Health & Disease Info
All You Wanted to Know About ... Amputation

This booklet is prepared to provide you with an overview of the spectrum of amputation surgery commonly performed by general and vascular surgeons. Amputation actually is the oldest form of surgical treatment with the first known prosthetic appliances for amputees being dated back to approximately 300 B.C. Today amputation is a last resort.

Indications for Amputations
The need for amputation represents end stage disease. This is disease where we are unable to correct or combat the ravages of the disease process which precipitates the need for amputation. As vascular surgeons, our most common precipitating factor is poor circulation. By poor circulation we are talking about arterial obstruction which leads to rest pain or gangrene. The obstruction must be so severe that reconstruction is either not possible or it would have such a low chance of limb salvage that amputation is considered as an alternative to it.. If an arterial tree is able to be reconstructed, it is our preference to proceed with revascularization whenever possible. When reconstruction is not possible and symptoms lead to pain at rest so that that patient has difficulty eating, sleeping, or carrying out his normal daily activities, or when gangrene or actual death of tissue occurs, amputation becomes the only viable alternative in restoring function and comfort.

The next most common cause of amputation is overwhelming infection. In an ischemic extremity (a leg with poor arterial circulation) infection can become very severe very rapidly. It does not take much blood supply to maintain the integrity of the skin. However, once the skin is damaged, infection has a portal of entry and with restricted blood supply there is a severely diminished ability of the body to fight infection. For this reason a very minor wound can lead to a significant overwhelming infection in a very short length of time. A very similar mechanism is present in the formation of diabetic foot infections because of the changes in the blood vessels seen with diabetes mellitus. Once infection is present in the soft tissues it will often spread to the boney structures causing what we call osteomyelitis, which is an infection in the bone itself. In a very ischemic foot or of the foot of a diabetic patient, it is almost impossible to clear osteomyelitis once it has become established. This is because regardless of how high the levels of antibiotic we can obtain in the blood stream, the poor circulation and the blockage of profusion in the foot makes it almost impossible to get a satisfactory level of antibiotics to the site of infection. Early aggressive treatment of infected feet can many times avoid the need for amputation or at least minimize the extent of amputation required.

In a foot with very poor sensation, one of the most common causes of infection is a neurotrophic ulcer (or an ulcer which forms because of repeated trauma) which is unable to be appreciated by the patient. While many neurotrophic ulcers will heal with avoidance of pressure and appropriate orthotics,(special shoe paddings), it is sometimes necessary to perform limited amputation in the area of the pressure in order to avoid the need for amputation of the threatened foot.

Other reasons for the need to amputate would be represented by trauma, particularly if a traumatic infection with gas gangrene were to ensue. Finally, a chronic nonfunctional deformity or poor wound healing with recurrent breakdown might also require a limited amputation for restoration of function.

Choosing the Level of Amputation
The first step in planning for amputation is to determine the level of amputation that is required. In determining this there are several requirements which must be taken into consideration. First of all we must remove all infected, necrotic, or painful tissue. Then we must preserve a functional stump for application of a suitable prosthetic device. Finally, we must be sure there is an adequate blood supply sufficient for healing of the wounds. We make all efforts to try to perform amputation as far distally as possible (taking as little tissue as possible from as far away as possible). The reason for this is very simple. When amputation is performed at or below the ankle level there is very little functional disability and very little in the way of increased energy requirements for ambulation. When major amputation is required either at the below knee or above knee level, there is a marked increase in the energy requirement. With a below knee amputation the increased energy requirement for ambulation is 10 to 40%. With an above knee amputation this increased energy requirement is in the range of 80 to 120% above normal. Crutch walking without a prosthesis results in at least an extra 60% increased energy requirement. The success or failure of amputation at almost any level is critically dependent upon the blood supply at that level. For that reason there are several objective ways of determining the adequacy of blood supply so that primary healing can take place. While we want to amputate as little as possible we also want to obtain primary healing, and it does no good to do a more distal amputation when it has very little chance of healing.

Circulation Criteria
The first circulation criteria that we use is the development of dependent rubor (or the redness that develops on the foot when it hangs in a dependent position). If skin develops dependent rubor, this is a sign that the skin is clearly ischemic and primary healing will not take place in this situation. Therefore, dependent rubor is an absolute contraindication to amputation at that level.

