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Otorhinolaryngologia - Head and Neck Surgery Issue 42, October - November - December 2010, pages 8-14
REVIEW
Controversies in the management of frontal sinus mucoceles
Απόψεις στην αντιμετώπιση των βλεννογονοκηλών του μετωπιαίου κόλπου
J. Constantinidis - Professor in Otorhinolaryngology
2nd ORL Dept, Aristotle University, Papageorgiou Hospital
Author for correspondence: J. Constantinidis ORL Dept,
1st floor, Papageorgiou Hospital Efkarpia ring road Thessaloniki Greece
Abstract
Mucoceles of the frontal sinus can extend into the orbit and the anterior cranial fossa. In certain cases, their therapeutic management is difficult and may lead to lethal complications. Surgeon often has to make a decision between
an endonasal and an extranasal, transfacial procedure to provide an adequate access.
The choice of adequate surgical access depends on the localization and extension of the mucocele. In the majority of
cases mucoceles develop in the medial part of the frontal sinus and endonasal, endoscopically supported marsupialization of the mucocele into the nose represents the method of choice. If the mucocele of the frontal sinus cannot
be adequately reached endoscopically an extranasal, osteoplastic procedure is indicated.
Key words: Mucocele, endonasal marsupialization, osteoplastic procedure
Περίληψη
Βλεννοκήλες του μετωπιαίου κόλπου μπορεί να επεκταθούν στον οφθαλμικό κόγχο και στον πρόσθιο κρανιακό βόθρο
προκαλώντας επικίνδυνες για την ζωή του ασθενούς επιπλοκές και καθιστώντας την θεραπεία τους σε ορισμένες περιπτώσεις δύσκολη. Ο χειρουργός θα πρέπει να επιλέξει μεταξύ της ενδορρινικής και εξωρρινικής επέμβασης για να
εξασφαλίσει την καλύτερη προσπέλαση.
Η επιλογή της κατάλληλης προσπέλασης εξαρτάται από την εντόπιση, το μέγεθος και την επέκταση της βλεννοκήλης.
Στις περισσότερες περιπτώσεις οι βλεννοκήλες εντοπίζονται στο μέσω τμήμα του μετωπιαίου κόλπου και η ενδορρινική, ενδοσκοπική μαρσιποποίηση της βλεννοκήλης αποτελεί την θεραπεία πρώτης επιλογής. Εάν η βλεννοκήλη δεν είναι δυνατόν να προσπελαστεί ενδοσκοπικά τότε η εξωρρινική, οστεοπλαστική τεχνική διάνοιξης του μετωπιαίου κόλπου
μπορεί να μας εξασφαλίσει ικανοποιητικά λειτουργικά και αισθητικά αποτελέσματα.
Λέξεις κλειδιά: Βλεννοκήλη, ενδορρινική μαρσιποποίηση, οστεοπλαστική τεχνική
Introduction
Mucoceles of the paranasal sinuses are chronic expanding lesions filled with sterile mucus and shed epithelial
cells. An increasing accumulation and retention of mucus
develops when mucosal discharge is obstructed. This can
lead to thinning and destruction of one or more walls of the
paranasal sinuses. If the mucocele becomes infected, then
the appropriate term to describe the lesion is mucopyocele
(Howarth, 1921). In histopathologic terms a mucocele is
a cystic cavity with mucoperiostal walls which are in turn
lined with cuboid respiratory epithelium exhibiting chronic
inflammatory alterations (McHenry et al., 1960).
Pathophysiology
Mucoceles mostly develop in the frontal sinus and less commonly in the ethmoid cell system or in the maxillary and
sphenoid sinuses. The two most frequent causes of frontal mucoceles are: 1. Inflammatory changes and 2. Post-
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traumatic or post-interventional induced scarring of the
nasofrontal duct. Evans reviewed 46 patients with frontoethmoidal mucoceles. Twenty-two patients (48 %) suffered
prior nasal obstruction from polyps (Evans, 1981).
Rarely benign tumors such as osteomas and fibrous dysplasia or malignant and metastatic tumors can obstruct the infundibulum and lead to mucocele development. However, in
a variety of cases, the etiology remains unclarified. Disturbances of secretion transport, pathologic pneumatization
processes, atypical growth of mucosa due to enhanced bone
resorption induced by increased fibroblast activity, and increased production of prostaglandins and leukotrienes have
been discussed as possible causes (Lund et al., 1988).
Mucocele infection or an expansive overgrowth of a frontal
sinus mucocele can result intracranial and orbital complications. Surgical intervention is the only therapeutic option
in such cases. While mucoceles of the ethmoid cell system,
maxillary and sphenoid sinuses can be marsupialized into
the nose without problems through an endonasal approach,
the choice of the procedure in the case of frontal sinus mucoceles is dependent on the localization and extent of the
mucocele.
