CPT Codes 64400–64448: The Complete Nerve Block Billing Guide

Key Takeaways

• CPT codes 64400–64448 sit inside the broader 64400–64489 “Introduction/Injection of Anesthetic Agent (Nerve Block)” section of the CPT manual, covering diagnostic and therapeutic somatic nerve injections from the head down through the lower extremity.
• Each code in this range is anatomy-specific — 64400 is trigeminal, 64447 is femoral, 64445 is sciatic — and billing the wrong code for the nerve actually injected is the single most common cause of denials in this series.
• Continuous infusion nerve blocks (placed via catheter for extended pain control) use dedicated add-on codes — +64416, +64446, +64448 — that can only be billed alongside their corresponding base code.
• Modifiers -50 (bilateral), -59 (distinct procedural service), -LT/-RT, and -25 (same-day E/M) govern most of the disputes payers raise on claims in this range.
• Medical necessity documentation — the nerve targeted, agent and dose, imaging guidance used, and a linked ICD-10-CM diagnosis — needs to be airtight before the claim goes out, since payer LCDs vary by jurisdiction.

Nerve block injections are billed constantly across pain management, anesthesiology, orthopedics, and neurology, yet the CPT codes covering them are frequently mixed up. CPT 64400–64448 spans everything from a trigeminal nerve block for facial neuralgia to a femoral nerve block placed before knee surgery — and no two codes in the range share a reimbursement rate, a modifier rule, or an ICD-10 pairing.

This guide walks through every code from 64400 to 64448, in anatomical order, with the descriptor, common clinical use, applicable modifiers, and the billing pitfalls that trigger denials. Always confirm current rates and coverage criteria against the CMS Physician Fee Schedule and your Medicare Administrative Contractor’s (MAC) Local Coverage Determination (LCD), since both are updated periodically and figures below are national averages.

Table of Contents

1. What the 64400–64489 CPT series covers
2. CPT code 64400–64448 quick-reference table
3. Cranial and head nerve blocks (64400–64413)
4. Upper extremity nerve blocks (64415–64418)
5. Trunk and pelvic nerve blocks (64420–64435)
6. Lower extremity nerve blocks (64445–64448)
7. Modifiers for CPT 64400–64448
8. ICD-10-CM pairings by body region
9. Documentation requirements
10. Billing with E/M services and anesthesia
11. NCCI edits and bundling rules
12. Common coding errors in this range
13. Frequently asked questions

What the 64400–64489 CPT series covers

The American Medical Association (AMA), which maintains the CPT code set, groups CPT 64400–64489 under “Introduction/Injection of Anesthetic Agent (Nerve Block), Diagnostic or Therapeutic” — somatic (as opposed to sympathetic) nerve blocks. Sympathetic chain procedures, like stellate ganglion or celiac plexus blocks, sit in a separate range (64505–64530) with their own rules and aren’t covered here.

Within 64400–64489, codes are organized by the nerve or nerve group injected, moving roughly head-to-toe. CPT 64400–64448 covers the cranial, upper extremity, trunk, pelvic, and lower extremity segment of that range. Each base code represents a single injection (or set of injections into that same nerve at one encounter); several have a matching add-on code for continuous infusion via an indwelling catheter, used when pain control needs to extend beyond a single injection’s duration.

Three things determine which code applies:

• The specific nerve targeted. Codes are not interchangeable between nerves — a femoral block is 64447, not 64450 (the “other peripheral nerve” catch-all code used only when no anatomy-specific code exists).
• Single injection vs. continuous infusion. A one-time injection uses the base code; placing a catheter for ongoing infusion adds the corresponding add-on code.
• Bilateral or multiple distinct sites. These require modifiers rather than a different code.

CPT code 64400–64448 quick-reference table

Codes marked with a “+” are add-on codes and are never billed as a standalone line — they must accompany their base code on the same claim.