The second circulation criteria that we use is lower extremity doppler examination, which is a good prognostic test with many studies having been done to confirm the criteria set out for this study. When there is a doppler pressure of 70 mm. of mercury at the ankle and evidence of a pulsatile pulse volume recording at the midfoot level, 85% of all transmetatarsal amputations will heal. When there is a doppler pressure of 65 mm. of mercury and pulsatile pulse volume recording at the below knee position the vast majority of below knee amputations will heal. When there is a direct popliteal pressure of 50 mm. of mercury or greater at least 80% of below knee amputations will heal. However, if the doppler pressure is less than 50 mm. of mercury only 30% of amputations will heal at the below knee position. An exception to the doppler pressure criteria is in patients with diabetes mellitus whose pressures are often artifactually elevated secondary to the deposition of calcium in the blood vessels making them difficult to compress.

The third criteria that we use is photophlethysmography. A photoelectric cell is placed on the toes or at the midfoot level to measure pulsation of blood flow in that area. Positive digital pulsations correlates with a 90% chance of healing of a digital amputation in the absence of infection. This particular technique is quite useful in determining the probabilities of healing for transmetatarsal and digital amputations.

The fourth criteria that can be used is transcutaneous oxygen values. This is a new technique which promises to be quite useful but is still somewhat experimental. We are keeping a close eye on developments in this field and will incorporate it into our evaluations once reliable criteria have been developed.

Specific Levels of Amputation

1. Toe
This is the most common level of amputation. The indications for amputation at this level include ulceration, osteomyelitis, gangrene, infection, and severe deformity. Digital ulcerations occur quite frequently in diabetics leading to osteomyelitis. As stated before, the chances of curing digital osteomyelitis with antibiotic treatment in a diabetic are very poor. In the case of a severely ischemic foot (one with poor circulation) gangrene may develop on a single digit. There is an alternative to surgical amputation in this situation in that alcohol dressings can be applied to that digit causing the tissue to become desiccated and quite dry. Autoamputation will often occur with healing below the level of the gangrenous digit and surgical intervention is often not required in this situation. As long as infection does not intervene, we can many times allow nature to take its course with just simply alcohol dressings as the only treatment offered. Circulatory criteria used to determine if amputation at the digital level should be successful includes the following:

1. Absence of dependent rubor.
2. A venous filling time of less than 20 seconds
3. Ankle doppler pressure greater than 70 mm. Hg.
4. Good digital pulsation on PPG testing.
5. There can be no cellulitis or evidence of infection proximal to the incision site.
6. There can be no involvement of the MP joint (toe to foot joint) or involvement of the metatarsal bone ( one of the foot bones). The presence of ankle pulse is a good prognostic sign for healing.

Technically the amputation is quite simple. A circular incision is made around the base of the toe and amputation is accomplished through the proximal bone in the toe. These amputations generally heal quite nicely and a good cosmetic result is obtained. The only prosthesis required would be a small piece of foam to act as a spacer so that the digits on either side of the amputated one do not deviate to fill in the space.

2. Ray Amputation
This amputation has the same indications as were discussed under amputation of the toe. However, the disease process crosses the metatarsal phalangeal crease (the crease at the base of the toe) or involves the metatarsal head. Contraindications to this procedure is disease proximal to the incision or lack of acceptable circulation criteria. Advantages of this type of operation are minimal deformity with good rehabilitation potential. No prosthesis is required for any of the toes in the middle of the foot. Indeed, once healing occurs one many times has to count the toes to be able to tell that one is missing. Of course if the great toe requires amputation, a small filler type prosthesis is required to keep the foot from drifting in a shoe. Disadvantages of this technique are mostly due to resection of the first metatarsal head which is a primary weight bearing surface and resection causes problems with gate imbalance. Other disadvantages include the risk of hematoma formation, nonhealing, secondary infection, and the development of chronic osteomyelitis in the remaining bone. The technique is rather simple with a racket type incision extending around the toe and onto the dorsum (top) of the foot over the metatarsal head. Resection is done through the distal metatarsal shaft with or without primary closure of the wound.

