Equine cheek tooth extraction: Comparison of outcomes for five extraction methods.

BACKGROUND: Post-operative complications are reported for all methods of equine cheek tooth extraction but not all methods carry the same risks. An outcome comparison for commonly used methods is needed so that clinicians can make informed treatment decisions. OBJECTIVES: We conducted a side-by-side comparison of five cheek tooth extraction methods, comparing types and incidence of complications among oral extraction, tooth repulsion (three surgical approaches) and lateral buccotomy techniques. STUDY DESIGN: Retrospective clinical study using hospital medical records. METHODS: Medical records of all horses undergoing cheek tooth extraction between 1997 and 2013 were reviewed. Logistic regression was used to determine the likelihood of various post-operative complications, comparing oral extraction, tooth repulsion by maxillary and mandibular trephination or maxillary sinus bone flap, and lateral buccotomy. RESULTS: The study included 137 horses and 162 cheek teeth extractions. Oral extraction was successful in 71% of patients in which it was attempted. Oral extraction (n = 55) had the lowest incidence of complications (20%) and repulsion by sinus bone flap (n = 20) the highest (80%). Complication rates for repulsion by maxillary (n = 19) and mandibular trephination (n = 28), and extraction by lateral buccotomy (n = 15) were 42, 54 and 53%, respectively. Cheek tooth repulsion by sinus bone flap significantly increased the odds of damage to adjacent teeth, post-operative sinusitis, damage to alveolar bone, delayed alveolar granulation and orosinus fistulation. Repulsion by maxillary trephination significantly increased the odds of superficial incisional surgical site infection; and extraction by lateral buccotomy significantly increased the odds of facial nerve neuropraxia. Post-operative pyrexia was more common in all repulsion methods. MAIN LIMITATIONS: Some clinically relevant differences may have been missed due to small group numbers in several categories. CONCLUSIONS: Oral extraction was associated with fewer post-operative complications than any other methods. Standing oral extraction remains the preferred choice, and recent surgical advances promise to further improve its success rate.

A comparison of seven methods for continuous therapeutic cooling of the equine digit.

REASONS FOR PERFORMING STUDY: Digital hypothermia may be effective for laminitis prophylaxis and therapy, but the efficacy of cooling methods used in clinical practice requires evaluation. OBJECTIVES: To use hoof wall surface temperature (HWST) to compare several cooling methods used in clinical practice. STUDY DESIGN: Experimental crossover design with a minimum washout period of 72 h. METHODS: Seven cooling methods (commercially available ice packs, wraps and boots) and one prototypical dry-sleeve device were applied to a single forelimb in 4 horses for 8 h, during which HWST of the cooled forelimb and the uncooled (control) forelimb was recorded hourly. Results were analysed descriptively. RESULTS: The median (range) HWST from 2-8 h was lowest for the ice and water immersion methods that included the foot and extended proximally to at least include the pastern: 5.2°C (range: 4.8-7.8°C) for the fluid bag and 2.7°C (2.4-3.4°C) for the ice boot. An ice boot that included the distal limb but not the foot resulted in a median HWST of 25.7°C (20.6-27.2°C). Dry interface applications (ice packs) confined to the foot only resulted in a median HWST of 21.5°C (19.5-25.5°C) for the coronet sleeve and 19.8°C (17.6-23°C) for a commercial ice pack. For the dry interface applications that included the foot and distal limb, the median HWST was much higher for the ice pack device, 19.9°C (18.7-23.1°C), compared with the perfused cuff prototype of 5.4°C (4.2-7°C). CONCLUSIONS: Immersion of the foot and at least the pastern region in ice and water achieved sustained HWST <10°C as did a prototype perfused cuff device with a dry interface. Variation between cooling methods may have a profound effect on HWST and therefore efficacy in clinical cases where laminitis prophylaxis or therapy is the goal.

Clinical treatment and prognosis of equine odontoclastic tooth resorption and hypercementosis.

