[Hypoparathyroidism and hypocalcemia following thyroid surgery of multinodular goiter. Multivariant study of the risk factors]

Effectiveness of hemi-thyroidectomy in relieving compressive symptoms in cases with large multi nodular goiter

Introduction and importance

This case series describe the efficacy of hemi-thyroidectomy to relieve the compressive symptoms of cases having large multi-nodular goiter with preservation of the thyroid gland function. It's considered as an education tool for surgeons to perform safe hemi thyroidectomy to patients indicated for total removal of the gland. Compressive symptoms like mild/severe dysphagia or dyspnea associated with both benign and malignant thyroid disease. Although total thyroidectomy is currently considered the standard of care, hemi thyroidectomy is another surgical option with more benefits.

Case presentation

This case series was performed in a tertiary university hospital in Riyadh, Saudi Arabia. It included 35 females and 3 males above the age of 18 (mean age 42 years). All the operations were elective hemi-thyroidectomies performed by one surgeon, during 2019. Patients were complaining of; Voice Change, Neck Swelling, Dysphagia, Chocking, SOB, and Orthopnea. 20 of them were medically free and 18 patients had multiple associated comorbidities.

Clinical findings and investigations

Demographic data, baseline co-morbidities, TSH levels prior to surgery, thyroid gland size, FNA results and pre-operative symptoms were recorded. In addition, compressive symptomatology outcomes from two weeks to two years were recorded. Thirty-two of them (84%) had their symptoms resolve completely and did not need a completion surgery. Out of the 6 who had persistent symptoms, only two needed a completion surgery. Furthermore, only 34.2% required thyroid hormone replacement, 31.6% were euthyroid and 2.6% were hypothyroid preoperatively.

Interventions and outcome

Hemi thyroidectomy was chosen to avoid the risk of hormone replacement, and hypocalcemia. Our results revealed that compressive symptoms were effectively relieved in the majority of our patients. Only 2 patients had to undergo completion thyroidectomy due to compressive symptoms with no perioperative or postoperative complications.

Relevance and impact

We would recommend hemi thyroidectomy for cases of large multi nodular goiter due to its positive implication on patient outcome particularly if the patient refuse hormonal replacement.

•

Compressive symptoms were effectively relieved in the majority of our patients.

•

Only 2 patients had to undergo completion thyroidectomy due to compressive symptoms.

•

No perioperative or postoperative complications were witnessed during the primary or completion surgery.

•

The main drawback with hemithyroidectomy is recurrence.

•

Nevertheless, most recurrences post thyroid surgery are asymptomatic and are diagnosed on ultrasonography.

Perioperative kinetics of parathyroid hormone in unilateral, primary thyroid surgery

Dysfunction of the parathyroid glands is an important cause of complications after thyroid surgery. Intraoperative monitoring of the function of the parathyroid glands can be performed using parathyroid hormone (PTH) kinetics. Unilateral thyroid surgery is associated with a decreased risk for postoperative hypocalcemia (POH) and permanent hypoparathyroidism (PEH). We focused on unilateral thyroid surgery by monitoring the functionality of the parathyroid glands and comparing the perioperative PTH kinetics of patients with and without POH. In a prospective study, 143 patients scheduled for unilateral thyroid surgery underwent monitoring of perioperative changes in serum PTH and serum calcium levels, and of clinical symptoms of hypocalcemia. The rates of POH and PEH were 18.2 and 0%, respectively. In patients without POH, PTH significantly increased from the time of skin incision to the end of the operation and after the operation (20.1 pg/ml, IQR 15.5-26.8 vs. 21.4 pg/ml, IQR 16.4-29.5; p=0.005), which was not the case in patients who developed POH. In a multivariate analysis of predictive factors for POH, two parameters became significant, namely female gender (odds ratio 6.87, 95% confidence interval 0.92-51.01) and lower initial serum calcium levels (odds ratio 3.54*e(-8), 95% confidence interval 3.63*e(-12); 0.00). The rate of POH was unexpectedly high. Rather than intraoperative PTH declines, an unstable balance of factors that influence calcium metabolism likely is the major contributor to POH after unilateral thyroid surgery. There was no case of PEH after unilateral, primary thyroid surgery, which underlines the need for an individualized approach to the extent of resection.