Documentation · 7 min read · Nov 7, 2026
How to document conservative therapy so a lumbar MRI gets approved
Lumbar MRI requests are denied for the same few documentation gaps. A checklist for what to write, with a before-and-after example.
Lumbar spine MRI (CPT 72148 without contrast) is one of the most commonly denied outpatient imaging requests. Usually the patient needs the scan. The note just doesn't prove it in the terms the payer's policy uses.
What most policies look for
Payer policies vary, but most follow the same logic as the American College of Radiology's Appropriateness Criteria for low back pain. Imaging usually isn't indicated for uncomplicated low back pain in the first six weeks. It becomes appropriate when symptoms persist or progress after a course of conservative management in a patient who might need surgery or an intervention, or sooner when red flags are present.
Always check the specific payer and plan. Policies differ on required duration, accepted therapies, and how red flags must be documented.
The checklist
- Conservative therapy: type, dates, and response. "Has tried conservative treatment" usually fails. Write what was tried, when, for how long, and what happened: "Completed 8 weeks of physical therapy (Mar 2 – Apr 27) and daily naproxen 500 mg BID without improvement."
- Objective neurologic findings. Symptoms alone are weak evidence. Record the exam: straight-leg raise with the angle, reflexes, motor strength by myotome, and sensory changes by dermatome.
- Red flags, present or explicitly absent. Cauda equina symptoms, progressive neurologic deficit, history of cancer, fever or other signs of infection, and significant trauma or osteoporosis risk. If any are present, say so plainly. That may justify earlier imaging.
- How imaging changes management. Reviewers want to know the scan matters: "MRI to evaluate L5–S1 for surgical candidacy" or "to plan an epidural steroid injection."
- Specific, valid codes. M54.5 was deleted on October 1, 2021, and replaced by M54.50, M54.51, and M54.59. For radiculopathy, use a specific code such as M54.16 (lumbar region) or M51.16 when disc disorder with radiculopathy is documented.
Before and after
Before: "Low back pain × 3 months. Has tried conservative treatment. Pain radiates down the left leg. Lumbar radiculopathy, M54.5. Order MRI."
After: "Low back pain × 3 months radiating to the left leg. Completed 8 weeks of PT (Mar 2 – Apr 27) and daily naproxen without improvement. Exam: positive straight-leg raise on the left at 40°, diminished left ankle reflex, strength 5/5. No bowel or bladder changes, no history of cancer, afebrile. Lumbar radiculopathy (M54.16). MRI lumbar spine without contrast to evaluate for surgical candidacy."
The second version answers every question a reviewer will ask, in the order they'll ask it.
General information, not medical or billing advice. Confirm requirements against the specific payer's current policy. Reference: ACR Appropriateness Criteria.