30 Day Elective Procedural Mortality

What this data shows:

Standardised surgical mortality rates (SMRs) are internationally recognised as a broad indicator of the quality surgical care. 30 day elective (planned) procedural mortality is one of a number of quality assurance measures that is routinely used in the assessment of surgical outcome.

How the data is gathered:

Neurosurgeons undertake a wide range of planned operations that include simple procedures lasting less than one hour, where the risk of death is close to zero, and complex procedures lasting more than twelve hours, where the risk of death may be over 10% (1 in 10). Thus the risk of death from a planned neurosurgical operation may differ by more than a 100-fold.

There is no typical operation undertaken by all neurosurgeons in sufficient numbers that it may be used as a sole indicator of outcome. By reporting the outcome of all planned operations undertaken by neurosurgeons, this audit provides an overview of planned neurosurgical activity in England.

The risk of surgery depends not only on the operation but also on the age and medical condition of the patient. It is now common for patients over the age of 70 to undergo major neurosurgical procedures when the benefits to the patient outweigh the increased risks.

The outcome of modern operations does not depend solely on the skill or judgment of individual surgeons. In many of the operations assessed in this audit neurosurgeons have operated jointly in teams with surgeons from other specialties and occasionally the procedure has been undertaken by other specialists.

When the data is shown:

It is normal for different clinicians and units to have different results and there is an expected range results can fall in. Sometimes results may fall outside the expected range, which could be an indication that the care provided is either significantly poorer or significantly better than expected. But sometimes these results just happen by chance. Detecting whether a result falls outside the expected range by change or because of a significant reason can be challenging. We want to reduce the times when we identify a unit or individuals results as being outside of the expected range just because of chance.

We can do this by using a wide definition of the expected range. The narrower the definition of the expected range the greater the chance of a result being labelled as outside of it just because of chance.

Audits participating in publication on NHS.uk and MyNHS are asked to use statistical analysis to do this.

In order to adjust for the inherent risk of an operation and the condition of the patient, statistical methods may be used to calculate a standardised mortality rate (SMR). The SMR reported in this audit has been developed specifically to reflect the clinical practice of neurosurgeons.

However, these statistical methods cannot fully account for variations in the sort of patients that some neurosurgeons treat. Neurosurgeons who, for example, routinely operate on patients with malignant tumours involving the brain and spine or complex disorders of blood vessels will have higher SMRs. Neurosurgeons who undertake low risk spinal procedures on high risk elderly patients may appear to have higher SMRs. This audit confirms that the average risk of death from a planned neurosurgical operation is less than 0.5%. With such small numbers of deaths, the elective mortality rate of an individual surgeon is heavily dependent on chance variation.

This audit considers patients who have undergone an elective operation. The classification of an operation as elective (planned) or non-elective (emergency or urgent) depends on the procedures adopted by each neurosurgical unit. Some units may see patients requiring urgent surgery in an assessment clinic before admission. Under NHS information rules these patients are considered as elective cases. This will add to the risk level of patients under the care of patients undergoing surgery at those hospitals.

More information about the data source:

HES data is dependent on the accuracy and completeness of clinical coding undertaken by the Trusts responsible for Neurosurgical Units in England. Trusts adopt different procedures to validate their coding before it is provided to the NHS. Working through the Neurosurgical National Audit Programme, consultant neurosurgeons have reviewed the coding of deaths to ensure that the data is as accurate as possible.

The data used in this outcome publication has been derived from three years’ of NHS England Hospital Episodes Statistics (HES). The HES data has been compared with data from the Office of National Statistics to determine those patients that died within 30 days of admission to hospital for the planned operation.

Data Source:

NHS England Hospital Episodes Statistics (HES) and the Office of National Statistics.

Data Period:

Annual 1st April 2013 – 31st March 2016

Data Supplier:

University Hospitals Birmingham Health Evaluation Department as contracted by the The Neurosurgical National Audit Programme

Further Information:

Further information is available on the NNAP website and via the NNAP Chair, Mr Richard Nelson – Richard.nelson@nbt.nhs.uk