Temporal bone pneumatization: A scoping review on the growth and size of mastoid air cell system with age

Analysis of growth pattern of temporal bone pneumatization using 3D reconstructed computed tomography

BACKGROUND

Temporal bone pneumatization (TBP) is influenced by age, sex, and race, and it seems to progress rapidly to puberty. However, the extent of TBP in childhood remains unclear.

PURPOSE

To investigate the progression of TBP in children aged 1-18 years via three-dimensional (3D) reconstruction of high-resolution computed tomography (CT) images.

MATERIAL AND METHODS

A total of 432 temporal bones of 216 individuals aged 1-18 years with well-pneumatized mastoid antra on both sides were included in this retrospective work. We created 18 age groups, each with six boys and six girls. Surface rendering of air density was performed using -290 HU to obtain TBP. Statistical analysis employed SPSS version 24.0 software (IBM Corp., Armonk, NY, USA).

RESULTS

The linear regression equations that considered age and volume for all cases (ya), male (ym) and female (yf) were ya = 384.42x + 1790.40, R2 = 0.425; ym = 431.54x + 1440.9, R2 = 0.501; and yf = 337.26 x + 2140.5, R2 = 0.355. Both male and female individuals showed an increase in the average value of pneumatization until the age of 17, and the values ​​of pneumatization at specific ages for boys and girls showed differences. The mean male and female TBP levels differed significantly at 3, 11, and 18 years of age (P < 0.05).

CONCLUSION

TBP in boys was greater than that of girls at adolescence. It was possible to identify the specific periods of significant variation in the degree of pneumatization of temporal bone.

Facial Nerve Pathology in Children

Facial nerve pathology in children has devastating functional and psychosocial consequences. Facial palsy occurs less commonly in children than adults with a greater proportion caused by congenital causes. Most pediatric patients have normal life expectancy and few comorbidities and dynamic restoration of facial expression is prioritized. This article will focus on the unique aspects of care for facial palsy in the pediatric population.

Changes in paranasal sinus volumes, temporal bone pneumatization, internal acoustic canal and olfactory cleft dimensions over the centuries: a comparison of skulls from different epochs in Anatolia

OBJECTIVES

Investigating changes in temporal bone pneumatization (TBP) and paranasal sinus volumes (PSV) across different eras may help understanding not only changes in skull anatomy but also pathophysiology of chronic otitis media and sinusitis, respectively, which are common health problems.

METHODS

Eight skulls from the second century AD, 20 skulls were from the 10th-11th centuries AD, 20 skulls from the 16th-19th centuries AD, and 60 contemporary skulls were included in this cross-sectional observational study. Using computerized tomography (CT) scans, the PSV were calculated by multiplying the height, width, and antero-posterior distance of the sinuses. TBP was divided into three types. Internal acoustic canal (IAC) length and width, and olfactory cleft (OC) width were measured.

RESULTS

No statistically significant differences were found between the paranasal sinus (frontal, maxillary, and sphenoid) volumes between the groups. However, TBP decreased statistically significantly over time on both sides of the skulls (p = 0.001). The contemporary IAC and OC measures were found to be significantly lower on both sides compared to the skulls from the other three eras (p < 0.001 for both).

CONCLUSIONS

Although no significant change was observed in PSV, decreases were evident in TBP, OC width and IAC length and width over time. It appears a fair inference that changes in size of OC and IAC might be another indication of the fact that olfaction and hearing were more vital for survival in old eras. Since we do not know incidence of chronic ear problems in old eras, we cannot speculate outcome of increased TBP in terms of developing chronic ear diseases. On the contrary, increased TBP was likely to play a protective role in traumas in old ears. Additionally, the environmental influences may be crucial role in the development of paranasal sinuses.

The Role of Temporal Bone Pneumatization on Fracture Line and Involved Cranial Structures

OBJECTIVE

Temporal bone pneumatization (TBP) is speculated to serve as a shock absorber in temporal bone fractures (TBF), directing the fracture line away from vital structures. This study correlates TBP extent with TBF patterns and preservations of vital TB structures.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary referral medical center.

