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Biomedical subjects

S A Hopper

Publications and source records attributed to S A Hopper.

17 recordsLinked to original sources
PubMed2007

Racing performance after arthroscopic removal of apical sesamoid fracture fragments in Thoroughbred horses age < 2 years: 151 cases (1989--2002).

REASONS FOR PERFORMING STUDY: Studies on arthroscopic removal of apical proximal sesamoid fracture fragments in Thoroughbred (TB) horses age > or = 2 years have reported a high success rate. However, there are no reports documenting the racing prognosis of TB horses that undergo such surgery as weanlings or yearlings. OBJECTIVES: To describe the incidence of apical proximal sesamoid fractures in immature TB horses, age < 2 years and determine probability and quality of racing performance after arthroscopic removal of such fractures in 151 TB weanlings and yearlings. METHODS: The medical records of TB horses age < 2 years that underwent arthroscopic surgery for removal of apical proximal sesamoid fracture fragments were reviewed. Follow-up information was obtained from race records. Student's t tests were used to compare performance variables of operated racehorses to that of their maternal siblings. RESULTS: Ninety-two percent (139/151) of fractures occurred in the hindlimbs and 8% (11/151) in the forelimbs (fracture of both fore- and hindlimb, n = 1). Horses with forelimb fractures had a greatly reduced probability of racing (55%) compared to those with hindlimb fractures (86%). Overall, 84% of the horses raced post operatively and had performance records similar to that of their maternal siblings, 78% (787/1006) of which raced. CONCLUSIONS: Arthroscopic removal of apical proximal sesamoid fracture fragments in TB weanlings and yearlings carries an excellent prognosis for racing in horses with hindlimb fractures and a reduced prognosis in those with forelimb fractures. Medial fractures of the forelimb carry the worst prognosis. POTENTIAL RELEVANCE: The determination of prognosis increases knowledge on apical sesamoid bone fractures and potential for arthroscopic restoration of the ability to race; and enables the value of yearlings for subsequent sale to be established.

Age Factors↗
PubMed2006

Racing performance after arthroscopic removal of apical sesamoid fracture fragments in Thoroughbred horses age > or = 2 years: 84 cases (1989-2002).

REASONS FOR PERFORMING STUDY: Studies have shown that surgical removal of apical fracture fragments in Standardbred racehorses carries the best prognosis for return to racing performance, but there are no reports involving mature Thoroughbred (TB) racehorses. OBJECTIVES: To describe the incidence of apical proximal sesamoid fractures in TB racehorses and determine probability and quality of racing performance after arthroscopic removal of such fractures in TB racehorses age > or = 2 years. METHODS: Medical records and pre- and post operative race records of TB racehorses age > or = 2 years that underwent arthroscopic surgery for removal of apical proximal sesamoid fracture fragments were reviewed. RESULTS: Sixty-four percent of fractures occurred in the hindlimbs and 36% in the forelimbs. Horses with forelimb fractures had a reduced probability of return to racing (67%) compared to those with hindlimb fractures (83%), but the majority (77%) of treated horses recovered to return to race post operatively. Horses with medial forelimb fractures raced at only a 47% rate; those with suspensory desmitis at 63%. Unlike Standardbreds, there was no difference in probability of racing post operatively between horses that had, and had not, raced preoperatively. CONCLUSIONS: Data show that arthroscopic removal of apical proximal sesamoid fracture fragments is successful at restoring ability to race in skeletally mature TB horses without evidence of severe suspensory ligament damage. Prognosis for return to racing is excellent (83%) in horses with hindlimb fractures and good (67%) in those with forelimb fractures. Medial fractures of the forelimb have the worst prognosis. POTENTIAL RELEVANCE: The determination of prognosis for differing sites in TB racehorses should increase knowledge of apical proximal sesamoid bone fractures and improve communication from veterinarian to owner, and trainer, on the potential for arthroscopic restoration of the ability to race.

Age Factors↗
PubMed2003

Dystocia in a referral hospital setting: approach and results.

REASONS FOR PERFORMING STUDY: Dystocia in the mare is an emergency in which duration has a profound effect on survival of the foal. Specific examination of the effects of dystocia duration on foal survival provides information to enable horse care personnel and veterinarians to manage these cases more effectively and maximise the chances of obtaining a live foal. HYPOTHESIS: Dystocia duration would have a negative impact on foal survival while method of dystocia resolution would not have an effect on foal survival. Additionally, we were interested in determining the effects of dystocia on subsequent fertility. METHODS AND RESULTS: In the years 1986-1999, 247 dystocias were admitted. Of these, 91 % resulted in survival and discharge of the mare, 42% in delivery of a live foal, and 29% of foals survived to discharge. Period from hospital arrival to delivery for foals alive at discharge (23.0 +/- 14.1 mins) was not significantly different than for foals not surviving (24.8 +/- 10.6 mins) (P > 0.05); and from chorioallantoic rupture to delivery for foals alive at discharge (71.7 +/- 343 mins) was significantly less than for foals not surviving (853 +/- 37.4 mins) (P < 0.05). Average predystocia live foaling rates for all mares with available records was 84%. Overall post dystocia live foaling rates over the entire period of this study were 67%. Of mares bred in the year of the dystocia, 59% had a live foal in the year following. CONCLUSIONS: Based on these results, dystocia duration has a significant effect on foal survival and resolution methods should be chosen to minimise this time, as the difference between mean dystocia duration for foals that lived and those that did not in this study was 13.6 mins. Post dystocia foaling rates reported here are higher than previously reported for both same-season and overall breedings, indicating same-season breeding may be rewarding for select dystocia cases. POTENTIAL RELEVANCE: Dystocia resolution methods that minimise delivery time may maximise foal survival. Post dystoicia breeding may be rewarding in select cases.

