Frontal sinus instrumentation

In the era of external sinus surgery, access to the frontal sinus was very straightforward. Its position high in the frontal bone allowed relatively safe approaches to the anterior table, which would be removed in a variety of fashions. The osteoplastic fl ap with obliteration gained acceptance in the 1950s as the standard of management in chronic frontal sinus infl ammatory conditions [11]. Its purpose was to make the sinus nonfunctional and no longer an issue. From an instrumentation standpoint, no specialized equipment was needed to approach this relatively superfi cial structure. The fi rst specialized instrument designed specifi cally for use in the frontal sinus was the Van Alyea cannula (Fig. 3.1), which was used for transnasal irrigation of the frontal sinus in patients that had not been operated on. The introduction of endoscopic sinus surgery brought about a paradigm shift in sinus surgery and a renaissance to the study of sinus anatomy and physiology. Using endoscopic methods, surgeons began to treat chronic infl ammatory disease in a functional manner rather than in an extirpative or obliterative manner. They sought to preserve the anatomy and enhance the natural drainage pathways of the paranasal sinuses [28]. As all prior transnasal sinus instrumentation was designed to be used with a speculum and headlight, the advent of endoscopic sinus surgery necessitated the development of new instrumentation, which would complement endoscopy. While the maxillary, ethmoid, and sphenoid sinuses can be approached with straight instrumentation and 0° endoscopes, the frontal sinus drainage pathway lies at an upward angle to the anteroposterior axis of the ethmoid sinuses. It is above and behind the insertion of the middle turbinate attachment to the lateral nasal wall. Standard instrumentation would allow neither access nor safe removal of tissue in this area. In 1989, Kuhn and Bolger developed frontal sinus instruments with Karl Storz (Tuttlingen, Germany) that would allow safe dissection in this area. This set, known as the Kuhn-Bolger Frontal Sinus Instrument Set, consists of two frontal sinus curettes, one frontal ostium seeker, and six frontal recess giraff e forceps (Fig. 3.2). These advances in instrumentation and the operative techniques associated with them [2, 3, 7, 12, 14, 16, 18, 19, 21, 27] allowed better success in the frontal recess, and endoscopic frontal sinusotomy became the standard for the primary operative management of chronic frontal sinusitis. The anatomy of the frontal recess is discussed elsewhere in this publication;, it is an inverted funnelshaped area, which extends from the internal frontal ostium down along the skull base ending at the anterior ethmoid artery (Fig 3.3). It is extensively and variably pneumatized by a variety of frontal recess cells-the agger nasi cell, four types of frontal cells, supraorbital ethmoid cells, suprabullar and frontal bullar cells. These cells, originally described by Van Alyea, have been revisited and defi ned over the last 15 years [1, 17, 24, 25]. Anatomically speaking, this is a narrow and confi ned area that is bordered medially by the anterior aspect of the middle turbinate, laterally by the lamina paprycea, anteriorly by the agger nasi region, and posteriorly by the skull base. The ease of endoscopic access to this small and intensely pneumatized area is in stark contrast to the facile external approach to the frontal sinus. Several tenets of functional frontal sinus surgery are particularly germane to dealing with dissection of the frontal recess. One is to remove the frontal recess cells completely, taking full advantage of the medial frontal sinus fl oor to enlarge the ostium and there by relieve potential sources for frontal recess obstruction. Enlarging the frontal sinus outfl ow tract below the ostium allows more effi cient mucociliary clearance from the frontal sinus and reduces the likelihood of frontal recess narrowing secondary to edema and scarring. Most importantly, however, is preservation of all frontal recess mucosa; this allows restoration of function without scarring. Fibrin clot does not adhere to intact mucosa. There is less likelihood of granulation tissue, fi brous scarring, and frontal sinus contracture. Any frontal recess mucosa inadvertently removed increases the likelihood of these problems. Anything which improves enlarging the drainage pathway while preserving the mucosa and mucociliary clearance is advantageous to patient outcomes. The operative technique for endoscopic frontal sinus and frontal recess surgery is detailed elsewhere in this book at great length. The purpose of this chapter is to detail the instrumentation that has advanced frontal sinus surgery and review the proper use of this instrumentation in light of these tenets of frontal sinus surgery.