Arterial Restoration -Something New, Something Old

Something that I recently promised Dr. James S.T. Yao, I will be working to publish on my stent removal and extended remote endarterectomy cases and techniques. Meanwhile, here is a talk.

When Better is Better Than Good

original bypass

The dictum that better is the enemy of good is one of the old chestnuts carried around surgery training forever. It is an admonition against an unhealthy perfectionism that arises from either vanity or self doubt, and in the worse cases, both. The typical scenario is a surgeon trying to make a textbook picture perfect result and finding the patient’s tissues lacking, will take down their work to make it better, and repeat this process while the patient and everyone else in the room lingers.

Trying to avoid this, many surgeons will try to avoid any difficulties -the bad patch of scar tissue, irradiated body parts, areas of prior infection. But the mental contortions involved in avoiding “perfect” can result in actual physical contortions that in the end don’t pay off in good enough. I have not been immune to this, and I don’t think any physician or surgeon can honestly say they haven’t experienced some variation on this.

This patient is a younger middle aged man who in his youth experienced a posterior dislocation of his left knee, resulting in an arterial transection. This was repaired with an in-situ graft. Subsequently, he had complications of osteomyelitis and had his knee fused after resection of his joint. He did well with this bypass for several decades, but it finally failed several years ago, and a new one was created (image above).

Rather than directing the graft in line as in the previous one, this was was taken from a medial exposure of the femoral artery and tunneled superficially around the fused knee to coil lateral, ending in the anterior tibial artery.

This graft in turn thrombosed and was lysed by the outside surgeons and underwent serial interventions of proximal and distal stenoses at the anastomoses. The patient, when I met him, was contemplating an above knee amputation as a path to returning to work as a nurse in a rural hospital.

While there should be no reason long bypasses should do any less better than short bypasses, I do have to say these things about this patient’s bypass:

  1. No vein is perfect and the longer your bypass, the more chances you will have that a segment of bad vein will end up in your bypass
  2. Turning flow sharply can cause harsh turbulence. Turbulence can cause transition of potential energy into kinetic energy which acts to damage intimal, resulting in intimal hyperplasia.
  3. Thrombosis is a sure sign that your graft is disadvantaged, and the longer the period of thrombosis, the longer the intima “cooks” in the inflammatory response that accompanies thrombosis, making the vein graft even more vulnerable to subsequent intimal hyperplasia, thrombosis, or stricture.
  4. A high flow, small diameter vein graft entering a larger, disease free bed results in more turbulence but also Bernoulli effects that cause the graft to close intermittently, vibrating like one of those party favors that make a Bronx Cheer (a Heimlich valve). This is the cause I think of the distal long segment narrowing on this graft.

This patient was decided on amputation when our service was consulted, and after reviewing his CTA, I offered balloon angioplasty as his symptoms were primarily of paresthesia and neuropathic pain. I used cutting balloons and got angiographically satisfactory results.

intervention

The patient, although he admitted to feeling much better, was sad. He relayed that he had felt this way several times before, only to have his life interrupted by pain and weakness signaling a restenosis.

 

A direct graft would require about 10 centimeters of vein
 
It was only a month later when I heard the patient had returned with the same symptoms. He wasn’t angry nor full of any “I told you so” that frankly I was muttering to myself. Reviewing his CTA, he had restenosed to a pinhole. The vein, to use a scientific term, was “no good.”

The other interesting finding was that he had an abundance of very good vein. Following surgical dictum, his original and subsequent surgeons had used his vein from his contralateral saphenous vein. His right leg, fused at the knee, lacked a good calf muscle pump action. While there were no varicose veins, the greater and lesser saphenous veins were large and generous conduits, at least by 3DVR imagery, confirmed on duplex (image below, white arrows).

veins
3DVR showing presence of potential conduit

The extant arteries were smooth and plaque-free. I decided to harvest his lesser saphenous vein and through the same incision expose his distal superficial femoral artery and tibioperoneal trunk. While I anticipated some scarring, I was confident that the sections of artery I wanted to expose were easy to access because of some distance from the fused knee.

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On left short saphenous vein was harvested then same exposure used to expose TP Trunk

The picture shows the exposure and reversed vein graft in-situ, using the segment of lesser saphenous vein. As in prior experience in redo surgery, you can never know if a dissection will be easy or hard simply based on fear or concern for breaking something. It’s not until you start bushwacking –carving through scar and dealing with extraneous bleeding will you learn whether it was easy or hard. You can only be certain it was necessary. The only hitch was the femoral artery while well exposed, was buried in scar, and I chose not to get circumferential control as I was fairly deep, and had avid backbleeding from a posteriorly oriented collateral that required a mass clamp of the deep tissues.

Will this work better? Don’t know but it has a good chance, and I think a better chance. It is a large vein oriented in a straight path over a short distance going from good artery to good artery. This is better theoretically than a long meandering bypass with smaller vein. 

An Easy Way to Perform BKA -Treat it Like Plastic Surgeon

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At one time, I was performing below knee amputations in the same way that most textbooks prescribe. This patient presented with severe foot and leg infection with exposed tendons and cellulitis secondary to advanced diabetic neuropathy and arteriopathy. Sketch12683544

My sketch above showed the situation which we treated with two stage guillotine and final BKA. At the final stage, standard technique involves creating the classic flap shown below.

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This is a tricky flap to make well because there are many variables -the amount of muscle left, the thickness of the subcutaneous fat, the vascular supply, etc. The biggest criticism I have of this flap is that it is prone to edema particularly in the meaty posterior flap, putting great stress on the skin sutures or staples. This then creates fat or skin necrosis in the posterior flap, or muscle necrosis resulting in wound infections and hospital readmissions, which are particularly at risk for need for further leg amputation in these patients with diabetes. I have to confess, while I could figure out how to cut the flap in the end, it was really hard to teach, and if it is hard to teach, you have to figure out a better way.

Here is the better way. The idea goes to the concept that the weight is borne in a distributive ring around the stump. The muscle on the tibia does not create a heel to bear weight on and so serves only the purpose of delivering blood to the overlying skin. So you only need the gastrocnemii and Achilles tendon for fascial closure, and maybe a little soleus. The elimination of posterior compartment muscle bulk greatly reduces the tension on the fascia and skin.

The incision can be simplified by cutting the flap along an oblique 2D plane -a light saber cut!

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The posterior flap is reduced to just Achilles and a layer of soleus muscle, but otherwise, the internal bone and muscle organization is cut as below:

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The skin at this point is never touched with a surgical instrument, only the subcutaneous later or fascia. Using interrupted absorbable heavy gauge monofilament (single strand of the double looped PDS used for abdominal closure is plenty of suture), interrupted buried sutures are placed in the fascia from middle outwards.

Sketch12684859This closes the fascia and allows the skin to be closed without tension using only occasional interrupted dermal sutures and a running 3-0 or 4-0 absorbable monofilament.

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The skin is dress with a single layer of Xeroform and fluff gauze and gently a compressive dressing is applied from stump to above the knee, while keeping the knee cap exposed -the knee cap is prone to skin necrosis with ACE wraps that are left unattended.

The wound’s ability to heal is now largely a function of keeping the suture line tension and edema free. Edema is the great killer of these flaps and the problem with sutures or staples here is that edema creates zones of skin necrosis under these staples that then results in a postop wound breakdown and infection. With these simple steps largely copied from our plastic surgical confreres, I have been able to create very functional stumps with low morbidity.

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This patient is 3 months from her 2 stage amputation and is walking on her prosthetic leg and is very happy. Notice, the dog ears have contracted!