15758

🔬 CPT Code 15758 — Free Fascial Flap with Microvascular Anastomosis

Quick Reference

Global Period: 090 days | wRVU: 25.14 | Assistant Payable: ✅ Yes | Co-Surgeon: ✅ Yes | Category: Reconstructive – Integumentary | Tissue: Fascia only — NO skin paddle

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📋 Official CPT Description

CPT 15758 — Free fascial flap with microvascular anastomosis

This code describes the harvest and microsurgical free transfer of a fascial flap only — connective tissue fascia without an attached skin paddle — from a donor site to a geographically distant recipient site, requiring microvascular anastomosis to restore perfusion at the recipient location. The absence of a skin paddle is the defining clinical and coding feature that distinguishes 15758 from 15757 (which includes skin) and 15756 (which includes muscle).

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🧠 Detailed Clinical Description

What Is a Free Fascial Flap?

A free fascial flap is a highly specialized microsurgical transfer consisting primarily of fascia — the dense fibrous connective tissue layer that invests muscles, neurovascular bundles, and deep structures throughout the body. When harvested as a free fascial flap, the tissue is completely detached from its native blood supply and re-vascularized through microsurgical vessel repair at the recipient site.

Fascial flaps are uniquely valued for their:

• Extreme thinness and pliability — conforming to complex three-dimensional contours
• Rich vascular network within the fascial plane — supporting excellent perfusion
• Minimal donor site bulk — critical in areas where volume is undesirable (e.g., periorbital, auricular, nasal, and hand reconstruction)
• Capacity to be skin-grafted secondarily — the fascial surface accepts split-thickness skin grafts readily, enabling staged reconstruction
• Low donor site morbidity compared to myocutaneous or muscle free flaps

Tissue Components Covered Under 15758

Component	Included?
Epidermis / Dermis (skin paddle)	❌ No
Subcutaneous adipose tissue	❌ Minimal to none
Deep investing fascia	✅ Yes — primary tissue
Superficial fascial layer	✅ Yes (flap-dependent)
Named vascular pedicle within fascia	✅ Yes
Muscle bulk	❌ No

Free Flap Type Comparison — The Full Triad

Code	Tissue Transferred	Skin Paddle	Muscle	Fascia
15756	Muscle or myocutaneous	Optional	✅ Yes	Optional
15757	Skin / fasciocutaneous	✅ Yes	❌ No	✅ Often
15758	Fascial only	❌ No	❌ No	✅ Yes

The Defining Distinction

If the operative report describes harvest of skin with the flap — even a small skin paddle — the code is 15757, not 15758. 15758 is reserved for cases where fascia alone is transferred, typically with planned secondary split-thickness skin grafting over the fascial surface at the recipient site, or for buried fascial coverage applications (e.g., dural repair, orbital reconstruction).

Surgical Steps Included in 15758

1. Preoperative vascular mapping — Handheld Doppler or CT angiography to identify fascial perforators and plan pedicle harvest (bundled into global)
2. Donor site preparation and access — Incisions designed to harvest fascia without incorporating skin island
3. Fascial flap elevation — Careful dissection in the subfascial or intrafascial plane; preservation of the named fascial vascular pedicle
4. Pedicle ligation and complete flap detachment — Vessel division, flap removed from donor site
5. Recipient site preparation — Debridement, tumor bed or wound bed development, exposure of recipient vessels
6. Microvascular anastomosis — Arterial and venous coaptation under operative microscopy or high-power surgical loupes (end-to-end or end-to-side)
7. Fascial flap inset — Suture fixation of fascia into recipient defect; contouring and tailoring
8. Secondary skin grafting over fascial surface (when planned) — Split-thickness autograft placed over the revascularized fascial flap (reported separately — see Excludes)
9. Donor site closure — Primary closure of donor skin; skin graft of donor site if required (reported separately)
10. Postoperative monitoring — Included within global period

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💰 Reimbursement & RVU Profile

Component	Value
Work RVU (wRVU)	25.14 CMS MPFS 2025
Global Period	090 days
Assistant Surgeon Payable	✅ Yes (Indicator: 1)
Co-Surgeon Payable	✅ Yes
Team Surgery	✅ Yes
Facility Only	Yes (hospital/ASC setting)
Multiple Procedure Indicator	2 (standard reduction applies)
Bilateral Surgery Indicator	0 (not applicable)

wRVU Hierarchy Across the Free Flap Triad

Code	wRVU	Tissue
15756	35.38	Muscle/myocutaneous
15757	30.32	Skin/fasciocutaneous
15758	25.14	Fascial only

15758 carries the lowest wRVU of the three free flap codes, reflecting reduced tissue bulk, shorter harvest time, and typically lower donor site complexity. However, microsurgical skill and anastomotic requirements remain identical — it is not a “simpler” procedure in the operative sense.

