A Retrospective Study: Clinical ExperienceUsing Vacuum-Assisted Closure in theTreatment of WoundsSuresh Antony, MD, FACP and Sandra Terrazas, PTCWS, CLTEl Paso, Texas

We report the results of our wound care experience usingthe wound vac as an adjunct theropy in the treatment ofsternal, spinal, and lower-extremity wounds. This is a retro-spective study in which 42 patients were evaluatedbetween 1999 and 2002 for nonhealing sternal, spinal, andlower-extremity wounds. There were 12 potients with sternalwounds with a vanety of pothogens who were treoted withantimicrobiols along with the wound VAC. The VAC wasapplied for an average of 12 days, and all 12 potients wentonto complete closure by the end of four weeks. There were14 patients in the lower-extremity wound group, again, witha voriety of pathogens. The VAC wos placed for an averageof 29.3 days to achieve closure along with the wound VAC.There were 16 spinal wound patients with a variety ofpathogens. All the patients received antimicrobial therapy,with the average duration of the VAC beings 27.6 days andclosure taking about eight weeks. The wound VAC, alongwith appropriote antimicrobial therapy and surgery,appears to help reduce the number of days to healing,along with a reduction in the number hospital days and pos-sibly costs to the health system.

Key words: wound VAC U wound heoling

@2004. From the Texas Tech University Health Sciences Center/U.S. OncologyPA, and Diamond Rehabilitation Center, El Paso, TX. Send correspondenceand reprint requests for J NatI Med Assoc. 2004;96:1073-1077 to: SureshAntony, 7848 Gateway E., El Paso, TX 79935; e-mail: santony@elp.rrcom

INTRODUCTIONSeveral million patients suffer from nonhealing

wounds in a variety of anatomical sites, costing thehealth system millions of dollars. The cost and man-agement of these wounds varies in different centers.For example, the cost of managing a diabetic footinfection for approximately two weeks in one centeris between $20,00O$25,000 but may be quite differ-ent in another center.' Prior to the advent of thewound VAC, the treatment of nonhealing woundsconsisted of traditional modalities, such as wet-to-dry dressings, debridement, and topical antibiotics,with closure ofthese wounds taking several weeks ormonths.2 The process of wound healing is a complexone, consisting of cell migration leading to repair andclosure of wounds. The process also needs removalof debris, control of infection, clearance of inflam-mation, angiogenesis, deposition of granulation tis-sue, contraction, remodeling of the connective tissuematrix, and maturation. If any of these steps fail, achronic open wound without anatomical or function-al integrity results. Chronic wounds may be associat-ed with pressure, trauma, venous insufficiency, dia-betes, arterial disease, or prolonged immobilization.These wounds result in prolonged hospitalization,high risk of infection, and result in billions of dollarsin healthcare costs. The advent of the wound VAChas substantially increased wound closure rates andreduced morbidity and health costs for manypatients.'6 We present the clinical features, isolatedpathogens, and healing results of 42 patients seen inour institution with sternal, spinal, and lower-extrem-ity wounds treated with antimicrobial therapy,debridement, and woundVAC placement.

MATERIALS AND METHODSThere were 42 patients obtained in this retrospec-

tive study with a variety of infections to wounds,including sternal, (Figure 1) spinal (Figure 2), andlower extremity (Figure 3). Data was collected forage, sex, predisposing factors, microorganisms,duration ofwoundVAC application, and wound heal-

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ing rates. Appropriate wound cultures were obtainedfrom the sites after which antimicrobial therapy wasstarted, if needed. The patient underwent operativeand nonoperative debridement until healthy bleedingtissue and/or bone were revealed. Pulse lavage irriga-tion was utilized as well in some of the wounds. TheVAC was then applied to the wound. The wound wasevaluated every two to three days. The wound VACwas initiated by placing a foam dressing in the openwound. The polyurethane foam has a noncollapsibleevacuation tube embedded, a vacuum pump, and atransparent adhesive drape (KCI International, SanAntonio, TX) (Figures 4 and 5).

