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Biomedical subjects

J D Fowler

Publications and source records attributed to J D Fowler.

35 records · Page 2Linked to original sources

Prognostic factors for tumor remission and survival in dogs after surgery for primary lung tumor: 76 cases (1975-1985).

The association of various prognostic factors with remission and survival after the excision of lung tumors was evaluated in 76 dogs. Overall, the median survival time of treated dogs was 120 days; 72% had tumor that underwent remission (median duration of remission, 120 days). Dogs with tumors that underwent remission had significantly (P = 0.001) increased survival time (median, 330 days vs 28 days for dogs with tumors that did not undergo remission). The finding of normal-sized lymph nodes at the time of therapeutic thoracotomy was significantly (P = 0.001) correlated with increased remission probability (85.4% remission rate vs 43.6% in dogs with large lymph nodes). Use of various diagnostic methods to find normal regional lymph nodes before surgery indicated that such finding was significantly (P less than or equal to 0.01) correlated with increased remission duration (median remission duration, 365 days, vs 60 days for tumors in dogs with large lymph nodes), and the finding of normal lymph nodes at the time of surgery was significantly (P less than or equal to 0.01) correlated with increased survival time (median, 345 days, vs 60 days for dogs with large lymph nodes).

Adenocarcinoma↗

Unsuccessful surgical repair of a short soft palate in a dog.

An 8-week-old male Miniature Schnauzer had nasal discharge of milk, food, and water since birth, especially during eating. Examination of the oral cavity revealed a short soft palate. Numerous unsuccessful surgical procedures were performed to construct a shelf of tissue to prevent oronasal reflux. The dog was euthanatized.

Animals↗

Effect of ischemia and reperfusion on neutrophil accumulation in equine microvascular tissue flaps.

OBJECTIVE: To investigate neutrophil accumulation after ischemia and reperfusion (IR) in microvascular tissue flaps in horses. STUDY DESIGN: Randomized controlled experiment. SAMPLE POPULATION: A total of 8 horses between 1 and 10 years of age, 4 of each sex. METHODS: Control and experimental myocutaneous island flaps based on the superficial branch of the deep circumflex iliac vessels were dissected on each horse. Atraumatic vascular clamps were applied to the pedicle of the experimental flap for 90 minutes and then removed to allow reperfusion. Based on the assumption that rapid infiltration of neutrophils into affected tissues is a hallmark of IR injury, radiolabeled autogenous leukocytes were used to indirectly quantify neutrophil accumulation in flap tissues. Labeled leukocytes were administered through a jugular catheter 30 minutes before flap reperfusion. Biopsies were collected from each flap over a 6 hour postischemia time period; in group 1 (n = 4) from 0 to 6 hours postischemia, and in group 2 (n = 4) from 24 to 30 hours postischemia. Biopsies were examined scintigraphically and histologically for evidence of neutrophil infiltration. RESULTS: All control flaps survived and 6 of 8 experimental flaps survived. There was no significant evidence of acute neutrophil infiltration into flap tissues after reperfusion in either group. CONCLUSIONS: The results of this study suggest that equine myocutaneous flap tissues can survive a 90-minute ischemic period and reperfusion. No significant evidence of the occurrence of IR injury in flap tissues was found. CLINICAL RELEVANCE: The reasons for the previously reported failures of equine free tissue transfer remain uncertain, but they do not appear to be caused by neutrophil mediated injury associated with ischemia and reperfusion.

Animals↗

Conservative versus surgical management of gastrointestinal linear foreign bodies in the cat.

Twenty-four cases of gastrointestinal linear foreign bodies (LFB) in cats were reviewed. Nine cats were successfully managed conservatively, with passage of the LFB occurring 1 to 3 days after presentation. Ten cats that were initially managed conservatively were subsequently treated surgically. The decision to operate was based on worsening of clinical signs and failure to pass the LFB. Five cats were initially treated surgically. The cats that were managed successfully via conservative treatment had a shorter duration of clinical signs before presentation, decreased incidence of abdominal pain and palpable intestinal plication, and less severe hematologic abnormalities. Radiographic signs were of little benefit in deciding whether to treat the cats conservatively or surgically. None of the cats died.

Animals↗

Proximal urethral reconstruction using a distally based ventral bladder tube flap. An experimental study.

