Surgical Intern Toronto Animal Health partners Corvallis, Oregon
Accurate Location of the Targeted Lymph Node in a Mandibular Lymphocentrum: A Canine Cadaveric Study. Bae S, Townsend K, Milovancev M. Oregon State University, Department of Clinical Sciences, Corvallis, OR.
Accurate tumor staging has a profound impact on the care and prognosis of oncologic patients. Due to the presence of multiple lymph nodes (LNs) in the mandibular lymphocentrum, clinicians may not know which specific LN they could be sampling during routine fine needle aspirations, which introduces a source of uncertainty in accurately determining patient clinical stage. The objective of this cadaveric study was to determine the success of targeting specific mandibular LNs by palpation alone, verified by computed tomography (CT). A 1.5-inch, 22-gauge needle was inserted into the targeted LN (selected by block randomization) and success was evaluated by CT images in transverse, sagittal, and dorsal views. The overall success rate of inserting the needle into the targeted LN was 55.9%. One variable was significantly associated with successful needle insertion: lateral (vs. medial) LN location (P = 0.019). In addition, the distance from the LN to the ventral skin surface in the successful group appeared to be shorter compared to the unsuccessful group (P = 0.066). These findings suggest that physical accessibility of the LN is the most important factor for successful needle insertion using palpation. Palpation-based sampling of specific mandibular LNs is often inaccurate and if targeted sampling of a particular LN is required, additional methods should be used to guide accurate sample acquisition.