Cranial and head nerve blocks (64400–64413)

CPT 64400 — Trigeminal nerve block

The trigeminal nerve (cranial nerve V) splits into three divisions — V1 (ophthalmic), V2 (maxillary), and V3 (mandibular) — and CPT 64400 covers an injection into any one of them. A single unit is billed per encounter regardless of which branch is targeted, unless multiple distinct branches are injected in the same session, in which case a second unit with modifier -59 may be supportable with clear documentation.

Common indications: trigeminal neuralgia (G50.0), atypical facial pain (G50.1), and postherpetic trigeminal neuralgia (B02.22). Non-facility Medicare reimbursement typically runs higher than facility-based rates because practice expense RVUs differ by place of service — always confirm current figures against the CMS PFS lookup tool.

CPT 64402 — Facial nerve block

Used less frequently than 64400, this code covers injection into the facial nerve (cranial nerve VII), most often for diagnostic purposes in conditions like hemifacial spasm or Bell’s palsy evaluation, rather than as a primary pain-management tool.

CPT 64405 — Greater occipital nerve block

One of the highest-volume codes in this range for headache and migraine practices. CPT 64405 covers injection into the greater (or lesser) occipital nerve for occipital neuralgia and chronic migraine prophylaxis. Bilateral injections are common — this is one of the codes most frequently billed with modifier -50, since occipital neuralgia often presents bilaterally.

CPT 64408 — Vagus nerve block

A less commonly billed code, used for select chronic pain and autonomic nerve procedures targeting the vagus nerve. Documentation should clearly establish medical necessity, as coverage varies significantly by payer.

CPT 64410 — Phrenic nerve block

Typically diagnostic — used to evaluate intractable hiccups or diaphragmatic dysfunction by temporarily blocking phrenic nerve conduction. Rarely billed in high volume outside specialized pulmonology or pain practices.

CPT 64413 — Cervical plexus block

Covers injection into the cervical plexus, often used as an anesthetic adjunct for neck surgeries (such as carotid endarterectomy) or for cervical pain syndromes. Distinguish this from cervical epidural or facet injections, which fall under entirely different CPT codes outside this series.

Upper extremity nerve blocks (64415–64418)

CPT 64415 — Brachial plexus block (single injection)

Covers a single injection into the brachial plexus, most often used for shoulder, arm, or hand surgical anesthesia and post-operative analgesia. Approaches include interscalene, supraclavicular, and infraclavicular, each carrying different risk profiles (interscalene carries a documented risk of phrenic nerve involvement and transient diaphragmatic weakness).

+64416 — Brachial plexus, continuous infusion

An add-on code reported alongside 64415 when a catheter is placed for continuous infusion rather than a single bolus injection. This extends analgesia over multiple days, common after major shoulder reconstruction. It cannot be billed without the corresponding base procedure on the same claim.

CPT 64417 — Axillary nerve block

Targets the axillary nerve specifically, generally for shoulder-region procedures where a more limited block than a full brachial plexus injection is clinically appropriate.

CPT 64418 — Suprascapular nerve block

Frequently used for shoulder pain management, including adhesive capsulitis (“frozen shoulder”) and chronic rotator cuff-related pain, often performed in an office setting under ultrasound guidance.

Trunk and pelvic nerve blocks (64420–64435)

CPT 64420 vs. 64421 — Intercostal nerve blocks

This pairing causes recurring billing errors. CPT 64420 covers a single intercostal nerve level; CPT 64421 covers multiple levels in the same session. Billing several units of 64420 instead of a single unit of 64421 when multiple rib levels are injected is a well-documented coding error that leads to denials or requires post-payment correction. Common indications include rib fracture pain and post-thoracotomy pain management.

CPT 64425 — Ilioinguinal/iliohypogastric nerve block

Targets the ilioinguinal and iliohypogastric nerves together, commonly used for groin pain following hernia repair or for chronic inguinal neuralgia.

CPT 64430 — Pudendal nerve block

Used in both obstetric settings (for labor and delivery analgesia) and chronic pelvic pain management. Approach and laterality should be clearly documented, since pudendal blocks are frequently performed bilaterally.

