Search Results

You are looking at 1 - 10 of 24 items for

  • Author or Editor: Nathaniel A. White x
  • Refine by Access: All Content x
Clear All Modify Search
in Journal of the American Veterinary Medical Association

Objective—

To determine the number of myenteric plexuses and neurons in the large colon of clinically normal horses and whether the number was decreased in the large colon of horses with colon disease.

Design—

Prospective study.

Sample Population—

Colon samples from 15 clinically normal horses and 31 horses with colon disease.

Procedure—

Samples were obtained, fixed, and stained with H&E. The number of myenteric plexuses and neurons and longitudinal muscle thickness were determined in each segment of colon for clinically normal horses. Counts for segments were compared with each other and with counts in the same segment from horses with colon disease.

Results—

Myenteric plexus and neuron densities and longitudinal muscle thickness in clinically normal horses were significantly greater in the pelvic flexure and left dorsal and transverse colons. Horses with chronic obstruction (> 24 hours' duration) or with previous obstruction had significantly lower neuron density in the pelvic flexure. Myenteric plexus density in horses with strangulating large colon torsion/volvulus was significantly less in the right ventral, right dorsal, and transverse colons, and neuron density in these horses was significantly less in all segments of colon, except the left ventral colon. Horses with colon strangulation that survived had significantly greater neuron density than horses with colon strangulation that died. Enteroglial cell numbers were increased in myenteric plexuses of horses with acute and chronic obstruction.

Clinical Implications—

Myenteric plexus and neuron densities can be estimated by evaluating linear counts of H&E-stained colon samples. Enteroglial cells may increase in number in response to myenteric plexus inflammation, which may affect bowel function. (J Am Vet Med Assoc 1997;210:928–934)

Free access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Summary

Medical records from all horses with large colon impaction admitted between 1985 and 1991 were examined. Large colon impaction was diagnosed in 147 of 1,100 (13.4%) horses with colic. One hundred thirty horses were admitted for further evaluation of acute onset of abdominal pain after having been examined and treated by referring veterinarians, and 17 horses that were hospitalized for unrelated medical problems developed large colon impaction. Female horses (92/ 147; 62.6%) were more commonly affected than males. The age ranged from 1 to 29 years (median, 7.1 years). Mean duration of clinical signs of abdominal pain prior to referral was 32 hours. At admittance, signs of abdominal pain were not detectable in 70/147 (48%) horses, and were mild in 50 34%), moderate in 16 (11%), and severe in 11 (7%). Heart rate ranged from 30 to 86 beats/min (median, 44 beats/min), and most horses had a decrease in gastrointestinal sounds. Transrectal palpation was used to identify the impaction location as being the pelvic flexure in 103 (70.1%) horses, colon on the left side in 30 (20.4%) horses, and colon on the right side in 14 (9.5%) horses. All 147 horses received fluids iv and nonsteroidal anti-inflammatory medications or sedatives, including flunixin meglumine (124 horses, 84.3%) xylazine hydrochloride (81, 55%), butorphanol (6, 0.04%), and detomidine hydrochloride (9, 0.04%). Duration of medical treatment required to resolve the impaction ranged from 1 to 6 days (mean, 2 days). In addition to medical treatment, 24 (16.3%) horses also required surgery.

Analysis of results of examinations performed at the time of admission revealed significant (P < 0.05) differences for heart rate, respiratory rate, number of wbc, blood lactate concentration, and total protein concentration in peritoneal fluid between horses that lived vs horses that died or were euthanatized. Horses that had surgery had a significantly (P < 0.05) higher fatality rate. Long-term survival rate was higher (P $ 0.05) for horses treated medically.

Most horses with large colon impaction can be treated medically, and those horses have a good prognosis. Surgery usually is not necessary and may pose additional risks because of the possibility of bowel rupture during the operation.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine outcome of percutaneous ultrasound-guided desmoplasty with simultaneous fasciotomy for proximal suspensory desmitis (ie, desmitis of the origin of the suspensory ligament) in horses that have not responded to stall rest.

Design—Retrospective case series.

Animals—27 horses.

Procedures—Medical records of horses with proximal suspensory desmitis treated by means of desmoplasty with fasciotomy were reviewed. Follow-up information was obtained through telephone conversations with owners and trainers of the horses or by examination of horses at the hospital.

Results—23 of the 27 (85%) horses, including 3 of 4 horses with forelimb lesions and 20 of 23 horses with hind limb lesions, were able to return to full work after surgery and rehabilitation. All horses had ultrasonographic evidence of healing of suspensory ligament lesions.

Conclusions and Clinical Relevance—Results suggest that desmoplasty with fasciotomy is a viable treatment option in horses with proximal suspensory desmitis that have not responded to stall rest.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine clinical, scintigraphic, radiographic, and arthroscopic findings and results of treatment in horses with lameness attributable to subtle osteochondral lesions of the shoulder joint.

Design—Retrospective study.

Animals—15 horses.

Procedure—Medical records were reviewed, and results of physical examination, scintigraphy, radiography, arthroscopy, and treatment were recorded.

