Fascial plane mapping for superficial tumor resection in dogs. Part III: Hindlimb and pelvis.

OBJECTIVES: To categorize the fascial planes and the intersections of these fascial planes in the hindlimb of the dog to facilitate preoperative planning for superficial cancers. STUDY DESIGN: Qualitative anatomical study. SAMPLE POPULATION: Four male and five female mixed breed dogs, weighing ~15-35 kg. METHODS: Skin and subcutaneous fat were removed, and fascial planes were explored to determine borders and quality. Fascia was categorized as type I (discrete sheets), type II (adhered to thin muscles), type III (adhered to thick muscles), or type IV (associated with periosteum). Digital modification of specimen photographs was performed to map tissues. RESULTS: Differences in dogs were noted due to either size or sex but were sufficiently minor to allow mapping. Fasciae of the hindlimb were predominantly type II or III, with type I fascia primarily at the lateral gluteal region, fascia lata, and lateral crus. Type IV fascia was seen at the iliac wing, ischium, patella, tibial tuberosity, medial tibia, distal crus, and pes. Fascia for surgical use was thin or absent at the ischiorectal fossa, femoral triangle, extensor mechanism, medial and distal crus, and pes. Intersections and tissues at the ventral perineum may also pose challenges for maintenance of a deep margin. CONCLUSION: Fascial types and integrity of the hindlimb varied with location, with the perineum, cranial stifle, and distal limb presenting the greatest challenges. CLINICAL SIGNIFICANCE: These images may be used to guide both therapeutic decision-making and intraoperative excision of superficial tumors of the hindlimb and pelvis.

Fascial plane mapping for superficial tumor resection in dogs. Part II: Forelimb.

OBJECTIVE: To detail the qualitative fascial categories and fascial intersections of the forelimb of the dog to facilitate preoperative planning for superficial cancers. STUDY DESIGN: Qualitative anatomical study. SAMPLE POPULATION: Three male and four female mixed breed canine cadavers weighing approximately 20-35 kg. METHODS: The skin and subcutaneous fat were excised. Fascial planes were incised and elevated to allow exploration of their quality and borders. Fascia was categorized as type I (discrete sheets), type II (tightly adhered to thin muscles), type III (tightly adhered to thick muscles), or type IV (associated with periosteum). Photographs of specimens were digitally modified with overlays to map tissue types. RESULTS: Differences between the cadavers used were largely based on muscle mass and sex, with minimal other subjective differences affecting fascial mapping. The fasciae of the forelimb were largely type II or type III, with type I fascia at the antebrachium and type IV fascia at the olecranon, scapular spine, and accessory carpal bone. Fascial integrity was often questionable or lacking distal to the distal quarter of the antebrachium. CONCLUSION: The fascial types and integrity of the forelimb varied with anatomic location with thin or absent fascia for surgical use at the elbow, carpus, and manus. CLINICAL SIGNIFICANCE: This study provides information for preoperative planning and excision of superficial tumors of the forelimb. Knowledge of the potential limitations of fascia to provide a deep margin may influence selection of treatment modalities.

Focused ultrasound tumour ablation in small animal oncology.

The cancer incidence rates for humans and animals remain high, and efforts to improve cancer treatment are crucial. Cancer treatment for solid tumours includes both treatment of the primary tumour and of metastasis. Surgery is commonly employed to resect primary and metastatic tumours, but is invasive, and is not always the optimal treatment modality. Prevention and treatment of metastatic disease often utilizes a multimodal approach, but metastasis remains a major cause of death for both human and veterinary cancer patients. Focused ultrasound (FUS) tumour ablation techniques represent a novel non-invasive approach to treating cancer. FUS ablation is precise, thus sparing adjacent critical structures while ablating the tumour. FUS ablation can occur in a thermal or non-thermal fashion. Thermal FUS ablation, also known as high intensity focused ultrasound (HIFU) ablation, destroys tumour cells via heat, whereas non-thermal FUS, known as histotripsy, ablates tumour cells via mechanical disintegration of tissue. Not only can HIFU and histotripsy ablate tumours, they also demonstrate potential to upregulate the host immune system towards an anti-tumour response. The aim of this report is provide a description of HIFU and histotripsy tumour ablation, with a focus on the basic principles of their ablation mechanisms and their clinical applicability in the field of veterinary oncology.

