CO2 Pinhole Technique — Holes, Not Ablation

Three-line summary

• The pinhole technique is not a treatment that shaves a scar away but one that makes holes in it. An ablative CO2 laser creates fine holes reaching from the epidermis into the deep dermis, dividing fibrotic tissue into separate compartments and prompting collagen bundles to re-align through healing.
• The delivery differs from fractional CO2. A fractional device fires beams at fixed spacing inside a set grid, so it passes through normal skin along the way; pinhole selects the points where fibrosis is dense and fires one shot at a time. The beam therefore goes deeper and disturbs normal skin less.
• Downtime and pigment care are the premise. Because holes are made, about a week of crusting is needed, and in skin of color post-inflammatory hyperpigmentation (PIH) can follow. It is usually spread across sessions rather than finished in one.

What the pinhole technique is

It helps to start with what scar treatment is aiming at. Scar treatment is not treatment that erases a scar. The goal is to make the scar as little noticeable as it can be, and to make the texture of the skin smoother. Once that premise slips, any treatment leaves nothing behind but a sense of falling short of expectations.

The pinhole technique is, as the name says, a way of making many holes the size of a pin prick in a scar. A CO2 laser beam is fired into scar tissue one shot at a time, creating holes that start at the epidermis and run into the deep dermis, dividing the fibrotic part. It is closer to punching channels dot by dot into the hardened places than to burning the scar across its whole surface.

What happens in a scar once holes are made

The problem in scar tissue is not that collagen is absent but that collagen is arranged wrongly. In normal skin collagen is interwoven in many directions, so it gives flexibly when pulled; in scar tissue collagen is packed down tightly in a single direction. That is why the scar looks a different color, reflects light differently, feels firm to the touch, and does not move together with the skin around it.

People often think of a scar standing out purely as a matter of color, but in practice the difference in how light is reflected frequently counts for more. A surface whose collagen is aligned in one direction returns light unlike the skin around it, so covering the color with makeup still leaves the site showing under lighting. This is where people find themselves when the color has already come to match the surrounding skin almost exactly and yet the scar keeps showing. It is a type that rarely settles unless texture is addressed.

Making holes with pinhole sets three things going at once. First, collagen bundles re-align along the holes. Second, dermal thickness improves through healing, so depressions and raised parts of the surface become gentler. Third, fibrotic tissue that ran long and continuous is divided into compartments, so the tension the scar was under drops. The third does not show on the surface but matters in practice. The pull of one long continuous band, and the pull of several separate pieces each holding their own, appear on the skin surface as entirely different shapes.

Energy and pulse width decide the result

Two things are adjusted in the pinhole technique. Energy determines the depth of the hole, and pulse width determines how far thermal damage extends into the tissue around it. Too little depth and the beam never reaches the hardened layer, touching the surface and no more; too much depth and healing carries a risk of producing a fresh scar. With the same device and the same technique, the result changes according to how these two values were set.

So the pinhole technique is not a treatment along the lines of "run this mode on this device". It is closer to treatment that reads the firmness and thickness of each individual scar and sets values to suit that place. Even within one scar, the settings at the center and at the edge often differ.

Why holes rather than shaving

The first thought that comes to mind with a raised scar is "it sticks out, so surely you shave it flat". Lowering the height by vaporizing the surface with a laser — ablation — has in fact been in use for a long time, and is still used as the situation calls for it. This route has a structural limit, though.

The limits of shaving

• The height comes down but the nature stays — what makes a raised scar is not the part standing above the surface but the fibrotic tissue hardened beneath it. Shave the surface alone and the height drops while the fibrosis underneath remains, so it can rise again over time.
• The shaved area becomes a fresh wound — vaporize the whole surface across a wide area and a new wound is made over that same area. How that wound heals again rests on the individual's healing tendency, and the outcome may be to exchange the original scar for a scar of a different form.
• There is little room for it in pale scars — some scars are white and barely raised, yet stand out because the texture of the surface differs. In these there is almost no height to shave off.

