There remains a continued debate regarding the extent of endoscopic sinus surgery (ESS) required for patients with chronic rhinosinusitis (CRS). By examining anatomic, etiologic, and postoperative factors that may lead to recalcitrant CRS, this article aims to highlight some of the reasons for performing maximal techniques in ESS. This concept is further expanded in various surgical maneuvers including wide maxillary antrostomy, extended frontal sinus procedures, and intraoperative computed tomography–guided ESS.
Since its introduction into North America in the mid-1980s, techniques of endoscopic sinus surgery (ESS) have continued to evolve as further understanding is gained in the pathogenesis of chronic rhinosinusitis (CRS). Although the fundamental concepts of improving sinus ventilation and mucociliary function remain paramount in treatment efforts, there remains a continued debate regarding the extent of ESS required for patients. Various studies have shown that ESS achieves symptomatic success rates ranging from 74% to 97.5%. This, however, leaves upward of 26% of patients with persistent disease despite surgical treatment, with approximately 10% of patients requiring revision surgery within 3 years. Patient symptoms recalcitrant to primary surgery is often secondary to persistent mucosal disease, such as polypoid edema, biofilm colonization, and the pooling of thick, allergic mucin. To minimize these failures as well as to offer a surgical alternative to the treatment of CRS recalcitrant to primary surgery, this article aims to highlight some of the reasons for performing maximal techniques in ESS. In addition, the authors hope to expand this concept in various surgical maneuvers that may help in the long-term management of patients with CRS.
Reasons for maximal technique
Although this article emphasizes the utility of maximal techniques in ESS, it should be mentioned that normal nasal physiology and mucociliary clearance mechanisms are not neglected. Instead, the indications for maximal surgery reflect the reasons why patients fail primary ESS and ultimately have recalcitrant CRS. These reasons can be divided in 3 main categories: anatomic, etiologic, and postoperative factors.
Anatomic factors
There have been numerous studies that have evaluated anatomic findings in patients who require revision surgery. Musy and Kountakis evaluated a prospective series of patients undergoing revision ESS and reported that the most common postsurgical alterations include lateralization of the middle turbinate (78%), incomplete anterior ethmoidectomy (64%), scarred frontal recess (50%), retained agger nasi cell (49%), incomplete posterior ethmoidectomy (41%), middle meatal antrostomy stenosis (39%), and a retained uncinate process (37%). These findings are further substantiated in a case series by Chiu and Vaughan, which demonstrated that patients requiring revision frontal sinus surgery often have residual agger nasi cell or ethmoidal bulla remnants, retained uncinate process, lateralized middle turbinate, and unopened frontal recess cells. With the exception of a destabilized middle turbinate, all these anatomic findings are suggestive of incomplete surgery that has led to persistent sinus obstruction and surgical failure. Hence, one of the basic tenets of maximal technique is to ensure complete removal of all obstructing bony partitions and to maximally enlarge diseased sinus ostia to help reduce this risk of scarring and stenosis.
Anatomic factors
There have been numerous studies that have evaluated anatomic findings in patients who require revision surgery. Musy and Kountakis evaluated a prospective series of patients undergoing revision ESS and reported that the most common postsurgical alterations include lateralization of the middle turbinate (78%), incomplete anterior ethmoidectomy (64%), scarred frontal recess (50%), retained agger nasi cell (49%), incomplete posterior ethmoidectomy (41%), middle meatal antrostomy stenosis (39%), and a retained uncinate process (37%). These findings are further substantiated in a case series by Chiu and Vaughan, which demonstrated that patients requiring revision frontal sinus surgery often have residual agger nasi cell or ethmoidal bulla remnants, retained uncinate process, lateralized middle turbinate, and unopened frontal recess cells. With the exception of a destabilized middle turbinate, all these anatomic findings are suggestive of incomplete surgery that has led to persistent sinus obstruction and surgical failure. Hence, one of the basic tenets of maximal technique is to ensure complete removal of all obstructing bony partitions and to maximally enlarge diseased sinus ostia to help reduce this risk of scarring and stenosis.
