Plenary Oral Presentations - Macquarie University Hospital

16 th International Meeting of the Leksell Gamma Knife ® SocietyMarch 2012, Sydney, AustraliaFU-62Neuromodulation in Gamma Knife Surgery forFunctional Disorders: Current and Future1,2Motohiro Hayashi, 1 Noriko Tamura, 1,2 Shoji Yomo, 1 Manabu Tamura,1Masahiro Izawa, 1 Mikhail Chernov, 1 Yoshikazu Okada1Tokyo Women’s Medical University2Saitama Gamma Knife Center, Sanai Hospital, Saitama, JapanObjective: Gamma knife surgery (GKS) has been applied as a treatment for functional disorders, andthe clinical results are preferable and acceptable to be evaluated. However, the critical action mechanismis not known yet. Among of them, we suspected it should be destructive change due to GKS fortremor and epilepsy caused by hypothalamic hamartoma. On the other hand, we also suspected thatintractable pain and mesial temporal lobe epilepsy(MTLE) might not be triggered by the destructivechange according to postoperative clinical course. We will report our clinical results to demonstrateneuromodulative change which might provide the patients cure.Methods: 130 patients with essential trigeminal neuralgia(TGN), 21 patients with cancer pain(CP),24 patients with thalamic pain syndrome(TPS), and 4 patients with MTLE were registered in ourretrospective study. All patients could be followed up at least 3 years excluding the cases with cancerpain. In TGN, the target should be the trigeminal nerve at retrogasserian region with 90Gy at maximumdose using single shot of 4 mm collimator. In CP and TPS, the target should be the anterior lobeof the pituitary gland with 140-180Gy at maximum dose using single shot of 8 mm collimator. InMTLE, the target should be the archeocortex and entrhinal cortex, whose target volume should beranged between 7 and 8cc, with 22-24Gy at marginal dose using 4 and 8 mm collimators.Results: In TGN, 98% of initial electric discharge free, 66% of complete pain free at the last followup, and 24% of significant complication (facial numbness). In CP, 90.5% of significant pain reductionwithout significant complication. In TPS, 71% of significant pain reduction without significantcomplication excluding 30% of endocrinological impairment. In MTLE, 75% of significant seizurecessation without significant complication excluding MR morphological changes were seen.Conclusions: The true action mechanism of these presenting disease could not be elucidated yetwithout some hypothesis that GKS might provide something of neuromodulative effect to the patients,according to postoperative clinical phenomena. We would like to have much more experience andperform basic research to prove our hypothesis.20