To the Editor
We have read with great interest the article by Sheng et al. on the impact of parathyroid gland (PG) classification on hypoparathyroidism following total thyroidectomy with central neck dissection for differentiated thyroid cancer [1]. The authors’ effort to establish a simplified PG classification system to predict postoperative hypoparathyroidism is both clinically relevant and methodologically ambitious. However, upon detailed review, we have identified several methodological and interpretive issues that merit further discussion.
The most pressing concern relates to the subjective nature of the PG classification system. Although the authors categorized PGs into four types based on anatomical and vascular characteristics, the classification relies heavily on intraoperative visual assessment without objective biomarkers or imaging confirmation. This introduces significant inter-observer variability, which may affect the reproducibility of the results. Prior studies have emphasized the importance of adjunctive technologies such as indocyanine green angiography or near-infrared autofluorescence for objective PG identification [2,3]. The absence of such technologies in this study may limit the generalizability of the findings.
Additionally, the study reports that all cases of hypoparathyroidism resolved within six months, with no permanent hypoparathyroidism. While this is encouraging, it contrasts with broader literature where permanent hypoparathyroidism occurs in 1–5% of cases after total thyroidectomy with central dissection [4]. The relatively small sample size (n = 135) and single-center design may not fully capture the risk of permanent dysfunction, particularly in high-risk anatomical variants.
The regression analysis indicated that each additional tightly connected PG increased the risk of hypoparathyroidism by 1.38 times (p = 0.019), with a cutoff of two glands. However, the ROC curve analysis showed only modest predictive accuracy (AUC = 0.604), suggesting that PG type alone may be insufficient for robust clinical prediction. Multivariate models incorporating patient demographics, surgical experience, and gland vascularity may improve predictive performance.
Finally, the study advocates for in situ preservation of all PGs regardless of type, contrary to some guidelines that recommend autotransplantation for devascularized glands [5]. While the authors report good functional recovery, the lack of comparative data on autotransplantation leaves open the question of whether selective transplantation could further reduce temporary hypoparathyroidism.
In conclusion, while the proposed PG classification system offers a pragmatic intraoperative tool, its clinical utility requires validation through larger, multi-center studies incorporating objective imaging and standardized surgical protocols. We commend the authors for their contribution and encourage further research to refine predictive models for postoperative hypoparathyroidism.
Acknowledgments
Yingchun Zhou, Visualization, Writing–original draft. Dongdong Zhang: Conceptualization, Writing–original draft, Writing–review and editing. Ming Cai: Conceptualization, Supervision, Writing–original draft, Writing–review and editing.
Funding Statement
No funding.
Disclosure statement
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Data availability statement
Data sharing is not applicable to this article as no new data were created or analyzed in this study.
References
- 1.Sheng Q, Li W, Zhang P, et al. Impact of parathyroid gland classification on hypoparathyroidism following total thyroidectomy with central neck dissection for differentiated thyroid cancer. Ann Med. 2025;57(1):2476223. doi: 10.1080/07853890.2025.2476223. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Benmiloud F, Godiris-Petit G, Gras R, et al. Association of autofluorescence-based detection of the parathyroid glands during total thyroidectomy with postoperative hypocalcemia risk: results of the PARAFLUO multicenter randomized clinical trial. JAMA Surg. 2020;155(2):106–112. doi: 10.1001/jamasurg.2019.4613. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Wang Z, Zhang F, Zhu C, et al. Preoperative total parathyroid volume is an independent marker to predict recurrence for secondary hyperparathyroidism. Ann Med. 2024;56(1):2428435. doi: 10.1080/07853890.2024.2428435. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Puzziello A, Rosato L, Innaro N, et al. Hypocalcemia following thyroid surgery: incidence and risk factors. A longitudinal multicenter study comprising 2,631 patients. Endocrine. 2014;47(2):537–542. doi: 10.1007/s12020-014-0209-y. [DOI] [PubMed] [Google Scholar]
- 5.Lorente-Poch L, Sancho JJ, Ruiz S, et al. Importance of in situ preservation of parathyroid glands during total thyroidectomy. Br J Surg. 2015;102(4):359–367. doi: 10.1002/bjs.9676. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
Data sharing is not applicable to this article as no new data were created or analyzed in this study.