Risk factors of incidental parathyroidectomy after thyroidectomy for benign thyroid disorders

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 and Protective Factors of Postoperative and Persistent Hypoparathyroidism after Total Thyroidectomy in a Series of 1965 Patients

BACKGROUND

Postoperative hypoparathyroidism (HypoPTH) is the most common complication following total thyroidectomy. Several risk factors have been identified, but data on postoperative follow-up are scarce.

METHODS

The study focused on 1965 patients undergoing surgery for benign and malignant thyroid diseases at a tertiary-level academic center. Anamnestic, biochemical, surgical, pathological, and follow-up data were evaluated. HypoPTH was defined by a serum concentration of PTH < 10 pg/mL on the first or the second post-operative day. Persistent HypoPTH was defined by the need for calcium/active vitamin D treatment > 12 months after surgery.

RESULTS

Postoperative HypoPTH occurred in 542 patients. Multivariate analysis identified the association of central lymph-nodal dissection, reduced preoperative PTH levels, a lower rate of parathyroid glands preserved in situ, and longer duration of surgery as independent risk factors. At a median follow-up of 47 months, HypoPTH regressed in 443 patients (more than 6 months after surgery in 7%) and persisted in 53 patients. Patients receiving a lower dose of calcium/active vitamin D treatment at discharge (HR 0.559; p < 0.001) or undergoing prolonged, tailored, and direct follow-up by the operating endocrine surgeon team had a significantly lower risk of persistent HypoPTH (2.4% compared to 32.8% for other specialists) (HR 2.563; p < 0.001).

CONCLUSIONS

Various patient, disease, and surgeon-related risk factors may predict postoperative HypoPTH. Lower postoperative calcium/active vitamin D treatment and prolonged, tailored follow-up directly performed by operating endocrine surgeons may significantly reduce the rate of persistent HypoPTH.

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.

Incidental parathyroidectomy during total thyroidectomy and functional parathyroid preservation: a retrospective cohort study

BACKGROUND

The published rate of incidental parathyroidectomy (IP) during thyroid surgery varies between 5.8% and 29%. The risk factors and clinical significance of postoperative transient hypocalcemia and permanent hypoparathyroidism are still debated. The aims of this study were to assess the clinical relevance of avoidable IP for transient hypocalcemia and permanent hypoparathyroidism, and to describe the risk factors for IP.

METHODS

This retrospective cohort study included 1,537 patients who had a one-step total thyroidectomy in a high-volume endocrine surgery center between 2018 and 2019. Pathology reports were reviewed for incidentally removed parathyroid glands. Intrathyroidal parathyroid glands were excluded from the study. Demographic characteristics, potential risk factors, and postoperative calcium and PTH levels were compared between IP and control groups.

RESULTS

Avoidable IP occurred in 234 (15.2%) patients. Patients with IP had a higher risk of transient hypocalcemia (17.9% vs. 11.5%, p = 0.006; odds ratio [OR] 1.68, 95% confidence interval [95% CI]1.16-2.45) and permanent hypoparathyroidism (4.7% vs. 1.6%, p = 0.002; OR 3.01, 95% CI 1.29-6.63) than patients without IP. Multivariate analysis showed that central lymph node dissection (CLND) and incidental removal of thymus tissue were independent risk factors for IP (OR 4.83, 95% CI 2.71-8.86, p < 0.001 and OR 1.72, 95% CI 1.02-2.82, p = 0.038).

CONCLUSIONS

Patients with IP were more likely to develop transient hypocalcemia and permanent hypoparathyroidism, indicating the clinical significance of avoidable IP for patients and the need for raising awareness among surgeons. Patients undergoing CLND are at a higher risk for IP, and should be adequately informed and treated. Any removal of thymus tissue should be avoided during CLND.

Autofluorescence detection and co-axial projection for intraoperative localization of parathyroid gland

Background

Near-infrared (NIR) autofluorescence detection is an effective method for identifying parathyroid glands (PGs) in thyroidectomy or parathyroidectomy. Fiber optical probes provide quantitative autofluorescence measurements for PG detection owing to its high sensitivity and high excitation light cut-off efficiency at a fixed detection distance. However, an optical fiber probe lacks the imaging capability and cannot map the autofluorescence distribution on top of normal tissue background. Therefore, there is a need for intraoperative mapping of PGs with high sensitivity and imaging resolution.

Methods

We have developed a fluorescence scanning and projection (FSP) system that combines a scanning probe and a co-axial projector for intraoperative localization and in situ display of PGs. Some of the key performance characteristics, including spatial resolution and sensitivity for detection, spatial resolution for imaging, dynamic time latency, and PG localization capability, are characterized and verified by benchtop experiments. Clinical utility of the system is simulated by a fluorescence-guided PG localization surgery on a tissue-simulating phantom and validated in an ex vivo experiment.

