The Use of Wound Protectors to Prevent Surgical Site Infection for Whipples (Pancreatoduodenectomy) With Intrabiliary Stents: A Randomized Controlled Trial.
Background: There are no published studies regarding the use of wound protectors in the
context of surgical site infection (SSI) rates among patients receiving a
pancreatoduodenectomy (Whipple) with preoperatively placed intrabiliary stents. In high
volume experiences, the SSI rate is 40-50% within this cohort. In Calgary, preoperative
biliary stent placement for bile duct decompression represents the norm given typical
surgical wait times. In addition to having higher associated lengths of hospital stay, ICU
admissions, hospital re-admissions, and overall mortality, patients with SSI are also
delayed, and often omitted, in their progression to critical oncologic adjuvant
chemotherapy. As a result, SSI remain crucial and devastating complications for pancreas
surgeons and their patients alike.
Methods: The investigators will complete a randomized controlled trial evaluating the rate
of SSI in adult patients who undergo a pancreatoduodenectomy following biliary stent
placement when wound protectors are employed versus no wound protector use. This trial will
employ block randomization. All four University of Calgary Heapato-Pancreatico-Biliary (HPB)
surgeons will participate with a planned inclusion of all patients scheduled to undergo a
Analysis: The investigators will use an intention to treat approach to the analysis.
Categorical baseline data will be analyzed using the Fisher exact probability test.
Non-categorical baseline data will be analyzed using the Student t test. SSI rates will be
determined using the Fisher exact probability test.
Hypothesis: Wound protectors will reduce the SSI rate in patients undergoing a
pancreatoduodenectomy with preoperatively placed intrabiliary stents.
Potential Impact: Given the tremendous oncologic, economic, and psychological impact of SSI
following pancreatoduodenectomy, the epidemic incidence of this complication must be
reduced. The additional crippling effect of refusing (Medicare) payment for any patient who
receives a SSI in the United States has launched all techniques and analyses that can
potentially reduce this complication into the National health care agenda. In Canada, health
care utilization and economics are always a relevant and ever expanding area of importance.
It is crucial that the investigators reduce complications such as SSI, regardless of
individual payer sources.
- Surgical Site Infection (SSI) Rate
The Department of Surgery at the University of Calgary has a long and proud tradition of
research surrounding surgical site infections (SSI). More specifically, former surgeon and
Department Chair Dr. Peter Cruse prospectively studied 23,649 surgical wounds following
operative intervention. This massive study remains unmatched in size by a single institution
publication. Dr. Cruse and Ms. Rosemary Foord demonstrated a decrease in SSI rates with the
pre-surgical use of hexachlorophene wash and by not shaving the surgical site1. They
observed an increase in SSI rates with advanced age, use of drains, prolonged hospital stay
before the operation, and longer operative times. Dr. Cruse is directly responsible for
confirming the validity of the wound classification system currently in use throughout the
world (clean, clean-contaminated, contaminated, and dirty). We propose to carry on the
tradition of this line of investigation, reinforcing Calgary as a world leader in SSI
SSI are a frequent and costly source of post-operative morbidity. They are the most common
complication following gastrointestinal and biliary tract surgery, occurring in 5-30% of
patients. SSI are associated with a two-fold increased risk of in-hospital mortality, a 50%
increase in intensive care admission, a 6-day mean increase in hospital stay, and a
five-fold increased rate of readmission. SSI also have additional and highly negative
consequences in the treatment of oncology patients. More specifically, medical oncologists
wait until all operative wounds are entirely healed prior to beginning adjuvant
chemotherapy. This delay is both oncologically concerning, as well as psychologically
destructive to highly stressed patients with poor associated survivals. Furthermore, with a
significant SSI, this delay often leads to a total omission of adjuvant therapies as a
whole. The estimated increased cost per SSI ranges from $1,300 to $5,000 in the United
States. In Canada, a 1998 study estimated $3,937 per infection, resulting from increased
hospital stay, as well as emergency department and clinic visits. The implications of these
costs have now become paramount given that both U.S. Medicare and Medicaid currently deny
any reimbursement for patients who obtain an SSI while admitted to hospital. In addition,
patients who develop SSI experience psychosocial distress, loss of income, and loss of
productivity. Prevention of SSI is therefore a vitally important goal in delivering quality
care to patients. The SSI rate is 40-50% in patients undergoing pancreatoduodenectomy with
intrabiliary stents, the population of interest for this study.
