Original Research—Sinonasal Disorders Retromaxillary Pneumatization of Posterior Ethmoid Air Cells: Novel Description and Surgical Implications Otolaryngology– Head and Neck Surgery 2016, Vol. 155(2) 340–346 Ó American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0194599816639943 http://otojournal.org Islam R. Herzallah, MD, PhD 1,2 , Faisal A. Saati, MD 2,3 , Osama A. Marglani, MD, FRCSC 2,4 , and Rehab F. Simsim, MD 2 No sponsorships or competing interests have been disclosed for this article. Abstract Objective. Retromaxillary pneumatization of posterior eth- moid (PE) air cells is an area that is yet to have appropriate description in rhinologic literature. Study Design. Case series with chart review. Setting. Tertiary care hospital. Subjects and Methods. First, 524 sides in 262 paranasal sinus computed tomography scans were analyzed: 350 normal sides were examined for PE pneumatization lateral to the sagittal plane of the medial wall of maxillary sinus posteriorly, and 174 diseased sides were similarly reviewed to check how pathology may affect identification and measurements. Following that, 153 operated sides in 84 cases prepared for revision endo- scopic sinus surgery (ESS) were studied for residual diseased cells at different anatomic locations. Results. Overall, retromaxillary PE pneumatization was identi- fiable in 416 of the 524 sides (79.4%). Lateral retromaxillary extension varied from 0.5 to 12.3 mm (mean 6 SD, 4.8 6 2.3 mm). This area of pneumatization is bounded anteroinfer- iorly by the junction between the posterior and superior walls of the maxillary sinus. Three cell types were described depending on the degree of lateral extension (type I, \3 mm; type II, 3-6 mm; type III, .6 mm). This cell, which we refer to as the Herzallah cell , was distinguishable from the anterior ethmoid Haller cell and was found to have residual disease in 50.3% of cases prepared for revision ESS. Conclusion. Retromaxillary extension of PE air cells varies con- siderably and requires attention during ESS. Residual undis- sected retromaxillary cell is a common finding in revision ESS and can contribute to inadequate disease clearance. Keywords posterior ethmoids, paranasal sinus, anatomy variations, ana- tomical classification, lamina papyracea, Haller cell, ethmo- maxillary sinus, sphenomaxillary plate, lateral sphenoid recess, revision functional endoscopic sinus surgery, preven- tion of residual disease, chronic rhinosinusitis, computed tomography, imaging, radiology, nasal polyps, allergic fungal sinusitis Received December 21, 2015; revised February 11, 2016; accepted February 29, 2016. U nderstanding endoscopic paranasal sinus (PNS) anat- omy is the key for safe and effective endoscopic sinus surgery (ESS). Identification of anatomic varia- tions is equally important in preoperative planning and intrao- perative orientation. Therefore, rhinologic literature is rich with studies that describe endoscopic landmarks and the dif- ferent anatomic scenarios that surgeons may encounter. 1-4 Endoscopic, radiologic, and anatomic studies that have helped surgeons better perform ESS are numerous. Examples include description of agger nasi and frontal sinus infundibular cells, providing surgeons with better orientation during the endonasal frontal sinus approach. 5-7 Description of Onodi and Haller cells was similarly valuable in helping appropriate and safer clearance of ethmoid air cells as well as proper sphenoid and maxillary sinusotomies, respectively. 8-10 For the same reason, we have maintained a focus on exploring the endo- scopic anatomy in several projects over the past decade. 11-13 Despite these anatomic descriptions, residual disease after ESS continues to occur and is not uncommon. 14-16 A recent study showed that missed ethmoid cells over the lamina papyracea (LP) and skull base is one of the most common findings in revision sinus surgery. 14 The recent classification of LP position in the endoscopic field was introduced to help surgeons address anterior 1 Department of Otorhinolaryngology, Faculty of Medicine, Zagazig University, Zagazig, Egypt 2 ENT Department, King Abdullah Medical City, Makkah, Saudi Arabia 3 Department of Otolaryngology, Al-Hada Armed Forces Hospital, Taif, Saudi Arabia 4 Department of Otolaryngology, Umm Al-Qura University, Makkah, Saudi Arabia Corresponding Author: Islam R. Herzallah, MD, PhD, Department of Otorhinolaryngology, Faculty of Medicine, Zagazig University, Egypt. Email: [email protected]at SOCIEDADE BRASILEIRA DE CIRUR on August 5, 2016 oto.sagepub.com Downloaded from
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Original Research—Sinonasal Disorders
Retromaxillary Pneumatization ofPosterior Ethmoid Air Cells: NovelDescription and Surgical Implications
Otolaryngology–Head and Neck Surgery2016, Vol. 155(2) 340–346� American Academy ofOtolaryngology—Head and NeckSurgery Foundation 2016Reprints and permission:sagepub.com/journalsPermissions.navDOI: 10.1177/0194599816639943http://otojournal.org
Islam R. Herzallah, MD, PhD1,2, Faisal A. Saati, MD2,3,Osama A. Marglani, MD, FRCSC2,4, and Rehab F. Simsim, MD2
No sponsorships or competing interests have been disclosed for this article.
