How many parathyroid glands can be identified during thyroidectomy?: Evidence-based data for medical experts

Parathyroid gland identification and angiography classification using simple machine learning methods

BACKGROUND

Near-infrared indocyanine green angiography allows experienced surgeons to reliably evaluate parathyroid gland vitality during thyroid and parathyroid operations in order to predict postoperative function. To facilitate equal performance between surgeons, we developed an automatic computational quantification method using computer vision that portrays expert interpretation of visualized parathyroid gland near-infrared indocyanine green angiographic fluorescence signals.

METHODS

Near-infrared indocyanine green-parathyroid gland angiography video recordings (Fluobeam® LX, Fluoptics, Grenoble-part of Getinge-Göteborg) from patients undergoing endocrine cervical surgery in a high-volume unit were used for model development. Computation (MATLAB, Mathworks, Ireland) included segmentation-identification of the parathyroid gland (by autofluorescence), image stabilization (by linear translation) and adjusted time-fluorescence intensity profile generation. Relative upslope and maximum intensity ratios then trained a simple logistic regression model based on expert interpretation and outcome (including hypoparathyroidism), with subsequent unseen testing for validation.

RESULTS

The model was trained on 37 patient videos (45 glands, 29 judged well perfused by parathyroid gland angiography experts), achieving feature data separation with 100% accuracy, and tested on 22 unseen videos (27 glands, 15 judged well perfused), including four in real time. Segmentation-guided parathyroid gland detection correctly identified all parathyroid glands during unseen testing along with three additional non-parathyroid gland regions (90% positive predictive value). Subsequent time-fluorescence intensity profile extraction with vitality prediction was shown feasible in all cases within 5 min, with a 96.3% model accuracy (sensitivity and specificity were 93.3 and 100% respectively) when compared with expert judgement.

CONCLUSION

Automatic parathyroid gland perfusion quantification using simple machine learning computational methods discriminates parathyroid gland perfusion in concordance with expert surgeon interpretation, providing a means for near-infrared indocyanine green-parathyroid gland signal evaluation.

Activation of the Calcium-Sensing Receptor by a Subfraction of Amino Acids Contained in Thyroid Drainage Fluid

Hypoparathyroidism is a common sequela of thyroid surgery; in this study, we aimed at exploring the pathogenesis behind it. The following premises suggest that wound fluid might be a causative agent. (i) Parathyroid hormone secretion is under feedback control by the calcium-sensing receptor, which responds to a diverse array of activating ligands. (ii) Postoperative hypoparathyroidism arises from a secretory deficiency of the parathyroid glands. Even in patients later unaffected by hypoparathyroidism, parathyroid hormone levels drop within hours after surgery. (iii) Wound fluid is bound to enter the tissue around the thyroid bed, where the parathyroid glands are located. Its composition is shaped by a series of proteolytic reactions triggered by wounding. Using thyroid drainage as a surrogate, we addressed the possibility that wound fluid contains compounds activating the calcium-sensing receptor. Drainage fluid ultrafiltrate was found to be rich in amino acids, and on separation by HPLC, compounds activating the calcium-sensing receptor partitioned with hydrophilic matter that rendered buffer acidic. The data show that glutamate and aspartate at millimolar concentrations supported activation of the calcium-sensing receptor, an effect contingent on low pH. In the presence of glutamate/aspartate, protons activated the calcium-sensing receptor with a pH50 of 6.1, and at pH 5, produced maximal activation. This synergistic mode of action was exclusive; glutamine/asparagine did not substitute for the acidic amino acids, nor did Ca2+ substitute for protons. NPS-2143, a negative allosteric receptor modulator completely blocked receptor activation by glutamate/aspartate and by fractionated drainage fluid. Thus, wound fluid may be involved in suppressing parathyroid hormone secretion.

Total Number of Identified Parathyroid Glands During Total Thyroidectomy and Its Relation to Postoperative Hypoparathyroidism

OBJECTIVES

To evaluate the correlation between the intraoperative number of identified parathyroid glands (PGs) and the risk of developing hypoparathyroidism postoperatively. Also, to determine the risks and prognostic factors in patients with postoperative hypoparathyroidism.

