Tolerance of Cutaneous or Mucosal Flaps Placed into a Radiation Therapy Field in Dogs

Reverse Pedicle U-Shaped Palatal Flap: An Innovative Technique for Repair of Severe Caudal Palatal Defects in Two Dogs

An acquired palatal defect in dogs is a pathologic condition in which there is communication between the oral cavity and nasal cavities, maxillary recesses, or orbits. Many different causes exist and must be considered. Two dogs were presented for severe palatal defects secondary to a foreign body trapped between maxillary dental arches. Numerous techniques have been previously described to repair palatal defects, and the most appropriate choice is based on the clinical features of the defect and information obtained from advanced diagnostic imaging. Acquired palatal defects are not predictable in shape, size, and location; therefore, although the literature contains many different surgical techniques, these are not always reliable. The aim of this article is to describe an innovative surgical approach to repair severe acquired caudal palatal defects in two different dogs.

Evaluating the relevance of surgical margins. Part one: The problems with current methodology

The goal of cancer surgery is to achieve a "clean" microscopic resection, with no residual tumour remaining in the wound. To achieve that goal, the surgeon typically incorporates a measured buffer of grossly normal tissue about the entire circumference of the tumour. Microscopic analysis of the resection boundaries is then performed to determine if all traces of the tumour have been completely removed. This analysis is thought to provide a surrogate indication as to the likelihood for that tumour to recur after surgery. However, it is recognised that tumour recurrence may not occur even when microscopic evidence of tumour has been identified at the resection margins, and recurrence can also occur when conventional histology has considered the tumour to have been completely removed. The explanations for this dichotomy are numerous and include technical and practical limitations of the processing methodology, and also several surgeon-related and tumour-related reasons. Ultimately, the inability to confidently determine when a tumour has been removed sufficiently to prevent recurrence can impact on the ability to provide owners with confident treatment advice. In this article, the authors describe the challenges with defining the true extent of the tumour margin from the perspective of the surgeon, the pathologist and the tumour. The authors also provide an analysis of why our current efforts to ensure that all traces of the local tumour have been successfully removed may provide an imperfect assessment of the risk of recurrence.

Sternohyoideus-sternothyroideus muscle flap to reconstruct oronasal fistulas due to maxillary cancer in four dogs

OBJECTIVE

To describe the repair of oronasal fistulas in dogs treated for maxillary cancer, with a novel sternohyoideus-sternothyroideus muscle flap, and to report the outcome.

ANIMALS

Client-owned dogs (n = 4) with oronasal fistulas related to cancer.

STUDY DESIGN

Short case series.

METHODS

Maxillary defects were caused by tissue destruction by the tumor and tumor response to radiation therapy in two cases and a complication of caudal maxillectomy in two cases, one of which had neoadjuvant radiation therapy. All tumors were >4 cm at the level of the maxilla. Flaps were harvested by transecting the ipsilateral sternothyroideus and sternohyoideus muscles from their origin at the manubrium and costal cartilage. The muscles were rotated around the base of the cranial thyroid artery and tunneled subcutaneously in the neck and through an incision in the caudodorsal aspect of the oral cavity. The muscle flap was sutured to the edges of the oronasal fistula.

RESULTS

The flap reached as far rostral as the level of the first premolar without tension. All dogs had clinical signs that improved postoperatively. All dogs had partial dehiscence of the flap.

CONCLUSION

This flap was associated with a high rate of complications; however, all flaps were used in challenging cases. Clinical signs related to oronasal fistula were improved in all dogs in this case series.

Marginal excision of cutaneous mast cell tumors in dogs was not associated with a higher rate of complications or prolonged wound healing than marginal excision of soft tissue sarcomas

OBJECTIVE

To compare wound healing following planned marginal excision of cutaneous mast cell tumors (MCTs) with that of soft tissue sarcomas (STSs) and to identify risk factors for wound healing complications and delay in healing.

ANIMALS

126 dogs that underwent intentional marginal excision of cutaneous MCTs (n = 77) or subcutaneous STSs (49).

PROCEDURES

Medical records of included dogs were reviewed and signalment, tumor size, tumor location, skin closure type, time to healing, reported complications, histopathological grade, and surgical margins were recorded. These variables and outcomes (complication rate and time to complete healing) were compared between dogs in the MCT and STS groups. Potential risk factors for complications and delayed healing were analyzed.

RESULTS

No significant difference between the groups was found in any of the variables. Wound healing complication rates were 29% (22/77) for the MCT group and 31% (15/49) for the STS group. The mean ± SD time to complete healing was 16.5 ± 7.5 days for the MCT group and 17.7 ± 9.3 days for the STS group. These outcomes did not differ significantly between groups. For both groups, the use of subdermal plexus flap reconstruction was associated with the development of complications and increased time to complete healing.

CLINICAL RELEVANCE

Marginal excision of cutaneous MCTs was not associated with a higher rate of complication or prolonged wound healing, compared with marginal excision of STSs. The use of flap reconstruction in skin closure may delay healing and planned adjuvant therapy. Owners should be counseled regarding these risks and where appropriate and feasible, surgery without reconstruction should be considered.

