Clinical Features of Non-simple Lateral Semicircular Canal Fistula
XU Ting
YI Xinsheng
ZHANG Yongsheng
Abstract：Objective To report clinical features of non-simple lateral semicircular canal fistula(NSLLF)in 10 cases to improve the understanding,diagnosis and treatment of complex labyrinthine fistula.Methods Clinical data of 10 cases of non-simple lateral semicircular canal fistula treated in our hospital from March 2020 to December 2023 were retrospectively analyzed.Results All 10 patients had varying degrees of hearing loss before surgery,with mixed hearing loss being the most common,accompanied by dizziness in 4 cases.CT scan confirmed diagnosis in 9 cases.Microscopic surgeries included wall down mastoidectomy,tympanoplasty and fistula repair.During the surgery,fistula was found involving the lateral and upper semicircular canals in 2 cases,lateral and posterior semicircular canals in 3 cases,lateral,posterior and upper semicircular canals in 2 cases,posterior semicircular canal in 1 case,cochlea in 1 case,and vestibular window and lateral semicircular canal in 1 case.According to the Dornhoffer classification,all cases were classified as type III.Perforation was seen in pars tensa in 5 cases and in pars flaccida in 5 cases,respectively.Structural damage to the stapes was found in 8 cases,including missing stapes baseplate in 4 cases.Temporalis muscle and fascia were used in repair of small fistula.Temporalis muscle was used to obliterate the semicircular canal and in the"sandwich"or"four layers"fashion in repair of fistula with significant bone defect.Time to dry ear after surgery was 70.4±19.6 d.There were no significant change in bone and air conduction hearing before and after surgery,except in 2 cases with simultaneous involvement of the lateral,posterior and upper semicircular canals,where there was 10-20 dB additional bone conduction loss after surgery.experienced Postoperative dizziness was seen in 8 cases,spontaneously resolved within 1 month in most of them.Conclusion Incidence of NSLLF is low,with low rate of positive fistula test,although bony defect is relatively serious accompanied by prominent bone conduction hearing loss in patients with cochlear involvement.Preoperative CT scan often reveals the diagnosis,and the repair benefits from accurate imaging,mastery of anatomy and excellence in surgical skills.
Keywords：non simple lateral semicircular canal labyrinthine fistulaclinical featuressurgical methodtreatment effect
Publication Date：2025-07-20
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 556-560 )