Hidden unilateral agenesis of the frontal sinus: human cadaver study of a potential surgical pitfall

Three-dimensional reconstruction of King Henri IV's paranasal sinuses and mastoid cells

PURPOSE

The preserved head of King Henri IV of France (life 1553-1610, reign 1589-1610) has survived to the present day thanks to high-quality embalming and favorable conservation conditions. The aim of this study was to examine Henry IV's upper resonant cavities and mastoids using an original and innovative forensic three-dimensional segmentation method.

METHODS

The paranasal sinuses and mastoid cells of King Henri IV of France were studied by cross-referencing available biographical information with clinical and flexible endoscopic examination and computed tomography (CT-scan) imaging. The paranasal sinuses and mastoid cells were delineated and their volumes were assessed using ITK-SNAP 4.0 software (open-source). Graphical representations were created using Fusion 360® (Autodesk Inc., San Rafael, CA, USA) and MeshMixer® (Autodesk Inc., San Rafael, CA, USA).

RESULTS

Paranasal sinus tomodensitometry revealed abnormalities in shape and number. Henri IV of France suffered from sinus aplasia. Neither the left sphenoid nor left frontal sinus contrasted sharply, and a remarkable pneumatization of the right clinoid processes extended throughout the height of the right pterygoid process. The total volumes of Henri IV's mastoid air-cells were estimated at 27 and 26 mL, respectively, for the right and left sides, exceeding the normal mean and the maximum of modern subjects by a wide margin. No sign of chronic ear or sinus condition was found.

CONCLUSIONS

An innovative method has been developed in forensic medicine to establish hypotheses about the growth and respiratory conditions of the face.

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.

Distribution of frontal sinus pattern amongst Malaysian population: a skull radiograph study

Frontal sinus has unique anatomical features that are distinct to every population. However, the distribution of frontal sinus patterns has yet to be explored in the Malaysian population. This study aimed to describe the distribution of frontal sinus patterns among adult Malaysians. 409 adult Malaysian posteroanterior skull radiographs, consisting of 200 males and 209 females of Malay, Chinese, and Indian races aged between 20–69 years old, were included in the study. The frontal sinus patterns were classified according to total and percentage of presence or absence of frontal sinus, symmetry or asymmetrical (right or left dominant), unilateral absence (right or left), bilateral absence, and lobulation. The findings showed that bilateral presence of frontal sinus is common, in 95.4% of individuals and bilateral absence was noted in 2.7% individuals. Unilateral absence was found in 2.0% of individuals. Asymmetrical frontal sinus was observed in 54.5% of population meanwhile 40.8% showed symmetrical frontal sinus. The majority of individuals, regardless of sex, race, and age, possessed 1 to 3 lobes on both sides of the frontal sinus. The findings suggest that the frontal sinus is highly asymmetric, and the absence of the frontal sinus is rare. This morphological variation provides an insight into the landmarking placement for measurement during forensic application and assists neurosurgeons in surgical procedure to avoid breaching of the frontal sinus.

The Relation Between the Metopic Suture Persistence and Frontal Sinus Volume and Olfactory Fossa Depth: A Reliability Study with Semiautomatic Volume Measurement

Objective:

This study aims to investigate the relationship of the persistence of metopic suture (PMS), frontal sinus volume (FSV), and olfactory fossa depth (OFD).

Methods:

Tomography scans of 1,603 patients aged 18-65 years were evaluated for the presence of PMS. In the study, 74 PMS cases and 74 controls were included. The appearance of each individual’s frontal sinus was classified as aplasia, hypoplasia, or normal. Two observers independently measured the lateral lamella length (LLL), OFD, and FSV. Interobserver agreement was evaluated with the intraclass correlation coefficient (ICC) and Cohen’s kappa coefficient (κ).

Results:

The prevalence of PMS was found to be 4.99% [95% confidence interval (CI): 4.03-6.17]. The PMS group had five times higher hypoplasia/aplasia than the controls (52.70%, 95% CI: 41.48-63.66 and 10.81%, 95% CI: 5.58-19.91, respectively; p<0.001). An “almost perfect” agreement was detected among observers for the frontal sinus appearance classification: κ=0.807, p<0.001. The ICC of continuous measurements for OFD, LLL, and FSV, respectively, presented “excellent” reliability: 0.956, 0.958, and 0.981, with p<0.001 for each. LLL was shorter, OFD was shallower, and FSV was smaller in the PMS group than the control group (p<0.001). There was a moderate positive correlation between OFD, LLL, and FSV (r=0.306, r=0.302).

