Acta Oto-Laryngologica. 2015; Early Online, 1–5
ORIGINAL ARTICLE
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Outcomes of frontal mucoceles treated with conventional endoscopic sinus surgery
KAZUHIRO NOMURA1, HIROSHI HIDAKA1, KAZUYA ARAKAWA1,2, MITSURU SUGAWARA2, DAIKI OZAWA1, YURI OKUMURA1, YUSUKE TAKATA1 & YUKIO KATORI1 1
Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan and 2Department of Otolaryngology, Tohoku Kosai Hospital, Sendai, Miyagi, Japan
Abstract Conclusion: Conventional endoscopic sinus surgery (CESS) is useful for frontal mucoceles. A patient with short anterior– posterior distance and bone thickening may need an axillary flap, Draf type IIb, or Draf type III procedure. Objective: To present outcomes of frontal mucoceles treated with CESS and predict risk factors for poor outcomes to help define surgical indications. Methods: A consecutive clinical series was reviewed retrospectively. The authors performed CESS without agger nasi resection (Draf type IIa) for 13 frontal sinus mucoceles in 12 patients between October 2011 and July 2013. Patient age, sex, blood eosinophil count, history of operation and co-existence of acute infection were compared. For the condition of the frontal sinus, anterior–posterior distance and width of frontal recess, bone thickening of the frontal recess, bone absorption due to continuous pressure by mucocele and anatomy of the frontal recess was noted. Results: All operations were done without a navigation system. The post-operative course was uneventful in all 12 patients, and all symptoms gradually receded. Among 13 mucoceles, one frontal sinus (7.7%) closed during follow-up.
Keywords: Chronic sinusitis, frontal sinus, mucocele, operative technique, sinus surgery
Introduction Frontal sinus mucocele is one of the most difficult pathologies to treat disease in rhinology. Previously, almost all cases were treated using an external approach with or without removal of the mucocele mucosa [1]. The standard treatment for mucocele subsequently changed to endoscopic marsupialization, leaving the lining mucosa behind [2,3]. Even after marsupialization became the standard treatment for frontal sinus mucoceles, the external approach did not become obsolete, because, unlike the situation for mucocele in the maxilla, an endoscopic-only approach to the frontal sinus is difficult. With the development of new instruments and innovations in endoscopic techniques, the Draf type III/endoscopic modified Lothrop procedure
has recently gained wide use to treat intractable frontal sinus disease (Figure 1A) [4]. Wormald [5] and Wormald and Chan [6] proposed an axillary flap procedure for access to the frontal sinus, making the operative technique easier (Figure 1B). With these new techniques, frontal sinus mucocele is not as difficult to treat as before. Although these new procedures provide a wide operative field and wide fenestration for mucoceles, drilling out agger nasi requires special instruments, such as curved diamond burrs, and is time-consuming. Burn injuries to the floor of the nostril can also result from the friction heat created by drilling. Conventional endoscopic sinus surgery (CESS) (Draf type IIa) is less invasive, saves time, and offers a more secure and functional procedure for frontal mucocele surgery, because the agger nasi is preserved and burrs are not necessary
Correspondence: Kazuhiro Nomura, MD, Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryomachi, Aoba-ku, Sendai, Miyagi 980-8574, Japan. Tel: +81 22 717 7304. Fax: +81 22 717 7307. E-mail: [email protected]
(Received 29 January 2015; accepted 16 February 2015) ISSN 0001-6489 print/ISSN 1651-2251 online 2015 Informa Healthcare DOI: 10.3109/00016489.2015.1021933
2
K. Nomura et al. A
B
TA
TA
AKA TA
All operations were performed under general anesthesia. The uncinate process was resected at the beginning of the operation, but the frontal bony wall of the agger nasi was left untouched. The ipsilateral maxillary sinus and ethmoid air cells were opened in all patients. All frontal ethmoid air cells were opened and the bony septum separating the frontal ethmoid cells and frontal sinus was removed [7]. Microdebriders (Medtronic, Minneapolis, MN) with straight and curved blades were used, but a diamond burr was only used for Patient #4 (Table I), in whom the mucocele was lined with relatively hard bony walls. Mucosa of the bones of the skull base, lamina papyracea, and middle turbinate was preserved. After the procedure, the cavity was packed with either Sorbsan (calcium alginate; Alcare, Japan) or Beschitin-F (chitin-coated gauze; Unitika, Japan) [8]. No additional material was placed in the nasal cavity. Sorbsan is transformed to a gel and is spontaneously removed from the nasal cavity within a few weeks. Beschitin-F was removed on post-operative day 2.
MT
AKA
MT
Operative technique
Y. T
MT
AKA
Y. T
Y. T
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C
IT
IT
IT
Figure 1. Different types of endoscopic frontal sinus drainage. (A) Draf type III. Superior nasal septum and bilateral frontal sinus floors are resected. (B) Axillary flap procedure. Agger nasi is resected. (C) Conventional endoscopic sinus surgery. Agger nasi is preserved. MT, middle turbinate; IT, inferior turbinate.