Results—Severity of lameness ranged from grade 1 to 4. Response to shoulder flexion or extension was variable. Twelve horses had a narrow upright foot. Intra-articular anesthesia of the shoulder joint localized the cause of the lameness to the shoulder joint in 9 of 10 horses. Scintigraphic abnormalities were detected in 4 of 6 horses. Radiographic lesions were subtle and included glenoid sclerosis, focal glenoid lysis, small glenoid cysts, and alterations in the humeral head contour. Arthroscopic evaluation confirmed clefts in the glenoid cartilage, glenoid cysts, a humeral head cyst, fibrillation of the humeral head cartilage, cartilage fragmentation, or a nondisplaced fracture of the humeral head. After treatment, 12 horses returned to their previous level of performance, 1 was sound for light riding, 1 remained lame, and 1 was euthanatized because of chronic lameness.

Conclusion and Clinical Relevance—Results suggest that a combination of physical examination, scintigraphy, and radiography is necessary to diagnose subtle osteochondral lesions of the shoulder joint in horses. Arthroscopy can be used to confirm the diagnosis and treat cartilage and subchondral bone lesions. Young and middle-aged horses with subtle osteochondral lesions of the shoulder joints have a good prognosis for return to performance following arthroscopic treatment. (J Am Vet Med Assoc 2000;217:1878–1882)

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether intraluminal distention and subsequent decompression of the equine jejunum affects intestinal blood flow, hemodynamics, and microvascular permeability.

Animals—5 healthy adult horses.

Procedure—Horses were anesthestized and underwent exploratory laparotomy. Two jejunal segments were identified as sham-operated or instrumented segments. After baseline values were obtained, intraluminal distention was created in the experimental segment to induce an intraluminal pressure of 18 cm H2O. After 120 minutes of distention, the intestine was decompressed for 120 minutes. Mesenteric blood flow, oxygen delivery, oxygen consumption, microvascular permeability, wet weight-to-dry weight ratio, neutrophil infiltration, and vascular resistance were determined and comparisons made among control, sham-operated, and experimental segments.

Results—Mean jejunal blood flow was 21.4 ml/min per kg. There was a significant decrease in mesenteric blood flow to the distended intestine (13.4 ml/min per kg). Blood flow increased significantly during the decompression period (340% of baseline blood flow). Intraluminal distention and subsequent decompression resulted in a significant increase in microvascular permeability, as determined by the osmotic reflection coefficient. Oxygen delivery and oxygen content decreased significantly during the distention period and increased during decompression. Morphologic evaluation revealed a significant increase in edema and neutrophil infiltration after distention and decompression, compared with results for the sham-operated or control segments.

Conclusions and Clinical Relevance—Intraluminal distention and decompression of the equine jejunum results in low-flow ischemia and edema, which may contribute to adhesions and ileus in the postoperative period after surgery for obstructions of the small intestines. (Am J Vet Res 2001;62:225–236)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To identify factors associated with outcome (ie, survival and return to function) following treatment of horses with septic tenosynovitis.

Design—Retrospective case series.

Animals—51 horses with septic tenosynovitis.

Procedures—Information was obtained from medical records and through follow-up conversations with owners. Factors analyzed for an association with outcome included affected limb, etiology, duration of clinical signs prior to examination, presence of complications, primary treatment, secondary treatments, number of surgical procedures, and hospitalization time.

Results—Concurrent complications were identified in 41 (80%) horses. The primary treatment consisted of through-and-through lavage in 26 (51%) horses, tenoscopy in 20 (39%), and tenosynoviotomy combined with lavage in 5 (10%). Forty (78%) horses were discharged, and 37 (73%) survived at least 1 year after surgery; 21 of the 37 (57%) returned to their previous or a higher level of performance. Percentages of horses that survived 1 year after discharge and percentages that returned to their intended use did not vary significantly among treatments. Horses with tendon rupture or sepsis of an adjacent joint were significantly less likely to survive. Horses with tendon injury or pannus were significantly less likely to return to their intended use.

Conclusions and Clinical Relevance—Results suggested that various factors were associated with outcome in horses with septic tenosynovitis. However, surgical technique was not found to be associated with survival rate or rate of return to intended use.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine clinical and ultrasonographic abnormalities in horses with primary desmitis of the palmar or plantar annular ligament (PAL) and the response to treatment.

Design—Retrospective study.

Animals—25 horses.

Procedure—Data collected from medical records included signalment, horse use, affected limb, severity and duration of lameness, results of diagnostic tests performed, ultrasonographic findings, treatment, and outcome.

Results—All horses had a prominent swelling in the region of the affected PAL, and signs of pain were evident during palpation of the swelling. In all horses, the affected PAL was thicker than normal as determined ultrasonographically. Twenty horses had hypoechoic regions in the PAL. Four horses, including 1 horse with 3 affected limbs, were treated by means of PAL desmoplasty, 9 were treated by means of PAL desmotomy, and 12 were treated with rest. Follow-up information was available for 21 horses. All 4 horses that underwent PAL desmoplasty, 4 of 7 horses that underwent PAL desmotomy, and 7 of 10 horses treated with rest alone became sound.

Conclusions and Clinical Relevance—Results suggest that primary desmitis of the PAL may be a cause of lameness in horses. Although significant differences in outcome between horses treated with rest alone versus PAL desmoplasty versus PAL desmotomy were not identified, because it is less invasive, PAL desmoplasty should be considered for treatment of horses with PAL desmitis that do not respond to conservative treatment and do not have any evidence of constriction of the digital flexor tendons. (J Am Vet Med Assoc 2005;226:83–86)

Full access
in Journal of the American Veterinary Medical Association