Results

The system is able to detect indocyanine green (ICG) solution of 5 pM at a high signal-to-noise ratio (SNR). Additionally, it has a maximal projection error of 0.92 mm, an averaged projection error of 0.5 ± 0.23 mm, and an imaging resolution of 748 μm at a working distance ranging from 35 to 55 cm. The dynamic testing yields a short latency of 153 ± 54 ms, allowing for intraoperative scanning on target tissue during a surgical intervention. The simulated fluorescence-guided PG localization surgery has validated the system’s capability to locate PG phantom with operating room ambient light interference. The simulation experiment on the PG phantom yields a position detection bias of 0.36 ± 0.17 mm, and an area intersection over unit (IoU) of 76.6% ± 6.4%. Fluorescence intensity attenuates exponentially with the thickness of covered tissue over the PG phantom, indicating the need to remove surrounding tissue in order to reveal the weak autofluorescence signal from PGs. The ex vivo experiment demonstrates the technical feasibility of the FSP system for intraoperative PG localization with accuracy.

Conclusion

We have developed a novel probe-based imaging and navigation system with high sensitivity for fluorescence detection, capability for fluorescence image reconstruction, multimodal image fusion and in situ PG display function. Our studies have demonstrated its clinical potential for intraoperative localization and in situ display of PGs in thyroidectomy or parathyroidectomy.

Primary study of identification of parathyroid gland based on laser-induced breakdown spectroscopy

The identification and preservation of parathyroid glands (PGs) is a major issue in thyroidectomy. The PG is particularly difficult to distinguish from the surrounding tissues. Accidental damage or removal of the PG may result in temporary or permanent postoperative hypoparathyroidism and hypocalcemia. In this study, a novel method for identification of the PG was proposed based on laser-induced breakdown spectroscopy (LIBS) for the first time. LIBS spectra were collected from the smear samples of PG and non-parathyroid gland (NPG) tissues (thyroid and neck lymph node) of rabbits. The emission lines (related to K, Na, Ca, N, O, CN, C₂, etc.) observed in LIBS spectra were ranked and selected based on the important weight calculated by random forest (RF). Three machine learning algorithms were used as classifiers to distinguish PGs from NPGs. The artificial neural network classifier provided the best classification performance. The results demonstrated that LIBS can be adopted to discriminate between smear samples of PG and NPG, and it has a potential in intra-operative identification of PGs.

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.

Short-Term Outcomes of Surgery for Graves' Disease in Germany

BACKGROUND

Surgical treatment of Graves' disease (GD) has a potentially increased incidence of postoperative hypoparathyroidism, recurrent laryngeal nerve palsy (RLNP) and bleeding. The aim of this study was to evaluate the current extent of surgery for the treatment of GD and its safety as a short-term outcome.

METHODS

Patients who underwent thyroid resection for GD were identified from the prospective StuDoQ/Thyroid registry. Patient data were retrospectively analyzed regarding demographics, surgical procedures and perioperative outcomes. Statistics were performed with Student's t-test or Fisher's exact test and multivariate Cox regression analysis. The level of statistical significance was set at p < 0.05.

RESULTS

A total of 1808 patients with GD with a median age of 44 (range 14-85) years were enrolled in a 25-month period by 78 departments, of which 35.7% (n = 645) had an endocrine orbitopathy and 0.1% (n = 6) had thyrotoxic crisis. Conventional open surgery was used in 98.6% of cases and minimally invasive or remote-access approaches were used in 1.4%. Total thyroidectomy was performed in 93.4% of cases (n = 1688). Intraoperative neuromonitoring (IONM) was used in 98.9% (n = 1789) of procedures. In 98.3% (n = 1777) at least one parathyroid gland was visualized and in 20.7% (n = 375) parathyroids were autografted. The rates of unilateral and bilateral transient RLNP were 3.9% (n = 134/3429 nerves at risk) and 0.1% (n = 4/3429 NAR). The rates of transient RLNP tended to be higher when intermittent IONM was used compared to continuous IONM (4.1% vs. 3.4%, p < 0.059). The rate of transient postoperative hypoparathyroidism was overall 29% (n = 525/1808). Multivariate analysis revealed fewer than 300 thyroid resections and fewer than 15 thyroid resections for GD per year, male sex, BMI > 30, autotransplantation of parathyroid glands and previous bilateral thyroid surgery as independent risk factors for postoperative temporary hypoparathyroidism. Reoperations for bleeding (1.3%) were rare.