REASONS FOR PERFORMING STUDY: Equine odontoclastic tooth resorption and hypercementosis is an infrequent and underdiagnosed form of severe dental disease in horses that can affect quality of life. The study was performed to compare the clinical, radiographic, histological and prognostic findings specific to equine odontoclastic tooth resorption and hypercementosis in horses. Removal of affected teeth is currently the best treatment. OBJECTIVES: The goals are to report salient clinical and histological features of the disease and its management in a case series describing an under-reported syndrome in horses and the long-term prognosis. STUDY DESIGN: Retrospective case series. METHODS: Medical records from New Bolton Center, University of Pennsylvania from January 2000 to December 2012 were reviewed from horses that had a diagnosis of 'cementoma' or 'hypercementosis' and any associated dental-related diagnosis affecting the teeth and oral cavity. Radiographic, surgical and histological reports were collated and the clinical cases compared and tabulated to provide a better description of the equine disease. RESULTS: A total of 18 cases were identified, 17 of which were geldings and one of which was a nonbreeding stallion; no mares had the disease. The mean age at diagnosis was 24 years, with a range of 17-29 years. There was no breed predilection, and varied clinical signs relating to the mouth were found. Some teeth involved had only radiographic changes of disease and not gross clinical evidence. The mandibular incisors were generally affected earlier than the maxillary incisors, but the disease is progressive, and eventually, all of the incisors and sometimes the canines are involved. No premolars or molars were affected in this case series. CONCLUSIONS: Based on this case series, all teeth, and particularly the incisors, should be examined for signs of gingivitis and hypercementosis and subsequently radiographed for an early diagnosis and management. When compared with our hospital population, older geldings were more likely to be affected with cementoma formation and its accompanying resorptive process. Removal of clinically and radiographically affected teeth carries a good prognosis for improved quality of life.

Evaluation of three techniques to demonstrate retrograde transport of horseradish peroxidase.

Three methods of tracing neural connections by the use of horseradish peroxidase (HRP) were evaluated: (1) endoneurium injection, (2) injection followed by crushing at site of injection, and (3) nerve transection followed by capping of the proximal stump with a silicone cylinder containing HRP. The capping technique resulted in increased uptake and more uniform distribution of HRP in the nerves under study.

Modified carotid artery transposition for repetitive arterial blood gas sampling in large animals.

A modified surgical procedure for creation of a carotid loop for repeated percutaneous sampling of arterial blood gas was performed on 8 Holstein heifers and 14 horses. This approach permitted sampling of blood gas via fine-needle aspiration (one to three times daily) and/or catheterization for extended periods. It offers several advantages over previously reported techniques, including greater accessibility, absence of postoperative complications such as hematoma formation, and absence of foreign materials supporting the loop.

Vascular endothelial growth factor in porcine coronary arteries following balloon angioplasty.

The present study was a preliminary inquiry into the presence of vascular endothelial growth factor (VEGF) in a model of coronary artery response to injury. We examined domestic pigs who had received a diet enriched in saturated fat and cholesterol and undergone balloon angioplasty of one or more coronary arteries. Immunohistochemical analysis of the coronary arteries 2 months after injury revealed the presence of VEGF distributed throughout the media and neointima of the angioplasty lesions and in association with blood vessels in the adventitia and those vessels growing into the base of the neointima. VEGF was also detected in areas of dietary-induced intimal proliferation. This study provided the first immunochemical demonstration of VEGF occuring naturally in a pig model of coronary response to injury.

Influence of dystocia on white blood cell and blood neutrophil counts in mares.

