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.

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.

Corrective osteotomy and partial tarsal arthrodesis in two greyhounds with calcaneal malunion.

OBJECTIVE: To describe the clinical presentation and outcome of two greyhounds with calcaneal malunions that were treated with corrective osteotomy and partial tarsal arthrodesis. STUDY DESIGN: Short case series. ANIMALS: Two adult racing greyhounds. METHODS: Varus and recurvatum deformity of the calcaneus was ascribed to malunion of prior calcaneal fracture with concomitant central bone fracture that had been sustained during racing in both dogs. Both dogs exhibited severe, weight-bearing lameness and had radiographic evidence of moderate to severe osteoarthritis of the proximal intertarsal joint. A closing wedge corrective osteotomy and partial tarsal arthrodesis were performed with a 2.7-mm locking compression plate and cancellous autograft. RESULTS: Calcaneal morphology and alignment of the common calcaneal tendon seemed restored postoperatively. The implant was removed in one dog, while the other dog experienced no postoperative complications. Lameness improved in both dogs, although residual intermittent lameness after heavy exercise was reported by owners of both dogs 1 year after surgery. Overall, owner satisfaction and outcome were considered good-to-excellent in both dogs. CONCLUSION: Corrective osteotomy and partial tarsal arthrodesis for treatment of malunited calcaneal fractures may be considered in dogs with clinical signs related to calcaneal malunion.

In Vitro Biomechanical Comparison of Four Different Ventral Surgical Procedures on the Canine Fourth-Fifth Cervical Vertebral Motion Unit.

INTRODUCTION: Biomechanical properties of four different ventral surgical procedures at the canine fourth-fifth cervical (C4-C5) vertebral motion unit (VMU) were assessed and compared with the intact C4-C5 VMU. MATERIALS AND METHODS: The third-sixth cervical vertebral column from 24 skeletally mature Beagle cadavers were randomly allocated to four groups (standard ventral slot, slanted slot, inverted cone slot and intervertebral disc fenestration). Standardized tests were performed for each specimen in flexion/extension, lateral bending and axial rotation. The specimens were tested intact and after completion of one of the three slots techniques or fenestration. Pre-testing, cadaver specimens were confirmed to be free of disease by computed tomography (CT) examination. Post-testing, dimensions of slots and fenestration were determined based on a second CT examination. RESULTS: All ventral surgical procedures increased range of motion (ROM) at the C4-C5 VMU compared with intact specimens. The only significant difference in the increase in ROM was observed between slanted slot and fenestration in flexion/extension. The standard ventral slot had a significant higher increase in ROM in extension compared with the other three techniques. The slanted slot had a significant lower increase in ROM in flexion. DISCUSSION/CONCLUSION: The described ventral slot techniques have similar biomechanical effects on the canine cervical vertebral column. In contrast to the findings of a previous study, the slanted slot and inverted cone slot do not appear to provide a biomechanical benefit compared with standard ventral slot.

Minimally Invasive Spine Surgery in Small Animals.

Minimally invasive spine surgery (MISS) seems to have many benefits for human patients and is currently used for various minor and major spine procedures. For MISS, a change in access strategy to the target location is necessary and it requires intraoperative imaging, special instrumentation, and magnification. Few veterinary studies have evaluated MISS for canine patients for spinal decompression procedures. This article discusses the general requirements for MISS and how these can be applied to veterinary spinal surgery. The current veterinary MISS literature is reviewed and suggestions are made on how to apply MISS to different spinal locations.

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

OBJECTIVES: 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). METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Magnetic resonance imaging susceptibility artifacts in the cervical vertebrae and spinal cord related to monocortical screw-polymethylmethacrylate implants in canine cadavers.

OBJECTIVE To characterize and compare MRI susceptibility artifacts related to titanium and stainless steel monocortical screws in the cervical vertebrae and spinal cord of canine cadavers. SAMPLE 12 canine cadavers. PROCEDURES Cervical vertebrae (C4 and C5) were surgically stabilized with titanium or stainless steel monocortical screws and polymethylmethacrylate. Routine T1-weighted, T2-weighted, and short tau inversion recovery sequences were performed at 3.0 T. Magnetic susceptibility artifacts in 20 regions of interest (ROIs) across 4 contiguous vertebrae (C3 through C6) were scored by use of an established scoring system. RESULTS Artifact scores for stainless steel screws were significantly greater than scores for titanium screws at 18 of 20 ROIs. Artifact scores for titanium screws were significantly higher for spinal cord ROIs within the implanted vertebrae. Artifact scores for stainless steel screws at C3 were significantly less than at the other 3 cervical vertebrae. CONCLUSIONS AND CLINICAL RELEVANCE Evaluation of routine MRI sequences obtained at 3.0 T revealed that susceptibility artifacts related to titanium monocortical screws were considered mild and should not hinder the overall clinical assessment of the cervical vertebrae and spinal cord. However, mild focal artifacts may obscure small portions of the spinal cord or intervertebral discs immediately adjacent to titanium screws. Severe artifacts related to stainless steel screws were more likely to result in routine MRI sequences being nondiagnostic; however, artifacts may be mitigated by implant positioning.

