Soft Tissue & Orthopedic Surgery

Below, please find links to all of the clinical trials involving soft tissue or orthopedic surgery. The studies include a multitude of information, including (but not limited to) the study’s purpose, benefits for participating, and financial incentive information. If you have any questions, please contact the individual outlined at the end of each trial summary.

Please visit the Surgery service webpage at the Veterinary Medical Teaching Hospital (VMTH) if you would like to learn more about the amazing things that our surgeons can do for you and your animal.


Hiatal Hernia / Brachycephalic Obstructor Syndrome: Assessing a Surgical Treatment

Title: Effect of Surgical Treatment of Brachycephalic Obstructor Syndrome on the Lower Esophageal Area of Brachycephalic Dogs with Evidence of Hiatal Herniation and Gastroesophageal Reflux

Purpose of Study: We believe that brachycephalic dogs have a tendency to develop hiatal herniation (HH) with greater frequency than non-brachycephalic dogs. Dogs with relative obstruction of the upper airways may generate a decreased pressure in their chest during inspiration (breathing in) that results in the upper part of the stomach being sucked into the chest (HH). This can lead to clinical signs including regurgitation, esophageal stricture formation and aspiration pneumonia if severe. We hypothesize that, if the upper airway obstruction in these dogs can be alleviated, improvement in their respiratory compromise might be seen as well as a reduction in the severity of their HH.

Participation Requirements:

  • Brachycephalic breed (dogs with broad short skulls)
  • No evidence of other upper airway obstructive pathology (especially tracheal collapse and hypoplastic trachea)
  • No previous brachycephalic surgery
  • Evidence of hiatal herniation on fluoroscopic imaging (performed pre-operatively)

Initial Evaluation for Participation: Initial evaluation and discussion for entry into the study can be arranged by making an appointment with our Internal Medicine or Soft Tissue Surgery or by contacting Dr. Phil Mayhew directly (contact information below).

Procedures: Both visits outlined below require hospitalization for 2-4 days at the VMTH.

  • First visit:
    • Day 1: You will be asked to fill out a questionnaire about your dog’s clinical signs. We will give your dog a local anesthetic, place a small catheter down your dogs nose, and give your dog a small amount of water to swallow, so we can trace the pressure profile of your dog’s esophagus (known as high-resolution manometry or HRM study). We will then perform a barium esophagram, which involves imaging of your dog using a fluoroscope (moving x-ray machine) after he/she swallows water and food boluses. Finally, we will place a small pH-monitoring probe in you dog’s nose that will remain in place for no longer than 24-hours for continuous monitoring of the esophageal pH and will be removed prior to surgery the following day.
    • Day 2: Your dog will be prepared for surgery and given general anesthesia. Prior to surgery, we will take measurements of your dog’s lower esophageal area (impedance planimetry or Endoflip), which involves inflation of a very low-pressure balloon within the lower esophagus, and perform an upper gastrointestinal endoscopic study immediately before upper airway surgery.
  • 30 – 60 days post-surgery visit: You will need to bring your dog in for another visit between 30 and 60 days after surgery. During this visit, we need to repeat the questionnaire and the procedures outlined above to gauge the response to surgery.

Benefits: The trial will pay for all of the diagnostic tests associated with the study, including costs associated with the HRM and esophagram studies, Endoflip measurements, pH impedance studies, endosocopic studies, biopsy procedures, pathology fees as well as the hospitalization and anesthesia fees associated with the second visit to the hospital at 30-60 days post-operatively. The owner will have to cover the surgical procedure, hospitalization and any possible complications associated with the surgical procedure and recovery during the first visit.

We cannot promise any benefits to your dog or other animals from your taking part in this clinical trial; however, possible benefits include a better understanding of your dogs presence or absence of hiatal herniation which may aid in longer-term management of this component of his or her clinical signs. Results from this study may influence treatment of other dogs with similar conditions going forward.

Owner Responsibilities: If you allow your dog to participate in this study, you will be responsible for bringing the dog to the VMTH for the study-related visits for the duration of the time stipulated and for providing the clinical information stipulated.


  • Please call (530) 752-1393 to make an appointment with Soft Tissue Surgery or Internal Medicine for Dr. Phil Mayhew's study
  • Email Dr. Phil Mayhew directly at
Imaging: Using New Imaging Techniques During Surgery

Title: Intraoperative Near-Infrared Fluorescent Imaging

Purpose of Study: Near-infrared fluorescent imaging utilizes light just out of the visual spectrum to generate additional imaging information in the treatment of a wide variety of diseases.  The near infrared light is generated by a special contrast agent (Indocyanine Green) that is injected into the patient.  When a near-infrared light source is used to illuminate the surgical site, any tissue in which this contrast agent is located will glow, aiding the surgeon in identifying the location or extent of disease.  Based on early experiments in rodents and human clinical trials, this very sensitive tool has the potential to improve surgical decision-making and improve overall treatment for a wide variety of diseases including various tumors, sentinel lymph node identification, assessing viability of skin flaps, identification of liver shunts, identification of urinary tract obstruction or trauma, identification of bilary tract obstruction or trauma, assessment of gastrointestinal perfusion, and treatment of difficult wounds.  The purpose of this study is to evaluate the efficacy of this imaging modality in veterinary patients presenting with natural disease processes.

