Objective—To assess gait abnormalities associated with selective anesthesia of the suprascapular nerve (SSN) achieved by use of perineural catheterization and thereby determine the function of that nerve as it relates to gait in horses.
Animals—3 adult horses with no preexisting clinically apparent lameness at a walk.
Procedure—Each horse was anesthetized; the right SSN was exposed surgically for placement of a perineural catheter to permit delivery of 1 mL of 2% mepivacaine hydrochloride. Six hours after recovery from anesthesia, each horse was videotaped while walking (50-step data acquisition period) before and after administration of mepivacaine. Videotapes were reviewed and the proportion of abnormal steps before and after selective SSN anesthesia was assessed. A step was considered abnormal if a marked amount of scapulohumeral joint instability (ie, lateral luxation of the proximal portion of the humerus) was observed during the weight-bearing phase of the stride.
Results—Clinically apparent gait dysfunction was detected in all 3 horses following perineural administration of the local anesthetic agent. Anesthesia of the SSN resulted in scapulohumeral joint instability as evidenced by consistent lateral excursion of the shoulder region during the weight-bearing phase of gait at a walk. The proportion of abnormal steps before and after SSN anesthesia was significantly different in all 3 horses.
Conclusions and Clinical Relevance—These data support the role of the SSN in shoulder joint stability in horses and define SSN dysfunction as 1 mechanism by which the syndrome and gait dysfunction clinically referred to as sweeny may develop.
Case Description—A 10-year-old Longhorn cow pregnant with a valuable fetus was evaluated because of progressive inspiratory dyspnea of 6 weeks' duration.
Clinical Findings—Physical examination findings were consistent with upper respiratory tract obstruction. A large pedunculated soft tissue mass was evident in the mid-dorsal aspect of the pharynx during palpation and endoscopic examination. Results of microscopic examination of transendoscopic fine-needle aspirates and a biopsy specimen were suggestive of a bacterial granuloma.
Treatment and Outcome—Transtracheal intubation was performed, and the mass was excised with a chain écraseur. Results of histologic examination were consistent with a diagnosis of actinobacillosis. The owner reported that the cow was doing well without any recurrence of respiratory distress 8 months after surgery.
Clinical Relevance—Findings suggested that pharyngeal granuloma resulting from actinobacillosis should be included in the differential diagnoses when examining mature cattle with upper respiratory tract obstruction and that a chain écraseur may be useful for excising soft tissue pharyngeal masses in cattle.
Objective—To quantitatively compare 3 commonly
used treatments for navicular syndrome (NS) in horses:
heel-elevation shoeing alone, heel-elevation shoeing
and phenylbutazone administration, heel-elevation
shoeing and injection of the distal interphalangeal
joint (DIPJ) with triamcinolone acetonide (TA), and all
3 treatments in combination.
Animals—12 horses with NS.
Procedure—A force plate was used to measure
baseline peak vertical ground reaction force (PVGRF)
of the forelimbs. Each horse's forelimbs were shod
with 3° heel-elevation horseshoes; PVGRF was measured
24 hours and 14 days after shoeing. Fourteen
days after shoeing (following data collection),
phenylbutazone (4.4 mg/kg, IV, q 12 h) was administered
(5 treatments). Two hours after the fifth treatment,
PVGRF was measured; TA (6 mg) was injected
into the DIPJ of the forelimb that generated the lower
baseline PVGRF. Fourteen days later, PVGRF was
measured. Phenylbutazone was administered as
before, and PVGRF was measured. Percentage body
weight of force (%BWF) was calculated from PVGRF
measurements and used for comparisons.
Results—14 days after shoeing, mean %BWF in both
forelimbs significantly increased from baseline; additional
administration of phenylbutazone significantly
increased %BWF applied from the more lame forelimb.
Compared with shoeing alone, there was no significant
change in %BWF after injection of the DIPJ
with TA in shod horses.
Conclusions and Clinical Relevance—Heel-elevation
shoeing alone and in combination with phenylbutazone
administration quantitatively decreased lameness
in horses with NS. Although not significant, additional
DIPJ injection with TA resulted in further quantitative
decrease in lameness, compared with that
achieved via shoeing alone. (Am J Vet Res
Case Description—A 7-year-old sexually intact male Thoroughbred racehorse was evaluated because of exercise intolerance, respiratory tract noise, and coughing when eating.
Clinical Findings—A persistent dorsal displacement of the soft palate was identified during endoscopic examination of the upper portions of the respiratory tract. Radiography of the pharyngeal and laryngeal regions revealed a hypoplastic epiglottis that was ventral to, and not in contact with, the soft palate. The horse was anesthetized, and an oral endoscopic examination revealed a subepiglottic frenulum that had resulted in the dorsal displacement of the soft palate.
Treatment and Outcome—The frenulum was transected transendoscopically by use of a diode laser. Twenty-four hours following surgery, repeat endoscopic and radiographic examinations revealed that the epiglottis had returned to its correct anatomic position in relation to the soft palate. Four weeks after surgery, endoscopy of the upper portions of the airway revealed recurrence of the dorsal displacement of the soft palate.
Clinical Relevance—A subepiglottic frenulum should be considered as a cause of persistent dorsal displacement of the soft palate in horses. An endoscopic examination of the oropharyngeal region should be performed in horses prior to undertaking any surgical interventions to treat persistent dorsal displacement of the soft palate.
Objective—To compare effects of the locking-loop
suture pattern (LLP) and 3-loop pulley (3LP) suture
pattern for tenorrhaphy on the intrinsic vasculature of
the superficial digital flexor tendon (SDFT) of horses
in vitro after surgery.
Sample Population—16 forelimbs obtained from 8
Procedure—Tenotomy and subsequent tenorrhaphy
was performed in anesthetized horses. Following systemic
administration of heparin, horses were euthanatized
and the limbs were removed and placed
under tension to load the flexor tendons. The intrinsic
vasculature was then perfused with a mixture of barium
sulfate and water. Four-millimeter sections of the
SDFT were prepared for microangiographic analysis.
Mean vessel density was calculated for each section
by use of a grid consisting of 1.5-mm2 vascular
assessment squares (VAS). Comparisons were made
among the control, LLP, and 3LP groups.
Results—Mean ± SD vessel density was 3.11 ± 0.38,
1.47 ± 0.47, and 2.01 ± 0.63 perfused vessels/1.5 mm2
for control, LLP, and 3LP groups, respectively.
Significant differences in vascular density were
detected between the control and 3LP groups, control
and LLP groups, and LLP and 3LP groups.
Conclusions and Clinical Relevance—Use of the
LLP and 3LP pattern has deleterious effects in vitro on
the intrinsic vasculature of the SDFT. However, the
3LP pattern was less disruptive to the intrinsic vasculature,
compared with the effects for the LLP. Use of
the 3LP tenorrhaphy suture pattern in clinical situations
may result in less damage to the intrinsic vasculature
of the SDFT of horses during convalescence.
( Am J Vet Res 2004;65:279–282)