A retrospective study was done on total white blood cell (WBC) and blood neutrophil counts of 41 mares referred to one of two veterinary hospitals for correction of dystocia. The mares were 2 to 19 years of age and included draft, light, and pony breeds. The WBC and neutrophil counts were performed at varying intervals from time of admission to 10 d after delivery of the feti. Retrospective analyses of WBC and neutrophil counts from 10 normal foaling mares from two Pennsylvania breeding farms (Thoroughbred and Trakehner) and from 14 normal foaling pony mares were done as controls. Mean WBC (10446 +/- 2296 cells/mul) and neutrophil (6850 +/- 2136 cells/mul) counts on the day of delivery in mares with normal parturition were slightly elevated over values reported as normal in the literature. The mean blood cell counts gradually declined to 6124 +/- 1255 WBC/mul and 3692 +/- 409 neutrophils/mul on Day 2 postpartum and returned to normal baseline values by Day 3 postpartum (8868 +/- 2693 WBC/mul, 4298 +/- 1966 neutrophils/mul). No toxic neutrophils were present in mares with normal delivery. Mean WBC (11346 +/- 3298 cells/mul) was elevated on the day of delivery in mares with dystocia as a result of neutrophilia with a left shift (9297 +/- 3298 neutrophils/mul). An apparently faster decline occurred in WBC and neutrophil counts of mares with dystocia than in mares with normal delivery, until a marked leukopenia (3905 +/- 1292 WBC/mul) and neutropenia (1570 +/- 1340 neutrophils/mul) occurred on Day 3 postpartum. The leukopenia and neutropenia persisted until Day 5 postpartum. Toxic neutrophils were present in several mares with dystocia.

Effects of a histamine type 2 receptor antagonist, BMY-26539-01, on equine gastric acid secretion.

A dose-response study was undertaken of the effects of a newly developed histamine type 2 receptor antagonist, BMY-26539-01, on gastric acid secretion in 4 fasted horses. Doses of 0.1 mg/kg, 0.3 mg/kg, 0.5 mg/kg, or placebo were administered in a randomly assigned treatment sequence. Hydrogen ion concentration and pH were variable during baseline measurements in all 4 animals; however, following BMY-26539-01 administration, mean pH increased and hydrogen ion concentration decreased in a dose-related pattern. At the 0.3 mg/kg and 0.5 mg/kg dose levels, pH remained elevated for > 4 h and > 8 h, respectively. No adverse effects were observed. A significant level of 0.01 was used for all statistical methods.

Effects of a histamine type-2 receptor antagonist (BMY-25368) on gastric secretion in horses.

The effects of a potent new histamine-2 (H2) receptor antagonist, BMY-25368, were studied on gastric acid secretion in 5 foals from which food was withheld. Doses of 0.02, 0.11, 0.22, and 1.10 mg/kg of body weight were administered IM in a randomly assigned treatment sequence. Following BMY-25368 administration, hydrogen ion concentration was decreased and mean pH was higher than baseline values in a dose-response pattern. At the 0.22 and 1.10 mg/kg doses, the high pH was sustained for greater than 4 hours. The BMY-25368 thus may be useful for treating gastric ulcer disease in horses.

Prognostic index for acute abdominal crisis (colic) in horses.

Selected physical and laboratory findings in 29 horses with acute abdominal crisis were evaluated retrospectively with a logistic regression equation to predict survival or death. Of 17 variables examined, 2 were found to have good predictive correlation. Serum lactate and packed cell volume had a combined predictive value of 94%. Packed cell volume mean values of 43 and 50%, respectively, differentiated survival from death. Serum lactate values of 28.18 mg/dl and 51.28 mg/dl differentiated survival and death. Analysis of data from a previous study of 36 horses with the logistic regression equation predicted survival rate of 96% accuracy, further substantiating the statistical model.

Resistance to gentamicin and amikacin of gram-negative organisms isolated from horses.

Resistance of gram-negative bacteria to gentamicin has become an increasingly common problem among clinical isolates from human beings. Susceptibility of isolates from horses to gentamicin and amikacin was evaluated for the period from July, 1983 to June, 1985. All isolates of Escherichia coli, and species of Enterobacter, Klebsiella, Proteus, and Pseudomonas examined were susceptible to amikacin, except 2 of the 46 Pseudomonas isolates. In contrast, 13 to 50% of isolates were resistant to gentamicin. Escherichia coli, and Klebsiella, Proteus, and Enterobacter species isolates were highly significantly more susceptible to amikacin (P less than 0.01) than to gentamicin. Pseudomonas spp (P = 0.13) were not significantly different in susceptibility to the 2 drugs. There was significant variation among genera in their susceptibility to gentamicin (P = 0.002), primarily because of the frequency of resistance in isolates of Klebsiella spp and Proteus spp, compared with the other 3 organisms (E coli, Enterobacter spp, and Pseudomonas spp). There was no significant difference of susceptibility to amikacin among the genera studied (P = 0.06).

