Anatomical variations of the frontal sinus: A computed tomography-based study.

Background: The pneumatization of the frontal sinus is variable between individuals, including monozygotic twins. The volumetric anatomic variants of the frontal sinus are classified into aplasia, hypoplasia, medium-sized, and hyperplasia. We aimed to study the frontal sinus morphology in Omani patients using computed tomography (CT) evaluations. Methods: Retrospectively, 1220 frontal sinus CT scans from 610 patients investigated at Sultan Qaboos University Hospital, Oman, from January 2019 to December 2020 were reviewed. The frontal sinus morphology was classified according to the classification proposed by Guerram et al. The Chi-square test was used to determine the influence of sex. Results: With regard to the unilateral occurrence, the most prevalent frontal sinus category observed was medium-sized (13.3%), followed by hyperplasia (7.9%), hypoplasia (5.4%), and aplasia (2%) categories. Similarly, in bilateral occurrence, the most common frontal sinus category observed was medium-sized (53%), followed by hyperplasia (13.1%), hypoplasia (3.4%) and aplasia (2%) categories. Right and left frontal sinus aplasia were observed in 2.1% and 1.8% of cases, respectively. In terms of sex influence, the left unilateral ( p<0.01) and the bilateral hypoplasia ( p<0.05) were significantly higher in females. On the other hand, the left unilateral ( p<0.01) and the bilateral hyperplasia ( p<0.05) were higher in males. Conclusions: The baseline data of frontal sinus category frequencies reported in the present study is helpful in the diagnostic evaluation of sinusitis in the clinical setting. The preoperative recognition of frontal sinus types, particularly frontal sinus aplasia in multiplanar CT scans, is crucial to avoid unexpected complications while performing endoscopic sinus surgery.

Spontaneous Intraparenchymal Tension Pneumocephalus.

Tension pneumocephalus is a treatable emergency that is usually caused by trauma or surgery. We present a rare case of spontaneous tension pneumocephalus. A 64-year-old woman presented with a severe aggravating headache. Computed tomography revealed a large air collection in the brain parenchyma of the right frontal lobe, both lateral ventricles, and the subarachnoid space. Emergent craniotomy was performed because her headache got progressively worse. We found that an abnormal bony protrusion connected the frontal sinus mucosa and the intraparenchymal pneumocephalus. After removal of the bony mass and repair of the defect, the patient immediately recovered and there was no recurrence.

Osteomyelitis of frontal sinus, zygomatic bone and maxilla.

A 52-year male patient reported with loosening of right upper jaw. He has no pain or discharge, or any acute symptoms and systemic disease. Intraoral examination reveals necrosed maxillary bone. He also has no sickle cell disease, hepatitis, HIV or tuberculosis. 3D CT scan reveals destruction of maxilla, maxillary sinus, lateral nasal wall, superior and inferior orbital wall, zygoma and frontal bone(outer table). The clinical diagnosis of osteomyelitis was made. Under general anaesthesia, sequestrectomy was done with the help of Weber-Ferguson incision with infraorbital extension for maxilla, maxillary sinus, zygomatic bone, lateral nasal wall and infraorbital and medial wall of orbit. Frontal sinus region sequestrectomy was done via bicoronal flap. The patient was completely diseased free after 4 years follow-up.

Revisiting global patterns of frontal sinus aplasia utilizing computed tomography.

