Priority setting in health care. Of course we should ask the tax payer.
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Health Care Rationing↗
Biomedical subjects
P Dolan
Publications and source records attributed to P Dolan.
Mechanical initiation of intervertebral disc degeneration.
STUDY DESIGN: Mechanical testing of cadaveric lumbar motion segments. OBJECTIVES: To test the hypothesis that minor damage to a vertebral body can lead to progressive disruption of the adjacent intervertebral disc. SUMMARY OF BACKGROUND DATA: Disc degeneration involves gross structural disruption as well as cell-mediated changes in matrix composition, but there is little evidence concerning which comes first. Comparatively minor damage to a vertebral body is known to decompress the adjacent discs, and this may adversely affect both structure and cell function in the disc. METHODS: In this study, 38 cadaveric lumbar motion segments (mean age, 51 years) were subjected to complex mechanical loading to simulate typical activities in vivo while the distribution of compressive stress in the disc matrix was measured using a pressure transducer mounted in a needle 1.3 mm in diameter. "Stress profiles" were repeated after a controlled compressive overload injury had reduced motion segment height by approximately 1%. Moderate repetitive loading, appropriate for the simulation of light manual labor, then was applied to the damaged specimens for approximately 4 hours, and stress profilometry was repeated a third time. Discs then were sectioned and photographed. RESULTS: Endplate damage reduced pressure in the adjacent nucleus pulposus by 25% +/- 27% and generated peaks of compressive stress in the anulus, usually posteriorly to the nucleus. Discs 50 to 70 years of age were affected the most. Repetitive loading further decompressed the nucleus and intensified stress concentrations in the anulus, especially in simulated lordotic postures. Sagittal plane sections of 15 of the discs showed an inwardly collapsing anulus in 9 discs, extreme outward bulging of the anulus in 11 discs, and complete radial fissures in 2 discs, 1 of which allowed posterior migration of nucleus pulposus. Comparisons with the results from tissue culture experiments indicated that the observed changes in matrix compressive stress would inhibit disc cell metabolism throughout the disc, and could lead to progressive deterioration of the matrix. CONCLUSIONS: Minor damage to a vertebral body endplate leads to progressive structural changes in the adjacent intervertebral discs.
Adult↗
Can exercise therapy improve the outcome of microdiscectomy?
STUDY DESIGN: A prospective randomized controlled trial of exercise therapy in patients who underwent microdiscectomy for prolapsed lumbar intervertebral disc. Results of a pilot study are presented. OBJECTIVE: To determine the effects of a postoperative exercise program on pain, disability, psychological status, and spinal function. SUMMARY OF BACKGROUND DATA: Microdiscectomy is often used successfully to treat prolapsed lumbar intervertebral disc. However, some patients do not have a good outcome and many continue to have low back pain. The reasons for this are unclear but impairment of back muscle function due to months of inactivity before surgery may be a contributing factor. A postoperative exercise program may improve outcome in such patients. METHODS: Twenty patients who underwent lumbar microdiscectomy were randomized into EXERCISE and CONTROL groups. After surgery, all patients received normal postoperative care that included advice from a physiotherapist about exercise and a return to normal activities. Six weeks after surgery, patients in the EXERCISE group undertook a 4-week exercise program that concentrated on improving strength and endurance of the back and abdominal muscles and mobility of the spine and hips. Assessments of spinal function were performed in all patients during the week before surgery and at 6, 10, 26, and 52 weeks after. The assessment included measures of posture, hip and lumbar mobility, back muscle endurance capacity and electromyographic measures of back muscle fatigue. On each occasion, patients completed questionnaires inquiring about pain, disability and psychological status. RESULTS: Surgery improved pain, disability, back muscle endurance capacity and hip and lumbar mobility in both groups of patients. After the exercise program, the EXERCISE group showed further improvements in these measures and also in electromyographic measures of back muscle fatigability. All these improvements were maintained 12 months after surgery. The only further improvement showed by the CONTROL group between 6 and 52 weeks was an increase in back muscle endurance capacity. CONCLUSION: A 4-week postoperative exercise program can improve pain, disability, and spinal function inpatients who undergo microdiscectomy. [Key words: electromyogram median frequency, exercise therapy, intervertebral disc prolapse, microdiscectomy, randomized controlled trial, spinal function.
