Inferior thyroid artery ligation increases hypocalcemia after thyroidectomy: A meta-analysis

Impact of parathyroid gland classification on hypoparathyroidism following total thyroidectomy with central neck dissection for differentiated thyroid cancer

OBJECTIVE

To assess the impact of parathyroid gland (PG) classification on hypoparathyroidism incidence following total thyroidectomy (TT) with central neck dissection (CND) in patients with differentiated thyroid carcinoma (DTC).

METHODS

In this prospective cohort study, adult patients with DTC who underwent TT with CND between 2021 and 2023 were enrolled, with a maximum follow-up duration of 32 months. A simplified PG classification system was employed, categorizing glands into four distinct types: tightly connected, loosely connected, non-connected, and thymic. The intraoperative frequency of each PG type was recorded based on this classification. Parathyroid hormone (PTH) levels were routinely tested 1 day, 1 month, 6 months and 1 year after surgery. The association between PG classification and the incidence of postoperative hypoparathyroidism was then systematically analysed.

RESULTS

Among 135 patients with DTC (mean age: 48.50 ± 10.52 years; 101 women), 62 patients (45.93%) developed hypoparathyroidism on postoperative day 1 (POD1), while 14 patients (10.37%) experienced hypoparathyroidism on postoperative month 1 (POM1). All patients exhibited PTH normalization within six months, with no permanent hypoparathyroidism cases. A total of 532 PGs were identified: 264 (49.62%) were tightly connected, 150 (28.20%) loosely connected, 95 (17.86%) non-connected, and 23 (4.32%) thymic. The highest prevalence of hypoparathyroidism on POD1 was observed in patients with four tightly connected PGs (p < 0.001). Patients with four tightly connected PGs had a significantly greater incidence of hypoparathyroidism than those with none (p = 0.024). Regression analysis revealed that each additional tightly connected PG increased the risk of hypoparathyroidism by 1.38 times (p = 0.019). Tightly connected PGs demonstrated predictive value for POD1 hypoparathyroidism (AUC = 0.604, cut-off: two tightly connected glands). In contrast, thymic PGs did not provide a protective effect.

CONCLUSION

PG classification may serve as a valuable tool for surgeons in intraoperative parathyroid preservation and the prediction of postoperative hypoparathyroidism in patients with DTC. Notably, DTC patients with more than two tightly connected PGs are at an elevated risk of developing temporary hypoparathyroidism, emphasizing the importance of meticulous parathyroid preservation during surgical procedures.

Predictive factors for permanent hypoparathyroidism following total thyroidectomy: A retrospective cohort study of 5,671 cases

OBJECTIVE

To evaluate the rates of permanent hypoparathyroidism based on demographic variables, patient comorbidities, clinical staging of the disease, surgery performed, and severity of transient hypoparathyroidism.

SUBJECTS AND METHODS

This is a retrospective cohort study with patients who underwent total thyroidectomy with or without neck dissection between January 2014 and December 2021.

RESULTS

5,671 patients were analyzed, 966 (17)%) presented transient hypoparathyroidism and 106 (1.8%) developed permanent hypoparathyroidism. The logistic regression model analyzing the cohort of patients with transient hypoparathyroidism demonstrates that the number of dissected lymph nodes from the central compartment, immediate postoperative PTH levels, the necessity of postoperative intravenous (IV) calcium supplementation and the duration of IV calcium supplementation are significant predictors. When applied to the original dataset, this model presents a NPV of 1.0000 and a PPV of 0.9594 with an overall accuracy of 0.9624.

CONCLUSION

The incidence of permanent hypoparathyroidism was closely associated with the extent of level VI dissection, particularly regarding the number of lymph nodes removed and whether the dissection was bilateral. Furthermore, the severity of post-operative hypocalcemia was demonstrated by the decrease in PTH levels, as well as the need for and duration of intravenous calcium supplementation.

Parathyroid vascular anatomy using intraoperative mapping angiography: the PARATLAS study

BACKGROUND

Understanding vascular anatomy of the parathyroid glands (PG) is crucial during thyroidectomy. The aim of this study was to describe patterns and distribution of parathyroid vessels.

