1. Raak C 1, Scharbrodt W 2,Weninger A 1, Berger B 1,Ostermann T 1 1.Institute of Integrative Medicine, Witten/Herdecke University, Gerhard-Kienle-Weg 4, 58313 Germany 2.Integrative Neuromedicine, Witten/Herdecke University, Gerhard-Kienle-Weg 4, 58313 Germany HyPOS - Hypericum perforatum to improve post-operative Pain Outcome after monosegmental Spinal microdiscectomy Background: Spinal disk herniation is one of the most common degenerative diseases of the spine. Many patients undergoing surgery suffer on nerval pain known as memory pain at the 3 rd day post op. In such situations pain often radiates to different areas of the spine and might spread to different parts of the whole body. In monosegmental spinal stenosis surgery this results in the prescription of high doses of opioid medications. Hypericum perforatum is known as a remedy for lancinating pain especially when nerval damage is involved. Reduction of pain after application of Hypericum perforatum was observed in studies i.e. in neuropathic pain, after knee ligament reconstruction or after tooth extraction. This study aimed at investigating whether Hypericum perforatum C200 leads to a decrease of post operative pain and a decrease of pain medication compared to placebo. Material and Methods: This is a monocentric double blind, randomized placebo controlled trial conducted in the Department of Neurosurgery at the Community Hospital Herdecke. 100 Study participants will be recruited from in-patients undergoing elective monosegmental Spinal stenosis surgery. From this cohort patients are randomly selected into homeopathic treatment plus usual pain management vs. usual pain management and placebo. The primary clinical outcome is pain reduction after three days of inpatient care. Based on moderate effect sizes and allowing dropout rate of 15%, it is estimated that 50 people will be needed for both study arms to detect a minimal clinical difference in pain reduction at 80 percent power and 5 percent significance. Statistical analysis is done by intention to treat by means of a covariance model with adjustment for baseline values and patient expectation. Status: This trial has received ethical approval and has been reviewed by the Federal Institute for Drugs and Medical Devices (BfArM) and has just been initiated. Results are expected in 2016. Trial registration: EudraCT: 2013-001383-31 Fig 3: Flow chart of patient recruitment of the HyPoS-study Contact: Christa Raak, BSc Institute of Integrative Medicine, Witten/Herdecke University, 58313 Herdecke, GERMANY, E-Mail: christa.raak@uni-wh.de Fig 1: Spinal disk herniation Fig 2: Hypericum perforatum, (St. John´s Wort) Aim of the study: To investigate the effect of Hypericum perforatum C200 in postoperative pain management. Outcome primary: Pain reduction of subjective pain on VAS 100 mm at the 3rd day post OP Outcome secondly Post op comsumption of analgetics Pain reduction of subjective pain on VAS 100 mm at the 5th day post OP Decrease of sensory and affective pain perception (SES) Discussion: We expect that this study will generate immediate benefits with low risk in patients undergoing monosegmental spinal stenosis surgery in those patients treated homeopathically. Moreover results may contribute to improve post-operative pain management strategies. Anamnesis Informing Consent Inclusion Surgery Hypericum Initial visit R Placebo Initial visit Follow up visits Final visit T -1 T 0 T 1 T 2-4 T 5