The impact of clinical, morphological, psychosocial and work-related factors on the outcome of lumbar discectomy.

In a prospective controlled trial on 46 patients undergoing lumbar discectomy, three classes of variables (medical data including MRI-identified morphological abnormalities, general psychological factors and psychosocial aspects of work) were analyzed with regard to their predictive value for the outcome of lumbar disc surgery at 2 year follow-up. Multiple regression analyses were used to identify the best predictor variables of four different outcome measures (i.e. pain relief, reduction of disability in daily activities, return to work and surgical outcome). MRI-identified nerve root compromise and social support from the spouse were independent predictors of pain relief 2 years after surgery (R2 = 0.40, P < 0.01). Return to work 2 years after surgery was best predicted by depression and occupational mental stress (R2 = 0.36, P < 0.001). MRI-identified extent of herniation and depression were significant predictors of a good surgical outcome after lumbar discectomy (R2 = 0.61, P < 0.001). This study has demonstrated that the outcome of discectomy is critically dependent on which outcome variables are selected and that different sorts of predictor variables have a distinct influence on the various outcome variables. Obvious morphological alterations (i.e. disc extrusions, nerve root compromise) proved to be significant predictors of postoperative pain relief and improvement of disability in daily activities justifying a surgical treatment approach in these cases. The most important finding of this study was that return to work was not influenced by any clinical findings or MR-identified morphological alterations, but solely by psychological factors (i.e. depression) and psychological aspects of work (i.e. occupational mental stress).

Tissue characterization of symptomatic and asymptomatic disc herniations by quantitative magnetic resonance imaging.

The purpose of this investigation was to determine differences in tissue composition of symptomatic and asymptomatic disc herniations as reflected in T1 and T2 relaxation times (quantitative magnetic resonance imaging). Thirty patients with sciatica severe enough to require a discectomy and 46 asymptomatic volunteers (controls) were included in this study. Both groups had a clinical examination as well as a magnetic resonance investigation of the lumbar spine. The longitudinal and transverse magnetic relaxation times (T1 and T2, respectively) were calculated from a set of 20 images obtained with five single-slice/multi-echo sequences at different repetition time values on a commercial whole-body system (1.5 T). Twenty-two symptomatic and asymptomatic disc herniations could be matched according to age, gender, disc level, and the extent of herniation (protrusion or extrusion) and were compared with regard to T1 and T2 relaxation times. Symptomatic disc herniations exhibited significantly (pT1 < 0.04 and pT2 < 0.003) shorter T1 (delta T1: -182.1 milliseconds, -15%) and T2 (delta T2: -11.0 milliseconds, -21%) relaxation times than matched asymptomatic herniations. Symptomatic disc herniations also exhibited more advanced disc degeneration as graded by Pearce's criteria (p < 0.01). These results suggest that symptomatic and morphologically matched asymptomatic disc herniations differ with regard to disc matrix composition.

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

Natural history of individuals with asymptomatic disc abnormalities in magnetic resonance imaging: predictors of low back pain-related medical consultation and work incapacity.

STUDY DESIGN: Prospective study on individuals with asymptomatic lumbar disc abnormalities detected in magnetic resonance imaging. OBJECTIVES: To determine the natural history of asymptomatic disc abnormalities in magnetic resonance imaging and to identify predictors of future low back pain-related medical consultation and work incapacity. SUMMARY OF BACKGROUND DATA: The natural history of individuals with asymptomatic disc herniations has not been well established, but the high rate of lumbar disc alterations recently detected in asymptomatic individuals by magnetic resonance imaging demands reconsideration of a pathomorphology-based explanation of low back pain and sciatica. METHODS: Forty-six asymptomatic individuals who had a high rate of disc herniations (73%) were observed for an average of 5 years (range, 54-72 months). Four classes of variables (medical data including magnetic resonance imaging-identified disc abnormalities, general psychological factors, physical job characteristics, and psychosocial aspects of work) were assessed at baseline and follow-up. RESULTS: Disc herniations and neural compromise did not significantly worsen at follow-up, whereas disc degeneration progressed in 17 individuals (41.5%). Minor episodes of low back pain occurred in 19 individuals (41.3%), 6 of whom had to seek medical treatment and 5 of whom had to stop work temporarily. The requirement for low back pain-related medical consultation was predicted with high accuracy by listlessness, job satisfaction, and working in shifts (P < 0.001). Work incapacity was best predicted by physical job characteristics, job disaffection, and working in shifts (P < 0.01). CONCLUSION: Physical job characteristics and psychological aspects of work were more powerful than magnetic resonance imaging-identified disc abnormalities in predicting the need for low back pain-related medical consultation and the resultant work incapacity. However,the conclusions are still preliminary, and replication of the findings in larger and more representative study samples is needed.

Transformation of Vicia narbonensis via Agrobacterium-mediated gene transfer.

Shoot tips and epicotyl-segments of Vicia narbonensis were co-cultivated with Agrobacterium tumefaciens strain C58C1 pGV 3850 HPT, carrying a plasmid coding for hygromycin-phosphotransferase. On callus-induction medium containing 60 mg/l hygromycin for selection, approximately 18% of the explants produced hygromycin-resistant callus. After transfer to regeneration-medium these calluses produced hygromycin-resistant and nopaline-positive somatic embryos which could be regenerated to plantlets. The integration of the T-DNA into the plant genome was confirmed by Southern analysis.