Anterior lumbar interbody fusion. A minimum 10-year follow-up.

STUDY DESIGN: One hundred eight patients from a consecutive series of 125 anterior lumbar interbody fusions were invited to take part in a clinical outcome assessment (including plain radiography and magnetic resonance imaging of the lumbosacral spine) more than 10 years after the original surgery. OBJECTIVES: By standardizing the reporting of outcome, to determine whether the duration of patient follow-up influences the outcome of surgery, with particular reference to the effects of compensation and psychological status. SUMMARY OF BACKGROUND DATA: The success rates of lumbar spinal fusion surgery reported in the literature vary widely. The lack of standardization of measures of patient outcome limits the value of study comparisons. Evaluation of the efficacy of spinal fusion is further compounded by the adverse effects of both compensation and psychological disturbance on the reporting of outcome. METHODS: One hundred three patients agreed to take part in a clinical outcome assessment by completing a comprehensive low-back questionnaire that included demographic, compensation, and employment details. Eighty-seven of these cases also agreed to undergo radiographic evaluation and magnetic resonance imaging of the lumbar spine. Subjective assessment of outcome was based on a 10-point analog pain scale as well as patient opinion regarding the success of surgery. A more objective assessment of outcome was made using the Low-Back Outcome Score. Psychological status was determined by combining the Modified Somatic Perception Questionnaire and the Zung Depression Scale. The effects of radiologic fusion, compensation status, psychological status, and reoperation on the various outcome measures were assessed and compared with the results reported in a separate but similar series of patients with a minimum follow-up of 2 years. RESULTS: Seventy-eight percent of patients rated themselves as having "complete relief" or "a good deal of relief," but only 34% fell into the "excellent" or "good" category using the Low-Back Outcome Score. The clinical outcome was not associated with the presence of radiologic fusion and was not influenced by the compensation status. Psychological disturbance at review and reoperation, however, did influence the reporting of outcome and were significantly correlated with the Low-Back Outcome Score. With the exception of the effects of compensation, these results were remarkably similar to the findings in the 2-year study. CONCLUSIONS: The findings of the study suggest that the assessment of outcome of lumbar interbody fusion is strongly compounded by the psychological make-up of the patient and that this effect is maintained in the long term. However, the negative effect of compensation observed at 2 years seems to dissipate with time and becomes insignificant at 10 years.

Clinical practice guidelines. Particular reference to the management of pain in the lumbosacral spine.

Clinical practice guidelines and protocols are a seductive way of trying to improve the standard of clinical practice. If these are to be most effective, they must evaluate rigorously the evidence supporting a particular management strategy and make appropriate recommendations based on this information. This process needs to be objective, should engage and obtain endorsement from the disciplines that are involved in providing the care, and be accompanied by appropriate implementation strategies. Subsequently, the impact of these strategies should be measured. Existing guidelines for the management of lumbosacral pain largely conform to criteria for guidelines development. It can therefore be expected that they will benefit practitioners and the community.

Chemonucleolysis.

Even with a history of controversy and troubling complications, chymopapain has endured the test of time to show 30 years of clinical success in the treatment of herniated nucleus pulposus. Strict attention to indications, contraindications, and technique ensures safety and efficacy of treatment. A trend to decreased dosage may result in less postinjection spasm. Between 1982-1991, 121 adverse events in 135,000 patients were reported to the Food and Drug Administration and investigated. Seven cases of fatal anaphylaxis, 24 infections, 32 bleeding problems, 32 neurologic events, and 15 miscellaneous occurrences were found. Overall mortality rate was 0.019%. All categories were of lesser incidence than complications with laminectomy. Long-term results show that improvement after chemonucleolysis is maintained, whereas the outcome after laminectomy is reported to deteriorate with time. Cost savings with chemonucleolysis over laminectomy are largely a matter of shorter hospitalization. A protocol for cervical chemonucleolysis is being developed in the United States after good results have been shown in Spain and France. Other enzymes continue under investigation, but chymopapain remains the standard to which they are compared.

Magnetic resonance imaging assessment of disc degeneration 10 years after anterior lumbar interbody fusion.

