Introduction

Chronic rhinosinusitis (CRS) is an inflammatory disease of the nose and paranasal sinuses affecting > 10% of the adult population in Europe and the USA [1]. The most common symptoms observed in patients with CRS are facial pain or pressure, loss of smell, and nasal congestion or discharge. In recent decades, new insights have emerged on the endotyping and phenotyping of CRS that have led to a subdivision beyond chronic rhinosinusitis with nasal polyps (CRSwNP) and chronic rhinosinusitis without nasal polyps (CRSsNP). Classification into primary and secondary CRS and further division into localized (often unilateral) or diffuse (always bilateral) disease based on anatomic distribution has been proposed [1, 2]. Both primary and diffuse CRS can be further divided into type 2 or non-type 2. The clinical phenotypes of diffuse CRS are mainly eCRS and non-eCRS, determined by the histological quantification of eosinophil counts [1]. Treatment decisions for the management of CRS are guided based on this endotype classification. Local corticosteroids remain the main medical treatment for diffuse, bilateral CRS because they play an important role in controlling mucosal inflammation [1, 3]. Additionally, endoscopic sinus surgery (ESS) is considered the golden standard in the surgical management of CRS patients. ESS has several goals, including improving sinus ventilation and drainage, creating a sinus cavity that incorporates the natural ostium, facilitating mucociliary clearances and providing better conditions for local treatment [1, 3,4,5].

The literature on sinus surgery is comprehensive, but there is a lack of standardizing surgical terms and guidelines on indications, the exact timing of surgery in the course of CRS, or the appropriate extent of surgery in primary and revision surgery. The spectrum of surgical procedures for CRS ranges from limited surgery such as dilation of the natural ostia to extensive procedures changing the anatomy and removing all diseased and non-diseased mucosa. There is ongoing debate about the extent of sinus surgery for disease control in CRS and factors determining the extent of surgery (e.g., endotype of CRS, extent of mucosal thickening on CT, intraoperative judgment). This debate is very difficult as terms like “complete surgery,” “functional surgery,” “non-functional surgery,” “extended surgery,” and “radical surgery” are used interchangeably and defined very differently in the literature. Several extended surgical approaches have been proposed, but few studies have examined the short- and long-term outcomes. The aim of this review is to discuss the recent literature on the extent of surgery for CRS and, more specifically, the more extensive forms of surgery such as creating a neo-sinus, “full” functional endoscopic sinus surgery (FESS), reboot surgery, nasalization, and mucoplasty for diffuse bilateral type 2 CRS.

ESS: Success, Indications, and Timing

Treatment of CRS is often a challenge, especially patients with a type 2 endotype tend to be more resistant to medical and surgical therapies, exhibiting a high recurrence rate. Recurrence after ESS is common, but rates largely vary depending on the duration of follow-up. Rates in type 2 CRS range from 20% on short term to 38–80% on long term (10–12 years) [6,7,8,9]. Multiple factors have been associated with polyp recurrence, such as asthma, allergic rhinitis, tissue eosinophilia, and aspirin-exacerbated respiratory disease [8,9,10]. Evidence suggests that more extensive surgery in severe CRSwNP lowers the recurrence rates [11, 12•, 13]. However, there is also evidence to the contrary, with studies unable to detect lower revision rates after more extensive surgery [14, 15]. This should take into account the lack of consistency of reported postoperative medical therapy in studies assessing recurrence rates. Despite these high recurrence rates, the addition of ESS to medical therapy significantly improves symptoms and health-related quality of life [1, 3, 16]. A recent randomized controlled trial showed that ESS plus medical therapy is more effective than medical therapy alone in patients with CRSwNP [17].

Several guidelines recommend appropriate medical therapy (AMT) prior to considering surgical intervention; for example, the EPOS suggests surgery if a 3-month trial of medical treatment fails to improve CRS symptoms [1]. However, there is no consensus on the exact definition, criteria, therapeutic classes, or duration of appropriate medical therapy (AMT) [18]. Since sinus surgery aims to improve symptoms, it seems obvious to perform surgery only in patients with symptomatic disease. Variables such as older age, asthma, prior ESS, and a high preoperative SNOT-22 score were found to be correlated with an improved SNOT-22 change after surgery [19]. A preoperative CT scan is required to confirm the presence and the extent of disease, but the preoperative CT-score, namely, the Lund–Mackay score (LMS), has been shown to correlate poorly with quality-of-life measures [1, 20]. Rudmik et al. made an attempt to standardize surgical indications. They recommend offering ESS to CRS patients who have a CT Lund–Mackay score of ≥ 1, which is, however, a very low threshold, and underwent a trial of at least eight weeks of topical steroids plus an antibiotic course with a post-treatment total SNOT-22 score of ≥ 20. In nasal polyp patients, they advise a CT Lund–Mackay score of ≥ 1 and a post-treatment total SNOT-22 score of ≥ 20 after a course of systemic corticosteroids before considering surgery [21].

