Michelle L Oblak

University of Guelph | UOGuelph · Department of Clinical Studies

In the field of veterinary oncology, lymphadenectomy can play an important role in our veterinary patients with regard to clinical staging, determining prognosis, developing treatment plans, and decreasing tumor burden. For a given oncologic disease, peripheral regional lymph nodes should be carefully palpated for enlargement, asymmetry, and degre...

Objective To compare ventral cervical and bilateral lateral incisions for extirpation of mandibular and medial retropharyngeal lymph nodes in dogs. Study design Prospective randomized, crossover controlled cadaver trial. Sample population Eight veterinarians with advanced surgical training. Methods Study participants were randomized to perform b...

Certain 3D printed metals and surface finishes may be better suited for canine patient specific orthopedic implants on the basis of minimizing potential bacterial biofilm growth. Thirty disks each of titanium alloy, stainless steel, and cobalt chromium alloy were 3D printed via laser powder bed fusion. Fifteen disks of each metal were subsequently...

This study's objective was to determine the accuracy of using current computed tomography (CT) scan and software techniques for rapid prototyping by quantifying the margin of error between CT models and laser scans of canine skull specimens. Twenty canine skulls of varying morphology were selected from an anatomy collection at a veterinary school....

OBJECTIVE To conduct a retrospective multi-institutional study reporting short- and long-term outcomes of adrenalectomy in patients presenting with acute hemorrhage secondary to spontaneous adrenal rupture. ANIMALS 59 dogs and 3 cats. METHODS Medical records of dogs and cats undergoing adrenalectomy between 2000 and 2021 for ruptured adrenal mass...

Objective: To compare the effect of volume and solution on transit time and fluorescence intensity (FI) using near-infrared fluorescence imaging (NIRF) in a simulated tumor model in cats. Secondarily, to describe SLN mapping with indocyanine green (ICG) NIRF and report any adverse effects of intradermally injected ICG in cats. Animals: 7 healthy...

Enumeration of circulating tumour cells (CTC) has shown promise for prognostication and guidance of therapeutic decisions in human cancers. The objective of this study was to enumerate CTC over time in dogs with naturally occurring osteosarcoma (OSA), and to determine correlation with patient outcome. Twenty-six dogs with OSA and no evidence of met...

OBJECTIVE To evaluate short- and long-term outcomes for dogs undergoing anal sacculectomy for massive (> 5 cm) apocrine gland anal sac adenocarcinoma (AGASACA). ANIMALS 28 client-owned dogs with massive AGASACA. PROCEDURES A retrospective multi-institutional study was performed. Pre-, intra-, and post-operative data was collected, and variables w...

Objective: To investigate the perioperative complications and outcomes of rabbits undergoing partial ear canal ablation and lateral bulla osteotomy for treatment of chronic otitis. Materials and methods: Surgical logbooks were searched to identify rabbits that underwent partial ear canal ablation and lateral bulla osteotomy between December 2009...

Nasal planum tumors are rare in cats, with squamous cell carcinoma over-represented. Other skin tumors have been reported in this location and though hemangiosarcoma frequently occurs on the skin of the head, these tumors localized to the nasal planum have not been specifically reported. The objectives of this study were to report the clinical find...

Background In humans, kidney injury molecule-1 (KIM-1) is a biomarker of acute kidney injury that can be quantified in urine. Preliminary investigation in cats with experimentally induced acute kidney injury showed that KIM-1 urine concentration correlated with kidney injury histopathology scores. A lateral flow assay (LFA) has recently become avai...

Despite the important role of preclinical experiments to characterize tumor biology and molecular pathways, there are ongoing challenges to model the tumor microenvironment, specifically the dynamic interactions between tumor cells and immune infiltrates. Comprehensive models of host-tumor immune interactions will enhance the development of emergin...

Background A variety of urolith types have been reported in macropods, but reports of successful treatment are scarce. Case Description A 10-month-old, intact male, privately-owned red kangaroo (Osphranter rufus) joey was presented for hemorrhage and self-inflicted trauma to the penis. Physical examination findings included a large, firm, non-expr...

