Intraperitoneal Dexamethasone Spraying on Vagal Nerve-Rich Areas for Prevention of Hoarseness After Upper Abdominal Surgery

The mechanism of postoperative hoarseness remains unclear. It is traditionally attributed to direct injury to the recurrent laryngeal nerve or to endotracheal intubation. However, the surgical field in upper abdominal procedures is remote from the recurrent laryngeal nerve, yet the incidence of hoarseness is higher than in many other surgeries. Preclinical animal experiments by the research group have demonstrated that electrical or thermal stimulation of the subdiaphragmatic vagal nerve can induce vocal cord paralysis, and that immediate topical spraying of dexamethasone onto the affected area significantly reduces this effect. It is hypothesized that thermal injury to vagal nerve fibers in the upper abdomen triggers aberrant signaling through the solitary nucleus to the nucleus ambiguus, ultimately resulting in dysfunction of the recurrent laryngeal nerve.

This trial is designed as a single-center, prospective, randomized, double-blind, placebo-controlled study. A total of 584 adult patients scheduled for elective gastric, hepatobiliary, or pancreaticoduodenal surgery will be enrolled. At the end of the main surgical procedure and before abdominal closure, the surgeon will spray 10 mg of dexamethasone onto the vagal nerve-rich areas, such as the peritoneum around the esophageal hiatus, the lesser omental sac, and the surface of the hepatoduodenal ligament.

Voice assessments will be conducted daily from postoperative day 1 through day 10 using the GRBAS scale by a trained evaluator blinded to group assignment. Patients will also undergo voice acoustic recording for Praat analysis. Those in the placebo group who develop hoarseness will be re-randomized to receive either intravenous dexamethasone 5 mg or placebo daily for 3 days.

Inclusion criteria

• Age 18 to 75 years, both sexes.
• Elective abdominal surgery (including gastric, hepatobiliary, and pancreaticoduodenal surgery) under general anesthesia.
• American Society of Anesthesiologists (ASA) physical status classification I-III.
• Preoperative GRBAS Grade (G) score = 0 (no hoarseness).
• Signed written informed consent.

Exclusion criteria

• Need for systemic glucocorticoid therapy during hospitalization for other reasons.
• Pre-existing hoarseness, vocal cord paralysis, or organic vocal cord lesions.
• History of neck surgery, neck radiotherapy, or laryngeal surgery.
• Known allergy to dexamethasone or other glucocorticoids.
• Active peptic ulcer or gastrointestinal bleeding within 6 months prior to enrollment.
• Uncontrolled diabetes mellitus or severe active infection.