While frontal sinus aplasia (agenesis, absence) has been proposed as a potential marker in forensic positive identifications, frequency rates are likely dependent upon how presence is defined. This study investigates how two methods of defining frontal sinus presence affects aplasia frequency rates. Using CT scans of 772 adult individuals from diverse geographic regions, frontal sinus presence was assessed two ways: 1) the XR-method- coded present if the sinus extended above the supra-orbital line, and 2) the CT-method- coded present with any indication of the frontal sinus. The XR-method consistently provided higher aplasia frequencies, averaging an 18.31% discrepancy with the CT-method. Method discrepancies were higher in females (averaged-sides: 24.6%) than males (averaged-sides: 13.82%). Oceanian individuals displayed the highest aplasia rates using either method, and the highest discrepancy between methods (averaged-sides: 31.30%); Europeans, displaying the lowest aplasia rates in either method, also displayed the lowest method discrepancy (average-sides: 7.37%). Fisher's Exact tests on the biologically-defined CT aplasia rates indicate females are significantly different from males for unilateral aplasia (p=0.0035); Arctic populations are significantly different from most groups (all p<0.005), exception being Oceanian. Results suggest the lower, biologically-defined CT aplasia rates are more useful in corroborating identifications than the inflated XR frequencies and illustrate the importance of citing aplasia rates from similarly-composed samples. However, due to practicality and resource availability, the XR-method may be more appropriate. Most importantly, reported aplasia rates from one method should be cited in casework utilizing the other method.

The incidence of sinus crista galli in children and adults: a computerized tomography study / La incidencia del sinus crista galli en niños y adultos: un estudio de tomografía computarizada

The pneumatization area in the crista galli region of the ethmoid bone can be called Sinus Crista Galli (SCG). The authors would like to recommend the terminology as sinus crista galli for pneumatized crista galli. Our aims in this study are to determine SCG on three dimensional Computerized Tomography (CT) images, to investigate its frequency, dimension and to emphasize their clinical significance in children and adults. A total of 360 adult images (160 female, 200 male) and 68(43 female, 25 male) pediatric images were examined. The presence SCG was recorded with axial and coronal paranasal sinus CT images. The height, width, anterposterior diameter of the sinus was measured. All the data we obtained from this study were analyzed using the SPSS 18.0 program. Descriptive statistics are shown as mean ± Sdt. Sinus crista galli was found in 17 examined images of the 360 (4.72 %) in adult group. Chronic pansinusitis was detected in 7 of 17 cases. Frontal sinusitis findings were detected in 7 cases. Sinusitis was not observed in 3 cases. The incidence of SCG was found in 4 pediatric images out of 68 (5.88 %). In 1 out of 4 cases, infection was detected in SCG. We did not observe SCG in the pediatric group with 0-7 years of age. Sinus crista galli was found at low rates in adult and pediatric age group. However; relationship was found between these variation and chronic rhinosinusitis. Additionally, detection of SCG in paranasal sinus CT can be provided better results and reduce complications in anterior cranial fossa surgery.

El área de neumatización en la crista galli del etmoides se puede denominar sinus crista galli (SCG). Los autores recomiendan incluir en la terminología anatómica el término sinus crista galli para la crista galli neumatizada. Los objetivos del estudio fueron determinar la SCG en imágenes tridimensionales de tomografía computarizada (TC), investigar su frecuencia, dimensión y enfatizar su importancia clínica en niños y adultos. Se examinaron un total de 360 imágenes de adultos (160 mujeres, 200 hombres) y 68 (43 mujeres, 25 hombres) en imágenes pediátricas. La presencia de SCG se registró con imágenes de tomografía axial y axial del seno paranasal. Se midió la altura, anchura y diámetro anteroposterior del seno del proceso crista galli. Todos los datos obtenidos se analizaron mediante el programa SPSS 18.0. Las estadísticas descriptivas se muestran como media ± DS. El seno crista galli se encontró en 17/360 (4,72 %) de las imágenes examinadas en el grupo de adultos. Se detectó pansinusitis crónica en 7 de 17 casos. Se detectaron hallazgos de sinusitis frontal en 7 casos. Sinusitis no se observó en 3 casos. La incidencia de SCG se encontró en 4 imágenes pediátricas de 68 (5,88 %). En 1 de cada 4 casos, se detectó infección en SCG. No observamos SCG en el grupo pediátrico con 0-7 años de edad. El seno crista galli se encontró en bajas tasas en adultos y en niños. Sin embargo, se encontró relación entre estas variaciones y la rinosinusitis crónica. Además, la detección de SCG en la tomografía computarizada del seno paranasal puede proporcionar mejores resultados y reducir las complicaciones en la cirugía de la fosa craneal anterior.

