Open decompression and neurolysis of the ulnar nerve at the wrist (Guyon's canal), relieving compression through incision of constricting scar tissue or anatomical structures.

Verified May 8, 2026 · 5 sources ↓

Medicare: $387.78
Work RVU: 4.85
Global, days: 90
Region: Wrist

Drawn from CMSAAPCKzanowCgsmedicare

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 5 cited references ↓

Preoperative diagnostic studies (nerve conduction studies, EMG, or imaging) confirming ulnar nerve pathology at the wrist — required when billing 64719 alongside 64721
Operative note must name Guyon's canal as the surgical site, not generic 'wrist nerve decompression'
Description of structures released (palmar carpal ligament, fibrous bands, scar tissue) and confirmation of nerve decompression
Indication for surgery paragraph must reference preoperative diagnosis of ulnar nerve compression at the wrist, not just carpal tunnel syndrome
Laterality documented (left, right, or bilateral) to support LT/RT or modifier 50 appended to the claim
Intraoperative findings describing the degree of compression, nerve appearance, and any adhesions or masses encountered

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 24 Unrelated E/M during global 25 Significant separate E/M 51 Multiple procedures 57 Decision for surgery 58 Staged or related 59 Distinct service 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon LT Left side RT Right side 50 Bilateral procedure

What this code covers

Source · Editorial summary grounded in 5 cited references ↓

CPT 64719 covers open neuroplasty of the ulnar nerve at the wrist — specifically decompression at Guyon's canal, where the ulnar nerve and artery pass through a fibro-osseous tunnel formed by the pisiform, hook of hamate, and overlying palmar carpal ligament. The surgeon incises compressive scar tissue, fibrous bands, or other structural constraints to restore normal nerve excursion and reduce intraneural pressure. This is a distinct anatomic site from ulnar nerve surgery at the elbow (64718) and from median nerve carpal tunnel release (64721).

The 90-day global period covers the operative day, the day-before visit, and all routine postoperative care through day 90. New or unrelated problems in that window need modifier 24 (E/M) or 25 (same-day E/M). If a complication requires a return to the OR for a related procedure, use modifier 78; for an unrelated return procedure, use modifier 79. When 64719 is performed on the same hand as 64721, an NCCI bundling edit applies — modifier 59 unlocks the edit only when preoperative diagnostic studies documenting ulnar nerve pathology are present and explicitly referenced in the operative note's indication paragraph.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU vs. total RVU

The work RVU (4.85) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (11.61) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	4.85
Practice expense RVU	5.8
Malpractice RVU	0.96
Total RVU	11.61
Medicare national rate	$387.78
Global period	90 days

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Setting	Medicare rate (national)
Office (PFS non-facility) Procedure performed in physician's office	$387.78
HOPD (APC 5431) Hospital outpatient department	$1,995.02
ASC (PI A2) Ambulatory surgical center (freestanding)	$948.66

Common denial reasons

The recurring reasons claims for CPT 64719 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Bundling denial when billed same-day with 64721 without modifier 59 and supporting diagnostic study documentation
Lack of preoperative nerve conduction or EMG studies confirming ulnar neuropathy at Guyon's canal — payers treat this as insufficient medical necessity
Operative note defaults to 'carpal tunnel release' language without specifically identifying the ulnar nerve or Guyon's canal, causing code mismatch on audit
Missing laterality modifier when payer requires LT or RT for unilateral wrist procedures
Global period conflict — postoperative E/M billed without modifier 24 when the visit falls within the 90-day global window

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01Can I bill 64719 and 64721 together on the same hand?

Yes, but an NCCI bundling edit applies. To override it with modifier 59, you need documented preoperative diagnostic studies — nerve conduction studies or EMG — confirming ulnar nerve pathology at the wrist. That documentation must appear in both the preoperative diagnosis and the indication paragraph of the operative note. Without it, 64719 will be denied.

02What's the difference between 64718 and 64719?

64718 is ulnar nerve neuroplasty or transposition at the elbow (cubital tunnel). 64719 is ulnar nerve decompression at the wrist (Guyon's canal). Different anatomic sites, different RVU values, and no bundling conflict between them — bill both with modifier 51 on the lesser-valued code when performed in the same operative session.

03What modifier do I use if I return to the OR within the 90-day global for a related complication?

Modifier 78 covers an unplanned return to the OR for a procedure related to the original surgery during the global period. If the return procedure is unrelated to the original nerve decompression, use modifier 79 instead. Do not invert these — 78 is related, 79 is unrelated.

04Is modifier 50 appropriate for bilateral Guyon's canal decompression?

Yes. 64719 is inherently unilateral. If both wrists are decompressed in the same session, append modifier 50. Some payers prefer two line items with LT and RT; verify with the individual payer before submitting.

05What ICD-10 diagnoses support medical necessity for 64719?

Ulnar nerve entrapment at the wrist (G56.20–G56.22 for ulnar nerve lesions) is the primary diagnosis. Guyon's canal syndrome maps to this range. Ensure the laterality suffix matches the operative side. Payers will cross-reference the ICD-10 code against the CPT, so a carpal tunnel ICD-10 code (G56.00) paired with 64719 will trigger a mismatch denial.

06Does the 90-day global period affect billing for hand therapy referrals after surgery?

Hand therapy billed by the surgeon's own practice within the global period is included in the global and not separately reimbursable. Therapy billed by an independent therapist or separate entity is not affected by the surgeon's global period and bills normally.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira Scribe

Mira's AI scribe captures the anatomic site (Guyon's canal), structures released, intraoperative nerve findings, and any reference to concurrent median nerve pathology from dictation. It also flags when 64721 appears in the same encounter and prompts the surgeon to confirm preoperative diagnostic study references are included in the indication paragraph — the single most common reason payers deny 64719 when billed alongside carpal tunnel release.

See how Mira captures CPT 64719 documentation