Congress on Demand 2021: Surgery

Lumpectomies made interesting: Veterinary surgeons love lumpectomies but each extent of oncological surgery depends on the type and stage of the tumour. A pre-resection biopsy is often necessary to anticipate sufficient margins of resection and behaviour of the primary tumour. Staging the tumour will prevent treatment failures caused by early metastasis and will help in deciding the type of resection and use of adjuvant treatment modalities. Diagnosis of intercurrent diseases often will alter surgical treatment options and should be evaluated beforehand to assess the risk versus benefit of surgical intervention. The surgical field should be prepared carefully to allow changes in the extent of resection based on new information obtained during the operation. The necessary surgical margins depend on the tumour type, grade, and the anatomical location of the tumour. The most rational approach is to think of biologic rather than geometric margins and to combine this information with the expected growth behaviour of the given tumour type. Tumours with a high probability of local recurrence (e.g. mast cell tumours, feline mammary tumours) should have 2 to 3 cm margins removed three-dimensionally. Collagen/matrix-rich and poorly vascularised tissues are least vulnerable to tumour invasion and may be used for margin determination. All previously performed biopsy tracts should be removed in continuity with the primary tumour to prevent tumour seeding. With a proper resection the tumour is never visualized.

Skin reconstruction techniques: The reconstruction of wounds – either traumatic or those created following resection of tumours – provides an opportunity to bring skin edges into approximation. Dogs and cats have very adaptable skin, and a range of reconstructive procedures are described allowing sections of skin to be rotated, advanced and transposed to cover an adjacent defect. However, skin can be very unforgiving of inappropriate technique. As the complexity of a reconstructive surgery increases, the potential for disastrous outcome increases with either partial or complete failure of the skin flap. A successful outcome requires an understanding of blood supply, effective management of tension and a sound operative technique. Ideally, a wound should be closed without tension. Excessive tension may lead to vascular compromise and delayed healing. At worst, this may result in catastrophic dehiscence of the wound. Less serious complications include increased post-operative discomfort (which may lead to self-aggravation of the wound by the patient) and more unsightly scar formation. If excessive effort is required to achieve wound closure (e.g. brute strength, excessive use of stents, heavy gauge suture), it would be preferable to consider an alternative approach to wound reconstruction that recruits additional skin into the defect. A successful wound reconstruction will take account of skin tension. The surgeon should have an understanding of the methods used to ameliorate the effects of skin tension on wound healing. Many of these methods are straightforward, whilst others require some innovation and ingenuity. This lecture explores some of the many local flap and reconstructive options available in the dog and cat. Case examples are used to illustrate issues of importance and how to manage any complications should they develop.