Bone wax migrates to the orbit in a patient with a frontal sinus abnormality: a case report.

BACKGROUND: Bone wax is the most widely used hemostatic bone sealant because of its availability, ease of use, immediate action, and minimal adverse effects. Several complications have been reported to be associated with the use of bone wax, such as infection, osteohypertrophy, pain, granuloma formation, allergic reaction, and thrombosis. Here, we present a rare complication, namely, bone wax migration, which developed after a craniotomy on a patient who had a frontal sinus abnormality. CASE PRESENTATION: A 51-year-old woman complained of pain and swelling in her left eye accompanied by difficulty opening the left eyelid after undergoing a craniotomy. An examination revealed left eye proptosis with ptosis, eyelid swelling, and increases in intraorbital pressure and intraocular pressure (IOP). According to a CT and an MRI of the orbit, we found that the intraoperative bone wax had migrated to the orbit, thereby causing compression. We also found that the basal frontal sinus of the patient was congenitally defective, which may have induced the migration of the bone wax. Given that the patient recently underwent a craniotomy and given the risks associated with orbital surgery, she refused to undergo a surgery to remove the bone wax. Thus, the patient was administered mannitol intravenously daily, accompanied by topical Timolol, to reduce the intraorbital pressure and IOP. This treatment led to a gradual decrease in IOP and intraorbital pressure, and these parameters remained stable after treatment ended. During the 6-month follow-up, the best corrected visual acuity improved, and ptosis and restricted eye movements also improved significantly. CONCLUSIONS: We report a case of bone wax migration that developed after a craniotomy on a patient who had a congenital defect in the basal frontal sinus. Extra caution should be taken when using bone wax, and a comprehensive understanding of the patient's intracranial anatomy is important for decreasing the incidence of bone wax migration. Additionally, when a patient presents with symptoms of ocular compression, bone wax migration should be considered in addition to typical radiological changes.

Fronto-septal rostrum: prevalence, classification and clinical implications.

OBJECTIVE: To describe a newly observed frontal sinus anatomical variant, the fronto-septal rostrum. METHODS: Consecutive sinus computed tomography scans performed during 2013 were reviewed. The fronto-septal rostrum was defined as a mucosa-lined air space formed in the attachment of the most upper bony nasal septum and the central floor of the frontal sinuses. RESULTS: The study included 400 computed tomography scans from 189 women (47.3 per cent) and 211 men (52.8 per cent), with a mean age of 46.8 years. A fronto-septal rostrum was observed in 122 patients (30.5 per cent), with a mean length of 10.63 mm, width of 4.52 mm, height of 2.18 mm and volume of 63.52 mm3. There was no statistically significant difference related to gender (p = 0.343), and no association between the side of the fronto-septal rostrum and age (p = 0.811) or volume (p = 0.203). CONCLUSION: The newly described fronto-septal rostrum has possible clinical and surgical implications. It is suggested that this aerated space is used in specific surgical indications and its presence evaluated in cases of septal infection.

Coexistence of frontal sinus hypoplasia with maxillary sinus hypoplasia: a radiological study.

