Post-thyroidectomy hematoma and hypocalcemia as separate complications: risk factors and management—a systematic review and meta-analysis

Introduction

Thyroidectomy, the surgical removal of all or part of the thyroid gland, is a widely performed procedure indicated for various thyroid conditions, including benign thyroid nodules, multinodular goiters, hyperthyroidism, and thyroid cancer. The procedure is most common among individuals aged 31–40 years (30.1%) and is particularly prevalent in females (1). Thyroidectomy has become one of the most frequently performed surgeries worldwide, carried out by general surgeons, endocrine surgeons, thoracic surgeons, head and neck surgeons, and otolaryngologists. Individuals with thyroid dysfunction, such as hyperthyroidism or hypothyroidism, may require elective or emergency surgical intervention during their lifetime. Despite significant advancements in the safety and effectiveness of thyroidectomy, complication rates still vary. Over recent decades, extensive research has detailed various complications specific to thyroidectomy, including neck hematomas that can lead to airway obstruction, hypocalcemia, and recurrent laryngeal nerve damage resulting in vocal cord paralysis (2).

Post-thyroidectomy hematoma can be a devastating complication of thyroid surgery, occurring with an incidence of 0.7% to 4.7% (3). Hematoma formation typically results from bleeding within the surgical site, leading to the accumulation of blood and subsequent compression of the trachea, which can cause airway obstruction. Clinical presentation may include neck swelling, a choking sensation, neck pressure, respiratory distress, wound drainage, dysphagia, or difficulty with phonation (4). In severe cases, this complication can lead to cerebral anoxia, resulting in major neurological issues and, in extreme cases, death (5,6). The timing of hematoma onset is crucial; it most commonly occurs within the first 24 hours postoperatively, with the majority presenting within the first six hours (7). Management of post-thyroidectomy hematoma involves prompt recognition, emergency airway management, and often surgical evacuation to relieve pressure on the airway (8). Several studies have reported cases of hematoma formation following thyroidectomy. This finding is noteworthy because hematoma is considered an uncommon complication compared to other postoperative issues such as hypocalcemia. While hypocalcemia occurs relatively frequently due to parathyroid gland involvement during surgery, hematoma is observed in a much smaller proportion of patients but carries greater clinical risk because of its potential to cause rapid airway obstruction (9-11).

Post-thyroidectomy hypocalcemia is primarily caused by the inadvertent removal or devascularization of the parathyroid glands, which are crucial for calcium homeostasis. The parathyroid glands regulate serum calcium levels through the secretion of parathyroid hormone (PTH), which increases calcium reabsorption in the kidneys, promotes the release of calcium from bones, and enhances the conversion of vitamin D to its active form, thereby improving calcium absorption in the intestines. When the arterial or venous blood supply to the parathyroid glands is compromised during surgery, hypocalcemia can occur. This impairment can lead to a drop in serum calcium levels, with tetany potentially developing within 12 hours post-surgery (12,13).

The incidence of hypocalcemia after thyroidectomy varies widely in the literature, ranging from 7% to 51% of cases. Six months post-surgery, the prevalence of hypocalcemia is approximately 3.6%, with permanent cases ranging from 1.5% to 4% (14). For patients, post-thyroidectomy hypocalcemia is not merely a transient inconvenience but a significant complication that can affect quality of life, prolong hospital stays, and increase healthcare costs (14). Severe hypocalcemia can lead to acute symptoms such as tetany, seizures, and cardiac arrhythmias, necessitating immediate medical intervention and potentially resulting in prolonged hospitalization (15). The risk of developing hypocalcemia after thyroidectomy is influenced by patient-related factors, disease-related factors, and, most critically, surgical factors such as the extent of thyroidectomy and the surgeon’s experience (16-18). Total thyroidectomy and less experienced surgeons increase the likelihood of hypocalcemia due to the greater risk of parathyroid gland damage.

Post-thyroidectomy hematoma and hypocalcemia are associated with adverse outcomes, warranting attention to their risk factors, prevention, and management. This systematic review aims to analyze and consolidate current research on the risk factors and management strategies for these complications, identify critical predictors, and propose recommendations for improving clinical practice. We present this article in accordance with the PRISMA reporting checklist (available at https://aot.amegroups.com/article/view/10.21037/aot-2025-8/rc).

