Surgical debridement with VERSAJET: an analysis of bacteria load of the wound bed pre‐ and post‐treatment and skin graft taken. A preliminary pilot study

Abstract

Surgical debridement, which is used for the removal of necrotic tissue from a wound, is becoming more and more important in the treatment of skin injuries. VERSAJET (VERSAJET™, Versajet Hydrosurgery System, Smith and Nephew, Hull, UK) is one of the techniques used for wound debridement. Medical literature does not present either analytical or comparative data correlating the bacterial load with the VERSAJET treatment. For this reason, we have decided to carry out a study to evaluate the level of bacterial contamination before and after the surgical debridement treatment with VERSAJET and, in connection with this, the correlation between the bacterial load and the successful healing of the skin graft. We took a total of 100 bacteriological swabs, 50 before and 50 from 27 selected patients after the treatment with VERSAJET, with which the wound bed was prepared to receive the skin graft or Integra graft in order to acquire data about the level of bacterial contamination. After analysing all those data we can assume that reducing the bacterial load is not the only variable which the successful healing of the skin graft depends on. In conclusion, there is still many data to analyse and study in order to better understand the qualitative and quantitative presence of bacteria and the success of this future surgical procedure. We remind that the performance of this study was not sponsored by any company.

INTRODUCTION

There are several wound debridement techniques available to the surgeon. The preparation of the wound bed can be made by means of enzymatic, autolythic, mechanical, biological and osmotic debridement (1). These techniques allow to remove the necrotic tissue, reduce the bacterial load and convert the wound into an acute wound. Surgical debridement by scalpel of the necrotic tissue is the gold standard and it is an essential part of treating a wound before considering any reconstructive surgery option. This procedure, however, even if it is carried out quickly, can be painful and non selective, because it may also remove healthy tissue. There are also other mechanical forms of debridement, such as pulsed lavage, ultrasound and VERSAJET debridement. All through the years, these techniques have passed from supplementary to more and more common, both in surgery rooms and in clinical situations.

VERSAJET is a debridement tool which makes use of an innovative technology based on a jet of water and on the Venturi effect resulting from it, which is capable of demolishing and, at the same time, removing by suction the necrotic tissue 2, 3. This treatment is well tolerated by the patient and drastically reduces the bacterial load (3). There is little data in medical literature which compares and analyses the bacterial load before and after the surgical debridement treatment with VERSAJET and the correlation between the bacterial load and the success of future surgery procedures. For this reason, within the Plastic and Reconstructive Surgery Department of Azienda Ospedaliero‐Universitaria San Giovanni Battista of Turin, Italy, we have sample‐swabbed patients who showed skin injuries ready to be grafted after preparation of the wound bed using VERSAJET. The sample swabs were taken before and after the use of VERSAJET.

The scope of our study has been to evaluate the change in bacterial load before and after the unbridling treatment with VERSAJET and the correlation between the bacterial load and the positive or negative result of graft taken or graft integration.

MATERIALS AND METHODS

VERSAJET utilises a jet of sterile saline solution and the Venturi effect resulting from it, which is capable of demolishing and, at the same time, sucking the necrotic tissues and debris. The system consists of a power console with power regulation through an activating foot pedal, disposable single‐use hand piece and tubing set connected with an appropriate vacuum waste container. The hydro surgery system ejects a high speed, high pressure jet of sterile saline solution (265–670 mph and 103–827 bar, depending on the 10‐step speed setting on the console) parallel to the wound surface, which is then collected in the vacuum waste container. The suction allows the surgeon to cut the tissue and suck the debris. The effects of cutting and sucking can be controlled through the power settings on the console. The operator can adjust the jet of liquid by regulating the liquid pressure and speed and by modifying its direction.

