Radiographic characterization of the retroantral ethmoid cell

Abstract

Background The retroantral ethmoid cell (RAEC) is defined as a posterior ethmoid cell that pneumatizes inferolaterally behind the posterior wall of the maxillary sinus. The RAEC can present a challenge to otolaryngologists during endoscopic ethmoidectomy due to its concealed location. It is also encountered during the endoscopic transpterygoid approach to the skull base, which requires dissection behind the posterior wall of the maxillary sinus. Because the RAEC is not described in the literature, this study aims to better characterize this anatomic variant. Methods This is a retrospective review of 58 consecutive patients who underwent revision functional endoscopic sinus surgery (FESS) within a 2-year period at a tertiary referral center. Sinus CT scans for this cohort (116 sides total) were reviewed independently by three authors to determine the incidence of the RAEC and the degree of surgical dissection during prior surgery. Results Of the 116 sides included in the study, RAEC was identified in 19 (16%). Furthermore, 14/19 (74%) cells were diseased with evidence mucosal thickening or neo-osteogenesis. Of the 12 sides with RAEC that had evidence of previous posterior ethmoidectomy, 4 (33%) cells were not opened, 6 (50%) were partially opened, and only 2 (17%) were completely opened. Conclusions This study demonstrates the relatively high prevalence of the RAEC in our patient population. The majority of RAECs showed both evidence of disease and that they were not completely opened during previous surgery. Recognition of this anatomic entity may allow for more thorough ethmoidectomy.

Significance of Undissected Retromaxillary Air Cells as a Risk Factor for Revision Endoscopic Sinus Surgery

“…These findings are analogous to those of Herzallah et al, 12 who reported RMCs being present in 79.4% of CTs of sinuses, with 50.3% harboring mucosal disease among patients with revision FESS. However, the current study yielded findings different from those reported by Chapurin et al, 13 who found RMCs in only 16% of CTs of sinuses but that 74% contained diseased mucosa. It is worth mentioning, however, that Chapurin et al 13 uses a somewhat different definition of RMCs (i.e., contained within the posterior maxillary sinus), which may explain the differences in prevalence.…”

“…However, the current study yielded findings different from those reported by Chapurin et al, 13 who found RMCs in only 16% of CTs of sinuses but that 74% contained diseased mucosa. It is worth mentioning, however, that Chapurin et al 13 uses a somewhat different definition of RMCs (i.e., contained within the posterior maxillary sinus), which may explain the differences in prevalence. No patients had isolated RMC disease, and all who required revision FESS in this study had other causes for failure (e.g., pansinusitis, recurrent disease, failure of other sinuses), which indicated that RMC disease, expectedly, is more likely to occur in the more common setting of multiple diseased sinuses, and it would be rare to have isolated opacification of the RMCs.…”

“…For instance, Herzallah et al 12 identified RMCs in nearly 80% of computed tomographies (CT) of the paranasal sinuses, with 50% of them being undissected when prepared for revision surgery. Similarly, Chapurin et al 13 found RMCs in only 16% of CTs, with 74% of them undissected before revision surgery. The purpose of this study was to characterize the prevalence, anatomic dimensions, and clinical significance of RMCs in patients with recalcitrant CRS with and without polyposis who underwent revision FESS.…”

Computed Tomography Image Analysis and Clinical Correlations of Retromaxillary Cells

“…Liu et al 16 analyzed 103 sinus CTs and found that the incidence of RMC was 74.30%. Chapurin et al 17 indicated that the incidence of RMC was 16%, but the CT pictures provided in his paper show the EMS. The difference may be due to the ethnicities, the number of samples, and the different criteria of identifying the RMC.…”

“…To our knowledge, few studies about RMC have been reported. [14][15][16][17] The exact anatomic characteristics was still unclear and it is often confused to some other anatomical structure that is located between the MS and orbit such as EMS, Haler cell, and anterior extension of the sphenoid sinus. The distinction of EMS and RMC is ambiguous and vague particularly.…”