Positron emission tomography assessment of metacarpal/metatarsal condylar fractures post surgical repair: Prospective study in 14 racehorses.

OBJECTIVES: To assess 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) findings associated with metacarpal/metatarsal condylar fractures at the time of fracture repair and through healing. STUDY DESIGN: Prospective descriptive study. ANIMALS: Fourteen Thoroughbred racehorses. METHODS: 18F-NaF PET was performed within 4 days of surgical metacarpal/metatarsal condylar fracture repair, on both the injured and contralateral limb. Follow-up PET scans were offered at 3- and 5-months post fracture repair. Areas of abnormal uptake were assessed using a previously validated grading system. RESULTS: Eight fractures were located in the parasagittal groove (PSG) (six lateral and two medial) and six fractures were located abaxial to the PSG (non-PSG) through the palmar/plantar condyle (all lateral). All horses in the latter group had uptake in the lateral palmar condyle of the contralateral limb suggestive of stress remodeling. Three horses with PSG fractures had uptake in a similar location in the contralateral limb. Horses with lateral condylar fracture only presented minimal or mild uptake in the medial condyle, which is considered atypical in the front limbs for horses in full training. Four horses developed periarticular uptake in the postoperative period suggestive of degenerative joint disease, three of these horses had persistent uptake at the fracture site. These four horses did not return to racing successfully. CONCLUSION: The findings of this study provide evidence of pre-existing lesions and specific uptake patterns in racehorses suffering from metacarpal/metatarsal condylar fractures. CLINICAL SIGNIFICANCE: PET has a possible role in the prevention, diagnosis, and postoperative monitoring of metacarpal/metatarsal condylar fractures in racehorses.

Assessment and comparison of microcirculation and macrocirculation in horses undergoing emergency exploratory celiotomy versus elective surgical procedures.

OBJECTIVE: To assess oral buccal microcirculation by hand-held videomicroscopy in horses during colic surgery, comparing microcirculation values with macrocirculatory parameters and with those of healthy elective surgical horses. STUDY DESIGN: Clinical prospective study. ANIMALS: Client-owned horses (nine in the colic group; 11 in the elective group). METHODS: In the colic group, buccal mucosal side stream dark-field microscopy (DFM) videos, cardiac output (CO), mean arterial pressure (MAP), and lactate were obtained at three timepoints under general anesthesia (30, 90, and 150 min after induction). Video analysis was used to determine total vessel density, proportion of perfused vessels, perfused vessel density, and heterogeneity index. Dark-field microscopy videos, MAP, and lactate were obtained at a single timepoint under general anesthesia (45 min after induction) in the elective group. RESULTS: There were no differences in microcirculatory parameters between colic and elective horses, nor was there a difference across timepoints in the colic group. There was a weak negative correlation between microvascular parameters and CO (rho = -0.23). CONCLUSION: The colic group did not have decreased microcirculation in comparison with the healthy elective group. Dark-field microscopy did not correlate well with macrocirculatory parameters in the colic group. IMPACT: Dark-field microscopy may not be a sensitive enough indicator to detect differences in microcirculation between colic and elective groups. The lack of difference in microcirculation may be due to sample size, probe location, or variation in disease severity.

Computed tomographic assessment of fracture characteristics and subchondral bone injury in Thoroughbred racehorses with lateral condylar fractures and their relationship to outcome.

