Intraoperative near-infrared autofluorescence imaging for hypocalcemia risk reduction after total thyroidectomy: Evidence from a meta-analysis

Long-term kidney outcomes in patients with permanent hypoparathyroidism after total thyroidectomy for benign disease: A population-based study

BACKGROUND

Permanent hypoparathyroidism is a significant complication after total thyroidectomy. This study aimed to evaluate the long-term impact of postoperative permanent hypoparathyroidism on kidney outcomes.

METHODS

Data of patients undergoing total thyroidectomy from 1999 to 2014 were retrieved. The estimated glomerular filtration rate was determined from serum creatinine results. Permanent hypoparathyroidism was defined as requiring oral calcium and vitamin D supplements postoperatively for at least 6 months. The primary outcome was a sustained decline in the estimated glomerular filtration rate from baseline by ≥50%. Secondary outcomes were end-stage kidney disease (a composite of sustained estimated glomerular filtration rate <15 mL/min/1.73 m2, need for dialysis, and kidney transplantation) and rate of estimated glomerular filtration rate decline. Patients with and without permanent hypoparathyroidism were compared. Multivariable Cox regression analysis was performed to identify independent risk factors for sustained estimated glomerular filtration rate decline by ≥50%.

RESULTS

In total, 3,245 patients were eligible for analysis; 418 patients (12.9%) had permanent hypoparathyroidism. Upon median follow-up of 11.6 years, more patients with permanent hypoparathyroidism had a sustained decline in estimated glomerular filtration rate from baseline by ≥50% compared to those without (15.6% vs 6.9%, P < .001). Similar findings were obtained on Kaplan-Meier analysis (P < .001). Permanent hypoparathyroidism was an independent risk factor for sustained estimated glomerular filtration rate decline by ≥50% (adjusted hazard ratio 2.77, P < .001). Other risk factors included age, preoperative estimated glomerular filtration rate <60 mL/min/1.73m2, and diabetes mellitus. Patients with permanent hypoparathyroidism had a more rapid estimated glomerular filtration rate decline (-1.60 vs -0.70 mL/min/1.73 m2/year, difference -0.91 mL/min/1.73m2/year, P < .001).

CONCLUSION

Patients with postsurgical permanent hypoparathyroidism were at greater risk of renal impairment. Further research is warranted to improve the identification and preservation of parathyroid glands during thyroidectomy to minimize patient morbidity.

The impact of using near-infrared autofluorescence on parathyroid gland parameters and clinical outcomes during total thyroidectomy: a meta-analytic study of randomized controlled trials

BACKGROUND

The added benefit of using near-infrared autofluorescence (NIRAF) during total thyroidectomy (TT) remains controversial. This study investigated whether or not NIRAF results in improved patient outcomes postoperatively.

MATERIALS AND METHODS

We analyzed 1711 TT patients, reported in nine randomized controlled trials, following a systematic search of five databases. NIRAF was compared to the standard of care (naked eye with/without white light). Outcomes included parathyroid gland (PG) and calcium parameters and other clinical outcomes. For dichotomous outcomes, the log odds ratio (logOR) was calculated, and for continuous outcomes, the crude mean difference (MD) was measured. Sensitivity analysis was performed when heterogeneity was significant. The revised Cochrane risk of bias tool was used to assess the methodological quality.

RESULTS

Compared to the standard of care, the use of NIRAF was associated with a significant reduction in postoperative hypoparathyroidism [logOR=-0.31; 95% CI: -0.57: -0.05], inadvertent PG removal [logOR=-0.93; 95% CI: -1.60: -0.26], and postoperative hypocalcemia [logOR=-0.43 mmol/l; 95% CI: -0.77: -0.09]. It was also associated with significantly higher postoperative PTH levels [MD=4.78 pg/ml; 95% CI: 2.13: 7.43], PG identification rate [logOR=1.02; 95% CI: 0.31: 1.72], postoperative serum calcium [MD=0.05; 95% CI: 0.00: 0.09], and operative time [MD=9.38 min; 95% CI: 6.68: 12.09]. No difference was seen regarding PG autotransplantation, length of hospital stay, and hospitalization due to hypocalcemia. Seven trials had low risk and the remainder had some concerns.

