Clinical characteristics of pneumorrhachis in dogs and cats: a retrospective study of 125 cases.

BACKGROUND

Pneumorrhachis (PR), defined as gas within the vertebral canal, is an uncommon finding, and its clinical relevance and relationship to the vacuum phenomenon (VP) have not been systematically evaluated.

HYPOTHESIS/

OBJECTIVES

To characterize the anatomical distribution of PR in dogs and cats undergoing computed tomography (CT) and to assess its relationship with signalment, VP, and concurrent neurological and non-neurological conditions.

ANIMALS: One hundred nineteen dogs and 6 cats with PR identified on CT between 2015 and 2023.

METHODS

Retrospective, descriptive study of medical records and CT reports. Cases were included when PR was documented in the radiology report, clinical and imaging information was available. Data included signalment, PR distribution, VP presence, final diagnosis categorized as neurological, non-neurological, postoperative, or no identified cause.

RESULTS

Pneumorrhachis was identified with neurological conditions in 60/119 dogs (50%), including intervertebral disc disease (IVDD) in 50/60 (83%). Among IVDD-related PR, Hansen type I occurred in 32/50 (64%) cases. A VP was present in 23/50 dogs (46%), co-localized with the affected intervertebral disc in 78%. Non-neurological conditions accounted for 45/119 (38%) dogs, mainly neoplastic (44%) and respiratory (36%), with VP infrequently detected. Pneumorrhachis occurred postoperatively in 12/119 dogs. Two dogs (2%) had PR and epaxial muscle pain without an identifiable cause. In cats, PR was associated with neurological (2/6), non-neurological conditions (2/6), and postoperatively (2/6). No cases involved IVDD or VP.

CONCLUSIONS AND CLINICAL

IMPORTANCE

Pneumorrhachis in dogs and cats is considered an uncommon CT finding occurring with neurological and non-neurological conditions. Although often accompanying IVDD in dogs, PR was frequently incidental.