Tibial Apophyseal Percutaneous Pinning in Skeletally Immature Dogs: 25 Cases (2016-2019).

OBJECTIVE: The aim of this study was to report the clinical experience with fluoroscopically guided tibial apophyseal percutaneous pinning (TAPP) for tibial tuberosity avulsion fractures (TTAF). STUDY DESIGN: This is a retrospective case series. MATERIALS AND METHODS: Medical records of skeletally immature dogs (n = 25) were reviewed. The association of pin design [smooth (SP); negatively threaded (NTP)], pin insertion angles, TTAF-type, age and breed with various outcome variables was statistically evaluated. Long-term follow-up was assessed via direct examination, radiographs, questionnaires and videos. RESULTS: Mean age, weight and surgery times were 6.2 months, 9.6 kg and 21 minutes respectively. No major complications occurred among the 19 SP and 6 NTP; no pin broke. Seromas and patellar desmitis rates were higher with SP (11/19; 16/19) versus NTP (0/6; 2/6) (p = 0.02; 0.03). The median horizontal pin cross angles for cases without and with desmitis were 40 and 26 degrees respectively (p = 0.047). Explantation was needed in 5/19 SP and 0/6 NTP cases. The mean tibial plateau angle (TPA) changed significantly between initial (25.6 degrees) and follow-up (18.8 degrees) radiographs (p = 0.0002). Long-term outcome, obtained at a mean of 19.9 months, was excellent in all cases. CONCLUSION: Tibial apophyseal percutaneous pinning can be considered to treat TTAF. Divergent pin placement and using NTP might reduce complications. Tibial plateau angle should be monitored until skeletal maturity has been reached. Long-term outcome post TAPP can be expected to be excellent.

Interventional Therapies of the Urinary Tract.

Minimally invasive interventional therapies are the new standard of care in veterinary medicine. In comparison with standard surgical procedures, they are associated with minimal tissue injury, leading to shorter, smoother recovery and decreasing the perioperative morbidity and mortality. A thorough understanding of the therapeutic options available is essential to properly educate and inform clients. Proper equipment, technical expertise, and experience are essential prerequisites to many of these procedures.

Interventional Equipment and Radiation Safety.

Interventional radiology in veterinary medicine was adapted from techniques developed in human medicine, and has a variety of applications to treat disease in multiple body systems. Fluoroscopy is required for almost all interventional procedures, requiring knowledge of proper safety techniques for working with ionizing radiation. There are a wide variety of catheters, wires, sheaths, stents, and embolics used in veterinary medicine. Familiarity with their indications and sizing compatibility is essential for procedural success.

Interventional Closure of a Patent Ductus Arteriosus Using an Amplatz Canine Duct Occluder in an Alpaca Cria.

A 6-month old female alpaca cria presented to The Ohio State University for evaluation of a cardiac murmur. Echocardiography revealed a left-to-right shunting patent ductus arteriosus, a restrictive left-to-right shunting perimembranous ventricular septal defect, and secondary moderate left atrial and ventricular dilation. Aortic root angiography demonstrated a type IIA patent ductus arteriosus (PDA). Interventional closure of the PDA was successfully performed, without complication, using an Amplatz canine duct occluder. This case report describes the materials and methods used for interventional closure of a PDA in an alpaca cria.

Surgical retrieval of a guide wire lost during central venous catheterization in a dog.

OBJECTIVE: To report a case of successful surgical removal of a guide wire lost during central venous catheterization. CASE SUMMARY: A 28 kg, 4-year-old female neutered mixed breed dog presented to the primary care veterinarian with diabetic ketosis. During the process of central venous catheterization, the guide wire was accidently released and the entire length of the guide wire slipped into the jugular vein. Due to the absence of nearby interventional radiology facilities, surgical intervention was proposed. An ultrasound was used to determine that the guide wire was located in the caudal vena cava extending caudally into the right internal iliac vein. Rommel tourniquets were placed around the iliac vein cranial to the bifurcation of the common iliac vein into the external and internal iliac veins. A venotomy was performed in the right common iliac vein and the guide wire was grasped with hemostats and gently removed while alternately relaxing the cranial then caudal tourniquets. During anesthesia, ventricular premature contractions were noted that varied in frequency with the dog's positioning. Postoperative color flow Doppler ultrasound evaluation of the caudal vena cava, right common, internal and external iliac veins, and right femoral vein was normal with no evidence of thrombosis. Several days postoperative the dog's diabetic ketosis and ventricular premature contractions had resolved and color flow Doppler ultrasound evaluation was normal with no evidence of thrombosis. NEW OR UNIQUE INFORMATION PROVIDED: To the authors' knowledge, this is the first reported veterinary case of loss and subsequent surgical retrieval of a central venous catheter guide wire.