Animals↗
PubMed2000

In vitro comparison of transfixation and standard full-limb casts for prevention of displacement of a mid-diaphyseal third metacarpal osteotomy site in horses.

OBJECTIVE: To compare transfixation and standard full-limb casts for prevention of in vitro displacement of a mid-diaphyseal third metacarpal osteotomy site in horses. SAMPLE POPULATION: 6 forelimbs from 6 horses euthanatized for reasons not related to the musculoskeletal system. PROCEDURE: A 30 degrees osteotomy was performed in the mid-diaphysis of the third metacarpal bone. Two 4.5-mm cortical bone screws were placed across the osteotomy site to maintain alignment during casting. Two 6.35-mm Steinmann pins were placed from a lateral-to-medial direction in the distal aspect of the radius. A full-limb cast that incorporated the pins was applied. An extensometer was positioned in the osteotomy site through a window placed in the dorsal aspect of the cast, and after removal of the screws, displacement was recorded while the limb was axially loaded to 5,340 N (1,200 lb). Pins were removed, and the standard full-limb cast was tested in a similar fashion. RESULTS: The transfixation cast significantly reduced displacement across the osteotomy site at 445 N (100 lb), 1,112 N (250 lb), 2,224 N (500 lb), and 4,448 N (1,000 lb), compared with the standard cast. CONCLUSION AND CLINICAL RELEVANCE: A full-limb transfixation cast provides significantly greater resistance than a standard full-limb cast against axial collapse of a mid-diaphyseal third metacarpal osteotomy site when the bone is placed under axial compression. Placement of full-limb transfixation casts should be considered for the management of unstable fractures of the third metacarpal bone in horses.

Animals↗
PubMed1998

Effect of different full-limb casts on in vitro bone strain in the distal portion of the equine forelimb.

OBJECTIVE: To determine the ability of a full-limb transfixation pin cast to protect the distal portion of the equine forelimb from weight-bearing forces by measuring bone strain in vitro on cadaver limbs loaded in a mechanical testing machine. SAMPLE POPULATION: 6 forelimbs from 6 horses. PROCEDURE: Each limb was instrumented with 3 unidirectional metal foil electrical resistant strain gauges. Gauges were placed on the dorsal aspect of the distal portion of the radius and the mid-dorsal portion of the cortex of the third metacarpal bone and the first phalanx. Each limb was tested 3 times, once supported with a transfixation pin cast, once supported by a standard full-limb cast, and finally, uncast. The limbs were tested in a mechanical testing machine under axial loads ranging from 100 to 1,000 lb, and bone strains were recorded at each load. RESULTS: Compared with values for the uncast limb, the transfixation pin cast and the standard full-limb cast significantly (P < 0.001) reduced bone strain on the distal portion of the radius, third metacarpal bone, and first phalanx. Compared with the standard full-limb cast, the transfixation pin cast significantly (P < 0.001) reduced bone strain on the first phalanx. CONCLUSION AND CLINICAL RELEVANCE: Compared with the standard full limb cast, the full-limb transfixation pin cast is more protective of the first phalanx.

Animals↗
PubMed1998

Effect of pin hole size and number on in vitro bone strength in the equine radius loaded in torsion.

OBJECTIVE: To determine the effect of pin hole size and number on the breaking strength of the adult equine radius when loaded in torsion to failure. SAMPLE POPULATION: 54 pairs of equine radii from adult horses. PROCEDURE: For test one, 12 pairs of radii were used to determine the effect of pin hole size on torsional breaking strength. A 6.35-mm hole was drilled in 1 radius, and a 9.5-mm hole was drilled in the contralateral radius. For test two, 36 pairs of radii were randomly assigned to 1 of 3 treatment groups (n = 12) to determine the effect of pin hole number on the torsional breaking strength of the equine radius. One radius of each pair served as a control, and one, three, or six 6.35-mm transcortical holes were drilled in the contralateral radius. For test three, 6 pairs of radii had torsional forces applied directly to the transfixation pins, as opposed to the bone itself. One radius of a pair served as a control, and three 6.35-mm smooth Steinman pins were placed in the contralateral radius. All radii were loaded in torsion to failure, and the breaking strengths were recorded. RESULTS: Compared with the 6.35-mm hole, the 9.5-mm hole significantly decreased torsional strength of the radius. There was no significant difference in mean torsional strength between the control radii and the radii with 1, 3, or 6 transcortical holes or when the transfixation pins were loaded. CONCLUSION: Use of up to three 6.35-mm transfixation pins can be used in a full-limb transfixation pin cast to optimize stiffness without a significant decrease (12%) in bone strength.

