====== Subpial Dissection ====== ===== 🔍 Definition ===== **Subpial dissection** is a [[microsurgical technique]] in which the surgeon operates beneath the pia mater, maintaining it as a protective membrane between the surgical field and the underlying brain cortex. This approach allows lesion removal or exposure of deep structures while minimizing cortical injury and preserving vascular integrity. ===== ⚙️ Surgical Technique ===== * Identify the **pial surface** under high magnification. * Incise the **pia mater sharply** using a microknife or fine bipolar forceps. * Continue dissection **beneath the pia**, using gentle suction and blunt dissection tools. * The pia is kept **intact over the brain parenchyma**, and the dissection proceeds **between the pia and the lesion or arachnoid**. * Achieve meticulous **hemostasis** using bipolar coagulation at the pial edge, avoiding direct cortical coagulation. ===== 🧭 Indications and Applications ===== * **Tumor surgery**: low-grade gliomas, meningiomas invading the cortex * **Vascular lesions**: AVMs, cortical aneurysms * **Access to deep structures**: * Transsylvian approach * Transcortical approach * Transplanum–transpolfar approaches (endonasal) * **Epilepsy surgery**: selective amygdalohippocampectomy, disconnections ===== 🛡️ Advantages ===== * Preserves **cortical and vascular integrity** * Reduces risk of **neurological deficits** * Minimizes **postoperative seizures** * Allows **safe retraction and exposure** of eloquent areas ===== ⚠️ Risks and Considerations ===== * Risk of damaging **subpial vessels** (possible infarcts) * Infiltrative or inflammatory lesions may **obscure the subpial plane** * Requires **microsurgical precision** and excellent visualization ===== 🧠 Key Anatomical Notes ===== * The **pia mater** contains pial vessels and marks the outermost layer of the cortex. * Subpial dissection preserves **arachnoid and vascular layers** while accessing lesions directly beneath the cortical surface. ===== 📚 References ===== * Yasargil MG. ''Microneurosurgery''. Volumes I–IV. Thieme. * Berger MS, Hadjipanayis CG. Surgical techniques for infiltrating gliomas. ''Surg Neurol''. 2007. * Spetzler RF, et al. Use of subpial planes in eloquent cortex surgery. ''Neurosurgery''. 1992.