Abstract
Objective. Retromaxillary pneumatization of posterior eth-moid (PE) air cells is an area that is yet to have appropriatedescription in rhinologic literature.
Study Design. Case series with chart review.
Setting. Tertiary care hospital.
Subjects and Methods. First, 524 sides in 262 paranasal sinuscomputed tomography scans were analyzed: 350 normalsides were examined for PE pneumatization lateral to thesagittal plane of the medial wall of maxillary sinus posteriorly,and 174 diseased sides were similarly reviewed to check howpathology may affect identification and measurements. Followingthat, 153 operated sides in 84 cases prepared for revision endo-scopic sinus surgery (ESS) were studied for residual diseasedcells at different anatomic locations.
Results. Overall, retromaxillary PE pneumatization was identi-fiable in 416 of the 524 sides (79.4%). Lateral retromaxillaryextension varied from 0.5 to 12.3 mm (mean 6 SD, 4.8 6
2.3 mm). This area of pneumatization is bounded anteroinfer-iorly by the junction between the posterior and superiorwalls of the maxillary sinus. Three cell types were describeddepending on the degree of lateral extension (type I, \3 mm;type II, 3-6 mm; type III, .6 mm). This cell, which we referto as the Herzallah cell, was distinguishable from the anteriorethmoid Haller cell and was found to have residual disease in50.3% of cases prepared for revision ESS.
Conclusion. Retromaxillary extension of PE air cells varies con-siderably and requires attention during ESS. Residual undis-sected retromaxillary cell is a common finding in revision ESSand can contribute to inadequate disease clearance.
sinus surgery (ESS). Identification of anatomic varia-
tions is equally important in preoperative planning and intrao-
perative orientation. Therefore, rhinologic literature is rich
with studies that describe endoscopic landmarks and the dif-
ferent anatomic scenarios that surgeons may encounter.1-4
Endoscopic, radiologic, and anatomic studies that have
helped surgeons better perform ESS are numerous. Examples
include description of agger nasi and frontal sinus infundibular
cells, providing surgeons with better orientation during the
endonasal frontal sinus approach.5-7 Description of Onodi and
Haller cells was similarly valuable in helping appropriate and
safer clearance of ethmoid air cells as well as proper sphenoid
and maxillary sinusotomies, respectively.8-10 For the same
reason, we have maintained a focus on exploring the endo-
scopic anatomy in several projects over the past decade.11-13
Despite these anatomic descriptions, residual disease
after ESS continues to occur and is not uncommon.14-16 A
recent study showed that missed ethmoid cells over the
lamina papyracea (LP) and skull base is one of the most
common findings in revision sinus surgery.14
The recent classification of LP position in the endoscopic
field was introduced to help surgeons address anterior
1Department of Otorhinolaryngology, Faculty of Medicine, Zagazig
University, Zagazig, Egypt2ENT Department, King Abdullah Medical City, Makkah, Saudi Arabia3Department of Otolaryngology, Al-Hada Armed Forces Hospital, Taif,
Saudi Arabia4Department of Otolaryngology, Umm Al-Qura University, Makkah, Saudi
Arabia
Corresponding Author:
Islam R. Herzallah, MD, PhD, Department of Otorhinolaryngology, Faculty
Figure 1. At posterior ethmoids (PEs), lamina papyracea (LP)slopes inferolaterally (white arrow). A line is drawn along themedial wall of maxillary sinus (MMS) posteriorly, and degree of ret-romaxillary lateral extension is measured (double-headed arrow).MS, maxillary sinus.
Herzallah et al 341
at SOCIEDADE BRASILEIRA DE CIRUR on August 5, 2016oto.sagepub.comDownloaded from
and Haller cells. Retromaxillary pneumatization was also
analyzed in this study.
Statistical Analysis
Statistical analyses were performed with SPSS 22.0 for
Windows (IBM Corp, Armonk, New York). Interrater relia-
bility was examined via the intraclass correlation coefficient
(ICC) to determine the degree of agreement on measure-
ments between the 2 observers. Measurements were also
compared between right and left sides through paired-
samples t test and between the normal and diseased sides
through independent-samples t test. The significance level
was set at P \ .05.
Results
The average 6 SD age of the 262 patients (524 sides) was
38.6 6 16.0 and 37.02 6 14.9 years in the normal and dis-
eased groups, respectively, with no significant difference
between the 2 groups (P . .05; range, 18-88 and 18-79
years, respectively). Overall, 58.4% of patients were men
and 41.6% women, again with no significant difference in
sex distribution between groups (P . .05).
