Overview of Paramedian Forehead Flaps
Interpolated flaps, along with rotation and transposition flaps, are techniques often used in facial reconstruction surgeries. These types of flaps are used to repair damaged or lost tissue on the face. The term ‘flap’ refers to a piece of tissue that is still attached to the body by a major artery or vein. This ‘flap’ is then moved to a new location on the body to cover a defect.
An ‘interpolated flap’ is a little different from other types of flaps. Instead of being located right next to the area to be repaired, the flap’s ‘base’ (where it’s attached to the body) is located somewhere else and has to pass over some tissue to reach the place where it’s needed. Because of this, some doctors consider them to be more of a ‘regional flap’ (flaps that come from the same region of the body as the defect) rather than a ‘local flap’ (flaps that come from right next to the defect).
There are many types of interpolated flaps that can be used in facial reconstruction, like nasolabial flaps (which use skin from beside the nose) or forehead flaps. Flaps from the forehead have been used a lot since they were popularized by a surgeon named Gillies during the First World War. The skin in the middle of the forehead is very similar in quality and thickness to the skin on the nose, making these flaps ideal for nose reconstruction. Plus, the blood supply to these flaps is very reliable, which is essential for successful surgery.
Using a forehead flap for nose reconstruction usually involves at least two separate surgeries, generally about three weeks apart. Some surgeons may prefer to use a third surgery for additional adjustments. Although this procedure leaves a scar on the forehead, it’s usually not very noticeable. Most patients and surgeons agree that the results look and function well.
Anatomy and Physiology of Paramedian Forehead Flaps
When a doctor plans a type of reconstructive surgery called a paramedian forehead flap, they think about the forehead in three distinct areas, each with different blood vessels. This means, they can move a section of forehead skin (flap) that can cover the entire nose. Different blood supplying arteries and their linked veins exclusively feed this flap, providing a specific blood supply to this moved skin. Understanding this blood supply helps doctors ensure that the moved skin gets enough blood and stay healthy.
Just beyond the top layer of skin (dermis) is a thin layer of fat. Underneath this fat is a muscle called the frontalis muscle, which helps lift your eyebrows and is placed near the hairline. Below this muscle lies a looser layer that separates it from the skull bone. Around the rim of the upper eye socket, the muscle that helps you blink (orbicularis oculi) is stuck to the deeper side of the dermis with no significant fat between them. A muscle that causes wrinkles when it moves (the corrugator supercilii muscle) is below the orbicularis oculi. The muscle just on top of the corrugators, the procerus muscle, is responsible for horizontal lines on the forehead when it contracts.
The forehead receives its blood supply from several arteries. These include the supratrochlear, supraorbital, superficial temporal, and dorsal nasal arteries. The supratrochlear artery comes from the artery that supplies the eye (ophthalmic artery) and runs between the muscle that helps you blink (orbicularis oculi) and the muscle under it (corrugator supercilii).
When the supratrochlear artery reaches the forehead, a branch diverges and could potentially supply a flap of skin that is moved during surgery. This artery then travels between the muscle enabling you to blink (orbicularis oculi) and the muscle that horizontally wrinkles your forehead (frontalis muscles). This artery goes deep inside for about 1 inch before moving sideways and coming closer to the skin surface. Therefore, during surgery, the doctor designs the flap so that it includes the blood supply from the supratrochlear artery. This artery helps supply blood to the forehead, and tilts your eyebrows up.
The supratrochlear vein that runs alongside the artery plays a crucial role in carrying the blood away from the forehead to the rest of the body. Understanding all these intricate details about the blood vessels in the forehead helps the doctors in successfully performing a forehead flap reconstruction.
Why do People Need Paramedian Forehead Flaps
A paramedian forehead flap is a type of surgical treatment used mainly to rebuild large defects of the nose; however, it can also be used in reshaping the areas around the eyes and certain parts of the skull base. This kind of treatment would typically be used for nose-related issues larger than 1.5 to 2 cm. If the issue is smaller, we often choose simpler methods like a skin transplant or using a bilobed flap – a two-pronged piece of skin graft.
However, when extensive losses of particular tissues prevent the creation of a well-vascularized bed needed for healing a graft, skin grafting might not work. That’s where paramedian forehead flaps come to the rescue. They provide more than enough skin coverage to replace various parts of the nose, especially useful when more than half of the nose part is lost and needs complete replacement to achieve the best possible look.
The nose parts that are commonly rebuilt this way include the tip of the nose, columella (a tiny column of skin separating the nostrils), tissue triangles, alae (wings of the nose), and the back of the nose. However, in occasional individual cases, we might opt for different procedures, like Rieger flaps for the back of the nose or nasolabial flaps for nose rebuilding.