Adolescent↗
Sudden and unexpected loading generates high forces on the lumbar spine.
STUDY DESIGN: A cross-sectional study of spinal loading in healthy volunteers. OBJECTIVES: To measure the bending and compressive forces acting on the lumbar spine, in a range of postures, when unknown loads are delivered unexpectedly to the hands. SUMMARY OF BACKGROUND DATA: Epidemiologic studies suggest that sudden and unexpected loading events often lead to back injuries. Such incidents have been shown to increase back muscle activity, but their effects on the compressive force and bending moment acting on the spine have not been fully quantified. Furthermore, previous investigations have focused on the upright posture only. METHODS: In this study, 12 volunteers each stood on a force plate while weights of 0, 2, 4, and 6 kg (for men, 40% less for women) were delivered into their hands in one of three ways: 1) by the volunteer holding an empty box with handles, into which an unknown weight was dropped; 2) by the same way as in 1, but with volunteer wearing a blindfold and earphones to eliminate sensory cues; or 3) by the volunteer sliding a box of unknown weight off a smooth table. Experiments were carried out with participants standing in upright, partially flexed, and moderately flexed postures. Spinal compression resulting from muscular activity was quantified using electromyographic signals recorded from the back and abdominal muscles. The axial inertial force acting up the long axis of the spine was calculated from the vertical ground reaction force. The bending moment acting on the osteoligamentous spine was quantified by comparing measurements of lumbar curvature with the bending stiffness properties of cadaveric lumbar spines. RESULTS: The contribution from abdominal muscle contraction to overall spinal compression was small (average, 8%), as was the axial inertial force (average, 2.5%), and both were highest in the upright posture. Peak bending moments were higher in flexed postures, but did not increase much at the moment of load delivery in any posture. Peak spinal compressive forces were increased by 30% to 70% when loads were suddenly and unexpectedly dropped into the box, and by 20% to 30% when they were slid off the table, as compared with loads simply held statically in the same posture (P < 0.001). The removal of audiovisual cues had little effect. CONCLUSIONS: Sudden and alarming events associated with manual handling cause a reflex overreaction of the back muscles, which substantially increases spine compressive loading. Manual handling regulations should aim to prevent such events and limit the weight of objects to be lifted.
Abdominal Muscles↗
Effects of backward bending on lumbar intervertebral discs. Relevance to physical therapy treatments for low back pain.
STUDY DESIGN: Mechanical testing of cadaveric motion segments. OBJECTIVES: To test the hypothesis that backward bending of the lumbar spine can reduce compressive stresses within lumbar intervertebral discs. SUMMARY OF BACKGROUND DATA: Lumbar extension affects the distribution of compressive stress inside normal cadaveric discs, but little is known about its effect on mechanically disrupted and degenerated discs. METHODS: Nineteen lumbar motion segments (mean donor age, 48 years) were subjected to complex mechanical loading to simulate the following postures: moderate lumbar flexion, 2 degrees of extension, 4 degrees of extension, and the neutral position (no bending). The distribution of compressive stress within the disc matrix was measured in each posture by pulling a miniature pressure transducer along the midsagittal diameter of the disc. Stress profiles were repeated after a mechanical treatment that was intended to simulate severe disc degeneration in vivo. RESULTS: The "degeneration" treatment reduced pressure in the nucleus pulposus and generated stress concentrations within the anulus, in a manner similar to that found in severely degenerated discs in vivo. When all discs were considered together, 2 degrees of extension increased the maximum compressive stress within the posterior anulus by an average of 16%, compared with the neutral posture. The size of localized stress peaks within the posterior anulus was increased by 43% (P = 0.02). In 4 degrees of extension, changes observed between 0 degree and 2 degrees were usually exaggerated. In contrast, moderate flexion tended to equalize the distribution of compressive stress. In 7 of the 19 discs, 2 degrees of lumbar extension decreased maximum compressive stress in the posterior anulus relative to the neutral posture by up to 40%. Linear regression showed that lumbar extension tended to reduce stresses in the posterior anulus in those discs that exhibited the lowest compressive stresses in the neutral posture (P = 0.003; R2 = 41%). CONCLUSIONS: The posterior anulus can be stress shielded by the neural arch in extended postures, but the effect is variable. This may explain why extension exercises can relieve low back pain in some patients.