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✅ Included Services (Bundled into 15758)

The following are not separately reportable when performed as integral components of 15758:

• Harvest and elevation of the fascial flap from the donor site
• Microvascular arterial and venous anastomosis (primary)
• Fascial flap inset and suture fixation into recipient defect
• Simple or intermediate closure of donor skin
• Intraoperative Doppler or perfusion assessment of flap viability
• Routine wound irrigation and debridement at recipient site
• Routine postoperative monitoring within the 90-day global period
• Routine dressing changes and suture/staple removal within global

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❌ Excludes / Separately Reportable Services

The following may be billed separately when clearly documented:

Separate Service	Code
Split-thickness skin graft placed over fascial flap surface	15100–15115
Complex donor site closure (meets criteria for complex repair)	13100–13160
Skin graft to donor site (when primary closure not achievable)	15100–15115
Nerve coaptation performed with the free flap	64905, 64907
Re-exploration / revision of microvascular anastomosis (separate OR session)	15758 with modifier 78
Vein graft interposition for pedicle extension	35500
Bone graft harvest for composite reconstruction (separate session)	20900–20902
Secondary debridement of unrelated wound	97597–97598
Staged flap division or secondary inset	15630

Skin Graft Billing — Most Common Addendum to 15758

Because 15758 transfers fascia without a skin paddle, the exposed fascial surface at the recipient site is frequently covered with a split-thickness skin graft (STSG) in the same operative session or a staged second procedure. The STSG is separately reportable (e.g., 15100 for trunk/arms/legs or 15115 for face/scalp). Append modifier 59 if performed at the same session as 15758 to clarify distinct service — and verify against current NCCI edits.

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🏥 Common Donor Flap Sources — Fascial Free Flaps

Donor Flap	Primary Tissue	Vascular Pedicle	Classic Recipient Application
Temporoparietal Fascial (TPF) Flap	Superficial temporal fascia	Superficial temporal artery/vein	Ear reconstruction (auricular framework coverage), orbital reconstruction, nasal lining, scalp, hand
Deep Temporal Fascial Flap	Deep temporal fascia	Middle temporal artery	Orbital reconstruction, eyelid, skull base
Serratus Fascia Free Flap	Serratus fascia (without muscle)	Long thoracic / lateral thoracic a/v	Extremity, hand tendon gliding surface
Thoracodorsal Artery Perforator (TDAP) Fascial	Thoracodorsal fascia only	Thoracodorsal a/v	Thin resurfacing, hand dorsum
Lateral Arm Fascial Flap	Lateral intermuscular septal fascia	Posterior radial collateral a/v	Hand, digit, face — ultra-thin coverage
Radial Forearm Fascial Flap	Deep forearm fascia	Radial artery / cephalic vein	Tendon gliding surface, periorbital, auricular, nasal

Temporoparietal Fascial (TPF) Free Flap — The Signature 15758 Case

The TPF flap is the most commonly cited clinical example for 15758. It consists of the superficial temporal fascia — an extremely thin (1–3 mm), highly vascular fascial layer located beneath the scalp’s subcutaneous fat and above the deep temporal fascia. Its named blood supply (superficial temporal artery and vein) makes it a reliable free flap. The TPF can be transferred to reconstruct:

• The auricle (covering a cartilaginous framework in microtia or trauma reconstruction)
• Orbital defects — lining the orbit after exenteration
• Nasal lining in complex nasal reconstruction
• The hand dorsum for tendon gliding surface restoration
• Scalp defects requiring thin, pliable coverage

After inset, the exposed fascial surface is skin-grafted (STSG) — coded separately as 15100 or 15115.

