Lymph vessel mapping in femoropopliteal bypass surgery, a feasability study

Lymph edema is a common complication after vascular surgery. An incidence of
50-100% is described after surgical infrainguinal arterial reconstruction,
usually during the mobilization period. The vulnerable lymph vessels are
situated next to the arteries and veins, whereby there is a substantial
possibility of injuring these lymph vessels during an operation. Peroperative
injury of lymph vessels during vascular surgery is an important cause of wound
leakage, seroma and lymph edema.

The pathofysiologic mechanism in lymph edema is not totally cleared yet, but
injury to the lymph vessels seems to play an important role. Lymph edema arises
when the balance is disturbed between rate of production and capacity of the
lymphatic system to remove the increased volume of lymph. An abnormal
accumulation of proteins and fluid exists. Increased production of interstitial
fluid after successful revascularization leads to an increased lymphatic load.
Also, the transport capacity in the surgical area is disturbed, because of
obstruction and injury to the lymphatic system.
A number of studies have been performed in patients with lymph edema after
bypass surgery, at which the lymph vessels were visualized postoperatively with
lymphangiography. This showed injury and abnormal anatomy of the lymph vessels
in patients with edema. Ideally intact lymph vessels would cause less
postoperative edema. Injury to the lymphatic system should be limited during
surgery, but the big concern is that they are very thin and difficult to
visualize.

In practice one attempts to prevent or decrease edema by elevating the leg,
using support hosiery and slow mobilization. Until now this has not led to
satisfactory results. The symptoms patients experience are progressive
swelling, a heavy or tight sensation, fatigue or pain in their limbs and
limitations of movement. Postoperative edema has a negative effect on
mobilization of already vulnerable, older patients and their daily lives.
Limited and altered movements may lead to possible invalidity of the patient.
Also, wearing support hosiery is inconvenient and help is often needed.
Long-term issues can be an increased risk of developing skin lesions and
infections, like cellulitis and erysipelas. Lymph edema is often an unexpected
and disabling condition that has a negative influence on the quality of life.
Thus preventing or reducing postoperative lymph edema is necessary.

Up until now methylene blue has been used for researching lymph node
metastasis, it visualizes the lymph vessels and nodes. This method could also
be used to visualize the lymph vessels in the legs, so these can be saved
during surgery, what possibly may lead to decreased postoperative edema.

To prove that lymph vessels in the legs can be visualized with methylene blue,
so they can be spared during surgery, what possibly may lead to decreased
postoperative lymph edema.

Hypothesis: Methylene blue visualizes lymph vessels in the legs, so they can be
spared preoperatively.

The study *Lymph vessel mapping in femoropoliteal bypass surgery* is a
feasibility study. When this study proves that is possible to visualize lymph
vessels, it will be followed by a randomized study in which bypass surgery with
lymph vessel mapping will be compared with bypass surgery without lymph vessel
mapping, with as outcome postoperative edema and other related complications.
This study will be carried out in the Alysis Zorggroep, location Rijnstate in
Arnhem.
Ten patients with an indication for femoropopliteal bypass surgery, without
previous surgical intervention of the legs, will be included. They all ought to
sign the informed consent form.
Preoperatively the results will be scored in a standardized manner, so no
further follow-up is indicated for this study.

Injection with methylene blue:
1% novocaïne will be added to the injection with methylene blue in a 1:3 ratio.
Between dig 1 and dig 2 0,5ml will be injected, 0,25ml between dig 2 and dig 3
and 0,25ml between dig 4 and dig 5. The injections will be given 45 minutes
before surgery.

The injections can be uncomfortable, therefore 1% novocaïne will be added to
the methylene blue in a 1:3 ratio. The risks for the patients don*t differ from
the usual risks in femoropopliteal bypass surgery: wound infection, bleeding,
thrombosis, lung embolus, pneumonia, cystitis or myocardial infarction. The
addition of methylene blue does not increase the risks on these complications.
It is also possible that patients show an allergic reaction on methylene blue.