Surgery, Gastroenterology and Oncology

Background: Thyroidectomy, the surgical removal of all or part of the thyroid gland, is commonly performed for both malignant and benign conditions. While generally safe, it carries risks such as hypocalcemia, often caused by parathyroid gland injury. Hypocalcemia, defined by low serum or ionized calcium levels, may present early or persist long-term. Purpose: To evaluate the incidence and characteristics of early and late hypocalcemia in patients undergoing thyroidectomy.

Methods: A prospective observational cross-sectional study was conducted at Al-Nasiriyah Teaching Hospital over one year (April 2024–April 2025) to assess the incidence and characteristics of early and late hypocalcemia following thyroidectomy. Eighty-five adult patients undergoing surgery for benign or malignant thyroid conditions were included based on defined inclusion and exclusion criteria. Data on demographics, clinical history, surgical details, and serial calcium levels were collected using a structured sheet. Standardized surgical techniques were applied, and hypocalcemia was categorized as early (?72 hours) or late (>6 months).

Results: Among thyroidectomy patients in this study, the mean age was 44.79±12.27 years, with females comprising 80.0% of the cohort. Benign diagnoses were more common (60.0%), and near-total thyroidectomy was the predominant procedure (74.1%). Early hypocalcemia occurred in 29.4% of patients, while permanent hypocalcemia was rare (1.2%). Significant differences in serum calcium levels by surgery type were observed at 24 hours (p=0.009) and 7 days postoperatively (p=0.002), with bilateral lobectomy showing higher calcium levels. Early hypocalcemia (p=0.019), normalization time (p=0.013), permanent hypocalcemia (p=0.033), and vitamin D supplementation duration (p=0.004) were all significantly associated with the type of thyroidectomy performed.

Conclusions: Early postoperative hypocalcemia is a common but usually transient complication of thyroidectomy, with permanent cases being rare. The risk and duration of hypocalcemia are significantly influenced by the extent of thyroid resection. More extensive procedures were linked to increased calcium and vitamin D supplementation needs, highlighting the importance of careful surgical technique and early monitoring to reduce hypocalcemia-related complications.

INTRODUCTION

Thyroidectomy, the surgical removal of part or all of the thyroid gland, is commonly performed to treat thyroid cancer, benign nodules, goiters, and hyperthyroidism (1). Surgical approaches were chosen based on disease type, patient condition, and treatment goals. According to the American Association of Endocrine Surgeons (AAES), types of thyroidectomy include total, neartotal, hemithyroidectomy, subtotal, completion, radical, minimally invasive thyroidectomy, and isthmusectomy (27).
Thyroidectomy is indicated for malignant conditions such as papillary, follicular, medullary, or anaplastic thyroid cancers. For hereditary syndromes such as MEN (8), benign indications include compressive nodules, substernal goiters, refractory hyperthyroidism, recurrent nodules, and severe thyroiditis (9).
However, thyroidectomy may be contraindicated in patients with uncontrolled cardiovascular or respiratory diseases, active infections, bleeding disorders, or contraindications to general anesthesia. Relative contraindications, such as unstable thyrotoxicosis, poor health status, and pregnancy, require careful management (10,11).
One of the most significant complications of thyroidectomy is hypocalcemia, primarily due to inadvertent injury or removal of parathyroid glands. Other complications include nerve injury, hemorrhage, thyrotoxic crisis, and voice changes (12). The parathyroid glands maintain calcium homeostasis through the secretion of parathyroid hormone (PTH), which increases calcium levels by promoting bone resorption, renal reabsorption, and vitamin D. Hypocalcemia manifests as neuromuscular symptoms including cramps, paresthesia, seizures, and arrhythmias (13). PTH and calcitriol act synergistically to restore the calcium balance (14).
Hypocalcemia is defined as serum calcium <8.5 mg/dL or ionized calcium <4.5 mg/dL (15). It may occur early (within 48–72 h) or later owing to permanent parathyroid damage. The risk k factors include total thyroidectomy, vitamin D deficiency, and renal disease. Early detection through calcium and parathyroid hormone (PT) H monitoring is essential (16). Globally, transient hypocalcemia affects 20–40% of patients, with permanent hypocalcemia affecting 110% of patients (17). Regional variability is influenced by surgical practice and preoperative care. Management includes calcium and vitamin D supplementation, with recombinant PTH reserved for refractory cases (18).

