Predictors of permanent hypoparathyroidism following total thyroidectomy: a retrospective analysis

Postoperative hypoparathyroidism is the most frequent complication after total thyroidectomy. The identification of preoperative predictors could be helpful to identify patients at risk. The aim of this study is to determine if preoperative vitamin D levels are related to transient, protracted, and permanent hypoparathyroidism. A prospective, observational study that includes 100 patients who underwent total thyroidectomy. Transient hypoparathyroidism was present in 42% of patients, 11% developed protracted hypoparathyroidism and 5% permanent hypoparathyroidism. The median preoperative Vitamin D levels were higher in patients who developed transient hypoparathyroidism than in patients without this complication (24 ng/mL [RIQ 13-31] vs. 17 ng/mL [RIQ 10-24]; p = 0.024). Patients with preoperative vitamin D levels below 20 ng/mL had a lower percentage of transient hypoparathyroidism (31.4% vs. 53.1%; p = 0.028). The prevalence of protracted and permanent hypoparathyroidism in both groups was similar. Patients with preoperative vitamin D levels lower than 20 pg/mL had higher median PTH levels 24h after surgery, (37.7 ± 28.2 pg/ml vs. 23.6 ± 18.6 pg/ml; p = 0.037), and suffered a lower postoperative PTH decline (46.2 ± 35.4% vs. 61 ± 29%; p = 0.026). Patients with vitamin D deficiency had a lower transient hypoparathyroidism rate, higher median PTH levels 24h after surgery and a lower postoperative PTH decline. We found no association between preoperative vitamin D and the development of protracted or permanent hypoparathyroidism.

Thyroid surgery may lead to postoperative complications. The aim of this paper was to determine whether the rate of postoperative hypoparathyroidism (HPT) is influenced by whether surgery is staged. Single-institution retrospective observational study. The clinical records of 786 patients treated at the Otolaryngology Unit of the Azienda USL-IRCCS di Reggio Emilia between January 1990 and December 2015 were reviewed. Patients were divided into two groups according to the surgical treatment received: group TT (637 patients, 81.04%) underwent single-stage total thyroidectomy; Group cT (149 patients, 18.96%) underwent loboisthmusectomy and delayed completion total thyroidectomy. Transient and permanent HPT, assessed after 6 months of follow-up, were the primary endpoints. Risk factors of postoperative HPT were also analysed as secondary outcomes. Rates of transient HPT in group TT were higher than those observed in group cT, (P = 0.0057). Analysis of risk factors identified sex as an independent risk factor for transient HPT only for group TT (P = 0.0012) and the number of parathyroid glands remaining in situ (PGRIS) as an independent risk factor for transient and permanent HPT for group TT (P < 0.0001 and P = 0.0002, respectively). This study suggests that the risk of transient postoperative HPT is lower in patients that undergo completion thyroidectomy. Further independent risk factors for postoperative HPT are female sex and PGRIS score. In light of the growing use of conservative surgery for thyroid neoplasms, these findings could help to adequately plan surgery in order to reduce endocrine complications.