CONCLUSION

Total thyroidectomy with IONM is safe and currently the most common surgical therapy for GD in Germany. Postoperative hypoparathyroidism is the major complication which should be focused on.

Near-Infrared Fluorescence Imaging in the Identification of Parathyroid Glands in Thyroidectomy

OBJECTIVES/HYPOTHESIS

To assess the ability of near-infrared fluorescence imaging (NIFI) to identify parathyroid glands (PGs) among histologically proven PG/non-PG specimens compared with a surgeon's visual acumen, and to determine NIFI sensitivity in detecting incidentally resected PGs from thyroidectomy specimens, compared to the surgeon's visual inspection.

STUDY DESIGN

Prospective study.

METHODS

With mean age of 61 years, 36 patients with various thyroid diseases were enrolled. Possible PGs (n = 28) and lymph nodes (n = 32) were identified by the experienced surgeon's visual inspection. Using NIFI, 15 PGs were further identified from thyroidectomy specimens. For these 75 specimens, the surgeon's judgments (PG vs. non-PG) were recorded. Histological evaluation was performed after examining the NIFI auto-fluorescence of each specimen.

RESULTS

There were no significant differences in sensitivity, specificity, positive predictive value, and negative predictive value between the surgeon's visual inspection and NIFI in identifying PGs, with values of 100%/97.1%, 85.0%/87.5%, 85.4%/87.2%, and 100%/97.2%, respectively. The sensitivity of NIFI (82.9%) for detection of PGs from thyroidectomy specimens was significantly higher than that of the surgeon's visual inspection (61.0%). False negative specimens contained bleeding/congestion and/or encapsulation by thick tissues, whereas false positive specimens contained electrocoagulated tissues.

CONCLUSIONS

NIFI showed results comparable to the experienced surgeon's visual inspection in identifying PGs. This could benefit novice surgeons. NIFI may be useful for experienced surgeons to locate incidentally resected PGs within thyroidectomy specimens for auto-transplantation. Prevention of intra-gland bleeding and congestion, careful removal of thick capsules, and bloodless surgeries without electrocoagulation are important for reducing false positive and false negative results. Laryngoscope, 131:1188-1193, 2021.

Total Versus Near-total Thyroidectomy in Graves Disease: Results of the Randomized Controlled Multicenter TONIG-trial

BACKGROUND

Previous data suggest that the incidence of hypoparathyroidism after surgery for Graves disease (GD) is lower after subtotal thyroidectomy compared to total thyroidectomy (TT). The present study evaluated the incidence of postoperative hypoparathyroidism after near-total (NTT) versus TT in GD.

METHODS/DESIGN

In a multicenter prospective randomized controlled clinical trial, patients with GD were randomized intraoperatively to NTT or TT. Primary endpoint was the incidence of transient postoperative hypoparathyroidism. Secondary endpoints were permanent hypoparathyroidism, transient recurrent laryngeal nerve palsy (RLNP), reoperations for bleeding, inadvertently removed parathyroid glands, and recurrent hyperthyroidism after 12 months.

RESULTS

Eighteen centers randomized 205 patients to either TT (n = 102) or NTT (n = 103) within 16 months. According to intention-to-treat postoperative transient hypoparathyroidism occurred in 19% (20/103) patients after NTT and in 21% (21 of 102) patients after TT (P = 0.84), which persisted >6 months in 2% and 5% of the NTT and TT groups (P = 0.34). The rates of parathyroid autotransplantation (NTT 24% vs TT 28%, P = 0.50) and transient RLNP (NTT 3% vs TT 4%, P = 0.35) was similar in both groups. The rate of reoperations for bleeding tended to be higher in the NTT group (3% vs 0%, P = 0.07) and the rate of inadvertently removed parathyroid glands was significantly higher after NTT (13% vs 3%, P = 0.01). An existing endocrine orbitopathy improved in 35% and 24% after NTT and TT (P = 0.61). Recurrent disease occurred in only 1 patient after TT (P = 0.34).

CONCLUSION

NTT for GD is not superior to TT regarding transient postoperative hypoparathyroidism.

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.

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.

Inadvertent parathyroidectomy risk factors in 1,373 thyroidectomies-male gender and presence of lymphadenopathy, but not size of gland, independently increase the risk

Background

Inadvertent parathyroidectomy (IP) during thyroid operations is a recognised phenomenon. We evaluated the incidence of IP during thyroid operations in a large case-series and identified the risk factors involved.