Surgical removal is the treatment of choice for subcutaneous (SC), intermuscular (InterM), and intramuscular (IntraM) mast cell tumors (MCTs). Advanced imaging (CT or MRI) is frequently used for presurgical planning, but InterM and IntraM MCTs can be difficult to identify and delineate on CT. Aims of the current retrospective, diagnostic accuracy,...

Objective: To report the outcomes of dogs that underwent primary repair of gastroduodenal perforations associated with the administration of nonsteroidal anti-inflammatory drugs (NSAID). A secondary objective was to identify clinicopathological findings that predisposed dogs to postoperative death. Study design: Retrospective study. Animals: E...

OBJECTIVE To report the perioperative characteristics and outcomes of dogs undergoing laparoscopic-assisted splenectomy (LAS). ANIMALS 136 client-owned dogs. PROCEDURES Multicentric retrospective study. Medical records of dogs undergoing LAS for treatment of naturally occurring splenic disease from January 1, 2014, to July 31, 2020, were reviewed...

OBJECTIVE To describe veterinary house officers’ perceptions of dimensions of well-being during postgraduate training and to identify potential areas for targeted intervention. SAMPLE 303 house officers. PROCEDURES A 62-item questionnaire was generated by use of an online platform and sent to house officers at participating institutions in Octobe...

Objective: To determine the outcome of dogs with soft tissue sarcoma (STS) within the region of the ischiatic tuberosity (ITSTS) treated surgically. Study design: Multi-institutional retrospective study ANIMALS: Fifty-two client-owned dogs with histologically confirmed STS in the region of the IT treated with surgical resection between March 1st...

Osteosarcoma (OS) is a highly malignant bone tumour that has seen little improvement in treatment modalities in the past 30 years. Understanding what molecules contribute to OS biology could aid in the discovery of novel therapies. Extracellular vesicles (EVs) serve as a mode of cell-to-cell communication and have the potential to uncover novel pro...

Thoracoscopic access can be associated with major morbidity as many vital structures reside close to commonly used port positions. Maintenance of good technique during access is imperative to avoid complications. Thoracoscopic procedures performed in dorsal recumbency usually involve placement of a subxiphoid telescope portal that is used to visual...

Objective: To describe the clinical characteristics, perioperative protocols, and outcomes in dogs diagnosed with ventricular fibrillation (VF) while undergoing pericardiectomy. Study design: Retrospective, multi-institutional study. Animals: Sixteen client-owned dogs. Methods: Cases were accrued through a listserve request posted to 3 subsp...

OBJECTIVE To compare the long-term outcomes of a ventral versus lateral surgical approach for mandibular and sublingual sialoadenectomy in dogs with a unilateral sialocele. ANIMALS 46 client-owned dogs. PROCEDURES Medical records of dogs that underwent unilateral sialoadenectomy between 1999 and 2019 were retrospectively reviewed, and information...

Objective: To provide updated information on the distribution of histopathologic types of primary pulmonary neoplasia in dogs and evaluate the effect of postoperative adjuvant chemotherapy in dogs with pulmonary carcinoma. Animals: 340 dogs. Procedures: Medical records of dogs that underwent lung lobectomy for removal of a primary pulmonary ma...

Sertoli cell tumours are one of the most common canine testicular neoplasia. These tumours are significantly more likely to arise in cryptorchid dogs and are often functional, oestrogen-secreting tumours which can lead to fatal myelotoxicity. The goal of this study was to describe the outcome of dogs with oestrogen-induced bone marrow suppression s...

Background: To develop a digital algorithm for quantitative assessment of surface methylene blue staining in whole lymph nodes and validate a semi-quantitative visual scoring method for patient-side use. Methods: Lymph nodes from canine patients with spontaneous tumors undergoing sentinel lymph node mapping were prospectively assessed ex vivo and p...

A combination of pre and intraoperative sentinel lymph node (SLN) mapping techniques have been suggested to optimize SLN detection. A novel liposomal nanoparticle, Nanotrast-CF800 (CF800), utilizes computed tomography lymphography (CTL) and near infrared fluorescence imaging (NIRF) for image-guided surgery and SLN mapping. This novel tracer agent h...

