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Professor Nick Bacon

Professor of Surgical Oncology

My publications


Webster JD, Dennis MM, Dervisis N, Heller J, Bacon NJ, Bergman PJ, Bienzle D, Cassali G, Castagnaro M, Cullen J, Esplin DG, Peña L, Goldschmidt MH, Hahn KA, Henry CJ, Hellmén E, Kamstock D, Kirpensteijn J, Kitchell BE, Amorim RL, Lenz SD, Lipscomb TP, McEntee M, McGill LD, McKnight CA, McManus PM, Moore AS, Moore PF, Moroff SD, Nakayama H, Northrup NC, Sarli G, Scase T, Sorenmo K, Schulman FY, Shoieb AM, Smedley RC, Spangler WL, Teske E, Thamm DH, Valli VE, Vernau W, von Euler H, Withrow SJ, Weisbrode SE, Yager J, Kiupel M (2011) Recommended guidelines for the conduct and evaluation of prognostic studies in veterinary oncology, Veterinary Pathology 48 (1) pp. 7-18
There is an increasing need for more accurate prognostic and predictive markers in veterinary oncology because of an increasing number of treatment options, the increased financial costs associated with treatment, and the emotional stress experienced by owners in association with the disease and its treatment. Numerous studies have evaluated potential prognostic and predictive markers for veterinary neoplastic diseases, but there are no established guidelines or standards for the conduct and reporting of prognostic studies in veterinary medicine. This lack of standardization has made the evaluation and comparison of studies difficult. Most important, translating these results to clinical applications is problematic. To address this issue, the American College of Veterinary Pathologists' Oncology Committee organized an initiative to establish guidelines for the conduct and reporting of prognostic studies in veterinary oncology. The goal of this initiative is to increase the quality and standardization of veterinary prognostic studies to facilitate independent evaluation, validation, comparison, and implementation of study results. This article represents a consensus statement on the conduct and reporting of prognostic studies in veterinary oncology from veterinary pathologists and oncologists from around the world. These guidelines should be considered a recommendation based on the current state of knowledge in the field, and they will need to be continually reevaluated and revised as the field of veterinary oncology continues to progress. As mentioned, these guidelines were developed through an initiative of the American College of Veterinary Pathologists' Oncology Committee, and they have been reviewed and endorsed by the World Small Animal Veterinary Association. © The American College of Veterinary Pathologists 2011.
Kim SE, Giglio RF, Reese DJ, Reese SL, Bacon NJ, Ellison GW (2013) Comparison of computed tomographic angiography and ultrasonography for the detection and characterization of portosystemic shunts in dogs., Vet Radiol Ultrasound 54 (6) pp. 569-574
The purpose of this retrospective study was to compare the accuracy of computed tomographic angiography (CTA) and abdominal ultrasonography in detecting and characterizing portosystemic shunts (PSS) in dogs. Medical records of 76 dogs that underwent CTA and/or abdominal ultrasonography suspected to have PSS were reviewed. Presence or absence, and characterization of PSS (when present) on CTA were reviewed by a board-certified veterinary radiologist that was blinded to the clinical findings. The abdominal ultrasonography findings were reviewed from the medical records. Visualization and description of the origin and insertion of PSS on CTA and abdominal ultrasonography were related with laboratory, surgical, or mesenteric portographic confirmation of the presence or absence of PSS. The sensitivity for detection of PSS with CTA (96%) was significantly higher than abdominal ultrasonography (68%; P
Cuddy LC, Bacon NJ, Coomer AR, Jeyapaul CJ, Sheppard BJ, Winter MD (2010) Excision of a congenital laryngeal cyst in a five-month-old dog via a lateral extraluminal approach., J Am Vet Med Assoc 236 (12) pp. 1328-1333
CASE DESCRIPTION: A 5-month-old neutered male Golden Retriever was evaluated because of moderate stridor, exercise intolerance, and dyspnea. The dog had been neutered 3 weeks previously, and the referring veterinarian identified a large fluid-filled swelling on the left lateral aspect of the larynx during anesthetic intubation for that surgery. The referring veterinarian drained fluid from the mass by use of needle centesis via the oral cavity, which resulted in temporary improvement in clinical signs; however, the clinical signs returned soon thereafter. CLINICAL FINDINGS: A large, soft, spherical mass was located between the left arytenoid and thyroid cartilages and axial to the left ceratohyoid bone, thus causing partial obstruction of the rima glottidis. Laryngoscopic examination, computed tomography (CT), and cytologic evaluation of aspirates performed before surgery; examination during surgery; and histologic evaluation of tissues following surgical excision confirmed the diagnosis of a laryngeal cyst. TREATMENT AND OUTCOME: Complete surgical excision was successfully performed via a lateral extraluminal approach to the larynx. One week after surgery, the dog coughed only occasionally. Twelve months after surgery, the owner reported that the dog was clinically normal with no recurrence of clinical signs, and laryngoscopic examination revealed no recurrence of the cyst or other pathological changes in the laryngeal region. CLINICAL RELEVANCE: Congenital laryngeal cysts are rarely reported in domestic animals. The information provided here described the CT appearance of a laryngeal cyst and the use of CT in diagnosis and surgical planning. Congenital laryngeal cysts can be resected via a lateral submucosal approach.
Bacon NJ (2013) Primary Hyperparathyroidism, In: Small Animal Soft Tissue Surgery pp. 1-16
© 2013 John Wiley & Sons, Ltd.The parathyroid glands in dogs and cats are tan-colored ovoid structures closely associated with each thyroid gland. Parathyroid hormone (PTH) release is controlled by calcium receptors on the chief cells in the parathyroid glands in response to hypocalcemia. PTH has a short half-life (3-5 min) in serum and so a steady rate of secretion is necessary to maintain serum PTH concentrations. Natural variations in PTH concentration occur in healthy dogs. Exploratory surgery with parathyroidectomy in dogs with primary hyperparathyroidism serves as both a diagnostic test and definitive therapy. Surgery should be advocated to reduce the risk of urolithiasis and urinary tract infection, as well as improving the clinical signs seen with hypercalcemia such as polydipsia, polyuria, weakness, and decreased appetite. Surgical excision alone is the most widely performed treatment for primary hyperparathyroidism and a cure rate of 94% is reported if all autonomously functioning parathyroid tissue is removed.
Kligman KC, Kim SE, Winter MD, Bacon NJ, Krellner HL, Levy JK (2009) What is your diagnosis? Synovial cysts., J Am Vet Med Assoc 235 (8) pp. 945-946
Boston SE, Duerr F, Bacon N, Larue S, Ehrhart EJ, Withrow S (2007) Intraoperative radiation for limb sparing of the distal aspect of the radius without transcarpal plating in five dogs., Vet Surg 36 (4) pp. 314-323
OBJECTIVES: To evaluate intraoperative irradiation (IORT) as a method of limb spare with preservation of the radiocarpal joint. STUDY DESIGN: Prospective case series. ANIMALS: Dogs (n=5) with stage II sarcoma of the distal aspect of the radius. METHODS: A bone segment containing the tumor was isolated surgically, treated by IORT, reimplanted, and secured by internal fixation. In 1 dog, the postradiation tumor bed was curetted and filled with bone cement. Dogs were administered alternating adriamycin and carboplatin starting 2 weeks after IORT and monitored at regular intervals. RESULTS: Four dogs had osteosarcoma and 1 had undifferentiated sarcoma. Implant failure (n=3), deep tissue infection (3), and pathologic fracture (3) resulted in amputation (3) or pancarpal plating (2). The dog with undifferentiated sarcoma was euthanatized because of suspected tumor recurrence 4 months postoperatively. Osteotomy healing was documented by radiography (1), histopathology (2), or by direct observation (2). CONCLUSIONS: A technique for limb-sparing surgery of the distal portion of the radius in dogs using IORT had advantages include healing of the autograft and a source for a perfectly fitting autograft but did not appear to offer any advantage with respect to infection rate. Long-term preservation of the radiocarpal joint was not successful. CLINICAL RELEVANCE: It was not possible to preserve the function of the radiocarpal joint and so this technique cannot be recommended currently. Further study is needed to evaluate whether or not IORT can be considered in combination with pancarpal plating and possibly curettage and cementation of the tumor to prevent subchondral bone collapse.