Methods

Definition of outcomes and inclusion criteria

This systematic review and meta-analysis included studies focusing on adult patients who underwent thyroidectomy, specifically addressing complications such as hematoma and hypocalcemia and their management. Eligible studies concentrated on identifying or analyzing risk factors associated with these complications, as well as those that discussed management, treatment, or prevention strategies for post-thyroidectomy hematoma and hypocalcemia. To ensure relevance and timeliness, only studies published between January, 2010 and December, 2024 were considered. The goal was to compile comprehensive insights into the incidence, risk factors, and effective management strategies for these specific post-thyroidectomy conditions.

We excluded case reports, editorials, opinion papers, and articles not peer-reviewed, as they did not offer sufficiently rigorous evidence for inclusion in this review. Studies were also excluded if they were not in English. Additionally, any study that did not specifically focus on post-thyroidectomy hematoma or hypocalcemia, or those that addressed general postoperative complications without a specific analysis of these conditions, were excluded. Studies involving patients undergoing other types of neck surgeries or procedures unrelated to thyroidectomy were also excluded to maintain a focus on the relevant patient population and surgical context.

Search strategy

We conducted a comprehensive search across electronic databases, including ScienceDirect, PubMed, Scopus, Cochrane Library, and Web of Science for publication. The search utilized a combination of specific keywords and phrases to ensure a comprehensive and targeted retrieval of relevant studies. We used search strategy: (“Post-thyroidectomy hematoma” OR “Cervical hematoma” OR “Neck hematoma” OR “Postoperative hematoma” OR “Surgical site bleeding” OR “Thyroid surgery complications”) AND (“Hypocalcemia” OR “Low calcium levels” OR “Post-thyroidectomy hypocalcemia” OR “Calcium deficiency” OR “Parathyroid dysfunction” OR “Hypoparathyroidism” OR “Parathyroid insufficiency”) AND (“Risk factors” OR “Predictors” OR “Determinants” OR “Associated factors” OR “Preoperative risk” OR “Surgical risk” OR “Postoperative risk” OR “Management” OR “Treatment” OR “Prevention” OR “Intervention”). Reference lists from relevant articles and reviews were also screened to identify further studies that met the inclusion criteria.

Screening and extraction

Articles with unrelated titles were excluded. In the next stage, abstracts and full texts were carefully reviewed to assess compliance with the inclusion criteria. Titles and abstracts were organized and checked for duplicates using Endnote X8. A dual screening method was applied, with one review focusing on titles and abstracts and another on full texts. After identifying the eligible articles, a structured extraction form was developed to record information relevant to the study objectives.

Two reviewers independently conducted screening, data extraction, and quality assessment, resolving any disagreements through discussion. Extracted data included study characteristics such as author, year of publication, country, design, sample size, follow-up duration, and funding sources. Participant details, including age, gender, and nationality, were also recorded. Pooled rates of hematoma and hypocalcemia were analyzed using R software.

Quality assessment

In this review, the Newcastle-Ottawa Scale (NOS) was used to assess the quality of non-randomized studies. The NOS is a well-established tool for evaluating methodological quality and risk of bias in observational research, including cohort and case-control designs. It assesses key elements such as selection of study groups, comparability, and outcome assessment. Applying the NOS allowed for a structured appraisal of included studies, ensuring that only high-quality evidence informed the analysis and strengthening the reliability of the findings.

Statistical analysis

Statistical analysis was performed in R Studio using a proportion meta-analysis to calculate the pooled incidence of hematoma and hypocalcemia. Incidence rates and sample sizes were extracted and prepared for analysis. The meta and metafor packages were used, applying a random-effects model to account for substantial heterogeneity among studies. Heterogeneity was evaluated with the I² statistic and the Chi-squared test, while between-study variance was estimated using Tau-squared (τ²). A forest plot was generated to display individual study estimates alongside the overall pooled incidence.

Results

Search results

The search strategy yielded 303 citations, which decreased to 261 after removing duplicates. Screening titles and abstracts narrowed this to 88 articles meeting the eligibility criteria. Full-text review further refined the selection to 10 studies (19-28) that satisfied the inclusion and exclusion criteria. Figure 1 illustrates the search and screening process in detail.

Figure 1 PRISMA flow chart.