Wound protectors are devices designed to protect the abdominal wound tissue edges from
contamination and trauma during laparotomy. A major reason for their conception and use is a
theoretical reduction in risk of SSI. Various devices with similar intent have been
described since the 1960s, falling into two main design categories: (1) Those with an
internal and external ring connected by impervious plastic, and (2) Those with a single,
internal ring connected to a drape which extends outward, over the wound edges and onto the
abdomen where they are affixed with adhesive or clips.A recent meta-analysis of randomized
controlled trials was conducted by a team led by the Principal Investigator to evaluate
whether impervious plastic wound protectors reduce the risk of surgical site infection
following gastrointestinal and biliary surgery. Six studies representing 1,008 patients were
included. Wound protectors were associated with a 45% decrease in SSI (p = 0.04). The Alexis
Wound Protector, a ring based model, had evidence of superiority to other products and has
been selected for this study based on this finding.
Recruitment: Contact information for study candidates will be obtained by the project's
research fellow from the offices of the participating (4) surgeons. Patients will be
contacted prior to their surgery by the research fellow and will be provided information
regarding the study. Patients who consent to participate will be randomized.
Randomization process: This study is a simple, two-arm randomized clinical trial (RCT) with
block randomization. Allocation will be concealed before the patient enters study. Patients
will be randomized by the Research fellow following consent. Allocation will be provided to
surgeon in a sealed envelope to be opened immediately before surgery. Patients and the data
analyst will be blind to allocation; the surgeons cannot be blinded. Charts will be blinded
for data abstraction.
Data collection: Information will be collected by chart review from the operative report and
patient records by the research fellow in the Department of Surgery.
Data elements to be collected include:
Date of birth, Sex, American Society of Anesthesiologist (ASA) score, Surgeon, Site (if more
than one facility), Fellow/resident/clerk present (y/n), Surgical procedure, Antibiotic
prophylaxis received (y/n) and time given, Information about repeat antibiotic prophylaxis
(for longer surgeries), Antibiotic type/combination, Type of wound protector and
manufacturer, Prep type (ETOH based, chlorhexidine based, iodine based), Hair removal,
Medications given, Packing, Drains, Wound classification, Wound closure technique & dressing
type, Length of surgery, Surgical suite infection control factors (e.g. UV, OR ventilation)
if these differ, Transfusions,
Current use of corticosteroids/immune suppressant, Preoperative chemotherapy, Smoking
history, Co-morbidities (diabetes, hypertension, etc.), Body Mass Index (BMI).
The presence of an SSI will be determined according to guidelines developed by the Centres
for Disease Control. More specifically, SSI is defined as being the presence of at least one
of the following:
1. Purulent drainage, with or without laboratory conformation, from the superficial
2. Organisms isolated from an aseptically obtained culture of fluid from the superficial
3. At least one of the following signs or symptoms of infection:
pain or tenderness, localized swelling, redness and superficial incision is
deliberately opened by surgeon, unless incision is culture-negative.
4. Diagnosis of superficial incisional SSI by the surgeon or attending physician.
We will use an intention to treat approach to the analysis to avoid the effects of crossover
and dropout. To achieve a power (superiority trial) of 90%, and alpha of 0.05 with a 5%
crossover and a 40% expected SSI rate in control versus 10% in wound protector groups, the
total sample size is 78 (i.e. 39 in each arm).
This project will capitalize on an existing research team who can work collaboratively with
the Principal Investigator and research assistant to carry out the project effectively and
efficiently. The current research team includes a clinical research fellow with experience
recruiting research participants from this patient population and a project manager who can
assist with ethics applications, manuscript writing and reporting. Additionally, the
Principal Investigator will benefit from mentorship by an experienced investigator who can
provide guidance not only on methodology, interpretation of data and publication strategies,
but also on the day-to-day logistics of running a research project.
View this trial on ClinicalTrials.gov