Key points
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Preoperative management encompasses appropriate patient selection. With a few exceptions, patients undergoing surgical interventions for frontal sinusitis should have exhausted medical management options.
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The preoperative assessment also includes detailed evaluation of imaging for the integrity of the lamina papyracea, the presence of an extracranial anterior ethmoid artery, and anatomic variants impacting the frontal sinus outflow tract, such as accessory frontal sinus cells.
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A comprehensive informed consent includes frank discussion of the potential for significant adverse events, most notably anosmia, orbital complications, and cerebrospinal fluid rhinorrhea.
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Newer techniques, such as balloon catheter dilation of the frontal sinus, offer a promising and less invasive alternative to more extensive frontal sinusotomies; however, practitioners should recognize their limitations based on individual experience with frontal sinus surgeries, and should not simply perform technically “easier” approaches in situations with complicated anatomy.
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If practitioners have limited comfort with these techniques in cases in which they are indicated, these patients would benefit from referral to surgeons with adequate experience in advanced frontal sinusotomy.
| CSF | Cerebrospinal fluid |
| BCD | Balloon catheter dilation |
| ESS | Endoscopic sinus surgery |
| IGS | Image-guided surgery |
Introduction
The increased utilization of endoscopic sinus surgery (ESS) over the past 30 years has triggered the development of novel approaches along with myriad accompanying technologies. Frontal sinus surgery in particular has undergone an evolution from being among the most extensive of paranasal sinus procedures to a predominantly outpatient, minimally invasive undertaking. Nonetheless, the intimate proximity of the frontal sinus to the skull base and orbit means frontal sinus surgery is still fraught with considerable potential morbidities, rendering a smaller margin for error relative to other sinonasal locations. Although recent advances in optical technologies and instrumentation have improved visualization and improved access, the frontal sinus outflow tract can still be easily disrupted. The rapid proliferation of new technologies over the past 10 years, including drug delivery and balloon catheter dilation (BCD) systems, further reinforces the importance of familiarity with anatomic considerations unique to the frontal sinuses. This review focuses on complications in frontal sinus surgery, both those specific to the frontal sinuses and those similar to the other sinuses, as well as strategies for avoiding deleterious sequelae. Rather than providing an exhaustive review of every possible complication, we focus on the most frequent and impactful complications in the context of common surgical techniques. Our hope is that this review serves as a useful resource for sinus surgeons at all levels, including the resident in training, rhinology fellow, general otolaryngologist, and experienced rhinologist.
Introduction
The increased utilization of endoscopic sinus surgery (ESS) over the past 30 years has triggered the development of novel approaches along with myriad accompanying technologies. Frontal sinus surgery in particular has undergone an evolution from being among the most extensive of paranasal sinus procedures to a predominantly outpatient, minimally invasive undertaking. Nonetheless, the intimate proximity of the frontal sinus to the skull base and orbit means frontal sinus surgery is still fraught with considerable potential morbidities, rendering a smaller margin for error relative to other sinonasal locations. Although recent advances in optical technologies and instrumentation have improved visualization and improved access, the frontal sinus outflow tract can still be easily disrupted. The rapid proliferation of new technologies over the past 10 years, including drug delivery and balloon catheter dilation (BCD) systems, further reinforces the importance of familiarity with anatomic considerations unique to the frontal sinuses. This review focuses on complications in frontal sinus surgery, both those specific to the frontal sinuses and those similar to the other sinuses, as well as strategies for avoiding deleterious sequelae. Rather than providing an exhaustive review of every possible complication, we focus on the most frequent and impactful complications in the context of common surgical techniques. Our hope is that this review serves as a useful resource for sinus surgeons at all levels, including the resident in training, rhinology fellow, general otolaryngologist, and experienced rhinologist.
Preoperative evaluation
Patient Selection and Counseling
As in all surgical procedures, appropriate patient selection is key for avoidance of harmful sequelae. Practitioners should ensure that patients undergoing any frontal sinus procedure have exhausted adequate medical management options. With few exceptions, surgical intervention should be considered only after unsuccessful or partially effective medical treatment has been undertaken. Exceptions include but are not limited to obvious anatomic and structural features interfering with frontal sinus outflow tract, suspicion for neoplasm, frontal sinusitis with impending complications and consideration of other lesions, such as mucoceles, that may have local effects on surrounding critical structures.
