Distance from the Labyrinthine Portion of the Facial Nerve to the Basal Turn of the Cochlea Temporal Bone Histopathologic Study

Redleaf, Miriam; Blough, Richard R.

doi:10.1177/000348949610500416

Cited by 17 publications

(15 citation statements)

References 7 publications

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“…19 Other studies also demonstrate similar findings in cadaveric measurements. 11, 20 In the current study, radiographic measurements in the axial plane were significantly lower in the FNS cohort than the control group (0.3mm vs 0.6mm). We also found our FNS cohort had a significantly smaller distance between the cochlea and FN than the control group (0.4mm vs. 0.6mm) in the coronal plane.…”

Section: Discussioncontrasting

confidence: 40%

Can Preoperative CT Scans Be Used to Predict Facial Nerve Stimulation Following CI?

Hatch

Rizk²,

Moore³

et al. 2017

Otology &Amp; Neurotology

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Objectives 1) Determine the ability of pre-operative CT to predict facial nerve stimulation (FNS) after cochlear implantation (CI). 2) Recognize the limitations of CT in predicting FNS. Study Design Case control study Setting Tertiary care academic medical center. Subjects Adult patients with CI from 2003–2015 Methods Patients with severe FNS (n=4) were compared with randomly selected CI patients (n=28). Three blinded reviewers evaluated preoperative temporal bone CT scans to measure the distance from the labyrinthine segment of the facial nerve (LSOFN) to the basal turn of the cochlea (BTOC) and attempted to predict whether or not the subject had FNS after CI. Results In total 32 CT scans were evaluated representing 49 ears that underwent cochlear implantation. The distance (mm) measured from the LSOFN to the BTOC in both the axial (0.3 ± 0.3 vs. 0.6 ± 0.3) and coronal (0.4 ± 0.2 vs. 0.6 ± 0.2) orientation were significantly different between the two groups (p=0.0001 and p=0.0034) respectively. The intra-class correlation coefficient demonstrated good (K > 0.7) reviewer correlation in both the reviewers’ measurements and predictions. The sensitivity, specificity, positive predictive value, and negative predictive value for pre-operative CT scans to predict FNS were 38.5%, 85.1%, 19.2%, and 93.8% respectively. The reviewers were 23% accurate in predicting FNS. Conclusion Based on a blinded retrospective case-control study, CT scan measurements show a significantly reduced distance between the labyrinthine facial nerve and the basal turn of the cochlea in patients with FNS. However, it is difficult to predict who will have FNS based on these measurements.

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Section: Discussioncontrasting

confidence: 40%

Can Preoperative CT Scans Be Used to Predict Facial Nerve Stimulation Following CI?

Hatch

Rizk²,

Moore³

et al. 2017

Otology &Amp; Neurotology

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show abstract

“…The average measurement of the single-celled anterior epitympanic recess was 3.3 mm (range, 1.0-5.5) in the anteroposterior dimension and 3.4 mm (range, 1.0-7.0) in the transverse dimension [4] . The distance from the ampullated end of the superior semicircular canal to the geniculate ganglion or geniculate ganglion fossa ranged from 2.06 to 4.88 mm in a temporal bone histopathologic study [5] , and the results appear to be consistent with our results obtained from the CT images of 67 patients for whom we had performed tympanoplasty. In such a narrow space, close attention should always be paid to the anatomy of the facial nerve from the labyrinthine segment to the geniculate ganglion when a surgical treatment such as decompression of the facial nerve or tympanoplasty is performed.…”

Section: Discussionsupporting

confidence: 87%

Anterior Displacement of the Geniculate Ganglion

Tachibana

Orita²,

Nishizaki³

2016

Int Adv Otol

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We present the case of a 34-year-old Japanese woman with cholesteatoma of the middle ear. During the operation, this patient showed an unusual position of the geniculate ganglion. We reviewed the computed tomography (CT) images targeting the ear of the present case after the operation. We found that the shortest ranges from the ampullated end of the superior semicircular canal to the geniculate ganglion fossa were 5.1 mm on both sides. We did not find any cases with obvious dislocation of the geniculate ganglion among the 67 cases for which we had performed tympanoplasty. Displacement of the geniculate ganglion is either extremely rare or typically unnoticed because this abnormality is asymptomatic. We speculated that the unusual position of the geniculate ganglion was due to an incomplete development of the tympanic tegmen. When surgical treatment such as decompression of the facial nerve or tympanoplasty is performed, close attention should always be paid to the anatomy of the facial nerve from the labyrinthine segment to the geniculate ganglion. In the present case, although connective tissues existed around the anterior epitympanic recess, we left this lesion to avoid iatrogenic facial palsy.

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“…For instance, the average distance between the labyrinthine portion of the facial nerve and cochlea has been reported to be 0.4 mm. 10 The position of the cochlea corresponds to the area medial to the first genu of the facial canal and posterior to the groove of the GSPN, and its apex is located just underneath the proximal groove of the GSPN (Fig. 4).…”

Section: Discussionmentioning

confidence: 99%

Recovery of low-frequency sensorineural hearing loss following resection of a greater superficial petrosal nerve schwannoma

Sade

Lee²

2007

JNS

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Facial nerve schwannomas can occur anywhere from the internal auditory canal to the parotid gland. Schwannomas arising from the greater superficial petrosal nerve are exceedingly rare. The authors report the case of a 63-year-old woman who presented with a selective low-frequency hearing loss of 3 weeks' duration. Neurological examination demonstrated a House-Brackmann Grade II facial paresis and asymmetrical hearing loss on the left side. Audiometric evaluation showed a significant loss of low-frequency hearing with a speech reception threshold (SRT) of 30 dB and a speech discrimination score (SDS) of 88% on the left side. Magnetic resonance imaging revealed a 2.4-cm enhancing left middle fossa mass. Near-complete resection was performed via a left temporal craniotomy. The tumor was located in the Glasscock triangle and had invaded the petrous bone overlying the cochlea. A very small piece of the tumor over the cochlea was left in order to preserve hearing. A postoperative audiogram showed significant improvement in the patient's hearing, with an SRT of 20 dB and an SDS of 100%. The histological findings were consistent with schwannoma. The patient experienced postoperative improvement of hearing function despite cochlear involvement, which has previously been reported as an unfavorable factor for postoperative hearing outcome in facial nerve schwannomas.

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Distance from the Labyrinthine Portion of the Facial Nerve to the Basal Turn of the Cochlea Temporal Bone Histopathologic Study

Cited by 17 publications

References 7 publications

Can Preoperative CT Scans Be Used to Predict Facial Nerve Stimulation Following CI?

Can Preoperative CT Scans Be Used to Predict Facial Nerve Stimulation Following CI?

Anterior Displacement of the Geniculate Ganglion

Recovery of low-frequency sensorineural hearing loss following resection of a greater superficial petrosal nerve schwannoma

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