Factors affecting postoperative hypocalcemia after thyroid surgery: Importance of incidental parathyroidectomy

The analysis of risk factors for accidental parathyroid resection during thyroid surgery: a retrospective analysis of 1775 patients

PURPOSE

The present study discussed the effects of accidental parathyroid resection on hypoparathyroidism and investigated the risk factors associated with accidental parathyroid resection.

METHODS

Clinical data from patients who have undergone thyroidectomy at a university hospital in the period from November 2018 and October 2020 were entered into the database and analyzed. Risk factors for accidental parathyroid resection were recorded.

RESULTS

A total of 1775 cases were included in this study. The analysis showed that lymph-node dissection (p < 0.001), T staging (p = 0.037), and treatment group (p < 0.001) were independent risk factors for accidental parathyroid resection. Different treatment groups were important risk factors for accidental parathyroid resection. There were significant differences between the professional and non-professional groups in the following aspects: accidental parathyroid resection (p < 0.001), Scope (p < 0.001), T stage (p = 0.009), N stage (p < 0.001), range of lymph-node dissection (p < 0.001), number of lymph nodes dissected in central area (p < 0.001), and number of lymph-node metastases in the central region (p < 0.001).

CONCLUSIONS

The causes of accidental parathyroid resection are multifactorial. The predictors for accidental parathyroid resection include lymph-node dissection in the central region, T staging, as well as the operating surgeons' experience.

Assessment of Serum Ionized Calcium in the Perioperative Period in Patients Undergoing Total Thyroidectomy

BACKGROUND: The serious complications of total and near-total thyroidectomy vary from hypocalcemia to recurrent laryngeal nerve injury to tension hematoma. Post-operative hypocalcemia is common and has an incidence of 1.3–83% in some studies. AIM: The aim of the study is to evaluate the immediate post-operative sequence of serum-ionized calcium next to entire or close entire thyroidectomy to describe the incidence degree of hypocalcemia. METHOD: One hundred and seventy-four (174) patients who underwent total and near-total thyroidectomy were investigated for serum-ionized calcium level preoperatively and on post-operative day (POD) 1 and 2, searching for difference in serum-ionized calcium level preoperatively. RESULTS: There was a significant difference between pre-operative serum-ionized calcium (Ca++) level and that in POD1. The mean pre-operative ionized Ca was 1.23 ± 0.47 mmol/l, while mean ionized Ca on POD1 was 1.175 ± 0.11 mmol/l proposing decrease in mean of ionized Ca++ in POD1 (p = 0.0001). There was also a significant difference between pre-operative serum-ionized Ca++ level and that in POD2. The mean pre-operative ionized Ca was 1.23 ± 0.47 mmol/l, while the mean of ionized calcium on POD2 was 1.177 ± 0.1 mmol/l suggesting decrease in mean concentration of Ca++ in POD2 (p = 0.0001). CONCLUSION: Significant number of patients who undergo near-total and total thyroidectomy develop decrease in the serum concentration of calcium postoperatively.

PTH after Thyroidectomy as a Predictor of Post-Operative Hypocalcemia

Post-thyroidectomy hypocalcemia is a frequent complication with significant morbidity, and has been shown to increase hospital stay and readmission rates. The evaluation of serum parathyroid hormone (PTH) levels after thyroidectomy represents a reliable method to predict post-thyroidectomy hypocalcemia, but it remains infrequently used. This retrospective study investigates serum PTH values 3 h after thyroidectomy as a predictor of hypocalcemia. In this study, we enrolled 141 patients aged between 27 and 71 years eligible for total thyroidectomy who presented with multinodular goiter, suspicious nodule on cytological examination, Graves’ disease, or toxic multinodular goiter. Three hours after total thyroidectomy, 53 patients (37.6%) showed a reduction in serum PTH. Of these patients 75.5% developed hypocalcemia by 24 h after surgery and 100% were hypocalcemic after 48 h (p < 0.001). There was no significant difference attributable to the different thyroid diseases, nor to the age of the patients. PTH at 3 h after total thyroidectomy accurately predicts post-operative hypocalcemia. The early detection of patients at risk of developing post-operative hypocalcemia allows for prompt supplementation of calcium and Vitamin D in order to prevent symptoms and allows for a safe and timely discharge.

