- Email: [email protected]
Indocyanine green video angiographies help to identify burns requiring operation
Burns 29 (2003) 785–791
Indocyanine green video angiographies help to identify burns requiring operation L.-P. Kamolz a,∗ , H. Andel b , W. Haslik a , A. Donner b , W. Winter b , G. Meissl a , M. Frey a a
Division of Plastic and Reconstructive Surgery, Department of Surgery, Medical School, University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria b Department of Anaesthesia and Intensive Care, Medical School, University of Vienna, Vienna, Austria Accepted 17 June 2003
Abstract The key decision in the treatment of thermal injuries is the determination of the depth of the burn wound and the resultant decision on treatment options. The trend in the treatment of deep dermal and full thickness burns is toward very early excision and grafting to reduce the risk of infection, decrease scar formation, shorten hospital stay, and thereby reducing costs. Traditionally, this has involved serial clinical examinations, which involves primarily subjective judgment. Various objective examination techniques, supplementing the clinical diagnosis, have been suggested, but none has yet achieved widespread clinical acceptance. It has frequently been postulated that the blood flow in injured tissue indicates the extent of tissue damage. In this study, the clinical and scientific impact of indocyanine green (ICG) video angiography was tested in 20 patients. A wide range of depth of injury and etiology was included and analyzed. In all cases considered, video angiography was possible. The measurements and observations correlated well with the actual burn depth, which was assessed clinically (pre- and intraoperative assessment) and histologically (biopsies). In conclusion, ICG video angiography seems to be a practical method to describe vascular patency in a burn wound. The results indicate that ICG fluorescence angiography is a practical, accurate, and effective adjunct to clinical methods for estimating burn wound depth and thereby to assist in the rational assessment of treatment options. Furthermore, it allows an objective, qualitative and quantitative observation of the dynamic changes in burn wound depth, which are observed during the acute post-burn period, thereby indicating optimal timing of the first operation. © 2003 Elsevier Ltd and ISBI. All rights reserved. Keywords: Burns; Depth; Treatment; Fluorescence imaging; Indocyanine green; Video angiography
1. Introduction It is generally accepted that damage to blood vessels in a burn wound consists of three zones [1], each with its own histophysiologic characteristics: a central zone of coagulation necrosis, surrounded by a zone of established edema and capillary stasis, which is in turn surrounded by active edema formation. Watts et al. demonstrated that the vascular patency is a very sensitive indicator of tissue damage [2]. Microvascular damage resulting in stasis and subsequent vessel blockage is one of the most obvious signs of damage in burns. The load of vascular flow through burn injured dermis has been used to monitor the necrosis that occurs in burns [2–5]. A key decision in the treatment of thermal injuries is the initial determination of the depth of injury in the burn wound [1,6]. Traditionally, this has involved serial ∗ Corresponding author. Tel.: +431-40400-6986; fax: +431-40400-6988. E-mail address: [email protected] (L.-P. Kamolz).
0305-4179/$30.00 © 2003 Elsevier Ltd and ISBI. All rights reserved. doi:10.1016/S0305-4179(03)00200-6
clinical examinations, primarily a subjective technique [7,8]. The currently accepted classification of cutaneous burns describes four levels of burn injuries, based on a combination of the clinical estimation of depth and outcome. These are superficial burns, superficial partial thickness burns, deep partial thickness (deep dermal) burns and full thickness burns [9,10]. The trend in the treatment of deep dermal and full thickness burns is toward very early excision and grafting to reduce the risk of infection, decrease scar formation, shorten hospital stay, and reduce costs [11–13]. It is a very common observation in seriously burned patients that areas that appeared to be partial thickness burns at first examination may come to be regarded as full thickness within the next day or days. Various techniques [14–24], supplementing the clinical diagnosis, have been suggested, but none has yet achieved widespread clinical acceptance. The aim of the present study was to evaluate the clinical and scientific utility of indocyanine green video angiography in the investigation of burn wound depth. One of the major goals in the study was to evaluate whether ICG video
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angiography using a commercial system (Pulsion Medical System, Munich, Germany) provided additional benefit for decision making in the treatment of burns.