Objective: To provide information about complication rates and the risk factors for complications with mandibulectomy and maxillectomy procedures in dogs. Animals: 459 client-owned dogs that underwent a mandibulectomy or maxillectomy between January 1, 2007, and January 1, 2018. Procedures: Inclusion criteria included a complete medical record...

A combination of pre- and intraoperative sentinel lymph node (SLN) mapping techniques have been suggested to optimize SLN detection. A novel liposomal nanoparticle, Nanotrast-CF800 (CF800), utilizes computed tomography lymphography (CTL) and near infrared fluorescence imaging (NIRF) for image-guided surgery and SLN mapping. This novel tracer agent...

Standardization of tumor assessment lays the foundation for validation of grading systems, permits reproducibility of oncologic studies among investigators, and increases confidence in the significance of study results. Currently, there is minimal meth-odological standardization for assessing tumors in veterinary medicine, with few attempts to vali...

Objective: To evaluate outcomes associated with the use of an angularis oris axial pattern flap (AOAPF) for rostral facial reconstruction in cats. Animals: Nine adult client-owned cats. Study design: Short case series. Methods: Ten AOAPF were performed in nine cats after resection of a tumor. Wounds were located at the nose, infraorbital, su...

Objective: To describe surgical management and associated outcomes for dogs with primary spontaneous pneumothorax. Animals: 110 client-owned dogs with primary spontaneous pneumothorax that underwent surgical management. Procedures: Medical records at 7 veterinary teaching hospitals were reviewed. Data collected included signalment, history, cl...

While the majority of canine osteosarcomas (OSA) arise from the medullary cavity, a subset arises from the surface of bone. In humans, surface OSA often has a more indolent disease course with better outcomes than medullary OSA. The aim of this retrospective case series was to evaluate the clinical outcome and potential prognostic factors of dogs w...

Capacity for Care (C4C) is a shelter management strategy which utilizes managed intake to optimize in-shelter populations based on housing capacity and available resources. The purpose of this study was to 1) understand staff experiences using managed intake, 2) explore staff perceptions of how the C4C model has been regarded by other staff at thei...

Capacity for Care (C4C) is a shelter management strategy that is capable of improving the welfare of cats in a shelter’s care. Managing shelter intake using intake waitlists and scheduled intake appointments is a key feature of C4C. The purpose of this study was to describe the population of owned cats whose owners contacted the Guelph Humane Socie...

Objectives To describe the use of near infrared fluorescence (NIRF) imaging with indocyanine green (ICG) for vascular visualization in two caudal auricular axial pattern flaps (APF). Animals Two client‐owned cats with upper eyelid masses. Study design Clinical case report. Methods Wide surgical excision with enucleation was performed by using a...

The updated VCOG‐CTCAE v2 guidelines contain several important updates and additions since the last update (v1.1) was released in 2011 and published within Veterinary and Comparative Oncology in 2016. As the Veterinary Cooperative Oncology Group (VCOG) is no longer an active entity, the original authors and contributors to the VCOG‐CTCAE v1.0 and v...

Lymphatic drainage from the head and neck is variable with significant crossover, therefore sentinel lymph node (SLN) mapping can help ensure the appropriate lymph nodes are sampled. To improve sensitivity, SLN mapping utilizing multiple modalities and a combination of preoperative computed tomography lymphography (CTL) and intraoperative near infr...

Objective To describe the clinical features and outcome of functional thyroid tumours in dogs. Materials and Methods Retrospective multi‐institutional study of 70 dogs diagnosed with thyroid mass and concurrent hyperthyroidism. Clinical data regarding presentation, treatment, outcome and functional thyroid status were retrieved. Results Overall m...

The effects of radiation therapy may be potentiated by combining radiation therapy with secondary therapies. Clinically, radiation therapy has been combined with bisphosphonates for treatment of canine appendicular osteosarcoma for years. The objective of this study was to determine if the timing of administration of bisphosphonates in relation to...