Methods

Retrospective review of all thyroidectomy operations [total thyroidectomies (TT) and near-total thyroidectomies (NTT)] performed in a single institution from January 2004 to January 2009. We excluded re-operative cases, combined thyroid and parathyroid pathology, hemithyroidectomies and neck lymph nodes (LN) dissections. Pathology reports were correlated with operative records to identify the details of the IP glands. Relevant data (patient demographic data, preoperative diagnosis and operative details) were collected and a logistic regression was performed.

Results

One thousand three hundred and seventy-three patients were included in our study, 1,149 of them females (84%). IP rate was 11.3%. Univariate analysis showed that gender, thyroid gland weight, thyroid activity pre-operatively and type of operation are associated with IP. Logistic regression analysis has shown that female gender and the absence of LN in pathology were associated with less likelihood in developing IP than males and patients with presence of LN (P=0.051 and 0.014 respectively). IP occurs 2.14 and 2.28 times more often in TT and NTT when compared to the combination of TT and NTT (P=0.047 and 0.048 respectively).

Conclusions

We present the largest single-centre case series on this topic, to our knowledge. The presence of LN, female gender and the type of operation are positively correlated to the IP rate. These factors could alert the surgeon to consider early calcium supplementation if the parathyroid glands (PG) have not been identified intraoperatively.

Evaluation of clinical significance and risk factors of incidental parathyroidectomy due to thyroidectomy: A single-center retrospective clinical study

We assessed the clinical significance and risk factors of incidental parathyroidectomy during total thyroidectomy with or without central neck dissection or subtotal thyroidectomy.Retrospective analysis of clinical and pathological features of 548 consecutive thyroidectomy cases was compared by grouping into inadvertent resection (IR, n = 86) with IR of parathyroid glands, non-IR (n = 462) without, and then into postoperative hypoparathyroidism (PH, n = 140) with PH and non-PH (n = 408) without.Two hundred ninety-eight patients had total thyroidectomy and 250 had subtotal thyroidectomy. IR had higher malignant disease (P < .001), total thyroidectomy (P = .016), T3 and T4 classification (P = .005), central neck dissection (P < .001), recurrent laryngeal nerve palsy (P = .003), postoperative transient hypoparathyroidism (P < .001), duration of disease prior to thyroidectomy (P < .001), and weight of excised thyroid tissue (P < .001) than non-IR.Preoperative diagnosis of malignant disease, duration of disease prior to thyroidectomy, and central neck dissection were independent risk factors for incidental parathyroidectomy. Preoperative diagnosis of malignant disease, central neck dissection, duration of disease prior to thyroidectomy, weight of excised thyroid tissue, and incidental parathyroidectomy were correlated with PH.

Incidental parathyroidectomy during total thyroidectomy is not a direct cause of post-operative hypocalcaemia

BACKGROUND

Post-operative hypocalcaemia is the most common complication after total thyroidectomy, with a reported incidence of transient hypocalcaemia up to 50% and permanent hypocalcaemia 1.5-4%. The impact of incidental parathyroidectomy (IPE) on post-operative hypocalcaemia remains controversial. This study evaluated the risk factors for IPE following total thyroidectomy and compared post-operative calcium levels serially between patients with and without IPE.

METHODS

A retrospective analysis of patients undergoing total thyroidectomy from January 2009 to October 2016 at Western Health was conducted. Histopathology reports were reviewed to identify specimens that included parathyroid tissue. Risk factors and dichotomous data were analysed by exact test of difference in binomial proportions. Group comparison of serial calcium levels (preoperative to 48 h post-operative) between the no IPE and IPE patients were analysed by calculating the area under the curve producing a time series summary.

RESULTS

Four hundred and sixty-eight patients were included: 395 were females (81%), with a median age of 51 years. IPE was confirmed histologically in 84 patients (17.7%) and was more likely to occur in patients undergoing total thyroidectomy with central neck dissection (P = 0.0003), and in patients with malignant disease (P = 0.0005). The difference in area under the curve for serial post-operative calcium levels between the no IPE and the IPE groups was 0.61 (P = 0.21, 95% confidence interval: -0.37 to 1.58).

CONCLUSION

Total thyroidectomy for malignancy and with central node dissection had a higher risk of IPE but did not result in significant changes in post-operative serum calcium levels.

Incidental parathyroidectomy during thyroidectomy increases the risk of postoperative hypocalcemia

OBJECTIVES/HYPOTHESIS

The correlation between incidental parathyroidectomy (IP) during thyroidectomy and postoperative hypocalcemia remains controversial. Our aim was to investigate the incidence of IP, risk factors, and impact on patient outcomes.