METHODS

A retrospective study of 499 patients who underwent total thyroidectomy at two tertiary care institutions, King Saud University Medical City (KSUMC) and King Fahad Medical City (KFMC) in Riyadh, Saudi Arabia was included. Individual demographic characteristics with detailed clinical information were recorded, focusing mainly on operative reports for a total number of identified PGs intraoperatively and investigating the risk of developing hypoparathyroidism postoperatively. Factors such as age, gender, comorbidity, and number of excised and reimplanted parathyroid glands were investigated to determine the risks and prognostic factors in patients with postoperative hypoparathyroidism.

RESULTS

The findings from the analysis showed that the number of identified PGs intraoperatively had a positive correlation with a higher postoperative risk of developing hypoparathyroidism. For zero, one, two, three, and four identified PGs, the risk of hypoparathyroidism in one-hour parathyroid hormone level postoperative was 6.6%, 7.3%, 34.4%, 34.4%, and 17.2% respectively.

CONCLUSION

The greater the number of identified PGs intraoperatively, the less likely it was to prevent inadvertent hypoparathyroidism post-total thyroidectomy.

Preoperative ultrasound identification and localization of the inferior parathyroid glands in thyroid surgery

INTRODUCTION

The parathyroid glands are important endocrine glands for maintaining calcium and phosphorus metabolism, and they are vulnerable to accidental injuries during thyroid cancer surgery. The aim of this retrospective study was to investigate the application of high-frequency ultrasound imaging for preoperative anatomical localization of the parathyroid glands in patients with thyroid cancer and to analyze the protective effect of this technique on the parathyroid glands and its effect on reducing postoperative complications.

MATERIALS AND METHODS

A total of 165 patients who were operated for thyroid cancer in our hospital were included. The patients were assigned into two groups according to the time period of surgery: Control group, May 2018 to February 2021 (before the application of ultrasound localization of parathyroid in our hospital); PUS group, March 2021 to May 2022. In PUS group, preoperative ultrasound was used to determine the size and location of bilateral inferior parathyroid glands to help surgeons identify and protect the parathyroid glands during operation. We compared the preoperative ultrasound results with the intraoperative observations. Preoperative and first day postoperative serum calcium and PTH were measured in both groups.

RESULTS

Our preoperative parathyroid ultrasound identification technique has more than 90% accuracy (true positive rate) to confirm the location of parathyroid gland compared to intraoperative observations. Postoperative biochemical results showed a better Ca²⁺ [2.12(0.17) vs. 2.05(0.31), P=0.03] and PTH [27.48(14.88) vs. 23.27(16.58), P=0.005] levels at first day post-operation in PUS group compared to control group. We also found a reduced risk of at least one type of hypoparathyroidism after surgery in control group:26 cases (31.0%) vs. 41 cases (50.6%), p=0.016.

CONCLUSION

Ultrasound localization of the parathyroid glands can help in the localization, identification and in situ preservation of the parathyroid glands during thyroidectomy. It can effectively reduce the risk of hypoparathyroidism after thyroid surgery.

Near-infrared fluorescent imaging techniques for the detection and preservation of parathyroid glands during endocrine surgery

Objectives

In over 30% of all thyroid surgeries, complications arise from transient and definitive hypoparathyroidism, underscoring the need for real-time identification and preservation of parathyroid glands (PGs). Here, we evaluate the promising intraoperative optical technologies available for the identification, preservation, and functional assessment of PGs to enhance endocrine surgery.

Methods

We performed a review of the literature to identify published studies on fluorescence imaging in thyroid and parathyroid surgery.

Results

Fluorescence imaging is a well-demonstrated approach for both in vivo and in vitro localization of specific cells or tissues, and is gaining popularity as a technique to detect PGs during endocrine surgery. Autofluorescence (AF) imaging and indocyanine green (ICG) angiography are two emerging optical techniques to improve outcomes in thyroid and parathyroid surgeries. Near-infrared-guided technology has significantly contributed to the localization of PGs, through the detection of glandular AF. Perfusion through the PGs can be visualized with ICG, which can also reveal the blood supply after dissection.

Conclusions

Near infrared AF and ICG angiography, providing a valuable spatial and anatomical information, can decrease the incidence of complications in thyroid surgery.