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🏷️ Applicable Modifiers

Modifier	Description	When to Use
-51	Multiple procedures	When 15758 is billed alongside another major procedure (e.g., auricular reconstruction, tumor resection)
-59	Distinct procedural service	To unbundle separately identifiable services at a distinct anatomical site (e.g., STSG at recipient over fascial flap)
-80	Assistant surgeon	Second surgeon assists; medically necessary given microsurgical complexity — payable
-82	Assistant surgeon (no resident available)	Teaching hospital alternative when no qualified resident is available
-AS	Assistant at surgery – NP/PA	Non-physician practitioner assisting at table
-22	Increased procedural complexity	Prior radiation, significant scarring, obesity, complex anatomy, exceptionally prolonged operative time; requires thorough operative documentation and cover letter
-52	Reduced services	Partial procedure; rarely applicable in microsurgery
-78	Return to OR for related procedure	Re-exploration for anastomotic failure, partial flap loss, hematoma during global period
-79	Unrelated procedure during global period	Separate, unrelated surgery within 90-day global
-LT / -RT	Left / Right laterality	When laterality of recipient site is clinically relevant

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🩺 ICD-10-CM Diagnoses Commonly Paired with 15758

Congenital Anomalies — Ear / Auricular Reconstruction

ICD-10-CM	Description	HCC?
Q16.0	Congenital absence of auricle (microtia)	❌
Q17.2	Microtia	❌
Q17.8	Other specified congenital malformations of ear	❌
Q18.9	Congenital malformation of face and neck, unspecified	❌

Microtia and the TPF Free Flap

Microtia reconstruction is one of the most common scenarios for 15758. After a cartilaginous auricular framework is carved (from rib cartilage, coded separately as 21230) and placed subcutaneously, a TPF free flap is elevated and wrapped around the framework to provide thin, vascular coverage. An STSG is then applied. The full procedure often spans multiple staged surgeries — each separately coded.

Malignant Neoplasms (Post-Resection Reconstruction)

ICD-10-CM	Description	HCC?
C30.0	Malignant neoplasm of nasal cavity	✅ HCC 11
C31.0	Malignant neoplasm of maxillary sinus	✅ HCC 11
C31.9	Malignant neoplasm of accessory sinus, unspecified	✅ HCC 11
C44.319	Squamous cell carcinoma of skin, unspecified part of face	✅ HCC 12
C44.41	Merkel cell carcinoma of scalp and neck	✅ HCC 12
C44.319	SCC of face, unspecified	✅ HCC 12
C69.60	Malignant neoplasm of unspecified orbit	✅ HCC 11
C69.61	Malignant neoplasm of right orbit	✅ HCC 11
C69.62	Malignant neoplasm of left orbit	✅ HCC 11
C41.0	Malignant neoplasm of bones of skull and face	✅ HCC 11
C49.0	Malignant neoplasm of connective and soft tissue, head/neck	✅ HCC 11
C71.9	Malignant neoplasm of brain, unspecified	✅ HCC 10

HCC Capture — Active Malignancy

If the fascial free flap is performed as part of an ongoing oncologic treatment episode, code the active malignancy (e.g., C69.61) — not the personal history code. Active malignancy diagnoses carry HCC weights (HCC 10–12 depending on site) and directly impact risk-adjustment scores under Medicare Advantage and value-based contracts. Confirm with the treating surgeon whether the diagnosis is still active vs. in remission before assigning Z85.xx.

Traumatic Wounds / Acquired Defects

ICD-10-CM	Description	HCC?
S09.90XA	Unspecified injury of head, initial encounter	❌
S00.01XA	Unspecified superficial injury of scalp, initial encounter	❌
S09.8XXA	Other specified injuries of head, initial encounter	❌
S41.001A	Unspecified open wound of right shoulder, initial	❌
S61.401A	Unspecified open wound of right hand, initial	❌
S61.402A	Unspecified open wound of left hand, initial	❌
S68.411A	Complete traumatic amputation of right index finger, initial	❌
T20.30XA	Burn of third degree of head, unspecified site, initial	❌
T23.301A	Burn of third degree of right hand, unspecified site, initial	❌