Appropriate preoperative counseling is an important step for increasing patient understanding and comfort with surgical intervention. Engaging in a 2-way comprehensive discussion detailing risks, alternatives, and benefits not only improves patient satisfaction, but also facilitates postoperative adherence necessary for a successful outcome. Illustrative of this principle, complaints of inadequate informed consent are among the most consistently cited allegations in litigation related to rhinologic procedures.
Preoperative Review of Imaging
In addition to exhibiting symptomatology and potentially exhausting medical management, there should be documentation of frontal sinusitis via either nasal endoscopy and/or imaging. For chronic disease, imaging is mandatory and can provide important information regarding individual anatomic variation that may impact surgical planning. In addition to evaluating the insertion of the uncinate process, as well as skull base anatomy, including Keros classification, there are several considerations specific to frontal sinus intervention ( Box 1 ). It is important to note the anatomy of the frontal sinus outflow tract, specifically identifying the presence of agger nasi cells, suprabullar cells, supraorbital ethmoid cells, and frontal cells ( Fig. 1 ). The presence of these cells, as well as other processes, such as osteoneogenesis, can impact the extent of frontal sinusotomy, and may also steer the surgeon away from less advanced approaches such as BCD. Preoperative imaging also may be used to determine the necessity for image-guided surgery (IGS) during frontal sinus surgery.
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Attachment of uncinate process
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Frontal sinus asymmetry
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Frontal sinus pneumatization
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Lamina papyracea dehiscence
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Location of extracranial anterior ethmoid artery
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Presence of nasoethmoid cells (agger nasi, suprabullar, supraorbital, frontal cells)
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Presence of osteoneogenesis
Hemostasis
In addition to general overall medical fitness for anesthesia, another factor for consideration is the likelihood of intraoperative hemorrhage. Excessive bleeding and consequently decreased visualization can significantly increase the probability of encountering the complications described later in this article. Hence, the preoperative evaluation should include comprehensive questioning regarding a personal and family history of bleeding diatheses. Further workup, including measurement of coagulation factors, should be undertaken if positive history of bleeding diathesis is elicited.
Optimal visualization is essential for success in ESS, particularly for frontal sinus procedures. Preoperative treatment with vasoconstrictive agents, both topical and infiltrative, is crucial for achieving this goal. Strategies for achieving hemostasis and locations for injection vary tremendously among institutions and practitioners.
Intraoperative techniques and relevant anatomy
Due to the relative novelty of advanced techniques in frontal sinus surgery, there are few sizeable cohorts reporting the rates of specific complications. One single institution analysis retrospectively evaluating approximately 200 patients over a 20-year period noted permanent and “major” complications occurring in 2.7% of patients. Importantly, the remarkable breadth in advances during this time period makes it unclear as to what extent this rate is associated with newer techniques and technologies. Complications discussed in this article are summarized in Table 1 .
| Complication | Prevention | Management |
|---|---|---|
| CSF leak | Avoid removal of the middle turbinate posterior to the coronal plane of frontal sinus posterior table Consider use of IGS in revision cases, cases in which disease is abutting the skull base, cases where compromise of posterior frontal sinus table is suspected |
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| Orbital injury decompression | Evaluate preoperative imaging for dehiscent lamina papyracea, location of uncinate process attachment, location of anterior ethmoid artery |
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| Persistent disease/scarring | Mucosal preservation in frontal sinus outflow tract, can be facilitated by avoidance of power tools; removing nasoethmoid cells, recognizing presence of agger nasi cells, other accessory cells; ensuring position in the true frontal sinus ostium before deploying balloons; confirming location via transillumination |
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| Vascular injury/bleeding | Using appropriate preoperative hemostasis Recognizing location of extracranial anterior ethmoid artery | See above |
| Mucocele | Adequate mucosal handling during ESS | Marsupialization |
Endoscopic Endonasal Frontal Sinusotomy: Basic and Advanced Approaches and Potential Complications
Optimizing visualization through sound technique, such as ensuring appropriate hemostasis and holding an endoscope at the correct position, is paramount in preventing intraoperative disorientation that can complicate endoscopic frontal sinusotomy. Familiarity with the endoscopic frontal sinus anatomy is key in successfully undertaking this endeavor. To review briefly, going superior to the anterior border of a maxillary antrostomy, the frontal sinus can be identified at approximately 1 cm posterior to the anterosuperior attachment of the middle turbinate. One can typically locate the frontal sinus outflow tract by aiming a frontal sinus probe superior and medially away from the medial orbital wall to find the point of entry.
