Management of Groin Lymphocele and Lymph Fistula

Incidence

The lower extremity lymphatic system consists of vertically ascending lymph vessels that enter the superficial and deep inguinal lymph nodes. Surgical dissection of the femoral triangle leads to disruption of the lymphatic channels and the potential for a lymphocele and fistula. Open lymph vessels seal within 48 hours and begin to regenerate within 8 days. Small lymphatic leaks do not pose a problem and resolve without intervention. Poor operative technique, inguinal adenopathy, scar tissue caused by redo groin dissections, and extensive femoral triangle dissections have been implicated as risk factors for the development of a lymphocele or fistula. In particular, redo groin procedures have an increased risk of developing lymphatic complications as a result of scarring and wound rigidity.

Some have argued that the type of incision—oblique versus transverse versus lateral—affected the incidence of lymphatic wound complications. Haaverstad demonstrated no difference in the incidence of developing a lymphocutaneous fistula or lymphocele between patients who underwent a lateral approach to the femoral vessels versus a direct medial approach. Others have documented that a vertical skin incision leads to more fistulas than a transverse incision and that lymphocutaneous fistulas were more likely with transverse skin incisions. A more recent study by Pleog demonstrated no difference in the incidence of fistulas in patients who underwent a lateral versus a direct approach to the common femoral artery. Regardless of the type of incision, all surgeons agree that meticulous dissection, staying directly over the vessels of interest, with careful attention to ligation or cautery of the lymphatic vessels and appropriate layered closure of the incision reduces the potential for lymphatic complications.

The incidence of lymphatic complications with dissection of the femoral triangle ranges from 0.5% to 1.8% for first-time operations but increases to 8.1% for redo procedures. When a lymphocele or fistula is present, the incidence of infectious complications is as high as 23%.

Femoral triangle lymphatic complications most commonly occur following axillofemoral, aortofemoral, femorofemoral, femoropopliteal, or femorotibial artery bypass procedures. Aortobifemoral bypass procedures have the highest incidence. Murphy found lymphocutaneous fistulas were more likely to develop in older patients and in those who underwent aortobifemoral bypass for limb salvage rather than for claudication.

Clinical Presentation and Diagnosis

Prompt recognition of a fistula or a lymphocele is essential to successful therapy. Lymphocele should be suspected if there is a painless, pulseless soft mass in the groin. A painful and erythematous mass should be considered an infected lymphocele until proved otherwise. The differential diagnosis of swelling in the femoral triangle after surgery includes femoral pseudoaneurysm, seroma, hematoma, and abscess.

The use of vascular imaging such as duplex ultrasonography can aid in the diagnosis of lymphoceles. Duplex ultrasonography can establish if the mass is avascular, which rules out a pseudoaneurysm. A lymphocele is typified by a hypoechoic or anechoic image, occasionally with internal septa and scattered echoes denoting debris. Computed tomography of a lymphocele usually demonstrates low Hounsfield numbers (occasionally negative values). A lymphocele should only be aspirated for diagnosis if there is diagnostic uncertainty or if it is large and symptomatic, because there is procedural risk of bacterial contamination. The fluid must be aspirated under sterile technique with an 18- to 21-gauge needle. Lymphocele fluid is clear, has low protein content (0.5 to 2 g/dL), and can contain lymphocytes.

LCFs are diagnosed by the persistent drainage of fluid from the incision, often at a site in the lower half of the wound. Fistulas may be diagnosed within 3 to 4 days after a procedure, but in many cases they do not become apparent for up to 10 days. Lymphorrhea can occasionally exceed 500 mL in 24 hours. The presence of a fistula suggests some degree of wound dehiscence, and thus the tract can serve as a portal for bacteria and graft contamination.