Changes of visualised Eustachian tube lengths by age and position: Radiologic study in sitting and supine positions using cone beam and conventional CT.

OBJECTIVES: Patulous eustachian tube (ET) has been characterised by the visualisation of full-length ET on computed tomography (CT) results. We wanted to investigate the changes of visualised ET lengths by age in supine and sitting positions. DESIGN: Retrospective study. SETTING: Tertiary care academic referral centre. PARTICIPANTS: One hundred subjects who underwent cone beam CT (CBCT) in a sitting position and conventional CT in a supine position for non-otitis-related or dental complaints. MAIN OUTCOME MEASURES: Visualised ET lengths from the nasopharyngeal orifice measured by different positions and ages. RESULTS: Subjects did not show visualisation of full-length ET throughout the study. The visualised ET lengths (9.0 ± 2.5 mm) of the CBCT group were significantly larger than those (6.8 ± 2.3 mm) of the conventional CT group (P < 0.0001).Women showed longer visualised ET lengths than men in CBCT group (P < 0.001). The visualised ET lengths of the CBCT group were consistent or slightly increasing as a function of age (P = 0.06); however, the visualised ET lengths of the conventional CT group decreased as a function of age (P = 0.001). The slopes of regression lines of the two groups were significantly different. CONCLUSIONS: When in the supine position, the ET lengths gradually shortened as the subjects got older, most likely due to venous engorgement and the collapse of surrounding tissues; this finding thus suggests that CT in a supine position is an inappropriate method to diagnose patulous ET. The visualised ET lengths by CBCT in a sitting position were consistent throughout the different ages of the subjects and may be used as a diagnostic test for patulous ET.

Transnasal Placement of a Balloon-Expandable Metallic Stent: Human Cadaver Study of the Eustachian Tube.

PURPOSE: To investigate the technical feasibility of stent placement in the cartilaginous portion of the Eustachian tube (ET). MATERIALS AND METHODS: Twelve ETs of 6 cadavers were used. Two different-sized stents were placed on either the right (2.5 mm in diameter) or left (3.5 mm in diameter) side of the ET. The procedural feasibility was assessed by subtraction Eustachian tubography, computed tomography before and after the procedure, and fluoroscopic and endoscopic images. The stent location, inner luminal diameter of the stented ET, radiation dose, procedural time, and fluoroscopy time were analyzed. RESULTS: Stent placement was successful in 11 of 12 cadaveric specimens without procedure-related complications. In the 1 specimen, the balloon catheter with crimped stent was passed into the bony canal of the ET without any resistance. The distal end of the stent was located in the middle ear cavity. Stents were located within the cartilaginous portion of the ET (n = 1), the proximal tip bridging the nasopharyngeal orifice of the ET (n = 5), or the proximal end of the stent protruded from the tubal orifice (n = 5). The mean luminal diameter in the outer segment was significantly smaller than in the middle (P < .001) and inner (P < .001) segments. The mean procedure time was 128 ± 37 seconds. The mean radiation dose and fluoroscopy time of each cadaver were 3235.4 ± 864.8 cGy/cm2 and 139 ± 49 seconds, respectively. CONCLUSIONS: Stent placement of the ET under endoscopic and fluoroscopic guidance is technically feasible in a human cadaver model.

Sirolimus-eluting cobalt-chrome alloy stent suppresses stent-induced tissue hyperplasia in a porcine Eustachian tube model.

Various preclinical studies with developed Eustachian tube (ET) stents are in progress but have not yet been clinically applied. ET stent is limited by stent-induced tissue hyperplasia in preclinical studies. The effectiveness of sirolimus-eluting cobalt-chrome alloy stent (SES) in suppressing stent-induced tissue hyperplasia after stent placement in the porcine ET model was investigated. Six pigs were divided into two groups (i.e., the control and the SES groups) with three pigs for each group. The control group received an uncoated cobalt-chrome alloy stent (n = 6), and the SES group received a sirolimus-eluting cobalt-chrome alloy stent (n = 6). All groups were sacrificed 4 weeks after stent placement. Stent placement was successful in all ETs without procedure-related complications. None of the stents was able to keep its round shape as original, and mucus accumulation was observed inside and around the stent in both groups. On histologic analysis, the tissue hyperplasia area and the thickness of submucosal fibrosis were significantly lower in the SES group than in the control group. SES seems to be effective in suppressing stent-induced tissue hyperplasia in porcine ET. However, further investigation was required to verify the optimal stent materials and antiproliferative drugs.