Role of Imaging in the Localization of Parathyroid Adenoma Authors S A Kabir 1, Z Khanzada 2, S I Akhtar 3, S I Kabir 4, N Wariach 1, 1. Department of Surgery, Lincoln County Hospital, Lincoln LN2 5QY, United Kingdom. 2. Department of Colorectal Surgery, University Hospital of Wales, Cardiff, UK. 3. Department of Surgery, Kings Mill Hospital, Sutton-in-Ashfield, United Kingdom. 4. Department of Surgery, Wycombe General Hospital, High Wycombe. HP11 2TT, United Kingdom. Corresponding Author S A Kabir adnankabir58@hotmail.com Lead Consultant Mr. Irfan Akhtar, Department of Surgery, Kings Mill Hospital, Sutton-in-Ashfield, United Kingdom. The Online Journal of Clinical Audits, 2014. Vol 6(2) Published June 2014 To subscribe to The Online Journal of Clinical Audits go to: http://www.clinicalaudits.com/index.php/ojca/user/register Article submission and authors instructions: http://www.clinicalaudits.com/index.php/ojca/about/submissions
Aims - Recently minimally invasive parathyroidectomy has been developed. For this reason, preoperative localization is playing an important role to detect the precise location of the affected gland and to increase success rate. It has been mentioned in the literature that if preoperative localization of parathyroid gland is considered necessary the investigations of choice are 99Tc Sestamibi scanning, and High-resolution ultrasonography. Therefore, the aim of this study is to evaluate the choice of investigation in localizing parathyroid adenoma. Methods - Retrospective Study, Imaging, Frozen section & qpth reports of patients [n= 37] with diagnosis of primary hyperparathyroidism who had undergone parathyroidectomy were reviewed, at King Mills Hospital between May 2010 and Dec.2011. Results - 37 patients underwent combined USS & Sestamibi scan, Parathyroid adenoma was localized via USS 25/37 (67.56%), as against 34/37 (91.89%) by Sestamibi-scan and by combined i.e. USS & Sestamibi-Scan 36/37 (97.29%). Histology reported adenomas 32/37 (86.48%), hyperplasia 2/37 (5.40%), carcinoma 1/37 (2.7%), normal histology 2/37 (5.40%) (USS & mibi scan Negative). In addition to the above, intra operative qpth showed high levels in 35/37 cases out of which 2 continue to have high levels even after repeating the qpth levels; both patients had normal histology post operatively; out of which 1 was re-operated (adenoma) the other refused surgery. Conclusions - Combined USS and Sestamibi-scan was found to localize parathyroid adenomas with high degrees of accuracy in our hospital (97%). There is also an advantage of doing quick PTH levels compared to frozen section. Introduction Hyperparathyroidism is a disease characterized by high serum calcium levels along with elevated parathyroid hormone (PTH) levels, which occurs with a prevalence of 3/1000 in the general population. 1 In 1925, Mandl 2 performed the first Parathyroidectomy in a patient who suffered with severe bone disease. Since then, the treatment of hyperparathyroidism has undergone dramatic changes over the last 20 years, mainly due to the development of new technological advances in imaging such as Ultrasound scans (USS), Sestamibi scans (Mibi-scan), Computer-Tomographic scans (C.T) and Magnetic Resonance scans (MRI-scan), to help us accurately localize abnormal glands preoperatively. It is important to note that in the hands of an experienced surgeon bilateral neck exploration for Primary Hyper-Parathyroid (PHP) cures 95% of the cases, 3 i.e. without the use of imaging to locate the parathyroid gland, and it is due to this very reason that the National Institutes of Health (NIH) released guidelines in 1990 for the treatment of PHP; Included recommendation that pre-operative localization was not indicated 4. However, with the advent of rapid intra-operative qpth assays and highly sensitive (90.7%) and specific (98.8%) Mibi-scan 2 has rekindled interest in pre-operative localization of parathyroid gland for direct unilateral exploration also known as the Focused Approach.
In addition to the above, it is also due to these aforementioned new technological advances that minimally invasive parathyroidectomy has been developed and preoperative localization is playing an important part in detecting the precise location of the affected parathyroid gland to increase its success rate. Authors have suggested that if preoperative localization is considered necessary the investigations of choice are 99Tc Sestamibi scanning, and High-Resolution ultrasonography, and this will be required if a focused approach & limited neck dissection is to be performed. 2 Aims The main aim of this study is to evaluate the choice of investigation in localizing parathyroid adenoma prior to minimal invasive parathyroid surgery. Audit Standards If pre-operative localization of the parathyroid gland is considered necessary i.e. a focused approach and limited neck dissection is to be performed; the investigations of choice are 99Tc Sestamibi scanning, and High-Resolution ultrasonography. 2 Methods We did a retrospective study with Imaging, frozen section & qpth reports of thirty eight (38) patients with a diagnosis of primary hyperparathyroidism, and who underwent minimal invasive parathyroidectomy, were reviewed, at King Mills Hospital between May 2010 and Dec.2011. One of the patients had a C.T scan after negative bilateral exploration for parathyroidectomy, and was excluded from the study as did not have any previous imaging. Results A total of 37 patients (n=37) underwent combined USS & Sestamibi scan, except one (1) CT after negative bilateral exploration. Parathyroid adenoma was localized via USS 25/37 (67.56%), as against 34/37 (91.89%) by Sestamibi-scan and by combined i.e. USS & Sestamibi-Scan 36/37 (97.29%) (Figure1). Only one (1) patient underwent CTscan, after bilateral negative parathyroid exploration, 1/1 (100%).
Figure 1 Figure 2 Confirming our results with the histology reports, adenomas 34/37, 91.89% (1 bilateral), hyperplasia 2/37 (5.40%), carcinoma 1/37(2.7%), normal histology 1/37 (2.7%) (Figure 2), the patient had bilateral neck exploration after negative USS & mibi scan), intra operative qpth showed high levels in 35/37 cases out of which 1/35 continue to have high levels and had normal post-op histology, the patient was re-operated after C.T confirmation of adenoma. Discussion/Conclusions There is no doubt that with the advent of rapid intra-operative qpth assays and highly sensitive (90.7%) and specific (98.8%) Mibi-scan 1 has rekindled interest in preoperative localization of parathyroid gland for minimal invasive procedures.
However, our study has shown that combined approach i.e. USS and mibi-scan was found to localize parathyroid adenomas with high degrees of accuracy in our hospital (97.29%). Only One (1) patient, who had gone through both the imaging, unfortunately could not be picked up initially but, was later localized with C.T. Also, there is also an advantage of doing quick PTH levels compared to frozen section in helping us with the diagnosis as results of frozen section takes time to complete. If initially both USS and Mibi-scan does not locate the parathyroid gland then we should aim for a C.T, rather than go straight for surgery. Recommendations We would recommend the use of both USS and Mibi-scan along with the use of C.T scan if parathyroid gland could not be localized by initial means. References: 1 Adami S, Marcocci C, Gatti D. Epidemiology of primary hyperparathyroidism in Europe. J Bone Miner Res 2002; 17(Suppl 2): N18-23 2 William B Inabnet, James A. Lee. Parathyroid disease, syndromes and pathophysiology. Companion to specialist surgical practice, Endocrine surgery. 4th Edn. pp.1-17. 2009. 3 Van Heerden J. Lessons learned. Surgery 1997; 122(6): 978-988. 4 Consensus Development Conference Panel. Diagnosis and management of a symptomativ primary hyperparathyroidism: Consensus Development Conference statement. Ann Intern Med 1991; 114:593-7.