England and Wasps second row Joe Launchbury is out of the Six Nations as he requires surgery on a troublesome neck injury.
Launchbury first suffered the injury in November, and he will now miss three to four months of a crucial period as England build up to next year's Rugby World Cup.
Wasps director of rugby Dai Young told the official website: "We have consulted specialists and they have recommended surgery as the best option for him."
The neck injury kept Launchbury out of the recent Autumn Internationals, but before that he was a regular in Stuart Lancaster's side and has accumulated 22 caps so far.
England play Wales in their first Six Nations game in February.