METHOD

An analysis of all intraoperative mapping angiographies from indocyanine green injection and fluorescence imaging in patients undergoing thyroid surgery between February 2020 and September 2021. The parathyroid vessels were classified according to the pattern of contact with the thyroid. Data collection and analysis were carried out in accordance with MR004 reference methodology.

RESULTS

A total of 200 angiographies from 196 patients were analysed (159 female/37 male, mean(s.d.) age: 54.2 ± 13.7 years), and 320 PGs were assessed. The parathyroid vessels had no contact with the thyroid in 20 (6%; Type 0), a single-point of contact in 74 (23%; Type 1), a posterior path in 47 (15%; Type 2), a lateral path in 68 (21%; Type 3), an intrathyroidal path in 19 (6%; Type 4), and a possible medial path in 26 (8%; Type X1) cases. The course of the vessels was unclear in 36 cases (11%; Type X2). Spatial distribution analysis showed a concentration of superior parathyroid vessels around Zuckerkandl's tubercle, whereas the distribution of the inferior parathyroid vessels was anterior and sparse.

CONCLUSION

Intraoperative mapping angiographies help to define the main patterns of the parathyroid vessels according to their contact with the thyroid and provide surgically useful information about spatial vessel distribution.

Thyroidectomy and Its Complications: A Comprehensive Analysis

Background/Objectives: This study aims to assess the rate of complications in patients who underwent thyroid surgery and were monitored post-operatively to explore potential correlations between various parameters that may aid in clinical decision making. Methods: An observational retrospective study was conducted on patients who underwent thyroid surgery and were followed up in our Endocrinology Unit. Patients were selected based on strict criteria. The following data were collected: sex; age; type of thyroid disease; pre-operative symptoms due to thyroid pathology; surgical procedures; post-operative complications; histopathological diagnosis; and post-operative blood levels of TSH, PTH, vitamin D, and calcium. Results: Among 340 patients, 25.29% had benign thyroid disease. Total thyroidectomy was performed in 89.4% of cases. Recurrent laryngeal nerve injury was found in 32 patients. Hypocalcemia occurred in 14 patients within 24 h post-operatively. Histopathological examination identified incidental parathyroid tissue in 5.88% of thyroidectomy specimens. Post-operative hypoparathyroidism was observed in 26 patients, and vitamin D deficiency in 68 patients. Conclusions: The study demonstrated that thyroid surgery is quite a safe procedure; however, complications may occur. A statistically significant correlation was found between the type of surgery and the risk of vocal fold palsy, without correlation with the type of thyroid disease. A thorough pre-operative evaluation by a multidisciplinary team may help reduce the risk of post-operative complications. Despite the extensive knowledge of thyroid surgery, small refinements may further improve surgical outcomes.

Intraoperative strategies in identification and functional protection of parathyroid glands for patients with thyroidectomy: a systematic review and network meta-analysis

BACKGROUND

This study aimed to assess the benefits and limitations of four intraoperative visualization of parathyroid gland (IVPG) strategies in the identification and functional protection of parathyroid glands (PGs).

METHODS

We searched PubMed, the Cochrane Central Register of Controlled Trials, CNKI, EMBASE, Web of Science and Google Scholar databases until 30 June 2023. Four IVPG strategies were composed of the naked eyes (NE) and three imaging strategies: autofluorescence (AF), indocyanine green fluorescence (ICGF), and carbon nanoparticles (CN). We performed a pairwise meta-analysis (PMA) for direct comparisons and a Bayesian network meta-analysis (NMA) for indirect comparisons.

RESULTS

A total of 29 eligible studies were included. According to NMA and PMA, AF had significantly lower rates of postoperative hypocalcemia and hypoparathyroidism, PG inadvertent resection, and PG auto-transplantation compared to NE, while had significantly higher rate of PG identification. CN showed significantly lower rates of postoperative hypocalcemia and hypoparathyroidism, and PG inadvertent resection compared to NE in PMA and NMA. ICGF showed a significantly higher rate of PG auto-transplantation compared to NE in PMA and AF in NMA. According to SUCRA values, AF showed the best advantage in reducing the rate of postoperative hypocalcemia (0.85) and PG inadvertent resection (0.89), and increasing the rate of PG identification (0.80). CN had the greatest advantage in reducing the rate of postoperative hypoparathyroidism (0.95). ICGF ranked the highest in the rate of PG auto-transplantation (0.98).