The goal of this study was to determine whether frontal sinus hypoplasia coexists with maxillary sinus hypoplasia. Analyzing paranasal CT scans retrospectively, we included 86 patients who had a hypoplastic maxillary sinus at least on one side and 80 patients with bilateral normal maxillary sinuses (control group). We classified hypoplastic maxillary sinuses using the classification system previously defined by Bolger et al. (Otolaryngol Head Neck Surg 103(5):759-765, 1990). We classified the frontal sinuses as aplastic, hypoplastic, medium-sized, and hyperplastic; as previously defined by Guerram et al. (Am J Phys Anthropol 154(4):621-627, 2014). We compared the presence of frontal sinus hypoplasia using Chi-square test between the groups. The mean age of the maxillary sinus group was 43.2 (range 18-84) years. Of 86 patients, 33 (38.4%) had unilateral and 53 (61.6%) had bilateral maxillary sinus hypoplasia. Of 139 maxillary sinuses totally included, 73 (52.5%) were type 1, 51 (36.7%) were type 2 and 15 (10.8%) were type 3 hypoplastic maxillary sinuses. Of 332 frontal sinuses totally included, 25 (7.5%) were aplastic, 32 (9.6%) were hypoplastic, 172 (51.9%) were medium-sized, and 103 (31%) were hyperplastic. Of 86 patients with a hypoplastic maxillary sinus at least on one side, 29 (33.7%) had a hypoplastic and/or aplastic frontal sinus, while 10 (12.5%) had a hypoplastic and/or aplastic frontal sinus at least on one side in control group. Incidence of frontal sinus hypoplasia and/or aplasia was significantly higher in patients with maxillary sinus hypoplasia compared to the patients with bilaterally normal maxillary sinuses (χ2 = 10.384, P = 0.001). Maxillary sinus hypoplasia has a significantly higher coexistence with frontal sinus hypoplasia. This study may have an implication for anatomical studies about the development of the paranasal sinuses and paranasal sinus surgery as well as further morphological studies.

[Original three-dimensional reconstruction of a case of metopism associated with a unilateral complete absence of the left frontal sinus: Clinical interest and review of the literature]. / Représentation tridimensionnelle originale d'un cas de métopisme associé à une agénésie unilatérale complète du sinus frontal gauche : intérêt clinique et revue de la littérature.

Metopism (complete persistence of the metopic suture in adults) is a rare but not exceptional variation of the calvaria. Hypoplasia or aplasia of the frontal sinus may be associated without evident correlation. Nevertheless, a misdiagnosis of these variations may have clinical consequences, especially in a traumatic context. The aim of this paper was to report a case of metopism associated with a unilateral aplasia of the left frontal sinus, originally illustrated with 3D image fusion volume rendering reconstructions.

Prevalence of agenesis of frontal sinus in human skulls with metopism.

BACKGROUND: The frontal bone is an anatomical structure of the skull separated by the metopic suture in the childhood. The scientific literature indicates that metopic suture consolidates with closure in the early stages of life. Metopism is the term used to describe a metopic suture that persists up to the adulthood. Persistent metopic suture is associated potentially with the agenesis of the frontal sinus. AIM: To investigate the prevalence of absent frontal sinuses in dry skulls with metopism. MATERIALS AND METHODS: The present study was performed after the approval of the local Committee of Ethics in Research. The sample consisted of dry skulls (n=245), aging between 17 and 50 years old, of the Forensic Medical Institute of Goiânia, Brazil. The skulls underwent anthropological exam in the search for metopism. Radiographic exam was performed in the skulls with metopism to verify the presence or absence of the frontal sinus. The radiographic assessment was performed with a Mobile DaRt Evolution device (Shimadzu, Kyoto, Japan) with protocol set in 64 kV and 16 mA). RESULTS: From the 245 dry skulls, 17 presented metopism. The length of the metopic suture in the skulls, considering the distances between nasio and bregma craniometric landmarks, ranged between 114 mm and 137 mm. Radiographic exams were performed on 16 skulls (one skull was not analysed radiographically because of extensive destruction). Only one skull (6.25%) had the frontal sinus absent. Besides the agenesis, the present study also found four (12.5%) skulls with aplasia and eight (25.0%) hyperplasia of the frontal sinus in dry skulls with metopism. CONCLUSION: The present study found a low prevalence rate of the agenesis of frontal sinuses in dry skulls with metopism.

