George A. Henry

Radiographic development of canine hip dysplasia.

The radiographic changes observed in the development of CHD in the dog are complex and not fully understood despite years of research. Moderate to severe CHD is relatively easy to diagnose using standard radiographic views and evaluation techniques. However, early detection of mild or borderline CHD continues to be difficult to reliably detect radiographically. Efforts continue to be made to develop new views, techniques, and evaluation methods that will improve the radiographic evaluation of CHD. Until better methods are proven, the standard ventrodorsal leg extended view, evaluated by an experienced reviewer, will remain the method of choice for radiographic detection of CHD.

Determination of fetal numbers in Alpine does by real-time ultrasonography

Abstract Pregnancy diagnosis was carried out in Alpine does using a real-time ultrasound instrument equipped with a 5 MHz sector array probe. Eighty Alpine does were examined 5 and 7 wk after breeding. Does were restrained while standing, and the transducer probe was placed on the hairless caudal ventral abdominal wall cranial to the udder. Non-pregnant does were readily and accurately recognized at 5 and 7 wk after breeding. Number of fetuses per doe at 5 wk of gestation was different (P 0.2) to the number born. Accuracy for determining singles, twins, and triplets at 5 wk of gestation was 44, 73, and 67%, respectively; at 7 wk of gestation it was 82, 89 and 100%, respectively. This accuracy is similar to that reported in ewes. It was concluded that real-time ultrasonography scanning by the transabdominal route is a reliable method for early pregnancy diagnoses in goats. The technique also enables accurate separation of does carrying singles, twins, and triplets as early as 7 wk in gestation. Such information can be useful for improved nutritional management.

Use of the holmium:YAG laser for percutaneous photothermal ablation of cervical invertebral disks in dogs

Holmium:YAG laser ablation of thoracolumbar disks in dogs has been shown to be an effective alternative to standard surgical fenestration techniques. Our hypothesis was the Holmium:YAG laser could be equally effective and safe when used to ablate cervical intervertebral disks. Six normal chondrodystrophoid breed dogs were used. A sterile, cleaved, 320 micrometers , low-OH quartz optical fiber was inserted into each needle and the laser activated for 40 s at 2 W mean power and a 15 Hz pulse repetition rate for a total of 80 J. Dogs were observed in pain, neurological deficits, or other complications for 24 weeks. At 24 weeks, dogs were euthanatized and cervical disks collected and placed in 10 percent neutral buffered formalin. Disks were decalcified, sectioned at 5 micrometers , and stained with H and E. No problems were encountered during the procedure except occasional difficulties passing the needle by the shoulder to enter the C6-7 disk space. No complications, including neurologic deficits or pain were observe during the 24 weeks. Histologic examination revealed varying degrees of necrosis and defects created in the nucleus pulposus by laser irradiation. In some instances there was evidence of mild adjacent annular and bony thermal injury. On the basis of these result, the Ho:YAG laser appears to be a safe and efficacious method for ablation of canine cervical disks.

Holmium:YAG laser discectomy in dogs: a pilot project

Objectives of our project were to determine the affects of Ho:YAG laser energy on canine intervertebral (IV) discs by thermography, and histology. Multiple IV discs in three cadaveric nonchondrodystrophoid spines were treated with 20 J to 180 J of energy and evaluated by thermography and histology. Histologic evaluation revealed thermal affects at all doses including potential acoustic wave affects, increased eosinophilia, carbonization, and in some cases a large defect due to laser irradiation. Laser affects were confined only to the nucleus pulposus and annulus fibrosus with adjacent structures unaffected. In an acute study, two nonchondrodystrophoid dogs were sacrificed after IV discs were treated with 20 - 180 J of Ho:YAG laser radiation, following an extensive dorsal laminectomy to allow placement of thermoprobes in spinal and spinal cord structures. Heating occurred in only the nucleus pulposus and annulus fibrosus with minimal temperature changes in the adjacent structures including the spinal cord.