STUDY DESIGN: One-hundred-eight patients from a consecutive series of 125 anterior lumbar interbody fusions were invited to participate in a radiographic and magnetic resonance imaging assessment more than 10 years after the original surgery. OBJECTIVE: The aim of this study was to determine the long-term incidence of disc degeneration adjacent to an anterior interbody fusion and to determine whether this was influenced by the length of the fusion. SUMMARY OF BACKGROUND DATA: Biomechanical studies in human cadaver spines support the view that fusion in the lumbar spine is likely to be associated with an increased incidence of degeneration at adjacent levels, but there is little reliable information on the incidence of juxtafusion degeneration from the few long-term studies of lumbar spine fusion reported in the literature. METHODS: Eighty-seven patients agreed to take part in the study, but in six cases the magnetic resonance imaging procedure had to be abandoned. Of the 81 patients who underwent both radiographic assessment and magnetic resonance imaging scanning, preoperative discography had demonstrated a normal disc above the level of the fusion in 52. This group of patients formed the basis of this report. Each sequence of magnetic resonance imaging films was examined by one radiologist. The signal strength was assessed on T2-weighted images in the sagittal plane and disc morphology was assessed on T1- and T2-weighted sagittal and T1-weighted axial images. Fusion status was assessed on the plain films and magnetic resonance imaging. RESULTS: The incidence of a normal adjacent intervertebral disc in cases of solid fusions to the sacrum was 68%. This was not influenced by the length of the fusion. CONCLUSION: The findings of this study suggest that degeneration after an anterior lumbar interbody fusion is determined more by individual characteristics than by the fusion itself.

Anterior lumbar fusion. A comparison of noncompensation patients with compensation patients.

One hundred fifty-one patients had an anterior interbody lumbar spinal fusion for intractable back pain. A solid bony fusion was obtained in 76% of the patients. Of patients unemployed before surgery, 50% had returned to work at review. Sixty-eight percent of patients rated themselves as significantly improved by the procedure. Posterior distraction instrumentation neither increased the rate of union nor improved the final results. Compensation status and psychological disturbance at presentation were significant prognostic factors. Psychological disturbance at review had a profound effect on the outcome and patient satisfaction ratings. It is recommended that in future studies compensation status and psychological disturbances are explicitly included in the outcome statistics.

Assessment of spinal cord blood flow and function in sheep after anterolateral cervical interbody fusion in the presence of cord damage.

The safety of an anterolateral cervical fusion, which facilitates stabilization without sacrifice of the anterior longitudinal ligament, recently has been brought into question. The purpose of this study was to assess the effect of an anterolateral cervical fusion on spinal cord blood flow and motor and sensory-evoked potentials in the presence of an incomplete spinal cord injury. In 12 sheep, a spinal cord injury was produced by the rapid inflation of an extradural balloon catheter; six of the animals had a cervical fusion. There was no significant difference in spinal cord blood flow or evoked potential responses obtained from the sheep that had an anterolateral cervical fusion, compared with the sheep that did not. Based on these results, it seems unlikely that this surgery has an adverse effect on recovery from spinal cord injury in the absence of operative mishap.

Anterior lumbar fusion: results, assessment techniques and prognostic factors.

One hundred and fifty-one patients underwent anterior interbody lumbar spinal fusion for intractable back pain. A solid bony fusion was obtained in 76%. The method of outcome assessment profoundly affected the results; whereas 68% of patients rated themselves as significantly improved by the procedure, only 40% achieved a good or excellent result on the more objective low-back outcome score. Patients who underwent a second procedure did not do well, and "salvage" surgery is not recommended. Posterior distraction instrumentation neither increased the rate of union nor improved the final results. The rate of fusion was influenced by the presence of a compensation claim. Compensation status and psychological disturbance at presentation were significant prognostic factors. Psychological disturbance at review had a profound effect on the outcome and patient satisfaction ratings. It is recommended that future studies employ a recognised outcome score and that the analysis specifically includes compensation status and psychological disturbance.

Economic impact of HIV infection and coronary heart disease in immigrants to Canada.

