Importance of the Intersegmental Trunk Muscles for the Stability of the Lumbar Spine: A Biomechanical Study In Vitro
Ulrich Quint, Hans-Joachim Wilke, Aboulfazl Shirazi-Adl, Mohamad Parnianpour, Franz Löer, and Lutz E. Claes

A study was conducted to assess quantitatively the role of synergistic and antagonist activity of muscles on the response of L4-L5 functional units subjected to well-controlled external moments of multisegmented L2-S2 passive spines. The simulated coactivation significantly stabilized L4-L5 during pure lateral bending and axial moments.

Effect of Age and Loading Rate on Human Cervical Spine Injury Threshold
Frank A. Pintar, N. Yoganandan, and Liming Voo

A statistical analysis of human cadaver cervical spine injury experiments was performed to determine the effects of age, gender, and loading rate on the force at failure. Age and loading rate are coupled in their effect. Male spines were 600 N stronger than female spines.

The Anatomic Location of the Dorsal Ramus of the Cervical Nerve and Its Relation to the Superior Articular Process of the Lateral Mass
Nabil A. Ebraheim, Steve T. Haman, Rongming Xu, and Richard A. Yeasting

The authors analyzed the anatomic relation of the dorsal ramus of the cervical spinal nerve to the lateral mass. It was found that the dorsal ramus of the cervical spinal nerve is closer to the anterolateral corner of the base of the superior articular process. Lateral mass screws directed to the anterolateral corner of the base of the superior articular process should be avoided.

Capacity of the Clinical Picture to Characterize Low Back Pain Relieved by Facet Joint Anesthesia: Proposed Criteria to Identify Patients With Painful Facet Joints
Michel Revel, Serge Poiraudeau, Guy Robert Auleley, Christine Payan, Afiwa Denke, Minh Nguyen, Alain Chevrot, and Jacques Fermanian

Eighty patients with low back pain were subjected to a randomized controlled study to evaluate facet joint injections of lidocaine versus saline and to assess clinical characteristics as predictors of a positive response. Lidocaine was significantly superior to placebo. Five clinical characteristics were identified that identify patients whose pain will be significantly relieved by facet joint anesthesia.

Interrater and Intrarater Reliability in the Measurement of Kyphosis in Postmenopausal Women With Osteoporosis
Kathleen M. A. Lundon, Audrey M. W. Y. Li, and Sonia Bibershtein

A study was performed to determine the most reliable, cost-effective, noninvasive, and clinically feasible method of measuring spinal kyphosis in postmenopausal women with osteoporosis. The DeBrunner's kyphometer and the flexicurve ruler were used for noninvasive measurement of thoracic kyphosis. The intrarater and interrater reliability of and between each method was compared with roentgenographic films obtained in the sagittal plane.

Increase in Sick Leave Rates Caused by Back Pain Among Pregnant Swedish Women After Amelioration of Social Benefits: A Paradox
Adam Sydsjö, Gunilla Sydsjö, and Barbro Wijma

According to the results of this study, the number of women granted sick leave because of back pain during pregnancy tripled between 1978 and 1986. The average number of days of sick leave attributable to back pain quadrupled in the youngest group and doubled in the two other age groups.

A Report From the Second International Forum for Primary Care Research on Low Back Pain: Reexamining Priorities
Jeffrey M. Borkan, Bart Koes, Shmuel Reis, and Daniel C. Cherkin

A group consensus process at the Second International Forum for Primary Care Research on Low Back Pain at The Hague, The Netherlands, in 1997 is described. A reexamination of the research agenda for low back pain in primary care is discussed in light of recent progress, and new directions for investigatory efforts are suggested.

Primary Care Research on Low Back Pain: The State of the Science
Daniel C. Cherkin

The past few years have witnessed an explosion of primary care-relevant research on low back pain. If research is to lead to substantial improvements in primary care for low back pain, however, the focus must be broadened to embrace an existing but neglected paradigm, the biopsychosocial model.

Outcome Measures for Low Back Pain Research: A Proposal for Standardized Use
Richard A. Deyo, Michele Battie, A. J. H. M. Beurskens, Claire Bombardier, Peter Croft, Bart Koes, Antti Malmivaara, Martin Roland, Michael Von Korff, and Gordon Waddell

Recommendations are made for a standardized battery of outcome instruments to be used in clinical trials and other types of outcomes research. The recommended instruments include measures of patient symptoms, function, general well-being, work disability, and satisfaction with care.

Methodologic Issues in Low Back Pain Research in Primary Care
Lex M. Bouter, Maurits W. van Tulder, and Bart W. Koes

Four important methodologic challenges in low back pain research in primary care are discussed, including study designs, definition of low back pain, quantification of determinants of low back pain and control for extraneous factors, and outcome assessment, especially the responsiveness of outcome measures. In years to come, low back pain researchers are challenged to overcome some of these (and other) problems to improve the quality of low back pain research in primary care.

Chronicity of Back Problems During Working Life
Harald S. Miedema, Astrid M. J. Chorus, Cees W. J. Wevers, and Sjef van der Linden

A 7-year follow-up study was conducted in patients who consulted with their general practitioners for an episode of back pain, to determine the proportion of chronic back problems, health outcomes, labor force participation, and determinants of chronicity.