AMPUTATION
Diabetic foot ulcers are the most frequent cause of amputations. Following a two-decade decrease in the prevalence of lower-extremity amputations, the rates are again increasing, especially among young and middle-aged adults. The increase is reflected in both minor and major amputations (Geiss et al., 2019).
Amputations are most commonly performed to prevent spread of infection and to salvage the remaining unaffected part of the limb. The types of amputations performed include amputation of metatarsal heads, ray resection (when the complete toe is removed), mid-foot amputation, hind-foot amputation, or below-the-knee amputation.
A primary goal is to carry out the lowest level of amputation possible so that the patient can remain ambulatory, with or without a prosthesis, and avoid the need for more surgery in the future. If possible, the surgeon will opt for a partial foot amputation such as ray amputations, transmetatarsal amputations, and Syme’s amputation (removal of the affected foot at ankle level) (WOCN, 2022; Baranoski & Ayello, 2020).
Determining Amputation Type
When deciding on the level of amputation, the surgeon and the wound care team take into careful consideration the circulation status of the extremity. It is essential that there is adequate circulation to the area of amputation to ensure healing post surgery. Ray amputation is required when tissue death has spread within the base of the toes but with limited spread to the patient’s forefoot. A ray amputation will remove the affected toe or toes along with a portion or all of the corresponding metatarsal. Ray amputations usually preserve more function than transmetatarsal (TMT) amputations, but forefoot stability is decreased when more than two rays are removed (WOCN, 2022; Baranoski & Ayello, 2020).
When extensive infection and necrosis has spread to the forefoot, a transmetatarsal amputation will be required. This surgery will leave the patient with a residual limb that can bear weight after wound healing is complete (WOCN, 2022; Baranoski & Ayello, 2020).
When infection spreads beyond the patient’s foot and there is inadequate perfusion, a below-knee amputation is typically performed. If feasible, the length of the patient’s leg remaining below the knee will be in the range of 5 to 7 inches to accommodate prosthetic leg fitting once the surgical wound has healed (AOFAS, 2022).
AMPUTATION INCIDENCE AND MORTALITY
Those with a lower extremity amputation (LEA) due to a diabetic foot ulcer are at greater risk for reulceration when compared with those who receive conservative treatment for an ulcer. In a four-year follow-up review, it was found that 40% of those who had undergone a LEA had experienced reulceration at one year, compared to 30% of those in the non-LEA group. The review also found increased risk for ulceration in both the limb that had the original amputation and the opposite limb, with the former having the greater incidence. A review of patients who had a toe amputation due to a diabetic foot ulcer showed a prevalence of new ulcer development as high as 74.4%.
There is a significant increase in the mortality rates among those who have an amputation related to a diabetic foot ulcer. Data indicates an accumulative mortality rate of 32.7% five years post amputation. The average survival time was 3.8 years, with female patients having a slightly longer period of 4.1 years (Rathnayake et al., 2020).
These figures demonstrate the importance of clinicians working aggressively to prevent wounds reaching the stage where amputation is necessary. However, even with the best care in the world, this is sometimes an unavoidable outcome for many patients.
Preoperative Care
Preoperative care unique to amputation surgery falls into two main areas: ensuring the patient is in the best physical shape possible for surgery and preparing the patient emotionally for the surgery.
Cardiorespiratory status is assessed in close consultation with the patient’s primary care physician and cardiologist, if applicable. Tight glycemic control, along with smoking cessation if the patient is a smoker, will optimize wound healing post surgery. Studies have shown a direct correlation between glycemic control and surgical outcomes. Elevated hemoglobin A1C levels are associated with serious postoperative complications, more frequent ICU admissions, and longer hospital stays (ADA, 2018b).
Patients undergoing an amputation, regardless of the level, are going to be fearful and often shocked and angry that a foot wound could lead to losing part of a limb. The clinician must be supportive, listen, and realize that the patient’s anger is not directed at them personally. The patient and their family will also be apprehensive about what to expect post surgery and how the amputation will affect their lives. The follow-up plan should be discussed in detail with the patient and family and their concerns addressed.