Results of quality assessment

Quality assessment of the ten studies using the NOS indicated that most were high quality, with the majority scoring 9 out of 9. These scores reflect strong compliance with criteria including cohort representativeness, selection of control groups, exposure assessment, and follow-up adequacy. Two studies scored 8, indicating minor limitations in follow-up, cohort representativeness, or exposure assessment. Overall, the findings suggest that the included studies are generally robust, with few minor exceptions (Table 1).

Characteristics of the included studies

The included studies were primarily retrospective cohort designs, with a few prospective cohorts and case series. They were conducted across multiple countries, including the United States, United Kingdom, Sweden, South Korea, China, Brazil, and Denmark. Sample sizes ranged from 182 to over 215,000 patients. Most studies reported a female predominance (males 10–22%) and mean patient ages in the 40s to 50s. Indications for thyroidectomy included benign nodular disease, thyroid cancer, and autoimmune conditions such as Graves’ disease. Total thyroidectomy was the most frequently performed procedure, though hemithyroidectomy and lobectomy were also included. Only one study (de Carvalho et al., Brazil) identified the bleeding source, while others did not report detailed hemorrhage origins or surgical indications. This distribution reflects heterogeneity in study design, populations, and clinical practices across healthcare systems.

The reviewed studies from various countries displayed diverse patient demographics, thyroid disease types, and surgical methods. Al-Hakami et al. (19) and Alqahtani et al. (20) focused on Saudi Arabian patients, with Al-Hakami highlighting a range of thyroid conditions and Alqahtani emphasizing benign and malignant cases. de Carvalho et al. (21) from Brazil and De Palma et al. (22) from Italy provided insights into larger cohorts with Carvalho (21) reporting predominantly malignant cases and De Palma focusing on benign ones. De Berhanu et al. (23) in Ethiopia noted a high rate of near-total thyroidectomies for various goiter types. Mahoney et al. (24) and Mohtashami et al. (25) offered extensive data on thyroidectomy procedures from Hawaii and Canada, respectively. Philippe et al. (26) from France and Rubio et al. (27) from the USA contributed additional perspectives, with Philippe covering benign and malignant conditions and Rubio including a large U.S. cohort. Tongol and Mirasol (28) provided data from the Philippines with fewer details. One study by de Carvalho et al. (21) reported the sources of bleeding as follows: no obvious source in 41.9% of cases (26 patients), followed by the inferior thyroid artery branch in 16.1% (10 patients) and the superior thyroid vessel in 12.9% (8 patients). Other identified sources included the Berry ligament in 8.1% (5 patients), the anterior jugular vein and strap muscle, each accounting for 6.5% (4 patients). Less common sources were thyroid remnant after lobectomy in 3.2% (2 patients), the middle thyroid vein and external jugular vein, each at 1.6% (1 patient), along with other sources of arterial bleeding, also at 1.6% (1 patient) (Table 2).

Hematoma incidence and associated factors

The incidence of post-thyroidectomy hematoma varies across studies, with rates ranging from 0.65% to 4.9%. The meta-analysis results for hematoma incidence reveal a pooled incidence of approximately 1.43% [95% confidence interval (CI): 1.07–1.80%, P<0.0001] across the included studies (Figure 2). The estimated amount of total heterogeneity (τ²) is very low, suggesting that the observed variation in incidence estimates is minimal but not negligible. The high I² value of 88.01% indicates substantial heterogeneity, meaning that a significant portion of the variability in incidence estimates is due to differences between the studies rather than just sampling error. The Q-test for heterogeneity is statistically significant (P<0.0001), confirming the presence of significant variability in the incidence estimates across the studies.

Figure 2 Forest plot of the pooled prevalence of post-thyroidectomy hematoma. RE, random-effect.

Notable risk factors include older age, vitamin D deficiency, and thyroid malignancy. Specific studies highlighted additional risk factors such as age ≥45 years, lymphocytic thyroiditis, and concurrent neck dissection. For instance, de Carvalho et al. (21) identified these factors as significant, while Mahoney et al. (24) emphasized the influence of demographic factors such as male gender and black race, as well as comorbid conditions like hypertension and bleeding disorders. Furthermore, De Berhanu et al. (23) found that total thyroidectomy was a notable risk factor for hematoma.

