The anatomic basis of parathyroid surgery

Endoscopic total parathyroidectomy and partial parathyroid tissue autotransplantation for patients with secondary hyperparathyroidism: a new surgical approach

Background

Secondary hyperparathyroidism (SHPT) (i.e., renal hyperparathyroidism) is one of the most serious complications in long-term hemodialysis patients. The purpose of this retrospective study was to explore the feasibility of a new surgical approach—endoscopic total parathyroidectomy with autotransplantation (ETP+AT)—and evaluate its practical application for patients with SHPT.

Methods

The study included 34 SHPT patients who underwent ETP+AT from among 67 cases at the Department of Minimally Invasive Surgery, the First Affiliated Hospital of Nanjing Medical University over a 3-year period. The other 33 patients underwent traditional total parathyroidectomy with autotransplantation (TP+AT). Two criteria were used as indications to perform ETP+AT in SHPT patients. The first was a high serum parathyroid hormone level (PTH >800 pg/ml) associated with hypercalcemia and/or hyperphosphatemia that which were refractory to medical treatment. The second criterion was the presence of clinical symptoms including pruritus, bone and joint pain, muscle weakness, progression of soft tissue calcification, and spontaneous fractures. Ultrasonography, ^99mTc sestamibi scans, and computed tomography were used to evaluate the thyroid and parathyroid glands.

Results

There was no surgery-related mortality among any of the patients with ETP+AT. One patient underwent conventional neck exploration because of bleeding and injury of a unilateral recurrent laryngeal nerve after the operation. Preoperative symptoms were alleviated, and the serum PTH and alkaline phosphatase levels, hyperphosphatemia, and hypercalcemia were improved or normalized in most patients. Recurrence was observed in one patient with a sixth parathyroid gland behind his thyroid, and the patient required a second operation. Hypoparathyroidism was not found after the operation. The clinical data were compared between ETP+AT and TP+AT.

Conclusions

ETP+AT is a safe option for the treatment of SHPT with low morbidity and mortality, shorter hospital stay and low recurrence rate. It is important to avoid intraoperative bleeding, identify all parathyroid glands during the surgery, and choose adequate parathyroid tissues for autografting.

The fallen one: the inferior parathyroid gland that descends into the mediastinum

BACKGROUND

Inferior parathyroid glands are located along the embryologic migration path of the thymus and can rest in the thyrothymic ligament or anterior mediastinum. Our nomenclature system designates these glands as "fallen" (type F) glands. This study reviews our experience with type F parathyroid glands to determine which can be retrieved successfully through a cervical incision.

STUDY DESIGN

A retrospective review of patients who underwent parathyroidectomy between June 1998 and May 2008 was performed. Patient demographics, localization studies, and operative and pathologic reports were analyzed. Distance from the superior aspect of the clavicle to the target parathyroid gland was measured.

RESULTS

Sixty (9.2%) patients had a type F parathyroid gland. Parathyroidectomy was performed through cervical incision in 54 (90%) patients and 6 (10%) required a thoracic approach. Preoperative imaging identified parathyroid glands located >or=6 cm below the superior aspect of the clavicle in eight patients. Of these, six (75%) required a thoracic approach and two (25%) were resected through a cervical incision with concomitant thymectomy. Parathyroidectomy was successfully performed through a cervical incision in all 52 (100%) patients in whom the target parathyroid gland was <6 cm below the superior aspect of the clavicle (Fisher's exact test, p < 0.001).

CONCLUSIONS

A cervical approach allows successful retrieval of type F parathyroid glands located <6 cm below the superior aspect of the head of the clavicle in the anterior mediastinum. Parathyroidectomy for glands located >or=6 cm below the superior aspect of the clavicle can be attempted from the neck with concomitant thymectomy, but the majority will require a thoracic approach.

Long-term treatment with cinacalcet and conventional therapy reduces parathyroid hyperplasia in severe secondary hyperparathyroidism

BACKGROUND

The effect of cinacalcet on the structural pattern of hyperplastic parathyroid glands was evaluated, using high-resolution colour Doppler (CD) sonography, in haemodialysis patients with severe, inadequately controlled, secondary hyperparathyroidism (sHPT).

METHODS

Nine patients (6 males, 3 females; mean age +/- SD, 55.5 +/- 12.6 years) received cinacalcet, with adaptation of existing concomitant therapies. Biochemical parameters and the morphology and vascular pattern of hyperplastic parathyroid glands were measured at baseline and every 6 months thereafter, for a follow-up period of 24-30 months.

RESULTS

At baseline, 28 hyperplastic glands were identified. Cinacalcet led to a reduction in glandular volume during the course of the study: 68% in glands with a baseline volume <500 mm(3) and 54% in glands with a baseline volume >or=500 mm(3). The mean volume +/- SD of glands <500 mm(3) changed significantly from the baseline (233 +/- 115 mm(3)) to the end of follow-up (102 +/- 132 mm(3), P = 0.007). Levels of mean serum phosphorus, calcium and calcium-phosphorus product decreased, but not significantly, whereas there were significant decreases in mean parathyroid hormone +/- SD levels (1196 +/- 381 pg/ml versus 256 +/- 160 pg/ml; P < 0.0001) and alkaline phosphatase +/- SD levels (428 +/- 294 versus 223 +/- 88 IU/l; P = 0.04), accompanied by an improvement in a subjective clinical score.

CONCLUSIONS

Cinacalcet, in combination with conventional treatments, led to an improvement in biochemical and clinical parameters of sHPT and reduced glandular volume in patients with severe sHPT. Volume reduction was more evident in smaller glands. Longer term, larger, randomized clinical trials are needed to confirm these preliminary findings and to further define a more systematic approach in the treatment of sHPT.

Incidence of parathyroid glands located in thymus in patients with renal hyperparathyroidism

BACKGROUND

Parathyroid glands are frequently located in thymus, and it is essential to resect thymic tissue from the neck incision, especially in surgery for renal hyperparathyroidism (HPT).

METHODS

In this study, we evaluated the incidence, location, and type of intrathymic parathyroid glands in 902 patients who underwent initial parathyroidectomy (PTx) for advanced renal HPT in our department. Removal of the thymic tongues on both sides was routinely performed from the neck incision, and the thymic tissue was carefully examined both macroscopically and microscopically.

RESULTS

Of the 902 patients in the study, 269 had only inferior parathyroid glands in the thymus, in 62 patients only supernumerary glands were found in the thymic tongue, and in 78 patients both inferior and supernumerary glands were present in thymic tissue. Therefore the incidence of patients with intrathymic glands was 45.3% (269 + 62 + 78 = 409/902). In 129 (92.1%) of 140 patients with supernumerary glands in the thymic tongue, these glands were detected only on histopathological examination, and about half of them were classified as the parathyromatosis type.