Acid-base and electrolyte balance in dairy heifers fed forage and concentrate rations: effects of sodium bicarbonate.

Eight Holstein heifers were fed diets of alfalfa hay, corn silage, or finely ground corn grain with or without NaHCO3 in a rotating experimental design. Acid-base status and renal excretion of electrolytes were evaluated during short-term (1 and 5 day) and long-term (24 day) feeding trials. Heifers fed alfalfa hay had a greater metabolic buffering capacity than did heifers fed corn silage. Heifers fed grain had lower blood pH and bicarbonate values than did those fed the forage diets. The most pronounced effects of grain-feeding were aciduria and phosphaturia. Aciduria did not occur when NaHCO3 was added to the grain at 2% of the ration on a dry matter basis. Grain-fed heifers had significantly (P less than 0.05) lower blood and urine pH and bicarbonate values, and excreted significantly more calcium, phosphorus, and magnesium in the urine than did those fed grain plus NaHCO3. Sodium bicarbonate, as a 2% dietary supplement, counteracted many effects of high-grain diets.

Comparison of clinical judgment, Doppler ultrasound, and fluorescein fluorescence as methods for predicting intestinal viability in the pony.

Strangulation obstruction was induced in anesthetized ponies for periods of 2 and 3 hours by clamping 45-cm segments of jejunum and associated veins (venous strangulation obstruction) and arteries and veins (arterial and venous strangulation obstruction). Four segments were studied in each of 7 ponies allowed to survive 12 hours, 2 segments in a pony that was allowed to survive 1 hour, and 1 segment in each of 10 ponies allowed to survive 42 days after the strangulation periods ended. Fifteen minutes after the periods of strangulation obstruction ended, the viability of test segments was assessed by clinical judgment (40 segments), fluorescein fluorescence (40 segments), and Doppler ultrasound (32 segments). Because the test segments were normal at necropsy in long-term survivors, all segments were designated as viable. The overall accuracy of the methods used to predict viability was 88% for Doppler ultrasound and 53% each for clinical judgment and fluorescein fluorescence (P less than 0.005). Failures in the last 2 techniques could be attributed to their tendency to score venous strangulation obstruction segments as nonviable (90% for each). Doppler ultrasound was 94% accurate in these segments.

Early mucosal healing and chronic changes in pony jejunum after various types of strangulation obstruction.

Strangulation obstruction was induced in anesthetized ponies for periods of 2 and 3 hours by clamping 45-cm segments of jejunum and their veins only (venous strangulation obstruction, VSO) and arteries and veins (arterial and venous strangulation obstruction, AVSO). These types of strangulation obstruction were studied in 4 segments in each of 4 ponies allowed to survive 12 hours (group 1) and in a single segment in each of 10 ponies allowed to survive 42 days (group 2) after the strangulation period ended. On visual inspection, segments subjected to VSO had hemorrhage and edema in the bowel wall and mesentery and were dark purple after all time intervals. They improved slowly after clamps were removed, but remained hemorrhagic and edematous. Segments subjected to AVSO were purple and had mild edema and scattered petechiae in the bowel wall and mesentery. They improved rapidly and closely resembled normal bowel after 5 minutes of reperfusion. On light and scanning electron microscopy, the mucosa of intestine subjected to VSO and AVSO had necrotic, denuded villi 1 hour after the strangulation periods ended. Twelve hours after removal of occlusion devices in group-1 ponies, 4 (25%) segments were unchanged, 4 (25%) had deteriorated, and 8 (50%) had stunted villus remnants partly or completely lined with regenerating epithelium. Separation and detachment of villus tip mucosal cells were seen in 3 of 4 control segments, 1 and 12 hours after the strangulation periods ended.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of a severely comminuted fracture of the third metacarpal bone in a horse.

