Overview of Basic Flap Design
Reconstructive surgery often involves the creation and relocation of ‘flaps,’ which are pieces of tissue used to close up wounds that can’t be stitched up directly. These flaps can vary widely, as they need to deal with a whole range of different tissue injuries. This could be anything from minor skin damage to extensive injuries involving multiple types of tissue. Because of the diverse nature of these injuries and their various causes, the skills needed for this kind of surgery need to be flexible and always evolving to include new techniques.
Flaps are often used to close up wounds when a large amount of tissue has been lost, for example, due to serious injury or cancer surgery. A couple of typical examples might be the use of a flap from the back muscle (the ‘latissimus dorsi’) to cover a wound in the scalp, or the use of a flap from the forearm (the ‘radial forearm’) to reconstruct part of the tongue.
To successfully relocate these flaps, it’s very important to understand the patient’s anatomy and how their tissues work. This includes being adept at surgical techniques that don’t cause further harm to the delicate tissues. The process of creating and moving these flaps is both a science and an art, bringing together medical knowledge and surgical skill. Seeing positive results from these procedures can be incredibly rewarding, while unsuccessful outcomes can be deeply frustrating.
Anatomy and Physiology of Basic Flap Design
Flaps are essentially bits of tissue used in surgery to repair defects in the body. They can be split into different types according to how they’re supplied with blood, the type of tissue involved, and how far the tissue needs to be moved from its original position to the place of the defect. Each classification has its own considerations regarding body structure and function.
When it comes to blood supply, there are two main types of flaps – ‘random’ and ‘axial’. Axial flaps get their blood from a specific artery that runs lengthwise within the flap, with veins also running in the same direction to get rid of used blood. Usually, these kinds of flaps involve tissue from one specific region of the body only, referred to as an ‘angiosome’, with this region being provided blood predominantly by a single artery. However, sometimes a flap can involve tissue from more than one angiosome but still only rely on one known artery for its blood supply.
‘Random flaps’ get their blood supply from smaller blood vessels located just underneath the skin’s surface. This blood supply system is low-pressure and can be affected by extreme twisting or stretching. These flaps have to be carefully designed to ensure the blood supply isn’t cut off. It’s usually recommended that these flaps be kept within a particular size ratio – the length shouldn’t go beyond three times the width.
Flaps can also be categorized according to the type of tissue they’re made up of. The type of tissue used in the flap should match the type of tissue missing from the defect. Small flaps are often skin-based, but they can also be made from mucosal (the stuff lining the insides of your body), bone, muscle, or fascia (the tissue that encloses muscles and organs). The bigger the defect, the more likely it is that a ‘composite’ flap will be used, combining different types of tissue.
The distance between the initial position of the tissue (donor site) and the place of the defect also plays a role in flap classification. ‘Free’ or ‘microvascular’ flaps are harvested from distant sites and transplanted to the defect site, with microsurgery used to reconnect the blood supply. ‘Regional’ flaps come from parts of the body near the defect and aren’t removed entirely from the body or directly border the defect. ‘Local’ flaps come from body parts directly neighboring the defect, and are primarily used for smaller defects. They move from the donor site to the defect site and are usually skin or mucosal tissue-based.
Movement needed to place the flap in the defect also plays a role in their categorization. Some flaps are simply shifted forward into the defect (‘advancement’), others are turned (‘rotation’), some are swapped with adjacent healthy tissue (‘transposition’), and some are moved either over or under the normal tissue to reach the defect (‘interpolation’). The choice between these flap types largely depends on the defect’s location and specifics.
Why do People Need Basic Flap Design
A flap transfer is a type of surgery used when there’s a wound or an area of damaged tissue that can’t be stitched up directly. This procedure might be needed if the wound is too big or in a tricky location. It’s also used when it wouldn’t be ideal to let the wound heal naturally on its own or be healed with a skin graft, which is a piece of healthy skin taken from another part of your body.
When a Person Should Avoid Basic Flap Design
A flap transfer, a type of surgery where a piece of healthy tissue is moved from one part of the body to another to cover a wound, is not always a good choice for everyone. Some people should definitely not have it. For example, if the wound can be safely and effectively closed by other means, such as with sutures or a skin graft (where a thin layer of skin is taken from another part of the body and placed over the wound), a flap transfer isn’t necessary.