METHODS

All TBF patients referred to a single tertiary center 2017 to 2023 were evaluated. A pneumatization index score for each of their TBs was derived by counting automated-voxel density in a 0 to 100 scale. Results were correlated to the TBF type and the violated structure(s). The ossification index was compared to previously detailed qualitative classification systems of TBP.

RESULTS

One hundred and forty-five patients were enrolled (mean age 43 ± 17 years). Kinematics were motor vehicle accidents (46%), scooter (15%), bicycle (14%), falls (13%), and assaults (8%). The mastoid ossification index we used showed a strong correlation to all qualitative classification systems (sigmoid = 0.829; labyrinthine = 0.849; carotis = 0.863, infralabyrinthine = 0.869, all P < .001). The pneumatization index strongly correlated with capsule-violating TBFs, with a mean of 44 ± 23 for otic capsule-sparing TBF and 61 ± 20 for otic capsule-violating (OCV) TBF (P < .001). The facial nerve was violated in 30 patients. Facial canal (FC) involvement was not correlated to the ossification index: it was 49 ± 23 for FC-sparing and 44 ± 23 for FC-violating (P = .620).

CONCLUSION

TBP serves as a protective mechanism against OCV TBF. The more pneumatized the TB, the less likely the otic capsule will be violated in the event of a TBF with the exception of the carotid and FCs. TBP index is in strong agreement with qualitative TBP classification systems.

A novel method for evaluating mastoid defect regrowth after cochlear implantation

This retrospective study examined mastoid defects resulting from cochlear implant (CI) surgery and their potential for spontaneous regrowth across different age groups. Spontaneous closure of mastoid defects has been observed in certain CI patients during revision surgery or through post-operative temporal bone computer tomography (TB-CT). The analysis encompassed 123 CI recipients, comprising 81.3% children and 18.7% adults, who underwent post-operative TB-CT scans. Using image adjustment software, the study measured mastoid defect areas and found a significant reduction in children's defects between the initial and subsequent scans. Notably, mastoid defect areas differed significantly between children and adults at both time points. Furthermore, the analysis revealed significant correlations between mastoid defect areas and the age at implantation as well as the time elapsed since the CI surgery and the first CT scan. This study provides valuable insights for evaluating CI patients scheduled for revision surgery by assessing potential surgical challenges and duration. Furthermore, it may have a pivotal role in evaluating patients who experience postauricular swelling subsequent to CI surgery.

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.

Quantification of Mastoid Air Cells and Opacification of the Middle Ear in Primary Ciliary Dyskinesia

OBJECTIVE

To evaluate pneumatization and opacification of the temporal bone on computed tomography (CT) images in patients with primary ciliary dyskinesia (PCD).

STUDY DESIGN

Retrospective case-control study.

SETTING

Tertiary referral center.

PATIENTS

Fifteen patients with PCD (30 ears) and 45 age-matched individuals without PCD (90 ears) as controls.

INTERVENTION

Diagnostic only.

MAIN OUTCOME MEASURES

Quantification of mastoid air cells in the PCD and control groups and comparison between them. Degree of middle ear opacification on CT images of the temporal bone in the PCD group.

RESULTS

The volume of the mastoid air cells was 30% smaller in the PCD group than in the control group ( p < 0.05). The suppression ratio, which is defined to indicate how much the average volume of mastoid air cells in the PCD group is suppressed relative to the control group, was 64% lower in the PCD group ( p < 0.05). Opacification was noted in 47% of the mastoid air cells and 63% of the tympanic cavity on CT images of the temporal bone in the PCD group, which were significantly higher frequencies than in the control group (1.1% and 1.1%, respectively).

CONCLUSIONS

Compared with individuals without PCD, those with PCD showed a significantly smaller volume of mastoid air cells and a significantly higher frequency of opacification of mastoid air cells and tympanic cavity on temporal bone CT. Otitis media raises suspicion for PCD, and the otological manifestations of PCD reported here could help to narrow the differential diagnosis and facilitate early treatment.

The association between high jugular bulb and mastoid pneumatization in adults

Purpose

The purpose of this study was to analyze the relationship between the degree of high jugular bulb (HJB) and mastoid pneumatization using high-resolution computed tomography (HRCT).

