Overview of Nasoseptal Flap
The nasoseptal flap, a technique widely used in skull base reconstruction, has revolutionized this field of surgery. Before the introduction of this procedure in 2006, surgeons used other nearby tissues like pericranial or temporoparietal fascia flaps which potentially caused more harm to the patient. Sometimes, surgeons can fix the front part of the skull base using non-vascularized natural or synthetic tissue grafts.
However, when the skull base has large defects and potential cerebrospinal fluid leaks – that’s the clear body fluid surrounding our brain and spinal cord – we need to use a technique that restores the vascularization, or blood supply, to the tissue. This is important to prevent post-surgery fluid leak and complications.
The nasoseptal flap procedure uses the mucosa tissue from inside the nose based on a vascular pedicle, meaning a stalk of tissue containing the blood vessels needed. This method reduces the risk for the patient and increases the success rate for these complex surgical procedures involving the front part of the skull base.
Such a procedure, also known as the Hadad-Bassagasteguy flap, was developed at the University of Rosario, Argentina, and the University of Pittsburgh. Since its first description in 2006, many have theorized about enhancements, proposed expansions, and outlined more situations where this procedure could be used.
Anatomy and Physiology of Nasoseptal Flap
The nasal septum is the part of your nose that divides it down the middle and supports it. It consists of four main parts: the maxillary crest, the vomer, a section of the ethmoid bone, and quadrangular cartilage. It extends from the bottom of the nose to the back, covering the entire nasal cavity. Both the bony and cartilaginous parts are covered in a protective layer, and the whole septum is covered with a moist layer of skin called mucosa. This mucosa is rich in blood vessels and looks like columns of cells under a microscope.
The blood supply to the septum comes mainly from three arteries, with some additional supply from two more arteries and a branch of the facial artery.
The nasoseptal flap is a small piece of tissue that’s attached at one end and based on an artery in the septum. This artery comes from another artery in the jaw. The flap can be anywhere from 5.2 to 8.6 cm long and 3 to 4.5 cm wide in adults. It’s confined within the borders of the nasal septum, with some arrangements to protect the artery.
Sometimes, doctors might modify this flap to add more tissue. This is helpful when large defects in the skull base need to be repaired, often by also including the floor of the nose and possibly the side wall.
When the mucosa and perichondrium (the protective covering) are raised from the bony and cartilaginous septum, the exposed areas will re-mucosalize, or regain their mucous membrane, provided the other side is intact. The topmost part of the septum not only helps to line and moisten the nasal cavity but also aids in the sense of smell. A small 1 to 2 cm part of this top section contains the cells involved in our sense of smell. At the bottom part of the septum, many people have a small dent called the vomeronasal organ or Jacobson’s organ. This is believed to be a leftover organ whose usefulness is still debated among scientists.
Why do People Need Nasoseptal Flap
In the past, doctors would often use a technique called the ‘nasoseptal flap’ in order to repair large areas of damage to the front and underside of the skull following a specific type of brain surgery. The ‘nasoseptal flap’ involves utilizing a patient’s own nasal tissue to cover the affected area, thereby promoting healing.
However, in the last twenty years, the situations in which doctors might use a nasoseptal flap have increased, and researchers are currently studying how beneficial these new methods are.
It’s been found that a nasoseptal flap can be used to cover a remarkably broad range of areas within the skull, extending from the ‘cribriform plate’ – a thin, delicate bone near the nose – all the way back to the ‘clivus’, a part of the skull located at the back of the head.
In addition, new studies are investigating the use of nasoseptal flap in other areas of the body such as the nasal cavity, skull, mouth, and throat. This is being done after surgeries done with the help of specialized robots. In these cases, the nasoseptal flap is routed through the patient’s palate to repair tissue damage in areas, such as the jaw, the ‘Internal Carotid Artery’ or ICA, which supplies blood to the brain, or as far back as the ‘vallecula’, a part of the throat.
When a Person Should Avoid Nasoseptal Flap
For some patients, using a nasoseptal flap—which is a piece of tissue from the middle of the nose used for repairing an internal part of the nose—may not be possible or recommended. This can be the case if tumors in the nose and sinus have reached the septal mucosa (the mucous membrane lining the septum) or sphenopalatine artery and branches, making it not usable anymore. Previous surgeries affecting the back of the nasal septum, the sphenoid sinus (one of the sinus cavities located in the center of the skull), or the SPA (an artery in the nose) can also make the use of a nasoseptal flap not possible. Interestingly, past simple septoplasty, meaning a surgical procedure to straighten the nasal septum, does not prevent the use of a nasoseptal flap.
If a nasoseptal flap can’t be used on the same side, there are many other options. Often, a nasoseptal flap from the other side can be used instead.