STUDY DESIGN

Retrospective cohort study.

METHODS

This was a retrospective observational study including 3,186 consecutive patients who underwent thyroidectomy between January 2007 and December 2014. The patients were divided into two groups: the IP group and the non-IP. Numerous clinical parameters were collected and analyzed.

RESULTS

The overall incidence of incidentally excised parathyroid glands during thyroidectomy was 6.4%. Patients with IP had significantly higher incidences of postoperative hypocalcemia and hypoparathyroidism than those without IP (P < 0.001). Intrathyroidal parathyroid glands presented only 2.2% of all removed parathyroid glands. Total thyroidectomy, central compartment lymph node dissection, and reoperation were independent risk factors for IP.

CONCLUSION

Incidental parathyroidectomy during thyroidectomy is associated with the increased likelihood of postoperative hypocalcemia. All independent risk factors examined in the study for IP are surgery-related. Surgeons should perform meticulous dissection with the intention of avoiding IP and resultant hypocalcemia.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2194-2200, 2017.

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.

Outcomes of Parathyroid Autotransplantation During Total Thyroidectomy: A Comparison with Age- and Sex-Matched Controls

PURPOSE

To determine the effect of parathyroid autotransplantation (PA) on postoperative hypocalcemia in cases of total thyroidectomy.

MATERIALS AND METHODS

Cases undergoing total thyroidectomy and PA were compared with age and sex-matched controls who had not undergone PA. The postoperative percentage changes (PC) of parathyroid hormone (PTH) and calcium (Ca+2) in the first 12-24 hours (12-24hr→preop), between the 1st-3rd weeks (1-3wk→preop) and at the 6th month (6mo→preop), the rates of hypocalcemia (Ca+2< 8mg/dL) and low PTH level (PTH< 15 pg/mL), permanent hypocalcemia, inadvertent parathyroidectomy in both groups were compared.

RESULTS

The number of patients with PTH12-24hr<15 pg/mL was significantly higher (n:34,(55.7%)) than the number of patients in the control group (n:16(26.2%)), (p=0.001). The rate of decrease in the blood Ca+2 median PC (6mo→preop) was significantly higher in the PA group (4.2%) than the control group (1.1%), (p=0.008). There was no significant difference between the 2 groups in terms of the postoperative frequency of hypocalcemia (p>0.05). In the PA&age≤50 group, the rate of inadvertent parathyroidectomy was higher than that of cases over age 50 (p=0.029).

CONCLUSION

In spite of the presence of an increased postoperative hypocalcemia trend in cases requiring PA during total thyroidectomy, the rates of transient and permanent hypocalcemia were not different to the control cases. But the frequency of cases with low PTH level in cases undergoing PA was higher than that of the control cases. In cases of 50 years of age and under, who had undergone PA, the possibility of inadvertent parathyroidectomy increased.

Inadvertent parathyroidectomy: incidence, risk factors, and outcomes

BACKGROUND

Parathyroid glands are ≤5 mm, often subcapsular or intrathyroidal, and obscured by lymph nodes, making preservation a challenge. The purpose of this study was to determine the incidence of inadvertent parathyroidectomy (IP) and whether it contributes to hypoparathyroidism after thyroidectomy.

MATERIALS AND METHODS

A retrospective review of all thyroidectomies by a single surgeon from January 2010 to August 2014 was completed to determine the rate of IP and permanent hypoparathyroidism. Medical records were assessed for demographics, extent of thyroidectomy, central compartment neck dissection, thyroid gland weight, parathyroid autotransplantation, reoperation, pathology, postoperative calcium levels, and number of parathyroid glands removed.

RESULTS

A total of 386 patients underwent thyroidectomy. Mean age was 52 y, and 327 (85%) patients were women. There were 25 (7%) patients who underwent reoperation, 40 (10%) who underwent central compartment neck dissection, and 128 (33%) who underwent parathyroid autotransplantation. IP occurred in 78 (20%) patients. Permanent hypoparathyroidism occurred in 7 (2.7%) of 258 patients after total or completion thyroidectomy, four (6.7%) with IP compared with three (1.5%) without IP (P = 0.033). Logistic regression analysis revealed that female gender (odds ratio = 2.768, P = 0.040), central compartment neck dissection (odds ratio = 9.584, P = 0.001), and thyroid gland weight (odds ratio = 0.994, P = 0.022) were independent factors associated with IP.

CONCLUSIONS

IP, which occurred in 20% of patients undergoing thyroidectomy, is a potentially remediable factor associated with a higher rate of hypoparathyroidism. Central compartment neck dissection is an independent risk factor for IP.

