Effects of unilateral laser-assisted ventriculocordectomy in horses with laryngeal hemiplegia

REASONS FOR PERFORMING STUDY: Recent studies have evaluated surgical techniques aimed at reducing noise and improving airway function in horses with recurrent laryngeal neuropathy (RLN). These techniques require general anaesthesia and are invasive. A minimally invasive transnasal surgical technique for treatment of RLN that may be employed in the standing, sedated horse would be advantageous. OBJECTIVE: To determine whether unilateral laser-assisted ventriculocordectomy (LVC) improves upper airway function and reduces noise during inhalation in exercising horses with laryngeal hemiplegia (LH). METHODS: Six Standardbred horses were used; respiratory sound and inspiratory transupper airway pressure (Pui) measured before and after induction of LH, and 60, 90 and 120 days after LVC. Inspiratory sound level (SL) and the sound intensities of formants 1, 2 and 3 (Fl, F2 and F3, respectively), were measured using computer-based sound analysis programmes. In addition, upper airway endoscopy was performed at each time interval, at rest and during treadmill exercise. RESULTS: In LH-affected horses, Pui, SL and the sound intensity of F2 and F3 were increased significantly from baseline values. At 60 days after LVC, Pui and SL had returned to baseline, and F2 and F3 values had improved partially compared to LH values. At 90 and 120 days, however, SL increased again to LH levels. CONCLUSIONS: LVC decreases LH-associated airway obstruction by 60 days after surgery, and reduces inspiratory noise but not as effectively as bilateral ventriculocordectomy. POTENTIAL RELEVANCE: LVC may be recommended as a treatment of LH, where reduction of upper airway obstruction and respiratory noise is desired and the owner wishes to avoid risks associated with a laryngotomy incision or general anaesthesia.     

Clinical and clinicopathologic variables in adult horses receiving blood transfusions: 31 cases (1999-2005)

OBJECTIVE: To determine clinical and clinicopathologic abnormalities in horses administered a blood transfusion and evaluate effects of blood transfusion on these variables. DESIGN: Retrospective case series. ANIMALS: 31 adult horses that received > or = 1 blood transfusion. Procedures-Medical records of horses receiving a blood transfusion were reviewed to obtain clinical findings, laboratory test results before and after transfusion, adjunctive treatments, transfusion type and volume, response to transfusion, results of donor-recipient compatibility testing, adverse reactions, and outcome. RESULTS: 31 horses received 44 transfusions for hemorrhagic anemia (HG; n = 18 horses), hemolytic anemia (HL; 8), or anemia attributable to erythropoietic failure (EF; 5). Tachycardia and tachypnea were detected in 31 of 31 (100%) and 22 of 31 (71%) horses, respectively, before transfusion. The PCV and hemoglobin concentration were less than the reference range in 11 of 18 horses with HG, 8 of 8 horses with HL, and 5 of 5 horses with EF. Hyperlactatemia was detected in 16 of 17 recorded values before transfusion. Heart rate, respiratory rate, and PCV improved after transfusion, with differences among the types of anemia. Seventeen (54%) horses were discharged, 9 (29%) were euthanized, and 5 (16%) died of natural causes. Adverse reactions were evident during 7 of 44 (16%) transfusions, varying from urticarial reactions to anaphylactic shock. CONCLUSIONS AND CLINICAL RELEVANCE: Abnormalities in clinical and clinicopathologic variables differed depending on the type of anemia. Colic, cold extremities, signs of depression, lethargy, tachycardia, tachypnea, low PCV, low hemoglobin concentration, and hyperlactatemia were commonly detected before transfusion and resolved after transfusion.     

Retinal detachment in horses: 40 cases (1998-2005)