The Role of Conservative Management in Pneumosinus Dilatans Frontalis With Minimal Bony Deformity.

The authors describe the conservative management of 2 rare patients of uncomplicated pneumosinus dilatans of the frontal sinus with minimal bossing of the forehead. Regular nasal hygiene in combination with topical corticosteroids was administered with following complete resolution symptoms.

Pneumatization of crista galli in pre-adult and adult stages / Neumatización de la crista galli en etapas pre adultas y adultas

The sinonasal region in humans is one of the regions that commonly shows anatomical variations. These variations can be easily diagnosed by paranasal CT evaluation. One of these variations is Crista galli pneumatization. In recent years, there have been opinions supporting the hypothesis that pneumatization originates from the frontal sinus. In this study, we planned to evaluate whether the presence of Crista galli pneumatization varied in pre-adult and adult periods. In this retrospectively designed study, 218 coronal paranasal CT images collected between 2012 and 2013 were evaluated. Patients were divided into two groups according to age under or over 18 years. In the group under the age of 18 (97 cases), pneumatization was detected in 2.1 % of samples, while in the group over the age of 18 (121 cases), crista galli pneumatization was observed in 15.7 % of samples. According to these results, crista galli pneumatization was found to increase in adulthood. Considering that the frontal sinus is in a rudimentary state at birth, it is radiographically detected first at 6 years of age, and reaches its main size in puberty, this increase in pneumatization runs parallel to the development of the frontal sinus. Consequently, this supports the opinion that crista galli pneumatization originates from the frontal sinus.

La región nasosinusal en los seres humanos con frecuencia muestran variaciones anatómicas. Estas variaciones se pueden diagnosticar fácilmente mediante la evaluación por tomografía computadorizada (TC) de los senos paranasales. Una de estas variaciones es la neumatización de la Crista galli. En los últimos años, se ha apoyado la hipótesis de que ésta neumatización se origina en el seno frontal. En este estudio fue evaluada la presencia de neumatización de la Crista galli y su posible variación en los períodos pre-adultos y adultos. Se realizó un estudio retrospectivo donde se evaluaron 218 imágenes de TC coronal de senos paranasales, recogidas entre 2012 y 2013. Los pacientes fueron divididos en dos grupos según la edad, menores o mayores de 18 años. En el grupo de menores de 18 años (97 casos), se detectó neumatización en el 2,1 % de las muestras, mientras que en el grupo de mayores de 18 (121 casos), se observó neumatización de la Crista galli en el 15,7 % de las muestras. De acuerdo con estos resultados, la neumatización de la Crista galli aumenta en la edad adulta. Teniendo en cuenta que el seno frontal se encuentra en un estado rudimentario en el nacimiento, se detecta radiográficamente a los 6 años de edad alcanzando su tamaño principal en la pubertad; este aumento de la neumatización es paralelo al desarrollo del seno frontal. En consecuencia, esto apoya la opinión de que la neumatización de la Crista galli se origina en el seno frontal.

Extension of the frontal sinus into the roof of the optic canal: a cadaveric case report.

This case reports a bilateral asymmetrical posterior extension of the frontal sinuses into the orbital roof with an unusual expansion into the roof of the optic canal in a 55-year-old male cadaver. The posterior extensions of the sinus were lined by mucoperiosteum and were separated from the underlying orbital contents and optic nerve by a thin plate of bone. This knowledge of an unusual anatomic variation of the frontal sinus may help understand better the ocular and intracranial complications associated with frontal sinus pathologies.

Hidden unilateral aplasia of the frontal sinus: a radioanatomic study.

