Cypress BK.  Characteristics of physician visits for back symptoms: a national perspective. Am J Public Health . 1983;;73:389-395.
Deyo RA, Tsui-Wu JY.  Descriptive epidemiology of low-back pain and its related medical care in the United States. Spine . 1987;;12:264-268.
Deyo RA, Loeser JD, Bigos SF.  Herniated lumbar intervertebral disk. Ann Intern Med . 1990;;112: 598-603.
White AA, Gordon SL.  Synopsis: workshop on idiopathic low-back pain. Spine . 1982;;7:141-149.
Nachemson A.  The lumbar spine: an orthopedic challenge. Spine . 1976;;1:59-71.
Weisel SE, Tsourmas N, Feffer H, Citrin CM, Patronas N.  A study of computer-assisted tomography, I: the incidence of positive CAT scans in an asymptomatic group of patients. Spine . 1984;;9:549-551.
Boden SD, Davis DO, Dina TS, Patronas NJ, Wiesel SW.  Abnormal magnetic resonance scans of the lumbar spine in asymptomatic subjects. J Bone Joint Surg Am . 1990;;72:403-408.
Liang M, Komaroff AL.  Roentgenograms in primary care patients with acute low back pain: a cost-effectiveness analysis. Arch Intern Med . 1982;; 142:1108-1112.
Deyo RA.  Early diagnostic evaluation of low back pain. J Gen Intern Med . 1986;;1:328-338.
Deyo RA, Diehl AK.  Cancer as a cause of back pain: frequency, clinical presentation, and diagnostic strategies. J Gen Intern Med . 1988;;3:230-238.
Scavone JG, Latshaw RF, Weidner WA.  Anteroposterior and lateral radiographs: an adequate lumbar spine examination. Am J Radiol . 1981;;136: 715-717.
GehweilerJA, Daffner RH.  Low back pain: the controversy of radiologic evaluation. Am J Radiol . 1983;;140:109-112.
Brekkan A.  Radiographic examination of the lumbosacral spine: an 'age-stratified' study. Clin Radiol . 1983;;34:321-324.
Carter ET, McKenna CH, Brian DD, Kurland LT.  Epidemiology of ankylosingspondylitisin Rochester, Minnesota, 1935-1973. Arthritis Rheum . 1979;; 22:365-370.
Hawkins BR, Dawkins RL, Christiansen FT, Zilko PJ.  Use of the B27 test in the diagnosis of ankylosing spondylitis: a statistical evaluation. Arthritis Rheum . 1981;;24:743-746.
Waldvogel FA, Vasey H.  Osteomyelitis: the past decade. N Engl J Med . 1980;;303:360-370.
Sapico FL, Montgomerie JZ.  Pyogenic vertebral osteomyelitis: report of nine cases and review of the literature. Rev Infect Dis . 1979;;1:754-776.
Baker AS, Ojemann RG, Swartz MN, et al.  Spinal epidural abscess. N Engl J Med . 1975;;293: 463-468.
Chandrasekar PH.  Low back pain and intravenous drug abusers. Arch Intern Med . 1990;;150: 1125-1128.
McCombe PF, Fairbank JCT, Cockersole BC, Pynsent PB.  Reproducibility of physical signs in low-back pain. Spine . 1989;;14:908-918.
Bauer RL, Deyo RA.  Low risk of vertebral fracture in Mexican American women. Arch Intern Med . 1987;;147:1437-1439.
Calin A, Porta J, Fries JF, Schurman DJ.  Clinical history as a screening test for ankylosing spondylitis. JAMA . 1977;;237:2613-2614.
Gran JT.  An epidemiological survey of the signs and symptoms of ankylosing spondylitis. Clin Rheumatol . 1985;;4:161-169.
Van der Linden S, Valkenburg HA, Cats A.  Evaluation of diagnostic criteria for ankylosing spondylitis: a proposal for modification of the New York criteria. Arthritis Rheum . 1984;;27:361-368.
Calin A, Kaye B, Sternberg M, Antell B, Chan M.  The prevalence and nature of back pain in an industrial complex: questionnaire and radiographic and HLA analysis. Spine . 1980;;5:201-205.
Reynolds PMG.  Measurement of spinal mobility: a comparison of three methods. Rheumatol Rehabil . 1975;;14:180-185.
Rae PS, Waddell G, Venner RM.  A simple technique for measuring lumbar spinal flexion. JRColl Surg Edin . 1984;;29:281-284.
MollJMH, Wright V.  An objective clinical study of chest expansion. Ann Rheum Dis . 1972;;31:1-8.
Potter NA, Rothstein JM.  Intertester reliability for selected clinical tests of the sacroiliac joint. Phys Ther . 1985;;65:1671-1675.
Russell AS, Maksymowych W, LeClercq S.  Clinical examination of sacroiliac joints: a prospective study. Arthritis Rheum . 1981;;24:1575-1577.
Blower PW, Griffin AJ.  Clinical sacroiliac tests in ankylosing spondylitis and other causes of low back pain. Ann Rheum Dis . 1984;;43:192-195.
Mayer TG, Tencer AF, Kristoferson S, Mooney V.  Use of non invasive techniques for quantification of spinal range of motion in normal subjects and chronic low-back pain dysfunction patients. Spine . 1984;;9:588-595.
Spangfort EV.  Lumbar disc herniation: a computer aided analysis of 2504 operations. Acta Orthop Scand . 1972;;(
(suppl 142)
):1-93.