Background: Additive manufacturing has allowed for the creation of a patient-specific custom solution that can resolve many of the limitations previously reported for canine cranioplasty. The purpose of this pilot study was to determine the schedule feasibility and workflow in manufacturing patient-specific titanium implants for canines undergoing...

Objective To report the outcomes of dogs with lesions of the genitourinary tract treated by vaginectomy or vulvovaginectomy. Study design Multi‐institutional retrospective study. Animals Female dogs that underwent vulvovaginectomy, complete vaginectomy, or subtotal vaginectomy from 2003 to 2018 with complete medical records and a minimum of 60 da...

The purpose of this study was to evaluate post-operative outcome in dogs and cats undergoing perineal herniorrhaphy using porcine small intestinal submucosa (PSIS) alone and with internal obturator muscle transposition augmented with PSIS (IOMT + PSIS). Medical records were retrospectively reviewed and information collected on signalment, pre-opera...

Purpose To develop a digital algorithm and validate a semi-quantitative scoring method for surface methylene blue (MB) staining in whole lymph nodes (LN). Methods Lymph nodes from canine models undergoing sentinel lymph node (SLN) mapping were prospectively assessed ex vivo and photographed. Two blinded observers evaluated all images and assigned...

Objective: To determine whether conservative lateral surgical margins (equal to tumor diameter for tumors < 2 cm in diameter or 2 cm for larger tumors) were noninferior to wide (3-cm) lateral surgical margins for achieving tumor-free histologic margins following excision of grade I and II cutaneous mast cell tumors (MCTs) in dogs. Animals: 83 gr...

Objective: To compare long-term clinical outcomes of dogs with single congenital extrahepatic portosystemic shunts (CEHPSS) treated with thin film banding (TFB) consisting of polyolefin fiber or ameroid ring constrictor (ARC) placement in dogs. Design: Retrospective, two-center clinical study. Animals: Client-owned dogs (n = 123) with single C...

Ovarian remnant syndrome (ORS) is a condition resulting from incomplete removal of ovarian tissue during ovariectomy and/or ovariohysterectomy. Single-port laparoscopy (SPL) is an alternative to ventral midline laparotomy for treatment of ORS. Medical records of 13 client-owned female dogs who underwent SPL for the treatment of ORS were retrospecti...

A 3-year-old, male neutered domestic shorthair cat, presented for acute onset tail paresis. He was diagnosed with a spindle cell tumour at the level of L7-CD1 and treated with course fractionation radiation therapy. Three years following radiation therapy, the cat developed chondroblastic osteosarcoma of the pelvis, suspected to be secondary to rad...

A 9-year-old spayed female dachshund presented with a large multilobular osteochondrosarcoma of the crania, with obliteration of approximately 70% of the surface area of the dorsal calvaria and intracranial extension. The mass was excised with histologically clean lateral bone margins (2–4 mm) and invasion at the deep margin. The resulting defect w...

OBJECTIVE To compare complications and outcome following unilateral, staged bilateral, and single-stage bilateral ventral bulla osteotomy (VBO) in cats. ANIMALS 282 client-owned cats treated by VBO at 25 veterinary referral and academic hospitals from 2005 through 2016. PROCEDURES Medical records of cats were reviewed to collect information on sign...

Objective: To evaluate reporting of surgical complications and other adverse events in clinical research articles describing soft tissue and oncologic surgery in dogs and cats. Study design: Systematic literature review. Sample: English-language articles describing soft tissue and oncologic surgeries in client-owned dogs and cats published in...

Osteosarcoma (OSA) is a malignant tumor of middle‐aged dogs and adolescent humans. The clinical outcome of OSA has not improved over more than three decades, and dogs typically succumb to metastatic disease within 6 months despite tumor resection through limb amputation and adjuvant chemotherapy. Therefore, undetectable tumor cells with potential t...

The purpose of this retrospective cross-sectional study was to assess the diagnostic yield of ultrasound-guided aspiration of the medial retropharyngeal lymph node (MRPLN) and to report factors on computed tomography (CT) evaluation that are predictive of obtaining a diagnostic sample. A secondary objective was to report CT size reference ranges fo...