Other alternatives to using a nasoseptal flap include inferior and middle turbinate flaps. These are flaps made from other tissues within the nose. In certain cases where the defects are quite large, a temporoparietal fascia flap (from the side of the head), pericranial flap (from the outer covering of the skull), palatal flap (from the roof of the mouth), or free tissue flap (from other areas of the body) may be required.
Equipment used for Nasoseptal Flap
The medical equipment and specific steps taken during a surgery can vary depending on the surgeon’s preference, even though there are typically accepted procedures and tools used. For surgeries involving the sinuses or skull, the room would be prepared as per routine for these types of operations. The patient will generally be put under Total Intravenous Anesthesia (TIVA), a method where the anesthesia is given through an IV rather than inhaled, as long as it’s safe considering their overall health and the anesthesiologist agrees. This method can help make the operation area clearer to see. The patient may also be positioned in a way that their feet are higher than their head, known as the reverse Trendelenburg position, to assist with stopping any bleeding and to provide a better view for the surgeon.
Although there should be several types of endoscopes at hand, the surgeon usually uses either one with a 0 or 30-degree lens. An endoscope is an instrument that helps the surgeon see inside the body during the procedure. The surgeon will also typically use a tool for cutting and stopping bleeding at the same time that has a needle tip bent at a 45-degree angle. Other instruments that might be used include a Cottle elevator, a tool used to lift tissues, micro-scissors, a probe with a rounded tip, a curette for scraping tissue, a curved suction device with a soft tip, as well as forceps and scissors that can cut both straight and at an angle. These tools are usually found on a tray that is prepared for Functional Endoscopic Sinus Surgery (FESS), the common type of sinus surgery. These instruments are chosen specially to avoid damaging tissues while the surgeon lifts the flap to get access to the surgical area.
The surgeon might use a variety of synthetic, body-derived, or even donor materials to provide support underneath the flap that they raise up. These materials include artificial dura mater (the thick membrane that covers the brain), the person’s own fat and fascia (a layer of connective tissue), and packing that can be absorbed by a body. After the operation, they may use a type of dressing called xeroform gauze, or even a medical balloon called a Foley balloon to prop up the graft (the tissue that was moved) and any other materials used. Like many aspects of the surgery, the choice of instruments and materials often depends on what the surgeon prefers to use.
Who is needed to perform Nasoseptal Flap?
To successfully carry out a nasoseptal flap procedure, a highly skilled and well-equipped surgical team is vital. This team includes a nurse who helps in the operating room, a scrub technician who assists the surgeon, an anesthesia provider who ensures you stay pain-free during the operation, and a skilled sinus and skull base surgeon.
The nasoseptal flap operation is often performed by a medical specialist called an otolaryngologist. These are doctors who have received specialised training in diseases of the nose, ears, and throat, including the challenging horse shoe-shaped region at the back of the nose and the base of the skull. Notably, many neurosurgeons are also highly skilled in this type of operation. They can lead the procedure, assist, or consult depending on the specific case, the procedure’s location, and the hospital’s rules.
If the approach to this surgery involves different types of materials, experts who know how these materials work and their limitations should be on hand to ensure they are used safely and effectively. These experts can support the team in-person or virtually. Please remember, this coordination helps your surgery be safe and successful.
Preparing for Nasoseptal Flap
Before carrying out a surgical procedure known as a nasoseptal flap, doctors will first gather a detailed history of the patient’s health. This includes an in-depth discussion about the need for surgery and any illness the patient might be currently experiencing. It’s also important to know about any previous surgeries the patient has had, especially those related to the nose.
Doctors will then perform a thorough physical examination of the patient’s head and neck followed by an in-depth examination of the inside of the patient’s nose using an endoscope – a flexible tube with a camera at the end. This endoscope test gives doctors a close look at the inside of the nose, allowing them to check for any structural abnormalities, like a deviated septum or signs of past surgeries.
Imaging tests, like CT scans and MRI scans, are also crucial for preparing for this type of surgery. These are detailed pictures of the inside of the body that help surgeons plan the procedure and navigate during the operation. While CT scans are commonly used for sinus surgeries, MRI scans are usually used for brain and skull base conditions. For best results, doctors often use both types of imaging before a nasoseptal flap procedure.
Doctors also use these tests, along with the patient’s full health history and the results of the nasal endoscopy, to spot any potential issues that might make the nasoseptal flap procedure more difficult or potentially risky. Patients are also advised to stop using all nasal medications and to avoid new nose piercings as these can affect the surgical process.
Since this kind of surgery involves an area that is not completely clean, there’s no need to clean the outside or inside of the nose before the procedure. However, the hair-like structures (vibrissae) in the nose should be trimmed down to prevent the collection of blood or other fluids, which could make the scope dirty and cause complications during the surgery. Lastly, appropriate surgical draping or covering is required for the patient, suitable for the specific surgical steps of the procedure.