If possible, the patient and family should visit the rehabilitation unit prior to surgery in order to meet with the staff and tour the facility. This helps to alleviate the fear of the unknown.
Regarding the financial burden, the case manager or social worker on the team will act as a liaison between the patient and their medical insurance provider, ensuring that coverage is available for rehabilitation, prosthesis, and adaptive equipment. The patient and family are educated about out-of-pocket expenses and options about how these might be covered.
Postoperative Care
In the immediate postoperative period, monitoring the amputation site for hemorrhaging is critical. Changes in vital signs, such as an increase in pulse rate or decrease in blood pressure, can be indicators of hemorrhaging under the residual limb dressing, along with increase in blood staining on the dressing. These signs should be reported to the surgeon and closely monitored.
Some surgeons prefer to remove the first postsurgical dressing themselves or at least to be present when it is removed so that they can inspect the wound. The incision line is gently cleaned with normal saline and examined for approximation of the skin edges, amount of drainage, and residual limb swelling. Dressing type will depend on the surgeon’s preference or recommendation from the wound care team. It usually includes a noncontact layer over the incision line, absorbent gauze dressings, and stretch bandages to assist with residual limb shaping.
Residual limb positioning post surgery requires special attention to prevent the development of contractures. Patient education focuses on the importance of correct positioning and requires the expertise of physical therapy to provide the most comfortable positioning for the patient. For below-knee amputations, it is advisable to position the knee in extension to avoid contractures; elevating while sitting can help. For above-knee amputations, it is advisable to position the hip in neutral or slight extension to avoid contractures; prone lying is a good option to allowing optimal hip range of motion. Caution is advised when sitting upright to avoid prolonged flexion.
Pain management is an important consideration in the postamputation patient. Studies show that up to 70% of postamputation patients experience pain described as aching, cramping, burning, throbbing, or shooting (INS, 2018). Pain experienced after an amputation can be divided into phantom limb pain (see box below) and residual limb pain.
Residual limb pain is concentrated in the remaining part of the extremity. It can be either superficial and limited to the incisional site, or it can be penetrating pain deep into the tissues of the residual limb. Residual limb pain begins in the immediate postsurgical period and usually disappears with healing; it can also become chronic and persist for years.
Opioids, both oral and intravenous administration, can be used in the immediate postoperative period to treat pain. When using opioids, the prevention of constipation must be considered and may require the provider to prescribe a stool softener or laxative for the patient (Drugs.com, 2018). Other pharmacologic treatments include calcium channel blockers, anticonvulsants, and antidepressants (Amputee Coalition, 2021). In the postoperative period, clinicians perform frequent pain assessment and ensure that prescribed analgesics are administered. A patient in postoperative pain may not be able to optimally participate in self-care activities, learn new skills, or have an optimistic view of recovery.
Patients with an amputation are at high risk for falls, and patient education focuses strongly on safety awareness and training. Patients are instructed not to attempt to get out of bed without assistance, while family members and caretakers are instructed not to assist the patient with transfers until they have received training from physical therapy (Ruff, 2018).
PHANTOM LIMB PAIN
A frequent and often frightening experience for patients post amputation is phantom limb pain, in which they have the experience of pain or an unpleasant sensation in the body part that has been amputated. The mechanism that causes phantom limb pain is not clearly understood, but it is believed that factors in both the peripheral and central nervous system play a role. The descriptors that patients use to describe phantom limb pain include a burning, pricking, or shooting sensation. Patients who have phantom limb pain are found to have an increased risk for residual limb pain, which differs from phantom limb pain in that it is felt in the residual limb (Zhou, 2019).
Medications used to treat phantom limb pain include tricyclic antidepressants and anticonvulsants; nonpharmacologic treatments include acupuncture and nerve stimulation.