(Figure 1C) [4]. We report herein on 12 patients in whom CESS was performed for frontal sinus mucoceles. Methods Patients This study retrospectively reviewed 12 patients with frontal mucocele who were treated with CESS between October 2011 and July 2013. Computed tomography (CT) was performed on all patients (Table I, Figure 2). Patients with severe bone formation were not operable on with CESS, and needed more extensive surgery. Such patients were, thus, excluded from this study. Patients were followed-up for at least 12 months. Complete closure of the frontal sinus orifice was defined as failure.
Assessment of the frontal recess Complicated frontal recess is difficult to treat. Types of frontal ethmoidal cells were classified as described by Kuhn [9] and modified by Wormald [10]. Frontal ethmoidal cells were classified according to preoperative CT images. Type 1: single frontal ethmoidal cell above agger nasi cell; type 2: tier of frontal
Table I. Patient characteristics. Patient #
Age
Sex
1
59
2
20
3
51
3
51
4
64
5
36
6 7
Bone thickening
Bone absorption
Acute infection
Op. history
11.0
N
Y
N
N
10.1
N
N
N
N
8.4
10.5
N
N
N
Y
12.5
9.7
N
Y
N
Y
8.9
10.7
Y
Y
N
11.9
15.4
Y
Y
N
11.7
9.8
Y
Y
Y
N
N
4.0
3
Good
8.6
8.4
N
Y
N
N
N
1.0
1
Good
N
0.4
1
Good
N
0.0
0
Good
N
1.0
3
Good
N
2.0
0
Good
N
3.9
3
Closed
AP (mm)
Width (mm)
F
14.4
M
11.2
M M M M
37
M
51
F
8
56
F
7.2
na
Y
Y
N
N
9
44
M
8.6
13.5
N
N
N
N
10
73
F
6.3
11.4
Y
Y
N
N
11
75
F
18.3
9.8
N
Y
N
N
12
61
M
6.1
10.0
Y
Y
N
N
BA
Eos (%)
PJ stage
Outcome
N
0.5
0
Good
Y
3.9
3
Good
N
0.6
3
Good
N
0.6
3
Good
N
N
1.0
3
Good
Y
N
9.0
3
Good
AP, anterior–posterior distance; BA, bronchial asthma; Eos, percentage of eosinophil bloods; PJ stage, Type of frontal recess according to Wormald [10]. 0 = absence of agger nasi cell and frontal ethmoidal cell; 1 = type 1 frontal ethmoidal cell; 3 = type3 frontal ethmoidal cell; na = not available.
Frontal mucoceles treated with conventional ESS
3
A
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B
Figure 2. Examples of frontal mucoceles. Pre-operative CT and post-operative endoscopic view. (A) Patient #3 (Table I). Despite bone thickening and a large frontal bullar cell, good results were obtained. (B) Patient #12 (Table I). Anterior–posterior distance is low and bone thickening is evident. The frontal ostium was closed 3 months post-operatively.
ethmoidal cells above agger nasi cell; type 3: frontal ethmoidal cell that pneumatizes cephalad into the frontal sinus through the frontal ostium but not extending beyond 50% of the vertical height of that frontal sinus; type 4: frontal ethmoidal cell that extends more than 50% of the vertical height of the frontal sinus. In terms of surgical technique, type 1 is simple and type 4 is complicated and, thus, more difficult (with types 2 and 3 between). Anterior–posterior (AP) distance and width of the narrowest point of the frontal recess were measured on CT using OsiriX version 4.1.2 software [11]. Bone thickening is another factor that contributes to surgical difficulty and poor outcomes [12]. We decided whether the bone of ethmoid cells was thick or normal based on intra-operative findings. We judged ethmoid bone that is paper-thin and fractures easily as ‘normal’ and any ethmoid bone that is thicker and firmer than ‘normal’ as having ‘bone thickening’. Other factors that may contribute to poor outcomes Bone absorption of the frontal sinus, existence of acute infection, history of sinonasal operation, and bronchial asthma were also noted as possible risk factors for poor prognosis. Assessment All patients were followed for at least 12 months. Closure of the frontal sinus ostium as observed on a flexible fiberscope was considered as failure. The study was approved by the institutional review board of Tohoku University Graduate School of Medicine.