As noted previously, preoperative review of the computed tomography (CT) scan and familiarity with the frontal sinus and surrounding anatomy unique to each individual patient is important for facilitating a safe and successful endoscopic frontal sinusotomy. Intraoperatively, familiarity with the presence of an agger nasi cell is paramount. When present, they must be opened, and a probe can subsequently be used to palpate the posterior wall of the frontal sinus. Furthermore, the superior aspects of both agger nasi cells and suprabullar cells can then be fractured and removed to facilitate visualization of the frontal sinus infundibulum. Failure to recognize an agger nasi cell or suprabullar cell is a mistake that is not uncommon; with this failure, particularly with balloon dilation techniques, the frontal sinus outflow tract may become more obstructed.
Once the bony fragments comprising the agger nasi cell, suprabullar cells, or other frontal cells are downfractured, upbiting forceps can be used to remove these fragments. Adequate mucosal preservation is important in preventing postoperative scarring and stenosis. Many practitioners avoid the use of power tools in this area to facilitate mucosal preservation. This is also a key strategy in the avoidance of long-term sequelae, such as frontal sinus mucocele formation. Sound technique at this stage is among the most important steps in preventing long-term restenosis of the frontal sinus outflow tract. After the surgeon is confident that the frontal recess has been cleared of disease and occluding cells, transillumination is an important step in confirming appropriate dissection. If transillumination is witnessed in the medial canthal region, it is likely that a supraorbital ethmoid cell rather than the frontal sinus was opened, and further dissection is required to complete the frontal sinusotomy. An important caveat to this is how the degree of frontal sinus pneumatization affects transillumination; a patient with a poorly pneumatized frontal sinus (on the side transillumination is being attempted) might not have the light showing up in the typical frontal sinus location.
In summary, the keys to success in the basic endoscopic frontal sinusotomy include comprehensive preoperative review of the CT scan and taking steps to optimize intraoperative visualization and prevent disorientation. Furthermore, other important keys for preventing postoperative scarring and outflow pathway obstruction include confirming not only that the frontal sinus outflow tract is free of disease, but that ethmoid cells (including supraorbital and agger nasi cells) and other frontal cells are adequately addressed.
Endoscopic endonasal frontal sinus surgery now extends beyond those techniques described previously. In recent decades, the Draf techniques for endoscopic frontal sinus surgery have been described and have increased in popularity. Accompanying these approaches, however, are the similar potential complications relating to the frontal sinus outflow tract. In addition to appropriate preoperative planning, familiarity with these techniques is paramount for success, and individuals with limited experience in extended frontal sinusotomy approaches may consider avoiding performing these procedures.
The different Draf approaches result in progressively wider frontal sinus outflow tract, and are described briefly ( Fig. 2 ). A Draf I frontal sinusotomy was essentially described previously, and removes suprabullar, agger nasi, and other ethmoid cells interfering with the frontal sinus outflow tract while preserving the sinonasal mucosa. Draf IIA refers to removal of cells extending into the actual frontal sinus, producing a route of drainage between the lamina papyracea and middle turbinate. This latter technique is helpful for unresolved disease after a failed Draf I sinusotomy. The Draf IIB extended frontal sinusotomy expands this outflow farther medially to the nasal septum, and involves removal of the anterior portion of the middle turbinate. In addition to preventing fibrosis and scarring by adhering to the principles of mucosal preservation as described earlier, disruption of skull base and subsequent cerebrospinal fluid (CSF) rhinorrhea and other intracranial sequelae are additional risks with the Draf IIB procedure. For prevention, the surgeon should ensure that middle turbinate resection is limited to the portion anterior to the coronal plane of the frontal sinus posterior table.
