42 Revision Surgery of the Frontal Sinus Frontal sinus surgery has challenged otolaryngologists for more than a century. Today, modern endoscopic frontal recess surgery is widely considered to be one of the most difficult procedures otolaryngologists perform; revision frontal surgery is even more challenging. Adding to the difficulty, the underlying conditions are recalcitrant in nature, and patients are often exasperated, having subjected themselves to many medical and surgical treatments without substantial relief. The regional anatomy, technical aspects of frontal sinus surgery, and recalcitrant nature of sinusitis make caring for patients with frontal disease through surgery a formidable task. The trials and tribulations of frontal sinus surgery have been well documented and will not be reviewed here. The focus of this chapter will be revision surgery of the frontal recess in the modern endoscopic era. Revision surgery of the frontal sinus is indicated for a variety of conditions. Common indications include persistent disease following incomplete initial surgery, iatrogenic disease due to scarring with osteoneogenesis, and recurrent chronic sinus disease. Typically, revision surgery is considered when a patient complains of significant symptoms, such as headache, facial pain, retro-orbital pain, nasal congestion, and postnasal drainage, which do not respond to medical therapy. Medical therapy includes antibiotics for infectious sinusitis and oral corticosteroid tapering regimens for inflammatory, allergic, and eosinophilic-type sinusitis conditions. The evaluation for revision surgery includes a thorough medical history, a detailed diagnostic sinonasal endoscopy, and a computed tomography (CT) scan. A CT scan can be especially useful in gaining insight into the cause of the frontal problem, such as frontal sinus outflow tract obstruction secondary to the presence of osteoneogenesis. Iatrogenic frontal sinusitis is a significant condition, one that is best prevented rather than treated. Prevention cannot be stressed enough, and it begins with an accurate diagnosis. If the diagnosis of sinusitis and the indications for surgery within each sinus are considered, the chance for unnecessary surgery and iatrogenic disease can be greatly reduced. Often when cases of iatrogenic frontal sinusitis are analyzed, it is evident that disease was limited initially to the osteomeatal complex and ethmoidal prerecess area, yet surgery was performed far up into or through the internal os of the frontal sinus; that is, the frontal sinus was radiographically normal, the patient had no or few symptoms referable to the frontal sinus, yet surgery was performed. This “while we are in there” approach to surgical indications for the frontal sinus can have lifelong deleterious consequences. Such an approach to surgery is not employed in other areas of the body. We would shudder if, while replacing a fully diseased knee, an orthopedist recommended a prosthesis for a normal or minimally diseased contralateral hip. Similarly, it would not be acceptable for a cardiac surgeon to replace a normal mitral valve during aortic valve replacement for advanced aortic valve disease. Iatrogenic frontal sinus disease can be prevented by carefully considering the indications for endoscopic frontal sinus surgery and the scope of the procedure. Another critical area to consider is the individual patient’s pathophysiology. Far too often we attribute sinus disease to “obstruction” and apply surgical principles to “relieve obstruction” and “facilitate drainage.” Thereafter, in consultation for revision frontal sinus surgery, sinonasal tissue inflammation, not obstruction, is observed on endoscopy. A prolonged course of oral corticosteroids can bring about dramatic control of the primary disease process. The degree of disease resolution can be equal to or exceed that which is achieved with surgery. (This can be humbling to observe as a surgeon.) With continued follow-up, the disease recurs but can again be controlled with corticosteroid retreatment. Over time, it becomes clear that the disease is not related to ostial obstruction and does not require a “relief of ostial obstruction” solution. Rather, it is an inflammatory condition of the sinonasal membrane, a medical disease; hence, it responds to a medical solution. Unfortunately, our current medical armamentarium is largely limited to oral corticosteroids. These agents are not desirable on a long-term basis due to their side effects and potential adverse effects. Clearly, more acceptable medications need to be discovered. Until such time, surgery may be used as a last resort. However, it should be recognized that often surgery is recommended because of a lack of alternative treatment options, not a logical application based on the pathophysiology. If surgery is limited to disease sites that are refractory