Mastoid Portion Of Facial Nerve Research Articles

On the radiologic anatomy of pediatric sinus tympani: HRCT study

ObjectiveSinus tympani (ST) is considered the most constant among retrotympanic recesses but it is of great anatomical variability in shape and relation to mastoid portion of facial nerve. ST is difficult to access when clearing the cholesteatoma or serving as a window for cochlear implantation. The objective was to describe morphology of ST and assess feasibility of retrofacial approach in children under 5 years old. MethodsHRCT images of 150 children were reviewed. The type of sinus tympani was assessed according to Marchioni's classification. Width of entrance to sinus tympani (STW), depth of ST (STD), distance between the posterior semicircular canal and facial nerve (F-PSC), distance between the latter plane to the floor of ST at the right angle (P-ST) were measured. Width (HS-SS) and length (ML) of mastoid process were also measured. ResultsFrom 300 temporal bones analyzed, the most common type of ST was type B (59.3%), followed by type C (34.3%) and type A (6.3%). The average depth of ST was 3.38±1.04 mm (1.32-8.24 mm) and mean value of F-PSC (width of retrofacial approach) was 4.91±0.75. The depth of ST (STD) presented significant deviations (ANOVA, p<0.05) among all three types. The value of ML increased with age (very high correlation). ConclusionDeep tympanic sinus (type C) is more frequent in children than in adult populations and it may suggest that pneumatization may affect the development of tympanic sinus final shape. Retrofacial approach can be used in selected pediatric patients after HRCT analysis.

Location of the stapedius muscle with reference to the facial nerve in patients with unilateral congenital aural atresia: implication for active middle ear implants surgery

Background: Detailed investigations of the stapedial muscle (SM) in congenital aural atresia (CAA) patients have yet to be adequately conducted.Objectives: To assess image variations in the mastoid segment of the facial nerve (FN) and SM in CAA.Materials and methods: A total of nine patients comprising of 9 ears with unilateral CAA were studied. The courses of the FN and SM were evaluated from the basic point to 1 mm intervals between the mastoid portion of FN, and measured from the mean X and Y values in each group.Results: The atresia side of FN among the Y values showed significant differences compared to the contralateral side. In terms of the SM, there were no significant differences in both the X and Y values. The stapedial muscle of the CAA patients was located medially to the FN. Conversely, the distance from the PSC to the FN revealed no significant differences with regard to the X and Y values for each group.Conclusion: The current observations revealed that the SM is located more posterior to the FN in CAA patients, and this is mainly attributed to the laterally and anteriorly displaced FN.

Diagnosis of the pathological exposure of the mastoid portion of the facial nerve by CT scanning

Conclusions. High resolution CT imaging can provide useful information about the pathological exposure of the mastoid portion of the facial nerve before mastoid surgery and can assess the injury site of the facial nerve after operation. Objectives. To evaluate the diagnostic value of high resolution CT scanning of pathological exposure of the mastoid portion of facial nerve and provide valuable information for otologic surgery, and to analyse the cause of facial nerve paralysis after operation. Materials and methods. Routine CT scanning was used to examine patients with chronic suppurative otitis media and external auditory canal cholesteatoma preoperatively by axial-transverse and coronal views. If there was any pathological exposure of the mastoid portion of the facial nerve on CT imaging, then this was compared with intraoperative findings. In addition, one patient who had suffered postoperative facial nerve paralysis was also examined by CT scanning to determine whether any pre-existing pathological exposure of facial nerve could be found. Results. Through routine CT scanning six patients with chronic suppurative otitis media and three patients with external auditory canal cholesteatoma were found to have pathological exposure of the mastoid portion of the facial nerve. Coronal views could more clearly show the size and the position of the exposure; the corresponding surgical findings (pathological exposure) for the facial nerve could be confirmed in all nine patients. CT imaging could also show that the patient who had suffered postoperative facial nerve paralysis did indeed have pre-existing pathological exposure of the mastoid portion of the facial nerve.