With the approval of our hospital's management and having obtained the informed consent of the patients, starting from 7 July 2008 and up to 12 September 2009, within the Plastic and Reconstructive Surgery Department of Azienda Ospedaliero‐Universitaria San Giovanni Battista of Turin, Italy, we selected 27 patients (Table 1), of which 15 male patients and 12 female patients, with an average age of 69·3 (age between 49 and 86), to be treated with VERSAJET. In 26 of them, the skin injuries were located in the lower limbs and in 1 (one) case in the back. The associated pathologies that were diagnosed in most of those patients were diabetes, high blood pressure and vascular pathologies. We took a total of 100 bacteriological swabs, 50 before and 50 after the treatment with VERSAJET, with which the wound bed was prepared to receive the skin graft or Integra graft (Table 1).

Table 1.

Baseline characteristics: patients treated with VERSAJET™ (VERSAJET™ Smith and Nephew, London, UK)

Patient	Age	Sex	Diagnosis	Location	Associated diseases	Number of swabs taken (pre + post )	Bacteria present pre‐treatment	Bacteria present post‐treatment	Change in bacterial colonisation a	Type of healing
1	66	M	Diabetic ulcer with tendine exposure	Lower extremity	Diabetes	2(1 + 1)	Negative	Staphylococcus aureus	Increased	Integra + skin grafting 100%
2	79	F	Chronic wound	Lower extremity		12(6 + 6)	S. aureus, Pseudomonas aeruginosa, Providencia stuartii, Bacilli gram positive	Enterococcus spp., Escherichia coli, GPPF b , Coagulase negative Staf, P. stuartii	Decreased	Skin grafting 100%
3	70	M	Necrosis from erysipelas	Lower extremity		4(2 + 2)	Streptococcus group C	Swab missing		Skin grafting 100%
4	65	F	Diabetic ulcer	Lower extremity	Diabetes	4(2 + 2)	Negative	Negative	No change	Skin grafting 100%
5	69	M	Diabetic ulcer	Lower extremity	Diabetes	10(5 + 5)	P. aeruginosa	P. aeruginosa	Decreased	Skin grafting 100%
6	78	M	Tissue loss	Lower extremity		2(1 + 1)	S. aureus, Enterococcus faecalis	S. aureus	Decreased	Skin grafting 90%
7	75	F	Vascular ulcer	Lower extremity	Vascular disease	4(2 + 2)	E. coli, GPPF, Enterococcus spp.	E. coli, Stenotrophomonas maltophilia, GPPF b	Decreased	Skin grafting 100%
8	63	F	Chronic wound	Lower extremity		4(2 + 2)	P. aeruginosa	GPPF b	Decreased	Skin grafting non successful
9	65	M	Epitelioma	Trunk		4(2 + 2)	S. aureus, Bacilli gram positive	Enterobacter cloacae	Increased	Skin grafting 100%
10	52	F	Diabetic ulcer	Lower extremity	Diabetes	4(2 + 2)	E. faecalis, Corynebacterium spp.	Corynebacterium spp.	Decreased	Skin grafting non successful
11	79	F	Tissue loss	Lower extremity		4(2 + 2)	S. aureus	S. aureus	No change	Skin grafting non successful
12	62	F	Diabetic ulcer	Lower extremity	Diabetes	4(2 + 2)	S. aureus, P. aeruginosa, Coagulase negative Staphylococcus, Proteus mirabilis, Alcaligenes spp.	P. aeruginosa, Coagulase negative Staf, P. mirabilis, Alcaligenes spp.	Decreased	Skin grafting non successful
13	72	M	Tissue loss	Lower extremity		2(1 + 1)	E. coli, P. mirabilis	P. mirabilis	Decreased	Skin grafting 100%
14	66	F	Chronic wound	Lower extremity		4(2 + 2)	S. aureus, S. faecalis	S. aureus, P. mirabilis	Increased	Skin grafting non successful
15	49	M	Tissue loss	Lower extremity		4(2 + 2)	S. aureus, P. aeruginosa, P. mirabilis	S. aureus, P. aeruginosa	Decreased	Skin grafting non successful
16	81	F	Cellulitis	Lower extremity		2(1 + 1)	Negative	Negative	No change	Skin grafting 100%
17	75	F	Tissue loss	Lower extremity		2(1 + 1)	S. aureus, Streptococcus viridans	Enterococcus faecium, S. viridans	Decreased	Skin grafting non successful
18	64	M	Diabetic ulcer	Lower extremity	Diabetes	2(1 + 1)	S. aureus, Pseudomonas spp.	S. aureus, Pseudomonas spp.	Decreased	Skin grafting 100%
19	79	M	Chronic wound	Lower extremity		2(1 + 1)	Negative	Negative	No change	Skin grafting 100%
20	73	F	Chronic wound	Lower extremity		4(2 + 2)	P. aeruginosa, S. aureus	P. aeruginosa, GPPF b	No change	Skin grafting 100%
21	80	M	Chronic wound	Lower extremity		4(2 + 2)	P. mirabilis, S. aureus	P. mirabilis, S. aureus	No change	Skin grafting non successful
22	73	M	Chronic wound	Lower extremity		2(1 + 1)	S. aureus	S. aureus	No change	Skin grafting non successful
23	73	F	Chronic wound	Lower extremity		2(1 + 1)	P. mirabilis, S. aureus	P. mirabilis, S. aureus	No change	Skin grafting 100%
24	65	M	Chronic wound	Lower extremity		4(2 + 2)	Negative	Coagulase negative Staf	Increased	Skin grafting 100%
25	75	M	Chronic wound	Lower extremity		2(1 + 1)	E. coli, S. aureus	S. aureus	Decreased	Skin grafting non successful
26	60	M	Diabetic ulcer	Lower extremity	Diabetes	4(2 + 2)	E. cloacae, GPPF b	E. cloacae, GPPF b	Decreased	Skin grafting non successful
27	65	M	Tissue loss	Lower extremity		2(1 + 1)	P. aeruginosa, S. aureus, P. mirabilis, Streptococcus agalactiae	P. aeruginosa, S. aureus, E. cloacae	Decreased	Skin grafting 100%

