Overview of Flaps: Muscle and Musculocutaneous
A flap is a piece of tissue that has its own supply of blood. It is different from a graft, which is a tissue piece that is removed from its original blood supply and moved to a new area where it blends in with the surrounding tissue. The practice of using flaps has a long history, dating back to 600 BC when an ancient Indian doctor named Sushruta used it for nose repairs after amputations.
Unlike grafts, which depend on the blood supply of the wound it’s attached to in order for it to survive, flaps include more tissue and have their own source of blood. Research on anatomy, technological advances, and learning from injuries during wars led to further development of the flap reconstruction technique. It is now used to treat a wide variety of defects resulting from trauma or cancer.
In the 1900s, European surgeons began to experiment with muscle and skin flaps, particularly for rebuilding faces of soldiers wounded in World War I. This gave rise to the concept of angiosomes and prompted studies into the blood supply of superficial muscle tissue. These early flaps were largely based on random blood supply and performed in stages, but they were still very successful.
As knowledge of anatomy and physiology grew, we began to understand the blood supply to various parts of the body better. This understanding made it easier to move tissue from healthy parts of the body to wounded areas. Among the early successful procedures were the use of abdominal muscle flaps to strengthen hernia repairs and the first muscle flaps in breast reconstruction after mastectomy.
Over time, with advancements in surgery, microsurgery and free-tissue transfer, muscle flaps have become a crucial technique in various types of reconstructive surgeries. Even though other types of flaps have gained popularity, muscle flaps, which have a steady blood supply, remain a good option for many types of reconstructions. Moreover, muscle flaps can effectively fill in vacant areas and help to reduce bacteria concentration in wounds. They are an invaluable tool in modern reconstruction surgery.
Anatomy and Physiology of Flaps: Muscle and Musculocutaneous
Muscle and skin-muscle flaps, also known as ‘myocutaneous flaps’, are classified based on how they receive their blood supply. Mathes and Nahai presented a system to label these into five types. Type I includes muscles like the ‘tensor fascia lata’ and has one main blood vessel. Type II muscles (e.g. ‘gracilis’) have one main blood vessel and several smaller ones. Type III muscles, like ‘rectus abdominis’ and ‘gluteus maximus’, have two main blood vessels; they only need one to survive. Type IV muscles, including the ‘sartorius’ and ‘tibialis anterior’, don’t have a main blood channel but instead receive blood from multiple smaller channels. Type V muscles, like the ‘pectoralis major’ or ‘latissimus dorsi’ muscle, have one main blood vessel and some extra smaller ones; they can get nutrients from these smaller ones if the main one is blocked.
Muscle flaps can be used where they are, keeping connections to their blood supply, or they can be moved to a different place for rebuilding, which needs reconnecting of their blood supply in the new location. Myocutaneous flaps carry skin, soft tissue beneath the skin, a related tissue called fascia, and the muscle underneath it. Unlike other tissue flaps, myocutaneous flaps are not separated into parts, which makes it easier to move them around.
Muscle flaps serve as a new tissue surface with a functioning blood supply and can fill spaces left by removed or diseased tissues. Myocutaneous flaps, on the other hand, can bring volume to the transplantation spot and remove the need for a skin graft. It’s important to understand where blood vessels go inside these flaps. Knowing this can help doctors plan the size and shape of the cut they need to pull from the skin. Dr. Taylor and Dr. Palmer first brought forward this idea of ‘angiosomes’ in a paper in 1987.
When transferred tissue gets to its new home, it begins to blend in with the surrounding tissues. Given a healthy blood supply in the new location, new blood vessels will grow into the tissue within four to five days, but it takes several weeks to supply the flap independently of its initial blood supply.
Why do People Need Flaps: Muscle and Musculocutaneous
Muscle and skin-and-muscle flaps (called myocutaneous flaps) are helpful for many different kinds of physical damage, including cancer or injury. These flaps are often used in areas like the head and neck, back (for pressure sores), groin area, arms and legs, and breasts. Muscle flaps are particularly useful for wounds that have a high risk of infection or have a large hollow space that needs to be filled in.
When deciding on which flap to use, several factors need to be considered. Medical professionals have to establish the size and tissue components required for reconstructing the wound, the potential function and discomfort of the donor site (the area where the flap comes from), and the future function and look of the wound area.
For example, surgery to help restore facial movement might require a transplant of tissue that’s thin, flexible, and has its own nerve supply, like the gracilis muscle (located in the thigh). But for pressure sores, thicker skin-and-muscle flaps are used because they can withstand pressure better than a muscle flap covered with a skin graft.
