15 The View in Support of Middle Turbinate Preservation and Medialization

The middle turbinate (MT), also known as the middle concha, has always been regarded as a key landmark in endoscopic sinus surgery (ESS). Its location, forming the medial boundary of the ostiomeatal complex, places it at the center of much of the effort to restore functional mucociliary clearance, particularly in the maxillary sinus. Determining the appropriate surgical approach to the MT has been a controversial topic for as long as intranasal surgery has been performed.1 Arguments in favor of MT resection have included easier endoscopic access, prevention of MT lateralization and synechia formation, increased maxillary antrostomy patency rates, as well as inflammatory changes to the MT itself.^2–6 However, the MT is a normal anatomic structure within the nasal cavity whose physiologic properties contribute to the overall milieu of the paranasal sinuses. Keeping this in mind, the debate on MT preservation or resection should revolve around whether this structure is, in fact, involved in the disease process itself. In the setting of a normal MT, we believe that the MT can and should be preserved in the majority of cases regarding maxillary sinus surgery. In this chapter, we aim to address the reasons for preservation of the MT as well as describe techniques to preserve this structure in various clinical situations.

Physiologic Reasons for Preservation

The MT plays a wide variety of physiologic roles within the nasal cavity. Some of the most accepted critical functions include the following:^1,7–10

• Directing and maintaining laminar airflow

• Humidifying and warming inspired air

• Particulate filtration to protect the maxillary and ethmoid cavities from the drying effects of inspired air, which may disrupt mucociliary clearance

• Participation in the nasal cycle

• Participation in olfaction

Given these functions, it would seem detrimental to routinely resect the MT in all cases of sinus surgery. The continued presence of unfiltered, cold, dry air flowing in a turbulent fashion may potentially lead to chronic mucosal dryness, squamous metaplasia, and even atrophy of the nasal mucosa. Although difficult to quantify, one study has tried to evaluate the changes in the nasal cavity environment following turbinate resection. In a selection of patients undergoing middle and inferior turbinate resection for inverted papilloma removal via a midfacial degloving approach, the authors found a significant decrease in nasopharyngeal humidity and temperature when compared with the nonoperated side.¹¹ Although this study involves a much more extensive procedure than partial middle turbinectomy alone, the results suggest possible problems that may be encountered with loss of turbinate tissue. Along this same spectrum is the risk of atrophic rhinitis. Similar to other authors, we have noticed certain patients who develop chronic drying and crusting within the maxillary sinus following MT sacrifice.^12,13 One final concern is the development of empty nose syndrome (ENS). Although this entity of paradoxical nasal obstruction in the presence of a widely patent nasal cavity is more commonly associated with inferior turbinate resection, there has been a recent case report of ENS associated with MT resection alone.¹⁴ Clearly then, although the full role of MT function remains incompletely understood, there is enough potential for unforeseen physiologic problems that may arise with unjustified MT sacrifice.

Anatomic Reasons for Preservation

Perhaps the most important reason for MT preservation is that the turbinate represents a consistent bony landmark in ESS. Arising from the third ethmoturbinal in the nasal cavity, the MT has three distinct planes and attachments. The anterior one-third of the MT sits in the parasagittal plane and attaches superiorly at the skull base at the lateral edge of the lamina cribrosa. The middle one-third lies in the coronal plane and turns laterally to insert into the lamina papyracea. And finally, the posterior one-third lies in the axial plane and attaches to both the lamina papyracea and the medial wall of the maxillary sinus.¹⁵ This three-dimensional attachment provides significant stability to the MT. In addition, the MT provides a bony structural boundary to many of paranasal sinus drainage pathways:

• The MT forms the medial boundary of the ostiomeatal complex (OMC), the functional drainage pathway of the frontal, maxillary, and anterior ethmoid sinuses

• The basal lamella of the MT provides the boundary between the anterior and posterior ethmoids

• The anterior, superior portion of the MT provides the medial boundary of the frontal recess (when the uncinate inserts into the lamina papyracea) and is a consistent landmark for the thinnest portion of the skull base at the lateral lamella of the cribriform plate

