Objective—To compare postoperative complications,
short- and long-term survival, and surgical times for
hand-sewn end-to-end (EE), stapled functional end-toend
(FEE), and stapled side-to-side (SS) anastomotic
techniques for jejunal resection in horses.
Procedure—Medical records were reviewed to
obtain signalment, diagnosis, treatment, and outcome
for horses that underwent jejunojejunostomy in
our hospital. Only horses that recovered from anesthesia
were included in the study.
Results—Among the 59 horses, there were 33 EE,
15 FEE, and 11 SS anastomoses. No difference was
found in duration of surgery among the 3 techniques.
The most common postoperative complications
were colic episodes (56%), ileus (53%), diarrhea
(20%), and adhesions (15%). Horses with SS anastomosis
had a significantly shorter duration of postoperative
ileus than the EE group did. No significant
difference in duration of postoperative ileus was
found among the other groups. No difference was
found among the 3 anastomotic techniques in regard
to survival rate at the time of discharge, 6 months
after surgery, or 1 year after surgery. Overall survival
rates after jejunal anastomosis were 88% at the time
of discharge, 65% at 6 months after surgery, and
57% at ≥ 1 year after surgery.
Conclusions and Clinical Relevance—The handsewn
EE, stapled FEE, and stapled SS anastomotic
techniques should be considered equivalent methods
for small intestinal anastomosis in the horse.
However, the stapled SS technique may be preferred
because of possible decreased duration of postoperative
ileus. (J Am Vet Med Assoc 2002;220:215–218)
Objective—To determine the effects of hypoglossal nerve block and electrical stimulation of the thyrohyoideus muscles on position of the larynx and hyoid apparatus in resting horses.
Animals—16 healthy horses that underwent hypoglossal nerve block and 5 healthy horses that underwent electrical stimulation of the thyrohyoideus muscles.
Procedures—Horses underwent bilateral hypoglossal nerve block or electrical stimulation of the thyrohyoideus muscles. Positions of the basihyoid bone, ossified part of the thyroid cartilage, and articulations of the thyrohyoid bones and thyroid cartilage were determined in radiographic images obtained before and after performance of hypoglossal nerve blocks or during thyrohyoideus muscle stimulation. Radiographic images were obtained with the heads of horses in neutral (thyrohyoideus muscle stimulation) or neutral and extended (hypoglossal nerve block) positions. Radiographic images of horses obtained after performance of hypoglossal nerve blocks were also evaluated to detect dorsal displacement of the soft palate.
Results—Hypoglossal nerve blocks did not induce significant changes in the positions of evaluated anatomic sites in radiographic images obtained in neutral or extended head positions. Hypoglossal nerve block did not induce dorsal displacement of the soft palate in horses at rest. Bilateral thyrohyoideus muscle stimulation induced significant dorsal movement (mean ± SD change in position, 18.7 ± 6.8 mm) of the ossified part of the thyroid cartilage; rostral movement of evaluated anatomic structures was small and not significant after thyrohyoideus muscle stimulation.
Conclusions and Clinical Relevance—Bilateral electrical stimulation of the thyrohyoideus muscles in horses in this study induced dorsal laryngeal movement.
OBJECTIVE To describe the ultrasonographic changes in the cricoarytenoideus dorsalis (CAD) and cricoarytenoideus lateralis (CAL) muscles of horses before and at various times during the 32 weeks after unilateral neurectomy of the right recurrent laryngeal nerve.
ANIMALS 28 healthy Standardbreds.
PROCEDURES For each horse, the appearance of the CAD and CAL muscles on the right (neurectomized) and left (control) sides was serially monitored ultrasonographically by percutaneous (CAD and CAL) and transesophageal (CAD) approaches. The ultrasonographic images were assessed to determine the mean pixel intensity, muscle thickness, and appearance grade, and comparisons were made between the muscles of the neurectomized and control sides.
RESULTS The muscle appearance grade and mean pixel intensity for the CAL and CAD muscles on the neurectomized side were significantly increased by 2 and 4 weeks, respectively, after the neurectomy. The transesophageal approach enhanced the ultrasonographic visibility of the CAD muscle and allowed us to detect a significant decrease in the thickness of the CAD muscle on the neurectomized side over time, compared with thickness of the CAD muscle on the control side.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested ultrasonography can be used to successfully assess the CAL and CAD muscles of horses. A qualitative grading scheme was sufficient for successful detection and monitoring of muscle atrophy and reduced the need for image standardization. The transesophageal approach described for assessment of the CAD muscle warrants further investigation.
