Predictors and risk factors of hypoparathyroidism after total thyroidectomy

The PGRIS and parathyroid splinting concepts for the analysis and prognosis of protracted hypoparathyroidism

Most patients with hypocalcemia after total thyroidectomy will recover the parathyroid function in a few weeks, but some 20-30% of them will still be in the need for replacement therapy one month after surgery and about 5-10% of those will develop permanent hypoparathyroidism. Although postoperative hypocalcemia has been related to several demographic and metabolic causes, parathyroid hormone (PTH) decline, resulting from autotransplantation, inadvertent excision or devascularization of the parathyroid glands, is the common final pathway. The number of parathyroid glands remaining in situ (PGRIS) is a key variable to understand the pathogenesis of protracted hypoparathyroidism and the chances for restoration of the parathyroid function. Normal-high serum calcium concentration, probably achieved by a more intensive medical treatment at the time of hospital discharge, has been identified as an independent variable favoring recovery of the parathyroid function. This we refer to as parathyroid splinting, a hypothesis holding that putting the injured parathyroid parenchyma at rest after thyroidectomy may improve long-term outcome of protracted hypoparathyroidism.

Risk factors of hypoparathyroidism following total thyroidectomy with central lymph node dissection

The risk factors of hypoparathyroidism after total thyroidectomy (TT) with central lymph node dissection (CND) have not been completely defined. The aim of the study was to evaluate the risk factors of hypoparathyroidism after the surgery.We retrospectively reviewed our patients who underwent TT and CND (including lateral lymph node dissection) for thyroid carcinoma between January 2013 and June 2016. According to the postoperative serum levels of parathyroid hormone within 6 months, the patients were divided into normal, transient hypoparathyroidism, and permanent hypoparathyroidism groups. The clinicopathologic characteristics and surgical details were compared among the 3 groups. The risk factors of hypoparathyroidism were investigated by univariate and multivariate analyses.Of the 903 patients, 399 (44.2%) were found to have transient hypoparathyroidism and 10 (1.1%) had permanent hypoparathyroidism. On multivariate analysis, female gender (P < .001), nonuse of carbon nanoparticles (P = .038), parathyroid autotransplantation (P < .001), accidental parathyroid resection (P = .004), and bilateral CND (BCND, P = .003) were the independent risk factors of transient hypoparathyroidism; nonuse of carbon nanoparticles (P = .041) and a tumor in the upper pole of thyroid gland (P = .031) were the independent risk factors of permanent hypoparathyroidism. Patients with transient hypoparathyroidism were more likely to develop permanent hypoparathyroidism when they had hypertension (P = .026) and a tumor in the upper pole of thyroid gland (P = .010).Precise surgical techniques and carbon nanoparticles suspension should be applied for in situ preservation of parathyroid glands (PGs) in thyroid carcinoma patients, especially in females with hypertension and a tumor in the upper pole of thyroid gland. Autotransplantation is only performed when a PG is resected inadvertently or devascularized. TT with BCND should be better performed by an experienced surgeon to reduce the incidence of hypoparathyroidism.

Hypoparathyroidism

Hypoparathyroidism is a disease characterized by inadequately low circulating concentrations of parathyroid hormone (PTH) resulting in low calcium levels and increased phosphate levels in the blood. Symptoms of the disease result from increased neuromuscular irritability caused by hypocalcaemia and include tingling, muscle cramps and seizures. The most common cause of the disease is inadvertent removal of, or injury to, the parathyroid glands during neck surgery, followed by genetic, idiopathic and autoimmune aetiologies. Conventional treatment includes activated vitamin D and/or calcium supplements, but this treatment does not fully replace the functions of PTH and can lead to short-term problems (such as hypocalcaemia, hypercalcaemia and increased urinary calcium excretion) and long-term complications (which include nephrocalcinosis, kidney stones and brain calcifications). PTH replacement has emerged as a new treatment option. Clinical trials using human PTH(1-34) and PTH(1-84) showed that this treatment was safe and effective in studies lasting up to 6 years. Recombinant human PTH(1-84) has been approved in the United States and Europe for the management of hypoparathyroidism; however, its effect on long-term complications is still being evaluated. Clinical practice guidelines, which describe the consensus of experts in the field, have been published and recognize the need for more research to optimize care. In this Primer, we summarize current knowledge of the prevalence, pathophysiology, clinical presentation and management of hypoparathyroidism.

Is Outpatient Thyroid Surgery for Everyone?

Thyroidectomy is a common surgical procedure. Traditionally, surgeons have performed thyroidectomy on an inpatient basis. However, consistent with current trends in surgery, some practices are transitioning thyroidectomy to an outpatient setting. Although concerns for hypocalcemia and postoperative bleeding exist regardless of surgeon experience, multiple studies demonstrate that outpatient thyroidectomy is safe in the hands of high-volume surgeons. Indeed, experienced thyroid surgeons who perform thyroidectomy in an outpatient setting experience excellent patient outcomes and reduced costs. However, outpatient thyroidectomy may not be suitable for all surgeons, hospitals, or patients. When evaluating whether to implement an outpatient thyroid program, a practice should consider a number of important factors including the team performing the procedure, the hospital, and the patient. With the appropriate staff education and experience, hospital setting, and patient selection, practices in a multitude of settings can successfully develop a safe, cost-effective outpatient thyroid program.

Risk factors for postoperative hypocalcemia

Hypocalcaemia is one of the most common complications after thyroidectomy; however, it is still unclear what preoperative factors could predict this event. The aim of this study was to evaluate the role of risk factors for hypocalcaemia after total thyroidectomy (TT). Consecutive patients who underwent total thyroidectomyat our institution between January 2014 and January 2016 were enrolled. The clinical and pathologic characteristics and surgical details of normocalcemic and hypocalcemic patients were compared. Univariate and multivariate analyses to estimate risk ratio were assessed. A total of 328 patients underwent TT; histology revealed benign and malignant disease in 83 and 17% of cases, respectively. Central-compartment neck dissection (CCND) was performed in 36 subjects (10.9%). Parathyroid glands were observed in 23% (76) of specimens. Laboratory asymptomatic hypocalcaemia was observed in 92 (28%) patients; symptomatic hypocalcaemia occurred in 26 (7.9%). Transient hypocalcaemia has been observed in 48 (14.6%) patients; permanent hypocalcaemia occurred in two subjects (0.6%). On univariate analysis, malignant pathology (p < 0.001), CCND (p < 0.05), female gender (p < 0.001), presence of at least two parathyroid glands in specimens (p < 0.002), and operative time longer than 120 min (p < 0.05) were factors that significantly increased the risk of developing asymptomatic and transient hypocalcaemia. After logistic regression analysis, malignant pathology (p < 0.000; p < 0.001) and CCND (p < 0.005; p = 0.013) were the significant factors that affected the development of symptomatic and transient hypocalcaemia. The presence of malignant pathology and CCND was found to be significant risks factors for postoperative hypocalcaemia. In patients in whom this pathological features are present, attention should be paid to rapidly start an adequate therapy.