Impact of Surgical Lights on the Performance of Fluorescence-Guided Surgery Systems: A Pilot Study

Fluorescence-guided surgery can aid in the intraoperative visualization of target tissues, with promising applications in human and veterinary surgical oncology. The aim of this study was to evaluate the performances of two fluoresce camera systems, IC-FlowTM and VisionsenseTM VS3 Iridum, for the detection of two non-targeted (ICG and IRDye-800) and two targeted fluorophores (AngiostampTM and FAP-Cyan) under different room light conditions, including ambient light, new generation LED, and halogen artificial light sources, which are commonly used in operating theaters. Six dilutions of the fluorophores were imaged in phantom kits using the two camera systems. The limit of detection (LOD) and mean signal-to-background ratio (mSBR) were determined. The highest values of mSBR and a lower LOD were obtained in dark conditions for both systems. Under room lights, the capabilities decreased, but the mSBR remained greater than 3 (=clearly detectable signal). LOD and mSBR worsened under surgical lights for both camera systems, with a greater impact from halogen bulbs on VisionsenseTM VS3 Iridium and of the LED lights on IC-Flow due to a contribution of these lights in the near-infrared spectrum. When considering implementing FGS into the clinical routine, surgeons should cautiously evaluate the spectral contribution of the lights in the operating theater

Performance of two clinical fluorescence imaging systems with different targeted and non-targeted near-infrared fluorophores: a cadaveric explorative study

Near-infrared (NIR) fluorescence-guided surgery is increasingly utilized in humans and pets. As clinical imaging systems are optimized for Indocyanine green (ICG) detection, the usage of targeted dyes necessitates the validation of these systems for each dye. We investigated the impact of skin pigmentation and tissue overlay on the sensitivity of two NIR cameras (IC-FlowTM, VisionsenseTM VS3 Iridum) for the detection of non-targeted (ICG, IRDye800) and targeted (AngiostampTM, FAP-Cyan) NIR fluorophores in an ex vivo big animal model

Lymph node metastasis in feline cutaneous low-grade mast cell tumours

Objectives This retrospective study aimed to determine the incidence of nodal metastatic disease in cats affected by low-grade cutaneous mast cell tumours (MCTs) in our study population. Methods The clinical records of two centres were retrospectively searched for cats with cutaneous MCTs that had undergone lymphadenectomy of enlarged and non-enlarged lymph nodes. All primary tumours were histologically reviewed by two experienced pathologists and graded as high- or low-grade based on the grading system for feline cutaneous MCT. We graded the lymph nodes based on the grading scheme used for canine MCTs and considered HN2 and HN3 nodes to be metastatic. The number of patients with nodal metastasis was calculated. Results We identified 17 cats with cutaneous MCT resection and concurrent lymphadenectomy. All 21 MCTs were graded as low grade and 30 nodes were removed, with 12 being considered early or overtly metastatic (HN2 or HN3, respectively). Based on nodal status, 10/17 (59%) cats were affected by nodal metastasis in our population. Conclusions and relevance In contrast to previous reports, high percentage of cats with cutaneous MCTs in which lymphadenectomy was performed were presented with metastatic lymph nodes. The clinical relevance of this finding and a potential benefit of lymphadenectomy must be determined in future studies

Comparison of immediate and short‐term outcomes of cricoarytenoid and thyroarytenoid lateralization in dogs with idiopathic laryngeal paralysis

Objective: To compare the immediate and short-term outcomes of thyroarytenoid lateralization (TAL) and cricoarytenoid lateralization (CAL) for the treatment of canine laryngeal paralysis in dogs. Study design: A prospective, clinical trial. Animals: Fourteen client-owned dogs referred to our hospital because of bilateral laryngeal paralysis. Methods: Dogs with confirmed laryngeal paralysis were randomly assigned to the CAL or TAL group. Video images of the rima glottidis obtained preoperatively, immediately postoperatively (t0), and 15 days postoperatively (t1) were digitized. The rima glottidis area was measured using image-analysis software. An increase in the rima glottidis area was expressed as a percentage of the preoperative area. Results: The rima glottidis area increased by a mean of 152% at t0 and 127% at t1 for the TAL group and 205% at t0 and 199% at t1 for the CAL group compared with preoperative values. The increase in the rima glottidis area differed (P .05) in the CAL group but there was a large difference (P < .05) in the TAL group. Conclusion: Cricoarytenoid lateralization and TAL were both effective for surgical abduction of the arytenoid cartilage. Although a reduction (P < .05) in the rima glottidis area occurred in the TAL group at t1, we observed no associated clinical signs. Clinical significance: Cricoarytenoid lateralization and TAL result in good short-term outcomes in dogs with laryngeal paralysis

