15 Surgery of the Ethmoid, Maxillary, and Sphenoid Sinuses Surgery of the paranasal sinuses is one of the most common procedures in modern otolaryngologic practice, which reflects the high prevalence of chronic rhinosinusitis in developed countries.1 The widespread use of nasal endoscopy in contemporary practice has resulted in the acceptance of endoscopic sinus surgery (ESS) as the standard of care for the great majority of surgical indications. Moreover, an appreciation of normal sinus anatomy and function, beginning with the work of Messerklinger and Wigand et al, has led to the adoption of ESS in context of functional preservation.2,3 The principles of functional ESS are based on certain theoretical considerations: (1) sinusitis is rhinogenic in origin and (2) recurrent sinusitis is usually because of stenosis at the ostiomeatal unit. The additional assumption that inflammation most commonly affects the ethmoid sinus implies that the failure to successfully treat pansinusitis is usually because of the inadequate treatment of ethmoidal sinusitis.4 A contemporary discussion of paranasal sinus surgery should focus on preserving normal function and limiting dissection to include only diseased structures. The primary goal of functional ESS is the restoration of physiological drainage and ventilation patterns, and is by definition a limited surgery. A secondary goal is to create a pathway for the application of topical intranasal sinus therapy, which is routinely practiced in many patients with chronic rhinosinusitis. This is especially germane for individuals with medical conditions that affect mucociliary flow and mucus formation. Adherence to the principles of sound surgical technique is of central importance to surgery of the paranasal sinuses. Foremost among these principles is a mastery of the pertinent anatomy, which begins with cadaveric study and continues with a stepwise progression of clinical experience. The second principle is obtaining excellent visualization of the surgical target and surrounding structures, which is facilitated by modern fiberoptic endoscopes that provide a view that is both panoramic and microscopic. The third principle is the maintenance of thorough hemostasis throughout the operation. Methods for achieving hemostasis include pressure, pharmacological vasoconstriction, promotion of the clotting cascade, and direct surgical cautery. The fourth principle is minimization of trauma to normal tissue. Unnecessary trauma to nasal mucosa is likely to impair postoperative function and counters attempts at maintaining intraoperative hemostasis. As the utilization of ESS has increased, several conventional sinus surgery techniques have fallen out of favor. These operations, developed in the preantibiotic era, were designed to exenterate infections but left a cicatrix-filled sinus cavity without mucociliary function in many patients. Therefore, the following techniques should be reserved for clinical scenarios where ESS is not practicable. External ethmoidectomy remains an acceptable treatment for acute subperiosteal abscess when endoscopic capability is not available. This approach uses a Lynch incision near the medial canthus to access the lamina papyracea through a transorbital route. This is also the traditional approach for ligation of the anterior and posterior ethmoidal arteries. The disadvantages of this technique include an external scar and poor visualization of the adjacent sinuses, and it is not suitable for the routine treatment of chronic rhinosinusitis. Intranasal ethmoidectomy with a speculum and headlight was the preferred method before the availability of nasal endoscopes.5 Direct access to the ethmoid sinuses was possible, although visualization was limited without sacrifice of the middle turbinate. This technique is limited by imprecise hemostasis and confinement to one-handed operation while the other hand wields the nasal speculum. In addition, the optics are limited by a narrow view through the nares and a proximal light source, in contrast with ESS, in which the fiberoptic endoscope provides a distal light source. The use of the endoscope enhances visualization of the surgical field and permits the surgeon to operate precisely at the surgical site and recreate normal physiologic function. Inferior meatal antrostomy was historically performed in the routine treatment of acute maxillary sinusitis. However, while the creation of a nonphysiological antrostomy provides ventilation, it does not permit restoration of normal mucociliary clearance. Therefore, it is not a reliable alternative to middle meatal antrostomy in functional surgery for the treatment of chronic rhinosinusitis.6 This technique, also known as the Caldwell-Luc procedure, requires a sublabial incision with permanent removal of bone over the canine fossa. As with the inferior meatal antrostomy, this operation does not restore the normal physiological condition that is required for the functional treatment of chronic rhinosinusitis. Its use in contemporary practice may be best suited for the extirpation of solid matter, such as a mycetoma or inverted papilloma, which cannot be removed by an endonasal approach.7 Preoperative computed tomography (CT) imaging is mandatory in the work-up of a patient with rhinosinusitis for whom surgery is being considered. Dedicated coronal, sagittal, and axial views of the paranasal sinuses are preferred. Careful interpretation of the films by the operating surgeon will reveal areas of anatomical variability, bony erosion, and mucocele formation, and will help prevent surgical complications. The preoperative CT