Hypocalcemia incidence and associated factors

The incidence of post-thyroidectomy hypocalcemia ranged from 4.9% to 65.4%. The meta-analysis results for hypocalcemia incidence indicate a pooled incidence of approximately 23.14% (95% CI: 10.96–35.32%, P=0.0002) (Figure 3). The substantial amount of total heterogeneity (τ²=0.0383) suggests considerable variation between the studies, which is beyond what would be expected by chance alone. This is further supported by the extremely high I² value of 99.97%, indicating that nearly all of the variability in incidence estimates is due to true differences across the studies rather than sampling error. The Q-test for heterogeneity is highly significant (P<0.0001), confirming the presence of significant variability among the studies.

Figure 3 Forest plot of the pooled prevalence of post-thyroidectomy hypocalcemia. RE, random-effect.

Key risk factors identified include older age, gender (with females generally at higher risk), and type of thyroid disease, particularly malignancies. For instance, Al-Hakami et al. (19) and Alqahtani et al. (20) found significant associations between older age, vitamin D deficiency, and total thyroidectomy with increased risk of hypocalcemia. Similarly, De Palma et al. (22) and Philippe et al. (26) reported that total thyroidectomy, as well as specific conditions like Grave’s disease, were significant risk factors. Studies like Rubio et al. (27) and Mohtashami et al. (25) further highlighted that thyroid cancer and Grave’s disease contributed to elevated hypocalcemia risk, reflecting the complex interplay of surgical and disease-related factors (Table 3).

The management strategies for post-thyroidectomy hematoma and hypocalcemia vary across studies, reflecting a range of approaches. For hematoma, common strategies include reoperation for wound hematomas and tracheostomy in cases of significant airway compression. The use of energy devices during surgery and extended hospital stays for observation are also noted to reduce hematoma risk. In contrast, management of hypocalcemia primarily involves calcium and vitamin D supplementation. Intravenous calcium gluconate infusions are used for severe symptomatic cases (Table 4).

Discussion

This study conducted a comprehensive review of existing research to assess the rates of hematoma and hypocalcemia following thyroid surgery. The key findings showed that post-thyroidectomy hematoma was associated with older age, vitamin D deficiency, and thyroid cancer. While hypocalcemia was linked to older age, female sex, and thyroid cancer. Hematoma was managed by reoperation and tracheostomy. Whereas, hypocalcemia was treated using calcium and vitamin D supplements or intravenous calcium.

Strengths and limitations

This study stands out for its inclusion of high-quality studies from a wide range of geographical locations, which enhances the robustness and generalizability of its conclusions. By synthesizing data from multiple reputable sources, the review offers a thorough evaluation of risk factors and management strategies for these complications. Its findings are consistent with existing literature, validating previously observed trends and confirming the effectiveness of various treatment approaches. This alignment not only underscores the study’s reliability but also provides valuable insights into the domain, helping to refine clinical practices and improve patient outcomes. The systematic search methodology and meta-analysis significantly enhance the strength of this study. By systematically searching for and reviewing relevant literature, the study ensures comprehensive coverage of available evidence. The meta-analysis then aggregates and analyzes data from multiple high-quality sources, providing a robust and quantitative synthesis of findings. This rigorous approach minimizes bias, increases the reliability of results, and offers a clearer understanding of post-thyroidectomy complications and their management.

This review encounters several limitations also, which may affect the applicability of the findings. First, the inability to assess preoperative calcium and vitamin D levels due to intrinsic characteristics of the study, followed by variability in the quality and methodologies of included studies, can lead to inconsistent results. Diverse measurement criteria for complications like hematoma and hypocalcemia further complicate the synthesis of results. Additionally, a lack of data on specific patient subgroups, such as comorbid conditions, limits the generalizability of the findings. Variations in follow-up durations can result in incomplete capture of late-onset complications, and inadequate reporting of data in some studies can obscure important details about risk factors and management strategies. Uncontrolled confounding variables, such as differences in surgical expertise or institutional practices, may also impact the observed relationships between risk factors and complications. Lastly, the geographic and institutional contexts of the included studies may affect the external validity of the results, making it challenging to apply findings broadly across different settings. Addressing these limitations in future research can improve the accuracy and relevance of conclusions regarding post-thyroidectomy complications.