A 4-year-old Standardbred stallion sustained a severely comminuted fracture involving the second, third, and fourth metacarpal bones. The fracture was repaired using two 14-hole broad dynamic compression plates positioned at 90 degrees to one another, allowing one plate to protect the other in the bending mode. An autologous cancellous bone graft obtained from the tuber coxae was added at the site of the defect in the mid- to upper third of the third metacarpal bone. Complications associated with the fixation included a Staphylococcus aureus infection 5 months after surgery, laminitis that developed in the opposite forelimb 6 months after the fracture, and septic tenosynovitis in the contralateral hind limb. The septic tenosynovitis prolonged hospitalization for a total of 20 months. Both postoperative problems resolved when the stallion returned to breeding use.

Esophageal duplication cyst as a cause of choke in the horse.

A mare was examined for episodic choking and an abscess in the perilaryngeal region. One month before referral, the mass progressively enlarged, causing esophageal choking. An extraluminal compression of the esophagus 90 cm from the external nares was found on endoscopy and contrast radiography. Serosanguinous fluid aspirated from the mass contained keratinized squamous cells and neutrophils, compatible with an esophageal cyst. Surgical exploration was performed, with incomplete surgical excision. The remaining portion of the cyst was marsupialized and treated locally with a 2% inorganic iodine solution. Further episodes of esophageal choke in this horse have not been reported.

Omphalophlebitis and osteomyelitis associated with Klebsiella septicemia in a premature foal.

Gram-negative neonatal septicemia was diagnosed in a premature Standardbred colt. Clinical signs included lethargy, weakness, loss of suckle reflex, tachypnea, and injected mucous membranes. Sequelae included pneumonia, omphalophlebitis, septic arthritis, and osteomyelitis. Prepartum maternal uterine infection, premature delivery, abnormal parturition with premature fetal membrane separation, and failure of passive transfer of colostral immunoglobulins increased the foal's risk for developing sepsis. Treatment included administration of moxalactam disodium and cefadroxil. The clinical efficacy of cephalosporin antibiotics in the treatment of gram-negative sepsis is discussed.

Use of gastrotomy to relieve esophageal obstruction in a horse.

Esophageal obstruction of 1 week's duration in a gelding was diagnosed by contrast radiography and esophagoscopy. A food bolus was found at the junction of the caudal thoracic portion of the esophagus and the cardia. A gastrotomy was performed through a cranial abdominal incision and a phytobezoar was manually broken down and removed. The gelding was started on complete pellet food and water on the fifth day after surgery. The horse remained clinically normal more than 1 year after surgery.

Complications of umbilical hernias in horses: 13 cases (1972-1986).

Of 147 horses treated for umbilical hernias over a 13.5-year period, 13 horses (8.8%) developed complications in association with umbilical defects. Six horses had intestinal incarceration; the incarceration was reduced manually in 3 horses before admission, resolved without treatment in 2 others, and was surgically reduced in one. Herniorrhaphy was performed on 4 of the 5 horses in which the incarceration did not require surgical reduction, and the fifth was managed conservatively. A horse with a parietal hernia and a horse with intestinal stragulation were treated surgically; in the latter, the involved intestine was resected. These 8 horses recovered. Three horses developed an umbilical abscess and 2 developed an enterocutaneous fistula through their umbilical hernias. Four of these horses responded well to surgery, but one horse with an enterocutaneous fistula died from electrolyte imbalances and peritonitis after an unsuccessful attempt at simple closure. The results of this study confirmed that complications of umbilical hernias are rare in horses; however, when they do develop, they may be one of various forms, some of which are insidious in onset.

Intestinal carcinoid in a mare: an etiologic consideration for chronic colic in horses.

Intestinal carcinoid, or argentaffinoma, should be an etiologic consideration for horses with chronic colic. A mare was referred with a history of chronic colic. Previously, the signs of colic had subsided in response to impiric treatment, but recent episodes of colic did not. Clinical signs and results of physical examination supported the finding of strangulating obstruction of the small intestine. Exploratory celiotomy revealed internal herniation with simultaneous volvulus of the jejunum and accompanying carcinoid.