To determine setting and temperature properties of diluted polymethyl methacrylate (PMMA) bone cement in vitro to assess utility for vocal fold augmentation in horses.
4 dilutions of PMMA equivalent to volumes of 15 mL, 20 mL, 25 mL, and 30 mL PMMA powder (PMMAp) in 10 mL solvent.
For each volume PMMAp, setting times (tset), peak temperatures (Tmax), and times to peak temperature (tmax) were determined using a temperature data logger in a 4-mL volume of PMMA. Injectability was assessed in vitro by documenting the force required to inject 0.2 mL PMMA through an 18-gauge 3.5-inch spinal needle attached to a 6-mL syringe at 1-minute intervals. Working time (twork) was calculated from a linear regression of injectability.
Peak temperatures increased with increasing volume of PMMAp: 56 °C, 86 °C, 99 °C, and 101 °C. Times for tset, twork, and tmax were inversely proportional to PMMA concentrations, resulting in tset of 23, 21, 17, and 14 minutes; twork of 22.75, 12.25, 7, and 4 minutes; and tmax of 28, 24, 19, and 16 minutes, respectively, for 15, 20, 25, and 30 mL PMMAp. Pairwise comparisons for all analyses were significant apart from Tmax for 25 and 30 mL PMMAp (P = .96) and twork for 20 and 25 mL PMMAp (P = .06).
Decreasing the concentration of PMMA bone cement resulted in longer working times and setting times; however, peak temperatures did not differ between the 2 strongest concentrations. Further research is warranted to quantify diluted PMMA properties for in vivo use for vocal fold augmentation in horses.
Objective—To determine the phase and quantitate the electromyographic (EMG) activity of the genioglossus, geniohyoideus, hyoepiglotticus, omohyoideus, sternohyoideus, sternothyroideus, and thyrohyoideus muscles of clinically normal horses during strenuous exercise.
Animals—7 clinically normal adult horses (2 Thoroughbreds and 5 Standardbreds).
Procedures—Bipolar electrodes were surgically implanted in the aforementioned muscles, and horses were subjected to an incremental exercise test on a high-speed treadmill. The EMG, heart rate, respiratory rate, and static pharyngeal airway pressures were measured during exercise. The EMG was measured as mean electrical activity (MEA). The MEA values for maximal exercise intensity (13 or 14 m/s) were expressed as a percentage of the MEA measured at an exercise intensity of 6 m/s.
Results—MEA was detected during expiration in the genioglossus, geniohyoideus, sternohyoideus, and thyrohyoideus muscles and during inspiration in the hyoepiglotticus and sternothyroideus muscles. Intensity of the MEA increased significantly with exercise intensity in the genioglossus, geniohyoideus, and hyoepiglotticus muscles. Intensity of the MEA increased significantly in relation to expiratory pharyngeal pressure in the geniohyoideus and hyoepiglotticus muscles.
Conclusions and Clinical Relevance—Once exercise intensity reached 6 m/s, no quantifiable additional increase in muscular activity was detected in the omohyoideus, sternohyoideus, sternothyroideus, and thyrohyoideus muscles. However, muscles that may affect the diameter of the oropharynx (genioglossus and geniohyoideus muscles) or rima glottis (hyoepiglotticus muscle) had activity correlated with the intensity of exercise or expiratory pharyngeal pressures. Activity of the muscles affecting the geometry of the oropharynx may be important in the pathophysiologic processes associated with nasopharyngeal patency.
OBJECTIVE To develop and assess the feasibility, repeatability, and safety of an ultrasound-guided technique to stimulate the first cervical nerve (FCN) at the level of the alar foramen of the atlas of horses.
ANIMALS 4 equine cadavers and 6 clinically normal Standardbreds.
PROCEDURES In each cadaver, the FCN pathway was determined by dissection, and any anastomosis between the first and second cervical nerves was identified. Subsequently, each of 6 live horses underwent a bilateral ultrasound-guided stimulation of the FCN at the alar foramen 3 times at 3-week intervals. After each procedure, horses were examined daily for 5 days.