Despite these limitations, publishing the study remains crucial since the study provides a valuable synthesis of existing research, offering insights into the incidence and risk factors associated with these complications. By identifying trends and gaps in the current evidence, it can guide future research and help standardize diagnostic and management practices. Publishing this review contributes to the broader medical knowledge base, supporting evidence-based decision-making and enhancing clinical care. It also underscores the need for continued investigation to address identified limitations, ultimately leading to improved patient outcomes and more effective management strategies in thyroid surgery.

A key limitation is that the study by de Carvalho et al. (21) is the only study reporting bleeding sources, which limits the ability to compare findings across different populations and surgical techniques. The lack of additional studies makes it difficult to determine whether the reported distribution of bleeding sites is consistent or influenced by specific methodological factors. This gap in research highlights the need for further studies to validate these findings.

Incidence and analysis of risk factors for hematoma

Findings from this review highlight the incidence of hematoma following thyroid surgery varies between studies, ranging from 0.65% to 4.9%. Meta-analysis shows a combined incidence of approximately 1.43% and risk factors include older age, vitamin D deficiency, and thyroid cancer. Additional factors identified by specific studies include age over 45, lymphocytic thyroiditis, and concurrent neck dissection. Results from included studies also highlight the impact of demographic factors such as male gender and Black ethnicity, along with comorbidities like hypertension and bleeding disorders. Total thyroidectomy has been recognized as a significant risk factor for hematoma. Similarly, another meta-analysis from Liu et al. concluded that post-thyroidectomy hemorrhage occurred in 6,277 patients with an incidence rate of 1.48% (29). Several risk factors for post-thyroidectomy hemorrhage identified, include older age, male sex, Graves’ disease, use of antithrombotic drugs, bilateral operation, neck dissection, and previous thyroid surgery (29). Similarly, a meta-analysis by Fan et al. identified risk factors for neck hematoma requiring surgical re-intervention after thyroidectomy, including male gender, older age, Graves’ disease, hypertension, use of antithrombotic medications, prior thyroid procedures in low-volume hospitals, previous thyroid surgery, bilateral thyroidectomy, and neck dissection (30). Additionally, a database study by Dehal et al. reported an overall incidence of surgical neck hematoma of 1.5% (n=2,210). Multivariate analysis identified several risk factors, including age ≥65 years [odds ratio (OR) =1.8, 95% CI: 1.4–2.1], male sex (OR =1.3, 95% CI: 1.2–1.4), African-American race (OR =1.5, 95% CI: 1.2–1.7), residence in the South (OR =1.3, 95% CI: 1.0–1.4), comorbidity score ≥3 (OR =2.0, 95% CI: 1.6–2.6), history of alcohol abuse (OR =2.7, 95% CI: 1.6–2.5), and Graves’ disease (OR =3.0, 95% CI: 2.1–4.1) (31).

Adding further evidence in this context recent evidence in the form of systematic reviews based on observational studies has identified several risk factors for neck hematoma following thyroidectomy, including age progression, male gender, Graves’ disease, hypertension, anti-thrombotic use, low-volume centres, prior thyroidectomy, and neck dissection (32). Moreover, an Iranian study from the present time reported that 70.7% of the patients were aged 20 to 50 years and almost 1.1% of patients had a hematoma following thyroidectomy (33). Males are more likely to develop hematoma following surgery (P=0.01). Patients with a history of hypertension had a considerably greater hematoma rate (P=0.001). Male gender and age over 50 years were significantly associated with the probability of hematoma (P<0.05). The occurrence of hematoma was statistically significantly associated with follicular thyroid carcinoma pathology (P=0.001). Other pathologic diagnoses were not substantially associated with hematoma formation following thyroidectomy (33). The evidence from the literature is consistent with our findings and reinforces the validity of our results.