METHODS

This prospective observational cross sectional study was conducted at the General Surgery Department of Al Nasiriyah Teaching Hospital over one year, from April 1, 2024, to April 1, 2025. This study aimed to evaluate the incidence and characteristics of early and late hypocalcemia after thyroidectomy. All surgeries were performed by experienced general surgeons, using standardized techniques tailored to the disease type and anatomical considerations.
A total of 85 patients undergoing thyroidectomy for benign or malignant thyroid conditions were included. The inclusion criteria were age ?18 years, availability of complete clinical data, and preoperative and postoperative calcium measurements with at least 6 months of followup.
Exclusion criteria included preexisting hypocalcemia, parathyroid disorders, reoperative or completion thyroidectomy, chronic kidney disease, or medications affecting calcium metabolism. Convenience sampling was also conducted.
Data were collected through a structured sheet encompassing demographics, comorbidities, preoperative thyroid function and calcium levels, intraoperative details (type of thyroidectomy, parathyroid, and nerve preservation), and postoperative monitoring (serial calcium levels, supplementation, and complications).
Standard thyroidectomy approaches were used, including subtotal, neartotal, and total thyroidectomy with isthmusectomy. The key surgical steps involved RLN identification, parathyroid gland preservation, and fascial dissection, with bipolar cautery and ligaclips for hemostasis.
Postoperative calcium monitoring was performed at 24 hours and 7 days, with classification into early (within 72 hours) and late hypocalcemia (>6 months). Statistical Analysis Statistical analysis was conducted using SPSS v26, applying descriptive statistics, Chisquare/ Fisher’s exact tests for categorical data, and ANOVA for continuous variables, with p < 0.05 considered significant.

Ethical Approval
Ethical approval was granted by the Scientific and Ethical Committee of the Al Nasiriyah Teaching Hospital and Thi Qar Health Directorate. Informed verbal consent was obtained, confidentiality was maintained, and the participants were free to withdraw at any time.

RESULTS

A total of 85 patients undergoing thyroidectomy were enrolled in this study at the Al Nasiriyah Teaching Hospital. The mean age was 44.79 ± 12.27 years, with the majority (58.8%) in the middleaged group (40 65 years). Females were predominant (80.0%). Regarding comorbidities, 30.6% had hypertension, and 10.6% had diabetes mellitus. Diagnostically, 60.0% of cases were classified as benign, 17.6% as malignant, and 22.4% as suspected or indeterminate. The mean preoperative calcium level was 9.315 ± 0.781 mg/dL (table 1).
Near total thyroidectomy was the most common surgical procedure (74.1%), followed by bilateral lobectomy and subtotal thyroidectomy ( 12.9%) (fig. 1).
Postoperative monitoring revealed that two parathyroid glands were identified in most patients (61.2%). Early hypocalcemia occurred in 29.4% of patients, while permanent hypocalcemia was observed in only one case (1.2%).
Calcium supplementation was required in 29.4% of the patients, with variable durations. Vitamin D supplementation was administered in 23.5% of cases. The mean serum calcium level decreased from 9.01 mg /dL at 24 h postoperatively to 8.36 mg/dL at 7 days. Post operative complications were infrequent, with only 9.4% experiencing any, primarily neuromuscular symp toms (20.0%), including numbness and paresthesia (9.4%). The final histopathology confirmed that 63.5% of the lesions were benign and 36.5% malignant lesions (table 2).
Near total thyroidectomy is more common in middleaged and male patients. Malignancy was predominantly treated with neartotal thyroidectomy.
However, the association between surgery type and demographic variables was not statistically significant (table 3).
Significant postoperative calcium differences were observed between the surgical types at 24 h (p = 0.009) and 7 days (p = 0.002), with bilateral lobectomy associated with higher calcium levels (table 4). Early hypocalcemia was significantly associated with the surgery type (p = 0.019), and the normalization time also differed significantly (p = 0.013). Permanent hypocalcemia was more frequent after subtotal thyroidectomy (p = 0.033). Postoperative complications, although more common in the neartotal group, showed no significant association with surgery type table 5.