Sentinel Lymph Node Mapping and Biopsy in Cats with Solid Malignancies: An Explorative Study

There is increasing evidence on the utility of sentinel lymph node (SLN) biopsy (SLNB) for the staging of dogs with various malignancies; however, comparable information is missing in cats. This multi-institutional study aims at reporting the feasibility and detection rate of SLNB guided by lymphoscintigraphy and the blue dye or near-infrared fluorescent lymphography (NIRF-L) in cats with solid tumors. In total, 12 cats presented with 14 solid malignancies that underwent curative-intent surgical excision of the primary tumor and SLNB were retrospectively enrolled. The mapping technique used, location and number of SLN, correspondence with the regional lymph node (RLN), and histological status of the SLN were retrieved. The detection rate and complications of SLNB were also recorded. NIRF-L was performed in 64.3% of tumors and lymphoscintigraphy in 35.7%. The detection rate was 100% for both techniques. The SLN did not correspond (fully or partially) to the RLN in 71.4% of cases, with multiple SLN being excised in 9/14 tumors. No complications related to SLNB were recorded. At histopathology, metastases were identified in 41.7% of cats, all with mast cell tumors (MCT). SLNB guided by NIRF-L or lymphoscintigraphy is feasible and safe in cats with solid tumors and should be suggested for correct tumor staging in cats, especially with MCT

Surgical Margins in Canine Cutaneous Soft-Tissue Sarcomas: A Dichotomous Classification System Does Not Accurately Predict the Risk of Local Recurrence

Adjuvant treatments are recommended in dogs with incompletely excised cutaneous soft-tissue sarcoma (STS) to reduce the risk of local recurrence (LR), although guidelines are lacking on how to manage clean but close margins (CbCM). This retrospective study investigates the impact of CbCM on LR of canine STS. Ninety-eight surgically excised canine STS at first presentation were included. Tissue samples were routinely trimmed and analyzed. Cumulative incidence of LR was estimated for each category of margins (tumor-free, infiltrated, CbCM), and included CbCM in the tumor-free and infiltrated category, respectively. The prognostic impact on LR was then adjusted for relevant prognostic factors. Cumulative incidence of LR at three years differed significantly between the three categories (p = 0.016), and was estimated to be 42% with infiltrated margins, 23% with CbCM, 7% with tumor-free margins. Both when CbCM were grouped with infiltrated margins (p = 0.033; HR = 5.05), and when CbCM were grouped with tumor-free margins (p = 0.011; HR = 3.13), a significant difference between groups was found. STS excised with infiltrated margins had the greatest risk of LR. The rate of LR with CbCm was greater than recurrence rate of tumor-free margins. The category CbCM may be considered as a separate prognostic category

Salivary miR-21 is a potential biomarker for canine mast cell tumors

MicroRNAs (miRNAs) are a class of noncoding RNA molecules playing a crucial role in tumor modulation targeting mRNA. This study aimed to validate the diagnostic potential of a panel of 3 miRNAs previously identified in canine mast cell tumors (MCTs), miR-21, miR-379, and miR-885, as markers of lymph node involvement in terms of histological absence (nonmetastatic: HN0; premetastatic: HN1) and presence (early-metastatic: HN2; overt-metastatic: HN3) of metastasis, in the saliva of mast cell tumor (MCT)-affected dogs by quantitative polymerase chain reaction (PCR). Forty-seven saliva samples were analyzed: 36 from MCT-affected dogs (12 subcutaneous [3 HN0-1 and 9 HN2-3] and 24 cutaneous [9 HN0-1 and 15 HN2-3—MCT]) and 11 from healthy dogs. MCT-group effects were investigated using analysis of variance (ANOVA). The origin of the tumor affected the expression of salivary miR-21 ( P = .011) with an increase in cases with subcutaneous MCTs compared with the healthy group ( P = .0005) and those with cutaneous MCTs ( P = .004). Salivary miR-21 was higher in the HN2-3 class compared with the healthy group ( P = .004). Salivary miR-885 was not affected by the presence of MCT, while miR-379 was not detected in saliva. The diagnostic potential of salivary miR-21 in discriminating MCT-affected dogs from the healthy group (AUC = 0.8917), cutaneous from subcutaneous (AUC = 0.8111), and subcutaneous HN0-1 (AUC = 0.7250) and HN2-3 (AUC = 0.9750) classes from healthy samples was demonstrated by receiver operating characteristic curve analysis. Overall, salivary miR-21 was identified as a promising tool, representing a novel approach to detecting MCT-associated epigenetic alterations in a minimally invasive manner

