Andrew H. Murr, MD
Although use of the endoscope (a small, rigid telescope) and camera during sinus surgery is now the norm for the vast majority of otolaryngologists, the technology is relatively new in the broad view of how surgical technology has progressed. Over three decades ago, Walter Messerklinger in Graz, Austria was primarily responsible for developing and introducing the glass rod endoscopic systems that are now standard in most operating room and clinic settings in the U.S. and many parts of the world. It is arguable that the major advance to clinical practice that the endoscope brought was not really a major change in surgery, rather, it allowed a major change in what could be seen during surgery. Prior to the introduction of the endoscope, for nearly 100 years, visualization was obtained using lights and incisions. The incisions were sometimes hidden under the lip or in creases of the facial skin or behind the hairline. These techniques are referred to as external sinus surgery techniques.
External sinus surgery techniques are rarely a primary choice anymore by most surgeons. However, neither are the techniques completely obsolete or contraindicated for certain situations. The benefit of direct visualization afforded by external approaches is supported by their longevity and in the fact that risks, complications, and alternatives are extremely well understood because of the well defined experience that surgeons have had with them. It is somewhat ironic that because the techniques are rarely required and rarely used, that many practitioners have relatively limited experience with how the techniques are accomplished. Today, external sinus surgery approaches are more frequently used as an adjunct to endoscopic techniques or when special circumstances exist such as massive facial trauma, acute infection, or rare tumors occur.
The inventory of external sinus procedures includes Caldwell-Luc surgery to approach the maxillary sinus (an incision beneath the lip in the oral cavity), external ethmoidectomy surgery through a trans-facial Lynch incision or Weber-Ferguson incision (incisions going across the face), the frontal sinus trephine operation through a medial brow incision (an incision beneath the eyebrow), and the frontal sinus osteoplastic flap approach which is usually accomplished through a coronal incision behind the hairline (an incision across the top of the head). Finally, a combination approach to the ethmoid and frontal sinus can also be accomplished through a Lynch incision, with or without an attempt to re-mucosalize (or re-line) the frontal sinus drainage tract.
Caldwell-Luc Approach: the Caldwell-Luc approach was the mainstay of sinus surgery from approximately 1900 until about 1990. It is accomplished through an incision under the upper lip at the gum line. Through this incision, the cheek can be retracted, the maxillary division of the trigeminal nerve can be identified and preserved, and the anterior wall of the maxillary sinus can be removed to allow full access to the maxillary sinus. This general approach to the anterior wall of the maxilla is still used routinely in trauma reconstructive surgery because it leaves a scar that is not visible on the skin and because it allows reconstruction plates to be placed to fix fractures. In sinus surgery, however, this approach is not typically required because excellent access to the maxillary sinus can now be achieved through the nose, with the creation of a large opening in the lateral nasal wall called a middle meatal antrostomy. Creation of large antrostomies, however, is now a somewhat controversial topic amongst rhinologists. A competing technology to the creation of large surgical drainage openings was popularized by Ruben Setliff and is referred to as “small hole” or “small fenestra” surgery. Also, the development of balloon technologies to expand natural sinus drainage tracts has been recently refined which have a theoretical advantage of requiring less sinus surgical disruption to achieve improvement of chronic sinusitis symptoms. One of the new balloon technologies actually uses a Caldwell-Luc approach to place the balloon through a small incision in the gum under the upper lip much as described in the original operation. The advantage of the Caldwell-Luc approach in this setting is that it allows a more direct approach to the natural ostium of the maxillary sinus for balloon placement using endoscopic instrumentation and causes less disruption of the ethmoid sinus anatomy.
External ethmoidectomy: external ethmoidectomy is accomplished through a small skin incision between the nasal bridge and the eye. The scar from the incision can be extremely well hidden using various plastic surgery techniques. In general, this technique has been fully replaced by endoscopic trans-nasal techniques that do not require an incision on the facial skin. However, this technique can still be useful in some special circumstances. Two examples include acute bacterial sinusitis which causes an abscess in the eye and requires surgical drainage and severe arterial nose bleeds which require surgical ligation of the anterior ethmoid artery. To be sure, both of these stated operations can be accomplished endoscopically, however, endoscopic operations in these circumstances often require special equipment like image guidance, trained nursing crews and technicians, special surgical tools including customized hand instruments and cautery, and microdebriders. All of these things are not always available to every surgeon. Sometimes, these types of procedures are also urgent or emergent. The external ethmoidectomy approach is sometimes the safest and most direct, quickest method to accomplish surgery in some conditions. Finally, the external ethmoidectomy is still sometimes used as an approach by skull base surgeons when addressing problems like tumors requiring surgery or cerebrospinal fluid leak repair, although this is rarely needed.
