Vagus Nerve Stimulation for Treating Adults With Severe Fibromyalgia
Condition: Fibromyalgia
MeSH terms: Fibromyalgia; Myofascial Pain Syndromes
Study type: Interventional
Phase: Phase 1

Summary: 
      Fibromyalgia syndrome (FMS) is a long-term disorder that is characterized by widespread body
      pain and tender points in joints, muscles, tendons, and other soft tissues. Other symptoms
      associated with the disorder include fatigue and depression. The cause of FMS is unknown, and
      conventional treatments are often unsuccessful in adequately relieving pain. For people with
      severe, unrelenting pain, which is referred to as refractory FMS, opioid maintenance therapy
      may be an option, but it comes with the dangerous potential of addiction and is therefore
      avoided if possible. Vagus nerve stimulation (VNS), in which a nerve located in the neck
      receives electrical input, may be an option for providing pain relief. The purpose of this
      study is to determine the safety, tolerability, and effectiveness of VNS as a treatment for
      people with refractory FMS.
    

Detailed description: 
      FMS affects about 5% of the general population and occurs most often in women between the
      ages of 20 and 50 years old. Overall, more than 80% of FMS patients report that pain is the
      primary symptom that limits their ability to work, about 30% of patients are disabled, and
      about 45% collect Social Security Disability insurance. Conventional treatments, which
      include pharmacological and behavioral interventions, fail to provide adequate pain relief in
      more than half of FMS patients, strongly suggesting the need for improved treatment options.

      One such option is a treatment called vagus nerve stimulation (VNS), in which short bursts of
      electrical energy are directed into the brain by way of the vagus nerve. The vagus nerve is a
      cranial nerve that originates in the brainstem, travels through the neck, and then continues
      down through the thorax and abdomen. The nerve acts as both a sensory and motor nerve, and it
      can regulate several brain areas involved in pain and emotional processing. With VNS, a small
      battery device is surgically implanted under the skin, usually under the chest, and provides
      the necessary electrical energy for stimulation. Although VNS has been FDA approved for some
      forms of epilepsy and depression, it has yet to receive FDA approval for FMS. Also, it is
      unknown whether the safety and tolerability profile of an FMS patient receiving VNS is the
      same as that of a patient with epilepsy or depression who is receiving VNS. The purpose of
      this study is to determine the safety, tolerability, and effectiveness of VNS as a treatment
      option for adults with refractory FMS.

      Participants will be in this study for about 25 months. An initial screening period that may
      last up to 6 weeks will include a medical history review, various examinations, and the use
      of a wrist-mounted device called an Actiwatch to record pain severity and mood over seven
      consecutive days. Eligible participants will then undergo surgical implantation of the VNS
      system. This will be followed by a 2-week recovery period, then a 2-week period of gradually
      increasing the electrical output of the VNS system, and finally a 12-week VNS treatment
      period during which the electrical output level will remain constant, unless a participant
      develops intolerable side effects. Study visits will occur weekly for the first month after
      implantation and then every 2 weeks during the treatment period. During most study visits,
      participants will undergo a clinical assessment, including evaluation of any side effects,
      and they will complete written assessments on pain, mood, fatigue, and quality of life and
      sleep. The VNS system will also be checked for safety and programmed appropriately. During
      the Week 16 visit, some of the screening evaluations will be repeated. Also at Week 16, which
      will mark the end of the treatment period, participants will have the option to continue
      receiving treatment. All participants will have follow-up evaluations at Months 6, 9, 12, and
      24. Participants who wish to retain the VNS implantation beyond the length of the study will
      be referred to a qualified neurologist for follow-up care. For the other participants, the
      VNS system will be turned off and surgically explanted.
    

Intervention name(s): Vagus Nerve Stimulation (VNS) Therapy
Intervention type(s): Device
Intervention description(s): The VNS Therapy System Pulse Generator is an implantable, multi-programmable bipolar pulse generator. The pulse generator will deliver electrical signals to the vagus nerve via bipolar leads. A programming wand and software system enable non-invasive programming, functional assessments, interrogation, and data retrieval.
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Pain; Tenderness; Depression; Work Disability; Physical Function; Quality of Life; Chronic Pain