Research has been conducted regarding the optimal timing of surgery relative to medical therapy or patient symptoms showing that early intervention after diagnosis of CRS is associated with lower healthcare utilization than intervention after many years of medical management [22]. A comparative audit study by Hopkins et al. revealed that patients with delayed surgery reported less improvement in SNOT-22 scores compared to patients treated at earlier time points; moreover, they found that patients who had surgery earlier in the disease were at decreased risk of developing asthma [23, 24]. These results suggest that delaying surgical intervention may result in worse symptom improvement.

The Extent of Surgery

History and Surgical Terms

Functional

Various surgical procedures of the paranasal sinuses are described in the literature, but in this review we focus on the surgical modification of the paranasal sinuses in diffuse bilateral type 2 CRS. Functional endoscopic sinus surgery (FESS) in diffuse bilateral type 2 CRS aims to create a functional sinus cavity. However, there is no agree-upon definition of what “functional” means clinically. We limit the scope to diffuse bilateral type 2 CRS, but distinguish between chronic rhinosinusitis without nasal polyps and with nasal polyps, as this was most commonly used in the published literature.

Endoscopic sinus surgery (ESS) was introduced in the 1980s by Messerklinger focusing on clearing stenotic clefts and infected ethmoidal cells of diseased mucosa at the anterior ethmoid, as well as providing drainage and ventilation by enlarging the maxillary ostium into the anterior fontanelle [25]. Since the introduction of sinus surgery for CRS, the emphasis has been on relieving ostial obstruction and enhancing ventilation [25, 26]. In subsequent years, several studies conclusively demonstrated a decrease in mucociliary clearance in CRS patients with an improvement of sinonasal mucociliary function resulting from sinus surgery [27]. Mucociliary clearance is directed toward the natural ostium rather than toward the surgically created antrostomy. Additionally, failure to include the natural ostium in a maxillary antrostomy may lead to mucus recirculation through the accessory ostium and disease persistence. These reasons underline the importance of incorporating the natural ostium when creating a neo-ostium. Furthermore, a sinus cavity needs functional mucosa, which underlines the importance of mucosal preservation where possible. Since Messerklinger, CRS has increasingly been treated as an inflammatory disease, where improvement of sinus patency or ventilation alone is insufficient, given the current knowledge of the pathophysiology.

Complete

Furthermore, the concept of “complete” surgery is also a subject of debate within surgical terms, with different criteria for “complete” surgery mentioned in the literature (Table 1). The EPOS proposes the term “full FESS,” indicating a complete sinus opening including anterior and posterior ethmoidectomy, middle meatal antrostomies (likely large), sphenoidotomy, and frontal opening (e.g., Draf IIa) [1]. An observational study examined whether all sinuses should be opened regardless of disease extent or whether surgery should be targeted on affected sinuses. They defined “complete” surgery as bilateral frontal sinusotomy, ethmoidectomy, maxillary antrostomy, and sphenoidotomy and concluded that complete surgery was an independent predictor of greater postoperative SNOT-22 score improvement yet did not achieve clinical significance [28]. Conversely, Ayoub et al. found no clear benefit of extending the surgery beyond the diseased sinuses identified on preoperative imaging [15]. Snidvongs et al. describe “complete” surgery as creating a single sinus cavity in which all frontal, ethmoid, maxillary, and sphenoid sinuses are connected by performing a wide antrostomy, complete sphenoethmoidectomy with either a complete Draf IIa or Draf III [4]. A neo-sinus is created through the complete removal of intersinus septa without drilling or intentional mucosal removal to the periosteal layer, referred to as mucosal-preserving surgery (Figs. 1 and 2) [4]. The rationale supporting this approach lies in the maximalization of postoperative delivery of corticosteroids to the sinonasal mucosa rather than focusing on optimization of ventilation [29]. The Amsterdam Classification of Completeness of Endoscopic Sinus Surgery (ACCESS) is a recently developed scoring system that aims to provide a quantitative measure of the extent of endoscopic sinus surgery [30]. This scoring system addresses access to the sinus based on bony boundaries, as opposed to the Lund–McKay score which focuses on sinus opacification.