Sissener TR, Bacon NJ, Friend E, Anderson DM, White RA (2006) Combined clotrimazole irrigation and depot therapy for canine nasal aspergillosis., J Small Anim Pract 47 (6) pp. 312-315
OBJECTIVES: To evaluate the effect of short duration 1 per cent clotrimazole flush when combined with 1 per cent clotrimazole cream instilled into the frontal sinuses for the treatment of nasal aspergillosis in 14 dogs. METHODS: Fourteen dogs with clinical, radiological, serological and rhinoscopic findings consistent with nasal aspergillosis were treated by frontal sinus trephination and a short, five-minute flushing of 1 per cent topical clotrimazole solution followed by a 1 per cent clotrimazole cream instilled as a depot agent. RESULTS: Twelve of the 14 dogs (86 per cent) responded well to treatment and either had no clinical signs after treatment or had signs consistent with mild rhinitis during a minimum follow-up period of six months. Only one dog required multiple treatments. Treatment was well tolerated by all patients, with minimal complications. CLINICAL SIGNIFICANCE: This treatment compares favourably to previously published data using one-hour topical clotrimazole or enilconazole flushing treatment protocols. The treatment technique significantly reduced treatment time under anaesthesia.
Guerios SD, Silva DM, Souza CHM, Bacon NJ (2015) Surgical placement and management of jugular vascular access ports in dogs and cats: description of technique, REVISTA COLOMBIANA DE CIENCIAS PECUARIAS 28 (3) pp. 265-271 UNIV ANTIOQUIA, FAC CIENCIAS AGRARIAS
Rubin JA, Kim SE, Bacon NJ (2013) Traumatic tympanic bulla fracture., J Small Anim Pract 54 (11) pp. 605-609
A Pekingese dog was presented for evaluation of head trauma with ventral head and neck swelling, puncture wounds, palpable mandibular fractures, and loss of menace, severe miosis, and loss of palpebral reflex of the right eye. Computed tomography confirmed multiple mandibular and zygomatic fractures, a right ear canal avulsion, and a complete right tympanic bulla fracture with ventral displacement. The tympanic bulla fracture was managed conservatively. Topical lubrication and antibiotic ointment was prescribed for the right eye. A subtotal hemimandibulectomy was performed to address the mandibular fractures. A temporary oesophagostomy feeding tube was placed. No short-term complications developed as a result of the fractured bulla and avulsed ear canal being left in situ, and no complications were reported 18 months after the injury. To the authors' knowledge this is the first report of a traumatic tympanic bulla fracture in the dog.
Parfitt SL, Milner RJ, Salute ME, Hintenlang DE, Farese JP, Bacon NJ, Bova FJ, Rajon DA, Lurie DM (2011) Radiosensitivity and capacity for radiation-induced sublethal damage repair of canine transitional cell carcinoma (TCC) cell lines., Vet Comp Oncol 9 (3) pp. 232-240
Understanding the inherent radiosensitivity and repair capacity of canine transitional cell carcinoma (TCC) can aid in optimizing radiation protocols to treat this disease. The objective of this study was to evaluate the parameters surviving fraction at 2 Gy (SF(2) ), ±/² ratio and capacity for sublethal damage repair (SLDR) in response to radiation. Dose-response and split-dose studies were performed using the clonogenic assay. The mean SF(2) for three established TCC cell lines was high at 0.61. All the three cell lines exhibited a low to moderate ±/² ratio, with the mean being 3.27. Two cell lines exhibited statistically increased survival at 4 and 24 h in the dose-response assay. Overall, our results indicate that the cell lines are moderately radioresistant, have a high repair capacity and behave similarly to a late-responding normal tissue. These findings indicate that the radiation protocols utilizing higher doses with less fractionation may be more effective for treating TCC.
Dennis MM, McSporran KD, Bacon NJ, Schulman FY, Foster RA, Powers BE (2011) Prognostic factors for cutaneous and subcutaneous soft tissue sarcomas in dogs, Veterinary Pathology 48 (1) pp. 73-84
Soft tissue sarcomas (STSs) develop from mesenchymal cells of soft tissues, and they commonly occur in the skin and subcutis of the dog. Although phenotypically diverse with frequently controversial histogenesis, STSs are considered as a group because they have similar features microscopically and clinically. Following resection, local recurrence rates are low in general but vary according to histologic grade and completeness of surgical margins. Complete margins predict nonrecurrence. Even most grade I STSs with "close" margins will not recur, but propensity for recurrence increases with grade. The frequency of metastasis has not been accurately estimated, but it is believed to be rare for grade I STSs and most likely to occur with grade III STSs. However, metastasis does not necessarily equate with poor survival. High mitotic index is prognostic for reduced survival time. Further research is needed to determine more precise estimates for recurrence rates and survival as related to completeness of surgical margins and to delineate potential differences in metastatic rate and median survival time between grades. Other potential indicators of prognosis that presently require further investigation include histologic type, tumor dimension, location, invasiveness, stage, markers of cellular proliferation, and cytogenetic profiles. Common issues limiting prognostic factor evaluation include biases from retrospective studies, small sample sizes, poor verification of metastasis, inconsistent STS classification and use of nomenclature, difficulties in differentiating STS phenotype, and diversity of the study population (stage of disease and treatment status). © The American College of Veterinary Pathologists 2011.
Amsellem PM, Selmic LE, Wypij JM, Bacon NJ, Culp WTN, Ehrhart NP, Powers BE, Stryhn H, Farese JP (2014) Appendicular osteosarcoma in small-breed dogs: 51 cases (1986-2011), Journal of the American Veterinary Medical Association 245 (2) pp. 203-210
Objective-To describe outcomes for small-breed dogs with appendicular osteosarcoma. Design-Multi-institutional retrospective case series. Animals-51 small-breed dogs. Procedures-Records from participating Veterinary Society of Surgical Oncology members were searched for dogs that weighed d 15 kg (33 lb) with a histologic diagnosis of appendicular osteosarcoma. The Kaplan-Meier method was used to determine median survival times (MSTs), and Cox regression was performed to identify variables associated with survival time. Results-Tumors were most commonly located on the humerus (n = 15) and femur (14). Of the 51 study dogs, 9 were treated nonsurgically, 16 underwent amputation of the affected limb only, and 26 underwent curative-intent treatment, with MSTs of 112, 257, and 415 days, respectively. The MST did not differ significantly between dogs in the amputation-only and curative-intent groups. For dogs in the nonsurgical group, MST decreased significantly as the tumor histologic score increased. For dogs in the amputation-only group, MST decreased as body weight increased. Conclusions and Clinical Relevance-For the small-breed dogs with appendicular osteosarcoma of the present study, tumor histologic grade and mitotic index were subjectively lower and MST following amputation of the affected limb without adjuvant chemotherapy was longer, compared with those for similarly affected larger dogs. Results indicated no significant advantage in MST for dogs that underwent curative-intent treatment versus dogs that underwent amputation only, and further investigation of the importance of adjuvant chemotherapy is warranted.
Bacon NJ, Oni O, White RA (2002) Treatment of urethral sphincter mechanism incompetence in 11 bitches with a sustained-release formulation of phenylpropanolamine hydrochloride., Vet Rec 151 (13) pp. 373-376
Between 1995 and 1999, urethral sphincter mechanism incompetence was diagnosed in 11 bitches. They had been treated with phenylpropanolamine hydrochloride at the recommended dose rate, but had shown no response or had become refractory to treatment. They were treated with phenylpropanolamine hydrochloride in a sustained-release formulation combined with diphenylpyraline hydrochloride. The urinary incontinence resolved fully in six of the bitches, two of which remained continent after the treatment was withdrawn; two showed a marked improvement on daily treatment, but the other three bitches failed to respond and underwent colposuspension.