OBJECTIVE: To determine clinical features, ophthalmic examination findings, etiology, treatment, and outcome of horses diagnosed with retinal detachment (RD). ANIMALS STUDIED: Forty horses, presented to the North Carolina State University and The Ohio State University Veterinary Teaching Hospitals from 1998 to 2005 that were diagnosed with RD. PROCEDURE(S): Horses with documented RD, confirmed either on ophthalmic examination or by ultrasonography, and with a complete medical record were included. Information retrieved from the medical records included signalment, presenting complaint, duration of clinical signs, ophthalmologic examination findings, diagnostics performed, identified cause of the retinal detachment, treatment given, and outcome. RESULTS: Forty horses (46 eyes) were diagnosed with RD. Mean +/- SD duration of clinical signs of ocular disease was 10.5 +/- 14.7 months. Thirty-four horses presented with unilateral involvement, 6 with bilateral, 14 with partial and 32 with complete RD. Ultrasonography was used to make the diagnosis in 26 eyes, while RD was diagnosed on routine ocular examination in 20 eyes. Bullous RD was the only type of RD observed, although small vitreal traction bands were considered secondary to the underlying inflammation or trauma. RD caused by equine recurrent uveitis (ERU) was diagnosed in 27 of 40 (67.5%) horses. Trauma-induced RD involved 10 of the 40 horses (25%). Presenting problems included known ERU (n = 16), acute or progressive vision loss (n = 9), known ocular trauma (n = 6), cataract (n = 6), and a cloudy cornea (n = 3). No horses regained vision after RD despite therapy. Many eyes were enucleated or eviscerated, or the horses were euthanized. Seven eyes with complete RD were noted to be unchanged and comfortable with medical therapy. CONCLUSIONS: The visual prognosis of RD in horses is grave; however, horses with nontraumatic RD (most commonly ERU) may be able to maintain a comfortable but blind globe with anti-inflammatory medical therapy.     

Musculoskeletal Corynebacterium pseudotuberculosis infection in horses: 35 cases (1999-2009)

Objective-To describe the clinical course and outcome in horses in which Corynebacterium pseudotuberculosis infections were associated with musculoskeletal disease and lameness. Design-Retrospective case series. Animals-35 horses. Procedures-Clinical and clinicopathologic data were collected from horses diagnosed with lameness associated with C pseudotuberculosis infection between 1999 and 2009. Results-32 (91.4%) horses had grade 4/5 lameness. Three (8.6%) horses had grade 5/5 lameness. Abscesses were diagnosed by clinical or ultrasonographic examination. Abscesses were located in the axillary or triceps region in 25 (71.4%) horses, the stifle region in 2 (5.7%), and the popliteal lymph node in 1 (2.9%). Diffuse lymphangitis was seen in 4 (11.4%) horses, osteomyelitis in 2 (5.7%) horses, and septic arthritis in 2 (5.7%) horses. Horses commonly had clinicopathologic abnormalities characterized by neutrophilia (96.4%), anemia (67.8%), hypoalbuminemia (66.6%), or hyperfibrinogenemia (42.8%). Treatment included surgical drainage of the abscess in 21 (60%) horses, performed under ultrasonography in 20 horses; anti-inflammatory medications in 34 (97.1 %) horses; and antimicrobials in 30 (85.7%) horses. Conclusions and Clinical Relevance-C pseudotuberculosis infection of the limbs in horses typically results in severe lameness but may have a favorable prognosis. The diagnosis may be challenging, and results of blood work consistent with inflammation are nonspecific, but anemia, hyperglobulinemia, and increased synergistic hemolysis inhibition titers are common. Ultrasonography may localize the lesions and facilitate surgical drainage to alleviate lameness. When C pseudotuberculosis musculoskeletal infection results in osteomyelitis or septic arthritis, the prognosis for survival is poor.     

Lung lobe torsion in dogs: 22 cases (1981-1999)

OBJECTIVE: To identify breed disposition, postoperative complications, and outcome in dogs with lung lobe torsion. DESIGN: Retrospective study. ANIMALS: 22 client-owned dogs. PROCEDURE: Information on signalment; history; clinical findings; results of clinicopathologic testing, diagnostic imaging, and pleural fluid analysis; surgical treatment; intra- and postoperative complications; histologic findings; and outcome were obtained from medical records. RESULTS: All 22 dogs had pleural effusion; dyspnea was the most common reason for examination. Fifteen dogs were large deep-chested breeds; 5 were toy breeds. Afghan Hounds were overrepresented, compared with the hospital population. One dog was euthanatized without treatment; the remaining dogs underwent exploratory thoracotomy and lung lobectomy. Eleven dogs recovered from surgery without complications, but 3 of these later died of thoracic disease. Four dogs survived to discharge but had clinically important complications within 2 months, including chylothorax, mediastinal mesothelioma, gastric dilatation, and a second lung lobe torsion. Six dogs died or were euthanatized within 2 weeks after surgery because of acute respiratory distress syndrome, pneumonia, septic shock, pneumothorax, or chylothorax. Chylothorax was diagnosed in 8 of the 22 dogs, including 4 Afghan Hounds. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that lung lobe torsion is rare in dogs and develops most frequently in large deep-chested dogs, particularly Afghan Hounds. Other predisposing causes were not identified, but an association with chylothorax was evident, especially in Afghan Hounds. Prognosis for dogs with lung lobe torsion was fair to guarded.     