Methods

Between April 2019 and June 2022, HRCT of the temporal bone was retrospectively analyzed in 1,025 patients. By excluding the other coexistent pathologies, 113 patients with HJBs were recruited for the study. The degree of the HJBs were defined as follows: Grade I, JB situated between inferior annulus of tympanic membrane and cochlear basal turn (CBT). Grade II, JB situated between CBT and lateral semicircular canal (LSC). Grade III, JB situated above LSC. The volume of mastoid pneumatization was based on HRCT images using a 3D reconstruction.

Results

There were 32 male and 81 female subjects (mean age, 41.2 ± 14.0 years; age range, 18-80 years). The male group included 16 Grade I, 28 Grade II and 6 Group III HJB subjects. The female group included 38 Grade I, 62 Grade II and 31 Group III HJB cases. In the different groups of HJB, the mastoid cell volume differences were also not statistically significant (p = 0.165). In the classification, Grade II was most common (90/181, 49.7%).

Conclusion

This study found no correlation between mastoid air cell volume and HJB, suggesting that HJB may not affect the mastoid air cell development and disease occurrence. These data must be considered exploratory, requiring more extensive cross-sectional studies.

Communication between the temporomandibular joint articular space and the extradural space in patients with temporal bone pneumatization: implications for temporomandibular joint surgery

The pneumatization of the articular portion of the temporal bone is an anatomical variant that can modify the barrier between the articular space and the middle cranial fossa. Thus, this study aimed to identify the presence and degree of pneumatization, as well as the existence of pneumatic cell dehiscence towards the extradural or articular space determining whether it could lead to direct communication between the articular and extradural spaces. Hence, One-hundred skull computed tomography images were selected. The presence and extension of pneumatization were classified according to scores 0, 1, 2, and 3. Dehiscence towards extradural and articular spaces was recorded. In total, 200 TMJ from 100 patients were assessed and 40.5% of pneumatization cases were observed. The most prevalent score was 0 (restricted to the mastoid process), while the least prevalent score was 3 (extending beyond the crest of articular eminence). Dehiscence of the pneumatic cells towards the extradural space is more common than towards the articular space. One complete communication between the extradural and articular spaces was observed. Considering the results, it was concluded that to avoid neurological and ontological complications, awareness of the potential anatomical communications between articular and extradural spaces, particularly in patients with extensive pneumatisation, is necessary.

The Age-Related Growth of Mastoid Air Cells in Infancy: A Retrospective Cross-Sectional Study

OBJECTIVES

To investigate the normal growth and development of mastoid pneumatization volume from 5 to 12 months for pediatric otosurgeons.

STUDY DESIGN

Retrospective chart review.

SETTING

A tertiary referral center.

PATIENTS

This study evaluated age-dependent changes in mastoid air cell volume in 94 (188 ears) patients aged 5 to 12 months without a history of middle ear disease.

MAIN OUTCOME MEASURES

Volume reconstruction was based on high-resolution computed tomography images using a three-dimensional reconstruction that is considered normal by radiologists. One-way analysis of variance and linear regression were used to determine the relationship between the volume and age in male and female subjects.

RESULTS

Forty-eight scans were from male and 46 from female patients. In the age group from 5 to 12 months, the mastoid pneumatization was independent of age ( p > 0.05). There were no significant volume differences found between the age groups. Neither male/female nor right/left significant differences were observed in relation to the algebraic data of the mastoid air cells volume ( p > 0.05).

CONCLUSIONS

Based on this analytic study, we are the first to use three-dimensional volume quantification based on high-resolution computed tomography in such large samples of early infancy. Because of its potential role as a susceptibility factor for otitis media and other otologic problems, it is important to describe the growth and development of mastoid pneumatization. More extensive clinical studies are needed to give a comprehensive insight into the air cell volume across age groups in different populations.

The cranial capacity of the Saudi population measured using 3D computed tomography scans

OBJECTIVES

To measure the cranial capacity of members of the Saudi adult population across ages and genders.