Bacon NJ, Farese JP (2013) Urinary Tract, pp. 365-382
Schmidt AF, Groenwold RHH, Amsellem P, Bacon N, Klungel OH, Hoes AW, de Boer A, Kow K, Maritato K, Kirpensteijn J, Nielen M (2015) Which dogs with appendicular osteosarcoma benefit most from chemotherapy after surgery? Results from an individual patient data meta-analysis, PREVENTIVE VETERINARY MEDICINE 125 pp. 116-125 ELSEVIER SCIENCE BV
Novello L, Carobbi B, Bacon NJ, White RA (2008) Hypobaric intrathecal anaesthesia for partial hemipelvectomy in a dog., Vet Comp Orthop Traumatol 21 (1) pp. 89-93
OBJECTIVE: To report the intrathecal use of a hypobaric anaesthetic solution for partial hemipelvectomy in a nine-year-old, neutered female, Golden Retriever dog, weighing 34 kg. METHODS: Under inhalational anaesthesia, with the dog lying in lateral recumbency and the surgical side uppermost, 1.9 ml of a hypobaric solution containing 3.42 mg of bupivacaine and 0.66 mg of morphine were administered in the subarachnoid space at L5-6 level 30 minutes before surgery. Following the intrathecal injection the dog was maintained for five minutes in a 10 degrees head-down position, then for three minutes in a 10 degrees head-up position. RESULTS: Apart from a transient increase in heart and respiratory rates during resection of the sartorius muscle, which was treated with a plasma Target Controlled Infusion (TCI) of fentanyl, spinal anaesthesia provided cardiovascular stability and excellent relaxation of the surgical site. Neither motor blockade nor proprioceptive deficit were apparent in the contra-lateral hind limb at recovery, 200 minutes after injection. Postoperatively, rescue analgesia was not required in the 48 hours following surgery. CLINICAL SIGNIFICANCE: In dogs, the use of intrathecal hypobaric bupivacaine and morphine as a part of a balanced anaesthetic protocol should be considered during unilateral major orthopaedic surgeries of the pelvis and hind limb, as it allowed a reduction in the dose administered compared to isobaric solutions, providing selective spinal anaesthesia, excellent long-lasting analgesia, and rapid recovery of ambulation.
Schmidt AF, Nielen M, Klungel OH, Hoes AW, de Boer A, Groenwold RHH, Kirpensteijn J, Amsellem P, Bacon N, Berg J, Kow K, Kurzman I, Maritato K, Moore A, Morello E, Sottnik J, Vail D (2013) Prognostic factors of early metastasis and mortality in dogs with appendicular osteosarcoma after receiving surgery: An individual patient data meta-analysis, Preventive Veterinary Medicine 112 (3-4) pp. 414-422
Recently an aggregated data meta-analysis showed that serum alkaline phosphatase (SALP) and proximal humerus location are predictors for shorter survival in canine osteosarcoma. To identify additional prognostic factors of mortality and metastasis an individual patient data meta-analysis (IPDMA) was conducted. Individual patient data from 20 studies, identified via the VSSO society, were pooled. Univariable and multivariable hazard ratios (HR) for metastasis and mortality were assessed, using stratified Cox models. The study included 1405 dogs who received surgical treatment, of which the metastasis status was measured in 1155 dogs and mortality status in 1336 dogs; median survival was 256 days. High versus normal SALP and weight (kg) were associated with an increase in hazard of metastasis [HR 1.34 (95%CI 1.07; 1.68) and HR 1.02 (per kg increase) (95%CI 1.01; 1.03)] and for mortality [HR 1.43 (95%CI 1.16; 1.77) and HR 1.02 (95%CI 1.01; 1.02)]. Distal radius tumor was associated with a lower hazard of metastasis compared to other locations: HR 0.75 (95%CI 0.58; 0.96). Proximal humerus and distal femur or proximal tibia location were related with an increased mortality: HR 1.53 (95%CI 1.26; 1.84) and HR 1.23 (95%CI 1.01; 1.49) compared to other locations. Older age (years) was associated with a higher hazard for mortality [HR 1.06 per year (95%CI 1.03; 1.09)] but not for metastasis: HR 1.03 (95%CI 0.99; 1.06). These results confirm findings from a recent aggregated data meta-analysis and (in addition) showed that tumor location, SALP, weight were prognostic factors for both mortality and metastasis. Age was a prognostic factor for mortality but not for metastasis. © 2013 Elsevier B.V.
Bacon NJ, Ehrhart NP, Dernell WS, Lafferty M, Withrow SJ (2008) Use of alternating administration of carboplatin and doxorubicin in dogs with microscopic metastases after amputation for appendicular osteosarcoma: 50 cases (1999-2006)., J Am Vet Med Assoc 232 (10) pp. 1504-1510
OBJECTIVE: To evaluate the efficacy and toxicity of an alternating carboplatin and doxorubicin chemotherapy protocol in dogs with putative microscopic metastases after amputation for appendicular osteosarcoma and assess patient-, tumor-, and treatment-related factors for associations with prognosis. DESIGN: Retrospective case series. ANIMALS: 50 client-owned dogs. PROCEDURES: Records of dogs that underwent amputation for appendicular osteosarcoma and received an alternating carboplatin and doxorubicin chemotherapy protocol were reviewed. Dogs had full staging and were free of detectable metastases prior to chemotherapy. Data on disease-free interval (DFI), survival time, and toxicoses were retrieved from medical records and owner or referring veterinarian communications. RESULTS: Median DFI was 202 days. Median survival time was 258 days. Twenty-nine (58%) dogs completed the protocol as planned, and the rest were withdrawn typically because of metastases or toxicoses. Grade 3 or 4 myelosuppression was reported in 9 of 50 (18%) dogs and grade 3 or 4 gastrointestinal toxicosis in 6 of 50 (12%) dogs. There were no chemotherapy-related fatalities. Univariate factors associated with significant improvement in DFI included tumor location (radius), receiving doxorubicin as the first drug, starting chemotherapy more than 14 days after amputation, and no rib lesions on preamputation bone scans. Multivariate factors associated with a significant improvement in survival time were tumor location (radius) and completing chemotherapy. CONCLUSIONS AND CLINICAL RELEVANCE: Alternating administration of carboplatin and doxorubicin resulted in DFI and survival time similar to those reported for single-agent protocols. Clients should be counseled regarding the likelihood of toxicoses. Relevance of sequence and timing of starting chemotherapy should be further evaluated.
Gear RNA, Bacon NJ, Langley-Hobbs S, Watson PJ, Woodger N, Herrtage ME (2006) Anniculitis, polyarthritis and osteomyelitis associated with pancreatic neoplasia in two dogs, Journal of Small Animal Practice 47 (7) pp. 400-404
A 12-year-old crossbred dog (case 1) and a 12-year-old Shetland sheepdog (case 2) were presented with a history of lameness and distal limb swelling. Physical examination revealed joint effusions and asymmetrical swellings of the extremities. In case 1, a diagnosis of arthritis and cellulitis was made on fine-needle aspiration biopsy of the synovium and subcutis. In case 2, bone biopsies and synovial aspirates diagnosed osteomyelitis and arthritis. A diagnosis of pancreatic disease was made on the findings of marked elevations of serum lipase concentrations and ultrasonographic identification of pancreatic masses in both cases. Both the cases were non-responsive to symptomatic management and were subsequently euthanased. Postmortem examination confirmed the diagnosis of panniculitis, arthritis and osteomyelitis in both cases. A pancreatic exocrine adenoma was identified in case 1 and a pancreatic adenocarcinoma with widespread metastases in case 2. To the authors' knowledge the association of panniculitis, polyarthritis and osteomyelitis with pancreatic disorders has not been reported previously in canine clinical cases. © 2006 British Small Animal Veterinary Association.
