Novel Thoracoscopic Approach Resolves Rare Mediastinal Abscesses in Dogs—Rapid Recovery Achieved

Minimally invasive treatment and short-term outcomes of a caudal mediastinal paraesophageal abscess (CMPA) in two dogs

Kathryn Biehl, Rachel W. Williams, Logan Scheuermann, Federico R. Vilaplana Grosso, J. Brad Case

Background

Caudal mediastinal paraesophageal abscesses (CMPA) are rare in dogs, and their underlying cause is poorly understood. Human cases often arise from penetrating esophageal foreign bodies or perforation, but veterinary literature documents few cases, mostly treated with open thoracotomy. Previous reports suggest good prognosis with surgery, but short- and long-term outcomes remain sparsely documented. No veterinary reports had described video-assisted thoracic surgery (VATS) for CMPA before this study. This report aimed to describe presentation, diagnostic findings, minimally invasive surgical management, and outcomes for two canine cases treated using VATS.

Methods

This retrospective case series evaluated two client-owned dogs diagnosed with CMPA via CT. Both dogs underwent thoracoscopic exploration, abscess incision, debridement, and lavage using sharp dissection and a vessel-sealing device. One case required partial conversion to a thoracoscopic-assisted approach because aerated lung tissue impaired visualization, and one employed one-lung ventilation to facilitate full thoracoscopic access. Abscess tissue and fluid were submitted for culture and histopathology. Postoperative management included thoracostomy drainage, antibiotic therapy, analgesia, and scheduled follow-up evaluations.

Results

Both dogs had large, thick-walled paraesophageal abscesses protruding through the esophageal hiatus and causing mass effect on adjacent structures. No foreign material was identified on CT, esophagoscopy (when performed), or intraoperative inspection. Cultures were negative in both cases, and histopathology demonstrated chronic suppurative or neutrophilic inflammation without identifiable pathogens. Surgical debridement and lavage were completed successfully, with only minor complications noted (hemorrhage requiring vessel sealing, mild hypoxia during recovery, transient hypoglycemia). Both dogs recovered uneventfully, were discharged within 3–4 days, and showed no recurrence at 7-month telephone follow-up. Repeat imaging in one dog showed only mild residual soft-tissue opacity without evidence of abscess recurrence.

Limitations

This report includes only two cases, limiting generalizability. Neither dog’s underlying etiology was determined, consistent with other CMPA reports. Esophagoscopy was not performed in one case, raising the possibility that a mucosal lesion could have been missed. The absence of identifiable organisms may reflect sampling limitations or prior antimicrobial therapy. Lack of standardized postoperative imaging in Case 1 restricts assessment of radiographic resolution. As a retrospective case series without controls, comparisons to open surgical approaches must be interpreted cautiously.

Conclusions

VATS was a feasible and effective minimally invasive approach for treating CMPA in dogs, allowing adequate exploration, debridement, and drainage with minimal morbidity. Both cases recovered quickly with short hospitalization times and achieved excellent short-term and 7-month outcomes. VATS may offer visualization advantages over open surgery and could enable earlier recovery, though prospective studies comparing minimally invasive and open approaches are needed. Determining the etiology of CMPA remains challenging, as neither foreign bodies nor infectious agents were identified.

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