CONCLUSIONS

Three imaging strategies demonstrate significant superiority over NE in the intraoperative PG identification and functional protection. AF is the best strategy in reducing the incidence of postoperative hypocalcemia, increasing the rate of PG identification, and reducing the rate of PG inadvertent resection and auto-transplantation. ICGF has great value in assessing PG viability, leading to the trend towards PG auto-transplantation. CN is the best strategy in reducing the incidence of postoperative hypoparathyroidism.

[First experience of applying domestic video fluorescent equipment for visualization and blood flow evaluation of the parathyroid glands]

In recent years, predictive methods for assessing the preservation of the parathyroid glands have been actively implemented. The article describes the first experience of evaluating the blood supply of the parathyroid glands by quantitative determination of the indocyanine green (ICG) accumulation index in real time in 6 patients before and after a thyroidectomy with central neck lymph node dissection for papillary thyroid cancer. Intraoperative fluorescent angiography was performed by using domestic equipment with a fluorescent module, as well as by using a domestic medication of ICG. Intraoperative values of the ICG accumulation index were compared with the levels of ionized calcium and parathyroid hormone perioperatively. No clinical manifestations of hypocalcemia were detected in the postoperative period. The obtained results showed the informativeness of the numerical assessment of the intensity of ICG fluorescence. The evaluation of the distribution (accumulation) of ICG has prospects for practical application in thyroid surgery in the formation of tactics for preserving the parathyroid glands and predicting postoperative hypoparathyreosis.

Prevention of hypocalcemia and hypoparathyroidism after total thyroidectomy. Recommendations of the Francophone Association of Endocrine Surgery (AFCE) with the French Society of Endocrinology (SFE) and the French Society of Nuclear Medicine (SFMN)

Postoperative hypoparathyroidism, resulting from removal and/or devascularization of one or more parathyroid glands, is a feared complication of total thyroidectomy. Two forms, which are distinguished by their frequency, their time to onset and their duration as well as by their presentation, must be individualized: early postoperative hypocalcemia, often secondary to early hypoparathyroidism is a frequent and often transient situation occurring within the first days after surgery; permanent hypoparathyroidism, which is rarer, manifests when parathyroid function remains impaired for more than six months after surgery. Because of their severity, these conditions must be known and ideally prevented during total thyroidectomy. The objective of this article is to provide surgeons with practical recommendations for the prevention, diagnosis, and treatment of hypoparathyroidism after total thyroidectomy. These recommendations, which are the fruit of a medico-surgical consensus, were developed by the Francophone Association of Endocrine Surgery (AFCE), the French Society of Endocrinology (SFE) and the French Society of Nuclear Medicine and Molecular Imaging. (SFMN). The content, grade and level of evidence for each recommendation was decided after consultation within a panel of experts, based on an analysis of recent literature.

The magic mirror: a novel intraoperative monitoring method for parathyroid glands

The accurate detection of parathyroid glands (PGs) during surgery is of great significance in thyroidectomy and parathyroidectomy, which protects the function of normal PGs to prevent postoperative hypoparathyroidism and the thorough removal of parathyroid lesions. Existing conventional imaging techniques have certain limitations in the real-time exploration of PGs. In recent years, a new, real-time, and non-invasive imaging system known as the near-infrared autofluorescence (NIRAF) imaging system has been developed to detect PGs. Several studies have confirmed that this system has a high parathyroid recognition rate and can reduce the occurrence of transient hypoparathyroidism after surgery. The NIRAF imaging system, like a magic mirror, can monitor the PGs during surgery in real time, thus providing great support for surgeries. In addition, the NIRAF imaging system can evaluate the blood supply of PGs by utilizing indocyanine green (ICG) to guide surgical strategies. The NIRAF imaging system and ICG complement each other to protect normal parathyroid function and reduce postoperative complications. This article reviews the effectiveness of the NIRAF imaging system in thyroidectomies and parathyroidectomies and briefly discusses some existing problems and prospects for the future.

