Incidental Parathyroidectomy during Total Thyroidectomy: Risk Factors and Consequences

Clinical significance and risk factors of incidental parathyroidectomy after total thyroidectomy

PURPOSE

Postoperative hypoparathyroidism is the most common complication after total thyroidectomy(TT). The clinical significance of incidental parathyroid glands(IP) detected in pathological examination of removed surgical material is still controversial. The aim of this study was to evaluate the clinical follow-up findings and risk factors of patients with IP.

METHODS

Postoperative pathology results and postoperative biochemical findings of patients who underwent TT±Central Neck Dissection(CND)/Lateral Neck Dissection(LND) between September,2020 and September,2023 in single institution were retrospectively evaluated. Patients with IP were divided into Group-1, and patients without IP were divided into Group-2. Patients of Group-1 were divided as Single IP and Double IP subgroups according to the number of IP.

RESULTS

The findings of a total of 412 patients were evaluated. IP was detected in 90(21.8%) of the patients. Postoperative hypoparathyroidism was more common in Group-1 at the 6th hour, 24th hour and 1st month postoperatively (69.7% vs. 31.7%, p < 0.0001; 61.1% vs. 27.7%, p < 0.0001, 26.2% vs. 12.2%, p = 0.002, respectively). Persistent hypoparathyroidism was observed at a rate of 5.3% in Group-2 and 11.5% in Group-1 (p = 0.041). Postoperative hypocalcemia was seen more frequently in Group-1 than in Group-2 at the 12th hour (34.4% vs. 23.2%, p = 0.031, respectively). There was no difference between Single IP vs. Double IP groups for the serum levels of Calcium and PTH. Among the risk factors evaluated for the detection of IP, in the univariance analysis, operation indications(p = 0.018), CND(p < 0.0001), surgeon experience(p = 0.016), thyroid gland volume(p = 0.02), preoperative serum TSH value(p = 0.031); in multivariance analysis, operation type ( ± CND) (OR:2.785; 95% CI: 1.175-6.605; p = 0.020) and operator experience between 10-20 years (OR: 0.117, 95% CI: 0.033-0.418, p = 0.001) and >20 years (OR: 0.254, 95%CI: 0.085-0.760, p = 0.014) were found significant compared to operators experienced <5 years.

CONCLUSION

Patients with detected IP after total thyroidectomy have lower postoperative Calcium and PTH. Significant risk factors for the IP were low level of surgeon experience and undergoing CND.

Incidental parathyroidectomy after thyroid surgery and relationship with postoperative hypocalcemia: a single tertiary center analysis

Incidental parathyroidectomy (IP) is a complication seen at varying rates after thyroid surgery, and its relationship with postoperative hypocalcemia has not been clarified. In this study, our goal was to identify the frequency and risk factors for IP in a large patient cohort and assess its correlation with postoperative hypocalcemia. A total of 4052 patients who underwent thyroid surgery between 2008 and 2020 were reviewed retrospectively. The patients were divided into two groups, the IP and non-IP groups, and compared in terms of demographics, surgical procedures, pathological diagnosis, and specimen weight. The relationships between IP and hypocalcemia were also evaluated. There were 587 (14.5%) IPs out of 4052 cases. In these patients, mostly one gland was removed (84.6%), and 23.2% of these glands were intrathyroidal. The rate of transient hypocalcemia was 39.9%, and that of permanent hypocalcemia was 1.7%. Female gender, malignancy, lower preoperative thyroid volume, presence of central lymph node dissection, lower specimen weight, presence of autotransplantation and capsule invasion in malignant cases were determined to be risk factors for IP. After excluding hemithyroidectomy and autotransplantation, transient and permanent hypocalcemia were found to be significantly higher in cases with IP (p < 0.001). Multivariate analysis showed that female sex, no multinodular goiter, central dissection, and low thyroid volume were risk-adjusted independent variables. Our findings highlight the significant role of IP in postoperative hypocalcemia. Given that most IPs are located in the perithyroidal region, precise surgical dissection is vital to preserve parathyroid gland function and prevent IP and subsequent hypocalcemia.

