experience, anatomic consideration of the aneurysm, and the status of the aneurysm (ruptured or unruptured). Low-lying, broad-neck, and ruptured distal internal carotid artery aneu- rysm may be obliterated more safely by pterional approach. The lateral supraorbital approach provides a longer route to the basilar tip and a lesser exposure volume, and consequently needs more frontal lobe retraction before reaching the chias- matic and carotid cisterns7). However, in the lateral supraorbital approach, the temporal muscle splitting is limited to its superi- or and anterior part, because the small skin incision never de- scends in front of the ear to the level of the zygomatic arch; thus, any injury of the upper branches of the facial nerve can be avoid- ed by detaching the one layer skin-galea-muscle flap from the bone. Temporalis muscle atrophy caused by denervation, loss of blood supply or inappropriate muscle tension, may be serious cosmetic and functional complications5). Furthermore, the small craniotomy made with only one burr hole in the LSO approach can shorten the overall operation time and reduce craniotomy- related complications, such as CSF leak, postoperative epidural hematoma and infection; the size of craniotomy, of course, is sufficient to reach the whole anterior part of the Circle of Willis, sellar, and suprasellar region3). In this study, the operation time in the LSO approach was sig- nificantly shorter than that of the pterional approach. For the pterional approach, the long and downward extending skin in- cision, more splitting of the temporalis muscle, large cranioto- my with several burr holes and drilling of the sphenoid ridge could increase both operation time and surgical morbidity3,10). The limitation of this study is that we did not focus on the postoperative cosmetic and functional results, such as chewing discomfort, temporal muscle atrophy and hyposmia, which may influence the quality of life of our patients. CONCLUSION In our experience, the lateral supraorbital approach provides adequate exposure of the lesion and allows safe neurosurgical Lateral Supraorbital Approach | KC Cha, et al. manipulation, with much shorter operation time and much smaller craniotomy, thereby decreasing surgical morbidity. Thus, the lateral supraorbital approach for clipping of unruptured in- tracranial aneurysm could be a good alternative to the classic pterional approach. References 1. Figueiredo EG, Deshmukh P, Nakaji P, Crusius MU, Crawford N, Spet- zler RF, et al. : The minipterional craniotomy : technical description and anatomic assessment. Neurosurgery 61 : 256-264; discussion 264-265, 2007 2. Figueiredo EG, Deshmukh V, Nakaji P, Deshmukh P, Crusius MU, Crawford N, et al. : An anatomical evaluation of the mini-supraorbital approach and comparison with standard craniotomies. Neurosurgery 59 : ONS212- ONS220; discussion ONS220, 2006 3. Hernesniemi J, Ishii K, Niemelä M, Smrcka M, Kivipelto L, Fujiki M, et al. : Lateral supraorbital approach as an alternative to the classical pteri- onal approach. Acta Neurochir Suppl 94 : 17-21, 2005 4. Mori K, Yamamoto T, Nakao Y, Oyama K, Esaki T, Watanabe M, et al. : Lateral supraorbital keyhole approach to clip unruptured anterior com- municating artery aneurysms. Minim Invasive Neurosurg 51 : 292-297, 2008 5. Oikawa S, Mizuno M, Muraoka S, Kobayashi S : Retrograde dissection of the temporalis muscle preventing muscle atrophy for pterional crani- otomy. Technical note. J Neurosurg 84 : 297-299, 1996 6. Park JC, Hamm IS : Cortical osteotomy technique for mobilizing the temporal muscle in pterional craniotomies. Technical note. J Neurosurg 102 : 174-178, 2005 7. Salma A, Alkandari A, Sammet S, Ammirati M : Lateral supraorbital approach versus pterional approach : an anatomical qualitative and quantitative evaluation. Neurosurgery 68 : ONS364- ONS372, 2011 8. Steiger HJ, Schmid-Elsaesser R, Stummer W, Uhl E : Transorbital key- hole approach to anterior communicating artery aneurysms. Neurosur- gery 48 : 347-351; discussion 351-352, 2001 9. van Lindert E, Perneczky A, Fries G, Pierangeli E : The supraorbital key- hole approach to supratentorial aneurysms : concept and technique. Surg Neurol 49 : 481-489; discussion 489-490, 1998 10. Wen HT, de Oliveira E, Tedeschi H, Andrade FC, Rhoton AL : The pterional approach : surgical anatomy, operative technique, and ratio- nale. Oper Tech Neurosurg 4 : 60-72, 2001 11. Yasargil MG, Fox JL : The microsurgical approach to intracranial aneu- rysms. Surg Neurol 3 : 7-14, 1975 337