CPT 64435 — Paracervical (uterine) nerve block

An obstetric and gynecologic procedure code, covering injection around the paracervical region for uterine-related pain control, most often during certain labor or gynecologic procedures.

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Lower extremity nerve blocks (64445–64448)

CPT 64445 — Sciatic nerve block (single injection)

Covers single-injection sciatic nerve blocks used for lower limb surgical anesthesia (foot, ankle, lower leg) and for managing sciatica-related pain. Popliteal blocks, performed at a more distal point along the sciatic nerve, are also reported under this code.

+64446 — Sciatic nerve, continuous infusion

Add-on code for catheter-based continuous sciatic nerve infusion, typically used after major foot, ankle, or lower-leg surgery for extended post-operative pain control. Must be billed with 64445 on the same claim.

CPT 64447 — Femoral nerve block (single injection)

One of the most frequently billed codes in this entire range, given its role in total knee arthroplasty, ACL reconstruction, and hip fracture pain management. Femoral nerve blocks reduce post-operative opioid requirements and are a standard component of multimodal analgesia protocols in orthopedic surgery.

+64448 — Femoral nerve, continuous infusion

Add-on code for catheter placement enabling continuous femoral nerve infusion, common after total knee replacement where multi-day analgesia meaningfully improves early mobilization outcomes. Like the other continuous-infusion add-ons, it is never billed without its base code.

Modifiers for CPT 64400–64448

Bilateral billing format is the single most payer-variable rule in this range. Confirm each payer’s preference before submitting — the wrong format (a single -50 line vs. two -LT/-RT lines) is a common cause of underpayment or outright denial.

ICD-10-CM pairings by body region

Medical necessity for any code in this range depends on an ICD-10-CM diagnosis that clinically supports the specific nerve injected. A mismatch between the nerve block code and the diagnosis code is a leading denial trigger.

Always verify current covered diagnoses against your MAC’s LCD — coverage criteria differ by jurisdiction and are updated periodically. The AAPC CPT-to-ICD-10 crosswalk is a useful secondary reference for identifying additional supported pairings.

Documentation requirements

Every claim in the 64400–64448 range should be supported by a procedure note that includes:

• Clinical indication — the specific diagnosis driving the block, matching the ICD-10-CM code billed.
• Nerve and side targeted — including which branch, if applicable (e.g., V2 for trigeminal), and laterality.
• Agent, dose, and volume — the anesthetic and/or steroid used.
• Guidance used — ultrasound, fluoroscopy, or landmark technique, and whether a separate guidance code was billed.
• Single injection vs. catheter placement — required to justify billing a base code alone versus a base code plus its continuous-infusion add-on.
• Informed consent documentation.
• Post-procedure response — particularly important for repeat procedures, where ongoing medical necessity needs to be demonstrated.

Many payers, including Medicare, expect evidence of failed conservative treatment (physical therapy, oral analgesics, prior injections) before approving nerve block coverage, especially for chronic pain indications. This is typically reviewed most closely on initial claims and repeat-procedure requests.

Billing with E/M services and anesthesia

Same-day E/M billing alongside a nerve block code is one of the most frequently audited scenarios in this range. The general rule: the E/M service must represent a significant, separately identifiable evaluation, distinct from the assessment inherently bundled into the nerve block procedure itself.

• Modifier -25 applies to the E/M code, never to the nerve block code, and only when the documentation shows a distinct decision-making event — for example, evaluating a new complaint or adjusting a broader pain management plan — apart from the pre-injection assessment.
• Routine pre-injection evaluation (confirming the injection site, reviewing the plan, obtaining consent) is part of the nerve block’s surgical package and is not separately billable.
• When a nerve block is performed for post-operative pain control rather than as the primary anesthetic for a surgery, it may be separately reportable from the anesthesia service under current NCCI guidance — confirm the specific pairing against the current NCCI edit tables, since rules here are updated periodically.