The foam used is a medical grade reticulatedpolyurethane foam with a 400-600-,umL pore size.Side ports of the evacuation tube below communica-tion of the lumen of the tube to spaces in the trabac-ulated foam and the open cell nature of the foamensures equal distribution of the applied pressure toevery surface ofthe wound that is in contact with thefoam. The foam is then cut and contoured to fit thesize of the defect. The foam is then connectedthrough the evacuation tube with the VAC pump.The wound is then sealed with an adhesive drape.The suction generates enough vacuum in the wound,producing a high-contact zone in the wound foaminterface, and a vacuum seal is then achieved.5'7 Thepolyurethane foam is then changed every two-to-three days with the drainage tube. This makes it pos-sible for the wound to be inspected and avoids in-

Figure la. Pre-VAC Sternal Wound

Figure lb Post-VAC Sternal WoundShowing Closures h' I~~~~

growths of tissue into the foam. A container on theside ofthe VAC collects the wound exudate, which ischanged weekly or upon filling capacity. The pumppressure is set between 125-150 mmHg dependingon patient's level of tolerance. Debridement withenzymatic compounds was occasionally usedbetween dressing changes until good granulation tis-sue was present or until closure of the wound wasachieved. Nonhealing wounds were defined aswounds that did not close two or more weeks afteroperative intervention or dehisced after closure.

RESULTSForty-two patients were evaluated between 1999

and 2002 for nonhealing sternal, spinal, and lower-extremity wounds. There were four patients on oralsteroids, and none of the patients were on antigraftrejection drugs.

STERNAL WOUNDSThere were 12 patients with sternal wounds fol-

lowing coronary-artery-bypass grafting. The aver-age age was 72 years. There were eight males andfour females. All 12 patients had diabetes and coro-nary artery disease. Pathogens isolated includedStaphylococcus (eight), Pseudomonas (two), mixedinfection (one), and Candida (one). All 12 patientswere treated with antimicrobials concomitantly withthe wound care. No complications were observed.One patient had recurrence of the infection with thesame pathogen and was retreated with success. TheVAC was applied for an average of 12 days (rangetwo-to-23 days). All 12 patients went onto completewound closure by the end of four weeks.

LOWER-EXTREMITY WOUNDSThere were 14 patients in this group with an aver-

age age of62 years. Eight ofthe patients had diabetes,coronary artery disease, and peripheral vascular dis-ease. Isolated pathogens included Staphylococcus(four), gram-negative pathogens (one), and anaerobes(one), and no cultures were obtained in eight patients.All 14 patients received antimicrobial therapy; onepatient did not respond to therapy and had to undergoan above-knee amputation, while another underwentsurgical closure. The woundVAC was applied with anaverage of29.3 days, range of four-to-I 86 days.

SPINAL WOUNDSThere were 16 patients in this group with an aver-

age age of 59 years, five males, and 11 females.Eight ofthe patients had diabetes in addition to otherpredisposing conditions, such as rheumatoid arthri-tis and spinal stenosis. Infecting pathogens includedStaphylococcus (15), Enterococcus (two), Candida(two), Pseudomonas aeruginosa (one), and a mixed

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infection (three). All 16 patients received antimicro-bial therapy. One patient expired of unrelated caus-es. Recurrence of infections occurred in two patientswho went onto successful healing once they wereretreated. Eight patients went on to surgical closure,while the remaining eight patients went onto com-plete wound closure. Average length ofVAC appli-cation was 27.6 days. (range two-to-178 days). Theduration to wound closure was about eight weeks.