Total number of patient treated: 27; Mean age: 69 3; Male/Female: 15/12; Total number of swabs taken: 100.

^aFor the change in bacterial colonisation we have used the average of the semi‐quantitative evaluation (+, + + , + + + , + + + + ) of the bacterial flora performed on blood agar plates.

^bGPPF, Gram positive polymicrobial flora.

The swabs were taken from a skin surface of 5 cm × 5 cm from two random areas during the preparation of the wound bed, before and after hydrosurgery debridement, and were sown rolling the entire surface of culture plates. The microbiological unit of our hospital used the following plates: Columbia agar + 5% sheep blood (general purpose enriched non selective growth medium), CNA blood agar (enriched selective medium containing colistin and nalidixic acid for isolation of Gram positive cocci and bacilli), MacConkey agar (selective medium for isolation of Gram negative bacteria), Mannitol salt agar (MSA: selective medium for the isolation of Staphylococcus) and Chromagar (chromogenic medium for isolation and identification of yeast‐like fungi). Columbia blood agar and blood agar CNA plates were incubated at +35°C, in air enriched with 5% CO₂ for 18–24 hours, prolonging the incubation to 48 hours in case of negativity. The MacConkey agar, MSA and Cromagar plates were incubated at +35°C for 18–24 hours, prolonged incubation up to 48 hours if negative. The semiquantitative evaluation (+, + + , + + + , + + + + ) of the bacterial flora was carried out on blood agar plates. For the semiquantitative determination of the microbial load, the primary inoculum is made on non selective agar plate with a swab; then, a disposable loop is used to spread the material into the four quadrants of the plate by streaking the agar surface with a back‐and‐forth motion of the loop into each quadrant by turning the plate at 90° angles. The growth of colonies in each quadrant is proportional to the concentration of the inoculum and is expressed in a qualitative way from 1+ to 4+ according to the detection of colonies from first to fourth quadrant. The isolated micro‐organisms were identified preliminary on the basis of colony morphology, Gram and biochemical test spots (searching cytochrome c oxidase, catalase, coagulase, etc.).

