Most common site of perilymph fistula ?
Ans. is 'b' i.e., Oval window Perilymph fistula In this condition, perilymph leaks into the middle ear through the oval or round window. Perilymphatic fistula (so positive fistula test) may occur due to a defect in one of three locations : 1. Oval - window (most common site) Stapedectomy surgery (for otosclerosis) Head trauma or Barotrauma (Pressure injury) Acoustic trauma 2. Round window (rupture of round window membrane) Barotrauma :- SCUBA diving, airplane pressurization Congenital malformations (mondini dysplasia) 3. Otic capsule Another possible location for a fistula is in the bone of the ear (the otic capsule). This is a rare condition where the bone between the ear and brain area is missing or thin, causing symptoms very similar to that of round or oval window fistula. Causes are :- Superior canal dehiscence syndrome Cholesteotoma Fenestration surgery (surgically created window in horizontal SCC) Erosion of Horizontal (lateral) SCC due to any cause Temporal bone fracture Micro fissure
Round window
Oval window
Otic capsule
Attic