Table 1 Criteria of complete surgery
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Fig. 1
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Concept of complete surgery: removal of all intersinus septa A sagittal plane and B coronal plane

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Fig. 2
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Complete surgery

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Extensive and Radical

Finally, we want to elaborate on the term “extensive” surgery. Several studies examined “extensive” surgery in CRS, but each used different definitions, making it impossible to compare outcome data from these studies [31, 32]. The EPOS states that “extended” surgery is used in the same context as “full” but could also include extension beyond confines of sinuses, i.e., skull base, orbit, pterygopalatine, and infratemporal fossa. When significant removal of inflamed or dysfunctional mucosa is done, they refer to “radical” surgery [1]. Consistently, the ICAR guidelines refer to “radical” surgery when significant removal of mucosal tissue or resection of the middle turbinate is performed [3]. The debate in the literature focuses on whether “radical” surgery involves intentional removal of the sinus mucosa to the periosteal layer and whether or not it is intended to be functional at the end of the procedure.

Chronic Rhinosinusitis Without Nasal Polyps (CRSsNP)

It is widely accepted in primary surgery for diffuse, non-type 2, chronic rhinosinusitis without nasal polyposis to perform functional endoscopic sinus surgery in which only the diseased mucosa is removed [1]. The surgical treatment for localized isolated sinusitis is beyond the scope of this article. As mentioned before, the goal in sinus surgery for CRS is to create a functional cavity that facilitates mucociliary clearance, which implies that it is important to include the natural ostium in the antrostomy, since mucociliary clearance is directed toward the natural ostium rather than toward the surgically created opening. Albu and Tomescu performed a prospective randomized study on 133 patients to evaluate the influence of the size of the initial middle meatal antrostomy on the degree of postoperative improvement in maxillary symptoms. They found that a narrowed antrostomy was not correlated with persistent symptoms of maxillary sinusitis and thus supported the concept of minimally invasive sinus surgery [33]. Similarly, a prospective study with 33 CRSsNP patients showed no benefit in terms of relief of symptoms for uncinectomy with additional middle meatal antrostomy compared to simple uncinectomy, of which unknown if patients had a partial or total resection of the uncinate process [34]. However, when considering functional surgery, evidence proved that larger maxillary antrostomies permit more effective distribution of topical nasal steroids [35]. A subset of CRSsNP patients has a Th-2 type inflammation, which may predict higher recurrence and revision ESS and thus may also potentially benefit from more extensive surgery [36]. The surgical management of recalcitrant frontal sinus disease is quite controversial due to the difficult reach and location. A meta-analysis provided evidence to support the use of the Draf III approach in recalcitrant frontal sinus disease following failure of primary ESS; moreover, Barham et al. demonstrated optimal delivery of local therapy in patients with frontal sinus disease after a Draf III procedure [37, 38]. The sphenoid sinus is least frequently affected in CRS and usually occurs within the context of pansinusitis. Only a few studies described extensive approaches for the sphenoid sinus. Leight et al. suggested an intermediate step between a sphenoidotomy and a radical sphenoidectomy or marsupialization, namely, a “sphenoid drill out” procedure [39]. In a small prospective study with 12 patients, of which 6 were diagnosed with CRSsNP, this technique proved to be safe and effective with a high success rate for patients with refractory chronic sphenoid sinusitis [40]. Thus, there are several factors to consider when it comes to the extensiveness of sinus surgery in CRSsNP patients.

Chronic Rhinosinusitis with Nasal Polyps

In contrast to CRSsNP, surgical failure is more common in CRSwNP due to polyp recurrence, resulting in multiple surgeries and difficult-to-treat disease. In western countries, CRSwNP commonly presents with a type 2-high inflammation, which results in extensive mucosal inflammation. Topical corticosteroids play an even more important role in controlling mucosal inflammation in this phenotype by improving symptoms, reducing polyp size, and preventing polyp recurrence after surgery [1]. This emphasizes the need for complete surgery by creating a neo-sinus cavity that allows for restoration of ventilation, drainage, and maximized delivery of topical therapy [4].

