Overview of Forearm Amputation
A forearm amputation is a type of surgery that falls under the category of upper limb amputations. This surgery, which involves removal of the forearm from the elbow to the wrist, is the most common type of upper limb amputation. The main reasons this surgery is needed are injuries, infections, problems with blood vessels, and cancer.
Injuries leading to amputation can happen in different ways. In civilian life, they’re mostly caused by severe accidents at work, like getting a limb crushed by machinery. In the military, they can be due to injuries sustained in combat, or from explosives.
Using a prosthetic limb after the surgery, and choosing to amputate at the wrist level instead of closer to the body, are key to better recovery. A range of specialists can be involved to improve recovery as well. Early fitting of the prosthetic limb can speed up the return to daily activities. Psychological therapy can help cope with the emotional impact of the amputation. And physical and occupational therapy can help learn to live with and use the prosthetic arm.
Anatomy and Physiology of Forearm Amputation
Arm amputations near the elbow require doctors to have deep knowledge of the bones, muscles, nerves, and blood vessels in the region. They also need to know about the body’s soft tissues to make sure any necessary reshaping of tissues, relocation of muscles or tendons gives the best possible outcome for the patient. In this discussion, we’ll focus on nearby structures.
When doctors perform a trans-radial amputation, which is an amputation that happens across the radius bone in the forearm, their goal is to keep as much of the limb as possible. The length of the remaining portion of the arm is directly connected to how much rotation – turning the palm up or down – can still happen. This is an important feature for the ability of the limb and any future prosthetic (artificial limb) to be operational. The amount of rotation can range from the full motion at 120 degrees for wrist disarticulations – where the wrist is entirely separated, to none for very short remaining limb lengths.
The structure of your forearm includes two main bones – the radius and the ulna. Twenty different muscles connect to these bones, and they are grouped into two areas – the front (which assists in bending and rotating the palm down) and the back (which helps with straightening and rotating the palm up). Two of the muscles important for bending the elbow – biceps brachii and brachialis – attach to these two bones. If the patient has a short amputation, there’s a procedure where the biceps tendon (a strong connective tissue that connects muscle to bone) is relocated from the radial tuberosity (part of the radius bone) to the ulna which can help increase function.
In terms of the body’s wiring, three main nerves (ulna, median, and radial nerves) are involved in sending signals to your forearm. The median nerve powers the muscles that help in bending the fingers and thumb. The ulna nerve controls the muscles that bend the wrist and fingers, while the radial nerve is responsible for the muscles that straighten the fingers and thumb.
The skeleton structure is an essential factor for the functionality of the remaining limb after an amputation. However, sometimes the covering of the amputated area with skin can be challenging, depending on the reason for the amputation. In these situations, procedures to move healthy skin, muscle, or other tissue (flaps) from another area to cover the cut end of the arm might be needed.
Why do People Need Forearm Amputation
Forearm amputations, or the removal of the arm below the elbow, aren’t common. However, when they’re needed, it’s usually because of injury, an illness, or a birth defect. By far, the most common reason is trauma (about 80-90% of the time), especially in cases of serious crushed injuries caused by accidents at work. Occasionally, the forearm may have to be removed if it’s substantially damaged, or if the blood supply suffers an injury that cannot be fixed. Extensive burns, severe frostbite, or electrical injuries could also necessitate this procedure.
Various illnesses, both sudden and long-standing ones, could also give rise to the need for a forearm amputation. A significant cause is an infection—a rapidly advancing one like necrotizing fasciitis, rather than slower-progressing infections seen in the lower limb such as osteomyelitis. If an infection makes an upper limb useless and spreads toxic substances into the rest of the body, amputation might be carried out to save the patient’s life.
There’s no formal grade of injury severity to decide whether an amputation is needed. It’s usually left to the surgeon’s expert judgement. For instance, in cases where a patient has an overwhelming infection (systemic sepsis), amputation could be necessary to get the infection under control. Blood vessel complications stemming from conditions like peripheral vascular disease or diabetes might also warrant the removal of a limb in their advanced stages.
In some rare cases, a nerve injury in the upper limb might cause uncontrolled sores (trophic ulcers) in an area that’s lost all sensation. However, amputation isn’t typically done for people with paralysis in all four limbs (quadriplegia).
Forearm amputations might also be necessary if there’s a cancerous tumor that hasn’t spread to other parts of the body, or if the limb is deformed from birth. Less commonly, it may be required in other scenarios such as severe muscle or joint contractions that limit movement (contractures).
When a Person Should Avoid Forearm Amputation
The only absolute reason not to amputate a limb is if preserving the limb or part of it would be better for the person’s function. The decision to keep a limb depends on several things: how well the person can feel touch and pain, how well they can move the limb, how much pain they’re having, and what the person needs the limb for. This decision is always focused on what would work best for the person’s daily activities and quality of life.
Who is needed to perform Forearm Amputation?
A number of medical professionals work together to carry out a forearm amputation. The team includes a specialized doctor, known as either a general or an orthopedic surgeon, who is trained to perform this type of surgery. Next, a vascular surgeon is often needed, who is an expert in doing surgical procedures involving blood vessels. They work together to make sure that the amputation is done correctly and safely.
Assisting them are the scrub nurse and the rotating nurse. The scrub nurse is tasked to prepare the surgical tools and hand them to the surgeons during the operation, while the rotating nurse ensures the smooth flow of the surgery by managing the activities around the operating room.
Lastly, the OT (Operating Theatre) technician is also essential. They are responsible for setting up the technology and equipment used during the operation. All these experts work together to ensure patient safety and a successful surgery.
