Use of Microscope-Integrated Near-Infrared Fluorescence for Enhancing Deep Lymphatic Vessel Detection during Supermicrosurgical Lymphaticovenous Anastomosis: A Longitudinal Cohort Study.

BACKGROUND

The default setting of microscope-integrated near-infrared fluorescence (MINIRF) using indocyanine green for locating superficial lymphatic vessels during lymphaticovenous anastomosis was limited to less than or equal to 70 percent intensity. The authors investigated whether maximizing the MINIRF intensity setting could increase the number of deep lymphatic vessels being found, thereby increasing the total number of lymphatic vessels for lymphaticovenous anastomosis.

METHODS

This longitudinal cohort study enrolled 94 patients (86 female and eight male patients) with lower limb lymphedema. Superficial lymphatic vessels were identified with the MINIRF default setting, before maximal intensity was used for deep lymphatic vessel detection. Primary/secondary endpoints included the number of superficial and deep lymphatic vessels identified. No control was used. Demographic data, intraoperative findings [including superficial and deep (indocyanine green-enhanced and non-indocyanine green-enhanced) lymphatic vessels], and severity of lymphosclerosis were recorded. Data in three regions of the lower limb (i.e., foot/above ankle, below knee, and thigh) were compared.

RESULTS

A total of 481 lymphatic vessels were identified, comprising 260 superficial and 221 deep lymphatic vessels. The median number of lymphatic vessels found per patient was five (interquartile range, four to six), and the median lymphatic vessel size was 0.63 mm (interquartile range, 0.5 to 0.8 mm). No difference was found in number (p = 0.360), size (p = 0.215), or severity of lymphosclerosis (p = 0.226) between the overall superficial and deep lymphatic vessels in the three lower limb regions.

CONCLUSIONS

Deep lymphatic vessel detection can be aided by maximizing MINIRF intensity. These deep lymphatic vessels are comparable to superficial lymphatic vessels in number, size, and functionality, making them potentially valuable for lymphedema improvement.

CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, II.