Neodymium:yttrium-aluminum-garnet laser-assisted excision of progressive ethmoid hematomas in horses: 20 cases (1986-1996)

OBJECTIVE: To describe a technique of contact neodymium:yttrium-aluminum-garnet (Nd:YAG) laser-assisted excision of progressive ethmoid hematoma (PEH) in horses, to determine the recurrence rate of clinical signs of PEH in horses with follow-up time of a minimum of 12 months, and to compare this result with reported results achieved by using conventional techniques. DESIGN: Retrospective study. ANIMALS: 21 horses with 26 PEH. PROCEDURE: Medical records of all horses with PEH treated by Nd:YAG laser excision from December 1986 through August 1996 were analyzed. Twenty-one horses underwent unilateral (18 surgeries) or bilateral (14) frontonasal bone flap with excision of the mass, using an Nd:YAG laser. One horse with bilateral PEH underwent a unilateral bone flap twice, 1 year apart. RESULTS: 1 horse died. Four of 20 horses with followup times of 12 months or longer had recurrence of PEH. The PEH recurrence rate was 20% (5/25 PEH). Three of 6 horses with bilateral lesions had recurrence of PEH. Recurrence rate for horses that had bilateral PEH (3/6 horses) was greater than for horses with unilateral PEH (1/14 horses). CLINICAL IMPLICATIONS: Treatment of PEH by Nd:YAG laser excision through a frontonasal bone flap results in a recurrence rate comparable with that reported for conventional techniques. Horses with bilateral lesions are more likely to have a recurrence of PEH.     

Laryngoplasty with ventriculectomy or ventriculocordectomy in 104 draft horses (1992-2000)

OBJECTIVE: To evaluate efficacy and safety of laryngoplasty with vetriculectomy (VE) or ventriculocordectomy (VCE) for treatment of laryngeal hemiplegia (LH) in draft horses. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: One hundred four draft horses used for competitive hitch competitions. METHODS: Medical records and postoperative endoscopy for competitive hitch draft horses diagnosed with left LH and treated with laryngoplasty and VE or VCE between January 1992 and December 2000 were reviewed. Follow-up information was obtained from telephone interviews with owners and trainers, and performance scores of 1 to 3 were assigned in which 1 was defined as a horse that was unable to perform (abnormal respiratory noise with or without exercise intolerance), 2 was able to perform but not for its intended use (exercise tolerant but abnormal respiratory noise), and 3 was performing as expected for its intended use (exercise tolerant, no abnormal respiratory noise). RESULTS: One hundred four horses that had 111 laryngoplasty procedures were included. All horses had preoperative performance scores of 1. Follow-up information was available for 79 horses. Improvement in postoperative performance (exercise tolerant, with or without abnormal respiratory noise) was reported in 92% of horses. Respiratory noise was eliminated in 72% (57 horses) of horses. Postoperative performance scores were the following: 3 in 57 (72%) horses, 2 in 16 (20%) horses, and 1 in 6 (8%) horses. There was no significant difference in postoperative performance based on preoperative grade of LH. There was a trend for horses with >/=70% of possible maximal abduction postoperatively to have a performance score of 3. Postanesthetic complications included prolonged recovery (4 horses, 4%) and myopathy or neuropathy (7 horses, 7%). One of these horses was killed because it did stand; triceps myopathy and encephalopathy were confirmed on necropsy. CONCLUSIONS: Laryngoplasty with VE or VCE is an effective and safe procedure for the treatment of LH in the draft horse. Repeat laryngoplasty can be performed successfully, with good performance outcome after laryngoplasty failure. Complications associated with general anesthesia and laryngoplasty in draft horses are higher than reported for light breed horses under similar conditions. CLINICAL RELEVANCE: For LH, laryngoplasty with VCE or VE under general anesthesia is recommended to eliminate abnormal respiratory noise and improve performance in most competitive hitch draft horses.     

