Protocol for an international, multicentre audit of
outcomes following appendicectomy
The Multicentre Appendicectomy Audit Group, on behalf of the National Surgical
Research Collaborative
Local collaborative contacts:
West Midlands Research Collaborative: cazrichardson@doctors.org.uk
London Surgical Research Group: lsrgcommittee@googlegroups.com
Welsh Barber Surgeons Research Group: julie.cornish@gmail.com
East of England Surgical Research Group: sipilgrim@hotmail.com
Mersey Research Group for General Surgery: mergs@liverpool.ac.uk
South Peninsula Audit and Research Collaborative for Surgeons:
sparcsexec@gmail.com
Yorkshire Surgical Research Collaborative: danberal@hotmail.com
Trent Surgical Research Collaborative: ashbhalla@doctors.org.uk
Other regions: aneelbhangu@nhs.net
For protocol issues:
Protocol management group: Aneel Bhangu, Caroline Richardson, Andrew Torrance,
Nick Battersby, James Royle, Paul Marriott, Dmitri Nepogodiev, Lisa Whisker, David
Bartlett, Kaori Futaba, Thomas Pinkney.
Protocol support: Aneel Bhangu, aneelbhangu@nhs.net
Database support: Andrew Torrance, adwtorrance@doctors.org.uk
Data handling: aneelbhangu@nhs.net
Short title: multicentre appendicectomy audit
Conflicts of interest: none
Acknowledgements: with thanks to the Committee of the West Midlands Research
Collaborative, the Academic Department of Surgery at the University of Birmingham,
Professor Derek Alderson and Professor Dion Morton
Abstract
Background: Appendicectomy is the most common general surgical emergency
operation. Management and subsequent outcomes remain controversial, with
varying rates of negative appendicectomy, wound infections, post-operative
abscesses and lengths of stay. A high quality audit from a multi-centre, non-trial
setting will establish current practices, outcomes and complication rates.
Aim: To describe outcomes of appendicectomy from an international, multi-centre,
audit setting.
Endpoints:
Several outcomes
measures
are
used
to
assess quality of
appendicectomy. No suitable single marker exists. The primary outcome measure to
be determined by this audit is negative (normal) appendicectomy rate. Secondary
measures are: (1) rates of wound infections needing readmission; (2) intraabdominal abscess rate; (3) provision of laparoscopic appendicectomy.
Methods: The audit will be performed over a two-month period, following a twoweek, five centre pilot. Participation from 30 centres is estimated to recruit
approximately 1000 patients. The audit will be performed using a standardised predetermined protocol and a database. The audit standard will be the established rates
from the Western literature, including: rate of negative appendicectomy <20%;
wound infection <10%; intra-abdominal abscess <2.5%. The level of use of
laparoscopic surgery will be measured. The report of this audit will be prepared in
accordance to guidelines set by the STROBE (strengthening the reporting of
observational studies in epidemiology) statement for observational studies.
Discussion: This multicentre, international audit will be delivered by trainee led
collaborative research networks to ensure high volume without compromising quality.
Introduction
Appendicectomy for acute appendicitis is the most commonly performed emergency
general surgical procedure. In England, approximately 46,000 appendicectomies are
performed annually1. The open approach has remained largely unchanged since the
19th century2, until the introduction of laparoscopic surgery in 19833. Over 50
randomised trials have compared the two approaches, producing conflicting and
variable results in terms of infection rates, pathological findings and lengths of stay4.
Several controversies remain surrounding the management of appendicitis and
subsequent outcomes. Diagnosis remains difficult, with negative rates of up to 30%
in females and 20% in males5-7. There is little data on surgical complications
following negative appendicectomy. The introduction of modern imaging strategies,
such as computed tomography, have not widely improved diagnostic yield over
clinical examination augmented with serum inflammatory markers outside trial
settings8. Post-operative infections remain particularly problematic, with superficial
wound infection rates of up to 10% and intra-abdominal abscess rates of up to 5%4 910.
Additional variation is provided by the use of laparoscopic versus open