Risk Factors for Transient Hypoparathyroidism after Total Thyroidectomy: Insights from a Cohort Analysis

Background: Transient hypoparathyroidism (TH) is the main post-thyroidectomy complication, significantly impacting surgical outcomes, hospitalization length, and perceived perceived quality of life understood as mental and physical well-being. This study aims to identify possible associated risk factors. Methods: We analyzed 238 thyroidectomies (2020-2022), excluding instances of partial surgery, primary hyperparathyroidism, neck irradiation history, and renal failure. The variables considered were as follows: demographics, histology, autoimmunity, thyroid function, pre- and postoperative Vitamin D levels (where available), type of surgery, number of incidentally removed parathyroid glands (IRP), and surgeons' experience (>1000 thyroidectomies, <500, in training). Univariate analysis applied: χ2, Fisher's exact test for categorical variables, and Student's t-test for continuous variables. Subsequently, logistic multivariate analysis with stepwise selection was performed. Results: Univariate analysis did not yield statistically significant results for the considered variables. The 'No Complications' group displayed a mean age of 55 years, whereas the TH group showed a mean age of 51 (p-value = 0.055). We considered this result to be marginally significant. Subsequently, we constructed a multivariate logistic model. This model (AIC = 245.02) indicated that the absence of incidental parathyroidectomy was associated with the age class >55 years, presenting an odds ratio (OR) of 9.015 (p-value < 0.05). Simultaneously, the age class >55 years exhibited protective effects against TH, demonstrating an OR of 0.085 (p-value < 0.01). Similarly, the absence of incidental parathyroidectomy was found to be protective against TH, with an OR of 0.208 (p-value < 0.01). Conclusions: Multivariate analysis highlighted that having "No IRP" was protective against TH, while younger age was a risk factor. Surgeon experience does not seem to correlate with IRP or outcomes, assuming there is adequate tutoring and a case volume close to 500 to ensure good results. The effect of reimplantation has not been evident in transient hypoparathyroidism.

Factors affecting the rates of incidental parathyroidectomy during thyroidectomy

BACKGROUND

The most important factors affecting the development of postoperative hypocalcaemia (PH) include intraoperative trauma to the parathyroid glands, incidental parathyroidectomy (IP), and the surgeon's experience. In this study, we aimed to determine the incidence of IP, evaluate its effect on postoperative calcium levels and investigate the effect of surgeon experience and volume on IP incidence and postoperative calcium levels.

METHODS

This retrospective study included 645 patients who underwent thyroid surgery at the Department of General Surgery, Kütahya Health Sciences University between September 2016 and March 2020. All patients underwent surgery at a single clinic by general surgeons experienced in thyroid surgery and their residents (3-5 years).

RESULTS

Normal parathyroid glands were reported in 58 (8.9%) of 645 patients. In 5 (8.6%) of 58 patients the parathyroid gland was detected in the intrathyroidal region. PH developed in ten patients (17.2%) with incidental removal of the parathyroid glands. A statistically significant difference was found between the number of incidentally removed parathyroid glands and the development of hypocalcaemia (p<0.05). Normal parathyroid glands were reported in the pathology of 37 (7.9%) patients operated on by general surgeons and 22 (12.6%) patients operated on by their residents. PH developed in 39 (8.2%) patients operated on by general surgeons and in 8 (4.5%) patients operated on by their residents.

CONCLUSIONS

We found that the complication rate during the resident training process was the same as that of experienced general surgeons. A thyroidectomy can be safely performed by senior residents during residential training.

Accidental parathyroidectomy during total thyroidectomy and hypoparathyroidism in a large series of 766 patients: incidence and consequences in a referral center

PURPOSE

Transient hypoparathyroidism is the most common complication after total thyroidectomy, and accidental parathyroidectomy (AP) may be a cause. The aim of this study was to investigate the incidence of AP and its impact on postoperative calcemia.

