Calcium Phosphate Cement Application for the Reconstruction of Mastoid Region Following Retrosigmoid Approach

The retrosigmoid approach is widely used in posterior fossa surgery and has undergone various modifications to reduce complications and improve cosmetic outcomes. One such modification involves repairing bone defects with calcium phosphate cement (CPC), which provides structural stability and favorable aesthetic results. This study aimed to evaluate the incidence of postoperative cerebrospinal fluid (CSF) leakage, wound infection, local pain, and cosmetic satisfaction in patients undergoing retrosigmoid craniotomy with CPC reconstruction of partial bone defects.

A retrospective review was conducted on 333 patients who underwent retrosigmoid craniotomy with partial bone defect reconstruction using CPC between March 2018 and June 2025. After tumor removal or decompression, the bone flap was replaced, and any residual bone defects along the craniotomy margins were repaired with CPC, which was molded to restore the skull contour. The cement was allowed to harden in situ and integrated with the surrounding bone to ensure stability. Patient records and follow-up data were analyzed for postoperative CSF leakage, wound infection, local pain, and cosmetic satisfaction.

Over a median follow-up period of 6 months (range: 3-12 mo), 2 patients (0.6%) developed postoperative CSF otorrhea, which was unrelated to the incision. No other complications, including wound infection or severe local pain, were observed. Cosmetic satisfaction was reported in 331 patients (331/333=99.4%), with only two expressing dissatisfaction.

CPC is an effective material for repairing partial bone defects in the retrosigmoid approach. Its use is associated with a low incidence of CSF leakage and high cosmetic satisfaction, without increasing the risk of wound infection or local pain.