2. Materials and methods Within the scope of our management regime 20 consecutive patients (mean age 51.3 years, S.D. 11.9 years) admitted to our burn unit for treatment of their burn injuries were imaged and analyzed. Children less than 20 years of age, pregnant women, and patients with a history of allergic reactions were excluded. Each patient was injected intravenously with a single dose of 0.2 mg/kg ICG (ICG-Pulsion® , Pulsion Medical Systems) using either a central venous or a peripheral venous line. The perfusion of burn wounds was measured using the technique of dynamic laser-fluorescence-videography (IC-VIEW® , Pulsion Medical Systems). The entire system, consisting of a digital video camcorder and a near infrared light (NIR-light), is about the size of a conventional camcorder equipped with a video light (Fig. 1). Digital videos were acquired, showing the uptake, steady state distribution, and the clearance of dye-marked blood from the burn area. The perfusion video was viewed in real time and was stored as a digital video file on a notebook for documentation purposes. The ICG-real time videos were interpreted qualitatively and quantitatively according to the staining intensities, reflecting the vascular patency in various areas of the burn wound. The fluorescence intensity of normal, well-perfused tissue (unaffected skin) was used for reference. Skin perfusion was expressed in relation to the reference areas.
For accurate correlation of the fluorescence signal with the respective tissue areas, normal light images were recorded prior to ICG videography using the same digital camcorder. Whereas patients underwent operation, the measurements were correlated with biopsies, which were harvested during the operation.
3. Results Evaluation of skin perfusion by ICG video angiography was possible in all cases admitted over the study period. All patients tolerated the investigations without any reports of nausea, hemodynamic instability, or allergic reactions. Results and images from four of these 20 cases are presented as examples to illustrate the impact of ICG measurements and to demonstrate the interpretation of ICG images and videos. 3.1. Case A Fig. 2 shows the results of ICG video images and measurements for a typical burn wound that was diagnosed clinically as partial thickness at the time of admission. This male patient was 67 years old and suffered from diabetes and cardiac insufficiency. He had facial burns, burns of the left upper extremity, lateral parts of the chest, and abdomen (14% TBSA). 3.1.1. Analysis Fig. 2a shows the burn wound of chest and abdomen immediately after admission (day 0). This wound was
Fig. 1. IC-View® diagnostic apparatus: (a) IC-View® video camera; (b) NIR-light; (c) filter.
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Fig. 2. Burn wound documentation within the first days: (a–d) first row, true color picture; second row, ICG video angiographies (days 0–3: decrease of ICG intensities); third row, false color presentation of the ICG video angiographies; (e) burn wound (day 10), skin grafts.
considered clinically to be of superficial (shallow) partial thickness. The ICG fluorescence images confirmed this assessment. During the first 24 h, a massive progression was noted (Fig. 2b), which was confirmed by the ICG angiogra-
phy on day 1. On day 2 the borderline of the necrotic area was more or less in a steady state, so the operation was planned and performed on the next day (day 3). Meshed skin grafts were applied to all excised areas (Fig 2e).
Fig. 3. Burn wound documentation on day 3 (day of operation): (a) true color picture ((×) central biopsy; (䊊) peripheral biopsy); (b) ICG video angiography; (c) false color presentation of the ICG video angiographies.
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3.2. Case B Fig. 3 shows the results of ICG video images and measurements of a typical burn wound that was diagnosed clinically as full thickness. This female patient was 82 years old, suffered from diabetes and cardiac insufficiency, and was injured while cooking. Her nightdress caught fire resulting in burns of the face, left upper extremity and lateral parts of the chest and abdomen (22% TBSA). 3.2.1. Analysis Fig. 3a shows the burn wound of chest and abdomen 3 days after injury, immediately prior to ICG fluorescence imaging and surgery. This wound was diagnosed clinically to be full thickness burn. The ICG fluorescence images shown in Fig. 3b and c confirmed this assessment. The area was devoid of fluorescence. During surgery, the entire area had
to be excised to viable tissue and fascia. A histological section from the center of the burn wound (Fig. 3a) revealed coagulation necrosis of the dermis, with focal involvement of subcutaneous fat. The section from the outer parts of the burn wound revealed a more or less complete necrosis of epidermis and dermis; only very small parts of dermis were partly intact in this region. Meshed skin grafts were applied to all excised areas. The patient died 10 days after the operation. 3.3. Case C Fig. 4 shows results of ICG video images and measurements for a typical burn representing a mixture of all kinds of burn depth. This male patient was 50 years old, injured while working. He was kneeling on a special mix of hot cement, resulting in burns to both knees (2% TBSA).