Incidence and analysis of risk factors for hypocalcemia

For post-thyroidectomy hypocalcemia, the reported incidence ranges from 4.9% to 65.4%. Meta-analysis indicates a pooled incidence of about 23.14% while risk factors include older age, female gender, and the type of thyroid disease, particularly malignancies. Findings from included studies have shown that older age, vitamin D deficiency, and total thyroidectomy are strongly associated with a higher risk of hypocalcemia. Additionally, thyroid cancer and Graves’ disease further increase the risk of hypocalcemia, demonstrating the complex interplay between surgical factors and underlying health conditions. Similarly, another meta-analysis by Qin et al. indicated that 24.92% (5,716/22,940) had temporary hypocalcemia, while 1.96% (232/11,808) had permanent hypocalcemia (34). Significant predictors (P<0.05) of transient hypocalcemia included female sex, parathyroid autotransplantation, accidental parathyroid removal, Graves’ disease, thyroid cancer, central lymph node dissection, severe preoperative vitamin D deficiency, general preoperative vitamin D deficiency, and lower postoperative 24-hour PTH levels (34). Similarly, a meta-analysis by Chen et al. identified twelve major risk factors for postoperative hypocalcemia: hypoparathyroidism (OR =5.58), total thyroidectomy (OR =3.59), hypomagnesemia (OR =2.85), preoperative vitamin D deficiency (OR =2.32), female sex (OR =1.49), thyroid malignancy (OR =1.85), thyroiditis (OR =1.48), substernal multinodular goiter (OR =1.70), parathyroidectomy (OR =1.58), central compartment neck dissection (OR =1.17), modified radical neck dissection (OR =1.57), and central neck dissection (OR =1.54) (14). Another meta-analysis by Edafe et al. concluded that perioperative PTH, preoperative vitamin D, and postoperative calcium changes are biochemical indicators of post-thyroidectomy hypocalcemia. While female sex, Graves’ disease, the need for parathyroid autotransplantation, and inadvertent parathyroid gland removal are all clinical predictors (35).

Another review indicated that the risk of hypocalcemia is higher in females and increases with the extent of lymph node dissection and type of thyroidectomy, with larger dissections posing greater risk. Interventions for recurrent goiter and repeat procedures for postoperative bleeding also raise the risk. Among benign conditions, Basedow disease carries a higher risk than multinodular goiter. Additional factors include longer procedure duration and preoperative low levels of calcium, PTH, and 25-hydroxyvitamin D (36). Additionally, Noureldine et al. described in their study that low postoperative PTH levels, female sex, and the presence of a malignant tumor are all significant independent predictors of hypocalcemia following total thyroidectomy (37).

Additionally, Kazaure et al. found that patients with severe hypocalcemia experienced higher rates of recurrent laryngeal nerve injury (13.4% vs. 6.6%), unplanned reoperations (4.4% vs. 1.3%), and prolonged hospital stays (≥3 days: 30.4% vs. 6.2%), all statistically significant (P<0.01) (38). After multivariate adjustment, severe hypocalcemia was associated with Graves’ disease, lateral neck dissections, and unplanned reoperations, with all P values below 0.01 (38). While similar to our incidence an analysis by Nair et al. showed that the overall incidence of hypocalcemia was 23.6% (n=190), with permanent hypocalcemia accounting for 1.61% (n=13) (39). In thirteen individuals, onset was delayed until the third postoperative day. Hypocalcemia was substantially linked with thyroidectomy for Graves’ disease (P=0.001), Hashimoto’s thyroiditis (P=0.003), and inadvertent parathyroidectomy (P=0.006). In predicting hypocalcemia, the intraoperative PTH assay demonstrated modest sensitivity (0.5) but good specificity (0.9) (39).

The evidence from existing literature closely aligns with our findings, reinforcing the accuracy and reliability of our results. Our study observed similar rates of hematomas and hypocalcemia as those reported in previous research. This consistency across studies underscores that our outcomes are in line with established patterns and trends. The agreement between our results and the broader body of evidence supports the validity of our findings and suggests that the predictors and risk factors we identified are consistent with those recognized in earlier studies. This convergence of data helps to confirm the robustness of our conclusions about the incidence and determinants of these post-surgical complications.