Reconstruction of the proximal urethra using a distally based tube flap mobilized from the ventral bladder wall was performed on 12 clinically normal dogs after total prostatectomy and resection of 2 cm of membranous urethra. One dog was euthanized at 6 hours and one at 36 hours after surgery because of surgical complications. Five dogs were euthanized at 10 days, two dogs at 6 weeks and three dogs at 12 weeks. Advancement of the tube flap allowed for tension-free anastomosis to the membranous urethra. Vascular integrity was maintained in all flaps. Intermittent to continuous postoperative urinary incontinence occurred in 7 of 10 dogs. The incontinence was transient in all 6 and 12 week dogs except one in which a persistent stress incontinence developed. Mild to severe dysuria was noted in 8 of 10 dogs, but was also transient in all of the 6 and 12 week dogs, with the exception of one dog. Postoperative urethral closure pressure profilometry revealed decreased tone in the membranous urethra in all 6 and 12 week dogs. It was concluded that proximal urethral reconstruction, using a ventral bladder tube flap, is a viable technique that may permit functional urodynamic recovery in dogs with significant proximal urethral loss.

Anastomosis, Surgical↗

Transfer of free vascular cutaneous flaps by microvascular anastomosis. Results in six dogs.

Skin defects on the distal extremities of six dogs were reconstructed with free vascular cutaneous transfers by microvascular anastomosis. The donor flaps were based on the superficial cervical artery and vein. In five of the dogs, bone was exposed and skin was lost from half of the circumference of the limb. Two had infected fractures with sequestra and three had acute shearing injuries. The sixth dog had sensory denervation of the left antebrachium and a carpal acral lick granuloma. Before surgery, the patency of potential recipient vessels was confirmed with arteriography in five dogs and an ultrasonic doppler in one dog. Microvascular technique was used to reestablish circulation to the flaps after they were transferred to the recipient site. Total ischemic time of the flaps averaged 100 minutes. All flaps survived. Successful reconstruction of the cutaneous defects was achieved in these six cases.

Anastomosis, Surgical↗

A developmental model for free vascularized bone transfers in the dog.

An autogenous free vascular bone transfer using a segment of ulna along with its periosteum and vascular pedicle was developed. The vascular pedicle, based on the common interosseous artery and vein, emerged where muscular branches from the cranial interosseous artery enter the extensor carpi ulnaris and lateral digital extensor muscles. Four autogenous heterotopic (ulna to tibia) vascular transfers by microvascular anastomosis and two avascular transfers were performed to compare the osteogenic potential and viability of free revascularized grafts with avascular bone grafts. Successful microvascular anastomosis was demonstrated in three of the four vascular transfers by early bone scanning using technetium-labeled polyphosphate. Radiographically, there was more periosteal new bone and callus formation in the successfully revascularized bone transfers than in the failed vascular transfer and the avascular controls. Histologically, viable bone with an intact medullary and periosteal vascular supply was recognized in the grafts successfully revascularized by microvascular anastomosis.

Animals↗

Microneurovascular free digital pad transfer in the dog.

By cadaver dissections, the fifth digit of the canine hind limb was determined to have a consistent neurovascular anatomy, and therefore be a suitable donor for an axial pattern digital pad flap. The defined digital pad flap was transferred to the region of an excised metacarpal pad by microneurovascular anastomoses in five operations on four dogs. One flap failure was considered to result from failure of the venous anastomosis. In all four successful transfers, cutaneous sensation was reestablished on average in 78 days. There was histologic evidence of nerve regeneration across the anastomosis in one dog at week 24. The transferred pads of three dogs monitored for 15 months underwent hypertrophic changes. There were no complications in two active dogs. In one dog, superficial ulceration of a region of the flap adjacent to the pad required surgical revision. This dog continued to show mild lameness after daily runs of 3 to 4 km.

Anastomosis, Surgical↗

The anatomic basis for a trapezius muscle flap in dogs.

The anatomy of the cervical part of the trapezius muscle and its dominant vascular supply, the prescapular branch of the superficial cervical artery, was studied by dissection and selective angiography of 16 canine cadavers. The prescapular branch of the superficial cervical artery supplies blood to the skin of the caudal half of the neck and the cervical part of the trapezius muscle and is a minor contributor to other muscles of the neck. In these dogs, the mean length of the vascular pedicles was 4.4 cm and the mean diameter was 1.0 mm. With this information, it is possible to design a broad musculocutaneous flap suitable for reconstructive microsurgery in dogs. The potential for successful incorporation of the scapular spine in such a flap remains uncertain.

