Petrosquamosal sinus: Clinical characteristics based on radiologic and operative findings

OBJECTIVE: Petrosquamosal sinus (PSS) is an embryonic emissary vein of the temporal bone connecting the intracranial and extracranial venous networks, which is present in some variants of venous cerebral drainage. The aim of the present study was to analyze 20 cases of PSS and to present its clinical characteristics and implications. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURE: By reviewing retrospective medical records and TBCT findings, a total of 20 PSS cases were found. Based on the shapes of PSS demonstrated on TBCT, PSS was classified into tortuous and straight types. The course and thickness of PSS were also investigated. The average thicknesses of PSS between tortuous and straight types were compared. RESULTS: The mean age of the patients was 54.1 ± 16.2 years. The study group consisted of 7 male (35.0%) and 13 female (65.0%) patients. Eleven cases were found on the right side and 8 cases on the left side. The mean diameter of the bony canal that PSS courses on TBCT was 2.57 ± 0.88 mm. Its maximal and minimal diameters were 4.2 and 0.7 mm. The average diameter of tortuous type PSSs (3.04 ± 0.75 mm) was significantly larger compared with that of straight-type PSSs (2.09 ± 0.76 mm) (p < 0.05). CONCLUSION: Preoperative identification of PSS using TBCT may be important for safe mastoid surgery. The presence of PSS should be identified with thorough examination of radiographic findings before mastoid surgery.