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

OBJECTIVE

The present study evaluated effects of incidental parathyroidectomy, surgical technique, and presence of thyroiditis or hyperthyroidism on occurrence of postoperative persistent or transient hypocalcemia.

METHODS

Patients who underwent thyroidectomy at İstanbul Medeniyet University between 2013 and 2015 were included in the study. Patient information, postoperative serum calcium levels, and pathology reports were investigated retrospectively. Group 1 was made up of patients who were found to have hypocalcemia (calcium ≤8.5 mg/dL) according to postoperative serum level and normocalcemic patients were placed in Group 2. Groups were compared statistically in terms of rate of incidental parathyroidectomy, surgical technique, and presence of thyroiditis or hyperthyroidism.

RESULTS

Mean age was 49.8±12.8 years (range: 20-88). A total of 417 patients were included in the study, 74 (17.7%) were male and 343 (82.3%) were female. Group 1 consisted of 205 (49.2%) patients who had hypocalcemia according to postoperative serum level, and remaining 212 (50.8%) patients were placed in Group 2. In Group 1, 38 (18.5%) patients had incidental parathyroidectomy, and with only 18 (8.5%) patients in Group 2, a statistically significant relationship was found between incidental parathyroidectomy and hypocalcemia (p=0.003). There was no statistically significant difference in terms of presence of thyroiditis or hyperthyroidism between groups. There was statistically significant decrease in postoperative hypocalcemia rate in patients with lobectomy compared to patients with bilateral total thyroidectomy or central neck dissection (p<0.01).

CONCLUSION

Risk of postoperative hypocalcemia may be reduced with lobectomy for selected patients. In addition, delicate dissection during thyroidectomy is important in order to protect parathyroid glands and prevent hypocalcemia.

Incidental Parathyroidectomy during Total Thyroidectomy: Risk Factors and Consequences

Objective. To evaluate the incidence of accidental parathyroidectomy in our series of total thyroidectomies, to investigate its clinical and biochemical consequences, and to identify potential risk factors. Methods. Patients who underwent total thyroidectomy between January 2006 and December 2015 were retrospectively analyzed. Pathology reports were reviewed to identify those cases who had an incidental parathyroidectomy and these were compared to patients with no parathyroidectomy, in terms of clinical (age, sex, and symptoms of hypocalcemia), pathological (thyroid specimen weight, Hashimoto thyroiditis, and malignancy), and biochemical (serum calcium and phosphate levels) factors. Results. 281 patients underwent total thyroidectomy during the study period. Incidental parathyroidectomy was noticed in 24.9% of cases, with 44.3% of parathyroid glands found in an intrathyroidal location. Evidence of postoperative biochemical hypocalcemia was noticed in 28.6% of patients with parathyroidectomy, compared with 13.3% in the no-parathyroidectomy group (p = 0.003). Symptomatic hypocalcemia was observed in 5.7% and 3.8%, respectively (p = 0.49). Age, sex, thyroid specimen weight, Hashimoto thyroiditis, and malignancy did not differ significantly between the two groups. Conclusions. Our study found an association of incidental parathyroidectomy with transient postoperative biochemical hypocalcemia, but not with clinically symptomatic disease. Age, sex, thyroid gland weight, Hashimoto thyroiditis, and malignancy were not identified as risk factors.

Label-free intraoperative parathyroid localization with near-infrared autofluorescence imaging

CONTEXT

The inability to accurately localize the parathyroid glands during parathyroidectomy and thyroidectomy procedures can prevent patients from achieving postoperative normocalcemia. There is a critical need for an improved intraoperative method for real-time parathyroid identification.

OBJECTIVE

The objective of the study was to test the accuracy of a real-time, label-free technique that uses near-infrared (NIR) autofluorescence imaging to localize the parathyroid.

SETTING

The study was conducted at the Vanderbilt University endocrine surgery center.

SUBJECTS AND METHODS

Patients undergoing parathyroidectomy and/or thyroidectomy were included in this study. To validate the intrinsic fluorescence signal in parathyroid, point measurements from 110 patients were collected using NIR fluorescence spectroscopy. Fluorescence imaging was performed on 6 patients. Imaging contrast is based on a previously unreported intrinsic NIR fluorophore in the parathyroid gland. The accuracy of fluorescence imaging was analyzed in comparison with visual assessment and histological findings.

MAIN OUTCOME MEASURE

The detection rate of parathyroid glands was measured.

RESULTS

The parathyroid glands in 100% of patients measured with fluorescence imaging were successfully detected in real time. Fluorescence images consistently showed 2.4 to 8.5 times higher emission intensity from the parathyroid than surrounding tissue. Histological validation confirmed that the high intrinsic fluorescence signal in the parathyroid gland can be used to localize the parathyroid gland regardless of disease state.

