain circulating ionized calcium concentrations under extremely tight control, with a variation of <0.1 mg/dl, despite variations in calcium supply. Cal- cium consumption ranges from 400 to 2,000 mg daily . Due to the actions of calcitriol on the gut, net cal- cium absorption from the GI tract averages about 150 to 200 mg daily. At equilibrium, under the control of PTH and calcitriol, an equivalent amount of calcium is excreted by the kidneys. Calcium homeostasis in bone is regulated by PTH. PTH increases serum calcium by acting indirectly on the osteoclasts in the skeleton topromote bone resorption and thus release of calcium into extracellular fluid. Bone remodeling consumes and releases approximately 500 mg of calcium a day. If calcium intake or absorption is insufficient to meet demands, the large calcium reservoir in bone can be accessed to maintain extracellular calcium levels in a narrow range despite increased physiologic need or decreased intake. PTH also enhances calcium resorp- tion at the distal nephron of the kidney. In the kidney, PTH triggers production of calcitriol, which in turn increases fractional calcium absorption in the gut. If calcium intake increases beyond the body’s needs, PTH secretion decreases, leading to decreased cal- citriol production and decreased calcium absorption by the gut. If calcium is absorbed in excess of require- ments, it will be promptly excreted. Through this series of checks and balances, extracellular fluid ion- ized calcium concentration is carefully maintained, sometimes at the expense of skeletal calcium stores (Fig. 19.1). Disturbances of PTH or vitamin D will result in altered serum calcium concentration. Exam- ples of such pathologic processes will be discussed in the following sections. Calcium is essential to the functioning of a variety of processes throughout the body. including the contrac- tion of the heart and other muscles, the conduction of nervous impulses and other intracellular signals, the clotting of blood, and the secretion of glandular tis- sues. Precise maintenance of calcium concentration within a very narrow range in extracellular fluids is therefore critically important.
Primary hyperparathyroidism is one of the most common metabolic conditions requiring surgical in- tervention. Today, with automated blood chemistry panels having become a routine part of medical care, the most typical presentation is that of asymptomatic hypercalcemia. The individual found to have an elevated serum calcium level may have one of several conditions, however, and other potential causes must be carefully excluded before making a diagnosis of hyperparathyroidism and proceeding to any consid- eration of operative intervention.
100,000 new cases of 1 HPTH diagnosed each year although a variety of other symptoms may occur, which generally track in severity to the degree of serum calcium elevation
double adenoma adenoma”) are found, a frequency which may actu- ally be higher in the elderly. A very rare familial syndrome, the hyperparathyroidism–jaw tumor syndrome (HPTH-JT) is another autosomal dominant inherited condition presenting with early-onset primary HPTH and fibro-osseous, cystic jaw neoplasms Several kindreds with familial isolated primary HPTH have also been described, outside of MEN1, MEN2A, A very rare familial syndrome, the hyperparathyroidism–jaw tumor syndrome (HPTH-JT) is another autosomal dominant inherited condition presenting with early-onset primary HPTH and fibro-osseous, cystic jaw neoplasms Several kindreds with familial isolated primary HPTH have also been described, outside of MEN1, MEN2A,
Although FHH is generally classified in the “parathyroid mediated” category of hypercalcemia since parathyroid hormone secretion is abnormal, it is clearly a unique disease and distinct from primary HPTH. In- deed, parathyroidectomy will not cure the condition. Distinguishing those patients with drug-induced hy- percalcemia from those with mild primary HPTH can be challenging. Finally, chronic lithium therapy may increase serum calcium levels with inappropriately normal or mildly elevated PTH concentrations. Lithium appears to al- ter the sensitivity of the CaSR . As a result, the extracellular calcium set-point for PTH release is increased. Parathyroid adenomas have also been de- scribed in patients chronically treated with lithium.
Finally, chronic lithium therapy may increase serum calcium levels with inappropriately normal or mildly elevated PTH concentrations. Lithium appears to al- ter the sensitivity of the CaSR . As a result, the extracellular calcium set-point for PTH release is increased. Parathyroid adenomas have also been de- scribed in patients chronically treated with lithium.
