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PubMed1999

Augmentation of an anterior solid rod construct with threaded cortical bone dowels. A biomechanical study.

STUDY DESIGN: This static, nondestructive, in vitro biomechanical study examines anterior solid rod construct stiffness following the addition of multilevel, threaded cortical bone dowels in a bovine model. A comparison is made with a clinically relevant posterior construct with and without an anterior release. OBJECTIVES: To determine if the addition of solid, multilevel disc space implants will increase construct rigidity, while maintaining or enhancing anterior column length. SUMMARY OF BACKGROUND DATA: Anterior instrumentation for thoracolumbar and lumbar scoliosis has achieved greater correction and preserved distal motion segments; however, kyphosis over the instrumented segments and nonunion have been observed more frequently than with posterior segmental spinal instrumentation. METHOD: Fifteen calf spines underwent mechanical testing. Group A (n = 7) included anterior constructs: 1) intact, 2) anterior release/rod/rib graft (L2-L5), and 3) anterior release/rod/dowels (L2-L5). Group B (n = 8) included posterior constructs: 1) intact, 2) posterior rod without anterior release (T13-L5), 3) posterior rod (T13-L5)/anterior release/rib graft (L2-L5). The protocol included axial compression (-600 N), axial rotation (+7 Nm), flexion/extension (+7.5 Nm), and lateral bending (+7.5 Nm). An anterior extensometer measured segmental displacements to calculate construct stiffness. Lateral radiographs evaluated alignment for the anterior constructs. Statistical analysis involved a one way analysis of variance (ANOVA) and a Student-Newman-Keuls post hoc test. RESULTS: All reconstructions restored stiffness to intact values with the exception of the dowels alone in axial rotation. The rod/dowel construct was stiffer than all other groups in axial compression, flexion/extension, and lateral bending, with the exception of the posterior rod without discectomy, which was superior in flexion and statistically similar in extension, lateral bending, and axial rotation. The anterior construct with rib graft was equivalent to the posterior construct with rib graft in all modes of testing. The dowels created greater lordosis than the bicortical rib grafts. CONCLUSIONS: Disc space augmentation increased stiffness except in axial rotation, in which values were restored to the intact level. Stiffness was superior to a clinically relevant posterior instrumentation comparison group following anterior release, and was equivalent to a posterior construct without anterior release except in anterior flexion. In addition, the implants enhanced lordosis. Increased rigidity should improve rates of arthrodesis, while maintenance of sagittal alignment may prevent pathologic compensatory curves in adjacent spinal segments. Further research is required to determine the optimal method of achieving structural interspace support.

Animals↗
PubMedDate not supplied

Daily coping practice predicts treatment effects in children with sickle cell disease.

OBJECTIVE: To examine the 1-month effects of a pain coping skills intervention in children with sickle cell disease (SCD). METHODS: Forty-six African American children (8-17 years old) were randomly assigned to either a coping skills condition or a standard care control condition. Children were asked to practice daily with audiotaped instructions of skills (e.g., relaxation, imagery). RESULTS: Multivariate analyses of summary measures indicated that children in the coping intervention (versus control group) reported a significantly more active approach to managing pain. Multilevel random effects models applied to daily diary data indicated that on pain days when children practiced their strategies, they had fewer health care contacts, fewer school absences, and less interference with household activities than on days when they did not practice. CONCLUSIONS: Brief training in coping skills followed by minimal therapist contact may lead to a range of benefits when children practice with their skills on a consistent basis.

Adaptation, Psychological↗
PubMed2005

Using administrative databases to measure waiting times for patients undergoing major cancer surgery in Ontario, 1993-2000.

PURPOSE: To determine how long patients in Ontario waited for major breast, colorectal, lung or prostate cancer surgery in the years 1993-2000. METHODS: "Surgical waiting time" was defined as the interval from date of preoperative surgeon consult to date of hospital admission for surgery. We created patient cohorts by linking appropriate diagnosis and procedure codes from Canadian Institutes of Health Information data. Scrambled unique surgeon identifiers were obtained from Ontario Health Insurance Plan data. Changes in median surgical waiting times were assessed with univariate time-trend analyses and multilevel models. Models were controlled for year of surgery and other patient (age, gender, comorbid conditions, income level, area of residence) and hospital level characteristics (teaching status, procedure volume status). RESULTS: Compared with 1993, median surgical waiting times in the year 2000 increased 36% for patients with breast cancer (to 19 d), 46% with colorectal (to 19 d), 36% with lung (to 34 d) and 4% with prostate cancer (to 83 d). Multilevel models confirmed significant increases in waiting times for all procedures. There were no concerning or consistent differences in waiting times among the categories of hospitals and patients examined. DISCUSSION: There were significant increases in surgical waiting times among patients undergoing breast, colorectal, lung or prostate cancer surgery in Ontario over years 1993-2000. Administrative databases can be used to efficiently measure such waits.

