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Biomedical subjects

M A Collier

Publications and source records attributed to M A Collier.

27 records · Page 2Linked to original sources

Fatigue characteristics and biocompatability of a totally implantable bone growth stimulator in ponies.

Materials fatigue and gross biocompatability of an implantable bone growth stimulator (BGS) were assessed in a 6-month trial using 6 ponies. The forelegs of each pony were implanted with a BGS; the right leg implant had the cathode and cathode lead preconnected by the manufacturer, and the left leg implant was connected at surgery. Evaluation was by radiographic and clinical examination at the beginning and end of the experimental period. Six of the 12 cathode leads (50%) and 7 of the 12 cathodes (58%) were broken at 6 months. All of the implanted preconnected cathode and insulated cathode leads and 33.3% of the surgically connected cathodes and insulated cathode leads were connected at the titanium connector socket at 6 months. This BGS may exhibit wire fatigue greater than 50% of the time when used in the distal extremity of the horse.

Animals↗

Physitis in the horse.

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Animal Nutritional Physiological Phenomena↗

Holmium:YAG laser-assisted capsular shift in a canine model: intraarticular pressure and histologic observations.

The purpose of this study was to determine the initial effects of Holmium:YAG laser energy on the shoulder joint capsule. A new surgical procedure to correct shoulder joint instability uses Holmium:YAG laser energy to cause "shrinkage" of joint capsular tissues. To date there has been no information concerning an intraoperative measurable end point for the application of laser energy at surgery or the resultant depth and degree of tissue alteration. Seven greyhound dogs were used in this study. Preoperative intraarticular pressures (IAP) were measured on entry and after injection of 10 ml of solution. Laser energy was applied to the cranial medial glenohumeral ligament and joint capsule of all right shoulders with arthroscopic visualization. The unoperated left shoulders served as the control group. Six weeks after surgery pressure measurements were performed on both shoulders. A "second look" arthroscopy was performed on the shoulders. After euthanasia was performed, the anterior capsular tissues were harvested from both shoulders for histologic examination. The specimens were inspected by three blinded examiners. After 6 weeks the postoperative laser-treated IAP were higher than the same joint preoperative IAP in four of six dogs for both static nondistension and 10 ml distension measurements. At this same interval the marked tissue damage of the treated capsule was easily discerned by blinded observers. On histologic evaluation the laser-treated capsule showed synovitis and pericapsular tissue reactivity. The depth of the injury was beyond the joint capsule into the pericapsular tissue. It was not possible to determine the end point of the capsular "shrinkage" operation by combined pressure/volume intraoperative measurements. There was no uniform joint capsule compliance at 6 weeks. The histologic changes were extensive in both magnitude and depth. Future studies in this animal should include decreased laser energy plus other means of monitoring the intraoperative effects of laser use.

Animals↗

The effect of CO2 laser neurectomy on neuroma formation and axonal regeneration.

In an attempt to prevent neuroma formation and digital reinnervation after sharp palmar digital neurectomy in 10 adult horses with navicular disease, 18,426 W/cm2 of CO2 laser energy was applied to the proximal nerve stump. Clinical follow-up was 4 to 23 months. In two horses, palmar digital nerve biopsies were taken at month 4 (four nerves) and month 7 (two nerves). Nine horses were sound immediately and at all follow-up examinations. None had clinical evidence of painful neuroma or digital reinnervation. Histologically, there was minimal scar tissue at the surgical site; axonal sprouts were comingled with fibrous tissue.

Animals↗

An arthroscopic biopsy procedure for obtaining osteochondral samples from the equine midcarpal joint.

An in vivo biopsy technique was developed to harvest cylindrical osteochondral core samples (2 mm diameter x 2 mm depth) from the articular surfaces of radial carpal bones in adult horses for use in osteoarthritis drug kinetic studies. A 25 degree arthroscope was introduced into the midcarpal joint through the dorsolateral surface, and a custom-built motorized core drill was introduced through the dorsomedial surface to create the osteochondral core samples. A total of 24 core samples were sequentially harvested in vivo, and 16 at postmortem, from eight horses on four different occasions within a 96-h period. Cores ranged in weight, from 5.0 to 19.0 mg with a median of 13.25 mg, mostly due to the amount of subchondral bone present. No evidence of carpal bone fractures was observed associated with core sample sites at postmortem. No tissue distortion or thermal damage occurred to the osteochondral core samples. No detrimental effects on the tissue surrounding the biopsy sites was detected on microscopic examination. This technique offers a simple and effective procedure for obtaining multiple in vivo osteochondral core samples at various time intervals for cartilage or osteoarthritis research or analysis of clinical joint disease in the horse.

Animals↗