Rupture of collateral ligaments in metacarpophalangeal and metatarsophalangeal joints in horses: 17 cases (1999--2005)

OBJECTIVE: To characterize ruptures of collateral ligaments (CLs) in metacarpophalangeal and metatarsophalangeal joints in horses. DESIGN: Retrospective case series. ANIMALS: 17 horses with ruptured CLs. PROCEDURES: Data were obtained from medical records, including signalment, history, clinical signs, ultrasonographic and radiographic findings, treatment, and outcome. Additional follow-up information was obtained from owners or referring veterinarians. RESULTS: The lateral CL was ruptured in 11 horses; the medial CL was ruptured in 6 horses. Ultrasonography revealed ipsilateral rupture of the short and long components of the CL in 11 horses and rupture of only 1 component in 6 horses. No biaxial ruptures were detected, but 9 horses had desmitis of the CL on the nonruptured side of the affected joint. All horses were lame (lameness score range, 2/5 to 4/5). Joint instability was palpable in 9 horses; only 4 horses had episodes of joint luxation. Avulsion fractures were identified radiographically in 6 horses and ultrasonographically in another 2 horses. Stress radiography revealed joint instability in 10 horses. Horses were managed by stall confinement, limb immobilization, and gradual return to exercise. Eight horses returned to riding, 2 resumed breeding, 2 were retired, 2 were euthanized, and 3 were doing well 86 to 139 days after injury. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonographic examination is indicated in horses with acute lameness and swelling at the metacarpophalangeal or metatarsophalangeal joint, particularly when stress radiography cannot be performed or findings are equivocal. Affected horses can be conservatively managed. Prognosis for athletic use may be better than originally believed.     

Surgical management of gallbladder mucoceles in dogs: 22 cases (1999-2003)

OBJECTIVES: To describe preoperative, surgical, and postoperative findings and determine prognostic indicators and treatment recommendations in dogs treated surgically for gallbladder mucocele. DESIGN: Retrospective study. ANIMALS: 22 client-owned dogs. PROCEDURES: Medical records of dogs with gallbladder mucoceles that were treated surgically were reviewed. History, clinical signs, results of selected clinicopathologic analyses and abdominal ultrasonography, surgical procedure performed, results of histologic examination of a liver biopsy specimen, and survival time were recorded. Follow-up information was obtained via telephone interview with owners and referring veterinarians. RESULTS: Dogs were 7 to 15 years of age and had non-specific clinical signs (vomiting, anorexia, and lethargy). Physical examination findings included icterus, signs of depression, and signs of discomfort on palpation of the abdomen. Sixteen dogs had a definitive diagnosis and 6 dogs were strongly suspected of having a gallbladder mucocele on the basis of results of abdominal ultrasonography. Fifteen dogs survived after surgery; 3 of these dogs had bile-induced peritonitis, and 4 had pancreatitis. One dog was euthanatized as a result of severe pancreatitis, and 1 was euthanatized because of acute renal failure; 5 dogs died as a result of pancreatitis, cholecystitis, or bile-induced peritonitis. Hepatic abnormalities were detected histologically in all dogs. CONCLUSIONS AND CLINICAL RELEVANCE: No predictors of survival were identified. No associations between outcome of surgical treatment (survival vs nonsurvival) and preoperative findings, biliary rupture, surgical procedure performed, results of histologic examination of the liver, or development of pancreatitis were found. Cholecystoduodenostomy and cholecystectomy appear to be acceptable treatments for gallbladder mucocele.     

Nd:YAG laser-assisted modified Forssell's procedure for treatment of cribbing (crib-biting) in horses

OBJECTIVE: To report an neodymium:yttrium-aluminum garnet (Nd:YAG) laser-assisted modified Forssell's surgical technique and outcome for treatment of cribbing (crib-biting) in horses. STUDY DESIGN: Retrospective clinical study. ANIMALS: Ten adult horses with stereotypic cribbing behavior. METHODS: Data were obtained from medical records and telephone conversations with owners, trainers, and veterinarians. Surgical technique involved an approximately 34-cm ventral median skin incision starting rostral to the larynx and extending caudally. A 10-cm section of the ventral branch of the spinal accessory nerve was removed, using an Nd:YAG laser at 25 W and continuous pulse with a contact, sculpted-fiber tip. After neurectomy, approximately 34-cm sections of the paired omohyoideus and sternothyrohyoideus muscles were removed starting 2 cm rostral to the ventral aspect of the larynx, at the basihyoid bone, using the Nd:YAG laser. RESULTS: Median horse age was 7 years (range, 1 to 11 years). Median surgical time was 90 minutes (range, 75 to 130 minutes). Long-term outcome (range, 7 to 72 months) was available for all horses. None of the horses had cribbing behavior after surgery, and all returned to their previous use. Four horses had complications (two of which were unrelated to the surgical site), but all recovered fully. CONCLUSION: The successful outcome we obtained is better than reported previously using a modified Forssell's technique. CLINICAL RELEVANCE: Surgical treatment for cribbing by Nd: YAG laser-assisted myectomy and neurectomy resulted in an excellent prognosis for resolution of the stereotypical behavior with minimal complications.     

