Pneumomediastinum and pneumorrhachis following sinoscopy in an adult horse

Abstract

A horse presented to the referral hospital for pyrexia and unilateral nasal discharge. Computed tomographic examination demonstrated changes consistent with unilateral primary sinusitis. Frontal and rostral maxillary trephination facilitated sinoscopy and lavage of the paranasal sinuses. Postoperatively, subcutaneous emphysema of the head and neck developed and upon further investigation pneumomediastinum and pneumorrhachis were diagnosed on radiographic examination. The trephine portals were the likely entry point of the subcutaneous emphysema; gas then dissected through the fascial planes of the neck into the mediastinum. It is hypothesised that gas also extended along cervical fascial planes and through intervertebral foramina to enter the spinal canal causing pneumorrhachis. This is accordant with cases in human medicine and current understanding of mediastinal anatomy. The horse recovered with conservative management; however, it is noteworthy that pneumomediastinum and pneumorrhachis are potential complications of sinoscopy. Pneumothorax can subsequently develop, which could be life threatening.