DISCUSSION This study provides significant insights into the incidence and predictors of postthyroidectomy hypocalcemia, a common complication that affects patient recovery and longterm outcome.
Neartotal thyroidectomy is the most frequently performed procedure, particularly in middleaged patients. The preference for more extensive surgery in older individuals aligns with the findings of Dhir et al. (19), who reported a tendency to perform total thyroidectomy in older populations due to the increased complexity or size of thyroid disease.
Additionally, males more often underwent near total l thyroidectomy, a trend also noted by Huang et al. (20), who suggested that male patients are more likely to present with more complex thyroid conditions.
Comorbidities such as hypertension and diabetes showed no significant impact, supporting earlier studies by Lee et al. (21) and Song et al. (22), which found that surgical planning is generally based more on thyroidspecific pathology than systemi pathology comorbid conditions.
Changes in perioperative calcium levels are the most critical finding. Although preoperative calcium levels were comparable across the surgical groups (p = 0.099), they emerged in the early and late postoperative periods. At both 24 h and 7 days postsurgery, serum calcium levels were significantly higher in the bilateral lobectomy group than in the neartotal and subtotal groups. These results highlight the association between the extent of surgery and calcium homeostasis, consistent with the findings of Del Rio et al. (23) and Ozemir et al. (24), who reported higher rates of postoperative hypocalcemia following more extensive thyroid resections.
Similarly, El Sayed et al. (25) found a reduced incidence of hypoparathyroidism following subtotal procedures compared to total thyroidectomy, emphasizing the importance of limiting parathyroid manipulation. Furthermore, this study identified the early postoperative period (within 2448 h) as the most critical window for detecting hypocalcemia, which supports the observations made by Hao et al. (26). Regarding parathyroid gland preservation, most patients had two glands identified, with some neartotal and subtotal cases showing only one gland. Although the number of glands identified was not significantly correlated, Riordan et al. (27, and Luo et al. (28) noted that preser e in situ glands are more important than identification alone for predicting postoperative function. A statistically significant association was observed between the surgery type and early hypocalcemia, with the majority of cases occurring after neartotal thyroidectomy. This trend supports the findings of Benmiloud et al. (29) and Rao et al. (30).
Although the type and duration of calcium supplementation were not significant, more extensive procedures required longer supplementation, consistent with the findings of Ahmad et al. (31). Vitamin D use was more frequent and prolonged in these groups, with the duration reaching significance, supporting the conclusions of Benmiloud et al. (29).

CONCLUSIONS

This study highlights the significant clinical implications of hypocalcemia following thyroidectomy. These findings confirm that hypocalcemia is a common complication in the early postoperative period, although it is typically transient and resolves with appropriate management. The extent of thyroid resection was found to be a critical determinant of both the incidence and duration of hypocalcemia, with more extensive procedures, particularly neartotal and subtotal thyroidectomies, associated with a higher risk. Moreover, intraoperative identification of fewer parathyroid glands correlated with increased postoperative calcium disturbances, underscoring the importance of gland preservation during surgery.

Limitations They included a small number of patients, missing PTH values, and a convenience sample, which limits the applicability of the results.

Author’s Contributions Nagham Sharhan; Conceptualization; Data Curation;
Investigation; Methodology; Project administration, Software; Visualization; Writing – original draft, and writing – review and editing. Muhanad Al Ridha; conceptualization; supervision; validation; visualization; writing – original draft and writing – review and editing.

Conflicts of Interest The authors declare no conflict of interest regarding this article.

Funding
None.