But there are also situations where it might not be the best choice, but it’s not totally out of the question. These are called relative contraindications. If there’s an active infection in the wound, or if some cancer remains after a surgery to remove a tumour, flap transfer might need to be delayed. In these cases, it can often be performed once the infection has cleared up or more of the cancer has been removed. Even if some cancer remains, in palliative care (care designed to make the patient comfortable rather than to cure the disease) scenarios, a flap transfer might still be considered. It’s also important to note that if you’re currently a smoker, you have a higher chance of having problems with the blood supply to the flap, which can cause complications.
Equipment used for Basic Flap Design
The equipment needed for a medical procedure will depend heavily on the type of skin tissue that’s being moved or adjusted.
For minor operations where skin from your immediate area is being adjusted (these are known as local flaps), you probably won’t need more than some specialised tools for handling soft tissue and a local anaesthetic to numb the area.
But more complex procedures, like regional and free flaps where skin may be moved from one area of your body to another, could need a whole range of advanced devices. This can include tools for working with soft tissue, saws for bone, a microscope for the surgeon to see tiny details, tools specially designed for working with very small blood vessels, and medications that can affect your blood flow.
Imagine, for a straightforward procedure like closing a wound after Mohs surgery (which removes skin cancer), your doctor might use:
* Purpose specific knives called scalpel (#15 Bard-Parker blade or #6700 Beaver blade)
* Tweezer-like tools called forceps (Adson-Brown or 0.5 mm Castroviejo)
* A tool for holding and maneuvering a needle, known as a needle holder (Halsey or Castroviejo)
* Specialised scissors used for medical procedures (Iris or Kaye blepharoplasty)
* Normal scissors for the sutures (threads used to close wounds)
* An electrocautery device, which uses electricity to cut tissue or stop bleeding
* Threads for closing wounds, known as sutures (5-0/6-0 polypropylene, 4-0/5-0 poliglecaprone)
* Strips of sticky tape for holding the skin together
* A skin marker for plotting out the procedure
* Local anesthetic (1% lidocaine with 1:100,000 epinephrine) to numb the specific area where the surgery will be carried out
* Scrub solution for cleaning the skin to avoid infection (povidone-iodine or isopropanol)
Who is needed to perform Basic Flap Design?
Each medical case needs different types of medical staff members, but at the very least, you’ll always have a doctor and a nurse helping out. In surgeries that are more complicated, you’ll also see an anesthesiologist (a doctor who gives medicine to make you sleep during the surgery), a surgical technician (someone who hands the surgeon the tools they need) and an assistant surgeon. After your operation, you might also need a nurse and physical therapist to help you recover, especially if your surgery was done on an arm or a leg.
Preparing for Basic Flap Design
Before a surgeon performs an operation, they carefully review each patient’s medical history to create a customized plan for treatment. This plan is designed to meet the patient’s unique needs and health risks, with the goal of providing the best possible results and reducing complications.
When preparing for the operation, the surgeon will review several factors, such as:
- Whether the patient smokes
- If the patient has hardening of the arteries, also known as atherosclerosis
- If the patient has peripheral vascular disease, which is a blood circulation disorder
- Any steroids the patient is taking
- Whether the patient has diabetes
- Any previous surgeries that may have been done where the new tissue graft might be taken from (flap harvest sites)
- The size and location of the area to be repaired (defect)
- The patient’s age and skin health
An angiogram, a type of X-ray used to check blood vessels, might be done before the transfer of tissue (flap transfer). This helps the surgeon see the circulation and structure of the area clearly. This is especially important when the area to be repaired is large, as it requires more detailed reconstruction and, thus, longer surgery time.
When doing a flap transfer, the surgeon takes into account technical aspects of the procedure and the patient’s overall health, functionality, and aesthetic desires. By doing so, the surgeon can most often provide satisfactory outcomes.
How is Basic Flap Design performed
Surgeons use a system known as the “reconstructive ladder” to help them decide what type of method to use to close up a wound. This system goes from the least invasive method to the most complex one. Here are the steps in the ladder:
- Healing by second intention: This happens when the wound heals naturally on its own.
- Primary closure: The wound is stitched up directly after the surgery.
- Delayed primary closure: This is when the wound is closed up a few days after the surgery.
- Skin and composite graft transfer (full thickness or split thickness): Skin from another part of the patient’s body is used to cover the wound.
- Local flap transfer (may include tissue expansion): A portion of skin and tissue near the wound is moved to cover it.
- Regional flap transfer: More than a portion of skin and tissue, maybe even an entire muscle or blood vessels, from the area around the wound is moved to cover it.
