What are Surgical Site Infections?

Surgical Site Infections (SSI) are procedure-specific infections caused by micro-organisms getting into a part of the body that has been operated on and multiply in the tissues. They develop because these areas are more vulnerable to infection following surgery or because of poor infection control processes.

In line with guidance from the UK Health Security Agency (UKSHA), reporting these infections is currently only mandatory for hip and knee replacement surgery. It is optional for other types of surgery.

Currently PHIN only publishes counts of SSIs over a recent 12-month period in conjunction with Hip and Knee Replacement surgery.

What information about Surgical Site Infections does PHIN publish?

We publish SSI information for hospitals on Excel datasheets in the Our Data section of the PHIN website in the following ways:

• SSIs by Procedure
• SSIs by Site

To view SSIs by Procedure go to the Infections datasheets and select the latest data (or the archived data for the period you are interested in). This will download the Excel spreadsheet.

You then need to select the tab SSI by Procedure.

Once you have done that, you’ll be able to see the procedures being reported on, the number of infections reported, the number of discharges (when people are released from hospital) and the percent of those discharges who suffered an infection. For example you would be able to see that if 46 SSIs were reported for hip replacement surgery, but that was a very small percentage of the overall number of this type of surgery, the SSI rate would only be 0.1%. Therefore, it is highly unlikely that anyone having a hip replacement procedure will suffer an infection. 

To view the SSIs by Site, choose the next tab along in the same spreadsheet. 

You will then be able to see the hospital as well as whether it is an independent (IND) or NHS Private Patient Unit (NHS PPU), the procedure conducted, the number of months we’d expect the hospital to have reported on, and number of infections and percentage of infections.

Why should I be interested in this information?

It can be informative to know how many infections a hospital’s patients experienced in a year. However, comparing counts for different hospitals is not straightforward. Some hospitals are bigger, treat more patients and therefore are more likely to experience more SSIs. Therefore, when such hospitals are compared with smaller hospitals, while they might have recorded a greater number of infections their rate of infection may be greater, the same or less.

One hospital may also have a higher rate of infections compared to another because it treats more frail, elderly or seriously ill patients. PHIN’s method is currently unable to take these factors into account and therefore this needs to be borne in mind when making comparisons.

A hospital that only performs minor procedures (such as eye surgery) might expect to have fewer infections. Whereas hospitals undertaking more complex treatments (such as major bowel surgery) might have more. But if the one providing complex care applies the appropriate levels of infection control, its count or rate of infections might well be the same as the one providing eye surgery.

Because of these and other factors, these infection measures alone, published on PHIN’s website and elsewhere, can’t tell you the full story of an individual patient’s risk of getting an SSI at a particular hospital. Therefore, this information is best used as part of the wider discussions about patient safety and care with your consultant or hospital.

Help with understanding and using our healthcare datasheets

Find out more about our data sheets, including how we protect patient data.

Go to Datasheets.