Subcision for acne scars: releasing fibrous tethering to lift depressed scars

Subcision is a minimally invasive technique for treating depressed acne scars — particularly rolling and some boxcar scars — by mechanically cutting the fibrous bands tethering the scar floor to the underlying dermis. Released from their tethers, the scars elevate toward the skin surface. It was first described by Orentreich and Orentreich in 1995 and remains one of the most effective and frequently performed procedures for depressed acne scarring. Here is the complete guide.

The mechanism: fibrous tethering and subcision release

Why rolling scars are depressed

Depressed acne scars — particularly rolling scars — are not simply areas of lost volume. The scar base is physically tethered to the deep dermis and subcutaneous tissue by fibrous bands: columns of dense collagen and fibrous tissue that formed during the wound-healing response to severe inflammatory acne. These bands:
Pull the overlying scar base downward from beneath
Prevent normal elevation of the scar floor
Cannot be released by topical treatments, laser, or filler alone

Topical retinoids and laser can improve scar texture and stimulate collagen in the scar walls — but they cannot cut the fibrous tethers holding the scar floor down. Volume added with filler is pushed back into the skin from above — temporarily, before the tether reasserts the depression. Subcision cuts the tether.

The subcision mechanism

A needle or blunt-tip cannula is inserted through the skin adjacent to the scar, advanced under the scar base in the subdermis, and moved back and forth with a fanning motion — mechanically severing the fibrous tethering bands.

Two effects:
Immediate release: The scar floor is freed from downward tension → immediate partial elevation of the depressed scar
Post-subcision fibroplasia: The mechanical trauma of subcision + the blood pooling in the subcised space (a hematoma forms under the treated scar) creates a wound-healing response — fibroblasts migrate into the hematoma and lay down new, organized collagen → the scar floor is elevated from below by new tissue formation over 4–8 weeks

The hematoma as scaffold: The pooled blood under subcised scars is intentional. It provides the fibrin scaffold into which fibroblasts migrate. Aspirating the hematoma (which some providers do to reduce bruising) partially defeats this mechanism. Many experienced subcision practitioners deliberately leave the hematoma in place.

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Needle vs. cannula subcision

Needle (Nokor needle, 18-gauge tri-bevel)

The original Orentreich technique used a standard hypodermic needle. The Nokor needle — a specific tri-bevel design — cuts more efficiently through fibrous tissue.

Advantages: More precise; better for focal, discrete scars; more cutting force for dense fibrous bands.

Disadvantages: Sharp tip; higher risk of hematoma beyond the scar base; more discomfort; requires topical + local anesthetic.

Cannula subcision (blunt-tip microcannula)

Blunt-tip cannulas are increasingly used for subcision — the blunt tip dissects through tissue planes rather than cutting, reducing hematoma formation beyond the treatment zone.

Advantages: Reduced bruising; can treat larger areas per entry point; lower risk of inadvertent vessel puncture.

Disadvantages: Less effective for very dense fibrous tethers; requires larger entry points.

Current practice: Many providers use cannula for broader rolling scar areas and needle (Nokor) for focal boxcar scars with dense tethering.

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Scar types and subcision response

Rolling scars — primary indication

Rolling scars are the best candidates for subcision. Their mechanism — fibrous band tethering to the deep dermis — is precisely what subcision addresses.

Improvement per session: 20–40% elevation in scar depth per session; typically 2–4 sessions at 4–8 week intervals for meaningful improvement.

Boxcar scars — partial indication

Boxcar scars have steep vertical walls and a flat floor. The fibrous tethering component is less universal — some boxcar scars benefit from subcision (those with a tethered floor); others with sharply defined edges require TCA CROSS (trichloroacetic acid chemical reconstruction of skin scars) or punch elevation/excision for the wall component.

Ice pick scars — not indicated

Ice pick scars are narrow, deep epidermal tunnels. Their narrow diameter (< 1 mm) means subcision cannot effectively treat them — the needle cannot maneuver within the scar tract. TCA CROSS is the primary treatment for ice pick scars.

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Combining subcision with other treatments

Subcision + filler

The most common combination: subcision releases the tether; HA filler injected immediately into the subcised space:
Provides immediate structural support to prevent re-tethering
Adds volume to the scar floor to further elevate it
The filler occupies the space where the hematoma would form — some providers use this; others prefer to allow natural hematoma formation

Timing: Filler can be placed in the same session (immediately post-subcision) or at 4–6 weeks when the subcision-induced tissue response has stabilized.

Subcision + RF microneedling (sequencing)

Subcision addresses the tethering; RF microneedling addresses scar texture and wall irregularity. Optimal sequencing:
Subcision first — release tethers; allow 4–8 weeks for fibroplasia
RF microneedling (Morpheus8, Genius) — improve overall scar texture, reduce wall depth, stimulate broader collagen remodeling

Performing RF microneedling before subcision is less effective — the scar is still tethered; thermal collagen stimulation in a tethered scar contributes less to elevation.

Subcision + TCA CROSS

For mixed scar morphology (rolling + ice pick on the same patient), subcision treats rolling scars and TCA CROSS is applied to ice pick scars in the same or sequential sessions.

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The treatment experience

Anesthesia

Subcision is performed under:
Topical anesthetic (EMLA 45–60 min): Reduces surface discomfort
Local infiltration anesthetic (lidocaine with epinephrine): The most effective — injected into the subcutaneous tissue beneath the scars to be treated; produces full anesthesia of the treatment zone; epinephrine reduces bleeding during the procedure

The procedure is well-tolerated under adequate local anesthesia; patients report pressure sensation rather than sharp pain.

Post-procedure

Bruising: Significant bruising is expected — the mechanism depends on hematoma formation. The treated areas are purple-black for 7–14 days. This is normal and expected; patients must be counseled before treatment.

Swelling: Edema peaks at 24–48 hours; resolves within 5–7 days.

Social downtime: 5–14 days depending on scar density and extent of treatment.

Post-procedure care: No active exercise for 48 hours (to limit hematoma extension); SPF protection; avoid pressure on treated areas. No massage of treated areas — allows hematoma fibroplasia to proceed.

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Realistic expectations by protocol

| Protocol | Sessions | Improvement in Rolling Scar Depth | Durability |
|---|---|---|---|
| Subcision alone | 2–4 × 6 weeks | 30–50% per course | Long-lasting (new collagen) |
| Subcision + filler | 1–2 + maintenance filler | 50–70% initial; maintain with filler | Filler 12–18 months; structural improvement long-lasting |
| Subcision + RF microneedling | 2–3 each | 60–80% improvement (combined) | Long-lasting |
| Subcision + TCA CROSS (mixed) | 3–4 each | 50–70% (type-specific) | Long-lasting |

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