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This series includes 59 consecutive patients, 51 of whom had a minimum follow up of 2 years. The diagnosis was mechanical instability in 39, deformity in 11, and infection or tumor in 9 patients. The overall clinical results of the total group were good or fair in 88% of the patients. Pseudarthrosis occurred twice. We had on postoperative infection, one persistent and two reversible neurological complications. We found 13 broken screws and one rod breakage which had no clinical relevance. None of these asymptomatic complications required revision. The internal fixator has a great potential of correction in scoliotic and kyphotic deformities of the spine. It has not been shown to have the same potential in spondylolisthesis. A combined anterior and posterior stabilisation is needed in severe spondylolisthesis. We have found the internal fixator to provide satisfactory stability to allow fusion and good clinical results with a low rate of relevant complications.

There have been no previous reports of a spinal subdural haematoma occurring as a complication of spinal surgery. We highlight the pitfalls in the diagnosis and management of a subacute subdural haematoma resulting from a dural tear which occurred as a surgical complication of microdiscectomy.

Laser spectroscopy measurements have been carried out on very neutron-deficient isotopes of Au, Pt and Ir, produced as daughter elements from a Hg ISOLDE beam. For these transitional region nuclides, the hyperfine structure (HFS) and isotope shift (IS) were measured by Resonance Ionization Spectroscopy (RIS). Magnetic moments μ, spectroscopic quadrupole moments Qs and changes of the nuclear mean square charge radius δ〈rc 2〉along isotopic series have been extracted. For some results, a detailed comparison with theoretical predictions is presented.

Three cases of spondylodiscitis caused by viridans streptococci were observed within the course of 1 month. Although streptococci have been reported as the third most frequent cause of spondylodiscitis after staphylococci and gram-negative bacteria, alpha-haemolytic streptococci are rarely seen. The three patients presented with symptoms of low back pain; they felt well and did not have a fever or chills. Laboratory examinations revealed inflammation. Further examinations such as scintigraphy, computed tomography or magnetic resonance imaging were done. Bacteriological diagnosis was established by blood cultures in two cases and by needle biopsy of the disco-vertebral space in one. In one patient endocarditis was also documented. Because the prevalence of endocarditis was found to be higher in our cases of spondylodiscitis due to Streptococcus viridans than for other bacteria, the exclusion of this diagnosis must be pursued aggressively. These observations lead us to question if the spectrum of bacteria causing spondylodiscitis is undergoing a change. an aetiological agent could be isolated in 1168 patients (85.4%): in 48% a staphylococcus, in 28% a gram-negative bacterium and in only 10% a streptococcus. There were two cases of viridans streptococci (0.2%). These two cases together with other single case reports [14-22] account for 15 cases of spondylodiscitis due to alpha-haemolytic streptococci. Differentiation of the organisms to the species level was accomplished in six cases: S. mitis (3), S. sanguis (2) and S. anginosus (1). Although a multitude of organisms, bacterial as well as fungal, causing spondylodiscitis has been reported in recent years, almost all were single cases [23-42]. The unusual observation of three cases of spondylodiscitis due to alpha-haemolytic streptococci within 1 month prompted us to review the clinical and laboratory findings and to compare these cases with those caused by Staphylococcus aureus.

Type X collagen has so far not been reported to occur in human intervertebral discs. The objective of this study was therefore to investigate the occurrence of type X collagen in human lumbar intervertebral discs during ageing and degeneration. Ninety intervertebral discs with adjacent endplates were excised in toto from individuals (0-86 years) without known spinal disease and were processed for routine decalcified histology. Appropriate slices of each disc were processed for immunohistochemistry using a type-specific, monoclonal antibody raised against human type X collagen. Each intervertebral disc was examined for macroscopic and histomorphological features of disc degeneration. Immunohistochemically, a positive specific type X staining was observed in the hypertrophic zone of the growth plate and only in the interstitial matrix of juvenile (2 years) nucleus pulposus. In adult discs, type X collagen could be localized in conjunction with advanced disc degeneration and first occurred in the disc matrix (i.e., pericellular region) of a 47-year-old specimen. Positive type X staining of the disc matrix was more frequently found in senile (70 years) discs with end stages of disc degeneration. This study provides the first evidence for the occurrence of type X collagen in human lumbar intervertebral discs and it appears that type X collagen is re-expressed in late stages of disc degeneration.

A 40-band integrated static gain-flattening filter (GFF) is presented. The design of the filter was optimized using a newly developed analytical model, which shows a good agreement with the experimental results. The filter has a low insertion loss of 4.1 dB, an attenuation range that exceeds 20 dB, and is able to generate slopes above 20 dB/nm. It is a first step toward an integrated high-resolution dynamic GFF.

