Less invasive lumbopelvic stabilization of posterior pelvic ring instability: technique and preliminary results

Lumbopelvic distraction stabilization with (triangular osteosynthesis) or without additional iliosacral screw allows anatomic reduction of the posterior pelvic ring after severely displaced sacral fractures, correction or resection osteotomies of malunions, respectively, septic sacroiliitis and permits early weight bearing. However, this technique is complicated by wound necrosis or infection in up to 20% to 30%. We describe our experience with a less invasive technique.

Model Predictive Control for Vehicle Stabilization at the Limits of Handling

Recent developments in vehicle steering systems offer new opportunities to measure the steering torque and reliably estimate the vehicle sideslip and the tire-road friction coefficient. This paper presents an approach to vehicle stabilization that leverages these estimates to define state boundaries that exclude unstable vehicle dynamics and utilizes a model predictive envelope controller to bound the vehicle motion within this stable region of the state space. This approach provides a large operating region accessible by the driver and smooth interventions at the stability boundaries. Experimental results obtained with a steer-by-wire vehicle and a proof of envelope invariance demonstrate the efficacy of the envelope controller in controlling the vehicle at the limits of handling.

Stabilization of Juxta-Physeal Distal Tibial and Fibular Fractures in a Juvenile Tiger Using a Hybrid Circular-Linear External Fixator

OBJECTIVE: To report stabilization of closed, comminuted distal metaphyseal transverse fractures of the left tibia and fibula in a tiger using a hybrid circular-linear external skeletal fixator. STUDY DESIGN: Clinical report. ANIMAL: Juvenile tiger (15 months, 90 kg). METHODS: From imaging studies, the tiger had comminuted distal metaphyseal transverse fractures of the left tibia and fibula, with mild caudolateral displacement and moderate compression. Multiple fissures extended from the fractures through the distal metaphyses, extending toward, but not involving the distal tibial and fibular physes. A hybrid circular-linear external skeletal fixator was applied by closed reduction, to stabilize the fractures. RESULTS: The fractures healed and the fixator was removed 5 weeks after stabilization. Limb length and alignment were similar to the normal contralateral limb at hospital discharge, 8 weeks after surgery. Two weeks later, the tiger had fractures of the right tibia and fibula and was euthanatized. Necropsy confirmed pathologic fractures ascribed to copper deficiency. CONCLUSION: Closed application of the hybrid construct provided sufficient stability to allow this 90 kg tiger's juxta-articular fractures to heal with minimal complications and without disrupting growth from the adjacent physes.

Use of a 1.5 mm butterfly locking plate for stabilization of atlantoaxial pathology in three toy breed dogs

The objective of this study was to describe the use of a titanium 1.5 mm locking plate in the stabilization of atlantoaxial pathology in three toy breed dogs. Two dogs with atlantoaxial subluxation and another dog with an axial fracture, confirmed by diagnostic imaging, were stabilized via a ventral approach with a 1.5 mm titanium 5-hole locking butterfly-plate. Surgical reduction and stabilization were assessed by computed tomography and radiography after surgery. Follow-up evaluation for resolution of neurological signs and possible complications was performed in all three dogs. For long-term assessment, a telephone follow-up was performed. A considerable improvement of neurological signs occurred within two to four weeks after surgery. An excellent clinical outcome was identified in all three patients. Adequate stabilization and resolution of neurological signs in all three dogs was achieved. The stabilization of atlantoaxial surgical conditions in toy breeds with the 1.5 mm titanium 5-hole butterfly locking plate appears to be an effective means of surgical treatment.