Fig. 4. Burn wound documentation on day 7 (day of operation): (a/a ) true color picture; (b/b ) ICG video angiography; (c/c ) false color presentation of the ICG video angiographies; (d/d ) burn wound on day 17 (d: conservative, keratinocytes and skin grafts; d : conservative, keratinocytes).
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Fig. 5. Burn wound documentation on day 3 (day of operation): (a) true color picture; (b) ICG video angiography; (c) false color presentation of the ICG video angiographies; (d) burn wound on day 10 (conservative, keratinocytes).
3.3.1. Analysis Fig. 4a and a shows the burn wound of both knees 7 days after injury, immediately prior to ICG fluorescence imaging and surgery. This burn was judged clinically to be a mixture of injuries of various depths. The ICC fluorescence images, shown in Fig. 4b and b , are in accordance with this assessment. The relatively high homogenous intensity in some areas indicated that they were superficial partial thickness burns. Some areas showed lower ICG intensities or only a discrete nature of ICG fluorescence indicating deep partial thickness burn areas. Moreover, full thickness burned regions without any fluorescence were also observed. One histological section revealed coagulation necrosis of the dermis, with focal involvement of subcutaneous fat, in the other section a deep dermal partial thickness burn with complete necrosis of epidermis and partial intact dermis was found (Fig. 4a and a ). The superficial burn areas were not operated upon, deeper parts were tangentially excised and keratinocytes were applied. The full thickness burned area was excised to the fascia and meshed split thickness grafts were applied (Fig. 4d and d ). 3.4. Case D Fig. 5 shows the results of ICG video images and measurements of a clinically diagnosed superficial burn injury. This male patient was 28 years old, injured while working as a fire-eater in a circus, suffering from burns localized to the face, neck and chest (11% TBSA).
ficial partial thickness. The ICG fluorescence images shown in Fig. 5b and c confirmed this assessment. The high homogenous fluorescence intensity indicated a superficial partial thickness burn injury. Central parts were less intensively, but also homogeneously, stained by ICG. After acquiring the ICG video, the chest was debrided by scraping. Punctuate bleeding was obtained confirming depth assessment as superficial partial thickness. The central parts were tangentially debrided and grafted with keratinocytes. As expected, the burn wound healed, well (Fig. 5d taken on day 15). 3.4.2. Results derived from all 20 patients Superficial partial thickness burns are characterized by areas of relatively bright and homogenous fluorescence, quick uptake, constant and high steady state distribution and quick clearance, indicating patency of the small vessels of the sub-papillary and dermal plexus. Those kinds of burns do not require any operative procedure. Deep dermal partial thickness burns, which should be operated on as early as possible, appear as darker areas yielding mottled fluorescence, with slower uptake, constant but less steady state distribution, indicating partial patency of the dermal plexus. Full thickness burns, which also require surgical intervention and skin grafts, are areas showing only large and discrete vessels or no signs of fluorescence otherwise, indicating little or no remaining blood flow in the dermis.
4. Discussion 3.4.1. Analysis Fig. 5a shows the burn wound of neck and chest 3 days after injury, immediately prior to ICG fluorescence imaging and surgery. This burn was considered clinically to be super-
One of the major problems that faces any burn surgeon, is the decision on the nature of treatment (conservative treatment versus operative treatment). In the case of an operative
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procedure a decision is needed on when to excise the burn wounds and to determine accurately the depth of the lesion and thereby the extent of tissue involvement [1,6–8]. The trend in the treatment of deep dermal partial thickness and full thickness burns leans toward very early excision and grafting in order to reduce the risk of infection, decrease scar formation, shorten hospital stay, and reduce costs [11,13]. However, initial clinical assessment of burn depth is often unreliable and may require several days for an accurate evaluation. It is a very common observation in burned patients that areas appearing to be partial thickness burns come to be regarded as full thickness within the next day or days. Thermal trauma causes two different types of injuries within the burn wound. First an immediate and irreversible injury, and second a delayed and potential reversible injury in the area bordering the center site, which is called the zone of stasis [25]. In the past, techniques for evaluating burn depth and its progression were limited, consisting mainly of subjective clinical examinations. Several