Basic Surgical Techniques in Endoscopic Sinus Surgery
Summary
Patients with chronic rhinosinusitis (CRS) who have not responded to maximal medical therapy are commonly managed surgically. The majority of these patients present with disease in the maxillary and ethmoid sinuses and can be managed with basic endoscopic sinus surgery (ESS) techniques directed to these sinuses. In this chapter, we discuss the indications for surgery, detailed techniques, possible complications, and outcomes of surgery.
Introduction
Rhinosinusitis encompasses a wide spectrum of inflammatory and infective conditions of the nose and paranasal sinuses, which range in duration and severity from the ubiquitous common cold to CRS and life-threatening ascending orbital and intracranial infections, respectively.1 Rhinosinusitis is primarily a clinical diagnosis ( Table 19.1 ) and can be classified as acute or chronic based on whether the symptoms last for less or more than 12 weeks.
There is a paucity of reliable epidemiological data for both acute and chronic rhinosinusitis. Acute rhinosinusitis (ARS) has been reported to affect 8.4% of the general population and to account for 2% of visits by men and 3.3% of visits by women to a general practitioner.1 ARS is managed medically in the overwhelming majority of cases; it is the reason for 9% of pediatric and 21% of adult antibiotic prescriptions,2 but leads to < 0.007% of hospital admissions.
CRS has an incidence of 11% (range 7–27%) in the general population.3,4 Its first-line management is also medical, with most patients receiving the combination therapy of nasal douching and topical corticosteroids in addition to long-term antibiotics if considered necessary.1 For patients with concomitant nasal polyposis, a course of oral corticosteroids may also be considered.1 Those patients who fail to respond to maximal medical therapy are considered for sinus surgery. This chapter provides an overview of the common surgical techniques used for the endoscopic treatment of rhinosinusitis.
Indications/Patient Selection
The most common indication for performing ESS is CRS with or without nasal polyposis ( Figs. 19.1 and 19.2 ) following failure of aggressive medical therapy. Preoperative computed tomography (CT) is mandatory for confirming sinus mucosal disease and for delineating variations in surgical anatomy that can affect operative safety. It is essential when planning surgery that it be tailored to the extent of disease and specific sinuses involved. Those patients with persistent symptoms of rhinosinusitis and consistent CT findings after medical therapy ( Fig. 19.3 ) are candidates for sinus surgery.
Note
Sinus surgery is indicated for patients with CRS with or without nasal polyposis who fail to respond to medical therapy.
Tips and Tricks
Assess the height of the lateral lamellae of the cribriform plate and the presence of atypical cells (infraorbital, sphenoethmoidal, or frontal cells). In sagittal images, the slope of the skull base can be identified and the frontal recess anatomy noted. Frontal sinus drainage should also be reviewed in axial images.
Patient Information/Consent
Paranasal sinus surgery is performed in close anatomical proximity to vital structures, including the brain, orbits, and carotid arteries, and although the risk to these structures is very low, given the potentially grave consequences it is mandatory that patients are made aware of both the common and the rare but potentially life- and vision-threatening risks of sinus surgery. We provide our patients with a standardized list of the surgical risks and provide a more detailed and itemized explanation of these risks in the patient information sheet ( Table 19.2 ).
Patient Positioning and Anesthesia
Surgery is performed under local or general anesthesia (see Chapter 30) with the patient in the supine position. The airway is secured with a classic laryngeal mask airway, and a throat pack is inserted if preferred. The alternative is to use an endotracheal tube, which, in the authors’ practice, is mostly used in patients with underlying lung disease (e.g., cystic fibrosis [CF]) where high ventilatory pressures are anticipated. The nose is then decongested. (For details on local anesthesia, see Chapter 30.) Different preparations can be used to achieve this; we favor Moffat′s solution (2 mL of 10% cocaine, 1 mL of 1:1000 adrenaline, and 2 mL of sodium bicarbonate) applied on nasal Merocel dressing or sprayed into the nasal cavity. The positions of the patient, surgeon, camera system, and, when present, sinus navigation system are shown in Fig. 19.4.
Basic Surgical Instruments for Endoscopic Sinus Surgery
The endoscopes used routinely during surgery include 0-, 30-, 45-, and occasionally 70-degree Hopkins rods. Recently, an endoscope with variable angles from 10 to 90 degrees has become available and may in the future replace the use of multiple endoscopes. The main types of instruments used in ESS are soft tissue elevators, bone curettes, suction, sinus probes, bone/soft tissue punch forceps and through-cutting instruments. These instruments have been designed and angulated to provide optimal access to the different sinuses ( Fig. 19.5 ). In general, through-cutting instruments are preferred to grasping forceps (e.g., Blakesley forceps) when removing soft tissue or bone to avoid mucosal stripping or uncontrolled bone fracturing. In addition to these, powered microdebriders are frequently used in basic sinus surgery. By providing concurrent cutting and suction, the surgeon can achieve polyp and diseased tissue removal with minimal mucosal stripping. Many endoscopic surgeons use the microdebrider for the initial bone and soft tissue removal during ethmoidectomy and handheld through-cutting forceps to complete the dissection when close to the skull base and orbit. Descriptions of more specialized instruments designed predominantly to be used for extended applications of sinus surgery are beyond the scope of this chapter.
Tips and Tricks
Use the 0-degree endoscopes until the essential landmarks have been identified; angled endoscopes can then be used as needed.
Operative Steps
The principal objective of sinus surgery is to reestablish unimpeded mucociliary flow and remove irreversibly changed mucosa and, when present, nasal polyps. Maxillary, frontal, and ethmoid sinuses physiologically drain to the region of the ostiomeatal complex (OMC), which is bound anteriorly by the uncinate bone, laterally by the lateral nasal wall, superiorly and posteriorly by ethmoid air cells, and medially by the medial aspect of the middle turbinate. The first step of surgery is therefore to gain access to this region.
Tips and Tricks
The extent of surgery reflects the extent of disease.
Caution
If excessive bleeding is difficult to control during surgery, it is best to err on the side of safety and stop the operation.
Establishing and Optimizing Access to the Ostiomeatal Complex
Access to the OMC complex is achieved through the middle meatal cleft ( Fig. 19.6 ); this is helped by maximal decongestion. Decongestion is preferably initially performed in the anesthetic room, then by placement of 1:10,000 adrenaline-soaked Merocel sponges in the nasal cavity and under the middle turbinate. In some cases, access is hindered by a deviated nasal septum or paradoxical curvature ( Fig. 19.6a ) or pneumatization ( Fig. 19.7 ) of the middle turbinate.
In our experience, some patients require additional surgical maneuvers to optimize access. This includes septoplasty (3%), partial middle turbinectomy (3%), and concomitant septoplasty and partial middle turbinectomy (1.5%). Care must be exercised not to amputate the middle turbinate, as it is the key landmark for the sinuses, and its removal makes any subsequent surgery riskier. When indicated, only partial resection of the middle turbinate should be performed, with the aim to preserve the horizontal attachment and anterior buttress. A severely polypoid or unstable turbinate with risk of lateralization is a common indication for resection. When there is a risk of olfactory obstruction by a scarred turbinate, resection is indicated.
Tips and Tricks
Minimize bleeding by preparing the nose with Moffat′s solution or equivalent and the intraoperative use of Merocel sponges soaked in 1:10,000 adrenaline placed into the middle meatus.
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