Patient-reported and functional outcomes following ReActiv8 implantable neurostimulation

This is a single-arm study looking at longitudinal changes in function and patient-reported outcomes (PROMs) following treatment for chronic mechanical low back pain using ReActiv8 restorative neurostimulation. It is important to note that the ReActiv8 device is available commercially, and patients may choose to undergo device implantation outside of this study. However, if patients choose to participate in the study, they will be assessed pre-procedure (baseline), 8-weeks, 27-weeks, and 54-weeks post-implantation. The procedure: A neurosurgeon is responsible for the implantation of the device. The ReActiv8 leads are introduced under fluoroscopic visualization using a needle, guide wire, and delivery sheath with dilator. Leads are placed bilaterally, with the electrodes placed adjacent to the medial branch of the dorsal ramus as it crosses the transverse process at L3. Leads are tunnelled subcutaneously between the lead implant incision and the IPG pocket. The IPG is placed in a subcutaneous pocket in a location deemed appropriate by the implanting physician, considering the patient’s ability to reach the IPG location for initiation of stimulation with the Activator. The device: The IPG delivers electrical stimulation pulses to the nerves that activate the lumbar multifudus muscle. Using the wireless remote, the individual is able to start, pause, or stop a session of electrical stimulation. Participants are required to activate the device for 30 minutes, twice a day while lying down. There is no endpoint for the stimultation sessions. The functional assessments: A Sports Scientist is responsible for the pre and post-implantation performance measures. These assessments will occur at BackSpace Clinic, Brisbane Private Hospital and will take 30 minutes to complete. These include a 30-second Sit-to-Stand, Timed-Up-and-Go walking test, centre of pressure measurements using a force plate and flexion, extension and rotation angles using wearable motion sensors. The ultrasound: A sonographer performs the radiographic assessment on participants at Brisbane Private Imaging, Brisbane Private Hospital. B-mode ultrasound will capture transverse images of the multifidus muscle at each level from L1-S1 on both sides. Passive muscle stiffness of the multifidus will be assessed with shear wave elastrography at each level between L1-S1 on each side. As a reference figure, transverse images of the achilles tendon will be captured. It is anticipated that the imaging series will take 20 minutes. The PROMs: The researcher will email seven x PROMs to the patient in advance of their appointment via an online link. The seven questionnaires includes the: Visual Analogue Scale, Oswestry Disability Index, PROMIS-29, Fear of Movement Questionnaire, Pain Self-Efficacy Questionnaire, Quality of Life and the Graded Chronic Pain Scale. Completeting all of the questionnaires will take approximately 20 minutes.