Role of perioperative parathormone hormone level assay after total thyroidectomy as a predictor of transient and permanent hypocalcemia: Prospective study

BACKGROUND

The researchers are trying to evaluate the measurement of: Intact parathyroid hormone (iPTH) and serum total calcium (sCa) levels for predicting hypocalcemia after total thyroidectomy (TT).

METHODS

The sample of this single center prospective study consists of (100) patients, where (77) females and (23) males with an age range between (28) and (65) (the mean level is, 48.17 ± 6.54). These selected patients underwent total thyroidectomy (TT) in the general surgery department, Benha university hospital from the period of June 2019 to February 2020. Levels of sCa and iPTH were measured aat several times preoperatively, 10 min, 48 h, 3, 6, 9 months, and 1 year after being after gone TT.

RESULTS

Among the entire study sample, 23 patients (23%) developed transient hypoparathyroidism and hypocalcemia (˂8.5 mg/dl), none of them developed permanent hypoparathyroidism and hypocalcemia. The cut-off point of PTH has been 10 min after TT was at 23 pg/mL as it was the best compromise between sensitivity and specificity for predicting hypocalcaemia. It has been found that Patients who have a PTH greater than 23 pg/mL can be discharged safely after 24 h. Patients who have PTH of less than 23 pg/mL were observed for an additional 24 h, and the study found that timely treatment initiation is recommended. A PTH ˂ 10 pg/mL measured at 48 h after surgery had a sensitivity, specificity as well as an accuracy of 100%, for predicting hypocalcemia after TT. The accuracy of a single PTH concentration at 48 h was useful for predicting hypocalcemia [Area under receiver-operator characteristic curve (AUC) 1; confidence interval (CI), 95%, 0.85-0.94].

CONCLUSION

Patients with iPTH ˂ 10 pg/mL, and sCa levels ˂ 7.4 mg/dL are at higher risk of developing hypoparathyroidism and hypocalcemia after TT.

Is hemithyroidectomy sufficient in unilateral benign nodular goitre?

BACKGROUND

Multinodular goiter is a common disease. If only one thyroid lobe is affected, hemithyroidectomy may be preferred to reduce complication and hormone replacement therapy. However, completion thyroidectomy may be required later. The aim of the study was to evaluate the role of completion thyroidectomy in patients who develop nodules after hemithyroidectomy, and we aimed to find the ratio of patients who required hormone replacement for permanent hypothyroidism.

METHODS

Patients who underwent hemithyroidectomy for benign nodular goitre between January 2012 and June 2017 were analyzed. The age of the patients, gender, number of nodules and dimension of the largest nodule, preoperative fine needle aspiration biopsy results, and postoperative histopathology findings were recorded. The need for completion thyroidectomy and need for postoperative L-thyroxine treatment were based on these parameters.

RESULTS

A total of 170 patients were included in the study. During the follow-up period new nodule or progression in existing nodule was observed in 23% (39 patients) of the cases. Permanent hypothyroidism requiring L-thyroxine treatment was observed in 31% (53 patients) of the cases. In this study, young age, multiple nodules and toxic nodular goitre diagnosis were noted to be independent risk factors that contributed to progression diseases in cases operated for benign nodular goitre.

CONCLUSIONS

Due to low reoperation risk and acceptable permanent hypothyroidism rates, hemithyroidectomy is a viable option for benign goitre cases. The patients should be on follow-up for possible complications, especially hypothyroidism, for at least a year.

Risk Factors of Incidental Parathyroidectomy and its Relationship with Hypocalcemia after Thyroidectomy: A Retrospective Study

Background: The aim of this study was to determine the incidence of incidental parathyroidectomy, the relationship between incidental parathyroidectomy and postoperative hypocalcemia, and risk factors for incidental parathyroidectomy in patients undergoing thyroid surgery.

Methods: The study was conducted by analyzing the records of patients who underwent thyroid surgery in a tertiary university hospital between January 2012 and December 2017 retrospectively. The risk factors of postoperative hypocalcemia were determined by comparing postoperative Ca values with age, sex, preoperative Ca value, dominant nodule diameter, type of surgery, and histopathological examination of the thyroidectomy material. According to the final pathology results, the patients were divided into two groups - the ones with and without incidental parathyroidectomy. The risk factors for incidental parathyroidectomy were determined by comparing the two groups in terms of age, sex, dominant nodule diameter, type of surgery, and histopathological results (malign/benign).