RESULTS In each cadaver, the FCN passed through the alar foramen; a communicating branch between the FCN and the accessory nerve and anastomoses between the ventral branches of the FCN and second cervical nerve were identified. The anastomoses were located in the upper third of the FCN pathway between the wing of the atlas and the nerve's entry in the omohyoideus muscle. Successful ultrasound-guided electrical stimulation was confirmed by twitching of the ipsilateral omohyoideus muscle in all 6 live horses; this finding was observed bilaterally during each of the 3 experimental sessions. No complications developed at the site of stimulation.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that ultrasound-guided stimulation of the FCN at the alar foramen appears to be a safe and straightforward procedure in horses. The procedure may have potential for use in horses with naturally occurring recurrent laryngeal neuropathy to assess reinnervation after FCN transplantation or nerve-muscle pedicle implantation in the cricoarytenoideus dorsalis muscle.
Objective—To investigate whether upper airway
sounds of horses exercising with laryngeal hemiplegia
and alar fold paralysis have distinct sound characteristics,
compared with unaffected horses.
Animals—6 mature horses.
Procedure—Upper airway sounds were recorded in
horses exercising on a high-speed treadmill at maximum
heart rate (HRMAX) under 3 treatment conditions
(ie, normal upper airway function [control condition],
and after induction of left laryngeal hemiplegia or bilateral
alar fold paralysis) in a randomized crossover
design. Fundamental frequency, spectrograms using
Gabor transform, and intensity characteristics of
acquired sounds (peak sound level [soundpeak] and
highest frequency of at least –25 dB sound intensity
[F25max]) were evaluated.
Results—Evaluation of the fundamental frequency of
the time domain signal was not useful. Sensitivity and
specificity (83 and 75%, respectively) of spectrograms
were greatest at maximal exercise, but the
exact abnormal condition was identified in evaluation
of only 12 of 18 spectrograms. Increased accuracy
was obtained using soundpeak and F25max as discriminating
variables. The use of soundpeak discriminated
between control and laryngeal hemiplegia conditions
and F25max between laryngeal hemiplegia and alar fold
paralysis conditions. This increased the specificity of
sound analysis to 92% (sensitivity 83%) and accurately
classified the abnormal state in 92% of affected
Conclusions and Clinical Relevance—Sound analysis
might be a useful adjunct to the diagnosis and evaluation
of treatment of horses with upper airway obstruction,
but would appear to require close attention to
exercise intensity. Multiple measurements of recorded
sounds might be needed to obtain sufficient accuracy
for clinical use. (Am J Vet Res 2002;63:1707–1713)
Objective—To compare cardiac troponin I (cTnI) concentrations determined by use of a point-of-care analyzer with values determined by use of a bench-top immunoassay in plasma samples obtained from clinically normal horses with and without experimentally induced cardiac disease, and to establish a reference range for plasma equine cTnI concentration determined by use of the point-of-care analyzer.
Animals—83 clinically normal horses, 6 of which were administered monensin to induce cardiac disease.
Procedures—A blood sample was collected from each of the 83 clinically normal horses to provide plasma for analysis by use of the point-of-care analyzer; some of the same samples were also analyzed by use of the immunoassay. All 83 samples were used to establish an analyzer-specific reference range for plasma cTnI concentration in clinically normal horses. In 6 horses, blood samples were also collected at various time points after administration of a single dose of monensin (1.0 to 1.5 mg/kg) via nasogastric intubation; plasma cTnI concentration in those samples was assessed by use of both methods.
Results—The analyzer-specific reference range for plasma cTnI concentration in clinically normal horses was 0.0 to 0.06 ng/mL. Following monensin treatment in 5 horses, increases in plasma cTnI concentration determined by use of the 2 methods were highly correlated (Pearson correlation, 0.83). Peak analyzer-determined plasma cTnI concentrations in monensin-treated horses ranged from 0.08 to 3.68 ng/mL.
Conclusions and Clinical Relevance—In horses with and without experimentally induced cardiac disease, the point-of-care analyzer and bench-top immunoassay provided similar values of plasma cTnI concentration.