Results Twelve patients (age range = 23–80 years; mean = 52.3 years) underwent CESS for frontal mucoceles (Table I). One patient had bilateral frontal mucoceles. Among the 13 mucoceles, one closed and the remaining 12 mucoceles were still open by 12 months postoperatively. The narrowing of frontal sinus ostium occurred within the first 6 months after surgery. Mean (± SD) AP distance of the frontal recess was 10.3 ± 2.5 mm (range = 6.1–18.3 mm) on pre-operative CT. Mean width of the frontal recess was 10.8 ± 1.9 mm (range = 8.4–15.4 mm) on pre-operative CT. Bone thickening was observed in six of 13 recesses. Three patients had undergone previous sinus surgery. One patient had bronchial asthma. Blood eosinophil count was within normal limits in all except one patient. The type of frontal recess according to Wormald was mostly type 3 (8/13, 61.5%, Table I) [10]. In our series, eight patients showed type 3 (62%) and two patients had type 1 (15%). Three patients (23%) had frontal mucoceles so large that no agger nasi cells were present. The failed patient had type 3 ethmoidal cells. The maximum percentage of eosinophils in the blood was 9% in Patient 5, who showed good prognosis. The percentage of eosinophils in the blood for the failed patient was 3.9%. Bone absorption was found in 10 of 13 cases (77%), including the failed case. The frontal mucocele that closed had the shortest AP distance (6.1 mm) and below-average width (10.0 mm). Both bone thickening and bone absorption were observed, and the patient had not undergone previous sinus surgery. The frontal recess was type 3, where the frontal ethmoid cell had pneumatized cephalad into the frontal sinus through the
4
K. Nomura et al.
frontal ostium, but not extending beyond 50% of the vertical height of that frontal sinus.
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Discussion Of the 13 frontal mucoleces treated with CESS, one frontal sinus closed during follow-up (7.7%). The characteristics of the closed mucocele was the shortest AP distance (6.1 mm), below-average width (10.0 mm), bone thickening and bone absorption in a patient who had not undergone previous sinus surgery. Logistic regression analysis was not used because of the limited number of patients. Draf type IIa drainage indicates removal of eggshell-like ethmoid cells obstructing the frontal sinus drainage [4]. With Draf type IIa, all frontal ethmoid cell walls are resected, excluding the mucosa and bone of the lamina papyracea, middle turbinate and frontal beak. Draf type IIa includes both CESS and axillary flap procedures, because both procedures leave bone between the middle turbinate and nasal septum. A diamond burr is not necessary for CESS, because ethmoid cell walls are thin and easily removed with cutting forceps. Another benefit of CESS is that bone of the agger nasi is not exposed. Most mucosa of the frontal recess can be preserved with this procedure. Preservation of the mucosa is very important to prevent restenosis. The axillary flap procedure was developed to overcome bone formation as a result of bone exposure using a local mucosal flap [5]. With the axillary flap approach, a burr is needed to resect the bone of the agger nasi. Draf type IIb drainage indicates drilling out of the frontal beak and the bone between the nasal septum and attachment of the middle turbinate. A burr is necessary for this approach, because the bone of the agger nasi and frontal beak is hard and thick. However, burrs confer several disadvantages: (1) the skin of the nostrils is occasionally burnt; (2) not all hospitals are equipped with burrs; and (3) their use is costly and timeconsuming. If the outcome will be the same, a simple technique such as CESS is preferable. In-office drainage of sinus mucoceles instead of operating room drainage showed favorable outcomes [13]. Courson et al. [14] recently published a metaanalysis of surgical management for frontal sinus mucocele. They analyzed 542 frontal mucoceles from 20 studies. Endoscopic and open approaches were comparable in terms of recurrence, with overall recurrence rates of 3.1–10.7%. Nowadays, endoscopic marsupialization is the first choice for normal frontal mucoceles, considering the side-effects associated with open approaches. External approaches should be reserved for cases involving difficult anatomy and untreatable with Draf type III. In their
algorithm, primary frontal mucoceles should be treated with Draf type I, II, or III, depending on the extension, presence of scar, and osteitis. Unlike chronic rhinosinusitis [15,16], the percentage of eosinophils in blood was not a predictor of restenosis in our series. Co-existence of acute infection and previous sinus surgery are also unlikely to represent predictors of poor prognosis. Bone thickening was found in six of 13 mucoceles (46%), including the failed case. Bone thickening occurs as a result of osteitis, which involves inflammatory changes in the underlying bone. In chronic sinusitis, osteitis is associated with severe disease, and affects the degree of improvement in quality-of-life measures after both medical and surgical treatment [12]. Common sites of bone absorption are the orbital roof and posterior wall of the frontal sinus. Bone absorption accompanying sinus mucocele is common. Eleven of 15 patients (73%) with spheno-ethmoid mucocele reportedly displayed bone absorption at the skull base [17]. Bone absorption and bone thickening can co-exist because they exist at different places. The former occurs at the orbital roof and posterior wall of the