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  • Author or Editor: Pierre M. Montavon x
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Abstract

Objective—To determine the outcome of dogs and cats in which a tension band technique was used to stabilize traumatic fractures and luxations of the thoracolumbar vertebrae.

Design—Retrospective study.

Animals—38 client-owned animals (22 dogs and 16 cats) weighing between 1.4 and 45 kg (3 and 99 lb).

Procedure—Medical records of cats and dogs that underwent tension band stabilization of thoracolumbar fractures and luxations at the University of Zurich between 1993 and 2002 were reviewed. The stabilization technique was a modification of a spinal stapling technique with a figure 8 hemicerclage wire placed in a tension band fashion across the lesion. Neurologic status, lesion location and type, and concomitant traumatic injuries were assessed from the medical records and preoperative radiographs. Clinical outcome and complications were determined through follow-up examinations or telephone conversations with the owners.

Results—Complete or satisfactory neurologic recovery was achieved in 30 (79%) patients. Seven patients were euthanatized (6 owing to poor neurologic recovery and 1 owing to implant failure), and 1 dog was managed at home despite paraplegia. Clinically, only 4 patients (11%) had evidence of implant or fixation failure; all were dogs weighing > 16 kg (35 lb).

Conclusions and Clinical Relevance—Results suggest that the tension band technique may be appropriate for stabilization of fractures and luxations of the thoracolumbar vertebrae in cats and small- or medium- sized dogs. In larger dogs, fixation strength may be insufficient to stabilize certain fracture types and ancillary external or internal fixation methods may be needed. (J Am Vet Med Assoc 2004;225:78–83)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To measure the angles between the patellar ligament and the tibial plateau and between the patellar ligament and the common tangent at the tibiofemoral contact point (TFCP) throughout the full range of motion of the stifle joint in dogs and determine the flexion angles at which the patellar ligament is perpendicular to the tibial plateau or to the common tangent.

Sample Population—16 hind limbs from cadavers of 9 adult dogs without radiographically detectable degenerative joint disease.

Procedures—Mediolateral radiographic views of the stifle joints from full extension through full flexion were obtained (10° increments). Angles between the tibial and femoral long axes (β), between the patellar ligament and the tibial plateau γ), and between the patellar ligament and the common tangent at TFCP (α) were measured. Data were analyzed via simple linear regression.

Results—In canine stifle joints, angles γ and α decreased linearly with increasing flexion (angle β). The patellar ligament was perpendicular to the tibial plateau and perpendicular to the common tangent at the TFCP at 90° and 110° of flexion, respectively.

Conclusions and Clinical Relevance—By use of the conventionally defined tibial plateau, data suggest that at approximately 90° of flexion in stifle joints of dogs, shear force in the sagittal plane exerted on the proximal portion of the tibia shifts the loading from the cranial to the caudal cruciate ligament. Analyses involving the common tangent at the TFCP (a more anatomically representative reference point) identified this crossover point at approximately 110° of joint flexion.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To investigate sacroiliac luxation repair with positional screw insertion from the ventral surface of the sacral wing via a ventral abdominal approach in cats.

Animals—18 European shorthair cats.

Procedures—All cats underwent clinical examination including orthopedic and neurologic examination and assessment of lameness and pain before and immediately after surgery and 6 and 16 weeks after surgery. All sacroiliac luxations were stabilized with a single positional 2.4-mm cortical titanium self-tapping screw. The pelvic floor was also repaired in selected cats. Screw entry points and angles determined in a prior study of cadavers were used. Radiographs were taken before surgery and during follow-up evaluations to assess postoperative sacroiliac luxation reduction, implant placement, and repair stability.

Results—All implants were placed correctly. Iatrogenic sciatic nerve injuries occurred in 2 cats. Median time to ambulation was 1.5 days for cats with sacroiliac luxation as the sole injury. Radiographic outcome of sacroiliac luxation repair was excellent in 15 of 17 repairs, good in 1 of 17 repairs, and poor in 1 of 17 repairs. Clinical outcome was excellent in 11 of 15 cats and good in 4 of 15 cats.

Conclusions and Clinical Relevance—Insertion of a positional screw across the sacroiliac joint via a ventral abdominal approached can be an alternative to conventional techniques of sacroiliac luxation repair in cats. This novel technique allowed repair of bilateral sacroiliac luxation, repair of pelvic floor fractures, and treatment of soft tissue injuries of the abdominal cavity or abdominal organs with a single approach.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To investigate a technique for repair of sacroiliac luxation with positional screw insertion from the ventral surface of the sacral wing via a ventral abdominal approach.

Sample Population—Hemipelvis specimens from cadavers of 5 small- to large-breed dogs and 9 European shorthair cats.

Procedures—An optimal entry point and a safe drill corridor for implant placement were determined (4 hemipelvis specimens). Anatomic landmarks were identified, and the surgical technique for a ventral abdominal approach was described. Single positional screw placement was performed across the sacroiliac joint in 23 hemipelvis specimens. Screws were aimed at 25°(n = 2), 35° (2), and 45° (19) angles to the vertical axis in a transverse plane (α angles) and at a 90° angle to the longitudinal axis in a dorsal plane (β angle). Implant placement was assessed by radiographic evaluation of the cadavers and of the hemipelvis specimens devoid of soft tissue.

Results—By use of α angles of 35° and 45°, 20 of 21 implants were placed adequately; screws crossed the sacroiliac joint and penetrated the wing of the ilium without damaging adjacent nerves. The measured median α angle was 38°, and the median β angle was 88°. One complication was recorded.