to medical therapy (antibiotics for bacterial disease, oral corticosteroids for eosinophilic inflammatory disease), and mucosal sparing surgical principles are maintained, patients can benefit from future discoveries in medical therapy. If aggressive surgery to relieve obstruction of the frontal recess is performed for mucosal membrane/medical disease and an iatrogenic obstruction results, the patient will not benefit from additional advances in medical care. The basic principle “First do no harm” has a central place in the surgical care of the frontal recess and sinus. In addition to careful case selection, several technical considerations are important for preventing iatrogenic frontal sinusitis. Mucosal sparing within the recess is critical for avoiding postoperative stenosis and osteoneogenesis. Mucosal-sparing forceps, ostial seekers, and curets designed especially for the frontal recess allow disease and ethmoid septations to be removed without mucosal stripping. Fracture or partial resection of the middle turbinate can be associated with lateralization of tissue and frontal sinus obstruction. Lamina orbitalis (papyracea) removal can be associated with medialization of orbital fat across the frontal sinus and subsequent frontal obstruction. An appreciation of adjacent structures is necessary before attempting operative dissection in the frontal recess. The superior portion of the uncinate process is intimately related to the frontal recess and sinus. This portion of the uncinate extends superiorly behind the attachment of the middle turbinate and commonly curves laterally to insert on the lamina papyracea. The air space just below this insertion is termed the recessus terminalis, and the frontal recess is located superomedial to the uncinate insertion. The frontal sinus will drain and ventilate medial to the uncinate process. Less frequently, the uncinate inserts on the middle turbinate or the skull base. In these cases, the frontal recess communicates with the ethmoid infundibulum, and the frontal sinus drains lateral to the uncinate process.1 The medial extent of the frontal recess is usually formed by the vertical lamellar portion of the middle turbinate. The lateral extent of the frontal recess is the lamina orbitalis (papyracea). Its anterior limit is the agger nasi region. The posterior limit of the recess is variable, but in general, the posterior boundary is formed by the anterior wall of the ethmoid bulla. The complexity of the frontal recess cannot be fully appreciated without consideration of the myriad of ethmoid cells that may pneumatize and drain into this area.2 The agger nasi region, a prominence found superiorly in the lateral nasal wall just anterior to the insertion of the middle turbinate, is frequently pneumatized by an anterior ethmoid cell. When present, this cell (or cells) can significantly affect the shape of the anterior aspect of the frontal recess and form a portion of the anterior floor of the frontal sinus. Supraorbital ethmoid cells are ethmoid cells that ascend and pneumatize into the orbital plate of the frontal bone (pars orbitalis). They typically drain posterior to the frontal recess and sinus. On CT scan, supraorbital ethmoid cells can give the appearance of a duplicate frontal sinus and need to be considered carefully in both primary and revision surgery.3 Another type of ethmoid cell affecting revision frontal sinus surgery is the frontal cell. This cell is located above the agger nasi cell and can extend into the frontal sinus to varying degrees. At times these cells also can give the appearance of a duplicate frontal sinus. They can contribute to frontal recess and sinus obstruction, and their bony walls may need to be addressed in revision frontal surgery. The goals in revision endoscopic frontal sinusotomy are restoration of normal frontal sinus function and sinus health. The narrow confines of the frontal recess present a technical challenge for the surgeon. Identifying the middle turbinate, agger nasi region, medial orbital wall, and skull base provides surgical orientation within the frontal recess. The skull base can be identified posteriorly in the ethmoid cavity and followed forward as it slopes upward into the frontal recess. Usually, the anterior ethmoid neurovascular bundle is located in the area where the skull base transitions from a horizontal orientation to a more vertical orientation in the frontal recess. The area of the frontal sinus ostium is identified and carefully widened. Attempts should be made to avoid circumferential dissection near the ostium to prevent circumferential stenosis.
Indications for Revision Frontal Sinus Surgery
Management of Frontal Sinus Disease following Surgery
Prevention
Revision Frontal Sinus Surgery
Anatomical Considerations
Revision Endoscopic Frontal Sinusotomy
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