MATERIALS AND METHODS

From February 2016 to May 2018, 766 patients undergoing total thyroidectomy were prospectively included. Surgical indications, hormonal status, definitive histology, and postoperative calcium and PTH levels were analyzed.

RESULTS

578/(75.45%) were women and 188/(24.55%) men with mean age of 53.4 years. Parathyroid tissue on the thyroid specimen was observed in 40 (5.2%) patients: 30 APs and 10 parathyroid fragments. Among the 30 APs, 12 glands were intrathyroid and 18 (2.3%) in eutopic location. 97 (12.6%) patients were treated for postoperative hypocalcemia: 90 (11.7%) had transient and 5 (0.6%) definitive hypoparathyroidism; 2 were lost in follow-up. 13/30 (43.3%) with AP had transient hypoparathyroidism. A strong correlation was found (p < 0.0001) between AP and postoperative hypocalcemia. 1/30 (3.3%) patient with APs had definitive hypoparathyroidism. Transient and persistent nerve palsies were found in 10 (1.3%) and 3 (0.4%) patients, respectively.

DISCUSSION

A careful examination of the thyroid gland after resection help to identify an AP that could be autotransplanted. Surgeon and hospital activity volume per years seem to reduce the risk of hypoparathyroidism.

CONCLUSION

Total thyroidectomy and intrathyroid localization of parathyroid glands are risk factors for the AP. The incidence of AP was 2.3%, and this remains low due to our longstanding experience in thyroid and parathyroid surgery.

Intraoperative Identification of Thyroid and Parathyroid Tissues During Human Endocrine Surgery Using the MasSpec Pen

Importance

Intraoperative identification of tissues through gross inspection during thyroid and parathyroid surgery is challenging yet essential for preserving healthy tissue and improving outcomes for patients.

Objective

To evaluate the performance and clinical applicability of the MasSpec Pen (MSPen) technology for discriminating thyroid, parathyroid, and lymph node tissues intraoperatively.

Design, Setting, and Participants

In this diagnostic/prognostic study, the MSPen was used to analyze 184 fresh-frozen thyroid, parathyroid, and lymph node tissues in the laboratory and translated to the operating room to enable in vivo and ex vivo tissue analysis by endocrine surgeons in 102 patients undergoing thyroidectomy and parathyroidectomy procedures. This diagnostic study was conducted between August 2017 and March 2020. Fresh-frozen tissues were analyzed in a laboratory. Clinical analyses occurred in an operating room at an academic medical center. Of the analyses performed on 184 fresh-frozen tissues, 131 were included based on sufficient signal and postanalysis pathologic diagnosis. From clinical tests, 102 patients undergoing surgery were included. A total of 1015 intraoperative analyses were performed, with 269 analyses subject to statistical classification. Statistical classifiers for discriminating thyroid, parathyroid, and lymph node tissues were generated using training sets comprising both laboratory and intraoperative data and evaluated on an independent test set of intraoperative data. Data were analyzed from July to December 2022.

Main Outcomes and Measures

Accuracy for each tissue type was measured for classification models discriminating thyroid, parathyroid, and lymph node tissues using MSPen data compared to gross analysis and final pathology results.

Results

Of the 102 patients in the intraoperative study, 80 were female (78%) and the median (IQR) age was 52 (42-66) years. For discriminating thyroid and parathyroid tissues, an overall accuracy, defined as agreement with pathology, of 92.4% (95% CI, 87.7-95.4) was achieved using MSPen data, with 82.6% (95% CI, 76.5-87.4) accuracy achieved for the independent test set. For distinguishing thyroid from lymph node and parathyroid from lymph node, overall training set accuracies of 97.5% (95% CI, 92.8-99.1) and 96.1% (95% CI, 91.2-98.3), respectively, were achieved.

