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Acticoat* Clinical Evaluation LMarin

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A clinical evaluation of the use of an antimicrobial barrier silver foam dressing* to prevent post-surgical infections in external fixator wire sites.


Luis E Marin, DPM and Elizabeth Hernandez, DPM, Marin Foot and Ankle Center, PA, Hialeah, Fla.

 

Introduction.
Pin tract infection is the most common complication when using external fixators. The rate of infection ranges from 0.5%-30% and the incidence of chronic osteomyelitis, after external fixation has been reported to be between 0%-4%, Parameswaran et al., (2003). Checketts and Young, (2003) stated the incidence of minor infection to be as high as 18%. Pin tract infections after external fixation remains a clinically challenging problem. This dilemma becomes more taxing when there is no clear definition of pin site irritation, pin site infection, and pin tract infection. Pin tract infections can decrease the stability of the pin-bone interface which can lead to the failure of fixation with consequent loss of alignment of the fracture or fusion site. It can also lead to osteomyelitis and systemic infection, which may be both costly and difficult to treat, Temple and Santy, (2004).

 

This problem is exacerbated by the fact that there is no standard in pin site care for external fixators. The Cochrane Collaboration review titled, “Pin site care for preventing infections associated with external bone fixators and pins” concluded that “there is a complete absence for any particular strategy for pin site care.” They also stated that “no clinical trials were identified that considered methods of cleansing or different types of dressings.” Parameswaran et al., (2003) state that additional methods of preventing pin tract infection need to be developed.


Definitions
Infection in an acute wound has been defined as “the presence of one or more of the following criteria; abscess, cellulites, discharge, (serous exudate with inflammation, seropurulent, haemopurulent, pus) delayed healing, discoloration, unexpected pain/tenderness/bridging of the epithelium or soft tissue, abnormal smell, or wound breakdown” Cutting K F et al., (2004). This can occur with or without the signs of
leukocytosis and fever.

 

Pin Site Irritation has been defined as - any pin site with redness, itching or is bothersome to the patient, Marin (Author definition).

 

Pin Site Infection - this includes the definition of infection above, with the addition of any pin site in which a positive culture was taken and soft tissue was involved, Marin (Author definition).

 

Pin Tract Infection - this includes any pin site in which the pin had to be removed prematurely and bone was involved, Marin (Author definition).

 

The Evaluation.
A single-center, unblinded, prospective, randomized, intrapatient comparative clinical evaluation. Patients received three types of treatment: the test article (antimicrobial barrier silver foam dressing*) as well as the control dressing (Gauze) and a comparative treatment (Bacitracin/Neomycin/Polymyxin B Sulphate Ointment**). The patients individual wire sites were randomized to treatment according to a predetermined randomization schedule. Three external fixator circular frame rings were selected, (upper/middle/ lower-foot plate) and all the wires associated with that ring were treated with the same treatment. All three treatments were run concurrently for the duration of the evaluation (28 days) and all wire sites were assessed individually.

 

Assessments were carried out post-op day 3, day 7 and then weekly assessments for four weeks. Bacterial cultures were taken at each dressing change and a clinical assessment of each individual wire site was carried out according to the definitions cited in this presentation. The swabs were sent to a central laboratory for analysis.

 

The primary objective of the evaluation was to compare the incidence of infection at the treated orthopaedic percutaneous wire site between the antimicrobial barrier silver foam dressing* (test), Bacitracin/Neomycin/Polymyxin B Sulphate Ointment**, (Comparative dressing) and Gauze (Control). Secondary objectives included the cost of treatment of pin site infections.


68 pin sites (3 males and 2 females) have been included into the evaluation. 20 pin sites have been treated with the test article, 22 pins treated with gauze, 26 pins treated with the comparator dressing. All patients were; >18 years of age, male or non-pregnant females that have suffered a long-bone fracture, or were undergoing reconstructive surgery of the lower extremity, that required external fixator placement. All patients were undergoing the initial placement of the external fixator in the operating room (OR). All patients understood the aims of the evaluation and consented to taking part in the evaluation. Full IRB approval was obtained before initiating the evaluation.