adjuncture imaging techniques, to assist in determining burn depth, have been described and published. These methods have included both, invasive and non-invasive techniques [14–24]. Invasive techniques have a major disadvantage, because they may inflict an additional injury to the burned areas due to an increased risk of secondary infections. These problems may be avoided by non-invasive techniques such as skin-surface-temperature measurements, infrared thermography [16,17], laser-doppler imaging [18–20] and ICG fluorescence angiography [21–24], but none of these methods has achieved widespread acceptance. The major disadvantage of many of these methods is the inability to correlate structure with function. Therefore, lacking appropriate methods for accurate location identification, studies of dynamic phenomena such as vasoconstriction and dilatation, changes in blood flow distribution, thromboembolism, and microcirculatory standstill in the burn wound have been inconclusive. Although animal models of thermal trauma have provided additional data on microcirculatory changes, many questions still remain unanswered [5]. ICG video angiography seems not only to be capable of describing burn depth; but also to allow an objective decision how to treat burn wounds in relation to the analysis of vascular patency. These findings and postulations are supported by the findings of Watts et al. [2], who demonstrated that vascular patency is a very sensitive indicator of tissue damage. Microvascular damage, which results in stasis and subsequent vessel blockage, is one of the most obvious signs of damage in burns [3]. It is our contention that ICG is also able to differentiate regions showing different perfusion wounds and thereby helps to plan operations with all various options (skin grafts, keratinocytes). Moreover, our results indicate that ICG fluorescence video angiography is an objective method for the observation of dynamic changes in burn wound perfusion. These findings are analogous to
those of Boushel et al. [26], who found that ICG is capable of determining the regional blood flow distribution and regulation during exercise. This real time video angiography is superior to ICG images, used in former studies [21–24], as the evaluation of ICG uptake, steady state distribution, and clearance of dye-marked blood from the burn area in combination with the clinical assessment provides additional information for the interpretation of the damage to burned skin and in the description of its vascular patency. Our results and observations met the expectations of Still et al. [24], who stated, that an analysis, which is independent of the judgment of with experienced burn surgeon, would be very useful. This method seems to be capable of indicating how and when to treat burn wounds. Additionally, it might have the capability to assess the impact of different therapeutic strategies on burn wound perfusion and its progression within the scope of treatment methodology and objectives. In conclusion, the results suggest that ICG fluorescence video angiography is a practical, accurate, and effective adjunct to clinical methods for determining burn depth and burn wound progression. Moreover, it can assist when an objective decision on how and when to treat burn patients is required.
References [1] Jackson DM. The diagnosis of the depth of burning. Br J Surg 1953;40:588–96. [2] Watts AMI, Tyler MPH, Perry ME, Roberts AHN, McGrouther DA. Burn depth and its histological measurement. Burns 2001;27(2): 154–60. [3] Sevit S. Local blood-flow changes in experimental burns. J Pathol Bacteriol 1949;61:427–42. [4] Zawacki BE. Reversal of capillary stasis and prevention of necrosis in burns. Ann Surg 1974;180:98–102. [5] Boykin JV, Eriksson E, Pittman RN. In vivo microcirculation of a scald burn and the progression of postburn dermal ischemia. Plast Reconstr Surg 1980;66:191–8. [6] Heimbach D, Engrav L, Grube B, Marvin J. Burn depth: a review. World J Surg 1992;16(1):10–5. [7] Hlava P, Moserova J, Konigova R. Validity of clinical assessment of the depth of a thermal injury. Acta Chir Plast 1983;25(4):202–8. [8] Godina M, Derganc M, Brcic A. The reliability of clinical assessment of the depth of burns. Burns 1977;4(2):92–6. [9] Muir IKF, Barclay TL. Burns and their treatment. London: Lloyd Luke; 1962. [10] Boswick JA. The art and science of burn care. Rockville: Aspen; 1987. [11] Engrav LH, Heimbach DM, Reus JL, Harnar TJ, Marvin JA. Early excision and grafting vs. nonoperative treatment of burns of indeterminant depth: a randomized prospective study. J Trauma 1983;23(11):1001–4. [12] Spurr ED, Shakespeare PG. Incidence of hypertrophic scarring in burned-children. Burns 1990;16(3):179–81. [13] Still JM, Law EJ, Belcher K, Thiruvaiyarv D. Decreased length of hospital stay by early excision and grafting of burns. South Med J 1996;89:578–82. [14] Shakespeare PG. Looking at burn wounds: the A.B. Wallace Memorial Lecture 1991. Burns 1992;18(4):287–95.