Predisposing factors for small colon impaction in horses and outcome of medical and surgical treatment: 44 cases (1999-2004)

OBJECTIVE: To identify factors associated with development of small colon impaction in horses and with selection of medical versus surgical treatment and to determine the prognosis for affected horses following medical or surgical management. DESIGN: Retrospective case series. ANIMALS: 44 horses with primary impaction of the small colon. PROCEDURES: Medical records were reviewed for signalment, history, clinical findings, treatment (medical vs surgical), hospitalization time, and outcome. For comparison purposes, the same information was collected for 83 horses with primary impaction of the large colon. RESULTS: Diarrhea was the only factor found to be associated with development of small colon impaction. Horses with small colon impaction were 10.8 times as likely to have diarrhea at the time of initial examination as were horses with large colon impaction. Abdominal distension was the only factor associated with use of surgical versus medical treatment. Horses with small colon impaction that were treated surgically were 5.2 times as likely to have had abdominal distension at the time of admission as were horses with small colon impaction that were treated medically. Overall, 21 of 23 (91%) horses treated medically and 20 of 21 (95%) horses treated surgically survived to discharge. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that diarrhea may be a risk factor for development of small colon impaction and that horses with small colon impaction that have abdominal distension at the time of initial examination are more likely to require surgical than medical treatment.     

Assessment of the efficacy of an abductor muscle prosthesis for treatment of laryngeal hemiplegia in horses

Four variations of abductor muscle prosthesis for treating laryngeal hemiplegia were evaluated in 153 horses by questionnaire, and in the 100 Thoroughbred racehorses in this group survival analysis was used to compare their racing performances and earnings with those of 400 control horses. The questionnaire indicated that the technique which included a ventriculectomy and 2 prostheses was regarded as being the most successful (P less than 0.01) and resulted in the least residual stertor (P less than 0.001). Survival analysis showed that there was no significant difference between the treated group of horses and the control horses (P greater than 0.05).     

Effects of ventriculectomy, prosthetic laryngoplasty, and exercise on upper airway function in horses with induced left laryngeal hemiplegia

Effects of ventriculectomy and prosthetic laryngoplasty on upper airway flow mechanics and blood gas tensions in exercising horses with induced left laryngeal hemiplegia were assessed. Five adult horses were trained to stand, trot (4.5 m/s), and gallop (7.2 m/s) on a treadmill (6.38 degrees incline). Inspiratory and expiratory airflows (VImax, VEmax, respectively) were measured using a 15.2-cm diameter pneumotachograph in a face mask. Inspiratory and expiratory transupper airway pressures (PuI, PuE, respectively) were determined as pressure differences between barometric pressure and lateral tracheal pressure. Blood collected from exteriorized carotid arteries was analyzed for PaO2, PaCO2, pH, hemoglobin (Hb) content, and HCO3- values. Heart rate (HR) was determined with an HR monitor. Measurements were made with horses standing, trotting, and galloping before left recurrent laryngeal neurectomy (LRLN; base line), 14 days after LRLN, 30 days after ventriculectomy (44 days after LRLN), and 14 days after prosthetic laryngoplasty (58 days after LRLN). Before LRLN (base line), increasing treadmill speed for horses from standing to the trot and gallop progressively increased HR, respiratory frequency, VImax, VEmax, PuI, PuE, Hb, and PaCO2 values and decreased PaO2, pH, and HCO3- values; inspiratory and expiratory impedances were unchanged. After LRLN, inspiratory impedance and PuI were significantly (P less than 0.05) increased in horses at the trot and gallop, and PaCO2 was significantly increased in horses at the gallop. The VImax and respiratory frequency were significantly (P less than 0.05) decreased in horses at the gallop. Left recurrent laryngeal neurectomy had no effect on PuE, VEmax, HR, PaO2, pH, Hb, or expiratory impedance values.(ABSTRACT TRUNCATED AT 250 WORDS)     