OBJECTIVE: To investigate the effects of fracture characteristics and concurrent subchondral bone pathology identified with computed tomography (CT) on the racing performance of Thoroughbred racehorses with fractures of the MC3/MT3 lateral condyle. STUDY DESIGN: Retrospective cohort study. SAMPLE POPULATION: Thoroughbred racehorses (n = 50) with a fracture of the MC3/MT3 lateral condyle, which had preoperative CT and internal fixation performed. METHODS: Medical records were reviewed for age, sex, limb, and surgical treatment. Computed tomography scans were evaluated to determine fracture characteristics including length, whether the fracture was incomplete or complete, and displacement. The presence of subchondral bone injury (SBI), sesamoid bone fracture, articular comminution, and fragmentation in the joint was noted. Racing data was obtained from an online database. Univariable and multivariable analyses determined associations between independent variables and outcomes. RESULTS: Thirty-three (66%) horses raced after surgery. Horses with sesamoid bone fractures (P = .021), MC3/MT3 comminution (P = .016) and intra-articular fragmentation (P = .015) were less likely to race postoperatively. Concurrent SBI did not affect outcome. In the final multivariable model, sex (P = .015) and whether a fracture was incomplete or complete (P = .007) were the most significant predictors of racing postoperatively with females and horses with complete fractures being less likely to race. CONCLUSION: The prognosis for racing after a lateral condylar fracture is favorable but is decreased in horses with complete fractures and certain concurrent joint pathology. CLINICAL SIGNIFICANCE: Horses presenting with lateral condylar fractures commonly have concurrent joint pathology. Computed tomography can aid in preoperative evaluation and prognostication by enabling more complete fracture assessment.

Suspensory ligament size does not change after plantar fasciotomy and neurectomy of the deep branch of the lateral plantar nerve by ultrasonographic assessment.

OBJECTIVE: To determine the short-term effect of plantar fasciotomy and neurectomy (PFN) of the deep branch of the lateral plantar nerve on the proximal suspensory ligament (PSL) cross-sectional area (CSA) in horses with hindlimb proximal suspensory desmopathy (PSD). STUDY DESIGN: Analytical, observational, cohort study. SAMPLE POPULATION: Twenty-one horses. METHODS: Records of horses with chronic PSD treated by PFN were included if a preoperative ultrasonographic examination was available and at least one postoperative ultrasonographic examination. One masked observer measured the ultrasonographic cross-sectional area (CSA) of the PSL. Intraobserver reliability was determined by repeatedly measuring a subset of ultrasonographic images (n = 127). Two masked observers measured the cross-sectional area of the proximal suspensory ligament (PSL-CSA) on preoperative proton density (PD)-weighted transverse high field magnetic resonance images (n = 19 horses) . Agreements for PSL-CSA between preoperative ultrasonographic and MRI measures and between the two magnetic resonance imaging (MRI) observers were assessed. Follow up considered the horses' ability to return to exercise and their owners' satisfaction. RESULTS: The reliability of the ultrasonographic measurement of the PSL-CSA was excellent. Agreement between ultrasonographic assessment and MRI assessment of PSL-CSA was good. No difference was detected between preoperative (median, interquartile range; oblique-incidence, 2.07, 1.72-2.55; on-incidence, 2.23, 1.98-2.65) and postoperative (oblique-incidence, 2.08, 1.80-2.74; on-incidence, 2.28, 2.01-2.74) PSL-CSAs. At a median of 12 months (4-33 months), 16/20 (80%) owners reported the horse was "better" and 15/20 (75%) functioned at or above preoperative levels. CONCLUSION: Ultrasonographic measurement of the PSL-CSA was reproducible and in good agreement with MRI measurement. The PSL-CSA was not influenced by PFN. CLINICAL SIGNIFICANCE: The PSL-CSA cannot be used to guide return to function.

Use of polyamide cable ties during experimental omentectomy in adult horses with histopathological assessment.

OBJECTIVE: To report the use of nylon cable ties (NCT) for omentectomy in the horse. STUDY DESIGN: Experimental study. ANIMALS: Eight healthy adult horses. METHODS: Horses underwent nylon cable tie (NCT) ligation of the greater omentum after ventral midline celiotomy. The time required to complete the omentectomy was recorded. Horses were recovered for 14 days before repeat celiotomy, adhesions assessment, and histological examination of the omentectomy site using a proposed histologic grading scheme. The total time for omentectomy procedure and histologic score was assessed for normality. Data are expressed as mean ± standard deviation. RESULTS: NCT ligation provided sufficient hemostasis to complete the omentectomy (28 ± 15 s), without rescue ligation. No gross evidence of intra-abdominal adhesion or morbidity was associated with the omentectomy site 14 days after surgery. NCT were intact at the site of application, covered with smooth fibrous connective tissue. Adiponecrosis with minimal inflammation and fibrovascular occlusion of omental vessels was present at the surgical site. Mild inflammation was present at the NCT-tissue interface. CONCLUSION: The use of NCT resulted in fast and effective omentectomy in healthy horses without short-term evidence of inflammatory reaction or intra-abdominal adhesion. CLINICAL SIGNIFICANCE: The described technique provides an alternative for omentectomy in healthy adult horses.

