Transplanum Polare Approach [Neurosurgery Wiki]

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====== Transplanum Polare Approach ======

see also [[Transplanum polare approach to the anterior mesiotemporal region]]

The **transplanum polare approach** is a microsurgical skull base technique used to access midline anterior cranial fossa lesions, particularly those involving the suprasellar region and anterior third ventricle.

===== Indications =====
  * Craniopharyngiomas
  * Tuberculum sellae and planum sphenoidale meningiomas
  * Hypothalamic hamartomas
  * Pituitary macroadenomas with suprasellar extension (select cases)
  * Rathke’s cleft cysts with suprasellar component
  * Optic pathway/hypothalamic gliomas

===== Surgical Anatomy =====
  * Planum sphenoidale
  * Tuberculum sellae
  * Optic nerves and optic chiasm
  * A1 segments of anterior cerebral arteries
  * Lamina terminalis (may be opened for third ventricle access)
  * Olfactory nerves
  * Suprasellar cistern

===== Surgical Technique =====
  * **Position:** Supine, head slightly extended and fixed
  * **Craniotomy:** Bifrontal craniotomy, often with orbital roof osteotomies
  * **Exposure:** Subfrontal or interhemispheric corridor to the anterior skull base
  * **Brain relaxation:** CSF drainage via lumbar drain or cisternal opening
  * **Bone removal:** Drilling of orbital roofs and planum sphenoidale for better access
  * **Dissection:** Microsurgical dissection around critical neurovascular structures
  * **Optional:** Opening the lamina terminalis to reach the third ventricle

===== Advantages =====
  * Direct midline access to anterior skull base and suprasellar region
  * Wide bilateral exposure
  * Useful for large or complex tumors not accessible endonasally

===== Disadvantages and Risks =====
  * Anosmia (olfactory nerve injury)
  * Frontal lobe contusion from retraction
  * Venous infarction (superior sagittal sinus or bridging veins)
  * CSF leak if reconstruction is inadequate
  * Cosmetic issues if frontal sinus is breached

===== Alternatives =====
  * Endoscopic endonasal approach (EEA)
  * Pterional or orbitozygomatic approaches
  * Transcallosal interforniceal approach (for deeper third ventricular lesions)

===== Notes =====
  * This approach is ideal when lesions extend above the chiasm or when endonasal access is contraindicated.
  * Reconstruction of the skull base is critical to prevent postoperative CSF leaks.