The utility of indocyanine green (ICG) for the identification and assessment of viability of the parathyroid glands during thyroidectomy

We conducted this study to evaluate the ability of indocyanine green (ICG) and near infra-red fluorescence (NIRF) camera to aid in the identification and assessment of viability of parathyroid glands during thyroid surgery. A prospective observational study was conducted between May and October 2020 among 50 consecutive patients who underwent total thyroidectomy at a single institution. Parathyroid glands were identified under white light during thyroidectomy following which reconstituted ICG was injected through a peripheral vein and the location of parathyroid glands was confirmed. The perfusion to the parathyroid gland was assessed by documenting the fluorescence intensity score (FIS) and the parathyroid angiogram score (PAS). There was no difference in the number of parathyroid glands seen on visual inspection 147 (73.5%) when compared to under NIRF camera, 146 (73%). Though the rate of postoperative hypoparathyroidism was lower in the cohort with FIS 3 (14.2%) compared to score 2 and 1 (28.5% and 100%, respectively), this was not significant (p = 0.35). A significant correlation was noted between a delayed flow on PAS and the development of post-thyroidectomy hypoparathyroidism (p = 0.01). PAS had a sensitivity of 100%, specificity of 88.6%, NPV of 100% and PPV of 55.6% to predict the development of post-thyroidectomy hypoparathyroidism. In this study, there was no additional benefit of ICG and NIRF camera in the identification of parathyroid glands. However, ICG angiogram seems to be a good adjunct for the intraoperative assessment of the viability of the parathyroid glands and accurately predicts the development of postoperative hypoparathyroidism.

[Prevention and treatment of postoperative hypoparathyroidism]

Hypoparathyroidism is a failure of parathyroid glands characterized by reduced serum concentration of parathyroid hormone, hypocalcemia and hyperphosphatemia. The most common cause of hypoparathyroidism is resection or damage to parathyroid glands during thyroid surgery. Postoperative hypoparathyroidism is still an urgent problem, as it requires additional treatment and prolongs hospital-stay. Considering available literature data, the authors analyze various methods of intraoperative prevention of hypoparathyroidism.

Association between number of parathyroid glands identified during total thyroidectomy and functional parathyroid preservation

Purpose

Systematic identification of all 4 parathyroid glands has been recommended during total thyroidectomy (TT); however, it is unclear whether this strategy necessarily translates into optimized functional parathyroid preservation. We wished to investigate the association between number of parathyroids identified intraoperatively during TT, and incidence of incidental parathyroidectomy, and postoperative hypoparathyroidism.

Methods

Retrospective review of prospectively maintained database of 511 consecutive patients undergoing TT at an academic teaching hospital. The association between number of parathyroid glands identified intraoperatively and incidence of biochemical hypocalcaemia (defined as any calcium < 2 mmol/L n first 48 h after surgery), symptomatic hypocalcaemia; permanent hypoparathyroidism (defined as any hypocalcaemia or need for calcium or vitamin D > 6 months after surgery), and incidental parathyroidectomy, was investigated. The association between number of parathyroid glands visualized and postoperative parathyroid hormone (PTH) levels was investigated in a subset of 454 patients.

Results

Patients in whom a greater number of parathyroids had been identified had a significantly higher incidence of biochemical and symptomatic hypocalcaemia, and significantly lower postoperative PTH levels, than patients with fewer glands identified. There were no significant differences in incidence of permanent hypoparathyroidism or incidental parathyroidectomy. On multivariate analysis, malignancy, Graves disease, and identification of 3–4 parathyroids were independent predictors of biochemical hypocalcaemia. For symptomatic hypocalcaemia, identification of 2–4 parathyroids, and identification of 3–4 parathyroids, were significant.

Conclusions

Systematic identification of as many parathyroid glands as possible during TT is not necessary for functional parathyroid preservation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00423-021-02287-6.

Does number of autotransplanted parathyroid glands affects postoperative hypoparathyroidism and serum parathyroid hormone levels?

BACKGROUND

To investigate how number of autotransplanted parathyroid glands (PGs) affects the incidence of postoperative hypoparathyroidism and the recovery of parathyroid function.