CONCLUSIONS

In the human, parathyroid glands might be located in the thymus in about 50%. If the inferior gland/glands cannot be found around the inferior pole of thyroid lobe, it is very important to search for glands in the thymic tongue. Moreover, to avoid missing supernumerary glands, removal of the thymic tongue on both sides is essential in surgery for renal HPT.

Impact of adenoma weight and ectopic location of parathyroid adenoma on localization study results

Although the sensitivity of preoperative localization techniques is high for solitary parathyroid adenomas, negative imaging study results are inevitable. The weight and location of the parathyroid adenoma may contribute to the negative results. We aimed to study the impact of adenoma weight and ectopic location of the parathyroid adenoma on ultrasonography and sestamibi scan results. The patients were divided into two groups according to adenoma location. Group 1 consisted of 36 patients with ectopic location, and group 2 consisted of 149 patients with normal location. Parathyroid adenoma weight and the results of imaging studies were determined in all patients. Of 185 patients operated on for hyperparathyroidism, 36 (19.4%) had ectopic parathyroid glands. There was a positive correlation between adenoma weight and positive imaging studies, whereas ectopic location did not correlate with negative imaging study results. There was no significant difference between the ectopic adenoma ratio of patients with negative and positive imaging study results. The weight of the ectopic parathyroid adenoma was significantly lower in patients with negative imaging study results than in patients with positive imaging study results (p = 0.001). According to the analysis of variance, patients with higher-weight adenomas have positive imaging study results irrespective of ectopic location. For both normal and ectopic adenoma locations, adenoma weight was found only to be a factor that positively influences imaging study results.

Vocal fold paresis and paralysis: what the thyroid surgeon should know

The thyroid surgeon must have a thorough understanding of laryngeal neuroanatomy and be able to recognize symptoms of vocal fold paresis and paralysis. Neuropraxia may occur even with excellent surgical technique. Patients should be counseled appropriately, particularly if they are professional voice users. Preoperative or early postoperative changes in voice, swallowing, and airway function should prompt immediate referral to an otolaryngologist. Early recognition and treatment may avoid the development of complications and improve patient quality of life.

Value of Sestamibi Scans in Tertiary Hyperparathyroidism

OBJECTIVES

To determine the value of preoperative Tc-sestamibi scans and the incidence of ectopic glands in tertiary hyperparathyroidism.

DESIGN

Prospective, non-randomized analysis of a consecutive cohort of surgical patients from the Medical College of Georgia Thyroid/Parathyroid Center.

MATERIALS AND METHODS

A consecutive series of patients with tertiary hyperparathyroidism undergoing parathyroidectomy was analyzed. Demographic data, preoperative Tc-sestamibi scintigraphy results, location of diseased glands, pre- and postoperative calcium, and parathyroid hormone levels were collected.

RESULTS

Twenty-one patients underwent parathyroidectomy for tertiary hyperparathyroidism between March 2004 and September 2006. Of these 21 patients, 3 were re-operative cases for persistent hypercalcemia and each was found to have a single diseased gland. Of the 18 patients undergoing first time surgery, 15 had four-gland hyperplasia, 2 patients had single adenomas, and 1 patient had a double adenoma. Nine of the 21 patients (43%) had ectopic glands (2 of these patients had 2 ectopic glands each). The overall sensitivity of the preoperative Tc-sestamibi scintigraphy was 76% and was not significantly different when comparing patients with ectopic glands (78%) and those without (75%).

CONCLUSIONS

Tc sestamibi scintigraphy has high positive predictive value and sensitivity in patients with tertiary hyperparathyroidism. Sestamibi scanning is particularly valuable in this patient population since the incidence of ectopic glands may be higher than previously recognized.

Parathyroid imaging: technique and role in the preoperative evaluation of primary hyperparathyroidism

OBJECTIVE

This article discusses the commonly used techniques for imaging the parathyroid glands and their role in the preoperative evaluation of patients with primary hyperparathyroidism.

CONCLUSION

The importance of sonography and sestamibi scintigraphy in the preoperative evaluation of patients with primary hyperthyroidism has increased with the adoption of minimally invasive parathyroidectomy techniques at most medical centers. When the results of these studies are concordant, the cure rates of minimally invasive surgery equal those of traditional bilateral neck exploration.

Parathyroid sonography: imaging and intervention

This article reviews the role of high-resolution sonography as an imaging modality for the diagnosis and treatment of patients with parathyroid disease. Included is a discussion of sonographic anatomy and technique, disease processes of the parathyroid glands and their sonographic appearances, preoperative imaging, and the use of sonography as a guide for diagnostic and therapeutic intervention in parathyroid disease.

Cervical thymectomy for intrathymic parathyroid adenomas during minimally invasive parathyroidectomy

BACKGROUND

The development of an intrathymic parathyroid adenoma is common, and thymectomy is a significant component of the parathyroid surgeon's technical armamentarium. Over the last decade, minimally invasive parathyroidectomy (MIP) has become the standard technique for removal of an abnormal parathyroid gland, and the requirement for thymectomy should remain unchanged during the era of minimally invasive techniques. The aim of this paper was to assess the feasibility and outcomes of cervical thymectomy for intrathymic parathyroid adenomas during MIP.

METHODS

This is a retrospective case series. The study group comprised all patients undergoing parathyroidectomy in the University of Sydney Endocrine Surgical Unit during a 5-year period (January 2001 to December 2005). Patients undergoing MIP and open parathyroidectomy with a concomitant cervical thymectomy were compared.

RESULTS

A total of 840 patients underwent parathyroid surgery for primary hyperparathyroidism (PHPT) during this period. A total of 30 MIP procedures with concurrent thymectomy were performed, and 99 open bilateral neck explorations with cervical thymectomy were performed. Of the MIP thymectomy group, there were 25 female and 5 male patients; the average age was 57 years (range, 22 to 82). A mean length of 34 mm of thymus was extracted via the minimally invasive approach (range, 8 to 85 mm). In 5 cases, only fatty tissue was identified histologically, and, in 5 cases, a small supernumerary parathyroid gland was identified in the histologic specimen. Only 1 patient suffered temporary, recurrent laryngeal nerve palsy; there were no cases of postoperative hemorrhage requiring return to the operating room.

CONCLUSIONS

Cervical thymectomy for removal of intrathymic parathyroid adenomas can be performed during lateral focused mini-incision MIP with a safety and efficacy equivalent to open bilateral neck explorations.