frontal sinus and the latter occurs at the frontal recess. Figure 2B (patient #12) is the example of co-existence of bone absorption and bone thickening. To the best of our knowledge, the association between bone absorption and poor prognosis has not been debated. The most important factor seems to be the crosssectional area of the frontal ostium. AP distance and width are two factors contributing to area. Mean frontal ostium AP distance was 7.22 ± 2.78 mm and mean transverse diameter was 8.92 ± 2.95 mm [18]. Since AP distance tends to have a more eccentric short distance than transverse diameter, AP distance is more critical than the width of the frontal recess to achieve a patent nasofrontal passage. The types of frontal ethmoidal cells, as classified by Kuhn [9] and modified by Wormald [10], are widely used for planning frontal sinus surgery. In terms of surgical technique, type 1 is simple and type 4 is complicated with difficult surgery. A recent study suggested that limited dimensions of the frontal ostium and presence of type 3 or 4 front-ethmoidal cells are indicators for surgical escalation [19]. Type 3 indicates a frontal ethmoidal cell that pneumatizes cephalad into the frontal sinus through the frontal ostium, but not extending beyond 50% of the vertical height of that frontal sinus on CT [9,10]. Removing bony walls in type 3 cells is sometimes difficult, because the bony wall exists in the frontal sinus. Even specially designed curved instruments cannot always reach and remove the bone. One
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Frontal mucoceles treated with conventional ESS possible reason for failure might be the small remnant of the frontal ethmoid cell. CESS is a simple, physiological procedure for addressing the frontal mucocele. In cases where severe bone thickening is present, a more aggressive approach such as an axillary flap procedure, Draf type IIb or Draf type III drainage is needed. Short AP distance and bone thickening are predictors of restenosis. For this study, we focused on patients treated with CESS, and no further analysis was conducted on patients who received Draf type IIb or III. It is apparent that severely thick bone preventing frontal sinus drainage cannot be removed with simple instruments, and Draf type IIb or III was performed in such cases. Conclusion CESS is useful for frontal mucoceles. Patients with short AP distance and bone thickening may require more invasive procedures such as an axillary flap procedure or Draf type IIb or III drainage. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. References [1] Stiernberg CM, Bailey BJ, Calhoun KH, Quinn FB. Management of invasive frontoethmoidal sinus mucoceles. Arch Otolaryngol Head Neck Surg 1986;112:1060–3. [2] Ikeda K, Takahashi C, Oshima T, Suzuki H, Satake M, Hidaka H, et al. Endonasal endoscopic marsupialization of paranasal sinus mucoceles. Am J Rhinol 2000;14:107–11. [3] Kennedy DW, Josephson JS, Zinreich SJ, Mattox DE, Goldsmith MM. Endoscopic sinus surgery for mucoceles: a viable alternative. Laryngoscope 1989;99:885–95. [4] Weber R, Draf W, Kratzsch B, Hosemann W, Schaefer SD. Modern concepts of frontal sinus surgery. Laryngoscope 2001;111:137–46.
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[5] Wormald PJ. The axillary flap approach to the frontal recess. Laryngoscope 2002;112:494–9. [6] Wormald PJ, Chan SZX. Surgical techniques for the removal of frontal recess cells obstructing the frontal ostium. Am J Rhinol 2003;17:221–6. [7] Moriyama H, Ozawa M, Honda Y. Endoscopic endonasal sinus surgery. Approaches and post-operative evaluation. Rhinology 1991;29:93–8. [8] Okushi T, Yoshikawa M, Otori N, Matsuwaki Y, Asaka D, Nakayama T, et al. Evaluation of symptoms and QOL with calcium alginate versus chitin-coated gauze for middle meatus packing after endoscopic sinus surgery. Auris Nasus Larynx 2012;39:31–7. [9] Kuhn FA. Chronic frontal sinusitis: the endoscopic frontal recess approach. Operative Tech Otolaryngol Head Neck Surg 1996;7:222–9. [10] Wormald PJ. The agger nasi cell: the key to understanding the anatomy of the frontal recess. Otolaryngol Head Neck Surg 2003;129:497–507. [11] Rosset A, Spadola L, Ratib O. OsiriX. An open-source software for navigating in multidimensional DICOM images. J Digit Imaging 2004;17:205–16. [12] Bhandarkar ND, Sautter NB, Kennedy DW, Smith TL. Osteitis in chronic rhinosinusitis: a review of the literature. Int Forum Allergy Rhinol 2013;3:355–63. [13] Barrow EM, DelGaudio JM. In-office drainage of sinus Mucoceles: an alternative to operating-room drainage. Laryngoscope 2014. [Epub ahead of print]. [14] Courson AM, Stankiewicz JA, Lal D. Contemporary management of frontal sinus mucoceles: a meta-analysis. Laryngoscope 2014;124:378–86. [15] Nakayama T, Asaka D, Yoshikawa M, Okushi T, Matsuwaki Y, Moriyama H, et al. Identification of chronic rhinosinusitis phenotypes using cluster analysis. Am J Rhinol Allergy 2012;26:172–6. [16] Newman LJ, Platts-Mills TA, Phillips CD, Hazen KC, Gross CW. Chronic sinusitis. Relationship of computed tomographic findings to allergy, asthma, and eosinophilia. Jama 1994;271:363–7. [17] Yumoto E, Hyodo M, Kawakita S, Aibara R. Effect of sinus surgery on visual disturbance caused by spheno-ethmoid mucoceles. Am J Rhinol 1997;11:337–43. [18] Landsberg R, Friedman M. A computer-assisted anatomical study of the nasofrontal region. Laryngoscope 2001;111: 2125–30. [19] Sama A, McClelland L, Constable J. Frontal sinus mucocoeles: new algorithm for surgical management. Rhinology 2014;52:267–75.
