Supraorbital Ethmoid Cells

Educational Objectives

The goals of this program are to improve the outcome of sinus surgery as it relates to supraorbital ethmoid cells. After hearing and assimilating this program, the clinician will be better able to explain the anatomic relationships and clinical significance of SEC.

Summary

 

Background: developmental variations in frontal and ethmoid sinuses affect anatomy of sinus outflow tract; ramifications of mistaking location during surgery, incomplete opening of outflow tract, or leaving cells behind and unopened include increased cost, serious complications, and death in some cases; several classification schemes based on frontal and ethmoid sinus development; Frederick Kuhn classification — types 1 to 4 frontal sinus cells; also cells known as frontal bullar cells, suprabullar cells, frontal sinus septal cells, and supraorbital ethmoid cells (SEC)

Supraorbital ethmoid cells: aerate frontal bone lateral to lamina papyracea; lie posterolateral to frontal outflow region but anterior to anterior ethmoid artery; ostium found posterior to natural frontal outflow or natural frontal ostium; can be confused intraoperatively; wide variation in prevalence of SEC (5%-65%); higher prevalence in Far East than in Western countries; association between SEC and failed ESS (Chiu and Vaughan, 2004)

Review of anatomy: lateral nasal sidewall made up of several bones, 3 main projections, ie, turbinates, and meata below each turbinate; embryologically, 5 ethmoid turbinals from anterior to posterior, ie, agger nasi, uncinate process, ethmoid bulla, ground lamella, and posterior aspect of posterior ethmoid air cells; variation possible in ethmoid turbinals and aeration patterns; ethmoid sinuses develop first in utero in generalized anterior to posterior direction; reach adult size by 12 to 15 yr of age; multiple aeration patterns exist, including supraorbital cells, Haller cells and Onodi cells; 2 other anterior ethmoid cells include agger nasi and ethmoid bulla; embryologically, agger nasi pneumatized first; ethmoid bulla, key landmark for ESS, typically largest; anterior ethmoid artery — terminal branch from internal carotid artery; considerable variation in position because development separate from aeration of ethmoid cells; on coronal CT, look for classic nipple sign; frontal sinuses — develop from aeration of anterior ethmoid cell up into calvaria; typically, only frontal recess at birth, not frontal sinus; development of frontal sinus completed during teenage years; volume of frontal sinus varies from 1 mL to 15 to 20 mL; usually inverted pyramid shape; typically asymmetric and potentially aplastic; frontal outflow tract — depending on aeration pattern, agger nasi, anterior border; frontal sinus, superior border; middle turbinate, medial border; lamina, laterally; maximum effect of aeration patterns posteriorly, hence discussion of SEC

Association of frontal sinus bony septations and SEC: speaker reviewed CT of 60 consecutive patients (120 sides) to identify presence or absence of frontal sinus bony septations and presence or absence of SEC; excluded patients with previous surgery or trauma; findings — statistically significant association of frontal sinus septations with presence of SEC; conversely, absence of frontal sinus septations correlates with lower likelihood of having SEC

Association of proptosis and SEC: in same database, speaker reviewed ICD9 codes to assess if diagnosed with orbital proptosis and CRS (Comer, 2012); preoperative scans reviewed for presence of SEC and for proptosis; 50 random patients with CRS chosen as controls; exclusion criteria included previous reconstructive surgery of frontal sinus or anterior skull base region or acute causes of proptosis, eg, orbital cellulitis, tumors; findings — orbital proptosis in 16 patients; significant association between presence of proptosis and SEC; 94% rate of SEC in proptotic patients

Take-home message: size of frontal sinus outflow tract critically important for drainage; larger agger nasi associated with decreased anterior-posterior dimensions in outflow tract; patients with smaller outflow tract due to larger agger nasi more likely to fail surgery; SEC associated with failed surgery due to enlargement or failure of recognition; anterior ethmoid artery actually posterior to SEC, and failure to recognize presence of SEC can lead to failed surgery or damage to skull base or to anterior ethmoid artery and associated bleeding; conclusions — if frontal sinus septations seen on preoperative imaging, or clinical or radiographic evidence of proptosis, think of presence of SEC for long-term better results with ESS

 

Readings

Report of the Rhinosinusitis Task Force Committee Meeting. Alexandria, Virginia, August 17, 1996. Otolaryngol Head Neck Surg 117:S1, 1997; Bhattacharyya T et al: Relationship between patient-based descriptions of sinusitis and paranasal sinus computed tomographic findings. Arch Otolaryngol Head Neck Surg 123:1189, 1997; Chiu AG, Vaughan WC: Management of the lateral frontal sinus lesion and the supraorbital cell mucocele. Am J Rhinol 18:83, 2004; Comer BT et al: The association between supraorbital ethmoid air cells and orbital proptosis in patients with chronic rhinosinusitis. Int Forum Allergy Rhinol doi:10.1002/alr.21073, 2012 [Epub ahead of print]; Fokkens WJ et al: EPOS 2012: European position paper on rhinosinusitis and nasal polyps 2012. A summary for otorhinolaryngologists. Rhinology 50:1, 2012; International Rhinosinusitis Advisory Board: Infectious rhinosinusitis in adults: classification, etiology and management. Ear Nose Throat J 76:1, 1997; Krouse JH: Allergy and chronic rhinosinusitis. Otolaryngol Clin North Am 38:1257, 2005; Lund VJ, Kennedy DW: Staging for rhinosinusitis. Otolaryngol Head Neck Surg 117:S35, 1997; Lund VJ, Kennedy DW: Quantification for staging sinusitis. The Staging and Therapy Group. Ann Otol Rhinol Laryngol Suppl 167:17, 1995; Meltzer EO et al: Rhinosinusitis: establishing definitions for clinical research and patient care. J Allergy Clin Immunol 114:155, 2004; Meltzer EO et al: Rhinosinusitis: developing guidance for clinical trials. J Allergy Clin Immunol 118:S17, 2006; Metson R et al: Comparison of sinus computed tomography staging systems. Otolaryngol Head Neck Surg 117:372, 1997; Ragab SM et al: Evaluation of the medical and surgical treatment of chronic rhinosinusitis: a prospective, randomised, controlled trial. Laryngoscope 114:923, 2004; Shields G et al: Correlation between facial pain or headache and computed tomography in rhinosinusitis in Canadian and U.S. subjects. Laryngoscope 113:943, 2003; Smith TL et al: Determinants of outcomes of sinus surgery: a multi-institutional prospective cohort study. Otolaryngol Head Neck Surg 142:55, 2010; Smith TL et al: Medical therapy vs surgery for chronic rhinosinusitis: a prospective, multi-institutional study with 1-year follow-up. Int Forum Allergy Rhinol doi:10.1002/alr.21065, 2012 [Epub ahead of print]; Smith TL et al: Evidence supporting endoscopic sinus surgery in the management of adult chronic rhinosinusitis: a systematic review. Am J Rhinol 19:537, 2005; Stewart MG, Johnson RF: Chronic sinusitis: symptoms versus CT scan findings. Curr Opin Otolaryngol Head Neck Surg 12:27, 2004.

Disclosures

In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, membrs of the faculty and the planning committee reported nothing to disclose.

Acknowledgements

Dr. Comer was recorded at the 10th Annual Probusky Symposium, held June 8-9, 2012, in Augusta, GA, and sponsored by Department of Otolaryngology, Medical College of Georgia at Georgia Health Sciences University. For information about upcoming CME events from Georgia Health Sciences University, please visit georgiahealth.edu/ce. The Audio-Digest Foundation thanks the speakers and the sponsors for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

OT452302

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.

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