Accuracy of end-on fluoroscopy in predicting implant position in relation to the vertebral canal in dogs.

Objective To evaluate the accuracy of end-on fluoroscopy in predicting implant position in relation to the vertebral canal in the canine thoracolumbar vertebral column. Study design In vitro imaging and anatomic study. Animals Canine cadaveric thoracolumbar vertebral columns (n = 5). Methods Smooth Steinmann pins were inserted bicortically into the thoracolumbar vertebral columns between T10 and L7 using recommended insertion angles. Penetration of the spinal canal was not strictly avoided. After pin placement, end-on fluoroscopy images were obtained of each pin. Pin position was subsequently assessed by four evaluators and determined to either being out of the vertebral canal or in, with the latter being additionally divided into partially or completely penetrating the canal. To assess potential differences in modalities, fluoroscopy images were gray-scale inverted and evaluated again later by the same four individuals. Correct identification of pin position in relationship to the vertebral canal was assessed for both fluoroscopy images. Anatomic preparation of the spines was used for verification of pin position in relation to the spinal canal. Some data from this study were compared with historical data on accuracy using orthogonal radiography and computed tomography (CT). Results Overall sensitivity and specificity of F to detect vertebral canal penetration was 98.8 % (95% confidence interval (CI), 96.0-99.6) and 98.0% (95% CI, 77.0-99.9), respectively. For Fi, sensitivity and specificity were 97.0% (95% CI, 91.5-99.0) and 98.5% (95% CI, 81.5-99.9) respectively. F exceeded Fi for the sensitivity of detecting pin penetration into the vertebral canal (p = 0.039) but specificities were not different (p = 0.585). When comparing to historical data, the overall accuracy of end-on fluoroscopy (F) and inverted fluoroscopy (Fi) was statistical better than conventional radiographic assessment (p < 0.001). Conclusion End-on fluoroscopy is a highly accurate method for the assessment of pin position in relationship to the thoracolumbar spinal canal in cadaveric dogs. Clinical significance End-on fluoroscopy, with or without inversion, is accurate in identifying vertebral canal violation by bicortically placed Steinmann pins. When CT is not available, end-on fluoroscopy might be a valuable imaging modality to determine pin position in the canine vertebral column

MONTEGGIA LESION IN AN ASIAN SMALL-CLAWED OTTER ( AONYX CINEREA

A 10-yr-old female Asian small-clawed otter (Aonyx cinerea) presented with a history of right forelimb lameness. Antebrachial radiographs revealed a Monteggia lesion, classified by cranial radial head luxation and distal diaphyseal ulnar fracture. Open reduction with placement of an ulnar-radial positional screw was performed. The lateral collateral ligament was reconstructed using suture anchored by a condylar screw and bone tunnel in the radius. Reduction and proper implant placement was confirmed on postoperative radiographs. The ulnar-radial positional screw was removed 6 wk postoperatively to allow proper supination and pronation. Limb function was greatly improved at this time; however, a mild lameness was still observed. At 7 mo postoperatively, the otter was ambulating lameness-free. Radiographs documented proper joint reduction and stable condylar screw. At 32 mo postoperatively, the otter continued to exhibit normal ambulation

Biomechanical comparison of screw and suture fixation for temporary transarticular tarsocrural immobilization in canine cadavers.

Objective: To biomechanically evaluate an ultrahigh-molecular-weight polyethylene (UWMWPE) suture for temporary tarsocrural immobilization as a potential alternative to the existing surgical method, which uses a 4.5 AO/ASIF calcaneotibial cortical screw. Study design: Randomized in vitro biomechanical study. Animals: Pelvic limbs (n = 20) from 10 euthanized adult dogs (average bodyweight of 29.9 kg ± 1.9 kg). Methods: Tarsocrural joints were immobilized either with a 4.5 AO/ASIF screw or a 1 mm diameter UHMWPE suture. Limbs were loaded with 60 N, 120 N, and 180 N, each for 100 cycles. After cyclic loading, immobilizations were loaded until failure. Load at failure and mode of failure were recorded. Results: Both immobilization methods remained intact during loading with 60 N, 120 N, and 180 N. Mean and standard deviation (± SD) failure loads were higher for the cortical screw (524.9 N ± 148.7 N) than for the UHMWPE suture (387.8 N ± 105.6 N), P = .0084. The stiffness of both systems was equivalent. Conclusion: Both techniques were suitable for transarticular tarsocrural immobilization in large-breed canine cadavers. While load at failure was higher for the screw compared to the suture construct, stiffness of both methods was comparable based on the laboratory settings in this in vitro study. Clinical significance: Based on the results of this study, both the cortical screw and the UHMWPE suture stabilized the tibiotarsal joint at clinically relevant loads. However, when exposed to high loads, the cortical screw provides increased tibiotarsal stability. Comparative data need to be collected prior to widespread use of UHMWPE sutures in clinical cases

Comparison of harmonic blade versus traditional approach in canine patients undergoing spinal decompressive surgery for naturally occurring thoracolumbar disk extrusion