With such an important anatomic role in ESS, it is no surprise that most surgeons believe that MT sacrifice contributes to the disorientation and the surgical challenge of revision cases. In fact, in a study specifically analyzing the complications of ESS, Vleming et al has shown a significantly higher complication rate for revision ESS in the scenario of previous MT resection. These complications included injury to the lamina papyracea, orbital hematoma, and cerebrospinal fluid leakage.16

For those who argue that partial anterior, inferior MT resection avoids the loss of a bony landmark, the concern then becomes iatrogenic frontal sinus disease. The denuded mucosa of the partially resected and weakened MT is often seen adherent to the lateral nasal wall, which can obstruct the frontal sinus outflow tract (Fig. 15.1).^8,17 In a study of patients who were referred for revision ESS, Swanson et al found a statistically significant higher incidence of frontal sinusitis (75%) in patients who had previous MT resection during their initial procedure.¹⁸ With the risk of increased surgical complications as well as iatrogenic frontal sinusitis, we certainly feel that MT resection should not be routinely performed in all cases of ESS.

The Preservation versus Resection Debate

The historical background of MT preservation during ESS dates back to the original description of the surgery itself. Messerklinger (cited in Kennedy) advocated a meticulous mucosal sparing technique with all attempts made to preserve the MT.¹⁹ This is in contrast to the Wigand technique, which included a partial MT resection during routine ESS.²⁰ Undoubtedly, these two schools of thought surrounding the MT helped create the long running debate of MT preservation versus resection. The most commonly used reasons for resection include the following:^2–6

• Easier endoscopic access

• Prevention of MT lateralization and synechiae formation

• Higher maxillary antrostomy patency rates

• Inflammation and polypoid degeneration of the MT

With the exception of the last reason, we feel that routine MT resection is not justified and that current endoscopic technique and skill will overcome many of the concerns regarding MT preservation. Indeed, if the disease process involves the MT with significant inflammation or polypoid change, preservation of this structure may not be indicated. A recent study has shown that nasal polyposis recurrence rates were much lower in patients who had MT resection in conjunction with ESS.²¹ However, a normal MT in the setting of chronic rhinosinusitis deserves a different approach. The large variety of zero-degree and angled endoscopes that are available in 4-mm and 2.7-mm diameters provide the endoscopic surgeon numerous options to navigate and operate in the middle meatus region. With respect to the maxillary sinus, the advent of curved instrumentation in both adult and pediatric sizing allows for unhindered surgery with minimal mucosal trauma to the MT. Endoscopic access is clearly no longer a viable reason for routine MT resection.

Perhaps the most cited justification for MT sacrifice is the concern for postoperative lateralization of the MT, resulting in synechiae formation and occlusion of the maxillary and ethmoid sinuses.²² In fact, this is regarded to be the most common complication after ESS with rates as high as 43%.²³ In an effort to avoid this complication, the practice of MT resection was introduced. Although reports of high antrostomy rates (96.5%) and low synechiae rates (3%) have been reported with partial MT resection, these findings have been inconsistent in the medical literature.^2,5,24 Studies by Ramadan et al and Kinsella et al have shown no statistical difference in lateral synechiae formation between patients who had MT preservation versus resection.^25,26 An important point to mention, however, is that none of these studies were randomized controlled trials. In 1998, Stewart concluded that a properly conducted trial comparing MT resection and preservation would require a minimum of 420 patients per treatment group to detect a 5% difference in synechiae formation.³ To date, no such study has been performed and until that time, arguments in favor of either approach are largely influenced by surgeon bias. Given the fact that the reasons for routine MT sacrifice are not fully substantiated in the medical literature, we feel that a conservative approach to this normal, physiologic, and consistent landmark in the nasal cavity is both prudent and appropriate.