What making holes does differently

Pinhole does not remove the surface across a wide area. Undamaged tissue remains like islands between hole and hole, and this remaining tissue is the starting point for healing. So although the same CO2 laser is used, recovery is quicker than with a method that vaporizes the whole surface, and there is relatively less room for a new scar to form.

Another advantage is that exactly the points you want can be selected. Feel a scar and it is not uniformly firm throughout. There are points balled up unusually hard, and points that have already come close to the surrounding skin. Pinhole fires one shot at a time at the points that need dividing, so the parts that need no touching can be left as they are.

This is different in kind from scar revision surgery

Among the ways of dealing with a scar there is also the surgical route of excising it and re-suturing along a changed direction (Z-plasty and the like). That approach changes the direction of the scar and the tension on it, so its purpose differs from pinhole, and there are clearly situations that call for it. By its nature, though, it adds a new incision line in normal skin and lengthens recovery. ABLE Dermatology does not perform scar excision surgery, and plans around lasers and injectable treatments. This is not to say that either is better, but that the choice divides according to whether the situation is one where downtime and an additional incision are worth accepting.

How it differs from fractional CO2

Taken purely as "make holes to drive collagen regeneration", the fractional CO2 laser and the pinhole technique sound like the same account. The broad principle does overlap. The difference lies in where the beam is delivered, how large it is, and how deep it goes.

With fractional CO2 a scanner fires beams automatically at fixed spacing inside a set shape. It is designed to handle a wide area evenly, and because safety comes first, on most devices the beam is very small and its depth of reach is limited. Beams also pass through normal skin, not the scar alone, wherever it falls inside the grid. This method suits problems that cover a wide area, such as widespread acne scarring or pores.

Pinhole is the reverse. Even within a lesion, the points where fibrosis is dense enough to be worth dividing are selected and fired one shot at a time. Each shot carries enough energy and goes deep, while in exchange the operator has to set every position individually. It is a method that takes depth and precision instead of area.

One thing to add: the beam of a fractional device being small and shallow is a design choice rather than a limit of the machine. It has to sweep a wide area automatically and stay safe, so the force of each shot was lowered. Pinhole does the reverse, raising the force of each shot while the operator sets each position by hand. Pinhole therefore carries more recovery burden than fractional, and fractional reaches the hardened layer with less force than pinhole. Neither is the better technology; they are designs that differ in what was given up and what was taken.

The table makes pinhole look like the stronger treatment, but the two do not replace each other. Try to handle scarring spread widely across the face with pinhole alone and neither the time nor the recovery burden is manageable; repeat fractional alone on a scar hardened at a few spots and the hardened layer is just what never gets reached. In practice the most common arrangement is to put both into one plan — fractional for the broad area, pinhole for the hardened points.

Which scars pinhole is used on

Where the pinhole technique finds its place is fairly clear. Scars that have faded to white and are not greatly raised, yet stand out because the texture of the surface differs. Scars like these sit in a band that is hard to handle either with the treatments used for depressed scars or with those used for markedly raised ones.

Scars that sit between the established treatments

Scar treatment has developed along two broad lines. For depressed scars there are treatments that lift the sunken place or release tethering — subcision, fractional CO2, microneedle RF, filler. For markedly raised scars, medication is injected into the lesion or the height is lowered by shaving the surface, with a vascular laser used alongside where redness is strong.

The difficulty is the scar that sits between these two lines. Neither greatly depressed nor greatly raised, the color already faded, but the texture of the surface distinctly different. There is nothing much to lift, nothing to shave, no color to take out, so it ends up in a state where the established treatments have no clear place to work. This is exactly where the pinhole technique is used. Instead of changing the height, it divides the hardened tissue itself into compartments, working in the direction of drawing the surface texture toward the surrounding skin.