Partial median sternotomy: an attractive approach to mediastinal parathyroid disease

BACKGROUND

Parathyroid exploration through a standard cervical approach is adequate for the resection of most mediastinal parathyroid glands. A subset of mediastinal parathyroid glands causing hyperparathyroidism, however, cannot be removed in this manner.

STUDY DESIGN

We reviewed our experience with the use of partial median sternotomy in the treatment of these patients.

RESULTS

Over a 14-year period, all but 10 of 937 (1.1%) consecutive patients explored for hyperparathyroidism by a single endocrine surgeon were treated by a cervical approach. Partial median sternotomy was performed in 10 cases and was successful in seven cases (70%), with conversion to a complete sternotomy being required in three cases. Six of these seven patients had failed a previous parathyroid exploration (86%), including one patient who had a previous complete sternotomy. Cure of hyperparathyroidism was achieved in all seven patients undergoing partial median sternotomy. In five patients a mediastinal parathyroid gland was removed (71%), and in one patient a parathyroid adenoma in the carotid sheath was eventually found, and the location of the hyperfunctioning parathyroid gland in one patient was never determined although the patient was cured. The mean length of hospital stay after a partial median sternotomy was 2.6 days. One patient sustained a recurrent laryngeal nerve injury at the time of a repeat cervical exploration and partial median sternotomy.

CONCLUSIONS

Rarely, mediastinal parathyroid glands cannot be resected through a cervical approach. In these cases the use of partial median sternotomy is an attractive technique in achieving cure of hyperparathyroidism and is associated with minimal morbidity and a short length of hospital stay.

The diagnosis and management of asymptomatic primary hyperparathyroidism

Classical primary hyperparathyroidism--a disease of 'bones, stones, and psychic groans'--is a rarity in the US, although it is still seen in some parts of the world. Today, most patients with primary hyperparathyroidism are asymptomatic. This change in clinical profile is not merely because of improved detection techniques, and patients with primary hyperparathyroidism who lack symptoms, if left untreated, rarely develop the 'classical' features that were common previously. Indeed, currently available data suggest that there is, today, a disorder with different, yet characteristic, effects on the end-organs of the hyperparathyroid process. In this review, the features of the skeletal, renal, neuropsychologic, cardiovascular, and gastrointestinal manifestations of 'asymptomatic' primary hyperparathyroidism will be discussed. The considerable body of data that has emerged since the recognition of the new clinical profile of primary hyperparathyroidism has allowed a reconsideration of standards of care for this disease. These data were reviewed and incorporated into new clinical guidelines at the 2002 NIH workshop on asymptomatic primary hyperparathyroidism. These recommendations highlight both what is known about the disease, and important areas that need investigation. Continued interest in the skeletal, cardiovascular, and neuropsychiatric manifestations of the disease, and therapeutic trials of medical approaches for its management, will further refine our current understanding, and could lead to additional modifications in the approach to patients with this common endocrine disorder.

Two Hundred Consecutive Parathyroid Ultrasound Studies by a Single Clinician: The Impact of Experience

OBJECTIVE

To assess the ability of ultrasound studies, performed by an experienced clinician, to predict surgical findings and provide precise anatomic localization of abnormal parathyroid glands.

METHODS

We retrospectively examined 200 consecutive parathyroid ultrasound studies performed by a single experienced clinician in our unit. All patients subsequently underwent parathyroidectomy, with histopathologic confirmation of abnormal parathyroid tissue. The correlation between the ultrasound and surgical findings was assessed.

RESULTS

Of the 200 study patients, 197 (98.5%) were cured of their disease at the initial operation. Ultrasound studies correctly predicted the surgical findings in 88% of patients, including 168 of 180 (93%) with single gland disease and 7 of 20 (35%) with multiple gland disease (MGD). In all cases in which a single adenoma was identified, precise information regarding its location relative to adjacent anatomic structures was provided. In 92% of these cases, anatomic details correlated closely with surgical findings. Ectopic and descended superior adenomas were most frequently missed. Patients with two nonlocalizing studies (scintigraphy and ultrasonography) had a >50% likelihood of having MGD.

CONCLUSION

In experienced hands, parathyroid ultrasonography is a highly sensitive technique that provides both localization of enlarged parathyroid glands and precise anatomic detail. Thus, in this study, focused parathyroidectomy was possible in 76.5% of patients. MGD remains difficult to diagnose preoperatively. Nonlocalizing studies should alert the surgeon to a high probability of MGD and prompt the performance of 4-gland exploration.

Incidence and location of ectopic abnormal parathyroid glands

BACKGROUND

Ectopic parathyroid glands are a cause for failed parathyroid exploration.

METHODS

Patients with hyperparathyroidism and ectopic parathyroid glands were identified from a parathyroid database. Laboratory data, gland weights, and surgical outcomes were obtained. The locations of the ectopic glands were correlated with results of technetium-99m-sestamibi imaging.

RESULTS

Of 231 patients operated on for hyperparathyroidism, 37 (16%) had ectopic parathyroid glands. Ectopic inferior glands (N = 23 [62%]) were intrathymic, n = 7 (30%); anterosuperior mediastinal, n = 5 (22%); intrathyroidal, n = 5 (22%); within the thyrothymic ligament, n = 4 (17%); and submandibular, n = 2 (9%). Ectopic superior glands (N = 14 [38%]) were in the tracheoesophageal groove, n = 6 (43%); retroesophageal, n = 3 (22%); posterosuperior mediastinal, n = 2 (14%); intrathyroidal, n = 1 (7%); in the carotid sheath, n = 1 (7%); and paraesophageal, n = 1 (7%). Sestamibi scans were true-positive in 81%, identifying 13 of 16 retrosternal glands, and false-negative in 19%.

CONCLUSIONS

A 16% incidence of ectopic parathyroid glands and a 100% positive predictive value of sestamibi scintigraphy underscore the importance of sestamibi imaging in patients with primary hyperparathyroidism.

Twice-Recurrent Primary Hyperparathyroidism Due to Parathyroid Hyperplasia in an Ectopic Supernumerary Gland

OBJECTIVE

To describe a patient with multiple recurrences of primary hyperparathyroidism during a 24-year period.

METHODS

We present the long-term history, including clinical and laboratory evaluations as well as findings on surgical interventions, in a 42-year-old man with recurrent hyperparathyroidism. In addition, the relevant literature is briefly reviewed.

