Ethmoidectomy and antrostomy can be performed under local or general anesthesia depending on the patient's preference, the surgeon's experience, the health and age of the patient, and the severity of the sinus problem. In all cases, the mucous membrane of the nose is both anesthetized and vasoconstricted (i.e., to diminish the size of blood vessel) by application of drugs to the nose at the beginning of the actual surgery to minimize blood loss and to improve visualization of the operative field.
Surgery begins with a careful examination of the nose. Key landmarks are the three turbinates or chonchae (conchae = shell) arising from the lateral nasal wall, and the osteomeatal complex. The most anterior, or nearest to the front, structure within the osteomeatal complex is the uncinate process. This semilunar ridge of bone projects in front of the ostium of the maxillary sinus. Behind or posterior to the uncinate process, is a group of ethmoid cells known as the bulla ethmoidalis. The uncinate process must be completely and atraumatically removed to visualize the entire ethmoid sinus and maxillary ostium. In our experience, incomplete removal of the uncinate process is a significant factor in leading to revision surgery.
Endoscopic image showing identification of the uncinate process (up) and probing of the space immediately behind it, the ethmoid infundibulum, by a hook-like instrument known as an ostial seeker. The middle turbinate (mt) is an appendage of the ethmoid sinus and an important surgical landmark.
Removal of the uncinate process with a surgical debrider reveals the ostium of the maxillary sinus. This form of antrostomy permits inspection of the maxillary sinus and removal of polyps or other abnormal findings from within the sinus.
Following removal of the uncinate process, the maxillary ostium may be visualized. Over the past twenty years opinion has varied significantly as to how large one should make the ostium. As enlarging the maxillary ostium is synonymous with performing an antrostomy at this site, both terms describe the same procedure. We now favor minimal, or no, alternation of a normal appearing ostium.
Following the antrostomy, the maxillary is inspected and drained on infected mucous. If polyps, fungus or other abnormal findings are observed, these are removed. As a primary concept in minimally invasive or functional sinus surgery is the preservation of mucous membrane, which may return to a normal state following ventilation of the sinus, the membranes lining the sinus are conserved.
This is a significant departure from early treatment of maxillary sinusitis by more aggressive procedures, such as Caldwell Luc, which included removal of the entire mucous membrane lining of the sinus. Such a transition in surgical thinking is interesting in that as early as 1916 when the American anatomist, J. Parsons Schaeffer stated that "maxillary sinus is often the cesspool for infectious material from the sinus frontalis and certain of the anterior group of cellulae ethmoidales".
This implies that maxillary sinusitis is the consequence of drainage of infected secretions from the other sinuses. Therefore, surgical treatment should focus on the other sinuses and alterations to the maxillary sinus should be minimal.
A surgical curette is shown removing the cells of the posterior ethmoid sinus. The boundaries of the ethmoid sinus are the lamina papyracea (lp), the middle turbinate (mt) and the floor of the anterior cranial fossa or skull base. The lamina papyracea or orbital plate is a thin vertical plate of bone which separates the ethmoid sinus from the orbit. In sinus surgery, each of these boundaries should be visualized and with the possible exception of the middle turbinate, preserved intact.
Following antrostomy, the anterior ethmoid cells are entered with surgical forceps, curette or debrider. The actual technique of ethmoidectomy has evolved to combine two approaches. One approach begins in the back of the nose and consists of resection of the middle turbinate to gain exposure to the posterior ethmoid cells and face of the sphenoid sinus, cannulation of the sphenoid ostium or removal of the anterior wall of the sphenoid sinus, and total ethmoidectomy.
This classic technique was adapted to the endoscope by Wigand. The other approach was developed by Messerklinger and Stammberger to utilize their studies of the physiology of the sinuses to apply the optical telescope to modify the anterior ethmoidectomy of Halle. This procedure has the advantage of selectively limiting surgery to the pathologic sinuses. In performing a front-to-back procedure, surgery begins with anterior ethmoidectomy and is extended into the back or posterior sinuses depending on the site of disease.
The virtues of both approaches are now used by many surgeons and are described by Schaefer as the "combined approach".
Sagittal, or midline cadaver section through the ethmoid sinus. On the right is the sphenoid sinus (SS) and on the left is the external nose. The area through which the frontal sinus drains into the nose is known as the frontal recess (FR). This section illustrates the removal the inferior or lower ethmoid cells which are encompassed by the dotted line as the procedure progresses from the front to back of the nose.
The same cadaver section illustrates the back to front (see arrow) removal of the upper ethmoid cells which are outlined by a dotted line.
Halle, M. 1915 Die intranasalen operationen bei eitrigen erkrankungen der nebenhohlen der nase. Arch. Laryngol. Rhinol., 29:73-112.
Kennedy, D. and Senior, B.A. 1997 Endoscopic sinus surgery: A review. Otolaryngol. Clin. North Am., 30:313-330.
Messerklinger, W. 1985 Endosckopiche diagnose und chirugie der rezidivierenden sinusitis. In: Krajina, Z., ed. Advances in Nose and Sinus Surgery. Zagreb, Yugoslavia: Zagreb University.
Schaefer, S.D. 1998 An anatomic approach to endoscopic intranasal ethmoidectomy. Laryngoscope, 108:1628-1634.
Schaeffer, J.P. 1916 The genesis, development, and adult anatomy of the nasofrontal region in man. Am. J. Anat. 20:125-143.
Stammberger, H. 1986 Endoscopic endonasal surgery-concepts in the treatment of recurring rhinosinusitis: Part II. Surgical technique. Otolaryngol. Head Neck Surg., 94:147-156.
Wigand, M.E., Steiner, W. and Jaumann, M.P. 1978 Endonasal sinus surgery with endoscopical control: From radical operation to rehabilitation of the mucosa. Endoscopy, 10:255-260.