Differences in mastoid pneumatization between Asians and Caucasians

BACKGROUND

Anatomical differences of the mastoid pneumatization in Asian and Caucasian patients must be considered when performing the retrosigmoid craniotomy since it may have implications to avoid specific complications such as cerebrospinal fluid infections or fistula.

METHODS

We selected cranial CT scans of 120 Asian and 120 Caucasian patients, who were treated at the Mitsui Memorial Hospital (Japan) and at the Heidelberg University Hospital (Germany). Mastoid pneumatization was classified according to the relationship of the mastoid air cells (MAC) to the sigmoid sinus (Type I - III). The risk of mastoid air cell opening through craniotomy increases from Type I to III. Comparative analyses between gender and ethnicities were performed using the Chi² Test and the independent T-Test and considered significant if p < 0.05.

RESULT

In Caucasians, Type III pneumatization was significantly overrepresented compared to Type II or I, compared to the Asian cohort (Type III:II:I in Caucasians = 60 %:26 %:14 %; in Asians = 28 %:43 %:29 %). Importantly, we found significant differences in pneumatization types between Caucasians and Asians in both gender subgroups (m: Type III 60 % vs 35 %; Type II 30 % vs 36.7 %; Type I 10 % vs 28.3 %, p = 0.008; f: Type III 60 % vs 23.3 %, Type II 21.7 % vs 48.3 %, Type III 18.3 % vs 28.3 %, p < 0.001; Chi² Test).

CONCLUSION

Caucasian patients are more prone to the opening of the mastoid air cells than Asian patients when performing a retrosigmoid craniotomy due to differences in the degree of mastoid pneumatization. This may help to avoid complications such as postoperative infections or cerebrospinal-fluid fistula.

Association study of the pneumatization degree of mastoid air cells and postoperative complications after microvascular decompression in hemifacial spasm

BACKGROUND

This study aimed to analyse the association between the degree of pneumatization of mastoid air cells (MACs) and postoperative complications after microvascular decompression in hemifacial spasm.

METHODS

We retrospectively reviewed 308 patients with hemifacial spasm who underwent surgery at our institute between January 2017 and March 2021. The degree of pneumatization of MACs was classified into four grades (grades 1, 2, 3, and 4) according to method of Han et al. The clinical data of the four grades were analysed and statistically examined.

RESULTS

There were no statistically significant differences between the four grades in terms of the operative time, intraoperative blood loss, and postoperative hospital stay (all, P > 0.05). The incidence of hearing loss was higher in grade 4 MACs (26.56%) than in grades 1 and 2 MACs (5.41% and 2.89%, respectively; P < 0.05). The incidence of facial paralysis was higher in grade 4 MACs (28.13%) than in grades 1 and 2 MACs (5.41% and 9.18%, respectively; P < 0.001). The incidence of intracranial infection was higher in grade 3 MACs (17.65%) than in grade 2 MACs (3.89%) (P < 0.05). All four patients with cerebrospinal fluid leakage belonged to grade 4 MACs. The incidence of cerebrospinal fluid leakage was higher in grade 4 MACs (5.13%) than in grade 2 MACs (P < 0.05).

CONCLUSIONS

This study found that the degree of pneumatization of MACs was closely related to the postoperative complications after MVD surgeries. Well-pneumatized MACs increase the risk of cerebrospinal fluid leakage and intracranial infection. However, insufficient exposure increases the risk of facial paralysis and hearing loss. For patients with well-pneumatized MACs, sufficient surgical exposure is the top priority when locating the bone hole. For those who may have a latent MAC opening, preventive occlusion should be considered.

Comparative study on adhesive otitis media and pars tensa cholesteatoma in children

OBJECTIVE

Recurrent otitis media and persistent otitis media with effusion in early childhood may cause an atelectatic eardrum and adhesive otitis media, which sometimes progress to pars tensa cholesteatoma. When and how children with adhesive otitis media should be operated on remain controversial. Therefore, this study aimed to analyze the clinical characteristics of children with adhesive otitis media and pars tensa cholesteatoma, and to determine the risk factors of progression to cholesteatoma.

METHODS

Seventeen ears of 15 children with adhesive otitis media (adhesive group) and 14 ears of 13 children with pars tensa cholesteatoma (tensa cholesteatoma group) who underwent tympanoplasty were included in this study. We analyzed the following clinical characteristics of children in both groups: medical and life history, associated diseases, sites of the adhesion, and development and aeration of mastoid air cells as shown by temporal bone computed tomography.

RESULTS

Most of the children in both groups had a history of recurrent otitis media and/or persistent otitis media with effusion. They showed a male predominance and a frequent association of allergic rhinitis. The number of ears showing undeveloped mastoid air cells in the tensa cholesteatoma group was significantly larger than that in the adhesive otitis media group (P=0.0068). A lack of aeration of the middle ear, including the eustachian tube, was more frequently found in ears with pars tensa cholesteatoma than in ears with adhesive otitis media (P=0.0012). Using multivariate logistic regression, the presence of otorrhea (odds ratio [OR], 14.847; 95% confidence interval [CI], 0.834-264.184), total adhesion (OR, 28.550; 95% CI, 0.962-847.508), and undeveloped mastoid air cells (OR, 19.357; 95% CI, 1.022-366.589) were related to pars tensa cholesteatoma.

CONCLUSION

Children with adhesive otitis media should be carefully followed up in the outpatient setting. Ears with poor mastoid development may develop pars tensa cholesteatoma. Additionally, ears with middle ear effusion, total adhesion, and the presence of otorrhea tend to be at risk of pars tensa cholesteatoma. Tympanoplasty or tympanostomy tube insertion should be considered for children with adhesive otitis media who have these risk factors to prevent progression to pars tensa cholesteatoma.

Superior Semicircular Canal Dehiscence : Covering Defects in Understanding from Clinical to Radiologic Evaluation

Superior semicircular canal dehiscence alters the normal fluid mechanics of the vestibulocochlear system and can be a debilitating condition. This article reviews the current understanding of the bony labyrinthine defect, including symptoms, etiology, surgical approach, as well as preoperative and postoperative imaging pearls.

Incidental mastoid opacification in children on MRI

BACKGROUND

The opacification the mastoid cavity is frequently reported by radiologists on cross-sectional imaging done for non-otological indications. It is well known that presence of fluid the mastoid does not amount to mastoiditis. This study seeks to provide an evidence-based confirmation of this known finding.

OBJECTIVE

The purpose of our study was to determine the prevalence of mastoid opacification in children undergoing outpatient brain MRI examination.

MATERIALS AND METHODS

Our study included 515 outpatient children who had brain MRI for indications other than mastoiditis or otitis media from January 2014 to March 2014. Children with history of skull base trauma or radiation were excluded. The age range was 15 days to 18 years. The overall prevalence of mastoid opacification was determined using one sample proportion and exact 95% Clopper-Pearson confidence intervals. The prevalence of mastoid opacification was analyzed based on gender, age and presenting symptoms using chi-square test of association.

RESULTS

One hundred ten children (21.4%) had mastoid opacification. Younger patients tended to have higher opacification rates with the prevalence in children younger than 1 year of age and between 1 and 2 years of age as high as 41.7% (20/48) and 47.5% (38/80), respectively.

CONCLUSION

The diagnosis of mastoiditis in children should not be based upon a radiologist's report of finding fluid or mucosal thickening in the mastoid air cells as incidental opacification the mastoid is seen frequently.