Showing papers in "Spine in 1999"

New in vivo measurements of pressures in the intervertebral disc in daily life.

Abstract: Study design We conducted intradiscal pressure measurements with one volunteer performing various activities normally found in daily life, sports, and spinal therapy. Objectives The goal of this study was to measure intradiscal pressure to complement earlier data from Nachemson with dynamic and long-term measurements over a broad range of activities. Summary of background data Loading of the spine still is not well understood. The most important in vivo data are from pioneering intradiscal pressure measurements recorded by Nachemson during the 1960s. Since that time, there have been few data to corroborate or dispute those findings. Methods Under sterile surgical conditions, a pressure transducer with a diameter of 1.5 mm was implanted in the nucleus pulposus of a nondegenerated L4-L5 disc of a male volunteer 45-years-old and weighing 70 kg. Pressure was recorded with a telemetry system during a period of approximately 24 hours for various lying positions; sitting positions in a chair, in an armchair, and on a pezziball (ergonomic sitting ball); during sneezing, laughing, walking, jogging, stair climbing, load lifting during hydration over 7 hours of sleeping, and others. Results The following values and more were measured: lying prone, 0.1 MPa; lying laterally, 0.12 MPa; relaxed standing, 0.5 MPa; standing flexed forward, 1.1 MPa; sitting unsupported, 0.46 MPa; sitting with maximum flexion, 0.83 MPa; nonchalant sitting, 0.3 MPa; and lifting a 20-kg weight with round flexed back, 2.3 MPa; with flexed knees, 1.7 MPa; and close to the body, 1.1 MPa. During the night, pressure increased from 0.1 to 0.24 MPa. Conclusions Good correlation was found with Nachemson's data during many exercises, with the exception of the comparison of standing and sitting or of the various lying positions. Notwithstanding the limitations related to the single-subject design of this study, these differences may be explained by the different transducers used. It can be cautiously concluded that the intradiscal pressure during sitting may in fact be less than that in erect standing, that muscle activity increases pressure, that constantly changing position is important to promote flow of fluid (nutrition) to the disc, and that many of the physiotherapy methods studied are valid, but a number of them should be re-evaluated.

In vivo intradiscal pressure measurement in healthy individuals and in patients with ongoing back problems.

Abstract: Study design In vivo intradiscal pressure measurement in different postures in healthy individuals and in those with ongoing back problems. Objectives With the most recent technique, 1) to analyze the influence of degeneration on the intradiscal pressure, 2) to calculate the spinal load on the L4-L5 intervertebral discs, and 3) to assess the relation between the spinal load and movement of the intervertebral motion segment. Summary of background data Almost all the data on intradiscal pressure are from the studies by Nachemson. The results from these pioneering studies have formed the basis for current knowledge about the in vivo loading conditions of the human spine. Although performed already during the 1960s and 1970s with the technique available at that time, virtually no other similar studies have been performed to corroborate the findings. Methods The intradiscal pressure (vertical and horizontal) was measured using an advanced pressure sensor in 8 healthy volunteers and 28 patients with ongoing low back pain, sciatica, or both at L4-L5. Among other calculations, the actual loading conditions in various body positions were calculated in relation to the angle between the two vertebrae of the studied motion segments. Results The effect of respiration on intradiscal pressure was shown as a continuously periodic fluctuation in the healthy prone individual. The intradiscal pressure was significantly reduced according to the degree of disc degeneration as estimated by magnetic resonance imaging. There possibly was a difference between the vertical and horizontal pressures in the degenerated and nondegenerated discs because the nucleus pulposus was pressure-tropic property. The spinal load increased in the following order of body positions: prone, 144 N; lateral, 240 N; upright standing, 800 N; and upright sitting, 996N (P Conclusions The spinal load was highly dependent on the angle of the motion segment in normal discs in vivo. The intradiscal pressure in degenerated discs was significantly reduced compared with that of normal discs. However, further studies on the effect of respiratory movement on intradiscal pressure, the difference between vertical and the horizontal pressures, and the difference in the spinal load between standing and the sitting body positions are necessary. The data obtained from the current study are fundamental to understanding the pathomechanisms and biomechanical problems of disc disease.

Information and advice to patients with back pain can have a positive effect. A randomized controlled trial of a novel educational booklet in primary care.

Abstract: Study Design. A double-blind, randomized controlled trial of a novel educational booklet compared with a traditional booklet for patients seeking treatment in primary care for acute or recurrent low back pain. Objective. To test the impact of a novel educational booklet on patients' beliefs about back pain and functional outcome. Summary of Background Data. The information and advice that health professionals give to patients may be important in health care intervention, but there is little scientific evidence of their effectiveness. A novel patient educational booklet, The Back Book, has been developed to provide evidence-based information and advice consistent with current clinical guidelines. Methods. One hundred sixty-two patients were given either the experimental booklet or a traditional booklet. The main outcomes studied were fear-avoidance beliefs about physical activity, beliefs about the inevitable consequences of back trouble, the Roland Disability Questionnaire, and visual analogue pain scales. Postal follow-up response at 1 year after initial treatment was 78%. Results. Patients receiving the experimental booklet showed a statistically significant greater early improvement in beliefs which was maintained at 1 year. A greater proportion of patients with an initially high fear-avoidance beliefs score who received the experimental booklet had clinically important improvement in fear-avoidance beliefs about physical activity at 2 weeks, followed by a clinically important improvement in the Roland Disability Questionnaire score at 3 months. There was no effect on pain. Conclusion. This trial shows that carefully selected and presented information and advice about back pain can have a positive effect on patients' beliefs and clinical outcomes, and suggests that a study of clinically important effects in individual patients may provide further insights into the management of low back pain. Nonspecific low back pain is a common and recurring symptom that most people usually deal with themselves and for which there is no effective cure. Hence, the information and advice that health professionals give to patients may be a potent element of the health care intervention. Von Korff and Saunders 36 and Bush et al 12 found that one of the main reasons patients consult physicians is to seek information and reassurance. Bush et al 12 suggested that these patients have practical and realistic desires to learn about their low back pain, what to expect, and what they can do about it. There is some evidence that greater congruence among the patient's and clinician's perception of the problem, the prognosis for the disorder, and its long-term management is associated with higher patient satisfaction and better short-term outcomes. 14 Qualitative studies 8,33 have demonstrated the complexity and heterogeneity of patients' perceptions of back pain, which may raise questions about how easily these can be modified by simple information and advice. Deyo and Diehl 18 and Bush et al 12 found that, for patients in the United States, the most frequent reason for dissatisfaction with medical care was failure to receive an adequate explanation of their back pain. Patients who believed that the physician's explanation was inadequate wanted more diagnostic tests, did not cooperate as well with treatment, and had poorer clinical outcomes at 3 weeks. Skelton et al 33 found that patients in the United Kingdom were skeptical of medical explanations for their back pain either because they doubted its validity or because it did not fit their own understanding of the problem. Borkan et al 8 found that Israeli patients also were quite critical of the medical system and more interested in what works. The first U.S. and U.K. clinical guidelines for acute low back pain 3,16 recommended that patients should be given accurate and up-to-date information and advice about back pain and its management; however, that recommendation was based on theoretical considerations and general clinical consensus rather than on any firm scientific evidence that such information improves outcomes. These guidelines gave few practical details on precisely what the content of that information and advice should be, apart from general reassurance about the absence of serious disease and that most back pain improves quickly with simple symptomatic measures and activity modification. There has been a progressive shift in subsequent international guidelines. 10 Based on additional evidence that is now available, 40 the more recent U.K. 31 and New Zealand 2 guidelines suggest that the physician provide more positive advice to stay active and continue ordinary activities as normally as possible. The New Zealand guidelines also provide a detailed assessment of psychosocial yellow flags (risk factors for chronic pain and disability) and suggest general behavioral principles for how patients with these features should be managed. 23 Discussion at the Second International Forum for Primary Care Research on Low Back Pain 9 identified the continuing need for a simple and convincing explanation of back pain that is acceptable to patients and that would form a logical basis for active management. Most guidelines recommend that printed educational material should be made available, though this recommendation is based on limited evidence. 10 There are hundreds of leaflets and booklets about back pain, but remarkably few have been submitted to any sort of scientific evaluation. 11 Roland and Dixon 28 reported on the only randomized controlled trial (RCT) of a traditional clinical booklet that showed any significant impact on patients: those receiving the booklet consulted less frequently and had fewer specialist referrals for back pain over the next year. Cherkin et al 15 reported on an RCT that compared a 15-minute session with an educational nurse with a booklet that was similar to the material accompanying the Agency for Health Care Policy and Research (AHCPR) guidelines. 3 The nurse intervention yielded higher patient satisfaction, perceived knowledge, and exercise participation in the short term. The booklet showed similar trends, but they did not reach statistical significance compared with the outcomes of usual care. Neither of these trials showed any effect of a booklet on pain or functional status. The aim of the current study was to determine the impact of a novel educational booklet on the beliefs and functional outcome of patients seeking treatment in primary care for an acute or recurrent episode of low back pain.

