The General Medical Council is in the process of introducing revalidation for all registered physicians, with an expected rollout sometime in 2011. It is likely that, for surgeons, part of this revalidation will entail tracking outcomes for surgery for each surgeon. In our trust, as well as many others, the responsibility for collecting this data has been given to the hospital. Different trusts are at different levels of infrastructure development to meet these upcoming revalidation needs. Therefore, some trusts may be able to readily give you this information, and some will not.
The Bristol report was pivotal with regards to signalling to trusts the need to track surgical outcomes per surgeon. Trusts therefore usually collect this information, but may not make it publicly available yet (I'm not an expert in the field of revalidation--most physicians aren't because it's new--but there is talk that information for GMC revalidation purposes will be treated as confidential), or it may be available to the public but hard to collate due to the infrastructure issues I mention above.
In short, contact the trust of interest. Or, contact the patient relations department of the hospital(s) of interest, and see what they tell you. Expect some raised eyebrows at your request. In some trusts, all surgeries for a particular speciality (ex. orthopaedics) may be based at one hospital within the trust, so they may not understand why you are asking at first.
If you're asking around in England and meet any resistance, remind the person you're talking to as to how the Royal College of Surgeons in England feel about the issue:
http://www.rcseng.ac.uk/media/media-background-briefings-and-statistics/measuring-surgical-outcomes?searchterm=measuring+