28 Functional Endoscopic Surgery Flashcards
What is FESS?
What is FESS?
Functional endoscopic sinus surgery. The goal of “functional” endoscopic sinus surgery is to correct underlying anatomic abnormalities or obstructions while preserving mucosa in order to restore mucociliary flow and normal sinus function. The term functional is directly related to techniques used to preserve the natural drainage pathway. The field of rhinology has undergone great advances in recent years with advances in imaging, endoscopic visualization, image guidance, and understanding of the anatomy and pathophysiology of rhinosinusitis.
What is the role of surgical intervention in rhinosinusitis?
What is the role of surgical intervention in rhinosinusitis?
Chronic rhinosinusitis is a medical disease in which surgery may play a role when medical therapy alone is not sufficient. Medical management is the primary, and often only treatment modality in the majority of patients. When medical therapy fails to control symptoms adequately, surgery may be indicated. In cases of chronic or recurrent sinusitis, surgical intervention should be directed at improving the natural drainage pathways of the sinuses. In cases of acute rhinosinusitis, surgical intervention is directed at decompression of the acutely infected sinus associated with possible complications, such as abscess formation.
What measures should be taken prior to surgical intervention for the treatment of rhinosinusitis?
What measures should be taken prior to surgical intervention for the treatment of rhinosinusitis?
A detailed history and physical examination should be performed on any patient to help determine which patients would potentially benefit from surgical intervention. Nasal endoscopy should be performed preoperatively to evalute the specific nasal anatomy along with assessment of the nasal mucosa. Fine cut computed tomography (CT) is an important objective measure performed to identify a patient’s specific anatomy used in preparation for sinus surgery. Imaging should ideally be studied in triplanar (axial, coronal, and sagittal) orientation. As with any surgery, all preoperative medications (including over-the-counter medications) should be discussed with each patient to identify any medications that can increase the risk of bleeding.
What are the main goals of functional endoscopic sinus surgery?
What are the main goals of functional endoscopic sinus surgery?
- Thorough anatomic dissection of the paranasal sinuses to restore the normal drainage pathways. This dissection should be complete and mucosa sparing.
- Avoidance of complications. The paranasal sinuses reside in close proximity to critical structures including the orbit/eye, skull base, carotid artery, and optic nerve.
What are the most common causes of nasal airway obstruction and how are they addressed surgically?
What are the most common causes of nasal airway obstruction and how are they addressed surgically?
Deviated nasal septum and inferior turbinate hypertrophy are two of the most common causes of nasal airway obstruction that can be surgically corrected. Septoplasty is a procedure performed to straighten the deviated septum. Reduction and outfracture of the obstructing inferior turbinates are commonly performed to improve the nasal airway.
How should one proceed through dissection of the paranasal sinuses?
How should one proceed through dissection of the paranasal sinuses?
Based on its anterior location, the maxillary sinus is often addressed first. Osteomeatal complex obstruction is addressed by performing a maxillary antrostomy. The natural ostium of the maxillary sinus is first exposed by removing the uncinate process. Once the natural ostium is identified, it is enlarged as indicated (this ostium is enlarged to include accessory ostia when present).
The anterior ethmoid cells are then adressed by opening the ethmoid bulla. Once this has been completed, one may proceed anterior to posterior in an inferomedial direction. The basal lamella of the middle turbinate is then identified, which is the anatomic division between the anterior and posterior ethmoid sinuses. Proceeding posteriorly from the basal lamella, dissection is then carried posteriorly until the anterior face (rostrum) of the sphenoid sinus is encountered, marking the posterior limit of the posterior ethmoid sinus in the absence of an Onodi cell (posterior ethmoid cell pneumatizing superiorly to the sphenoid sinus).
Medially, the superior turbinate can be used to identify the sphenoid os in the sphenoethmoidal recess. The sphenoethmoidal recess is located inferomedial to the superior turbinate in the vast majority of cases. If necessary, the inferior third of the superior turbinate may be removed to expose the sphenoid ostium. The sphenoid ostium should be enlarged inferiorly and medially to avoid injury to the skull base while avoiding the posterior septal artery (medial terminal branch of the sphenopalatine artery) inferiorly.