Extent of Surgery and Outcomes

Regarding the size of the maxillary ostium, a study in 60 CRSwNP patients showed a better patency rate of a large middle antrostomy compared to an undisturbed maxillary ostium in the early phase after ESS [41]. Since the mucociliary pathway beats toward the natural ostium, it is critical to have a patent natural ostium regardless of the size of the surgical antrostomy. Kim et al. found no significant differences in postoperative outcomes (VAS score, endoscopic scores, or CT scores) between CRSwNP patient groups in whom either the inflamed mucosa was radically (but not completely) removed, or only a part of the mucosa was removed, or in patients in whom only enlargement of the maxillary ostium was performed without any removal of mucosa [42]. This argues against the rationale for radical removal of mucosa.

The anterior ethmoid sinuses are most often targeted in all forms of sinus surgery. In CRSwNP patients, polypectomy and surgery up to the anterior ethmoid were practiced widely, but more extensive approaches are supported since recurrence is often observed in CRSwNP patients. A retrospective review demonstrated that removal of nasal polyps along with full ethmoid clearance can lead to lower revision rates compared to polyp disease removal limited to the anterior ethmoid cavity [31]. The complete removal of the anterior and posterior ethmoid cells also maximizes the therapeutic distribution of topical corticosteroid treatment [35].

Surgical management of chronic frontal sinusitis is a challenge due to complex and variable anatomy, difficult transnasal visualization, and tendency for scarring and restenosis. The goal of frontal sinus surgery in refractory disease is to create a wide frontal ostium to provide adequate ventilation, mucociliary clearance, and access for topical therapy. The endoscopic modified Lothrop procedure (EMLP), otherwise known as Draf III frontal sinusotomy or frontal drill out, has been used as an extended procedure when primary surgery fails. A retrospective study assessed the long-term outcome of EMLP surgery in 229 patients, approximately 50% of whom had CRSwNP, and a mean follow-up period of 45 months. EMLP surgery was successful with a patency rate of 97% (a patent frontal neo-ostium) and only 12 of 229 patients requiring revision EMLP due to persistent symptoms [43]. Consequently, the Draf III procedure proved success in refractory patients resistant to standard ESS [44,45,46]. Bassiouni et al. provided evidence that a Draf III procedure improved long-term outcomes and reduced the risk of revision, especially in CRSwNP patients with asthma or aspirin intolerance [47]. Additionally, the Draf III procedure has been found to be superior in comparison to the Draf IIa procedure in delivering topical irrigation to the frontal sinuses [48, 49]. Consequently, a study on human cadaver heads proved that a Draf III procedure was also superior to a Draf IIb for topical irrigation of the frontal sinus [38].

It is not fully known whether more extended techniques such as Draf III frontal surgery should be performed in primary or in revision surgery. The EPOS guidelines suggest considering primary Draf III in high-risk patients with risk factors such as asthma, CRSwNP, Lund–Mackay score of more than 16, or a narrow frontal ostium (< 4mm) [1].

