Cochlear-facial dehiscence - the most common cause of facial nerve stimulation from a cochlear implant? A case-control study.

OBJECTIVES: To investigate the prevalence of cochlear-facial dehiscence (CFD) and other radiographical pathologies in ears with facial nerve stimulation (FNS) from a cochlear implant (CI). METHODS: Retrospective case-control study of 27 patients with CI and FNS on either ear (study group) and 27 patients without FNS, matched for age, sex and type of electrode array (control group). Preoperative CT scans of all 108 ears were re-evaluated. Subanalyses included comparisons between the study and control groups and associations between FNS and radiographic pathologies. RESULTS: CFDs were detected in 20 of 54 ears (37%) in the study group and in 3 of 54 ears (6%) in the control group (P < 0.001). The corresponding numbers of otosclerosis were 10 (18%) and 0 (P = 0.011) and of developmental anomalies 16 (30%) and 8 (15%) (not significant). FNS was present in 33 ears in the study group, of which 14 (42%) had a CFD. FNS was absent in six ears with CFD and CI, four of which contralateral to an ear with FNS. Eight of 14 ears with FNS and CFD had a lateral electrode array and six had a perimodiolar electrode array. We found no association between the presence of CFD and stimulation thresholds for FNS. The adjusted odds ratio for developing FNS in the presence of a CFD was 9.9 (95% CI 2.7-36.0). CONCLUSIONS: CFD was the most common radiographic pathology in ears with FNS, with a 10-fold increased risk of FNS. To avoid CI-related FNS, preoperative CT scan and awareness of typical dehiscence symptoms are strongly recommended.

Calcific tendinitis of the longus colli muscle. / Kalsifiserende tendinitt i m. longus colli.

BACKGROUND: Calcific tendinitis of the longus colli muscle is an aseptic inflammatory reaction to calcium hydroxyapatite crystal deposition in the cervical prevertebral space. CASE PRESENTATION: A 40-year-old woman presented with neck pain and odonyphagia. She had reduced mobility in her neck, tenderness to palpation and elevated CRP with normal leukocyte count and sedimentation rate. CT revealed a fluid collection in the retropharyngeal space and a calcific deposition in the longus colli muscle consistent with calcific tendinitis. She improved with NSAID therapy. Blood cultures taken on arrival showed no growth. INTERPRETATION: Acute calcific tendinitis of the longus colli muscle is an aseptic inflammatory process in the cervical prevertebral space and an important mimicker of retropharyngeal abscess and spondylodiscitis.

Fusion of Technology in Cochlear Implantation Surgery: Investigation of Fluoroscopically Assisted Robotic Electrode Insertion.

The HEARO cochlear implantation surgery aims to replace the conventional wide mastoidectomy approach with a minimally invasive direct cochlear access. The main advantage of the HEARO access would be that the trajectory accommodates the optimal and individualized insertion parameters such as type of cochlear access and trajectory angles into the cochlea. To investigate the quality of electrode insertion with the HEARO procedure, the insertion process was inspected under fluoroscopy in 16 human cadaver temporal bones. Prior to the insertion, the robotic middle and inner ear access were performed through the HEARO procedures. The status of the insertion was analyzed on the post-operative image with Siemens Artis Pheno (Siemens AG, Munich, Germany). The completion of the full HEARO procedure, including the robotic inner ear access and fluoroscopy electrode insertion, was possible in all 16 cases. It was possible to insert the electrode in all 16 cases through the drilled tunnel. However, one case in which the full cochlea was not visible on the post-operative image for analysis was excluded. The post-operative analysis of the electrode insertion showed an average insertion angle of 507°, which is equivalent to 1.4 turns of the cochlea, and minimal and maximal insertion angles were recorded as 373° (1 cochlear turn) and 645° (1.8 cochlear turn), respectively. The fluoroscopy inspection indicated no sign of complications during the insertion.

CT imaging of the Eustachian tube using focal contrast medium administration: a feasibility study in humans.