Participation Requirements: Dogs scheduled for surgery.

Initial Evaluation for Participation: Evaluation by Dr. Michele Steffey on the Soft Tissue Surgery Service.

Procedures: Indocyanine Green will be administered, either subcutaneously or intravenously, at a dose and timing considered to be optimal by your attending veterinarian.

Benefits: There may or may not be a specific benefit to your dog by participating in this study.  Use of Indocyanine Green may or may not aid in the intraoperative decision-making by the veterinary surgeon.

Owner Responsibilities: If an allergic reaction should occur, immediate costs of treatment (diphenhydramine, support of blood pressure) will be covered by the study; however, the owner will be responsible for any treatment costs for prolonged or severe complications.

Contact: Call the scheduling coordinators in Soft Tissue Surgery at (530) 752-1393 for Dr. Steffey's study.

Intrahepatic Portosystemic Shunts: Assessing a New Treatment Technique

Title: Assessment of Outcome in Dogs Undergoing Percutaneous Transvenous Coil Embolization to Treat Intrahepatic Portosystemic Shunts

Purpose of Study: The purposes of this project are to:

  1. Evaluate serum bile acid concentrations and hepatic biochemical functional parameters (BUN, albumin, cholesterol, glucose, and bilirubin) in dogs with intrahepatic portosystemic shunts both pre- and post-treatment to objectively evaluate each patient for improvement in hepatic function.
  2. Assess the improvement in the clinical signs of dogs with IHPSS after the performance of PTCE.
  3. To perform imaging studies pre- and post-PTCE that provide objective assessment of outcome associated with the PTCE procedure.

Participation Requirements: Dogs with intrahepatic portosystemic shunts

Initial Evaluation for Participation: Contact Dr. Culp for details at or (530) 752-1393.

Procedures: Dogs with a diagnosis of intrahepatic portosystemic shunts (IHPSS) will be enrolled in the study. The dog will undergo percutanous transvenous coil embolization (PTCE) to treat his/her IHPSS. Prior to and after this procedure, diagnostics including bloodwork, nuclear scintigraphy, abdominal ultrasound and computed tomography (CT) scan will be performed and compared.

Benefits: Enrolling a dog in this study results in a significant financial incentive towards diagnostics that would be recommended for the dog whether or not he/she is enrolled in the study. This benefit includes payment of the preoperative CT scan and the postoperative bloodwork (1 chemistry panel at 3 months postoperative), ultrasound (1 at 3 months postoperative), nuclear scintigraphy scan (1 at 3 months postoperative) and CT scan (1 at 3 months postoperative).

Owner Responsibilities: Return the patient 3 months after treatment for further assessment.

Contact: Contact Dr. Culp for details at or (530) 752-1393.

Large Bowel Disease: Evaluating a New Diagnostic Tool

Title: Evaluation of CT pneumocolonography as a diagnostic tool in veterinary patients

Purpose of Study: The purpose of this study is to evaluate the impact of imaging findings on surgical decision-making in dogs with colonic and rectal disease of any kind (cancer or non-cancer). This part of the body can be a very difficult region examine with current imaging methods, which also do not provide optimal spatial information important if a surgical procedure is needed. In early studies, we have demonstrated the safety and efficacy of the CT pneumocolonography procedure in normal dogs, but it is important that we learn to accurately interpret the imaging findings for a wide variety of disease processes in clinical patients so that our CT diagnoses are accurate. Our goal is to compare the imaging findings obtained with CT pneumocolonography with the current standard of care of colonoscopy and colonoscopic biopsies.

Participation Requirements: In order to participate in this study, a colonoscopic exam must have been recommended for workup of your dog’s problem, and your dog must be scheduled to receive a colonoscopic exam under general anesthesia at UC Davis.

Initial Evaluation for Participation: None.

Procedures: If you agree to participate, your dog will receive a CT scan (with and without intravenous contrast material) in conjunction with carbon dioxide gas insufflated into the rectal lumen. Following CT pneumocolonography, your dog will receive the scheduled colonoscopy, which is the current standard of care for assessment of these masses, and if clinically indicated for the care of your dog, biopsies will be obtained.

Benefits: In return for participation in this study, your dog will receive a free CT scan (an approximately $800 value to you), which may directly benefit your dog, as it can provide important information for treatment recommendations that other types of imaging cannot. CT evaluation of local lymph nodes is an additional benefit as CT has been demonstrated to be helpful in the evaluation of regional lymph nodes for metastatic disease in other types of cancer in other locations.

Owner Responsibilities: There is no additional cost to you for your dog’s participation in the study. You are financially responsible for hospital costs associated with the standard care of your dog, including abdominal ultrasound, general anesthesia, colonoscopy, hospitalization, biopsies, and any other diagnostic tests recommended for evaluation of your dog’s disease by your attending clinician.

Contact: Call 530-752-1393 for Drs. Michele Steffey and Stanley Marks's study