Angiography↗

Free microvascular transplantation of the trapezius musculocutaneous flap in dogs.

A musculocutaneous flap based on the prescapular branch of the superficial cervical artery and including the cervical part of the trapezius muscle and overlying skin was transplanted over a defect created on the medial side of the contralateral tibia in four dogs by using microvascular technique. The donor and recipient sites in three dogs were examined clinically for 21 days, after which they were examined angiographically and histologically. All dogs were free of lameness by hour 48. Seromas formed at the donor site between days 7 and 15. One vascular pedicle was traumatized at hour 40, and the dog was euthanatized. Three flaps survived with minimal necrosis. Edema of the flaps was severe from days 5 to 11. Angiograms showed complete perfusion of the flaps, and survival was confirmed histologically. Esthetic appearance and function were good in one dog at month 7.

Anastomosis, Surgical↗

The trapezius osteomusculocutaneous flap in dogs.

A pedicled osteomusculocutaneous flap, composed of the cervical part of the trapezius muscle with its overlying skin and the central spine and body of the scapula, was elevated on the prescapular branch of the superficial cervical vascular pedicle in four dogs. The flap was replaced in an orthotopic location. Bone viability was evaluated using histology, fluorescence bone labeling, and angiography. Bone from the scapular spines had a high percentage of viable osteocytes, positive fluorescence, and vessels were outlined in the angiographic study. Bone from the body of the scapula was not viable based on similar criteria.

Animals↗

Development of a free latissimus dorsi muscle flap in cats.

Anatomic and experimental evaluation of the feline latissimus dorsi muscle was performed to assess its potential use as a free muscle flap. In the anatomic study, nonselective angiography of the subscapular artery was performed in nine heparinized feline cadavers. The muscle dimensions and vascular anatomy of the dissected latissimus dorsi muscle were recorded. In the experimental study four cats underwent heterotopic transplantation of a partial latissimus dorsi flap, and three cats underwent orthotopic transplantation of a complete latissimus dorsi flap. The mean length and width of the latissimus dorsi muscle was 19.0 and 5.4 cm, respectively. The dominant vascular pedicle was the thoracodorsal artery and vein. The average length and diameter of the thoracodorsal artery was 2.7 cm and 0.6 mm, respectively. Minor vascular pedicles were provided by branches of the intercostal arteries. Numerous choke anastomoses existed between the two pedicle systems. Viability of muscle flaps based on subjective evaluation, angiography, and histopathology, was 66% and 100% in the heterotopic and orthotopic studies, respectively. Flap failure seemed to be caused by both arterial and venous thrombosis. The latissimus dorsi muscle flap met criteria required for application in microvascular reconstruction. The vascular pattern was appropriate and consistent. Donor site morbidity was low, whereas surgical accessibility was high. The muscle satisfied the physical criteria of a free flap. Long-term anastomotic patency and flap viability was shown.

Animals↗

Deep hypothermic low flow cardiopulmonary bypass in small dogs.

OBJECTIVE: To evaluate the feasibility of and morbidity and mortality associated with cardiopulmonary bypass (CPB) using deep hypothermia and low flow perfusion in adult dogs weighing less than 10 kg. STUDY DESIGN: Prospective, descriptive study. ANIMALS: Two groups of three dogs underwent CPB. Group 1 dogs underwent deep hypothermia (15 to 18 degrees C), 45 minutes of low perfusion flow (20 mL/kg/min) and 1 hour of aortic cross clamp time. In group 2, ultrafiltration of perfusate before discontinuation of bypass was added to the standard treatment. Complete blood counts, serum biochemistry, urine output, ejection fraction, and cardiac output were monitored before and for 7 days after surgery. RESULTS: All dogs were successfully weaned from bypass. Four of six dogs survived, three without major complications. One dog developed and recovered from septic pleuritis. Two dogs died or were euthanatized after surgery because of respiratory or gastrointestinal complications. Minor complications included anemia, hypoproteinemia, and electrolyte disturbances. Transfusion requirements and edema formation were reduced by ultrafiltration. CONCLUSIONS: The observations in this study support the feasibility of low flow hypothermic CPB. Meticulous tissue handling, precise equipment, ultrafiltration, and aggressive postoperative potassium supplementation are recommended for smaller patients. CLINICAL RELEVANCE: Increased sensitivity to adverse sequelae of CPB may be associated with small patient size. Further evaluation is necessary before routine clinical application of low flow hypothermic CPB in this patient population.