The first successful laser cooling of ions at relativistic energies was observed at the Heidelberg TSR storage ring. A $^{7}\mathrm{Li}^{+}$-ion beam of 13.3 MeV was oberlapped with resonant copropagating and counterpropagating laser beams. The metastable ions were cooled from 260 K to a longitudinal temperature of below 3 K and decelerated by several keV. The longitudinal velocity distribution was determined by a fluorescence method. After laser cooling a strongly enhanced narrow peak appeared in the Schottky noise spectrum in addition to the uncooled ion distribution.

Experimental results of an 8 tap dynamic gain flattening filter (DGFF) are presented. This device consists in a planar silica on silicon lightwave optical circuit including tunable couplers and delay lines. In this paper we will discuss both optical performances and the control scheme.

Long-haul transmission across six 640/spl times/640 (320 working+320 protection) wavelength-selective cross-connects, interconnected by six 125 km spans of Raman-amplified NZ-DSF fiber using 32 wavelengths at 10 Gb/s, is reported. System configuration, and optical signal to noise ratio (OSNR) and Q performances are presented.

Osteoporosis plays an increasing medical, social, and economic role in our society. Vertebral body fractures are the most common fractures, along with fractures around the hip joint, and fractures of the distal radius due to osteoporosis. An osteoporotic vertebral compression fracture can lead to incapacitating back pain and immobility and often requires in-hospital treatment. Vertebroplasty is an effective procedure consisting of the percutaneous injection of polymethylmethacrylate (PMMA) cement into vertebral bodies. Preliminary studies showed promising clinical results with this new technique. As there is a high incidence of cement leakage during the injection of the cement, we prefer to perform the procedure under computed tomography control with a fluoro-CT-option. Furthermore, we recommend that the procedure is only done in collaboration with a spine surgeon. In case of a neurological complication, immediate decompression of the spinal canal is mandatory. Vertebroplasty is a very promising, effective and safe method for the treatment for osteoporotic vertebral compression fractures. Based on our preliminary results, this method can be recommended for a more widespread clinical use.

Low-back pain is a very common but benign and in general self-limiting disease indicating that only a small proportion of the patients will require sophisticated imaging studies. Recent studies have highlighted that a simple relation of structural abnormalities to low-back pain is impossible because similar alterations can be found in symptomatic as well as in asymptomatic individuals. These findings question our current criteria for the diagnosis of low-back pain disorders with regard to their discriminative power in differentiating diseased and non-diseased individuals. Structural abnormalities demonstrated by imaging studies should therefore only be interpreted in the light of the clinical findings. This review has shown that only a few studies contribute to our understanding of the clinical efficacy of imaging studies in the evaluation of low-back pain disorders. There is an absolute need for comprehensive well conducted studies on the impact of specific image modalities on diagnosis and treatment of lumbar spinal disease.

The high incidence of non-specific, benign back trouble often delays the diagnosis of specific causes of back pain and thus result in neurological deficits. Degenerative abnormalities in the cervical spine may narrow the spinal canal and result in acute myelopathy subsequent to minor injuries. Large cervical or lumbar disc herniations causing myelon, conus or cauda equina compression are rare but must not be overlooked. Spinal metastases may remain unrecognised for a long period and lead to the correct diagnosis only after presentation with neurological deficits. Acute myelopathy or cauda equina syndrome are indications for immediate diagnostic assessment and treatment in a spine centre.

We report on a case of chondromyxoid fibroma involving two adjacent thoracic vertebrae with features of aggressive behaviour on radiographs, CT and MRI. Histology revealed typical chondromyxoid fibroma with unusually coarse calcifications. Chondromyxoid fibroma of the spine is rare, and only 30 of these tumours have been reported so far. Involvement of two contiguous vertebral bodies by chondromyxoid fibroma, as reported here, appears exceptional.

The diagnostic assessment of the low back pain patient is often unsatisfactory because a clear morphological alteration explaining the patient's symptoms can only be found in 10-20% of the cases. The majority of the patients is suffering from non-specific low back pain. However, the high incidence of benign, self-limiting low back pain leads to the risk of overlooking specific causes such as tumor or infection. Similarly, relevant paresis and bladder and bowel dysfunction must be diagnosed in time. Furthermore, the aim of the diagnostic work-up is to diagnose and treat specific causes of back and leg pain (e.g. disc herniation and spinal stenosis) to avoid chronicity. In the majority of the cases, history and clinical examination alone allow to differentiate between specific and non-specific low back pain and may lead to a further diagnostic work-up by imaging studies.

