Ethmoidectomy is defined as the excision of the cells of the ethmoid sinus or ethmoid bone. This procedure was originally described using an external approach through the skin between the external nose and the medial canthus (opening to the tear duct). This evolved into an intranasal (through the nose) procedure using either a headlight, operating microscope or an optical endoscope. A third approach is to enter the ethmoid sinus through the maxillary sinus. No matter the approach, the ethmoid sinus is the key or essential element in the surgical treatment of sinusitis. The ethmoid sinus is important because all of the other sinuses drain either through or adjacent to this sinus. Disease within or extending beyond the ethmoid, can obstruct the ability of air to enter the affected sinus and for mucous to drain.
The computed tomographic (CT) scan illustrates the proximity of the ethmoid sinus to the other sinuses and adjacent important structures. This scan also shows a defect (white arrow) in the roof of the right ethmoid sinus, from which cerebral spinal fluid is draining into the nose.
Antrostomy is broadly defined as making an opening into the maxillary sinus for the purpose of drainage. This word is derived from epipinym for the maxillary sinus which is the antrum of Highmore, named after the anatomist Nathanial Highmore whose 1651 treatise Corporis Humani Disquisitio Anatomica describes and illustrates this sinus, and the term for an opening to permanently drain an organ, ostomy.
Original illustration of Nathanial Highmore showing the maxillary sinus, c. 1651 (courtesy of the New York Academy of Medicine Library).
Prior to the advent of endoscopes that permitted precise visualization of opening or ostium of the maxillary sinus into the nose, antrostomy was typically performed beneath the inferior turbinate. This site is further from the eye, and was easier to visualize at surgery using a headlight or operating microscope than the actual ostium of the maxillary sinus. However, all sinuses are lined by mucous membrane which transports secretions, known as mucociliary flow, to the opening of the sinus into the nose.
Further, surgical treatment of maxillary sinusitis is both depended on re-establishing functional drainage and removing the source of re-infection of this sinus. That is, disease within the ethmoid sinus. For this reason, "older operations" such as Caldwell Luc have evolved from the mainstay procedure to treat maxillary sinusitis to primarily a procedure to access this sinus when endoscopic approaches are inadequate or inappropriate.