Preparing for Forearm Amputation
Before an amputation procedure, it’s important to know if the surgery is scheduled (elective) or due to a sudden injury (traumatic). In emergency situations, doctors follow guidelines called Advanced Trauma Life Support (ATLS), which centers on identifying and treating the most life-threatening injuries first, which might even be the damaged limb that needs amputation. Once the patient’s condition is stable, two senior doctors must agree on the decision to amputate. The patient’s consent is also necessary. In such an acute case, it’s usually preferable to gradually remove damaged tissue (a process called debridement) and then close the wound at a later time.
The main goal of an amputation is to preserve as much length of the limb as possible for better functionality. The severity of the injury and how much healthy skin is available can determine this. Doctors assess the health of the important structures in the limb, including how well the muscles, bones, and major nerves in the forearm are working. Ensuring a good blood supply to the healing area – the stump – is crucial, especially if skin flaps are going to be used to cover it afterward. The condition of the blood vessels is essential in determining the amputation level.
In planned amputations, the same principles generally apply; however, doctors can prepare better. For instance, they can insert peripheral stents (tubes to keep blood vessels open). It’s also important for this process to get the patient in the best possible condition before surgery.
The team for the amputation usually includes various specialists such as vascular, general, orthopedic, or plastic surgeons. Plastic surgeons are particularly essential for covering the stump with skin flaps, so they should be involved early in the process. Patients may also need intensive or high-level post-surgery care. Engaging psychologists, physiotherapists, and occupational therapists from the start can help enhance patient outcomes.
Lastly, on rare occasions, amputations might be required for birth defects (congenital deformities) or in the case of severe muscle tightness (contractures).
How is Forearm Amputation performed
For the surgery, you will be laid flat on your back in a clean operation room with your arm stretched out on an arm table. The arm that will be operated on is cleaned and draped in a hygienic manner. The surgeon will then mark on your skin where the incisions (cuts) will be made. The main goal of the surgery is to keep the length of your forearm as much as possible and to ensure your elbow joint is preserved.
This is what the surgeon will do during the operation:
1. They will make flaps of skin, both on the front and back of your arm, to cover the operated area adequately. Sometimes, if there is not enough skin, they may do skin grafts (transplantation of skin from one area of your body to another) or use flaps of skin from other parts of your body. If the flaps of skin are too thin, they may not hold up well, especially if the blood supply to the area is poor.
2. The surgeon will locate and then tie off the two main arteries in your forearm (the radial and ulnar arteries) to stop blood flow.
3. Then, they will cut through the bellies of all 20 forearm muscles.
4. The surgeon will also cut through the three major nerves in your forearm (radial, median, and ulnar nerves). Nerves, when cut, try to heal and regrow, which could lead to a painful mass of nerve tissue, a neuroma. To avoid this, the surgeon will identify all cut nerve endings and resect (cut) them in such a way that they are as far as possible from any external stimuli that would cause pain.
The surgeon will then cut through your ulna and radius (the bones in your forearm) while trying to retain at least 5 cm of your ulna. This is important to help in bending your elbow effectively. After cutting, the sharp ends of the bone will be contoured (smoothed), so they don’t interfere with fitting of a prosthesis (artificial limb). Finally, they will close the deep fascia (a layer of tough tissue), subcutaneous tissue (the layer just under the skin), and the skin itself.
After the surgery, it is crucial to start using a prosthesis and moving your forearm, elbow, and shoulder as soon as possible. To help with this, you might be given compression stockings, stump protectors, and surgical drains to prevent unwanted collections of fluid.
Possible Complications of Forearm Amputation
People who go through forearm amputations generally experience fewer complications than those who have lower-limb amputations. However, there are common issues that may occur, including swelling (edema), local infection, wounds not healing properly, and grafts (transplanted tissues) not working as they should. These cases aren’t common, but it’s important to notice them early on.
One of the main issues that people who lose an upper limb face is also called phantom limb pain. This happens when someone feels pain in the part of the arm that has been removed. It’s estimated that 40% to 80% of people who lose an upper limb experience this. Since it’s quite a complex condition, several kinds of treatment are often needed to manage it.
After surgery, if the person continues to bleed, they can form what’s known as hematomas – clumps of blood that can swell up under the skin. This can be reduced by carefully controlling the bleeding during surgery and using a medical device called a drain.
In all cases, the natural response of the body after having a nerve cut is to form a neuroma, which is an often painful growth or swelling on a nerve.
Joint contractures, or stiffness that makes it difficult to move the joint, are typically prevented by getting the patient to move around immediately after surgery. If they do occur, a more intensive course of physical therapy might be necessary.
Revisions, or follow-up surgeries, can be common for people who lost their limb due to trauma. One study found that about 42% of soldiers who lost an upper limb needed another surgery, and those who had an forearm amputation were almost five times more likely to suffer from phantom limb pain.
Lastly, it’s important to consider the psychological impact of an amputation. Research found that people who lose an upper limb are more likely to have post-traumatic stress disorder (PTSD) and disabilities compared to those who lose a lower limb. The psychological strain has a significant impact especially in an active population, causing high rates of disability.
What Else Should I Know About Forearm Amputation?
Losing an arm, particularly around the forearm area, is an incredibly significant event that typically happens as a result of sudden, surprising injuries. Other health problems often come hand in hand with this kind of trauma and they should be addressed first. Of course, the most important thing is to keep the person alive, even if it means losing a limb, but we also aim to protect as much of the arm’s function as possible. Deciding to amputate involves taking into consideration a variety of different factors. No matter how this situation pans out, the result will have a huge impact on the physical health, mental well-being, and finances of the person involved.
