Inclusion Criteria:
1. Age range (18-80 years): The age range of the patient population at Hershey Medical Center with facet pain is 24 to 90 years old, with a mean age of 63 years old. Due to the physical tests planned in the study, the maximum age limit will be restricted to 80 years old.
2. English Speaking: Adults who only speak other languages will not be included because of the lack of feasibility of employing reliable instruments and interviewers fluent in other languages.
3. Facet Joint Pain: male and female patients having a diagnosis of facet joint pain based upon accepted diagnostic criteria (i.e., two positive nerve blocks) and assessed by an experienced physical therapist or physician.
4. Indication for Surgical Procedure: Physical therapy is the first line of action for facet joint pain. If PT is not effective, patients are eligible for RFA or PNS.
Exclusion Criteria:
1. Previous Spinal Conditions Surgery: We will exclude patients with other spinal conditions like scoliosis or who have received previous spinal surgeries.
2. Systemic neurological or neuromuscular disease: Such disorders (e.g., stroke, muscular dystrophy, myopathies) affect muscle and may confound muscle data and/or balance and physical performance data.
3. Allergic reaction to ultrasound gels: It is possible, although rare, that patients develop allergic reaction to ultrasound gels. Those subjects will be excluded from the study.
4. Physical Activity: Subjects will be asked to fill out the Physical Activity Readiness Questionnaire (PAR-Q), and if they answer yes to any of the questions, they need to be cleared by their physician prior to participating in the study.
5. Current infection, illness, or condition: Individuals with a current infection, illness, or condition (e.g., uncontrolled blood pressure, pregnancy) that may affect their ability to safely participate will be excluded.
6. Mental incompetency: Individuals who cannot legally consent themselves to the surgical procedure and participation in the research study, will not be considered for inclusion.
7. Patients who have a Deep Brain Stimulation (DBS) system.
8. Patients who have an implanted active cardiac implant (e.g. pacemaker or defibrillator).
9. Patients who have any other implantable neuro-stimulator whose stimulus current pathway may overlap with that of the SPRINT System.