METHODS

A systematic search was performed in the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases. The evaluated indices included the incidence of postoperative transient and permanent hypoparathyroidism and parathyroid hormone (PTH) levels during follow-up.

RESULTS

Twenty articles with 7291 patients were included. A higher incidence of transient hypoparathyroidism was found in the PG autotransplantation group than in the preservation group (odds ratio [OR]: 2.37; 95% confidence interval [CI]: 1.90, 2.96). However, there was no significant difference between the two groups regarding permanent hypoparathyroidism (OR: 1.17; 95% CI: 0.71, 1.91). Parathyroid hormone (PTH) levels in the PG autotransplantation group changed significantly more than the preservation group at postoperative 1-day and 1-month, but became similar at the 6-month, 1-year and 2-year follow-up. Autotransplantation of 2 and 3 PGs demonstrated a higher incidence of transient hypoparathyroidism than 1 PG (OR: 2.09; 95% CI: 1.41, 3.11 and OR: 9.70; 95% CI: 2.11, 44.39, respectively), but no significant difference was observed between the autotransplantation of 3 and 2 PGs (OR: 0.99; 95% CI: 0.03, 29.06). Additionally, the incidence of permanent hypoparathyroidism was not significantly different when different number of PGs was autotransplanted.

CONCLUSIONS

PG autotransplantation is an effective mid- and long-term strategy for the preservation of parathyroid function. Although transient hypoparathyroidism was positively correlated with the number of autotransplanted PGs, no remarkable correlation was observed for permanent hypoparathyroidism.

Potential protection of indocyanine green on parathyroid gland function during near-infrared laparoscopic-assisted thyroidectomy: A case report and literature review

BACKGROUND

In recent decades, significant advances have been made in protecting the parathyroid glands and recurrent laryngeal nerves during thyro-idectomy. However, reliable and convenient technical means are still lacking. In this study, the reliability, safety and feasibility of near-infrared (NIR) laparoscopy-assisted thyroid lobectomy with isthmectomy and prophylactic central lymph node dissection (CLND) were reported.

CASE SUMMARY

A 63-year-old female patient with a free previous medical history, was admitted to our department due to multiple thyroid nodules. Ultrasonic examination suggested diffuse thyroid changes and one thyroid nodule in the right upper lobe with the largest diameter of 1.5 cm adjacent to the trachea and Breast Imaging Reporting and Data System grade 4B. Imaging examination of the neck showed no obvious enlarged lymph nodes. Fine needle aspiration biopsy suggested a papillary thyroid carcinoma. Combined with thyroid function examination, the patient was diagnosed with papillary thyroid carcinoma and Hashimoto's thyroiditis. Considering the risk of invading the capsule and the patient's extreme anxiety, a right thyroid lobectomy with isthmectomy and prophylactic CLND was planned. No significant abnormalities were found during preoperative examinations, except for an increased thyroid stimulating hormone level. The patient underwent NIR laparoscopy-assisted thyroid lobectomy with isthmectomy and prophylactic CLND. During the operation, two right parathyroid glands (PGs) adjacent to the thyroid gland capsule and the right recurrent laryngeal nerve (RLN) were examined by indocyanine green (ICG) fluorescence using a NIR fluorescence camera, and the PGs and RLN were reliably preserved. Considering the ICG-positive PG, prophylactic CLND was performed. The postoperative parathyroid hormone level was in the normal range and no significant hypocalcemia symptoms were observed.

CONCLUSION

During NIR laparoscopy-assisted thyroidectomy, ICG fluorescence may aid PG identification and protection.

Development and validation of a new model for predicting hypocalcaemia after total thyroidectomy: the NuGra model

BACKGROUND

Hypocalcaemia is the most frequent complication after total thyroidectomy. Finding a method for its early detection has become a priority. A single-center prospective cohort study was conducted to identify risk factors for postoperative hypocalcaemia, develop an early detection model, and test its validity in a different group of patients.

METHODS

The sample was composed of patients who underwent a total thyroidectomy between May 2012 and September 2015. Demographic, clinical, laboratory, and surgical data were collected. The incidence of hypocalcaemia and permanent hypoparathyroidism was calculated. Bivariate and multivariate analysis identified several independent predictors of hypocalcaemia, which were used to design a predictive model. The validity of the model was subsequently tested in a different cohort. Area under the ROC curve (AUROC) was calculated to determine its predictive power.