scan may be obtained using one of several acquisition protocols for use with a commercially available system for intraoperative navigation.8 Familiarity with rigid fiberoptic nasal endoscopes is essential for performing ESS. Rigid scopes can be operated with the nondominant hand while surgical instruments can be used simultaneously by the dominant hand. This technique permits the surgeon to dynamically control the field of view during the procedure, which effectively compensates for the absence of stereoscopic vision. The 0-degree endoscope provides a circumferential view and is usually preferred for nasal preparation and the initial surgical steps. Endoscopes angled at 30, 45, and 70 degrees are valuable for providing a direct view of the ostia of the frontal and maxillary sinuses. New endoscopes have also been introduced, which provide variable optical deflection using a single instrument (Acclarent, Menlo Park, California; Karl Storz, Tuttlingen, Germany). Surgical instruments for endoscopic surgery generally consist of probes, punches, and forceps. Probes include the angled frontal and maxillary sinus probes, olive-tipped suction cannulas, and the von Eicken antrum cannula. The Freer elevator is a versatile instrument that can be used to medialize or lateralize turbinates and to advance cottonoids or other adjunctive materials into the desired location. Punches include the straight and angled true-cut punch, the Grunewald punch, mushroom punches, back-biting antrum punches, and Kerrison rongeurs. Forceps include the bayonet, Takahashi, Blakesley-Wilde, and Janson-Middleton. Tissue shavers and drills have a role in ESS in certain scenarios. Use of a tissue shaver or microdebrider may aid in shortening operative time in patients with massive polyposis or in whom mucosal edema is severe. Similarly, performance of an uncomplicated ESS may be expedited by the use of powered instrumentation. When hyperostotic chronic rhinosinusitis is present, the presence of thick bony septations may require the use of a high-powered endoscopic drill. While powered instrumentation adds the benefit of speed and internal suction, the potential for propagation of inadvertent intracranial or orbital injury suggests that these instruments should be reserved for use in experienced hands.9,10 Electrosurgical equipment has a limited role in ESS. Regardless, a variety of endoscopic attachments are available for use with unipolar and bipolar cautery, which may be useful if bleeding from a discrete arterial vessel is present. Blind cauterization of mucosal bleeding is generally an ineffective enterprise. The recent introduction of specialized balloon catheter systems for sinus dilation has expanded the instrumentation available to the endoscopic sinus surgeon (Acclarent; Entellus Medical, Plymouth, Minnesota). Variable angulation of the catheters permits access to the frontal, maxillary, and sphenoid sinuses under endoscopic guidance. Observational studies have suggested that dilation of sinus ostia without tissue removal is effective in some patients with chronic rhinosinusitis.11,12 Further study is needed to determine the appropriate role of these instruments in the treatment of paranasal sinus disease. A variety of nondurable surgical supplies are available as surgical adjuncts. Cottonoid pledgets can be used liberally throughout the operation to provide focal hemostatic pressure and to apply pharmacological agents. Topical application of thrombin, with or without epinephrine, is a useful strategy to prevent intraoperative and postoperative bleeding. Dissolvable hemostatic agents such as Surgicel (Ethicon Inc., Somerville, New Jersey), Surgiflo (Ethicon), and FloSeal (Baxter, Deerfield, Illinois) may be useful for maintaining hemostasis at the conclusion of the case.13–15 A variety of dissolvable and nondissolvable packing materials are available, although their necessity has not been well established.16 Drug-eluting stents have been recently introduced and remain on the horizon of potential adjuncts. The majority of individuals undergoing ESS are otherwise healthy and are at low risk for anesthetic complications. Nevertheless, discussion with the practitioner administering anesthesia during the procedure is advisable in the event that unforeseen circumstances arise. In particular, patients with chronic upper airway obstruction, such as from nasal septal deviation or severe nasal polyposis, may have signs of upper airway resistance syndrome. Such patients may benefit from alternate anesthetic regimens, nonnarcotic analgesia, and overnight postoperative monitoring. General anesthesia is preferred for all forms of paranasal sinus surgery, although monitored sedation with local anesthesia may be considered for limited surgery in patients for whom the risk of general anesthesia is considered unacceptable.17 Advantages of general anesthesia include efficiency, reduced pain perception, controlled ventilation, and avoidance of aspiration. Endotracheal intubation is the standard for airway control, although use of the laryngeal mask airway has been adopted by some practitioners.18 Blood pressure should be maintained near hypotensive range to facilitate intraoperative hemostasis.
Surgical Principles
Nonendoscopic Procedures
External Ethmoidectomy
Intranasal Ethmoidectomy
Endonasal Inferior Meatal Antrostomy
Sublabial Maxillary Antrostomy
Operative Planning
Imaging and Navigation
Instrumentation
Endoscopes
Nonpowered Instrumentation
Powered Instrumentation
Balloon Technology
Adjunctive Materials
Anesthesia
Endoscopic Techniques
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