If this is done by an experienced parathyroid surgeon, parathyroidectomy may be curative in over 95% of cases. For many decades, routine preoperative localization was not regarded as standard of care for primary HPTH The choice of modality further depends on what instrumentation is available, the experience of both the examiners and the interpreters of the examinations, and where the lesion is most likely to be. It also depends on the setting when localization tests are performed for pri- mary or reoperative cases. Allowing a targeted excision of a single parathyroid adenoma, resulting a smaller incision, shorter surgical time often performed as an outpatient employing the use of local rather than general anesthesia, and substantially reducing the risk of damage to the recurrent laryngeal nerve
The premise of this combination imaging is that thal- lium (a potassium analogue) is taken up by both the thyroid and the parathyroid glands, whereas the pertechnetate is taken up only by the thyroid gland. Taking advantage of the built-in multichannel ana- lyzers of present-day gamma cameras, photons from the decays of both isotopes can be registered simul- taneously using different energy windows for each of the radioisotopes. However, the photo peak from 201Tl (69–83 keV) is much lower than that from 99mTc (140 keV), which will result in “spill down” phenome- non from 99mTc photons into the energy window used for 201Tl centered at 80 keV. Another technical obsta- cle is that due to the relatively long physical half-life of 201Tl at 73 h, the typical dose used is 2–4 mCi (equiv- alent to 74–148 MBq), which will not afford any op- portunities for quality tomographic imaging. Hence, this combination imaging is limited to the use of pla- nar views using a converging or a pinhole collimator. Due to the low dose of 201Tl used, imaging time is of- ten long and increases the risk for patient movement artifacts, which can severely compromise the quality of the images. In addition to the simultaneous acqui- sition using multiple energy windows, a subtraction program will also need to be implemented to demon- strate differential accumulation of both radiotracers. Although the technique provides useful information, without tomographic imaging, the precise location of the adenoma cannot be obtained. While sensitivities of 85–95% have been reported , many practitio- ners concede that the sensitivity is much lower for hy- perplastic glands as compared to primary adenomas as well as for glands under 300 mg in weight [9,10]. While the most common false-positive finding is solid thyroid nodule(s), whether solitary or multinodular in nature, other medical conditions such as sarcoid- osis , thyroid carcinoma , and lymphoma  have also been described. 3rd- with the aid computer program, this technique can enhance the contrast between a parathyroid adenoma and the thyroid gland.
However, the larger a para- thyroid adenoma grows, the more irregular the shape will become. Cystic degeneration and calcification are uncommon findings. Adenomas are typically quite vascular with a very specific pattern of blood flow. A feeding artery, usually a branch of the inferior or su- perior thyroid artery, can often be followed directly into either the upper or lower pole of the adenoma, so Unique role in preoperative fine-needle aspiration (FNA) of extrathyroidal masses to confirm the diagnosis of a parathyroid adenoma, particularly in patients with recurrent HPTH following a failed neck exploration. less expensive, move readily available, and does not expose the patient to ionizing radiation. However, US examination is quite operator dependent and the reported sensitivities of US for ac- curately localizing parathyroid adenomas have ranged from 34 to 92% (averaging in the 60–80% range)
glands usually lie within the fat-replaced thymus, and even small adenomas may readily be visualized MRI resolution with T1-weighted images (Fig. 20.11) of parathyroid adenomas is comparable to that of CT scans, with a low to intermediate signal intensity sim- ilar to that of muscle on T1-weighted images. On the other hand, T2-weighted images (Fig. 20.12) or short- tau inversion recovery-pulse sequences produces a bright signal Re- ported sensitivities for parathyroid gland localization by MRI are 71–83%. Sensitivity is supe- rior
It can not give the exact height and location of an adenoma or hyperplasia, distinguish between the two, or directly “show” the offending lesion. Unlike imaging tests, its accuracy is not dependent on lesion size, but rather PTH output.