RESULTS

The study and validation groups included 352 and 118 patients, respectively. Seventy-three patients developed laboratory-confirmed hypocalcaemia (20.7%), and symptomatic in 43 (12.2%). Multivariate analysis confirmed as independent predictors of hypocalcaemia the higher number of parathyroid glands identified [OR 1.41(0.98, 2.02); p = 0.063] and pre-to-postoperative gradient of parathormone decline [OR 1.06(1.04, 1.08); p < 0.001]. Based on these variables, the NuGra (Number of parathyroid glands identified-Gradient of decline) model was developed for predicting laboratory-confirmed hypocalcaemia. Its predictive power was high (AUROC 0.902, CI 0.857-0.947) for the study and the validation group (AUROC 0.956, CI 0.919-0.993).

CONCLUSIONS

A higher number of parathyroid glands identified and a higher gradient of parathormone decline are risk factors for post-thyroidectomy hypocalcaemia. The NuGra model is useful for early prediction of individual risk for hypocalcaemia.

[Modern thyroid surgery - the surgeon's endocrine-surgical understanding and his responsibility for the extent of surgery and complication rate]

Die hohe Qualität der Schilddrüsenchirurgie impliziert ein endokrin-chirurgisches Verständnis des Operateurs mit dem Ziel einer bestmöglichen Ergebnisqualität. Das beinhaltet ein befundadäquates Resektionsausmaß und eine möglichst niedrige Komplikationsrate. Der Chirurg sollte frühzeitig in die Operationsindikation eingebunden sein und auch selbst die Diagnostik, speziell den Schilddrüsen- und Halslymphknotenultraschall, sowie die Interpretation der Schnittbild- und nuklearmedizinischen Verfahren beherrschen. Im Besonderen sollte er über zeitgemäße Radikalitätsprinzipien in der Chirurgie Bescheid wissen.

Bei der gutartigen Struma ist eine individualisierte Operationsstrategie anzuwenden: Solitärknoten können auch einer gewebeschonenden Knotenresektion unterzogen werden. Bei multinodulärer Knotenstruma ist nicht zwingend eine totale Thyreoidektomie notwendig, die Vermeidung eines permanenten Hypoparathyreoidismus hat Priorität. Bei Rezidivstrumen ist oft die einseitige Operation des dominanten Befundes zu bevorzugen. Auch besteht zunehmend der Trend, die Indikation zur Entfernung der Schilddrüsenlappen seitengetrennt zu stellen. Die Basedow Struma erfordert eine Thyreoidektomie. Auch die hypertrophe Thyreoiditis Hashimoto kann eine Operationsindikation darstellen.

Die Radikalitätsprinzipien bei maligner Struma haben sich ebenfalls deutlich gewandelt als auch die strenge Indikation zur Radiojodtherapie. Das gilt speziell für papilläre Mikrokarzinome und minimal invasive follikuläre Tumortypen. Selbst bei medullären Schilddrüsenkarzinom stehen die Radikalitätsprinzipien im Hinblick auf synchrone oder metachrone laterale Halsdissektion in Diskussion.

Der Hypoparathyreoidismus stellt derzeit das Hauptproblem in der radikalen Schilddrüsenchirurgie dar. Recurrensparese und Nachblutung sind durch die subtile Operationstechnik selten geworden. Spezielle extrazervikale Operationszugänge sind nach wie vor in der Erprobungsphase und unter strengen Studienbestimmungen nur Zentren vorbehalten. Die Radiofrequenzablation stellt für gewisse Läsionen wie Zysten und autonome Adenome bei chirurgischer Kontraindikation ein alternatives Ablationsverfahren dar.

[Hypoparathyroidism - un underestimated problem?]

BACKGROUND

Hypoparathyroidism is a rare and disabilitating disorder characterized by hypocalcemia and low parathyroid hormone levels. Most of the cases occur as a result of the removal of parathyroid glands or damage to the glands during neck surgery. More rare causes include nonsurgical causes such as autoimmune or genetic diseases.

METHOD

In this review, a panel of experts presents the current state of diagnosis and therapy of hypoparathyroidism and explains practical aspects of caring for the affected patients.

