Quentin Cabon

Evaluation of intraoperative fluorescence imaging–guided surgery in cancer-bearing dogs: a prospective proof-of-concept phase II study in 9 cases

The objective was to prospectively evaluate the application of intraoperative fluorescence imaging (IOFI) in the surgical excision of malignant masses in dogs, using a novel lipid nanoparticle contrast agent. Dogs presenting with spontaneous soft-tissue sarcoma or subcutaneous tumors were prospectively enrolled. Clinical staging and whole-body computed tomography (CT) were performed. All the dogs received an intravenous injection of dye-loaded lipid nanoparticles, LipImage 815. Wide or radical resection was realized after CT examination. Real-time IOFI was performed before skin incision and after tumor excision. In cases of radical resection, the lymph nodes (LNs) were imaged. The margin/healthy tissues fluorescence ratio or LN/healthy tissues fluorescence ratio was measured and compared with the histologic margins or LN status. Nine dogs were included. Limb amputation was performed in 3 dogs, and wide resection in 6. No adverse effect was noted. Fluorescence was observed in all 9 of the tumors. The margins were clean in 5 of 6 dogs after wide surgical resection, and the margin/healthy tissues fluorescence ratio was close to 1.0 in all these dogs. Infiltrated margins were observed in 1 case, with a margin/healthy tissues fluorescence ratio of 3.2. Metastasis was confirmed in 2 of 3 LNs, associated with LN/healthy tissues fluorescence ratios of 2.1 and 4.2, whereas nonmetastatic LN was associated with a ratio of 1.0. LipImage 815 used as a contrast agent during IOFI seemed to allow for good discrimination between tumoral and healthy tissues. Future studies are scheduled to evaluate the sensitivity and specificity of IOFI using LipImage 815 as a tracer.

Phase-0/phase-I study of dye-loaded lipid nanoparticles for near-infrared fluorescence imaging in healthy dogs.

Near-infrared (NIR) fluorescence imaging using FDA-approved indocyanine green (ICG) has been the subject of numerous studies during the past few years. It could constitute a potentially exciting new paradigm shift in veterinary oncology, especially to develop in vivo fluorescence imaging diagnostics and surgery guidance methods. The objective of this study was to evaluate the pharmacologic and toxicological characteristics in healthy beagle dogs of LipImage™ 815, a formulation made of NIR-dye-loaded lipid nanoparticles. The initial dosage for the evaluation of biodistribution was extrapolated from data in mice and then adapted to define the more adapted dose (MAD) according to the fluorescence results obtained in 5 dogs using a Fluobeam® 800 imaging device (phase 0 study). A single dose acute toxicity study was then performed (3 dogs, phase I study). Before the systemic administration of LipImage™ 815, the dogs presented a very mild residual fluorescence, particularly in the liver and kidneys. After injection, the plasma fluorescence continuously decreased, and the signal was relatively homogeneously distributed throughout the different organs, though more pronounced in the liver and to a lesser extent in the steroid-rich organs (adrenal, ovaries), intestines, lymph nodes and kidneys. A MAD of 2.0μg/kg was found. No evidence of acute or delayed general, hepatic, renal or hematologic toxicity was observed at 1-fold, 5-fold or 10-fold MAD. The results of this phase-0/phase-I study showed that an optimal dosage of LipImage™ 815 of 2.0μg/kg allowed the achievement of a fluorescence signal suitable for surgery guidance application without any acute side effects.