Bacon NJ, Kamstock DA (2013) Spleen, pp. 387-392
Bacon NJ, Dernell WS, Ehrhart N, Powers BE, Withrow SJ (2007) Evaluation of primary re-excision after recent inadequate resection of soft tissue sarcomas in dogs: 41 cases (1999-2004)., J Am Vet Med Assoc 230 (4) pp. 548-554
OBJECTIVE: To determine the efficacy of primary re-excision alone for treatment of soft tissue sarcomas after recent incomplete resection, the frequency and clinical importance of detecting residual tumor in resected scars, and prognostic factors associated with the procedure. DESIGN: Retrospective case series. ANIMALS: 41 dogs. PROCEDURES: Medical records of dogs that had undergone recent incomplete excision of a soft tissue sarcoma at a referring veterinary practice and subsequent re-excision of the scar at the Colorado State University Veterinary Medical Center were reviewed. Owners and referring veterinarians were contacted for follow-up information. Slides from re-excised specimens were reviewed. Dogs that underwent radiation therapy after the re-excision procedure were excluded. RESULTS: 41 dogs met the inclusion criteria, and long-term follow-up information was available for 39 dogs. Median follow-up time was 816 days. Local recurrence of tumor developed in 6 of 39 (15%) dogs, and distant metastasis occurred in 4 of 39 (10%) dogs. Healthy tissue margins of 0.5 to 3.5 cm were achieved at re-excision. Residual tumor was identified in 9 of 41 (22%) resected scars. No tumor-, patient-, or treatment-related variables were associated with local recurrence except for the presence of liposarcoma or fibrosarcoma or whether fine-needle aspiration had been performed prior to surgery. CONCLUSIONS AND CLINICAL RELEVANCE: After incomplete resection of soft tissue sarcomas, resection of local tissue should be performed, even if excisable tissue margins appear narrow. A long-term favorable prognosis is achievable without radiation therapy or amputation. The presence of residual tumor in resected scar tissue should not be used to predict local recurrence.
Risselada M, Ellison GW, Bacon NJ, Polyak MM, van Gilder J, Kirkby K, Kim SE (2010) Comparison of 5 surgical techniques for partial liver lobectomy in the dog for intraoperative blood loss and surgical time., Vet Surg 39 (7) pp. 856-862
OBJECTIVE: To compare surgical time and intraoperative blood loss for 5 partial liver lobectomy techniques in the dog. STUDY DESIGN: Experimental in vivo study. ANIMALS: Dogs (n=10). METHODS: Five surgical techniques (SurgiTie(") ; LigaSure(") ; Ultracision(®) Harmonic Scalpel [UAS]; Suction+Clip; Suction+thoracoabdominal stapler [TA]) for partial liver lobectomy in dogs were evaluated and compared for total surgical time and intraoperative blood loss. Body weight, activated clotting time (ACT), heart rate, and intraoperative blood pressure (BP) were recorded. Blood loss was determined by adding the weight of the blood soaked sponges during surgery (1 g=1 mL) to the amount of suctioned blood (mL). Surgical time (in seconds) was determined from the start of the lobectomy until cessation of bleeding from the stump. Mean surgical time and mean blood loss for each technique were compared using a Tukey's multiple comparison test. RESULTS: No significant differences were found between dogs for weight, ACT, heart rate, and intraoperative BP. No complications were seen with the SurgiTie(") technique in 9 of 10 cases. There was no significant difference in surgical time between techniques however there was a significant difference for blood loss; the Suction+Clip method had significantly more blood loss than the other techniques. CONCLUSIONS: Skeletonization of the lobar vessels before individually clipping them (Suction+Clip) resulted in a higher blood loss than using Suction+TA, UAS, SurgiTie(") or the LigaSure(") device. The SurgiTie(") appears to be an acceptable method for partial liver lobectomy. CLINICAL RELEVANCE: Although skeletonization and individually clipping the vessels had the highest blood loss, it still was
Kirkby K, Wheeler J, Farese J, Ellison G, Bacon N, Sereda C, Lewis D (2009) Surgical views: Vacuum-assisted wound closure: application and mechanism of action., Compend Contin Educ Vet 31 (12) pp. E1-E7
Vacuum-assisted closure (VAC) is a wound management therapy that creates local negative pressure over a wound bed to promote healing. Benefits of VAC therapy include removal of fluid from the extravascular space, improved circulation, enhanced granulation tissue formation, increased bacterial clearance, and hastening of wound closure. This article describes the mechanism of action of VAC therapy, reviews application techniques, and lists potential complications and contraindications.
Kirkby KA, Wheeler JL, Farese JP, Ellison GW, Bacon NJ, Sereda CW, Lewis DD (2010) Surgical views: Vacuum-assisted wound closure: clinical applications., Compend Contin Educ Vet 32 (3) pp. E1-E6
Vacuum-assisted closure (VAC) is a wound management system that exposes a wound bed to local negative pressure to promote healing. Benefits of VAC therapy include removal of fluid from the extravascular space, improved circulation, enhanced granulation tissue formation, and increased bacterial clearance. VAC therapy has been used extensively in human patients to treat a variety of acute and chronic wound conditions. This article reviews the use of VAC therapy in a variety of wound conditions and describes our experiences with using VAC therapy in dogs and cats at the University of Florida.
Risselada M, Polyak MM, Ellison GW, Bacon NJ, Van Gilder JM, Coomer AR, Thieman KE (2010) Postmortem evaluation of surgery site leakage by use of in situ isolated pulsatile perfusion after partial liver lobectomy in dogs., Am J Vet Res 71 (3) pp. 262-267
OBJECTIVE: To evaluate postmortem surgery site leakage by use of in situ isolated pulsatile perfusion after partial liver lobectomies. ANIMALS: 10 healthy mixed-breed male dogs. PROCEDURES: Dogs were anesthetized, and 5 surgical techniques (pretied suture loop, energy-based sealer-divider, harmonic scalpel, suction with clip application, or suction with use of a thoracoabdominal stapler) were used to perform 5 partial liver lobectomies in each dog. Dogs were euthanatized, and the portal vein and hepatic artery were cannulated and perfused with a modified kidney perfusion machine (pulsatile flow for arterial perfusion and nonpulsatile flow for portal perfusion). Lobectomy sites were inspected for leakage of perfusate, and time until detection of leakage was recorded. The techniques in each dog were ranked on the basis of time until leakage. Time until leakage and rankings for each surgical technique were analyzed by use of an ANOVA. RESULTS: Leakage of perfusate was recorded in 44 lobes at supraphysiologic pressures. Of the 6 lobes without leakage, a pretied suture loop procedure was performed in 5 and a harmonic scalpel procedure was performed in 1. Time until leakage and the ranking differed significantly between the pretied suture loop and the other techniques. Time until leakage and ranking did not differ significantly among the other techniques. CONCLUSIONS AND CLINICAL RELEVANCE: Time until leakage of perfusate was greater for the pretied suture loop technique than for the other techniques, and that technique did not fail in 5 of 10 lobes. However, all techniques appeared to be safe for clinical use.
Wirth KA, Kow K, Salute ME, Bacon NJ, Milner RJ (2014) In vitro effects of Yunnan Baiyao on canine hemangiosarcoma cell lines., Vet Comp Oncol
Yunnan Baiyao is a Chinese herbal medicine that has been utilized for its anti-inflammatory, haemostatic, wound healing and pain relieving properties in people. It has been utilized in the veterinary profession to control bleeding in dogs with hemangiosarcoma (HSA) and has been anecdotally reported to prolong survival times in dogs with this neoplasm. This study evaluated the in vitro activity of Yunnan Baiyao against three canine HSA cell lines after treatment with increasing concentrations of Yunnan Baiyao (50, 100, 200, 400, 600 and 800 µg mL(-1) ) at 24, 48 and 72 h. Mean half maximum inhibitory concentration (IC50 ) at 72 h for DEN, Fitz, SB was 369.9, 275.9 and 325.3 µg mL(-1) , respectively. Caspase-3/7 activity increased in correlation with the IC50 in each cell line which was confirmed by the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL, APO-BRDU Kit; BD Biosciences, San Jose, CA, USA) assay. VEGF in cell supernatant was also quantified. Overall, the study found that Yunnan Baiyao causes dose and time dependent HSA cell death through initiation of caspase-mediated apoptosis, which supports future studies involving Yunnan Baiyao.