The use of a mirror box is a novel idea for treating phantom limb pain, based on the concept of body perception and brain mapping of integral parts of the body. Updating body perception depends a great deal on tactile information from parts of the body, however after an amputation, this input is lost and the “brain map” is trapped in the perception that existed prior to the amputation. It is thought that phantom pain occurs because patients believe that the limb is held in an awkward, painful position that they cannot rectify.
The basis behind the mirror box is that it appears as if the amputated limb still exists. The mirror box has two openings—one for the intact limb and one for the residual limb. The mirror allows the patient to see a reflection of the intact limb, creating the visual input that both limbs still exist. The patient performs movements and observes the intact limb moving while imagining that the amputated limb is moving. The brain is tricked into believing that the missing limb is being moved into a pain-relieving position. Instructing a patient in the use of mirror box therapy is done by a PT or OT who is familiar with this treatment modality. Research has shown that it is effective in relieving phantom limb pain (Zhou, 2019).
Using a mirror, the brain is “tricked” into seeing two limbs. (Source: © Sköld et al., 2011.)
Follow-Up Care
In the weeks following the amputation, the clinician continues to monitor for healing and decreased swelling in the residual limb. Edema can often present a problem. Compression residual limb shrinkers and bandaging help to provide good edema control.
During this time, the patient and family will continue to receive emotional support. Patients frequently have a difficult time looking at the amputation site and may require encouragement to participate in their own care.
Delayed healing is a problem for patients with diabetes, especially if there is associated peripheral vascular disease and decreased circulation to the amputation site. During follow-up appointments, clinicians monitor the wound closely for signs of delayed healing and infection. Dehiscence (separation of the wound edges) is another major concern post amputation.
There may be a considerable period of rehabilitation when the patient requires interventions from multiple disciplines—including nursing, physical therapy, and occupational therapy—to maintain safety, mobility, and assistance with self-care.
It is important to ensure that the patient is in the best physical condition possible for a future prosthesis fitting. Limb wrapping and using an elastic shrinker sock are essential to preparation for prosthetic fitting. Physical therapists are specialists in this area of care and will guide other team members in correct residual limb management.
Referral is made to a dietitian if there is a concern about malnutrition or poor appetite.
Prosthetic Care
The timing for prosthetic fitting depends on how quickly the wound heals. In most instances, fitting begins somewhere between eight weeks to six months post surgery (Amputee Coalition, 2021).
Statistics indicate that 90% of those who have a partial foot amputation will be able to use a prosthesis and maintain their mobility. For those with a below-the-knee amputation, the figure drops to 75%, and only 25% of those with an above-the-knee amputation will be successful with a prosthesis and independent mobility (WOCN, 2022).
A prosthetist is involved early on in the patient’s postoperative care and assists in preparing the patient’s residual limb for fitting and educating the patient in the care of their new prosthetic device. Physical therapists help the patient learn to walk safely with an artificial limb, develop a training program for the patient, and monitor their progress. Patients are also instructed on how to apply prosthetic socks and liners correctly, to change them daily (at a minimum), and to wash them following manufacturer recommendations.
Clinicians must be aware that the residual limb is at high risk for ulceration, and many times this is preceded by callus formation. All disciplines are therefore involved in careful monitoring of the residual limb to ensure that it is tolerating the new prosthesis and that there are no areas of redness that might indicate undue pressure. If redness does occur, the prosthetist is informed immediately and adjustments made to the prosthetic fit.
Since a major amputation also puts the contralateral extremity at greater risk for ulceration, suitable footwear and education to prevent ulceration must be focused on the remaining foot.
Reintegration into Normal Routine
Getting back to normal life or defining a new normal can often be difficult for a patient after an amputation. The stressors patients face include medical expenses, whether they will be able to return to work, whether they will be permanently disabled, how their family and friends will react, and how they will cope personally with an altered body image.
