1. Post. Circulation aneurysms M.MOLAVI MD

7. 10-15% of all intracranial aneurysms Most challenging aspect of cerebrovascular surgery Situated close to the BS

8. Ans. Arising from intracranial VA (PICA) Ans. of vb junction Ans. of AICA & mid basilar trunK Ans. of SCA Ans. of Basilar tip Ans. of PCA

9. Major challenges of treating VB ans. Achieving adequate exposure Avoiding cranial nerves inj. Maintaining vascular integrity

11. VA, BA, PICA, AICA, SCA,& PCA perforating branches supply the Ant. & Lat, aspect of BS 2/3 of perforating branches of BA arise from cephalic portion; thus the caudal portion is the prefered site for cross- clamping

14. CLINICAL PRESENTATION Headache Coma BS symptoms 3 rd nerve palsy (basilar-SCA an. Rupture) 6 th nerve palsy( basilar – AICA an.) Lower cranial nerve dysfunction ( vertebral & vertebro-basilar an.) Unruptured ans. May cause dysfunction of BS & cranial nerves by local effects of the mass lesion

15. VB Anatomy

16. DIAGNOSIS CT MRI MR Angiography Standard 4-vessel angiography DSA

19. Surgical Considerations Surgical clipping Wrapping Trapping Ligation of VA extra or intracranially Endovascular techniques ( Balloons or coils)

26. General principles for operation Careful choice of the appropriate approach Adequate positioning Maximal decompression of brain w CSF diversion & drugs Use of magnification Thorough intraoperative monitoring Wide selection of clips

27. Intraoperative rupture prevention Systemic hypotension Temporary clipping of the parent vessel or Temporary balloon occlusion Deep hypothermia Cardiac arrest

28. Surgical approaches Suboccipital app: entire intracranial VA, PICA, & lower part of BA up to the level of AICA Sub temporal or Trans oral app: ans. Along the upper2/3 of the clivus Subtemporal transtentorial or suboccipital app: mid basilar trunk ans. & AICA origin ans.