Assessing Intraoperative Laser Speckle Contrast Imaging of Parathyroid Glands in Relation to Total Thyroidectomy Patient Outcomes

Background: Accurate assessment of parathyroid gland vascularity is important during thyroidectomy to preserve the function of parathyroid glands and to prevent postoperative hypocalcemia. Laser speckle contrast imaging (LSCI) has been shown to be accurate in detecting differences in parathyroid vascularity. In this surgeon-blinded prognostic study, we evaluate the relationship between intraoperative LSCI measurements and postoperative outcomes of total thyroidectomy patients. Methods: Seventy-two thyroidectomy patients were included in this study. After thyroid resection, an LSCI device was used to image all parathyroid glands identified, and a speckle contrast value was calculated for each. An average value was calculated for each patient, and the data were grouped according to whether the patient had normal (16-77 pg/mL) or low levels of parathyroid hormone (PTH) measured on postoperative day 1 (POD1). The aim of this study was to establish a speckle contrast threshold for classifying a parathyroid gland as adequately perfused and to determine how many such glands are required for normal postoperative parathyroid function. Results: A speckle contrast limit of 0.186 separated the normoparathyroid and hypoparathyroid groups with 87.5% sensitivity and 84.4% specificity: 7 of 8 patients with low PTH on POD1 had an average parathyroid speckle contrast above this limit, while 54 of 64 patients with normal postoperative PTH had an average parathyroid speckle contrast below this limit. Taking this value as the threshold for adequate parathyroid perfusion, it was determined that only one vascularized gland was needed for normal postoperative parathyroid function: 64 of 69 patients (92.8%) with at least one vascularized gland (determined by LSCI) had normal postoperative PTH, while all 3 patients (100%) with no vascularized glands had low postoperative PTH. Overall, the rates of temporary and permanent hypoparathyroidism in this study were 8.3% and 1.4%, respectively. Conclusions: LSCI is a promising technique for assessing parathyroid gland vascularity. It has the potential to help reduce the incidence of hypocalcemia after thyroidectomy by providing surgeons with additional information during surgery to aid in the preservation of parathyroid function.

In Situ Preservation of Parathyroid Gland With Vasculature for Papillary Thyroid Carcinoma Is Associated With Higher PTH Levels After Total Thyroidectomy

PURPOSE

To evaluate the impact of parathyroid gland vasculature preservation in-situ technique (PGVPIST) on postoperative parathyroid hormone (PTH) and calcium plasma levels in thyroid patients undergoing total thyroidectomy for papillary thyroid carcinoma (PTC).

STUDY DESIGN

Retrospective cohort study.

METHODS

Patients with PTC who underwent total thyroidectomy by either the conventional technique (group 1, January 2019 to January 2020) or PGVPIST (group 2, January 2020 to January 2021) were compared. Postoperative blood calcium levels and PTH levels were assessed in these groups.

RESULTS

Totally 149 patients with consecutive PTC underwent total thyroidectomy, including 60 patients in group 1 and 89 patients in group 2. Postoperative serum calcium levels in group 1 were insignificantly lower than in group 2 at day 1 (2.18 ± 0.02 vs 2.15 ± 0.01 mmol/L) and day 30 (2.27 ± 0.02 vs 2.38 ± 0.11) after surgery. But postoperative serum PTH levels in group 1 were significantly lower than that in group 2 at day 1 (23.68 ± 2.54 vs 31.46 ± 2.11 pg/mL) and day 30 (45.63 ± 3.21 vs 55.65 ± 2.89 pg/mL) after surgery.

CONCLUSION

Parathyroid gland vasculature preservation in-situ technique for PTC is associated with higher PTH level after total thyroidectomy. The parathyroid gland vasculature mostly strongly adheres with adjacent thyroid parenchyma. Therefore, deferred processing of tiny thyroid parenchyma of parathyroid gland vessels is essential to prevent devascularization.

Intraoperative Nerve Monitoring in Thyroidectomies for Malignancy: Does it Matter?

