Unilateral thyroidectomy in 6 horses.

The research article investigates the outcomes and complications of unilateral thyroidectomy, a surgery to remove a part of the thyroid gland, performed on 6 horses exhibiting rapidly growing thyroid masses. The surgical technique was evaluated and possible complications such as laryngeal hemiplegia were identified.

Methodology

The study is based on a retrospective analysis which includes:

• An examination of the medical records of horses which underwent unilateral thyroidectomy between 1985 and 2000.
• A consideration of signalment, physical examinations, clinical and ultrasonographic findings, surgical techniques, complications, and outcomes.
• A minimum follow-up period of six months post-surgery.

Results

The examined records indicated that:

• All the horses were experiencing significant thyroid enlargement, evident on ultrasonography, ranging 125 to 990 cm³ in size.
• Three horses faced tracheal compression and two of these showed an intolerance to exercise.
• The texture of the thyroid masses differed – some were heterogeneous, some cystic, and others homogeneous.
• Post-surgery, three horses developed ipsilateral laryngeal hemiplegia.
• Surgically removed thyroid masses were diagnosed as adrenal adenoma, C-cell compact carcinoma, and adenocarcinoma.
• No signs of tumor recurrence or metastatic disease were reported within a follow-up period of 6 to 14 months post-surgery.

Conclusions

Based on the results, the study made certain conclusions:

• Unilateral thyroidectomy can be successfully conducted in horses and can be an effective treatment for large thyroid tumors.
• Despite its efficacy, laryngeal hemiplegia was identified as an important surgical complication.
• The ultrasonographic examination proved useful in identifying thyroid enlargement and location, but it could not adequately distinguish the tumor type.
• Thyroidectomy is fairly rare surgical procedure in horses and poses a risk of causing damage to the recurrent laryngeal nerve.
• Laryngoscopic examination pre and post-surgery and careful isolation of the recurrent laryngeal nerve during surgery was recommended to prevent possible complications.