RESULTS

At initial surgical exploration when the patient was 18 years old, a single enlarged parathyroid gland and a normal-appearing ipsilateral gland were found. After more than a decade without symptoms, the patient experienced recurrent symptomatic hypercalcemia. Surgical exploration revealed symmetric multiglandular disease that was treated by resection of 3 enlarged parathyroid glands and implantation of a portion of 1 gland in the forearm. After another 6-year asymptomatic period, the patient had recurrent symptoms and was found to have recurrent hypercalcemia. Surgical intervention revealed an enlarged supernumerary gland in an ectopic location. A preoperative technetium Tc 99m sestamibi scan and intravenous administration of methylene blue were helpful in identifying the ectopic parathyroid gland in the left carotid sheath.

CONCLUSION

This case illustrates the difficulty of determining which of a patient's parathyroid glands may become hyperfunctioning and the importance of considering whether supernumerary glands may be present. The case also demonstrates the need for long-term follow-up before a patient is considered "cured" of hyperparathyroidism.

Radionuclide imaging of the parathyroid glands

The parathyroid glands, which usually are situated behind the thyroid gland, secrete parathyroid hormone, or PTH, which helps maintain calcium homeostasis. Primary hyperparathyroidism results from excess parathyroid hormone secretion. In secondary hyperparathyroidism, the normal PTH effect on bone calcium release is lost. Serum PTH rises, causing generalized hyperplasia. In tertiary hyperparathyroidism, a complication of secondary hyperparathyroidism, normal feedback mechanisms governing PTH secretion are lost, parathyroid gland sensitivity to PTH decreases, and the threshold for inhibiting PTH secretion increases. 99mTc sestamibi, or MIBI, the current radionuclide study of choice for preoperative parathyroid localization, can be performed in various ways. The "single-isotope, double-phase technique" is based on the fact that MIBI washes out more rapidly from the thyroid than from abnormal parathyroid tissue. However, not all parathyroid lesions retain MIBI and not all thyroid tissue washes out quickly, and subtraction imaging is helpful. Many MIBI avid thyroid lesions also accumulate pertechnetate and iodine, and subtraction reduces false positives. Single-photon emission computed tomography provides information for localizing parathyroid lesions, differentiating thyroid from parathyroid lesions, and detecting and localizing ectopic parathyroid lesions. The most frequent cause of false-positive MIBI results is the solid thyroid nodule. Other causes include thyroid carcinoma, lymphoma, and lymphadenopathy. False-negative results occur because of several factors. Lesion size is important. Cellular function also may be important. Parathyroid tissue that expresses P-glycoprotein does not accumulate MIBI. Parathyroid adenomas that express either P-glycoprotein or the multidrug resistance related protein MRP are less likely to accumulate MIBI. MIBI scintigraphy is less sensitive for detecting hyperplastic parathyroid glands. In secondary hyperparathyroidism, MIBI uptake is more closely related to cell cycle than to gland size. Mitochondria-rich oxyphil cells presumably account for MIBI uptake in parathyroid lesions. Fewer oxyphil cells, and hence fewer mitochondria, may explain both lower uptake and rapid washout of MIBI from some lesions. MIBI is also less sensitive for detecting multigland disease than solitary gland disease.

Inframanubrial parathyroid glands in patients with primary hyperparathyroidism: alternatives to sternotomy

Deep inframanubrial parathyroid tumors have traditionally been excised through a median sternotomy. With the advent of minimally invasive surgical access, we chose to examine the treatment options and outcomes of patients with inframanubrial mediastinal parathyroid tumors. Patients with primary hyperparathyroidism seen at a university medical center over a 12-year period were retrospectively reviewed. The utility of localization studies, methods of treatment, complications, and outcomes were examined in patients with a parathyroid tumor located in the mediastinum inferior to the manubrium. Patients with parathyroid adenomas located at the thoracic inlet were excluded. Sixteen patients with inframanubrial mediastinal tumors were treated during the study period. Altogether, 81% of the patients had undergone at least one prior neck exploration for primary hyperparathyroidism. Preoperative calcium and parathyroid hormone levels were 12.4 +/- 0.36 mg/dl and 273 +/- 70 pg/ml, respectively. Localization studies identified mediastinal parathyroid adenomas in the following locations: anterior mediastinum (n = 8), middle mediastinum (n = 7), posterior mediastinum (n = 1). Mediastinal computed tomography and technetium-sestamibi scans demonstrated the best sensitivity, 92% and 85%, respectively. Seven patients underwent successful excision of the mediastinal adenoma by transcervical mediastinal exploration with the Cooper retractor. The other patients underwent angiographic ablation (n = 4), anterior mediastinotomy (n = 3), video-assisted thoracoscopy (VATS) (n = 1), and VATS plus thoracotomy (n = 1). The mean hospital stay for the study group was 2.9 +/- 0.7 days. The complication rate was 25%. All patients were normocalcemic after a mean follow-up of 15 +/- 7 months. Most inframanubrial mediastinal parathyroid tumors can be successfully managed without median sternotomy.

Four gland parathyroidectomy without reimplantation in patients with chronic renal failure

BACKGROUND

The optimal surgical management of patients in end stage chronic renal failure with secondary hyperparathyroidism is controversial. One approach advocated is four gland parathyroidectomy without reimplantation. The aim of this study was to review the medium term results of this procedure.

METHODS

Fifty four consecutive patients with end stage chronic renal failure and secondary hyperparathyroidism who had a four gland parathyroidectomy without reimplantation were studied. The procedure was performed by a single surgeon with a median (range) follow up of 29 (0-70) months.

RESULTS

Most patients (76%) developed postoperative hypocalcaemia but this was easily treated and doses of long term drugs necessary to prevent this were low. Pre-operative bone symptoms, hypercalcaemia, hyperphosphataemia, and an increased alkaline phosphatase were improved or resolved in most patients. Thirteen (24%) patients had an undetectable postoperative parathyroid hormone (PTH), (6 of 12 (50%) with a functioning renal transplant and 7 of 42 (17%) who required dialysis, p = 0.02). Median (range) postoperative PTH values in these groups were 0.1 (0.1-31) compared with 1.0 (0.1-24) pmol/l (p = 0.085) respectively. The remaining 41 of 54 (76%) patients had residual PTH secretion and postoperative hyperparathyroidism was identified in eight (15%) patients with only two requiring neck re-exploration.

CONCLUSION

Four gland parathyroidectomy without reimplantation produced good medium term biochemical and clinical results. Most patients had minor residual PTH secretion that may contribute to this and mitigate concerns regarding adynamic bone disease. Endogenous PTH secretion is only completely lost in a few patients but occurs more often in those with a functioning renal transplant. Bone densitometry is required to investigate the long term impact of this procedure.