Renal tubular acidosis in horses (1980-1999)

Renal tubular acidosis (RTA) is characterized by altered renal tubular function resulting in hyperchloremic metabolic acidosis. The purpose of the study was to describe RTA in 16 horses. No breed or sex predilection was found. The mean age at onset of the disease was 7 years of age. The type of diet had no apparent effect on development of RTA. The most common clinical signs were depression, poor performance, weight loss, and anorexia. Initial blood work revealed a marked hyperchloremic metabolic acidosis in all horses and a compensatory respiratory response in most horses. Sixty-three percent (10/16) of the horses had some evidence of renal damage or disease. Initial treatment consisted of large amounts of sodium bicarbonate given intravenously and orally for the prompt correction of the acidosis. Response to treatment was largely dependent on the rate of sodium bicarbonate administration. Long-term oral supplementation with NaHCO3 was required for the maintenance of normal acid-base status in individual horses. Recurrence of RTA was noted in 56% (9/16) of the horses. Horses with evidence of renal disease had multiple relapses. RTA should be considered as a differential diagnosis in horses with vague signs of depression, weight loss, and anorexia. The pathogenesis of RTA in horses remains uncertain, but prompt recognition and early aggressive intravenous sodium bicarbonate therapy followed by long-term oral supplementation seem to be important to successful management.     

Analysis of risk factors for recurrent airway obstruction in North American horses: 1,444 cases (1990-1999)

OBJECTIVE: To identify risk factors for recurrent airway obstruction (RAO) among horses examined at veterinary teaching hospitals in North America. DESIGN: Retrospective case-control study. ANIMALS: 1,444 horses with RAO and 1,444 control horses examined for other reasons. PROCEDURE: The Veterinary Medical Database was searched for records of horses in which RAO was diagnosed. A control group was identified by randomly selecting a horse with a diagnosis other than RAO that matched the institution and year of admission for each of the horses with RAO. Information obtained included hospital, admission year and month, age, sex, breed, and discharge status. The association between risk factors and diagnosis of RAO was estimated with logistic regression models. RESULTS: The risk of RAO increased significantly with age, with horses > or = 7 years old being 6 to 7 times as likely to have RAO as were horses < or = 4 years old. Thoroughbreds were 3 times as likely to have RAO as were ponies. Horses were 1.6 and 1.5 times as likely to be examined because of RAO during winter and spring, respectively, than they were during summer. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that RAO was more likely to be diagnosed in females, horses > or = 4 years old, and Thoroughbreds and that RAO has a seasonal distribution.     

Use of magnetic resonance imaging for identifying subchondral bone damage in horses: 11 cases (1999-2003)

OBJECTIVE: To assess the use of magnetic resonance (MR) imaging for identifying subchondral bone damage in the distal limbs of horses. DESIGN: Retrospective study. ANIMALS: 11 horses. PROCEDURE: Medical records of horses with lameness and subsequent evidence of subchondral bone damage as determined by MR imaging were reviewed. Severity and duration of lameness, results of diagnostic local anesthesia and diagnostic testing, surgical and necropsy findings, and treatment were recorded. Outcome was determined by follow-up information obtained from the owner or referring veterinarian. RESULTS: Lameness was localized by physical examination and diagnostic local anesthesia. Lameness was localized to the metacarpophalangeal or metatarsophalangeal joint in 4 horses, distal interphalangeal joint in 5 horses, and tarsocrural joint in 2 horses. The duration of lameness ranged from 2 weeks to 20 months. Magnetic resonance imaging of the affected joints revealed abnormal fluid accumulation within the subchondral bone. None of the abnormalities observed by MR imaging were detected by radiography. Subchondral bone damage was diagnosed in all horses. Arthroscopy of the affected joint was performed in 4 horses. Communication with the articular surface of the affected bone was suspected on the basis of results of MR imaging in 4 horses and was confirmed by arthroscopy in 1 horse and by necropsy in 1 horse. CONCLUSIONS AND CLINICAL RELEVANCE: Magnetic resonance imaging was useful for providing a diagnosis when other imaging techniques did not definitively identify the cause of lameness. Subchondral bone damage was clearly identified by MR imaging and should be considered as a cause of lameness in horses in which radiographic findings are unremarkable.     