Conclusions and Relevance

In this study, the MSPen showed high performance for discriminating thyroid, parathyroid, and lymph node tissues intraoperatively, suggesting this technology may be useful for providing near real-time feedback on tissue type to aid in surgical decision-making.

Converting a probe-based fluorescence system into an easy-to-use adjunct for the detection of parathyroid glands accidentally resected intraoperatively

PURPOSE

The reported threshold of a near-infrared fluorescence detection probe (FDP) for judging parathyroid glands (PGs) is based on the autofluorescence intensity relative to other non-PG tissues, making it unreliable when not enough reference tissues are measured. We aim to convert FDP into a more convenient tool for identifying accidentally resected PGs by quantitative measurements of autofluorescence in resected tissues.

METHODS

It was a prospective study approved by the Institutional Review Board. The research was divided into two stages: (1) In order to calibrate the novel FDP system, autofluorescence intensity of different in / ex vivo tissues was measured and the optimal threshold was obtained using receiver operating characteristic (ROC) curve. (2) To further validate the effectiveness of the new system, detection rates of incidental resected PGs by pathology in the control group and by FDP in the experimental group were compared.

RESULTS

Autofluorescence of PGs was significantly higher than that of non-PG tissue (43 patients, Mann-Whitney U test, p < 0.0001). An optimal threshold of sensitivity / specificity (78.8% and 85.1%) for discriminating PGs was obtained. The detection rates of experimental group (20 patients) and control group (33 patients) are 5.0% and 6.1% respectively (one-tailed Fisher's exact test, p = 0.6837), indicating the novel FDP system can achieve a similar proportion of PG detection compared with pathological examinations.

CONCLUSIONS

The novel FDP system can be used as an easy-to-use adjunct for detecting PG accidentally resected intraoperatively before the tissues are sent for frozen sections during thyroidectomy surgeries.

TRIAL REGISTRATION

Registration number: ChiCTR2200057957.

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.

Near-infrared autofluorescence of the parathyroid glands during thyroidectomy for the prevention of hypoparathyroidism: a prospective randomized clinical trial

Purpose

Postoperative hypoparathyroidism remains the most often complication in thyroid surgery. Near-infrared autofluorescence (NIR-AF) is a modality to identify parathyroid glands (PG) in vivo with high accuracy, but its use in daily routine surgery is unclear so far. In this randomized controlled trial, we evaluate the ability of NIR-AF to prevent postoperative hypoparathyroidism following total thyroidectomy.

Methods

Patients undergoing total thyroidectomy were allocated in two groups with the use of NIR-AF in the intervention group or according to standard practice in the control group. The aim was to identify the PGs in an early most stage of the operation to prevent their devascularization or removal. Parathyroid hormone was measured pre- and postoperatively and on postoperative day (POD) 1. Serum calcium was measured on POD 1 and 2. Possible symptoms and calcium/calcitriol supplement were recorded.

Results

A total of 60 patients were randomized, of whom 30 underwent NIR-AF-based PG identification. Hypoparathyroidism at skin closure occurred in 7 out of 30 patients using NIR-AF, respectively, in 14 out of 30 patients in the control group (p=0.058). There was no significant difference in serum calcium and parathyroid hormone levels between both groups. Likewise, NIR-AF could not detect PGs at a higher rate.

Conclusion

The use of NIR-AF may help surgeons identify and preserve PGs but did not significantly reduce the incidence of postoperative hypoparathyroidism in this trial. Larger case series have to clarify whether there is a benefit in routine thyroidectomy.

Trial registration number

DRKS00009242 (German Clinical Trial Register). Registration date: 03.09.2015

Rate of Incidental Parathyroidectomy in a Pediatric Population

Objective

Incidental parathyroidectomy is a relatively common occurrence in thyroid surgery, which may lead to hypoparathyroidism and postoperative hypocalcemia, but it is not well studied in children. The objectives of this study were to determine the rate of incidental parathyroidectomy, identify potential risk factors, and investigate postoperative complications in children undergoing thyroidectomy.