When it comes to significant defects, such as full nasal reconstructions – medically termed rhinectomies – paramedian forehead flaps can serve as a practical alternative to the transfer of free tissue from other parts of the body, such as radial forearm flaps (tissues from the forearm). Some surgeons also use this procedure in complex, multi-step procedures where paramedian forehead flaps are then folded or wrapped around structural components like bone, cartilage, or titanium plates to establish full nasal reconstruction.
When a Person Should Avoid Paramedian Forehead Flaps
For someone who needs their nose reshaped or repaired, the paramedian forehead flap is a useful technique. However, this method may not work for everyone due to various reasons. One reason is if they’re a smoker. Smoking can make it harder for the body to heal because it affects blood vessels. Another reason is if they’re not comfortable with having a scar on their forehead. Also, people with low hairlines might end up with too much hair growing on the flap, which could be an issue.
There also needs to be caution when someone has a wound, an infection, a lesion, or disrupted supratrochlear blood supply (blood flow to the forehead) because of earlier surgeries – these also might mean alternative methods need to be considered. Finally, if the patient might not be able to take care of themselves between surgical stages, especially if there’s a risk they might disturb the flap’s pedicle (the bit that keeps the flap alive and connected), another type of nasal reshaping or repair might be a better option.
Equipment used for Paramedian Forehead Flaps
When a medical procedure needs to be performed to relocate a section of skin or tissue (called a flap), a certain set of tools is required. These tools would be used to lift the flap, move it, attach it to the new location, and then separate it from its original source. Here’s a simple list of what’s generally needed:
- A surgical marker to mark where the surgery should take place.
- Some local anesthetic, like 1% lidocaine with 1:100,000 epinephrine, which is used to numb the area. This is injected via a tiny needle (27- or 30-gauge) attached to a special medical syringe.
- A material like a foil suture packet. This is used as a guide or template for the flap of skin or tissue.
- Surgical sponges used for absorbing body fluids during surgery.
- A Doppler ultrasound probe, a device for monitoring blood flow in the relocated flap.
- A measuring tape or calipers to ensure accurate measurements.
- A #15 blade scalpel and a #3 Bard-Parker handle, the usual tools for cutting skin.
- Electrocautery device, used to control bleeding by heating tissues.
- Dissecting scissors meant for surgical operations, like Kaye blepharoplasty, strabismus, or small Metzenbaum.
- Forceps (like Adson-Brown or similar) which are like tweezers for holding onto tissues.
- A needle driver (like Halsey or similar), a tool that holds sutures while stitching wounds.
- Suture scissors (Mayo or similar) used to cut sutures, the thread-like material used to hold tissues together after surgery.
- A periosteal elevator (like Freer, Cottle, or Joseph), used to separate tissues for better access.
- Skin hooks to pull back the skin, giving the surgeons a better view.
- Lastly, sutures (Stitches) are needed to close up the place where the flap was taken from and to secure it in its new location.
Who is needed to perform Paramedian Forehead Flaps?
When you have a surgery called ‘paramedian forehead flap transfer’, you usually have a small team with you. This team includes a surgeon who performs the operation, a nurse who helps take care of you, and an assistant or surgical technologist who helps during the surgery. If the operation is large or complicated, there might be an anesthesia provider. This person may give you medicine to make you sleepy or completely unaware of what’s happening, depending on what is needed.
Additionally, there may be some extra nurses or support staff who prepare you before your surgery and look after you once it’s done. When you have a team of different professionals working together on your surgery, it makes sure you are safe and promotes the best possible results from the operation.
Preparing for Paramedian Forehead Flaps
Helping patients understand what to expect before, during, and after a procedure is very important for achieving the best possible outcome. With certain procedures, there can be noticeable changes in appearance over different stages of treatment. For instance, a flap pedicle, i.e., a piece of tissue connected to the body by a bridge of skin and muscle, may stand out between the forehead and nose during particular stages. This temporary change can be inconvenient or lead to social discomfort. Patients should also be aware of other possible aftereffects like bruising, swelling, bleeding, infections, and how their scar might look eventually.
There will be a strong emphasis on ensuring patients fully understand these changes, especially the visible flap pedicle, especially if there’s a delay before dividing it (separating and moving it to its final position). It’s also important to instruct on how to care for the wound on both the donor site (where the flap was taken from) and the pedicle. Other important patient education topics might include quitting smoking, when to attend follow-up appointments, and what to expect in terms of results and overall surgical outcome.
Before the surgery, the doctors will take precise measurements of the area that needs repair and think carefully about the size of the flap needed to fix it. For procedures that involve the hairline or forehead, they will also look at the height of the front hairline and how much skin can be comfortably stretched on the forehead. If the patient is a smoker, the doctors will use a device that measures blood flow to make sure the main artery in the forehead is not blocked. Just before the surgery, the patient will receive a local anesthetic to numb the surgical area, and their face up to the hairline will be cleaned with an antiseptic solution, usually a product called povidone-iodine, to prevent infection.