appendicectomy, where laparoscopy may reduce wound infections but sometimes at
the cost of increased intra-abdominal infections4 6. Its widespread uptake has been
limited, despite recommendations for its routine use 4 11. There is little consensus on
the use of peri-operative antibiotics to prevent wound and intra-abdominal infectious
complications.
Reports of outcomes from appendicectomy generated from randomised controlled
trials or large national database analyses (using administrative data) may not reflect
wider practice4 6. This may be due to non-generalisability of some randomised trials,
for reasons including their single centre nature, patient selection bias and seasonal
variation4 12-15.
The primary aim of this audit is to describe outcomes following appendicectomy from
an international, multi-centre audit of contemporary practice. By using negative
appendicectomy rates as a primary outcome, comparisons can be made between a
range of contexts to reflect practice within the National Health Service (NHS). These
include urban and rural locations, low and high volume hospitals, trainee and
consultant operating, paediatric and adult practice.
Methods
Endpoints
Several outcomes measures are used to assess quality of appendicectomy, since no
single marker exists. The primary outcome measure to be determined by this audit
is negative (normal) appendicectomy rate. Secondary measures are: (1) rates of
wound infections needing readmission; (2) intra-abdominal abscess rate; (3)
provision of laparoscopic appendicectomy.
Audit standard
The current standard for rates of the outcome measures are those established by the
existing published literature and guidelines relating to appendicectomy. These will
be taken as:
(1) Overall negative appendicectomy rate of <20%; 5 to 15% in males and 10 to
30% in females5-7.
(2) Wound infection rate of <10%. The highest level of evidence arises from a
Cochrane review which pooled data from 50 randomised trials to find an
overall wound infection rate of 5.4% (321/5972)4. The inter-quartile range for
rates from individual studies was 2.5% to 7.6%.
(3) Intra-abdominal abscess rate of <2.5%. The highest level of evidence arises
from a Cochrane review which pooled data from 45 randomised trials to find
an overall intra-abdominal abscess rate of 1.4% (78/5577)4. The inter-quartile
range for rates from individual studies was 0% to 2.3%.
(4) Routine use of laparoscopy. Guidelines from the Society of American
Gastrointestinal and Endoscopic Surgeons (SAGES) recommend routine use
of laparoscopy unless contra-indicated11. The impact of laparoscopy on the
main outcome measures will be assessed. The highest level of evidence
arises from a Cochrane review of 57 randomised trials, which showed that LA
was associated with fewer wound infection (OR 0.43; CI 0.34 to 0.54), more
intra-abdominal abscesses (OR 1.87; CI 1.19 to 2.93) and a marginal increase
in duration of surgery (10 minutes [CI 6 to 15])4.
Eligible centres
Any hospital which provides acute general surgical services is eligible to enter
patients. A named consultant will act as the principal investigator and data collection
will be completed by a doctor working at that hospital. This audit of current practice
must be registered with each individual hospital’s clinical audit department.
Patient eligibility
All patients in whom appendicectomy for suspected acute appendicitis is performed
can be entered into this audit (figure 1). Patients whose final pathology reveals a
diagnosis other than appendicitis or a normal appendix will be analysed separately
(e.g. cancer, Crohn’s disease). No upper or lower age limits will be set.
Projected numbers
The pilot was conducted in 5 centres in the West Midlands region (Good Hope
Hospital, Royal Shrewsbury Hospital, University Hospital of North Staffordshire,
Warwick Hospital and the Worcester Royal Infirmary).
Eight surgical research collaboratives have expressed an interest in participating in
this national audit (table 1). Based on appendicectomy specific Hospital Episode
Statistics data from a range of centres across the collaboratives, approximate
accrual rates were estimated (table 2). Recruitment from 30 centres over two months
with an average of 4 patients per week will return 992 patients, or 893 if 10% of
patients are not recruited or lost to follow-up. We anticipate being able to identify
1000 patients.
Audit phases

