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Utility of Indocyanine Green Fluorescence Lymphography in Identifying the Source of Persistent Groin Lymphorrhea

Summary: Surgical manipulation of the groin can result in lymphatic injury in a significant number of patients leading to poor wound healing or infectious complications. Surgical repair of lymphatic injury is greatly aided by the precise and prompt intraoperative localization of the injured lymphatic vessels. We assessed and identified lymphatic leaks in 2 cases of surgical wound lymphorrhea occurring after instrumentation of the groin using laser-assisted indocyanine green lymphography paired with isosulfan blue injection. Both cases healed without complication, and no lymphatic leak recurrence was observed during postoperative follow-up. Laser-assisted indocyanine green lymphography is a useful adjunct in the management of lymphatic leaks after surgery of the groin and may have potential for prophylactic evaluation of high-risk groin wounds.


PATIENTS AND METHODS
Using ICG lymphography, we identified and ligated symptomatic lymphatic leaks in 2 patients (1 man, 1 woman; 50-58 years old) occurring after surgical instrumentation of the groin for central vascular access (Table 1).

Operative Technique
Open wound exploration was carried out in a standard fashion before performance of ICG lymphography. A 1.0 mL intradermal injection of a 50:50 mixture of ICG (2.5 mg/mL; ICG for Injection USP, PULSION Medical Systems, LifeCell Corporation) and saline in the first web space of the ipsilateral lower extremity was placed intraoperatively. The centripetal progression of the dye and visual identification of the damaged lymphatic vessel were made using the SPY Elite system (LifeCell Corporation/Novadaq Technologies, Canada). The ICG dye mixture reached the level of the wound in approximately 4 minutes. Identification was verified with a similar injection of 0.5 mL of 1% isosulfan blue (Lymphazurin). The damaged lymphatic channel was suture ligated, and the wound was closed in layers over a drain.

Case Report 1
A 51-year-old man referred for surgical management of refractory high-volume groin wound lymphatic leak underwent intraoperative ICG lymphography as described. The lymphatic leak was easily identified and clamped before confirmation with isosulfan blue injection (Fig. 1). The damaged lymphatic channel was suture ligated, and the wound was closed in layers over a closed suction drain. Follow-up at 30 and 90 days revealed no evidence of leak recurrence, fluid collection, or extremity edema.

Case Report 2
A 58-year-old woman developed limb-threatening ischemia immediately after coronary bypass and aortic valve replacement. Thrombectomy and patch grafting performed on the left common femoral artery was closed with a sartorius transposition flap for soft tissue coverage. Persistently high (~800 mL/d) drain output was suggestive of lymphatic leak. After conservative measures failed, the patient returned to the operating room for exploration and ligation using ICG lymphography. The lymphatic leak was identified, clipped, and the wound closed in layers over a closed suction drain. Follow-up at 32 days showed no evidence of continued lymphatic leak.

DISCUSSION
Postoperative lymphorrhea or lymphocele, seen after 1.8%-18.9% of all cases of groin surgery, increases the risk of infection, chronic wounds, and the need for additional procedures. 1 When surgical intervention is necessary, intraoperative lymphatic imaging aids the identification of involved lymphatic channels, reducing the risk of inappropriately extensive dissection and inadequate ligation. ICG dye is an emerging lymphatic imaging adjunct with demonstrated utility in sentinel node surgery and lymphatic mapping in lymphedema and intrathoracic chyle leak. Although the use of ICG lymphography was reported in one case of pudendal lymphocutaneous fistula, this series is the first to demonstrate the utility of intraoperative ICG lymphography for identification and treatment of lymphatic leaks in the groin. 7,8 The utility of intradermal ICG dye injection has expanded to lymphography with the use of laser-assisted near-infrared (NIR) imaging systems, allowing evaluation of lymphedema, lymphatic backflow, and lymphatic mapping. 9-12 ICG dye is well tolerated with a side effect profile comparable with that of isosulfan blue dye as proven by more than 40 years of use for ophthalmologic angiography Similar to isosulfan blue, ICG stains the area of lymphatic leak rendering subsequent injections less useful. ICG has the advantage over isosulfan blue of being detectable only when energized with NIR energy, leaving the operative field visually unaltered under normal lighting. Additionally, laser-assisted ICG lymphography imaging enables up to 2 cm of tissue penetration allowing real-time visualization of lymphatic flow and anticipatory localization guidance. In our series, intraoperative ICG injection identified the leak within 4 minutes..
ICG lymphography is a valuable method for intraoperative identification of lymphatic leaks and functional evaluation of the lymphatic system. 9,10,14-16 Improved lymphatic target identification using 2 modes of lymphatic mapping is well documented in oncologic surgery with both lymphoscintigraphy and ICG imaging.. 17 Furthermore, ICG is more effective than isosulfan blue in sentinel node lymphography, identifying 100% of sentinel lymph nodes identified by lymphoscintigraphy, whereas isosulfan blue identified only 86%. 18,19 When using the dual-dye technique for leak identification, ICG lymphography should be performed first so that the operative field remains visually unobscured. ICG lymphography is limited by the need for digital imaging equipment, whereas isosulfan blue requires no additional equipment. Institutions can increase utilization of existing NIR imaging equipment through performance of lymphography procedures.
Additionally, ICG angiography with the intravenous administration of ICG can be used during the same procedure to evaluate tissue perfusion. Due to the tissue staining that occurs with lymphography, we recommend performance of ICG angiography before lymphography procedures.

CONCLUSIONS
ICG lymphography was successfully used to identify lymphatic leaks responsible for persistent lymphorrhea after groin surgery. The procedure provided a satisfactory outcome in 2 complicated patients with multiple comorbidities. The use of laser-assisted ICG lymphography for initial lymphatic injury identification allowed for subsequent dissection in a field that was not obscured by a visible dye. These cases demonstrate that ICG lymphography is a useful tool for the treatment of a symptomatic lymphatic leak and should be considered in the diagnostic and treatment algorithm.

Luther (Tripp) Holton III, MD
Division of Plastic Surgery University of Maryland School of Medicine 22 South Greene Street S8D18, Baltimore, MD 21201 E-mail: lholton@smail.umaryland.edu