Orbital / Ophthalmic Pathology — Oculoplastics Context

ICD-10-CM	Description	HCC?
H05.011	Cellulitis of right orbit	❌
H05.012	Cellulitis of left orbit	❌
H05.811	Cyst of right orbit	❌
H05.812	Cyst of left orbit	❌
H05.821	Myopathy of extraocular muscles, right orbit	❌
Z90.01	Acquired absence of eye	❌
H05.401	Unspecified enophthalmos, right eye	❌

Ophthalmology / Oculoplastics Context

In orbital exenteration cases (e.g., after 65110 or 65112) where the orbit requires fascial lining or volume restoration, a free fascial flap (15758) is occasionally used — particularly when thin, well-vascularized tissue is preferred over bulkier myocutaneous options. The TPF flap or a radial forearm fascial flap may be chosen to line the orbital socket and subsequently skin-grafted. This is a niche but well-documented application in oculoplastic and skull base surgery.

Nasal / Sinus Reconstruction

ICD-10-CM	Description	HCC?
J34.89	Other specified disorders of nose and nasal sinuses	❌
J95.89	Other postprocedural complications and disorders of respiratory system	❌
Q30.0	Choanal atresia	❌
Q30.1	Agenesis and underdevelopment of nose	❌

Hand / Tendon Gliding Surface Restoration

ICD-10-CM	Description	HCC?
M65.9	Synovitis and tenosynovitis, unspecified	❌
M66.359	Spontaneous rupture of flexor tendons, unspecified hand	❌
S62.001A	Fracture of distal pole of navicular bone of right wrist, initial	❌
T71.9XXA	Asphyxiation, unspecified, initial	❌
M72.0	Palmar fascial fibromatosis (Dupuytren)	❌
S66.001A	Unspecified injury of long flexor muscle, right thumb, initial	❌

Chronic Wounds / Osteomyelitis

ICD-10-CM	Description	HCC?
M86.9	Osteomyelitis, unspecified	✅ HCC 39
M86.172	Other acute osteomyelitis, left ankle and foot	✅ HCC 39
M86.672	Other chronic osteomyelitis, left ankle and foot	✅ HCC 39
L89.159	Pressure ulcer of sacral region, unspecified stage	❌
L97.419	Non-pressure chronic ulcer of right heel and midfoot	❌
E11.621	Type 2 diabetes with foot ulcer	✅ HCC 18

Status / Encounter Codes

ICD-10-CM	Description	HCC?
Z42.8	Encounter for other plastic/reconstructive surgery following healed injury	❌
Z87.39	Personal history of other musculoskeletal disorders	❌
Z85.819	Personal history of malignant neoplasm of unspecified site	❌
Z90.01	Acquired absence of eye	❌

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🏨 MS-DRG Mapping

Inpatient Context

In the inpatient hospital setting, procedures are coded in ICD-10-PCS — CPT codes are not assigned. The nature and complexity of the underlying principal diagnosis and associated CC/MCC burden drive DRG assignment. Free fascial flap reconstruction maps across several DRG families.

Head, Face & Skull Reconstruction

MS-DRG	Description	Approx. Relative Weight
168	Major Head & Neck Procedures w/ MCC	~3.8–4.2
169	Major Head & Neck Procedures w/ CC	~2.5–2.9
170	Major Head & Neck Procedures w/o CC/MCC	~1.8–2.1

Skin / Soft Tissue Reconstruction

MS-DRG	Description	Approx. Relative Weight
573	Skin Graft and/or Debridement w/ MCC	~3.7–4.5
574	Skin Graft and/or Debridement w/ CC	~2.2–2.6
575	Skin Graft and/or Debridement w/o CC/MCC	~1.5–1.8

Ear, Nose & Throat

MS-DRG	Description	Approx. Relative Weight
154	Other Ear, Nose, Mouth & Throat OR Procedures w/ MCC	~3.1–3.6
155	Other Ear, Nose, Mouth & Throat OR Procedures w/ CC	~2.0–2.4
156	Other Ear, Nose, Mouth & Throat OR Procedures w/o CC/MCC	~1.4–1.7