When reconstructing limbs, weight-bearing areas usually benefit from a skin-and-muscle flap. This is because constant pressure on a site that has a skin graft can sometimes lead to it deteriorating or breaking down.
When a Person Should Avoid Flaps: Muscle and Musculocutaneous
Sometimes, certain conditions can make it less safe or effective to use muscle or skin flaps in surgery. These are called ‘relative contraindications’, meaning they may influence the surgeon’s decision but won’t necessarily stop the procedure.
Some reasons to be cautious include:
- If the person or their family has a history of blood clots or bleeding problems
- If the area where the surgeon plans to take the muscle or skin flap has received radiation treatment
- If the person has had surgeries that might affect the blood flow to the muscle that will be used
- If removing a certain muscle would cause serious disability
For example, if a surgery is considered for the latissimus dorsi muscle (a large muscle on the back), the surgeon would take into account whether any previous surgery or radiation treatment has affected the related blood vessels. Also, the rectus muscles (muscles in your belly) may not have a good blood supply if the person has had certain types of abdominal surgery or heart surgery. In such cases, the surgeon may have to consider different surgical methods.
Smoking can also be a relative contraindication as it can slow down wound healing. Additionally, using a muscle that could cause lasting damage or instability to a joint also needs to be considered.
It’s important to note that if a person’s blood circulation is unstable and needs drug support to keep it steady, it may not be safe to perform a surgery involving ‘free tissue transfer’. This is when tissue from one part of the body is moved to another beyond the area of the original injury.
Equipment used for Flaps: Muscle and Musculocutaneous
For a specific type of surgery that involves moving muscles or skin (a procedure called free flap surgery), special tools for microsurgery and a magnifying device or a super-powerful microscope are required. In addition, certain drugs – like lidocaine (a numbing medicine) or papaverine (used to increase blood flow) – should be on hand to help address any issues with the blood vessels suddenly narrowing (a condition known as vasospasm).
If the surgery plans to involve connecting small blood vessels (a process known as microvascular anastomoses), whether this involves freely moving tissue, or “supercharging” tissue that’s still attached to its blood supply (also known as pedicled flaps), a special type of saltwater solution mixed with a blood-thinning medicine called heparin and medications that can dissolve blood clots (known as IV thrombolytics) should be available. A hand-held device used for detecting blood flow (called a doppler unit) is also needed in the operating room.
Depending on what’s available, different tools for monitoring the tissue during and after surgery, or a device that can be implanted to help measure blood flow can come in handy. The surgery that simply involves moving a muscle or muscles while they’re still connected to the body, without using any special equipment, can be performed using the standard set of tools for a plastic surgery procedure.
Who is needed to perform Flaps: Muscle and Musculocutaneous?
Flap surgery, a procedure where tissue is moved from one body part to help another, needs a skilled team of doctors who are good with tiny surgeries, especially when they plan to move muscle or skin and muscle tissue. Medical centers that do a lot of these surgeries usually have experienced staff who can avoid any complications during the time around the surgery.
Anesthesia providers have a big role too. They need to be okay with a few aspects of flap surgery. For example, they might need to keep the patient’s muscles relaxed for a long time, use a medicine called heparin that prevents blood clots, and make sure the patient’s blood pressure stays normal without using drugs that constrict blood vessels.
In the time around the surgery, nurses and other staff members are also vital. They need to check the tissue flap regularly and watch out for any changes in important health signs like blood pressure, heart rate, and body temperature.
Preparing for Flaps: Muscle and Musculocutaneous
Before any surgery, doctors will ask about your medical history and give you a physical exam. They will pay special attention to the type of surgical flap (skin, tissue, or muscle moved from one part of your body to another) planned, the muscle or skin-tissue flap they will be using, and any concerns related to where the flap will be placed. While not always needed, sometimes doctors will order a type of body scan called a computed tomography with angiography. This helps them see if the main blood vessels involved in the surgery are okay. If there’s any question about these vessels, this type of scan can provide useful information.
If you have a history of blood clotting problems, a specialist known as a hematologist will assess you. They may even suggest that you take medicines to prevent blood clotting during and after the surgery. If you have an existing wound that may be contaminated, doctors will clean it thoroughly and remove any unhealthy tissue multiple times before the surgery. This is done to reduce the amount of bacteria in the wound before the tissue is transplanted.