BACKGROUND

Recurrent laryngeal nerve (RLN) injury and postoperative hypocalcemia are potential complications of thyroidectomy, particularly in malignancy. Intraoperative nerve monitoring (IONM) remains controversial. We sought to evaluate the impact of IONM on these complications using a national data set.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program thyroidectomy-targeted data set was queried for patients who underwent thyroidectomies from 2016 to 2017. Patients were grouped according to IONM use. Logistic regression models were constructed to evaluate associations of variables with 30-day hypocalcemic events (HCEs) and RLN injury. Associations were expressed as odds ratios (ORs) with 95% confidence intervals (95% CIs). A subgroup analysis was performed of patients with malignancy.

RESULTS

A total of 9527 patients were identified; 5969 (62.7%) underwent thyroidectomy with IONM and 3558 (37.3%) without. By multivariable analysis, IONM had protective associations with HCE (OR = .81, 95% CI = .68-.96; P = .013) and RLN injury (OR = .83, 95% CI = .69-.98; P = .033). Malignancy increased risk of HCE (OR = 1.21, 95% CI=1.01-1.45; P = .038) and RLN injury (OR = 1.22, 95% CI = 1.02-1.46; P = .034). A large proportion (5943/9527, 62.4%) of patients had malignancy; 3646 (61.3%) underwent thyroidectomy with IONM and 2297 (38.7%) without. In the subgroup analysis, IONM had stronger protective associations with HCE (OR = .73, 95% CI = .60-.90; P = .003) and RLN injury (OR = .76, 95% CI = .62-.94; P = .012).

DISCUSSION

Malignancy was associated with increased risk of HCE and RLN injury. Intraoperative nerve monitoring had a protective association with HCE and RLN injury, both overall, and in the malignant subgroup. Intraoperative nerve monitoring was correlated with improved thyroidectomy outcomes, especially if the indication was malignancy. This warrants further study to clarify cause and effect.

Minimally invasive video-assisted thyroidectomy and transoral video-assisted thyroidectomy: A comparison of two systematic reviews

Background:

We compared two systematic reviews, one focusing on transoral video-assisted thyroidectomy (TOVAT) and the other on minimally invasive video-assisted thyroidectomy (MIVAT), to highlight the pros and cons that can determine the choice of one or the other procedure.

Materials and Methods:

PubMed, Scopus and ISI Web of Science databases were searched for relevant articles published from 2000 to June 2018. Both searches were performed using the same keywords. All articles describing human surgical case series of any size were included, while the following were excluded: articles published in languages other than English, case reports, reviews, early cadaver and animal studies and old reports of cases now included in more recent works. Application of the above selection criteria yielded 151 articles on TOVAT and 246 on MIVAT. Of these, 34 articles were selected for inclusion in the present study: 17 for the TOVAT group and 17 for the MIVAT group. The comparison was made considering the most common variables used in evaluating thyroid surgery procedures. The statistical methods used were Cohen's delta, Student's t-test and the non-parametric Mann–Whitney U-test.

Results:

The variable 'operative time' was found to show a very large effect size, and 'hospital stay' also differed significantly between the MIVAT and TOVAT groups.

Conclusions:

TOVAT and MIVAT should not be considered in competition with each other, but seen simply as alternative choices. Both appear to be safe methods, comparable in terms of post-operative complications, although the main reason for using TOVAT seems to be purely aesthetic.

Truncal vs Branch Ligation of Inferior Thyroid Arteries in Total Thyroidectomy: Does It Affect Postoperative Hypoparathyroidism?

OBJECTIVE

Postthyroidectomy hypoparathyroidism remains a significant challenge. Truncal ligation of the inferior thyroid arteries (ITAs) may lead to an increased risk of hypoparathyroidism; however, dissection along the thyroid capsule with branch ligation of the thyroid arteries could be a safer option. This study's objective was to compare the effect of truncal versus branch ligation of the ITAs on the rate of postoperative hypoparathyroidism.

STUDY DESIGN

Randomized prospective trial in line with the CONSORT guidelines.

SETTING

The study was conducted at a high-volume tertiary care setting.