RESULTS

Common signs and symptoms are abnormal sensations and increased excitability in the lower limbs, paresthesia of perioral areas and nocturnal leg cramps. Renal complications frequently occur, but also basal ganglia calcification. Treatment consists of administration of vitamin D analogs in combination with 0.5-1.0 g calcium daily. An adjunctive treatment with the in April 2017 approved recombinant human parathyroid hormone (1-84) is an option for patients whose hypoparathyroidism is difficult to control by conventional treatment alone. Initially and after dose changes follow-up controls should be performed at least every 2 weeks, in well-controlled patients or in the case of chronic progression every 3-6 months.

Graves' disease: developments in first-line antithyroid drugs in the young

Introduction: First-line treatment for most young people with Graves' disease (GD) will include the administration of a thionamide antithyroid medication (ATD); Carbimazole (CBZ), Methimazole (MMZ), or rarely, propylthiouracil (PTU). GD is a challenge for families and clinicians because the likelihood of remission following a course of ATD is lower in young people when compared to adults, yet the risk of adverse events is higher. An overall consensus regarding the optimal ATD treatment regimen is lacking; how ATD are prescribed, for how long and how the associated risk of adverse events is managed varies between clinicians, units and nations. This partly reflects clinician and family uncertainty regarding outcomes.Areas covered: This review will focus on some of the key articles published in the field of thionamide ATD in children. It will highlight key issues that need to be discussed with families as well as addressing the approach and controversies in the treatment of GD. This article does not reflect a formal systematic review of the literature.Expert opinion: New strategies in areas such as immunomodulation may see the development of new antithyroid drug treatments that, either in isolation or in combination with thionamide therapy, may increase the likelihood of long-term remission.

Role of Ca²⁺ in Inhibiting Ischemia-Induced Apoptosis of Parathyroid Gland Cells in New Zealand White Rabbits

BACKGROUND Hypoparathyroidism is a common complication after thyroidectomy. Calcium supplementation can relieve these symptoms, but it is not clear whether it can protect the parathyroid glands. This study aimed to verify whether Ca²⁺ inhibits the apoptosis of parathyroid cells following ischemic injury. MATERIAL AND METHODS A rabbit model of parathyroid gland ischemic injury was established. The blood calcium concentrations were measured by colorimetry. The parathyroid hormone (PTH) levels were measured by enzyme-linked immunosorbent assay (ELISA). The parathyroid tissues were observed by hematoxylin and eosin (H&E) staining and the TdT-mediated dUTP nick-end labeling (TUNEL) assay. Western blotting was used to quantify the levels of the following proteins: caspase-3 and p38 MAP Kinase (p38 MAPK). RESULTS This study demonstrates that apoptosis can be a part of the pathological changes associated with parathyroid ischemic injury. Calcium supplementation inhibited the apoptosis of parathyroid cells following ischemic injury. There were no significant differences among the serum calcium levels from the Sham operation (Sham), the Control group (CG), or the Calcium supplementation group (CSG) after 24 h, 72 h, and 168 h of treatment. PTH levels in the CG were significantly higher than in the CSG at 24 h and 72 h after treatments. The apoptosis rate of parathyroid cells from rabbits in the CSG was significantly lower than that of those from rabbits in the CG at 24 h and 72 h after the treatment. Calcium supplementation inhibited p38 MAPK and caspase-3 expression. CONCLUSIONS This study demonstrates that calcium supplementation inhibited the apoptosis of parathyroid cells following ischemic injury.

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).

Video-assisted parathyroid gland mapping with autofocusing

Preservation of the parathyroid gland (PTG) in neck endocrine surgery is important for regulating the amount of calcium in the blood and within the bones. Localization of the PTG has been attempted using various methods such as ultrasound, sestamibi, computerized tomography, magnetic resonance imaging and indocyanine green fluorescence imaging. These methods cannot be used during surgery, have high sensitivity or have PTG specificity. However, autofluorescence technique has shown high sensitivity and does not require exogenous contrast. In this study, a new optical system was designed and developed into a clinical system. The system enabled easier and faster focusing on the surgical area and high-resolution video imaging while maintaining a clear image. The system was located above the head of the surgeon. The surgeon was able to see the real-time autofluorescent image on the monitor next to the operating table at any time to locate the PTG. The PTG buried in the adipose tissue and connective tissue was located easily and accurately. The clinical trial conducted in this study consisted of 56 parathyroid cases in 26 patients. For the statistical results, the sensitivity and accuracy in this redesigned autofluorescent imaging system were 98.1% and 96.4%, respectively.