L.-P. Kamolz et al. / Burns 29 (2003) 785–791 [15] Shakespeare PG. Burn wound healing and skin substitutes. Burns 2001;27(5):517–22. [16] Cole RP, Shakespeare PG, Chissell HG, Jones SG. Thermographic assessment of burns using a nonpermeable membrane as wound covering. Burns 1991;17(2):117–22. [17] Wyllie FJ, Sutherland AB. Measurement of surface temperature as an aid to the diagnosis of burn depth. Burns 1991;17(2):123–7. [18] Kloppenberg FW, Beerthuizen GI, ten Duis HJ. Perfusion of burn wounds assessed by laser doppler imaging is related to burn depth and healing time. Burns 2001;27(4):359–63. [19] Droog EJ, Steenbergen W, Sjoberg F. Measurement of depth of burns by laser doppler perfusion imaging. Burns 2001;27(6):561–8. [20] Holland AJA, Martin HCO, Cass DT. Laser doppler imaging prediction of burn wound outcome in children. Burns 2002;28(1): 11–7. [21] Sheridan RL, Schomaker KT, Lucchina LC, Hurley J, Yin LM, Tompkins RG, et al. Burn depth estimation by use of indocyanine
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green fluorescence: initial human trial. J Burn Care Rehabil 1995;16(6):602–4. Green HA, Bua D, Anderson RR, Nishioka NS. Burn depth estimation using indocyanine green fluorescence. Arch Dermatol 1992;128(1):43–9. Jerath MR, Schomacker KT, Sheridan RL, Nishioka NS. Bum wound assessment in porcine skin using indocyanine green fluorescence. J Trauma 1999;46(6):1085–8. Still JM, Law EJ, Klavuhn KG, Island TC, Holtz JZ. Diagnosis of burn depth using laser-induced indocyanine green fluorescence: a preliminary clinical trial. Burns 2001;27(4):364–71. Zawacki BE. The natural history of reversible burn injury. Surg Gynecol Obstet 1974;139:867–72. Boushel R, Langberg H, Olesen J, Nowak M, Simonsen L, Bülow J, et al. Regional blood flow during exercise in humans measured by near-infrared spectroscopy and indocyanine green. J Appl Physiol 2000;89:1868–78.
Indocyanine green video angiographies help to identify burns requiring operation L.-P. Kamolz a,∗ , H. Andel b , W. Haslik a , A. Donner b , W. Winter b , G. Meissl a , M. Frey a a
Division of Plastic and Reconstructive Surgery, Department of Surgery, Medical School, University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria b Department of Anaesthesia and Intensive Care, Medical School, University of Vienna, Vienna, Austria Accepted 17 June 2003
Abstract The key decision in the treatment of thermal injuries is the determination of the depth of the burn wound and the resultant decision on treatment options. The trend in the treatment of deep dermal and full thickness burns is toward very early excision and grafting to reduce the risk of infection, decrease scar formation, shorten hospital stay, and thereby reducing costs. Traditionally, this has involved serial clinical examinations, which involves primarily subjective judgment. Various objective examination techniques, supplementing the clinical diagnosis, have been suggested, but none has yet achieved widespread clinical acceptance. It has frequently been postulated that the blood flow in injured tissue indicates the extent of tissue damage. In this study, the clinical and scientific impact of indocyanine green (ICG) video angiography was tested in 20 patients. A wide range of depth of injury and etiology was included and analyzed. In all cases considered, video angiography was possible. The measurements and observations correlated well with the actual burn depth, which was assessed clinically (pre- and intraoperative assessment) and histologically (biopsies). In conclusion, ICG video angiography seems to be a practical method to describe vascular patency in a burn wound. The results indicate that ICG fluorescence angiography is a practical, accurate, and effective adjunct to clinical methods for estimating burn wound depth and thereby to assist in the rational assessment of treatment options. Furthermore, it allows an objective, qualitative and quantitative observation of the dynamic changes in burn wound depth, which are observed during the acute post-burn period, thereby indicating optimal timing of the first operation. © 2003 Elsevier Ltd and ISBI. All rights reserved. Keywords: Burns; Depth; Treatment; Fluorescence imaging; Indocyanine green; Video angiography
1. Introduction It is generally accepted that damage to blood vessels in a burn wound consists of three zones [1], each with its own histophysiologic characteristics: a central zone of coagulation necrosis, surrounded by a zone of established edema and capillary stasis, which is in turn surrounded by active edema formation. Watts et al. demonstrated that the vascular patency is a very sensitive indicator of tissue damage [2]. Microvascular damage resulting in stasis and subsequent vessel blockage is one of the most obvious signs of damage in burns. The load of vascular flow through burn injured dermis has been used to monitor the necrosis that occurs in burns [2–5]. A key decision in the treatment of thermal injuries is the initial determination of the depth of injury in the burn wound [1,6]. Traditionally, this has involved serial ∗ Corresponding author. Tel.: +431-40400-6986; fax: +431-40400-6988. E-mail address: [email protected] (L.-P. Kamolz).