Study Design

Retrospective cohort study.

Setting

Patients who underwent thyroidectomy over a 10-year period at a tertiary children’s hospital.

Methods

Pathology reports were reviewed to determine incidental parathyroid gland tissue. Additional data collected included patient demographics, type of procedure, underlying thyroid pathology, as well as immediate and long-term postoperative clinical outcomes.

Results

Of 209 patients, 65 (31%) had incidental parathyroidectomy. Several variables were associated with incidental parathyroidectomy on univariable analysis. However, in the final multivariable model, only thyroidectomy with lymph node dissection was associated with increased odds of having incidental parathyroidectomy (odds ratio, 3.3; P = .04; 95% CI, 1.1-9.8). After a median follow up of 1 year, a significantly higher percentage of patients with incidental parathyroidectomy had evidence of long-term hypoparathyroidism (9/62 [15%] vs 3/144 [2%], P = .001).

Conclusion

Incidental parathyroidectomy was relatively common in our pediatric thyroidectomy population, which may be a result of several anatomic, clinical, and surgeon-related factors. Close attention to parathyroid preservation with meticulous surgical technique is the most practical method of preventing long-term hypoparathyroidism and hypocalcemia.

INCIDENTAL PARATHYROIDECTOMY DURING TOTAL THYROIDECTOMY AS A POSSIBLE RISK FACTOR OF HYPOCALCEMIA. EXPERIENCE OF A SINGLE CENTER AND REVIEW OF LITERATURE

CONTEXT

Post-operative clinical and biochemical hypocalcemia is a common complication of thyroid surgery and the correlation with incidental parathyroidectomy (IP) remains controversial.

OBJECTIVE

To evaluate the incidence of IP during TT, its correlation to early post-surgery hypocalcemia, and its potential risk factors.

PATIENTS AND METHODS

77 consecutive patients submitted to thyroid surgery between January 2018 and December 2019. Demographic, clinical, biochemical, surgical and histopathological factors were assessed. Statistical multivariate analysis was performed to identify the risk of IP.

RESULTS

IP was evident in 22 (28.5%) patients who underwent TT, TT with lymph node dissection of the central compartment (CLND) and reoperation for previous hemithyroidectomy with CLND. Early symptomatic hypocalcemia 24 hours after TT was demonstrated in 12/22 (54.5%) patients, with PTH value of <14pg/mL in 7/12 (58.3%) patients, and in 6 of these 7 patients (85.7%) the PTH value was <6.3pg/mL. In 5/22 (22.7%) patients the IP was associated with biochemical hypocalcemia <8.4mg/dL, and in 5/22 (22.7%) patients anatomical damage was not associated with a reduction in plasma calcium levels. The severity of early post-op hypocalcemia was not correlated with the number of parathyroid glands left in situ. The multivariate analysis did not show statistically significant values between the clinical-pathological variables and increased risk of IP.

CONCLUSIONS

No IP clinical-pathological risk factors have been identified during thyroid surgery. In all cases of TT, with or without CLND, the meticulous identification of the parathyroid glands, whose incidental removal is frequently associated with clinical and biochemical hypocalcemia, is recommended.

Colorectal cancer metastases to the thyroid gland-a systematic review : Colorectal cancer thyroid metastases

BACKGROUND

Despite its rich vasculature, the thyroid gland is a rare site of metastatic disease. We present a systematic review of colorectal cancer (CRC) thyroid metastases, with emphasis on diagnosis, therapeutic management, and oncological outcomes.

METHODS

A systematic review of the English literature (1990 to 2019) was performed, using the PubMed, Embase, and Google Scholar bibliographic databases. For each patient, epidemiological, surgical, histopathological, and oncological data were extracted.