OBJECTIVE: To compare the direct health care costs of illnesses associated with the human immunodeficiency virus (HIV) and of coronary heart disease (CHD) in immigrants to Canada. DESIGN: Comparative cost analysis. PARTICIPANTS: All people who immigrated to Canada in 1988. The numbers with HIV infection and CHD were estimated from country-specific HIV seroprevalence data and national CHD mortality statistics and data from the Framingham study. Health care costs, projected over the 10 years after immigration, were calculated on the basis of data from the Hospital Medical Records Institute and provincial fee schedules. RESULTS: Of the 161,929 immigrants in 1988, 484 were estimated to be HIV positive. The total cost of treatment of HIV-related illnesses from 1989 to 1998 (discounted at 3%) would be $18.5 million: $17.1 million would be spent on the outpatient and inpatient care of the HIV-positive immigrants, $1.0 million on care of the subsequently infected sexual partners and $0.4 million on care of the HIV-positive children born to seropositive immigrant women. In comparison, CHD would develop in 2558 immigrants during the same 10-year period. The total CHD costs would be $21.6 million: $8.4 million would be spent on treating myocardial infarction, $3.2 million on coronary artery bypass grafting, $1.6 million on pacemaker insertion and $8.4 million on treating other CHD events. CONCLUSIONS: The economic impact of HIV infection in immigrants to Canada is similar to that of CHD. This comparison identifies an important shortcoming in current immigration policy: economic considerations can be arbitrarily applied to certain diseases, thereby discriminating against specific groups of immigrants.

Assessment of outcome in patients with low-back pain.

The Low-Back Outcome Score has been devised as a new and accurate rating system for patients with low-back pain. Thirteen factors, such as pain, employment, sporting ability, rest required, and activities of daily living, were included; subjective opinion was excluded. Pain and active pursuits were weighted. Presentation of the score as a questionnaire, excluding examination findings, eliminated both interobserver variation and observer variation with time. The score was applied retrospectively in a follow-up study of conservatively treated patients and was found to be more comprehensive and more discriminating than the Oswestry Disability Score, the Waddell Disability Rating, or the Waddell Physical Impairment Rating. The Low-Back Outcome Score is recommended for further evaluation in future prospective studies in low-back pain.

HIV antibody screening among immigrants: a cost-benefit analysis.

To assess the economic impact of HIV (human immunodeficiency virus) antibody screening among potential immigrants on Canada's health care system we estimated the costs and benefits of such screening among the 160 135 immigrants who entered Canada in 1988 using the in-hospital costs of treating AIDS (acquired immune deficiency syndrome) over the 10 years after immigration. This economic model was based on current international HIV seroprevalence data, Canadian immigration statistics and estimates of disease progression. Between 343 and 862 of the immigrants were estimated to have been HIV seropositive; with the use of the enzyme-linked immunosorbent assay and the Western blot technique 310 to 780 of them would have been correctly identified as being seropositive, and 33 to 82 would have been incorrectly classified as being seronegative. Another 16 would have been falsely classified as being seropositive. There would have been 151 to 379 cases of AIDS from 1988 to 1998 among the immigrants identified as being HIV-positive. The estimated total cost of screening would have been $3.3 to $3.4 million. The in-hospital costs of treating HIV-infected immigrants in whom AIDS developed between 1989 and 1998 would have been $5.0 to $17.1 million. Accordingly, screening would have saved $1.7 to $13.7 million over the 10 years after immigration. However, we do not advocate screening on the basis of economic analysis alone and acknowledge that any policy regarding such screening must also incorporate social, legal and ethical considerations.

The effects of compensation on recovery from low-back injury.

The influence of compensation on recovery from low-back pain was assessed in a retrospective controlled cohort study. One hundred fifty compensable and 150 noncompensable back injury patients were invited for review between 1 and 5 years from presentation. A 91.3% follow-up was achieved, and there was no difference in the median age, follow-up, and initial injury score between the two groups. The incidence of reported pain, disability, psychological disturbance, unemployment, and length of time off work was greater in the compensation group (P less than 0.001). Settlement of the claim did not result in any reduction in morbidity, even up to 5 years later. These results demonstrate that the payment of compensation delays recovery from low-back injury.