The sinuses, also known as the sieve vagus, are the most complex bony structures in the human anatomy, especially because of their close and intricate anatomical relationship with their surroundings, as well as the multiple variations and pneumatization of their own anatomical form, making sinus surgery a difficult and risky and dangerous procedure. For example, the anatomy adjacent to it includes the anterior cranial recess, sieve plate, internal carotid artery, cavernous sinus, orbital and orbital contents, optic nerve, and numerous large arteries (ophthalmic, pterygopalatine, internal carotid). Familiarity with the anatomy and repeated preoperative studies of the CT films, and familiarity with the anatomical structures and their interrelationships are essential to avoid surgical complications.
During the FESS procedure, the surgical field of view is variable and narrow, and the anatomical variants that are quite common make surgical landmarks difficult to identify. In addition, the surgeon’s view is limited to the mucosal surface, and the surgeon cannot view the structures and lesions behind the mucosa, posing many risks of blindness. If the patient’s anatomical variation is not fully understood and estimated before surgery, complications are likely to arise during surgery. Therefore, a detailed surgical “roadmap” is essential. All patients requiring FESS must have a preoperative coronary CT. The coronal CT film is an important reference for surgical planning.
Surgical principle: skilled anatomy, prefer right to left.
Anatomical factors: 1. Normal anatomical weaknesses: nasal apex, septal sinus apex, nasal apex septal sinus apex junction, etc.
2.Anatomical variation: sulcus connected to the paper-like plate, paper-like plate absence, Haller’s airspace (infraorbital airspace), Onodi’s airspace (supra-parietal septum), large septum, etc.
3. Re-operation: anatomical changes, bone sclerosis, easy bleeding, poor anesthesia, etc.
Operative factors: unskilled, too bold, no supervision.
Instrument factors: unclear images, inappropriate surgical instruments, poor hemostatic measures, etc.
Other factors: inadequate preoperative preparation, unclear intraoperative visualization, excessive bleeding, poor anesthesia.
Classification of complications (a) By site: 1. Nasal complications: such as nasal bleeding, postoperative nasal adhesions, etc. 2.
2. Ocular complications: such as orbital periosteal emphysema, complete injury of cardboard and orbital periosteum, subconjunctival hemorrhage or hematoma, ocular motility disorder, optic nerve injury, etc.
3, brain complications 4, other: toothache, etc.
(ii) By severity: Usually, they can be divided into two categories: general and severe. General complications include orbital periosteal emphysema, nasal bleeding, postoperative nasal adhesions, toothache, etc. Although these complications are more common, they often heal spontaneously and do not require CT examination. Serious complications are less common, but are often severely devastating or even fatal.
The more common serious complications are: 1. Complete injury to the paper plate and orbital periosteum: this can lead to herniation of the orbital fat into the septal sinus. Pre-existing orbital cardboard defects may be caused by the patient’s previous history of trauma or chronic sinusitis erosion; cardboard damage due to trauma during surgery is mainly due to inadvertent force during removal of the middle turbinate substrate attachment.
If there is a pre-existing orbital cardboard defect or if previous surgery has caused damage to the cardboard, there is a risk of direct injury to the medial rectus, superior oblique muscles, or other orbital contents during surgery. The result of damage to the orbital contents may lead to postoperative diplopia, which may be caused by a fragment of bone stuck in the muscle, direct tearing of the muscle, or secondary nerve damage. Axial and coronal CT scans of thin sections can help us understand the condition of the cardboard preoperatively and avoid the above complications.
2. Subconjunctival hemorrhage or hematoma: often accompanied by injury to the extraocular muscles. CT shows high density shadows in the orbit and displacement of the orbital contents by pressure.
3. Optic nerve injury: If the bony wall of the optic nerve canal is damaged when doing posterior group septal sinus resection, it may lead to temporary postoperative visual impairment or even permanent visual impairment. The trauma causes impaired blood supply to the optic nerve, which can also lead to blindness. In cases of postoperative visual impairment, CT examinations can visualize orbital wall damage, abnormal shadows in the orbit, displacement of orbital tissues, and the extent of compression. Further establish whether there is damage to the optic nerve, the possibility of vision recovery and the need for immediate surgery.
4. Injury to large blood vessels: direct injury to important blood vessels can cause massive intraoperative bleeding. If the internal carotid artery is directly injured it can even lead to the patient’s death. Emergency angiography should be done and a balloon should be placed to occlude the injured artery.
5. Subarachnoid hemorrhage: If the patient has headache, photophobia, or if the patient shows signs of subarachnoid hemorrhage, a CT scan of the head should be done immediately.
6. Injury to the nasolacrimal duct: Most of them occur during maxillary sinus-middle nasal passage opening, when the opening of the maxillary sinus is enlarged forward. The membrane of the nasolacrimal duct may heal spontaneously or be relieved by the spontaneous formation of a fistula in the middle nasal passage.
7. Postoperative cerebrospinal fluid leak: It is one of the serious complications of FESS and often occurs due to careless penetration of the dura mater during operation. CT scan, especially sagittal CT synthesis, can clearly show the site of cerebrospinal fluid leakage, and if combined with magnetic resonance, it can help to locate, characterize, and determine the size and extent of the leak.
8. Brain injury: brain injury is the most dangerous complication, and CT passage can confirm the diagnosis.