Partial median sternotomy: an attractive approach to mediastinal parathyroid disease

A case of mediastinal hyperparathyromatosis

Recurrent hyperparathyroidism (HPT) after initial parathyroid surgery occurs rarely in an ectopic location. The rare phenomenon of parathyromatosis may be the cause of this. We present the case of a 59-year-old woman with recurrent HPT, which presented as a new ectopic mediastinal parathyroid gland 13 years after initial 3.5 gland parathyroidectomy. A 1.5 × 1.3 cm lesion was discovered as an incidental finding in the pretracheal region, closely abutting the aortic arch. An aspirate revealed oncocytic cells, which were positive for parathyroid hormone, confirming a mediastinal parathyroid nodule. Sestamibi scan confirmed an avid nodule in the mediastinum. This patient had multiple co-morbidities but was asymptomatic of HPT. It was therefore decided at multi-disciplinary team discussion that she should undergo surveillance. To our knowledge, no such presentations have been reported in the literature. Thus, our case report is a unique addition of an atypical presentation of HPT.

Surgery in primary hyperparathyroidism: extensive personal experience

Parathyroidectomy is the optimal treatment for primary hyperparathyroidism (PHPT) and provides a cure in the vast majority of cases. Over the last 2 decades, improvements in preoperative localization and the development of intraoperative parathyroid hormone monitoring have opened the door for new surgical approaches to parathyroidectomy. Minimally invasive parathyroidectomy is performed under regional or local anesthesia. It requires less surgical dissection resulting in decreased trauma to tissues and is more effective and less costly than traditional bilateral cervical exploration. This article reviews our approach reflecting advances in preoperative localization, anesthetic techniques, and intraoperative management of patients undergoing parathyroidectomy for the treatment of PHPT.

Influence of surgical volume on operative failures for hyperparathyroidism

Hyperparathyroidism is a disease that is often seen in the United States. Patients may present with a wide variety of symptoms affecting multiple organs, but frequently, they are found to be hyperparathyroid on a routine blood examination. Although these patients may be asymptomatic, new consensus guidelines exist for when they should undergo surgery, and several studies have shown multiple benefits from operative intervention. Surgical cure rates can be greater than 95%, but if the initial surgery is unsuccessful, the cure rate becomes 80%. In the hands of experienced surgeons, both initial cure rates and those for reoperations are much higher, illustrating that the surgical volume does affect failure in parathyroid surgery.

Intraoperative determination of PTH concentrations in fine needle tissue aspirates to identify parathyroid tissue during parathyroidectomy

BACKGROUND

Exact tissue identification during parathyroidectomy is essential to successfully cure hyperparathyroidism. PTH level determination from tissue aspirates has been advocated as a "biochemical frozen section" for parathyroid tissue identification. We investigated the sensitivity and specificity of this method in a large cohort of consecutive patients who underwent parathyroidectomy in a tertiary referral center.

METHODS

PTH levels of 359 tissue aspirates were measured intraoperatively in 223 consecutive patients from March 2006 to December 2008. Suspected parathyroid and control tissues were aspirated with a standardized technique immediately after their excision. Samples were processed for quick-PTH assay with peripheral blood samples before and after excision. PTH levels from tissue aspirates were correlated with pathological diagnosis. The Mann-Whitney test was used to determine statistical significance (P < 0.05).

RESULTS

A total of 255 parathyroid (196 adenoma, 30 hyperplasia, 4 carcinoma, 25 normal parathyroid) and 104 nonparathyroid tissue (88 thyroid, 16 lymph node, thymus, or fat) aspirates were compared. A highly significant difference was found between PTH levels of parathyroid (8,120 +/- 2,711 pg/ml; interquartile range (IQR): 4,949-9,075) and nonparathyroid (0.8 +/- 9.29 pg/ml; IQR: 0.4-1.4) tissue aspirates (P < 0.005). This test is 100% sensitive and 100% specific to identify parathyroid tissue for values >84 pg/ml. Furthermore, PTH levels of pathological parathyroid aspirates (8,169 +/- 2,597; IQR: 5,634-9,109) were higher than that of normal parathyroid aspirates (4,130 +/- 2,952; IQR: 2,569-8,284; P = 0.0011).

CONCLUSIONS

PTH level determination from tissue aspirates is a highly reliable, quick, and simple method to differentiate parathyroid and nonparathyroid tissues during parathyroidectomy. This method can obviate frozen sections in patients undergoing surgery for hyperparathyroidism.

