The study looks at a procedure called MILD (Minimally Invasive Lumbar Decompression), which helps relieve pressure in the lower back. It will compare this with another back procedure called IPD (Interspinous Process Decompression). The study will check how often these procedures are done again and any problems that might happen after 24 months. This study is special because it uses data from Medicare, a health insurance program, and doesn’t need patient consent. Patients must have Medicare and a specific back problem called LSS (Lumbar Spinal Stenosis) with NC. They can't join if they've had certain back surgeries in the past year.

• Study lasts for 24 months, using Medicare data.
• No extra visits or treatments are required from participants.
• Participants don't need to sign up or give consent.