Retrospective assessment of perioperative antimicrobial use for elective arthroscopy in horses.

OBJECTIVE: To describe perioperative antimicrobial use in horses undergoing elective arthroscopy. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Horses that underwent elective arthroscopy at one institution between July 2016 and May 2018, excluding those with a suspected infectious orthopedic disease or with a comorbidity that may have impacted prophylactic antimicrobial use decisions. METHODS: Medical records were reviewed to evaluate preoperative, intraoperative, and postoperative antimicrobial drug selection, dose, and timing. Associations between body weight and underdosing were evaluated by using analysis of variance, χ2 test was used for categorical comparisons, and least squares fit was used to evaluate factors associated with duration of postoperative antimicrobials. RESULTS: Among 150 horses, 149 (99.3%) received systemic preoperative antimicrobials. Only 53 (40.2%) horses were administered doses within 60 minutes of surgical incision. First incision was performed more than two half-lives after administration of sodium penicillin in 46 of 131 (35.1%) horses but in only 1 of 106 (0.8%) horses that received trimethoprim-sulfadoxine. Body weight was associated with underdosing for penicillin (P = .0075) and trimethoprim-sulfadoxine (P = .002) but not gentamicin (P = .92). Twenty-six (17%) horses received one postoperative antimicrobial dose, while antimicrobials were continued in hospital for a mean of 22.3 ± 4.4 hours after surgery in the other 123 horses. Among the 149 discharged horses, 115 (77.2%) were prescribed antimicrobials after discharge (range, 3-10 days; median, 3 days, interquartile range, 0 days). CONCLUSION: Deviations from common recommendations were apparent and provide evidence for the requirement to develop interventions to optimize perioperative prophylaxis. CLINICAL SIGNIFICANCE: Perioperative antimicrobial use practices should be regularly assessed to provide a benchmark and identify areas for intervention.

Pressure algometry for assessment of abdominal wall sensitivity in horses after ventral midline coeliotomy.

OBJECTIVE: To assess the clinical course of abdominal wall sensitivity after ventral midline coeliotomy in horses by determining mechanical nociceptive thresholds (MNTs) during hospitalization, and to determine the inter-observer reliability of pressure algometry on the abdominal wall. STUDY DESIGN: Observational, cohort study. SAMPLE POPULATION: A total of 13 horses presenting with signs of abdominal pain/colic undergoing ventral midline coeliotomy and 10 healthy horses without an abdominal incision. METHODS: Measurements were performed on days 1, 3, 5, 7 and 9 postoperatively using a pressure algometer. Measurement sites were marked left and right, abaxial to the abdominal incision. Cranial to the incision, two control points were marked. Measurements were made by one observer, blinded to the recorded MNT values. To determine inter-observer reliability, five horses (surgical group n = 2; nonsurgical group n = 3) were measured by two observers in a randomized order. RESULTS: Mean MNT values on days 5 and 7 were 9.61 Ncm-2 and 10.14 Ncm-2 in the operated group (p = 0.009 ; p = 0.005) respectively versus 13.00 Ncm-2 on day 1. Wound-associated points showed lower values than control points (p = 0.002). The nonsurgical group did not show a difference between control points and wound-associated points (p = 0.06). No significant differences were found between the surgical and the nonsurgical groups at the wound-associated points on any days measured. The inter-observer reliability was low (intraclass correlation coefficient of 0.26; Cronbach's alpha of 0.27). CONCLUSION: Operated animals showed a reduction in MNT values on days 5 and 7 when compared with day 1 and lower values for the wound-associated points when compared with the control points. Inter-observer reliability was low. Pressure algometry could be a useful tool for assessing wound sensitivity after ventral midline coeliotomy in horses, which may improve pain management postoperatively.

Assessment of systemic inflammation by time-trends of blood granulocyte count and plasma myeloperoxidase and elastase concentrations following colic surgery in horses.

