European Journal of Radiology 82 (2013) 802–805 Contents lists available at SciVerse ScienceDirect European Journal of Radiology journa l h o me pa ge: www.elsevier.com/locate/ejrad Assessment of the lacrimal recess of the maxillary sinus on computed tomography scans Paulo de Lima Navarro, Almiro José Machado Júnior * , Agrício Nubiato Crespo Discipline of Otorhinolaryngology, School of Medical Sciences - Unicamp - Campinas - São Paulo - Brazil a r t i c l e i n f o Article history: Received 11 September 2012 Received in revised form 3 December 2012 Accepted 21 December 2012 Keywords: Maxillary sinus Paranasal sinuses Endoscopic surgery Lacrimal apparatus a b s t r a c t Objective: To assess the frequency of the lacrimal recess in the maxillary sinus (MS) in computed tomo- graphy (CT) of the paranasal sinuses. Methods: CT of the paranasal sinuses (CT PNS) done in a total of 78 patients. According to the discoveries, the MS were classified in two types: anterior or lateral. Results: 41 CT PNS of 41 patients of a total of 78 patients preselected were excluded. 37 CT of the paranasal sinuses from 37 patients, in a total of 68 maxillary sinuses were studied. In the 33 right maxillary sinuses, 10 lacrimal recesses were found, 9 from male patients. Eleven left maxillary sinuses with lacrimal recess were found from a total of 35 left maxillary sinuses. Conclusion: From the analysis of 68 MS, a frequency of 30.9% of lacrimal recesses in the maxillary sinuses in CT was observed. © 2012 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Precise anatomical knowledge is indispensable for any surgeon. Otorhinolaryngological surgery involving the paranasal sinuses, especially when endoscopy-assisted, highlights the importance of such knowledge because of the close relationship between the nasal cavity and prime anatomical elements like the encephalon, hypophysis and ocular globes with their optical nerves, and also because of important vascular elements such as the internal carotid arteries, ethmoidal arteries and cavernosum sinus [1,2]. In the inte- rior of the nasal cavity, the lateral wall can be distinguished, due to the presence of such structures as the nasal conchae, uncinate pro- cess, infundibulum and ethmoidal bulla. Its most anterior portion presents important structures such as the ethmoidal cells of the agger nasi, lacrimal sac and nasolacrimal duct (NLD) [3–5]. The wall of the nasal cavity is also the medial limit of the maxillary sinus (MS), which in its most anterior portion may present the anterior or lacrimal recess, thus named due to its proximity to the lacrimal sac and the NLD [6–8]. This recess is only cited in a few reports in the literature, without great comprehension of its correlation with the lacrimal sac and the NLD [1,2]. * Corresponding author at: Rua Maria Monteiro, 841 ap 11 Cambuí, 13025-151 Campinas, SP, Brazil. Tel.: +55 19 32535472, fax: +55 19 35217523. E-mail address: almirom@ig.com.br (A.J. Machado Júnior). The anatomical relationship between the MS and the LND has gained wider importance with the advent of endoscopy-assisted microsurgery and nasosinusal surgery and because of increas- ing usage of nasal endoscopy for performing middle meatotomy and transnasal dacryocystorhinostomy [9–17]. In cases of middle meatotomy, enlargement of the main ostium of the maxillary sinus presents higher risk of undergoing stenosis if there is manipula- tion of its anterior portion, where it is close to the NLD. Presence of the lacrimal recess in the maxillary sinus, anterior to the NLD, weakens the osseous lamina that covers it, with higher risk of fracturing during tissue resection [18,19]. In cases of endoscopy- assisted transnasal dacryocystorhinostomy, as well as the need for great mastery of the surgical instruments that is inherent to the technique, the surgeon must take into consideration the possibility of anatomical variations of the more anterior and medial portions of the maxillary sinus, i.e. of the area of the lacrimal recess, in order to ensure correct localization of the anatomical structures and avoid areas presenting risks [19,20]. The NLD, the structure involved in dacryocystorhinostomy, has a close anatomical relationship with the MS. The latter may present an anterior projection that advances beyond the limits of the NLD, thus forming an anterior recess. Even though this is a known anatomical variation, this recess is only vaguely cited in a few reports in the literature [1,2,5]. In the different literature sources that we investigated, there were no reports of any classification sys- tem of the maxillary sinus relating to lacrimal recesses. There were no reports on their frequency of occurrence, either. Therefore, the 0720-048X/$ – see front matter © 2012 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ejrad.2012.12.015