Single Adenoma- If an enlarged parathyroid gland appears fibrotic, elicits a desmoplastic reaction, and is adherent to other neck structures or the thyroid gland, clini- cal suspicion should be raised of parathyroid malig- nancy, and the gland should be resected en bloc with a hemithyroidectomy. If lymphadenopathy is noted, a central lymph node dissection on the ipsilateral side should be undertaken. Frozen section of the parathy- roid gland is rarely helpful in confirming a clinical suspicion of malignancy. At no time should the sur- geon cut across a suspicious gland in order to obtain a frozen section to confirm parathyroid carcinoma.
3rd- whereby three and a half glands are removed, should be performed. Cryopreservation of one gland, which can be stored indefinitely, should be planned, if this modality is available, as this will reduce the potential for permanent hypoparathyroidism, allowing trans- plantation at a later date
Incomplete re- section of diseased parathyroid tissue causes persis- tence of hypercalcemia and primary HPTH, while unnecessary resection of normal parathyroid glands may cause permanent hypoparathyroidism. The use of intraoperative PTH assays may aid in guiding the extent of parathyroidectomy. “ hyperplasia theory” recommend subtotal parathyroidectomy (resection of three and a half glands) or total parathyroidectomy with auto- transplantation. Surgeons who consider the double adenomas to be a separate disease entity, remove only the clinically enlarged glands. All of these procedures require four-gland exploration
The incidence of primary HPTH is increasing. While new technologies are enabling preoperative localiza- tion of parathyroid gland pathology and the removal of solitary adenomas with minimally invasive ap- proaches, the success of parathyroidectomy remains dependent upon a thorough understanding of the embryology and anatomy of the neck. This is achiev- able only by the surgeons’ experience and intimate knowledge of the traditional bilateral neck explora- tion. although successful resection of these adenomas using video-assisted thoracoscopic surgery (VATS) is becoming more popular If the adenoma cannot be identified at the time of the neck exploration and the patient has persistent HPTH, additional imaging techniques, such as thorough neck ultrasonography with the primary potential fine-needle aspiration identification of parathyroid glands, neck and chest MRI or CT scan, sestamibi with SPECT, or selective jugular venous sampling for a PTH differential gradi- ent may need to be employed in order to localize the ectopic glands.
3- If both an enlarged and normal gland were found on the initial side, then contralateral exploration was aborted. which they defined as removal of both an adenoma and normal gland from one side . 4- Both techniques would fail, however, in the setting of a double adenoma on the contralateral side and if the essentially “random”choice of which side to explore was incorrect. Today, minimally invasive parathyroidectomy (MIP) is per- formed after preoperative parathyroid localization usually with high-quality sestamibi scans, often un- der cervical block anesthesia during which a limited exploration is performed, and the rapid intraopera- tive parathyroid hormone (PTH) assay is employed to confirm an adequate resection
(to capture a potential spike compared with the preoperative baseline caused by manipulation of the gland during exploration), and These proto- cols have been designed to account for the half-life of PTH, which is 2–4 minutes, and to avoid misleading results caused by a spike in PTH that may occur dur- ing mobilization of the adenoma Although the assay has not been designated for use with tissue aspirates, samples can be collected by as- piration of the tissue in question with a syringe con- taining 1 ml saline solution and then injection of the saline into ethylenediaminetetraacetic acid (EDTA) tubes for analysis. rapid assay is also especially helpful when the surgeon or pathologist has difficulty distinguish- ing between thyroid tissue, lymph nodes, or a para- thyroid adenoma. Aspiration of parathyroid tissue yields substantially higher hormone values than the upper limit of the standard curve; values greater than 1,500 pg/ml secure the tissue diagnosis, and there is minimal incremental cost in cases where the intra- operative PTH assay is being utilized already Operative failure rates for initial and reoperative parathyroidectomy appear to have decreased signifi- cantly with this intraoperative adjunct. Irvin demon- strated that operative failure rates from initial para- thyroidectomy have significantly decreased with the advent of the rapid PTH assay, from 6% to 1.5%
The operation, although successful, raised a certain degree of scepticism, in particular among endocrine surgeons, probably because the indication was not adequate for such a procedure Main advantage: cosmetic benefit