Background/Objectives: Hypoparathyroidism (HPT) is a common complication following thyroid surgery with an incidence reaching up to 29%, potentially resulting in significant long-term morbidity. To improve its early identification and patient outcomes, we investigated the prevalence and predictors of postoperative HPT. Methods: This retrospective, multicenter observational study included patients who underwent thyroid surgery from 2016 to 2022 in four centers located in Saudi Arabia's Eastern Province. We analyzed demographic data, underlying thyroid or parathyroid conditions, surgical indications, types of procedures, pathology results, and preoperative corrected calcium and vitamin D levels, along with postoperative corrected calcium and parathyroid hormone (PTH) levels. For data analysis, IBM Statistical Package for the Social Sciences (SPSS) Statistics 22 was used, with categorical variables presented as frequencies/percentages and non-normal continuous variables as the median/first quartile (Q1) and third quartile (Q3). Associations were tested with chi-square/Fisher exact tests, medians with Mann-Whitney U-tests, and odds ratios (ORs) with 95% confidence intervals (CIs) via multivariate analysis with statistical significance set at p < 0.05. Results: A total of 679 cases were included. The median age of patients was 43 years (with 48.9% of them aged 41-60 years), and 82% were female. HPT occurred in 228 cases (35.3%), with 115 (81.0%) experiencing transient HPT and 27 (19.0%) permanent HPT. Multivariate analysis identified total thyroidectomy (OR 2.7, p = 0.005), completion thyroidectomy (OR 8.4, p = 0.004), and low immediate postoperative PTH level (OR 3.1, p < 0.001) as independent predictors of HPT. Central lymph node dissection (CLND; OR 4.03, p = 0.004) and low postoperative PTH level (OR 2.56, p = 0.049) were significant predictors of permanent HPT. Conclusions: Key predictors of HPT include surgical extent and low postoperative PTH level, while CLND and low postoperative PTH level are the strongest predictors of permanent HPT. Careful assessment of these risks when determining the extent of surgery and avoiding unnecessary aggressive procedures can help to minimize the occurrence of HPT. Measuring the PTH level immediately after surgery may aid in identifying high-risk patients for early intervention and appropriate follow-up.

Parathyroid Hormone as a Predictor for Calcium Replacement after Total or Completion Thyroidectomy

Hypocalcemia is a well-known complication after total thyroidectomy. Studies have indicated that the presence of low postoperative parathyroid hormone (PTH) levels can predict hypocalcemia. However, definitive study designs are lacking. The aim of this study was to determine whether postoperative PTH alone can accurately predict postoperative biochemical hypocalcemia. Under IRB approval, a prospective study of 218 consecutive patients who underwent total or completion thyroidectomy by two surgeons between June 2014 and June 2016 was performed. Biochemical hypocalcemia was defined as ionized calcium <1.13mmol/L or serum calcium <8.4mg/dL at any time postoperatively. Three PTH thresholds, <10, <20pg/mL, and >50% drop in PTH 1h postoperatively from baseline were examined. Postoperative PTH<10pg/mL had a sensitivity of 36.5% (95% CI 27.4-46.3%) and a specificity of 89.2% (95% CI 81.9-94.3%). Postoperative PTH<20pg/mL had a sensitivity of 66.4% (95% CI 56.6-75.2%) and a specificity of 67.6% (95% CI 58.0-76.2%). Postoperative PTH decrease >50% had a sensitivity of 63.4% (95% CI 53.2-72.7%) and a specificity of 72.5% (95% CI 62.5-81.0%). Across all PTH thresholds, the false-negative rate was 33.6-63.5% indicating that up to 64% of patients with a normal PTH level could have been discharged without appropriate calcium supplementation. The false-positive rate was 10.8-32.4% indicating that up to 32.4% of patients with low PTH could have been treated with calcium supplementation unnecessarily. Following total thyroidectomy, PTH levels are unreliable in predicting hypocalcemia. Additional prospective studies are needed to understand the true utility of PTH levels post-thyroidectomy.