Randomized trial of radiofrequency lumbar facet denervation for chronic low back pain.

Abstract: Study Design. A prospective double-blind randomized trial in 31 patients. Objectives. To assess the clinical efficacy of percutaneous radiofrequency denervation of the lumbar zygapophysial joints in reducing pain, functional disability, and physical impairment in patients with back pain originating from the lumbar zygapophysial joints. Summary of Background Data. Chronic low back pain is a major health problem in the industrialized world. A treatment option is percutaneous radiofrequency denervation of the lumbar zygapophysial joints. Its clinical elficacy has never been formally tested in a controlled trial. Methods. Thirty-one patients with a history of at least 1 year of chronic low back pain were selected on the basis of a positive response to a diagnostic nerve blockade and subsequently randomly assigned to one of two treatment groups. Each patient in the radiofreguency treatment group (15 patients) received an 80 C radiofrequency lesion of the dorsal ramus of the segmental nerve roots L3, L4, and L5. Patients in the control group (n = 16) underwent an the same procedure but without use of a radiofrequency current. Both the treating physician and the patients were blinded to the group assignment. Before treatment, physical impairment, rating of pain, the degree of disability, and quality of life were assessed by a blinded investigator. Results. Eight weeks after treatment there were 10 success patients in the radiofrequency group (n = 15) and 6 in the sham group (n = 16), The unadjusted odds ratio was 3.3 (P = 0.05, not significant), and the adjusted odds ratio was 4.8 (P < 0.05, significant). The differences in effect on the visual analog scale scores, global perceived effect, and the Oswestry disability scale were statistically significant. Three, 6, and 12 months after treatment, there were significantly more success patients in the radiofrequency group compared with the sham group. Conclusions. Radiofrequency lumbar zygapophysial joint denervation results in a significant alleviation of pain and functional disability in a select group of patients with chronic low back pain, both on a short-term and a long-term basis.

A follower load increases the load-carrying capacity of the lumbar spine in compression

Abstract: Study Design. An experimental approach was used to test human cadaveric spine specimens. Objective. To assess the response of the whole lumbar spine to a compressive follower load whose path approximates the tangent to the curve of the lumbar spine. of Background Data. Compression on the lumbar spine is 1000 N for standing and walking and is higher during lifting. Ex vivo experiments show it buckles at 80-100 N. Differences between maximum ex vivo and in vivo loads have not been satisfactorily explained. Methods. A new experimental technique was developed for applying a compressive follower load of physiologic magnitudes up to 1200 N. The experimental technique applied loads that minimized the internal shear forces and bending moments, made the resultant internal force compressive, and caused the load path to approximate the tangent to the curve of the lumbar spine. Results. A compressive vertical load applied in the neutral lordotic and forward-flexed postures caused large changes in lumbar lordosis at small load magnitudes. The specimen approached its extension or flexion limits at a vertical load of 100 N. in sharp contrast, the lumbar spine supported a load of up to 1200 N without damage or instability when the load path was tangent to the spinal curve. Conclusions. Until this study, an experimental technique for applying compressive loads of in vivo magnitudes to the whole lumbar spine was unavailable. The load-carrying capacity of the lumbar spine sharply increased under a compressive follower load, as long as the load path remained within a small range around the centers of rotation of the lumbar segments. The follower load path provides an explanation of how the whole lumbar spine can be lordotic and yet resist large compressive loads. This study may have impiications for determining the role of trunk muscles in stabilizing the lumbar spine.