RESULTS

A total of 111 patients (40% males, mean age 61 ± 12 years) were included in the final analysis. The primary CRC was locally advanced (T3-T4) in 83%, had positive lymph nodes (N+) in 65%, and had distant metastases (M+) in 28%. Thyroid metastases were synchronous in 15% and metachronous in 80%, with a mean interval of 51 ± 31 months from primary tumor treatment. Thyroid metastatic disease was diagnosed clinically (60%), radiologically (33%), biochemically (2%), or postmortem (5%). When performed, FNA biopsy was diagnostic in 73% and highly suspicious in 13%. A total of 63% of patients had additional distant metastases, usually in the liver or lungs, while 68% of patients underwent surgical excision (total or subtotal thyroidectomy 58%, lobectomy 42%) and 43% received adjuvant chemotherapy or radiotherapy. Mean overall survival after primary CRC was 55.5 ± 34.7 months, with mean disease-free survival of 31.3 ± 27.2 months. Following diagnosis or treatment of thyroid metastases, 1-, 2- and 3-year survival rates were 79, 66, and 60%, respectively. Mean survival following diagnosis of thyroid metastases was 11.3 months.

CONCLUSIONS

CRC thyroid metastasis is a relatively uncommon event, usually associated with locoregionally advanced tumors. Prognosis is poor, mainly due to multimetastatic disease.

Central neck dissection is an independent risk factor for incidental parathyroidectomy

OBJECTIVE

This study aims to determine the frequency of incidental parathyroidectomy (IP), to reveal the risk factors and to present the clinical importance of IP through the experiences of our clinic.

MATERIALS AND METHODS

Patients undergoing thyroid surgery between June 2016 and May 2019 were reviewed retrospectively. Along with demographic data, surgery reports, pathology results and postoperative follow-up data were examined. Factors assumed to be associated with IP and postoperative hypocalcemia were compared between the IP group and the non-IP group.

RESULTS

A total of 633 patients with a mean age of 48 ± 13 years were included in this study. IP was detected in 138 (21.8%) patients and parathyroid glands were localized 29.72% intrathyroidal. Postoperative hypocalcemia in the IP group was approximately 2-fold higher than the no-IP group (%15.94 to %7.27), (p < .001). Gender (p = .014), body mass index (p = .021), both preoperative and postoperative diagnosis of malignancy (p < .001) and performing central neck dissection (CND) (p < .001) were significantly associated with IP in univariate analysis. However, multivariate analysis demonstrated that CND was independently associated with IP (OR = 0.301, 95% Cl: 0.161-0.562, p < .001).

CONCLUSION

This study reveals that IP increases the frequency of postoperative temporary and permanent hypocalcemia in patients undergoing thyroid surgery, and CND is the only independent risk factor for IP. Highlights of the study This study reveals that central neck dissection is the most important and only independent risk factor for incidental parathyroidectomy in patients undergoing thyroid surgery. According to our analysis, both temporary and permanent hypocalcemia, which occurs in the postoperative period, are associated with incidental parathyroidectomy.

Impact of incidental parathyroidectomy and mediastinal-recurrent cellular and lymph-node dissection on parathyroid function after total thyroidectomy

OBJECTIVES

To determine the impact of incidental parathyroidectomy and mediastinal-recurrent cellular and lymph-node dissection on parathyroid function after total thyroidectomy.

MATERIAL AND METHODS

A single-center retrospective study was conducted for a 5-year period in a university hospital center, including 605 patients undergoing total thyroidectomy, 52 of whom had mediastinal-recurrent cellular and lymph-node dissection.

ENDPOINTS

The main endpoint was intraoperative number of parathyroid glands as predictor of parathyroid hormone (PTH) level and postoperative hypocalcemia. The secondary endpoint was the correlation between associated mediastinal-recurrent cellular and lymph-node dissection and incidental parathyroidectomy and its impact on PTH level and calcemia in the immediate postoperative period and at 1 month.