CONCLUSION

NIR fluorescence imaging represents a highly sensitive, real-time, label-free tool for parathyroid localization during surgery. The elegance and effectiveness of NIR autofluorescence imaging of the parathyroid gland makes it highly attractive for clinical application in endocrine surgery.

Dissection and identification of parathyroid glands during thyroidectomy: association with hypocalcemia

BACKGROUND

The purpose of this study was to evaluate preoperative features, surgical details, and postoperative findings related to the identification of parathyroid glands and to establish the relationship between identification of parathyroid glands and postoperative hypocalcemia.

METHODS

Seven hundred eighty-eight total thyroidectomies performed between January 2002 and April 2012 by a single surgeon were studied. To evaluate the impact of parathyroid glands identification on study variables, patients were stratified into 2 study groups: group 1 with 0 to 2 parathyroid glands identified and group 2 with 3 to 4 parathyroid glands identified.

RESULTS

Multivariate analysis identified younger age (p = .007), female sex (p = .001), and no usage of the Biclamp hemostatic technique (p < .001) related to the higher number of parathyroid glands identified. Univariate analysis revealed a higher incidence of temporary hypocalcemia (p = .015) and permanent hypoparathyroidism (p = .040) in group 2 than in group 1.

CONCLUSION

Identification of a higher number of parathyroid glands is associated with a higher incidence of postoperative temporary hypocalcemia and permanent hypoparathyroidism.

Incidental parathyroidectomy during thyroid surgery using capsular dissection technique

OBJECTIVE

To identify incidence, preoperative features, surgical factors, and postoperative events of incidental parathyroidectomy (IP) during thyroidectomy.

STUDY DESIGN

A total of 1068 consecutive patients who underwent thyroidectomy performed by a single surgeon between January 2003 and April 2012 were enrolled in retrospective study with prospectively collected data.

SETTING

University hospital.

SUBJECTS AND METHODS

To assess the impact of IP on study variables, patients were stratified into 2 study groups: IP group and non-IP group. Univariate and multivariate analyses identified significant correlates of IP.

RESULTS

In all, 5.4% patients experienced IP. Significant difference (P < .001) was in incidence of temporary hypocalcemia between IP group (36.2%) and non-IP group (16.8%). Multivariable logistic regression model identified total thyroidectomy (odds ratio 3.937, 95% confidence interval [CI] 1.462-10.601, P = .007) and Graves' disease (odds ratio 2.192, 95% CI 1.157-4.158, P = .016) as risk-adjusted factors associated with IP. Multivariate analysis of repeated measures identified statistically significant difference of repeated total calcium level (P < .001) and ionized calcium level (P = .020) between study groups.

CONCLUSION

IP during thyroidectomy might be potential complication. Total thyroidectomy, Graves' disease, longer operation time, and identification 3 and more parathyroid glands seemed to be predictive factors for IP. IP is significantly associated with temporary hypocalcemia, but not with permanent hypoparathyroidism.

Total versus near-total thyroidectomy in Graves' disease and their outcome on postoperative transient hypoparathyroidism: study protocol for a randomized controlled trial?

BACKGROUND

Graves' disease is an independent risk factor for transient postoperative hypoparathyroidism. Besides the disease itself, preparation techniques are influential. Transient postoperative hypoparathyroidism has severe consequences for patients' physical and psychological state. It can be life threatening during the acute phase and may impair patients' health, psyche and quality of life thereafter. For the surgical therapy of Graves' disease, total thyroidectomy is recommended according to the national S2-guideline. The evidence- based on a metaanalysis- is criticized by the Cochrane diagnostic review commentary for substantial methodological deficits. Two randomized controlled trials lead to the hypothesis that a near-total resection with bilateral remnants of ≤ 1g on each side compared to total thyroidectomy will significantly reduce the occurrence of transient postoperative hypoparathyroidism with equal therapeutic safety.

METHODS/DESIGN

Patients with Graves' disease indicated for definite surgery are eligible for the trial. Trial-specific exclusion criteria are: conservative treatment, malignancy, previous thyroid surgery and coincident hypoparathyroidism. The trial is created for therapeutic purpose through process innovation. It is designed as a prospective randomized controlled patient and observer blinded multicentered trial in a parallel design including an active comparator and an intervention group. The intervention addresses the surgical procedure: near-total thyroidectomy leaving bilateral remnants of ≤ 1g on each side in the intervention group and total thyroidectomy in the control group. The occurrence of transient postoperative hypoparathyroidism is defined as primary endpoint. Secondary endpoints are: reoperations due to bleeding, recurrent laryngeal nerve palsy, permanent hypoparathyroidism, recurrent disease, changes of endocrine orbitopathy and quality of life within a one-year follow-up period. The primary efficacy analysis follows the intention-to-treat principle. A binary logistic regression model will be applied. Complications and serious adverse events will be descriptively analyzed.

