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1. Determine the rate and incidence of peri-operative & post-operative adverse events (complications, infections, re-operations, re-admissions) in the endoscopic approach for the treatment of SIJ arthropathy and chronic lower back pain (CLBP).
2. Determine the Health-Related Quality of Life (HRQoL) using EQ-5D scale, VAS (Visual Analog Scale) & ODI (Oswestry Disability Index), outcomes following the endoscopic approach for the treatment of SIJ arthropathy and chronic lower back pain (CLBP) (pre- to post-operative changes).

Chronic low back pain (CLBP) that lasts for more than six months is estimated to occur in 60-80% of the general population in their lifetime and is associated with substantial healthcare costs. The sacroiliac joint (SIJ) complex is one of the major sources of CLBP, accounting for around 10-33% of the total number of CLBP cases. The SIJ complex consists of the joint capsule, synovia, various muscles and ligamentous structures overlying the join and neuronal structures that innervate the SIJ. Current interventional and surgical treatment options for SIJ complex mediated CLBP include intraarticular and periarticular injection of the joint, SIJ fusion and radio frequency ablation (RFA) of the neuronal structures innervating the SIJ. The described interventional procedures are simple procedures and provides quick pain relief, but the effect is short-lived. In addition, SIJ fusion is an invasive surgical procedure that should be reserved for refractory intractable pain of the SIJ1.

New endoscopic electrothermic ablation of the SIJ capsula, synovial and neuronal structures have been utilized in the treatment of facetogenic CLBP in a few number of clinical reports with favorable results, but to our knowledge, the efficacy of this technique when applied to SIJ-associated CLBP has not been reported. In this study, the investigators will utilize endoscopy for the precise microsurgical and ablation (ESIJ) of the potential pain generators associated with the SIJ and evaluate the clinical efficacy of this new technique.

Inclusion Criteria:

Subject age 18 - 85 years;

• SIJ arthropathy and chronic lower back pain (CLBP);
• Patient to undergo endoscopic electrothermic ablation of spinal levels S1-S3. The L4-L5 and/or L5-S1 facet joint can be included in the ablation per doctor discretion.
• Correct spinal levels (ranging L4-S3) to be treated have been confirmed by 1) diagnostic SIJ injection, followed by 2) diagnostic Medial/Lateral Branch Block at the applicable levels.
• The subject is likely to follow standard of care post-operative follow-up for at least 24 months.

Exclusion Criteria:

Patients receiving additional invasive back surgery after the study treatment.

• Inability to complete follow-up visits or required questionnaires.
• Non-compliant patients
• Difficult or impossible communication with the patient
• Breastfeeding, pregnant or patients who plan a pregnancy while participating in the study
• Systemic neurological disorders with mobility limitations (e.g. advanced Parkinson's disease or multiple sclerosis)
• Patients with incompatibilities or known limitations that make participation impossible
• Patients after stabilization with implants on thoracic or lumbar spine.
• Inability to provide informed consent without a legally authorized representative.