RESULTS

161 patients (26.61%) showed hypocalcemia in the immediate postoperative period and 12 (1.98%) at 1 month. Mediastinal-recurrent cellular and lymph-node dissection increased incidental parathyroidectomy risk 4.6-fold. Mediastinal-recurrent cellular and lymph-node dissection was associated with a statistically "suggestive" decrease in day-1 calcemia (P=0.03), and no significant decrease at 1 month (P=0.52). Incidental parathyroidectomy (6.7% of cases with parathyroidectomy versus 1.3% without) did not significantly increase the rate of early hypocalcemia (P=0.28), but was associated with a "suggestive" worsening at 1 month (P=0.02).

CONCLUSION

Hypocalcemia after total thyroidectomy is a complex, probably multifactorial issue. Systematic parathyroid gland identification is not recommended due to the increased risk of gland lesion, mainly by devascularization. Incidental parathyroidectomy may induce hypocalcemia at 1 month postoperatively (statistically "suggestive" association).

Risk Factors of Incidental Parathyroidecomy in Thyroid Surgery

Background: Incidental parathyroidectomy with subsequent hypoparathyroidism and postoperative hypocalcemia is thought to be one of the common complications of thyroidectomy. Current literature reports wide discrepancy in incidence and risk factors.

Objectives: The aim of our study was to evaluate the incidence and risk factors of incidental parathyroidectomy in thyroid surgery.

Methods: A retrospective study included 270 patients who had thyroid surgery that was performed over two years from January 2017 to December 2018 in two tertiary care hospitals. Preoperative and postoperative records were assessed. Factors such as gender, diagnosis, type of surgery, and usage of surgical loupes during the procedure were evaluated and were compared to find the association with incidental parathyroidectomy in thyroid surgery.

Results: Incidental parathyroidectomy was noticed in 62 (23%) surgical specimens during histopathologic examination. There was no significant association between incidental parathyroidectomy and sex of patient, use of surgical loupes, pathology of thyroid disease, or neck dissection.

Conclusion: Although the risk of incidental parathyroidectomy is inevitable, careful dissection and meticulous intraoperative identification of parathyroid gland during thyroidectomy can reduce the incidence of incidental parathyroidectomy, thereby minimizing the risk of postoperative hypoparathyroidism and hypocalcemia.

Factors contributing to unintentional parathyroidectomy during thyroid surgery

Unintentional parathyroidectomy during thyroid surgery has an incidence ranging between 1% and 31% across institutions. Many studies have identified malignancy and central neck dissection as risk factors for losing parathyroid glands, but few studies have evaluated the impact of other factors such as lymphocytic thyroiditis, hyperthyroidism, or concomitant primary hyperparathyroidism. The purpose of this study was to investigate which factors contribute to parathyroid loss during thyroid surgery. Charts of 269 patients undergoing thyroid surgery at a tertiary care medical center from 2010 to 2013 were retrospectively reviewed. Sixty-six patients (24.5%) experienced unintentional parathyroidectomy. Bivariate analysis showed no significant differences in patient characteristics. Patients with unintentional parathyroid removal had a significantly smaller largest thyroid nodule size (P = 0.002), higher rate of central neck dissection (30.3% vs 7.9%, P < 0.0001), and higher rate of malignancy (50% vs 36.0%, P = 0.04). Multivariable analysis showed that the strongest risk factor for unintentional parathyroidectomy was central neck dissection (P = 0.0008; odds ratio 4.72, confidence interval 1.91-11.71). In conclusion, central neck dissection for thyroid malignancy is the strongest risk factor for unintentional thyroidectomy. The presence of concomitant primary hyperparathyroidism, lymphocytic thyroiditis, or hyperthyroidism did not appear to increase the risk of unintentional parathyroidectomy.

Predicting transient hypocalcemia in patients with unplanned parathyroidectomy after thyroidectomy

OBJECTIVE

To assess the utility of rapid parathyroid hormone (PTH) values in predicting transient post-operative hypocalcemia in patients with unplanned parathyroidectomy during total or completion thyroidectomy.

