Interventional Radiology
Interventional radiology enables treatment of internal body structures without the need for invasive surgery.
What is interventional radiology and endoscopy?
Interventional Radiology (IR) and Endoscopy (IE) involves the use of sophisticated imaging techniques such as fluoroscopy, bronchoscopy and cystoscopy. The main advantages of IR/IE are primarily due to the shorter duration of recovery time, reduced complications and lower mortality rate compared to many of the traditional surgical options.
Many of the techniques that are proving successful in veterinary IR/IE have developed because a good traditional treatment for the underlying condition may not currently exist. The use of IR/IE therefore enables us to achieve improved clinical outcomes for patients for conditions which had previously proved challenging or treat with conventional surgery. The techniques are technically challenging and require access to specialist equipment and training.
Interventional radiology and endoscopy enables us to achieve improved outcomes for patients for conditions which had previously proved challenging to treat with conventional surgery.
Common interventional procedures
Respiratory procedures
Stents are placed to relieve an obstruction to a tubular structure. This obstruction may be due to a physical object such as a kidney or bladder stone, or may be a consequence of injury, degeneration or from abnormal development of the affected body part. Metallic stents are made of a highly-flexible material called nitinol (nickel-titanium); these types of stents are self-expanding. Other stents are made of silicone or polyurethane.
Stents are placed to relieve an obstruction to a tubular structure.
In our patients, stents can be used to manage cases of tracheal collapse, nasopharyngeal stenosis, urinary tract obstruction (ureteral or urethral) or blood vessels.
Video showing management of tracheal collapse and nasopharyngeal collapse with a stent
Small endoscopes provide full colour, magnified images of the internal structures of the lower urinary tract, and permit many treatments to be completed without the need for invasive surgery.
A surgical laser is used to remove the thin wall that separates the ectopic ureter (bottom ) from the urethra (top)
Urinary tract procedures
Many diseases of the urinary tract can be successfully investigated or treated with interventional radiology and endoscopic techniques. Some specific examples include:
Incontinence: There are many possible causes for incontinence in the dog, but an endoscopic examination is considered the gold-standard to assist with diagnosis. Many anatomical causes of incontinence such as ectopic ureters or persistent vaginal remnants can be corrected using laser with endoscopic guidance.
Urinary obstruction: Difficulties with urination may occur due to obstruction of the outflow from the bladder by stones, tumours or other physical obstructions. Following diagnosis, we can remove most bladder and urethral stones via key-hole surgery (percutaneous cystolithotomy), or manage strictures or tumours by placement of a stent. SUBS:
Bladder & prostate tumours: Tumours arising from the bladder, prostate or urethra can be challenging to treat. The team at AURA have pioneered a number of new treatments, including laser resection of focal bladder tumours or embolisation of prostate tumours.
Gastrointestinal interventions
The gastrointestinal tract is an ideal organ for examination by endoscopy as many parts cannot otherwise be fully examined without invasive surgery. Using a range of flexible endoscopes, our interventional team can perform a visual inspection of the upper intestinal tract (including oesophagus, stomach and upper small bowel) or the low bowel. Biopsies and samples from the lining of the bowel can be collected for microscopic examination to assist with disease diagnosis. Other specific gastrointestinal conditions that can be address include:
Oesophageal strictures: Scarring of the oesophagus (food pipe) can occur following obstruction with a foreign body, but is also recognised as a rare complication of acid reflux during anaesthesia. Oesophageal strictures are complicated to manage, but many patients can be treated successfully using either repeated balloon-dilation or placement of a temporary stent.
Feeding tube placement: Maintaining a good intake of quality food is essential if the patient is to have the ability to fight their disease successfully, or if they are able to cope with the temporary functional loss due to surgery. In these cases, a feeding tube can be placed into the oesophagus or stomach, to allow the patient to be fed. If necessary, some patients can usually be managed at home with a feeding tube. Family members are provided with all of the training needed to manage the feeding tube while it is in place.
Many foreign bodies in the oesophagus or stomach can also be removed using the endoscope, thus avoiding the need for invasive surgery.
Video showing balloon dilation of an oesophageal stricture
If the abnormal shunt vessel can be closed, patients can usually enjoy a normal life.
Video showing a CT of a dog with a large right-sided intrahepatic portosystemic shunt (highlighted). For management, a metal stent is placed into the vena cava, and then a number of small vascular coils are placed into the shunt to cause obstruction of this abnormal blood flow. The metal stent acts as a barrrier, and prevents the coils from passing into the general circulation.
Hepatobiliary (liver) interventions
The Interventional Radiology team manage a number of specific liver conditions including:
Liver shunts and arteriovenous malformations: The liver has a complicated anatomy, and it is not unusual for some patients to be born with defects to the normal structure, including shunts and arteriovenous malformations. Patients with liver shunts have been born with an abnormal development of the blood supply to the liver. Blood from the intestinal tract is then shunted directly into the general circulation before it can be detoxified by the liver. However, some shunts are buried deep within the liver and closure with conventional surgery is complicated and risky. At AURA, these shunts are managed by a technique known as Percutaneous Transjugular Coil Embolisation (PTCE). With this technique, access to the abnormal vessel is achieved via a small incision in the neck to allow small plugs that encourage a clot to form in the vessel. Blood flow through this abnormal shunt vessel is then permanently blocked.
Bile duct obstruction: Blockage of the bile duct due to inflammation or gall stones can cause severe illness. Affected patients may have stopped eating, and may have a history of vomiting or have obvious jaundice. In early cases, clearance of the obstruction may be achieved by flushing of the bile duct, or by placing a stent using an endoscope or by percutaneous ultrasound guidance. These procedures are performed without the need for a complicated open surgery, but are only applicable for certain patients.
Liver tumours: For most solitary tumours of the liver, the surgical team will usually carefully review the patient to determine if they are a suitable candidate for surgery. When the risk of surgery is considered too great, the interventional radiology team may be able to provide some control of the tumour by blocking off, or embolising, the blood supply to the tumour. While this technique may not eliminate the tumour, embolisation can cause cessation of tumour growth and elimination of the clinical signs. The treatment can be repeated if necessary.
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