Analysis of risk factors associated with complications following mandibulectomy and maxillectomy in dogs

OBJECTIVE

To provide information about complication rates and the risk factors for complications with mandibulectomy and maxillectomy procedures in dogs.

ANIMALS

459 client-owned dogs that underwent a mandibulectomy or maxillectomy between January 1, 2007, and January 1, 2018.

PROCEDURES

Inclusion criteria included a complete medical record that contained an anesthesia record, surgical report, available histopathology results, and results of CBC and serum biochemical analysis before surgery. A minimum follow-up of 90 days after surgery was required.

RESULTS

271 complications occurred in 171 of 459 (37.3%) dogs. Eighteen complications were not given a severity description. Of the remaining 253 complications, most were considered minor (157/253 [62.1%]). Multivariable logistic regression analysis revealed that only increased surgical time had a significant (OR, 1.36; 95% CI, 1.12 to 1.54) association with the occurrence of ≥ 1 complication. For each additional hour of surgery, the odds of complications increased by 36%. Preoperative radiation therapy or chemotherapy increased the odds of incisional dehiscence or oral fistula formation (OR, 3.0; 95% CI, 1.3 to 7.2). Additionally, undergoing maxillectomy, compared with mandibulectomy, increased the odds of incisional dehiscence or oral fistula formation (OR, 1.8; 95% CI, 1.1 to 3.1). Two hundred forty-four of 271 (90.0%) complications occurred in the perioperative period (0 to 3 months after surgery).

CONCLUSIONS AND CLINICAL RELEVANCE

Compared with mandibulectomy, performing maxillectomy increased the risk for incisional dehiscence or oral fistula formation. Mandibulectomy and maxillectomy had a moderate risk for a complication.

Neoadjuvant chemotherapy and radiation therapy in veterinary cancer treatment: a review

Multi-modality treatment strategies are more becoming commonplace in veterinary oncology practice yet the evidence base is far inferior to what has been generated in people. Surgery is unquestionably the cornerstone of most solid tumour treatment plans but certain scenarios dictate combining surgery with systemic chemotherapy and radiation therapy as an adjunct. By using these in the neoadjuvant setting, one can leverage certain effects of the treatment to improve local disease control, improve overall survival, gain insight into drug efficacy, reduce surgical morbidity and reduce long-term complications. An unintended consequence of combining therapies is an increased flow of information between members of the care team upfront that in almost all cases leads to improved patient outcomes albeit a difficult metric to quantify. This review sets out to explore some of the principles of neoadjuvant therapies and discuss potential opportunities to expand the evidence base in veterinary medicine.

Management of Radiation Side Effects to the Skin

Radiation therapy (RT) is an essential component for management of many cancers. Veterinary health care professionals must counsel owners about the potential side effects of RT, the anticipated management plan, and associated costs. For most veterinary patients treated with RT, acute radiation side effects are mild; however, careful radiation treatment planning and appropriate management of acute side effects are essential to try to prevent chronic sequelae and the need for ongoing wound care. This article reviews acute and late side effects to the skin and their management.

Axial Pattern Flaps

Axial pattern flaps are based on a direct cutaneous artery and vein supplying a segment of skin. They provide a large, robust option for large wound closure. Many different axial pattern flaps have been described to provide options for closure of wounds located from the nose to the tail. All axial pattern flaps require good surgical technique and careful attention to detail while developing of the flap.

Wound Care

Wound care requires an understanding of normal wound healing, causes of delays of wound healing, and the management of wounds. Every wound must be treated as an individual with regard to cause, chronicity, location, and level of microbial contamination, as well as patient factors that affect wound healing. Knowledge of wound care products available and when negative pressure wound therapy and drain placement is appropriate can improve outcomes with wound healing. Inappropriate product use can cause delays in healing. As a wound healing progresses, management of a wound and the bandage material used must evolve.

Role of surgery in multimodal cancer therapy for small animals

Surgery is a critical component in the treatment of most solid tumors in small animals. Surgery is increasingly combined with adjuvant therapies such as chemotherapy and radiation so surgeons who are treating cancer must have a good understanding of surgical oncology principles, cancer biology, and the roles and potential interactions of surgery, radiation, and chemotherapy. The sequencing plan for these modalities should be determined before treatment is initiated. The surgical oncologist must have a working knowledge of chemotherapy agents and radiation and the effect of these treatments on the ability of tissues to heal and the outcome for the patient.

Oronasal fistula repair utilizing a temporalis muscle flap in a dog with severe trismus

A 9 yr old spayed female cocker spaniel presented for evaluation of an invasive maxillary squamous cell carcinoma. Curative intent surgery and radiation therapy allowed for local control of the neoplasm; however, the development of a persistent oronasal fistula prevented a complete recovery. A temporalis myofascial rotation flap allowed for successful resolution of the maxillary defect. Implementation of the flap was relatively simple and was associated with few complications.