Outcome and postoperative complications in 73 dogs with thyroid carcinoma with gross vascular invasion managed with thyroidectomy.

Excellent outcomes have been reported following thyroidectomy for thyroid carcinoma in dogs, but outcomes for thyroid carcinomas with gross vascular invasion are poorly described. This study describes the clinical outcomes and complications in dogs with thyroid carcinomas with gross vascular invasion undergoing thyroidectomy. Medical records of dogs that underwent thyroidectomy between January 1st 2010 and December 31st 2019 were reviewed at 10 hospitals. Signalment, diagnostic data, primary and adjuvant treatments performed, and outcome were abstracted. Survival was calculated using Kaplan-Meier analysis. Multiple logistic regression was used to identify variables associated with disease-specific survival. Seventy-three dogs were included, of which 58 underwent unilateral thyroidectomy and 15 underwent bilateral thyroidectomy. Complications were reported in five dogs (three major, two minor; 6.8%) intraoperatively and 12 dogs (two major leading to death, 10 minor; 16.4%) postoperatively. Seven (9.6%) dogs developed locoregional recurrence at a median of 238 days postoperatively (range: 15-730 days). Distant metastasis was suspected or confirmed in nine dogs (12.3%) at a median of 375 days postoperatively (range: 50-890 days). Twenty-seven dogs (37%) received adjuvant therapy (chemotherapy: n = 21; radiotherapy: n = 6). Thirty-nine dogs were euthanized or died, with 20 deaths related to disease (n = 10) or of unknown cause (n = 10), 19 due to unrelated causes, and nine lost to follow-up. Median overall and disease-specific survival were 621 days and not reached respectively. One-year disease-specific survival rate was 82.5%. No variables were associated with disease-specific survival in our dataset. Surgery may be considered for loco-regional therapy in dogs with thyroid carcinoma with gross vascular invasion.

Clinical outcomes in dogs with localized splenic histiocytic sarcoma treated with splenectomy with or without adjuvant chemotherapy.

BACKGROUND: Localized splenic histiocytic sarcoma (HS) in dogs is a poorly understood disease, and could have longer survival times than disseminated or hemophagocytic HS. Understanding the clinical behavior of localized splenic HS can refine treatment recommendations. OBJECTIVE: To describe the clinical characteristics and outcomes of dogs with localized splenic HS. ANIMALS: Fourteen client-owned dogs with histologically confirmed splenic HS that received splenectomy. METHODS: Multi-institutional retrospective case series-medical records of dogs with splenic HS were reviewed. Dog signalment, clinicopathologic data, primary and adjuvant treatments, and outcomes were obtained. Survival data were calculated using Kaplan-Meier analysis. Dog variables such as age, weight, platelet counts were reported using descriptive statistics. The Cox proportional hazards regression method was used to determine whether potential risk factors (weight, age, albumin level, hematocrit, and platelet count) were associated with PFI. RESULTS: Median survival time for the dogs in this study was 427 days. Twelve dogs received adjuvant lomustine-based chemotherapy. Five dogs (35.7%) were suspected or confirmed to have developed metastatic disease. Eleven dogs died of disease, 1 dog died of unrelated cause, and 2 dogs were alive at final follow-up. CONCLUSIONS AND CLINICAL SIGNIFICANCE: Histiocytic sarcoma in dogs can manifest as a localized form in the spleen. Dogs with localized splenic HS treated with surgery ± chemotherapy can experience survival times over a year.