Development and characterization of a technique for percutaneous radiologic gastrojejunostomy tube placement in the dog.

OBJECTIVE: To develop and describe a technique for percutaneous radiologic gastrojejunostomy tube placement in the dog. DESIGN: Prospective technique development study. SETTING: University teaching hospital. ANIMALS: Six healthy adult male Beagles. INTERVENTIONS: Following anesthetic induction, fluoroscopic and ultrasound guidance were used to identify an appropriate gastropexy site on the left lateral abdomen. Gastropexy was performed using gastrointestinal suture anchors. An over-the-wire catheter technique using fluoroscopic guidance was used to achieve jejunal access. An 18F/8F, 58 cm, dual-lumen gastrojejunal feeding tube was placed via serial over-the-wire dilation of the body wall using an 18F peel-away introducer kit. Tube location was determined radiographically immediately following placement and on days 2, 4, after emesis on day 4, and at time of gastrojejunal feeding tube removal (day 16-18). MEASUREMENTS AND MAIN RESULTS: Percutaneous radiologic gastrojejunostomy (PRGJ) tube placement was successful in all dogs. Median time to pyloric passage with the guide wire was 23.5 minutes (range, 9-93 minutes). Median total procedure time was 53 minutes (range, 49-113 minutes). Significant tube migration was not observed at any point during the study. One dog developed linear foreign body obstruction secondary to the tube on day 5 that was relieved by release of the jejunal component. Other complications were minor and included mild-to-moderate peristomal inflammation in all dogs and removal of the feeding tube on day 3 by 1 dog. Feedings were well tolerated in all dogs. CONCLUSIONS: PRGJ tube placement in the dog is a safe and minimally invasive technique that allows for jejunal feeding without surgery or endoscopy. The high success rates, acceptable procedural times, and minimal complications are appealing for use in critically ill patients. Although additional evaluations are needed, PRGJ tube placement may be considered for dogs that require postpyloric feeding with or without gastric decompression.

Arthroscopic Removal of Large Extensor Process Fragments in 18 Friesian Horses: Long-Term Clinical Outcome and Radiological Follow-Up of the Distal Interphalangeal Joint.

OBJECTIVE: Report long-term clinical and radiological follow-up in horses after removal of large extensor process fragments occupying >25% of the joint surface of the distal interphalangeal joint (DIJ). STUDY DESIGN: Retrospective case series. ANIMALS: Friesian horses (n=18) that underwent arthroscopic removal of a large extensor process fragment. METHODS: Arthroscopic examination of the DIJ was performed in dorsal recumbency with the affected foot in extension using routine portals. Visualization of the fragment was improved using motorized synovial resectors. A dissection plane between the common digital extensor tendon and the extensor process fragment was created using sharp lever instruments, in some cases aided by motorized burrs and radiofrequency ligament dissection. The fragment was removed piecemeal using Ferris-Smith rongeurs. Medical records, preoperative and postoperative radiographs, and owner surveys were reviewed for case details and outcome. RESULTS: The technique described allowed removal of the large fragment in all 18 horses. Of the 17 horses where long-term clinical follow-up was available, 14 were used as intended and 3 kept some degree of lameness. The angle between the remodeled extensor process and the dorsal surface of the distal phalanx was increased and subchondral bone remodeling at the fragment bed was noted on postoperative lateromedial radiographs. CONCLUSION: Arthroscopic removal is a good treatment option for horses with large extensor process fragmentation with a good long-term outcome. Remodeling of the remaining extensor process and the subchondral new bone formation in the fragment bed can occur with functional recovery.

