TORONTO—Techniques in functional endoscopic sinus surgery (FESS) have come a long way since their inception, and there are new ways of working with patients. Experts discussed advances in FESS during a panel session at the annual AAO–HNS conference here.
Explore This IssueDecember 2006
In terms of technology, “the evolution of sinus imagery really has mirrored our sinus surgery evolution,” said Raj Sindwani, MD, session moderator and Assistant Professor at St. Louis University.
Today, “we have detailed registration processes, great reconstructions, and multimodel navigation capabilities. These are permitting us to really push the envelope as we chase disease processes into smaller recesses of the head,” he said.
For presurgical examinations, CT is the modality of choice. It shows great detail, especially of the bony ethmoid partitions, and simulates the endoscopic appearance of the sinus cavities. The advantages of multichannel CTs are speed, submillimeter scanning, and less exposure to radiation. “It’s quicker, and you get less motion artifact,” Dr. Sindwani said.
CT is used as a diagnostic tool, but is also valuable for preoperative planning. “Preoperative planning begins in the clinic when you’re looking at the CT for the first time,” he said. It should be followed up with operative planning on the computer workstation of the image guidance system in the OR, he said.
Generally, any systematic approach is useful with CT evaluation, he said. Dr. Sindwani starts with the coronals, looking anterior to posterior, then looks at the axial. With specific frontal sinus issues, he wants to see the sagittals.
There are several normal anatomic variants to watch for that may not need surgery. Among these are a middle turbinate that can be paraxodically bent, or is pneumatized (concha bullosa). There can be ethmoid variants, haller cells, and giant ethmoid bullae that can be confusing. The agger nasi cell can be one of the most difficult to conceptualize, yet is vital in frontal sinus surgery—it shows up best in a sagittal CT cut.
“If there’s any disease associated with them, we would address them at the time of surgery,” Dr. Sindwani said. If there is no associated disease (such as concha bullosa with a clear ipsilateral maxillary sinus and ethmoid cells), then the concha bullosa is considered an anatomic variant and is left alone.
MRI, which is underutilized by otolaryngologists, can be used in a complementary study. It can reveal key details of sinsonasal masses, including the nature of a mass, its boundaries, extension, and levels of invasion. It can also elucidate different types of inflammatory sinus disease.
Dr. Sindwani encouraged audience members to use navigation devices for preoperative planning as well as in surgery. In addition to providing accurate and reliable localization during surgery, the next generation of more compact image-guided surgery platforms offer a user-friendly interface and quick patient data transfer optimizing surgeon workflow during the preoperative planning session, which can easily be performed in almost any operating room environment. Imaging and navigation data sets are transferable and may be fused. The otolaryngologist can take preoperative CT and MRI scans and download both data sets into the image guidance system, which fuses them together so “you can navigate during the procedure using only CT, CT and MRI superimposed, or only MRI,” he said.
Maxillary Sinus Issues
Eric Holbrook, MD, Assistant Professor at Harvard Medical School, discussed the maxillary sinus and approaches to it, along with pitfalls that can lead to failures.
It is important to identify the uncinate and the natural ostium. “Really take your time to find it—it can save you a lot of headaches and potential complications,” he said.
Failures can be caused by being too aggressive around the middle turbinate and the lateral aspect of it can be traumatized causing scar formation. Too aggressive an antrostomy can be problematic too.
When performing an antrostomy, the uncinate needs to be addressed and the natural ostium identified. An incomplete uncinectomy won’t solve an obstructive problem, and recurrence can occur. A posterior antrostomy that doesn’t address the natural outflow can lead to persistent pathology.
Take time to observe the natural osteum, although it can be difficult to see in some cases. It should be behind the lower third of the uncinate and can be identified with the use of a 30-degree endoscope and gentle probing with a ball-probe sinus seeker.
“When you figure out where the natural osteum is and determine that enlargement is necessary, use a through-cut forceps to widen it in a posterior and inferior direction,” Dr. Holbrook said. Cutting instruments avoid tearing and stripping the mucosa.
Preventing Ethmoidectomy Complications
Joseph Han, MD, Assistant Professor at the University of Virginia, provided tips on avoiding ethmoidectomy complications. Key points are to know the endoscopic ethmoid anatomy, understand how the anatomy may appear altered through an endoscope, and be aware of different anatomic variations.
When performing FESS, Dr. Han breaks down his approach into “segmental sinus surgery”—maxillary antrostomy, anterior ethmoidectomy, posterior ethmoidectomy, sphenoidotomy, skull base dissection, and frontal sinusotomy. “I define boundaries. [For instance], before I do a posterior ethmoidectomy, I would make sure I had the boundaries of the anterior ethmoid cavity dissected,” he said. Use CT scans, and correlate them to the endoscopic anatomy.
If FESS is to be performed standing up, Dr. Han suggested putting patients in a semireclined “beach chair” position so the endoscope, once in the nasal cavity, is parallel to the patient’s skull base.
If a patient is supine, “the normal tendency is to work toward the skull base. It’s natural for us in this position, [when the patient is lying down] to look up.…Look back, so you go toward the sphenoid sinus rather than looking up into the skull base,” Dr. Han said.
