Pneumatization of crista galli in Pre-adult and Adult Stages/ Neumatizacion de la crista galli en Etapas Pre Adultas y Adultas.
The Crista galli (CG), seen as a ridge in the anterior part of the anterior cranial fossa, is a thick, smooth, triangular bony process that projects upward from the cribriform plate of the ethmoid bone. The posterior border of the CG serves for the attachment of the falx cerebri. Its anterior border, short and thick, articulates with the frontal bone, and presents two small projecting wings, which are received into corresponding depressions in the frontal bone and complete the foramen cecum (Strandring, 2009). The Crista galli is an important structure in the sinonasal region. In humans, the sinonasal region is one of the regions that shows the most frequent anatomical variations. These variations can readily be diagnosed with paranasal computed tomography (CT) scans. Paranasal CT scanning is also valuable in studying the normal structure or variations of paranasal sinuses before endoscopic sinus surgery (Danielsen et al., 2006). One of the sinuses most difficult to reach surgically is the frontal sinus, the canal of which is obliterated or narrowed most frequently by anatomical variations. One of these variations is CG pneumatization (CGP) which is often missed. Crista galli pneumatization can result in infection which shows little response to medical therapy, and therefore requires endoscopic surgery as treatment (Socher et al., 2013). Abnormalities narrowing the bone canals are accepted as risk factors for sinus disease. Moreover, anatomic variations in paranasal sinuses are implicated in the pathogenesis of rhinosinusitis (Fadda et al., 2012).
Crista galli pneumatization and its association with adjacent structures are surgically significant. Visualization of the regional anatomy and its variations will be of help to radiologists and otorhinolaryngologists in their practice.
In recent years, there have been studies reporting that CGP originates from the frontal sinus (Basic et al., 1999; Som et al., 2009). Development of the frontal sinus starts at age 6 or 7 years and continues until adulthood. Parallel to this development, an increase in CGP with advancing age is expected. The purpose of this study was to assess the prevalence of CGP in preadults and adults.
MATERIAL AND METHOD
This retrospective study was carried out on 218 patients (100 males and 118 females) of age 5-54 years referred for paranasal CT scanning at the Department of Radiology, Educational and Research Hospital of Mugla Sitki Kocman University, Mugla, Turkey, in the period between June 2012 and June 2013. The study was approved by the local Ethics Committee. Coronal plan paranasal CT scans suitable for examination of the anatomy and morphology of the sinonasal region were selected for study. The images obtained were categorized according to sex and age groups.
The CT images were obtained using a 16-detector row multidetector CT (MDCT) device (Siemens, Somatom Emotion, USA). The paranasal sinus CT images obtained were of 3 mm slice thickness, pitch 1, 110 kV, and 70 mAs. CT images obtained in the coronal plane and reformatted axial plane were evaluated.
The cases were divided into two age groups, namely, cases of age 18 years and over (97 cases) and cases under age 18 (121 cases). From the images obtained, the site and position of the CG were determined, and the presence of pneumatization in the CG was assessed. In the case of pneumatization, its communication with the frontal sinus was studied. The results were evaluated along with relevant studies in the literature, and their clinical implication is discussed.
In the present study, in total, 218 coronal plane paranasal sinus CT images were evaluated. The mean age of the patients included in the study was 24.15 years (554 years); for cases 18 years and over, mean age was 32.12 years, and for cases under 18, mean age was 14.21 years. Of the 218 patients, 100 (45.9 %) were male and 118 (54.1%) female.
Out of the 218 patients, pneumatization was detected in 21 (9.6 %). Pneumatization was present in 2.1 % (n= 2) of the group of patients under age 18 (n= 97), and in 15.7 % (n= 19) of the group of patients of age 18 and over (n= 121) (Table I). Of the 21 CGPs detected, six communicated with the right frontal sinus and 15 with the left frontal sinus (Fig. 1).
