A 2026 split-face trial found suction-assisted subcision scored higher than subcision alone for atrophic acne scars, which include boxcar scars. Subcision uses a needle or cannula under the skin to release tethered scars, while suction adds vacuum lifting to that side. Both approaches improved scars, so the choice is not between a treatment that works and one that does not. The added suction offered extra improvement in doctor and patient ratings.
Medical information disclaimer: This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a physician or other qualified health professional about symptoms, medications, tests, or treatment decisions.
Table of Contents
- How the trial tested suction
- Why suction may help boxcar scars
- Why the benefit looked subjective
- What to ask your dermatologist
How the trial tested suction
The trial enrolled people with atrophic acne scars and treated one cheek with subcision alone and the other cheek with suction-assisted subcision, according to the U.S. National Library of Medicine PubMed in the trial record.
This within-patient design compared healing on two sides of the same face. Both sides showed significant improvement after treatment. Physician-rated and patient-rated Acne Scar Improvement Grading Scale scores were significantly higher on the suction-treated side, with p=.002 and p=.026 respectively.
Why suction may help boxcar scars
Boxcar scars are round-to-oval depressions with sharp vertical walls and flat bases. Westlake Dermatology describes subcision as highly effective for moderate-to-severe rolling and tethered boxcar scars, often combined with other treatments.
Subcision cuts fibrous bands that pull the scar surface down, freeing the surface to lift and stimulating collagen. Added suction or vacuum massage lifts the released scar and is proposed to prevent early redepression, according to the U.S. National Library of Medicine PMC review in this scar-treatment review.
Why the benefit looked subjective
The trial authors concluded subjective assessments favored suction-assisted subcision, suggesting benefits patients and doctors can see that scar counts alone may miss. An earlier Northwestern split-face, rater-blinded trial points to caution. In 28 treatment areas, blinded dermatologists found no difference at 1 and 4 months, while a patient-reported 37%-versus-24% edge for suction at 1 month faded by 4 months, according to the Research Square preprint record in the preprint summary.
What to ask your dermatologist
Boxcar depth, width, tethering, skin tone, and prior procedures shape whether suction is worth adding. Bring photos of your scars in overhead and angled light and ask how your pattern compares with trial-type atrophic scars. Use the answers to weigh cost, visits, and downtime against a possible visible boost.
- Ask how many extra suction or massage visits the clinic uses
- Ask about bruising, swelling, and days away from work or school
- Ask whether faster perceived smoothing justifies suction rather than expecting guaranteed extra clearance
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- Subcision With Suction for Acne Scars in a 2026 Split-Face Trial: What Longer Follow-Up Must Show for People With Rolling Acne Scars
- The 160-Participant Acne Scar Combination Trial Published in 2026: What the Trial Means for People With Boxcar Acne Scars
- Objective vs Patient-Rated Results in the 2026 Subcision Trial: What Longer Follow-Up Must Show for People With Rolling Acne Scars