Background <p>Chronic suppurative otitis media (CSOM) involves persistent middle ear inflammation, often leading to tympanic membrane perforation and hearing loss. Tympanic isthmus patency is key to middle ear ventilation, influencing tympanoplasty outcomes.</p> Aim <p>The objective of this study is to evaluate the patency of the tympanic isthmus and assess its impact on the success rate of myringoplasty in patients with the tubotympanic type of CSOM.</p> Patients and methods <p>A prospective clinical study was conducted on 38 patients diagnosed with tubotympanic CSOM, with either unilateral or bilateral presentation. All patients underwent transcanal myringoplasty, and endoscopic evaluation of the tympanic isthmus was performed intraoperatively to assess patency. Patency restoration was performed in cases of obstruction. Patients were followed up for three months postoperatively, with assessment of tympanic membrane closure and audiometric outcomes.</p> Results <p>The study included 38 patients (63.2% female, mean age 26.2 ± 14.5&#xa0;years). Tympanic isthmus obstruction was identified in 71.1% of cases. Myringoplasty success, defined as complete tympanic membrane closure, was achieved in 65.8% of patients. A significant reduction in the mean air–bone gap was observed, from 19.2 ± 7.9&#xa0;dB preoperatively to 12.8 ± 7.5&#xa0;dB postoperatively (<i>P</i> = 0.02). While tympanic isthmus patency showed no significant correlation with tympanic membrane closure rates (<i>P</i> = 0.13), patency restoration improved overall middle ear ventilation and hearing outcomes.</p> Conclusions <p>Endoscopic evaluation of the tympanic isthmus and restoration of its patency during myringoplasty can enhance middle ear ventilation and improve audiometric outcomes in patients with tubotympanic CSOM.</p>