DISCUSSIONThe first case, in which negative pressure was

used in the treatment of pressure ulcers and chronicwounds, was described in 1993 by Argenta et al.8Since then, it has been used in a variety of wounds,including diabetic ulcers, abdominal wounds, ster-nal wounds, and spinal wounds.5'7'9- The principle ofnegative pressure includes promotion of granulationtissue by arterial dilatation.'2 The device also hasbeen shown to reduce edema, bacterial colonization,and reduce excess fluid.'3 These effects seem toshorten the duration of wound healing as noted in aprevious report and suggested by this study. It hasbeen suggested that successful healing correlateswith less than 1O' organisms per gram of tissue. Thenumber achieved with wound VAC therapy is usual-ly less than 10.5

Complications with the wound VAC are infre-quent if the patient population is properly selected.These include bleeding from the wound at the time

Figure 2a. Pre-VAC Spinal WoundIS ... ... ' . :!,'...s _

Figure 2b. Post-VAC Treatment ofSpinal Wound

of sponge change due to excessive growth of granu-lation tissue into the sponge if it has been left inplace longer than 48-72 hours. Pain has been associ-ated with sponge changes but usually is short livedand can be controlled with oral narcotics. Occasion-ally, odor may be a problem, and one needs to ascer-tain that there is no active infection present. Allergicreactions to the drape have been reported as well,and these have been managed with topical steroidsor antihistamines.'4

Sternal wound infections have been quite a prob-lem in terms of healing until the advent of the VAC.In one paper, 16 patients with sternal wound infec-tions were treated with the combination of antimicro-bials, debridement, and VAC therapy with goodresults.'5-'7 None of these patients had any complica-tions and had shorter hospitalization stays, earlierextubation, and better outcomes when compared topatients treated with normal saline dressing changes.

In lower-extremity wounds, such as graft siteinfections, there appears to be a reduction in exu-dates and bacteria with rapid formation of granula-tion tissue especially when compared to traditionalmethods of treatment.4 Complications with thismethod are negligible and compares with our expe-rience as well.

In spinal wounds, the occurrence of serious com-plications is around 4% but can be as high as 20% insome series.18'19 These wounds may be associatedwith exposure of vertebral canal, spinal sac, and

Figure 3a. Pre VAC Treatment Lower

Figure 3b. Post-VAC TreatmentLower-Extremity Wounds Extremity Wounds

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Figure 4. Wound VAC in Place with Sponge

Ft~~~~~~~~~~~~~~~~Shardware. Significant morbidity and mortality existswith these wounds, and the average cost for treatingthese patients is approximately $100,000 per patient.Some investigators have found successful closure ofspinal wounds can be achieved much more rapidlythan traditional methods in patients being able to tol-erate the device. Animal studies using pigs withwounds were studied to validate the efficacy of thewound VAC. These animal models were studied todocument the rate ofwound healing using subatmos-phere pressure and by laser doppler probes to meas-ure blood perfusion. Bacterial clearance studies wereconducted by infecting wounds with s. aureus and s.epidermis, the results of which showed reduction inthe bacterial load, longer flap survival, and increasedrate of granulation.20

Nonhealing wounds can be associated with dia-betes; venous stasis ulcers; prolonged nonmobiliza-tion; and postoperative wounds, such as deep, persist-ently infected spinal wounds, etc. The treatment ofthese wounds is costly, demanding lengthy hospitalstays and incurring both psychological and emotionalstress to patients. The advent of the VAC appears tohave helped such wounds achieve faster healing,shorter hospital stays, and reduction in the overallcost. Our study presents a series of patients with avariety of infections in which the wound VAC wassuccessfully used. In our experience, it appears thatmost of these wounds occurred in the elderly with ahistory of diabetes mellitus, coronary artery disease,and peripheral vascular disease with the predominantpathogen isolated being Staphylococcus. Patients whodid not receive antimicrobials but were treated withthe VAC and debridement alone also healed withoutany adverse outcomes. The optimum duration ofapplication of the VAC has not been well-establishedbut seems to vary depending on the site where thewound occurred, vascularity, and infection. Thewound VAC in combination with antimicrobial thera-py and surgical debridement should be standard-of-care soon in the treatment of difficult to heal wounds

Figure 5. Wound VAC Showing Active andDrainage Tube Drainage of Fluid

such as sternal, spinal, and lower-extremity or graftsites. Further studies need to be done to evaluate theefficacy of the wound VAC with these types ofwounds, and to access the safety and clinical efficacyof this modality oftreatment