<div><p>Objectives</p><p>To assess feasibility of the harmonic Osteovue blade (HOB) for use in the soft tissue approach for dogs undergoing hemilaminectomy and to compare outcomes between dogs undergoing HOB or traditional approach (TRAD).</p><p>Methods</p><p>A prospective randomized clinical trial was performed using 20 client-owned dogs with thoracolumbar intervertebral disk extrusion requiring hemilaminectomy. Dogs were randomly assigned to HOB or TRAD. Neurologic function and pain scores were assessed pre-operatively. Intraoperative blood loss and surgical approach time as well as postoperative pain and wound healing scores were recorded. Additionally, neurologic recovery and owner perceived quality of life were recorded at day 10 and 30 postoperative.</p><p>Results</p><p>There was no significant difference in sex distribution, weight, age, preoperative neurological grade and pain score, and perioperative outcome measures between groups. Intraoperative total blood loss was minimal for HOB and TRAD (median: 0 ml (range 0–9) and 2.2 ml (range 0–6.8), respectively; p = 0.165) and approach times were similar (median: 7 min (range 5–12) and 8 min (range 5–13), respectively; p = 0.315). While changes in wound healing scores were similar, changes in postoperative pain scores and neurological function were significantly improved in the HOB compared to the TRAD group. Postoperative complications in the HOB group consisted of automutilation of part of the incision and development of a small soft, non-painful subcutaneous swelling in 1 dog each.</p><p>Conclusions</p><p>The HOB is a safe and effective tool for the soft tissue approach for routine spinal surgery in dogs and is associated with decreased pain and increased neurological function post-surgery.</p></div

Evaluation of Three Human Cervical Fusion Implants for Use in the Canine Cervical Vertebral Column.

OBJECTIVE: To assess technical feasibility and mechanical properties of 3 locking plate designs (Zero-P, Zero-P VA, and Uniplate 2) for use in the canine cervical spine. STUDY DESIGN: Prospective ex vivo study. ANIMALS: Cadaver cervical spines from skeletally mature large breed dogs (n = 18). METHODS: Specimens were screened using radiography and allocated into balanced groups based on bone density. Stiffness of intact C4-C5 vertebral motion units was measured in extension, flexion, and lateral bending using nondestructive 4-point bend testing. Uniplate 2 was then implanted at C4-C5 and mechanical testing was repeated. Mechanical test data were compared against those from 6 spines implanted with monocortical screws, an allograft ring spacer, and PMMA. RESULTS: The Zero-P and Zero-P VA systems could not be surgically implanted due to anatomical constraints in the vertebral column sizes of the canine cervical spines used in this study. Fixation with Uniplate 2 or with screws/PMMA significantly increased stiffness of the C4-C5 vertebral motion units compared to unaltered specimens (P < .001) in extension. Stiffness of the titanium screw/PMMA fixation was significantly greater than the Uniplate 2 construct in extension. Flexion and lateral bending could not be evaluated in 3 of 6 specimens in the Uniplate 2 group due to failure at the bone/implant interface during extension testing. CONCLUSION: Fixation with Uniplate 2 was biomechanically inferior to screws/PMMA. Particularly concerning was the incidence of vertebral fracture after several testing cycles. Based on our results, Zero-P, Zero-P VA, and Uniplate 2 cannot be recommended for use in dogs requiring cervical fusion.College of Veterinary Medicine, The Ohio State University (intramural award)This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1111/vsu.1253

Comparison of various <i>preoperative</i> factors between dogs undergoing thoracolumbar spinal decompressive surgery for intervertebral disk extrusion selected for Harmonic Osteovue Blade (HOB; n = 10) versus traditional surgical approach (TRAD; n = 10).

<p>Comparison of various <i>preoperative</i> factors between dogs undergoing thoracolumbar spinal decompressive surgery for intervertebral disk extrusion selected for Harmonic Osteovue Blade (HOB; n = 10) versus traditional surgical approach (TRAD; n = 10).</p

Harmonic Osteovue blade set-up.

<p>A: photographs of the generator, foot switch and hand piece (Ethicon Endo-Surgery, Inc.). B: photographs of the harmonic Osteovue blade (Ethicon Endo-Surgery, Inc.) showing the spade-like and curved shape of the blade tip.</p

Quantitative comparisons of various <i>perioperative</i> factors between dogs undergoing thoracolumbar spinal decompressive surgery for intervertebral disk extrusion using either Harmonic Osteovue Blade (HOB; n = 10) or traditional surgical approach (TRAD; n = 10).

<p>Quantitative comparisons of various <i>perioperative</i> factors between dogs undergoing thoracolumbar spinal decompressive surgery for intervertebral disk extrusion using either Harmonic Osteovue Blade (HOB; n = 10) or traditional surgical approach (TRAD; n = 10).</p

Qualitative comparisons of various <i>postoperative</i> factors between dogs undergoing thoracolumbar spinal decompressive surgery for intervertebral disk extrusion using either Harmonic Osteovue Blade (HOB; n = 10) or traditional surgical approach (TRAD; n = 10).

<p>Qualitative comparisons of various <i>postoperative</i> factors between dogs undergoing thoracolumbar spinal decompressive surgery for intervertebral disk extrusion using either Harmonic Osteovue Blade (HOB; n = 10) or traditional surgical approach (TRAD; n = 10).</p