Etiologic factors
Maximal techniques in ESS are also supported by an increased understanding of the pathogenesis of recalcitrant CRS. Kennedy and colleagues have previously described histologic and endoscopic evidence of underlying bony inflammation in patients with persistent mucosal disease. These features can be appreciated on computed tomography (CT) scans where there is increased bone density or thickening in the paranasal sinuses. Both animal and clinical experiments have shown increased bone remodeling in these regions. Although bacteria have never been demonstrated within the bone itself, these areas of bony osteitis may be a significant source of persistent mucosal inflammation. Although areas of bony thickening along the skull base and medial orbital wall should be left intact, one should attempt to remove all osteitic bony partitions in the ethmoid labyrinth or in the frontal recess to help prevent disease recurrence. Minimal techniques aimed at only opening transition spaces do not address this potential contributing factor in recalcitrant CRS.
More recently, there have been numerous studies that have implicated biofilms as a potential etiologic factor in CRS. Biofilms are a “structured community of bacterial cells enclosed in a self-produced polymeric matrix.” One of their unique and challenging characteristics is their adherent nature on sinus mucosa and their ability to resist systemic antibiotics and evade host defenses. Consequently, new strategies including delivery of topical antibiotics to achieve high local minimum inhibitory concentrations as well as surfactants to increase mucociliary clearance have been employed, with promising results both in in vitro and limited clinical studies. Most of these medications are delivered to the nasal cavity as an irrigation wash with topical saline. However, the effectiveness of these treatments is based on the premise that irrigations efficiently reach and coat the paranasal sinuses. This concept has recently been investigated by a cadaver study performed by Harvey and colleagues. In this experiment, the effectiveness of sinus irrigation was studied in the nonoperated state and also following complete ESS (including uncinectomy, maxillary antrostomy, total ethmoidectomy, sphenoidotomy, and wide frontal sinusotomy). Using 3 different delivery devices filled with Gastroview contrast (pressured spray, neti pot, and squeeze bottle), the investigators found that there was limited penetration into the paranasal sinuses in the nonoperated state. However, following ESS there was a statistically significant improvement in total sinus distribution for all delivery devices, with the frontal and sphenoid sinus most affected by surgery. Extrapolating these results, these findings clearly demonstrate that a major advantage of maximal ESS techniques would be an improved delivery of topical medications. Whether or not biofilms continue to be implicated in CRS, complete ESS with wide sinus openings will have the advantage of facilitating optimum local therapy including anti-inflammatories and antibiotics. In addition, the role of mechanical debridement with high-volume saline irrigations should not be underestimated.
Postoperative factors
One final consideration when deciding on the extent of sinus surgery should be the ability to provide adequate postoperative monitoring and care. It is during this crucial period that the sinus surgeon can continue to endoscopically monitor and adjust the medical therapy required for resolution of disease. Important findings may include areas of mucosal swelling, purulent discharge, and the presence of allergic mucin ( Fig. 1 ). Without adequate openings, endoscopic visualization of sinus cavities and in-office debridement can be cumbersome and often impossible despite topical anesthesia. Similarly, widely opened sinuses may decrease the need for repeat imaging, as direct endoscopic examinations can provide objective evidence for recurrent or persistent infections. Ultimately, maximum technique in ESS is a concept of providing the most complete surgery required for long-term disease resolution. The following sections describe individual “maximum” techniques that may be a useful adjunct in the treatment of CRS.
Wide maxillary antrostomy technique
Chronic maxillary sinusitis was one of the first diseases to be effectively addressed and treated by endoscopic surgical technique. Rather than the Caldwell-Luc procedure whereby the diseased sinus mucosa is stripped, endoscopic middle meatal antrostomy aims to restore mucociliary clearance at the natural ostium while preserving the sinus mucosa. For the majority of their patients with chronic maxillary disease requiring ESS, the authors believe that a wide maxillary antrostomy technique is often appropriate. This procedure involves the following steps:
- 1.