Conclusions:

This study interprets that the presence of PMS is related frontal sinus development and volume. With PMS, a smaller FS, shorter lateral lamella, and shallower olfactory fossa may be expected.

Frequency of the frontal sinus aplasia among Saudi Arabian population. A single-center retrospective case review

OBJECTIVES

To assess the frequency of frontal sinus aplasia using computed tomography (CT) of the paranasal sinus among Saudi Arabian population.

METHODS

A retrospective case review of medical records from January 2019 to December 2019 in the Otorhinolaryngology Department, King Abdulaziz University, Riyadh, Saudi Arabia.

RESULTS

A total of 449 cases were reviewed. The incidence of bilateral frontal sinus aplasia was 3.3%. The incidence of right sinus agenesis was 5.12% and left was 1.33%. The mean age of reviewed patients was 39.15 years.

CONCLUSION

The frequency of frontal sinus aplasia is low; however, this must be considered before surgical operations related to the sinuses.

Prevalence of Frontal Sinus Aplasia in Jordanian Individuals

Our paper aims to investigate the prevalence of frontal sinus aplasia among Jordanian individuals and compare it with values from different populations. Retrospectively, the study was done for 167 of the paranasal sinuses coronal tomography (CT) for patients who attended the clinic from January 2019 to August 2019 in King Abdullah University Hospital Irbid, Jordan. The authors analyzed the multiplanar CT scans to perform our work. The authors excluded the following images from our study: patients younger than 18 years old, patients with history of skull base trauma that impaired visualization of the frontal sinus, and images with fibro-osseous lesions that impaired the visualization of the frontal sinus. The prevalence of bilateral frontal sinus aplasia is 4.2% among Jordanian individuals and 6.6% is the prevalence of unilateral frontal sinus aplasia. Both values are consistent with average values among different populations. Moreover, we noticed the higher prevalence in both the bilateral and unilateral frontal sinus aplasia in males compared to females. The prevalence of frontal sinus aplasia among Jordanian individuals is almost within the same values among different populations. These numbers regarding the bilateral and unilateral frontal sinus aplasia is crucial to push the surgeon to evaluate CT of the paranasal sinuses preoperatively and focus on the presence of frontal sinuses on CT images to prevent unwanted complications during sinus surgeries.

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.

Digital radiomorphometric analysis of the frontal sinus and assessment of the relation between persistent metopic suture and frontal sinus development

OBJECTIVES

This study aimed to establish the frequency of the frontal sinus (FS) aplasia, to compare metopic and nonmetopic series and thus to assess the relationship between the preservation of metopic suture and FS development.

MATERIALS AND METHODS

FSs were investigated in 230 dry skulls of adult males distributed into control (137) and metopic (93) series. They were visualized through industrial digital radiography.

RESULTS

In the control series, the FS aplasia was observed in 12.41% of the skulls, and it was mostly unilateral (8.76%) than bilateral (3.65%). The left-sided aplasia (5.11%) slightly prevailed over the right-sided one (3.65%). In the metopic series, the aplasia was observed with a frequency of 19.35%, and the bilateral aplasia (7.53%) was rarer that the unilateral one (11.83%), while the right-sided aplasia was clearly predominant (9.68%) compared to the left-sided one (2.15%).

DISCUSSION

The significant differences between both series showed a tendency for the persistence of metopic suture to be frequently related with FS underdevelopment in the vertical plate of the frontal bone, but in cases of pneumatization, it was preferentially on the left side. Taking into account that the cranial hypertension leads to suture diastasis and hinders development of the FS, it could be suggested that persistence of the metopic suture along with underdevelopment of the FS in nonsyndromic adults could be an expression of an elevated intracranial pressure during early development as an after-effect of certain condition.

The Effect of Nasal Septal Deviation on Frontal and Maxillary Sinus Volumes and Development of Sinusitis

The purpose of this study was to determine the possible role of nasal septal deviation on volume of maxillary and frontal sinuses. Between February 2011 and October 2013, paranasal sinus computed tomography (CT) findings of 732 patients (410 males, 322 females) who were admitted to Ear Nose and Throat Department of Kayseri Research and Training Hospital were retrospectively analyzed. By excluding the other coexistent sinonasal pathologies, 83 consecutive patients with nasal septal deviations were included in the study. The volume of each maxillary and frontal sinus (ipsi- and contralateral to the deviation side) was also calculated using the computer program. There was no statistically significant difference between ipsilateral and contralateral maxillary sinus volumes in group 1 and group 3 (P > 0.05). There was a statistically significant difference between ipsilateral and contralateral maxillary sinus volumes in group 2 (P < 0.05). There was no statistically significant difference between ipsilateral and contralateral frontal sinus volumes in group 1, group 2, and group 3 (P > 0.05). Moderate septal deviation significantly affects the volume of maxillary sinus. Mild and severe septal deviation does not significantly affect the volume of maxillary sinus. Effect of septal deviation on frontal sinus volume was not detected. The probability to encounter maxillary and frontal sinusitis ipsilateral to the all septum deviation groups was significantly increased in both right- and left-sided subjects.

