The retrosigmoid keyhole approach to the cerebellopontine angle: a modified surgical technique and the evaluation of cerebrospinal fluid fistulas

Abstract: Cerebrospinal fluid (CSF) leakage is a common postoperative complication after suboccipital craniotomies and can develop into a potentially life-threatening situation. Advances in dural replacement materials have revolutionized the treatment of CSF leaks and provide innovative alternatives to traditional repair methods. Synthetic and biological dural replacement materials, as well as fibrin sealants and tissue engineering approaches, offer improved durabilit, biocompatibility, and regenerative properties. However, to avoid complications associated with biomaterials and to minimize the use of dural substitutes whenever possible, careful surgical technique is essential for dural closure. Therefore, the aim of this study was to analyze the utility of a modified surgical technique for the retrosigmoid keyhole approach in reducing postoperative CSF leaks. A total of 168 consecutive patients were included in this retrospective study. All of them underwent surgery between 2015 and 2024 at our clinic for lesions in the cerebellopontine angle. A retrosigmoid keyhole approach was used in all cases. Two patients (1.2%) of the 168 developed a postoperative CSF leak: 1 (0.6%) incisional and 1 (0.6%) non-incisional. None of them developed CSF leak-related meningitis. The small retrosigmoid approach combined with the sandwich dural closure technique proved effective in reducing postoperative CSF leakage. While biomaterials contribute to improved dural sealing, careful surgical handling of posterior fossa structures remains essential for optimal outcomes.