The rapid growth in demand for bandwidth in telecommunication links created by the increase in Internet and high-speed data traffic and the speed limitation of single wavelength links has resulted in an increase in the deployment of wavelength division multiplexing (WDM) techniques in advanced lightwave systems. In WDM, the fiber bandwidth is easily accessed in the wavelength domain and it is possible to perform functions such as switching and routing. WDM can employ existing intensity modulation-direct detection systems and offers the advantage of being protocol and bit-rate independent. A typical WDM link is shown. Various techniques (fiber based gratings, bulk gratings, thin film, arrayed waveguide gratings) exist to fabricate the wavelength multiplexers and demultiplexers which are needed to combine the signals at the transmitter side and separate the distinct signals at the terminal end. Arrayed waveguide gratings (PHASARs) made by planar fabrication techniques are a particularly attractive approach to devices with high port counts, narrow channel spacing and low cost; moreover they are highly versatile components which can be integrated into wavelength selective switches such as add/drop multiplexers (ADM) and optical crossconnects (OXC).

We report a case of progressive thrombotic occlusion of the left common iliac artery in a 41-year-old woman after anterior interbody fusion, which initially presented only as a sensation of numbness. Diagnosis was delayed until complete arterial occlusion occurred 36 h after surgery. A sensory deficit may be the only early sign of a progressive thrombotic arterial occlusion. In anterior spinal surgery, routine postoperative vascular monitoring of the lower extremities is recommended and mandatory for early diagnosis and treatment of this rare complication.

Deformation changes δβ have been found out between isomeric and ground states of the 183Pt and 184Au isotones. Atomic spectroscopy measurements by laser were carried out using the COMPLIS setup. Hyperfine structure (HFS) spectra and isotope shift (IS) were obtained for the 5d96s 3D3→5d96p 3P2 and 5d106s 2S1/2→5d106p 2P3/2 optical transitions in Pt and Au atoms respectively, providing deformation parameters β and nuclear moments μ and Qs. The influence of the proton-neutron coupling on the δβ value in 184Au relatively to its isotone 183Pt has been determined. Besides, the h9/2 proton state that is decoupled from the core in 183,185Au, becomes the 3/2[532] state (h9/2 parentage) strongly coupled in the doubly-odd 184Au nucleus.

We compared 74 total hip arthroplasties (THAs) carried out after previous proximal femoral osteotomy with a diagnosis-matched control group of 74 primary procedures performed during the same period. We report the perioperative results and the clinical and radiological outcome at five to ten years. We anticipated a higher rate of complications in the group with previous osteotomy, but found no significant difference in the rate of perioperative complications (11% each) or in the septic (8% v 3%) and aseptic (4% each) revision rates. There was a trend towards improved survival in the group without previous osteotomy (90% v 82%), but this difference was not statistically significant. The only significant differences were a higher rate of trochanteric osteotomy (88% v 14%) and a longer operating time in the osteotomy group. Our study indicates that THA after previous osteotomy is technically more demanding but not necessarily associated with a higher rate of complications. Furthermore, proximal femoral osteotomy does not jeopardize the clinical and radiological outcome of future THA enough to exclude the use of osteotomy as a therapeutic alternative in younger patients.

This review provides methodological background and some guidelines for the evaluation of imaging modalities for the lumbar spine and reviews the current literature on the basis of different levels of efficacy which consider standards beyond technical quality or diagnostic accuracy. From a MEDLINE search, 672 articles (1985-1995) were retrieved which focused on the development or application of imaging modalities for lumbar spinal disorders. The papers were categorized according to different efficacy levels at which the imaging modalities were assessed. This review has demonstrated that the vast majority of reports evaluate imaging studies for the lumbar spine only at the technical efficacy level. A minor proportion of the articles focus on the evaluation at the level of diagnostic accuracy. Articles which assess imaging studies on a higher level of efficacy (e.g., diagnostic and therapeutic impact, patient outcome and cost-benefit analysis) are sparse. This review has outlined frequent methodological flaws in patient selection and design of imaging studies for the lumbar spine. The spine specialist should therefore become very critical in the interpretation of those studies and pay attention to patient selection and spectrum, choice of the reference standard, sample size, various forms of biases, and the reasoning behind clinical recommendations in order to improve his patient care.