Minimally invasive parathyroidectomy

Minimally invasive parathyroidectomy (MIP) is an operative approach for the treatment of primary hyperparathyroidism (pHPT). Currently, routine use of improved preoperative localization studies, cervical block anesthesia in the conscious patient, and intraoperative parathyroid hormone analyses aid in guiding surgical therapy. MIP requires less surgical dissection causing decreased trauma to tissues, can be performed safely in the ambulatory setting, and is at least as effective as standard cervical exploration. This paper reviews advances in preoperative localization, anesthetic techniques, and intraoperative management of patients undergoing MIP for the treatment of pHPT.

Remedial operation for primary hyperparathyroidism

BACKGROUND

Remedial surgery for patients with persistent or recurrent primary hyperparathyroidism (1 degrees HPT) remains a significant challenge. Cervical reexploration is technically difficult; reoperative neck anatomy is distorted by fibrosis and, as a result, remedial 1 degrees HPT patients carry an increased risk of injury to the recurrent (RLN) and superior laryngeal nerve(s) as well as to normal residual parathyroid tissue. Causative hyperfunctioning parathyroid tissue is also more frequently ectopic in the remedial setting and can thus be difficult to localize.

METHODS

This report assimilates the current data underlying preoperative, intraoperative and postoperative remedial 1 degrees HPT management and presents an evidence-based algorithm for the management of remedial parathyroid disease. Recommendations are graded according to the quality of supporting data using the system initially developed by Sackett (Chest 95:2S-4S, 1989) and subsequently modified by Heinrich et al. (Ann Surg 243:154-168, 2006).

RESULTS

Recent advances in preoperative localization and intraoperative adjuncts have lead to substantial improvements in outcomes after remedial surgery. Preoperative localization techniques, including sestamibi scintigraphy (MIBI), high resolution ultrasound (US), US-guided fine needle aspiration (FNA) and selective venous sampling (SVS), coupled with intraoperative adjuncts such as the rapid parathyroid hormone (PTH) assay have lead to reoperative cure rates as high as 96 percent. Nonetheless, management of remedial 1 degrees HPT varies significantly between surgeons and no formal recommendations standardizing the care of these patients have been published.

CONCLUSIONS

Despite the significant challenges associated with remedial surgery for 1 degrees HPT, excellent outcomes can be reproducibly achieved when proper pre-, intra-, and postoperative management is employed.

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.

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.

Focused approach to parathyroidectomy

Minimally invasive parathyroidectomy is performed after preoperative parathyroid localization-usually with high-quality sestamibi scans and/or ultrasonography-often under cervical block anesthesia during which a limited exploration is performed. The rapid intraoperative parathyroid hormone assay is then employed to confirm an adequate resection and cure of primary hyperparathyroidism. This article discusses imaging, anesthesia, results, and the surgical management of patients undergoing minimally invasive parathyroidectomy.

Remedial parathyroid surgery: changing trends in 130 consecutive cases

OBJECTIVE

To review the outcomes in 130 consecutive remedial explorations for primary hyperparathyroidism.

SUMMARY BACKGROUND DATA

Remedial surgery for primary hyperparathyroidism is challenging and requires meticulous preoperative evaluation and imaging to expedite a focused surgical exploration that has traditionally been performed under general anesthesia. This prospective series of 130 consecutive remedial operations for primary hyperparathyroidism selectively used minimally invasive techniques and tested the hypothesis that these techniques could improve outcomes.

METHODS

Between 1990 and 2005, 1,090 patients were evaluated and explored for primary hyperparathyroidism. Of these, 130 remedial explorations were performed in 128 patients who underwent either conventional exploration under general anesthesia (n = 107) or minimally invasive parathyroidectomy (n = 23) employing cervical block anesthesia, directed exploration, and curative confirmation with the rapid intraoperative parathyroid hormone assay.

RESULTS

The sensitivity of preoperative imaging were: Sestamibi (79%), ultrasound (74%), MRI (47%), CT (50%), venous localization (93%), and ultrasound guided parathyroid fine needle aspiration (78%). The cure rate in the conventional remedial group (n = 107) was 94% and was associated with a mean length of stay of 1.6 +/- 0.2 days. Remedial exploration employing minimally invasive techniques (n = 23) resulted in a cure rate of 96% and a mean length of stay of 0.4 +/- 0.1 days. Complications were rare in both remedial groups. These results were almost identical to those achieved in 960 unexplored patients.

CONCLUSIONS

Remedial parathyroid surgery can be accomplished with acceptable cure and complication rates. Minimally invasive techniques can achieve outcomes that are similar to those obtained in unexplored patients.