Results: When the risk factors of postoperative hypocalcemia were examined, female gender, age <28.5 years old, low level of preoperative mean Ca value, and total thyroidectomy were found to be critical risk factors (p<0.05). When the risk factors of incidental parathyroidectomy were examined, total thyroidectomy and thyroid malignancy were found to be important risk factors (p<0.05).

Conclusion: Female gender, age<28.5 years old, low level of preoperative Ca value, and total thyroidectomy were associated with postoperative hypocalcemia, but no relationship was found between incidental parathyroidectomy and postoperative hypocalcemia.

Postoperative hypocalcemia: analysis of factors influencing early hypocalcemia development following thyroid surgery

BACKGROUND

Early Hypocalcemia is the most frequent complication after thyroid surgery. Several studies have tried to identify factors (patient caracteristics or surgical technique variations) affecting hypocalcemia following thyroid surgery. This studiy evaluates the role of several factors in postoperative hypocalcemia development.

METHODS

A retrospective study conducted on 2108 patients that underwent thyroid surgery in a single center (1669 women and 439 men). Postoperative early hypocalcemia was defined as serum calcium levels lower than 8,0 mg/dl measured 24 h after surgery. Following factors were evaluated in the study: sex, age, glandular hyperfunction, preoperative diagnosis, preoperative serum calcium levels, preoperative serum PTH levels, type of surgery performed (total thyroidectomy vs. lobectomy); minimally invasive video assisted thyroidectomy (MIVAT); number of parathyroid preserved in situ, postoperative serum calcium levels, changes in perioperative calcium levels (difference between preoperative values ​​and postoperative calcium levels), presence of carcinoma in the surgical specimen, presence of thyroiditis based on histopatology reports.

RESULTS

Among evaluated factors only gender and surgical procedure revealed to be significantly correlated to early hypocalcemia development. In fact female patients experienced postoperative hypocalcemia in 42% (701/1669) of cases, which was signicantly higher than the 21.4% (94/439) identified in men. We also noticed a greater hypocalcemia incidence in patient undergoing total thyroidectomy (38.8%) than in patient undergoing lobectomy group (13.8%). Early hypocalcemia development didn't appear to be related to preoperative serum calcium levels but it showed a statistically significant correlation with perioperative serum calcium level drop.

CONCLUSION

This findings suggest that sex (female gender is a strong risk factor),surgical procedure and perioperative changes in serum calcium are the only factors (among all variables examined) that influence early hypocalcemia development.

Risk factors and outcomes of incidental parathyroidectomy in thyroidectomy: A systematic review and meta-analysis

Introduction

Postoperative hypocalcemia is the most common complication of thyroidectomy. Incidental parathyroidectomy (IP) was thought to be associated with postoperative hypocalcemia. However, according to previous studies, the risk factors and clinical outcomes of IP remain controversial.

Methods

Eligible studies were searched in databases including PubMed, Web of Science, and EMBASE from January 1990 to September 2017. Articles focusing on the relationship between IP and postoperative hypocalcemia were included. The risk of publication bias was assessed using Begg’s test and Egger’s regression asymmetry test. Pooled analysis was performed to evaluate the effect of IP on postoperative hypocalcemia and related risk factors. Sensitivity analysis was also conducted to test the stability of our results. The effects of hypocalcemia type, permanent definition, IP incidence, total thyroidectomy, and malignancy operation were also examined using a further subgroup analysis.

Results

Thirty-five studies were finally included in the analysis after an exhaustive literature review. Pathology data demonstrate that incidental parathyroidectomy occurred in various locations: intrathyroidal (2.2–50.0%), intracapsular (16.7–40.0%) and extracapsular (15.7–81.1%) regions. Overall, the analysis found that malignancy (RR = 1.60, 95% CI: 1.27 to 2.02; p< 0.0001), central neck dissection (RR = 2.35, 95% CI: 1.47 to 3.75; p = 0.0004), total thyroidectomy (RR = 1.42, 95% CI: 1.20 to 1.67; p< 0.0001) and reoperation (RR = 1.81, 95% CI: 1.20 to 2.75; p = 0.005) were significant risk factors of IP in thyroid surgery. There was an obvious effect of IP on temporary/permanent (RR = 1.59, 95% CI: 1.37 to 1.84; p< 0.0001) and permanent (RD = 0.0220, 95% CI: 0.0069 to 0.0370; p = 0.0042) postoperative hypocalcemia. Sensitivity analysis showed that these results were robust. The subgroup analysis found that IP played a significant role in both biochemical and clinical hypocalcemia in thyroidectomy (p < 0.0001 and p = 0.0003, separately). The association of IP and permanent hypocalcemia using different definitions (6 months or more than 12 months) was also confirmed by the analysis. IP increased the incidence of temporary/permanent and permanent hypocalcemia for cases undergoing total thyroidectomy (40.4% vs 24.8% and 5.8% vs 1.4%, respectively). Thyroidectomy with IP was associated with more permanent hypocalcemia (RR = 3.10, 95% CI: 2.01 to 4.78; p< 0.0001) in malignant cases but was not associated with temporary/permanent hypocalcemia.

