The purpose of this study was to develop methods for quantitative analysis of Eustachian tube (ET) function to supplement video endoscopy and to apply the knowledge gained to the creation of new surgical procedures to treat refractory dilatory or patulous dysfunction of the ET. Prospective studies were performed on adult normal subjects and patients with otitis media with effusion (OME) or patulous ETs in tertiary medical centers and on human cadaver heads. Timing and metric parameters were measured from the endoscopic videos. Analyses of endoscopy with simultaneous sonotubometry were conducted in normal subjects. Patients with refractory OME underwent laser Eustachian tuboplasty (LETP) procedures to vaporize mucosa, submucosa, and cartilage, thinning the postero-medial wall of the ET. The feasibility and safety of an alternative procedure, balloon dilation of the ET was investigated in cadavers and then performed on patients with refractory OME. Patients with patulous ETs underwent surgical augmentation of the concave defect found in the antero-lateral wall. Diagnostic analyses were done on 27 normal, 13 OME and 15 patulous subjects.
Mean values for normals: angle of torus tubarius rotation 34.2° (SD 14.3) and excursion of the antero-lateral wall 35.5 % of torus tubarius height (SD 16.3). Lateral excursion wall was significantly less in patulous ET (18.7%, SD 15.1, p=0.001) and in OME (23.9%, SD 21.7, p=0.048). During sonotubometery, all showed normal endoscopy and appeared to open, but only 11/17 opened by objective criteria of 5 dB increase in signal with swallows (ave. duration 0.43 s) and 13/17 with yawns (ave.2.03s). LETP in conjunction with tympanostomy tube was performed in 13 patients and eliminated OME in 4/11 at 6 months, 3/10 at 1 year, and 3/8 at 2 years. Balloon dilation catheters successfully dilated all cadaver ETs without significant adverse effects and average tubal volume increased from 0.16 to 0.49 cm3 (SD 0.12). In 11 patients undergoing balloon dilation, all cases successfully dilated. 11/11 could autoinsufflate by Valsalva (p<0.001); tympanograms were A: 4/11, C: 1/11, or open (perforation or tube): 6/11. All atelectases resolved. There were no complications related to the dilation. 14 patients underwent patulous ET reconstruction; 1 had complete relief, 5 had significant improvement and were satisfied, 7 improved but were dissatisfied, and 1 was unchanged. There were no complications.
The ET contains a functional valve within the cartilaginous segment and its failure may leads to middle ear disorders. On video endoscopy, lateral excursion of the antero-lateral wall was reduced in OME and patulous ETs. This parameter can now be further studied in the search for pathophysiology of tubal dysfunction. Sonotubometry failed to record tubal opening in all subjects, but when it occurred it was more accurately determined than by endoscopy. The combined technology provides complimentary information and is promising for future use. LETP was safe, without significant complications, and could improve severely refractory OME. It is promising for expanded indications in ET surgery.
Alternatively, balloon dilation was shown to be safe, technically feasible and with some reasonable possibility for clinical efficacy. Randomized clinical trials of the procedure are indicated. Patulous ET reconstruction was successful in relieving symptoms and future work is needed to improve the instrumentation and graft materials.