The remaining ethmoid partitions are dissected in a posterior to anterior direction from the anterior face of the sphenoid sinus along the ethmoid skull base superiorly with the limits of dissection including the lamina papyracea laterally, middle turbinate medially, and frontal recess anteriorly.
How should one surgically address the frontal sinus?
How should one surgically address the frontal sinus?
Endoscopic frontal sinusotomy has become the standard approach to treating rhinosinusitis involving the frontal recess and sinus. Recent advances in endoscopic visualization and angled instrumentation have improved the surgical treatment of frontal sinusitis. While commonly considered the most difficult sinus to address surgically because of the anterior and superior location, surrounding anatomy and associated risks, endoscopic surgery of the frontal sinus has become increasingly safe and successful. The successive approaches used to improve drainage of the frontal sinus include anterior ethmoidectomy, complete dissection of all anterior ethmoid and frontal cells within the frontal recess (also known as the Draf I procedure), widely opening the frontal ostium (Draf IIa), resection of the floor of the frontal sinus from the nasal septum medially to the lamina papyracea laterally (also known as the Draf IIb procedure), and connection of the two frontal sinuses from orbit to orbit with removal of each frontal sinus floor, inferior portion of the frontal intersinus septum, the superior part of the nasal septum (also known as the Draf III procedure, modified Lothrop, or transseptal frontal sinusotomy). External or open approaches may be used in select cases including a trephine, Lynch incision, or bicoronal flap with osteoplastic flap, which can be used for tumor removal, cranialization or obliteration procedure.
What is a common reason for surgical failure of the maxillary antrostomy?
What is a common reason for surgical failure of the maxillary antrostomy?
Failure to incorporate the true maxillary ostium located anterosuperiorally with the surgical antrostomy, resulting in two separate openings. This is a setup for recirculation of mucus from the natural ostium to the surgical ostium resulting in dysfunction and stasis of secretions within the maxillary sinus.
What are the four lamellae that serve as anatomic landmarks to complete a sinus surgery?
What are the four lamellae that serve as anatomic landmarks to complete a sinus surgery?
- First lamella: Uncinate process
- Second lamella: Ethmoid bulla
- Third lamella: Basal lamella of the middle turbinate (horizontal component of the middle turbinate; this represents the anatomic division between anterior and posterior ethmoid air cells)
- Fourth lamella: Superior turbinate
What are common minor complications of sinus surgery?
What are common minor complications of sinus surgery?
Bleeding, hyposmia/anosmia, numbness, nasal obstruction, and adhesions. It is normal to have small amounts of bleeding after sinus surgery which rarely (less than 1%) requires intervention. Preoperative evaluation and discussion of all medications (prescription, over-the-counter, and supplements) known to cause increased bleeding and strict adherence to the principles of hemostasis can help minimize the bleeding risk. Hyposmia and rarely anosmia can occur. Although this is generally considered a minor complicaiton, it can be quite distressing to the patient. Care to avoid overdissection of the superior aspects of the middle and superior turbinates and mucosal stripping within the olfactory cleft can help prevent this. Infection, allergy, and the presence of nasal polyps can lead to impaired sense of smell postoperatively. An important point to discuss with patients is that decreased sense of smell preoperatively may or may not improve postoperatively. Numbness of the nose, upper lip, or central upper teeth can occur postoperatively but is usually self-limited. Nasal obstruction and pain are common self-limited minor complications. Postoperative crusting and adhesions may occur in both the nasal cavity and paranasal sinuses, which should be debrided during early postoperative visits to prevent mature scar formation and potential resultant dysfunction. This complication can be mitigated by performance of frequent postoperative saline irrigations by the patient and close endoscopic evaluation and debridement by the surgeon.
What are the major complications of sinus surgery?
What are the major complications of sinus surgery?