Frontal sinus trephine: this operation is still in somewhat common use in specific circumstances. It is an excellent adjunct to endoscopic frontal sinus surgery such as the Endoscopic Lothrop operation (Draf III). In fact, a frontal sinus trephine is also a reasonable adjunct to less extensive frontal sinus operations as well. The approach is accomplished through a 1 cm incision just under the medial eyebrow. It should heal nicely. The trephine allows endoscopes or other instruments to be placed directly into the frontal sinus to allow secure endoscopic approaches to the frontal drainage tract from the ethmoid sinus via the nasal route. In addition, the frontal sinus trephine operation is still an option in acute frontal sinusitis especially when an abscess has occurred near the eye or brain.
Frontal sinus osteoplastic flap: this operation popularized by Bergara and then Montgomery in the 1950’s and 1960’s is accomplished through an incision through the scalp or sometimes the forehead. Direct access to the frontal sinus is afforded. By creating a template from a 6 foot perfect Caldwell x-ray film, the surgeon can outline the anterior wall of the frontal sinus and cut through the bone lifting off the anterior outer table of the sinus and producing wide exposure to the walls and drainage tracts of the sinus. Now that CT guided navigation is very common, this navigation can also be used to identify where these cuts should be made. Surgical instruments can be brought directly to work on various problems like tumors or fractures. This approach is still used in severe trauma where multiple bone fragments from different fractures have affected the forehead. In these circumstances, the sinus can be filled with a fat graft or other tissue graft or other material to block it off. In circumstances where the posterior table of the frontal sinus is severely fractured, the brain can be allowed to expand into the sinus to in effect block off the space. This is called cranialization. In instances where endoscopic frontal sinus surgery has failed due to scarring of the frontal sinus drainage tract, sometimes osteoplastic frontal sinus obliteration will still be recommended. Despite the extensive nature of the operation, the cosmetic outcome is often quite good because the surgical scars can be hidden behind the hairline. As endoscopic sinus surgery techniques become more and more refined and as an appreciation of the need to preserve sinus anatomy using meticulous surgical technique becomes more ingrained, the need to correct scarring complications from endoscopic ethmoid and frontal sinus surgery will mean that this osteoplastic obliteration operation is required less for issues pertaining to chronic sinus infection. The technique, however, will still likely have applicability for trauma situations and for some tumor approaches.
The risks, complications and alternatives of external sinus surgery are similar to the risks and complications of endoscopic sinus surgery. Risks include bleeding, infection, and failure or recurrence of the problem. Injury to the brain or eye can occur just like during endoscopic surgery. Specifically, cerebrospinal fluid leak, eye muscle damage, or bleeding into the eye which can cause blindness are remote possibilities. Diplopia or double vision may be a consequence of surgery approaching the orbit or eye socket. Of course, because these external approaches are accomplished via external incisions, visible scars can result. Also, facial numbness from cutting or stretching of sensory nerves can rarely occur. Facial asymmetry may result from some of these approaches but is unusual and depends to a great degree on the extent of the required surgery. Specific to the Caldwell-Luc is the low risk of creating a persistent opening between the mouth and sinus called an oral-antral fistula which could require revision surgery, or possibly damage to a tooth. Benefits pertain to the specific conditions for which the surgery is being planned.
Follow-up visits for these procedures are similar to follow-up for most sinus surgery except often for frontal sinus osteoplastic flap surgery and for external ethmoidectomy surgery, overnight or several nights of hospitalization may be recommended. Typically, any sutures that require removal would be removed at about 7 to 10 days. The acute phase of recovery is usually complete after 3-4 weeks, and long term follow-up over months to years would depend on the specific reason for the surgery. Surgery for tumors would usually require more extensive follow-up than surgery for the consequences of a one time acute bacterial infection that had resolved after treatment.
External sinus procedures are still sometimes used even with our modern endoscopic surgical techniques. Although these techniques are classical and were described long ago, they can sometimes be used adjunctively as an elegant solution to difficult problems or to allow a more secure and complete minimally invasive endoscopic operation.
External operations are currently a mainstay of trauma reconstruction. They are a reasonable option in surgery for complications of acute bacterial sinusitis, severe arterial nose bleeds, and some types of tumor surgery.