Although cluster headache (CH) has been known for many years, major CH surveys with emphasis on pain localization are rare. 1-4 Results from previous international cross-sectional surveys on CH describe demographics, 2,5,6 clinical characteristics including symptoms and personal burden, 2,4,6-9 and diagnostic and therapeutic challenges. 8,10-12 Current pharmaceutical management of CH 13-15 including acute and preventive treatment involves substances 13,16 which, especially when used in high doses over long

Background and Objective:Applying local treatments like neuromodulation or injections for cluster headache, requires exact knowledge of the anatomical structures and pain topography. However studies with emphasis on exact pain localization are rare although local treatments are increasingly used for patients in whom systemic pharmacotherapy is ineffective or contraindicated. Here, survey results with emphasis on exact pain location in cluster headache attacks for onset of pain, peak pain and radiation of pain, are presented. Methods: Data from 631 respondents were collected for 23 months using an online survey composed of 117 questions on pain location, epidemiology, and clinical features. 5260 datapoints on 44 pain locations were analyzed.Results: There is a periorbital concentration of pain during onset and peak phases of attacks. Pain locations outside the periorbital region were reported more frequently during radiation when compared to the onset and peak of attacks. Dorsal (occipital/nuchal) pain is more frequent during onset and radiation compared to peak: onset pain (13%) vs. peak pain (6%), p < 0,001. Pain radiation (22%) vs. peak pain (6%), p < 0,001. There is no significant difference in dorsal pain frequencies for pain radiation (22%) vs. onset (13%), p = 0,552. Furthermore, single pain spots differ significantly in frequency during the three attack phases.Conclusions: Analysis of the pain location data shows phase specific frequencies and distributions of pain location during the three stages of a cluster headache attack. Single pain spots differ significantly in frequency during the three attack phases. Dorsal pain is more frequent during onset and radiation, compared to peak. Extra-orbital pain locations are more frequent during pain radiation. These findings will help to better understand cluster headache and might help to identify further target structures for local treatments.

Background The consensus for the optimal treatment strategy for chronic Achilles tendinopathy (AT) is still debated and treatment options are limited. This results in a significant medical need for more effective treatment options. Objective The aim of this study is to investigate the therapeutic effects of percutaneous bioelectric current stimulation (PBCS) on AT. Methods A multicenter, randomized, double-blind, placebo-controlled clinical trial will be conducted. A total of 72 participants with chronic (ie, >3 months) midpoint AT will be randomized and receive four PBCS sessions—either verum or placebo—over 3 weeks. Both groups will complete daily Achilles tendon loading exercises in addition to the intervention. Evaluation sessions will be completed at baseline and during the intervention (weeks 0-3). Self-reported outcome measures will be completed at follow-up at weeks 4, 12, 26, and 52. The primary outcomes are the Victorian Institute of Sports Assessment–Achilles questionnaire scores and statistical evaluation of intraindividual differences between baseline and 12-week evaluations after initial treatment of verum therapy compared to control. Secondary outcomes will assess Pain Disability Index scores; average pain, using the 11-point Numeric Rating Scale; return to sports; and use of emergency medication. Results The study began in May 2021. As of October 2022, we randomized 66 out of 72 participants. We anticipate completing recruitment by the end of 2022 and completing primary data analysis by March 2023. Conclusions The study will evaluate the effects of PBCS on pain, physical function, and clinical outcomes. Trial Registration German Clinical Trials Register DRKS00017293; https://tinyurl.com/mvz7s98k International Registered Report Identifier (IRRID) DERR1-10.2196/40894