# “Bonnet bypass” using a radial artery interposition graft—how I do it

## TL;DR

A new surgical technique called the 'Bonnet bypass' is described to restore blood flow in cases where a standard bypass is not possible.

## Contribution

The novel use of a radial artery interposition graft in a 'Bonnet bypass' for revascularization when the superficial temporal artery is unavailable.

## Key findings

- The 'Bonnet bypass' uses a radial artery graft from the contralateral superficial temporal artery to the middle cerebral artery.
- A skullcap groove is drilled to position the graft and prevent mobilization or compression.
- This technique is suitable when the ipsilateral superficial temporal artery cannot be used as a donor vessel.

## Abstract

Common carotid artery (CCA) occlusion frequently results in compromised hemodynamics of the ipsilateral hemisphere with risk of infarction but also a lack of blood flow in the ipsilateral superficial temporal artery (STA), requiring a more complex revascularization strategy than a standard extracranial-intracranial (EC-IC) bypass when indicated.

We describe the performance of a “Bonnet bypass” using a radial artery interposition graft (RAIG) from the contralateral STA to the ipsilateral middle cerebral artery (MCA). A groove is drilled in the skullcap to position the RAIG and reduce risk of mobilization and compression.

The “Bonnet bypass” enables a revascularization procedure when the ipsilateral STA is not available as donor vessel.

The online version contains supplementary material available at 10.1007/s00701-025-06700-7.