Metastatic extramedullary plasmacytoma of the colon and rectum in a dog.

Stage-3 extramedullary plasmacytoma of the large intestine was diagnosed in an 8-year-old Labrador Retriever. Three primary tumors were located in the colon and rectum, with metastasis to local lymph nodes and the spleen. The disease was associated with a monoclonal serum protein spike identified as IgG. Treatment consisted of surgical excision followed by chemotherapy, using melphalan and prednisone. The dog remained free from clinical signs of disease and adverse effects of the chemotherapy at 9 months. Findings in this dog indicated that extramedullary plasmacytoma may be an aggressive disease, associated with spread to distant sites and monoclonal gammopathy.

Tympanic bulla osteotomy for treatment of middle-ear disease in cats: 19 cases (1984-1991).

Twenty-two tympanic bulla osteotomies were performed in 19 cats for the treatment of bacterial otitis media (n = 11), inflammatory polyps (n = 7), or middle-ear neoplasia (n = 4). Inflammatory polyps mostly affected young adult cats (mean age, 1.5 years), whereas otitis media affected middle-aged cats (mean age, 5.5 years) and neoplasia affected older cats (mean age, 10.25 years). Although not specific for the underlying disease process, fluid density within the tympanic bulla or thickening of the bulla was observed radiographically in 100% of cats with middle-ear disease. In cats for which results were available, bacterial culturing revealed pathogens in 6 cats diagnosed with otitis media and in 7 cats with benign or malignant tumors within the bulla. The ventral approach to the bulla was the most common surgical procedure (18 osteotomies), followed by the lateral approach combined with ablation of the vertical and horizontal parts of the external acoustic meatus (4 osteotomies). Immediate postoperative complications were common but short-term, and included Horner's syndrome (11 cats), facial nerve paralysis (5 cats), and otitis interna (2 cats). Bulla osteotomy resulted in resolution of clinical signs without recurrence in cats with middle-ear polyps. Drainage of the infected tympanic cavity aided in resolution of the clinical signs of bacterial otitis media, but the long-term clinical course was characterized by persistent neurologic deficits (5 cats) and recurrence of disease (2 cats). Neoplastic infiltration of the tympanic bulla was associated with a poor prognosis, and although surgery helped to establish a diagnosis, it did not alter the clinical course of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the proximal portion of the femur as an autogenous cancellous bone donor site in dogs.

The proximal portion of the femur was evaluated as a source of autogenous cancellous bone in dogs. Bilateral oval cortical defects were created in the lateral subtrochanteric area of the femur in 16 dogs. Cancellous bone was removed and the weight recorded. Cancellous bone was similarly harvested from the proximal portion of the humerus in 7 of these dogs. Subtrochanteric femoral defects in 11 dogs were randomly assigned to receive cancellous bone graft obtained from the femur (n = 4) or the humerus (n = 7). Subtrochanteric defects in 5 dogs were not grafted. Radiographic assessment of subtrochanteric defects was performed at 4-week intervals, and histologic assessment at 4, 8, 16, and 24 weeks after surgery. Nongrafted donor sites healed by ingrowth of trabecular bone during the first 12 weeks after surgery. By week 24, the lateral cortical wall had reformed, but remodeling was incomplete. Donor sites grafted with cancellous bone healed similarly, but with more rapid healing and more complete remodeling evident by week 24. Although the mean weight of cancellous bone harvested from the proximal portion of the femur (0.82 +/- 0.22 g) was significantly (P less than 0.05) less than that harvested from the proximal portion of the humerus (1.38 +/- 0.29 g), there was no qualitative histologic or radiographic difference in bony healing of grafted defects. We determined that the proximal portion of the femur can be safely used to provide moderate amounts of cancellous bone, and that a second bone graft can be collected from the same subtrochanteric donor site after 12 weeks.

Clinical evaluation of axial pattern skin flaps in dogs and cats: 19 cases (1981-1990).

