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Southpaws Newsletter 13th August, 2015

Moorabbin - Camberwell - Pt Cook 
p: (03) 9553 1775  f: (03) 8677 7630
e: info@southpaws.com.au
w: www.southpaws.com.au
In this edition:
  • Surgical Management of Pituitary Dependent Cushing’s Disease?
  • Is this a Curable Tumour?
  • New options for the challenge of elbow dysplasia
  • Links to our social media including YouTube surgical videos

Surgical Management of Pituitary Dependent Cushing’s Disease?

At Science Week this July, an interesting lecture was presented by Dr. David Church from the Royal Veterinary College. In this lecture, he suggested that a case can be made for the surgical treatment of all patients with Cushing’s disease. Obviously patients with adrenal tumours should be treated with surgery. Success rates of greater than 90% have been published even in patients with invasion of the vena cava. At Southpaws, we have treated nearly 100 patients with non-vena cava invading tumours with perioperative mortality approaching zero. In patients with vena cava invasion, our mortality rates are approximately 15%. 
Perhaps less obviously, the case was made by Dr. Church that patients with pituitary dependent Cushing’s disease could be treated with bilateral adrenalectomies. These patients become hypoadrenocortisolaemic and can be managed with medical supplementation. Dr. Church argues that the treatment is much easier than the management of Cushing’s disease with Trilostane or Mitotane. These treatments are ineffective in about 15-25% of patients. 

Surgical management with bilateral adrenalectomy can also be less expensive in the long-run. Coming from an internal medicine specialist and especially one as well-known and reputable as Dr. Church, adds weight to this recommendation. Bilateral adrenalectomy in dogs without adrenal tumours is very straightforward, with few operative complications.


 

Is this a Curable Tumour?

 

You Bet!!!

When treating this patient with a large tumour on the dorsum of the carpus, the first step was to make a diagnosis. 
The biopsy revealed a Grade II soft tissue sarcoma. The next step was staging. Thoracic radiographs and lymph node assessment were both negative for metastasis. About 20% of soft tissue sarcomas will eventually metastasise and the risk is grade-dependent. Grade I and II tumours spread in about 10% of cases. Grade III tumours spread in about 50% of cases. We have rarely, if ever, seen tumours which occurred below the knee or the elbow metastasise. Kuntz et al showed that these tumours are significantly less malignant than those occurring on the trunk. Chemotherapy has not been shown to reduce metastasis of soft tissue sarcomas. 

Treatment options in this patient include:

  • Marginal excision with primary closure - is associated with a relatively high local recurrence rate due to residual tumour cells in the patient. The rate of local recurrence ranges from 10% to 100% depending on the study and the grade of the tumour. Consensus would suggest about a 30% risk of recurrence.
  • Marginal excision followed by radiation therapy - results in reduction in local recurrence. Unfortunately, no prospective controlled studies have been performed. Previous studies assessing the benefit of radiation therapy have all used historical controls. Recurrence rate for this method is about 20%. Radiation therapy is available at Southpaws and the radiation therapy modality we have is completely appropriate for this type of tumour. 
  • Marginal excision followed by metronomic chemotherapy - in a study by Robin Elmslie, a significant reduction in local recurrence was demonstrated in dogs with marginally excised soft tissue sarcomas. Interestingly, dogs in the control group which did not receive metronomic chemotherapy had a 100% local recurrence rate. This is not what most other surgeons have observed and calls into question the validity of the study. Patients received a combination of piroxicam and cyclophosphamide. Significant side effects were noted in 8% of patients and consisted primarily of hemorrhagic cystitis which resolved upon discontinuation of cyclophosphamide in most patients. The published rate of local recurrence was about 20%, very similar to what is seen with postoperative radiation therapy. 
  • Wide local excision with second intention healing - this is the standard approach to date at Southpaws. We published 31 cases which occurred in the extremities in this fashion. We achieved clean margins in 100% of patients and had NO RECURRENCES at the completion of the study. This represents the lowest recurrence rate ever published in the veterinary literature for the treatment of soft tissue sarcomas. 29/31 patients healed completely without the need for a skin graft. 
  • Wide local excision with skin graft at the time of surgery and portable vacuum-assisted closure. This approach was presented at Science Week this year. The authors reported 100% graft survival. While we have not attempted this method, we have the portable pumps in stock and this will likely become the standard-of-care in the future in our facility. This offers the advantage of only needing bandage changes for 2 weeks following surgery. 
Above - Pico disposable pump for vacuum assisted closure.
Following treatment, surgical margins should be assessed and if incomplete, options should be discussed with the owners. 
As seen above, this patient was treated with wide local excision, the wound was left to heal by second intention. A skin graft was not possible even with vacuum-assisted closure because of the presence of bone instead of muscle as a graft-recipient surface. In this patient, the extensor tendons served as the deep margin. Tendon sheaths generally serve very well as a barrier to tumour penetration in this location. 
Margins were complete and this patient is well on its way to complete healing. Bandages are changed every 3 days until granulation tissue forms, then every 5-6 days. Complete healing generally takes about 8-10 weeks. Owners are very accepting of this treatment plan as long as they are informed prior to surgery. 