- Free flap transfer: Skin, tissue, muscle and/or blood vessels from another part of the body are moved to cover the wound.
- Composite tissue allograft (transplant): Tissue from a donor is used to cover the wound.
To explain a bit more about some of these techniques:
Free Flap Technique
In a free flap technique, the surgeon takes tissue from another part of the patient’s body and moves it to the wound area. The tissue is chosen carefully to make sure that it will be enough to cover the wound and that the blood vessels in the tissue are long enough to be connected to the blood vessels near the wound. For 72 hours after the surgery, the wound is checked regularly to make sure that the blood vessels are healing properly and the new tissue is getting blood flow.
Regional Flap Technique
In a regional flap technique, tissue near the wound is moved to cover it. The tissue is never completely separated from the body. This technique is more reliable and quicker than the free flap technique. It does not require microsurgical equipment and is safer for patients with multiple health conditions. As with the free flap technique, the area where the tissue was taken from may also need to be covered with a skin graft.
Local Flap Technique
For a local flap technique, tissue that is next to the wound is moved to cover it. This tissue has a good supply of blood from small blood vessels in the area. The tissue is lifted carefully to make sure it stays healthy. The wound is then stitched up. After the surgery, the area where the tissue was taken from may also need to be covered with a skin graft.
After any of these procedures, the surgeon closely monitors the wound to make sure it is healing well and the tissue is getting enough blood supply.
Possible Complications of Basic Flap Design
Complications from flap transfer, a type of reconstructive surgery, can be grouped into two categories: problems with the site where the tissue came from (donor site) or with the transferred flap itself. These complications can either pop up right away (acute) or occur much later (chronic).
Problems at the donor site can include things like bleeding, infections, scarring, or loss of function which can cause issues like difficulty walking or tightness in the hand. The exact complications can depend on where the tissue comes from: getting tissue from the hip (iliac crest free flap) may lead to a hernia, or a bulge in the abdomen. Taking tissue from the arm (radial forearm free flap) could result in wrist fractures, and if tissue is taken from the lower leg (fibula free flap), it could potentially cause foot drop, which is a difficulty in lifting the front part of the foot.
Complications with the flap itself mostly involve issues with the flap’s blood supply, which can lead to failure of the surgery to fix the problem. The bigger the problem being fixed, the higher the stakes if the flap fails.
When flaps die, it’s usually because of problems with blood flow. In large flaps, blood flow can sometimes be blocked by a blood clot. In local flaps, the blood vessels near the skin surface can be affected. Issues like too much tension or the tissue not being large enough to support the blood flow can also cause parts or all of the flap to die.
Problems with blood flow can sometimes be caused by a build-up of blood in the area, which needs to be drained quickly. If blood flow issues happen in free flaps, changing the tiny blood vessels can sometimes improve blood flow. In local or regional flaps, rearranging the flap to reduce tension can help. If the blood flow from the flap is blocked, leeches can sometimes be used temporarily to help restore it. It’s very important to give the right antibiotic when doing this to prevent infections.
Early flap failure can be caused by infection, not having enough blood pressure, poor nutrition, and not following medical advice. Generally, if there are no signs of problems with the flap’s blood supply in the first week after surgery, the flap is likely to stay healthy. But even then, long-term complications may occur, such as scarring, tightness in the skin, color or texture differences, abnormal hair growth or loss, numbness, and ongoing pain. That’s why it’s crucial to keep monitoring the site and tackle any issues as soon as possible to give the best chance of a successful outcome.
What Else Should I Know About Basic Flap Design?
The method of transferring tissues, or “flaps”, from one part of the body to another has been a part of reconstructive surgery for over 3000 years. For instance, ancient medical texts describe using tissue from the forehead to cover up a nose defect or injury.
The basic idea behind this treatment hasn’t changed much over this long period of time; it’s all about using body tissues that look and behave similar to the tissue that’s missing or damaged. This way, the body can look and function as naturally as possible after reconstruction.
A good flap for transfer should be just the right size and should be harvested with minimal harm to the donor part of the body. It should fit the injured area perfectly, restoring all its functions and appearance. Also, the transferred tissue should survive and thrive in its new location, reducing the chances of having to go through additional surgeries in the future.
It’s important for surgeons who perform these types of operations to be familiar with a wide range of flap transfer options. Each patient’s situation is unique, requiring a specific type and size of tissue to achieve the best healing results.
