Accurate lymph node (LN) retrieval during colorectal carcinoma resection is pivotal
for precise N-staging and the determination of adjuvant therapy. Current guidelines
recommend the examination of at least 12 mesocolic or mesorectal lymph nodes for accurate
staging. Traditional histological processing techniques, reliant on visual inspection
and palpation, are time-consuming and heavily dependent on the examiner’s expertise
and availability. Various methods have been documented to enhance LN retrieval from
colorectal specimens, including intra-arterial ex vivo methylene blue injection. Recent
studies have explored the utility of indocyanine green (ICG) fluorescence imaging
for visualizing pericolic lymph nodes and identifying sentinel lymph nodes in colorectal
malignancies. This study included 10 patients who underwent colon resection for malignant
tumors. During surgery, intravenous ICG dye and an endoscopic camera were employed
to assess intestinal perfusion. Post-resection, ex vivo intra-arterial administration
of ICG dye was performed on the specimens, followed by routine histological processing
and an ICG-assisted lymph node dissection. The objective was to evaluate whether ICG
imaging could identify additional lymph nodes compared to routine manual dissection
and to assess the clinical relevance of these findings. For each patient, a minimum
of 12 lymph nodes (median = 25.5, interquartile range = 12.25, maximum = 33) were
examined. ICG imaging facilitated the detection of a median of three additional lymph
nodes not identified during routine processing. Metastatic lymph nodes were found
in four patients however no additional metastatic nodes were detected with ICG assistance.
Our findings suggest that ex vivo intra-arterial administration of indocyanine green
dye can augment lymph node dissection, particularly in cases where the number of lymph
nodes retrieved is below the recommended threshold of 12.