OBJECTIVE: To determine changes in blood granulocyte counts and in plasma myeloperoxidase (MPO) and elastase (ELT) concentrations in surgical colic cases, and to determine the relationship between these changes and the surgical procedure performed, occurrence of postoperative ileus, and final outcome. DESIGN: Prospective clinical study conducted over a 12-month period. SETTING: University teaching hospital. ANIMALS: Fifty-three horses undergoing emergency laparotomy and surviving at least 12 hours postoperatively. INTERVENTIONS: Blood samples were taken before surgery, during surgery, at the recovery from anesthesia, and then serially until the 150th hour after the first blood sampling. Granulocyte counts were performed by an automated cell hematology analyzer. Specific ELISAs were performed for the MPO and ELT measurements. Mixed models were used to compare the time-trends of the 3 parameters. MEASUREMENTS AND MAIN RESULTS: Taking all horses together, the time-trends of MPO and ELT were not significantly different from each other, but they were significantly different from the granulocyte time-trend. The type of surgical procedure did not influence the time-trends of the 3 parameters. Significant changes in the granulocyte time-trends were associated with postoperative ileus and outcome. Significant changes in the MPO time-trends were associated with outcome. The ELT time-trends were not influenced by ileus or outcome. CONCLUSIONS: Granulocyte counts and MPO change over time and are related to the severity of the inflammatory reaction in surgical colic cases. These time-trends may allow evaluation of treatment efficacy in an effort to modulate excessive granulocyte activation and degranulation.

Dark-field microscopy in the assessment of large colon microperfusion and mucosal injury in naturally occurring surgical disease of the equine large colon.

REASON FOR PERFORMING STUDY: Intraoperative assessment of colonic viability can be challenging and largely subjective. Objective methods are often impractical. Viability is related to re-establishment of colonic perfusion; particularly microvascular perfusion. This study evaluated the utility of dark-field microscopy (DFM) of the colonic serosa as an objective method of assessing microperfusion. OBJECTIVES: To measure microvascular perfusion indices (MPI) of the pelvic flexure serosa in horses with surgical colonic lesions and correlate these with macroperfusion indices (MaPI) and histomorphometry. STUDY DESIGN: Prospective, clinical, case-control study. METHODS: Control horses and horses with colonic volvulus (LCV), displacement, and/or simple obstruction undergoing surgery had DFM video loops performed on the pelvic flexure. Total vessel density, perfused vessel density, proportion of perfusion vessels and microvascular flow index were calculated from video analysis. Macroperfusion indices (arterial blood pressure and heart rate) were recorded. Histomorphometry was used to determine a mucosal injury score. Differences between lesions for MPI, MaPI and histomorphometry were compared using ANOVA or Kruskal-Wallis statistic. Spearman correlations between MPI with MaPI were performed. Linear regression was used to assess the relationship between MPI and histomorphometry. P<0.05 was significant. RESULTS: Horses with LCV had lower perfused vessel density, proportion of microvascular perfusion vessels and flow index than horses with nonstrangulating obstructions and control horses. Macroperfusion indices were not correlated with MPI but MPI were correlated with histomorphometry. CONCLUSIONS: Dark-field microscopy is achievable in the operating room and can quantify MPI from the colonic serosa in different colonic lesions. Macroperfusion indices were not related with colonic MPI. Microvascular perfusion indices can predict the severity of histopathological change at the pelvic flexure. Derangements of MPI may be more useful indicators of colonic pathology and viability and offer a more objective assessment of intestinal injury than subjective methods. Further study is needed to determine the utility of DFM in predicting survival in horses with LCV.

Clinical application and reliability of a post abdominal surgery pain assessment scale (PASPAS) in horses.

The aim of this study was to refine a multi-dimensional scale based on physiological and behavioural parameters, known as the post abdominal surgery pain assessment scale (PASPAS), to quantify pain after laparotomy in horses. After a short introduction, eight observers used the scale to assess eight horses at multiple time points after laparotomy. In addition, a single observer was used to test the correlation of each parameter with the total pain index in 34 patients, and the effect of general anaesthesia on PASPAS was investigated in a control group of eight horses. Inter-observer variability was low (coefficient of variation 0.3), which indicated good reliability of PASPAS. The correlation of individual parameters with the total pain index differed between parameters. PASPAS, which was not influenced by general anaesthesia, was a useful tool to evaluate pain in horses after abdominal surgery and may also be useful to investigate analgesic protocols or for teaching purposes.