Description and Biomechanical Comparison of a Percutaneous Radiologic Gastropexy Technique in a Canine Cadaver Model.

OBJECTIVE: To describe a novel percutaneous radiologic gastropexy (PRG) technique in a canine model and to biomechanically compare this technique to open incisional gastropexy (OIG) and laparoscopic-assisted incisional gastropexy (LAG). STUDY DESIGN: Randomized ex vivo biomechanical study. ANIMALS: Canine cadavers. METHODS: Fifteen cadavers were randomized to 1 of 3 surgical interventions: OIG, LAG, and PRG. For the PRG procedure, the stomach was distended with air, and a preloaded T-fastener device was utilized to attach the stomach to the body wall with fluoroscopic-guidance. The procedural times of the 3 techniques were recorded. After completion of the procedure, the stomach and body wall overlying the stomach wall were harvested and the maximum tensile strength of the gastropexies was determined. RESULTS: The maximal tensile strength was not significantly different between groups. The total procedural time for the PRG procedure (5 minutes) was significantly shorter than both OIG (28 minutes) and LAG (20 minutes) procedures. CONCLUSION: The PRG technique described in this study demonstrated a similar maximal tensile strength to commonly employed gastropexy techniques (OIG and LAG) in an acute canine model. Additionally, the PRG procedure was significantly faster to perform. The clinical relevance of this technique will be determined by further study to assess the applicability and efficacy of this procedure in clinical patients by determining the likelihood of adhesion development and the ability of the adhesion to prevent gastric volvulus.

Efficacy of Two Radiologic-Assisted Prophylactic Gastropexy Techniques.

OBJECTIVE: To describe the technique and clinical outcome of prophylactic percutaneous radiologic-assisted gastropexy (PRG) and radiologic-assisted incisional gastropexy (RIG) in client-owned dogs. STUDY DESIGN: Prospective, nonrandomized clinical trial. ANIMALS: Fourteen client-owned, large, and giant breed dogs. METHODS: Four dogs underwent PRG with fluoroscopic guidance to place 2 T-fasteners into the pyloric antrum and secure it to the right body wall. Ten dogs underwent RIG, which was a modification of PRG. For RIG, the T-fasteners were first used to approximate the pyloric antrum and body wall, then a full thickness incision through the body wall was made and the pyloric antrum was sutured to the internal abdominal wall. The duration and complications of each procedure were recorded. The gastropexy was assessed by abdominal ultrasound at day 1, week 2, and week 8 postoperative and by barium gastrogram at week 8 postoperative. RESULTS: No dogs undergoing PRG had a gastropexy present at week 2. All dogs undergoing RIG had ultrasonographic evidence of gastropexy at day 1, week 2, and week 8 postoperative. Gastrograms in 9/9 dogs were consistent with an intact gastropexy, appropriate gastric positioning and appropriate gastric emptying began. No major complications were noted. CONCLUSION: The PRG was unsatisfactory and did not result in a permanent gastropexy. The RIG was safe and created a gastropexy that remained intact at 8 weeks postoperative. The RIG should be considered as a minimally invasive option for prophylactic gastropexy in dogs of at-risk breeds.

Interventional Radiology of the Urinary Tract.

Minimally invasive treatment options using interventional radiology and interventional endoscopy for urologic disease have become more common over the past decade in veterinary medicine. Urinary tract obstructions and urinary incontinence are the most common reasons for urinary interventions. Ureteral obstructions are underdiagnosed and a common clinical problem in veterinary medicine. Ureteral obstructions should be considered an emergency, and decompression should be performed as quickly as possible. Diagnostic imaging is the mainstay in diagnosing a ureteral obstruction and has changed in the last few years, with ultrasound and radiographs being the most sensitive tools in making this diagnosis preoperatively.

Interventional Radiology: Equipment and Techniques.

The breadth of small animal diseases that can now be treated by a minimally invasive, transcatheter approach continues to expand. Interventional radiology is the field of medicine that affects a therapeutic outcome via minimally invasive catheterization of peripheral blood vessels or body orifices guided by imaging. The intent of this article is to provide an overview of the equipment required for interventional radiology in veterinary medicine with a discussion of technical uses in diseases of dogs and cats.

Interventional Oncology.