Nineteen axial pattern skin flaps were used in 16 dogs and cats to provide skin for repair of extensive cutaneous defects. Retrospective evaluation of medical records was used to determine percentage flap survival, postoperative complications, and long-term outcome of axial pattern skin flaps. The most common indication for use of axial pattern flaps was to augment wound closure following tumor resection (n = 7). Other indications included trauma (n = 5), chronic nonhealing wounds (n = 4), urine-induced cellulitis (n = 1), idiopathic dermal necrosis (n = 1), and chronic lymphoplasmocytic dermatitis (n = 1). Mean flap survival (+/- SD) was 96% (+/- 8). Postoperative complications included wound drainage (n = 15), partial dehiscence of the sutured flap (n = 7), distal flap necrosis (n = 6), infection (n = 3), edema (n = 3), and seroma formation (n = 2). After a median follow-up time of 5 months, evaluation of animals indicated that surgery provided successful wound reconstruction with good cosmetic results. Reconstruction of large cutaneous defects is facilitated by axial pattern flap application regardless of cause of wound. Postoperative complications are common but amenable to standard wound management techniques such as drain placement and surgical debridement of devitalized distal flap skin.

Evaluation of biocompatible osteoconductive polymer as an orthopedic implant in dogs.

The biocompatibility and osteoconductive properties of biocompatible osteoconductive polymer (BOP), a synthetic implant, were evaluated. Bilateral oval cortical defects (1 x 2 cm) were made in the lateral subtrochanteric area of the proximal portion of the femur in 16 dogs that later were treated with BOP fiber (n = 16) or autogenous cancellous bone (n = 11), or were not treated (n = 5). The BOP block was attached extraperiosteally to the proximal portion of the humerus in 6 dogs. Radiographic assessment of surgery sites was performed at 4-week intervals, and histologic evaluation was performed at 4, 8, 16, and 24 weeks after surgery. Radiographic signs of bone healing were not observed in defects treated with BOP fiber. Defects treated with cancellous bone or not treated had radiographic signs of progressive bone ingrowth. Radiographic evidence of periosteal new bone formation near control and BOP-treated defects was observed 4 weeks after surgery; increased periosteal reaction was associated with BOP fiber. This new bone had resorbed by week 24, except bone adjacent to BOP fiber, where continued periosteal reaction was apparent. Histologic evidence of bone formation was observed extending to, but not incorporating, BOP fibers. The BOP fibers became surrounded by a fibrous capsule, and fibrovascular connective tissue infiltrated between and into BOP fibers, but minimal bone formation incorporated the BOP material during the follow-up period. During that time, active periosteal new bone formation was evident adjacent to the BOP fibers. Defects treated with cancellous bone or not treated healed by ingrowth of cancellous bone during the first 12 weeks after surgery and by reformation of the lateral cortical wall by week 24. The BOP blocks became surrounded by a fibrous capsule, but connective tissue or bone ingrowth into BOP blocks was not observed. Results indicate that BOP is not osteoconductive within a 6-month time frame when used in subtrochanteric femoral defects or when placed extraperiosteally on the proximal portion of the humerus of clinically normal dogs.

Direct cutaneous arterial supply to the tail in dogs.

Cutaneous arterial blood supply to the tail was evaluated in 12 dogs. Subtraction radiography of internal iliac artery and distal aorta angiography in 3 of these dogs was used to determine arterial blood supply to the tail from the median sacral and lateral caudal arteries. Dissection of the tail in 8 canine cadavers revealed bilateral subcutaneous location of lateral caudal arteries following tail amputation. An axial pattern flap based on the lateral caudal arteries contributed to the reconstruction of a large caudodorsal cutaneous defect in a dog. An axial pattern flap based on the lateral caudal arteries following tail amputation may be indicated to aid reconstruction of large caudodorsal cutaneous defects of the trunk in dogs.

Healing characteristics of free and pedicle fat grafts after dorsal laminectomy and durotomy in dogs.

Dorsal laminectomy and durotomy were performed at thoracic vertebrae 12 and 13 (T12-T13) and lumbar vertebrae 1 and 2 (L1-L2) in 12 normal dogs. A free fat graft harvested from subcutaneous tissue adjacent to the incision was placed over the T12-T13 laminectomy site. A 75 X 25 X 5 mm pedicle fat graft harvested from a similar location was placed over the L1-L2 laminectomy site. Three dogs each were euthanatized at weeks 2, 4, 8, and 16. With both types of fat grafts, an initial inflammatory stage reduced the size of the graft approximately 50%. Axonal degeneration and demyelination of the spinal cord resolved by week 16. At week 16, the durotomy sites had healed, but the dura mater was adhered to the spinal cord. No difference between the grafts could be demonstrated by antemortem myelography and cerebrospinal fluid analysis. There was no demonstrable advantage to the use of pedicle fat grafts.