Racing and sales performance after unilateral or bilateral single transphyseal screw insertion for varus angular limb deformities of the carpus in 53 thoroughbreds.

OBJECTIVE: To evaluate the racing and sales performance of Thoroughbred horses with varus angular limb deformities of the carpus treated by unilateral or bilateral single transphyseal screw (STS) placement. STUDY DESIGN: Case series. ANIMALS: Thoroughbred horses (n=53). METHODS: Medical records (January 1, 2005-December 31, 2006) of yearling Thoroughbreds treated for carpal angular limb deformity by transphyseal screw insertion in the distal aspect of the radius were reviewed. Retrieved data were sex, surgery, and screw removal dates, surgical site, appearance, limb(s) affected, type of angular limb deformity, and degree of angular deviation measured by a goniometer. Racing and sales data were collected for analysis from an online racing site for all treated horses and their maternal siblings. RESULTS: No significant differences were identified between treated horses and their maternal siblings in yearling sale price, 2-year-olds in training sale price, percent starters, percent winners, and starts, earnings, and earnings/start made during the 2- and 3-year old years. CONCLUSIONS: No deleterious effects on sales or racing performance were identified after use of STS in the distal aspect of the radius of Thoroughbreds for the treatment of varus angular limb deformities of the carpus.

Clinical assessment and outcome of a single-layer technique for anastomosis of the small intestine in horses.

In order to assess postoperative outcome in horses undergoing end-to-end anastomosis of the small intestine, performed using a one-layer technique, 15 horses that underwent exploratory coeliotomy, resection of the small intestine and end-to-end anastomosis using a continuous Lembert pattern were studied. Information on the age, breed, sex, diagnosis, treatment, complications and outcome of each case were obtained from medical records. Follow-up information was obtained via telephone conversations with clients and trainers. Five of the horses had short-term postoperative complications: one had postoperative ileus (POI), colic and peritonitis, one had POI and colic, two had POI only and one had diarrhoea only. A second exploratory coeliotomy was recommended in two of the 15 horses (13 per cent). The short-term survival rate, defined as survival up to the time of discharge from the hospital, was 93.3 per cent (14 of 15 horses). The long-term survival rate, defined as survival for at least 12 months after the surgery, was 84.6 per cent (11 of 13 horses followed up).

Caudal compression of the infraorbital nerve: a novel surgical technique for treatment of idiopathic headshaking and assessment of its efficacy in 24 horses.

UNLABELLED: REASONS FOR DESIGNING AND REPORTING TECHNIQUE: Idiopathic headshaking has remarkable similarities to human neuropathic facial pain syndromes associated with post herpetic and trigeminal neuralgia. These derive from abnormal sensory function within the peripheral or central pathways of the trigeminal nerve (TgN). Limiting input from the TgN can be helpful in controlling the perception of pain. Rhizotomy of the infraorbital branch of the TgN as it emerges from the infraorbital canal has been reported but has a poor efficacy. A novel technique involves compression of the nerve at a more caudal location within the infraorbital canal and the technique requires validation. HYPOTHESIS: Caudal compression of the infraorbital nerve with platinum coils, performed in horses diagnosed with idiopathic headshaking, results in a decrease in clinical signs. METHODS: Caudal compression of the infraorbital nerve, using platinum embolisation coils, was performed under fluoroscopic guidance. Clinical records of 24 idiopathic headshakers that had undergone this procedure were reviewed. Follow-up information was obtained by telephone questionnaire with the owner or referring veterinary surgeon. RESULTS: All 24 horses had at least one surgical procedure. Median follow-up time was 6 months. There were 2 horses which had surgery 2 weeks before follow-up and these were excluded from the analysis of outcome. Following one surgery, 13/22 horses (59.0%) had a successful outcome. Of the 9 horses that did not improve, surgery was repeated in 6 cases. Two of these horses had a successful outcome. Overall, a successful outcome was obtained in 16/19 horses (84.2%). CONCLUSIONS: This surgical technique is likely to prevent input from the TgN at a more caudal location then the previously described infraorbital neurectomy. The technique requires refinement.