The Scintigraphic Appearance of Subcapsular Parathyroid Adenomas

PURPOSE

Approximately 5 to 10% of parathyroid adenomas are located within the thin, fibrous capsule of the thyroid gland. These subcapsular adenomas can complicate minimally invasive parathyroidectomy. The small incision used in this procedure limits the view of the surgical bed. Palpation is less sensitive when the adenoma is covered by the thyroid capsule. If a subcapsular parathyroid adenoma can be identified on preoperative parathyroid scintigraphy, nuclear medicine physicians can recommend exploration of the thyroid capsule early, leading to an easier, more efficient operation. The objective of this observational study was to identify the scintigraphic appearance of subcapsular parathyroid adenomas.

MATERIALS AND METHODS

A total of 109 patients with primary hyperparathyroidism underwent preoperative dual-phase Tc-99m sestamibi parathyroid scintigraphy at our tertiary care center from October 2002 to March 2004. Tc-99m pertechnetate was used as a supplemental technique when deemed necessary for optimal interpretation. Retrospective chart review identified 16 surgically proved subcapsular parathyroid adenomas. Parathyroid scintigraphy was reviewed.

RESULTS

Subcapsular parathyroid adenomas tend to conform to the expected shape of the thyroid gland. In this small series, subcapsular parathyroid adenomas followed 1 of 3 patterns on lateral images: (1) focal convex distortion of the posterior wall of the thyroid, (2) polar lentiform configuration, and (3) compression of the posterior thyroid parenchyma.

CONCLUSION

Subcapsular parathyroid adenomas often have a distinct appearance on scintigraphy. Preoperative identification of this type of parathyroid adenoma can direct a subcapsular surgical approach, optimizing the efficiency of the minimally invasive parathyroidectomy.

Enhanced Scintigraphic Protocol Required for Optimal Preoperative Localization Before Targeted Minimally Invasive Parathyroidectomy

At our tertiary care institution, a targeted minimally invasive parathyroidectomy (MIP) is the preferred surgical procedure for primary hyperparathyroidism. Similar to unilateral neck exploration (UNE), preoperative scintigraphic localization of the adenoma in relation to the midline is required. However, in contrast to the abbreviated standard incision for UNE, 2 distinct incision sites, 1 medial and 1 lateral, are available on each side with MIP. The incision site is ultimately chosen based on scintigraphic determination of the adenoma's vascular origin to facilitate ligation and removal. Unfortunately, the scintigraphic location of a parathyroid adenoma does not necessarily reflect the site of its vascular origin. We reviewed our database to identify factors that accurately predict the site of vascular origin of parathyroid adenomas. A retrospective chart review was performed on 125 patients who underwent Tc-99m sestamibi scintigraphy and parathyroidectomy. Scintigraphic localization, surgical findings, and histopathology were recorded. Preoperative image interpretations that were discordant with operative findings were independently reviewed. Scintigraphy identified the presence of an adenoma in 105 of 118 patients (89%) with primary hyperparathyroidism. In 17 of the 105 cases (16%), the scintigraphic interpretation did not accurately reflect the site of superior or inferior vascular origin seen at surgery. In many discordant cases, anterior images were insufficient for determining the vascular origin. The posterior displacement of an adenoma in relation to the thyroid on early lateral images was often critical in determining the superior or inferior vascular origin. Scintigraphic determination of the superior or inferior vascular origin of a parathyroid adenoma directs incision placement for MIP. Imaging protocols should include early lateral images when localizing parathyroid adenomas before minimally invasive parathyroidectomy.

Persistent primary hyperparathyroidism caused by adenomas identified in pharyngeal or adjacent structures

Abnormalities in the normal migration of the parathyroid glands during embryological development of the head and neck may result in considerable variability in the location of parathyroid tissue. Ectopic parathyroid adenomas present diagnostic and technical challenges and are frequently the cause of persistent primary hyperparathyroidism (HPT) after unsuccessful initial parathyroid surgery. We report a series of eight patients with persistent primary HPT who had adenomas in rare and unusual locations associated with various pharyngeal structures. Four were located within the epineurium of the vagus nerve at or above the level of the carotid bifurcation, and four were located within the paranasopharyngeal space or oropharynx. Noninvasive and invasive preoperative imaging studies were crucial in localizing the neoplasms in these patients and permitted the use of a direct surgical approach, resulting in cure in all patients and a low complication rate. The location of parathyroid glands in high pharyngeal and cervical structures is a consequence of anomalous or arrested descent through developing pharyngeal structures and illustrates the remarkable spectrum of ectopic parathyroid adenomas that occur secondary to this phenomenon.

Experienced Scintigraphers Contribute to Success of Minimally Invasive Parathyroidectomy by Skilled Endocrine Surgeons

Minimally invasive parathyroidectomy (MIP) has become the preferred surgical treatment for selected patients diagnosed with primary hyperparathyroidism (PHPT) at our tertiary-care center. Preoperative scintigraphy establishes the position of a parathyroid adenoma, dictates the incision site, and can minimize incision size and consequent tissue dissection. We reviewed our database and sought to identify factors that led to discordant preoperative imaging and operative findings and to assess the effect of experience on these findings. A retrospective review was performed on all patients with biochemically proven PHPT who underwent Tc-99m sestamibi scintigraphy and surgical intervention. Patient demographics, date of surgical intervention, scintigraphic localization, surgical findings, pre- and postoperative biochemical markers, histopathology, coexisting thyroid pathology, and 6-month follow up were recorded. Preoperative images that were discordant with operative findings were independently reviewed. Parathyroid scintigraphy was performed on 125 consecutive patients for PHPT between November 1999 and January 2002. Seventy-six patients had MIPs, 35 had standard cervical explorations, 11 had MIPs that were converted to standard cervical explorations, and three had surgery directed to an ectopic location. At 6-month follow-up 98.4 per cent were cured. Preoperative imaging and surgical findings were ipsilateral and concordant in 105 of 118 (89%) patients with parathyroid adenoma. The anatomic origin of an adenoma was predicted in only 83 of 118 (68%) patients. Most of the inaccurate scintigraphy readings occurred during the first 13 of the 26 months that MIPs were performed at our institution. Only two discordant cases occurred during the last 9 months of this period. Biochemical markers, prior neck operation, and concomitant thyroid pathology had no correlation with imaging sensitivity. Scintigraphic interpretation of smaller adenomas was less reliable; discordant cases were more common in small adenomas. Communication between endocrine surgeons and nuclear medicine physicians about the MIP technique and anatomic orientation of adenomas led to better scintigraphic localization as experience increased. Now that MIP by skilled endocrine surgeons is becoming the favored treatment for PHPT experienced nuclear medicine physicians may be the most important factor to achieve maximum success.