This was a prospective study of patients (study group) with symptomatic disc herniations and asymptomatic volunteers (control group) matched for age, sex, and work-related risk factors.To determine the prevalence of disc herniation in a matched group of asymptomatic volunteers and to access the diagnostic accuracy of magnetic resonance imaging, work perception, and psychosocial factors in identifying symptomatic disc herniations.Disc herniations have been reported to occur in 20-36% of asymptomatic volunteers. A valid comparison of asymptomatic individuals and patients with disc herniations has not been performed.Forty-six patients with low back pain and sciatica severe enough to require a discectomy were compared with 46 age-, sex-, and risk factor-matched (heavy lifting, twisting and bending, vibration, and sedentary activity) asymptomatic volunteers. Both groups had a complete clinical and magnetic resonance imaging examination and completed a questionnaire to assess differences in the psychosocial and work perception profiles. The prevalence and the severity of morphologic alterations (disc herniation, disc degeneration, and neural compromise) was analyzed by tow independent radiologists in a blinded fashion. Differences between both groups regarding MRI findings, work perception (occupational mental stress, intensity of concentration, job satisfaction, and job-related resignation) and psychosocial factors (anxiety, depression, self-control, social support, and marital status) were compared using multivariate techniques. Stepwise discriminating analysis was used to identify the best discriminating variables within the magnetic resonance image, work perception, and psychosocial categories in terms of the diagnostic accuracy to predict group membership (study [pain] or control [no pain] group).Matched controls had significantly more risk factors than a group of normal individuals. The present study has presented evidence that an age-, gender-, and occupational risk factors-matched group of asymptomatic patients shows a high incidence rate of disc herniations (76%). Although significantly less than the symptomatic group incidence of 96%, this represents a much higher prevalence rate than generally expected and reported in other studies of unmatched asymptomatic volunteers. Patients had more severe disc herniations (disc extrusions) than asymptomatic volunteers (35% vs. 13%). There was no significant differences regarding disc degeneration between both groups (96% vs. 85%). The only substantial morphologic difference between both groups was the presence of a neural compromise (83% vs. 22%), which was highly significant (P0.0001). There were significant differences between both groups regarding work perception (occupational mental stress, intensity of concentration, job satisfaction, and resignation; P0.027) and psychosocial factors (anxiety, depression, self-control, marital status; P0.0001). The best single predictor of a group membership was the extent of neural compromise. A combination of this factor with occupational mental stress, depression, and marital status was the best predictive model. With this model, the false-negative rate (potential overtreatment of disc morphology) was reduced by more than half compared with morphologic factors (nerve root compression) alone (22% vs. 11%).In an age-, sex-, and risk factor-matched group of asymptomatic individuals, disc herniation had a substantially higher prevalence (76%) than previously reported in an unmatched group. Individuals with minor disc herniations (i.e., protrusion, contained discs) are at a very high risk that their magnetic resonance images are not a causal explanation of pain because a high rate of asymptomatic subjects (63%) had comparable morphologic findings. The only highly significant difference between the study group and control group regarding morphologic fi

The complete hyperfine spectrum in the optical transition 5d26s2 3P2→5d6s26p 1P1 of 178m2Hf was recorded by collinear laser spectrocopy using nanogram amounts of samples [1]. The quadrupole moment and isomer shift were determined for the first time as well as a precise value and the sign of the magnetic dipole moment. The change in nuclear mean‐square charge radius between the isomeric state 178m2Hf and the ground state 178gHf was evaluated as δ〈r2〉178,178m2=−0.059(9) fm2. From the hyperfine A‐ and B‐factors the magnetic moment γI178m2=+8.16(4)μN and the spectroscopic quadrupole moment Q178m2s=6.00(7) b were extracted. In an additional experiment using a RIS scheme we recorded the A‐ and B‐factors and the isotope shift of the 5d26s23 F3→5d26s6p 3G4 and the 5dd6s2 3P0→5d26s6p 3D1 transition.

The correction of posttraumatic kyphosis in the thoracolumbar region almost always requires a combined anterior and posterior approach because of the particular anatomic situation and the pathomorphologic changes. We suggest that the patient be placed in a right lateral decubitus position. This allows dual access to the spine by a posterior midline approach and a retroperitoneal thoracolumbar approach, so that simultaneous anterior and posterior manipulation, correction and stabilization of the spine are possible with no need to turn the patient intraoperatively. Thus, compared with two-or three-stage procedures, the duration of the operation and of stay in hospital can be reduced. This is a retrospective review of the first six patients (average age: 35 years) treated with this approach between 1987 and 1990. All patients suffered from incapacitating back pain that was unresponsive to nonoperative treatment. The surgical procedure was performed at an average of 29 months (range, 5 months to 7 years) after fracture. The average postoperative correction of kyphosis (18 degrees to 45 degrees) was 75%. In addition, two patients had posttraumatic scoliosis (10 degrees and 12 degrees), which was completely corrected. The only complication was partial fracture of a vertebral body in one case, which occurred during the reduction manoeuvre but had no consequences. Three of the patients had complete relief of pain. The remaining three reported persistent pain, although they had good objective clinical and radiological results. The failure to eliminate pain in these patients is thought to be a result of their long-standing (2-7 years) symptomatic posttraumatic deformities. Therefore, we feel that early correction of symptomatic kyphosis is mandatory.