Minimally invasive plate fixation of lower limb injury in horses: 32 cases (1999-2003)

REASONS FOR PERFORMING STUDY: Complications of osteosynthesis including superficial and deep infections continue to affect adversely outcome in equine surgery of the lower limb. OBJECTIVE: To describe a technique for minimally invasive plate fixation in horses and evaluate clinical results of the technique. HYPOTHESIS: Lower complication rates would occur in horses treated with a minimally invasive approach compared with conventional techniques. METHODS: Cases of minimally invasive plate fixation from January 1999 to December 2003 were evaluated. Case records, radiographs and race records for horses that sustained distal third metacarpal/metatarsal (Mc/tIII) condylar fractures were assessed. Follow-up information was obtained and results analysed. In addition, results for horses that received arthrodesis by a conventional, open approach during the same period were evaluated and statistical analysis was performed. RESULTS: Thirty-two cases of minimally invasive plate fixation were identified (22 incomplete distal Mc/tIII condylar fractures with a spiralling or diaphyseal component, 10 metacarpophalangeal arthrodeses and 4 pastern arthrodeses). For both types of arthrodesis, surgery times and infection rates were lower and survival rates higher in the minimally invasive group, but no statistical difference was found. Spiralling condylar fractures were successfully managed, without catastrophic fracture. CONCLUSIONS AND POTENTIAL RELEVANCE: Minimally invasive percutaneous plate osteosynthesis (MIPPO) can be successfully used for select applications in horses, and may reduce morbidity and mortality in equine fracture repair.     

Tilt table recovery of horses after orthopedic surgery: fifty-four cases (1994-2005)

OBJECTIVE: To describe an assisted anesthetic recovery technique using a tilt table for horses after high-risk orthopedic-related procedures and to evaluate outcome. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Anesthetic recoveries (n=54) for 36 horses. METHODS: Medical records (April 1994-October 2005) for horses that had high-risk orthopedic surgery and recovery from general anesthesia on a tilt table were reviewed. Information about the surgical procedure, anesthetic and recovery period was analyzed. RESULTS: Of 54 anesthetic recoveries, 1 horse (1.9%) had complete failure of internal fixation during recovery and was euthanatized. Six (11% recoveries) horses failed to adapt to the tilt table system, which necessitated transfer to a conventional recovery room. Complications without important consequences for clinical outcome (skin abrasions, myositis, cast breakage, partial implant failure) occurred during 8 (15%) recoveries. CONCLUSIONS: A tilt table recovery system was associated with minimal incidence of serious complications. Potential disadvantages of the system are the number of personnel required, longer recovery time, and the need for a specialized table. CLINICAL RELEVANCE: A tilt table is a useful system for recovering horses believed to be at increased risk of injury during anesthetic recovery after high-risk orthopedic-related procedures.     

Samarium Sm 153 lexidronam for the palliative treatment of dogs with primary bone tumors: 35 cases (1999-2005)

OBJECTIVE: To evaluate survival times and palliative effects associated with the use of samarium Sm 153 lexidronam in dogs with primary bone tumors. DESIGN: Retrospective case series. ANIMALS: 35 dogs with primary appendicular (n = 32) or axial (3) bone tumors. PROCEDURES: 1 to 4 doses of samarium Sm 153 lexidronam were administered at a rate of 37 MBq/kg (16.8 MBq/lb), IV. Response to treatment, measured by lameness improvement, and survival time were determined. RESULTS: Of the 32 dogs with appendicular tumors, 20 (63%) had an improvement in the severity of lameness 2 weeks after administration of the first dose of radioactive samarium, 8 (25%) had no change in the severity of lameness, and 4 (12%) had a worsening. Overall median survival time was 100 days, with 3 dogs (8.6%) alive after 1 year. Median survival time for the 32 dogs with appendicular tumors was 93 days, with 3 (9.4%) alive after 1 year. This was not significantly different from the median survival time of 134 days for a historical cohort of 162 dogs with appendicular osteosarcoma that underwent amputation as the only treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that samarium Sm 153 lexidronam may be useful in the palliation of pain in dogs with primary bone tumors that are not candidates for curative-intent treatment.