Partial Horner's Syndrome Following Thyroidectomy Without Lateral Neck Dissection: A Rare Case Report and Literature Review.

Horner's syndrome is a rare complication of thyroid surgery and is most commonly reported as a complication associated with lateral neck dissection. We present the case of a 46-year-old woman who developed a partial Horner's syndrome following hemithyroidectomy and central neck dissection, without lateral neck dissection. The patient underwent right hemithyroidectomy and central neck dissection for a TIRADS-5 nodule and developed right sided facial anhidrosis and absence of right-sided facial erythema on exertion 6 weeks post-operatively. No ocular involvement was detected. Neurologist review confirmed partial Horner's syndrome, which eventually resolved. The literature regarding development of Horner's syndrome as a complication of thyroid surgery without lateral neck dissection was reviewed via PubMed. All English language publications of adult patients developing features of Horner's syndrome after open thyroid surgery (hemithyroidectomy or thyroidectomy, +/- central neck dissection) were included. Twenty one cases of Horner's syndrome following thyroid surgery without lateral neck dissection were identified. Interestingly, only four of these cases featured anhidrosis, and no case reported asymmetrical facial erythema. Four possible mechanisms of cervical sympathetic chain dysfunction resulting in Horner's syndrome post-thyroidectomy have been proposed: neuropraxia from retraction; mass effect from post-operative haematoma; ischaemia-induced nerve damage; damage to communicating fibres during repeated inspection of the recurrent laryngeal nerve. To our knowledge, this is the only reported case of a post-thyroidectomy partial Horner's syndrome with associated asymmetrical flushing.