0305-4179/$30.00 © 2003 Elsevier Ltd and ISBI. All rights reserved. doi:10.1016/S0305-4179(03)00200-6
clinical examinations, primarily a subjective technique [7,8]. The currently accepted classification of cutaneous burns describes four levels of burn injuries, based on a combination of the clinical estimation of depth and outcome. These are superficial burns, superficial partial thickness burns, deep partial thickness (deep dermal) burns and full thickness burns [9,10]. The trend in the treatment of deep dermal and full thickness burns is toward very early excision and grafting to reduce the risk of infection, decrease scar formation, shorten hospital stay, and reduce costs [11–13]. It is a very common observation in seriously burned patients that areas that appeared to be partial thickness burns at first examination may come to be regarded as full thickness within the next day or days. Various techniques [14–24], supplementing the clinical diagnosis, have been suggested, but none has yet achieved widespread clinical acceptance. The aim of the present study was to evaluate the clinical and scientific utility of indocyanine green video angiography in the investigation of burn wound depth. One of the major goals in the study was to evaluate whether ICG video
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angiography using a commercial system (Pulsion Medical System, Munich, Germany) provided additional benefit for decision making in the treatment of burns.
2. Materials and methods Within the scope of our management regime 20 consecutive patients (mean age 51.3 years, S.D. 11.9 years) admitted to our burn unit for treatment of their burn injuries were imaged and analyzed. Children less than 20 years of age, pregnant women, and patients with a history of allergic reactions were excluded. Each patient was injected intravenously with a single dose of 0.2 mg/kg ICG (ICG-Pulsion® , Pulsion Medical Systems) using either a central venous or a peripheral venous line. The perfusion of burn wounds was measured using the technique of dynamic laser-fluorescence-videography (IC-VIEW® , Pulsion Medical Systems). The entire system, consisting of a digital video camcorder and a near infrared light (NIR-light), is about the size of a conventional camcorder equipped with a video light (Fig. 1). Digital videos were acquired, showing the uptake, steady state distribution, and the clearance of dye-marked blood from the burn area. The perfusion video was viewed in real time and was stored as a digital video file on a notebook for documentation purposes. The ICG-real time videos were interpreted qualitatively and quantitatively according to the staining intensities, reflecting the vascular patency in various areas of the burn wound. The fluorescence intensity of normal, well-perfused tissue (unaffected skin) was used for reference. Skin perfusion was expressed in relation to the reference areas.
For accurate correlation of the fluorescence signal with the respective tissue areas, normal light images were recorded prior to ICG videography using the same digital camcorder. Whereas patients underwent operation, the measurements were correlated with biopsies, which were harvested during the operation.
3. Results Evaluation of skin perfusion by ICG video angiography was possible in all cases admitted over the study period. All patients tolerated the investigations without any reports of nausea, hemodynamic instability, or allergic reactions. Results and images from four of these 20 cases are presented as examples to illustrate the impact of ICG measurements and to demonstrate the interpretation of ICG images and videos. 3.1. Case A Fig. 2 shows the results of ICG video images and measurements for a typical burn wound that was diagnosed clinically as partial thickness at the time of admission. This male patient was 67 years old and suffered from diabetes and cardiac insufficiency. He had facial burns, burns of the left upper extremity, lateral parts of the chest, and abdomen (14% TBSA). 3.1.1. Analysis Fig. 2a shows the burn wound of chest and abdomen immediately after admission (day 0). This wound was
Fig. 1. IC-View® diagnostic apparatus: (a) IC-View® video camera; (b) NIR-light; (c) filter.