Nasalization

In 1995, the concept of complete total ethmoidectomy with mucosal removal to the periosteum was proposed for the treatment of nasal polyposis by Jankowski et al., referred to as “nasalization.” This technique focused on optimal resection of the non-olfactory ethmoidal mucosa. At that time, nasalization was defined by systematically removing all the bony lamellae and mucosa within the ethmoid labyrinth, with large opening of the maxillary, sphenoidal and frontal ostia, and middle turbinectomy. The mucosa of the maxillary, sphenoid, and frontal sinuses was left intact (Table 2, Fig. 3) [50]. Given the mucosal preservation of the maxillary, sphenoidal, and frontal sinuses in nasalization, there is again overlap with “full” FESS and neo-sinus ESS, highlighting the inconsistencies in surgical term definitions. Some other studies confirmed the interest of middle turbinate resection in polyposis surgery, but this remains a very controversial topic [51, 52]. A 5-year follow-up study reported lower recurrence rates after nasalization than after conventional ethmoidectomy, 22.7% versus 58.3%, respectively, taking into account that both procedures were performed by different surgeons (Table 3) [11]. Besides, olfaction in the hypo-anosmic group improved considerably at 1 month after nasalization, and scores remained stable until 12 months postoperative. The sense of smell in the normosmic group did not change after surgery and remained stable (Table 3) [53]. The technique was updated by 2018 and stated to eradicate vestigial ethmoid mucosa, i.e., all the mucosa in the lateral masses, and all polyps originating there, whether they are externalized in the middle meatus, olfactory cleft, or sphenoethmoidal recess (Table 2, Fig. 3) [54]. Regarding the middle turbinate, the medial aspect covered with mucosa should be conserved as should the ostial mucosa of each sinus [54]. The rationale of the updated version concerns the maximum safe ablation of the non-olfactory ethmoidal mucosa but justifies complete mucosal resection. The results of applying the updated technique have not yet been assessed. The reported long-term complications include mucocele [55], frontonasal stenosis, and synechiae [54]. A retrospective study demonstrated that the olfactory cleft is a frequent site for nasal polyp recurrence after nasalization and that 54.8% of recurrent polyps are respiratory epithelial adenomatoid hamartoma (REAH) or REAH associated to classical inflammatory nasal polyps [56]. Moreover, they found a mean interval of 9.5 years between primary radical surgery with middle turbinate resection and the first revision surgery [56].

Table 2 Extensive techniques explained by sinus
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Fig. 3
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The green dotted lines show the mucosal areas removed during A reboot surgery, B mucoplasty, C nasalization with middle turbinectomy, and D nasalization without middle turbinectomy. In B, the orange line indicates the position of the endonasal mucosal graft

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Reboot Surgery

Bachert et al. introduced the concept of “reboot” and stated that the surgical approach should be tailored according to the endotype, with considering mucosal sparing surgery for symptomatic but uncomplicated CRSsNP and non-type 2 CRSwNP and “reboot” surgery with complete removal of the inflamed sinus mucosa for moderate-to-severe type 2 inflammation [57]. They hypothesize that removal of the type 2 inflammatory environment allows undisturbed re-epithelialization of the sinus walls. The rationale is supported by a small study showing that inflammation in CRSwNP is not limited to the polyps but is also present in the non-polypoid sinus mucosa, which is not addressed by conventional sinus surgery [58]. The technique starts at the maxillary sinus with a wide antrostomy and removing the sinus mucosa, including the alveolar recess mucosa, to the periosteal layer, leaving the periosteum where possible (Fig. 3). At the level of the ethmoid, reboot surgery aims to remove all the mucosa on the lamina orbitalis fovea ethmoidalis, the lateral aspect of the middle turbinate, and the superior turbinate. A wide access to the sphenoid is made with careful removal of the mucosa, especially form the floor, anterior, and medial walls. If the procedure is combined with a Draf III procedure and complete removal of frontal sinus mucosa to the periosteum, it is referred to as a “full reboot” (Table 2) [59]. Alsharif et al. retrospectively looked at polyp recurrence over a follow-up period of 2 years in 50 CRSwNP patients who underwent either a classical non-reboot ESS, a partial reboot approach with removal of ethmoidal, sphenoidal and maxillary mucosa or a complete reboot with a Draf III procedure, and removal of all frontal sinus mucosa. The relapse rates were found to be 45% in the classical approach, 17% in the partial reboot group, and 8% in the full reboot group (Table 3). They reported a reduction in polyp recurrence and prolongation of recurrence-free time after complete removal of the diseased sinus mucosa in patients with type 2 CRSwNP. In this cohort, there were no reports of severe or lasting complications. They found no short-term healing complications or abnormal scar formation [59]. Gomez et al. examined the olfactory function and recurrence rates in a retrospective study of 168 patients, who had revision surgery and either reboot surgery or regular ESS. Smell scores improved similarly in the reboot and ESS groups until 12 months, which was maintained after 24 months for reboot but not for ESS. Over a 24-month period, the recurrence rates were also significantly lower in the reboot surgery group (Table 3) [12•]. More recently, Pirola et al. investigated the outcome of partial reboot surgery in 30 pluri-operated CRSwNP patients as compared to the results previously obtained in the same patients with classical ESS and reported lower recurrence rates, longer recurrence-free survival and improved quality of life and discontinuation of all oral corticosteroids intake with partial reboot surgery (Table 3) [60•].