METHODS

All patients who underwent total or completion thyroidectomy between January 2010 and January 2015 were reviewed. Incidences of post-operative hypocalcemia were compared in patients with and without unplanned parathyroidectomy. Unplanned parathyroidectomy was defined as intra-operative incidental or intentional parathyroidectomy. Logistic regression assessed for predictors of hypocalcemia and optimum amount of calcium supplementation.

RESULTS

Thirty-eight (13.6%) patients had evidence of incidental parathyroidectomy and 39/280 (13.9%) patients had parathyroid autotransplantation intra-operatively. Central neck dissection and malignancy were identified as risk factors for unplanned parathyroidectomy (p = 0.001, p = 0.060). Patients with unplanned parathyroidectomy were more likely to have hypocalcemia (p = 0.002) and hypoparathyroidism (p < 0.0005). PTH value was the only significant predictor of hypocalcemia in these patients. In patients with a post-operative PTH of ≤15, initial calcium supplementation ≥ 1000 mg decreased the risk of hypocalcemia (p < 0.05).

CONCLUSION

Post-operative PTH value predicts hypocalcemia in patients undergoing total and completion thyroidectomy with unplanned parathyroidectomy. In patients with a post-operative PTH < 15, initial calcium supplementation with ≥1000 mg of elemental calcium is recommended.

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.

Clinical course of incidental parathyroidectomy: Single center experience

OBJECTIVE

Thyroidectomy is a very common surgical procedure. Regardless of surgeon experience, incidental parathyroidectomy is a complication of thyroidectomy. The aim of this study was to identify the clinical course of incidental parathyroidectomies after thyroidectomy.

METHODS

Patients who underwent thyroidectomy between January 2010 and June 2014 were evaluated retrospectively. Pathology reports were reviewed for the presence of parathyroid tissue in the thyroidectomy pathology specimens. Information regarding demographic, laboratory variables, operative details, and postoperative complications were collected.

RESULTS

Incidental parathyroidectomy was found in 178 out of 3022 patients who had thyroidectomy (5.8%). Types of surgeries performed for 178 patients were total thyroidectomy (TT) in 132(74.2%) cases, TT and central lymph node dissection(CLND) in 30 (16.9%) cases, lobectomy in seven cases (3.9%), completion thyroidectomy in five (2.8%) patients and modified cervical lymph node dissection in four (2.2%)patients. One and two parathyroid glands were accidentally removed in 152 (85.3%) and 26 (14.7%) patients, respectively. In the entire series, biochemical temporary postoperative hypocalcemia occurred in 75(42.1%) patients and permanent hypocalcemia occured in 12 (6.7%) patients with incidental parathyroidectomy. There was not a statistically significant difference regarding the occurrence of postoperative permanent hypocalcemia between the patients who had incidental parathyroidectomy of one gland and the patients with two incidental parathyroidectomies (p=0.114).

CONCLUSION

Incidental parathyroidectomy is not uncommon during thyroidectomy. No association between inadvertent parathyroidectomy and postoperative permanent hypocalcemia was found.

Incidence, prevalence and risk factors for post-surgical hypocalcaemia and hypoparathyroidism

Hypocalcaemia following thyroid surgery is common and is associated with significant short and long term morbidity. Damage to or devascularisation of parathyroid glands is the predominant underlying mechanism; although other factors such as hungry bone syndrome may occasionally contribute to it in the immediate post-operative period. The reported incidence of post-surgical hypocalcaemia and/or hypoparathyroidism (PoSH) varies significantly in the literature; the variation thought to be at least partly due to differences in the definitions used. Figures on the prevalence of chronic or long term post-surgical hypocalcaemia in the population are unclear. Risk factors for PoSH have been extensively studied in recent years and may be classified into patient, disease and surgery related factors. Some risk factors are modifiable; but both modifiable and non-modifiable factors help in generating a risk profile that may be used to select patients for preventative measures and/or changes in surgical strategy. This narrative review discusses recent literature on the incidence, prevalence and risk factors for PoSH.

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.