Conclusions and Clinical Relevance—Cortical positional screw placement from the ventral aspect of the sacral wing by use of a ventral abdominal approach could be an alternative to conventional techniques. This novel technique may be useful for repair of bilateral sacroiliac luxation, treatment of concomitant soft tissue injuries of the caudal portion of the abdominal cavity or abdominal wall, and repair of pelvic floor fractures in a single approach.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate mediolateral radiographic views of stifle joints to identify conforma-tional differences between athletically sound dogs and dogs with cranial cruciate ligament disease (CCLD).

Sample Population—Radiographic images of 50 stifle joints of 43 dogs with surgically confirmed CCLD and 50 stifle joints of 38 dogs without clinical signs of stifle joint disease.

Procedures—Mediolateral radiographic views of stifle joints were obtained, and long axes of the femur, tibia, and femoral condyles were measured. Angles between long axes of the femur and femoral condyle and between long axes of the femur and tibia were measured. Circles were drawn representing the joint surface of femoral condyles (circle 1), area of contact on the tibial plateau (circle 2), and femoral trochlea (circle 3). Radii of circles 1, 2 (line F), and 3 were measured. Distances between midpoints of circles 1 and 2 (line K) and between midpoint of circle 2 and most cranial aspect of the tibial tuberosity (line G) were measured. To evaluate differences in conformation that could lead to CCLD, quotients derived from measurements were created for comparison; angles were compared between dog groups.

Results—Significant differences were found in the quotients created by the lengths of lines G and F and lines G and K between dogs with and without CCLD.

Conclusions and Clinical Relevance—No anatomic differences were detected in the distal portion of the femur between dogs with and without CCLD. Development of the tibial tuberosity and shape (convexity) of tibial condyles may be relevant in the pathogenesis of CCLD.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To measure the angles between the patellar ligament and the tibial plateau and between the patellar ligament and the common tangent at the tibiofemoral contact point (TFCP) in stifle joints of dogs with partial rupture of the cranial cruciate ligament (CrCL) for comparison with data obtained for stifle joints in dogs with intact CrCLs.

Sample Population—60 stifle joints of 54 dogs with surgically confirmed partial CrCL rupture.

Procedures—Mediolateral radiographic views of the stifle joints were obtained, and the angles between the patellar ligament and the conventionally defined tibial plateau (angle γ) and between the patellar ligament and the common tangent to the TFCP (angle α) were measured at incidental stifle joint flexion (angle β) by 2 independent observers. Data underwent linear regression analysis and were compared with findings in joints of dogs without degenerative joint disease.

Results—In stifle joints of dogs with a partial rupture of the CrCL, angles γ and α were 5° and 2° larger than each corresponding angle in healthy canine joints. At 100° of flexion, the patellar ligament was perpendicular to the conventionally defined tibial plateau. At 110° of flexion, the patellar ligament was perpendicular to the common tangent at the TFCP.

Conclusions and Clinical Relevance—In dogs, stifle joints with partially ruptured CrCLs have marginally larger angles between the patellar ligament and the tibial plateau, compared with joints with intact CrCLs; at equivalent angles of flexion, comparatively greater shear force affects the CrCLs in stifle joints with partial CrCL ruptures.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare biomechanical characteristics of vertebral segments after vertebral body plating or laminar stabilization following complete incision of the annulus fibrosus.

Sample—Vertebral segments from T13 through L3 obtained from 18 canine cadavers.

Procedures—A 4-point bending moment was applied in flexion and extension to the intact vertebral segments to determine a baseline range of motion (ROM) and neutral zone (NZ). Vertebral columns were then destabilized by creating a defect in the intervertebral disk via complete incision of the ventral aspect of the annulus fibrosus. The bending moment was applied again after stabilization was accomplished via vertebral body plating or with laminar stabilization (n = 9 vertebral segments/stabilization technique). The ROM and NZ were compared with their baseline values and among treatment groups. Finally, load-to-failure testing was performed in flexion.

Results—Mean relative ROM and NZ for segments treated with laminar stabilization were significantly lower than those for segments treated with vertebral plates.

Conclusions and Clinical Relevance—Analysis of in vitro results suggested that laminar stabilization of vertebral segments provided greater stiffness than did vertebral body plating.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine angles of insertion for laminar vertebral fixation of L1 and L2 by use of a locking plate in dogs and to confirm screw placement by use of computed tomography (CT).

Sample—Vertebral specimens harvested from 8 canine cadavers.

Procedures—The point of insertion and minimum and maximum insertion angles for laminar and facet screws for laminar vertebral stabilization were determined by use of CT. A precontoured locking plate was then placed by use of 1 locking screw in the lamina of each lumbar vertebra and 1 nonlocking screw in the facet joint. The position and angle of the screws were examined by use of CT, and penetration into the vertebral canal was recorded.

Results—Mean ± SD insertion angles for L1 and L2 were 18 ± 4° and 21 ± 5° toward the vertebral canal and 11 ± 4.4° and 10 ± 3° in a dorsal direction, respectively. Insertion angles for the facet joint were between 24 ± 4° ventrally and 12 ± 2° dorsally. Insertion of the screw did not penetrate the vertebral canal for 23 of 24 (96%) screws. For 23 of 24 inserted screws, the previously determined angle was maintained and purchase of bone and cortices was satisfactory.

Conclusions and Clinical Relevance—Placement of laminar and facet screws in canine vertebrae was possible and can be performed safely if angles of insertion determined pre-operatively via CT are maintained.

Full access
in American Journal of Veterinary Research