Bio-Surgery: Medicinal Leech Therapy and Medical Maggots — CPB 0556 | AETNA Coverage Update

Aetna modified CPB 0556 covering medicinal leech therapy and medical maggots, effective December 4, 2025. Here's what billing teams need to know before submitting claims.

Aetna, a CVS Health company, updated CPB 0556 — its bio-surgery coverage policy — to clarify medical necessity criteria for two therapies: medicinal leech (Hirudo medicinalis) therapy and medical maggot debridement. The primary billable code under this policy is CPT 97602 (non-selective debridement without anesthesia). If your team handles wound care, reconstructive surgery, or vascular surgery billing, this policy update draws a hard line between covered and non-covered indications you need to understand now.

Quick-Reference Table

Aetna Bio-Surgery Coverage Criteria and Medical Necessity Requirements 2025

The CPB 0556 Aetna coverage policy splits into two separate therapy types. The medical necessity rules are different for each. Don't treat them as interchangeable.

Medicinal Leech Therapy is covered for three specific indications. Poor venous drainage — meaning venous congestion or venous outflow obstruction — qualifies. Salvage of vascularly compromised flaps also qualifies. So does salvage of vascularly compromised replants after traumatic amputation. That's it. Three indications, and they all involve circulatory compromise in surgical or traumatic contexts.

Notice what's not on that list: inadequate arterial supply and tissue ischemia. Aetna explicitly calls those experimental. If your team sees leeches ordered for arterial insufficiency, that claim will deny. The policy is specific — venous compromise is covered, arterial is not.

Medical Maggot Therapy (and its equally covered alternative, bagged larval therapy) is medically necessary for debridement of five wound types: chronic diabetic foot ulcers, neuropathic foot ulcers, non-healing traumatic or post-surgical wounds, pressure ulcers, and venous stasis ulcers. These map to ICD-10 codes included in the policy's full 390-code list. Confirm the specific codes for diabetic foot complications, pressure ulcers, and venous stasis ulcers by pulling the complete list from the source policy at app.payerpolicy.org/p/aetna/0556.

When your team bills CPT 97602 for maggot debridement, the diagnosis code attached to that claim carries all the weight. A diabetic foot ulcer with the right ICD-10 code gets paid. A burn wound or a hand injury complicated by mycotic infection gets denied — Aetna calls both experimental under this policy.

Prior authorization requirements are not explicitly detailed in the CPB 0556 policy language, but given that leech therapy and maggot debridement are niche procedures with tight coverage criteria, confirm your specific plan's prior auth requirements before scheduling. Commercial plan riders and self-funded plan carve-outs can override the base policy. If you're billing across multiple Aetna plan types, talk to your compliance officer about which plans follow CPB 0556 directly.

Aetna Medicinal Leech and Medical Maggot Exclusions and Non-Covered Indications

The exclusion list for medicinal leech therapy is long — 13 named conditions — and some of them will surprise you.

Knee osteoarthritis and thumb osteoarthritis are both excluded. Leech therapy has a presence in some integrative medicine circles for joint pain, but Aetna considers it experimental for both. If your practice has seen rheumatology or orthopedic teams ordering leeches for joint conditions, those claims are not going through on this policy.

The same applies to complex regional pain syndrome (CRPS-I and CRPS-II), epicondylitis, low back pain, and cancer pain. These are all experimental under CPB 0556. The real issue here is that leech therapy has a broad traditional-medicine footprint, and Aetna is narrowing reimbursement strictly to surgical rescue scenarios.

Also worth flagging: leech therapy after rhinoplasty (CPT 30400–30462 range) is explicitly non-covered. The policy lists all rhinoplasty codes as "other CPT codes related to the CPB" — meaning they appear in the policy context but are not covered procedures for this therapy. If a reconstructive surgeon orders leeches post-rhinoplasty, expect a claim denial.

For maggot therapy, the exclusions are narrower but clear. Burn wounds and hand injuries complicated by mycotic infection are both experimental. The evidence base simply isn't there to support coverage in those cases, according to Aetna.

Coverage Indications at a Glance

Aetna Bio-Surgery Billing Guidelines and Action Items 2025

These steps apply to any team submitting claims under CPB 0556 after the December 4, 2025 effective date.

CPT, HCPCS, and ICD-10 Codes for Bio-Surgery Under CPB 0556

Covered CPT Codes (When Selection Criteria Are Met)

Other CPT Codes Related to CPB 0556 (Not Covered for Bio-Surgery)

These rhinoplasty codes appear in the CPB because post-rhinoplasty leech use is explicitly excluded. Billing leech therapy in conjunction with any of these procedure codes will not establish medical necessity under CPB 0556.

Key ICD-10-CM Diagnosis Codes

The full policy references 390 ICD-10-CM codes. Pull the complete list from the source policy at app.payerpolicy.org/p/aetna/0556 before building your charge capture crosswalk.