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N Boos

Publications and source records attributed to N Boos.

54 records · Page 3Linked to original sources
PubMed1996

Clinical efficacy of imaging modalities in the diagnosis of low-back pain disorders.

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.

Bias↗
PubMed1995

1995 Volvo Award in clinical sciences. The diagnostic accuracy of magnetic resonance imaging, work perception, and psychosocial factors in identifying symptomatic disc herniations.

STUDY DESIGN: 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. OBJECTIVE: 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. SUMMARY OF BACKGROUND DATA: 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. METHODS: 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). RESULTS: 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 (P < 0.0001). There were significant differences between both groups regarding work perception (occupational mental stress, intensity of concentration, job satisfaction, and resignation; P < 0.027) and psychosocial factors (anxiety, depression, self-control, marital status; P < 0.0001). 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%). CONCLUSIONS: 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

Adult↗
PubMed1995

Quantitative magnetic resonance imaging of the lumbar spine. Potential for investigations of water content and biochemical composition.

Quantitative magnetic resonance imaging (relaxation time and proton density measurements) has gained increasing interest as a noninvasive way to study changes in water content and biochemical composition of lumbar intervertebral discs and vertebral bodies. This article reviews the current methodological problems and the feasibility of quantitative magnetic resonance imaging in the lumbar spine for investigations on water content and biological composition. This technique does not allow direct quantification of water content. Although biochemical variations may sensitively influence relaxation times and proton density under in vitro conditions, it is not feasible to obtain sufficiently reliable and specific information to monitor biochemical alterations associated with lumbar disc pathology in vivo.

Body Water↗
PubMed1994

Quantitative MR imaging of lumbar intervertebral disc and vertebral bodies: methodology, reproducibility, and preliminary results.

Since relaxation times are influenced by the hydration of the tissue and the chemical environment of the water molecules, T1 and T2 measurements (quantitative MRI) could be used as an indicator for the water content and the biochemical composition of lumbar intervertebral discs. The discriminating power of quantitative MRI for tissue characterization in individuals (for clinical diagnosis) and in cohorts (e.g. for investigations on disc physiology or composition) relies on the reproducibility in relation to the expected tissue differences. We therefore investigated the reproducibility in vitro (lumbar spine phantom) and in vivo (10 volunteers). To estimate the differences between normal and pathologic tissues in vivo, 100 normal and 20 herniated intervertebral discs were examined by quantitative MRI in a first application of our method. The relaxation times were calculated from a set of 20 images obtained with five single-slice/multi-echo sequences at different TR values on a commercial whole-body system (1.5 T). We have found a satisfactory reproducibility in vitro (T1: 1.9%; T2: 6.2%), while the reproducibility was less satisfactory in vivo (T1: 16.4%; T2: 13.4%). Calculated from theses values, differences in relaxation times of various tissues must exceed 486 ms for T1 and 24 ms for T2 (tolerance limits) to allow discrimination with a 95% confidence in individuals. We observed statistically significant (p = 0.001) mean differences between normal (n = 100) and herniated (n = 20) intervertebral discs (delta T1: 196 ms; delta T2: 15 ms). Although statistical significant in cohorts, a discrimination of normal and herniated intervertebral discs is limited by quantitative MRI in individuals, since the differences are smaller than the tolerance limits necessary for a reliable clinical diagnosis. However, our results indicate that variations in the disc hydration and/or composition can be noninvasively detected by quantitative MRI in studies of cohorts with sufficient accuracy.

Adolescent↗
PubMed1993

Treatment of severe spondylolisthesis by reduction and pedicular fixation. A 4-6-year follow-up study.

Ten consecutive patients with severe spondylolisthesis were treated with reduction and pedicular fixation (four Internal Fixator instrumentations, six Cotrel-Dubousset instrumentations). There were six Grade III spondylolisthesis and four spondyloptoses at the L5/S1 level. All patients had complete clinical and radiographic evaluation with an average follow-up of 56 months (range, 43-75 months). The percentage of slippage averaged 78.5% preoperatively and 39.6% postoperatively. The slip angle averaged 43 degrees preoperatively and 17 degrees postoperatively. Four patients with spondyloptosis were treated with combined posterolateral and interbody fusion and had solid fusion without loss of reduction. Five of six patients in whom reduction and stabilization was performed by a single posterolateral fusion demonstrated loss of reduction, nonunion, and implant failure. Four of these patients were reoperated. Ultimately all patients had resolution of pain, solid fusion, and no further slip progression. Reduction, pedicular fixation, and combined posterolateral and interbody fusion is a technically demanding procedure, which should be reserved for selected patients. Pedicular fixation systems may only allow permanent reduction and stabilization of high-grade spondylolisthesis in conjunction with a combined interbody and posterolateral fusion.

Adolescent↗
PubMed1993

Surgical treatment of tumors of the cervical spine and first two thoracic vertebrae.

