Objective To investigate the incidence of facial nerve dehiscence in patients undergoing modified radical mastoidectomy for middle ear cholesteatoma and to delineate the associated risk factors,thereby furnishing surgical guidelines for clinical practice.Methods A retrospective analysis was conducted on the clinical data of 296 patients (301 ears) who underwent modified radical mastoidectomy for middle ear cholesteatoma in Meizhou People's Hospital between January 2016 and September 2023.Univariate and multivariate logistic regression analyses were employed to assess the relationship between facial nerve dehiscence and variables such as sex,age,disease duration,surgical ear,lateral semicircular canal fistula,dural exposure,sigmoid sinus exposure,external auditory canal posterior wall destruction,mastoid gasification type,stapes destruction,scutum destruction.Results Facial nerve dehiscence was observed in 118 ears (39.2%) of the 301 ears post-modified radical mastoidectomy for middle ear cholesteatoma.The tympanic segment was the most common site of dehiscence (83.1%) (98/118).Univariate analysis identified that there were significant differences in external semicircular canal fistula,dural exposure,stapes destruction,sigmoid sinus exposure,posterior wall destruction of external auditory canal and scutum destruction between facial nerve dehiscence(+)and exposed facial nerve dehiscence(-)(P＜0.05).Multivariate logistic regression analysis revealed that lateral semicircular canal fistula (β=0.993, OR=2.700,95%CI=1.380-5.279),stapes destruction (β=1.794, OR=6.014,95%CI=3.453-10.477),and posterior wall destruction of the external auditory canal (β=1.124,OR=3.078,95%CI=1.587-5.971)were significant risk factors for facial nerve dehiscence.The risk escalated with an accumulation of these risk factors,notably,when lateral semicircular canal fistula,stapes destruction,and posterior wall destruction of the external auditory canal co-occurred,the risk of facial nerve dehiscence amplified by 16.3 times (β=2.791, OR=16.290,95%CI=3.704-71.643).Conclusion The incidence of facial nerve dehiscence in middle ear cholesteatoma was 39.2%,predominantly located in the tympanic segment.Lateral semicircular canal fistula,stapes destruction,and posterior wall destruction of the external auditory canal were discerned as risk factors,with their accumulation markedly escalating the risk of facial nerve dehiscence.