Results of the Scoliosis Research Society instrument for evaluation of surgical outcome in adolescent idiopathic scoliosis : a multicenter study of 244 patients

Abstract: STUDY DESIGN An outcome questionnaire was constructed to evaluate patient satisfaction and performance and to discriminate among patients with adolescent idiopathic scoliosis. OBJECTIVES To determine reliability and validity in a new quality-of-life instrument for measuring progress among scoliosis patients. SUMMARY OF BACKGROUND DATA Meta-analysis of the surgical treatment of adolescent idiopathic scoliosis determined that a uniform assessment of outcome did not exist. In addition, patient measures of well-being as opposed to process measures (e.g., radiographs) were not consistently reported. This established the need for a standardized questionnaire to assess patient measures in conjunction with process measures. METHODS The instrument consists of 24 questions divided into seven equally weighted domains as determined by factor analysis: pain, general self-image, postoperative self-image, general function, overall level of activity, postoperative function, and satisfaction. The questionnaire takes approximately 5 minutes to complete and is taken at predetermined time intervals. A total of 244 of patients from three different sites responded to the questionnaire. RESULTS The reliability based on internal consistency was confirmed with a Cronbach's alpha coefficient greater than 0.6 for each domain. In addition, acceptable correlation coefficient values greater than 0.68 were obtained for each domain by the test-retest method on normal controls. Similarly; to establish validity of the questionnaire, responses of normal high school students were compared with that of the patients. Consistent differences were noted in the domains between the two groups with P < 0.003. The largest differences were in pain (control, 29.96 +/- 0.20; patient, 13.23 +/- 5.55) and general level of activity (control, 14.96 +/- 0.20; patient, 12.16 +/- 3.23). Examination of the relationship between the domains and patient satisfaction showed that pain correlates with satisfaction to the greatest degree (Pearson's correlation co-efficient, r = -0.511; P < 0.001), followed by self-image (r = 0.412; P < 0.001). CONCLUSIONS This questionnaire addresses patient measures for evaluation of outcome in adolescent idiopathic scoliosis surgery by examining several domains. It also allows for dynamic monitoring of scoliosis patients as they become adults. This is a validated instrument with good reliability measures.

The Cochrane review of surgery for lumbar disc prolapse and degenerative lumbar spondylosis.

Abstract: Study Design. A Cochrane review of randomized controlled trials. Objectives. To collate the scientific evidence on surgical management for lumbar disc prolapse and degenerative lumbar spondylosis. Summary of Background Data. Surgical investigations and interventions account for as much as one third of the health care costs for spinal disorders, but the scientific evidence for most procedures still is unclear. Methods. A highly sensitive search strategy identified all published randomized controlled trials. Cochrane methodology was used for meta-analysis of the results. Results. Twenty-six randomized controlled trials of surgery for lumbar disc prolapse and 14 trials of surgery for degenerative lumbar spondylosis were identified. Methodologic weaknesses were found in many of the trials. Only one trial directly compared discectomy and conservative management. Meta-analyses showed that surgical discectomy produces better clinical outcomes than chemonucleolysis, which is better than placebo. Three trials showed no difference in clinical outcomes between microdiscectomy and standard discectomy, but in three other studies, both produced better results than percutaneous discectomy. Three trials showed that inserting an interposition membrane after discectomy does not significantly reduce scar formation or alter clinical outcomes. Five heterogeneous trials on spinal stenosis and degenerative spondylolisthesis permit very limited conclusions. There were nine trials of instrumented versus noninstrumented fusion: Meta-analysis showed that instrumentation may facilitate fusion but does not improve clinical outcomes. Conclusions. There is now strong evidence on the relative effectiveness of surgical discectomy versus chemonucleolysis versus placebo. There is considerable evidence on the clinical effectiveness of discectomy for carefully selected patients with sciatica caused by lumbar disc prolapse that fails to resolve with conservative management. There is no scientific evidence on the effectiveness of any form of surgical decompression or fusion for degenerative lumbar spondylosis compared with natural history, placebo, or conservative management. The Cochrane reviews will be updated continuously as other trials become available.

Modulation of the biologic activity of the rabbit intervertebral disc by gene therapy: an in vivo study of adenovirus-mediated transfer of the human transforming growth factor beta 1 encoding gene.

Abstract: STUDY DESIGN In vivo studies using a rabbit model to determine the biologic effects of direct, adenovirus-mediated transfer of a therapeutic gene to the intervertebral disc. OBJECTIVES 1) To deliver an exogenous therapeutic gene to rabbit lumbar intervertebral discs in vivo, 2) to quantify the resulting amount of gene expression, and 3) to determine the effect on the biologic activity of the discs. SUMMARY OF BACKGROUND DATA Although growth factors such as transforming growth factor beta 1 appear to have promising therapeutic properties, there currently is no practical method for sustained delivery of exogenous growth factors to the disc for the management of certain chronic types of disease (e.g., disc degeneration). A possible solution is to modify the disc cells genetically through gene transfer such that the cells manufacture the desired growth factors endogenously on a continuous basis. METHODS Saline, with or without virus, was injected directly into lumbar discs of 22 skeletally mature female New Zealand white rabbits. Group 1 (n = 11) received the adenovirus construct Ad/CMV-hTGF beta 1 containing the therapeutic human transforming growth factor beta 1-encoding gene. Group 2 (n = 6) received adenovirus containing the luciferase marker gene. Group 3 (n = 5) received saline only. The rabbits were killed 1 week after injection. Immunohistochemical staining for human transforming growth factor beta 1 was performed on the disc tissues of one rabbit from Group 1. Nucleus pulposus tissues from the remaining rabbits were cultured in serumless medium. Bioassays were performed to determine human transforming growth factor beta 1 production and proteoglycan synthesis. RESULTS Discs injected with Ad/CMV-hTGF beta 1 exhibited extensive and intense positive immunostaining for transforming growth factor beta 1. The nucleus pulposus tissues from the discs injected with Ad/CMV-hTGF beta 1 exhibited a 30-fold increase in active transforming growth factor beta 1 production, and a 5-fold increase in total (active + latent) transforming growth factor beta 1 production over that from intact control discs (P < 0.05). Furthermore, these tissues exhibited a 100% increase in proteoglycan synthesis compared with intact control tissue, which was statistically significant (P < 0.05). CONCLUSIONS The results of this study suggest that the intervertebral disc is an appropriate site for adenovirus-mediated transfer of exogenous genes and subsequent production of therapeutic growth factors. Gene therapy therefore may have useful applications for study of the basic science of the intervertebral disc and for clinical management of degenerative disc disease.

Serial changes in trunk muscle performance after posterior lumbar surgery.

Abstract: Study Design. Serial changes in trunk muscle performance were prospectively studied in 20 patients who underwent posterior lumbar surgery. Objective. To evaluate the influence of back muscle injury on postoperative trunk muscle performance and low back pain, to clarify the significance of minimization of back muscle injury during surgery. of Background Data. The current investigators have reported examination of iatrogenic back muscle injury in an animal model and in humans. However, definite impairment caused by such back muscle injury has not been clarified. Methods. The patients were divided into a short-retraction-time group (<80 minutes; n = 12) and a long- retraction-time group (≥80 minutes; n = 8). Before surgery and 3 and 6 months after surgery, the degree of back muscle injury was estimated by magnetic resonance imaging, and trunk muscle strength was measured. In addition, the incidence and severity of low back pain were serially analyzed. Results. Back muscle injury was directly related to the muscle retraction time during surgery. The damage to the multifidus muscle was more severe, and the recovery of extensor muscle strength was delayed in the long-retraction-time group. In addition, the incidence of postoperative low back pain was significantly higher in the long-retraction-time group. Conclusions. Postoperative trunk muscle performance is dependent on the muscle retraction time. Thus, it is beneficial to shorten the retraction time to minimize back muscle injury and subsequent postoperative low back pain.

