Near-Infrared Fluorescence with Indocyanine Green to Assess Bone Perfusion: A Systematic Review

What is the diagnostic accuracy of fluorescence-guided surgery for margin assessment in appendicular bone and soft tissue tumors? - A systematic review of clinical studies

BACKGROUND

Fluorescence-guided surgery (FGS) is a novel technique to successfully assess surgical margins intraoperatively. Investigation and adoption of this technique in orthopaedic oncology remains limited.

METHODS

The PRISMA guidelines were followed for this manuscript. Our study was registered on PROSPERO (380520). Studies describing the use of FGS for resection of bone and soft tissue sarcomas (STS) on humans were included. Diagnostic performance metrics (sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV] and accuracy) and margin positivity rate were the outcomes assessed.

RESULTS

Critical appraisal using the Joanna Brigs Institute checklists showed significant concerns for study quality. Sensitivity of FGS ranged from 22.2 % to 100 % in three of the four studies assessing his metrics; one study in appendicular tumors in the pediatric population reported 0 % sensitivity in the three cases included. Specificity ranged from 9.38 % to 100 %. PPV ranged from 14.6 % to 70 % while NPV was between 53.3 % and 100 %. The diagnostic accuracy ranged from 21.62 % to 92.31 %. Margin positivity rate ranged from 2 % to 50 %, with six of the seven studies reporting values between 20 % and 50 %.

CONCLUSIONS

FSG is a feasible technique to assess tumor margins in bone and STS. Reported performance metrics and margin positivity rates vary widely between studies due to low study quality and high heterogeneity in dying protocols.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Application of indocyanine green in surgery: A review of current evidence and implementation in trauma patients

Background: Modern surgical medicine strives to manage trauma while improving outcomes using functional imaging. Identification of viable tissues is crucial for the surgical management of polytrauma and burn patients presenting with soft tissue and hollow viscus injuries. Bowel anastomosis after trauma-related resection is associated with a high rate of leakage. The ability of the surgeon’s bare eye to determine bowel viability remains limited, and the need for a more standardized objective assessment has not yet been fulfilled. Hence, there is a need for more precise diagnostic tools to enhance surgical evaluation and visualization to aid early diagnosis and timely management to minimize trauma-associated complications. Indocyanine green (ICG) coupled with fluorescence angiography is a potential solution for this problem. ICG is a fluorescent dye that responds to near-infrared irradiation. Methods: We conducted a narrative review to address the utility of ICG in the surgical management of patients with trauma as well as elective surgery. Discussion: ICG has many applications in different medical fields and has recently become an important clinical indicator for surgical guidance. However, there is a paucity of information regarding the use of this technology to treat traumas. Recently, angiography with ICG has been introduced in clinical practice to visualize and quantify organ perfusion under several conditions, leading to fewer cases of anastomotic insufficiency. This has great potential to bridge this gap and enhance the clinical outcomes of surgery and patient safety. However, there is no consensus on the ideal dose, time, and manner of administration nor the indications that ICG provides a genuine advantage through greater safety in trauma surgical settings. Conclusions: There is a scarcity of publications describing the use of ICG in trauma patients as a potentially useful strategy to facilitate intraoperative decisions and to limit the extent of surgical resection. This review will improve our understanding of the utility of intraoperative ICG fluorescence in guiding and assisting trauma surgeons to deal with the intraoperative challenges and thus improve the patients’ operative care and safety in the field of trauma surgery.

Spatial and temporal patterns in dynamic-contrast enhanced intraoperative fluorescence imaging enable classification of bone perfusion in patients undergoing leg amputation

Dynamic contrast-enhanced fluorescence imaging (DCE-FI) classification of tissue viability in twelve adult patients undergoing below knee leg amputation is presented. During amputation and with the distal bone exposed, indocyanine green contrast-enhanced images were acquired sequentially during baseline, following transverse osteotomy and following periosteal stripping, offering a uniquely well-controlled fluorescence dataset. An unsupervised classification machine leveraging 21 different spatiotemporal features was trained and evaluated by cross-validation in 3.5 million regions-of-interest obtained from 9 patients, demonstrating accurate stratification into normal, suspicious, and compromised regions. The machine learning (ML) approach also outperformed the standard method of using fluorescence intensity only to evaluate tissue perfusion by a two-fold increase in accuracy. The generalizability of the machine was evaluated in image series acquired in an additional three patients, confirming the stability of the model and ability to sort future patient image-sets into viability categories.