Search Results

You are looking at 1 - 10 of 10 items for

  • Author or Editor: Karl H. Kraus x
  • Refine by Access: All Content x
Clear All Modify Search
in Journal of the American Veterinary Medical Association

SUMMARY

Evoked potentials were induced by transcranial stimulation and recovered from the spinal cord, and the radial and sciatic nerves in six dogs. Stimulation was accomplished with an anode placed on the skin over the area of the motor cortex. Evoked potentials were recovered from the thoracic and lumbar spinal cord by electrodes placed transcutaneously in the ligamentum flavum. Evoked potentials were recovered from the radial and sciatic nerves by surgical exposure and electrodes placed in the perineurium. Signals from 100 repetitive stimuli were averaged and analyzed. Waveforms were analyzed for amplitude and latency. Conduction velocities were estimated from wave latencies and distance traveled. The technique allowed recovery of evoked potentials that had similar characteristics among all dogs. Conduction velocities of potentials recovered from the radial and sciatic nerves suggested stimulation of motor pathways; however, the exact origin and pathway of these waves is unknown.

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

SUMMARY

A 3.5-mm cortical orthopedic screw was compared with a 4.0-mm cancellous screw for maximal load to failure in the pelvis of immature dogs. The pelvis from young cadavers (7 to 13 months old) was divided into hemipelves and used for testing of the 2 screw types. Two sites in each hemipelvis were used, mid-shaft of the ilium and mid-sacrum, including the wing of the ilium. The screws were extracted, and maximal load to failure and mode of failure were recorded. Maximal load to failure per millimeter of engaged thread was calculated. In either pelvic site, the 4.0-mm cancellous screw required a significantly (P < 0.05) higher pullout force per millimeter of engaged screw threads than did the 3.5-mm cortical bone screw.

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To compare suture placement time, tension at skin separation and suture line failure, and mode of failure among 4 suture patterns.

DESIGN Randomized trial.

SAMPLE 60 skin specimens from the pelvic limbs of 30 purpose-bred Beagles.

PROCEDURES Skin specimens were harvested within 2 hours after euthanasia and tested within 6 hours after harvest. An 8-cm incision was made in each specimen and sutured with 1 of 4 randomly assigned suture patterns (simple interrupted, cruciate, intradermal, or subdermal). Suture placement time and percentage of skin apposition were evaluated. Specimens were mounted in a calibrated material testing machine and distracted until suture line failure. Tensile strength at skin-edge separation and suture-line failure and mode of failure were compared among the 4 patterns.

RESULTS Mean suture placement time for the cruciate pattern was significantly less than that for other patterns. Percentage of skin apposition did not differ among the 4 patterns. Mean tensile strength at skin-edge separation and suture-line failure for the simple interrupted and cruciate patterns were significantly higher than those for the intradermal and subdermal patterns. Mean tensile strength at skin-edge separation and suture-line failure did not differ significantly between the intradermal and subdermal patterns or the simple interrupted and cruciate patterns. The primary mode of failure for the simple interrupted pattern was suture breakage, whereas that for the cruciate, intradermal, and subdermal patterns was tissue failure.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested external skin sutures may be preferred for closure of incisions under tension to reduce risk of dehiscence.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To evaluate the efficacy of combined administration of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF-I) on the regeneration of transected and anastomosed sciatic nerves.

Animals

25 male Lewis rats.

Procedure

Transection and anastomosis was performed of the left sciatic nerve of all rats. At the time of surgery, treatment group rats received a combination of PDGF (0.75 μg) and IGF-I (1.5 μg) along with vehicle (2% methyl cellulose gel) at the anastomosis site. Control rats received vehicle alone. Evaluation consisted of motor evoked potentials and nerve conduction velocity, quantitative histologic examination, sciatic functional index, and visual assessment of repair organization (lesion scores).

Results

Significant differences in motor evoked potential latency, nerve conduction velocity, axon number, sciatic functional index, or lesion scores were not found between groups.

Conclusions

Combined administration of PDGF and IGF-I did not enhance peripheral nerve regeneration in a transection and anastomosis model as determined 6 weeks after surgery.

Clinical Relevance

These findings support the assumption that mechanical, versus trophic, effects predominate when nerve ends are closely apposed. (Am J Vet Res 1997;58:1033–1037)

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To investigate associations between recovery of locomotion and putative prognostic factors in dogs with loss of deep pain perception in the pelvic limbs caused by intervertebral disk herniation (IVDH).

DESIGN Prospective cohort study.

ANIMALS 78 client-owned dogs evaluated for IVDH that underwent spinal decompression surgery.

PROCEDURES Dogs with complete loss of deep pain perception in the pelvic limbs and tail underwent routine examinations, advanced imaging, and spinal decompression surgery in accordance with standards of practice and owner consent. For each dog, information was prospectively collected on duration of clinical signs prior to onset of paraplegia; delay between onset of paraplegia and initial referral evaluation; date of recovery of locomotion, death, or euthanasia (3-month follow-up period); and whether dogs had received corticosteroid drugs before surgery. Severity of spinal cord compression at the lesion epicenter was measured via CT or MRI.

RESULTS 45 of 78 (58%) of dogs recovered the ability to ambulate independently within 3 months after spinal decompression surgery. No evidence of prognostic value was identified for any of the investigated factors; importantly, a greater delay between onset of paraplegia and referral evaluation was not associated with a poorer prognosis.

CONCLUSIONS AND CLINICAL RELEVANCE In this group of dogs with IVDH, immediacy of surgical treatment had no apparent association with outcome. The prognosis for recovery may instead be strongly influenced by the precise nature of the initiating injury.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To evaluate the feasibility of endoscopic inspection of thoracolumbar and lumbar pedicle tracts in a canine large-breed model and its accuracy for the detection of breached versus nonbreached tracts.

ANIMALS

2 greyhound cadavers.

METHODS

CT scans of 2 greyhound cadavers from the sixth thoracic vertebra to the sacrum were obtained. Fifty-six pedicles were randomized to have drill tracts with different modified Zdichavsky grades (nonbreached, partial/full medial breach, or partial/full lateral breach) using 3-D–printed guides. Endoscopy was performed on a single occasion from October 9 to 10, 2023, using a 1.9-mm 0-degree needle arthroscope in a randomized blinded fashion. The grading of drill tracts was performed on postoperative CT. Specificity, sensitivity, positive and negative predictive values, and time to assign endoscopic grade were investigated.

RESULTS

Postoperative CT confirmed 43 nonbreached tracts, 7 medial breaches (partial/full), and 5 lateral breaches (partial/full). One tract was excluded because of guide misplacement. Intraosseous endoscopy was successfully performed in the remaining 55 drill tracts. Sensitivity to detect medial and lateral breaches was 71.4% and 60.0%. Negative predictive value was 93.1%. Specificity was 94.2%. Positive predictive value for detection of medial and lateral breaches was 83.3% and 54.5%. Median (range) time to assign an endoscopic grade was 118 (30 to 486) seconds.

CLINICAL RELEVANCE

Intraosseous endoscopy of pedicle drill tracts may be a useful adjunct technique during pedicle screw/pin placement in dogs.

Open access
in American Journal of Veterinary Research