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All,
I have to agree 100% with SwatSurgeon. His posts are very sound advice to all who need to perform an amputation. Never crush tissue. Sharp excisions. Neuroma development is a bad complication of this operation and we do everything we can to avoid it.
The goal is quite often to get the limb off as result of a trauma secondary to massive hemorrhage (life over limb) or to treat the infection that could consume the patient's life (sepsis due to pus or necrotizing fasciitis). Many times in the older diabetic patient or the patient that has had prolonged ischema to the foot (diminished blood flow) has also developed neural pathways, we believe , in the brain that must be overcome so that after amputation, the phantom pain is eliminated or diminished. This is why a spinal or epidural catheter that takes away the pain for hours to several days prior to an amputation can be important. The problem is that most traumatic amputations or massive forefoot / diabetic foot infection require an amputation emergently or urgently. If the pain has occurred for weeks to months, and the pain neural pathways have matured, the results is post-op phantom pain. For traumatic injuires, many times patients are dying so, we do what we need to do emergently (again, life over limb). Nerve blocks and epidurals are excellent modalities but if you are dying, we need to get you into the OR and asleep to get the work at hand completed.
Now, as for technique, use a scapel and sharply cut the nerve. Do not use a scissors. Suture ligation of the end of the nerve which is key prior to the cut. Make sure that the nerve retracts up into the muscle. You do not want a nerve below the level of the amputated bone as the nerve wil be crushed by the weight between the cut stump and the muscle when the prosthesis is eventually used. I add a mixture of 1/4 percent Marcaine with 2% lidocaine to the area around the cut nerve. I do not inject straight into the nerve, just the tissue around the cut end. Neuromas are the enemy which is why we ligate the end and sharply incise the nerve.
Think about an epidural, however, that is if the patient is stable, and not in severe ARDS so they can be up on their side to place an epidural, and not on anticioagulation such as heparin, low-molecular weight heaprin, asparin, plavix or coumadin in the immediate post-operative period. Most patients should not be on these medications or should have had their coags corrected with fresh frozen plasma pre-op. If in an ICu or even in a theater of war, lovenox subcutaneous may be started for DVT's if indicated, and if that occurs, I would not place an epidural as there is the risk of spinal cord hematoma and paralysis. Coagulation studies should be normal before an epidural is placed. Now, as an adjunct, I have found neurontin to be effective with many pain syndromes, especially post-operative pain in burns, trauma and in my vascular patients after amputations. This is also true for our phantom pain patients.
I am going to ask our Rehab physician what he uses in the prosthetic clinic for phantom pain. I will ask him on Monday and get back to all of you as this is an important topic and is often poorly understood and many physicians either do not know what to do or get angry when this happens and blame their patients (this is why the vascular surgeons, pain specialists, and rehab physicians are the best to discuss this as they see so much of it). However, it has been my experience that the best way to treat phantom pain is before it even starts and that is why epidurals for a few days pre-op can be beneficial for patients, to re-educate the brain and deny it the (painful) neural input it had been dealing with previously. However, for the soldier, sailor or marine in the field with a severely mangled extremity, this would not be possible For more information, I might recommend Rutherford's textbook in Vascular Surgery. The chapter on causalgia is quite good when I read it several years ago.
More to follow . . .
Dutch
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