Strain on intervertebral discs after anterior cervical decompression and fusion.

Abstract: STUDY DESIGN An analysis of the change in strain distribution of intervertebral discs present after anterior cervical decompression and fusion by an original method. The analytical results were compared to occurrence of herniation of the intervertebral disc on magnetic resonance imaging. OBJECTIVES To elucidate the influence of anterior cervical decompression and fusion on the unfused segments of the spine. SUMMARY OF BACKGROUND DATA There is no consensus regarding the exact significance of the biomechanical change in the unfused segment present after surgery. METHODS Ninety-six patients subjected to anterior cervical decompression and fusion for herniation of intervertebral discs were examined. Shear strain and longitudinal strain of intervertebral discs were analyzed on pre- and postoperative lateral dynamic routine radiography of the cervical spine. Thirty of the 96 patients were examined by magnetic resonance imaging before and after surgery, and the relation between alteration in strains and postsurgical occurrence of disc herniation was examined. RESULTS In the cases of double- or triple-level fusion, shear strain of adjacent segments had increased 20% on average 1 year after surgery. Thirteen intervertebral discs that had an abnormally high degree of strain showed an increase in longitudinal strain after surgery. Eleven (85%) of the 13 discs that showed an abnormal increase in longitudinal strain had herniation in the same intervertebral discs with compression of the spinal cord during the follow-up period. Relief of symptoms was significantly poor in the patients with recent herniation. CONCLUSIONS Close attention should be paid to long-term biomechanical changes in the unfused segment.

A randomized clinical trial of three active therapies for chronic low back pain.

Abstract: Study design A randomized clinical trial. Objectives To examine the relative efficacy of three active therapies for chronic low back pain. Summary of background data There is much evidence documenting the efficacy of exercise in the conservative management of chronic low back pain, but many questions remain regarding its exact prescription and method of application. The most successful method must be identified to enable refinement of future rehabilitation programs to target the specific needs of the patient with chronic low back pain and the budget of the healthcare provider. Methods One hundred forty-eight patients with chronic low back pain were randomized to one of the following treatments, which they attended twice a week for 3 months: 1) modern active physiotherapy, 2) muscle reconditioning on training devices, or 3) low-impact aerobics. Pretherapy and posttherapy, objective measurements of lumbar mobility were performed, and questionnaires were administered inquiring about self-rated pain and disability, and psychosocial factors. Similar questionnaires were administered 6 months after therapy. The data were analyzed using the intention-to-treat principle. Results Of the 148 patients, 16 (10.8%) dropped out of the therapy. One hundred thirty-seven questionnaires (93%) were available for analysis at all three time points. After therapy, significant reductions were observed in pain intensity, frequency, and disability; Fear-Avoidance Beliefs about physical activity (FABQactivity); and "praying/hoping," "catastrophizing," and "pain behavior" coping strategies--each with no group differences in the extent of the response. These effects were maintained over the subsequent 6 months, with the exception of disability and FABQactivity for the physiotherapy group. There were small but significant posttherapy increases in lumbar mobility, with aerobics and devices showing a greater response than physiotherapy. Conclusion The general lack of treatment specificity suggests that the main effects of the therapies were educed not through the reversal of physical weaknesses targeted by the corresponding exercise modality, but rather through some "central" effect, perhaps involving an adjustment of perception in relation to pain and disability. The direct costs associated with administering physiotherapy were three times as great, and devices four times as great, as those for aerobics. Administration of aerobics as an efficacious therapy for chronic low back pain has the potential to relieve some of the huge financial burden associated with the condition.

Predictors of surgical outcome in degenerative lumbar spinal stenosis.

Abstract: Study design A prospective, observational study. Objectives To identify outcome predictors of surgery for degenerative lumbar spinal stenosis. Summary of background data Degenerative lumbar spinal stenosis is the most frequent indication for spine surgery in the elderly. More than 25% of surgical patients have a poor outcome, yet little is known about factors that predict the outcome of surgery. Methods Surgery was performed on 199 patients with degenerative lumbar spinal stenosis, and they were observed for 2 years after surgery in four referral centers. Surgery consisted of decompressive laminectomy with or without arthrodesis. Outcomes included validated measures of symptom severity, walking capacity, and satisfaction with the results of surgery. Potential predictors of outcome included sociodemographic factors and physical examination, as well as radiographic, psychological, social, and clinical history variables. Results The proportion of patients with severe pain decreased from 81% before surgery to 31% by 2 years afterward. The most powerful preoperation predictor of greater walking capacity, milder symptoms, and greater satisfaction was the patient's report of good or excellent health before surgery. Low cardiovascular comorbidity also predicted a favorable outcome. Conclusions Patient's assessments of their own health and comorbidity are the most cogent outcome predictors of surgery for spinal stenosis.

The prevalence of low back pain in the elderly. A systematic review of the literature.

Abstract: Study Design. The prevalence of low back pain in the older population (≥ 65 years) was reviewed in an analysis of the literature from 1966 to the present. Objective. To determine the prevalence of low back pain in the geriatric population. Summary of Background Data. Back pain is one of the most frequently reported conditions affecting the adult population. However, the prevalence of low back pain in the older age population is not accurately known. Methods. A methodologic search of five computerized bibliographic databases was performed to identify citations on the prevalence of low back pain in the elderly. Data were summarized, and prevalence studies were critically appraised in detail for their quality. Results. There is wide variability in the reported prevalence of back pain. Many factors have been proposed to explain these findings including sample source, study design, definitions of back pain, and use of patient-reported data. Comorbidity among older patients also contributes to the variability in the reporting of prevalence of back Dain. Conclusion. There is an under-representation of the older population in the back pain literature. The data in the current study suggest that the prevalence of low back pain in this population is not known with certainty and is not comparable with that in the younger population. The authors stress the need for future studies to improve the reporting of age information to make prevalence studies more informative and applicable.

The reliability and validity of the Biering-Sorensen test in asymptomatic subjects and subjects reporting current or previous nonspecific low back pain.