Orbital injury, intracanial injury, and hemorrhage. The medial orbital wall, or lamina papyracea, is the lateral boundary of the ethmoid sinus. This close proximity of the orbit to the paranasal sinuses makes orbital injury an inherent risk. The lamina papyracea separating the ethmoid sinuses from the orbit is one of the thinnest bones in the human body. Transgression of this bone and bleeding into the bony orbit can cause complications ranging from periorbital ecchymosis and emphysema to orbital hematoma and blindness. Anisocoria, ophthalmoplegia, and proptosis are ominous signs demanding prompt action. In cases of increased orbital pressure, steroids, mannitol, and/or orbital decompression via lateral canthotomy and cantholysis or endoscopic decompression should be performed immediately to relieve the pressure and preserve vision. Damage to the extraocular muscles, most commonly the medial rectus, can occur, leading to permanent diplopia. Overly aggressive anterior dissection of the maxillary antrostomy can result in injury to the nasolacrimal system. Injury to the lacrimal system can result in epiphora or recurrent dacryocystitis, and may require correctional surgery.
Intracranial complications can occur because of the proximity of the skull base to the frontal, ethmoid, and sphenoid sinuses. The bone separating the paranasal sinus from the intracranial cavity is also very thin, on the order of millimeters. Injury most commonly occurs at the cribriform plate and roof of the ethmoid sinus where the bone is thinnest. Complications associated with intracranial entry include CSF leak, meningitis, carotid artery injury, tension pneumocephalus, and direct brain injury. Intracranial entry should be identified immediately and repaired.
Injury to the ethmoidal, sphenopalatine, or internal carotid arteries (ICA) can result in major hemmorhage. In the case of ICA injury, stroke and death are possible. Direct endoscopic repair of an ICA injury is technically difficult given the high-flow bleeding and difficult visualization. Management typically involves aggressive packing to tamponade the hemorrhage, and transfer to interventional radiology for possible ICA embolization. Injury to the anterior ethmoidal arteries along the skull base can result in intracranial hemorrhage as well as intraorbital hematoma and resultant blindness. The internal maxillary artery courses behind the posterior wall of the maxillary sinus within the pterygopalatine fossa. Its terminal branch, the sphenopalatine artery, exits into the nose through the sphenopalatine foramen into the inferior portion of the basal lamella of the middle turbinate. Injury to the artery can result in significant epistaxis.
What does IGS stand for and what are the indications for use?
What does IGS stand for and what are the indications for use?
Image guided surgery (IGS) is a computerized navigation system that tracks surgical instruments in space using a patient’s preoperative CT (or MRI) scan and displays the instrument location in a triplanar (axial, coronal, and sagittal) fashion. Indications include: nasal polyps, revision sinus surgery, frontal or sphenoid surgery, orbital surgery, surgery for skull base disorder, or CSF leak. IGS is never a substitute for the surgeon’s anatomic knowledge.
What type of general anesthesia has been shown to improve visualization in sinus surgery?
What type of general anesthesia has been shown to improve visualization in sinus surgery?
Total intravenous anesthesia (TIVA). TIVA has been shown to improve the surgical field visualization by correlating decreased heart rate and improved surgical field visualization with decreased blood loss. A lower heart rate has the added benefit of lower mean arterial pressures, avoidance of excess fluid shifts, and lower central venous pressures. Avoidance of inhalational anesthetics prevents the peripheral vasodilation that accompanies these agents.
How does patient positioning affect visualization?
How does patient positioning affect visualization?
Elevation of the patient’s head, or reverse Trendelenberg positioning, has been shown to improve the surgical field visualization.
How do topical medications affect sinus surgery?
How do topical medications affect sinus surgery?
Nasal pledgets soaked in oxymetazoline, neosynephrine or epinephrine (1:1000) can be placed into the nasal cavity to cause vasoconstriction and help improve generalized mucosal oozing. They carry a low complication rate (0.001%) but should be used with caution in pediatric patients and patients with cardiovascular risks or hypertension.
What radiologic staging system is sued to assess the ethmoid skull base?
What radiologic staging system is sued to assess the ethmoid skull base?
The Keros classification is a method of classifying the depth of the olfactory fossa. The depth of the olfactory fossa is determined by the height of the cribriform plate and is staged into three categories: Type 1 has a depth of 1 to 3 mm (26% of the population), Type 2 has a depth of 4 to 7 mm (73% of the population), and type 3 has a depth of 8 to 16 mm (1% of the population).