REFERENCES

1. Liddy W, Bonilla-Velez J, Triponez F, Kamani D, Randolph G. Principles in thyroid surgery. In: Surgery of the Thyroid and Parathyroid Glands. Elsevier. 2021; p. 272-293.
2. Patel KN, Yip L, Lubitz CC, Grubbs EG, Miller BS, Shen W, et al. The American Association of Endocrine Surgeons guidelines for the definitive surgical management of thyroid disease in adults. Ann Surg. 2020;271(3):e21-e93.
3. Orloff LA, Wiseman SM, Bernet VJ, Fahey III TJ, Shaha AR, Shindo ML, et al. American Thyroid Association statement on postoperative hypoparathyroidism: diagnosis, prevention, and management in adults. Thyroid. 2018;28(7):830-41.
4. Banerjee D, Das PK, Mukherjee J. Nervous System. InTextbook of Veterinary Physiology. Singapore: Springer Nature Singapore. 2023; p. 265-293.
5. Assi MH. Thyroid Gland Basics: A Comprehensive Review. Mustansiriya Medical Journal. 2023;22(2):172-81.
6. Drake FT. Thyroid Gland Anatomy and Physiology. InEndocrine Surgery Clerkship: A Guide for Senior Medical Students. Cham: Springer International Publishing. 2024; p. 11-20.
7. Singh S, Kabra A, Goyal P. Physiological and Therapeutic Role of Calcitonin. Research Journal of Pharmacy and Technology. 2024; 17(4):1881-4.
8. McDonnell JE, Gild ML, Clifton-Bligh RJ, Robinson BG. Multiple endocrine neoplasia: an update. Intern Med J. 2019;49(8):954-961.
9. Kim J, Sosa JA. Looking beyond the cosmetic appeal of transoral thyroidectomy. Br J Surg. 2021;108(8):875-876.
10. Modesti C, Aceto P, Masini L, Lombardi CP, Bellantone R, Sollazzi L. Approach to thyroid carcinoma in pregnancy. Updates Surg. 2017;69(2):261-265.
11. Ravindhran B, Rajan S, Mohan LN. P32: post-operative relative parathormone decline (?pth%) and absolute parathormone decline (?pth) levels are better markers of symptomatic hypocalcemia following total thyroidectomy than post-operative alone. Br J Surg. 2021;108(Supplement_1):znab117-117.
12. Hakeem S. Clinical complications post thyroidectomy. American Journal of Sociology. 2020; 3:159-62.
13. Khan M, Jose A, Sharma S. Physiology, Parathyroid Hormone. In: StatPearls. StatPearls Publishing, Treasure Island (FL); 2023; p. 1-4.
14. Hendy GN, Canaff L. Calcium-sensing receptor, proinflammatory cytokines and calcium homeostasis. In: Seminars in cell & developmental biology. Academic Press. 2016;49:37-43.
15. Potestio CP, Van Helmond N, Azzam N, Mitrev LV, Patel A, Ben-Jacob T. The incidence, degree, and timing of hypocalcemia from massive transfusion: a retrospective review. Cureus. 2022;14(2):1-7.
16. Abdullah AS. The role of early postoperative parathyroid hormone level after total thyroidectomy in prediction of hypocalcemia. Ann Med Surg (Lond). 2021;65:102252.
17. AlQahtani A, Parsyan A, Payne R, Tabah R. Parathyroid hormone levels 1 hour after thyroidectomy: an early predictor of postoperative hypocalcemia. Canadian Journal of Surgery. 2014;57(4):237.
18. Moon H, Seok JW, Kim K, Kim HY, Park MK, Kim IJ, et al. Effectiveness of prophylactic calcium and vitamin D supplementation for preventing post-thyroidectomy hypocalcemia: a metaanalysis. Kosin Medical Journal. 2022;37(3):213-9.
19. Dhir M, McCoy K, Ohori P, Adkisson CD, Lebeau S, Carty S, et al. Correct extent of thyroidectomy is poorly predicted preoperatively by the guidelines of the American Thyroid Association for low and intermediate risk thyroid cancers. Surgery. 2018;163(1):81–6.
20. Huang Y, Chen S, Wang Y, Ou X, Yan H, Gan X, et al. Analyzing Comorbidity Patterns in Patients With Thyroid Disease Using Large- Scale Electronic Medical Records: Network-Based Retrospective Observational Study. Interactive Journal of Medical Research. 2024;13(1):e54891.
21. Lee YK, Hong N, Park SH, Shin DY, Lee C, Kang SW, et al. The relationship of comorbidities to mortality and cause of death in patients with differentiated thyroid carcinoma. Sci Rep. 2019;9:1–9.
22. Song Z, Akhund R, Wu C, Wang R, Lindeman B, Fazendin J, Gillis A, Chen H. From routine to rescue: Thyroidectomy for life-threatening thyrotoxicosis. World J Surg. 2024;48(12):2892-2898.
23. Del Rio P, Rossini M, Montana C, Viani L, Pedrazzi G, Loderer T, et al. Postoperative hypocalcemia: analysis of factors influencing early hypocalcemia development following thyroid surgery. BMC Surg. 2019;18:117.
24. Ozemir I, Buldanl? M, Yener O, Leblebici M, Eren T, Baysal H, et al. Factors affecting postoperative hypocalcemia after thyroid surgery: Importance of incidental parathyroidectomy. North Clin Istanb. 2016;3(1):9-14
25. El-Sayed WM, Elhariri S, Mekhaeel MSF, Burud I. Total Thyroidectomy versus Subtotal Thyroidectomy as a Suitable Surgery for Benign Thyroid Disorders. West Afr J Med. 2024; 41(6):708-713.
26. Hao S, Liu X, Ma J, Li B, Ning J, Wu G, et al. Clinical significance of monitoring drainage fluid parathyroid hormone after thyroid surgery. Chin J Otorhinolaryngol Head Neck Surg. 2018;12:39-42.
27. Riordan F, Murphy MS, Feeley L, Sheahan P. Association between number of parathyroid glands identified during total thyroidectomy and functional parathyroid preservation. Langenbecks Arch Surg. 2021;407:297–303.
28. Luo H, Zhao W, Yang H, Su A, Wang B, Zhu J. In situ preservation fraction of parathyroid gland in thyroidectomy: A cohort retrospective study. Int J Endocrinol. 2018;2018:7493143.
29. Benmiloud F, Godiris-Petit G, Gras R, Gillot J, Turrin N, Pénaranda G, 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.
30. Rao SS, Rao H, Moinuddin Z, Rozario A, Augustine T. Preservation of parathyroid glands during thyroid and neck surgery. Front Endocrinol. 2023;14:1173950.
31. Ahmad R, Sammer S, Khan R, Ghani A, Idrees M, Jadoon WA. Frequency and outcomes of parathyroid preservation in total thyroidectomy. Prof Med J. 2024;31(11):1588-1594.

Full Text Sources:
Abstract:   
Views: 102