NCCI edits and bundling rules

The National Correct Coding Initiative (NCCI) maintains quarterly-updated edit pairs that determine which codes can and cannot be billed together without a modifier. For CPT 64400–64448:

• Imaging guidance codes (e.g., 76942 for ultrasound guidance, 77002/77003 for fluoroscopic guidance) may be separately reportable depending on the specific base code and payer policy — some codes in the broader 64400–64489 series bundle guidance, others don’t. Confirm the specific pairing before billing.
• The pre-injection evaluation required to determine injection site and approach is bundled into the surgical package of the base code and is not separately billable as an E/M service.
• Multiple distinct nerve injections at the same encounter (e.g., a femoral block and a separate sciatic block for the same surgery) may support billing both base codes together, generally with modifier -59 on the second code, provided documentation clearly shows each was a separate, medically distinct injection.
• Continuous-infusion add-on codes (+64416, +64446, +64448) will always be denied if billed without their corresponding base code on the same claim.

Always check the current NCCI Policy Manual and edit tables, published by CMS, before submitting claims that combine codes from this range with imaging or anesthesia services.

Common coding errors in this range

• Using 64450 (other peripheral nerve) when a specific code exists. If the nerve has a dedicated code in the 64400–64489 series — trigeminal, femoral, sciatic, and so on — that code must be used instead of the generic 64450 catch-all.
• Billing multiple units of a single-level code instead of the multi-level code. This is the classic 64420-vs-64421 intercostal error: multiple single-level units should instead be one unit of 64421.
• Billing the continuous-infusion add-on without the base code, or vice versa when a catheter was actually placed.
• Missing bilateral modifiers. Forgetting -50 (or -LT/-RT, depending on payer) when the procedure was performed on both sides.
• Appending -25 to the nerve block code instead of the E/M code, or using -25 to bill for the routine pre-injection assessment that’s already bundled into the procedure.
• Diagnosis-procedure mismatch — an ICD-10-CM code that doesn’t clinically support the specific nerve injected, a frequent trigger for medical necessity denials.

Frequently asked questions

What does the CPT 64400–64448 range cover?

It covers single-injection and continuous-infusion nerve blocks from the trigeminal nerve down through the femoral nerve — cranial, upper extremity, trunk, pelvic, and proximal lower extremity somatic nerve injections. It sits within the larger 64400–64489 series for somatic nerve block procedures.

What’s the difference between 64445 and 64447?

CPT 64445 covers a sciatic nerve block; CPT 64447 covers a femoral nerve block. They’re often performed together for knee and lower-limb surgery (a combined femoral-sciatic block), but they represent two distinct nerves and are billed as two separate codes, typically with modifier -59 on the second when documentation supports it.

When do I use the continuous-infusion add-on codes (+64416, +64446, +64448)?

Only when a catheter is placed to deliver ongoing anesthetic infusion beyond the initial injection, and only alongside the matching base code on the same claim. A single-shot injection with no catheter never justifies billing the add-on code.

How is a bilateral nerve block billed in this range?

Most commonly with modifier -50 appended to the base code, which Medicare typically reimburses at 150% of the unilateral rate. Some commercial payers instead require two separate line items using modifiers -LT and -RT. Confirm the required format with each payer before submitting.

Can these codes be billed alongside anesthesia for the same surgery?

Only when the nerve block is for post-operative pain management rather than serving as the primary surgical anesthetic. If the block is the anesthesia technique used for the surgery itself, it’s generally not separately billable from the anesthesia service.

What’s the most common reason claims in this range get denied?

Two issues dominate: using the wrong anatomy-specific code (or defaulting to 64450 when a specific code exists), and an ICD-10-CM diagnosis that doesn’t clearly support medical necessity for the specific nerve injected.

This guide is intended as a coding reference and does not replace verification against your Medicare Administrative Contractor’s current LCD, the CMS NCCI Policy Manual, or individual payer policies, all of which are updated periodically and take precedence over general guidance.