Mucoplasty

More recently, the concept of “mucoplasty” was proposed, which is a reconstructive procedure that involves the use of an endonasal mucosal graft after total ethmoidectomy in patients with severe nasal polyposis. The hypothesis is to transfer nasal mucosa not usually associated with nasal polyps, such as the nasal cavity floor mucosa, to an area where polyps frequently develop, thus promoting a possible “polyp-resistant” mucosal growth starting from healthy mucosa [61•]. A total ethmoidectomy and Draf III procedure are performed with complete removal of all the mucosa of the skull base and lamina papyracea, since the graft should be in contact with the bone in all its extensions (Table 2). The graft harvesting is obtained from the ipsilateral nasal cavity floor mucosa and placed in the nasal roof partially covering the anterior ethmoidal artery to posterior covering the posterior ethmoidal artery. Laterally, the graft should reach the angle formed by the lamina papyracea and the ethmoidal roof, covering almost all of the lateral lamella of the cribriform area (Fig. 3) [61•]. Mucoplasty was first described in a pilot study of 10 patients who underwent endoscopic sinus surgery for CRSwNP with subsequent endoscopic mucoplasty in the left nasal cavity. They found a better subjective endoscopic evaluation of healing in the nostril with mucoplasty after 6 months of surgery and reported no immediate postoperative or major complications. The graft placement did not affect the olfaction, as evaluated by the VAS scores, showing a non-significant scoring decrease (Table 3). Moreno-Luna et al. state that endonasal mucoplasty could be effective to reduce local edema associated with less secretions and thus give a better control in the frontal recess, orbital wall, and nasal roof in the postoperative period [61•]. A more recent study in 64 patients examined the benefits of bilateral mucoplasty as a complementary technique to reboot surgery. Significant differences in outcomes, such as the modified Lund–Kennedy (LMK), Meltzer, and Lund–Mackay (LM) scores, and the SNOT-22, were found before and after surgery in both groups, with greater improvement in the mucoplasty group (Table 3) [62•]. Further research is needed to determine the long-term outcomes of mucoplasty.

Table 3 Extensive techniques and reported outcomes
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Conclusions

Endoscopic sinus surgery is effective in the surgical management of CRS. Several guidelines suggest considering ESS following failure of adequate medical therapy. However, we believe that CRS needs to be treated as an inflammatory disease by a combination of local treatment and complete endoscopic sinus surgery to maximize the delivery of these intranasal corticosteroids, especially in severe type 2 CRSwNP. The extent of surgery in CRS depends potentially on the severity of disease and the type of underlying inflammation. Extensive forms of sinus surgery for CRS involve 4 approaches, namely, “full FESS or neo-sinus ESS,” “nasalization,” “reboot surgery,” and “mucoplasty.” The literature is limited in long-term follow-up data, but these results are required to optimally evaluate the effect of these surgical procedures.

Additionally, there is a lack of standardization on surgical terms. According to our interpretation and as mentioned in the EPOS, sinus surgery is “functional” when ventilation and drainage are improved, a sinus cavity is created that incorporates the natural ostium, mucociliary clearance is facilitated, and better conditions are provided for local treatment. Considering these criteria, a sinus obliteration, a sphenoidectomy, and a dual ostium configuration are all forms of “non-functional” sinus surgery. Reboot surgery can be interpreted as “functional” surgery, since healthy re-epithelialization from the preserved nasal mucosa occurs, as in mucoplasty, where healthy mucosa is placed over the periosteum. Complete surgery involves complete removal of all bony partitions within a functional sinus unit, incorporating all natural ostia into the surgical cavity, and the complete removal of diseased, inflamed mucosa or polypoid tissue (Fig. 4). Complete surgery for inflammatory disease is desirable in the context of proper access for local therapy and removal of diseased mucosa.

Fig. 4
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Overview of the extended approaches. Reboot surgery, nasalization, and reboot surgery with mucoplasty have in common that all bony partitions within a functional sinus unit are completely removed, incorporating all natural ostia into the surgical cavity and completely removing diseased, inflamed mucosa or polypoid tissue

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The extent of surgery in CRS depends potentially on the severity of disease and the type of underlying inflammation. A variety of extended endoscopic procedures can be used in the management of recalcitrant chronic rhinosinusitis; however, long-term follow-up results and clear definitions of surgical terms are lacking in the current literature.