Extradural anterior clinoidectomy as an alternative approach for optic nerve decompression: anatomic study and clinical experience

We introduce pterional craniotomy extradural anterior clinoidectomy as a new alternative approach for optic nerve decompression in patients with traumatic optic neuropathy. Intracranial structures pertinent to pterional craniotomy extradural anterior clinoidectomy were carefully studied in 10 dry craniums and 10 cranial bases with dura mater. Important parameters of these structures were measured. Stepwise dissections simulating pterional craniotomy extradural anterior clinoidectomy were performed in 20 cadaver heads bilaterally. Pterional craniotomy extradural anterior clinoidectomy was then applied to 12 patients (13 eyes) with traumatic optic neuropathy and severe visual dysfunction. The anatomic features and their variations of optic canal, ophthalmic artery, falciform ligament, and Zinn's ring (annular tendon) were studied and measured in detail. Extensive opening of the optic canal and optic nerve sheath was successfully achieved in all 12 patients without major surgical complications. Significant visual acuity improvement occurred in eight (nine eyes) out of our 12 patients after surgery. The surgical techniques and advantages of pterional craniotomy extradural anterior clinoidectomy for optic nerve decompression are presented and discussed in detail. Pterional craniotomy extradural anterior clinoidectomy is a promising new alternative approach for optic nerve decompression in patients with traumatic optic neuropathy.