ORIGINAL ARTICLE
Acta Otolaryngol Downloaded from informahealthcare.com by Dalhousie University on 04/14/15 For personal use only.
Outcomes of frontal mucoceles treated with conventional endoscopic sinus surgery
KAZUHIRO NOMURA1, HIROSHI HIDAKA1, KAZUYA ARAKAWA1,2, MITSURU SUGAWARA2, DAIKI OZAWA1, YURI OKUMURA1, YUSUKE TAKATA1 & YUKIO KATORI1 1
Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan and 2Department of Otolaryngology, Tohoku Kosai Hospital, Sendai, Miyagi, Japan
Abstract Conclusion: Conventional endoscopic sinus surgery (CESS) is useful for frontal mucoceles. A patient with short anterior– posterior distance and bone thickening may need an axillary flap, Draf type IIb, or Draf type III procedure. Objective: To present outcomes of frontal mucoceles treated with CESS and predict risk factors for poor outcomes to help define surgical indications. Methods: A consecutive clinical series was reviewed retrospectively. The authors performed CESS without agger nasi resection (Draf type IIa) for 13 frontal sinus mucoceles in 12 patients between October 2011 and July 2013. Patient age, sex, blood eosinophil count, history of operation and co-existence of acute infection were compared. For the condition of the frontal sinus, anterior–posterior distance and width of frontal recess, bone thickening of the frontal recess, bone absorption due to continuous pressure by mucocele and anatomy of the frontal recess was noted. Results: All operations were done without a navigation system. The post-operative course was uneventful in all 12 patients, and all symptoms gradually receded. Among 13 mucoceles, one frontal sinus (7.7%) closed during follow-up.
Keywords: Chronic sinusitis, frontal sinus, mucocele, operative technique, sinus surgery
Introduction Frontal sinus mucocele is one of the most difficult pathologies to treat disease in rhinology. Previously, almost all cases were treated using an external approach with or without removal of the mucocele mucosa [1]. The standard treatment for mucocele subsequently changed to endoscopic marsupialization, leaving the lining mucosa behind [2,3]. Even after marsupialization became the standard treatment for frontal sinus mucoceles, the external approach did not become obsolete, because, unlike the situation for mucocele in the maxilla, an endoscopic-only approach to the frontal sinus is difficult. With the development of new instruments and innovations in endoscopic techniques, the Draf type III/endoscopic modified Lothrop procedure
has recently gained wide use to treat intractable frontal sinus disease (Figure 1A) [4]. Wormald [5] and Wormald and Chan [6] proposed an axillary flap procedure for access to the frontal sinus, making the operative technique easier (Figure 1B). With these new techniques, frontal sinus mucocele is not as difficult to treat as before. Although these new procedures provide a wide operative field and wide fenestration for mucoceles, drilling out agger nasi requires special instruments, such as curved diamond burrs, and is time-consuming. Burn injuries to the floor of the nostril can also result from the friction heat created by drilling. Conventional endoscopic sinus surgery (CESS) (Draf type IIa) is less invasive, saves time, and offers a more secure and functional procedure for frontal mucocele surgery, because the agger nasi is preserved and burrs are not necessary
Correspondence: Kazuhiro Nomura, MD, Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryomachi, Aoba-ku, Sendai, Miyagi 980-8574, Japan. Tel: +81 22 717 7304. Fax: +81 22 717 7307. E-mail: [email protected]
(Received 29 January 2015; accepted 16 February 2015) ISSN 0001-6489 print/ISSN 1651-2251 online 2015 Informa Healthcare DOI: 10.3109/00016489.2015.1021933
2
K. Nomura et al. A
B
TA
TA
AKA TA
All operations were performed under general anesthesia. The uncinate process was resected at the beginning of the operation, but the frontal bony wall of the agger nasi was left untouched. The ipsilateral maxillary sinus and ethmoid air cells were opened in all patients. All frontal ethmoid air cells were opened and the bony septum separating the frontal ethmoid cells and frontal sinus was removed [7]. Microdebriders (Medtronic, Minneapolis, MN) with straight and curved blades were used, but a diamond burr was only used for Patient #4 (Table I), in whom the mucocele was lined with relatively hard bony walls. Mucosa of the bones of the skull base, lamina papyracea, and middle turbinate was preserved. After the procedure, the cavity was packed with either Sorbsan (calcium alginate; Alcare, Japan) or Beschitin-F (chitin-coated gauze; Unitika, Japan) [8]. No additional material was placed in the nasal cavity. Sorbsan is transformed to a gel and is spontaneously removed from the nasal cavity within a few weeks. Beschitin-F was removed on post-operative day 2.
MT
AKA
MT
Operative technique
Y. T
MT
AKA
Y. T
Y. T
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C
IT
IT
IT
Figure 1. Different types of endoscopic frontal sinus drainage. (A) Draf type III. Superior nasal septum and bilateral frontal sinus floors are resected. (B) Axillary flap procedure. Agger nasi is resected. (C) Conventional endoscopic sinus surgery. Agger nasi is preserved. MT, middle turbinate; IT, inferior turbinate.
