Mobility-Maintaining Facet Arthroplasty of the Lumbar Spine With the Second-Generation TOPS System: A Case Series.

Background: Lumbar spinal stenosis results from spinal canal narrowing and can lead to pain and dysfunction. Until recently, surgical treatment for lumbar spinal stenosis requiring an extensive decompression, with or without spondylolisthesis, had to balance pain relief with the long-term risks of spinal instability after decompression and adjacent segment disease (ASD) after spinal fusion. Spinal motion-preserving devices aim to reduce the incidence of ASD after posterolateral fusion and consequent need for revision surgery.

Self-induced acoustic transparency in semiconductor quantum films.

We develop a quantum theory of the nonlinear interaction between intense surface acoustic waves and electrons in a quantum well in the regime of moving quantum wires and dots. In the quantum nonlinear regime, the sound attenuation exhibits quantum oscillations and dramatically decreases with increasing quantization. In the case of dynamically created electron dots formed by two acoustic waves, the waves can propagate without any dissipation in the limit of high sound intensity and, hence, the electron quantum film acts as an acoustically quasitransparent material.

Comparative study of surface displacement in discs following chemonucleolysis and lasernucleotomy.

Background And Objective: Dynamic changes of the dorsolateral protrusion site have been postulated to play an important role in the therapeutic effect of lasernucleotomy and chemonucleolysis. Basic biomechanical effects of the anulus after lasernucleotomy and chemonucleolysis are investigated.

Study Design/materials And Methods: This study evaluates the in vitro bulging of lumbar discs comparing lasernucleotomy and chemonucleolysis.

[Position of the patella after knee endoprosthesis. A by radiology and computerized tomography controlled study].

The position of the Patellaimplant of 35 total knee arthroplasties (PCA) in regard to the other components, to patellar ligament and to correction of axis was analysed. The position of the patella was investigated with an average follow up of 38 months both radiologically and by computed tomography. A lateralisation of 4 mm on average and a lateral tilting of 4 degrees on average were found.

Bone-ligament transfer of coracoacromial ligament for acromioclavicular dislocation. A new fixation method used in 6 cases.

We treated 6 grade III acromioclavicular injuries with a new fixation method using a bone-ligament transfer of the coracoacromial ligament into a clavicular tunnel. After an average of 16 months, function and cosmesis were excellent in all patients.