The Management of Petrous Apex Cholesteatomas in the Era of Diffusion-Weighted MRI Imaging: Scanning Frequency, Growth Rates, and the Timing of Intervention

Objective: To review the outcomes of patients with petrous apex cholesteatoma treated during the past decade; to analyze rates of recurrent cholesteatoma, including the growth rate where, appropriate; and to discuss issues related to the timing of postoperative follow-up scans and surgical intervention.

Design: Retrospective review of case notes.

Patients: Nine patients with an average age of 39 years (range, 18–68 years) were identified. All patients underwent petrosectomy; one of them was combined with a middle fossa approach. All patients were followed with diffusion-weighted magnetic resonance imaging (dMRI).

Methods: Review of sequential dMRI images; review of medical records.

Results: Five patients required further surgery due to growth of cholesteatoma. In one case, probable cholesteatoma is believed to be stable. In four cases, a growth rate (mean, 5.5 mm annually; range, 2–10 mm annually) could be calculated. In cases where surgical intervention took place, this was greater than 4 years following original surgery.

Conclusions: Petrous bone cholesteatomas are rare lesions requiring extensive surgical resection, with total removal of the lesion extremely challenging due to the proximity of important neural and vascular structures. In many cases, a less-than-total resection is achieved, either by design or inadvertently. In this series, we have demonstrated a relatively high recurrence rate, but illustrate the value of postoperative dMRI scanning. We propose a protocol to govern the frequency of surveillance scans: first scan at 6/12 months postoperatively, second scan at 2 years postoperatively, with subsequent scans at 2-year intervals if residual or recurrent disease is seen. Scans can be performed every 5 years if stable.