Symptomatic benign thyroid diseases are common, and multinodular goiter with concomitant iodine deficiency is the most frequent presentation requiring surgical intervention worldwide. Surgery provides definitive treatment and is the treatment of choice. All surgical options, most commonly total or near-total thyroidectomy, are used to rule out malignancy in a benign-appearing thyroid. However, surgery has some inherent risks, including recurrent hypocalcemia, voice dysfunction, and recurrent laryngeal nerve injury.
Voice dysfunction and hypocalcemia are the most common complications after thyroidectomy. It may result from direct or indirect injury to the recurrent laryngeal nerve leading to transient or permanent vocal cord paralysis. Indirect nerve injury is reported to be more common than direct nerve injury. It is postulated that after total thyroidectomy, the strap muscles exclusively bear the laryngotracheal unit and are the basis of voice dysfunction. Symptomatic hypocalcemia is the most frequent complication after total thyroidectomy and occurs in up to 50% of cases. Hypocalcemia results from loss of the parathyroid glands, and patients with this condition require supplements such as calcium or vitamin D3 (cholecalciferol) to recover function.
Various methods have been evaluated to prevent these complications. The use of steroids (ie, dexamethasone) in the perioperative period has been shown to improve voice function postoperatively. Intraoperative neural monitors have also been used to prevent this complication.
Authors Adeel Dhahri et al hypothesized that the use of a single preoperative injection of dexamethasone could reduce postoperative voice dysfunction and hypocalcemia. They conducted a double-blind controlled trial to assess the effect of preoperative dexamethasone on vocal dysfunction and hypocalcemia after thyroidectomy.
This double-blind, parallel-group, placebo-controlled randomized clinical trial was conducted from January 15, 2014, to December 31, 2019, at the Department of Surgery, Holy Family Hospital in Rawalpindi, Pakistan. All patients with a benign thyroid condition and no preoperative corrected hypocalcemia and voice or vocal quality dysfunction were included. Patients were excluded if they had previous thyroid or neck surgery, known vocal cord dysfunction on laryngoscopy, hearing or voice problems, a history of gastroesophageal reflux, stomach ulcer disease, or contraindications to steroid use.
Corrected serum calcium levels and Voice Analog Score were defined and measured preoperatively. The dexamethasone group received a 2-mL intravenous dose of 8 mg of dexamethasone 60 minutes before the induction of anesthesia. In contrast, the placebo group received 2 mL of intravenous normal saline (0.9%) 60 minutes before the induction of anesthesia. Main outcome included Evidence of hypocalcemia and voice dysfunction. Voice dysfunction was defined as a subjective score of less than 50 on a Voice Analog Score scale of 0 to 100 points.
- A total of 192 patients (mean [SD] age, 38.9 [12.4] years; 156 women [81.2%]) were included in the study, with 96 patients randomized to each study group (dexamethasone group; placebo group).
- In the first 24 hours after undergoing thyroidectomy, 47 patients (24.4%) developed hypocalcemia and 18 (9.4%) were symptomatic.
- At 3 days postthyroidectomy, 4 of 96 patients (4.2%) in the placebo group had hypocalcemia compared with no patients in the dexamethasone group.
- At 24 hours postthyroidectomy, 8 of 96 patients (8.3%) in the dexamethasone group had voice dysfunction compared with 32 of 96 patients (33.3%) in the placebo group.
- A total of 40 patients (20.8%) reported voice dysfunction. The absolute reduction in the rate of hypocalcemia at 24 hours was 24% (95% CI, 11.9%-35.2%) and at 3 days was 4.2% (–0.44% to 10.0%).
- The rate of symptomatic hypocalcemia was 19% lower in the dexamethasone group than in the placebo group (95% CI, 11.1%-27.7%).
- The rate of voice dysfunction was 25% lower in the dexamethasone group than in the placebo group (95% CI, 13.7%-35.7%).
In this RCT, patients who received dexamethasone before thyroidectomy had a lower rate of hypocalcemia in the first 24 hours after surgery than those who received a placebo. Additionally, only 4 patients (2.1%) had hypocalcemia on the third day after surgery. This study also confirmed the efficacy of intraoperative dexamethasone for avoiding vocal nerve palsy, with a significantly lower voice dysfunction rate seen during the first 24 hours after surgery. Thus, a single preoperative 8-mg dose of dexamethasone was safe and effective in reducing transient postoperative hypocalcemia and ameliorating postthyroidectomy voice dysfunction.
Total thyroidectomy is considered a safe surgical procedure for benign thyroid diseases, such as Graves disease ormultinodular goiter, with only a slight risk of complications. Temporary hypocalcemia and postthyroidectomy voice dysfunction are 2 of the few frequently encountered complications. Dexamethasone is a corticosteroid and has a well-established immune-modulating effect at the surgical site; it reduces inflammation, edema, and physiological stress.
This RCT demonstrated that a single 8-mg dose of dexamethasone during the preoperative period was safe and effective in improving transient, immediate postoperative hypocalcemia as well as temporary voice dysfunction in patients undergoing thyroidectomy.