Boston SE, Bacon NJ, Culp WTN, Bhandal J, Bruce C, Cavanaugh RP, Hamilton MH, Lincoln JD, Liptak JM, Scharvogel S (2011) Outcome after Repair of a Sarcoma-Related Pathologic Fracture in Dogs: A Veterinary Society of Surgical Oncology Retrospective Study, VETERINARY SURGERY 40 (4) pp. 431-437 WILEY-BLACKWELL
Coomer A, Farese J, Milner R, Liptak J, Bacon N, Lurie D (2009) Radiation therapy for canine appendicular osteosarcoma., Vet Comp Oncol 7 (1) pp. 15-27
Radiation therapy (RT) for the management of canine appendicular osteosarcoma (OSA) can be described as either palliative- or curative intent. Palliative RT uses coarsely fractionated external beam RT or radiopharmaceuticals to provide relief of pain and lameness associated with OSA while resulting in minimal, if any, radiation-induced acute adverse effects. Limb amputation and chemotherapy are considered (together) the standard of care for curative-intent treatment of canine appendicular OSA. When limb amputation is not possible, RT can be used for limb sparing and is supplemented with chemotherapy for presumed micrometastatic disease. Fractionated tumour irradiation with curative intent appears to be ineffective and local disease control can more likely be achieved when stereotactic radiosurgery or intra-operative extracorporeal irradiation is combined with strict case selection and adjunctive chemotherapy. The availability of limb-sparing RT is limited by experience and availability of specialised equipment. When planned and administered appropriately, radiation-associated adverse effects are often mild and self-limiting.
Covey JL, Farese JP, Bacon NJ, Schallberger SP, Amsellem P, Cavanaugh RP, Milner RJ (2014) Stereotactic Radiosurgery and Fracture Fixation in 6 Dogs With Appendicular Osteosarcoma,VETERINARY SURGERY 43 (2) pp. 174-181 WILEY-BLACKWELL
Fahey CE, Milner RJ, Kow K, Bacon NJ, Salute ME (2013) Apoptotic effects of the tyrosine kinase inhibitor, masitinib mesylate, on canine osteosarcoma cells., Anticancer Drugs 24 (5) pp. 519-526
Osteosarcoma (OSA) is the most common primary bone tumor in dogs and the guarded prognosis highlights the necessity to find new treatments. Masitinib mesylate is a highly selective tyrosine kinase inhibitor that predominantly targets c-Kit and PDGFR-±/². This study evaluated the in-vitro activity of masitinib against three canine OSA cell lines after treatment with increasing concentrations of masitinib (0.1-50 µmol/l) at 24, 48, and 72 h. The IC50 values at 72 h for the three OSA cell lines (POS, HMPOS, and COS31) were determined to be 11.04, 7.09, and 9.74 µmol/l, respectively. In addition, increases in caspase-3/7 activity and transferase dUTP nick end labeling-positive cells indicated apoptotic cell death. Because increased levels of vascular endothelial growth factor are found in dogs with OSA, vascular endothelial growth factor in the supernatant was quantified. Overall, the study found that masitinib causes dose-time dependent OSA cell death in vitro through initiation of caspase-mediated apoptosis, which supports future OSA clinical trials.
Kirkby KA, Wheeler JL, Farese JP, Ellison GW, Bacon NJ, Sereda CW, Lewis DD (2009) Vacuum-assisted wound closure: Application and mechanism of action, Compendium: Continuing Education For Veterinarians 31 (12) pp. 568-576
Vacuum-assisted closure (VAC) is a wound management therapy that creates local negative pressure over a wound bed to promote healing. Benefits of VAC therapy include removal of fluid from the extravascular space, improved circulation, enhanced granulation tissue formation, increased bacterial clearance, and hastening of wound closure. This article describes the mechanism of action of VAC therapy, reviews application techniques, and lists potential complications and contraindications.
Kelsey KL, Kubicek LN, Bacon NJ, Torres T, Robertson SA (2017) Neuromuscular blockade and inspiratory breath hold during stereotactic body radiation therapy for treatment of heart base tumors in four dogs, Journal of the American Veterinary Medical Association 250 (2) pp. 199-204
4 dogs were examined because of pleural effusion and ventricular tachycardia,
coughing and supraventricular tachycardia, appendicular osteosarcoma,
and syncopal episodes.
In all 4 dogs, a heart base tumor was identified by means of thoracic CT.
In all 4 dogs, the heart base tumors were treated by means of stereotactic
body radiation therapy. Dogs were anesthetized, and neuromuscular
blockade was achieved with atracurium or vecuronium. A circle rebreathing
system with 15 m (50 feet) of anesthetic tubing coursing through the vault
wall was used to connect the patient to the anesthesia machine, which was
located in the control room. After a brief period of hyperventilation, an
inspiratory breath was held at 20 cm H2O for the duration of beam delivery.
Each beam delivery lasted between 30 and 100 seconds. Immediately following
the breath hold, assisted ventilation was resumed. Mean treatment
delivery time for each patient was 26 minutes; mean total anesthesia time
was 89 minutes. All patients recovered without complications. There was
no evidence of hemoglobin desaturation or hypercapnia during the anesthetic
Bacon NJ, Gilbert RL, Bostock DE, White RA (2003) Total ear canal ablation in the cat: indications, morbidity and long-term survival., J Small Anim Pract 44 (10) pp. 430-434
Fifty-two total ear canal ablation (TECA) procedures in 44 cats were reviewed. The indication for surgery was neoplasia in 41 per cent of the cats, 86 per cent of which had ceruminous gland adenocarcinoma. Chronic inflammatory or polypoid disease accounted for 50 per cent of surgical procedures. Postoperative complications included Horner's syndrome (42 per cent) and facial paralysis (56 per cent) and these were permanent in 14 per cent and 28 per cent of cases, respectively, with the rest resolving in the ensuing weeks or months. The higher incidence of Horner's syndrome and facial paralysis in the cat, compared to the dog, was attributed to greater fragility of the feline tympanic plexus and facial nerve. The median survival time of cats with ceruminous gland adenocarcinoma was 50-3 months, and did not differ significantly from that for inflammatory or polypoid disease. A potential prognostic indicator for this tumour was the mitotic index (MI): cases with MI or = 3.
Cavanaugh RP, Farese JP, Bacon NJ, Lurie DM, Milner RJ (2011) Oronasal fistula repair utilizing a temporalis muscle flap in a dog with severe trismus., J Am Anim Hosp Assoc 47 (6) pp. 447-454
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.
Farese JP, Kirpensteijn J, Kik M, Bacon NJ, Waltman SS, Seguin B, Kent M, Liptak J, Straw R, Chang MN, Jiang Y, Withrow SJ (2009) Biologic behavior and clinical outcome of 25 dogs with canine appendicular chondrosarcoma treated by amputation: a Veterinary Society of Surgical Oncology retrospective study., Vet Surg 38 (8) pp. 914-919
OBJECTIVE: To characterize biologic behavior, clinical outcome, and effect of histologic grade on prognosis for dogs with appendicular chondrosarcoma treated by amputation alone. STUDY DESIGN: Case series. ANIMALS: Dogs (n=25) with appendicular chondrosarcoma. METHODS: Medical records were searched to identify dogs with appendicular chondrosarcoma treated by limb amputation alone. Information recorded included signalment, anatomic location, radiographic appearance, and development of metastasis. Histopathologic diagnosis was confirmed and graded (1, 2, or 3). Survival curves were generated by the Kaplan-Meier method and the association between covariates (gender, age, weight, and tumor grade) and survival were evaluated using the univariate proportional hazards model. RESULTS: Histopathology slides were available for 25 dogs. Rates of pulmonary metastasis were as follows: grade 1-0%, grade 2-31%, and grade 3-50%. Overall median survival time (MST) was 979 days. Age, weight, and sex were not significantly associated with survival (P=.16; .33; and .31, respectively). Survival was significantly associated with tumor grade (P=.008), with dogs with tumor grade of 1, 2, and 3 having MSTs of 6, 2.7, and 0.9 years, respectively. CONCLUSION: Canine appendicular chondrosarcoma can be treated effectively with amputation alone. Low to intermediate grade chondrosarcoma has a good prognosis, whereas high-grade tumors appear to behave aggressively. CLINICAL RELEVANCE: The overall prognosis for appendicular chondrosarcoma is better than that of appendicular osteosarcoma treated by amputation alone or in combination with chemotherapy.
