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.

Circumferential measurement of anulus deviation after laser nucleotomy.

Background And Objective: Former studies investigated only the intradiscal pressure after laser nucleotomy. As the outer anulus causes compression of neural structures, the present in vitro study was performed to investigate the circumferential pressure conditions of the outer posterolateral anulus following laser nucleotomy.

Study Design, Materials And Methods: Laser nucleotomy was performed using a Hol:YAG laser (14 Watt, total energy applied 10kJ).

Limb salvage in periacetabular sarcomas: review of 21 consecutive cases.

The oncologic and functional outcome was reviewed in 21 consecutive patients who underwent limb salvaging surgery for periacetabular sarcoma using a new surgical approach and different types of reconstruction between 1972 and 1990. Histologic diagnosis in 86% showed osteosarcomas, chondrosarcomas, and Ewing's tumors. Age ranged from 10.

Erb:YAG and Hol:YAG laser osteotomy: the effect of laser ablation on bone healing.

Sixty-nine male Sprague Dawley rats were divided into three groups of 23 animals each and osteotomies were performed in group 1 with a power saw, in group 2 with the Erb:Yag laser, and in group 3 with the Hol:YAG laser. Two animals of each group were sacrificed 1 week, 4, 8, and 12 weeks after operation for histologic investigation, and five animals of each group at 4, 8, and 12 weeks after osteotomy for torque testing. Anterior-posterior (AP) radiographs were taken at the same time points and investigated for callus formation and development of pseudoarthrosis.

[Cement-free Zweymüller hip system. Results of a 5-year follow-up study].

85 patients with 96 cementless pressfit hip implants were followed over a period of at least 5 years postoperatively. Average Harris score was 87.5 points.

Comparison of tuberculous and pyogenic spondylitis. An analysis of 122 cases.

One hundred twenty-two patients with tuberculous or pyogenic spondylitis were investigated retrospectively. Patient histories, laboratory tests, and radiographic findings were compared statistically between the two groups. Significant differences were calculated for the interval between onset of symptoms and diagnosis, erythrocyte sedimentation rate, mean vertebral loss at discharge, and sclerosis of the vertebral bodies involved.

Ablation of polymethylmethacrylate by Ho:YAG, Nd:YAG, and Erb:YAG lasers.

Ho:YAG, Nd:YAG, and Erb:YAG laser ablation of Polymethylmethacrylate (PMMA) was investigated under in vitro and simulated clinical conditions. Ablation rates were measured for all lasers and after ablation, macroscopic and microscopic appearance of the ablation site was investigated. The mean ablation rates of the Erb:YAG, Ho:YAG, and Nd:YAG laser increased from 8 microns per pulse at 100 mJ to 44 microns per pulse at 300 mJ from 100 microns per pulse at 200 mJ to 222 microns per pulse at 800 mJ and from 28 microns per pulse at 100 mJ to 189 microns per pulse at 800 mJ, respectively.

Midterm experience with the cementless Zweymueller system. Results of a minimum five-year follow-up study.

Eighty-five patients with 96 cementless press-fit hip implants were followed over a period of at least 5 years postoperatively. The average Harris score was 87.5 points.

[Sonographic structural analysis of the Achilles tendon and biomechanical implications].

Ruptures of the Achilles tendon mainly occur on the ground of predisposing destruction of tendon structure. The aim of this retrospective US study was to evaluate the location and extent of tendon abnormalities. 62 patients (49 male, 13 female; 19 to 57 years, mean 38) with achillodynia of short duration and/or clinically suspected tendon abnormalities were evaluated sonographically.

Erb:YAG and Hol:YAG laser ablation of meniscus and intervertebral discs.

Erb:YAG and Hol:YAG laser ablation rates of fibrocartilage and nucleus pulposus were measured in vitro simulating clinical conditions. After ablation macroscopic and microscopic appearance of the ablation site was investigated. Hol:YAG and Erb:YAG laser mean ablation rates increased almost linearly with rising energies, showing higher total ablation rates for the Hol:YAG laser due to its higher achievable energy density.

Chiari pelvic osteotomy for osteoarthritis secondary to hip dysplasia. Indications and long-term results.

Of 142 Chiari pelvic osteotomies for osteoarthritis in dysplastic hips, most performed by Chiari himself, we were able to review 82 and obtain information about 18 by questionnaire. All patients were over 30 years of age at operation; follow-up averaged 15.5 years.

Fluorescence guided excimer laser ablation of intervertebral discs in vitro.

Laser induced fluorescence of intervertebral discs was investigated in this study for the first time in order to develop a fluorescence guided percutaneous excimer laser discectomy. For this purpose 35 human cadaveric intervetebral discs from level L1 to L5 were irradiated with a 308 nm XeCl excimer laser with a 60 nsec pulse width at 10, 20 and 30 mj/mm2. Laser light was transmitted over a 1000 microns core optical fiber.

[Clinical and radiologic comparison of "idiopathic" and "neurogenic" pes cavus].

41 patients with 66 cavus feet were reviewed clinically and radiologically according to the parameters of Dennemann at an average age of 41.3 years. The etiology was a so-called "idiopathic pes cavus" in 51 per cent of the cases, in the others, a neurological basic disease (15 per cent condition after poliomyelitis, 3 per cent meningocele, 6 per cent Friedreich's ataxia, 10.