Animals↗
PubMed1998

Effect of three types of half-limb casts on in vitro bone strain recorded from the third metacarpal bone and proximal phalanx in equine cadaver limbs.

OBJECTIVE: To determine effect of 3 half-limb casts on bone strains recorded from the proximal phalanx (P-1) and third metacarpal bone (MCIII) of equine cadaver limbs, using a mechanical testing machine. ANIMALS: 12 equine cadaver limbs and 4 live horses. PROCEDURE: Bone strains were recorded at middorsal P-1 and the dorsal cortical aspect of the distal third of MCIII while limbs were variably loaded with 100 to 1,000 lb of force. To determine ability of the cast to protect the distal portion of the limb from weight-bearing loads, strains were recorded with the limb in 1 of the 3 casts and with it unsupported. To determine cast-induced discomfort, weight-supporting and transfixation pin casts were evaluated on 2 live horses RESULTS: All 3 casts significantly reduced bone strain at P-1. Significant differences were observed: mean 61% reduction for the standard half-limb cast, 84% for the transfixation pin cast, and 97% for the weight-supporting cast at weight-bearing force of 500 lb. Only the weight-supporting cast significantly reduced strains recorded from MCIII. The weight-supporting cast was not well tolerated by 2 live horses. CONCLUSIONS: The 3 casts significantly reduced transfer of weight-bearing forces to the distal portion of the limb. The weight-supporting cast effectively reduced strain on the P-1 to near 0, but was well tolerated by live horses. The transfixation pin cast reduced strain on the P-1 by > 80% at weight-bearing loads of 500 lb, and live horses were comfortable. Standard half-limb casts significantly reduced strains on the P-1, but to a lesser degree than did other casts.

Animals↗
PubMed1996

Laparoscopic ovariectomy in two horses with granulosa cell tumors.

Two mares were admitted for ovariectomy of unilateral granulosa cell tumors. Both mares were ovariectomized (1 unilateral and 1 bilateral) by use of a ventral abdominal laparoscopic technique. This approach required tilting the operative table 30 degrees to elevate the pelvis and to allow observation of the ovaries. Using a single laparoscopic portal and 3 to 4 instrument portals, a triangulation technique was used. The ovarian pedicles were isolated and secured via loop ligation. The ovaries then were divided from the ligated pedicle and placed within specimen bags for extraction. The specimen bags then were removed through a ventral midline celiotomy. Using this technique, it was determined that granulosa cell tumors or ovaries of up to 20 cm in diameter can be removed. Laparoscopic ovariectomy provided a means to provide tension-free dissection and ligation of the ovarian pedicle. In comparison to conventional techniques, this may improve suture security and reduce complications related to excessive pedicle tension. Improved observation during surgery, less pedicle tension, and minimal invasiveness made laparoscopic ovariectomy of these 2 mares advantageous.

Animals↗
PubMed1992

An outbreak of blue-eared pig disease (porcine reproductive and respiratory syndrome) in four pig herds in Great Britain.

The clinical syndrome of a new disease of pigs in four herds in the Humberside area is described. The first signs of the disease were anorexia, lethargy and pyrexia with up to 60 per cent of the dry sows affected. These signs were followed by an increased incidence of abortions which occurred in up to 3.3 per cent of sows, premature farrowings in up to 20.6 per cent of sows and stillbirths and late mummification which affected up to 26.0 and 18.8 per cent of fetuses, respectively. Mortality in neonatal and pre-weaning pigs reached up to 88 per cent and respiratory disease of high morbidity and low mortality occurred in fattening pigs. There were infertility problems in sows, with an increase in returns to service and a failure to show oestrus after weaning or aborting. The signs of the disease in boars were anorexia and malaise. Cyanosis of the extremities affected up to 2 per cent of the animals. The outbreak lasted 11 weeks in all the herds.

Abortion, Veterinary↗
PubMed1989

Persistence of S. typhimurium in a large dairy herd.

Salmonella typhimurium 49a infection in a large dairy herd persisted for 3.5 years. Illness initially occurred in cows and calves but latterly although there were fewer clinical cases milk filters were culturally positive on 26 out of 73 samplings. Three associated human disease incidents occurred. Individual milk samples identified one cow as an excreter and the organism was recovered from the mammary gland of this animal at slaughter. Correlation between calving pattern, the times of calving and the occurrence of positive milk filters suggest that the cow may have been excreting the organism intermittently from the udder for 2.5 years.

Animals↗
PubMed1985

Kyphosis in Jersey calves.

A condition of Jersey calves involving kyphosis and lordosis is described. Four calves originating from three farms, all the progeny of one bull, were necropsied. The only significant finding was a myopathy mainly affecting sublumbar muscles. The lesions were not consistent with white muscle disease or of any known myopathy affecting Jersey calves. It is likely that this condition represents a primary muscular dystrophy of genetic origin.

Animals↗