Comparison of complication rates of unilateral, staged bilateral, and single-session bilateral surgery for the treatment of bilateral medial patellar luxation in dogs.

This retrospective study compared complication rates in 93 client-owned dogs (119 stifles) undergoing single-session bilateral, staged bilateral, or unilateral surgery for bilateral medial patellar luxation. Clinical characteristics and complication rates were compared and risk factors for major complications were explored. Sixty-five dogs had unilateral, 16 staged bilateral and 11 single-session bilateral surgery. Complications occurred in 28/119 stifles (24%), 11 (9%) of which required revision surgery. Patellar reluxation occurred in 7/119 (6%) stifles, with no revision required. There was no significant association between timing of surgery and incidence of complications. In dogs < 10 kg with bilateral medial patellar luxation, single-session bilateral surgery is a feasible treatment option with a complication rate comparable to staged bilateral or unilateral medial patellar luxation surgery.

Comparaison des taux de complication de la chirurgie unilatérale, bilatérale à étage, et bilatérale à session unique pour le traitement de la luxation patellaire chez le chien. Cette étude rétrospective a comparé les taux de complications observés chez 93 chiens de propriétaires (119 genoux) subissant une chirurgie bilatérale simultanée, une chirurgie bilatérale en deux temps ou une chirurgie unilatérale pour luxation médiale de la rotule bilatérale. Les données cliniques et les taux de complications ont été comparés et les facteurs à risque de complications majeures ont été étudiés. 65 chiens ont subi un traitement unilatéral, 16 un traitement bilatéral en deux temps et 11 un traitement bilatéral simultané. Des complications sont survenues dans 28/119 grassets (24 %), dont 11 (9 %) ont nécessité une chirurgie de révision. Une reluxation de la rotule s'est produite dans 7/119 grassets (6 %), sans qu'une révision n'ait été nécessaire. Aucune association significative entre le planning chirurgical et l'apparition de complications n'a pu être mise en évidence. Chez les chiens < 10 kg souffrant de luxation médiale de la rotule bilatérale, une chirurgie bilatérale simultanée est une option thérapeutique valable, possédant un taux de complications comparable à celui de la chirurgie en deux temps ou seulement unilatérale.(Traduit par les auteurs).

Biomechanical Comparison of 2 Veterinary Locking Plates to Monocortical Screw/Polymethylmethacrylate Fixation in Canine Cadaveric Cervical Vertebral Column.

OBJECTIVE: To compare the biomechanical properties of 2 veterinary locking plates and monocortical screws/polymethylmethacrylate (PMMA) fixation in canine cadaveric cervical vertebral columns. STUDY DESIGN: Biomechanical cadaveric study. MATERIALS: Nineteen cervical vertebral columns (C2-C7) from large breed, skeletally mature, canine cadavers were used. A cortical ring was placed as a disk spacer at C4-C5 in all specimens. Seven vertebral columns were plated at C4-C5 with two 4-hole, 3.5 mm string of pearls plates (SOP) and 6 vertebral columns were plated with two 6-hole, 2.4 mm titanium locking reconstruction plates (Ti recon plate). All screws were placed monocortically. Six vertebral columns had monocortical titanium screws and PMMA (Ti screws/PMMA) placed, tested as part of a prior study. METHODS: Stiffness testing in 3 directions was performed of the unaltered C4-C5 vertebral motion unit and repeated after placement of the disk spacer and implants. Data were compared using a linear mixed model that incorporated data from previously tested spines (Ti screw/PMMA). RESULTS: The mean (95% CI) stiffness (N/m) in extension for SOP was 407 N/mm (330-503), for Ti recon plate was 284 N/mm (198-407) and for Ti screws/PMMA was 365 N/mm (314-428); in flexion for SOP was 250 N/mm (178-354), for Ti recon plate was 147 N/mm (106-204) and for Ti screws/PMMA was 311 (235-416); in lateral bending for SOP was 528 N/mm (441-633), for Ti recon plate was 633 N/mm (545-735) and for Ti screws/PMMA was 327 N/mm (257-412). There were no significant differences in stiffness between the 3 fixations for any outcome. CONCLUSION: Monocortical fixation with two 3.5 mm SOP or two 2.4 mm Ti recon plates may be an alternate fixation to monocortical screws and PMMA.