Embryonic parathyroid rests occur commonly and have implications in the management of secondary hyperparathyroidism

BACKGROUND

Recurrence after surgery for secondary hyperparathyroidism is not infrequent. Regrowth of the residual parathyroid tissue after subtotal parathyroidectomy or of the autograft after total parathyroidectomy occurs in many cases. Supernumerary glands are also frequently cited as the offending cause and upon revisiting the neck, the surgeon may be surprised that such an obvious gland was 'missed' at the first operation. Indeed, multiple glands removed in sequential operations have been reported suggesting that they develop over time rather than being present from the start. It is possible that microscopic parathyroid 'rests' of embryological origin proliferate under the ongoing stimulus of renal failure to produce supernumerary glands after apparently adequate initial surgery for hyperparathyroidism. The aim of the present study was to determine whether such rests occur frequently or infrequently.

METHODS

Operative details and pathology results from 60 consecutive parathyroidectomies were reviewed and the occurrence of parathyroid rests noted.

RESULTS

Parathyroid rests were found in 37% of extra parathyroidal tissues submitted for analysis. These rests were found commonly in the thymus. The potential significance of such parathyroid rests undergoing hyperplasia in response to the ongoing stimulus of renal failure and leading to recurrent hyperparathyroidism is discussed.

CONCLUSION

Parathyroid rests are common and potentially serve as a cause of recurrent disease in secondary hyperparathyroidism. Consideration should be given to performing thymectomy as part of the treatment of secondary hyperparathyroidism. A more detailed study is warranted.

Contact endoscopy for intraoperative parathyroid identification

Experienced thyroid surgeons are often able to identify the parathyroid glands, but sometimes it is difficult to differentiate them from other contiguous tissues. Contact endoscopy was introduced in otolaryngology for the characterization of normal and pathological epithelia. Our objective was to analyze contact endoscopy as an auxiliary method for identification of the parathyroid glands during thyroid surgery. Five total thyroidectomies and 5 hemithyroidectomies were performed in September 2001. After surgical exposure, contact endoscopy was performed. A total of 15 peritracheal regions were studied. Superior and inferior parathyroid tissues were identified on the basis of color, size, and probable location. Contact endoscopy was performed before and after use of methylene blue stain. Contact endoscopy was also used in neighboring areas. We compared the visual impression to the contact endoscopy findings. Two structures were visually supposed to be the superior and inferior parathyroid glands in each case. From 30 visually supposed glands, 25 were confirmed by telescope. Of the other 5 structures initially supposed to be parathyroid tissue, 3 were adipose tissue and 2 were thyroid parenchyma. In the 5 cases in which the identification of one of the glands was not confirmed, an additional contact examination enabled us to further identify parathyroid glands in 3 cases in which structures were initially identified as adipose tissue. Contact endoscopy is an efficient auxiliary method for the identification of the parathyroid glands during thyroid surgery that poses little risk of morbidity to the patient.

Surgical anatomy of the thyroid and parathyroid glands

From a surgical viewpoint there are several critical anatomic structures that lie in close proximity to the thyroid gland. These critical structures include the recurrent laryngeal nerves, the superior laryngeal nerves, and the parathyroid glands. Successful thyroid surgery depends on the technical skill of the surgeon to identify and preserve these vital structures.

Ectopic parathyroid adenoma initially suspected to be a thyroid lesion

Considering the variety of aberrant locations in which ectopic parathyroid adenomas may be found, these neoplasms can be difficult to identify and treat surgically. The results of radiographic and cytologic studies may lead to confusion of these neoplasms with lesions of thyroid origin. We present a case of an ectopic parathyroid adenoma for which misleading localization prompted cytologic misdiagnosis and intraoperative suspicion of thyroid carcinoma.

The cricothyroid space: a guide for successful thyroidectomy

OBJECTIVE

The frequent complications of thyroid surgery are mostly related to the anatomy of the region. This stimulated us to look for a starting point that makes exploration of the region easier and consequently reduces complications. We aimed to explore and define the anatomy of the cricothyroid [CT] region from cadaveric dissection and to present the outcome of 73 consecutive thyroidectomies starting from a space in the CT region.

METHODS

Dissection in the thyroid gland region and creating a space in the CT region was performed on five cadavers [10 spaces], followed by 73 consecutive thyroidectomies through a standard approach beginning from the CT space.

RESULTS

In all cadavers, a space was easily created in the CT region. Vessels, nerves and the parathyroid glands were identified. Standard thyroidectomy starting from the CT space was performed on 73 patients. The external laryngeal nerve was seen in 40% of the cases. The recurrent laryngeal nerve was identified and preserved in all patients. Six patients had temporary hypocalcaemia and eight had a temporary voice change. None of the patients had permanent hypoparathyroidism or recurrent laryngeal nerve palsy.

CONCLUSION

The CT space is an avascular space medial to the thyroid lobe and is a good starting point for thyroidectomy that allows easy and safe exploration of the region.

Sonography in primary hyperparathyroidism: review with emphasis on scanning technique

OBJECTIVE

To review the sonographic features and focused sonographic scanning techniques that may assist in the preoperative localization of parathyroid adenomas in patients with primary hyperparathyroidism.

METHODS

The sonographic findings were reviewed in 54 of 58 consecutive patients with pathologically proven parathyroid adenomas. A systematic scanning approach including real-time gray scale, color and power Doppler, and graded compression gray scale imaging was used in all patients.

RESULTS

Fifty-four (93%) of 58 proven adenomas were correctly identified by sonography. Gray scale imaging alone was sufficient for identifying 26 (100%) of 26 large (> or =1-cm) and 3 (11%) of 25 small (<1-cm) parathyroid adenomas. However, for 25 (89%) of 28 small adenomas, a combination of color and power Doppler and graded compression real-time gray scale imaging was required for sonographic localization and identification.

CONCLUSIONS

Knowledge of typical locations and characteristic imaging features, as well as a systematic scanning approach, can result in accurate preoperative sonographic localization of parathyroid adenomas.

Parathyroid adenoma after radioactive iodine therapy for multinodular goiter

The development of hyperparathyroidism after radioactive iodine (RAI) therapy has been reported in 38 cases in the literature. However, the development of a parathyroid adenoma after RAI therapy for a hyperfunctioning multinodular goiter has not been reported. This report describes the pathologic and operative finding on a patient with both hyperthyroidism and hyperparathyroidism, which was diagnosed after previous RAI therapy for a toxic, multinodular goiter.