How is Paramedian Forehead Flaps performed
Lidocaine, a local anesthetic used for numbing, is injected across the entire forehead and also on the bridge of the nose and the base of the flap (a piece of tissue moved from one part of the body to another part to cover a wound or defective area). After this is done, any unwanted tissue is carefully removed from around the margins of the nasal issue – this is done with a scalpel (a sharp instrument) before the flap procedure begins.
The forehead flap procedure, which is the method used here, is designed carefully so that it includes certain blood vessels (supratrochlear vessels) to keep the tissue healthy and viable, using ultrasonography for support when necessary. The skin at the top part of the forehead is then shaped using a template, to match the area where it will be placed. In certain situations, like for patients with a low hairline, the flap might be designed with a curve to avoid using hair-bearing skin. And, if the flap does extend into the hair-bearing scalp, then careful dissection is done to remove hair bulbs.
If the issue with the nose involves bone, cartilage, or the mucous membrane, along with the skin, there are other advanced techniques for repair. Some involve combining different kinds of tissue for comprehensive repair. Options to replace the mucous membrane lining include inferior turbinate or septal mucosal pivot flaps. An alternative is to place a layer of skin graft on the flap, which can later serve as the mucous component of the repair. This pre-laminated flap is then replaced into the forehead and transferred to the defect three weeks later. This delay provides time for the skin graft to adhere more securely to the flap and for better blood supply to develop.
During the last stage of the procedure, the flap is finally divided, and any unused parts are removed, except for a small triangle of skin used for restoring the part of the eyebrow from where the flap was harvested. This process requires careful repositioning of the base of the flap into the eyebrow for optimal aesthetics.
Possible Complications of Paramedian Forehead Flaps
In a 2019 study by Chen and his team, they looked at 2175 patients who had a type of surgery called paramedian forehead flap transfer. It was found that infection was the most common problem after the operation, affecting around 3 out of every 100 patients. The second most common issue was bleeding after surgery, which happened to about 1.5 out of every 100 patients.
This bleeding usually happens in the first half day after surgery along the edge of the pedicle, or the area where doctors transferred skin to. This can be prevented by sealing off blood vessels during the operation and by advising patients to avoid heavy physical activities. Covering the surgical area with a skin graft or petroleum jelly dressing can also help to control bleeding. If bleeding leads to a collection of blood, or hematoma, it should be removed to prevent infection and improve blood flow.
In rare instances, less than 1 in every 100, the transferred skin flap may not get enough blood supply, leading to tissue death or necrosis. This often happens because of inadequate venous drainage, which could be due to twisting or tension in the skin flap, or to damages to the veins. Symptoms of this issue include firmness, swelling, and dark discoloration, along with dark blood when pricked. This can be treated by frequently pricking the skin with a needle or using medical leeches to remove the stagnant blood. An adjustment to the skin flap might be required in the operating room. If leeches are used, a specific type of antibiotic should be given to prevent a soft tissue infection.
On the other hand, if there’s not enough arterial blood getting to the skin flap, it might look pale, feel cool to touch, and won’t bleed much when pricked. A medication called nitroglycerin paste can help, unless the patient has a heart condition. If an injury to an artery happens during surgery, the flap might need to be removed and replaced with skin from another area.
Patients who smoke, have high blood pressure, underactive thyroid problems, or who have ear cartilage grafting might need to be monitored overnight after surgery. Those who have bleeding after surgery, nerve disorders, or alcohol use problems might have to go to the emergency room or be admitted to the hospital again within two days after surgery.
In the long run, some patients might have scarring on the forehead or distortion of the shape of their nose or eyebrows. However, these problems can usually be fixed with touch-up surgeries or skin resurfacing treatments. If the patient has hair growing on the flap, laser hair removal or electrolysis might be necessary. In some cases, the healing skin underneath the flap might contract, or the skin flap might be too big for the area it covers, resulting in a raised, round deformity. This can be treated with injections of triamcinolone, a type of corticosteroid, but another touch-up surgery might be necessary. Another deformity that might happen is a “trap door” deformity where the flap is raised above the surrounding skin. This can be managed with steroid injections, skin resurfacing, or making a series of small, alternating z-shaped incisions to redistribute the skin.
What Else Should I Know About Paramedian Forehead Flaps?
The paramedian forehead flap is a type of skin graft often used in multiple stages to repair large defects, most frequently on the nose. This flap is a popular option for facial reconstruction due to its reliability. Besides the nose, this graft can also be used in areas around the eye or the front base area of the skull.