Adult↗
A qualitative study of the extent to which health gain matters when choosing between groups of patients.
There is considerable debate about the appropriateness of allocating health care resources on the basis of the size of the health improvement that they generate. The aim of this study was to elicit the general public's views about the extent to which health gain matters vis-a-vis other considerations. A total of 60 respondents took part in group discussions designed to enable them to raise, discuss, and reflect upon, different arguments. The qualitative data showed that many responses were being generated by factors that were not directly included in the questions, and so it is difficult to meaningfully interpret the results of other studies which have asked similar questions but which have not looked at the reasons underlying the responses. However, a clear message did come through from the data; namely, that equality of access should prevail over the maximization of benefits. However, this was subject to the outcome constraint that treatments are sufficiently effective. An important question for future research, then is 'how effective do treatments have to be for the principle of equal access to apply?'
Adult↗
A note on QALYs versus HYEs. Health states versus health profiles.
This paper considers the question of what ought to be valued in the context of measuring the outcomes of healthcare interventions. The answer is discrete health states in the case of the quality-adjusted life-year (QALY) model and an entire health profile in the case of the healthy-years equivalent (HYE) approach. How well the weighted average of values attached to the former approximates the overall value attached to the latter depends on the validity of the assumptions of the QALY model. The paper considers some of the empirical literature relating to them. One of the most important assumptions, which from the limited evidence available appears not to hold, is additive separability. However, it is argued that violation of this assumption does not in itself invalidate the QALY approach, since in some circumstances it might be more appropriate to elicit the value of a health state independently of the states that succeed it. Investigation into this issue is identified as one of the key areas where future research efforts should be directed.
Health Status Indicators↗
Spinal position sense is independent of the magnitude of movement.
STUDY DESIGN: Position sense in the spine was recorded at T1, T7, L1, and S2 in three incremental angular ranges of flexion and on return to upright standing from these movements. OBJECTIVES: To determine the effect of angular range of movement on position sense. The main purpose was to establish a protocol for whole spine assessment of position sense in healthy and pathologic spines. SUMMARY OF BACKGROUND DATA: Position sense is one dimension of proprioception, classically assessed by the ability to reproduce preselected target positions. This approach was used in the current study to determine whether spinal position sense is affected by the magnitude of movement traversed in repositioning tasks. METHODS: Spinal position sense was assessed in 20 healthy subjects during repeated flexion movements carried out in one-third, half, and two thirds of the full range of movement in the sagittal and coronal planes. During each movement, the 3-Space Fastrak (Polhemus Inc., Colchester, VT) was used to record angular movement of the spine at four sensor locations (T1, T7, L1, and S2). The absolute difference in the sensor angles between repeated trials was calculated for each flexed position and on return to upright standing from these. These absolute differences were used as a measure of position sense. RESULTS: Absolute position sense after one-third angular movements was accurate to within 4.30 degrees +/- 2.84 degrees in flexed positions and 2.70 degrees +/- 2.20 degrees in upright postures. Corresponding results for two-thirds movements were 4.75 degrees +/- 2.63 degrees and 3.33 degrees +/- 2.60 degrees, respectively. Range of movement had no significant influence on the accuracy of position sense. CONCLUSIONS: 1) Healthy individuals are able to reposition their spine accurately under conditions of incremental increases in angular range. 2) Range-related variations in position sense are small and unlikely to be of clinical significance.
Adult↗
Principles of justice in health care rationing.
This paper compares and contrasts three different substantive (as opposed to procedural) principles of justice for making health care priority-setting or "rationing" decisions: need principles, maximising principles and egalitarian principles. The principles are compared by tracing out their implications for a hypothetical rationing decision involving four identified patients. This decision has been the subject of an empirical study of public opinion based on small-group discussions, which found that the public seem to support a pluralistic combination of all three kinds of rationing principle. In conclusion, it is suggested that there is room for further work by philosophers and others on the development of a coherent and pluralistic theory of health care rationing which accords with public opinions.
Decision Making↗
Effect of age on health state valuations.
