Effective and efficient lymphaticovenular anastomosis using preoperative ultrasound detection technique of lymphatic vessels in lower extremity lymphedema.

Akitatsu Hayashi, Nobuko Hayashi, Hidehiko Yoshimatsu, Takumi Yamamoto. J Surg Oncol. 2017;1–9

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Effective and efficient lymphaticovenular anastomosis using preoperative ultrasound detection technique of lymphatic vessels in lower extremity lymphedema

Akitatsu Hayashi, Nobuko Hayashi, Hidehiko Yoshimatsu, Takumi Yamamoto. J Surg Oncol. 2017;1–9

Background:

Identification of functional lymphatic vessels and localization of lymphatic vessels are important for lymphaticovenular anastomosis (LVA). Indocyanine green (ICG) lymphography is useful for localization of superficial lymphatic vessels where dermal backflow is not observed, but not for lymphatic vessels in deep layer or where dermal backflow is observed. Ultrasound has been applied in LVA and is considered useful for localization of lymphatic vessels with ICG lymphography cannot be visualized.

Methods:

Fifty-five secondary lower extremity lymphedema (LEL) patients who underwent LVA were classified into two groups, ultrasound-detection-of-lymphatic group (US group, n=29) and non-ultrasound-detection-of-lymphatic group (non-US group ,n=26), and assessed. Sensitivity and specificity to detect lymphatic vessel were evaluated in US group. Intraoperative findings, required time for dissecting lymphatic vessels and veins, length of skin incision, and postoperative lymphedematous volume reduction were compared between the groups.

Results:

Lymphatic vessels were detected in all incisions in both groups. LVA resulted in 232 anastomoses in US group and 210 anastomoses in non-US group. Sensitivity and specificity of ultrasound for detection of lymphatic vessels were 88.2% and 92.7%, respectively. Diameter of lymphatic vessels found in US group was significantly larger than that in non-US group (0.66±0.18 vs0.45±0.20mm; P=0.042). Time required for dissecting lymphatic vessels and veins in US group was shorter than that in non-US group (9.2±1.7 vs 14.7±2.4min; P=0.026). LEL index reduction was significantly greater in US group than that in non-US group (26.7±13.6 vs 7.8±11.3; P=0.031).

Conclusions:

Ultrasound-guided detection of lymphatic vessels for lymphedema was performed with high precision, and allows easier and more effective LVA surgery.

Main findings

  • Small sample size.
  • Preoperative identification of functional lymphatic vessels and veins can contribute to shorter operative time in an attempt to establish as many bypasses as possible in performing LVA.
  • ICG lymphography cannot visualize lymphatic flow in the deep layer of subcutaneous tissue, or one that is masked beneath dermal backflow patterns, particularly in stardust and diffuse patterns.
  • ICG lymphography cannot be performed on patients who are allergic to iodine.
  • For detection of lymphatic vessels in a region masked by dermal backflow pattern, or in patients with allergic reactions to ICG, the authors believe ultrasound, which is more common and simple, could substitute for ICG lymphography. Lymphatic vessels were reported to be illustrated as intermittent homogeneous, hypoechoic and specular misshapen images with ultrasonography in the lower leg of healthy volunteers.
  • In the US group, based on the characteristic findings, lymphatic vessels were identified preoperatively using ultrasound in the groin, the thigh, the knee, and the lower leg, where ICG lymphography showed dermal back flow or in patients on whom ICG could not be used.
  • The number of true positive was 225, and that of false positive was 16. The number of true negative was 204 and that of false negative was 30. Sensitivity and specificity of ultrasound for detection of lymphatic vessels were 88.2% and 92.7%, respectively. Lymphatic vessels in the thigh and knee region existed in a deeper layer than the ones in the groin and the lower leg.
  • Post operative reduction in the lower extremity lymphedema index was significantly greater in the US group than in the non-US group.
  • This study also showed statistically larger size in the diameter of lymphatic vessels, significant reduction in required time for dissecting lymphatic vessels and veins, and significant decrease in lower extremity lymphedema index in the US group.
  • The authors suggests detection of lymphatic vessel in the thigh and the knee is difficult with ICG lymphography. Lymphatic vessels in the thigh and the knee often reside in a deep, fatty layer, making their detection even more challenging for surgeons; unsuccessful detection of lymphatic vessels is common in this area.