Is unlisted procedure code 64999 medically necessary for a patient with sacrococcygeal disorders and chronic back pain?

Medical Necessity Determination for CPT Code 64999 in Sacrococcygeal Disorders

Based on current evidence, CPT code 64999 (unlisted nerve destruction procedure) is NOT medically necessary at this time for this patient with sacrococcygeal disorders and chronic back pain, as she has not completed an adequate trial of conservative management and has not met criteria for interventional procedures.

Clinical Context Analysis

This patient presents with:

• Post-traumatic sacrococcygeal pain (fall in kitchen, landing on back)
• Pain duration since the fall date with radiation to buttocks
• Partial response to gabapentin (7/10 to 5/10 pain reduction)
• Only 2 sessions of physical therapy completed
• Current pain level 6/10
• MRI L-spine findings positive for tenderness with flexion/extension

Evidence-Based Treatment Algorithm

Step 1: Conservative Management (REQUIRED FIRST)

The 2025 BMJ clinical practice guideline provides a strong recommendation AGAINST interventional procedures for chronic axial spine pain, including epidural injections, joint radiofrequency ablation, joint-targeted injections, and intramuscular injections 1. This represents the highest quality and most recent guideline evidence available.

Critical deficiency in this case: The patient has completed only 2 physical therapy sessions, which is grossly inadequate. Conservative therapy for coccydynia should include 2, 3:

• Extended physical therapy (minimum 6-12 weeks, not 2 sessions)
• Manual therapy including massage and stretching of levator ani muscle
• Mobilization of the coccyx
• Coccyx cushion for sitting
• Optimization of medication management
• Acupuncture consideration

Step 2: Diagnostic Confirmation (NOT YET COMPLETED)

Before any interventional procedure can be considered medically necessary, the diagnosis must be confirmed through 2, 3:

• Dynamic radiographs (lateral X-rays in standing AND sitting positions) to assess coccygeal mobility - abnormal mobility is present in 70% of coccydynia cases
• Diagnostic injection of local anesthetic into sacrococcygeal disc, first intercoccygeal disc, or Walther's ganglion to confirm coccygeal origin of pain
• Exclusion of extracoccygeal causes (pilonidal cyst, perianal abscess, hemorrhoids, pelvic organ disease, lumbosacral spine disorders, sacroiliac joint dysfunction)

The patient's MRI shows positive findings in the lumbar spine, but there is no documentation of dynamic coccyx imaging or diagnostic blocks to confirm sacrococcygeal origin.

Step 3: Interventional Procedures (Only After Conservative Failure)

If conservative management fails after adequate trial (typically 3-6 months), the evidence supports 2, 4, 3, 5:

First-line interventional options:

• Intra-articular sacroiliac joint infiltrations with local anesthetic and corticosteroids (evidence rating 1 B+) 2
• Injections of local anesthetic and corticosteroid into painful sacrococcygeal structures 3

Second-line interventional options (if first-line fails):

• Cooled radiofrequency treatment of lateral branches S1-S3 (evidence rating 2 B+) 2
• Pulsed radiofrequency of L5 dorsal ramus and lateral branches S1-S3 (evidence rating 2 C+) 2
• Novel pericapsular radiofrequency ablation of sacrococcygeal junction 4
• Cryoablation of sacrococcygeal nerves under combined ultrasound-fluoroscopy guidance 5

Surgical option (last resort):

• Partial or total coccygectomy - reserved for refractory cases with confirmed abnormal coccygeal mobility and spicules 3

Specific Criteria NOT Met

1. Inadequate conservative management: Only 2 PT sessions vs. required 6-12 weeks minimum
2. No diagnostic confirmation: No dynamic radiographs, no diagnostic blocks performed
3. Incomplete medication optimization: Patient responding to gabapentin but no documentation of dose optimization or multimodal analgesia trial
4. No documentation of sacroiliac joint evaluation: Given the strong evidence for SI joint as source of 16-30% of chronic mechanical low back pain 2
5. Contradicts highest quality guideline: The 2025 BMJ guideline provides strong recommendation AGAINST interventional procedures for chronic axial spine pain 1

Common Pitfalls to Avoid

• Premature intervention: Rushing to procedures before adequate conservative trial is the most common error in coccydynia management 3
• Failure to obtain dynamic imaging: Static radiographs miss 70% of pathology (abnormal mobility) 3
• Skipping diagnostic blocks: Without confirmation of pain source, interventions have high failure rates 2
• Ignoring alternative diagnoses: 30% of coccydynia is idiopathic, and extracoccygeal sources must be excluded 3

Recommendation

DENY authorization for CPT 64999 at this time. The patient requires:

1. Completion of structured physical therapy program (minimum 6-12 weeks) with manual therapy and coccyx mobilization
2. Dynamic radiographs (standing and sitting lateral views) of coccyx
3. Optimization of medical management
4. If symptoms persist after adequate conservative trial, diagnostic injection to confirm pain source
5. Only after documented failure of above steps should interventional procedures be reconsidered

The 2025 BMJ guideline's strong recommendation against interventional procedures for chronic axial spine pain, combined with inadequate conservative management in this case, makes the requested procedure medically unnecessary at this time 1.