Findings in Normal Sides (350 Sides)
Pneumatization of PE air cells lateral to MMS line was
identifiable in 275 of the 350 sides (78.6%). In these cases,
lateral extension ranged from 0.5 to 12.3 mm (4.8 6 2.4
mm). This retromaxillary pneumatization was bounded ante-
roinferiorly by the junction between the posterior and super-
ior walls of the maxillary sinus (Figure 2, sagittal view).
When the lateral extension was relatively shallow, this cell
was related mainly to the lower part of the LP (Figure 3A,
left side). As the retromaxillary PEs extended more later-
ally, the inferior orbital wall gradually contributed to the
superior wall of the retromaxillary cell (Figure 3B, 3C).
For descriptive purposes, 3 types of retromaxillary pneumati-
zation were described depending on the degree of lateral exten-
sion: type I, pneumatization of PE air cells lateral to MMS line
is \3 mm; type II, 3-6 mm; and type III, .6 mm. In other
words, type I is a relatively shallow pneumatization; type II is
the median common degree of retromaxillary lateral extension;
and type III is a deep retromaxillary cell (Figure 3).
In the 275 sides with identifiable retromaxillary PE cells,
66 sides (24%) were of type I; 136 (49.5%), type II; and 73
Figure 2. Identification of the retromaxillary posterior ethmoid (RM.PE) in coronal, sagittal, and axial planes. MS, maxillary sinus; SS, sphe-noid sinus.
Figure 3. Degrees of retromaxillary posterior ethmoid lateral extension: (A) type I, \3 mm; (B) type II, 3-6 mm; (C) type III, .6 mm. Inpanel A, on the patient’s right side, there is no retromaxillary pneumatization of posterior ethmoids.
342 Otolaryngology–Head and Neck Surgery 155(2)
at SOCIEDADE BRASILEIRA DE CIRUR on August 5, 2016oto.sagepub.comDownloaded from
(26.5%), type III. Twelve sides had ethmomaxillary sinus,
all of which were of type III pneumatization.
In 59 of 350 sides (16.9%), retromaxillary pneumatiza-
tion was not part of the PEs but was rather caused by ante-
rior extension of the sphenoid into the retromaxillary area
(Figure 4). In the remaining 16 sides (4.6%), no retromax-
illary pneumatization was identifiable, neither from the PEs
nor from the sphenoid sinus (Figure 3A, right side).
The retromaxillary PE air cell, which we also refer to as
Herzallah cell, was distinguishable from the infraorbital
anterior ethmoid pneumatization known as Haller cell,
which is part of the anterior group of ethmoid cells and was
identified in 26 (7.4%) of the examined normal sides
(Figure 5).
The ICC for measurements of PE retromaxillary lateral
extension as taken by the 2 examiners was 0.88 (95% confi-
dence interval: 0.86-0.91) at a P value \.001, indicating
high interrater reliability with statistical significance. There
was no statistically significant difference in measurements
between right and left sides (P . .05).
Findings in Diseased Sides (174 Sides)
Pneumatization of PE air cells lateral to MMS line was identi-
fiable in 141 of the 174 diseased sides (81%). In these cases,
lateral extension ranged from 0.65 to 10.4 mm (4.8 6 2.2
mm). In 25 of 174 sides (14.4%), retromaxillary pneumatiza-
tion was formed by anterior extension of the sphenoid sinus,
while in the remaining 8 sides (4.6%), no retromaxillary pneu-
matization was identifiable, neither from the PEs nor from the
sphenoid sinus. In 6 of the 25 sides with retromaxillary sphe-
noid extension (24%), this area of pneumatization was spared
of the disease that involves the PE air cells (Figure 4).
In the 141 diseased sides with identifiable retromaxillary
PE cells, 34 sides (24.1%) were of type I; 67 (47.5%), type
II; and 40 (28.4%), type III. Five sides had ethmomaxillary
sinus, all of which were of type III pneumatization.
The ICC for measurements of PE retromaxillary lateral
extension as taken by the 2 examiners was 0.87 (95% confi-
dence interval: 0.82-0.90) at a P value \.001, indicating high
interrater reliability with statistical significance. Additionally,
there was no statistically significant difference in the
Figure 5. Although retromaxillary posterior ethmoids (Herzallah [Hz] cells) are partly related to the inferior orbital wall, these should bedifferentiated from the infraorbital anterior ethmoid air cells (Haller [Ha] cells).
Figure 4. Anterior extension (asterisk) of sphenoid sinus (SS) to the posterior wall of the maxillary sinus (MS). RM.PE, retromaxillary pos-terior ethmoid pneumatization: note relationship to lateral sphenoid extension (LS) and upper pterygopalatine fossa (PPF).
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