Management approaches employed for hypocalcemia

There are currently no standardized guidelines for managing calcium levels after thyroidectomy. The literature presents various approaches to treatment, with debates centered on whether to use prophylactic calcium with or without active vitamin D for all patients or to provide selective supplementation based on biochemical markers like calcium and PTH levels. In up to 16% of cases, the discontinuation of supplementation is overlooked, resulting in extended use of supplements and potential misclassification of patients whose parathyroid function has already normalized (40). Results from this study indicate the management of hypocalcemia primarily involves supplementing calcium and vitamin D. In cases with severe symptoms, intravenous calcium gluconate is administered to rapidly restore calcium levels. Similarly, results from a recent meta-analysis showed that in a review of 8 protocols involving 3,806 patients, all individuals received routine calcium and/or active vitamin D immediately after thyroidectomy. In contrast, 49 protocols with 44,012 patients administered these supplements only to those diagnosed with post-thyroidectomy hypoparathyroidism based on biochemical tests. Meanwhile, 10 protocols with 3,278 patients-initiated supplementations only when clinical symptoms of hypocalcemia were observed. No major complications related to postoperative hypocalcemia were reported. The incidence of long-term hypoparathyroidism was 2.4% (95% CI: 1.9–3.0%), with no significant difference in long-term hypoparathyroidism rates among the different supplementation strategies (41). All treatment approaches effectively prevented severe hypocalcemia complications, and the early postoperative management protocol did not significantly affect the long-term recovery of parathyroid function (41). Additionally, findings from another meta-analysis reported that Teriparatide, oral calcium plus vitamin D3, and oral calcium plus activated vitamin D3 all outperform placebo in terms of treating clinical hypocalcemia. Teriparatide proved to be the most effective treatment for symptomatic hypocalcemia, followed by oral calcium plus activated vitamin D3 and oral calcium plus vitamin D3. Intravenous and oral calcium are beneficial in treating biochemical hypocalcemia (42).

Paduraru et al. reported that early postoperative PTH and calcium levels are the most reliable predictors for the need for oral calcium supplementation. Routine administration of calcium and vitamin D postoperatively significantly lowers the risk of transient hypocalcemia and acute complications compared with calcium alone or no supplementation. In cases of hypoparathyroidism, calcitriol is recommended (36). Moreover, Singer et al. suggested that prophylactic calcium supplementation without periodic testing in the laboratory was demonstrated to be a safe and cost-effective approach to prevent and manage postoperative hypocalcemia after total or partial thyroidectomy (43). Results from an analytical study showed that increasing postoperative intact PTH levels by 10 pg/mL reduced the likelihood of severe hypocalcemia by 43% (P<0.001) and hospitalization for more than 24 hours by 18% (P=0.03). Malignant neoplasms were associated with a 27% increased risk of moderate hypocalcemia (P=0.02) (37). For each parathyroid gland that was mistakenly resected or auto transplanted, the likelihood of reduced intraoperative parathyroid hormone (IPTH) levels increased (37).

Additionally, Coerper et al. proposed a treatment protocol for hypocalcemia that involves an initial intravenous dose of 1 g calcium gluconate in 250 mL saline, followed by a risk-based oral regimen of calcium and vitamin D3. Patients were categorized based on their risk levels, with varying doses of calcium and vitamin D3 provided accordingly. This approach, tested in a study of 415 patients, led to significant improvements: serum calcium levels increased within one day, critical hypocalcemia rates dropped from 27% to 12.2%, symptomatic cases decreased from 24.9% to 13.0%, and hospital stays shortened from 10.8% to 6.5% (44). The rate of permanent hypocalcemia remained stable at around 2%. This regimen effectively reduced symptoms and provided clear differentiation in treatment based on risk levels (44). All these studies strongly support the therapeutic strategies analyzed in this review.

Management approaches employed for hematoma

Neck hematomas are rare but possibly fatal complications of thyroid surgery. Postoperative monitoring, early identification, and prompt treatment are crucial since this syndrome may swiftly result in upper airway compression and obstruction (45). Results from our review demonstrate that the strategies for managing hematomas and hypocalcemia after thyroid surgery differ among studies, highlighting various methods for addressing these complications. For hematomas, typical approaches include performing reoperation to address wound-related hematomas and using tracheostomy when there is severe airway compression. Additionally, employing energy devices during the surgery and extending hospital stays for close monitoring are recommended practices to lower the risk of developing hematomas.

Similarly, Thakkar et al. noted that neck hematoma is a primary reason for reoperation, highlighting the need for careful monitoring and timely intervention after thyroid surgery. Management depends on symptom severity, with many cases requiring surgical exploration and evacuation, while immediate bedside evacuation is performed for unstable or rapidly progressing hematomas (8). Other management strategies include manual aspiration, hemostatic agents, blood transfusions for significant bleeding, and compression measures. Surgical treatment of post-thyroidectomy neck hematomas focuses on urgent airway protection if compromised. The hematoma’s size and extent are assessed through clinical evaluation, including physical examination, vital signs, and overall patient status. Small hematomas that do not threaten the airway may be managed with needle aspiration, whereas larger or unresponsive hematomas require surgical evacuation (8).

