Gluing the vein shut works as well as burning it. The difference is in what each one leaves behind

Thermal ablation closes a vein by heating it, which works and requires anaesthetic fluid injected along the whole length of the vein to protect the surrounding tissue from the heat. Cyanoacrylate closure removes the heat and the fluid by gluing the vein shut instead. The trade that makes is now measurable at scale.

What the pooled evidence shows#

A systematic review and meta-analysis published in the Journal of Vascular Surgery: Venous and Lymphatic Disorders pooled 21 studies — randomised trials, cohort studies and case-control studies — covering 7,844 patients and 9,677 limbs treated for great saphenous vein incompetence.

On the two outcomes that decide whether a treatment worked — did the vein close, and did the clinical severity score improve — the techniques are equivalent. The differences are in the aftermath: less bruising, less numbness, and a shorter procedure.

Those advantages follow directly from what cyanoacrylate does not do. Bruising largely comes from the tumescent anaesthesia, a large volume of dilute local anaesthetic infiltrated along the vein; numbness comes from heat or needles near the nerves that run beside it. Remove the heat and the infiltration and both fall. This is a mechanistically coherent result rather than a statistical curiosity.

What a meta-analysis of this size cannot see#

A pooled analysis of 7,844 patients is well powered for events occurring in a few percent of cases and badly powered for events occurring in a few per ten thousand. The finding of no significant difference in deep vein thrombosis is a real and useful result about common complications. It is not a statement that the procedure carries no thrombotic risk.

The case literature carries what the pooled data cannot. A report in Annals of Vascular Diseases describes an 81-year-old woman who underwent cyanoacrylate closure with stab avulsion under general anaesthesia for bilateral small saphenous varicosities. Fourteen days later she developed severe dyspnoea, was diagnosed with pulmonary embolism and deep vein thrombosis, and died 24 days after admission despite anticoagulation, cardiopulmonary support and catheter-directed thrombectomy.

The difference that no outcome measure captures#

Thermal ablation destroys a vein and the body absorbs what is left. Cyanoacrylate leaves a polymer inside the leg permanently. That is not a complication — it is how the treatment works — and it is the one respect in which the two techniques are not different versions of the same thing.

The case literature reflects it. A 74-year-old woman had an uneventful recovery from cyanoacrylate closure until the day after she started dupilumab, an immune-modulating drug, when she developed fever and painful inguinal nodules; the granulomatous lesions progressed despite corticosteroids and antihistamines and required repeated bilateral excisions over three months. A separate report describes surgical excision of a glue-filled vein for a delayed-type hypersensitivity reaction. These are rare, they are reported as individual cases, and they have no counterpart after thermal ablation because there is nothing left to react to.

The occlusion and severity-score equivalence in the meta-analysis covers early and mid-term outcomes. What a permanent implant does over twenty or thirty years in a leg is not a question the current evidence has had time to ask.

What this supports in practice#

For closing an incompetent great saphenous vein, cyanoacrylate and radiofrequency ablation work about equally well on the evidence available. Cyanoacrylate offers a faster procedure without tumescent anaesthesia, less bruising and less numbness, which are genuine benefits to a patient rather than technical conveniences.

What it does not offer is a longer or better-studied safety record, and it introduces a class of reaction that heat-based treatment cannot produce. A patient choosing between them is choosing between a less uncomfortable recovery and a longer track record — which is a reasonable thing to be told, and rarely is.