3.Transmetatarsal Amputation
This is an amputation across the midfoot level. The indications for it are gangrene or infection involving several toes or extending proximal to the metatarsal phalangeal crease, but still in the distal third of the foot and on the dorsum of the foot only. The plantar surface (or the bottom of the foot) must remain completely intact since the distal line of resection is just proximal to the base of the toes. Contraindications to this type of amputation are deep forefoot infection or cellulitis and lymphangitis extending up the foot or leg, or involvement of the plantar skin proximal to the MP crease. Advantages to this amputation are that the results are functionally good with minimal disability and a simple prosthesis is all that is required. This usually takes the form of some molded foam in the toe of the shoe. Disadvantages are a high incidence of nonhealing, hematoma formation, and infection which result in necessity for conversion to a higher amputation. Technically the amputation is accomplished through an incision that goes across the dorsum of the foot at the distal one-third to middle one-third junction. The incision is then carried down on the sides of the foot and then distally so that the plantar surface is transsected just proximal to the toes. All bones are transected in the midfoot level and the plantar skin is then folded upwards over the end of the bones and sutured to the dorsal skin.

4. Syme Amputation
This is the next level of amputation proximal to the transmetatarsal position. The indications are basically the same as those for a transmetatarsal amputation. However, the process involves more of the forefoot area or involves the plantar surface. Contraindications are any involvement of the heel or the ankle with an infectious process or evidence of gangrene or ulceration in this area. Another contraindication would be a neuropathic foot (one that does not have good sensation) especially in the patient with diabetes mellitus. Advantages of this amputation site is that it is very durable because it is an end-weight-bearing stump with the skin of the heal which was designed to support weight on the distal surface. There is minimal disability and minimal increase in energy requirement. Disadvantages include delayed healing and complications of hematoma and infection. There is a significant ankle deformity secondary to redundant skin, and this may even require a second operation to correct this deformity. A prosthesis consists of a foot in a plastic shell which incorporates the lower leg and extends up toward the calf. The amputation is accomplished through an anterior incision just about at the level of the ankle crease which is carried down on each side of the foot to just in front of the heel where the incision traverses the plantar surface of the foot. The incision is deepened through the joint and all bones of the foot are removed from the heel skin and soft tissue pad. The ankle bones are cut off flush with the bottom of the tibia. The skin of the heel is then sewn to the ankle crease and drains are placed in position. Dressings are applied to keep the heal skin in position to bear weight. This process causes a very bulbous stump with skin flap or dog ears on each side. There is a significant incidence of hematoma formation and secondary infection. The patient must remain nonweight bearing on the stump for at least one month postoperatively.

5. Below Knee Amputation
This is the most common level of the major amputation sites. If the syme amputation at the ankle is not possible, then preservation of a long lower leg stump is not advantageous. The weight is born within the prosthesis on the patellar tendon (which is the tendon which extends down from the knee cap to the tibia) so that basically as the prosthesis is worn weight bearing is by kneeling on the supports within the prosthesis. The length of the stump has to be balanced between keeping it long enough to be able to swing the prosthesis back and forth with as little difficulty as possible, and at the same time keeping it short enough so that it is not difficult to fabricate a prosthesis to accommodate the stump within it. The main indications for below knee amputation are a disease process extending to and including the ankle or a circulatory status that is unsatisfactory for more distal amputation to heal primarily. Contraindications for below knee amputation include gangrene or infection in the midthird of the leg, unsatisfactory circulatory status, not meeting the criteria for healing at a below knee position, a flexion contracture of the knee (or permanent bending of the knee), an occluded profundofemoris artery, or a stroke or neurologic dysfunction on the side of the proposed amputation so that effective use of the below knee prosthesis would be impossible and ambulation is not a realistic goal.

Advantages of a below knee amputation include superior durability and a good chance of healing and excellent rehabilitation potential. Ninety percent of patients with below knee amputations are able to learn to ambulate independently. Disadvantages of below knee amputation are minimal if a more distal amputation can not be performed. A technique of below knee amputation includes an incision made anteriorly 5 or 6 inches below the knee and tailored so that posteriorly it goes distally on the leg far enough to include most of the muscle mass of the calf. After the bones are cut the posterior flap is reflected forward to close the wound and cover the end of the bones. The stump is well padded and a plastic cast is applied. The next day a pylon with a foot attached is added to the cast forming a temporary, immediate fit prosthesis. Ambulation training then begins. However, no weight is placed on the amputated leg. This is simply "touch down" to provide balance. Three weeks later the cast is removed as are the staples from the wound, and a temporary prosthesis is made. Weight bearing is then begun. The weight is born on the tendon below the knee cap or the patellar tendon. Once the stump shrinkage is complete a permanent prosthesis can be fabricated.