For the final identification were used trading systems based on researching multiple different biochemical activities for different groups of micro‐organisms with manual methods (Enterotube, Becton Dickinson, New Jersey, USA), semiautomatic (API system, bioMérieux, Marcy l’Etoile, France) and/or automatic (Phoenix system, Becton Dickinson, New Jersey, USA; Microscan Walk Away, Siemens, Munich, Germany). The last two systems also allow the implementation of the anti‐biogram.

RESULTS

The most represented bacteria in the 50 pre‐treatment swabs of those patients that were analysed were Staphylococcus aureus (21 swabs), Pseudomonas aeruginosa, (15 swabs), Proteus mirabilis (8 swabs) and GPPF (Gram positive polymicrobial flora with prevalence of coryneform bacteria – 6 swabs), while 8 swabs did not contain bacteria.

The most represented bacteria in the 50 post‐treatment swabs of those 27 patients that were analysed were S. aureus (17 swabs), P. aeruginosa, (7 swabs), P. mirabilis (8 swabs) and GPPF (8 swabs), while 12 swabs did not contain bacteria (Figure 1).

Figure 1.

Representation of bacteria in post‐treatment swabs.

Fifty percent of the swabs analysed showed a decrease in the bacterial load, 17% showed an increase, while 33% showed no change.

In 8 patients the bacterial load remained the same, in 4 patients it increased, while in 14 patients it decreased. In one patient the post‐treatment swabs were missing (Table 1). Of those 27 patients, 16 showed skin graft taken, 11 showed skin graft not taken. Of this 11 non healed patients, 1 patient was amputated for vascular complications, 1 patient is going through healing process using electric stimulation and for the remaining 9 non healed patients the treatment was continued with a further wound debridement and then skin graft application. After the second treatment these nine patients showed skin graft taken. S. aureus was found in 4 swabs where skin graft was taken and in 10 where skin graft was not taken. The semi quantitative evaluation of S. aureus in the 4 swabs with skin graft taken was 2 times 1+ (50%), 1 time 2+ (25%) and 1 time 4+ (25%); in the 10 swabs with skin graft not taken was 8 times 4+ (80%), 1 time 2+ (10%) and 1 time 3+ (10%). P. aeruginosa was found in two swabs where skin graft was taken and in four where skin graft was not taken. The semi quantitative evaluation of P. aeruginosa in the two swabs with skin graft taken was two times 1+ (100%), in the four swabs with skin graft not taken three times 4+ (75%) and one time 3+ (25%). P. mirabilis was found in two swabs where skin graft was taken and in six swabs where skin graft was not taken. The semi quantitative evaluation of P. mirabilis in the two swabs with skin graft taken was two times 4+ (100%); in the six swabs with skin graft not taken was four times 4+ (67%) and two times 3+ (23%). GPPF was found in three swabs where skin graft was taken and in two where skin graft was not taken. The semi quantitative evaluation of the GPPF in the three swabs with skin graft taken was two times 1+ (67%) and one time 2+ (23%); in the two swabs with skin graft not taken was two times 3+ (100%). The negative bacterial load was found in nine swabs where skin graft was taken and in nine swabs where skin graft was not taken.

With increased bacterial load three skin grafts were taken, while one was not taken; with bacterial load unchanged five skin were taken, while three were not taken; with decreased bacterial load five skin grafts were taken, while seven were not taken.