Animals↗

Microvascular free tissue transfer: results in 57 consecutive cases.

OBJECTIVE: To evaluate the outcomes and complications in a consecutive series of animals undergoing microvascular reconstructive procedures at two veterinary institutions. STUDY DESIGN: Retrospective study. ANIMALS OR SAMPLE POPULATION: A total of 44 client-owned dogs and one red-necked wallaby. METHODS: The medical records of all animals undergoing reconstructive microsurgical procedures at the Western College of Veterinary Medicine and Michigan State University were reviewed. Microvascular flap survival and related complications were described. Statistical analysis was performed to determine the significance of relationships between operative factors and outcome. RESULTS: A total of 57 microvascular procedures were performed on 55 animals. Reconstruction was required after trauma in 42 animals, after ablative cancer surgery in 11 animals and for correction of congenital tissue aplasia in I animal. Donor tissues included the superficial cervical cutaneous, medial saphenous fasciocutaneous or musculofasciocutaneous, caudal superficial epigastric cutaneous, trapezius muscle or musculocutaneous, caudal sartorius muscle, latissimus dorsi muscle or musculocutaneous, cranial abdominal myoperitoneal, carpal footpad, digital footpad, and vascularized ulnar bone flaps. A total of 53 of 57 flaps (93%) survived. There was a significant relationship between flap failure and level of assistant surgeon experience (P < .05). Latissimus dorsi flaps were significantly more likely to fail when compared with pooled data from all other flap types (P < .01). CONCLUSIONS: The success of microvascular tissue transfer in this case series compares favorably with those reported in human reconstructive microsurgery. Both the primary and assistant surgeon should be practiced in microsurgical technique. Failure of latissimus dorsi flaps was not likely caused by an inherently deficient flap design, but was more likely attributed to the location and severity of trauma at the recipient site, the difficulty in isolating suitable recipient vessels for anastomosis or the absence of a trained assistant surgeon during these procedures. Clinical Relevance-This retrospective study documents the successful application of microvascular technique in a series of clinical cases requiring tissue reconstruction.

Anastomosis, Surgical↗

Focal myasthenia gravis as a paraneoplastic syndrome of canine thymoma: improvement following thymectomy.

A 10-year-old, neutered male cocker spaniel-cross experienced regurgitation, dry retching, and weight loss. A large, mediastinal mass and dilatation of the esophagus were seen on thoracic radiographs. Cytological, histopathological, immunohistochemical, and serological findings were consistent with a lymphoepithelial thymoma and focal, esophageal myasthenia gravis. Surgical removal of the mass resulted in rapid resolution of the megaesophagus and a decrease in serum acetylcholine-receptor antibody concentration. The dog was clinically normal until the thymoma recurred six months postoperatively. Clinical signs, diagnostic evaluation, management, and treatment of a dog with thymoma and megaesophagus are described.

Animals↗

Immunoscintigraphic detection of primary and metastatic spontaneous canine osteosarcoma with F(ab')2 fragments of osteosarcoma-associated monoclonal antibody TP-1.

Monoclonal antibody TP-1 has been shown to bind selectively to human and canine osteosarcoma cells in vitro using immunohistochemical stains. This report describes the in vivo administration of radioiodinated F(ab')2 fragments of monoclonal antibody TP-1 in dogs with primary and/or metastatic spontaneous osteosarcoma. Two dogs were injected with 131labeled F(ab')2 TP-1 and two dogs were injected with 123labeled antibody fragments. Immunoscintigraphy successfully demonstrated the radiolabeled antibody fragments in 6/6 known primary or metastatic lesions and in addition detected 4 metastatic lesions not diagnosed by conventional radiographs. Concurrent imaging of 99mTc labeled autologous erythrocytes in two dogs confirmed that the accumulation of radiolabeled antibody fragments was independent of the blood pool. There was no immunoscintigraphic evidence of localization of radioiodine to normal organs or tissues other than those expected to accumulate free iodine. The present study has demonstrated the potential of monoclonal antibody TP-1 F(ab')2 fragments for early detection of metastatic spread of spontaneous osteosarcoma.

Animals↗