REFERENCES1. Hibbs P. The economics of pressure ulcer prevention. Decubitus. 1 989;2:32-38.2. Lazarus GS, Cooper DM, Knighton DR. et al. Definitions and guidelines forassessment of wounds and evaluation of healing. Arch Dermatol. 1994;130:489-493.3. Joseph E, Hamod CA, Bergman 5, et al. A prospective randomized rnal ofvacuum-assisted closure versus standard therapy of chronic nonhealingwounds. Wounds. 2000 12:60-67.4. Demaria R, Giovannini UM, Teot L, et al. Using VAC to treat a vascularbypass site infection. Jounal of Wound Care. 200x1eo10: r2-13.5. Argenta LC. Vacuum device can speed healing. Wound Care. 1997t29.6. Argenta LC. Vacuum-assisted closure case. Wound Care. 1997:30-31.7. Mullner T, Mrkonjic L, Kwasny 0, et al. The use of negative pressure to pro-mote the healing of tissue defects: a clinical trial using the vacuum-sealingtechnique. BrJ Plast Surg. 1997;50:194-199.8. Argenta LC, Morykwas M, Rouchard R. The use of negative pressure topromote healing of pressure ulcers and chronic wounds in 75 consecutivepatients. Presented at the Joint Meeting of the Wound Healing Society andEuropean Tissue Repair Society, Amsterdam. August 1993.9. Blackburn JH, Boemi L, Hall W, et al. Negative pressure dressings as a bol-ster for skin grafts. Ann Plast Surg. 1998;40;453-457.10. Jones G, Jurkiewicz, MJ, Bostwick J, et al. Management of the infectedmedian sternotomy wound with muscleflaps: the Emory 20-year experi-ence. Ann Surg. 1997;225:766-778.11. Obdeign MC, De Lange MY, Lichtendahl DH, et al. Vacuum-assistedclosure in the treatment of poststernotomy mediastinitis. Ann Thorac Surg.1999:68:2358-2360.12. Argenta LC, Morykwas M. Vacuum-assisted closure: new method forhealing chronic wounds. Presented at the 73rd annual meeting of theAmedcan Association of Plastic Surgeons, St. Louis, MO, May 1994.13. Morykwas MJ. Faler BJ, Pearce DJ, et al. Effects of varying levels of sub-atmospheac pressure on the rate of granulation tissue formation in expe-mental wounds in swhine. Ann PlastiSurg. 200ft47:547-551.14. De Franzo AJ, Marks MW, Argenta LC, et al. Vacuum-assisted closure forthe treatment of degloving injues. Plast ReconstrSurg. 1999.104:2145-2148.15. Hersh RE, Dahman JM, Dahman Ml, et al. The vacuum-assisted closuredevice as a bfdge to stemal wound closure. Ann PlastSurg. 2001:46:250-254.16. Tang AT, OhJ SK, Haw MP. Novel application of vacuum-assisted closuretechnique to the treatment of sternotomy wound infection. Eur J Cardio-thAmcr.ic 207iati a482-4o4.

17.4dinM.DeLrnoJ angeMY, Lihendah DH,et al. Vacuum-assisteddlo-ueo

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sure in the treatment of poststernotomy mediastinitis. Ann Thorac Surg.1999;68:2358-2360.18. Yuan-Innes MJ, Temple CL, Lacey MS. Vacuum-assisted wound closure:a new approach to spinal wounds with exposed hardware. Spine.2001 ;26:E1-E4.19. Klink BK, Thurman RT, Witpenn GP, et al. Muscle-flap closure for salvageof complex back wounds. Spine. 1994;19:1467-1470.20. Morykwas MJ, Argenta LC, Shelton-Brown El, et al. Vacuum-AssistedClosure: a new method for wound control and treatment: animal studiesand basic foundation. Ann Plast Surg. 1997;38:553-562. U

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