Placement of subcutaneous ureteral bypasses without fluoroscopic guidance in cats with ureteral obstruction: 19 cases (2014–2016)

Objectives The purpose of this study was to describe the perioperative and postoperative complications as well as short-term and long-term outcomes in cats with ureteral obstructions treated by placement of a subcutaneous ureteral bypass (SUB) device without imaging control. The second objective of this study was to compare cats treated by SUB device with cats treated by traditional surgical intervention. Methods Data were obtained retrospectively from the medical records (2014–2016) of cats that underwent SUB placement (SUB cats) and cats that underwent traditional ureteral surgery (C cats). Results Nineteen SUB devices were placed without fluoroscopic, radiographic or ultrasonographic guidance in 13 cats. Fifteen traditional interventions (ureterotomy and neoureterocystostomy) were performed in 11 cats. Successful placement of the SUB device was achieved in all cats with only one major intraoperative complication (kinking of the kidney catheter) and one minor intraoperative complication (misplacement of the kidney catheter). Eleven SUB cats recovered from the surgical procedure; two SUB cats and three C cats died during the anaesthesia recovery period. Postoperative SUB complications included anaemia (n = 2), urinary tract infection (UTI) (n = 4), non-infectious cystitis (n = 5) and SUB device obstruction (n = 1). Postoperative traditional surgery complications included anaemia (n = 7), UTIs (n = 6), non-infectious cystitis (n = 1), re-obstruction (n = 4) and ureteral stricture (n = 1). Median postoperative duration of hospitalisation (3 days) was significantly shorter for SUB cats than for C cats (P = 0.013). Ten SUB cats (76.9%) and four C cats (40%) were still alive at a median follow-up of 225 days and 260 days, respectively. Owners were completely (90%) or mostly (10%) satisfied with the SUB device placement. Conclusions and relevance SUB device placement appears to be an effective and safe option for treating ureteral obstruction in cats, and this study has shown that fluoroscopic guidance is not essential in all cases.

Evaluation of a new method to determine the tibial tuberosity advancement distance required to reduce the patellar tendon-tibial plateau angle to 90° with the modified Maquet technique in dogs

OBJECTIVE To assess use of a new radiographic method to determine the distance by which the tibial tuberosity should be advanced to reduce the patellar tendon-tibial plateau angle (PTA) to 90° by means of the modified Maquet technique (MMT) in dogs. SAMPLE 24 pelvic limbs from 12 adult medium-sized to large-breed canine cadavers. PROCEDURES Radiographs of stifle joints at 135° extension in true lateral position were used to determine tibial tuberosity advancement distances for use in the MMT. A method was devised to incorporate the planned osteotomy axis; distal patellar translations of 0, 3, 5, or 10 mm; and advancement cage implant application level along the osteotomy site in advancement planning measurements. Concordance correlation coefficients (CCCs) were calculated to compare these adjusted advancement measurements with true advancement measurements obtained for the same joints in another study after treatment by MMT. Intraobserver, interobserver, and total agreement for selected measurements were determined by assessment of CCCs for results obtained by 3 blinded observers. RESULTS Agreement between true advancement measurements and measurements obtained with osteotomy axis and cage position method calculations that incorporated a 5-mm distal patellar translation distance was excellent (CCC, 0.96). Intraobserver and interobserver agreements for the planning measurements evaluated were good to excellent (CCC, 0.83 to 0.96). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the osteotomy axis and cage position method incorporating a 5-mm distal patellar translation distance has the potential to improve success rates for achieving a PTA of 90° in medium-sized to large-breed dogs undergoing MMT for treatment of cranial cruciate ligament rupture. Further research is warranted.

Surgical treatment of a bilateral patellar fracture in a young adult dog

A 15-month-old female Belgian Malinois presented with an inability to ambulate on its pelvic limbs after running away. Orthopaedic examination revealed painful stifles, crepitus and a bilateral lack of patellar continuity. Radiographs confirmed bilateral patellar fractures showing a similar fracture pattern on both sides, with three parts divided in the shape of a ‘Y’. Surgical treatment consisted of fracture stabilisation using pins and wires protected by a tibio-patellar prosthesis and type Ia external fixator. Bone healing occurred and a satisfactory level of function was observed at long-term follow-up. This report describes the original presentation of bilateral patellar fractures in a dog. The bilateral presentation and similar fracture pattern on both sides potentially support the notion that failure of the patellar secondary ossification centres to unite caused fragility of both patellae.