OBJECTIVES: Valuations for health states defined by the EQ-5D measure of health-related quality of life, which were elicited using the time trade-off method, from a large sample of the UK general population have previously been shown to be related to the age of the respondent. This paper presents population valuation tariffs for all EQ-5D health states for those aged 18-59 and those aged 60 and over. METHODS: Health state valuations were elicited from a representative sample of over 3000 members of the UK general population using one-to-one interviews. The same regression technique which had previously been used to estimate the EQ-5D tariff for the whole population is used in the current analysis. Additional variables were created which were the product of the original variables and the dummy attached to the age group of the respondent. An earlier qualitative study had suggested that some of the observed differences in valuations might have resulted from more older respondents doubting the plausibility of the 'worse than dead' scenario. Therefore, the model was estimated both when the scores of those aged 60 and over were unmodified and when they were modified to account for this possibility. RESULTS: The tariff based on values from those aged 60 and over, was considerably lower than that based on values from those aged 18-59. When changes between health states were calculated, the difference could be as much as 0.15 on a scale between -1 and 1. However, when the scores of older respondents were adjusted, on the assumption that their lower values for states rated as worse than dead were due to an experimental artefact, the differences between the valuation tariffs of the two age groups greatly diminished. CONCLUSION: These results suggest that whose values are used may have an important effect on health state valuations, and in turn, therefore, on resource allocation decisions, but more research is needed to understand the source of the differences between the values given by different population subgroups.
Adolescent↗
Personal risk factors for first-time low back pain.
STUDY DESIGN: A prospective study of personal risk factors for first-time low back pain. OBJECTIVES: To construct and validate a multivariate model to predict low back pain. SUMMARY OF BACKGROUND DATA: Various physical and psychological factors have been reported to increase the risk of low back pain, but conflicting results may be attributable to inaccurate "clinical" measures and to poorly validated statistical models. METHODS: A total of 403 health care workers aged 18-40 years volunteered for the study. None had any history of "serious" back pain requiring medical attention or time off work. The volunteers completed the following questionnaires: the modified somatic perception questionnaire, the Zung depression scale, and the Health Locus of Control. Anthropometric factors were quantified using standard techniques. The 3Space Isotrak device (Polhemus, VT) was used to measure lumbar curvature and hip and lumbar spine mobility. Leg and back strength and back muscle fatiguability were measured in functional postures. Postal follow-up questionnaires, sent after 6, 12, 18, 24, 30, and 36 months, inquired about back pain, and multivariate logistic regression was used to identify risk factors at each follow-up. RESULTS: The response rate fell from 99% at 12 months to 90% at 36 months, at which time 90 volunteers reported "serious" back pain and 266 reported "any" back pain. The following were consistent predictors of serious back pain: reduced range of lumbar lateral bending, a long back, reduced lumbar lordosis, increased psychological distress, and previous nonserious low back pain. Only the latter three were consistent predictors of "any" back pain. Physical factors had the most influence in a sub-population of volunteers who were new to the job. CONCLUSIONS: Personal risk factors explained up to 12% of first-time low back pain.
Adolescent↗
Antimalarial, antiproliferative, and antitumor activities of artemisinin-derived, chemically robust, trioxane dimers.
Nine C-10 non-acetal derivatives of the natural trioxane artemisinin (1) were prepared as dimers using some novel chemistry. As designed, each dimer was stable chemically. C-10 Olefinic dimers 7 and C-10 saturated dimers 8-13 all showed good to excellent antimalarial and antiproliferative activities in vitro. Dimers 8, 10, and 12 were especially potent and selective at inhibiting growth of some human cancer cell lines in the NCI in vitro 60-cell line assay.
Animals↗
Conceptually new sulfone analogues of the hormone 1alpha, 25-dihydroxyvitamin D(3): synthesis and preliminary biological evaluation.
A conceptually new series of vitamin D(3)-like nonfluorinated and fluorinated 16-ene side chain tert-butyl sulfones 3-7 has been synthesized. Even though these novel C,D-ring side chain analogues of the hormone 1alpha,25-dihydroxyvitamin D(3) (1,1,25D(3)) lack a terminal OH group, thought previously to be essential for high biological activity, they are highly antiproliferative and, in several cases, transcriptionally active in vitro but desirably noncalcemic in vivo. The side chain sulfone group may be binding to the nVDR as a hydrogen-bond acceptor, in contrast to the hydrogen-bond donor function of the 25-OH group of natural 1,25D(3).