Objective To describe the clinical characteristics, perioperative complications, and outcomes in dogs surgically treated for gastric carcinoma. Study design Multi‐institutional retrospective case series. Animals Forty client‐owned dogs with histologically confirmed gastric carcinoma. Methods Medical records were reviewed for preoperative diagnos...

Additive manufacturing has allowed for the creation of a patient-specific custom solution that can resolve many of the limitations previously reported for canine cranioplasty. The purpose of this pilot study was to determine the schedule feasibility and workflow in manufacturing patient-specific titanium implants for canines undergoing cranioplasty...

A 9-year-old spayed female Labrador retriever dog was diagnosed with a grade 1 chondrosarcoma associated with the right iliopsoas muscle. A computed tomography scan of the patient revealed the mass to begin at the level of L5, continuing to the insertion of the iliopsoas muscle on the femur. Surgery was performed to remove the mass. The femoral ner...

Objective To assess the feasibility and safety of laparoscopic ovariectomy in guinea pigs utilizing 3‐mm minilaparoscopic instruments. Study design Experimental pilot study. Animals Guinea pigs (n = 3). Methods The guinea pigs were sedated, placed under general anesthesia, and intubated under endoscopic visualization. A 3‐port technique was used...

Objective: To assess histologic evaluation of mandibular lymph nodes (MLNs) and medial retropharyngeal lymph nodes (MRLNs) for metastatic disease during tumor staging for dogs with oral malignant melanoma (OMM) and oral squamous cell carcinoma (OSCC). Design: Retrospective multi-institutional study. Animals: 27 dogs with OMM and 21 dogs with O...

Table of means and standard deviations for each skull under each CT acquisition algorithm (bone vs standard) and at each software threshold setting (226HU and -650HU), including skull weights. (XLSX)

CFU vs. Roughness Data. Biofilm growth (CFU) per disk versus Ra and Rq using ln transform for CFU, Ra & Rq data (Table 3, Fig 5). (CSV)

CFU vs. Disk Data. Biofilm growth (CFU) per disk using ln transform for CFU data (Fig 3, Tables 1 and 2). (CSV)

STL file of 3D printed disk. (STL)

Roughness within Disk Data. Variance in Ra within disk using ln transform for Ra & Rq (Table 4). (CSV)

Background: Chylothorax is the accumulation of lymphatic fluid associated with molecules coming from digestion process (chyle) in the thorax. In this case report, we describe a canine patient with chylothorax that presented with an unusual clinical presentation: subcutaneous swelling due to chylous fluid leakage through the thoracic inlet. Case: A...

Canine osteosarcoma is a devastating disease with an overall poor prognosis. Radiation therapy and bisphosphonates are currently used in combination for palliative treatment, despite a paucity of literature that investigates their combined use. The objectives of this study were to assess the in vitro effects of radiation therapy and bisphosphonates...

Objective To evaluate the long‐term outcome of video‐assisted thoracoscopic (VATS) thoracic duct ligation (TDL) and pericardectomy for treatment of chylothorax in dogs. Study design Multi‐institutional retrospective study. Animals Thirty‐nine client‐owned dogs. Methods Dogs were included if they had undergone a VATS TDL and pericardectomy and ha...

Background: Osteosarcoma is the most common bone tumour in canines and in humans. Previous studies have shown that both tumour cells and tumour-associated cells can promote osteosarcoma progression through extracellular vesicle secretion, such as exosomes. Various factors within the environment, such oxygen level, overall pH and matrix stiffness, c...

This short case presentation is intended to describe and show video footage of preliminary experiences using the Storz SPIES video telescopic operating microscope (VITOM) II system for evaluation of sentinel lymph nodes (SLN) in dogs using indocyanine green (ICG) near infrared fluorescence imaging technology. Peritumoral 4 quadrant injection of ICG...

The emergence of rapid prototyping technology has allowed for the development of patient-specific implants and cutting guides to assist in both in the pre and intraoperative phases. Patient-specific rapid prototyped implants have been described for many applications in human patients including the correction of dental and maxillofacial deformitie...