(Figure 1C) [4]. We report herein on 12 patients in whom CESS was performed for frontal sinus mucoceles. Methods Patients This study retrospectively reviewed 12 patients with frontal mucocele who were treated with CESS between October 2011 and July 2013. Computed tomography (CT) was performed on all patients (Table I, Figure 2). Patients with severe bone formation were not operable on with CESS, and needed more extensive surgery. Such patients were, thus, excluded from this study. Patients were followed-up for at least 12 months. Complete closure of the frontal sinus orifice was defined as failure.
Assessment of the frontal recess Complicated frontal recess is difficult to treat. Types of frontal ethmoidal cells were classified as described by Kuhn [9] and modified by Wormald [10]. Frontal ethmoidal cells were classified according to preoperative CT images. Type 1: single frontal ethmoidal cell above agger nasi cell; type 2: tier of frontal
Table I. Patient characteristics. Patient #
Age
Sex
1
59
2
20
3
51
3
51
4
64
5
36
6 7
Bone thickening
Bone absorption
Acute infection
Op. history
11.0
N
Y
N
N
10.1
N
N
N
N
8.4
10.5
N
N
N
Y
12.5
9.7
N
Y
N
Y
8.9
10.7
Y
Y
N
11.9
15.4
Y
Y
N
11.7
9.8
Y
Y
Y
N
N
4.0
3
Good
8.6
8.4
N
Y
N
N
N
1.0
1
Good
N
0.4
1
Good
N
0.0
0
Good
N
1.0
3
Good
N
2.0
0
Good
N
3.9
3
Closed
AP (mm)
Width (mm)
F
14.4
M
11.2
M M M M
37
M
51
F
8
56
F
7.2
na
Y
Y
N
N
9
44
M
8.6
13.5
N
N
N
N
10
73
F
6.3
11.4
Y
Y
N
N
11
75
F
18.3
9.8
N
Y
N
N
12
61
M
6.1
10.0
Y
Y
N
N
BA
Eos (%)
PJ stage
Outcome
N
0.5
0
Good
Y
3.9
3
Good
N
0.6
3
Good
N
0.6
3
Good
N
N
1.0
3
Good
Y
N
9.0
3
Good
AP, anterior–posterior distance; BA, bronchial asthma; Eos, percentage of eosinophil bloods; PJ stage, Type of frontal recess according to Wormald [10]. 0 = absence of agger nasi cell and frontal ethmoidal cell; 1 = type 1 frontal ethmoidal cell; 3 = type3 frontal ethmoidal cell; na = not available.
Frontal mucoceles treated with conventional ESS
3
A
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B
Figure 2. Examples of frontal mucoceles. Pre-operative CT and post-operative endoscopic view. (A) Patient #3 (Table I). Despite bone thickening and a large frontal bullar cell, good results were obtained. (B) Patient #12 (Table I). Anterior–posterior distance is low and bone thickening is evident. The frontal ostium was closed 3 months post-operatively.
ethmoidal cells above agger nasi cell; type 3: frontal ethmoidal cell that pneumatizes cephalad into the frontal sinus through the frontal ostium but not extending beyond 50% of the vertical height of that frontal sinus; type 4: frontal ethmoidal cell that extends more than 50% of the vertical height of the frontal sinus. In terms of surgical technique, type 1 is simple and type 4 is complicated and, thus, more difficult (with types 2 and 3 between). Anterior–posterior (AP) distance and width of the narrowest point of the frontal recess were measured on CT using OsiriX version 4.1.2 software [11]. Bone thickening is another factor that contributes to surgical difficulty and poor outcomes [12]. We decided whether the bone of ethmoid cells was thick or normal based on intra-operative findings. We judged ethmoid bone that is paper-thin and fractures easily as ‘normal’ and any ethmoid bone that is thicker and firmer than ‘normal’ as having ‘bone thickening’. Other factors that may contribute to poor outcomes Bone absorption of the frontal sinus, existence of acute infection, history of sinonasal operation, and bronchial asthma were also noted as possible risk factors for poor prognosis. Assessment All patients were followed for at least 12 months. Closure of the frontal sinus ostium as observed on a flexible fiberscope was considered as failure. The study was approved by the institutional review board of Tohoku University Graduate School of Medicine.
