Sclerotherapy: the treating doctor and the blinded raters gave different answers

A 2015 trial at the University Hospital of Bern, Switzerland. Prospective, randomised, open-label.

Its introduction says as much: there are no blinded randomised controlled trials comparing laser modalities with the gold standard, sclerotherapy, and the few available studies have small cohorts. This trial set out to fill that gap.

56 women with primary leg telangiectasias and reticular veins took part. The design is good: the two legs of one person were split.

• one leg — multiple synchronised long-pulsed Nd:YAG laser
• the other leg — foam sclerotherapy with polidocanol 0.5%

Two sessions six weeks apart, with assessment at six weeks and six months. There were two ways of assessing.

• the handling physician looked in clinic
• two investigators not involved in the treatment scored the photographs at the end, blinded, on a six-point scale from 1 (no change) to 6 (100% cleared)

The results. The two assessments diverged.

• the handling dermatologist — laser 30–40% improvement (median 3), sclerotherapy 50–70% improvement (median 4)
• the blinded investigators — median 5 for both, that is more than 70% cleared, with no difference between the groups (p = 0.84)
• improvement came more quickly with sclerotherapy. But at the last visit there was no difference.
• patient satisfaction was very good with both and similar between them.
• pain differed — the laser was significantly more painful (p = 0.003).

Now how to read it.

First, this is why this site pegs its badges to blinded assessment. It is not about deciding which of the two numbers is right. The person who did the treatment knows what they did. A score given in that state cannot separate the effect from the expectation. A blinded rater does not have that information.

And look at the direction. The treating doctor saw sclerotherapy as better. The blinded raters saw no difference. It is the same kind of divergence you have seen on the PRP, mesotherapy and GHK-Cu pages.

Second, there is no untreated control. Both legs were treated. So the trial did not measure whether sclerotherapy beats doing nothing. It compared two procedures with each other.

Third, it is open-label. The treatment itself cannot be masked — you know when a needle or a laser has been on you. So only the photographic assessment was blinded. That is a common limit in this layer, and here it was covered with photographs.

Fourth, 56 people, one trial, six months. Leg telangiectasias are something that keeps appearing, and six months is short for seeing that.

Fifth, the authors' conclusion separates the two rather than ranking them. They write that the laser suits needle phobia, allergy to sclerosants, and very small veins with telangiectatic matting, while sclerotherapy can also treat the feeder veins. Not a conclusion that one won.

So it sits at 'moderate'. A good design — own control with blinded photographic scoring — but one trial and no untreated arm.

A 2004 trial. Single-blind, randomised, comparative, and it shows what else changes when the agent changes.

150 patients were randomised and 147 could be evaluated. Comparable areas were chosen on one person — the lateral face of the thigh. Photographic assessment was by two independent blinded experts, and the paper records that internal and external agreement was good.

Three things were compared.

• pure chromated glycerin (CG)
• polidocanol 0.25% solution
• polidocanol 0.25% foam

The results. The three came apart.

• clearing of vessels — chromated glycerin was significantly better than polidocanol solution or foam (p < 0.002)
• patient satisfaction was also higher with chromated glycerin. But it did not reach statistical significance.
• pain — chromated glycerin was significantly more painful at the injection sites.
• side effects — more with foam. Microthrombi and telangiectatic matting.
• three patients treated with polidocanol foam had a transient visual disturbance.

How to read it.

First, 'sclerotherapy' is not one thing. Which agent, at what concentration, as a liquid or as a foam moved the result, the pain and the side effects at the same time. So 'I had sclerotherapy' does not say what was had. Ask what is going in.

Second, the one that cleared best hurt most. That was chromated glycerin. This site does not hide that kind of trade-off. Which to choose is not settled by the result alone.

Third, the difference in satisfaction was not significant. On clearing of vessels the three clearly separated, but on patient satisfaction it did not reach statistical significance. Another instance of what is measured and what is felt not always moving together.

Fourth, three transient visual disturbances is not a figure to pass over. It is a phenomenon reported with foam sclerotherapy, and in this trial it came only from the foam arm. What the 2015 trial above used was also polidocanol foam. It appears again under risks below.

Fifth, the abstract does not state the observation period. So the duration field on the badge above is empty. We will not invent it.

Sixth, this trial is from 2004. And the agents and concentrations used here cannot be assumed to be what is used everywhere now.

So it sits at 'moderate'. Good conditions — 150 people with blinded photographic assessment — but no untreated arm and one trial.