Bacon N, Souza CHDM, Franz S (2016) Total cysto-prostatectomy: Technique description and results in 2 dogs, CANADIAN VETERINARY JOURNAL-REVUE VETERINAIRE CANADIENNE 57 (2) pp. 141-146 CANADIAN VET MED ASSOC
Bacon NJ, Anderson DM, Baines EA, White RAS (2002) Post-traumatic para-ureteral urinoma (uriniferous pseudocyst) in a cat, Veterinary and Comparative Orthopaedics and Traumatology 15 (2) pp. 123-126
A para-ureteral urinoma was diagnosed in a one year old domestic longhaired cat presented with signs of lethargy and abdominal distension three weeks after a road traffic accident. The urinoma was caused by chronic low-grade extravasation of urine from the left ureter into the retroperitoneal space, resulting in cellulitis producing a thick fibrous capsule around the urine. Left sided ureteronephrectomy with capsular resection and omentalisation was curative.
Covey JL, Farese JP, Bacon NJ, Schallberger SP, Amsellem P, Cavanaugh RP, Milner RJ (2014) Stereotactic radiosurgery and fracture fixation in 6 dogs with appendicular osteosarcoma.,Vet Surg 43 (2) pp. 174-181
OBJECTIVE: To evaluate clinical outcome of dogs with appendicular osteosarcoma (OSA) treated with stereotactic radiosurgery (SRS) and subsequent internal fixation of a pathologic fracture. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs with spontaneous-occurring appendicular OSA (n = 6). METHODS: Medical records (May 2002-January 2008) of dogs that had SRS for appendicular OSA were reviewed. Dogs were included if they had a pathologic fracture either before or after SRS and were treated with internal fixation. Signalment, history, physical examination findings, clinicopathologic data, diagnostic imaging findings, biopsy results, surgical complications, number of surgeries, adjuvant therapy, development of metastatic disease and cause of death were recorded. RESULTS: Six dogs met the inclusion criteria. Two dogs had a pathologic fracture at admission and 4 dogs developed a fracture after SRS with a mean ± SD time to fracture development of 6.25 ± 1.65 months. The first 3 fractures were repaired using an open approach and the latter three using minimally invasive percutaneous osteosynthesis (MIPO). Infection occurred in 5 dogs and implant failure in 3. Limb function was subjectively assessed as good in all dogs when the implants were stable and infections were subclinical. Survival times ranged from 364-897 days; 1 dog was lost to follow-up. CONCLUSIONS: Fracture repair using internal fixation should be considered a viable limb-sparing alternative for pathologic fractures that have been treated with SRS.
Thieman KM, Kirkby KA, Flynn-Lurie A, Grooters AM, Bacon NJ (2011) Diagnosis and treatment of truncal cutaneous pythiosis in a dog., J Am Vet Med Assoc 239 (9) pp. 1232-1235
CASE DESCRIPTION: A 4-year-old spayed female Boxer was evaluated for a cutaneous mass located on the dorsum. The mass had been present for 6 weeks and was increasing in size. CLINICAL FINDINGS: A mass of approximately 10 cm in diameter was detected on the dorsum cranial to the right ilial wing. Histologic examination of a tissue sample from the mass led to the diagnosis of cutaneous pythiosis. Computed tomography of the abdomen and the mass were performed and revealed a contrast-enhancing soft tissue mass of the dorsum and enlarged intra-abdominal lymph nodes. TREATMENT AND OUTCOME: The dog underwent surgical excision of the cutaneous mass, including 5-cm skin margins and deep margins of 2 fascial planes. The mass was completely excised on the basis of results of histologic examination of surgical margins. The dog received itraconazole and terbinafine by mouth for 3 months following surgery. Recheck examination at 20 months postoperatively showed no signs of recurrence of pythiosis at the surgical site. CLINICAL RELEVANCE: Aggressive surgical excision in combination with medical treatment resulted in a favorable long-term (> 1 year) outcome in this dog. Thorough workup including diagnostic imaging and lymph node evaluation is recommended. If surgery is to be performed, skin margins of 5 cm and deep margins of 2 fascial planes are recommended.
Batlivala TP, Bacon NJ, Avery AC, Barabas K, Gunn-Christie RG, Conway J, Avery PR (2010) Paraneoplastic T cell lymphocytosis associated with a thymoma in a dog., J Small Anim Pract 51 (9) pp. 491-494
A four-year-old male neutered Australian shepherd dog was diagnosed with a thymoma and concurrent mature T cell lymphocytosis. The lymphocytosis consisted of a mixed population of T cells expressing either CD4 or CD8 or neither marker, and the result of polymerase chain reaction for antigen receptor rearrangement was negative. The peripheral lymphocytosis resolved within 24 hours following thoracotomy and thymectomy. Similar cases have been reported in man, but the aetiology of the increased circulating lymphocytes remains unclear. Although peripheral lymphocytosis is an uncommon paraneoplastic syndrome associated with thymomas, thymoma should be considered as a differential when the increased lymphocytes consist of a mixed population of T cells.
Phelps HA, Kuntz CA, Milner RJ, Powers BE, Bacon NJ (2011) Radical excision with five-centimeter margins for treatment of feline injection-site sarcomas: 91 cases (1998-2002)., J Am Vet Med Assoc 239 (1) pp. 97-106
OBJECTIVE: To evaluate outcomes of radical excision of feline injection-site sarcomas (ISS) via assessment of local recurrence and metastasis rates, survival times, and complications associated with surgery. DESIGN: Retrospective case series. ANIMALS: 91 cats with ISS. PROCEDURES: Medical records of cats that had radical excision of ISS without adjunctive treatment were reviewed. Information extracted included sex, type of surgical procedure, histologic tumor grade, tumor diameter, time from tumor detection to definitive surgery, complications associated with surgery, whether tumors recurred locally or metastasized, and survival times. Diagnosis of ISS was histologically confirmed, and additional follow-up was performed. RESULTS: Overall median survival time was 901 days. Thirteen of 91 (14%) cats had local tumor recurrence; 18 (20%) cats had evidence of metastasis after surgery. Median survival time of cats with and without recurrence was 499 and 1,461 days, respectively. Median survival time of cats with and without metastasis was 388 and 1,528 days, respectively. Tumor recurrence and metastasis were significantly associated with survival time, whereas other examined variables were not. Major complications occurred in 10 cats, including 7 with incisional dehiscence. CONCLUSIONS AND CLINICAL RELEVANCE: Radical excision of ISS resulted in a metastasis rate similar to rates reported previously; the local recurrence rate appeared to be substantially less than rates reported after less aggressive surgeries, with or without adjuvant treatment. Major complication rates were similar to rates reported previously after aggressive surgical resection of ISS. Radical excision may be a valuable means of attaining an improved outcome in the treatment of feline ISS.