Complete and incomplete recurrent laryngeal nerve injury after thyroid and parathyroid surgery: Characterizing paralysis and paresis

BACKGROUND

Injury of the recurrent laryngeal nerve and consequent disorder of vocal fold movement is a typical complication in thyroid and parathyroid surgery. During postoperative laryngoscopy we observed not only a complete standstill (vocal fold paralysis), but also a hypomobility (paresis). In this prospective study, we investigated the difference in incidence and prognosis as well as risk-factors, intraoperative neuromonitoring, and symptoms between vocal fold paralysis and vocal fold paresis.

METHODS

Data were prospectively collected and analyzed in a single high-volume thyroid center between 2012 and 2016. Vocal fold paresis was defined as hypomobility in abduction or adduction, a reduction in range and speed of vocal fold movement. Vocal fold paralysis was defined as asymmetry and missing purposeful vocal fold movement.

RESULTS

The study included 4,707 surgeries and 7,992 at-risk nerves at risk. Vocal fold paralysis was diagnosed in 374 patients (4.68% of 7,992 nerves at risk) and vocal fold paresis in 114 patients (1.43%). Exclusively in the paralysis group, 36 patients (0.45%) developed permanent loss of vocal fold function (P < .001). In follow-up, vocal fold paresis patients regain normal vocal fold function significantly earlier than vocal fold paralysis (mean duration: 6.96 ± 6.506 vs 10.77 ± 7,827 weeks) and presented with significantly less symptoms like hoarseness, diplophonia, dysphagia, and dyspnea (68.8% vs 95.9 %). In intraoperative neuromonitoring, vocal fold paresis showed a significantly higher postresectional N. vagus amplitude than vocal fold paralysis patients (0.349 mV vs 0.114 mV, P < .001).

CONCLUSION

After thyroidectomy, vocal fold paresis must be distinguished from vocal fold paralysis and should be implemented as a separate outcome parameter in the postoperative quality assessment.

Feasibility of using colloidal gold immunochromatography for point-of-care identification of parathyroid glands during thyroidectomy

AIM

To determine the feasibility of using colloidal gold immunochromatography for rapid identification of parathyroid glands during thyroidectomy.

MATERIAL AND METHODS

127 patients undergoing thyroidectomy were randomly divided into PTH-ICGT group (64 cases) and conventional naked eye group (63 cases). The rate of identification of parathyroid glands and the incidence of hypoparathyroidism were compared between the two groups.

RESULTS

PTH-CGI assay results showed that PTH concentration in the parathyroid tissue was (955.3 ± 16.1) ng/L; skeletal muscle tissue [(14.5 ± 1.5) ng/L], thyroid tissue [(15.0 ± 1.3) ng/L], adipose tissue [(15.3 ± 1.2) ng/L], lymph node tissue [(14.0 ± 1.2) ng/L];PTH levels in parathyroid tissues were compared with PTH levels in skeletal muscle, thyroid, fat, and lymph node tissues, respectively. The differences were statistically significant(t values were 23.62, 33.42, 39.34, 30.77, P < 0.0001, respectively); Among the 127 patients undergoing total thyroidectomy, the rate of detection of parathyroid glands was 92.7% in the conventional naked eye group and 96.4% in the PTH-ICGT group. There was no significant difference in the detection rate of parathyroid gland between the two groups (χ2 = 0.7067, P = 0.40). The incidence of temporary hypoparathyroidism after surgery in both groups was 11.3% and 5.7%, respectively (χ2 = 1.093, P > 0.05). The incidence of postoperative permanent hypoparathyroidism in both groups was 3.8% and 0, respectively (Fisher's exact test, P = 0.495).

CONCLUSION

PTH-CGI has a high efficiency in identifying parathyroid glands, which may increase the rate of clinical parathyroid detection and reduce the incidence of postoperative hypoparathyroidism.