What Are the Frontal Sinuses?

The frontal sinus is located in the sinus cavity between the orbital and anterior and ethmoidal sinuses, between the medial and lateral bone plates behind the frontal eyebrow arch.

The frontal sinus is located in the sinus cavity between the orbital and anterior and ethmoidal sinuses, between the medial and lateral bone plates behind the frontal brow arch.

Chinese name

Frontal sinus

Foreign name

frontal sinus

Shape

Triangular pyramid

Location

Deep frontal bone arch

Frontal sinus -anatomical position

Its body surface projection is a triangular range formed by the nasal root point and the 3cm point above it and the middle 1/3 point inside the eyebrow arch, but the individual differences are large. There is a frontal crypt above and above the sieve funnel at birth, after which it gradually expands to form the frontal sinus. The frontal sinus is basically normal by about 25 years of age. The left and right frontal sinuses each have a triangular pyramid shape, sometimes irregular in shape, and left and right asymmetrical. The size is generally 30mm high, 25mm wide, and 20mm deep. There is often a medial septal separation between the two sinuses. The anterior wall of the frontal sinus is thicker, it is the outer frontal plate, the posterior wall and the floor are very thin, the posterior wall is separated by the meninges and the frontal gyrus, and the bottom wall is the front of the superior orbital wall. The frontal sinus is connected to the nasal cavity by the nasal frontal canal and opens in the meniscus hole of the middle nasal passage. If the nasal frontal canal is blocked by rhinitis or tumor, it can easily cause the formation of frontal sinus cysts, which can invade the eye socket for a long time, causing the eyeball to protrude downward. Other tumors and inflammation of the frontal sinus also easily spread to the eye socket.

Frontal sinus- related clinical techniques

1. Nasal endoscopic frontal sinus surgery: The anatomy of the frontal crypt is relatively complicated, the operation skills of the operator are higher, the requirements for surgical instruments and image monitoring equipment are higher, and improper treatment can lead to more serious surgery. Complications, these factors determine that transnasal endoscopic frontal sinus surgery is a hot issue in the field of nasal surgery.

2. The key factor that determines the success of the operation is to ensure the smooth drainage of the frontal sinus. Postoperative frontal sinus stenosis is one of the main causes of surgical failure, accounting for about 25% of all surgical failure cases. The main influencing factors of frontal sinus stenosis are insufficient understanding of the frontal crypt anatomy, which leads to failure to clear the frontal sinus drainage channel. At the same time, blind or excessive surgical operation may also cause adhesion and blockage of the postoperative drainage channel. With the deepening of the research on local anatomy and CT imaging, the complexity of frontal sinus drainage channels in anatomical and imaging has gradually appeared. Frontal ethmoid air cells, including nasal mound air cells, frontal air cells, supraorbital ethmoidal air cells, frontal sinus septum air cells, upper ethmoid air cells, and frontal air bubble cells, can cause narrowing of frontal sinus drainage channels.

3. Surgery classification: From the perspective of anatomical structure, the frontal sinus opening from the outside to the inside is in order: orbital cardboard, anterior sieve, middle turbinate vertical plate, and nasal septum. The range of the lesion is different, and the range of the corresponding operation is also different, which results in the corresponding type of surgery. There are two types of classification systems commonly used for endoscopic frontal sinus surgery: the classification system proposed by Draf in 1991 and the nasofrontal approaches (NFA) surgical classification proposed by May et al. In the United States in 1995. , But there is a corresponding relationship between the two, the former is more commonly used. The higher the classification, the greater the scope of the surgery.

The main steps of the operation include: enlarging the frontal sinus opening in the nasal septum and orbital cardboard on both sides of the nasal cavity (DrafB surgery) to remove the unilateral frontal sinus floor; The upper part of the connected nasal septum is about 2.5cm at the junction of the square cartilage and the vertical plate of bone; Remove the frontal sinus space upwards as appropriate, and use the front end of the middle turbinate as a reference to remove the forehead and back to the olfactory nerve fiber. regular postoperative tamponade, can be placed (3-6 months) if necessary to prevent postoperative stenosis.

Surgery is suitable for the treatment of intractable frontal sinus lesions, such as the frontal sinus anteroposterior or minimal diameter (<5mm), the failure of anterior surgery (Draf type II surgery), and the removal of osteomas or inverted papillary invading frontal sinuses Tumors and other extensive lesions.

Frontal sinus precautions

1) Enlarge the sinus opening. Many research data confirm that, regardless of the surgical method, as long as the mucosa around the frontal sinus is damaged, the frontal sinus has a tendency to retract itself. Once the mucosa around the frontal sinus is extensively damaged, the frontal sinus should be enlarged as much as possible.

2) Protect the mucosa. The effectiveness of surgery depends largely on the retention of normal mucosa during the operation. The surgeon should read the film carefully and design the surgical plan individually; avoid unnecessary operations as much as possible during the operation. The secretory fluid in the frontal sinus exits the frontal sinus and follows the outer side wall of the frontal recess, and some of it flows into the ethmoidal funnel or into the middle nasal passage through the gap between the upper end of the uncinate process and the middle turbinate; The medial wall re-enters the frontal sinus and participates in the mucus circulation within the sinus. Therefore, the mucosa outside the frontal crypt should be protected.

3) The scope of drug treatment during surgery. Local hormones, long-term low-dose macrolide antibiotics, mucus-releasing agents, and nasal irrigation should be given after surgery. Regular follow-up plays a vital role in the outcome of the disease.

Frontal Sinus Surgery Complications

The complications of nasal endoscopic frontal sinus surgery can be roughly divided into intraoperative complications such as anterior ethmoid artery injury, orbital cardboard injury, and anterior skull base fracture, and postoperative complications such as frontal sinus drainage channel stenosis and atresia and recurrent frontal sinusitis. . The anterior ethmoidal artery originates from the ophthalmic artery, forms a vascular nerve bundle with the anterior ethmoidal vein and anterior ethmoidal nerve, enters the anterior ethmoidal artery, and travels over the posterior and frontal crypts. Injury of the anterior ethmoid artery during surgery may cause intraorbital and intracranial hemorrhage. If post-ball hemorrhage and hematoma occur, it can cause compression of the ophthalmic artery and affect blood supply to the retina. In severe cases, it can affect vision. Generally speaking, due to intraoperative bleeding, unclear anatomical signs, enlarged or lower anterior ethmoidal arteries, etc., all of them cause accidental injury to the anterior ethmoidal arteries, which then affects the anterior ethmoidal arteries. Once the anterior ethmoid artery is damaged, there is no difficulty in compressing or electrocoagulation to stop bleeding. Note that bipolar electrocoagulation should be used to avoid cerebrospinal fluid leakage. Be wary of intraorbital or intracranial hemorrhage that may occur after surgery. If necessary, ask ophthalmology and neurosurgery to assist in diagnosis and treatment. Intraoperative injury of the anterior skull bone caused a fracture, which may cause a cerebrospinal fluid rhinorrhea. During the operation, clear liquid can be seen flowing from the frontal crypt and the leak should be repaired in time to avoid serious consequences.