Safety and Efficacy of the BTL-043 and BTL-899 Devices in Alleviating Back Pain

The study will evaluate the clinical efficacy and performance of the BTL-043 and BTL-899 devices for alleviating back pain. It is a prospective, multi-center, open-label, single-arm study. Subjects will be required to complete four (4) treatment visits and two (2) follow-up visits. At the baseline visit, the Oswestry Disability Index (ODI), Visual Analogue Scale for pain (VAS), the Quebec Back Pain Disability Index (QBPDS), palpation of the treatment area, Fingertip-to-Floor-Flexion (FTFF) test, and Lateral FTFF test will be performed. Additionally, two-dimensional (2D) photographs of the subject's posture from the left and right profile will be taken, their Fitzpatrick skin type assessed, and the subject's weight and height will be recorded. The treatment administration phase will consist of four (4) treatment visits, delivered 5-10 days apart. During each treatment visit, subjects will receive treatments with both study devices, BTL-043 and BTL-899, consecutively, one immediately after the other. Therapy time will be set to 30 minutes for each treatment with each study device. After the last treatment, the subjects will complete the ODI, QBPDS, the Therapy Comfort Questionnaire (TCQ), and the Subject Satisfaction Questionnaire \& Quality of Life Questionnaire (SSQ \& QoL), along with the VAS, undergo palpation of the treatment area, FTFF, Lateral FTFF, weight and height measurements, and 2D photographing. During the 1-month and 3-month follow-up visits, the subjects will complete the SSQ \& QoL, the ODI, QBPDS, VAS, undergo palpation of the treatment area, FTFF, Lateral FTFF, weight and height measurements, and 2D photographing. Safety measures will include documentation of adverse events (AE), which will be assessed after each procedure and at all follow-up visits.

Inclusion Criteria: * Age 22 years and older * Voluntarily signed an informed consent form * Subject is willing to comply with study instructions and to return to the clinic for the required visits * Willingness to adhere to and continue pre-enrollment pain management plan * Subjects willing and able to maintain their regular (pre-procedure) diet, exercise, and therapy regimen without causing significant changes during study participation * Subject willing and able to abstain from partaking in any new treatments other than this study procedure to treat back pain * Women of child-bearing potential\* are required to use birth control measures during the whole duration of the study \*Women of childbearing potential are defined as any female who has experienced menarche and who is NOT permanently sterile or postmenopausal. Postmenopausal is defined as 12 consecutive months with no menses without an alternative medical cause. Exclusion Criteria: * Major systemic diseases - e.g. uncontrolled Diabetes mellitus, systemic lupus erythematosus * Ongoing pregnancy, postpartum and nursing period * Photosensitivity, medications affecting sensitivity to light * Tattoos or other highly-pigmented regions in the treated area * Corticosteroids or injections of the treated area within the last 3 months, long-term corticosteroids use * Anticoagulant therapy, bleeding disorders * Hemorrhagic conditions in the treated area * Application within 4 to 6 months after radiotherapy * Known or suspected malignancy, history of cancer or any type of malignancy * Febrile conditions, serious illness, chronic infection * Epilepsy and tendency to seizures * Sensory loss in the treatment area * Deep vein thrombosis * Electronic implants (such as cardiac pacemakers, defibrillators and neurostimulators) * Metal implants, bone fixation hardware, external metallic objects or electrical devices in the vicinity of the treated area * Drug pumps * Pulmonary insufficiency * Renal insufficiency * Cardiovascular diseases * Disturbance of temperature or pain perception * Septic conditions and empyema * Acute inflammations * Systemic or local infection such as osteomyelitis and tuberculosis * Contagious skin disease * Elevated body temperature * Graves' disease * Women using birth control in the form of a metal-containing intrauterine device (IUD) * Swollen or neoplastic tissues, space occupying lesions or skin eruptions in the treated area