Hand & Upper Extremity Procedures

MS-DRG	Description	Approx. Relative Weight
510	Shoulder, Elbow, or Forearm Procedures w/ MCC	~2.8–3.2
511	Shoulder, Elbow, or Forearm Procedures w/ CC	~1.8–2.1
512	Shoulder, Elbow, or Forearm Procedures w/o CC/MCC	~1.2–1.5

Eye / Orbital Procedures

MS-DRG	Description	Approx. Relative Weight
124	Other Disorders of the Eye w/ MCC	~1.8–2.2
125	Other Disorders of the Eye w/o MCC	~1.1–1.5

DRG Capture Tip

For fascial free flap cases driven by orbital malignancy (e.g., C69.61) or skull base neoplasm (e.g., C41.0), ensure that all complicating comorbidities — prior radiation sequelae, wound dehiscence, active infection, nutritional deficiency — are coded and documented. These shift cases into MCC-weighted DRG tiers, representing meaningful reimbursement increases. Query the surgeon and review nursing and therapy notes for clinically supported but uncoded diagnoses.

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🌳 CPT Code Tree — Free Flap Family

Free Flaps with Microvascular Anastomosis
├── 15756 — Free MUSCLE or MYOCUTANEOUS flap
│     └── Tissue: Muscle only OR Muscle + overlying skin
│
├── 15757 — Free SKIN / FASCIOCUTANEOUS flap
│     └── Tissue: Skin + subcutaneous fat ± investing fascia (NO muscle)
│
└── 15758 ← FREE FASCIAL FLAP (THIS CODE)
      └── Tissue: Fascia ONLY — no skin paddle, no muscle

Related Pedicle / Local Flap Codes (not free flaps):
├── 15732 — Muscle/myocutaneous flap, head & neck (pedicle)
├── 15733 — Muscle/myocutaneous flap, upper extremity (pedicle)
├── 15740 — Island pedicle flap
└── 15750 — Neurovascular pedicle flap

Ancillary / Companion Codes Frequently Paired:
├── 15100 — STSG, trunk/arms/legs (skin graft over fascial flap surface)
├── 15115 — STSG, face/scalp/eyelids (skin graft over fascial flap surface)
├── 21230 — Rib cartilage graft for auricular reconstruction (microtia)
├── 64905 — Nerve pedicle transfer, first stage
└── 64907 — Nerve pedicle transfer, second stage

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🗂️ ICD-10-PCS Context (Inpatient Coding)

Inpatient Coder Note (CIC Relevance)

In the inpatient acute care setting, CPT codes are not assigned. All procedures are coded in ICD-10-PCS. A free fascial flap, where the tissue is completely detached and re-vascularized through microsurgical anastomosis, is coded under the Replacement root operation — the tissue substitute is autologous (device value: 7), and the body part reflects the recipient site.

General ICD-10-PCS axis logic — free fascial flap:

Axis	Value
Section	0 – Medical & Surgical
Body System	J – Subcutaneous Tissue and Fascia (donor site); or H – Skin and Breast / N – Head & Facial Bones region (recipient site)
Root Operation	R – Replacement (recipient site)
Body Part	Specific recipient anatomical location
Approach	0 – Open
Device	7 – Autologous Tissue Substitute
Qualifier	Z – No Qualifier (site-dependent)

Two-Code Rule for Free Fascial Flaps in ICD-10-PCS

Assign separate ICD-10-PCS codes for:

1. Donor site — typically an Excision (root operation B) of fascia from the harvest location (e.g., scalp/temporal fascia, forearm fascia). Body system: J – Subcutaneous Tissue and Fascia.
2. Recipient site reconstruction — Replacement (root operation R) with autologous tissue substitute at the defect location.

Additionally, if a split-thickness skin graft is placed over the fascial flap in the same operative session, assign a third ICD-10-PCS code for the skin replacement at the recipient site surface.

The microvascular anastomosis itself is not separately coded in ICD-10-PCS — it is considered integral to the open approach of the Replacement root operation.

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📝 Coding Examples

Example 1 — Microtia Reconstruction with TPF Free Flap (Otolaryngology / Plastic Surgery)

Clinical Scenario: A 9-year-old patient with right unilateral microtia (Grade III) undergoes staged ear reconstruction. In this session, a rib cartilage framework is carved and a right temporoparietal fascial (TPF) free flap is elevated, detached from its superficial temporal artery/vein pedicle, and microsurgically anastomosed to recipient vessels over the newly placed framework. A split-thickness skin graft from the right groin is applied over the fascial surface.

