World Skull Base 2016 CS1-1-1 Venous Anatomy for C-P angle reduction of cyst contents was associated with Surgeries marked improvement of the symptoms. However, two exceptional young cases showed strangulation Toshio Matsushima of the affected facial and abducent nerves by the Neuroscience Center, Fukuoka Sanno Hospital, Japan tumor capsule whose preoperative dysfunction did not improve after surgery in spite of meticulous I am going to present the surgical anatomy of the microsurgical removal of the lesion. Involved facial following two venous systems, which is very useful nerve showed marked nerve atrophy distal to the for the C-P angle surgeries. One is the superior strangulation site. petrosal vein (SPV) in the upper C-P angle because In this paper, surgical technique and their surgical its tributaries often act as an obstacle during outcome for CPA epidermoid cyst will be presented surgery, and when sacrificed serious postoperative with focuses on characteristics for the cases with complications may occur. The other is the posterior the strangulation mechanism. condylar emissary vein, which can be used as an intraoperative anatomical landmark during removal of the lateral foramen magnum, especially through trans-condylar fossa approach. CS1-1-3 Surgical resection of cerebello- In the former its tributaries and the classification pontine epidermoid cysts; based on the tributaries will be explained. Since Outcome & complications the most dangerous tributary of the SPV is the vein Hisham A. Aboul-Enein， Ahmed H. Farhoud ， of the cerebellopontine fissure, the vein will be Ihab H. Zidan ，Nabil A. Rahman explained in detail. Anatomical knowledge of the Department of Neurosurgery, Alexandria University, Egypt SPV drainage pathways is also very important to safely expose lesions in the upper C-P angle. The Background, Epidermoid cyst is a congenital slow superior petrosal sinus is the final SPV drainage growing lesion. 32 patients were operated upon for pathway, and the sinus has sometimes a partial microsurgical excision of CPA epidermoid cysts, defect. The superior petrosal sinus is separated between 2003 and 2013. We report a thorough Session Concurrent into anterior and posterior parts based on the analysis of these patients as regards the adherence draining point of the SPVs. Careful preoperative of the secretory capsule and the clinical outcome assessment of venous drainage pathways will be when radical surgical removal was attempted. emphasized. Material and methods, the age ranged between 20 In the latter, variations of the posterior condylar and 65 years. All patients suffered from symptoms emissary vein and the posterior condylar canal will of c-p angle syndrome or signs of posterior fossa be presented. Then, it will be explained how to be tumor. All patients were operated through a found and how to be used as an anatomical retromastoid approach. Results, Total resection of landmark during the trans-condylar fossa the epidermoid cysts was accomplished in 26 cases, approach. and subtotal resection in 4 cases. Two patients underwent partial resection. 2 patients showed deteriorations of the pre-operative neurological CS1-1-2 Cerebellopontine angle status. A persisting neurologic deficit was observed epidermoid cysts: New in two cases (hearing loss, dysphonia). Two patients pathogenesis of cranial nerve were lost in the follow-up period. Conclusions, Epidermoid cyst is a benign tumor. Total resection dysfunction and their surgical is the ideal treatment, but surgeons have to be outcome aware of the critical complications that might occur Mituhiro Hasegawa when attempting total excision especially in cases Department of Neurosurgery, Fujita Health University, Japan where the capsule is adherent to the brainstem. Epidermoid cysts are rare intra-cranial tumors. Forty percent of them are located in CS1-1-4 Surgical management of cerebellopontine angle (CPA), and show various intracranial epidermoid tumors; cranial nerve (CN) dysfunction. Although several Lessons learned from 334 cases mechanisms for the CN dysfunction have been over 3 decades proposed, no direct evaluation has been done. In Goh Inoue 1,2，Takanori Fukushima1 ， this case series, pathophysiology of cranial nerve 1 1 dysfunction in CPA epidermoid cysts was Allan H Friedman ，John Sampson ， Kuniaki Tanahashi1 ，Peter Grossi 1 evaluated, and a new mechanism of capsule 1Department of Neurosurgery, Duke University, USA， strangulation was proposed. Twenty-five cases with 2Department of Neurosurgery, Tokai University, Japan CPA epidermoid cysts (2005-2016) were approached through retrosigmoid route except two cases Surgery of intracranial epidermoid tumor is a treated with anterior petrosal route. Mass difficult challenge. Traditionally, because of 167 World Skull Base 2016 adherence to surrounding neurovascular CS1-1-7 Surgical management of structures, subtotal resection leaving the adherent trigeminal neuroma capsule, was advocated. More recently, some Chang J. Kim experts reported radical total resection, including capsule dissection, has been advised to for cure. Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Korea Herein, we present our experience with 334 cases of intracranial epidermoid tumors wherein complete resection of the tumor including the Trigeminal neuroma (TN) may arise from any part capsule was attempted in all cases. of trigeminal nerve, from cisternal part to its distal This is the largest series, to date, of patients branches. TN may involve any compartment, operated for intracranial epidermoid tumors. including posterior fossa, middle fossa, or along its Distribution of the tumor, surgical results, distal branches, or may involve multiple complication avoidance, and long-term follow up compartments. They produce various shapes will be discussed. involving in various locations. 56 patients with TN were treated until recently. Tumors were classified as follows: tumor confined to the middle fossa (10 cases, 17.6%), tumor CS1-1-5 Surgical management of confined to the posterior fossa (7 cases, 12.5%), cerebello-pontine angle tumor involving both middle and posterior fossae (7 epidermoid tumors cases, 12.5%), tumor confined predominantly to the Milind Dunakhe middle fossa with posterior fossa extension (11 Department of Neurosurgery, Dunakhe Hospital Pvt. Ltd., India cases, 19.6%), tumor confined predominantly to the posterior fossa with middle fossa extension (13 OBJECTIVES: To evaluate the efficacy of various cases, 23.2%), tumor confined predominantly to the modes of surgical management of CPA epidermoids middle fossa with extracranial extension (4 cases, with regard to removal and preservation of the 7.2%), and tumor predominantly occupy the middle Cranial Nerves.To study the role of endoscopy in fossa and also involve the posterior fossa and assessing excision of Epidermoid. intracranial branch (4 cases, 7.2%). Various METHODS: From 2009 to 2016, 42 patients were surgical approaches were chosen according to the admitted in Dunakhe Hospital Aurangabad. All tumor type. Gross total resection was achieved in patients underwent CT and MRI of brain and were 91.1% of patients. operated by Retrosigmoid approach.Endoscopy was Details of clinical presentation and surgical used to assess the excision.Follow up was based on outcomes will be presented. outpatient imaging. RESULTS: Patients presented with Headache (33 cases), cerebellar signs(4 cases), Trigeminal CS1-2-1 Microsurgery of giant neuralgia (1 case),facial palsy ( 1 case), aneurysms Hydrocephalus (9 cases).The mean duration of Basant K. Misra symptoms was 20 months.The mean follow up was Department of Neurosurgery, P. D. Hinduja National Hospital 18 months. 1 patient died due to aseptic and Medical Research Centre, India meningitis.Compared with preoperative clinical status 83% improved, no patient had cranial nerve deficit post operatively. CONCLUSION: Meticulous surgical technique is important to achieve safe and effective total excision. To avoid recurrence all corners of CPA CS1-2-2 Skull base approaches for should be checked.Endoscope assisted excision vascular lesions helps in total excision of tumor. Amir R. Dehdashti It is very difficult for single surgeon to go till the Department of Neurosurgery, Northshore University Hospital, level of total excision due to limited resources. USA CS1-1-6 Development of TED scale for the surgery of petroclival tumors Han K. Kim Department of Neurosurgery, Bundang Jesang General Hospital, Korea 168 World Skull Base 2016 CS1-2-3 Analysis of supraorbital keyhole long straight clips are commonly used, usually 2 approach in groups of middle clips in parallel fashion. Intraoperative Doppler and ICG are useful in order to check the flow of the cerebral artery(MCA) parent artery and no flow into the aneurysm. aneurysms and anterior Multiple syringes for suction should be prepared to communicating artery(AcoA) perform continuous suctioning procedure. aneurysms Ipsilateral ischemic complication occurred only in Chae H. Lee ，Chan Y. Choi ，Do H. Kim one case and visual symptoms improved Department of Neurosurgery, Ilsan Paik Hospital, College of postoperatively in 9 out of 15 cases with Medicine, Inje University, Korea preoperative visual disturbance. Video is used to demonstrate our setting, procedure OBJECT:The supraorbital keyhole approach via an and selection of clips. eyebrow skin incision provides a method for the minimally invasive clipping of aneurysms located in the circle of Willis, but has disadvantages for CS1-2-5