Evaluation of Surgical Aid of Methylene Blue in Addition to Intraoperative Gamma Probe for Sentinel Lymph Node Extirpation in 116 Canine Mast Cell Tumors (2017–2022)

Methylene Blue (MB) is combined with radiopharmaceutical for intraoperative sentinel lymph node (SLN) mapping, but its role during SLN extirpation has not been investigated yet in veterinary medicine. The aim of this study was to assess whether MB increased surgical detection of SLN beyond the use of intraoperative gamma-probe (IGP) alone in clinically node-negative dogs with mast cell tumors (MCTs) following the detection of sentinel lymphocentrums (SLCs) via preoperative planar lymphoscintigraphy. Dogs enrolled underwent MCT excision and SLC exploration guided by both MB and IGP. Data recorded for each SLN were staining (blue/non-blue), radioactivity (hot/non-hot), and histopathological status (HN0-1 vs. HN2-3). A total of 103 dogs bearing 80 cutaneous, 35 subcutaneous, and 1 mucocutaneous MCTs were included; 140 SLCs were explored, for a total of 196 SLNs removed. Associating MB with IGP raised the SLNs detection rate from 90% to 95%. A total of 44% of SLNs were metastatic: 86% were blue/hot, 7% were only blue, 5% were only hot, and 2% were non-blue/non-hot. All HN3 SLNs were hot. Combining MB with IGP can increase the rate of SLN detection in dogs with MCTs; nonetheless, all lymph nodes identified during dissection should be removed, as they might be unstained but metastatic

Preliminary assessment of Mesenchymal To Epithelial Transition in canine perivascular wall tumors (PWTs): E-cadherin, β-catenin and cytokeratins immunohistochemical expression

Epithelial to mesenchymal transition (EMT) has a major role in tumor progression and metastasis of carcinomas in humans and dogs. Recent findings suggest that the reverse process, mesenchymal to epithelial transition (MET), occurs in sarcomas and has been associated with decreased cell proliferation, invasion, and migration leading to a better prognosis.1 Mesenchymal cells undergoing MET acquire an epithelial-like phenotype by gaining expression of typical epithelial markers (cytokeratins, β-catenin, and E-cadherin). Studies regarding MET in canine sarcomas are scarce2 and the correlation between EMT or MET and prognosis has not been investigated fully. Canine perivascular wall tumors (PWTs) display a general more favourable behaviour compared to other soft tissue sarcomas.3 Our hypothesis is that in PWTs the development of MET phenotype may be one of the factors involved in their distinctive behaviour. Thus, the aim of this work was to explore the occurrence of MET by assessment of specific marker expression by immunohistochemistry (IHC) in canine PWTs. A series of 36 canine PWTs were routinely processed and stained with anti-pan-cytokeratin (AE1/AE3), -β-catenin, and -E-cadherin. IHC results and histologic grades were recorded for all tumors. Cases resulted grade 1 (23/38), grade 2 (12/38) and grade 3 (3/38). All cases were pan-cytokeratins negative. Nuclear and cytoplasmic expression of E-cadherin (38/38) and β-catenin (31/36) were observed. E-cadherin is involved in cell-to-cell adhesion and normally absent in normal vascular mural cells.4,5 E-cadherin and β-catenin expression may either reflect MET transition in PWTS or be indicative of a dysregulation of their corresponding pathways. [1] Yang et al. Mesenchymal to epithelial transition in sarcomas, European Journal of Cancer, 50(3):593-601, 2014. [2] Armando et al. Mesenchymal to epithelial transition driven by canine distemper virus infection of canine histiocytic sarcoma cells contributes to a reduced cell motility in vitro, Journal of Cellular and Molecular Medicine, 24(16):9332-9348, 2020. [3] Avallone et al. The controversial histologic classification of canine subcutaneous whorling tumours: The path to perivascular wall tumours, Veterinary Comparative Oncology, 18(1):3-8, 2020. [4] George et al. Cadherin:catenin complex: a novel regulator of vascular smooth muscle cell behaviour, Atherosclerosis, 188(1): 1–11, 2006. [5] Frismantiene et al. Cadherins in vascular smooth muscle cell (patho)biology: Quid nos scimus? Cellular signalling, 45: 23–42, 2018