Abstract: Study design A reliability study and case-control study were conducted. Objectives To determine the reliability and discriminative validity of the Biering-Sorensen test. Summary of background data A low Biering-Sorensen score has been found to predict who will have nonspecific low back pain. However, the reliability of the test remains controversial, implying that some studies may have produced results that underestimated the magnitude of the predictive validity of this test. Methods Two raters measured the time holding a specific position (holding time) of 63 subjects (23 currently experiencing nonspecific low back pain, 20 who had had an episode, and 20 who were asymptomatic) while they performed the Biering-Sorensen test twice, 15 minutes apart. A standardized protocol was followed. Test-retest reliability was evaluated by calculating intra-class correlation coefficients (ICC 1,1), 95% confidence intervals (CI), and standard errors of the measurement (SEM) for the total group and for the subgroups. A three-way analysis of variance was used to determine whether test order, subject gender, or symptom status affected holding time. Results High reliability indices were obtained for the Biering-Sorensen test in subjects with current nonspecific low back pain (ICC [1,1], 0.88; 95% CI, 0.73-0.95; SEM, 11.6 seconds), in subjects who had had nonspecific low back pain (ICC [1,1], 0.77; 95% CI, 0.52-0.90; SEM, 17.5 seconds), and in asymptomatic subjects (ICC [1,1], 0.83; 95% CI, 0.62-0.93; SEM, 17.4 seconds). Results of an analysis of variance showed that subjects asymptomatic for low back pain had a significantly longer holding time than the other two groups (P Conclusions The Biering-Sorensen test provides reliable measures of position-holding time and can discriminate between subjects with and without nonspecific low back pain.

The effect of lumbar fatigue on the ability to sense a change in lumbar position. A controlled study.

Abstract: STUDY DESIGN A cross-sectional study in patients with recurrent/chronic low back trouble and healthy control subjects. OBJECTIVE To evaluate the effect of paraspinal muscle fatigue on the ability to sense a change in lumbar position. SUMMARY OF BACKGROUND DATA Protection against spinal injury requires proper anticipation of events, appropriate sensation of body position, and reasonable muscular responses. Lumbar fatigue is known to delay lumbar muscle responses to sudden loads. It is not known whether the delay is because of failure in the sensation of position, output of the response, or both. METHODS Altogether, 106 subjects (57 patients with low back trouble [27 men and 30 women] and 49 healthy control subjects [28 men and 21 women]) participated in the study. Their ability to sense a change in lumbar position while seated on a special trunk rotation unit was assessed. A motor rotated the seat with an angular velocity of 1 degree per second. The task in the test involved reacting to the perception of lumbar movement (rotation) by releasing a button with a finger movement. The test was performed twice, before and immediately after a fatiguing procedure. During the endurance task, the participants performed upper trunk repetitive extensions against a resistance, with a movement amplitude adjusted between 25 degrees flexion and 5 degrees extension, until exhaustion. RESULTS Patients with chronic low back trouble had significantly poorer ability than control subjects on the average to sense a change in lumbar position (P = 0.007), which was noticed before and after the fatiguing procedure. Lumbar fatigue induced significant impairment in the sensation of position change (P < 0.000001). CONCLUSIONS Lumbar fatigue impairs the ability to sense a change in lumbar position. This feature was found in patients and control subjects, but patients with low back trouble had poorer ability to sense a change in lumbar position than control subjects even when they were not fatigued. There seems to be a period after a fatiguing task during which the available information on lumbar position and its changes is inaccurate.

Complications and predictive factors for the successful treatment of flatback deformity (fixed sagittal imbalance).

Abstract: STUDY DESIGN This is an analysis of consecutive cases of flatback deformity (fixed sagittal imbalance), treated by one of two surgeons at a university hospital. OBJECTIVE To define factors that contribute to results with treatment of flatback syndrome, classify types of sagittal deformities, and discuss complications. SUMMARY OF BACKGROUND DATA There are few reports that detail the results and complications of current instrumentation and osteotomy techniques for correction of fixed sagittal deformities. METHODS Twenty-eight patients treated with osteotomies for sagittal imbalance were eligible for 2-year minimum follow-up (average, 3.6 years). Patients were classified (segmental imbalance, Type 1; or global imbalance, Type 2) and evaluated by upright radiographs, chart review, and a questionnaire. RESULTS Twenty-eight (100%) patients returned the questionnaire, and 28 had current radiographs. Five treatment groups were evaluated based on osteotomy type (anterior, posterior [Smith-Petersen], both, or pedicle subtraction) and use of anterior structural grafting. All patients were treated with modern bilateral hook-rod-screw constructs. Mean correction at the osteotomy levels was 25 degrees for Type 1 deformities and 30 degrees for Type 2 (P < 0.05). Sagittal correction averaged 6.6 cm in Type 2 deformities (P < 0.05). Questionnaire analysis showed a significant and persistent reduction in subjective pain level. There were seven patients with 11 total complications and no neurologic deficits. Associations among patients who were not satisfied with their results (n = 4) included insufficient sagittal correction (P = 0.045), pseudarthrosis (P = 0.045), coronal imbalance, and four or more medical comorbidities (P = 0.03). CONCLUSIONS Satisfaction with the results of treatment may be reduced in patients with four or more major co-existent medical problems, insufficient sagittal correction, and resultant pseudarthrosis.

Comparison of anterior and posterior instrumentation for correction of adolescent thoracic idiopathic scoliosis.

Abstract: Study Design. This was a prospective study of two cohort groups of patients (one group receiving anterior instrumentation and the other posterior instrumentation) receiving treatment for thoracic idiopathic scoliosis. Objective. To present the 2-year postoperative results of a prospective multicenter study comparing the use of anterior instrumentation with that of posterior multisegmented hook instrumentation for the correction of adolescent thoracic idiopathic scoliosis. of Background Data. Despite reports of satisfactory results, problems have been reported with posterior systems, including worsening of the lumbar curve after surgery and failure to correct hypokyphosis. Theoretically. the advantages of anterior instrumentation include prevention of lumbar curve decompensation by shortening the convexity of the thoracic curve. In addition, by removing the disc, better correction of thoracic hypokyphosis could be obtained. Methods. Seventy-eight patients who underwent an anterior spinal fusion using flexible threaded rods and nuts (Harms-MOSS instrumentation, De Puy-Motecn-Acromed, Cleveiand, OH) were analyzed and compared with 100 patients who underwent posterior spinal fusion with multisegmented hook systems. Parameters of comparison included coronal and sagittal correction, balance, distal lumbar fusion levels, and complications. All patients had idiopathic thoracic curves of King Types II to V. The average age at surgery was 14 years in each group, the average preoperative curve 57°, and the minimum duration of follow-up for all patients 24 months. All data were collected prospectively and analyzed via Epi Info statistical analysis (Centers for Disease Control, Atlanta, GA), Results. Average coronal correction of the main thoracic curve was 58% in the anterior group and 59% in the posterior group (P - 0.92). Analysis of sagittal contour showed that the posterior systems failed to correct a preoperative hypokyphosis (sagittal T5 to T12 less than 20°) in 60% of cases, whereas 81% were normal postoperatively in the anterior group. However, hyperkyphosis (sagittal T5 to T12 greater than 40°) occurred after surgery in 40% of the anterior group when the preoperative kyphosis was greater than 20°. Postoperative coronal balance was equal in both groups. An average of 2.5 (range, 0-6) distal fusion leveis were saved using the anterior spinal instrumentation according to the criteria used for determining posterior fusion levels in this study. Selective fusion of the thoracic curve (distal fusion level T11, T12, L1) was performed in 76 of 78 patients (97%) in the anterior group as compared with only 18 of 100 (18%) in the posterior group. Surgically confirmed pseudarthrosis occurred in 4 of 78 patients (5%) in the anterior group and in 1 of 100 patients (1%) in the posterior group (P = 0.10). Loss of correction greater than 10° occurred in 18 of 78 patients (23%) in the anterior group and in 12 of 100 patients (12%) in the posterior group (P 0.01). Implant breakage occurred in 24 patients (31%) of the anterior group and in only 1 patient (1%) of the posterior group.