Complete uncinectomy
- 2.
Visualizing the natural sinus ostium (usually with an angled 30° endoscope)
- 3.
Enlarging the ostium posteriorly to include the posterior fontanelle and any accessory ostia
- 4.
Enlarging the ostium inferiorly to the insertion of the inferior turbinate
- 5.
Removal of any obstructing infraorbital (Haller) cells
- 6.
If the maxillary sinus bulges medially into the nasal airway, the antrostomy should be extended posteriorly to the pterygoid plate to prevent deflection of airflow into the maxillary sinus.
There has been much debate recently over the optimum size of the maxillary antrostomy. In fact, some surgeons only advocate an uncinectomy alone as they believe its proximity to the natural ostium is the limiting factor in maxillary sinus disease. The authors certainly acknowledge that mild mucosal disease may require minimal manipulation of the sinus ostia. In fact, this level of disease may respond to medical therapy alone. However, patients requiring surgical intervention often have edematous mucosa with polyps, purulent discharge, allergic mucin or, possibly, biofilms. Without an adequate antrostomy, endoscopic inspection and clearance of disease may be limited. Perhaps most importantly, topical penetration into the maxillary sinus is significantly improved following antrostomy, regardless of the delivery device used, This single factor may underscore the need for an adequate maxillary sinus opening, especially as new topical therapies emerge for the treatment of CRS.
The primary concern over a large antrostomy often centers on the role of nitric oxide (NO) in the maxillary sinus. NO is known to be produced in the paranasal sinuses, and is thought to play an important role in ciliary function as well as providing antibacterial, antiviral, and antifungal properties. The fear is that a large antrostomy would lead to decreased levels of NO in the maxillary sinus resulting in ciliary stasis and persistent infections. Although there has been a study that has shown decreased levels of NO in the maxillary sinus with an ostium greater than 5 × 5 mm, investigators also note there is no scientific evidence linking low NO levels and recurrent maxillary sinusitis. In one clinical study, Albu and Tomescu attempted to evaluate the size of middle meatal antrostomies in the treatment of chronic maxillary disease. These investigators found no symptomatic difference in treatment outcomes between patients who had antrostomy sizes of 16 mm versus 6 mm. However, there were no data showing that subjects were adequately matched preoperatively for disease severity based on either objective radiographic or endoscopic findings. In addition, Albu and Tomescu note that the study was significantly underpowered to detect a difference between the 2 treatment groups.
Based on current research available, the overall principle of wide maxillary antrostomy reflects the nature of inflammatory disease requiring surgical intervention and adequate postoperative care. In fact, for severe disease, 2 clinical studies have shown a benefit through extending the antrostomy to the maxillary sinus floor (“modified medial maxillectomy” or “mega-antrostomy”) in patients who fail the initial surgical approach. However, in the absence of a nonfunctional maxillary sinus, a wide middle meatal antrostomy is often adequate for the majority of chronic maxillary sinusitis.
Maximal endoscopic techniques in frontal sinus surgery
Chronic frontal sinusitis remains a difficult disease to manage despite advances in medical and surgical therapy. Even in the context of maximal techniques for ESS, inflammatory frontal sinus disease should be managed along a spectrum of graduated surgical procedures. If surgical dissection is warranted, the authors believe that a complete Draf IIa dissection should be the first procedure performed, as it successfully manages the majority of frontal sinus disease. This technique involves the removal of the agger nasi cell and any obstructing frontal recess or supraorbital cells to maximize the anterior-posterior and medial-lateral dimensions of the frontal recess ( Fig. 2 ). In a review of more than 717 frontal sinus procedures for inflammatory disease performed at the University of Pennsylvania, Draf IIa dissection was effective in managing more than 92% of cases in a tertiary sinus center. Even when faced with revision cases, the endoscopic Draf IIa has been shown to achieve an 86.6% patency rate with an average follow-up of 32 months.