How is Nasoseptal Flap performed
The procedure starts with treating the congestion in the nose using a medication like 0.05% oxymetazoline, 4% cocaine, or 1% phenylephrine, which are medical sprays used to clear the airflow. Local anaesthesia, which numbs the area that is undergoing surgery, is applied to the nasal septum (the thin wall in your nose that separates your right and left nostrils) on the side where surgery will be performed.
The surgery begins by moving or cutting parts of the nasal passage for easier access. The middle part of the nose (known as the turbinate) is usually moved or cut in such a way that makes it easier for the doctor to access. Then, the surgeon will measure and plan the surgical area in detail to avoid any complications.
Making sure that the part of the nose responsible for smell (olfactory epithelium) is not harmed while performing the surgery is an important step at this stage. There should be a balanced approach where the urgency of obtaining more area for operation should not risk the sense of smell.
The surgeon will make two parallel cuts: one over the maxillary crest and another 1 to 2 cm below the superior aspect of the nasal septum to avoid the olfactory epithelium. The surgeon will then connect these cuts with a perpendicular cut. They will do this very carefully, especially the posterior cuts, as they are near the blood supply, known as the vascular pedicle.
Elevating the nasal flap (lifting the layer of tissue) is the next step. This is typically done with a special tool, such as a Cottle elevator, Freer elevator, or a suction-Freer elevator. Care is taken at this stage to avoid injuring the vascular pedicle overlying the sphenoid rostrum, a ridge at the base of the skull. It’s like carefully lifting a layer of carpet without causing it any damage.
Once the nasal flap is raised, it is kept aside securely, typically in the nasopharynx (a part of your throat behind your nose), or in the maxillary sinus (a space within the bones of your cheeks), based on the needs of the procedure.
The reconstruction of the defect is then dependent on the severity of the defect and the surgeon’s preference. Various types of materials such as autologous grafts (body’s own tissue), synthetic materials, and flaps (pieces of tissue with their own blood supply) are considered. Once the nasoseptal flap (the ‘carpet’ which was kept aside) is placed back into the defect, absorbable packing (a substance that will get naturally absorbed by the body over time) is placed.
The surgeon then often uses a xeroform gauze or a Foley balloon (both of these are supportive materials) to support the packing but care is taken not to overinflate the balloon as it can displace the flap within the cranial vault (a space inside the skull) or out of the defect.
Lastly, a flap from the other side of the nasal septum can be used to cover the donor site from where the flap was originally harvested, although this may prevent the possibility of using the flap on this side of the nose in future procedures.
Possible Complications of Nasoseptal Flap
The nasoseptal flap is a method used in skull base surgery that is popular among surgeons due to its wide range of uses, high success rates, and low chances of complications. This technique has also proven to be safe in children, with no signs of it affecting the growth and development of their head and face.
Complications from this surgery are very rare. In a study of 44 patients, only a few minor complications were reported, such as a CSF leak (where fluid from around the brain starts to leak), a nosebleed that needed treatment, and some cases of asymptomatic synechiae (abnormal tissue growth). These issues were all resolved, the flap was preserved, and the septum (the wall dividing the nostrils) healed without any perforation (holes).
A research study in Australia aimed to see how the quality of life changed after people had the nasoseptal flap surgery. They found that, compared to other surgical methods, patients initially reported a decrease in their quality of life score and experienced increased ear pain and a reduced sense of smell. However, six weeks after the surgery, these negative effects had disappeared and the patients’ quality of life was no different from those who had undergone different methods of surgery. Other studies have found that a minor decrease in smell might last up to six months after the surgery.
What Else Should I Know About Nasoseptal Flap?
In 2006, a significant development in anterior skull base surgery happened with the description of the nasoseptal flap by Hadad and Bassagasteguy. This flap, a piece of tissue in the nose, is now a fundamental tool in surgeries involving the front part of the skull base. It’s particularly useful when combined with other local flaps, which are other pieces of tissue used in surgery. The use of the nasoseptal flap has greatly helped to reduce complications for patients who otherwise would need a more complex form of reconstructive surgery.
One great benefit of the nasoseptal flap is that it drastically reduces the occurrence of cerebrospinal fluid (CSF) leakage. In early days of a surgical approach called the endoscopic endonasal approach (a way of operating through the nose), the rate of CSF leakage was as high as 24%. However, recent studies have shown that, with the use of the nasoseptal flap, this complication rate drops to as low as 3%.
The applications of the nasoseptal flap are gradually increasing as more and more surgeons across various specialities start to use it. It hasn’t yet been explored fully in reconstructing the palate (the roof of the mouth) and pharynx (the passage leading from the mouth to the esophagus), but it has the potential to be combined with other flaps from these areas.