Breast Neoplasms↗
PubMed1975

An epidemiological model of the natural history of a disease within a multilevel care system.

Detailed epidemiological data on the entire course and treatment of illnesses requiring a variety of forms of management and various levels of institutionalization are scarce, probably due to the difficulty of assembling such data from a multiplicity of sources, particularly within complex and fragmented health care delivery systems. This paper described several analytic approaches to, and applications of, such a body of data, taken from a retrospective cohort study of 552 fractured hip cases incident in one year in an upstate New York county. Examples of six analytic applications of the data are presented, and emphasis is placed on the potential for practical use of some of the results.

Adolescent↗
PubMed2003

Urinary incontinence in subacute care--a retrospective analysis of clinical outcomes and costs.

OBJECTIVE: To investigate the effect of incontinence on clinical outcomes and costs for patients in subacute care. DESIGN: Retrospective analysis of data collected over a 3-month period in 1996. SETTING: 54 medical facilities in Australia and New Zealand providing subacute care in an inpatient setting. PATIENTS: 6773 episodes of care provided to 6455 rehabilitation and geriatric evaluation and management patients. MAIN OUTCOME MEASURES: Urinary continence status, treatment outcomes, length of stay, discharge destination, and nursing and allied healthcare costs. RESULTS: Discharge destination differed between incontinent and continent patients (57% compared with 82%, respectively, discharged home, and 29% compared with 12%, respectively, discharged to a nursing home or to further care). There was a difference in cost between patients who were continent and those who were incontinent throughout their episode of care (rehabilitation: $185.60 [95% CI, $181-$190] per day for incontinent and $156.82 [95% CI, $153-$160] for continent patients; and geriatric evaluation and management: $164.62 [95% CI, $157-$172] for incontinent and $121.40 [95% CI, $114-$129] for continent patients). However, multilevel analyses showed that, after allowing for age and level of functional independence, the contribution of continence status to the cost of care depended on the functional independence of the patient (cognitive function for orthopaedic patients [P < 0.01] and motor function for stroke patients [P = 0.04]). CONCLUSION: The relationship between continence status and cost of care is complex. However, the cost differences found in our study need to be considered in payment systems, allocation of staff levels on wards and in development of casemix classifications.

Aged↗
PubMedDate not supplied

Cluster effects and simultaneity in multilevel models.

For small group sizes, the GLS estimator in multilevel models is biased and inconsistent when the random cluster effects are correlated with the regressors. A fixed effects approach, conditioning on the cluster effects, provides consistent estimates for the slope parameters. The two estimators are equivalent when group sizes are large. The same results obtain for two-stage estimation procedures that allow for some of the regressors to be simultaneously determined with the dependent variable. The GLS and fixed effects estimators are applied to data on acute care hospital utilization in the UK, allowing for health authority district effects.

Effect Modifier, Epidemiologic↗
PubMed2003

Do life events have their effect on psychosis by influencing the emotional reactivity to daily life stress?

BACKGROUND: Life events (LE) have consistently been found to influence course and outcome of psychotic disorders. However, the mechanism through which they operate is not known. The present study investigated whether LE have their effect by impacting on the emotional sensitivity for daily hassles. METHOD: Patients with clinically remitted psychotic illness (N=42) were studied with the Experience Sampling Method (a structured diary technique assessing current context and mood in daily life) to assess: (1) appraised subjective stress related to daily events and activities; and (2) emotional reactivity conceptualized as changes in both negative affect (NA) and positive affect (PA). LE were assessed with the Brown & Harris Life Event and Difficulties Schedule. RESULTS: Multilevel regression analyses showed that previous exposure to LE influenced the appraised stressfulness of neither daily events nor the activities in which the subjects were involved. However, a history of LE did modify the emotional reaction to daily life stress, both in models predicting NA and in models predicting PA. CONCLUSIONS: By their cumulative effect on emotional reactivity to daily activities and events, LE may render individuals more vulnerable to the onset or persistence of psychotic experiences.

Adult↗
PubMed2005

Predictive fine granularity successive elimination for fast optimal block-matching motion estimation.

