Retrospective Evaluation of Hemithyroidectomy in 14 Horses

Abstract

The clinical findings of thyroid neoplasia in horses are not associated with the diagnosis of malignancy. Complete surgical resection of the abnormal lobe prevents local recurrence of neoplastic thyroid tissue. The modified hemithyroidectomy technique preserves the function of the recurrent laryngeal nerve.

Standing thyroidectomy in 10 horses

“…RLNN has been reported as a complication in up to 50% of cases undergoing hemithyroidectomy under GA . In a more recent study, there were no complications associated with the recurrent laryngeal nerve ipsilateral to the thyroidectomy . In the current report, none of the horses developed RLNN.…”

“…Hemorrhage has been reported as a possible intraoperative complication when removing large thyroid tumors . The thyroid gland has a blood supply of 4‐6 mL/min/g and it is therefore critical that the surgeon be familiar with hemostatic techniques in order to minimize intraoperative blood loss.…”

“…Thyroid tumors may occur in horses of all ages, but are most common in horses over 10 years of age, with pathological studies reporting an incidence of 30% for horses ≥10 years old and 75% in horses ≥20 years old . Thyroid enlargement is associated with a variety of clinical signs including: localized enlargement in the throat region, respiratory distress/dyspnea, abnormal respiratory noise, esophageal obstruction (choke), and reduced or limited movement of the head and neck, particularly when ridden …”

“…Hemithyroidectomy is an effective and safe procedure for cases where clinical signs such as dyspnea and dysphagia are associated with thyroid masses. The long‐term prognosis after surgery is excellent . The most commonly reported surgical complications include seroma formation (29%‐33%) and recurrent laryngeal nerve neuropathy (RLNN) 0%‐50% .…”

“…For this reason if a benign enlargement is detected as an incidental finding during clinical examination, a conservative approach can usually be recommended . Thyroidectomy (hemi‐ or bilateral) is performed with the affected horse under general anesthesia (GA) . However, risks and complications associated with GA can be a limiting factor for the overall outcome, with a mortality risk of 1% reported for healthy horses undergoing GA .…”