Aldo Liguori; Jacob Juel; Stefano Liguori; MassimilianoValeriani, Carina Graversen, MSc;Søren S. Olesen; Asbjørn M. Drewes

（1 Istituto Paracelso, Rome, Italy; 2 Department of Anatomic, Histologic, Forensic Medicine and Locomotor System Sciences, Faculty of Pharmacy and Medicine, Sapienza University; 3 MechSense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark; 4Department of Neurology, Paediatric Hospital Bambino Gesù, Rome, Italy;  4 Center for Sensory-Motor Interaction, Department of Health Science and Technology, Faculty of 

Medicine, Aalborg University, Aalborg, Denmark）

Abstract：Objective. Acupuncture is increasingly used as an alternative to medical therapy for various painconditions. To studythe effect of acupuncture in experimental and clinicalstudies, a control  condition  with  sham  acupuncture  isneeded.  However,  as  such  models  have  not  been establishedin assessment of acupuncture effect against visceral pain,this study aimed to validate a new method for blinded shamacupuncture in experimental rectal pain.Materials and methods.Fifteen subjects underwent a sequence of eithersham or real acupuncture in randomized order. In the shamarm, a hollow inner tube with a sharp tip was fitted into anouter tube and subjects were blinded to the stimulations.Before and after the intervention, pain was induced by rectalstimulation with  an  inflatable  balloon distended until  thesubjects’ pain  threshold  was  reached. The  resting electroencephalogram  (EEG)  was  quantified  by  spectral  power  analysisto  explore  the  central nervous system effects objectively.Additionally, after the second study day, the subject wasasked to indicate the sequence of interventions.Results. A significant increase in rectal balloon volume was observed after sham 12±21 mL (P=0.049) and real acupuncture17±30 mL (P=0.046). However, the change in volume wasnot different between groups (P  = 0.6). No differences in EEGspectral power distributions  between  sham  and  real  acupuncturewere  seen  (all  P>0.6).  The  correct sequence of sham andacupuncture was indicated by 36% of the subjects (P=0.4).Conclusions.  The presented sham procedure provides avalid method for blinding of “sham acupuncture” and maybe used in future blinded controlled trials of acupuncture forvisceral pain. 

Key  words:  acupuncture,  sham-controlled,  sham  acupuncture,  experimental  visceral  pain, abdominal pain, EEG ,spectral power analysis.