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Fig. 2. Burn wound documentation within the first days: (a–d) first row, true color picture; second row, ICG video angiographies (days 0–3: decrease of ICG intensities); third row, false color presentation of the ICG video angiographies; (e) burn wound (day 10), skin grafts.
considered clinically to be of superficial (shallow) partial thickness. The ICG fluorescence images confirmed this assessment. During the first 24 h, a massive progression was noted (Fig. 2b), which was confirmed by the ICG angiogra-
phy on day 1. On day 2 the borderline of the necrotic area was more or less in a steady state, so the operation was planned and performed on the next day (day 3). Meshed skin grafts were applied to all excised areas (Fig 2e).
Fig. 3. Burn wound documentation on day 3 (day of operation): (a) true color picture ((×) central biopsy; (䊊) peripheral biopsy); (b) ICG video angiography; (c) false color presentation of the ICG video angiographies.
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3.2. Case B Fig. 3 shows the results of ICG video images and measurements of a typical burn wound that was diagnosed clinically as full thickness. This female patient was 82 years old, suffered from diabetes and cardiac insufficiency, and was injured while cooking. Her nightdress caught fire resulting in burns of the face, left upper extremity and lateral parts of the chest and abdomen (22% TBSA). 3.2.1. Analysis Fig. 3a shows the burn wound of chest and abdomen 3 days after injury, immediately prior to ICG fluorescence imaging and surgery. This wound was diagnosed clinically to be full thickness burn. The ICG fluorescence images shown in Fig. 3b and c confirmed this assessment. The area was devoid of fluorescence. During surgery, the entire area had
to be excised to viable tissue and fascia. A histological section from the center of the burn wound (Fig. 3a) revealed coagulation necrosis of the dermis, with focal involvement of subcutaneous fat. The section from the outer parts of the burn wound revealed a more or less complete necrosis of epidermis and dermis; only very small parts of dermis were partly intact in this region. Meshed skin grafts were applied to all excised areas. The patient died 10 days after the operation. 3.3. Case C Fig. 4 shows results of ICG video images and measurements for a typical burn representing a mixture of all kinds of burn depth. This male patient was 50 years old, injured while working. He was kneeling on a special mix of hot cement, resulting in burns to both knees (2% TBSA).
Fig. 4. Burn wound documentation on day 7 (day of operation): (a/a ) true color picture; (b/b ) ICG video angiography; (c/c ) false color presentation of the ICG video angiographies; (d/d ) burn wound on day 17 (d: conservative, keratinocytes and skin grafts; d : conservative, keratinocytes).
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Fig. 5. Burn wound documentation on day 3 (day of operation): (a) true color picture; (b) ICG video angiography; (c) false color presentation of the ICG video angiographies; (d) burn wound on day 10 (conservative, keratinocytes).
3.3.1. Analysis Fig. 4a and a shows the burn wound of both knees 7 days after injury, immediately prior to ICG fluorescence imaging and surgery. This burn was judged clinically to be a mixture of injuries of various depths. The ICC fluorescence images, shown in Fig. 4b and b , are in accordance with this assessment. The relatively high homogenous intensity in some areas indicated that they were superficial partial thickness burns. Some areas showed lower ICG intensities or only a discrete nature of ICG fluorescence indicating deep partial thickness burn areas. Moreover, full thickness burned regions without any fluorescence were also observed. One histological section revealed coagulation necrosis of the dermis, with focal involvement of subcutaneous fat, in the other section a deep dermal partial thickness burn with complete necrosis of epidermis and partial intact dermis was found (Fig. 4a and a ). The superficial burn areas were not operated upon, deeper parts were tangentially excised and keratinocytes were applied. The full thickness burned area was excised to the fascia and meshed split thickness grafts were applied (Fig. 4d and d ). 3.4. Case D Fig. 5 shows the results of ICG video images and measurements of a clinically diagnosed superficial burn injury. This male patient was 28 years old, injured while working as a fire-eater in a circus, suffering from burns localized to the face, neck and chest (11% TBSA).
