Nicotine before Mohs: a cessation calendar keyed to your repair

The scheduling call is short. Someone confirms the date, tells you to bring a book because it will take most of the day, mentions blood thinners, and says that if you smoke you should stop beforehand. Then they hang up, and you are left with a piece of advice with no number attached to it. Stop when. Stop for how long. Stop or it will do what.

There is a reason the advice arrives vague. On the day it is given, nobody yet knows how the wound will be closed, and the closure is what decides whether nicotine matters a little or a great deal.

The original element in this piece is a cessation calendar keyed to reconstruction type, which sorts Mohs repairs into three tiers by how much they depend on borrowed blood supply, attaches a different timing target to each tier, and states plainly which tier your defect is likely to land in based on where the tumor is. The vascular biology is established and the outcome data for Mohs reconstruction specifically exists. What does not exist is the version that tells a patient which tier applies to them before the surgery is booked, which is the only point at which the advice can still be acted on.

Why closure type is the variable. A wound that is simply sewn together side to side keeps its own blood supply. The skin either side of the line is attached to everything it was attached to yesterday. Healing is a matter of the edges knitting, and while nicotine does not help, the tissue is not being asked to survive on a reduced supply.

A flap is different. A flap is skin that has been partially detached, moved, and sewn into a new position, and it stays alive on the blood that reaches it through the base it is still connected to. That base is narrower than the tissue it feeds. The flap is therefore living on a margin, and anything that narrows the vessels feeding it eats directly into that margin.

A graft is more precarious still. A skin graft is completely detached tissue laid onto a wound bed, with no blood supply of its own at all for the first days, surviving on diffusion until new vessels grow in from underneath. If those vessels are slow to arrive or arrive constricted, the graft dies.

Nicotine is a vasoconstrictor. Carbon monoxide from combustion reduces the oxygen carrying capacity of the blood that does arrive. Smoking also impairs the cellular machinery of wound healing more broadly. Put those together and the effect scales precisely with how much the repair depends on marginal perfusion. A study looking specifically at Mohs reconstruction with flaps or grafts found smoking associated with worse outcomes in exactly this population (JAMA Facial Plast Surg 2019).

The three tiers. Tier one is a defect likely to close primarily, in a straight line, or to be left to heal on its own by second intention. Small lesions on skin with laxity, on the trunk, on the cheek in an older patient with mobile skin, and many defects on the scalp fall here. The cessation benefit is real but modest, and the honest framing is that quitting helps healing generally rather than preventing a specific catastrophe.

Tier two is a defect likely to need a local flap. This is the large middle of Mohs reconstruction: the nose, the ala, the lower eyelid area, the ear, the upper lip, anywhere the skin has nowhere to go and tissue has to be recruited from a neighbour. A meaningful proportion of facial Mohs defects land here, and this is the tier where the cessation conversation deserves a date rather than a suggestion.

Tier three is a defect likely to need a skin graft, or a staged repair with an interpolated flap left attached for weeks. Larger nasal defects, defects on the nose where local tissue is exhausted, and defects too big for a flap fall here. This is where the failure mode is not a slightly worse scar but tissue that necroses and has to be redone.

The timing that goes with each tier. The conventional surgical target is to stop several weeks before an operation and to stay stopped through the healing period, and the reason for a period of weeks rather than days is that the different effects reverse on different clocks. Carbon monoxide clears in a day. Nicotine clears in a day or two. The impairment of the healing response itself takes longer to normalise. The commonly used figure in surgical practice is around four weeks before and four weeks after, and it comes from the general surgical evidence on preoperative cessation, where interventions started roughly four to eight weeks ahead produced the clearest reduction in wound complications (Cochrane 2014). That figure is best treated as the target for tiers two and three.

The part almost nobody says out loud is what to do when there is not four weeks, which is most of the time, because Mohs is often scheduled inside a month. The answer is that the interval is a gradient rather than a threshold. Stopping ten days out is better than stopping the night before, and stopping the night before is better than nothing, because at least the vasoconstriction and the carbon monoxide are gone on the day. What is genuinely not optional in tiers two and three is the period after surgery, and that is the one patients most often ignore.

The nicotine replacement trap. Patches, gum, lozenges and pouches remove the combustion products but keep the vasoconstrictor. For a tier one repair that trade is probably a net gain. For a graft, replacing cigarettes with a patch is not the same as stopping, because the vessel constriction is the thing that was going to kill the graft. That distinction is rarely spelled out, and it is worth raising directly with the surgeon rather than assuming either answer.

What the studies do not tell you. There is no randomized trial of cessation timing in Mohs reconstruction. Nobody has taken smokers facing nasal flaps, assigned them to stop at four weeks, two weeks and one week, and counted necrosis. What exists is observational outcome data in this population, a large general surgical literature on smoking and wound complications, and the vascular pharmacology. The four week figure is imported from that broader surgical practice, not derived from Mohs, and it should be described that way.

How to find out your tier before the day. Ask the question at the biopsy visit or the booking call, in this form: given where this tumor is and how big it looks, is the repair more likely to be a straight line closure, a flap, or a graft. Nobody can promise, because the defect is not known until the tumor is out, and that uncertainty is inherent to how the operation works and why Mohs takes all day. But a surgeon can tell you which is likely, and likely is enough to choose a cessation date. It is the same conversation as the one about anticoagulants, where the answer also turns on the specifics rather than a blanket rule, covered in what to hold and what never to stop.

If the answer is flap or graft, you now have a reason with a mechanism attached, which is a different thing from being told to stop smoking. It is worth pairing with a realistic look at what the repair options actually involve, because the tier that demands the most of your circulation is also the tier with the most to lose.