DISCUSSION

The trail is expected to balance out the shortcomings of the current evidence. It will define the surgical gold standard for the surgical therapy of Graves' disease. Patients' safety and quality of life are assumed to be enhanced. Therapy costs are likely to be reduced and health care optimized. The conduction of the trial is feasible through the engagement and commitment of the German association of endocrine surgeons and the National Network for Surgical Trials.

TRIAL REGISTRATION

German clinical trials register (DRKS) DRKS00004161.

Risk factors for incidental parathyroidectomy during thyroidectomy

Incidental parathyroidectomy is a common event in thyroid surgery. The literature shows a finding of parathyroid glands ranging from 6.4% to 31% in pathological specimens of the thyroid gland.

Objective

To collect the amount of parathyroid glands found in surgical specimens of thyroidectomy and correlate with the histopathological and demographic variables.

Methods

Retrospective study based on pathological reports of thyroidectomy from January 2007 to December 2008.

Results

442 patients were submitted to total thyroidectomy, and 2.93% had parathyroid glands, which corresponded to 13 of this total. The presence of papillary thyroid carcinoma associated with incidental parathyroidectomy was 10.11%, compared to the benign lesion: 1.4%.

Conclusion

Papillary thyroid carcinoma was the variable associated with increased number of incidental parathyroidectomy.

UltraCision harmonic scalpel versus clamp-and-tie total thyroidectomy: a clinical trial

BACKGROUND

Hemostasis is important in thyroid surgery to avoid complications. Our aim was to evaluate the effectiveness of the harmonic scalpel in patients undergoing total thyroidectomy.

METHODS

In this study, 90 patients were randomized into group A (classic technique of tying and knots) and group B (harmonic scalpel). We recorded the following: age, sex, pathology, thyroid weight, hemostatic technique, duration of operation, change in calcemia (DeltaCa), change in hematocrit (DeltaHt), change in hemoglobin (DeltaHgb), change in white blood cell count (DeltaWBC), vocal motility, operative difficulty, postoperative vocal alteration, postoperative pain, complications, blood in the drains, operating time, mass of gland excised per minute, and hospitalization.

RESULTS

Differences (p < .05) were observed concerning duration of surgery, operative difficulty, postoperative pain, hospitalization, DeltaWBC, and quantity of gland removed per minute. No recurrent laryngeal nerve (RLN) palsies were observed.

CONCLUSIONS

Use of the Harmonic Scalpel in total thyroidectomy is more effective than the clamp-and-tie technique: the duration of surgery, intraoperative difficulty, postoperative pain, and hospitalization are reduced. Both techniques are equivalent concerning RLN injuries, postoperative vocal alterations, and blood loss.

Risk Factors and Consequences of Incidental Parathyroidectomy during Thyroidectomy

The objectives of this retrospective study were to investigate the incidence, risk factors, and clinical significance of incidental parathyroidectomy during thyroidectomy. In this study, there were 315 patients who underwent thyroidectomy between 1996 and 2006. All the operations were performed by a single experienced surgeon (J.S.). Pathology reports on all specimens were reviewed and information regarding patient demographics, diagnosis, operative details, and postoperative complications were collected. A total of 315 thyroidectomies were performed: 101 total thyroidectomies (32.1%) and 214 subtotal thyroidectomies (67.9%). Two hundred and eighty patients were operated on for benign disease (88.9%) and 35 for malignant disease (11.1%). Incidental parathyroidectomy was identified in 32 cases (10.2%). Preoperative diagnosis of malignant disease ( P = 0.009) and duration of the disease ( P = 0.001) were significant predictors of incidental parathyroidectomy. Incidental parathyroidectomy was significantly correlated with postoperative hypoparathyroidism ( P = 0.03). Transient postoperative hypoparathyroidism occurred in 18 cases (6%) and permanent in three cases (1%). The duration of the disease was the sole significant predictor of postoperative hypoparathyroidism ( P < 0.001). Incidental parathyroidectomy seems to be the result of the use of extensive surgical procedures. The preoperative diagnosis of malignant disease and the delay of the operation, which leads to a more advanced thyroid disease, make the use of extensive surgical procedures necessary.