Surgical and suture scars

For a scar left by surgery or suturing it is understood to be better to begin care right after the sutures come out. At that stage the scar is still in the process of hardening, so there is room to intervene in how it settles, with fractional CO2 or regenerative injections. If you have surgery ahead of you, it is worth coming for a consultation as soon as the stitches are out.

A scar that has had time pass, though, usually remains as a white, firm line. Neither pigment treatment nor redness treatment takes hold on it, and there is no height to shave away. At this stage the pinhole technique becomes an option: dividing the hardened line into compartments to lower tension, and through healing drawing the texture of the surface toward the surrounding skin.

Burn scars

Burn scars are on the difficult side. Fibrosis progresses over a wide area and the movement of the tissue around the scar can itself be restricted, and symptoms such as tightness and discomfort can be more of a burden than the visible problem. Scars like these are not approached with a single treatment.

There are reports that a combination helps: handling texture over the broad area with fractional CO2, and adding pinhole at the points that have hardened most. If redness remains, V-Beam is placed alongside; where pigment is present as well, a pigment laser; and subcision (Trifill) or regenerative injections are added as needed. Rather than a treatment that reverses things, it is realistic to plan it as treatment that reduces discomfort and visibility across sessions.

Papular acne scars

The slightly raised form left where acne once sat is called a papular scar. The name leads some people to group it with keloids and hypertrophic scars, but a papular scar is understood to be a different form from these. Unlike a keloid, which swells red and firm, it is often close to skin color with a softly raised surface.

There are several reports of the pinhole technique helping with this form of scar. In practice it is more often used together with other lasers than on its own. Acne scarring usually has depressed and raised scars, red marks and brown marks mixed within one face, so dividing the work up by form is what decides the result. Telling keloids apart from hypertrophic scars, and the approach to each type of depressed scar, are covered separately in other columns.

If marks from the past are on your mind

Some people have marks left long ago on parts that are often visible, such as the forearm or the wrist, and find them weighing on them. In consultation we do not ask how the mark came about. What we check is the state of the skin now — what color it is, how far the surface differs from the skin around it, how firm the tissue is. If time has passed, the color has faded and it is the surface alone that differs from its surroundings, the pinhole technique can be one of the options; if redness remains, V-Beam may be placed first, and where pigment is present as well, a pigment laser. It is not treatment that returns the skin to how it was in one go, but working across sessions we take making it less noticeable as the goal, and coming just for a consultation is perfectly all right. If things are weighing heavily on you at the moment, though, we would suggest getting professional support alongside, ahead of skin treatment.

Uses beyond scars

Pinhole is not a technique used on scars alone. The principle of reaching tissue by making holes applies to other lesions too.

• Sebaceous hyperplasia — usually handled by tidying the raised part with a CO2 laser and expressing the contents. There is research showing improvement from making holes with pinhole and then expressing alone, so the two are sometimes used together as the situation calls for it. As a lesion that comes with age, recurrence is common.
• Syringoma under the eyes — treatment using radiofrequency is known, and tidying with a CO2 laser is also used. There are reports of approaching it with the pinhole technique. Whichever route is taken, though, recurrence is common, and we say so before starting.
• Dilated vessels — as a rule a vascular laser such as V-Beam comes first. In forms that are hard to handle with a vascular laser, the pinhole method is sometimes used.

There are sites pinhole does not suit

The first caution to raise about the pinhole technique is that depending on the site, a scar can go the other way and worsen. This is less a side effect than a limit arising from the nature of the technique.

Sites with a lot of movement and tension

There are positions pulled continuously when you speak or make an expression. Below the philtrum is the typical one, and the same goes for areas around joints, or skin that is constantly under tension. A scar at such a site is pulled on throughout healing, so while the holes close the scar can go in the direction of widening or standing out more.

So at these sites we change the conditions of the approach. We set the depth lower and add sessions, or work in parts rather than over a wide area at once, or where needed proceed with movement in that muscle reduced by botulinum toxin. In effect, the situation of the expression muscles pulling continuously at the scar is reduced first, before starting.