The complaints of patients with a mucocele of the frontal
sinus vary and depend on the localization and growth behavior of the mucocele. If the mucocele does not transgress
the frontal sinus boundaries, frontal cephalalgias and varying frontal tenderness above the mass represent the most
frequent complaint.
Frontal cephalalgia was the most common complaint among
56 patients with mucoceles of the frontal sinus reported by
Bordley und Bosley. It occured in 54 of 56 cases (Bordley and
Bosley, 1973). Eight of the nine patients with invasive frontoethmoidal sinus mucoceles reported by Stiernberg et al.,
described frontal pain as their main complaint (Stiernberg
et al., 1986).
If the contents of the mucocele become infected, local and
systemic signs of inflammation appear. The continuous secretion of mucus causes an increase in pressure, leading
to osteolysis and devascularization of the bone. Moreover,
osteolytic mediators within the mucocele appear to be responsible for the aggressive nature of these mucoceles
(Lund et al., 1993).
Mucoceles of the frontal sinus can extend inferiorly into the
orbits, the adjacent paranasal sinuses and the nasal cavity, posteriorly into the anterior cranial fossa, and anteriorly into the soft parts of the forehead and the upper eyelid
region. If intraorbital growth develops as a consequence of
destruction of the orbital roof, diplopia, proptosis and bulb
motility disturbances occur. While lesions of the optic nerves
occur more frequently in mucoceles of the sphenoid sinus
and the posterior ethmoid, loss of vision is found very rarely
in mucoceles of the frontal sinus and the anterior ethmoids.
Compression of the optic nerve with associated inflammation of its blood vesssels lead to neuritis of the optic nerve
which is considered to be the cause of this condition (Fujitani et al., 1984). The prognosis of visual function depends
on the duration of infection (Fujitani et al., 1984).
Destruction of the posterior frontal sinus wall results in a
direct connection between the mucocele and the epidural
space. Although the dura can resist against the pressure
exerted by the mucocele and a possible infection, intradural growth with severe complications like CSF leak, meningoencephalitis and pneumocephalus can develop in very
rare cases (Koike et al., 1996).
Computed tomography (CT) is currently the diagnostic
method of choice for paranasal sinus pathology. On the basis of three-dimensional reconstructions the localization
and extent of a mucocele can be precisely determined and
possible bone erosion diagnosed.
Moreover, the surgeon obtains important information on the
individual anatomy of the frontal sinus and the other paranasal sinuses. This knowledge is an important prerequisite
for planning surgical interventions. Magnetic resonance
imaging (MRI) is very helpful in differentiating mucoceles
from meningo-encephaloceles and tumors. In addition demarcation of mucoceles and soft-tissue structures is easier
in the event of intracranial or intraorbital growth.
Magnetic resonance imaging (MRI) is very helpful in differentiating mucoceles
from meningo-encephaloceles and tumors and in demarcating mucoceles
and soft-tissue structures in the event of intracranial or intraorbital growth.
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Fig. 1a-b: Mucocele of the right frontal sinus with intraorbital extension.
(a). Coronal CT, preoperatively. (b). Endoscopic intraoperative view after marsupialization
of the mucocele.
Surgical management
Surgical intervention represents the only therapeutic option. The choice of adequate surgical approach depends on
the localization and extension of the mucocele. Furthermore, the individial anatomy - including modifications resulted from earlier operations - as well as the need for a
follow-up of the patient play an important role in the choice
of surgical approach in order to avoid recurrences.
According to our experience most mucoceles develop in the
medial part of the frontal sinus. In most cases the cause is
an earlier endonasal or extranasal frontal sinus operation
or significant nasal polyposis which can lead to scarring or
obstruction of the nasofrontal duct and the frontal recess.
In these cases endonasal, endoscopically and microscopically supported marsupialization of the mucocele into the
nose represents the method of choice (Fig. 1). This approach allows the normal mucosa and possibly the existing bony boundaries of the frontal sinus infundibulum to be
preserved to a large extent (Iro and Hosemann, 1993). For
the patient the intervention bears little discomfort and the
complication rate is low (Kennedy et al., 1989; Wigand and
Hosemann, 1991). Due to the enhanced accuracy and safety
of the available auxiliary optical instruments the local findings can be endoscopically monitored postoperatively in the
ethmoid and the frontal sinus without problems (Hosemann
et al., 1992; Benninger and Marks, 1995).
If a mucocele of the frontal sinus cannot be reached through
an endonasal approach and an adequate drainage function
cannot be garanteed, an extranasal, transfacial procedure
is indicated.
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Important objectives of surgical therapy should encompass
the following:
1. Reliable sanitation of the mucocele of the frontal sinus
including, if necessary, the management of intracranial and
intraorbital complications.