CPT Codes:

• 15758 — Free temporoparietal fascial flap with microvascular anastomosis
• 21230 — Rib cartilage graft for reconstruction of ear, nose, eyelid, and/or lip (modifier -51)
• 15100 — STSG, trunk (groin donor STSG applied over fascial flap surface) (modifier -59)

ICD-10-CM:

• Q17.2 — Microtia (principal)
• Q16.0 — Congenital absence of auricle

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Example 2 — Orbital Reconstruction Post-Exenteration (Ophthalmology / Oculoplastics)

Clinical Scenario: Patient with left orbital squamous cell carcinoma undergoes left orbital exenteration. Oculoplastic and reconstructive surgery team reconstructs the orbital cavity using a free radial forearm fascial flap microsurgically anastomosed to the facial artery and vein, providing thin, well-vascularized fascial lining of the orbit. STSG placed over the fascial surface at the time of flap inset.

CPT Codes:

• 65112 — Exenteration of orbit with therapeutic removal of bone (primary procedure)
• 15758 — Free radial forearm fascial flap with microvascular anastomosis (modifier -51)
• 15115 — STSG, face/scalp/eyelids (STSG over fascial orbital lining) (modifier -59)

ICD-10-CM:

• C69.62 — Malignant neoplasm of left orbit (principal) (HCC 11)
• Z79.01 — Long-term use of anticoagulants (if applicable)

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Example 3 — Nasal Lining Reconstruction (Otolaryngology / Head & Neck)

Clinical Scenario: Patient with extensive nasal SCC requiring total rhinectomy. After tumor extirpation, a free temporoparietal fascial (TPF) flap is harvested and used to resurface the internal nasal lining. A second free flap (15757 — ALT fasciocutaneous) provides the external skin envelope. Microvascular anastomosis performed for both flaps to facial vessels.

CPT Codes:

• 15758 — Free TPF fascial flap for internal nasal lining (microvascular anastomosis)
• 15757 — Free ALT fasciocutaneous flap for external nasal skin envelope (modifier -51)
• Rhinectomy/resection code (modifier -51)

ICD-10-CM:

• C30.0 — Malignant neoplasm of nasal cavity (principal) (HCC 11)

Billing Two Free Flaps Same Session

When two distinct free flaps are performed in the same operative session at different recipient sites (or serving different reconstructive purposes at the same site), both may be reportable — append modifier -51 to the lesser-valued procedure (15758) and modifier -59 as appropriate per NCCI. Document clearly in the operative report that two distinct flap harvests and two separate microvascular anastomoses were performed.

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Example 4 — Hand / Tendon Gliding Surface Reconstruction

Clinical Scenario: Patient with extensive dorsal hand burn with loss of tendon gliding surface and extensor mechanism scarring. After scar excision, a free serratus anterior fascial flap (fascia only, no muscle) is microsurgically anastomosed to the radial artery and cephalic vein at the wrist. STSG is applied over the fascial surface.

CPT Codes:

• 15758 — Free serratus fascial flap with microvascular anastomosis
• 15100 — STSG, trunk/arms/legs (applied over fascial surface, hand/dorsum) (modifier -59)
• 16035 — Escharotomy (prior session — not billed same day unless documented separately and medically distinct)

ICD-10-CM:

• T23.301A — Burn of third degree of right hand, unspecified site, initial encounter (principal)
• T31.20 — Burns involving 20–29% of body surface with 0% third-degree burns (if total TBSA documented)

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Example 5 — Skull Base Reconstruction (Neurosurgery / Otolaryngology)

Clinical Scenario: Patient with recurrent nasopharyngeal carcinoma and skull base erosion after prior chemoradiation undergoes skull base resection. Neurosurgery and ENT collaborate. A free temporoparietal fascial flap is harvested and used to reconstruct the skull base dural layer and obliterate dead space, with microvascular anastomosis to the superficial temporal artery at a recipient branch.

