Dear Editors,
The authors would like to thank Prof K Padmanabhan and Dr D Pulimoottil for their interest and comments in relation to our articleReference Hone, Tikka, Kaleva, Hoey, Alexander and Balfour 1 and the Journal of Laryngology & Otology for the chance to respond. Our study aimed to address factors that may be associated with parathyroid removal, rather than directly investigating the effect of incidental parathyroidectomy on post-operative hypocalcaemia.
The authors appreciate that preservation of the parathyroid glands is likely to influence calcium levels; however, the cause of post-operative hypocalcaemia is multifactorial. Furthermore, the theory that parathyroid injury or devascularisation leads to hypocalcaemia cannot be reliably assessed based on review of histological specimens. The study by Song et al. showed a statistically significant increase in transient hypocalcaemia following incidental parathyroidectomy on multivariate analysis,Reference Song, Jung, Ji, Min, Ahn and Tae 2 and is supported by other literature.Reference Khairy and Al-Saif 3 , Reference Sippel, Ozgul, Hartig, Mack and Chen 4 However, other studies have not found an association between inadvertent parathyroidectomy and hypocalcaemia.Reference Yazici, Bozkurt, Citgez, Kaya, Mihmanli and Uludag 5 – Reference Gourgiotis, Moustafellos, Dimopoulos, Papaxoinis, Baratsis and Hadjiyannakis 8 A systematic review and meta-analysis may help to develop understanding of the relationship between incidental parathyroidectomy and hypocalcaemia.
All surgeons in our study were in the first half of their careers and routinely supervised training surgeons. Surgical experience is a well-recognised factor affecting surgical outcomes and this should be considered when assessing any post-operative complication.
Intra-operative and early post-operative serum parathyroid hormone (PTH) levels are an established but expensive (although potentially cost-effective) method of attempting to predict post-operative hypocalcaemia following total or completion thyroidectomy. Low levels may encourage early calcium supplementation to prevent hypocalcaemia.Reference Payne, Tewfik, Hier, Tamilia, Mac Namara and Young 9 – Reference Payne, Hier, Cote, Tamilia, MacNamara and Black 13 In the UK, rapid PTH measurement is not routinely available in many centres, and therefore is not recommended by the British Thyroid Association or British Association of Endocrine and Thyroid Surgeons.
The study by Tripathi et al. shows an association between low vitamin D levels and post-operative hypocalcaemia.Reference Tripathi, Karwasra and Parshad 14 Indeed, there are high levels of vitamin D deficiency in the UK, and a recent UK government commission report suggested all women in the UK should take a daily 10 µg supplementation. Hence, there may be a potential role for vitamin D supplementation when preparing patients for thyroid surgery.
