Complications of medial retropharyngeal, axillary, and ilio-sacral lymphadenectomy in 127 dogs with malignant tumors

Objective To describe the complications of medial retropharyngeal, axillary, and ilio-sacral lymphadenectomy in dogs with malignant tumors, and to identify possible risk factors.Study design Retrospective cohort study.Animals A total of 140 surgical accesses (86 axillary, 27 ilio-sacral, 27 retropharyngeal) in 127 dogs.Methods Dogs with cutaneous/subcutaneous cancer undergoing staging, lymph node (LN) mapping and extirpation of medial retropharyngeal, axillary, and/or ilio-sacral LNs, with a minimum follow-up of 1 month, were included. Retrieved information included signalment, tumor histotype, LN characteristics, excision of contiguous LNs, anesthesia duration, intra- and postoperative complications. Data were statistically analyzed to identify risk factors for complication development.Results Intraoperative complications were registered in 3/140 (2%) procedures, including hemorrhage during medial iliac lymphadenectomy (2/27, 7%) and difficulty locating the axillary LN (1/86, 1%). Postoperative complications occurred in 32/140 (23%) cases, with rates of 41% (11/27) following ilio-sacral lymphadenectomy, 26% (7/27) after medial retropharyngeal lymphadenectomy, and 16% (14/86) following axillary lymphadenectomy. Ilio-sacral lymphadenectomy presented a higher risk of intraoperative (p = .033) and postoperative complications (p = .020). Enlarged (p = .030) or metastatic (p = .030) LNs were more prone to develop intraoperative complications. No risk factor retained significance on multivariate analysis. Median follow-up, conducted through physical examination, was 225 days (range, 30-1735).Conclusion Medial retropharyngeal and axillary lymphadenectomies were generally safe, associated with minor and easily manageable complications. Conversely, ilio-sacral lymphadenectomy carried a higher risk of intraoperative complications, particularly in cases with enlarged LNs, and postoperative complications, potentially related to the caudal laparotomic approach.Clinical significance Lymphadenectomies of medial retropharyngeal, axillary, and ilio-sacral lymph nodes present relatively low complication rates.