Postoperative hypoparathyroidism after total thyroidectomy for thyroid cancer

Postoperative hypoparathyroidism remains a common complication following total thyroidectomy. Although anatomical preservation of the parathyroid glands (PGs) is routinely attempted, functional outcomes are often unpredictable. To address this gap, we developed a novel physiology-based model to predict postoperative parathyroid hormone (PTH) levels by incorporating preoperative hormonal status and intraoperative perfusion assessment using indocyanine green (ICG) angiography. This retrospective study included 37 patients who underwent bilateral axillo-breast approach robotic total thyroidectomy between July 2024 and February 2025. Intraoperative ICG angiography was used to classify each PG as well-perfused, poorly perfused, or unidentifiable. Based on our hypotheses that each PG contributes to total PTH levels equally under normal physiology and that PG's functional viability can be evaluated by ICG angiography, postoperative PTH levels were calculated using the following formula: Calculated PTH = (Preoperative PTH ÷ 4 × nwell) + (1 × npoor), where nwell and npoor represent the number of well- and poorly perfused PGs, respectively. Postoperative-to-preoperative PTH ratios exhibited distinct clustering at 0.25, 0.50, and 0.75, consistent with the hypothesis that each PG contributes approximately one-quarter to overall PTH production. Calculated PTH values were strongly correlated with measured postoperative levels (Spearman's ρ = 0.60, p < 0.001), and 73.0% of patients had calculated values within ± 5pg/mL of the actual result. Transient hypoparathyroidism occurred in 13 patients (35.1%) and was associated with significantly lower actual and calculated postoperative PTH levels compared to those without hypoparathyroidism. Our physiology-based model enables accurate intraoperative estimation of postoperative PTH levels by incorporating preoperative PTH values and ICG angiography-based perfusion status. This approach may serve as a rapid and effective indicator of post-thyroidectomy hypoparathyroidism, particularly in day surgery settings or in institutions where routine postoperative laboratory monitoring is not feasible.

Objective To predict the occurrence of hypoparathyroidism following total thyroidectomy. Methods In this study, 124 patients underwent total thyroidectomy, 46 for thyroid cancer and 78 for multinodular goiter, additional neck dissection was performed on cancer patients. Serum calcium and parathyroid hormone (PTH) levels were examined preoperatively and at 1 h, 1 d and 2 d postoperatively. The occurrence of postoperative hypoparathyroidism was observed. Receiver operating characteristic curve analysis was employed to identify the best indicator to early predict the occurrence of clinical hypocalcemic symptoms. Results Fifty-eight (46.8%) patients suffered from postoperative transient hypoparathyroidism, with 22 ( 47. 8% ) cases in thyroid cancer group and 36 ( 46. 2% ) in multinodular goiter group ( λ2 = 0. 033, P = 0. 857). One (0.8%) patient in cancer group had permanent hypoparathyroidism. 90 patients (72.6%) had postoperative hypocalcaemia, 58 (46. 8% ) had subnormal serum PTH levels, 40 (32. 3% ) had hypocalcaemia symptoms. Postoperative serum calcium (F=21. 358,P =0. 000) and PTH ( F = 18.253, P =0.000) levels decreased more in cancer group than in goiter group.Receiver operating characteristic curve analysis demonstrated that the percentage of serum PTH level decline at 1 h postoperatively was most predictive and 76. 6% decline was the best cut-off value for the occurrence of clinical hypocalcaemia symptoms ( area under the curve being 0.933 ) with a sensitivity of 89. 7% and a specificity of 87.9%. Conclusions Neck dissection added to total thyroidectomy can decrease the postoperative serum calcium and PTH levels more seriously, but may not increase the incidence of postoperative transient hyperparathyroidism. The percentage of serum PTH level decline at 1 h postoperatively predicts the occurrence of clinical hypocalcaemia symptoms. Key words: Thyroidectomy; Postoperative complications; Hypoparathyroidism; Hypocalcemia

Determinación de paratirina en suero como factor predictivo de hipocalcemia tras tiroidectomía total

Hypocalcemia is the most common complication after total thyroidectomy. The aim of this study was to determine whether postoperative parathyroid hormone (PTH) levels predict hypocalcemia in order to design an algorithm for early discharge. We present a prospective study including patients who underwent total thyroidectomy. Hypocalcemia was defined as serum ionized calcium < 1.09 mmol/L or clinical evidence of hypocalcemia. PTH measurement was performed preoperatively and at 1, 3, and 6 h postoperatively. The percent decline of preoperative values was calculated for each time point. One hundred and six patients were included. Thirty-six (33.9%) patients presented hypocalcemia. A 50% decline in PTH levels at 3 h postoperatively showed the highest sensitivity and specificity to predict hypocalcemia (91 and 73%, respectively). No patients with a decrease <35% developed hypocalcemia (100% sensitivity), and all patients with a decrease >80% had hypocalcemia (100% specificity). PTH determination at 3 h postoperatively is a reliable predictor of hypocalcemia. According to the proposed algorithm, patients with less than 80% drop in PTH levels can be safely discharged the day of the surgery.

