The relevance of regional lymph node (LN) assessment to quantify the metastatic spread of cancer is well recognized in veterinary oncology. Evaluation of LNs is critical for tumour staging. However, sampling the correct LN may not be possible without sentinel lymph node (SLN) mapping. Methods for diagnostic imaging and intraoperative detection of SLNs are well established in human medicine, in particular, the combination of lymphoscintigraphy and intraoperative application of blue dyes. Nevertheless, alternative imaging techniques are available and have gained increasing interest. Successful implementation of these techniques in dogs have been reported in both clinical and experimental studies. This review aims to provide an overview of SLN mapping techniques in human and veterinary medicine.

ObjectiveTo compare the accuracy of pedicle screw insertion (PSI) into canine lumbosacral vertebrae with custom‐made three‐dimensionally (3D)‐printed drill guides or freehand insertion.Study designEx vivo study.Sample populationNineteen canine lumbosacral specimens.MethodsDrill guides for PSI were designed on the basis of safe screw insertion trajectories by using preoperative computed tomography (CT) and produced by 3D printing of templates. Right and left sides of the specimens were randomly allocated to two groups; 4‐mm pedicle screws were inserted in L5‐L6 and L7‐S1 spinal segments either freehand (control group) or with custom‐made drill guides (guide group). Sixty‐six screws were inserted with each method. Insertion angles (α, β), bone stock, and vertebral canal breach were assessed according to postoperative CT. χ2 Tests were used to compare vertebral canal breach between groups and vertebrae.ResultsBreaches in the vertebral canal were less common (P < .001) when screws were placed with a guide in the guide group (9/66, 14%) than without a guide (30/66, 45%). The rate of vertebral canal breach differed at L5 (P = .021) but not at L6 (P = .05), L7 (P = .075) or S1 (P = .658). The angle of insertion (α) did not differ between specimens with and without breaches (guide, P = .068; control, P = .394).ConclusionThe use of a customized 3D‐printed guide generally improved the accuracy of PSI in canine lumbosacral vertebrae, although statistical significance was reached only at L5.Clinical significanceThe use of customized drill guides may be considered as an alternative to freehand PSI in the lumbosacral area, especially for L5‐L6 vertebrae.

Objectives Near‐infrared fluorescent imaging has been described for intraoperative mapping of the draining lymph nodes in human cancer and canine oral tumours. The aim of this study was to retrospectively describe the results of lymphadenectomies in dogs with mast cell tumours treated either by standard unguided locoregional lymph node dissection or near‐infrared fluorescent image‐guided lymph node dissection. Methods Medical records between 2012 and 2020 were reviewed for dogs that were presented for surgical resection of mast cell tumours with concurrent lymphadenectomy either with (near‐infrared fluorescent image‐guided lymph node dissection) or without near‐infrared fluorescence image guidance (lymph node dissection). The number and location of lymph nodes planned for surgical dissection and actually dissected nodes, presence of metastases and perioperative complications were recorded. Results Thirty‐five patients underwent near‐infrared fluorescent image‐guided lymph node dissection, and 43 lymph node dissections. The number of nodes preoperatively planned for resection were 70 and 68, respectively. Fifty‐eight of those (83%) were identified during near‐infrared fluorescent image‐guided lymph node dissection procedures, compared with 50 (74%) during lymph node dissection. near‐infrared fluorescent image‐guided lymph node dissection resulted in resection of additional fluorescent nodes not corresponding to locoregional nodes in 15 of 35 dogs. Using near‐infrared fluorescent image‐guided lymph node dissection, we identified at least one metastatic node in 68% of dogs (24 of 35) compared with 33% (14 of 43) when lymph node dissection was used without imaging. No complications related to near‐infrared fluorescent imaging were reported. Clinical Significance The present study suggests that near‐infrared imaging is a promising technique for intraoperative detection of the draining lymph nodes in dogs with mast cell tumours. Further validation of the technique is required to assess if near‐infrared fluorescent imaging can detect the true sentinel lymph node.

Summary Objective: The optimal surgical technique for treatment of cranial cruciate ligament rupture in canine has been scientifically discussed for decades. Despite the continuous debate, proximal tibial osteotomies such as tibial plateau leveling osteotomy (TPLO) and tibial tuberosity advancement (TTA) are increasingly common. The objective of this review was to systematically evaluate the literature reporting outcome and complications associated with TPLO and TTA. Materials and methods: A systematic search of literature databases identified articles published from August 2004 to February 2016 describing evaluations of short- or longterm outcomes as well as complications following TPLO or TTA. Results: Ninety-one studies were included in this review and assigned to one out of four evidence levels. Of those, 89 studies provided the lowest evidence level and only two were assigned to the third-best evidence level. A comparison of subjective gait analyses could not detect differences in the decrease of lameness between TPLO and TTA, while objective gait analysis supports the superiority of TPLO. Fewer patients treated with TPLO were diagnosed with postoperative joint instability and TPLO had a lower percent increase of osteoarthritis (OA) after surgery. Owner satisfaction was high for both techniques. For TPLO and TTA the average total, minor, major and catastrophic complication rates were 15.9 % and 20.8 %, 7.9 % and 11.6 %, 5.2 % and 13.2 % as well as 0.8 % and 5.6 %, respectively. Conclusion and clinical significance: The assessed literature supports the hypothesis that TPLO is associated with lower complication rates, an improved clinical-functional outcome and less increase of OA compared to TTA. The results are indicative for a long-term restoration of normal limb function after TPLO. However, the strength of available evidence and the comparability of each study’s results were poor and more comparative studies are needed to draw strong conclusions towards the superiority of the TPLO over the TTA.

Lymph node status is an important prognostic factor in multiple oncologic conditions in humans and companion animals. In addition, the resection of the affected nodes can have a substantial therapeutic effect on various cancer subtypes in both species. Given the impact on prognosis and management, it is paramount to identify and remove affected nodes. While this can be achieved by removing predefined patterns of nodes (regional lymphadenectomy/resection of defined lymphatic stations), modern approaches increasingly utilize sentinel node mapping to identify the draining nodes to decrease the mortality of lymphadenectomies. Recent studies have shown that dogs have more comparable anatomy of the lymphatic system to humans than other animal models such as rodents or pigs. Given the fact that dogs develop spontaneous cancer types that share several similarities to their human counterparts, they represent a valuable translational model. The management of the lymphatic basin and sentinel node mapping have gained increased attention in veterinary surgical oncology in recent years. The present review aims at summarizing the resulting findings and their impact on patient management.

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IntroductionNear-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.MethodsWe quantitatively measured the limit of detection (LOD) and signal-to-background ratio (SBR) and implemented a semi-quantitative visual score to account for subjective interpretation of images by the surgeon.ResultsVisionsenseTM VS3 Iridum outperformed IC-FlowTM in terms of LOD and SBR for the detection of all dyes except FAP-Cyan. Median SBR was negatively affected by skin pigmentation and tissue overlay with both camera systems. Level of agreement between quantitative and semi-quantitative visual score and interobserver agreement were better with VisionsenseTM VS3 Iridum.ConclusionThe overlay of different tissue types and skin pigmentation may negatively affect the ability of the two tested camera systems to identify nanomolar concentrations of targeted-fluorescent dyes and should be considered when planning surgical applications.