The ethmoid is ossified in the cartilage of the nasal capsule at three centers: one for the perpendicular plate, and one for each labyrinth. During the first year after birth, the perpendicular plate begins to ossify in the center. The cribriform plate is ossified partly from the perpendicular plate and partly from the labyrinths. The ethmoid bone completes its development as a single bone at about 3 years of age. Ossification of the CG is completed in the second year after birth (Standring).
The anatomy of the sinonasal region is complex, quite variable, and frequently shows variations. In their study of 200 rhinosinusitis cases scanned by CT, Fadda et al., reported anatomic variation in the sinosinusal region in 140 (70 %) patients, which is a high prevalence. The rate of CGP, one of the anatomic variations, was variable. The rate of CGP has been reported as 2.4 % by Basic et al., 9.3 % by Fadda et al., 14.1 % by Hajiioannou et al. (2010), and 24 % by Arslan et al. (1999). In our study of coronal and reformatted axial CT scans, we found the total pneumatization rate to be 9.6 %.
Among paranasal sinuses, the frontal sinuses are the last to complete development (de Oliveira et al., 2013). At birth, the frontal sinuses are not yet developed or are absent, but are generally fairly well developed between the 7th and 8th years, only reaching their full size after puberty (Scuderi et al., 1993; Standring). The frontal sinuses complete their development at ages 12-14 in females and at ages 16-18 in males (McLaughlin et al., 2001).
At birth, the ethmoid sinuses are filled with fluid, and their identification is difficult (Marquez et al., 2008). At age 12 years, they reach adult size and are well aerated. Some of the front group ethmoid cells develop in the anterior-superior direction, forming the frontal sinuses.
Although the CG is a structure within the ethmoid complex, there are studies reporting that its aeration is provided by the frontal sinuses (Basic et al.; Som et al.). Basic et al. reported the absence of CGP in 132 children under age 7, and the presence of CGP in four out of 79 children of age 7-12 and in 26 (13 %) out of 200 adults. In his study on 65 cases aged 5-16, Al-Qudah (2008) reported the absence of CGP in the 5-7 age group, and the presence of CGP in one case in the 8-12 age group and in four cases in the 12-16 age group.
In our study, we detected CGP in 2 (2.1 %) out of 97 cases aged under 18 and in 19 (15.7 %) out of 121 cases aged 18 and over. The two cases in the former group were of age 17. Consistent with our findings, Kim et al. (2012) found the prevalence of CGP in 73 cases aged under 18 as 2.7% and in 745 cases aged 18 and over as 13.2%.
In our study, of the 21 CGPs detected in total, six communicated with the right frontal sinus and 15 with the left frontal sinus. Kim et al., have reported that all of 100 pneumatizations, apart from one, communicated with the frontal sinus. The authors also found, that in the case with no communication with the frontal sinus, the bilateral frontal sinuses were not developed, and CGP communicated with the right ethmoid sinus (Kim et al.).
The findings of our study show that CGP increases in adulthood. Considering that the frontal sinus which is in a rudimentary state at birth, can be radiographically detected first at age 6, and attains its full dimensions after puberty, this increase in CGP runs parallel to the development of the frontal sinus. Consequently, this supports the opinion that CGP might originate from the frontal sinus.
The results of the present study have shown that CGP is more frequent in adulthood, and its aeration is associated with the right or left frontal sinus. We are of the opinion that these results can help radiologists and otorhinolaryngologists in their CT evaluations of anatomic variations in the sinonasal region.
Al-Qudah, M. The relationship between anatomical variations of the sino-nasal region and chronic sinusitis extension in children. Int. J. Pediatr. Otorhinolaryngol., 72(6):817-21, 2008.
Arslan, H.; Aydinlioglu, A.; Bozkurt, M. & Egeli, E. Anatomic variations of the paranasal sinuses: CT examination for endoscopic sinus surgery. Auris Nasus Larynx, 26(1):39-48, 1999.
Basic, N.; Basic, V; Jukic, T.; Basic, M.; Jelic, M. & Hat, J. Computed tomographic imaging to determine the frequency of anatomical variations in pneumatization of the ethmoid bone. Eur. Arch. Otorhinolaryngol., 256(2):69-71, 1999.