Racing performance following the laryngeal tie-forward procedure: a case-controlled study.

REASONS FOR PERFORMING STUDY: The laryngeal tie-forward procedure (LTFP) is becoming widely used for correction of dorsal displacement of the soft palate (DDSP) despite the absence of an evidence-based assessment of its efficacy. HYPOTHESES: The LTFP returns racing performance to preoperative baseline levels and to that of matched controls; and post operative laryngohyoid position is associated with post operative performance. DESIGN AND POPULATION: Case-controlled study of racehorses undergoing a LTFP for dorsal displacement of the soft palate at Cornell University between October 2002 and June 2007. METHODS: The presence of at least one post operative start and race earnings ($) were used as outcome variables. Controls were matched by age, breed and sex from the third race prior to surgery. A novel radiographic reference system was used to determine laryngohyoid position pre- and post operatively. Data for definitively and presumptively diagnosed cases were analysed separately. RESULTS: During the study interval, 263 racehorses presented, of which 106 were included in the study; 36 had a definitive diagnosis of DDSP and 70 a presumptive diagnosis. Treated horses were equally likely to race post operatively as controls in the equivalent race. Treated horses had significantly lower earnings in the race before surgery than matched controls. The procedure moved the basihyoid bone dorsally and caudally and the larynx dorsally and rostrally. A more dorsal post operative basihyoid position and more dorsal and less rostral laryngeal position were associated with an increased probability of racing post operatively. CONCLUSIONS: Horses undergoing a LTFP are as likely to race post operatively as matched controls. The procedure restores race earnings to preoperative baseline levels and to those of matched controls. POTENTIAL RELEVANCE: This study provides strong evidence supporting the use of the LTFP in racehorses. Further work is needed to determine the relationship between laryngohyoid conformation and nasopharyngeal stability in horses.

The use of race winnings, ratings and a performance index to assess the effect of thermocautery of the soft palate for treatment of horses with suspected intermittent dorsal displacement. A case-control study in 110 racing Thoroughbreds.

REASONS FOR PERFORMING THE STUDY: There have been no reports of the efficacy of thermocautery of the soft palate (TSP) assessed objectively as a treatment of intermittent dorsal displacement of the soft palate (DDSP). OBJECTIVE: To compare: racing performance of horses that underwent thermocautery of the soft palate with matched controls; and 'Racing Post ratings' (RPR) with prize money won (RE) and a performance index (PI) for each of the horses in the study. HYPOTHESIS: Thermocautery of the soft palate has no beneficial effect on racing performance and the 3 measures of performance are significantly related. METHODS: The inclusion criteria were fulfilled by 110 horses and each was matched with 2 controls. Changes in performance were compared statistically. RPR, RE and PI were analysed using a regression model. RESULTS: The percentage of horses that improved in performance following the procedure was 28-51% for the 3 measures of performance, compared to 21-53% for the matched controls. There was no significant effect of the procedure on the changes in RPR or RE. There was a significant effect of the procedure on the change in PI (P=0.015) with more treated horses achieving an improved PI and fewer acquiring a worse PI than matched control horses. The measures of performance showed significant correlation. CONCLUSIONS: Thermocautery of the soft palate alone may not be the most efficacious treatment of DDSP. POTENTIAL RELEVANCE: Production of a reliable measure of racehorse performance may be possible.

Effect of head position on radiographic assessment of laryngeal tie-forward procedure in horses.