Alpers BJ.  The neurological aspects of sciatica. Med Clin North Am . 1953;;37:503-510.
Brieg A, Troup JDG.  Biomechanical considerations in the straight-leg-raising test: cadaveric and clinical studies of medial hip rotation. Spine . 1979;; 4:242-250.
CharnleyJ.  Orthopedic signs in the diagnosis of disc protusion with special reference to the straight leg raising test. Lancet . 1951;;1:186-192.
Kosteljanetz M, Bang F, Schmidt-Olsen S.  The clinical significance of straight-leg-raising (Lasegue's sign) in the diagnosis of prolapsed lumbar disc. Spine . 1988;;13:393-395.
Waddell G, Main CS, Morris EW, et al.  Normality and reliability in the clinical assessment of backache. BMJ . 1982;;284:1519-1523.
Hoehler FK, Tobis JS.  Low back pain and its treatment by spinal manipulation: measures of flexibility and asymmetry. Rheumatol Rehabil . 1982;; 21:21-26.
Hsieh CY, Walker JM, Gillis K.  Straight leg raising test: comparison of three instruments. Phys Ther . 1983;;63:1429-1432.
Kosteljanetz M, Espersen JO, Halaburt H, Miletic T.  Predictive value of clinical and surgical findings in patients with lumbago-sciatica: a prospective study (part 1). Acta Neurochir . 1984;;73: 67-76.
Hakelius A, Hindmarsh J.  The comparative reliability of preoperative diagnostic methods in lumbar disc surgery. Acta Orthop Scand . 1972;;43:234-238.
Hakelius A, Hindmarsh J.  The significance of neurological signs and myelographic findings in the diagnosis of lumbar root compression. Acta Orthop Scand . 1972;;43:239-246.
Hudgins RW.  The crossed straight leg raising test: a diagnostic sign of herniated disc. J Occup Med . 1979;;21:407-408.
Shiqing X, Quanzhi Z, Dehao F.  Significance of straight-leg-raising test in the diagnosis and clinical evaluation of lower lumbar intervertebral disc protrusion. JBone Joint Surg Am . 1987;;69:517-522.
Kortelainen P, Puranen J, Koivisto E, Lahde S.  Symptoms and signs of sciatica and their relation to the localization of the lumbar disc herniation. Spine . 1985;;10:88-92.
Blower PW.  Neurologic patterns in unilateral sciatica. Spine . 1981;;6:175-179.
Schwartz RS, Morris JGL, Crimmins D, et al.  A comparison of two methods of eliciting the ankle jerk. Aust N Z J Med . 1990;;20:116-119.
Keegan JJ.  Dermatome hypalgesia associated with herniation of intervertebral disk. Arch Neurol Psychiatry . 1943;;50:67-83.
Aronson HA, Dunsmore RH.  Herniated upper lumbar discs. J Bone Joint Surg Am . 1963;;45:311317.
Morris EW, DiPaola M, Vallance R, Waddell G.  Diagnosis and decision making in lumbar disc prolapse and nerve entrapment. Spine . 1986;;11:436-439.
Turner JA, Ersek M, Herron L, Deyo R.  Surgery for lumbar spinal stenosis: attempted metaanalysis of the literature. Spine . 1992;;17:1-8.
Hawkes CH, Roberts GM.  Neurogenic and vascular claudication. J Neurol Sci . 1978;;38:337-345.
Kostuik JP, Harrington I, Alexander D, Rand W, Evans D.  Cauda equina syndrome and lumbar disc herniation. J Bone Joint Surg Am . 1986;;68: 386-391.
O'Laoire SA, Crockard HA, Thomas DG.  Prognosis for sphincter recovery after operation for cauda equina compression owing to lumbar disc prolapse. BMJ . 1981;;282:1852-1854.
Tay ECK, Chacha PB.  Midline prolapse of a lumbar intervertebral disc with compression of the cauda equina. J Bone Joint Surg Br . 1979;;61:43-46.
Spitzer WO, LeBlanc FE, Dupuis M, et al.  Scientific approach to the assessment and management of activity-related spinal disorders: a monograph for clinicians: report of the Quebec Task Force on Spinal Disorders. Spine . 1987;;12(
(suppl 7)
):S16S21.
Deyo RA, Bigos SJ, Maravilla KR.  Diagnostic imaging procedures for the lumbar spine. Ann Intern Med . 1989;;111:865-867.
Walsh NE, Dumitru D.  The influence of compensation on recovery from low back pain. Occup Med . 1988;;3:109-121.
Gatchel RJ, Mayer TG, Capra P, Diamond P, Barnett J.  Quantification of lumbar function, VI: the use of psychological measures in guiding physical functional restoration. Spine . 1986;;11:36-42.
Korbon GA, DeGood DE, Schroeder ME, Schwartz DP, Shutty MS.  The development of a somatic amplification rating scale for low-back pain. Spine . 1987;;12:787-791.
Burnam AM, Wells KB, Leake B, Landsverk J.  Development of a brief screening instrument for detecting depressive disorders. Med Care . 1988;;26: 775-789.
Rucker L, Frye EB, Cygan RW.  Feasibility and usefulness of depression screening in medical outpatients. Arch Intern Med . 1986;;146:729-731.
Waddell G, McCullochJA, Kummel E, Vernner RM.  Nonorganic physical signs in low back pain. Spine . 1980;;5:117-125.