The approach to the treatment of cancer in veterinary patients is constantly evolving. Whenever possible and practical, surgery is pursued because it provides the greatest opportunity for tumor control and may result in a cure. Other cancer treatments, such as chemotherapy and radiation therapy, are commonplace in veterinary medicine, and the data outlining treatment regimens are growing rapidly. An absence of treatment options for veterinary cancer patients, however, has historically existed for some tumors. Interventional oncology options have opened the door to the potential for better therapeutic response and improved patient quality of life.

Dispersal pattern of injectate following CT-guided perineural infiltration in the canine thoracolumbar spine: a cadaver study.

An increasing proportion of canine patients are presented with chronic thoracolumbar back pain and without compressive spinal lesions. In humans, spinal perineural infiltrations have been reported to have a favorable effect on pain control. The purpose of this prospective cadaver study was to describe the dispersal pattern of injectate following CT-guided spinal perineural infiltration in the canine thoracolumbar region. Seven fresh canine cadavers were first scanned using multislice CT and then CT-guided spinal perineural infiltration was performed at 42 sites from T13/L1 to L6/L7. The injectate for each site was a mixture of new methylene blue and iodinated contrast medium. Immediately following CT-guided injection, cadavers were frozen, cut, and dissected macro- and mesoscopically (using a magnifying glass) to identify anatomic structures that were infiltrated. In the majority of sites (64.3%), complete epidural and hypaxial staining of spinal nerve components (including the spinal ganglion, trunk, and ventral branch) was successfully achieved. However, no (11.9%) or unpredictable staining (9.5%) of nervous tissue occurred in some sites despite careful CT guidance and the application of relatively large volumes of injectate. Optimal results were achieved when the needle tip was positioned periforaminally ventral to the cranial contour of the cranial articular process. Findings from this ex vivo study indicated that CT-guided spinal perineural infiltration is feasible for testing in the canine thoracolumbar region and that successful nerve tissue infiltration would likely occur in the majority of sites. Future in vivo studies are needed to determine the safety and efficacy of this technique.

Computed tomography assisted determination of optimal insertion points and bone corridors for transverse implant placement in the feline tarsus and metatarsus.

OBJECTIVE: Describe optimal corridors for mediolateral or lateromedial implant placement in the feline tarsus and base of the metatarsus. METHODS: Computed tomographic images of 20 cadaveric tarsi were used to define optimal talocalcaneal, centroquartal, distal tarsal, and metatarsal corridors characterized by medial and lateral insertion points (IP), mean height, width, length and optimal dorsomedial-plantarolateral implantation angle (OIA). RESULTS: Talocalcaneal level: The IP were at the head of the talus and plantar to the peroneal tubercle of the calcaneus and OIA was 22.7° ± 0.3. Centroquartal level: The IP were at the centre of the medial surface of the central tarsal bone and dorsoproximal to the tuberosity of the fourth tarsal bone and OIA was 5.9° ± 0.06. Distal tarsal level: The IP were at the centre of the medial surface of the tarsal bone II and dorsodistal to the tuberosity of the fourth tarsal bone and OIA was 5.4° ± 0.14. Metatarsal level: The IP were at the dorsomedial surface of the proximal end of the metatarsal bone II and at the dorsolateral surface of metatarsal bone V and OIA was 0.5° ± 0.06. Significant positive correlation was found between body weight and the length of each corridor. CLINICAL SIGNIFICANCE: Most of the corridors obtained in this study had a diameter between 1.5 mm and 2 mm with a length of 15 mm to 18 mm, which stresses the importance of their accurate placement.

C-arm fluoroscopy for the removal of an intraorbital foreign body in a cat.

This report describes the clinical manifestations, diagnosis and minimally surgical intervention of a cat with an intraorbital foreign body. A spayed female cat of unknown age was presented with a recurrent cutaneous sinus tract of the left suborbital region. The cat had not vocalized at all since the adoption. A sharp-edged radiopaque foreign body was visualized on dental radiography. Computed tomography outlined the length of the foreign body from the intraorbital soft tissue to the pharynx. The foreign body was removed under the guide of C-arm fluoroscope with minimal skin incision. The surgical site healed completely on the 11th postoperative day, and the cat vocalized normally after healing.