Animals↗
Advice given to patients with fractures. Drug treatments that reduce fracture rate are underused after vertebral fractures.
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Humans↗
Effect of discussion and deliberation on the public's views of priority setting in health care: focus group study.
OBJECTIVE: To investigate the extent to which people change their views about priority setting in health care as a result of discussion and deliberation. DESIGN: A random sample of patients from two urban general practices was invited to attend two focus group meetings, a fortnight apart. SETTING: North Yorkshire Health Authority. SUBJECTS: 60 randomly chosen patients meeting in 10 groups of five to seven people. MAIN OUTCOME MEASURES: Differences between people's views at the start of the first meeting and at the end of the second meeting, after they have had an opportunity for discussion and deliberation, measured by questionnaires at the start of the first meeting and the end of the second meeting. RESULTS: Respondents became more reticent about the role that their views should play in determining priorities and more sympathetic to the role that healthcare managers play. About a half of respondents initially wanted to give lower priority to smokers, heavy drinkers, and illegal drug users, but after discussion many no longer wished to discriminate against these people. CONCLUSION: The public's views about setting priorities in health care are systematically different when they have been given an opportunity to discuss the issues. If the considered opinions of the general public are required, surveys that do not allow respondents time or opportunity for reflection may be of doubtful value.
Adolescent↗
Dynamic forces acting on the lumbar spine during manual handling. Can they be estimated using electromyographic techniques alone?
STUDY DESIGN: Compressive loading of the lumbar spine was analyzed using electromyographic, movement analysis, and force-plate techniques. OBJECTIVES: To evaluate the inertial forces that cannot be detected by electromyographic techniques alone. SUMMARY OF BACKGROUND DATA: Links between back pain and manual labor have stimulated attempts to measure spine compressive loading. However, direct measurements of intradiscal pressure are too invasive, and force plates too cumbersome for use in the workplace. Electromyographic techniques are noninvasive and portable, but ignore certain inertial forces. METHODS: Eight men lifted boxes weighing 6.7 and 15.7 kg from the ground, while joint moments acting about L5-S1 were quantified 1) by using a linked-segment model to analyze data from Kistler force plates and a Vicon movement-analysis system, and 2) by measuring the electromyographic activity of the erector spinae muscles, correcting it for contraction speed and comparing it to moment generation during static contractions. The linked-segment model was used to calculate the "axial thrust," defined as the component of the L5-S1 reaction force that acts along the axis of the spine and that is unrelated to trunk muscle activity or static body weight. RESULTS: Peak extensor moments predicted by the two techniques were similar and equivalent to spinal compressive forces of 2.9-4.8 kN. The axial thrust "hidden" from the electromyographic technique was negligible during slow lifts, and remained below 4% of peak spinal compression even during fast heavy lifts. Peak axial thrust was proportional to the peak vertical ground reaction (R2 = 0.74). CONCLUSIONS: Electromyographic techniques can measure dynamic spinal loading, but additional force-plate data would improve accuracy slightly during lifts requiring a vigorous upward thrust from the legs.
Adult↗
US and UK health economics: a reply to Joe Newhouse's paper.
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Communication Barriers↗
Health-related quality of life of Colles' fracture patients.
Recent guidelines published by the National Osteoporosis Foundation (NOF) make extensive use of quality-adjusted life-years (QALYs). Crucial to these guidelines, therefore, are the assumptions that are made about the health-related quality of life (HRQoL) gained from the avoidance of osteoporotic fractures. This paper reports on a study in which 50 Colles' fracture patients were asked to describe their health at each visit during treatment using the EuroQol descriptive system and to value their own health using the visual analogue scale (VAS). By applying a set of population-derived valuations to the states reported by the patients, the QALY loss is shown to be about 2%. This is about half of the loss, based upon clinician judgement, that is contained in the NOF guidelines. In addition, the results suggest that it may be possible to use VAS scores to predict treatment requirements, since those patients who require fewer visits have, on average, higher initial VAS scores.
Aged↗