CONCLUSION

NIRAF is superior to the naked eye in identifying all four PGs during TT. The reduced risk of postoperative hypoparathyroidism and hypocalcemia reflected this preservation value. However, it was not associated with a change in the length of hospital stay. Although rare, the readmission rate due to hypocalcemia was similar across both methods.

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.

Near-Infrared Autofluorescence Imaging in Thyroid Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

This meta-analysis aimed to assess the position of near-infrared autofluorescence (NIRAF) imaging in the recognition and protection of the parathyroid gland (PG) during thyroidectomy.

METHODS

The PubMed, MEDLINE, EMBASE, Web of Science, and Cochrane Library databases were searched up to June 2021. The primary outcome was to evaluate the rates of postoperative hypocalcemia, inadvertent PG resection, and autotransplantation of PG when adopting NIRAF imaging compared with standard naked-eye (N-E) surgery.

RESULTS

Eight studies with 2,889 patients were enrolled in the analysis. Our analysis showed that the incidence of transient hypocalcemia was 7.11% (60/844) in the NIRAF group and 22.40% (458/2045) in the N-E group (p < 0.0001) and the rate of transient hypoparathyroidism was 28.31% (126/445) and 33.36% (496/1487) in the NIRAF and N-E groups (p = 0.0008). The rate of inadvertent resection of PGs was 7.65% (55/719) in the NIRAF group and 14.39% (132/917) in the N-E group (p < 0.0001). No significant difference was observed in other indexes including the pooled proportion of permanent hypocalcemia and rate of PG autotransplantation.

CONCLUSIONS

The application of NIRAF imaging in thyroidectomy can help lower the incidence of inadvertent PG resection and reduce the risk of postoperative hypocalcemia and hypoparathyroidism compared with N-E recognition.

Preliminary experience with the EleVision IR system in detection of parathyroid glands autofluorescence and perfusion assessment with ICG

BACKGROUND

Postoperative hypoparathyroidism remains the most frequent complication of neck endocrine surgery. In order to reduce the incidence of this feared complication, several systems for imaging of near infrared autofluorescence (NIRAF) have been invented to help surgeons identify parathyroid glands (PTGs) and evaluate their vascularization. We evaluated the efficacy of the EleVision IR system in thyroid and parathyroid surgery.

METHODS

We used the EleVision IR system in 25 patients who underwent thyroid/parathyroid surgery or both at our institution between December 2020 and July 2021. At various stages of the surgery, the surgeon first looked for PTGs with the naked eye and then completed the visual inspection with NIRAF imaging. We then compared both the naked eye and NIRAF-supported PTGs detection rates. At the end of surgery, we performed indocyanine green angiography of PTGs in 17 patients.

RESULTS

In total, we identified 80% of PTGs: 65% with the naked eye only and additional 15% with the assistance of the EleVision IR system. 14 of 17 patients evaluated by ICG angiography had at least one well-vascularized PTG. Only one of these patients (a case of subtotal parathyroidectomy for tertiary hyperparathyroidism) developed symptomatic postoperative hypocalcemia despite a normal parathormone level. The three other patients had at least one remaining moderately-vascularized PTG and only one patient developed transient postoperative hypoparathyroidism.

CONCLUSION

We concluded that EleVision IR provides an efficient support for identification and evaluation of PTGs, and may be of great assistance in endocrine surgery. The images are easy to interpret even for less experienced surgeons thanks to the different types of color visualization and the possibility to measure the relative fluorescence intensity of PTGs and surrounding tissues.

The effectiveness and safety of prophylactic central neck dissection in clinically node-negative papillary thyroid carcinoma patients: A meta-analysis

OBJECTIVE

This meta-analysis was performed to evaluate the effectiveness and safety of prophylactic central neck dissection (PCND) in patients with clinically node-negative (cN0) papillary thyroid carcinoma.

MATERIALS AND METHODS

A meta-analysis of the literature was performed using the key words "papillary thyroid carcinomas" and "lymph node ecisions" for searches of electronic databases. Complications such as transient hypocalcemia, permanent hypocalcemia, transient and permanent hypoparathyroidism, transient and permanent vocal cord paralysis, transient recurrent and permanent recurrent laryngeal nerve injury, and local recurrence were pooled by meta-analysis. Stata17.0 was used to carry out the meta-analysis.