Basic investigation of vascular interventional radiology (IR) using large rabbits.

The purpose of this study was to determine the usefulness of large rabbits for basic vascular interventional radiology (IR) experiments. We used 5 Akita large rabbits (Akita) and 5 Japanese white rabbits (JW). We conducted measurements of vessel diameters such as the aorta, and the iliac, renal, superior mesenteric, celiac, and proper hepatic arteries, and of the growth rates of VX2 liver tumors. There were significant differences between Akita and JW in the diameters of the thoracic aorta, lower abdominal aorta, and celiac artery. In other blood vessels, no significant differences were found. There was no difference in the growth rates of the VX2 tumors between Akita and JW. The possibility that Akita large rabbits could be utilized for vascular IR was demonstrated.

Computed tomography-guided fine-needle aspirate and tissue-core biopsy of intrathoracic lesions in thirty dogs and cats.

Medical records and computed tomography (CT) images were reviewed retrospectively for 30 animals (27 dogs, two cats, one cougar) in which CT-guided intrathoracic fine-needle aspirates (FNA) (12), core biopsies (10) or both (8) were performed. Sample interpretation was listed as diagnostic or nondiagnostic and nonneoplasia or neoplasia. Diagnostic results were inconclusive in 35% FNA and 17% biopsies. FNA and biopsy interpretations were in agreement in seven patients, one nonneoplasia, and six neoplasia. A clinical diagnosis was made in 65% FNA and 83% biopsies. When 18 patients with confirmed diagnoses were used, overall accuracy for diagnosis was 92% for FNA and biopsy and the sensitivity for neoplasia was 91% using fine needle aspirate and 80% using biopsy. Complications seen on CT images were noted in 43% of patients, four pneumothorax, five pulmonary hemorrhage, and four with both. No clinical manifestations were noted and treatment was not necessary. Significant correlation was noted between complications and penetration of aerated lung, but not with lesion location, type of disease, method of sampling, width of mass and depth of aerated lung penetrated. CT-guided sampling is relatively safe and useful in the diagnosis of intra-thoracic lesions, especially neoplasia. FNA samples are nondiagnostic more often than biopsy samples. Sub-clinical pneumothorax and hemorrhage are common when aerated lung is penetrated.

Treatment of 10 dogs with discospondylitis by fluoroscopy-guided percutaneous discectomy.

Ten dogs suffering from discospondylitis were treated by percutaneous discectomy and local and systemic antibiotic therapy. With fluoroscopic guidance, a cylinder 5 mm in diameter was removed from the centre of the intervertebral space, yielding a fenestration and decompressing the disc without producing any spinal instability. The causative bacteria were identified in nine of the 10 biopsy specimens, but in only three urine cultures and four blood cultures. In two cases, the antibiotics used initially had to be changed owing to the organisms' antibiotic resistance. The clinical signs of the dogs improved markedly after two to nine days (mean 4.2 days) and had resolved completely after five to 14 days (mean 9.1 days). In all the cases the disease could be classified histologically as either acute or chronic, and the disease was classified as chronic in one dog. No side effects were observed.

Computed tomography-guided fine-needle aspiration and tissue-core biopsy of bone lesions in small animals.

In humans, free-hand computed tomography (CT)-guided biopsy is an accurate method to obtain a tissue sample. There are only a few reports of this technique in veterinary medicine. In the present study, 21 dogs and two cats underwent a free-hand CT-guided tissue-core biopsy (17 animals) or fine-needle aspiration (six animals) of a bone lesion. Two out of 17 tissue-core samples were also cultured. All 17 tissue-core biopsy samples were diagnostic (accuracy of 100%). Five out of six aspirates were diagnostic (accuracy of 83.3%). The overall accuracy was 95.7%. In one aspirate, cytologic quality was insufficient containing only blood. No major complications were encountered. Fourteen neoplastic, two infectious and six benign lesions were diagnosed. CT examination after intravenous contrast medium added useful information to avoid large vessels and to biopsy-viable tissue. Free-hand CT-guided tissue-core biopsy and aspiration appears to be a safe and very accurate procedure for use in the diagnosis of bone-associated diseases in small animals.