Background: The identification and preservation of parathyroid glands (PT) with its intact blood supply is of utmost importance during thyroid surgery. To preserve the PT with intact blood supply, a medial to lateral dissection is advocated, with plane of dissection along the thyroid capsule. One of the earliest and feared complications of thyroidectomy is hypoparathyroidism (HPT). Aim was to study the incidence of temporary and permanent hypoparathyroidism during thyroidectomy.Methods: This was a hospital based prospective study, from 2008 to 2015. 472 cases who underwent thyroidectomy (182 near total and 290 total thyroidectomies) for any indications in general surgery department of a tertiary care centre were included.Results: The incidence of permanent and transient HPT after total thyroidectomy was 3.8 and 09%, where as it was 2.75 and 3.85% after near total thyroidectomy. The results of present study were comparable with other studies.Conclusions: Meticulous dissection, absolute hemostasis, and a thorough knowledge of neck anatomy are the key in reducing the post thyroidectomy complications. Transient or permanent hypo parathyroidism is due to inadvertent gland removal or injury to its vascular pedicle. Dissection close to the thyroid capsule and ligation of capsular branches of thyroid avoiding the main trunk of inferior thyroid artery holds the key.

Objective To investigate the risk factors of hypoparathyroidism after total thyroidectomy and bilateral central lymph node dissection in patients with papillary thyroid carcinoma. Methods Data of patients with PTC who accepted total thyroidectomy and bilateral central lymph node dissection in the Department of Thyroid Surgery from Jan. 2013 to Jun. 2016 were collected and analyzed retrospectively. The patients were divided into normal group, transient hypoparathyroidism group and permanent hypoparathyroidism group according to the level of serum parathyroid hormone within 6 months after surgery. Clinical data were collected for comparison between the three groups. The risk factors of hypoparathyroidism were indentified with univariate analysis and multivariate analysis. Results A total of 468 patients, 241 in the normal group and 227 in the hypoparathyroidism group (220 in the transient hypoparathyroidism group and 7 in the permanent hypoparathyroidism group) , were included in the study. Univariate analysis showed that without application of carbon nanoparticles (P=0.04) and autotransplantation of more than one parathyroid gland (P<0.001) were risk factors of hypoparathyroidism, and without application of carbon nanoparticles (P=0.047) , incidental parathyroidectomy of one parathyroid gland (P=0.04) , gross extrathyroidal extension (P=0.006) and cN1a were risk factors of permanent hypoparathyroidism. Multivariate analysis showed that without application of carbon nanoparticles (OR, 0.437; 95% CI, 0.243-0.789; P=0.006) and autotransplantation of more than one parathyroid gland (OR, 3.025; 95% CI, 1.999-4.579; P=0.000) were independent risk factors of hypoparathyroidism, and without application of carbon nanoparticles (OR, 0.197; 95% CI, 0.039-0.982; P=0.048) and gross extrathyroidal extension (OR, 12.381; 95% CI, 1.432-107.036; P=0.022) were independent risk factors of permanent hypoparathyroidism. Conclusion When total thyroidectomy and bilateral central lymph nodes dissection were performed, carbon nanoparticles were routinely applied. Although autotransplantation of more than one parathyroid gland can increase the incidence of transient hypoparathyroidism, it can reduce the incidence of permanent hypoparathyroidism. If extrathyroidal extension is suspected, hypoparathyroidism should be emphasized to patient, and accurate operation should be done to reduce the incidence of hypoparathyroidism. Key words: Papillary thyroid carcinoma; Hypoparathyroidism; Carbon nanoparticles; Lymph nodes dissection