METHODS

We randomized 319 patients into 2 groups: truncal ITA ligation (n = 157) and branch ITA ligation (n = 162). The primary outcomes were serum calcium and parathormone levels on the second postoperative day, followed by the levels on months 1, 3, 6, and 12. The need for exogenous replacements was noted. The secondary outcomes, such as operative time, blood loss, and other complications, were also recorded.

RESULTS

Our study revealed a significant difference in the incidence of transient hypocalcemia in patients undergoing truncal ITA ligation and branch ITA ligation (22.9% vs 3.1%, P < .05). The results showed that the levels of serum calcium and parathormone dropped on the second postoperative day and that 36 patients from the truncal ITA ligation group required exogenous calcium and vitamin D replacement. In contrast, only 5 patients from the branch ITA ligation group required the same.

CONCLUSIONS

This is the largest randomized trial of patients undergoing thyroidectomy, and it shows that dissection along the thyroid capsule with branch ligation of the ITAs is more likely to preserve parathyroid function as opposed to truncal ligation of ITAs.

Methodological Quality of Systematic Reviews and Meta-analyses Published in High-Impact Otolaryngology Journals

OBJECTIVE

To assess the methodological quality of intervention-focused systematic reviews (SRs) and meta-analyses (MAs) published in high-impact otolaryngology journals.

DATA SOURCES

Ovid Medline, Embase, and Cochrane Library.

REVIEW METHODS

A comprehensive search was performed for SR and MA citations from 2012 to 2017 in the 10 highest impact factor otolaryngology journals. Abstracts were screened to identify published manuscripts in which the authors indicated clearly that they were performing an SR or MA. Applying a modified typology of reviews, 4 reviewers characterized the review type as SR, MA, or another review type. A simplified version of the AMSTAR 2 (A MeaSurement Tool to Assess systematic Reviews 2) tool was used to assess the reporting and methodological quality of the SRs and MAs that were focused on interventions.

RESULTS

Search and abstract screening generated 499 manuscripts that identified themselves as performing an SR or MA. A substantial number (85/499, 17%) were review types other than SRs or MAs, including 34 (7%) that were literature reviews. In total, 236 SRs and MAs focused on interventions. Over 50% of these SRs and MAs had weaknesses in at least 3 of the 16 items in the AMSTAR 2, and over 40% had weaknesses in at least 2 of the 7 critical domains. Ninety-nine percent of SRs and MAs provided critically low confidence in the results of the reviews.

CONCLUSION

Intervention-focused SRs and MAs published in high-impact otolaryngology journals have important methodological limitations that diminish confidence in the results of these reviews.

Incidental thyroid carcinomas. A retrospective study

AIM

The aim of the present study is to report our series of incidental thyroid carcinomas in the last 15 years and their follow-up, discussing therapeutics indications and surgical choices.

PATIENTS AND METHODS

We have considered 1793 patients operated on Surgical Sciences Department of "Sapienza" University of Rome from January 1, 2001 to December 31, 2015. The study was conducted on 83 totally thyroidectomized patients with a real incidental thyroid carcinoma, by clinical, laboratory and instrumental controls. Whole-body scan was the most important test in postoperative evaluation.

RESULTS

In our series, the incidence of incidental carcinomas was 4.62%. Compared to the total number of cancer patients, the percentage is 21,9%. In 15.66% of cases there was multifocality and in 7.23% also bilaterality. Regarding the histological type, in all cases they were papillary carcinoma. The size of the neoplastic lesions ranged from a minimum of 3 to a maximum of 10 mm. Whole-body scan revealed lymph node metastasis in 57.69% of patients.

DISCUSSION

Comparing these data with our previous studies we have seen a significant increase in incidence of incidental thyroid carcinomas over the years. Our therapeutical choice is total thyroidectomy and complection thyroidectomy after lobectomy, because of a relevant percentage of multifocality and/or bilaterality of these tumors. Many Authors on the contrary prefer a more conservative approach invoking the good prognosis of these tumors. The 57.69% of lymph node metastasis at postoperative whole-body scan comfort us in our setting.

CONCLUSION

Incidental thyroid carcinomas are not uncommon. We consider only tumors until 1 cm in diameter. Multifocality and bilaterality are often present such as occult lymph node metastasis. Our therapeutical choice is total thyroidectomy in order to conduct a proper follow-up.