The purposes of the initial cast are multiple. It controls edema or swelling in the stump. It prevents flexion contracture (a fixed bending of the knee that can not be straightened). While doing all this the cast also promotes healing.

There is an unusual situation in which a two stage amputation is required. If there is overwhelming infection in the foot which has cellulitis and lymphangitis extending above the ankle joint there is about a 25% incidence of infection in a below knee stump if below knee amputation is primarily performed. In this case it is better to perform the first stage of amputation at the ankle level leaving the wound open so that the infection can drain out of it. We then proceed with the second stage of a definitive below knee amputation. If all circulation criteria are met in doing a below knee amputation there should be about an 80% chance of healing. Over ninety percent of these patients will be able to learn to ambulate independently.

6. Above Knee Amputation
There are actually three levels of above knee amputation which can be performed. The low and mid levels function very nicely with prosthetic devices. However, the high above knee amputation leaves a stump that is so short that it is really not effective in controlling the prosthesis. Indications for above knee amputation include:

1. Inadequate blood flow for a more distal amputation.
2. A disabled patient not expected to be able to walk again.
3. Profound life threatening infection and questionable viability of the leg.
4. Infection or gangrene precluding a below knee amputation site.

Contraindications for each level of above knee amputation include extension of the gangrenous process or infection to the level of the proposed amputation site or severe necrotizing limb infection which would have a high incidence of resulting in an infected stump. Advantage of above knee amputation is greater than 90% primary healing rate. Disadvantages, however, are that only 40 to 50% of above knee amputation patients can learn to ambulate independently. There is a large increased energy requirement amounting to 80 to 120°!o greater than normal. The technique is quite simple with a circular incision. The bone is cut short so that the muscle can be closed over the bone prior to closing the skin. All nerves are also cut under tension so that they retract and are not present in the end of the wound. Prosthesis is an Ischial weight-bearing prosthesis. In other words, the weight is born on the buttocks and you actually sit on the prosthetic.

7. Hip Disarticulation
This is the most radical of all amputations and is rarely done by a vascular or general surgeon. Indications are severe circulatory insufficiency, overwhelming infection, tumor, trauma, or need for amputation in a patient with either a failed hip reconstruction or a metal hip prosthesis. There are no contraindications as long as amputation is not possible below the level of hip disarticulation. The advantages of this position is that just about all will heal. Unfortunately less than 10% of patients will ever be able to learn to walk. The prosthesis is a pelvic bucket and the energy requirement is at least 11/2 to 21/2 times normal energy requirements.

Complications
Complications following amputation procedures can include any of the following which are seen in measurable incidence and others which are rarely associated.

1. Pain
This takes the form of phantom limb pain where the amputated part continues to feel like it is present. There is a variable incidence from 5 to 80% reported to different series. The phenomenon seems to be associated with the length of time that the pain was present preoperatively so that it appears to be an "afterimage" type effect. Phantom limb pain is also associated with the amount of edema that develops following amputation. Rigid dressings and tight elastics seem to reduce the incidence of this- phenomenon. Aggressive rehabilitation and early prosthetic use also decreases the incidence of phantom limb pain. There is no specific treatment for it that is universally reliable.

2. Death
The incidence of mortality increases with the level of amputation progressing more proximally. With minor amputations having an incidence close to zero mortality fog below knee amputations is reported between 3 and 10%. Mortality for above knee amputation occurs in 20 to 40% increasing dramatically in patients above the age of 70. Two-thirds of all postoperative deaths are due to cardiovascular complications including heart attack, stroke, congestive heart failure, and poor circulation to the bowel or kidneys.

3. Nonhealing
This has a variable incidence of 10 to 30%. It is usually associated with poor circulation, hematoma formation, or secondary infection. It is often also seen following trauma to a previously normally healing stump reflecting the fact that a recent amputation needs to be protected from further injury. Failure to heal invariably requires a higher level of amputation.