However, Pontin et al. emphasized that postoperative bleeding after thyroid surgery is unpredictable and cannot be fully prevented, even with recognized risk factors. Key measures include: (I) meticulous hemostasis and surgical technique; (II) close coordination with the anesthesiologist to manage intraoperative factors such as the Valsalva maneuver and maintain stable blood pressure perioperatively; and (III) rapid intervention in the event of bleeding. Intensive monitoring in a recovery area with trained staff for at least 4–6 hours is essential, as early detection and prompt management are critical for optimal outcomes (46). While Lorenz et al. considered that despite the anticipated improvement in postoperative hemorrhage rates due to the growing use of coagulation-related medications, there has been no corresponding decrease in the incidence of complications such as recurrent vocal cord paresis, tracheotomy, and mortality. Successful surgical outcomes are influenced by careful technique and vigilance, along with thorough and qualified postoperative monitoring for at least 4–6 hours. This approach allows for prompt intervention and revision surgery if necessary (47). Moreover, Liff et al. supported a multidisciplinary approach to managing suspected hematomas following thyroid surgery includes oxygenation and assessment, hematoma evacuation, and tracheal intubation (9).

This shows that the management of hematomas is highly individualized, reflecting the diversity of patient conditions, surgeon preferences, and institutional protocols. Each patient’s unique characteristics, such as the size and location of the hematoma, their overall health, and any underlying medical conditions, significantly impact the treatment approach. Surgeons may adopt different strategies based on their expertise, experience, and preferred techniques. Additionally, healthcare institutions have specific protocols and guidelines that shape the treatment process, which can vary based on available resources and institutional practices. Therefore, managing a hematoma involves a complex interplay of these factors, ensuring that the approach is tailored to the specific needs of each patient while adhering to established medical standards and practices.

This study stands out for its inclusion of high-quality studies from a wide range of geographical locations, which enhances the robustness and generalizability of its conclusions. By synthesizing data from multiple reputable sources, the review offers a thorough evaluation of risk factors and management strategies for these complications. Its findings are consistent with existing literature, validating previously observed trends and confirming the effectiveness of various treatment approaches. This alignment not only underscores the study’s reliability but also provides valuable insights into the domain, helping to refine clinical practices and improve patient outcomes. The systematic search methodology and meta-analysis significantly enhance the strength of this study. By systematically searching for and reviewing relevant literature, the study ensures comprehensive coverage of available evidence. The meta-analysis then aggregates and analyzes data from multiple high-quality sources, providing a robust and quantitative synthesis of findings. This rigorous approach minimizes bias, increases the reliability of results, and offers a clearer understanding of post-thyroidectomy complications and their management.

Future research directions

Future research should prioritize several key areas to enhance clinical understanding and practice. Standardizing definitions and diagnostic criteria for complications like hematoma and hypocalcemia will improve the consistency and comparability of findings across studies. Investigating how specific patient characteristics, such as age, gender, and existing health conditions, influence complication rates can refine risk assessment and inform personalized prevention strategies. Additionally, examining the effectiveness of various surgical techniques and hemostatic technologies, including energy devices, in reducing complications is crucial. Long-term studies with extended follow-up are needed to capture late-onset complications and assess long-term outcomes. Research should also focus on the impact of preoperative and postoperative interventions, especially addressing vitamin D levels and overall nutritional status, to develop effective preventive measures. Finally, evaluating the role of surgeon experience and institutional practices in influencing complication rates can help establish best practices and enhance training. Addressing these research directions will improve patient management and outcomes in post-thyroidectomy care.

Conclusions

This study reveals that post-thyroidectomy hypocalcemia has a pooled incidence of approximately 23.14%, while risk factors determined are older age, female gender, and thyroid malignancies. Hematoma incidence ranges from 0.65% to 4.9%, with management often involving reoperation or tracheostomy. Hypocalcemia is primarily treated with calcium and vitamin D supplementation, and severe cases may require intravenous calcium gluconate. Future research should investigate the factors contributing to the variability in incidence rates, develop more effective prevention strategies, and evaluate the impact of new surgical techniques and technologies on the management of post-thyroidectomy complications to enhance patient outcomes.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the PRISMA reporting checklist. Available at https://aot.amegroups.com/article/view/10.21037/aot-2025-8/rc

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