Current Issue

The online formats of SRGS include access to What You Should Know (WYSK): commentaries on articles published recently in top medical journals. These commentaries, written by practicing surgeons and other medical experts, focus on the strengths and weaknesses of the research, as well as on the articles' contributions in advancing the field of surgery.

Below is a sample of one of the commentaries published in the current edition of WYSK.

Citation of Articles Reviewed:

Zajac JC, Liu A, Uselmann AJ, et al. Lighting the Way for Necrosis Excision Through Indocyanine Green Fluorescence-Guided Surgery. J Am Coll Surg. 2022;235(5):743-755. doi:10.1097/XCS.0000000000000329

Commentary by: Marc Gorvet, DO, FACS; and Paul Glat, MD, FACS

The timely and proper diagnosis of the depth of a burn has broad implications, including indications for surgery, healing potential, fluid resuscitation, morbidity, and even mortality. Clinical judgment is the most frequently used technique, but even the most experienced burn surgeons have only 60-75% accuracy.¹ There have been multiple technological advances for determining burn depth, including biopsy with histologic assessment (gold standard), thermography, indocyanine green (ICG) fluorescence dye, laser Doppler imaging (LDI), and others.¹ However, none of these have reached widespread use amongst the burn community, mostly due to cost, time, and slow rates of adoption in experienced burn units. This can lead to over-excision of viable tissues or unnecessary surgical intervention, increased area of donor harvest, and subsequent increase in scar burden with its potential for associated complications (i.e., contracture, hypertrophy, aesthetics, etc.). Zajac et al. investigated the use of second window indocyanine green (SWIG) to utilize novel technology to assess burn wound depth and hopefully decrease the surgical burden. SWIG has previously been described for use in oncologic surgery as a newer modality to aid in the intraoperative identification of the extent of tumor burden.^2,3

This pilot article aims to evaluate and compare SWIG with indocyanine green angiography (ICGA) to determine burn wound depth in three study models: human patients, mice, and human xenograft. The human patient arm consisted of 12 deep partial and full thickness burns in 7 patients. Seven of the wounds were assessed with ICGA and two with SWIG. Wounds were assessed at baseline using brightfield and near-infrared (NIR) fluorescence, with ICGA following FDA-approved dosing of ICG, then with SWIG 24 hours after injection of the remaining ICG (using both SPY-Elite (SPY; Stryker/Novadaq, British Columbia, Canada) and OnLume Imaging System (OIS; OnLume Surgical, Madison, WI) technology [secondary study comparison]). A full-thickness biopsy with hematoxylin and eosin (H&E) and lactate dehydrogenase (LDH) staining of the region of interest (ROI) was taken for gold-standard assessment of burn depth. ICGA and SWIG were recorded based on the degree of fluorescence. In the mouse and human xenograft arms, burn wounds were created using a standard technique and studied with ICG injection at different concentrations (1, 2, and 5 mg/kg) and administered at different time intervals from the time of burn (immediate, 3 hours, 24 hours). The wounds were assessed with SWIG and ICGA with subsequent full-thickness biopsy and microscopic assessment.

The findings in the study showed that current ICGA methods were inconsistent and unable to be standardized. The results showed inter-patient variations independent of ICG dose and timing of injection after injury. Secondarily, ICGA inaccurately diagnosed burn depth in multiple areas, determining they were superficial despite histology showing them to be deep, partial, and full thickness. Both ICGA and SWIG showed signal-to-background ratios (SBRs) that were found to be higher when injected with the 5 mg/kg dose and significantly higher when injected immediately after injury rather than 3 or 24 hours post-injury.

Necrosis was associated with SWIG fluorescence in human burn patients. There was fluorescence retention with SWIG imaging 24 hours after ICG injection in grossly necrotic regions. This result was further exemplified by SWIG fluorescence pre-excision and absent post-excision with a lack of SWIG in the adjacent non-burned tissues. The burn depth was confirmed with a biopsy and LDH staining. LDH staining was also used in mouse models to confirm microscopic SWIG fluorescence. ICG fluorescence was noted to be strongest within necrotic epithelial-lined structures of both mouse and human xenograft models.