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.

Evaluation of a Single Intra-Articular Injection of Autologous Protein Solution for Treatment of Osteoarthritis in a Canine Population.

OBJECTIVE: To evaluate the safety and efficacy of an intra-articular injection of autologous protein solution (APS) for treatment of canine osteoarthritis (OA). STUDY DESIGN: Prospective, randomized, blinded, placebo-controlled pilot clinical trial. ANIMALS: Client-owned dogs with single limb lameness because of OA in a stifle or elbow joint (n=21). METHODS: Lame dogs, confirmed with OA by physical and lameness examination and imaging, were randomly assigned to control or treatment groups. Owners, blinded to treatment, scored pain (University of Pennsylvania Canine Brief Pain Inventory) and lameness severity (Hudson Visual Analogue Scale [HVAS]). Weight-bearing was assessed by kinetic gait analysis. Dogs were injected intra-articularly with APS (treatment group) or saline solution (control group). Evaluations were performed before injection, and 2 and 12 weeks post-injection. RESULTS: Compared to pretreatment values, APS treatment data showed a significant improvement in week 12 pain scores (improved 25.6% over baseline), lameness scores (improved 15% over baseline) and peak vertical force (PVF; N/kg; increased 14.9% of baseline), as well as vertical impulse (Ns/kg) and PVF normalized to stance time (N/kg/s). Control group dogs improved at week 2 in owner assigned indices, but not force plate values and had no significant improvement in scores or force plate values from pretreatment values at 12 weeks. CONCLUSION: APS injection reduced pain and lameness scores and increased weight-bearing associated with the OA-affected joint in dogs at 12 weeks providing preliminary evidence that APS therapy may be beneficial in the treatment of OA in dogs and supporting pursuit of additional studies.

Surgical Treatment of Traumatic Myositis Ossificans of the Extensor Carpi Radialis Muscle in a Dog.

OBJECTIVES: To report clinical signs, diagnostic imaging findings, and outcome in a dog with traumatic myositis ossificans of the origin of the extensor carpi radialis muscle. STUDY DESIGN: Clinical report. ANIMALS: An 8-month-old intact female Irish Setter Dog. METHODS: After radiographic and computed tomographic evaluation of an osseous proliferation arising from the cranial cortex of the right distal humeral diaphysis, the protruding bone was surgically removed and evaluated by histopathology. RESULTS: Traumatic myositis ossificans was successfully treated with surgical removal of the osseous proliferation resulting in improved postoperative range of motion of the right elbow joint. There was no evidence of lameness or abnormal bone regrowth associated with the surgical site radiographically at follow up. CONCLUSION: Surgical removal of a traumatic myositis ossificans lesion resulted in full return to function in a young, competitive show dog.

Effect of an intervertebral disk spacer on stiffness after monocortical screw/polymethylmethacrylate fixation in simulated and cadaveric canine cervical vertebral columns.

OBJECTIVE: To determine the biomechanical effect of an intervertebral spacer on construct stiffness in a PVC model and cadaveric canine cervical vertebral columns stabilized with monocortical screws/polymethylmethacrylate (PMMA). STUDY DESIGN: Biomechanical study. SAMPLE POPULATION: PVC pipe; cadaveric canine vertebral columns. METHODS: PVC model-PVC pipe was used to create a gap model mimicking vertebral endplate orientation and disk space width of large-breed canine cervical vertebrae; 6 models had a 4-mm gap with no spacer (PVC group 1); 6 had a PVC pipe ring spacer filling the gap (PCV group 2). Animals-large breed cadaveric canine cervical vertebral columns (C2-C7) from skeletally mature dogs without (cadaveric group 1, n = 6, historical data) and with an intervertebral disk spacer (cadaveric group 2, n = 6) were used. All PVC models and cadaver specimens were instrumented with monocortical titanium screws/PMMA. Stiffness of the 2 PVC groups was compared in extension, flexion, and lateral bending using non-destructive 4-point bend testing. Stiffness testing in all 3 directions was performed of the unaltered C4-C5 vertebral motion unit in cadaveric spines and repeated after placement of an intervertebral cortical allograft ring and instrumentation. Data were compared using a linear mixed model approach that also incorporated data from previously tested spines with the same screw/PMMA construct but without disk spacer (cadaveric group 1). RESULTS: Addition of a spacer increased construct stiffness in both the PVC model (P < .001) and cadaveric vertebral columns (P < .001) compared to fixation without a spacer. CONCLUSIONS: Addition of an intervertebral spacer significantly increased construct stiffness of monocortical screw/PMMA fixation.

