Figure 4: Intra-operative photographs showing operative steps (B) small amount of the CSF was let out through a small opening in the sac, (C) note the reduction in the size of swelling, (D) sac was opened, (E) base of sac was defined, note the presence of large vessels near to the opening in the skull, (F and G) redundant brain tissue was excised while preserving the large vessels, (H and I) dura and skin were closed.