A strength of the study is that it further proves the shortcomings of ICGA. Current literature has been promising for its use; however, its results are difficult to replicate and, without a standardized approach, difficult to implement.^4,5 The limitations of this study stem from its small sample size.

In conclusion, the study shows SWIG has an interesting potential for future clinical application and needs further evaluation. The authors propose a novel approach to standardizing burn depth assessment while beginning to protocolize the most effective dose and timing of ICG administration for the most accurate evaluation. This may lead to a simple, cost-effective, and safe method to determine burn wound depth.

References

1. Monstrey S, Hoeksema H, Verbelen J, Pirayesh A, Blondeel P. Assessment of burn depth and burn wound healing potential. Burns. 2008;34(6):761-769. doi:10.1016/j.burns.2008.01.009
2. Teng CW, Cho SS, Singh Y, et al. Second window ICG predicts gross-total resection and progression-free survival during brain metastasis surgery. J Neurosurg. 2021;135(4):1026-1035. Published 2021 Mar 2. doi:10.3171/2020.8.JNS201810
3. Newton AD, Predina JD, Corbett CJ, et al. Optimization of Second Window Indocyanine Green for Intraoperative Near-Infrared Imaging of Thoracic Malignancy. J Am Coll Surg. 2019;228(2):188-197. doi:10.1016/j.jamcollsurg.2018.11.003
4. Wongkietkachorn A, Surakunprapha P, Winaikosol K, et al. Indocyanine green dye angiography as an adjunct to assess indeterminate burn wounds: A prospective, multicentered, triple-blinded study. J Trauma Acute Care Surg. 2019;86(5):823-828. doi:10.1097/TA.0000000000002179
5. McUmber H, Dabek RJ, Bojovic B, Driscoll DN. Burn Depth Analysis Using Indocyanine Green Fluorescence: A Review. J Burn Care Res. 2019;40(4):513-516. doi:10.1093/jbcr/irz054

The SRGS Recommended Reading List is a summary of the most pertinent articles cited in each issue; the editor has carefully selected a group of current, classic, and seminal articles for further study in certain formats of SRGS. The citations below are linked to their abstracts on PubMed, and free full texts are available where indicated.

SRGS has obtained permission from journal publishers to reprint these articles. Copying and distributing these reprints is a violation of our licensing agreement with these publishers and is strictly prohibited.

Long DR, Alverdy JC, Vavilala MS. Emerging Paradigms in the Prevention of Surgical Site Infection: The Patient Microbiome and Antimicrobial Resistance. Anesthesiology. 2022;137(2):252-262. doi:10.1097/ALN.0000000000004267

This article provided an expert commentary on the role of the patient microbiome as a contributor to surgical site infection. The authors provided valuable information regarding factors that disrupt the microbiome, events that alter the pathways for the translocation of organisms, and interventions for correcting microbiome disruptions.

Haydour Q, Hage CA, Carmona EM, et al. Diagnosis of Fungal Infections. A Systematic Review and Meta-Analysis Supporting American Thoracic Society Practice Guideline. Ann Am Thorac Soc. 2019;16(9):1179-1188. doi:10.1513/AnnalsATS.201811-766OC

The authors provided evidence supporting a recognized national clinical practice guideline. Diagnostic tests for fungal infections, guidance for the duration of anti-fungal therapy, and characteristics of various surgical infections caused by fungi are reviewed.

Bellon F, Solà I, Gimenez-Perez G, et al. Perioperative glycaemic control for people with diabetes undergoing surgery. Cochrane Database Syst Rev. 2023;8(8):CD007315. Published 2023 Aug 1. doi:10.1002/14651858.CD007315.pub3

A valuable review of evidence regarding perioperative glycemic control for patients with diabetes who must undergo an operative procedure is provided in this article.