Jeffery ND, Talbot CE, Smith PM, Bacon NJ (2006) Acquired idiopathic laryngeal paralysis as a prominent feature of generalised neuromuscular disease in 39 dogs., Vet Rec 158 (1)
A retrospective evaluation of 17 dogs treated surgically for idiopathic acquired laryngeal paralysis demonstrated a marked variability in outcome, with many dogs continuing to exhibit weakness and exercise tolerance. In a subsequent prospective study, 22 consecutive affected dogs were tested for neurological deficits by neurological examination, electrodiagnostic evaluation, and blood analysis to measure thyroxine and thyroid-stimulating hormone and to detect any evidence of myasthenia gravis. Clinical neurological deficits and/or electrodiagnostic abnormalities were found in each case. There was limited evidence that specific neurological deficits were associated with a poor prognosis for full recovery of exercise tolerance. None of the dogs was positive for anti-acetylcholine receptor antibodies, and only three showed evidence of thyroid dysfunction.
Bacon NJ, White RA (2003) Extrahepatic biliary tract surgery in the cat: a case series and review., J Small Anim Pract 44 (5) pp. 231-235
Four cases of extrahepatic biliary tract surgery in the cat are described. The causes of the disease were inflammation of the gallbladder, distal common bile duct (CBD) or major duodenal papilla, and traumatic avulsion of the CBD. Bile peritonitis was present in two of the cats. Biliary enterostomy was performed in three cats, two of which were euthanased at five weeks and three months postsurgery; the third was alive at the time of writing, four months postsurgery. Cholecystectomy was curative in one cat. A literature review reveals high early mortality following biliary diversion, with only 50 per cent of cases surviving more than two weeks, and 23 per cent surviving more than six months. Surviving cats had repeated intermittent vomiting and anorexia that responded to antibiotics. No postoperative mortality was seen when biliary diversion was avoided. Whenever biliary enterostomy or temporary diversion methods are performed, a poorer prognosis should be offered due to the increased likelihood of postoperative complications and mortality.
McCally RE, Kim SE, Bacon NJ, Winter MD, Cords AA, Conway JA (2012) Surgical management of a subepiglottic thyroglossal duct cyst in a dog., J Am Anim Hosp Assoc 48 (3) pp. 198-202
A 2 yr old dog presented for dysphagia and coughing secondary to a 4 cm × 4 cm turgid subepiglottic mass. Cervical radiographs, an esophagram, and computed tomography confirmed the presence of a cystic mass that was not intimately associated with any surrounding structures. An incisional biopsy confirmed the cystic nature of the mass and helped to rule out a malignancy. A marginal surgical excision was performed via a ventral approach. Histopathology of the mass was consistent with a thyroglossal duct cyst. This is the first report of a thyroglossal duct cyst in this location in a dog. There was no recurrence of clinical signs 14 mo after surgery.
Bray JP, Worley DR, Henderson RA, Boston SE, Mathews KG, Romanelli G, Bacon NJ, Liptak JM, Scase TJ (2014) Hemipelvectomy: Outcome in 84 dogs and 16 cats. A veterinary society of surgical oncology retrospective study, Veterinary Surgery 43 (1) pp. 27-37
Objective: To report clinical findings, perioperative complications and long-term outcome in dogs and cats that had hemipelvectomy surgery for treatment of neoplasia. Study Design: Multi-institutional retrospective case series. Animals: Dogs (n=84) and cats (16). Methods: Medical records (January 2000 to December 2009) of dogs and cats that had hemipelvectomy at participating institutions were reviewed. Postoperative progress and current status of the patient at the time of the study was determined by either medical record review, or via telephone contact with the referring veterinarian or owner. Results: Complications were infrequent and usually minor. Hemorrhage was the main intraoperative complication; 2 dogs required blood transfusion. One dog developed an incisional hernia. In dogs, hemangiosarcoma had the worst prognosis with a median survival time (MST) of 179 days. MST for chondrosarcoma (1232 days), osteosarcoma (533 days), and soft tissue sarcoma (373 days) were not statistically different. Median disease-free interval (DFI) for local recurrence of all tumor types was 257 days. Cats had 75% survival at 1 year, which was significantly longer than dogs. Conclusions: Survival times for most tumor types can be good, but surgical margins should be carefully evaluated to ensure complete tumor removal. Adjuvant therapies may be advisable particularly for dogs to reduce rates of local recurrence or distant metastasis. © 2013 by The American College of Veterinary Surgeons.
Kamstock DA, Ehrhart EJ, Getzy DM, Bacon NJ, Rassnick KM, Moroff SD, Liu SM, Straw RC, McKnight CA, Amorim RL, Bienzle D, Cassali GD, Cullen JM, Dennis MM, Esplin DG, Foster RA, Goldschmidt MH, Gruber AD, Hellmén E, Howerth EW, Labelle P, Lenz SD, Lipscomb TP, Locke E, McGill LD, Miller MA, Mouser PJ, O'Toole D, Pool RR, Powers BE, Ramos-Vara JA, Roccabianca P, Ross AD, Sailasuta A, Sarli G, Scase TJ, Schulman FY, Shoieb AM, Singh K, Sledge D, Smedley RC, Smith KC, Spangler WL, Steficek B, Stromberg PC, Valli VE, Yager J, Kiupel M, American College of Veterinary Pathologists' Oncology Committee (2011) Recommended guidelines for submission, trimming, margin evaluation, and reporting of tumor biopsy specimens in veterinary surgical pathology., Vet Pathol 48 (1) pp. 19-31
Neoplastic diseases are typically diagnosed by biopsy and histopathological evaluation. The pathology report is key in determining prognosis, therapeutic decisions, and overall case management and therefore requires diagnostic accuracy, completeness, and clarity. Successful management relies on collaboration between clinical veterinarians, oncologists, and pathologists. To date there has been no standardized approach or guideline for the submission, trimming, margin evaluation, or reporting of neoplastic biopsy specimens in veterinary medicine. To address this issue, a committee consisting of veterinary pathologists and oncologists was established under the auspices of the American College of Veterinary Pathologists Oncology Committee. These consensus guidelines were subsequently reviewed and endorsed by a large international group of veterinary pathologists. These recommended guidelines are not mandated but rather exist to help clinicians and veterinary pathologists optimally handle neoplastic biopsy samples. Many of these guidelines represent the collective experience of the committee members and consensus group when assessing neoplastic lesions from veterinary patients but have not met the rigors of definitive scientific study and investigation. These questions of technique, analysis, and evaluation should be put through formal scrutiny in rigorous clinical studies in the near future so that more definitive guidelines can be derived.
Gear RN, Bacon NJ, Langley-Hobbs S, Watson PJ, Woodger N, Herrtage ME (2006) Panniculitis, polyarthritis and osteomyelitis associated with pancreatic neoplasia in two dogs., J Small Anim Pract 47 (7) pp. 400-404
A 12-year-old crossbred dog (case 1) and a 12-year-old Shetland sheepdog (case 2) were presented with a history of lameness and distal limb swelling. Physical examination revealed joint effusions and asymmetrical swellings of the extremities. In case 1, a diagnosis of arthritis and cellulitis was made on fine-needle aspiration biopsy of the synovium and subcutis. In case 2, bone biopsies and synovial aspirates diagnosed osteomyelitis and arthritis. A diagnosis of pancreatic disease was made on the findings of marked elevations of serum lipase concentrations and ultrasonographic identification of pancreatic masses in both cases. Both the cases were non-responsive to symptomatic management and were subsequently euthanased. Postmortem examination confirmed the diagnosis of panniculitis, arthritis and osteomyelitis in both cases. A pancreatic exocrine adenoma was identified in case 1 and a pancreatic adenocarcinoma with widespread metastases in case 2. To the authors' knowledge the association of panniculitis, polyarthritis and osteomyelitis with pancreatic disorders has not been reported previously in canine clinical cases.
