scholarly journals Biomechanical comparison of ex vivo lumbar vertebral fracture luxations stabilized with tension band or polymethylmethacrylate in cats

2020 ◽  
Vol 49 (8) ◽  
pp. 1517-1526
Author(s):  
Patricia Beer ◽  
Sebastian C. Knell ◽  
Antonio Pozzi ◽  
Brian H. Park
Author(s):  
Esa V. Eskelinen ◽  
Ari P. Suhonen ◽  
Juha V. Virolainen ◽  
William D. Liska

Abstract Objectives The purpose of this study was to compare the load at failure, stiffness and mode of failure between three types of tibial tuberosity transposition fixation techniques: (a) pin and figure-8 tension band wire (Pin-TBW), (b) locking plate with pin and a tension band wire (Plate-Pin-TBW) and (c) locking plate with a pin (Plate-Pin). Methods Six pairs of raccoon dog cadaveric tibiae were tested in Phase I Pin-TBW versus Plate-Pin-TBW and seven pairs in Phase II Plate-Pin-TBW versus Plate-Pin. One limb of each pair was randomly assigned to one of two groups for each phase. A tensile force was applied to the patellar ligament until construct failure. Results Pin-TBW (342N ± 54.7N) failed at a lower load than Plate-Pin-TBW (469N ± 77.3N), p = 0.00748, with all Pin-TBW failing by fracture and the majority of Plate-Pin-TBW failing by rupture of patellar ligament. Pin-TBW group Phase I, normalized with Plate-Pin-TBW Phase I, failed at a lower load than Plate-Pin group Phase II, normalized with Plate-Pin-TBW Phase II, p = 0.00467. There was no significant difference in mean load at failure, stiffness or mode at failure between the groups in the Phase II study. Clinical Significance Although ex vivo mechanical testing does not replicate the postoperative live dog or cat, these results demonstrate lower construct strength of the Pin-TBW construct compared with the Plate-Pin construct in the raccoon dog cadaver model.


2015 ◽  
Vol 9 (6) ◽  
pp. 361-369
Author(s):  
L.R. Mesquita ◽  
L.A.L. Muzzi ◽  
J.T. Lima ◽  
R.A.L. Muzzi ◽  
A.C.C. Lacreta Junior ◽  
...  

2014 ◽  
Vol 27 (04) ◽  
pp. 271-276 ◽  
Author(s):  
N. Bertollo ◽  
W. Walsh ◽  
K. Voss ◽  
M. Newman

SummaryObjectives: To evaluate the degree of lateralization achievable and strength of tibial tuberosity transposition and advancement (TTTA) relative to pin and tension band wiring (PTBW) for lateral tibial tuberosity transposition.Methods: Six pairs of cadaveric tibiae were used. Tibial tuberosity position was determined with computed tomography (CT); bones were then randomly assigned into TTTA and PTBW groups. The PTBW group had a tibial tuberosity osteotomy and fixation with pin and tension band wiring. The TTTA group had a tibial tuberosity advancement performed with lateralization of the tibial tuberosity by 50% of cage depth, using spacers on the cranial cage screw. Postoperative CT images showed lateralization and craniocaudal deviation. Single axial distractive loading was applied to the patella at 90° to the tibial plateau, and peak load, energy, and stiffness were calculated.Results: There were significant differences in lateralization (PTBW: 67.92 ± 5.1 %; TTTA: 88.51 ± 5.5 %) (p = 0.0173) and craniocaudal deviation (PTBW: –8.30 ± 1.4 %; TTTA: 6.83 ± 0.6) (p = 0.0001). There were no significant differences in peak load to failure (N) (PTBW: 1448 ± 121; TTTA: 1597 ± 43) (p = 0.4541), energy to failure (N/mm) (PTBW: 15013 ± 2719; TTTA: 17314 ± 887) (p = 0.646), or stiffness (N/mm)(PTBW: 102.8 ± 4.7; TTTA: 92.9 ± 4.8) (p = 0.2716).Clinical significance: The TTTA was more effective at lateralization of the tibial tuberosity, and of comparable strength to PTBW. Greater support of the osteotomized fragment with TTTA may resist cyclic loading, and requires evaluation.


2020 ◽  
Vol 48 ◽  
Author(s):  
Fernando Bezerra Da Silva Sobrinho ◽  
Ivan Felismino Charas Dos Santos ◽  
Claudia Valéria Seullner Brandão ◽  
Sheila Canevese Rahal ◽  
César Passareli Cândido Lobo ◽  
...  

Background: Acute spinal traumas can lead to irreversible damage associated with vascular and inflammatory changes in neural tissue. Since spine and spinal cord traumas have an unfavorable prognosis in small animals, and reports of the use of Steinmann pins and polymethylmethacrylate repair of lumbar vertebra fracture-luxation in puppies are rare in the literature, the present paper aimed to report the surgical treatment of transversal fracture through the body of the fourth lumbar vertebra, with dorsocranial displacement of the caudal fragment by using Steinmann pins and polymethylmethacrylate in a 7-month-old Labrador Retriever male dog.Case: A 7-month-old intact male Labrador Retriever dog, weighing 24.0 kg was attended at School Veterinary Hospital with a history of hit by car and paraplegia of the hind limbs. On neurological examination was observed no proprioception and no deep pain sensitivity on the both pelvic limbs. The lumbar spinal palpation showed intense pain, and the motor function and patellar reflexes were reduced. The values of haematological and biochemical analysis remained within the reference values for the species. Radiographs revealed a transversal fracture through the body of the fourth lumbar vertebra, with dorsocranial displacement of the caudal fragment, and was decided to perform a surgical treatment by open reduction and internal fixation of the fracture. The dog was positioned in ventral recumbency for surgery, and a dorsal midline incision was made from the second lumbar vertebra to the sixth lumbar vertebra. Two crossed 1.5 mm Kirschner wires were placed through the caudal articular facets of the fourth lumbar vertebra to provide initial stability. Two 2.0 mm Steinmann pins were placed at 60° angle of the bodies of the second and fifth lumbar vertebrae, and third and fourth lumbar vertebrae. This procedure was repeated on the other side of the vertebral bodies. Sixty grams of polymethylmethacrylate bone cement was applied and the fixation was checked for stability. Muscular, subcutaneous tissue and skin was closed routinely. The dog was paraplegic without any pain and used a wheelchair to assist in locomotion, although it still had urinary and faecal incontinence; no tail control; and the implants were not removed.Discussion: Lumbar vertebral injuries, as in the present case frequently, occur secondary to severe trauma (e.g. hit by car) and seem to have a characteristic fracture pattern. The patient became paraplegic due to spinal cord injury and failure of sensitivity and elimination of urine and feces which can be associated with progressive destruction of neuronal tissue due to secondary vascular and inflammatory events. The radiographic exam was used to confirm the spinal injury and determine whether by conservative or surgical treatment. The treatment choice is related to the number of fractured compartments, and the presence or not of compression. Fractures in two or more compartments are indicative of surgical treatment, similar as the present case. Use of Steinmann pins was to make a rigid fixing system compared with block plates used for the same function. Use of polymethylmethacrylate may also become a complication due to the infection, for this reason was prescribed an antibiotic for 15 days. This procedure proved to be effective since the dog showed no signs of infection. According to the characteristics of the present case report, the use of Steinmann pins and polymethylmethacrylate for repair of transversal fracture through the body of the fourth lumbar vertebra, with dorsocranial displacement of the caudal fragment provided an effective and practical means of stabilisation, promoting decompression, and thus, improving the patient's quality of life.


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