In addition, endoscopic views provide only a partial view of the surgical field. Also, the view can be altered by anatomic variations. For instance, with a deviated septum the otolaryngologist tries to keep the endoscopic view in the center of the surgical field between the septum and the lateral nasal wall. The endoscope will be pushed toward the orbit. The surgeon has to “constantly refocus and examine where you are in the big surgical field,” Dr. Han said.
Other tips include having good lighting for the endoscope, minimizing trauma and bleeding so the tissue planes can be found, and being meticulous and specific in how instruments are used. Nasal constrictor medication helps too.
Sphenoid Sinus Surgery
Peter Batra, MD, Assistant Professor of Surgery at the Cleveland Clinic, addressed surgery of the sphenoid sinus. Knowing the anatomy is vital. The superior turbinate is an important landmark, which leads to the sphenoid ostium.
The sphenoid sinus has “an intimate relationship to the internal carotid artery, the pituitary gland, and multiple cranial nerves including optic nerve, V2, and the vidian nerves. If we go into the sphenoid sinus, we have to be aware of these structures,” he said.
Don’t assume there are bony coverings over critical structures such as the optic nerve. CT studies of cadavers have shown “about a fifth of the time there are not any bony coverings,” he said.
As for the surgical approach, either transnasal or transethmoid sphenoidotomy may be utilized, depending on the pathology. Generally, the transnasal is the simplest and most direct, with indications including isolated sphenoid inflammatory disease, endoscopic pituitary disease, and central sphenoclival pathology.
The transethmoid route is appropriate in cases of diffuse inflammatory sinonasal disease and benign and malignant sinonasal neoplasms; the transmaxillary approach is used for lateral sphenoid CSF leaks.
No matter which approach is used, it’s vital to have “a careful review of the preoperative imaging prior to the execution of surgery,” and know where the critical structures are, Dr. Batra said.
Frontal Sinus Procedures
Alexander G. Chiu, MD, Assistant Professor of Rhinology at the University of Pennsylvania, addressed surgery of the frontal sinus.
“The workhorse procedure for a basic frontal sinus case is an endoscopic Draf IIA,” he said. The keys are to know the anatomy, identify the cells that block the frontal recess, find natural drainage pathways around the cells, and remove the cells.
In his own practice, Dr. Chiu defines the borders, and plans on how to make the frontal recess as big as possible. “There’s no such thing as small hole frontal sinusotomy. You want to make it as big as possible while sparing the mucosa around the recess. It will scar down in the postoperative period,” he said.
The first step in frontal surgery is to identify the skull base, and the safest to identify it is posteriorly in the sphenoid sinus or posterior ethmoid.
Approach the frontal recess from a posterior-to-anterior direction. Locate the anterior ethmoid artery, which will appear in preoperative CT scans. As you move anteriorly, be prepared to identify a supraorbital ethmoid cell and remove the bony wall between this cell and the frontal recess to maximally enlarge the sinusotomy.
Moving anteriorly, don’t forget about the agger nasi and the uncinate process, “which is by far the most common cause for revision surgery,” Dr. Chiu said. Finally, he said, dissect out the frontal recess cells and visualize the top of the frontal sinus to confirm that “you have the true recess dissected out and are not looking at a cap of an agger nasi or frontal recess cell.”
Rakesh K. Chandra, MD, Clinical Assistant Professor at the University of Tennessee in Memphis, discussed postoperative care after endoscopic surgery.
Post-op care begins in the operating room after the dissection is complete. “It has to do with the quality of mucosal preservation as well as the use of any packing. Medical management is also very important,” he said.
The goals of debridement have to be considered in light of the fact that mucociliary clearance after surgery can take up to six weeks to recover.
“During this six-week period it is important to suction your dependent sinuses, culture any purulence, remove crusted clots, lysis of adhesions, resect foci of recurrent polyp or change, remove osteitic bone, and then address middle turbinate lateralization, and most importantly ensure patency in the frontal recess,” he said.
Dr. Chandra said he performs debridement at follow-up visits, usually at either weeks one, two, and four or weeks one, three, and five post-op. “The appearance of the cavity is more important than the patient’s symptoms,” he said.
As for planning pre-op medical therapy, patients should be categorized into one of three presentations: nonhyperplastic chronic sinusitis, hyperplastic chronic sinusitis, or classic allergic frontal sinusitis, and medical therapy geared accordingly. He noted that sinus flora tend to change after FESS.
Patients with polyps are often pretreated with prednisone, starting three days before surgery. Patients with classic allergic frontal sinusitis may need to start earlier.
Saline irrigation is important post-op, with the mechanical cleansing effect being key. Commercial products and home recipes all seem effective. There is debate about the best delivery vehicle “but as long as it’s positive pressure I think it works well,” he said.
Topical detergents, antifungals, and steroid irrigation all have roles to play in pre-op care, depending on the patient. Not all patients are compliant with irrigations, so consider nasal sprays. The disadvantage with sprays is they don’t provide a positive pressure mechanical clean-out effect.
©2006 The Triological Society