A Comparison of Hydrosurgery, Pressurized Pulsatile, and Bulb Syringe Lavage Irrigation Methods for Removing
Bacteria from Fracture Implants
+1Hughes, M S ; 2 Moghadamian, E S; 3Yin, L Y; 1Della Rocca, G J; 1 Crist, B D
+1University of Missouri-Columbia, Columbia, MO, 2University of Kentucky, Lexington, KY, 3Ohio State University, Columbus, OH
cristb@health.missouri.edu
INTRODUCTION:
Surgical site infection is a common form of nosocomial infection that
can occur in both open and closed fractures following internal fixation.
Table 1
Treatment of these infections has traditionally included preserving stable
Std. Error of
Group
Mean
Range
implants while the fracture is healing, via debridement and antibiotic
Mean
administration to combat the infection. Recent evidence indicates that
1.58 x 10 8 6.66 x 10 7 – 2.63 x 10 8 2.33 x 10 7
Control
this algorithm results in less than optimal rates of fracture union and of
2.48 x 10 5
infection eradication. Novel approaches to eradicate bacteria from
Bulb Syringe
5.5 x 10 4 - 8.5 x 10 5 9.37 x 10 4
implants, such as hydrosurgery technology, while maintaining rigid
Low Pressure
573
67- 1.28 x10 3
149
stability of healing fractures may improve clinical outcomes.
Pulsatile
50
Hydrosurgery
0-166
22
METHODS:
Stainless steel 4-hole non-locking 3.5mm fracture plates (Smith &
Nephew, Memphis, TN) were divided into 4 different groups with 8
plates in each group. Staphylococcus aureus (ATCC 29213) was
incubated in 15ml of tryptic soy broth overnight at 370 C. The bacterial
broth was then centrifuged for 10 minutes and the broth was removed
and replaced with 5ml of sterile 0.9% saline solution. After vortex
mixing, a sample was removed for bacterial quantification. An aliquot
equaling 1x106 bacteria was then inoculated into 7.5 mL of tryptic soy
broth. One plate was then placed into each container of bacterial broth
and then mixed for 10 seconds on a vortex and placed into an incubator
overnight at 370 C. The plates were then were divided randomly into 1
of 3 different irrigation groups or 1 control group that did not undergo
any irrigation. All plates were removed from the bacterial broth with
sterile instruments, and the experiment was performed in a laminar flow
biological safety cabinet. Each of the experimental groups was irrigated
with 1 L of 0.9% normal saline solution using one of three irrigation
methods. The first experimental group included plates that were
irrigated utilizing a bulb syringe (Kendall, Mansfield, MA). The second
group utilized pulsatile lavage (InterPulse Irrigation System; Stryker
Instruments, Kalamazoo, MI) operated at its highest setting, using a
high-flow tip attachment. The third group utilized a hydrosurgery
debridement system (Versajet, Smith & Nephew, Memphis TN) with the
power set at level five (available range 1-10). Bulb syringe and pulsatile
lavage irrigations were directed 3 cm from the plate during testing.
After irrigation, each specimen was placed in 5.0 ml of sterile saline and
sonicated with an intermediate size probe for 30 seconds set at 0.6 In
each of the variable groups, 10µl samples of undiluted sonicate, 1:100
dilution, and 1:1000 dilution were cultured in triplicate on sheep blood
agar plates. The culture plates were incubated for 24 hours at 370 C and
the colonies were counted.
A Wilcoxon Rank Sum test was used to assess for equality of group
means. A natural log transformation was used since the bacterial counts
had a large range of values. It was determined that a sample size of 8
plates would be large enough to detect an effect size of 2.0 when using a
two-tailed paired t-test with a power of 0.80 and a significance level as
small as 0.01.
RESULTS:
The residual bacterial loads found on the plates are listed in Table 1.
Each irrigation method group (bulb syringe, pressurized pulsatile, and
hydrosurgery) had significantly reduced levels of bacteria adherent to
the plate following irrigation when compared to the control group (p=
0.0002). Amongst the irrigation methods, both the pressurized pulsatile
lavage and hydrosurgery groups had significantly reduced bacteria levels
compared to the bulb syringe group (p= 0.0002) and the hydrosurgery
group had significantly fewer residual bacteria than the pressurized
pulsatile lavage group. (p=0.0012)
DISCUSSION:
Surgical wound infection is recognized as a complication that must be
improved upon by the medical community and has been highlighted in
national initiatives, such as the Surgical Care Improvement Project
(SCIP). Although prevention is the goal, our focus should also include
improving the treatment of such infections. The treatment of infected
acute fractures stabilized with internal fixation is a particularly difficult
challenge that deserves further investigation. Minimal data directly
addresses this issue in the literature. Current management guidelines
include retention of stable fracture implants, debridement of the wound,
and administration of culture-specific antibiotics. A recent study
questioned the efficacy of this treatment regimen, noting only a 68%
union rate. A 50% rate of infection recurrence was also noted in those
fractures that ultimately achieved fracture union.
There is considerable debate as to which irrigation delivery device
achieves the optimal balance between removing bacteria from implant
surfaces and minimizing damage to the surrounding tissues. Pressurized
pulsatile lavage has been shown to be more effective in removing
particulate matter, necrotic tissue, and bacteria, as compared to standard
irrigation methods, such as use of a bulb syringe. However, pressurized
pulsatile lavage has been shown to alter osteoblast differentiation
damage cortical bone and soft tissue potentially leading to higher
clinical infection rates, compared to bulb lavage. Despite the numerous
animal and in vitro studies, there is no human clinical data
demonstrating that one method of irrigation delivery is superior in
eradicating implant-associated infections.
The Versajet hydrosurgery system utilizes the Venturi effect of fluid
dynamics to simultaneously cut and aspirate tissue. The Versajet has
been shown to reduce operating room time while having comparable
wound healing times, as compared to knife debridement and pulse
lavage. There is also evidence that the Versajet system decreases
bacterial load in burn wounds.
Debridement is often quoted as being the key component to the
irrigation and debridement procedure, and the hydrosurgery system may
be thought of as a debridement tool for tissues and an irrigation tool for
metallic implants. The concept of using a debridement tool such as the
Versajet on metal implants, as compared to traditional irrigation
methods, presents a novel approach to infected fracture and nonunion
management. The data in this study suggests a statistically significant
decrease in residual bacterial loads with the hydrosurgery system as
compared to all other irrigation systems, and represents a potential
method of removing bacterial colonization while retaining stable
implants to promote fracture healing.
Limitations of this study include the in vitro design, which does not
effectively recreate the many components of the fracture healing
environment. In this study, only one type of bacterial organism was
used, while it has been documented that in clinical settings, multiple
organisms can act synergistically to create a complex infected wound.
Furthermore, only one power setting was used on the hydrosurgery and
pulsatile lavage irrigation systems which can affect debridement
capabilities.
The hydrosurgery system removes significantly more bacteria than
other devices tested in this in vitro model. Further in vivo testing is
required to determine if this difference is clinically significant.
Poster No. 2143 • 56th Annual Meeting of the Orthopaedic Research Society