OBJECTIVE: To assess the effect of head position on relative position of the larynx and hyoid apparatus in horses with palatal dysfunction, and to define a standard position for radiographic assessment of laryngeal tie-forward. STUDY DESIGN: Prospective clinical study. ANIMALS: Adult horses (n=9) with palatal dysfunction. METHODS: Left lateral radiographs of the larynx were obtained pre and postoperatively for 3 different head positions (flexed=90 degrees ; neutral=100 degrees ; extended=115 degrees ). Distance between thyrohyoid bone and thyroid cartilage was measured. Data were analyzed to investigate differences between head positions, and to compare differences between pre- and postoperative measurements. RESULTS: Head position had a significant effect on relative position of the larynx and hyoid apparatus preoperatively. There was no significant difference in postoperative measurements of the 3 head positions. A significant difference between pre- and postoperative measurements was found with the head in the neutral or extended position whereas there were no significant differences between pre- and postoperative measurements using the flexed position. CONCLUSIONS: Head position affects the relationship between the hyoid apparatus and larynx preoperatively, with greatest distance occurring when the head is extended. In a flexed position, it is not possible to ascertain whether laryngeal position has changed postoperatively. CLINICAL RELEVANCE: A standardized head position is necessary when assessing the laryngeal tie-forward procedure radiographically. An extended head position is most useful for this assessment.

Endoscopic assessment and treatment of lesions of the deep digital flexor tendon in the navicular bursae of 20 lame horses.

REASONS FOR PERFORMING STUDY: Clinical lesions of the deep digital flexor tendon and navicular bone are being reported with increasing frequency. However, the role of direct visualisation by navicular bursoscopy in the diagnosis and management of such injuries has not been explored. HYPOTHESIS: Navicular bursoscopy: 1) corroborates information obtained from other, noninvasive imaging modalities; 2) allows direct visualisation of lesions unidentified by other diagnostic modalities; 3) provides further information on morphology of lesions; and 4) permits minimally invasive surgical access to lesions. METHODS: The case records of all horses that underwent diagnostic navicular bursoscopy for the investigation of lameness admitted to 2 referral clinics (the Royal Veterinary College and Reynolds House Referrals) were evaluated retrospectively. Follow-up information was obtained by telephone questionnaire. RESULTS: Twenty-three bursae were examined endoscopically in 20 horses. Tears of the deep digital flexor tendon were seen in all horses (22 bursae). In 8 bursae, cartilage lesions were also present and in one bursa this was the only abnormal finding. Computed tomography and low field magnetic resonance imaging predicted tendon lesions in most cases, but failed to identify cartilage damage. Greater than 6 month follow-up information was available for 15 animals of which 11 were sound and 9 had returned to preoperative levels of performance. CONCLUSION: Lameness localised to the foot may result from tears of the deep digital flexor tendon and/or navicular fibrocartilage loss. Navicular bursoscopy allows comprehensive evaluation of these changes and also permits appropriate lesion management. POTENTIAL RELEVANCE: The diagnostic information obtained from and therapeutic options offered by bursoscopy justify its use in horses with clinical findings localising lameness to the navicular bursa.

Comparison of surgical versus medical treatment of nephrosplenic entrapment of the large colon in horses: 19 cases (1992-2002).

OBJECTIVE: To compare the outcome of horses with nephrosplenic entrapment of the large colon (NSELC) treated surgically or medically by rolling, administration of phenylephrine hydrochloride (or both), and exercise. DESIGN: Retrospective study. ANIMALS: 11 medically treated horses and 8 surgically treated horses with NSELC. PROCEDURE: Medical records of horses with nephrosplenic entrapment between 1992 and 2002 were reviewed. Medically treated horses were included if diagnosis and outcome of treatment of nephrosplenic entrapment were confirmed via transrectal examination and ultrasonographic examination. Surgically treated horses were included if the diagnosis was confirmed by exploratory laparotomy. Horses in which the large colon was entrapped between the spleen and body wall were not included. RESULTS: Significant differences in mean age, heart rate, and duration of colic prior to treatment were not detected between horses treated surgically or medically. Ten medically treated horses recovered without complications, and 1 died. In the surgically treated group, 6 of 8 horses recovered without complications and 2 died. Mortality rate did not differ between treatments. Duration of hospitalization for medically treated horses was significantly shorter and the cost significantly less than for surgically treated horses. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that medical treatment of horses with NSELC via administration of phenylephrine hydro-chloride, rolling during general anesthesia, or both appears to be as effective as and less expensive than surgical treatment.