Several methods of imaging the Eustachian tube have been tested in the last century, although neither has led to an established method. The introduction of balloon Eustachian tuboplasty (BET) has revived the request for Eustachian tube (ET) visualization in patients with chronic Eustachian tube dysfunction. Many institutions perform preoperative computed tomography (CT) scans of the temporal bone and epipharynx before BET. Purpose We hypothesize that the injection of a contrast medium into the tympanic cavity is safe and feasible and can evolve the CT scan by visualizing the ET lumen and, potentially, the level of obstruction. This study is the initial feasibility study for such a human application. Material and Methods Ten minutes before a CT scan, diluted iodixanol was injected into the middle ear in 18 patients planned for BET due to otitis media with effusion. Five patients with Meniere's disease were controls. Any immediate or delayed adverse events were recorded. Masking of adjacent bony structures in the middle ear on the CT images was evaluated and the most caudally visible contrast medium between the middle ear and epipharynx recorded. Results There were no serious adverse events. One patient reported transitory vertigo. The contrast medium did not mask middle ear structures, apart from the tympanic membrane. The level of contrast medium passage could be assessed. Conclusion Visualizing the ET lumen in humans using intratympanic contrast medium is feasible and safe and does not obscure other valuable image information in a preoperative CT scan.

Abnormally wide eustachian tubes involving the sphenoid bone: A collection.

OBJECTIVES: To present nine patients with an abnormal widened bony Eustachian tube running anteriorly in the skull base through the sphenoid bone. METHODS: Patients with a particular anomaly in the bony Eustachian tube incidentally found on CT examinations were registered consecutively over a period of four years. RESULTS: Nine patients had the anomaly, eight unilaterally and one bilaterally. All our patients had additional anomalies involving the outer, middle, and/or inner ear. CONCLUSION: The consequences of this anomaly remain unknown, but the presence of the widened, bony ET should increase the awareness for complex temporal bone deformities and vice versa. LEVEL OF EVIDENCE: 4.

The cartilaginous Eustachian tube: Reliable CT measurement and impact of the length.

PURPOSE: Balloon dilation of the Eustachian tube is a treatment option for obstructive Eustachian tube dysfunction. The desired balloon position is in the cartilaginous portion. However, the balloon catheter may slide into the bony portion without the surgeon's knowledge. Knowing the length of the cartilaginous portion may improve catheter positioning, but there is no published research on measuring this portion selectively or on whether the length has an impact on development of disease or treatment outcome. To evaluate whether a measurement obtained from CT images is valuable and accurate, to standardize the manner of which the length is measured, and to compare our radiologic measurements to procedural findings, we designed a combined study. Further, we tested the length's influence on development of disease and treatment outcome. METHODS: Anatomical end points of the cartilaginous part of the Eustachian tube were unambiguously defined. The length was retrospectively measured bilaterally in 29 CT examinations by two radiologists, and repeated by one after two weeks. New reformats and measurements were made after 18 months for 10 of the patients. Prospectively 10 patients were included in a study where the length measured on CT was compared to per-procedural measurements based on catheter insertion depth to isthmus. Various parameters including length and treatment outcome were measured in 69 patients and 34 controls. RESULTS: Correlation was adequate to excellent in all comparisons. The length of the cartilaginous Eustachian tube did not predict treatment outcome or disease development. The lengths were significantly shorter in females. CONCLUSION: Measuring the cartilaginous portion of the Eustachian tube on CT images is precise and reproducible, and reflects the length measured intraoperatively. However, it does not seem have a prognostic value.

CT imaging of the eustachian tube using focal contrast medium administration: a feasibility study.

OBJECTIVES: We aim to develop an imaging technique for visualization of the Eustachian tube (ET) lumen. STUDY DESIGN: A prospective, experimental study in an animal model and in human cadaver specimens. METHODS: Applying iodixanol to the middle ear in two human temporal bone specimens, followed by computed tomography (CT) examinations, we optimized contrast dilution, CT algorithm, and head positioning for visualization of contrast passage through the ET. Myringotomy was performed on eight rabbits. Based on the cadaver study, a 20% iodixanol solution was applied to the middle ear, and subsequent CT scans were performed to observe iodixanol in the epipharynx. For some animals, the procedure was repeated on the contralateral ear. We performed the procedure twice on four subjects. Twenty examinations were included. Iodixanol appearance in the ET and the epipharyngeal orifice was assessed qualitatively on CT scans. The tympanic membrane was inspected after 1 or 2 weeks, and histopathological examination of six contrast-exposed temporal bones was performed. RESULTS: The cadaver study provided information on imaging technique and contrast dosage. In rabbits, iodixanol passed through the ET in 19 of the 20 ears. Qualitatively, optimal visualization was seen after 9 to 12 minutes. Clinical inspection after 1 or 2 weeks revealed normal middle ear status. Histopathological samples showed no sign of inflammatory reaction in the tympanic membrane, middle ear, or ET. CONCLUSION: Iodixanol application to the middle ear is feasible, safe, and demonstrates patency of the ET. LEVEL OF EVIDENCE: N/A.