Personal risk factors for first-time low back pain.

Abstract: 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

Biomechanical efficacy of unipedicular versus bipedicular vertebroplasty for the management of osteoporotic compression fractures.

Abstract: Study design Cadaveric study on the biomechanics of osteoporotic vertebral bodies augmented and not augmented with polymethylmethacrylate cement. Objectives To determine the strength and stiffness of osteoporotic vertebral bodies subjected to compression fractures and 1) not augmented, 2) augmented with unipedicular injection of cement, or 3) augmented with bipedicular injection of cement. Summary of background data Percutaneous vertebroplasty is a relatively new method of managing osteoporotic compression fractures, but it lacks biomechanical confirmation. Methods Fresh vertebral bodies (L2-L5) were harvested from 10 osteoporotic spines (T scores range, -3.7 to -8.8) and compressed in a materials testing machine to determine intact strength and stiffness. They were then repaired using a transpedicular injection of cement (unipedicular or bipedicular), or they were unaugmented and recrushed. Results Results suggest that unipedicular and bipedicular cement injection restored vertebral body stiffness to intact values, whereas unaugmented vertebral bodies were significantly more compliant than either injected or intact vertebral bodies. Vertebral bodies injected with cement (both bipedicular and unipedicular) were significantly stronger than the intact vertebral bodies, whereas unaugmented vertebral bodies were significantly weaker. There was no significant difference in loss in vertebral body height between any of the augmentation groups. Conclusions This study suggests that unipedicular and bipedicular injection of cement, as used during percutaneous vertebroplasty, increases acute strength and restores stiffness of vertebral bodies with compression fractures.

Complication, survival rates, and risk factors of surgery for metastatic disease of the spine

Abstract: Study design The risk factors for complications and complication and survival rates in patients with metastatic disease of the spine were reviewed. A retrospective study was performed. Objectives To determine the surgical complication and survival rates of patients with metastatic disease of the spine and risk factors for complication occurrence. Summary of background data The role of surgical intervention for patients with metastatic disease of the spine has been controversial. Several risk factors for surgical complications have been identified. Short survival times and high complication rates have failed to justify surgical intervention in many cases. Methods Patients (n = 80) undergoing surgical treatment for metastatic disease of the spine were reviewed. Surgical indications included progressive neurologic deficit, neurologic deficit failing to respond to, or progressing after, radiation treatment; intractable pain; radioresistant tumors; or the need for histologic diagnosis. Patients underwent anterior, posterior, or combined decompression and stabilization procedures. Neurologic examination was recorded before surgery, postoperative period, and at least follow-up. Complication and survival rates were calculated. Several variables were examined for risk of complication. Results The mean age at time of surgery was 55.6 years (range, 20-84 years). Mean survival time after the diagnosis of spinal metastasis was 26.0 months (range, 1-107.25 months). Mean survival time after surgery was 15.9 months (range, 0.25-55.5 months). Sixty-five patients showed no change in Frankel grade, 19 improved one Frankel grade, and 1 deteriorated one Frankel grade; 1 patient had paraplegia. Thirty-five complications occurred in 20 patients (25.0%). Ten patients (12.5%) had multiple complications accounting for 23 of the 35 postoperative problems (65.7%). Sixty patients had no surgical complications (75%). There were no intraoperative deaths. Conclusions The likelihood that a complication occurred was significantly related to Harrington classifications demonstrating significant neurologic deficits and the use of preoperative radiation therapy. In general, Harrington classifications with neurologic deficits and lower Frankel grades before and after surgery were associated with an increased risk of complication. Overall, the major complication rate was relatively low, and minor complications were successfully treated with minimal morbidity. The relatively long survival time after spinal surgery in this group of patients justifies surgical treatment for metastatic disease. Most complications occurred in a small percentage of patients. To minimize complications, patients must be carefully selected based on expected length of survival, the use of radiation therapy, presence of neurologic deficit, and impending spinal instability or collapse caused by bone destruction.

Management of nonspecific low back pain by physiotherapists in Britain and Ireland. A descriptive questionnaire of current clinical practice.

Abstract: Study Design. A descriptive questionnaire of chartered physiotherapists. Objective. To investigate current physiotherapeutic management of low back pain throughout Britain and Ireland. Summary of Background Data. Physiotherapists play a key role in low back pain management. Although clinical guidelines for best practice have been developed recently, there has been no large-scale attempt to describe current physiotherapeutic treatment approaches with in Britain or Ireland. Methods. After semi-structured interviews (n = 6) and two pilot studies (n = 77) were done, postal questionnaires were distributed to four regional cluster samples of the membership of two physiotherapy professional organizations (n = 2654). After two mailings, a random sample of 90 nonresponders were followed up. Data were analyzed using the Statistical Package for the Social Sciences (SPSS Ltd., Woking, Surrey, UK), and precision of the survey estimates was assessed by calculation of sampling errors and intraclass correlation coefficients for cluster sampling. Results. Results were received from 1548 therapists (total response rate, 58.3%); of these, 813 reported that they were practicing in settings in which they treated patients with low back pain. Analysis of the results indicated the overall popularity of the Maitland mobilization and McKenzie approaches among physiotherapists. Although exercise per se was mentioned frequently by respondents, a marked difference in opinion among therapists regarding the optimal type of exercise for low back pain was obvious. Little evidence was demonstrated of the use of manipulation, fitness programs, or multidisciplinary efforts involving behavioral and physical aspects of treatment. Commonly used methods of electrotherapy were interferential therapy, ultrasound, pulsed short-wave diathermy, and transcutaneous electrical nerve stimulation. Conclusions. The results of this study emphasize the need to evaluate further and improve the dissemination of findings regarding the effectiveness of specific physiotherapy approaches for low back pain management.

