Discussion

Extranasal lateral rhinotomy or maxillary degloving with eth-moidectomy and medial maxillectomy are the gold standard operations for extensive inverting papilloma involving the ethmoid and maxillary sinuses. These procedures and the positive results reported in treating inverting papilloma were developed after years of inadequate intranasal and extranasal procedures. The only reason to change management philosophy depends on equivalent or improved management techniques. Endo-scopic diagnosis and surgery can improve our management of inverting papilloma. The use of endoscopic sinus surgery by experienced surgeons expands the management of inverting papilloma and allows for individualization of treatment. The management philosophy described below is safe, effective, and consistent with cutting-edge treatment of inverting papilloma.

The differential diagnosis of any unilateral nasal lesion should consider tumor first. The most common benign nasal tumor is inverting papilloma. Once endoscopic examination and/or CT scanning indicates that the tumor is limited to the nose or sinuses, or both, an endoscopic examination can often pinpoint the precise origin of the tumor, permitting more precise surgical planning. This possiblity was unavailable before endoscopy and is one of the reasons intranasal removal under direct vision failed. Tumors were usually detected only when large and bulky, requiring extensive surgery for removal. Also, the advent of endoscopic diagnosis with CT scanning for sinusitis has resulted in earlier diagnosis of sinusitis and sinus tumors—again, less surgery. Once the diagnosis is made, further radiologic evaluation to determine the extent of tumor may be necessary. Small localized tumors require only a CT scan. Large tumors affecting the nose and ethmoid sinus with evidence of sinusitis or opacification in contiguous sinuses such as the frontal, sphenoid, or maxillary sinus require an MRI with contrast to determine whether inverting papilloma is present in

those sinuses. Tumor extending into other sinuses in addition to the ethmoid requires specific planning for removal. Biopsy of unilateral nasal lesions can be performed in the clinic, provided that pre-biopsy radiologic evaluation (CT scanning) shows that the lesion is limited to the nose and sinuses and does not include the brain or skull base. For postoperative follow-up, the endoscope has a valuable role in diagnosis and treatment, which will be discussed later.

For primary tumors limited to the septum, middle, or superior turbinate or to the ethmoid sinus, endoscopic surgery is much more advantageous than direct headlight or microscope visualization and certainly superior to any type of external removal procedure. Carefully planned endoscopic procedures with complete control of inverting papilloma is the rule in most of these cases. Tumor origins can be nicely seen and tumor with safe margins removed. Ethmoidectomy for inverting papilloma should require not only tumor removal and ethmoidectomy, but also mucous membrane removal to lamina papyracea. In some instances, such as with bony erosion or involvement, the lamina papyracea requires removal. Removal of mucous membrane can be enhanced using a diamond drill burr or a microde-brider; removal of the lamina papyracea in the tumor area can be enhanced under endoscopic guidance. Inferior, middle, or superior turbinate inverting papilloma requires partial or total turbinectomy, depending on the extent of the tumor. Septal tumor necessitates mucosa removal to cartilage or bone for control. I have removed several localized tumors in this fashion, as have others, with good success.1-5'14

Removal of tumors in the ethmoid area with extent into the maxillary sinus requires an ethmoidectomy and a medial maxillectomy, which can be performed extranasally or endo-scopically, but this should be performed by experienced surgeons only4,14 (Fig. 5-1). The procedures for extranasal medial maxillectomy and ethmoidectomy have been nicely documented. The intranasal endoscopic procedures require eth-moidectomy with removal of mucosa, possible removal of

Endoscopic Medial Maxillectomy

Figure 5-1 Incisions for endoscopic medial maxillectomy. (The middle turbinate is retracted upward for the illustration.) (A) The dotted line represents the incision between antrostomies. The solid line represents the turbinate (inferior) incisions. (B) Completed endo-scopic medial maxillectomy.