Conclusions

Malignancy, central neck dissection, total thyroidectomy and reoperation were found to be significant risk factors of IP. IP increases the risk of postoperative hypocalcemia after thyroidectomy. We recommend a more meticulous intraoperative identification of parathyroid gland in thyroidectomy to reduce IP, particularly for total thyroidectomy and malignancy cases.

Effect of nerve monitoring on complications of thyroid surgery

OBJECTIVE:

The most frequent and critical complications of thyroid surgery are recurrent laryngeal nerve palsy and hypocalcemia. In first years of the 21st century, intraoperative neuromonitoring (IONM) was introduced as a new technique to avoid the recurrent laryngeal nerve (RLN) injury. However, the role and the benefits of IONM are still controversial. In this study, we aimed to compare the postoperative complication rates during thyroid surgery with IONM usage (Group 1) and conventional direct visual technique without IONM usage (Group 2).

METHODS:

We conducted retrospective review of all patients undergoing thyroid surgery in Lütfiye Nuri Burat State Hospital General Surgery Department between 2014 and 2016 years. Patients have been classified in to two groups: Group 1 and 2.

RESULTS:

Overall, 191 patients were included in the study; Group 1 comprised 79 patients and Group 2 comprised 112 patients. Unilateral RLN paralysis was observed in 7 patients in Group 1 (8.9%) and 15 patients in Group 2 (13.4%) without any significant difference between the groups (p=0.368). Hypocalcemia was encountered in 5 patients (6.3%) in Group 1 and 18 patients (16.1%) in Group 2; this difference was statistically significant (p=0.045). Other complications (such as hematoma and suture reaction) were not significantly different. Operation time was found to be significantly shorter in Group 1 (Mean time, 93.08 min) than in Group 2 (116.54 min) (p=0.03).

CONCLUSION:

Proven effect of IONM on RLN paralysis is still controversial. However, easy identification of RLN, which gives more confidence to surgeon, and shorter operation time may be factors to lower hypocalcemia rates.

INCIDENTAL PARATHYROIDECTOMY DURING THYROID SURGERY - RISK, PREVENTION AND CONTROVERSIES; AN EVIDENCE-BASED REVIEW

Background

Postoperative hypocalcemia after thyroid surgery has a high prevalence ( 16-55% in different series). Incidental parathyroidectomy (IP) is a less discussed complication of thyroidectomy with consequences not properly defined. The aim of our study was to find incidence, risk factors and how to prevent IP.

Methods

Extensive search of English literature publications via PubMed was performed and 73 papers from 1980 to 2017 were analysed using the GRADE system/classification, quality of evidence was classified as "strong" when the result is highly unlikely to change existing recommendation and "weak" when opposite.

Results

Incidence of IP is 3.7-24.9%, while prevalence of permanent hypoparathyroidism is less frequent 6-12%. Direct relation between IP and hypoparathyroidism/hypocalcemia remains controversial. Female patients, ectopic parathyroids, small thyroids, Graves', malignancy, redo surgeries and total thyroidectomy favour IP. Routine visualization of parathyroids, new hemostatic devices, magnifying instruments and fluorescence can prevent incidental removal of parathyroids. Incidence of IP during videoassisted or robotic thyroidectomies was similar to open procedures. High volume, experienced and younger surgeons have lower complication rates (including hypoparathyroidism).

Conclusions

Incidental parathyroidectomy is more frequent than we might have expected. It should be avoided and parathyroid glands should be kept in situ. Majority of studies are retrospective (low degree of evidence according to previous mentioned GRADE classification) and further meta-analysis or randomized control studies are welcome in order to define the impact of incidental removal of parathyroids on postoperative outcome.