Posterior occipitocervical reconstruction using cervical pedicle screws and plate-rod systems

Abstract: Study design This retrospective study was conducted to analyze the clinical results in 26 patients with lesions at the craniocervical junction that had been treated by occipitocervical reconstruction using pedicle screws in the cervical spine and occipitocervical rod systems. Objectives To evaluate the effectiveness of pedicle screw fixation in occipitocervical reconstructive surgery and to introduce surgical techniques. Summary of background data Many methods of occipitocervical reconstruction have been reported, but there have been no reports of occipitocervical reconstruction using pedicle screws and occipitocervical rod systems for reduction and fixation. Methods Twenty-six patients with lesions at the craniocervical junction underwent reconstructive surgery using pedicle screws in the cervical spine and occipitocervical rod systems. The occipitocervical lesions were atlantoaxial subluxation associated with basilar invagination, which was caused by rheumatoid arthritis in 19 patients and other disorders in 7. The lowest cervical vertebra of fusion in 16 patients was C2, and the remaining 10 patients underwent fusion downward from C3 to C7. Flexion deformity of the occipitoatlantoaxial complex was corrected by application of extensional force, and upward migration of the odontoid process was reduced by application of combined force of extension and distraction between the occiput and the cervical pedicle screws. Results Solid fusion was achieved in all patients except two with metastatic vertebral tumors who did not receive bone graft for fusion. Correction of malalignment at the craniocervical junction was adequate, and postoperative magnetic resonance imaging showed improvement of anterior compression of the medulla oblongata. There were no neurovascular complications of cervical pedicle screws. Conclusions Occipitocervical reconstruction by the combination of cervical pedicle screws and occipitocervical rod systems provided the high fusion rate and sufficient correction of malalignment in the occipitoatlantoaxial region. Results of this study showed the effectiveness of cervical pedicle screw as a fixation anchor for occipitocervical reconstruction.

Compression-induced changes in intervertebral disc properties in a rat tail model.

Abstract: Study design An Ilizarov-type apparatus was applied to the tails of rats to assess the influence of immobilization, chronically applied compression, and sham intervention on intervertebral discs of mature rats. Objectives To test the hypothesis that chronically applied compressive forces and immobilization cause changes in the biomechanical behavior and biochemical composition of rat tail intervertebral discs. Summary of background data Mechanical factors are associated with degenerative disc disease and low back pain, yet there have been few controlled studies in which the effects of compressive forces on the structure and function of the disc have been isolated. Methods The tails of 16 Sprague-Dawley rats were instrumented with an Ilizarov-type apparatus. Animals were separated into sham, immobilization, and compression groups based on the mechanical conditions imposed. In vivo biomechanical measurements of disc thickness, angular laxity, and axial and angular compliance were made at 14-day intervals during the course of the 56-day experiment, after which discs were harvested for measurement of water, proteoglycan, and collagen contents. Results Application of pins and rings alone (sham group) resulted in relatively small changes of in vivo biomechanical behavior. Immobilization resulted in decreased disc thickness, axial compliance, and angular laxity. Chronically applied compression had effects similar to those of immobilization alone but induced those changes earlier and in larger magnitudes. Application of external compressive forces also caused an increase in proteoglycan content of the intervertebral discs. Conclusions The well-controlled loading environment applied to the discs in this model provides a means of isolating the influence of joint-loading conditions on the response of the intervertebral disc. Results indicate that chronically applied compressive forces, in the absence of any disease process, caused changes in mechanical properties and composition of tail discs. These changes have similarities and differences in comparison with human spinal disc degeneration.

Electromyographic responses of back and limb muscles associated with spinal manipulative therapy.

Abstract: Study design Ten young, asymptomatic male subjects underwent 11 clinically relevant spinal manipulative treatments along the length of the spine to test the magnitude and extent of reflex responses associated with the treatments. Objectives To determine the magnitude and extent of reflex responses elicited by spinal manipulative treatments. Summary of background data Spinal manipulative treatments have been associated with a reflexogenic relief of pain and a loss of hypertonicity in muscles within the treatment area. However, there is no study in which results show the probability of occurrence or the extent of reflex responses during spinal manipulative treatments. Methods Asymptomatic subjects received spinal manipulative treatments on the cervical, thoracic, and lumbar levels and on the sacroiliac joint. Reflex activities were measured using 16 pairs of bipolar surface electrodes placed on the back and proximal limb musculature. The percentage of occurrence and the extent of reflex responses in the back and proximal limb musculature were determined. Results Each treatment produced consistent reflex responses in a target-specific area. The reflex responses occurred within 50-200 msec after the onset of the treatment thrust and lasted for approximately 100-400 msec. The responses were probably of multireceptor origin and were elicited asynchronously. Conclusions This is the first study in which results show a consistent reflex response associated with spinal manipulative treatments. Because reflex pathways are evoked systematically during spinal manipulative treatment, there is a distinct possibility that these responses may cause some of the clinically observed beneficial effects, such as a reduction in pain and a decrease in hypertonicity of muscles.

Motion analysis of cervical vertebrae during whiplash loading.

Abstract: STUDY DESIGN: The motion of each cervical vertebra during simulated rear-end car collisions was analyzed. OBJECTIVES: To clarify the mechanism of zygapophysial joint injury during whiplash loading. SUMMARY OF BACKGROUND DATA: The zygapophysial joint is the suspected origin of neck pain after rear-end car collision. However, no studies have been conducted on the mechanisms of zygapophysial joint injuries. METHODS: Ten healthy male volunteers participated in this study. Subjects sat on a sled that glided backward on inclined rails and crashed into a damper at 4 km/kr. The motion of the cervical spine was recorded using cineradiography. Each vertebra's rotational angle and the instantaneous axes of rotation of the C5-C6 motion segments were quantified. These measurements implemented the template method. RESULTS: There were three distinct patterns of cervical spine motion after impact. In the flexion-extension group, C6 rotated backward before the upper vertebrae in the early phase; thus, the cervical spine showed a flexion position (initial flexion). After C6 reached its maximum rotational angle, C5 was induced to extend. As upper motion segments went into flexion, and the lower segments into extension, the cervical spine took an S-shaped position. In this position, the C5-C6 motion segments showed an open-book motion with an upward-shifted instantaneous axis of rotation. CONCLUSIONS: The cervical spine is forced to move from the lower vertebrae during rear-end collisions. This motion completely differs from normal extension motion and is probably related to the injury mechanism. Language: en

The efficacy of active rehabilitation in chronic low back pain. Effect on pain intensity, self-experienced disability, and lumbar fatigability.