ficial partial thickness. The ICG fluorescence images shown in Fig. 5b and c confirmed this assessment. The high homogenous fluorescence intensity indicated a superficial partial thickness burn injury. Central parts were less intensively, but also homogeneously, stained by ICG. After acquiring the ICG video, the chest was debrided by scraping. Punctuate bleeding was obtained confirming depth assessment as superficial partial thickness. The central parts were tangentially debrided and grafted with keratinocytes. As expected, the burn wound healed, well (Fig. 5d taken on day 15). 3.4.2. Results derived from all 20 patients Superficial partial thickness burns are characterized by areas of relatively bright and homogenous fluorescence, quick uptake, constant and high steady state distribution and quick clearance, indicating patency of the small vessels of the sub-papillary and dermal plexus. Those kinds of burns do not require any operative procedure. Deep dermal partial thickness burns, which should be operated on as early as possible, appear as darker areas yielding mottled fluorescence, with slower uptake, constant but less steady state distribution, indicating partial patency of the dermal plexus. Full thickness burns, which also require surgical intervention and skin grafts, are areas showing only large and discrete vessels or no signs of fluorescence otherwise, indicating little or no remaining blood flow in the dermis.
4. Discussion 3.4.1. Analysis Fig. 5a shows the burn wound of neck and chest 3 days after injury, immediately prior to ICG fluorescence imaging and surgery. This burn was considered clinically to be super-
One of the major problems that faces any burn surgeon, is the decision on the nature of treatment (conservative treatment versus operative treatment). In the case of an operative
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procedure a decision is needed on when to excise the burn wounds and to determine accurately the depth of the lesion and thereby the extent of tissue involvement [1,6–8]. The trend in the treatment of deep dermal partial thickness and full thickness burns leans toward very early excision and grafting in order to reduce the risk of infection, decrease scar formation, shorten hospital stay, and reduce costs [11,13]. However, initial clinical assessment of burn depth is often unreliable and may require several days for an accurate evaluation. It is a very common observation in burned patients that areas appearing to be partial thickness burns come to be regarded as full thickness within the next day or days. Thermal trauma causes two different types of injuries within the burn wound. First an immediate and irreversible injury, and second a delayed and potential reversible injury in the area bordering the center site, which is called the zone of stasis [25]. In the past, techniques for evaluating burn depth and its progression were limited, consisting mainly of subjective clinical examinations. Several adjuncture imaging techniques, to assist in determining burn depth, have been described and published. These methods have included both, invasive and non-invasive techniques [14–24]. Invasive techniques have a major disadvantage, because they may inflict an additional injury to the burned areas due to an increased risk of secondary infections. These problems may be avoided by non-invasive techniques such as skin-surface-temperature measurements, infrared thermography [16,17], laser-doppler imaging [18–20] and ICG fluorescence angiography [21–24], but none of these methods has achieved widespread acceptance. The major disadvantage of many of these methods is the inability to correlate structure with function. Therefore, lacking appropriate methods for accurate location identification, studies of dynamic phenomena such as vasoconstriction and dilatation, changes in blood flow distribution, thromboembolism, and microcirculatory standstill in the burn wound have been inconclusive. Although animal models of thermal trauma have provided additional data on microcirculatory changes, many questions still remain unanswered [5]. ICG video angiography seems not only to be capable of describing burn depth; but also to allow an objective decision how to treat burn wounds in relation to the analysis of vascular patency. These findings and postulations are supported by the findings of Watts et al. [2], who demonstrated that vascular patency is a very sensitive indicator of tissue damage. Microvascular damage, which results in stasis and subsequent vessel blockage, is one of the most obvious signs of damage in burns [3]. It is our contention that ICG is also able to differentiate regions showing different perfusion wounds and thereby helps to plan operations with all various options (skin grafts, keratinocytes). Moreover, our results indicate that ICG fluorescence video angiography is an objective method for the observation of dynamic changes in burn wound perfusion. These findings are analogous to
those of Boushel et al. [26], who found that ICG is capable of determining the regional blood flow distribution and regulation during exercise. This real time video angiography is superior to ICG images, used in former studies [21–24], as the evaluation of ICG uptake, steady state distribution, and clearance of dye-marked blood from the burn area in combination with the clinical assessment provides additional information for the interpretation of the damage to burned skin and in the description of its vascular patency. Our results and observations met the expectations of Still et al. [24], who stated, that an analysis, which is independent of the judgment of with experienced burn surgeon, would be very useful. This method seems to be capable of indicating how and when to treat burn wounds. Additionally, it might have the capability to assess the impact of different therapeutic strategies on burn wound perfusion and its progression within the scope of treatment methodology and objectives. In conclusion, the results suggest that ICG fluorescence video angiography is a practical, accurate, and effective adjunct to clinical methods for determining burn depth and burn wound progression. Moreover, it can assist when an objective decision on how and when to treat burn patients is required.
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