Given the number of checking points, the speed of block motion estimation depends on how fast the block matching is. In this paper, a new framework, fine granularity successive elimination (FGSE), is proposed for fast optimal block matching in motion estimation. The FGSE features providing a sequence of nondecreasing fine-grained boundary levels to reject a checking point using as little computation as possible, where block complexity is utilized to determine the order of partitioning larger sub-blocks into smaller subblocks in the creation of the fine-grained boundary levels. It is shown that the well-known successive elimination algorithm (SEA) and multilevel successive elimination algorithm (MSEA) are just two special cases in the FGSE framework. Moreover, in view that two adjacent checking points (blocks) share most of the block pixels with just one pixel shifting horizontally or vertically, we develop a scheme to predict the rejection level for a candidate by exploiting the correlation of matching errors between two adjacent checking points. The resulting predictive FGSE algorithm can further reduce computation load by skipping some redundant boundary levels. Experimental results are presented to verify substantial computational savings of the proposed algorithm in comparison with the SEA/MSEA.

Algorithms↗
PubMed2004

Comorbidity of pain problems and depressive symptoms in young women: results from a cross-sectional survey among women aged 15-24 in Hungary.

Frequent headaches and musculoskeletal pain problems were assessed as part of a cross-sectional health survey in a representative sample of 3615 young Hungarian women, aged 15-24 (mean age: 19.0 years). The representative sample was obtained by a multilevel stratified sampling procedure based on national statistical data, the refusal rate was 6%. Depressive symptomatology was assessed as well using the shortened form of the Beck Depression Inventory. The overall prevalence of frequent headaches was 43.8% in the sample, 25.8% of the investigated population reported chronic musculoskeletal pain problems. The co-prevalence rate of depression was significantly higher in the group of interviewees reporting pain problems, 11.2% in the group indicating frequent headaches (chi(2)=53.1, p<0.001), 10.3% in the group reporting musculoskeletal pain problems (chi(2)=12.4, p<0.001). In contrast, the prevalence of depressive symptomatology was 4.6% and 6.6% in the subgroups denying frequent headaches and musculoskeletal pain, respectively. The prevalence of chronic pain problems decreased with higher age, increased with the smaller size of residence and was lower in the non-student employment group, however, these differences across sociodemographic variables did not remain significant if tested by a multivariate logistic regression analysis. The high co-prevalence rates of depression in interviewees reporting chronic pain problem draws attention to the development of such secondary health problems and underscores the importance of early prevention. Epidemiological studies provide data for the better planning and management of prevention programs.

Adolescent↗
PubMed2004

Playful and rebellious states vs. negative affect in explaining the occurrence of temptations and lapses during smoking cessation.

Reversal theory constructs of playful and rebellious states are compared with negative affect as predictors of temptations and lapses and as predictors of three important correlates of resisting temptations to smoke: Cigarette availability, urge level, and coping during temptations. A total of 61 participants entered data in palmtop computers and tape recorders for the first 14 days of a cessation attempt. Multilevel, random-effects logistic regression analyses showed that fluctuations in playfulness, rebelliousness, negative affect, and cigarette availability all significantly discriminated temptations from nontemptations. Fluctuations in playfulness and rebelliousness, but not negative affect, significantly predicted being in situations where cigarettes were easily available. Fluctuations in playfulness, rebelliousness, and cigarette availability, but not urge levels or negative affect, significantly predicted coping during temptations, whereas coping, rebelliousness, cigarette availability, and urge levels predicted lapsing. Treatment and policy implications of these findings are discussed.

Adult↗
PubMed2000

Managed care and multilevel long-term care providers: reluctant partners.

Managed care is reshaping our health care system, although long-term care is only beginning to feel its effects. We report on the managed care involvement of 492 multilevel, long-term care facilities (MLFs; including skilled nursing and assisted/independent living) nationally. Organizational structure and culture and especially environmental characteristics are associated with whether facilities have contracts with managed care organizations (MCOs), plan to have contracts, are only gathering information on MCOs, or intend to do nothing in the near future. Resource dependence theory best explains MCO contracting patterns with MLFs appearing to be responding more to survival than to growth.

Aged↗
PubMed2004

The life situation and functional capacity of the elderly with locomotor disability in Sweden and Poland according to a model by Lawton.

A quadripartite concept, the Good Life for older people, was developed by the American psychologist M. P. Lawton and forms the theoretical framework of this study. Ninety Swedish and 93 Polish subjects, aged > or = 60 years who had reported locomotor disturbances in selected samples from the two countries, took part in the study. Interviews were performed using the Philadelphia Geriatric Center Multilevel Assessment Instrument (PGCMAI) and functional testing was done using the Standardized Practical Equipment (SPE). The Polish elderly scored lower in most domains of the PGCMAI, which meant a worse life situation according to the Good Life model. On the SPE, scoring was lower in the Polish group, mainly on items related to balance and mobility. There was a logic convergent validity between the PGCMAI and the SPE in the whole group. The somewhat more complicated life situation for the Polish elderly has to be further analysed.