CPT Codes:

• 15758 — Free TPF fascial flap with microvascular anastomosis for skull base reconstruction
• Skull base resection code (modifier -51)
• Dural repair code (verify NCCI bundling — may be separately reportable with -59)

ICD-10-CM:

• C11.9 — Malignant neoplasm of nasopharynx, unspecified (principal) (HCC 11)
• Z85.819 — Personal history of malignant neoplasm (use only if disease-free; use active code if still under treatment)
• Y83.6 — Surgical procedure as cause of abnormal reaction (if radiation sequelae contributing)

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Example 6 — Return to OR During Global Period (Anastomotic Failure)

Clinical Scenario: Patient POD #2 following free TPF fascial flap for auricular reconstruction loses Doppler signal. Taken back emergently — venous anastomosis found thrombosed. Anastomosis revised with vein graft interposition.

CPT Codes:

• 15758 with modifier -78 — Return to OR for related procedure during postoperative period
• 35500 — Harvest of vein for vein graft interposition (verify NCCI; append modifier -59 if separately documented and identifiable)

ICD-10-CM:

• T87.9 — Complication of reattached body part, unspecified
• Q17.2 — Microtia (underlying condition from index surgery)

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⚠️ Common Coding Pitfalls

• 15757 vs. 15758 — the #1 error: If any skin paddle was included in the flap harvest — even a small pinch of skin used as a monitor — the correct code is 15757, not 15758. 15758 is strictly for fascia-only transfers. Read the operative report tissue description carefully.
• Secondary STSG is not bundled: The split-thickness skin graft placed over the fascial surface is separately reportable (15100 or 15115). Failure to capture this secondary graft results in lost revenue. Append modifier -59 and verify NCCI.
• TPF flap laterality: Use modifiers -LT or -RT when the laterality of the recipient site or donor site is clinically determinable and payer-required.
• Modifier -22 documentation: Prior radiation to the head and neck is the most common justification for modifier -22 in 15758 cases involving skull base or pharyngeal reconstruction. The operative note must describe specific challenges encountered — not merely note a history of radiation. Attach a cover letter to the claim.
• Inpatient coding: Never assign 15758 for an inpatient hospital stay. Use ICD-10-PCS with root operation Replacement, body system J (Subcutaneous Tissue and Fascia) or appropriate recipient body system, and device 7 (Autologous Tissue Substitute).
• Staged procedures: When microtia reconstruction occurs across multiple surgical sessions (framework placement, TPF flap, ear elevation), each session is coded separately. Do not attempt to bundle into a single code. Use modifier -58 (staged procedure) to indicate planned staging within the global period.
• Pediatric patients: Microtia reconstruction with 15758 is commonly performed in pediatric patients. Payer authorization requirements vary — verify prior auth, especially for commercial pediatric plans, before scheduling. Document the functional and reconstructive (not cosmetic) indication clearly.
• Do not separately bill the microvascular anastomosis: The anastomosis is integral to 15758 — it is not a separately billable service.

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📚 Brief Source References

^{AMA CPT Professional Edition 2025, codes 15756–15758 and integumentary surgery guidelines CMS Medicare Physician Fee Schedule Final Rule 2025 – RVU and payment indicator files (www.cms.gov/Medicare/Medicare-Fee-for-Service-Payment/PhysicianFeeSched) CMS NCCI Policy Manual for Medicare Services, Chapter 7: Surgery – Skin, Subcutaneous & Accessory Structures, 2025 CMS MS-DRG Definitions Manual v41 FY2024, Chapters 3 and 6 – Head/Neck and Skin DRGs ICD-10-PCS Official Guidelines for Coding and Reporting FY2025, Section B3 – Root Operations (Replacement, Excision) ICD-10-CM Official Guidelines for Coding and Reporting FY2025, Section I.C.2 – Neoplasms; Section I.C.19 – Injury and Burns AAPC CPC/CIC Study Guide – Integumentary & Reconstructive Surgery chapters Pribaz JJ, Orgill DP. Temporoparietal Fascial Flap. Flaps and Reconstructive Surgery, 2nd ed. Wei FC, Mardini S, eds. Elsevier 2017 Mathes SJ, Nahai F. Reconstructive Surgery: Principles, Anatomy & Technique. Churchill Livingstone 1997 – Fascial and Fasciocutaneous Free Flap chapters}