Results Twelve patients (age range = 23–80 years; mean = 52.3 years) underwent CESS for frontal mucoceles (Table I). One patient had bilateral frontal mucoceles. Among the 13 mucoceles, one closed and the remaining 12 mucoceles were still open by 12 months postoperatively. The narrowing of frontal sinus ostium occurred within the first 6 months after surgery. Mean (± SD) AP distance of the frontal recess was 10.3 ± 2.5 mm (range = 6.1–18.3 mm) on pre-operative CT. Mean width of the frontal recess was 10.8 ± 1.9 mm (range = 8.4–15.4 mm) on pre-operative CT. Bone thickening was observed in six of 13 recesses. Three patients had undergone previous sinus surgery. One patient had bronchial asthma. Blood eosinophil count was within normal limits in all except one patient. The type of frontal recess according to Wormald was mostly type 3 (8/13, 61.5%, Table I) [10]. In our series, eight patients showed type 3 (62%) and two patients had type 1 (15%). Three patients (23%) had frontal mucoceles so large that no agger nasi cells were present. The failed patient had type 3 ethmoidal cells. The maximum percentage of eosinophils in the blood was 9% in Patient 5, who showed good prognosis. The percentage of eosinophils in the blood for the failed patient was 3.9%. Bone absorption was found in 10 of 13 cases (77%), including the failed case. The frontal mucocele that closed had the shortest AP distance (6.1 mm) and below-average width (10.0 mm). Both bone thickening and bone absorption were observed, and the patient had not undergone previous sinus surgery. The frontal recess was type 3, where the frontal ethmoid cell had pneumatized cephalad into the frontal sinus through the
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frontal ostium, but not extending beyond 50% of the vertical height of that frontal sinus.
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Discussion Of the 13 frontal mucoleces treated with CESS, one frontal sinus closed during follow-up (7.7%). The characteristics of the closed mucocele was the shortest AP distance (6.1 mm), below-average width (10.0 mm), bone thickening and bone absorption in a patient who had not undergone previous sinus surgery. Logistic regression analysis was not used because of the limited number of patients. Draf type IIa drainage indicates removal of eggshell-like ethmoid cells obstructing the frontal sinus drainage [4]. With Draf type IIa, all frontal ethmoid cell walls are resected, excluding the mucosa and bone of the lamina papyracea, middle turbinate and frontal beak. Draf type IIa includes both CESS and axillary flap procedures, because both procedures leave bone between the middle turbinate and nasal septum. A diamond burr is not necessary for CESS, because ethmoid cell walls are thin and easily removed with cutting forceps. Another benefit of CESS is that bone of the agger nasi is not exposed. Most mucosa of the frontal recess can be preserved with this procedure. Preservation of the mucosa is very important to prevent restenosis. The axillary flap procedure was developed to overcome bone formation as a result of bone exposure using a local mucosal flap [5]. With the axillary flap approach, a burr is needed to resect the bone of the agger nasi. Draf type IIb drainage indicates drilling out of the frontal beak and the bone between the nasal septum and attachment of the middle turbinate. A burr is necessary for this approach, because the bone of the agger nasi and frontal beak is hard and thick. However, burrs confer several disadvantages: (1) the skin of the nostrils is occasionally burnt; (2) not all hospitals are equipped with burrs; and (3) their use is costly and timeconsuming. If the outcome will be the same, a simple technique such as CESS is preferable. In-office drainage of sinus mucoceles instead of operating room drainage showed favorable outcomes [13]. Courson et al. [14] recently published a metaanalysis of surgical management for frontal sinus mucocele. They analyzed 542 frontal mucoceles from 20 studies. Endoscopic and open approaches were comparable in terms of recurrence, with overall recurrence rates of 3.1–10.7%. Nowadays, endoscopic marsupialization is the first choice for normal frontal mucoceles, considering the side-effects associated with open approaches. External approaches should be reserved for cases involving difficult anatomy and untreatable with Draf type III. In their
algorithm, primary frontal mucoceles should be treated with Draf type I, II, or III, depending on the extension, presence of scar, and osteitis. Unlike chronic rhinosinusitis [15,16], the percentage of eosinophils in blood was not a predictor of restenosis in our series. Co-existence of acute infection and previous sinus surgery are also unlikely to represent predictors of poor prognosis. Bone thickening was found in six of 13 mucoceles (46%), including the failed case. Bone thickening occurs as a result of osteitis, which involves inflammatory changes in the underlying bone. In chronic sinusitis, osteitis is associated with severe disease, and affects the degree of improvement in quality-of-life measures after both medical and surgical treatment [12]. Common sites of bone absorption are the orbital roof and posterior wall of the frontal sinus. Bone absorption accompanying sinus mucocele is common. Eleven of 15 patients (73%) with spheno-ethmoid mucocele reportedly displayed bone absorption at the skull base [17]. Bone absorption and bone thickening can co-exist because they exist at different places. The former occurs at the orbital roof and