Since these types of surgeries can be long and recovery takes time, it’s important that you are as healthy as possible. This includes having good nutrition levels. Your doctors will check this. Also, the nursing and support staff taking care of you must be experienced in taking care of patients who have had these kinds of surgeries.
If skin-tissue flaps are being used to cover pressure sores, therapists will carry out in-depth assessments. They will also use pressure maps and special mattresses and wheelchairs to help avoid putting unnecessary pressure on the treated area. This can greatly improve the chances of a successful surgery.
How is Flaps: Muscle and Musculocutaneous performed
Some background information is necessary to understand the harvesting and transfer of muscle and skin tissues, known as flaps in medical terms, to reconstruct areas of the body. In reconstructive surgery, doctors use pieces of skin known as flaps from one part of the body to repair another. Local muscle and skin flap options depend on the area of the body that needs reconstruction, and sometimes, the doctors use free tissue transfer options where they move tissue from one part of the body to another.
If they’re using tissue from elsewhere in the body—also known as free-tissue transfer—the first step is to identify healthy blood vessels in the area that will be receiving the flap. This is necessary for supplying the transferred tissue or flap with necessary nutrients and oxygen. Once the blood vessels are identified, the doctor can start the procedure for moving the tissue or flap.
For muscle flaps, or muscle tissues moved from one place to another, the doctor makes a cut that allows maximum access to the muscle and associated blood vessels. Unnecessary blood vessels are sealed off by cauterizing or clipping to prevent bleeding, and the muscle is carefully separated from tissue around it. They use special resources to ensure the transferred muscle gets a good supply of blood.
For free muscle transfers, wherein muscle is moved from one part of the body to another, it is crucial that the muscle re-establishes its blood supply as quickly as possible to prevent damage. Once the muscle is carefully set at the recipient site, and bleeding controlled, the surgical wound is closed. In some cases, the doctors may insert drains or special stitches after removing large muscles to prevent accumulation of fluid at the donor site.
For myocutaneous flaps, this involves moving not only muscle but also skin from one part of the body to another. The doctor marks the area of skin to be moved and makes a cut that helps to move the skin flap. In order to avoid damaging the blood supply of the flap, they take extra care, especially when dealing with a large flap, which may need additional care when closing the wound.
Whether or not to reconnect the transferred muscle to nerves—reinnervation—depends on what the doctor is aiming to achieve. In some cases, they might leave the nerve alone in order to prevent unwanted movement of the muscle or make it look more natural in the long term. In particular cases, such as when only a small portion of a muscle is moved, doctors try to keep as much of the original blood supply to the muscle to minimize damage.
Possible Complications of Flaps: Muscle and Musculocutaneous
Some complications that can occur when a piece of muscle or a combined muscle and skin graft (known as a flap) is used in surgery include infections, failure of the graft to survive, buildup of fluid or blood at the place the graft was taken from and the place it was put, fat turning into a hard lump, and the surgical wound reopening. Specific grafts, like the TRAM flap (a type of tummy tuck), can cause a hernia or a saggy belly, while grafts taken from the back muscle (latissimus dorsi) can build up fluid if not drained properly. Also, a gathered blood called hematoma, even if moderately sized, if trapped in a small space, can squeeze and block the blood vessels feeding the graft, leading to its failure.
After surgery, we need to keep an eye on patients who have these flaps to make sure they’re not failing. Muscle flaps that start to turn gray or don’t bleed much when you prick them with a pin are not getting enough blood and should be looked at in the operating room immediately. Flaps made of muscle and skin have the added benefit of the skin serving as a checker for the overall health of the flap. If the skin turns a bluish color, it could be a sign of blood pool or clotting. Unlike flaps made of skin and connective tissue, muscle and combined muscle and skin flaps don’t handle low blood supply very well, and any concern about low blood supply to the flap should be quickly addressed in the operating room. Depending on where the muscle or muscle and skin flap is, we have to make sure the patient is positioned in a way that doesn’t squeeze the blood vessels supplying the flap. For flaps in the limbs, patients should follow a hanging-leg method to avoid the harmful effects of blood pool.
What Else Should I Know About Flaps: Muscle and Musculocutaneous?
A muscle flap or myocutaneous flap is a type of tissue transfer used in surgery. The term ‘flap’ in this context refers to a piece of tissue that is still attached to the body by a major blood supply (known as ‘pedicled’) or is detached and then reattached elsewhere (‘free tissue transfer’). These flaps are beneficial for various procedures, like rebuilding body parts after cancer treatment or injuries. ‘Work-horse’ flaps simply means that these types of flaps are commonly used and reliable in these procedures.