Biomechanical comparison between bicortical pin and monocortical screw/polymethylmethacrylate constructs in the cadaveric canine cervical vertebral column.

OBJECTIVE: To compare biomechanical stiffness of cadaveric canine cervical spine constructs stabilized with bicortical stainless steel pins and polymethylmethacrylate (PMMA), monocortical stainless steel screws with PMMA, or monocortical titanium screws with PMMA. STUDY DESIGN: Biomechanical cadaver study. ANIMALS: Eighteen canine cervical vertebral columns (C2-C7) were collected from skeletally mature dogs (weighing 22-32 kg). METHODS: Specimens were radiographed and examined by dual energy X-ray absorptiometry. Stiffness of the unaltered C4-C5 intervertebral motion unit was measured in extension, flexion and lateral bending using non-destructive 4-point bend testing. Specimens were then stabilized by (1) bicortical stainless steel pins/PMMA, (2) monocortical stainless steel screws/PMMA, or (3) monocortical titanium screws/PMMA. Mechanical testing was repeated and stiffness data from unaltered specimens and the 3 treatment groups were compared. RESULTS: All 3 surgical methods significantly increased stiffness of the C4-C5 motion unit compared with the unaltered specimen (P < .001 for all treatments), but stiffness was not significantly different among the 3 fixation groups (P = .578). CONCLUSIONS: In this model, monocortical screw fixation (with stainless steel or titanium screws) was biomechanically equivalent to bicortical fixation.

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.

Early reherniation of disk material in eleven dogs with surgically treated thoracolumbar intervertebral disk extrusion.

OBJECTIVE: To report findings and outcomes of dogs with reherniation of nuclear material within 7 days of hemilaminectomy for acute thoracolumbar (TL) intervertebral disk extrusion. STUDY DESIGN: Retrospective case series. ANIMALS: Chondrodystrophic dogs (n = 11). METHODS: Dogs with acute neurologic decline within 1 week of surgical decompression for TL disk extrusion were identified. Advanced imaging was used to document extradural spinal cord compression at the previous surgery site. Ten dogs had a 2nd decompressive surgery to remove extruded nuclear material. RESULTS: All dogs had acute neurologic deterioration (average, 2 neurologic grades) 2-7 days after initial hemilaminectomy. Computed tomography (CT; n = 10) or myelography (n = 1) documented extradural spinal cord compression compatible with extruded disk material at the previous hemilaminectomy site. Dogs that had a 2nd surgical decompression improved neurologically within 24 hours and were paraparetic at discharge. The single dog that did not have decompressive surgery did not regain deep nociception during 185-day follow-up. CONCLUSIONS: Early reherniation at the site of previous hemilaminectomy can produce acute deterioration of neurologic function and should be investigated with diagnostic imaging. Repeat decompressive surgery can lead to functional recovery.

Gastroesophageal intussusception in a leopard (Panthera pardus).

An 8-yr-old male leopard (Panthera pardus) was presented with a 4-day history of lethargy, vomiting, and anorexia. Thoracic and abdominal radiographs revealed a soft-tissue mass cranial to the diaphragm and atypical appearance of the gastric fundus. Esophagoscopy revealed gastric mucosa in the lumen of the esophagus, which confirmed gastroesophageal intussusception. An exploratory celiotomy with manual reduction of the intussusception was performed. Reduction was verified by intraoperative esophagoscopy and gastroscopy. An incisional fundic gastropexy to the left abdominal wall was performed to reduce the chance of a recurrence of the intussusception. No postoperative complications related to the surgery were observed, and the animal resumed eating within 48 hr of surgery. A subsequent recurrence of clinical signs was not noted by the owner.

Esophageal hiatal hernia in three exotic felines--Lynx lynx, Puma concolore, Panthera leo.