Multiple Ectopic Parathyroid Glands

Parathyroid surgery to correct primary hyperparathyroidism is successful in 80 to 97 per cent of initial explorations. Failures are often linked to inability to locate ectopic parathyroid glands. Although ectopic parathyroid glands are relatively common (15%) multiple ectopic glands are rarely reported. We describe a case of multiple ectopic parathyroid glands and the intraoperative approach to their localization and review the anatomy and embryology of ectopic parathyroid glands. A 39-year-old woman presented with fatigue, lethargy, and depression. On biochemical evaluation she was noted to be hypercalcemic and hyperparathyroid. Preoperative parathyroid localization failed to identify abnormal parathyroid glands. At exploration three of four parathyroid glands, including an adenoma, were located in ectopic positions by a meticulous and systematic dissection. A careful exploration coupled with a thorough knowledge of parathyroid anatomy and embryology will produce successful surgical correction of primary hyperparathyroidism in greater than 95 per cent of patients even in the few patients with multiple ectopic parathyroid glands.

Minimally invasive parathyroid surgery

More surgeons are performing unilateral exploration for primary hyperparathyroidism (HPT) than ever before. This article reviews the factors that have led to the trend toward less invasive surgery. Discussion includes the history of unilateral exploration for HPT, the advent of magnetic resonance sestamibi imaging, and the development of intraoperative assays for parathyroid hormone. Results of minimally invasive techniques, including radio-guided parathyroidectomy, endoscopic parathyroidectomy, and outpatient parathyroidectomy, also are presented.

Weight characteristics of the parathyroid glands in renal hyperparathyroidism

BACKGROUND

Although the mean weight of normal parathyroid glands is known, reports concerning the weight of hyperplastic glands in renal hyperparathyroidism are rare. The aim was to collect data about the weight of such glands and also to study the intraindividual distribution.

METHODS

Statistical results are presented about the weight of 60 parathyroid glands that were removed in 20 patients with renal hyperparathyroidism (the fourth gland was subtotally removed and therefore not included in the study).

RESULTS

The median weight was 1.005 g, with a range from 0.10 to 7.15 g. All removed glands were enlarged, but the most salient finding was the wide distribution of weights. Also, the intra-individual variation was great. The largest gland of each patient weighed, on average, three to four times more than the smallest gland of the same subject.

CONCLUSION

The weight of the superior glands tended to be somewhat greater in comparison with the inferior glands.

Effect of minimally invasive radioguided parathyroidectomy on efficacy, length of stay, and costs in the management of primary hyperparathyroidism

OBJECTIVE

To compare the first 20 patients who underwent minimally invasive radioguided parathyroidectomies (MIRPs) performed at the authors' institution with 20 similar patients who underwent a more conventional surgical approach for primary hyperparathyroidism.

SUMMARY BACKGROUND DATA

The technique of parathyroidectomy has traditionally involved a bilateral exploration of the neck with the intent of visualizing four parathyroid glands and resecting enlarged parathyroid glands. Parathyroid scanning using radioisotopes has evolved and now can localize adenomas in 80% to 90% of patients. MIRP combines parathyroid scanning with a hand-held intraoperative detector that guides the surgeon to the adenoma.

METHODS

Forty patients with documented primary hyperparathyroidism who underwent surgery by a single surgeon between January 1998 and May 1999 were included in this study. Twenty of these patients underwent MIRP. The technique involved injecting 20 mCi technetium-99m sestamibi 2 hours before surgery and performing a parathyroid scan. If the scan was considered positive for a single adenoma, patients were taken to the operating room and given the choice of either general anesthesia or intravenous sedation with local anesthesia. Using an incision of 4 cm or less, the dissection down to the adenoma was guided by the Navigator miniature hand-held probe. An additional 20 patients who underwent more conventional bilateral or unilateral neck exploration were chosen to match the MIRP patient population. Both groups included four patients undergoing repeat surgery for persistent or recurrent primary hyperparathyroidism and one patient with multiple endocrine neoplasia type 1 syndrome. Patient demographics, preoperative calcium and parathyroid hormone levels, operative time, total time in the operating room, time in the recovery room, complications, hospital charges for the operating room, and total hospital charges were analyzed.

RESULTS

There were no differences in patient demographics, presenting symptoms, or preoperative calcium level between patients undergoing the standard procedure versus MIRP. Operative time, total time in the operating room, operative charges, and total hospital charges were significantly reduced in the MIRP group. All 40 patients were cured of primary hyperparathyroidism. There were no recurrent laryngeal nerve injures in either group. The mean length of stay in the standard group was 1. 35 days; in the MIRP group, 65% of patients were discharged within 5 hours after surgery.

CONCLUSIONS

The MIRP technique resulted in excellent cure rates for primary hyperparathyroidism while simultaneously decreasing operative time and hospital stays. These resulted in significant cost reductions without compromising patient safety. The technique may significantly change the management of primary hyperparathyroidism.

[Supernumerary ectopic hyperfunctioning parathyroid gland: a potential pitfall in surgery for sporadic primary hyperthyroidism]

STUDY AIM

The aim of this retrospective study was to report a series of nine patients with a sporadic primary hyperparathyroidism, operated on for an ectopic supernumerary hyperfunctioning parathyroid gland.

PATIENTS AND METHOD

From 1973 to 1998, among a total of 1,307 patients operated on for a primary hyperparathyroidism, 9 (0.69%) had an ectopic supernumerary hyperfunctioning gland. There were six women and three men (mean age: 63 years) with a sporadic hyperparathyroidism. Initial cervicotomy was performed in our institution in 6 cases. The nine patients underwent 19 operations including one through sternotomy. The ectopic parathyroid gland was localized in the eight patients who had preoperative localization studies.

RESULTS

The supernumerary gland was located in the anterior mediastinum (n = 6), in the carotid sheath (n = 2) and within the vagus nerve (n = 1). In three patients, it was found during the initial cervicotomy. In the 6 other patients, it was found in the course of a reoperation. With a mean follow-up of five years, all the patients were biochemically cured. One patient had a permanent recurrent nerve palsy and a definitive hypoparathyroidism.

CONCLUSIONS

The low incidence of an ectopic supernumerary hyperfunctioning parathyroid gland in sporadic hyperparathyroidism does not justify the routine use of preoperative localization studies and intra-operative quick parathormon assay. During an initial conventional cervicotomy the search for a 5th gland is highly recommended when 4 normal glands have been found in the neck. This research should also be performed in case of multi-glandular disease.