BACKGROUND: Hidden unilateral frontal sinus aplasia is the absence of 1 frontal sinus with increased pneumatization of contralateral sinus toward the aplastic side. It may give the false impression of the presence of 2 separate frontal sinuses, creating potential for complications during the surgery. The aim of this study was to evaluate the prevalence and morphology of this anatomical variation using multiplanar reconstruction of computed tomography (CT) results. METHODS: A total of 305 CT examinations were analyzed. Hidden unilateral frontal sinus aplasia was defined as lack of pneumatization of 1 frontal sinus beyond the level of the orbital roof, with increased pneumatization of the contralateral sinus, extending to the sagittal plane, crossing the lamina papyracea on the side of the aplastic sinus. RESULTS: Eleven patients (3.6%) with hidden unilateral frontal sinus aplasia were identified, 5 on the left and 6 on the right side, in 5 female and 6 male patients. Twenty-four (7.8%) patients with "regular" frontal sinus aplasia (without hyperplastic contralateral frontal sinus) were found, 4 with bilateral aplasia and 20 with unilateral aplasia. CONCLUSION: Hidden unilateral aplasia of the frontal sinus is a relatively uncommon anatomical variation. Its presence should be considered during routine preoperative CT evaluation because it poses the risk of intraoperative complications.

Facial asymmetry with enlarged frontal sinus and hyperplasia of the cranial, nasal, and mandible bones.

The conditions of facial asymmetry are caused by congenital or acquired diseases, and several unclassifiable syndromes with unknown etiologies exist. In this report, a case of facial asymmetry with enlarged frontal sinus and hyperplasia of the frontal cranial bone and nasal bone is presented. Although the etiology of the facial malformation was clear, it was thought that the cause of the enlarged frontal sinus was related to the unidentified bony hyperplasia and facial asymmetry related to hemimandibular hyperplasia.

Aesthetic correction of hypertrophic frontal sinus with beveled osteotomy.

The authors performed aesthetic correction of hypertrophic frontal sinus in 3 patients with protruded supraorbital region by using beveled osteotomy. Under general anesthesia, a bicoronal incision was performed followed by dissection through the subgaleal plane to the supraorbital ridge. Subsequently, the anterior wall of the frontal sinus was sectioned with a reciprocating saw and an osteotome by using the beveled osteotomy technique. Beveled osteotomy is a technique applied during sectioning of the anterior wall of the frontal sinus whereby the upper portion of the sinus remains intact and the lower portion of the sinus is changed. The technique used by the authors differed from the conventional method in that the existing shape of the outer wall of the frontal sinus was preserved when osteotomy was performed. This technique therefore preserves a more natural contour of the forehead and is advantageous in that it does not require additional interventions.

Frontal sinus septations predict the presence of supraorbital ethmoid cells.

OBJECTIVES/HYPOTHESIS: This study is undertaken to determine if the presence or absence of multiseptated frontal sinuses is associated with the presence or absence of supraorbital ethmoid cells (SOECs). STUDY DESIGN: Analysis of prospectively collected data. METHODS: Sixty consecutive patients with chronic rhinosinusitis were identified from a prospectively collected database at a tertiary-referral institution as having full-sinus computed tomography (CT) scans. Preoperative or initial CT scans of the sinuses were reviewed, specifically identifying the presence or absence of supraorbital ethmoid air cells (SOECS) and frontal sinus multiseptated sections on coronal imaging. Statistical analysis was performed using the chi-squared test to evaluate any association between the two structural entities. RESULTS: Sixty total patients were identified, for a total of 120 sides. Of the 61 sides with frontal septations, 43 (70%) had SOECs present and 18 (30%) did not. Of the 59 sides without frontal sinus septations, 13 (22%) had SOECs present and 46 (78%) did not (chi squared = 28.3; P = 0.0000001). The difference in the presence of supraorbital ethmoid cells between whites and blacks is also statistically significant (chi squared = 4.23; P = 0.040). CONCLUSION: The presence of frontal sinus septations appears to be significantly associated with and predictive of the presence of supraorbital ethmoid cells. Thus, identifying frontal sinus septations on sinus CT is implicated with more complex anatomy of the frontal recess.