RESULTS

Data were extracted from 15 studies. In the present review, the group of patients who had total thyroidectomy (TT) with PCND had a lower local recurrence than the group with TT alone (OR 0.22, 95% CI 0.10-0.45, P = 0.000), whereas the incidence of permanent hypocalcemia (OR 4.24, 95% CI 1.05-17.22, P = 0.043) and transient hypoparathyroidism (OR 2.14, 95% CI 1.34-3.42, P =0.001) were higher. No significant differences were recorded in the incidence of other complications: transient hypocalcemia (OR 2.24, 95% CI 0.77-6.51, P = 0.138), permanent hypoparathyroidism (OR 1.70, 95% CI 0.89-3.27, P = 0.111), transient vocal cord paralysis (OR 1.48, 95% CI 0.78-2.83, P = 0.231), permanent vocal cord paralysis (OR 1.44, 95% CI 0.53-3.94, P = 0.477), transient recurrent laryngeal nerve injury (OR 1.47, 95% CI 0.93-2.32, P = 0.102) and permanent recurrent laryngeal nerve injury (OR 1.24, 95% CI 0.56-2.74, P = 0.587) between the two groups.

CONCLUSION

Compared with TT alone, TT with PCND was more effective in reducing local recurrence without increasing the risk of recurrent laryngeal nerve, thyroid and vocal cord, except for hypocalcemia and transient hypoparathyroidism. Therefore, we believe that TT with PCND should be recommended for patients with cN0 PTC.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD4202 2355078.

Thyroidectomy for Cancer: The Surgeon and the Parathyroid Glands Sparing

BACKGROUND

The diagnosis of thyroid cancer is continuously increasing and consequently the amount of thyroidectomy. Notwithstanding the actual surgical skill, postoperative hypoparathyroidism still represents its most frequent complication. The aims of the present study are to analyze the rate of postoperative hypoparathyroidism after thyroidectomy, performed for cancer by a single first operator, without any technological aid, and to compare the data to those obtained adopting the most recent technological adjuncts developed to reduce the postoperative hypoparathyroidism.

METHODS

During the period 1997-2020 at the Endocrine Surgery Unit of the Department of Clinical and Experimental Medicine of the University of Florence, 1648 consecutive extracapsular thyroidectomies for cancer (401 with central compartment node dissection) were performed. The percentage of hypoparathyroidism, temporary or permanent, was recorded both in the first period (Group A) and in the second, most recent period (Group B). Total thyroidectomies were compared either with those with central compartment dissection and lobectomies. Minimally invasive procedures (MIT, MIVAT, some transoral) were also compared with conventional. Fisher's exact and Chi-square tests were used for comparison of categorical variables. p < 0.01 was considered statistically significant. Furthermore, a literature research from PubMed^® has been performed, considering the most available tools to better identify parathyroid glands during thyroidectomy, in order to reduce the postoperative hypoparathyroidism. We grouped and analyzed them by technological affinity.

RESULTS

On the 1648 thyroidectomies enrolled for the study, the histotype was differentiated in 93.93 % of cases, medullary in 4% and poorly differentiated in the remaining 2.06%. Total extracapsular thyroidectomy and lobectomy were performed respectively in 95.45% and 4.55%. We recorded a total of 318 (19.29%) cases of hypocalcemia, with permanent hypoparathyroidism in 11 (0.66%). In regard to the literature, four categories of tools to facilitate the identification of the parathyroids were identified: (a) vital dye; (b) optical devices; (c) autofluorescence of parathyroids; and (d) autofluorescence enhanced by contrast media. Postoperative hypoparathyroidism had a variable range in the different groups.

CONCLUSIONS

Our data confirm that the incidence of post-surgical hypoparathyroidism is extremely low in the high volume centers. Its potential reduction adopting technological adjuncts is difficult to estimate, and their cost, together with complexity of application, do not allow immediate routine use. The trend towards increasingly unilateral surgery in thyroid carcinoma, as confirmed by our results in case of lobectomy, is expected to really contribute to a further reduction of postsurgical hypoparathyroidism.