lamina papyracea, and possible excision of middle turbinate, if affected with tumor. The medial maxillectomy is performed by removing the inferior turbinate just posterior to the nasolacrimal duct along with the medial maxillary sinus wall. This is done with medial and inferior meatus antrostomies, followed by bone cuts made with through-cut punch forceps through the anterior inferior turbinate, punch cuts vertically through the anterior fontanelle joining the antrostomies, punch cuts inferi-orly moving posteriorly to the posterior wall of the maxillary sinus, and a vertical cut between the medial and inferior antros-tomies posteriorly releasing the specimen. Disease extending into the maxillary sinus is removed down to bone, by means of angled telescopes and special instrumentation. Frozen-section biopsies can aid in achieving good tumor margins. Any tumor occurring laterally, anteriorly, or posterolaterally may require an anterior maxillary sinusotomy or a Caldwell-Luc to gain tumor control. In practice, the tumor is limited primarily to the medial wall, with most of the remaining thickened mucosa caused by associated sinusitis. Close follow-up management is necessary in all these patients. In my early experience with inverting papilloma in the maxillary sinus, I automatically converted to an external medial maxillectomy. As I gained endoscopic surgical experience and a better feel for inverting papilloma, I have been able to resect these tumors using endoscopic intranasal techniques only, as supported by the literature.1'14

Inverted papilloma occurs in rare cases in the sphenoid or frontal sinuses. This occurs from either extension from the ethmoid sinuses superiorly or posteriorly or direct involvement. A treatment dilemma occurs due to exposure and tumor removal. Should the frontal sinus be obliterated? Should all the mucosa be removed from the sphenoid given that the carotid artery may be dehiscent? Certainly, an osteoplastic flap may need consideration. Whether to obliterate or not is a judgment decision. Many surgeons have concern about placing fat into a sinus where tumor was present. I have concern about leaving tumor in the frontal recess, which is a difficult area to obliterate. Alternatives include a frontal floor sinusotomy (Lothrop procedure) through an osteoplastic flap, endoscopic frontal osteoplasty with trephination, external frontoethmoidectomy (Lynch procedure), or endoscopic frontal osteoplasty with sinusotomy (endoscopic Lothrop procedure). This is a rare occurrence and, therefore, it is difficult to recommend one procedure over another. Each case should be treated individually with the paramount consideration being removal of all tumor. For sphenoid inverting papilloma, a wide sphenoidotomy should be made, with removal of tumor mucosa guided by frozen section. Posterolateral dissection should be performed with great caution to avoid injury to the carotid artery. The carotid is dehiscent in up to 20% of patients, the optic nerve in 5%. Computerized stereotactic surgery may be very helpful in identifying key anatomy, to avoid complications, and in aiding tumor removal, particularly in the frontal or sphenoid sinuses.17

For patients failing primary inverting papilloma surgery, endoscopic diagnosis and surgery can help identify recurrence, salvage small recurrences, and help debride and reduce tumor bulk in large recurrences not amenable to further surgery; this approach can also aid in the diagnosis via biopsy showing benign inverted papilloma changing into or harboring squamous cell carcinoma. The endoscope can be a powerful weapon in all of these cases, as verified by my own personal experience. Recurrent disease in the maxillary sinus not treated initially by medial maxillectomy warrants consideration for this procedure. Endoscopic medial maxillectomy should only be considered by expert endo-scopic surgeons familiar with the technique and the principles of tumor surgery. The important point is that the goal is to achieve control of inverting papilloma at the first surgery. The best procedure to accomplish complete removal should be used.

Radiation therapy for uncontrolled inverting papilloma changing to carcinoma is an effective treatment. For an uncontrolled tumor not changing to carcinoma, radiation therapy has been used in a few cases for control of the tumor.18 I prefer close observation and timely biopsy as a better alternative for localized tumor, as there are concerns about the possibility that radiation therapy can induce inverting papilloma to change into carcinoma. Widespread uncontrolled tumor should be considered for radiation therapy.

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