Abstract: Study Design. A randomized study comparing the results of active rehabilitation and passive control treatment in patients with chronic low back pain with follow-up at 6 months and 1 year. Objectives. To study the efficacy of active rehabilitation on pain, self-experienced disability, and lumbar fatigability. of Background Data. Exercises in an outpatient setting are widely used for the treatment of chronic low back pain. The efficacy of the active rehabilitation approach has been documented in randomized control studies, but these studies have seldom been focused on lumbar fatigability, which is now recognized as a frequent problem among patients with chronic low back pain. Methods. Fifty-nine middle-aged patients (37 men and 22 women) with nonspecific chronic low back pain were randomly assigned to 12 weeks' active rehabilitation or to a passive control treatment (massage, thermal therapy). Pain and disability index, low back pain intensity (visual analog scale, 100 mmi, and the objectively assessed lumbar muscle fatigability (spectral electromyogram, mean power frequency slope [MPF SLOPE ]) in a new 90-second submaximal isoinertial back endurance test were recorded before and after the interventions and at 6-month and 1-year follow-up visits. Results. Results of repeated measures multivariate analysis of variance indicated that back pain intensity (visual analog scale) and functional disability (pain and disability index score) decreased, and lumbar endurance (MPF SLOPE ) improved significantly more (P < 0.05) in the active rehabilitation group than in the passive control treatment group, when measured at a 1-year follow-up examination. The group difference in visual analog scale and pain and disability index changes became even more significant at the end of 1 year. The change in lumbar endurance was significantly greater in the active rehabilitation group than in the passive control treatment group at the 6-month follow-up, but not at the 1-year follow-up. Conclusions. The active progressive treatment program was more successful in reducing pain and self-experienced disability and also in improving lumbar endurance than was the passive control treatment. However, the group difference in lumbar endurance tended to diminish at the 1-year follow-up.

Development of the Neck Pain and Disability Scale. Item analysis, face, and criterion-related validity.

Abstract: Study design The development and testing of a new comprehensive measure of neck pain and disability, the Neck Pain and Disability Scale. Objectives To provide an initial evaluation of the Neck Pain and Disability Scale's reliability and validity. Summary of background data Although several measures exist for generalized pain and disability, none is specific for neck pain. More specific measurements should improve assessment of treatments and clinical research aimed at cervical pain syndromes. Methods The Neck Pain and Disability Scale was designed using the Million Visual Analogue Scale as a template and consists of 20 items that assess neck pain. In this study, 100 patients with neck pain, 52 patients with lower back and leg pain, and 27 pain-free volunteers were rated by the Neck Pain and Disability Scale. In addition, a subset of the 47 patients with neck pain were rated by several other established psychometric instruments. Results An item analysis showed a high degree of internal consistency among the 20 items on the Neck Pain and Disability Scale (r = 0.93), and face validity was established by comparing patients who had neck pain as well as lower back and leg pain with a pain-free group. The Neck Pain and Disability Scale scores correlated with the Oswestry Disability Questionnaire, the Pain Disability Index, and psychological measures of depression and neuroticism. Conclusions The results suggest a highly reliable instrument for evaluating neck pain with at least four underlying dimensions. Further work to address the predictive validity of this new tool are under way.

Trunk muscle weakness as a risk factor for low back pain: A 5-year prospective study

Abstract: Study design A 5-year prospective study Objectives To investigate trunk muscle weakness as a risk factor for low back pain in asymptomatic volunteers Summary of background data Muscle strength has not been sufficiently studied as a risk factor for low back pain Methods The study participants included 30 male and 37 female volunteers (mean age, 17 +/- 2 years), who neither reported nor had ever been treated for low back pain Trunk muscle strength was measured isokinetically (60 degrees/sec), using the trunk extension and flexion and torso rotation units The peak torques of the volunteers' extension, flexion, rightward rotation, and leftward rotation were measured, and the agonist/antagonist ratios were calculated as extension/flexion and left rotation/right rotation ratio The volunteers then were followed prospectively for 5 years to determine the incidence of low back pain and were classified into a non-low back pain group (volunteers with no low back pain during the 5-year follow-up period) and a low back pain group (volunteers who experienced low back pain during this period) Results The low back pain group consisted of 8 male and 10 female volunteers There were no significant differences between the non-low back pain group and the low back pain group regarding age, height, weight, the peak torque values, or the left rotation/right rotation ratio However, the extension/flexion ratio of the low back pain group (men, 096 +/- 027; women, 077 +/- 019) demonstrated significantly lower values than that of the non-low back pain group (123 +/- 028 and 100 +/- 016 for men and women, respectively, P Conclusions An imbalance in trunk muscle strength, ie, lower extensor muscle strength than flexor muscle strength, might be one risk factor for low back pain

Seven- to 20-year outcome of lumbar discectomy.

Abstract: Study design A retrospective, follow-up study. Objectives To assess the effects of conventional surgery for lumbar disc herniation over an extended period of time and to examine factors that might correlate with unsatisfactory results. Summary of background data Although the short-term results of lumbar discectomy are excellent when there is a proper patient selection, the reported success rates in the long-term follow-up studies vary, and few factors have been implicated for an unsatisfactory outcome. Methods One hundred-nine patients with surgically documented herniated lumbar disc were analyzed, retrospectively, by an independent observer. Long-term follow-up (mean 12.2 years) was done by a mailed, self-report questionnaire that included items about pain relief in the back and leg, satisfaction with the results, need for analgesics, level of activity, working capacity, and reoperations. Subjective disability was measured by the Oswestry questionnaire. Radiographic review was carried out in 66% of patients. End results were assessed using the modified Stauffer-Coventry's evaluating criteria. Several variables were examined to assess their influence to the outcome. Results The late results were satisfactory in 64% of patients. The mean Oswestry disability score was 18.9. Of the 101 patients who had primary procedures, 28% still complained of significant back or leg pain. Sixty-five percent of patients were very satisfied with their results, 29% satisfied, and 6% dissatisfied. The reoperation rate was 7.3% (8 patients), about one-third of which was due to recurrent disc herniation. Sociodemographic factors predisposing to unsatisfactory outcome, including female gender, low vocational education, and jobs requiring significant physical strenuousness. Disc space narrowing was common at the level of discectomy, but was without prognostic significance. Conclusions The long-term results of standard lumbar discectomy are not very satisfying. More than one-third of the patients had unsatisfactory results and more than one quarter complained of significant residual pain. Heavy manual work, particularly agricultural work, and low educational level were negative predictors of a good outcome. These indicators should be used preoperatively to identify patients who are at high risk for an unfavorable long-term result.