The classification of frontal sinus pneumatization patterns by CT-based volumetry

PURPOSE

We aimed to define the classification of frontal sinus pneumatization patterns according to three-dimensional volume measurements.

METHODS

Datasets of 148 sides of 74 dry skulls were generated by the computerized tomography-based volumetry to measure frontal sinus volumes. The cutoff points for frontal sinus hypoplasia and hyperplasia were tested by ROC curve analysis and the validity of the diagnostic points was measured.

RESULTS

The overall frequencies were 4.1, 14.2, 37.2 and 44.5 % for frontal sinus aplasia, hypoplasia, medium size and hyperplasia, respectively. The aplasia was bilateral in all three skulls. Hypoplasia was seen 76 % at the right side and hyperplasia was seen 56 % at the left side. The cutoff points for diagnosing frontal sinus hypoplasia and hyperplasia were '1131.25 mm(3)' (95.2 % sensitivity and 100 % specificity) and '3328.50 mm(3)' (88 % sensitivity and 86 % specificity), respectively.

CONCLUSIONS

The findings provided in the present study, which define frontal sinus pneumatization patterns by CT-based volumetry, proved that two opposite sides of the frontal sinuses are asymmetric and three-dimensional classification should be developed by CT-based volumetry, because two-dimensional evaluations lack depth measurement.

Frontal sinus parameters in computed tomography and sex determination

The frontal sinus is a sturdy part of the skull that is likely to be retrieved for forensic investigations. We evaluated frontal sinus parameters in paranasal sinus computed tomography (CT) images for sex determination. The study was conducted on 200 normal paranasal sinus CT images of 100 men and 100 women of Persian origin. We categorized the studied population into three age groups of 20-34, 35-49 and ⩾ 50 years. The number of partial septa in the right frontal sinus and the maximum height and width were significantly different between the two sexes. The highest precision for sex determination was for the maximum height of the left frontal sinus (61.3%). In the 20-34 years age-group, height and width of the frontal sinus were significantly different between the two sexes and the height of the left sinus had the highest precision (60.8%). In the 35-49 years age-group, right anterior-posterior diameter had a sex determination precision of 52.3%. No frontal sinus parameter reached a statistically significant level for sex determination in the ⩾ 50 years age-group. The number of septa and scallopings were not useful in sex determination. Frontal sinus parameters did not have a high precision in sex determination among Persian adults.

Combined Aplasia of Frontal and Sphenoid Sinuses with Hypoplasia of Ethmoid and Maxillary Sinuses

The paranasal sinuses are air filled spaces. The process of development of paranasal sinuses begins prenatally. The agenesis of paranasal sinuses in an unusual clinical condition and that is mainly confined to the frontal sinus unilaterally. Combined aplasia of multiple sinuses is extremely rare along with hypoplasia of other sinuses. Agenesis of sphenoid sinus is also rare in incidence. We report a case of a 54 years old female, who presented with complains of persistent headache with nasal blockage and found to have combined aplasia of bilateral frontal and sphenoid sinus with hypoplasia of bilateral maxillary and ethmoid sinus with unusual age of presentation. The findings were confirmed on non-contrast computed tomography scan of paranasal sinuses.

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.

Aplasia and agenesis of the frontal sinus in Turkish individuals: a retrospective study using dental volumetric tomography

Agenesis of the paranasal sinuses is an uncommon clinical condition that appears mainly in the frontal (12%) and maxillary (5-6%) sinuses; in some populations, it appears at a higher proportion. This study investigated the prevalence of agenesis of the frontal sinuses using dental volumetric tomography (DVT) in Turkish individuals. The frontal sinuses of 410 patients were examined by DVT scans in the coronal planes for evidence of the absence of the frontal sinuses. A bilateral and unilateral absence of the frontal sinuses was seen in 0.73% and 1.22% of cases, respectively. In one case, both agenesis and aplasia of the frontal sinus was seen (0.24%). The low percentage of frontal sinus agenesis must be considered during pre-surgical planning related to the sinuses. DVT may be used as a diagnostic tool for the examination of frontal sinus aplasia.