Activities of Daily Living↗
PubMedDate not supplied

Developmental trajectories of externalizing behaviors in childhood and adolescence.

This article describes the average and group-based developmental trajectories of aggression, opposition, property violations, and status violations using parent reports of externalizing behaviors on a longitudinal multiple birth cohort study of 2,076 children aged 4 to 18 years. Trajectories were estimated from multilevel growth curve analyses and semiparametric mixture models. Overall, males showed higher levels of externalizing behavior than did females. Aggression, opposition, and property violations decreased on average, whereas status violations increased over time. Group-based trajectories followed the shape of the average curves at different levels and were similar for males and females. The trajectories found in this study provide a basis against which deviations from the expected developmental course can be identified and classified as deviant or nondeviant.

Adolescent↗
PubMed2000

The role of bone graft force in stabilizing the multilevel anterior cervical spine plate system.

STUDY DESIGN: The role of bone graft force in stabilizing an instrumented cervical spine was evaluated for one-level and three-level corpectomy models using in vitro experiments. OBJECTIVES: To investigate the role of bone graft force in enhancing stability of anterior cervical plate, and to study effects of fatigue loading. SUMMARY OF BACKGROUND DATA: The anterior cervical plate system is used widely in stabilizing the cervical spine after spinal corpectomy and grafting. Many factors such as applied screw torque, screw pullout force, plate strength, plate geometry, and type of bone graft have been studied. However, the role of bone graft in stabilizing the anterior plate system has not been explored. METHODS: Two models (one-level and three-level) incorporating corpectomy, strut graft, and anterior plate were constructed from eight human spine specimens (C2-T1). The flexibility of an intact specimen and two constructs with graft forces of 0 N and 100 N was determined. A flexibility test, simulating physiologic loads, consisted of pure moments of flexion, extension, lateral bending, and axial torques up to 1 Nm. For each moment, range of motion and neutral zone were determined. The stability potential index was defined as the decrease in motion caused by instrumentation, as compared with intact motion. A larger stability potential index indicates a more stable spinal construct. Repeated measures analysis of variance was used to determine the significant changes. RESULTS: In both models, bone graft force increased during extension, decreased during flexion, and showed minor changes during axial torsion and lateral bending. Higher bone graft force increased stability potential index-neutral zone and stability potential index-range of motion in the three-level model in all directions, but only in flexion-extension in the one-level model. Fatigue loading decreased bone graft force to a greater extent in the three-level model. CONCLUSIONS: In the corpectomy-graft-anterior-plate model, graft force decreased in flexion and increased in extension. Higher graft force increased and fatigue decreased stability of the spinal construct in the three-level model.

Adolescent↗
PubMedDate not supplied

Skip laminectomy--a new treatment for cervical spondylotic myelopathy, preserving bilateral muscular attachments to the spinous processes: a preliminary report.

BACKGROUND CONTEXT: Techniques in current use for expansive laminoplasty operations (ELAP) on the cervical spine damage the extensor mechanisms, resulting in restriction of neck motion, loss of lordosis and persistent axial pains. PURPOSE: This article introduces a new surgical technique called skip laminectomy, which reduces morbidity after decompression of the cervical spinal canal. STUDY DESIGN/SETTING: A prospective study is presented of all patients with multilevel cervical spondylotic myelopathy (CSM), treated by this new procedure between December 1998 and March 2000. PATIENT SAMPLE: Since December 1998, 61 patients with CSM have undergone the procedure, of whom 24 (13 men and 11 women) were selected for this study. Follow-up periods ranged from 12 to 25 months, with an average of 18 months. Average age at operation was 69 years (range, 50 to 82 years). Eighteen patients with CSM on whom C3-C7 open-door laminoplasties had been performed by the author before 1998 were selected as controls for study of postoperative atrophy of the deep extensor cervical muscles. There were 11 men and 7 women, average age 67 years (range, 45 to 81). OUTCOME MEASURES: Axial symptoms and Japanese Orthopaedic Association (JOA) scores were recorded. Pre- and postoperative ranges of neck motion were measured on lateral flexion and extension radiographs. Pre- and postoperative cervical curvature indexes were calculated according to Ishihara's method. For quantitative analysis of damage to the posterior cervical muscles, atrophy rates were calculated from cross-sectional areas of the deep extensor muscles on the pre- and postoperative axial magnetic resonance imaging. METHODS: In skip laminectomy, standard laminectomies are performed at selected levels, combined with partial laminectomies of the cephalad halves of laminae at other selected levels, where the muscular attachments to the spinous processes are left undisturbed. Instead of a standard laminectomy, an interlaminar decompression can be performed at levels where the anterior spinal cord compression is insignificant. It is accomplished by simply removing the cephalad half of the inferior lamina and ligamentum flavum without detaching the semispinalis cervicis and multifidus muscles from the adjacent spinous processes. RESULTS: Using JOA scores, the average recovery rate was 61.0%. None of the patients complained of persistent axial symptoms. The postoperative range of flexion-extension motion averaged 97% of the preoperative measures. The cervical curvature index was reduced in 1 of the 24 patients. The atrophy rate of the deep extensor muscles after skip laminectomy was 20% of that seen after open-door laminoplasty. CONCLUSIONS: Skip laminectomy for cervical spinal canal decompression is less invasive than conventional laminectomy and ELAP. It is effective in preventing postoperative problems, such as persistent axial symptoms, restriction of neck motion and loss of cervical lordosis.