 

Results

  • 1 pin developed an infection (clinical signs confirmed with a positive culture) treated with Bacitracin/Neomycin/Polymyxin B Sulphate Ointment**
  • 1 pin developed an infection (clinical signs confirmed with a positive culture) treated with the gauze dressing
  • No pin sites treated with the test article (antimicrobial barrier silver foam dressing*) developed a pin site infection
  • Three swabs came back positive for bacterial growth, but did not develop a clinical infection (1 Bacitracin/Neomycin/ Polymyxin B Sulphate Ointment**, 1 gauze and 1 test article)
  • Both clinically infected pins required treatment with systemic antiobiotics (ciprofloxacin***) 750mg BiD for 7 days then levofloxacin**** 500mg qd for 7 days
  • Both clinically infected pins required increased dressing changes

 

Conclusions
The incidence of infection in our evaluation has been low, compared to the literature. A total of 68 pin sites only 2 pins (2.9%) became infected, according to clinical signs confirmed by a positive swab culture. The two infected pins were on the control arm (gauze) and the comparator arm (Bacitracin/Neomycin/Polymyxin B Sulphate Ointment**). None of the pins treated with the test article (antimicrobial barrier silver foam dressing*) became clinically infected. The cost of treatment for an infected pin was $307.79 (Horizon Drugs) in antibiotic costs alone. The cost of treatment with the test article would have only been $66.00. The infected pins required increased dressing changes from once a week to every three days.

 

Our initial findings from this evaluation is that the antimicrobial barrier silver foam dressing* is an effective antimicrobial barrier and an effective prophylactic measure in the prevention of external fixator wire sites developing a pin site infection. The dressing is now suggested as a new dressing protocol for the treatment of pin sites in an area where the Cochrane Collaboration has concluded that there is no current strategy.

 

References
Cutting K F and Richard White (2004). Defined and refined: criteria for identifying wound infection revisited. Wound Care, March 2004.


Checketts, R G and Young C F (2003). Mini- Symposium: Tibial Fractures. External fixation of diaphyseal fractures of the tibia. Current Orthopedics (2003) 17, pps. 176-189.


Horizon Drugs - www.horizondrugs.com 


Parameswaran Dushi A, Craig S Roberts, David Seligson and Michael Voor, (2003). Pin Tract Infection with Contemporary External Fixation: How much of a problem? Journal Of Orthopedic Trauma, Vol. 17, No 7, pps. 503-507. March 2003.


Temple J and Santy, J (2004). Pin site care for preventing infections associated with external bone fixators and pins. The Cochrane Database of systemic reviews 2004, Issue 1

 

Case Study Case Study Image Case Study Case Study
1. Patient 2 in OR 2. Test article in situ 3. Patient 2 - Most traumatic pin treated with test article 4. Pin at week 4 looking healthy
Case Study Case Study Case Study Case Study
5. Patient 5 - Pre-infected pin
(upper ring) at Day 3 treated with Gauze
6. Patient 5 - Infected pin at week 4 treated with Gauze 7. Patient 5 - Pre-infected pin
(lower ring) at Day 3 treated with comparator dressing
8. Patient 5 - Infected pin at week 4 treated with comparator dressing

 

 

Nanocrystalline Silver is a patented technology of NUCRYST Pharmaceuticals Corp.
TM SILCRYST is a trademark of NUCRYST Pharmaceuticals Corp, used under licence

* ACTICOAT (with SILCRYST™ Nanocrystals) Moisture Control antimicrobial barrier dressing - Smith & Nephew Wound Management Inc., Largo, Fl.
** Triple Antibiotic Ointment
- Moore Medical Corp., New Britain, Conn.
*** Ciproxin - Bayer Healthcare, Newhaven, Conn.
**** Levaquin - Ortho McNeil Pharmaceutical Inc., Raritan, N.J.
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