Pilot: a two-week pilot across five hospitals in the West Midlands was
performed to test the data collection tool. Adjustments based on these
experiences were made before delivering the audit nationally.

Main audit: the main audit will then be performed across eligible centres
between 1st May and 30th June 2012, with the final patient reaching 30-day
follow-up on 30th July. A minimum of 10 centres is expected with no
maximum. A guide has been produced for local investigators wishing to open
their centre to this audit (appendix 1).
Data collection

Outcome variables: The outcomes variables to be measured are shown in
appendix 2.

Data collection: Data will be collected on each eligible patient using a
standardised electronic proforma which will be held securely on an NHS
computer at each site.

Data collection points:
o Patient identification: Patients should be identified on a daily basis by
on-call teams, at handovers, from on-call lists and from emergency
theatre logbooks.
o Pre-operative data: A trainee will fill this in before the operation.
o Operative data: This should be completed either by or with the
operating surgeon at the end of the procedure.
o Post-operative data: All patients will be followed for 30 days following
their operation. The hospital’s electronic records should be checked by
a trainee to identify any re-admissions or re-attendances to either the
hospital’s Emergency Department, surgical assessment unit or wards.

Data collation: Patient anonymised data will be collated centrally on a secure
computer within a National Health Service (NHS) hospital. Data will be
transferred by the secured NHS.net email service.

Hospital related variables: separate variables will be collected through an
online questionnaire relating to each hospital’s local policies, including the use
of laparoscopic appendicectomy (table 3). This will be distributed mid-audit.
Definitions
The following definitions will be used for this study:

Open appendicectomy – appendicectomy performed through any abdominal
incision

Laparoscopic appendicectomy – appendicectomy performed entirely
laparoscopically without any additional abdominal incision

Laparoscopic converted to open – laparoscopic approach converted to an
open incision operation, or in which an abdominal incision to assist the
procedure was needed.

Normal appendicectomy (clinical) – surgeon’s intra-operative judgment that
no inflammation was present.

Normal appendicectomy (pathological) – absence of inflammation on
pathological examination.

Simple appendicitis – inflammation of the appendix without perforation, pus
or abscess.

Gangrenous appendicitis – the presence of gangrene without perforation.

Perforated appendicitis – the presence of perforation with or without
gangrene. If perforation and gangrene exist together, perforation should be
recorded.

Post-operative length of stay – this will be calculated electronically from
date of surgery to date of discharge.

30-day post-operative complications – complications occurring within 30
days from the date of surgery.

Wound infection – any one of:
(1) Purulent drainage from the incision
(2) At least two of: pain or tenderness; localised swelling; redness; heat; fever;
AND The incision is opened deliberately to manage infection or the
clinician diagnoses a surgical site infection
(3) Wound organisms AND pus cells from aspirate/ swab