Going deeper is not automatically the answer

The explanation that "it works better the deeper it goes" is half right and half wrong. It is true that reaching the hardened layer is what gives it meaning, but past that point it crosses over into producing a new scar through healing. In thin skin especially, and where the tissue beneath the scar has already thinned, where the depth stops is what decides the result.

We do not try to do it all at once

The urge is to perforate the whole scar densely in one go, but as hole density rises the recovery burden and the likelihood of pigmentation rise with it. With a wide scar it is often safer in the end to work zone by zone, or to lower the density and add sessions. In scar treatment, a choice to raise the intensity in haste tends to be paid for at the recovery stage.

Healing and pigmentation — what to watch for in skin of color

Pinhole genuinely makes holes in the skin. So the account of the healing process matters more here than with other laser treatments. Immediately afterwards a very small dot-shaped crust forms at each point treated, and about a week of downtime is set aside as a rule.

The procedure itself is carried out under anesthetic cream or local anesthesia, and how long it takes varies with the number of points treated. Working densely over a wide scar takes correspondingly longer; a few points on a small scar finish quickly. Heat and stinging can be felt right afterwards, though these generally settle within a day, and how much is felt differs between individuals.

What to keep to during recovery

• Keep water off the area — while crusts are in place, the basic rule is not to let water get directly into the treated area. How to wash your face or shower is explained separately according to the site.
• Do not pick the crusts off — this is the most common mistake. Take a crust off early and a surface that has not finished healing is exposed, which makes pigment more likely to linger. Waiting until they come away on their own is the better care.
• Keep the area from drying out — holding a moist environment with the prescribed ointment and moisturizer makes healing easier.
• Avoid irritation — saunas, steam rooms and strenuous exercise are better put off through the recovery period.

Post-inflammatory hyperpigmentation (PIH) is something to know before starting

This is the part to be straightforward about in the pinhole technique. Post-inflammatory hyperpigmentation can follow, with a brown tone coming up at the points where holes were made. Skin of color, Fitzpatrick III-IV in particular, has an active melanin response, so for the same procedure the tendency for pigment to linger is understood to be more marked than in lighter skin types. This is less a problem arising from something going wrong in the procedure than a response that comes from the skin type.

Pigmentation tends to appear some weeks after the procedure, hold for a while, then fade gradually. How dark it comes up and how long it lasts varies a great deal between individuals, and depends on how far recovery care and sun protection were kept to. Knowing this process before starting, and meeting a brown tone without having known, are entirely different experiences.

What we actually do to reduce pigment

• Sun protection — the center of aftercare. Even once the crusts have come away, keeping to sunscreen for at least a few months is better, and where possible covering the area directly with a hat or clothing is used alongside.
• Choosing the timing — rather than treating a wide area in a season of heavy UV exposure, placing sessions in a period of less exposure is favorable where the schedule allows. That goes doubly for sites that are hard to cover, such as the forearms or the backs of the hands.
• Adjusting density against recovery — as said above, the denser a single session, the greater the pigment burden. Lowering the density and adding sessions can be favorable for pigment management too.
• Clearing pigment that has already appeared — if pigment remains, a treatment addressing it is placed separately. At ABLE Dermatology we run PicoPlus and Spectra as the pigment axis, and while pigment is clearing we adjust the interval to the next pinhole session.

To add, we do not advise layering a strong pigment treatment on in haste at the point pigment comes up. Add irritation to skin that is still healing and pigment can last longer. Reading what stage the pigment is at and setting when to intervene comes first in the order.

Session planning — this is not a treatment finished in one visit

Surface texture does change after a single session of the pinhole technique in some cases, but when a plan is drawn up it is set on the premise of three or more sessions as a rule. The aim is not to divide all the hardened tissue at one go, but to layer the cycle of dividing, healing and re-aligning several times over.