Day MJ, Henderson SM, Belshaw Z, Bacon NJ (2004) An immunohistochemical investigation of 18 cases of feline nasal lympoma, Journal of Comparative Pathology 130 (2-3) pp. 152-161
This report details clinical, histopathological and immunohistochemical findings in 18 cats with chronic nasal disease diagnosed as nasal lymphoma. Eight of the cats were female and 10 were male, with a median age of 10.5 years (range 7-14 years). Three of the cats were Siamese, one was Burmese, and the rest were non-pedigree. The duration of clinical signs before referral ranged from 30 to 540 days (median 88.5 days). The most common clinical signs were nasal discharge, stertor and sneezing. Nasal radiographs were abnormal in 14/16 cases examined. Abnormal masses were detected endoscopically in 13/18 cases. Nine cats received multi-agent chemotherapy or radiation therapy, or both, with survival times ranging from 14 to > 541 days. Biopsy material from these 18 cats was examined by light microscopy, and serial sections were subjected to immunohistochemical labelling for the T lymphocyte marker CD3 and the B lymphocyte marker CD79a. In 13 tissues, expression of class II molecules of the major histocompatibility complex and the myelomonocytic antigen MAC387 was also determined. Twelve of the tumours were classified as diffuse large B-cell lymphomas, four as lymphoblastic B-cell lymphomas, and one as a follicular B-cell lymphoma. The tumour cells within these lesions all expressed CD79a, and (where tested) most also expressed MHC class II. One tumour was an anaplastic large cell neoplasm, in which the neoplastic cells expressed MHC class II alone in the absence of either lymphoid marker. There was a variable infiltration of reactive small T lymphocytes into these tumours, and zones of necrosis within the tumour tissue were sometimes heavily infiltrated by MAC387 + phagocytic cells. © 2003 Elsevier Ltd. All rights reserved.
Guérios SD, Silva DM, Souza CH, Bacon NJ (2015) Surgical placement and management of jugular vascular access ports in dogs and cats: Description of technique<sup>¤</sup>, Revista Colombiana de Ciencias Pecuarias 28 (3) pp. 165-171
© 2015, Universidad de Antioquia. All rights reserved.Background: vascular access ports (VAPs) are designed to allow repeated access to the vascular system with minimum patient distress. Objective: to describe the surgical technique, care and complications of jugular VAPs currently used at the Veterinary Oncology Service of the University of Florida Small Animal Hospital. Conclusion: the VAPs can remain in site for long terms (months) with minimum complications, and its placement is a reliable technique that should be considered by veterinarians, particularly for a long-term treatment.
Coomer AR, Bacon N (2009) Primary anastomosis of segmental external auditory canal atresia in a cat., J Feline Med Surg 11 (10) pp. 864-868
External auditory canal atresia (EACA) may arise as a congenital deformity, or as sequel to external auditory canal trauma. Diagnosis of EACA was made in this 3-year-old cat by video otoscopy and computed tomography. Successful treatment of congenital segmental EACA was achieved, using end-to-end anastomosis. Primary anastomosis should be considered for treatment of both acute and chronic separation of the annular and auricular cartilages, as well as congenital EACA in the cat.
Belshaw Z, Bacon NJ, Foale RD, Mannion PM, Reuter R (2005) Pancreatic mixed acinar-endocrine carcinoma in a dog., Vet Comp Oncol 3 (3) pp. 145-148
A 10.5-year-old crossbreed dog was presented with a history of hypoglycaemic episodes and elevated serum insulin concentration. A pancreatic mass was removed at surgery along with an enlarged draining lymph node. An unresectable hepatic nodule was also present. Immunohistochemistry confirmed the pancreatic and lymph node masses as functional mixed acinar-endocrine carcinoma, previously unreported in domestic species. Persistent hypoglycaemia and hyperinsulinaemia post-operatively was highly suggestive of the hepatic mass being a functional metastasis. The dog was managed on prednisolone and remained asymptomatic 9 months post-operatively. This tumour type has only been rarely reported in human patients and may highlight the need for more rigorous immunohistochemical staining of pancreatic masses in veterinary species to identify the prevalence of this tumour type.
Kirkby KA, Wheeler JL, Farese JP, Ellison GW, Bacon NJ, Sereda CW, Lewis DD (2010) Vacuum-assisted wound closure: Clinical applications, Compendium: Continuing Education For Veterinarians 32 (3)
Vacuum-assisted closure (VAC) is a wound management system that exposes a wound bed to local negative pressure to promote healing. Benefits of VAC therapy include removal of fluid from the extravascular space, improved circulation, enhanced granulation tissue formation, and increased bacterial clearance. VAC therapy has been used extensively in human patients to treat a variety of acute and chronic wound conditions. This article reviews the use of VAC therapy in a variety of wound conditions and describes our experiences with using VAC therapy in dogs and cats at the University of Florida. © Copyright 2010 MediMedia Animal Health.
Kishi EN, Holmes SP, Abbott JR, Bacon NJ (2014) Functional metastatic parathyroid adenocarcinoma in a dog,CANADIAN VETERINARY JOURNAL-REVUE VETERINAIRE CANADIENNE 55 (4) pp. 383-388 CANADIAN VET MED ASSOC
A 12-year-old dachshund dog was presented for persistent hypercalcemia and hyperparathyroidism despite bilateral parathyroidectomy. Magnetic resonance imaging of the head, neck, and cranial mediastinum identified an increased number of cranial mediastinal lymph nodes with heterogeneous signal intensity. Hypercalcemia and hyperparathyroidism resolved after surgery to remove multiple cranial mediastinal lymph nodes, one of which contained presumed metastatic parathyroid tissue.
Farese JP, Bacon NJ, Ehrhart NP, Bush J, Ehrhart EJ, Withrow SJ (2008) Oesophageal leiomyosarcoma in dogs: surgical management and clinical outcome of four cases., Vet Comp Oncol 6 (1) pp. 31-38
Oesophageal leiomyosarcoma has yet to be reported in dogs. This retrospective case series describes the case management and clinical outcome of four dogs with oesophageal leiomyosarcoma treated by marginal excision alone. Histological features used to determine tumour grade included capsular invasion, percent necrosis, pleomorphism and mitotic rate. All tumours were designated grade 1 leiomyosarcoma. Excision of all grossly evident tumour tissue was achieved in two of the four cases; however, histopathologic evaluation showed tumour cells at the surgical margins in one of these two cases. Two dogs had grossly incomplete excision. Two dogs died from unrelated conditions, one 3 years and 5.5 months after surgery, the other at 65 days. One dog had persistent mega-oesophagus and was lost to follow-up 388 days after surgery and one dog is still alive (last follow-up 405 days after surgery). Despite large tumour size and incomplete excision, surgical removal of low-grade leiomyosarcomas can result in long-term resolution of clinical signs.
Villedieu Erika J., Petite Audrey, Godolphin Janet, Bacon Nick (2020) Prevalence of pulmonary nodules suggestive of metastasis at presentation in dogs referred for treatment of cutaneous and subcutaneous soft tissue sarcomas: 146 cases (2014-2018).,JAVMA-JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION AMER VETERINARY MEDICAL ASSOC
Objective: The aim of this study was to investigate the prevalence of pulmonary nodules at presentation in cases of soft tissue sarcoma (STS) in dogs with no previous thoracic imaging.
Animals: Client-owned dogs with a histologic diagnosis of STS.
Procedures: Dogs were retrospectively included in this study if the first thoracic imaging performed was at the time of presentation to our referral center. De novo and recurrent tumors were included, and information regarding tumor grade, history (primary mass vs scar vs recurrence), duration, location and size was also collected.
Results: One hundred and forty-six dogs were included. Routine staging was performed with computed tomography (131 dogs, 89.7%) or 3-view thoracic radiographs (15 dogs, 10.3%). STS were grade 1 in 55.5% of dogs, grade 2 in 27.4% and grade 3 in 17.1%. Pulmonary nodules suggestive of metastasis were present in 11.7% of cases overall and in 6.5%, 5.6% and 37.5% of grade 1, grade 2 and grade 3 STS cases, respectively. Tumor grade (low/intermediate versus high) and tumor duration ( 3 months) were significantly associated with presence of pulmonary nodules at presentation.
Conclusions and Clinical Relevance: This is the first large study reporting prevalence of pulmonary nodules at presentation in dogs with STS having had no previous thoracic imaging. The prevalence of pulmonary nodules suggestive of metastasis at presentation is low (