Demonstrating Petrous Dural Incision Technique for Vascular Releasing and Transposition of Dura-Embedded Subarcuate Loop of Anterior Inferior Cerebellar Artery During Retrosigmoid Approach

BACKGROUND AND IMPORTANCE: In practice, the retrosigmoid approach is one of the most preferred approaches for cerebellopontine tumors, vascular compression syndromes, brainstem lesions, and many other pathologies. The anatomy of this region can vary, and the anterior inferior cerebellar artery is rarely involved. A dura-embedded subarcuate loop is one of these; it needs to be released and transposed to expand the surgical corridor. We present this report on expanding surgical exposure during the retrosigmoid approach in a case involving a dura-embedded subarcuate loop. CLINICAL PRESENTATION: A 44-year-old man underwent microvascular decompression by the retrosigmoid approach because of trigeminal neuralgia. During surgery, a dura-embedded subarcuate loop of the anterior inferior cerebellar artery was encountered. The subarcuate loop was hanging from the petrous bone spur. We safely released the subarcuate loop from the petrous bone spur by the dural incision technique, and further deep dissection and microvascular decompression were performed. The critical steps of the surgery were reviewed in a surgical video. CONCLUSION: These types of vascular variations can be encountered in any surgery using the retrosigmoid approach, and if the vessel is not released, it may be required to work through a narrow surgical corridor in prolonged surgeries. With this petrous dural incision technique, the vessel can be safely dissected from the bone, and the surgical corridor can be widened.