Danielsen, A.; Reitan, E. & Olofsson, J. The role of computed tomography in endoscopic sinus surgery: a review of 10 years' practice. Eur. Arch. Otorhinolaryngol., 263(4):381-9, 2006.
de Oliveira, A. G.; dos Santos Silveira, O.; Francio, L.A.; de Andrade Marigo Grandinetti, H. & Manzi, F. R. Anatomic variations of paranasal sinuses-clinical case report. Surg. Radiol. Anat., 35(6):535-8, 2013.
Fadda, G. L.; Rosso, S.; Aversa, S.; Petrelli, A.; Ondolo, C. & Succo, G. Multiparametric statistical correlations between paranasal sinus anatomic variations and chronic rhinosinusitis. Acta Otorhinolaryngol. Ital., 32(4):244-51, 2012.
Hajiioannou, J.; Owens, D. & Whittet, H. B. Evaluation of anatomical variation of the Crista galli using computed tomography. Clin. Anat., 23(4):370-3, 2010.
Kim, J. J.; Cho, J. H.; Choi, J. W.; Lim, H. W.; Song, Y J.; Choi, S. J. & Yeo, N. K. Morphologic analysis of Crista galli using computed tomography. J. Rhinol., 19(2):91-5, 2012.
Marquez, S.; Tessema, B.; Clement, P. A. & Schaefer, S. D. Development of the ethmoid sinus and extramural migration: the anatomical basis of this paranasal sinus. Anat. Rec. (Hoboken), 291(11)1535-53, 2008.
McLaughlin, R. B. Jr.; Rehl, R. M. & Lanza, D. C. Clinically relevant frontal sinus anatomy and physiology. Otolaryngol. Clin. North Am, 34(11:1-22, 2001.
Scuderi, A. J.; Harnsberger, H. R. & Boyer, R. S. Pneumatization of the paranasal sinuses: normal features of importance to the accurate interpretation of CT scans and MR images. AJR Am. J. Roentgenol, 160(5):1101-4, 1993.
Socher, J. A.; Santos, P G.; Correa, V C. & Silva, L. C. Endoscopic surgery in the treatment of Crista galli pneumatization evolving with localizated frontal headaches. Int. Arch. Otorhinolaryngol., 17(31:246-50, 2013.
Som, P. M.; Park, E. E.; Naidich, T. P. & Lawson, W. Crista galli pneumatization is an extension of the adjacent frontal sinuses. AJNR Am. J. Neuroradiol., 30(1):31-3, 2009.
Stranding, S. Gray's Anatomy. The Anatomical Basis of Clinical Practice. 40th ed. Philadelphia, Elsevier, 2008.
Department of Anatomy
Mugla Sitki Kocman University
Faculty of Medicine
TETIKER, H.; KOSAR, M. I.; CULLU, N.; SAHAN, M.; GENCER C. U. & DERIN, S. Pneumatization of crista galli in pre-adult and adult stages. Int. J. Morphol., 34(21:541-544, 2016.
* Department of Anatomy, Mugla Sitki Kocman University, Faculty of Medicine, Mugla, Turkey.
** Department of Radiology, Mugla Sitki Kocman University, Faculty of Medicine, Mugla, Turkey.
*** Department of Otolaryngology, Mugla Sitki Kocman University, Faculty of Medicine, Mugla, Turkey.
Caption: Fig. 1. Paranasal CT images from a 17-year-old patient. a, b, c: CGP in the coronal plane and its communication with the left frontal sinus. d: In the same patient, CGP in the axial plane and its communication with the left frontal sinus.
Table I. Number of crista galli pneumatizations according to age group and sex. Pneumatization Yes No n % n % Total <18 years of age Male 1 2.3 42 97.7 43 Female 1 1.9 53 98.1 54 Total 2 2.1 95 97.9 97 >18 years of age Male 7 12.3 50 87.7 57 Female 12 18.8 52 81.2 64 Total 19 15.7 102 84.3 121