Hiatal hernia was diagnosed in three exotic felines-lynx (Lynx lynx), cougar (Puma concolore), and lion (Panthera leo). All cats had a history of anorexia. Thoracic and abdominal radiographs showed evidence of a soft tissue mass within the caudal mediastinum suggestive of a hiatal hernia in all animals. A barium esophagram was performed in one case. All animals underwent thoracic or abdominal surgery for hernia reduction. Surgical procedures included: intercostal thoracotomy with herniorrhaphy and esophagopexy (lynx and cougar), and incisional gastropexy (lion). Concurrent surgical procedures performed were gastrotomy for gastric foreign body removal and jejunostomy tube placement. Clinical signs related to the hiatal hernia disappeared after surgery and recurrence of signs was not reported for the time of follow-up.

Accuracy of conventional radiography and computed tomography in predicting implant position in relation to the vertebral canal in dogs.

OBJECTIVE: To compare the accuracy of radiography and computed tomography (CT) in predicting implant position in relation to the vertebral canal in the cervical and thoracolumbar vertebral column. STUDY DESIGN: In vitro imaging and anatomic study. ANIMALS: Medium-sized canine cadaver vertebral columns (n=12). METHODS: Steinmann pins were inserted into cervical and thoracolumbar vertebrae based on established landmarks but without predetermination of vertebral canal violation. Radiographs and CT images were obtained and evaluated by 6 individuals. A random subset of pins was evaluated for ability to distinguish left from right pins on radiographs. The ability to correctly identify vertebral canal penetration for all pins was assessed both on radiographs and CT. Spines were then anatomically prepared and visual examination of pin penetration into the canal served as the gold standard. RESULTS: Left/right accuracy was 93.1%. Overall sensitivity of radiographs and CT to detect vertebral canal penetration by an implant were significantly different and estimated as 50.7% and 93.4%, respectively (P<.0001). Sensitivity was significantly higher for complete versus partial penetration and for radiologists compared with nonradiologists for both imaging modalities. Overall specificity of radiographs and CT to detect vertebral canal penetration was 82.9% and 86.4%, respectively (P=.049). CONCLUSIONS: CT was superior to radiographic assessment and is the recommended imaging modality to assess penetration into the vertebral canal. CLINICAL RELEVANCE: CT is significantly more accurate in identifying vertebral canal violation by Steinmann pins and should be performed postoperatively to assess implant position.

Description and repeatability of a newly developed spinal cord injury scale for dogs.

The objectives of this study were to describe a new spinal cord injury scale for dogs, evaluate repeatability through determining inter-rater variability of scores, compare these scores to another established system (a modified Frankel scale), and determine if the modified Frankel scale and the newly developed scale were useful as prognostic indicators for return to ambulation. A group of client-owned dogs with spinal cord injury were examined by 2 independent observers who applied the new Texas Spinal Cord Injury Score (TSCIS) and a modified Frankel scale that has been used previously. The newly developed scale was designed to describe gait, postural reactions and nociception in each limb. Weighted kappa statistics were utilized to determine inter-rater variability for the modified Frankel scale and individual components of the TSCIS. Comparisons were made between raters for the overall TSCIS score and between scales using Spearman's rho. An additional group of dogs with surgically treated thoracolumbar disk herniation was enrolled to look at correlation of both scores with spinal cord signal characteristics on magnetic resonance imaging (MRI) and ambulatory outcome at discharge. The actual agreement between raters for the modified Frankel scale was 88%, with a weighted kappa value of 0.93. The TSCIS had weighted kappa scores for gait, proprioceptive positioning and nociception components that ranged from 0.72 to 0.94. Correlation between raters for the overall TSCIS score was Spearman's rho=0.99 (P<0.001). Comparison of the overall TSCIS score to the modified Frankel score resulted in a Spearman's rho value of 0.90 (P<0.001). The modified Frankel score was weakly correlated with the length of hyperintensity of the spinal cord: L2 vertebral body length ratio on mid-sagittal T2-weighted MRI (Spearman's rho=-0.45, P=0.042) as was the overall TSCIS score (Spearman's rho=-0.47, P=0.037). There was also a significant difference in admitting modified Frankel scores (P=0.029) and admitting overall TSCIS scores (P=0.02) between dogs that were ambulatory at discharge and those that were not. Results from this study suggest that the TSCIS is an easy to administer scale for evaluating canine spinal cord injury based on the standard neurological exam and correlates well with a previously described modified Frankel scale.