The validity of quick intraoperative parathyroid hormone assay: an evaluation in seventy-two patients based on gross morphologic criteria

BACKGROUND

Parathyroidectomy for primary hyperparathyroidism has conventionally required identification of all parathyroid glands with excision of grossly abnormal glands. Using this approach, cure rates exceed 95%. Directed cervical exploration has been advocated using quick intraoperative parathyroid hormone (QPTH) assay with preoperative localization. Adoption of this approach requires validation of the accuracy of QPTH assay.

METHODS

Patients with primary hyperparathyroidism undergoing bilateral neck exploration during a 31-month period were reviewed. Uniglandular (UGD) or multiglandular (MGD) disease was determined by gross morphologic criteria. QPTH assays were performed before skin incision and at 5, 10, and 20 minutes after excision of each abnormal gland. A 10-minute QPTH decrease of 50% from baseline levels indicated curative excision. These data were not used to guide extent of exploration or tissue resection.

RESULTS

Of 72 patients, 55 (76%) had UGD and 17 (24%) had MGD. QPTH assay accurately predicted the disease state in 89%. Four (7%) UGD patients did not have an appropriate QPTH decline at 10 minutes. Four (24%) MGD patients had an inappropriate QPTH decline at 10 minutes.

CONCLUSIONS

Using QPTH guided exploration, 6% (4 of 72) of patients would undergo unnecessary extended exploration and 6% (4 of 72) (95% CI, 1% to 13%) may require reoperation for unidentified MGD. These results validate the accuracy of QPTH assay.

Parathyroid adenomas: is bilateral neck exploration necessary?

PURPOSE

The traditional surgical treatment for primary hyperparathyroidism is bilateral neck exploration with identification of all parathyroid glands. Multiple investigators who recommend initial unilateral neck exploration based on more advanced localization studies have recently challenged this approach. We reviewed our experience with primary hyperparathyroidism to determine if localization study-aided unilateral neck exploration is sufficient for a cure.

MATERIALS AND METHODS

Retrospective chart review of patients with primary hyperparathyroidism.

RESULTS

Sixty-eight patients underwent surgery for primary hyperparathyroidism. Forty-four patients were treated with localization study-aided unilateral neck exploration, and 24 patients were treated with bilateral neck exploration without preoperative localization studies. The most successful preoperative localization study was the technetium 99m sestamibi (T99mS) scan which correctly identified the location of adenomas in all cases in which it was used (n = 15). All patients were treated with unilateral neck exploration and were cured. This success was matched only by surgical exploration (n = 24).

CONCLUSION

Unilateral neck exploration based on the results of a T99mS scan can be used as an initial approach for primary hyperparathyroidism if the scan identifies a solitary lesion. The second gland on the same side of the lesion should be biopsied, and if it is normal, the opposite side of the neck may be left undisturbed. If the second gland is not normal, or if the T99mS scan shows multiple lesions, bilateral neck exploration should be performed.

Unsuspected intrathyroidal parathyroid adenoma: mimic of lymphocytic thyroiditis in fine-needle aspiration specimens-a case report

Fine-needle aspirations (FNAs) of parathyroid adenomas (PA) are infrequently encountered, but the scant literature on this topic emphasizes the difficulties in distinguishing them from thyroid neoplasms. We report on a case of an unsuspected intrathyroidal PA whose two FNA specimens mimicked almost perfectly the features of lymphocytic thyroiditis (LT). The smears from two FNAs of a "thyroid nodule" in a 22-yr-old woman were received with a clinical diagnosis of "LT." The cytological features of both specimens were similar and consisted of groups of epithelial cells in a background of numerous "naked" nuclei, interpreted as Hurthle cells and lymphocytes respectively, and leading to a cytological diagnosis of LT. Subsequent surgical excision of the "nodule" revealed a large intrathyroidal PA. The oxyphil cells and chief cells (the latter devoid of cytoplasm) present in the PA resembled Hurthle cells and lymphocytes respectively, in the FNA specimens. In conclusion, PA can give a cytological picture almost identical to that of LT in FNA material. Important clues to the diagnosis of PA in FNA specimens include the presence of prominent capillaries and the knowledge of a clinical history of hyperparathyroidism. Diagn. Cytopathol. 1999;21:276-279.

Unintentional parathyroidectomy during thyroidectomy

OBJECTIVES

In the United States thyroidectomy is a frequently performed surgery by both general and head and neck surgeons. Even the most experienced thyroid surgeon, however, has probably received a pathology report stating that an incidental parathyroid gland or parathyroid tissue was found in the submitted thyroidectomy specimen. The aim of this report is to explore some of the pathologic and clinical characteristics of unintentional parathyroidectomy during thyroidectomy.

STUDY DESIGN

A retrospective review was performed of thyroidectomies performed at the University of California, Los Angeles, Center for the Health Sciences between 1989 and June 1998 which had pathology reports showing parathyroid tissue contained within the thyroidectomy specimen. This excluded any tissue submitted separately to be evaluated for parathyroid tissue and parathyroid tissue removed unintentionally during a thyroidectomy for a different procedure such as a laryngectomy or surgery for parathyroid disease.

METHODS

The pathology slides were reviewed to determine the incidence of unintentional parathyroid tissue removal, the size of the parathyroid tissue found within the thyroid specimen, the location of the parathyroid tissue (extracapsular, intracapsular, intrathyroidal), and whether this unintentional parathyroidectomy during thyroidectomy caused clinical consequences.

RESULTS

Four hundred fourteen applicable thyroidectomies were performed during this time with 45 (11%) discovered cases of unintentional parathyroidectomy during thyroidectomy. Twenty-five (56%) cases were discovered during thyroidectomy for benign disease, and 20 (44%) during thyroidectomy for malignant thyroid disease. All the parathyroid tissue was normal and was found in extracapsular (58%), intracapsular (20%), or intrathyroidal (22%) locations. Of these 45 cases, recurrent laryngeal nerve paralysis was found only in two patients who had the nerve resected intentionally during the thyroidectomy, and none of the patients developed permanent hypocalcemia.

CONCLUSIONS

Incidental parathyroid gland tissue was reported in 11% of the thyroidectomies performed in our series, without the clinical consequence of hypocalcemia. The majority (78%) of this parathyroid tissue was found in the extracapsular and intracapsular locations; therefore it is possible that these parathyroid glands may be identified and preserved with more meticulous inspection of the thyroid capsule during and after thyroidectomy to decrease the incidence of unintentional parathyroidectomy during thyroidectomy in the future.