In 1999, Bolger et al described a technique of controlled synechia formation between the medial MT and nasal septum using a sickle knife blade. This procedure involved making four 0.5-cm cuts on each surface and placing Gel-film (Pfizer Pharmaceuticals, New York, NY) or Merocel (Medtronic, Mystic, CT) lateral to the turbinate to allow for medial synechia formation.27 This would then prevent the MT from lateralizing and the subsequent concerns of synechiae formation would be eliminated. In 2000, a modification of this technique was described by Friedman et al and is currently our preferred abrasion method. Instead of a sickle knife, the microdebrider was employed to form a limited and controlled synechia just posterior to the medial MT caudal edge and the adjacent nasal septum (see Video 15.1). Friedman et al used Telfa (Covidian, Mansfield, MA) lateral to the turbinate for 24 to 48 hours postsurgery and achieved a 92% medialization rate and 88% lateral synechiae-free rate in their series.¹⁷ In our institution, we prefer to use a Merocel pack placed in a latex-free glove finger as our standard middle meatal spacer, which is removed at one week. We feel that the glove finger prevents the mucosal abrasion, which can occur with Telfa or many of the middle meatal sponges.

Suturing Technique

Our preferred method of medializing the MT after ESS involves a technique that was described by Thorton in 1996. A 4–0 Vicryl (Ethicon, Somerville, NJ) suture is passed through the MT and nasal septum on both sides and then brought back through to the original side, in the manner of a horizontal mattress suture, and then tied down. In a series of 31 patients treated with this transseptal suturing technique, a 96.7% lateral synechiae-free rate was achieved.⁷ This method of preserving and medializing the MT has been employed with good success at other institutions.^28,29

At our institution, we prefer to use a purple-dyed 4–0 Vicryl suture on a tapered needle. We then relax the curve of the needle before loading it on the needle driver. The suturing technique is then performed much the same as was originally described by Thornton (see Video 15.2). This modification was described by Bradley F. Marple (via personal correspondence) and allows for easier manipulation of the needle within the nasal cavity itself. The senior author has employed this method for several years with excellent success of medializing the MT. The dyed suture also allows for easier identification in the postoperative period should the suture need to be removed after medialization has occurred.

Concerns about Preservation and Medialization

One of the concerns that arose after the advent of MT medialization techniques is the potential for obstruction of airflow to the olfactory mucosa in the superior nasal vestibule. To address this concern, Friedman et al measured subjective and objective olfactory function in patients following microdebrider-mediated synechiae formation. In a series of 50 patients, there was no subjective change in olfactory function after surgery and objective scores actually improved, although this did not reach statistical significance.³⁰ With these findings, the risk of airflow limitation to the olfactory fossa following MT medialization remains theoretical at best. Nonetheless, as further study continues in olfactory function, the advantage of the suturing technique is the ability to remove the suture in the postoperative period. Risks of olfactory dysfunction following MT resection do not employ the same reversibility.

Partial Resection and Preservation

Early proponents of MT resection cited anatomic variants such as a concha bullosa or a paradoxical MT as absolute indications to remove the MT.³ In the setting of a paradoxical MT, we certainly agree that partial MT resection may be necessary for definitive endoscopic access both during surgery and in the postoperative period. However, our preferred method of dealing with a concha bullosa is to resect only the lateral half of the turbinate using a combination of a sickle knife and endoscopic scissors (see Video 15.3). The remaining medial half of the MT can then be medialized with the abrasion or suturing technique, and a middle meatal spacer is placed to prevent lateral synechiae formation. This technique will thus allow for preservation of the medial half of the MT, which continues to serve as a consistent landmark in ESS.

Conclusion

In conclusion, the question of what constitutes the best approach to the middle turbinate in endoscopic sinus surgery has long been a controversial one. However, the development and success of MT medialization techniques allows for preservation of normal nasal structure and function without compromising mucociliary clearance. Given the availability of this option and the concern of MT resection causing frontal sinusitis, loss of normal physiologic balance and increased difficulty in revision cases, preservation and medialization of the middle turbinate appears to be the most prudent approach in the vast majority of endoscopic sinus surgery.