What sets the interval

The timing of the next session is set by the state of the skin, not the calendar. We look at whether the crusts have all come away, whether redness has settled, whether pigment has come up, and set the interval from that. Running the next session while pigment is still present can stack pigment on pigment, so in that case we lengthen the interval and clear the pigment side first.

A combination works better than pinhole alone

Real scars rarely have just one property. Within a single scar there are depressed and raised parts together, and red and brown tones overlapping. So rather than repeating pinhole alone, combining several treatments according to how the scar presents often gives a better result. The axes placed together in a scar plan at ABLE Dermatology are as follows.

• Fractional CO2 — evens out texture and surface irregularity over a wide area. The axis most often used alongside pinhole.
• Subcision (Trifill) — where the floor of a scar is stuck to the tissue beneath and pulled in, this releases the tethering first. What pinhole divides is the fibrosis inside the scar, and what subcision divides is the tethering band beneath it, so the layer addressed differs.
• Potenza (microneedle RF) — delivers heat to the dermis through needles, placed where the deep layer needs addressing with relatively less surface damage.
• V-Beam — the axis for when redness remains in a scar. With red scars, addressing the color first can change overall visibility considerably.
• PicoPlus and Spectra — placed where brown pigment accompanies the scar, or where pigment has remained after a procedure.
• Rejuran Healer (PN) and Juvelook — the place for adding regeneration signal and volume on top of the healing process the laser has set up. Timed separately so as not to overlap treatments that need downtime.
• Botulinum toxin — as said above, sometimes used alongside to reduce the tension on a scar at sites with a lot of movement.

What matters here is not how many items there are but the order and the intervals. Put treatments that need downtime back to back and the skin has no time to recover; space different axes too far apart and the overall schedule simply lengthens. This is why a map of the whole course of sessions is drawn before the first procedure.

We set expectations first

One of the things that decides the result in scar treatment is where expectations were set before starting. The pinhole technique has been in use for a long time, and it is not treatment that returns a scar to original skin. How much less noticeable it can be made is the actual goal, and that range varies with the type of scar, the site, its age and the tendencies of the skin, with individual variation. That is why in consultation we set out first how far this plan is aiming, and which parts are being left to a later stage.

How we do it at ABLE Dermatology

Pinhole is the name of a method, not of a device. How far it is realized does change with the device, though. The more evenly each shot fires, and the more finely energy and pulse width can be set to the values you want, the more precisely the intended depth can be reached while thermal damage around it is kept down.

ABLE Dermatology runs the U-Pulse CO2 fractional laser for scars and pores, and the N-Pulse CO2 laser for removing moles and skin lesions. The pinhole technique is carried out with the CO2 laser among these that allows beam quality and energy to be controlled, and we plan so that in one place the broad area can be handled with fractional and the hardened points with pinhole.

What we actually check in consultation

• Color — whether redness remains, whether brown pigment is present alongside, or whether it has already faded white. The axis to start with changes with the color.
• Height and surface — we distinguish whether it is raised, whether it is depressed, or whether the height is much the same and the texture alone differs. The third is the band where pinhole is most often used.
• Firmness — where it feels hard to the touch, and whether it moves together with the surrounding skin. The points pinhole fires at are decided by this palpation.
• Tension — whether the scar is pulled when you speak or make an expression. If it is a place that gets pulled, we adjust depth and density, or consider botulinum toxin alongside.
• Skin tendency — we ask whether pigment has lingered after previous procedures or wounds. For skin where pigment lingers readily, we design from the outset with lower density and more sessions.

Device, parameters, sessions and intervals are set after these five have been checked. It is not an order in which the device is decided first and the scar fitted to it. Scar treatment is not yet as complete as we would like, but the range that can be addressed has widened steadily. It would be good to start by checking together which band your scar sits in.

From consultation to procedure

A board-certified dermatologist examines you directly, confirms the layer the cause sits in, decides the device and the parameters, and the same dermatologist carries on to perform the procedure. This is not a structure in which a consultant recommends the treatment.

Sessions, intervals, maintenance timing and cost are agreed together before the first procedure.