关键词: 上半规管裂综合征, 乳突, 眩晕, 血管性耳鸣, 前庭诱发肌源性电位

Abstract: Objective To investigate clinical characteristics of patients with superior semicircular canal dehiscence syndrome (SSCDS), and to analyze the surgical outcome of the transmastoid approach. Methods From May 2015 to September 2021, the clinical data of SSCDS patients who underwent surgical treatments in Department of Otolaryngology-Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University were retrospectively analyzed, and postoperative follow-ups were conducted. Surgical methods included the repair of the superior semicircular canal dehiscence and the occlusion of superior semicircular canal via transmastoid approach. According to the improvement of patients' symptoms after operation, the postoperative effect was divided into three types (cured, improved and invalid). Results There were 10 patients in the study, including 5 males and 5 females. Nine cases had unilateral SSCDS, and the remaining one had bilateral SSCDS. Common symptoms were bone-conduction hyperacusis, vascular pulsatile tinnitus, vertigo induced by loud sounds, and vertigo caused by pressure changes in middle ear or intracranial cavity. All were unilateral operations. Four patients underwent the repair of the superior semicircular canal dehiscence via transmastoid approach, and the remaining six patients underwent the occlusion of superior semicircular canal via transmastoid approach. One patient was lost to follow-up after surgery. Among nine patients who were followed up for 4-73 months, five patients recovered, three patients got improved, and one patient was invalid. The potential reason for the failure of the operation was that the patient's middle cranial fossa was low, and it was difficult to expose the gap between the dura and the arcuate eminence during the surgery of repair of the superior semicircular canal dehiscence, which resulted in inadequate repair. All patients had no serious postoperative complications such as cerebrospinal fluid leakage or intracranial infection. Conclusion Transmastoid approach for repair of the superior semicircular canal dehiscence and transmastoid approach for the occlusion of superior semicircular canal are both safe and effective for SSCDS. The surgery of the occlusion of superior semicircular canal is more accessible, especially for patients with low middle cranial fossa.

Key words: superior semicircular canal dehiscence syndrome, mastoid, vertigo, vascular pulsatile tinnitus, vestibular evoked myogenic potential