Aged↗
PubMed1977

The principles and problems of evaluation.

A multilevel, multifocus approach to evaluation is proposed, using a complex community mental health center as a model. Goal attainment can be evaluated simultaneously from multiple perspectives at several points on the health care continuum, allowing for identification of relationships among diverse goals and for the involvement of varied people who have legitimate contributions to make toward the establishment of these goals. Allowing more people to participate in planning the programs they will ultimately implement, reduces certain barriers to initiating evaluation. The place of evaluation in the program and special skills of evaluators are also considered.

California↗
PubMed2006

Socioeconomic status, psychosocial processes, and perceived health: an interpersonal perspective.

BACKGROUND: Psychosocial variables, including stress, emotions, and social factors, may contribute to the association between socioeconomic status (SES) and health. Concepts and methods from interpersonal theory (1) could provide a useful framework for research concerning the roles of psychosocial factors in socioeconomic health disparities. PURPOSE: We examined the association between SES and psychosocial processes captured by the interpersonal circumplex and tested the degree to which circumplex ratings explained the association between SES and perceived health. METHODS: San Diego community residents (N = 304; 51% male; 34% Latino; 50% White; 20% Black; 6.8% Asian/Asian American; 2.9% another ethnicity) completed a circumplex-based assessment of several social contexts (home, work, and community), the SF-12 measure of perceived health, and questions concerning demographic characteristics. RESULTS: Multilevel models revealed that individuals with lower SES described their social worlds as more hostile and less friendly compared with their higher SES counterparts. Furthermore, lower SES was associated with perceptions of exposure to more dominant or controlling behavior from others, compared with higher SES. Appraisals of hostility versus friendliness, in particular, helped explain the inverse association between SES and some aspects of perceived health. CONCLUSIONS: Applications of interpersonal theory may be useful in efforts to understand the roles of psychosocial factors in SES-related health disparities.

Adult↗
PubMed2002

Risk factors for spinal epidural hematoma after spinal surgery.

STUDY DESIGN: A case-control retrospective analysis comparing patients who developed a postoperative spinal epidural hematoma with patients who did not develop this complication. OBJECTIVES: To identify risk factors for the development of an epidural hematoma following spinal surgery. SUMMARY OF BACKGROUND DATA: Neurologic deterioration following spinal surgery is a rare but devastating complication. Epidural hematomas should be suspected in the patient who demonstrates a new postoperative neurologic deficit. The risk factors that predispose a patient to a postoperative spinal epidural hematoma have not been identified. METHODS: Patients who underwent spinal surgery at a single institution over a 10-year period were retrospectively reviewed. Twelve patients who demonstrated neurologic deterioration after surgery and required surgical decompression because of an epidural hematoma were identified. All cases involved lumber laminectomies. A total of 404 consecutive patients that underwent lumbar decompression and did not develop an epidural hematoma formed the control group. Factors postulated to increase the risk of postoperative spinal epidural hematoma were compared between the two groups using logistic regression. RESULTS: Multilevel procedures (P = 0.037) and the presence of a preoperative coagulopathy (P < 0.001) were significant risk factors. Age, body mass index, perioperative durotomies, and postoperative drains were not statistically significant risk factors. CONCLUSIONS: Patients who require multilevel lumbar procedures and/or have a preoperative coagulopathy are at a significantly higher risk for developing a postoperative epidural hematoma.

Blood Coagulation Disorders↗