New options for the challenge of elbow dysplasia

James Simcock 
BVSc (hons), MANZCVS (Internal Medicine)
Diplomate ACVS- SA
Registered Specialist in Small Animal Surgery 

Introduction:

One of the most common causes of thoracic limb lameness in dogs, especially large breed dogs, is elbow dysplasia and its resultant osteoarthritis. Elbow dysplasia is one of the most challenging diseases that we manage with respect to diagnosis and particularly treatment. As a profession, we don’t have a clear consensus on the best way to manage this condition. In fact if you were to survey all of the surgeons in Australia, they would all likely have a different opinions on what is the best treatment for a particular patient at a given time. 

One of the biggest issues is that even with aggressive medical and surgical intervention there is invariably continued progression of osteoarthritis. Progressive osteoarthritis in the face of surgical and medical treatment has lead to the development of a multitude of new surgical procedures. Some of these are aimed at unloading the medial compartment of the joint including Proximal Abducting Ulnar Osteotomy (PAUL) and Sliding Humeral Osteotomy (SHO). Some are aimed at resurfacing or replacing the joint; Canine Unicompartmental Elbow replacement (CUE) and the various total elbow replacement systems. 

Components of Elbow Dysplasia:

Conditions recognised under the umbrella of elbow dysplasia include:
  • Fragmented medial coronoid disease (FMCP)
  • Osteochondritis Dissecans (OCD)
  • Ununited Anconeal Process (UAP)
  • Incongruence between the radius and ulna or possibly the humerus and ulna. 
These individual conditions can occur in isolation or in any combination. Incongruence is a relatively newly described component of elbow dysplasia and often occurs in association with FMCP and UAP. Management of this incongruence is becoming more widely accepted as part of the aetiopathogenesis and overall management strategy. 

Diagnosis:

The fact that this condition commonly occurs bilaterally and can affect multiple areas of the joint suggests that a thorough investigation of both elbow joints is appropriate when evaluating elbow dysplasia cases. CT scan of the elbows as well as arthroscopy constitutes the standard of care for diagnosing the various components of elbow dysplasia at Southpaws. Performing both of these tests is important to help minimise the risk of missing a lesion. It also allows a complete assessment of the elbow joint and the treatment to be tailored to the individual patient. 

Treatment:

Treatment options for elbow dysplasia are varied and continue to evolve. I subdivide these treatments broadly into medical and surgical options. Medical management is focused on treating the osteoathritis and includes:
  • Weight reduction
  • Exercise modification/physical therapy
  • Pentosan/cartrophen/zydax injections
  • EPA rich diet 
  • NSAID’s as needed 
  • More recently the use of biologics such as stem cells and platelet rich plasma have been investigated. We have been performing stem cell therapy at Southpaws for about 5 years. The results generally are very good with approximately 85% of animals having a positive response. About half of these cases have a dramatic improvement in their clinical signs. There is growing scientific data to support the use of these biologic products in the management of osteoarthritis. 
Surgical treatment options are further divided into general categories. The combination of procedures chosen for a specific patient varies depending on age, degree of incongruity and severity of cartilage loss and osteoarthritis. Surgery should not be considered a standalone intervention. Due to the high incidence of osteoarthritis progression, adjunctive medical management (above) should be considered for all surgical cases.  
  • Focal procedures - these have been around for a long time and include removal of the osteochondral fragment (OCD and FMCP) and some form of treatment to the underlying subchondral bone to help encourage the formation of fibrocartilage. With this type of treatment alone there is often progression of osteoarthritis. About 30% of dogs will have little to no improvement.  
  • Unloading procedures - these procedures aim to reduce the force transmission through the medial compartment of the joint. The intent is that there will be less cartilage destruction, slower progression of osteoarthritis and improvement of patient comfort and function. At Southpaws we have been performing the PAUL procedure for the last 12 months. We have generally been very happy with the results and have seen few complications. PAUL is often performed in conjunction with focal treatments and can be used in dogs of any age. 
  • Resurfacing procedures - the CUE system is a relatively new procedure which is a very exciting alternative to the traditional total elbow replacement systems. It is appropriate for dogs with severe medial compartment disease i.e. bone on bone contact between the medial humeral condyle and the medial coronoid process. 
CUE surgery is generally reserved for middle aged to older animals (>5 years). There is a relatively low risk of complications and results to date are generally very good. Unpublished data (in press) indicate that >80% of animals will return to full function. This procedure is now available at Southpaws and we are happy to accept cases for assessment.  

As always, if you would like any advice on managing patients with elbow dysplasia, about the techniques or procedures listed here or any other surgical questions. Please feel free to contact the clinic. 
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Moorabbin | Camberwell | Point Cook
Phone: (03) 9553 1775 Fax: (03) 8677 7630
Email: info@southpaws.com.au


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