The Michigan Vascular Access/MiDRE primer in Vascular Access
Chapter 15 – Superficialization of brachiocephalic fistulas
Superficialization of brachiocephalic fistulas too deep to use: A strategy to utilize our hidden vascular assets!"
The ideal fistula is straight, large, and in a location easy to cannulate for dialysis. Fistulas using the cephalic vein running from wrist to shoulder most often approach this ideal, but in many patients those veins are deep, tortuous, or impossible to cannulate. Too frequently, patients are told that the have "bad veins" or that they cannot have a fistula. In the past, I myself have told patients with large arms and deep veins that they could not have a fistula. Fortunately I learned different, and now know better.
The cephalic vein in the forearm and the upper arm is associated with (bound down by) a layer of connective tissue from a point several inches above the wrist. Subcutaneous tissue (fat, "padding", "insulation") resides between that fascia and the skin. The more padding, the deeper the vein. We can ask the patient to lose weight to shrink this layer and bring the vein close to the skin, but this advice is often unreasonable.
|The fistula on the left is too deep. The fistula on the right has been superficialized|
Without this understanding the surgeon may feel a terrific thrill and state that the fistula is usable. Unfortunately, a vein is progressively more difficult to cannulate, and the inevitable infiltration creates local inflammation, soft tissue swelling, hematomas around the fistula and things get worse and worse. In general, if the fistula is deeper than wide on ultrasound, there will be problems cannulating. Dialysis will be painful, or unsuccessful. Resting the fistula to allow swelling to subside may allow the fistula to be used successfully, but just a s often this kind of wishful thinking avoids the evidence and subjects the patients to an monthly cycle of infiltration, resting the fistula, one or two (or none) successful cannulations, then re-infiltration, and on and on. The patient becomes wedded to the catheter, and dreads the fistula.
A deep brachiocephalic fistula with infiltration
The alternative is to move the vein closer to the skin and make it accessible for cannulation. Acceptance of this concept has allowed many people to have a fistula who were previously not thought to have that potential. Ordinarily, the vein is fistulized, and then superficialized later only if adequate growth is observed. Patients are happy to hear that a "bad" fistula can be moved and made usable. When the anatomy is clearly appreciated ahead of time, the two stage creation/superficialization plan can be laid out in advance, from the very first office visit. It need not come as a surprise, or as a failure, but the up-front agreed upon price for all the good living that produced that subcutaneous padding in the first place.
The cephalic vein in the upper arm is the one most often superficialized. Whether the draining vein of a forearm graft or fistula, or a fistula created at the elbow, in the old technique (now abandoned) a long incision is made medial to the vein and the vein freed from elbow to shoulder. Branches are divided, stenoses fixed, and the arterialized vein divided just above the elbow. The mobilized vein is drawn through a tunnel created lateral to the incision so that the fistula will not be cannulated through a scar, and the two ends reattached. When the incision is healed, the fistula can be used – usually in a matter of just a few weeks.
It is advantageous for the surgeon to make the judgment that a fistula should be superficialized before the fistula has been miscannulated and infiltrated. A deep fistula once seriously infiltrated may be inflamed, scarred, and difficult to dissect. Small branches ordinarily easily recognized may be transected instead, with inevitable bleeding, struggle and delay.
This superficialization is being done prior to any misguided attempts to cannulate it. Notice how clean and uninflammed the tissues are.
This patient is the same infiltrated patient depicted above. Note, in contrast to the previous picture of an uninfiltrated patient, that the vein is barely visible, and dissection bound to be tedious and possibly complicated.
Another abandoned technique is the "elevation" method, in which the vein is exposed through a long incision and parked under a subcutaneous flap, usually by closing the tissue underneath. This has an advantage of not requiring division of the fistula nor re-anastomosis, but is tedious, and requires a longer healing time.
Elevation of the fistula, parking it under a skin flap.
In the new "skip" technique (since 2006), three smaller incisions are made over the vein: one above the elbow, one in the mid-arm, and one just below the shoulder. The vein is isolated in each spot, then followed under the skin bridges between the incisions by lifting the edges with a retractor. Once all branches are divided, the vein is mobilized, divided, retunneled, and the two ends reconnected.
The advantage of the "skip techniques" is a shorter overall incision, a better cosmetic result, less patient reluctance, and less surgical reluctance to recommend a "shark-bite" incision. The disadvantage is a more tortuous operation for the surgeon.
The skip technique. The fistula will be divided nearest the antecubital origin, then tunneled and reanastomosed end to end. Occasionally, a new brachial anastomosis is performed.
If the vein is the draining vein of a forearm graft or fistula, it may not be necessary to place a catheter while the upper part heals, because the forearm portion continues to be usable. Eventually the forearm portion starts to fail, and the upper arm vein is connected to the brachial artery with abandonment of the forearm graft or fistula.
The alert reader will see that this is not a superficialized brachiocephalic fistula above a forearm access, but rather a transposed basilic vein above a forearm access. The principle is the same. The vein in the upper arm is moved to make it usable, while the forearm portion is actively being used without interruption from the surgery. Later, the upper portion can be re-anastomosed to the brachial artery at the elbow and the forearm portion abandoned.
Superficializing the cephalic vein in the forearm is also possible, but is less common. If depth is the only reason that a forearm fistula is unusable, then bringing it to the surface not only can make it functional, but also preserve and develop the upper arm veins for future use.
Veins deep in the upper extremity can be usable no matter how big the arm, and should be considered a "hidden asset" for the dialysis patient. Superficialization of fistulas running too deep is a "high-yield operation" in the hands of an experienced access surgeon. Every forearm graft should be considered a bridge to an upper arm fistula as a patient's lifetime need for dialysis access is considered in a proactive fashion.