Laser cooling of ions at relativistic energies was first observed at the TSR storage ring in Heidelberg. A 7Li+ ion beam moving at 6.4% the speed of light was overlapped with resonant co‐ and counter‐propagating laser beams. The longitudinal temperatures were found to pass below 190 mK. Limits and applications of laser cooled relativistic ion beams are discussed. Laser cooling and electron cooling of the ion beam were combined.

This series includes 59 consecutive patients, 51 of whom had a minimum follow up of 2 years. The diagnosis was mechanical instability in 39, deformity in 11, and infection or tumor in 9 patients. The overall clinical results of the total group were good or fair in 88% of the patients. Pseudarthrosis occurred twice. We had on postoperative infection, one persistent and two reversible neurological complications. We found 13 broken screws and one rod breakage which had no clinical relevance. None of these asymptomatic complications required revision. The internal fixator has a great potential of correction in scoliotic and kyphotic deformities of the spine. It has not been shown to have the same potential in spondylolisthesis. A combined anterior and posterior stabilisation is needed in severe spondylolisthesis. We have found the internal fixator to provide satisfactory stability to allow fusion and good clinical results with a low rate of relevant complications.

The vertebral column is a common site of metastatic disease to the bone. The incidence is very high and varies with tumor type. Radiation therapy is effective in the treatment of most cases of spinal metastases. Pathologic fractures of the vertebral body occur in 30-50% of the patients affected, indicating an operative intervention. The ultimate aim of the operation is to increase the patients' quality of life. The tumor mass is normally located in the vertebral body. Therefore, only with an anterior approach can excellent decompression of the spinal cord and reduction of the tumorous tissue be achieved. In patients with advanced metastatic disease, however, in whom an anterior approach is not practicable, tumor decompression may be accomplished through a costotransversectomy combined with posterior stabilization of the spine. Laminectomy is rarely indicated, and then for posteriorly located tumor tissue, and should be combined with dorsal stabilization of the spine. With reference to a few actual cases, we present the approaches and stabilization methods currently in use at our clinic.

The position of 119 pedicle screws was assessed on plain antero-posterior and lateral radiographs taken immediately post-operatively and at 3 months' follow-up. The readings of five independent observers were compared with the “gold standard” of CT reconstructions. The position of only 41 % of implants (range 14%–56%) was assessed correctly on the plain radiographs (47% on follow-up films). Two-thirds of CT-detectable perforations were missed. As shown with perforations of the anterior cortex, delectability increased significantly with magnitude of perforation. No specifically difficult anatomic level or direction of malplacement could be identified. Interobserver variation was considerable. Plain radiographs were shown to be of limited use in assessing the position of pedicle screws.

This report deals with 51 acute tibial fractures treated between 1981 and 1987 with a interlocking intramedullary nail. All fractures were extraarticular and located in the distal third. Fourty-four patients were followed up for an average of 32 months. The reduction was anatomic in 84%, with the remaining patients having angulation (valgus/antecurvation) of less than 5 degrees and shortening by less than 1 cm. The rate of local complications was 18%, and a secondary operation was required in 12%. There were no cases of deep infection. Bony union was achieved in every case. Overall, the results were judged to be excellent or good in 96% of the tibias. In this series we saw no poor results.

In each of 73 patients with acute knee injuries, both menisci were examined by means of 7.5-MHz sector-scan sonography before arthroscopy was performed. In 87% of the cases the sonographic and arthroscopic diagnoses were identical. The results were better for the lateral meniscus. Overall, the sensitivity was 80% and the specificity, 90%. False-positive and false-negative results each accounted for 6%. In this series there was no correlation between the accuracy of the sonographic diagnosis and the type of meniscal lesion or its location within the meniscus.

Three special cases of tabic arthropathy are reported. The disease is displayed in detail. One case showed an aneurysma of the arteria ulnaris. After resection of the aneurysma conservative treatment was performed. In a second case with active not yet diagnosed tabic hip a cemented total hip was implanted, which failed only 9 weeks later. The third case was an inactive tabic hip joint. The implantation of a cementless Autophor hip proved well. Total joint replacement has not to be performed in an active state of the disease, but can be done after consolidation. The significance of the VDRL-test for justing the activity of the disease is displayed.