Losing part of one’s body damages body integrity and can have a serious negative impact on a patient’s physical and psychological condition. Those who undergo an amputation can experience feelings of grief, depression, and anxiety, but data indicates that the incidence of depression decreases as time passes after an amputation (PAM Health, 2021). All members of the wound care team are involved in helping the patient cope with changes in body image, with clinicians’ acceptance and respect for the patient as “a whole person” providing a positive image. For patients who exhibit severe denial or depression, referral to a mental health specialist is advisable.
Physical therapists and occupational therapists provide valuable input on workplace ergonomics and assistive devices needed to maintain employment. Several studies have shown that interventions from these therapists result in:
- Decreased risk of complications post amputation
- More successful reintegration into society
- Better emotional health
- Greater patient acceptance of the amputation
- Greater protection of the residual limb
- Increased well-being as a wheelchair user
Other studies have found that patients participating in inpatient rehabilitation had higher levels of mobility one year post amputation compared to patients who did not receive inpatient therapy. Occupational therapy plays a critical role in advanced prosthetic training, instructing the client on how to incorporate the prosthetics into more complex activities, such as home and work activities, driving, sports, and recreational activities. Occupational therapists will also be involved in community reintegration of patients (AOTA, 2021).
A case manager or social worker on the wound care team can assist the patient with insurance claims and disability benefits.
CASE (continued)
Mr. Hernandez has missed several appointments at the wound clinic since his wife was ill and he had to put in extra hours at work. When he does return to the clinic, he looks tired and ill.
On examination, the clinician finds an ulcer on the plantar surface of his left foot. The clinician performs a full wound assessment, noting greenish drainage, a malodor that persists after the wound is cleaned, and redness and swelling in the tissues surrounding the wound. When she inserts a sterile applicator into the wound, she is able to probe down to bone.
The physician takes a deep-tissue biopsy from the wound, orders an immediate X-ray, and starts Mr. Hernandez on a broad-spectrum intravenous antibiotic. He also requests that Mr. Hernandez be scheduled for vascular studies to determine the circulation status to his lower extremities.
Mr. Hernandez becomes confused and angry, stating, “All these tests are not needed! It’s just a little wound. My wife is putting iodine on it at home.” The clinician explains to Mr. Hernandez that, although on the surface of his foot the wound appears to be small, it goes the whole way down to the bones in his foot and that tests are needed to ensure that there is no bone infection. Mr. Hernandez reluctantly agrees to the X-ray but states he doesn’t know whether he can come to the outpatient clinic to have IV antibiotics due to his work schedule. He insists that there is no need for vascular studies.
The wound care team also broaches the subject of off-loading with Mr. Hernandez and explains at length to him why it is so important. He responds that he has to work and has to wear his boots.
It is apparent that Mr. Hernandez is not only confused by what is happening, but he is shocked and afraid. It is hard for him to understand that a little hole in the bottom of his foot could be putting his whole limb at risk. However, the wound care team has in the past built up good rapport with Mr. Hernandez, and maintaining that level of trust is important at this stage.
Since Mr. Hernandez insists on continuing to work, the team considers what options are available for off-loading his foot. Off-loading is vital to healing, but it also has to fit in with Mr. Hernandez’s choices about his life. The team decides that a felt foam dressing is the best option. Mr. Hernandez’s work boots will accommodate the dressing without causing extra pressure to his foot. He will also be advised that when he is not working, he should rest with his feet elevated.
IV antibiotics are also determined to be essential. Once the tissue culture results are ready, Mr. Hernandez will be switched to the appropriate antibiotic to target his infection. The physician will schedule a consult with an infectious disease (ID) specialist, and the case manager will look into scheduling the patient’s IV antibiotics around his work schedule and the ID consult. The team also decides that the best course of action is to revisit the question of vascular studies and a vascular consult once Mr. Hernandez is established with the IV antibiotic therapy schedule and after he has seen the ID specialist.