Post-Market Feasibility Study of the Tenon Medical CATAMARAN™ SI Joint Fusion System

Inclusion Criteria: * Diagnosis of sacroiliac joint disruption or degenerative sacroiliitis based on ALL of the following: * Patient has pain at or close to the posterior superior iliac spine (PSIS) with possible radiation into buttocks, posterior thigh or groin and can point with a single finger to the location of pain (Fortin Finger Test), and * Patient has at least 3 of 5 physical examination maneuvers specific for SI joint pain (Fabers, Compression, Distraction,Thigh thrust, Gaenslen's test, and/or Sacral thrust test), and * Patient has improvement in lower back pain VAS of at least 50% of the pre injection VAS after fluoroscopic controlled injection of local anesthetic into affected SI joint(s) (including previous documented test \<6 months ago) * Patient has failed conservative care (non-surgical) \> 6 months * Patient has a pre-operative Oswestry Disability Index score \> 30% * Patient has a pre-operative SI joint pain score of \> 50 on a 0-100 mm visual analog scale (VAS) * Patient, or authorized representative, signs a written Informed Consent form to participate in the study * Patient is willing and able to complete study follow-up requirements Exclusion Criteria: * Planned bi-lateral SI joint fixation * Severe lower back pain due to other causes, such as lumbar disc degeneration, lumbar disc herniation, lumbar spondylolisthesis, lumbar spinal stenosis, lumbar facet degeneration, and lumbar vertebral body fracture (this is done by physical exam, medical hi…