METHODS

This was a retrospective cross-sectional study that used 488 Computed Tomography (CT) scans of heads (of which 275 males) to measure cranial volume. The CT slices 0.625 mm thick were uploaded using the freely available software "3D-Slicer", which then reconstructed the images and built a 3D module.

RESULTS

The mean (±SD) cranial capacity of the males was 1481.6 (±110) cm3 (range: 1241-1723 cm3), whereas the cranial capacity of the females was 1375.4 (±104) cm3 (range: 1203-1678 cm3). This study showed that the males had a mean cranial capacity that was 7% greater than that of the females in this study. The average cranial capacity of the males between the ages of 31 and 40 years was statistically significantly larger to that of the males aged 61-80 (p<0.05).

CONCLUSION

This study demonstrated that the average cranial capacity of the males was larger than that of the females. These study results can help to determine the normal cranial capacity of adults in Saudi Arabia. Further work should be carried out to aid in establishing reference data for the Saudi population.

An inter-observer assessment of mastoid pneumatization and degree classification using sigmoid sinus: comparing two levels of temporal bone computed tomograms

BACKGROUND

The degree of mastoid pneumatization of the temporal bone (TB) has been implicated in the pathogenesis of TB diseases and surgical implications, and planning of a few otologic surgeries. However, there is lack of consensus in the classification of the degree of pneumatization. This study aimed to suggest a simple, quick, and less-burden classification system for assessing and rating the degree of pneumatization by comparing two levels of TB computed tomographs (CTs) using the SS as a reference in an inter-observer assessment among otologists.

METHODS

This was a randomized pilot survey among otologists. A questionnaire consisting of different axial CTs of TB taken at two levels: the level of malleoincudal junction (MIJ) and the level of lateral semicircular canal (LSCC), with different pneumatization patterns, was used to assess participants' impressions of the degree of pneumatization. The terms "hypo-," "moderate," "good," and "hyper-" pneumatization were listed as options to rate their impressions on the degree of mastoid pneumatization of the TB images using the SS as a reference structure. Likert scale was used to assess their level of agreement or disagreement with using SS as a reference in evaluating mastoid pneumatization.

RESULTS

Participants who correctly rated images taken at the level of LSCC according to their respective degree of pneumatization were significantly higher (p < 0.05) regardless of their year of experience compared to those that correctly rated corresponding images taken at the level of MIJ. A 76% positivity in their level of agreement with the use of sigmoid sinus in evaluating mastoid pneumatization was observed on the Likert-scale chart.

CONCLUSION

Findings from this study suggest that evaluating air cells around the SS at the level of LSCC on CTs could be easier in assessing and classifying the degree of mastoid pneumatization.

Pneumatization Pattern and Status of the Mastoid Antrum in Chronic Otitis Media: A Review

Chronic otitis media is generally more prevalent in individuals with a weakly pneumatized temporal bone, whereas acute otitis media has a propensity for pneumatized temporal bone. Antimicrobial drugs are thought to have influenced the incidence and progression of middle ear infections. The mastoid air cell system, a part of the middle ear cleft, has recently been recognized as a crucial factor in the genesis, behaviour, course, and outcome of middle ear inflammatory conditions. Epithelium infiltrates the growing bone and produces epithelium-lined air cell chambers, a process known as pneumatization.

Conventional temporal bone radiography, i.e. X-ray mastoid, has not kept up with recent otology breakthroughs. Detailed visualization of the aural structures has advanced significantly with the introduction of high-resolution computed tomography (HRCT). HRCT has a clear edge in the assessment of the temporal bone, especially when thin-section, high-resolution methods are used, resulting in a more precise description of the pneumatization pattern and the anatomical extent of middle ear pathology.

Our results of the review indicated that persistent inflammation of the middle ear in children inhibits pneumatization of the temporal bone. Due to its potential to exert a greater negative middle ear pressure, the middle ear volume is insufficient to generate a retraction pocket; thus, the size and state of the antrum is also a significant factor in the establishment of a COM-like retraction pocket in inactive squamosal disease. Numerous factors, including the number of patients, regional, genetic, ethnic and hereditary characteristics, as well as the cellularity of the mastoid, which is impacted by a multitude of factors, may account for the variable reports and inter-study variation in this regard.