Sanna Classification and Prognosis of Cholesteatoma of the Petrous Part of the Temporal Bone: A Retrospective Series of 81 Patients.

OBJECTIVE

To determine how classification of petrous bone cholesteatomas (PBCs) using the 5-point Sanna classification can predict major structural involvement, facial nerve outcomes, hearing outcomes, postoperative complications, and disease recurrence.

STUDY

DESIGN

Retrospective case series.

SETTING

Tertiary referral center in Bergamo, Italy.

PATIENTS: Eighty-one sequential patients with radiologic and surgically confirmed diagnoses of PBC treated at a single tertiary referral center during a 20-year period.

MAIN OUTCOME MEASURES: Major structural involvement, facial nerve outcomes, hearing outcomes, postoperative cerebrospinal fluid leak, and disease recurrence were evaluated on the basis of Sanna classification.

RESULTS

Using the Sanna classification, 70% (57) were supralabyrinthine, 12% (10) infralabyrinthine, 7% (6) infralabyrinthine-apical, 5% (4) apical, and 5% (4) massive. Massive classification was statistically significantly associated with cochlear involvement (p = 0.009) and internal auditory canal involvement (p = 0.02). The infralabyrinthine-apical class was associated with carotid canal involvement (p = 0.03). Facial nerve interruption was observed in 35% of patients and most frequently in the apical group (75%). Neither hearing nor facial nerve outcomes were associated with Sanna classification. House-Brackmann score improved or was maintained postoperatively in 89% of patients.

CONCLUSION

The Sanna classification provides anatomic detail on location of PBCs and is predictive of IAC, cochlear, and carotid artery involvement. However, classification systems for this rare condition continue to pose a challenge in being able to accurately predict facial nerve and hearing outcomes in surgical obliteration of PBC.