Hypoparathyroidism (hypoPT) is the most common complication following bilateral thyroid operations. Thyroid surgeons must employ strategies for minimizing and preventing post-thyroidectomy hypoPT. The objective of this American Thyroid Association Surgical Affairs Committee Statement is to provide an overview of its diagnosis, prevention, and treatment. HypoPT occurs when a low intact parathyroid hormone (PTH) level is accompanied by hypocalcemia. Risk factors for post-thyroidectomy hypoPT include bilateral thyroid operations, autoimmune thyroid disease, central neck dissection, substernal goiter, surgeon inexperience, and malabsorptive conditions. Medical and surgical strategies to minimize perioperative hypoPT include optimizing vitamin D levels, preserving parathyroid blood supply, and autotransplanting ischemic parathyroid glands. Measurement of intraoperative or early postoperative intact PTH levels following thyroidectomy can help guide patient management. In general, a postoperative PTH level <15 pg/mL indicates increased risk for acute hypoPT. Effective management of mild to moderate potential or actual postoperative hypoPT can be achieved by administering either empiric/prophylactic oral calcium and vitamin D, selective oral calcium, and vitamin D based on rapid postoperative PTH level(s), or serial serum calcium levels as a guide. Monitoring for rebound hypercalcemia is necessary to avoid metabolic and renal complications. For more severe hypocalcemia, inpatient management may be necessary. Permanent hypoPT has long-term consequences for both objective and subjective well-being, and should be prevented whenever possible.

Permanent hypoparathyroidism, a feared thyroidectomy complication, leads to significant patient morbidity, medical treatment, and monitoring. This study explores whether preoperative high-dose vitamin D loading decreases the incidence of permanent hypoparathyroidism. In a subgroup analysis, the study examines the predictive utility of day 1 parathyroid hormone (PTH) in permanent hypoparathyroidism. Patients (n = 150) were previously recruited in the VItamin D In Thyroidectomy (VIDIT) trial, a multicentre, randomised, double blind, placebo-controlled trial evaluating the role of 300,000 IU cholecalciferol administered orally a week before total thyroidectomy. Patients were contacted postoperatively beyond six months through a telephonic questionnaire. The primary outcome was permanent hypoparathyroidism, strictly defined as the need for activated vitamin D six months postoperatively. Out of 150 patients, 130 (86.7%) were contactable. Permanent hypoparathyroidism occurred in 11/130 (8.5%) patients, with a lower incidence of 5.3% (3/57) in the cholecalciferol group compared to 11% (8/73) in the placebo group; however, this was non-significant (p = 0.34). In a subgroup analysis, no relationship between day 1 PTH level and the incidence of permanent hypoparathyroidism was found (p ≥ 0.99). There was a lower rate of permanent hypoparathyroidism in the cholecalciferol group, which was not significant. The predictive utility of day 1 postoperative PTH levels may be limited to transient hypoparathyroidism.

Thyroid cancer diagnoses are often discovered after diagnostic thyroid lobectomy. Completion thyroidectomy (CT) may be indicated for intermediate or high-risk tumors to facilitate surveillance and/or adjuvant treatment. The completeness of thyroid resection and the safety of CT compared to total thyroidectomy (TT) is unclear. We assessed outcomes after TT or CT to determine completeness of resection and risk of complications. Patients undergoing TT or CT between 2000 and 2018 were retrospectively reviewed. Pathology, unstimulated thyroglobulin (uTg), parathyroid hormone (PTH), rates of hematoma, and recurrent laryngeal nerve (RLN) injury were compared. Differentiated thyroid cancer (DTC) was identified in 954 patients undergoing TT and 142 patients undergoing CT. Postoperative uTg at 6 months was not different between TT and CT, 0.2 vs 0.2 ng/mL, P = .37. Transient hypoparathyroidism with immediate postoperative PTH less than 10 was more common after TT, 14.3 vs 6.0% (P = .009). No differences were noted regarding postoperative hematoma, transient RLN injury, permanent hypoparathyroidism, and permanent RLN injury. If CT is required for DTC, a complete resection, as assessed by postoperative uTg, can be achieved. Furthermore, CT is significantly less likely to result in transient hypoparathyroidism and poses no additional risk of RLN injury, hematoma, or permanent hypoparathyroidism.