From 1985 through 1990, 19 patients with tumorous conditions of the cervical spine and the first two thoracic vertebrae were treated with anterior, posterior, or combined anterior/posterior surgical techniques. Breast metastases were by far the most common condition (42%). Patients usually experienced severe pain, which resisted conservative treatment, sometimes associated with radiculopathies (42%) or neurological deficits (31%). To date, the treatment of spinal tumors is only palliative, and surgery must be considered for cases with unremitting neck pain, major vertebral destruction with loss, or impending loss of cervical spine stability and neurological deficits due to local tumor compression. Contrary to the commonly used posterior wiring stabilizations, we preferred stabilization techniques more closed to those used in traumatology. Our findings suggest anterior surgery alone with vertebrectomy and stabilization with plate and bone cement for tumors involving only one vertebra and localized between C3 and T1. Posterior approach and stabilization is advocated for atlantoaxial lesions. A combined anterior and posterior technique should be reserved for extended tumoral conditions where an anterior fixation does not offer enough stability or where more radical surgery is required. In the present series, immediate good spinal stabilization and neck pain relief was obtained in every case, allowing early mobilization. Improvement of the neurologic deficit was noted in 65% of our patients.

Adult↗
PubMed1993

Quantitative MR imaging of lumbar intervertebral disks and vertebral bodies: influence of diurnal water content variations.

The influence of diurnal water content variation on T1 and T2 and relative proton density (Nr) in intervertebral disks and vertebral bodies was studied in 10 healthy adult volunteers. T1, T2, and Nr were calculated from a set of 20 images obtained at 1.5 T with five single-section, multiecho sequences at different repetition times. Volunteers were randomized into study (one measurement in the morning and one in the evening) and control (two consecutive measurements in the morning) groups. In the study group, evening mean T1 and Nr in intervertebral disks and in vertebral bodies were significantly (P < .001) less than measured in the morning. Mean T2 in vertebral bodies significantly (P < .05) increased between morning and evening measurements. Diurnal variations were significantly less pronounced in degenerative than in normal intervertebral disks. No significant changes occurred in the control group. Relaxation time and Nr measurements allow sufficiently accurate estimation of diurnal water content variation in cohorts of vertebral bodies and intervertebral disks.

Adolescent↗
PubMed1992

Survivorship analysis of pedicular fixation systems in the treatment of degenerative disorders of the lumbar spine: a comparison of Cotrel-Dubousset instrumentation and the AO internal fixator.

We retrospectively analyzed the frequency and clinical consequences of pedicular fixation system failure in 50 patients who underwent Cotrel-Dubousset transpedicular instrumentation (CDI), and 46 patients who underwent AO internal fixator (IF) instrumentation for similar indications. After 2 years, 14 implants in the CDI group and 13 in the IF group had failed. The overall probability of implant survival was similar in both groups (CDI, 71.9% versus IF, 71.7%). However, more implant failures were associated with nonunion, loss of reduction, and nerve-root compromise in the IF group (four versus none) than in the CDI group. Implant failure usually occurred after solid fusion, and did not significantly affect the short-term clinical results. Therefore, implant failure does not a priori indicate failure of the operation.

Adolescent↗
PubMed1992

[Surgical treatment of spondylolisthesis with mild displacement by pedicular fixation and posterolateral fusion in adults].

Thirty-two consecutive adults with low-grade spondylolisthesis treated by stabilisation with the AO Internal Fixator and posterolateral fusion have been retrospectively reviewed with a mean follow-up time of 4 years (range, 24 to 71 months). There were 17 grade I and 15 grade II spondylolisthesis. Eight patients had degenerative and 24 patients had isthmic spondylolisthesis. An unisegmental fusion was performed in 4 cases, a bisegmental fusion in 25 cases and 3 patients had a multisegmental fusion. There was one deep infection and one nerve root compromise (3 per 100). Satisfactory results were achieved in 84 per 100 of the patients. There was non-union. This study suggests that transpedicular fixation and posterolateral fusion significantly enhances the rate of solid union to an extent which outweighs the risk of neurological complications due to the screw insertion. Fusion in situ in patients with low-grade spondylolisthesis is recommended as well as nerve root revision for all adults with concomitant radioculopathy. However, this review does not specifically support the use of the AO-internal fixator, but rather that of transpedicular fixation in general.

Adult↗
PubMed1992

[Technique of surgical correction of post-traumatic kyphosis].

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.

Adult↗
PubMed1991

Treatment of spondylolysis and spondylolisthesis with Cotrel-Dubousset instrumentation: a preliminary report.

We treated 50 consecutive patients with Cotrel-Dubousset instrumentation (CDI) for symptomatic spondylolisthesis. Average follow-up was 25 months. Fusion in situ was performed in 32 of 44 patients with mild spondylolisthesis, while 12 patients had reduction in conjunction with neural decompression. Two of six patients with severe spondylolisthesis who were treated via a single posterior approach had loss of reduction and nonunion. In another patient a Grade III spondylolisthesis could not be reduced via a posterior approach. Seventy-six percent of the patients had a good clinical result. The rate of solid fusion was 96%. One nerve root compromise recovered completely. One superficial wound infection healed uneventfully. This study suggests that combined anterior and posterior fusion is required for permanent and sufficient correction of severe spondylolisthesis even with CDI. Low-grade spondylolisthesis should be reduced only in conjunction with neural decompression.

Adolescent↗
PubMed1990

[Spinal metastases and metastasis-induced pathological fractures of the spine].

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.

Adult↗
PubMed1989

[The value of meniscus sonography of the knee joint].

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.

Adolescent↗
PubMed1989

[Results of locking intramedullary nailing in distal tibial shaft fractures].

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.

Adolescent↗
PubMedDate not supplied

[The internal fixator in nontraumatic indications in spinal surgery].

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.

Adolescent↗
PubMedDate not supplied

[Endoprosthetic management of tabes dorsalis arthropathy].

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.

Aged↗