posterior wall of the frontal sinus and the latter occurs at the frontal recess. Figure 2B (patient #12) is the example of co-existence of bone absorption and bone thickening. To the best of our knowledge, the association between bone absorption and poor prognosis has not been debated. The most important factor seems to be the crosssectional area of the frontal ostium. AP distance and width are two factors contributing to area. Mean frontal ostium AP distance was 7.22 ± 2.78 mm and mean transverse diameter was 8.92 ± 2.95 mm [18]. Since AP distance tends to have a more eccentric short distance than transverse diameter, AP distance is more critical than the width of the frontal recess to achieve a patent nasofrontal passage. The types of frontal ethmoidal cells, as classified by Kuhn [9] and modified by Wormald [10], are widely used for planning frontal sinus surgery. In terms of surgical technique, type 1 is simple and type 4 is complicated with difficult surgery. A recent study suggested that limited dimensions of the frontal ostium and presence of type 3 or 4 front-ethmoidal cells are indicators for surgical escalation [19]. Type 3 indicates a frontal ethmoidal cell that pneumatizes cephalad into the frontal sinus through the frontal ostium, but not extending beyond 50% of the vertical height of that frontal sinus on CT [9,10]. Removing bony walls in type 3 cells is sometimes difficult, because the bony wall exists in the frontal sinus. Even specially designed curved instruments cannot always reach and remove the bone. One
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Frontal mucoceles treated with conventional ESS possible reason for failure might be the small remnant of the frontal ethmoid cell. CESS is a simple, physiological procedure for addressing the frontal mucocele. In cases where severe bone thickening is present, a more aggressive approach such as an axillary flap procedure, Draf type IIb or Draf type III drainage is needed. Short AP distance and bone thickening are predictors of restenosis. For this study, we focused on patients treated with CESS, and no further analysis was conducted on patients who received Draf type IIb or III. It is apparent that severely thick bone preventing frontal sinus drainage cannot be removed with simple instruments, and Draf type IIb or III was performed in such cases. Conclusion CESS is useful for frontal mucoceles. Patients with short AP distance and bone thickening may require more invasive procedures such as an axillary flap procedure or Draf type IIb or III drainage. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. References [1] Stiernberg CM, Bailey BJ, Calhoun KH, Quinn FB. Management of invasive frontoethmoidal sinus mucoceles. Arch Otolaryngol Head Neck Surg 1986;112:1060–3. [2] Ikeda K, Takahashi C, Oshima T, Suzuki H, Satake M, Hidaka H, et al. Endonasal endoscopic marsupialization of paranasal sinus mucoceles. Am J Rhinol 2000;14:107–11. [3] Kennedy DW, Josephson JS, Zinreich SJ, Mattox DE, Goldsmith MM. Endoscopic sinus surgery for mucoceles: a viable alternative. Laryngoscope 1989;99:885–95. [4] Weber R, Draf W, Kratzsch B, Hosemann W, Schaefer SD. Modern concepts of frontal sinus surgery. Laryngoscope 2001;111:137–46.
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[5] Wormald PJ. The axillary flap approach to the frontal recess. Laryngoscope 2002;112:494–9. [6] Wormald PJ, Chan SZX. Surgical techniques for the removal of frontal recess cells obstructing the frontal ostium. Am J Rhinol 2003;17:221–6. [7] Moriyama H, Ozawa M, Honda Y. Endoscopic endonasal sinus surgery. Approaches and post-operative evaluation. Rhinology 1991;29:93–8. [8] Okushi T, Yoshikawa M, Otori N, Matsuwaki Y, Asaka D, Nakayama T, et al. Evaluation of symptoms and QOL with calcium alginate versus chitin-coated gauze for middle meatus packing after endoscopic sinus surgery. Auris Nasus Larynx 2012;39:31–7. [9] Kuhn FA. Chronic frontal sinusitis: the endoscopic frontal recess approach. Operative Tech Otolaryngol Head Neck Surg 1996;7:222–9. [10] Wormald PJ. The agger nasi cell: the key to understanding the anatomy of the frontal recess. Otolaryngol Head Neck Surg 2003;129:497–507. [11] Rosset A, Spadola L, Ratib O. OsiriX. An open-source software for navigating in multidimensional DICOM images. J Digit Imaging 2004;17:205–16. [12] Bhandarkar ND, Sautter NB, Kennedy DW, Smith TL. Osteitis in chronic rhinosinusitis: a review of the literature. Int Forum Allergy Rhinol 2013;3:355–63. [13] Barrow EM, DelGaudio JM. In-office drainage of sinus Mucoceles: an alternative to operating-room drainage. Laryngoscope 2014. [Epub ahead of print]. [14] Courson AM, Stankiewicz JA, Lal D. Contemporary management of frontal sinus mucoceles: a meta-analysis. Laryngoscope 2014;124:378–86. [15] Nakayama T, Asaka D, Yoshikawa M, Okushi T, Matsuwaki Y, Moriyama H, et al. Identification of chronic rhinosinusitis phenotypes using cluster analysis. Am J Rhinol Allergy 2012;26:172–6. [16] Newman LJ, Platts-Mills TA, Phillips CD, Hazen KC, Gross CW. Chronic sinusitis. Relationship of computed tomographic findings to allergy, asthma, and eosinophilia. Jama 1994;271:363–7. [17] Yumoto E, Hyodo M, Kawakita S, Aibara R. Effect of sinus surgery on visual disturbance caused by spheno-ethmoid mucoceles. Am J Rhinol 1997;11:337–43. [18] Landsberg R, Friedman M. A computer-assisted anatomical study of the nasofrontal region. Laryngoscope 2001;111: 2125–30. [19] Sama A, McClelland L, Constable J. Frontal sinus mucocoeles: new algorithm for surgical management. Rhinology 2014;52:267–75.