4. Stump Infection
This also has a variable incidence of 10 to 30°l0. It is directly related to distal infection. It is also associated with poor skin healing secondary to circulatory problems and hematoma formation. Once infection is present the wound must be opened and drained usually requiring revision to a higher amputation level.

5. Deep Venous Thrombosis and Pulmonary Embolus
Blood clots in either the amputated extremity or the other leg occurs in up to 40% of patients. In some series it is associated with the level of amputation, increasing in, incidence with the more proximal amputation levels. Prophylaxis through anticoagulation is relatively contraindicated . It is believed that this can cause a higher incidence of hematoma formation which can lead to wound breakdown and infection. The best prophylaxis against blood clots is ambulation both before the amputation occurs and early ambulation and rehabilitation following amputation. Maintenance of good hydration (fluid status) also lowers the incidence of blood clots.

6. Pneumonia
This is associated with prolonged inactivity and poor mobilization. It occurs mostly in debilitated patients.

7. Flexion Contractures
These can happen at the knee or hip level and are best prevented by early physical therapy and range of motion exercises.

8. Renal Insufficiency
This complication is seen simply as a reflection of the severity of disease in the vascular tree causing the amputation to be necessary. We will discuss the potential complications with you in greater detail if surgery is recommended. Of course, you should feel free to ask us any Questions you have concernig the surgery, alternatives and the potential complications.

Postoperative Recovery
Recovery following amputation occurs in stages. The immediate postoperative pain is usually relieved within about three days. Rehabilitation starts in the hospital for all amputation patients. Those with minor amputations are taught to ambulate with crutch walking or a walker. They must remain nonweight bearing on the amputation site until it shows evidence of adequate healing. This will be determined in subsequent visits. For those patients with major amputations, particularly above and below knee amputations but also sometimes with patients with syme amputations, we will recommend that the rehabilitation program that is started in the hospital be continued at a rehab center. The more aggressive the rehabilitation program, and the more rapid ambulation is accomplished, the better the results will be following amputation.

Prosthetics
The patient undergoing syme amputation or amputations at a higher site will require a prosthesis to aid ambulation. We will help you find a convenient and effective prosthetic maker who will work with you to fit a custom made appliance for your needs.

Patients undergoing toe, ray, or transmetatarsal amputations will require more simple orthotics. These may be obtained from any of these orthotic makers or also from a number of the podiatrists in town. Once the wounds are healed and edema is reduced to a baseline level, you will be referred for any orthotics that may be required. For other special needs after your surgery there are a number of home health supply companies in the area. They are listed under hospital equipment and supplies in the yellow pages of the telephone directory and are too numerous to be listed here. These companies can help you with walkers, crutches, wheel chairs, special chairs, hospital beds, etc. Before making arrangements for any of this equipment, please discuss your needs with your doctor so that you do not order supplies that you do not really need.

Rehabilitation
Ultimate rehabilitation is a combination of many variable factors. Probably the most important factor in determining speed and completeness of rehabilitation is the attitude of the patient. A positive attitude towards rehabilitation and an aggressive approach towards the goals of rehabilitation will be rewarded with a high degree of satisfaction. The ultimate goal of rehabilitation is independence. Numerous studies have shown that an aggressive approach towards rehabilitation, the use of rigid dressings or immediate fit prosthesis in combination with positive patient attitude have lowered the time required to obtain independence. Rehabilitation may be as little as one month when compared to other less aggressive techniques which require an average of four months or more for independent ambulation.

We have prepared this booklet to try to help you understand the factors that we must consider in treating your particular problem. As stated previously, our initial approach would always be to try to restore circulation to as close to normal as possible and avoid amputation whenever possible. However, when this goal is unrealistic either because of the extent of your disease or the effects of concurrent disease in other areas, then amputation may become necessary. We hope the information presented here will help you to understand the factors that we must take into consideration in making a recommendation to you. We feel that well informed patients are able to cooperate more fully with recommended treatments, and this will lead to a smoother more complete recovery. If you have any problems or questions during your convalescence, please don't hesitate to call our office at . Please be sure to keep all appointments so that we can monitor your recovery and help your recovery be as speedy and complete as possible.