2. Drainage of the mucocele into the nose, either by preservation or extension of the natural frontal sinus infundibilum
or complete removal of the mucocele and the mucosa of the
frontal sinus and reliable closure of the frontal infundibulum.
3. Preservation or reconstruction of the anterior wall of the
frontal sinus to protect the frontal lobe of brain and reconstruction of the contour of the forehead (Constantinidis et
al, 2001).
After osteoplastic incision of the frontal sinus the adopted
course of the procedure depends on the individual anatomy
and history of the patient, as well as on the overall pathological condition of the mucosa of the nasal and paranasal
sinuses.
In the event of a frontal sinus of overall small size, a nonsignificant history and otherwise inconspicuous mucosal
conditions, we drain the mucocele into the nose by applying
a median drainage. Damage to the mucosa in the region of
the posterior wall of the frontal sinus and the infundibulum
is avoided as far as possible to prevent stenosis development caused by circular scar formation.
The danger of a recurrent mucocele is distinctly increased:
1. in cases involving invasive mucoceles located far laterally
and behind a narrow recess,
2. in patients having undergone a transfacial frontal sinus
operation (using the Killian or Lynch-Howarth procedure)
and
3. in patients requiring recurrent surgery who exhibit predisposing factors such as analgesics intolerance (Schaefer
and Close, 1990). In our experience, obliteration of the frontal sinus has proven successful in such patients (Fig. 2).
The success of obliteration depends on the careful extirpation of the mucosa, the permanent closure of the nasofrontal duct and the choice of appropriate obliteration material.
Complete removal of the mucosa cannot be achieved solely
by ablating the mucosa, as growth of the mucosal tissue
can reach into recesses and fissures of the bone (Donald,
1979).
The inner bone layer should therfore always be additionally drilled with a diamond bur. The microscope is an indispensible tool to remove the mucosa from the dura and the
periorbits. Closure of the nasofrontal duct aims to prevent
an ascending frontal sinus infection and displacement of
transplanted material into the nose. Moreover, the growth
of nasal mucosa upwards in the direction of the frontal sinus
is prevented. To date there is no ideal obliteration material.
Fat, which is the most widely used obliteration material, is
associated with a varying degree of necrosis, resorption and
development of connective tissue (Smahel, 1989; Weber et
al., 1995b).
If large portions of the posterior frontal sinus wall are destructed in association with substantial epidural spread of
the mucocele, or intracranial complications are present, we
perform cranialization of the frontal sinus by complete removal of the posterior wall. These cases require cooperation
with a neurosurgeon and possibly an osteoplastic approach
by frontal craniotomy (Denneny and Davidson, 1987).
Occasionally it may also be necessary to partly or completely remove the posterior frontal sinus wall in the framework
of a planned obliteration procedure. Only this way is possible to retract the meninx enough so as to ensure complete
removal of the mucosa from recesses reaching the lesser
wing of the sphenoid.
Fig. 2a-c: Mucocele of the right frontal sinus with destruction of the
posterior wall and intraorbital extension. (a).Patient after the initial
Lynch procedure. (b). Coronal CT, preoperatively. (c). Obliteration of
the frontal sinus with abdominal fat.
The success of obliteration depends
on the careful extirpation of the mucosa,
permanent closure of the nasofrontal duct
and the choice of appropriate
obliteration material. Complete removal
of the mucosa cannot be achieved solely
by ablating the mucosa, as growth of the
mucosal tissue can reach into recesses
and fissures of the bone.
An extradural dead space is formed once the posterior frontal sinus wall has been removed. This space is obliterated
by expansion of the frontal brain within a period of several
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weeks or months. In children the filling of this dead space
is attained after 7 days at the earliest, which is much faster
than in adults (Spinelli, 1994).
To achieve immediate closure of this dead space and to
avoid scarred adhesions between the dura and the anterior
wall of the frontal sinus we seal the extradural dead space
with abdominal fat after every cranialization of the frontal
sinus. The fat forms a soft buffer zone between the dura and
the anterior frontal sinus wall. This zone gradually becomes
smaller due to a partial transformation to scar tissue.
The vitality of the fatty tissue, as well as the extension of the
frontal brain can be postoperatively assessed by magnetic
resonance tomography of the paranasal sinuses (Weber et
al., 1995b, Constantinidis et al., 2005).
Overall, long-term results are a prerequisite for definite
conclusions on frontal sinus interventions, since recurrences or complications can still develop many years after
primary surgical intervention. Especially in the context of
invasive frontal sinus mucoceles a potential recurrence
should be treated as early as possible due to the danger of
lethal complications. Therefore we recommend control MRI
scans 1, 2, and 5 years after surgery or immediately when
symptoms recur.
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