Elsevier

The Surgeon

Volume 17, Issue 4, August 2019, Pages 201-206
The Surgeon

Full Length Article
Renal failure parathyroidectomy – Is pre-operative imaging worthwhile?

https://doi.org/10.1016/j.surge.2018.07.002Get rights and content

Abstract

Background

Tertiary hyperparathyroidism is a significant issue in renal failure patients and some require surgery to control their serum calcium. A number of imaging techniques are used to localise the position of the parathyroid glands prior to surgery.

Currently, a combination of ultrasound and isotope preoperative localisation imaging is accepted as useful in parathyroid surgery for primary disease. However, the use of pre-operative imaging in parathyroid surgery in renal failure patients is uncertain.

The role of pre-operative imaging of the parathyroid glands in patients with renal failure hyperparathyroidism was assessed with imaging outcomes compared to operative and pathological findings in two cohorts of patients undergoing parathyroid surgery – primary and tertiary.

Methods

All data were collected prospectively over a 10-year period (2003–2013) from the practice of a single surgeon. Patients were grouped into either primary hyperparathyroidism (49 patients) or tertiary hyperparathyroidism (41 patients).

The majority, 63 of 90 (70%) patients, underwent both ultrasound (US) and isotope (MIBI) pre-operative imaging. Pre-operative imaging was correlated with operative and pathological findings.

Findings

Comparison of the results of the two groups using ordinal regression analysis confirmed these imaging techniques are significantly more accurate in primary than tertiary parathyroid surgery (p = 0.022).

Conclusions

While accepted practice of pre-operative combined USS and MIBI imaging is essential in unilateral imaged-focused neck exploration for primary disease, these imaging techniques have a more limited use pre-operatively in renal failure parathyroidectomy.

Introduction

Hyperparathyroidism (HPT) describes a condition characterised by excessive secretion of parathyroid hormone (PTH), a polypeptide hormone produced by the parathyroid glands. PTH induces osteoclastic activity, reducing bone density, and increasing serum calcium. This increase in serum calcium can result in a wide range of clinical presentations, or alternatively patients may be asymptomatic and present incidentally.1

Primary hyperparathyroidism (PHPT) can be due to hyperplasia, but is more commonly (80% of patients) due to an adenoma of one or more of the parathyroid glands, with a single adenoma being the most common presentation. If symptomatic, surgical excision is considered as standard provided the patient is fit for surgery.2

In secondary hyperparathyroidism (SHPT), reduced activation of Vitamin D and phosphate retention resulting from declining renal function, trigger a decrease in calcium absorption and increased PTH secretion.3 In renal failure patients, transplantation has been demonstrated to biochemically reverse this condition.3

It is after renal replacement therapy, either transplantation or dialysis, that tertiary hyperparathyroidism (THPT) presents. Parathyroid tissue which was previously driven by hypocalcaemia and hyperphosphataemia, fail to return to their normal state and continue their increased level of PTH secretion, resulting in hypercalcaemia.3 This causes significant morbidity in renal transplant patients, with 17–50% of patients at 1 year displaying this condition.1 It increases the risk of graft dysfunction and loss, bone disease, and cardiovascular morbidity.2 Traditionally, like PHPT, THPT has been treated surgically.1 Medical management of THPT using calcimimetic agents has gained recognition. However, a 2017 systematic review concluded that surgical management of tertiary HPT had higher cure rates than medical therapy. Surgery is still the preferred therapy for the majority of patients.1

In primary disease, optimal surgical management is local and targeted, therefore accurate imaging for localisation is essential to reduce the need for bilateral neck exploration.4

Although the majority of parathyroid glands are distributed among the four usual anatomical positions (left inferior, left superior, right superior, and right inferior), intra-operative localisation can be challenging.5 It is reported that 6.5%–14% of the population have supernumerary glands, usually located in the thymus, with 16%–43% having one or more ectopic glands.5, 6, 7, 8 The variability of individual gland location is due to their complex descent from the third and fourth pharyngeal pouches during foetal development.9

Pre-operative imaging is used to increase the accuracy of intra-operative location of parathyroid glands.10 Ultrasound (US), 99mTc-sestamibi isotope imaging (MIBI) and, less commonly, magnetic resonance imaging (MRI), and single-proton emission computed tomography (SPECT) imaging are used.11, 12 US and MIBI are most popular, with US being readily available and MIBI regarded as having the highest sensitivity (57–82%) of the two imaging modalities in PHPT.10, 11 Most accept that for PHPT, a combination of USS and MIBI imaging is best, yet there is still debate of which localisation method is superior and in which combination for patients with THPT. The majority of studies examining the efficacy of pre-operative imaging in HPT report on patients with PHPT or SHPT.11, 12, 13

Studies exploring the efficacy of pre-operative imaging in THPT are fewer in number with small sample sizes. Published reports of the overall efficacy of MIBI imaging in THPT disease have demonstrated sensitivities of between 37% and 76%.2, 13 These studies have been small descriptive series which do not offer a comparative statistical analysis of their results.

The aim of this study is to add to the evidence determining the efficacy of pre-operative imaging in patients with tertiary hyperparathyroidism. A comparison with a concurrent series of primary HPT was performed.

Section snippets

Methods and materials

A non-randomised analysis of 90 consecutive patients with a pre-operative diagnosis of either primary HPT or tertiary HPT was conducted. The data were collected prospectively. These were from the practice of a single surgeon, in one centre, between July 2003 and May 2013. This centre is host to the regional renal transplant unit.

Demographic, clinical, and pathological data collected included patient age (years) at time of surgery, PHPT or THPT status, pre- and post-operative PTH and serum

Results

The records of 90 patients who underwent parathyroidectomy over a period of 10 years (July 2003–May 2013) were analysed. 49 patients were diagnosed with PHPT and 41 patients with THPT. There were 60 males and 30 females.

Mean age at time of surgery was 52.8 years and median follow-up post-operatively was 69 months.

There were no peri-operative, 30-day, or 90-day mortality; but 9 deaths occurred within the follow-up period unrelated to the surgery, with these patients all having THPT. The

Discussion

When ultrasound and MIBI imaging results were analysed using ordinal regression analysis, it was demonstrated these imaging techniques in combination are significantly more accurate in primary than tertiary parathyroid surgery (p = 0.022). Additionally, it was demonstrated that pre-operative serum corrected calcium is positively correlated with imaging success in tertiary HPT (p = 0.003), this correlation has not to the authors’ knowledge been reported before in the literature.

While the

Conclusion

Accepted practice of pre-operative combined USS and MIBI imaging is essential in unilateral, imaged-focused neck exploration for PHTP disease. However, we believe that these imaging techniques have more limited use pre-operatively in renal failure patients presenting with THTP, although they may still be useful in the patient undergoing re-exploration, and in those who may have ectopic glands.

Declaration of interest

None.

Source of financial support

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Acknowledgements

We would like to thank Dr Michael Stevenson (Queen's University, Belfast) for the assistance with statistical analysis.

References (20)

There are more references available in the full text version of this article.

Cited by (6)

  • Sestamibi scan in renal parathyroidectomy: a worthwhile preoperative exam?

    2022, Brazilian Journal of Otorhinolaryngology
    Citation Excerpt :

    Our experience about this subject has also been published.11,12 The analysis of these studies indicates that localization exams are not essential for the success of PTX in this group of patients9 and could even be considered secondary.12 Nevertheless, physicians across the country seem too apprehensive in performing surgery without it.

This manuscript has been published previously as an abstract – In the proceedings of the ASGBI International Surgical Congress.

View full text