Intra-abdominal abscess/collection – (1) A clinical diagnosis of wound
infection with dehiscence of mass closure or any layer below scarpa’s fascia;
(2) A clinical diagnosis of intra-abdominal collection (fever or abdominal pain)
with operative or radiological evidence of a collection.
Statistical analysis
The report of this audit will be prepared in accordance to guidelines set by the
STROBE (Strengthening the Reporting of Observational Studies in Epidemiology)
statement for observational studies16. Data will be tested for distribution and
differences between groups compared using unpaired t-tests, Mann-Whitney U tests
and Chi squared tests as appropriate.
To account for the impact of predictive variables when assessing outcomes,
multivariable regression models will be built to produce odds ratios (OR). The OR
represents the odds of an adverse event (e.g. wound infection) occurring in the
experimental group (laparoscopic appendicectomy) versus the control group (open
appendicectomy) and approximates the relative risk. Univariable modelling will test
each predictor’s influence on the desired outcome. A multivariable model will then be
build using forward stepwise conditional processing. Variables entering into the
model will includes those which were significant at a level of p<0.1 at univariable
level, and will also include variables which were not statistically significant but are
deemed to be clinically relevant. An OR of greater than one indicated greater risk of
an adverse event happening in the experimental group. The point estimate of the OR
was considered to be statistically significant at the P<0.05 level if the 95 percent
confidence interval (CI) did not include the value one. Funnel plots will be used to
test the performance of individual (anonymised) centres for negative rates.
Table 1: Trainee led research collaboratives that have indicated an interest in
participating in the audit
Collaborative
East of England Surgical Research Group
London Surgical Research Group
Mersey Research Group for General Surgery
South Peninsula Audit and Research Collaborative for Surgeons
Trent Surgical Research Collaborative
Welsh Barber Surgeons Research Group
West Midlands Research Collaborative
Yorkshire Surgical Research Collaborative
International centres identified: Japan, Hong Kong, New Zealand, USA
Table 2: Estimated accrual rates based on Hospital Episode Statistics data from
selected centres across participating regions.
Number of hospital
Trusts
Pilot
Average number Total
Corrected*
per week
5
56
50
10
4.5
363
300
20
4.2
673
606
30
4.1
992
893
*taking into account 10% of patients being lost to follow-up.
Table 3: Plan for electronic unit specific questionnaire to be distributed mid-audit
Provision of emergency surgical services
Is your centre a:
How many consultants are on the general surgery
on-call rota?
How many general surgical beds are in your
hospital?
Does your centre serve a predominately rural or
urban population?
During weekdays (0800-1800) does your centre
Out of hours (weekdays 1800-0800 and weekends)
does your centre
For evenings (1600-0000) does your centre
During weekends, it is possible to get an ultrasound
scan
Out of hours, it is possible to get an CT scan
Appendicectomy policies
How many consultant surgeons offer laparoscopic
appendicectomy?
Is laparoscopic appendicectomy available at your
centre?
During working hours (0800-1800, weekdays), is
laparoscopic appendicectomy:
During weekend days (0800-1800), is laparoscopic
appendicectomy:
Out of hours weekdays (1800-0800), is
laparoscopic appendicectomy:
At your centre is there a protocol to give antibiotics
At your centre is there a protocol to routinely send
pus swabs
At your centre is there a protocol to excise the
appendix during laparoscopy if it appears grossly
normal?
University hospital/ tertiary centre;
District general hospital;
Paediatric centre
Urban;
Rural
Provide emergency surgical services and there is a
dedicated emergency theatre;
Provide emergency surgical services but there is no
dedicated emergency theatre;
Provide emergency surgical services and there is a
dedicated emergency theatre;
Provide emergency surgical services but there is no
dedicated emergency theatre;
Routinely perform emergency surgery;
Only perform emergency surgery that cannot be
delayed until the day
Same Day; Not available until Monday
Saturday; Sunday;
Immediately;
Within 4 hours;
Not available until the next day
Not available until the next working day
Yes/ No
Mandatory unless contra-indicated;
Available if requested by consultant;
Available if requested by trainee;
Not available
Mandatory unless contra-indicated;
Available if requested by consultant;
Available if requested by trainee;
Not available
Mandatory unless contra-indicated;
Available if requested by consultant;
Available if requested by trainee;
Not available
Pre-operatively;
At induction;
Intra-operatively;
Post-operatively
No protocol
Protocol to send; protocol not to send; no protocol
Protocol to remove; protocol to NOT remove; no
protocol
Figure 1: Patient inclusion pathway
Diagnosis: suspected acute
appendicitis (on or during acute
admission)
Exclude:
 Non-operative management
Theatre
Exclude:
 Appendicectomy not performed
INCLUDE: Appendicectomy
performed
Appendix 1: Guide to National Audit for Regional Research
Collaboratives
1. Disseminate the idea to the members of the collaborative.
2. Identify 2 collaborative members who will act as lead and will have the
responsibility of liaising with the other regional collaboratives.
3. Identify one member from each collaborative to be involved in the writing team
at a national level.
At Trust level:
1. Identify a PI (Primary Investigator) at each trust – this is a Consultant who
agrees to support the audit.
2. Present the idea to the surgical directorate, either at a local audit meeting or
through the clinical audit lead, to ensure permission is gained for the inclusion
of all eligible patients in the audit.
3. Register the project with the audit department, ensuring that they are aware
that this is part of a national project. For data protection issues, it is important
to emphasise that only anonymised data will be sent via the nhs.net email
system to a nominated email address from the senior management team.
Ensure that local Trust and Caldicott guidelines are followed for the protection
of data at a local and national level.
4. Aim to engage other trainees who can help with data collection.
5. Speak to ward clerks to ask that notes for patients undergoing
appendicectomy are kept on the ward until all relevant data has been
collected e.g. on Monday morning for weekend operations.
6. Identify who will be responsible for collating 30-day follow-up data, where this
information will be obtained from and how they will do it.
Appendix 2: see separate sheet
Appendix 3: projected timeline
1. Monday 19th March – disseminate protocol to collaboratives
2. Monday 1st May – first day of patient inclusion
3. Friday 29th June – date of last patient inclusion
4. Monday 30th July – last 30-day follow-up (end of data collection)
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