DISCUSSION

Healing of chronic wounds is a very complex and difficult process. The debridement of the wound bed is quite an effective method that allows to prepare for a future graft and facilitates the healing process. Debridement of the wound bed leads to the removal of those barriers that hinder the healing process and which can be better understood by means of the TIME acronym, where T stands for tissue, I for inflammation, M for moisture, thus unbalance, and E for edges, which do not progress or are undermined (4). Therefore, the debridement must remove the necrotic tissue, treat the inflammation, correct the unbalance caused by moisture and treat the undermined edges which are not healing. The surgical debridement of the necrotic tissue by scalpel remains the gold standard for the most suitable preparation of the wound bed. This statement is confirmed by many data in medical literature 1, 5. It is, however, a painful and non selective method, because it may also remove sound tissue. The other debridement techniques, that is, enzymatic, autolythic, mechanical and biological, have the disadvantage of being slow processes which may require several days to develop 1, 3.

VERSAJET is a debridement technique, which utilises a jet of sterile saline solution at very high speed and the Venturi effect resulting from it, which is capable of demolishing and, at the same time, suck the debris and damaged tissue. When VERSAJET is used correctly, it can be selective, because it eliminates only the tissue aimed atthe liquid jet (6). The treatment is also well tolerated by patients (3). There are plenty of works showing the effectiveness of VERSAJET in the debridement and treatment of wounds 7, 8, 9. They state that VERSAJET seems to be a valuable equipment in necrotic and sloughy vascular ulcer debridement; it can often achieve an adequately clean bed with a single debridement step and can be able to prepare a smooth surface ready to receive a skin graft 3, 10. In medical literature, however, there are few data relative to the level of bacterial contamination before and after the surgical debridement treatment with VERSAJET and, connected with this, the correlation between the bacterial load and the successful healing of the graft. For this reason, we started this study within our department. After analysing the previously mentioned swabs, we noticed that the most represented bacterium was S. aureus followed by P. aeruginosa and P. mirabilis (Figure 1). On the basis of those data, we can assume that those bacteria are the main responsible of the non progress of the healing process of the wound and that their eradication facilitates healing of the wound (Figure 2). Our assumption is also confirmed by the analysis results of the swabs after treatment with VERSAJET which show that S. aureus was found in 4 skin grafts taken and in 10 that were not taken, P. aeruginosa in 2 skin grafts taken and in 4 that were not taken, P. mirabilis in 2 skin grafts taken and in 6 that were not. The negative bacterial load was present in nine skin grafts taken and in two that were not. This picture clearly shows that those bacteria can be responsible for the non healing of the skin grafts (Figure 3). We have to underline that in the skin grafts taken, where the bacteria were present, the semi quantitative evaluation of the bacteria load was low [we found 6 times 1+ (55%), 2 times 2+ (18) and 3 times 4+ (27%)]; in the skin grafts not taken the bacteria load was high [we found 15 times 4+ (68%), 6 times 3+ (27%) and 1 time 2+ (5%)]. In the presence of negative bacterial load, we have obtained a high percentage of success in skin graft healing. It looks interesting to deepen the analysis of the wound bed in which those bacteria were present and the skin grafts taken (Figure 4). After the treatment with VERSAJET, 50% of the 50 swabs that were analysed showed a decreased bacterial load, 17% an increased bacterial load and 33% showed no change in bacterial load. These results confirm the data present in medical literature, which support the effectiveness of VERSAJET in drastically reducing the bacterial load (3).

Figure 2.

Correlation between skin grafts taken and type of bacteria present in post‐treatment.

Figure 3.

Correlation between non taken skin grafts and type of bacteria present in post‐treatment.

Figure 4.

Correlation between bacterial load and skin graft taken or not taken.

In the presence of increased bacterial load three skin grafts were taken and one which was not, with unchanged bacterial load five skin grafts were taken and three were not and with decreased bacterial load five skin grafts were taken and seven were not.

After analysing all those data we can assume that reducing the bacterial load is not the only variable which the successful healing of the skin graft depends on.

In conclusion, there is still many data to analyse and study in order to better understand the qualitative and quantitative presence of bacteria and the success of this future surgical procedure.