Back to Physician Literature

.Contemporary Concepts in Spine Care
Radiographic Assessment for Patients With Low Back Pain
Edward D. Simmons, MD, BSc, CM, MSc, rACS, FRCS,* Richard D. Guyer, MD,t Arnold Graham-Smith, MD, FRCS, FACSJ and Richard Herzog, MIDS

Guidelines for radiographs of the lumbar spine are established. In general, radiographs are not believed to be necessary for a first episode of low back pain present for less than 7 weeks. Exceptions to this include various medical or physical findings, which are listed. In general, anteroposterior and lateral views only should be done initially. Indications for other views are discussed.
[Key words: low back pain, lumbar, radiography] Spine 1995;20:1839-1841

Although 80% of North Americans may experience low back pain, most episodes are of short duration and do not recur. Acute back pain resolves frequently within 7 weeks of onset. History and physical examinations are the mainstays in evaluations. Radiographic examinations of the lumbar spine may be wise in some, although not all cases. This statement provides guidelines for when evaluation by conventional radiography is and is not indicated for the evaluation of low back pain.

Historical Review
Radiography became available for evaluation of musculoskeletal problems early in the twentieth century. The ability to discern abnormalities that had only been presumed or found at autopsy led to widespread use of radiography to evaluate patients with back pain. Reliance on radiographs predated understandings of lumbar pathology and related clinical presentations that have been gained from research, surgical observations, and imaging techniques of more recent vintage.

Radiography became so important to patients and physicians that little criticism of its value has been published. Availability of good equipment for taking and processing x-ray film has made evaluations quick, convenient, and relatively inexpensive. Although avoidance of unnecessary radiation is an accepted general health dictum, exposure for one to five views of the lumbar spine with modem equipment has been considered safe except for pregnant women. The disadvantage of exposure to radiation and the expense of the taking and interpreting films must be weighed against potential benefits.

Rationale
Exposure of film by irradiation is relatively impeded by passage of the rays through body tissues. Dense, mineral-containing tissues, such as bone, impede more x-ray passage than soft tissues.

Radiographic examinations allow physicians to judge the configuration and alignment of bones in the lumbar spine with high degrees of accuracy, which rules in or but the presence of such problems as malalignment or changes in shape of the vertebrae from tumor, fracture, or infection. Undisplaced fractures and stress fractures that do not change the shape of bone may usually, although not always, be revealed by radiographs.

The configuration of spaces occupied by soft tissues, such as intervertebral disc and joint cartilage, may be appreciated even though the quality and shape of the soft tissues themselves are not well portrayed by the radiograph.

The alignment of vertebrae may be determined by the posture adopted by the patient, so that films taken under bending or weight-bearing stresses may reveal abnormal responses and allow the physician to determine the presence or absence of hypermobility or malalignment that was not discoverable by radiographs taken in a single posture.

Characteristic radiographic changes of such causes of back pain as fracture, osteomyelitis, and tumor may lead to important changes in the prescription the physician will give for future testing and treatment. The presence or absence of hypertrophic changes in posterior elements, spondylolysis, spondylolisthesis, or hypermobility may influence the prescription for a specific exercise regimen, modification of posture, or limitation of activity early in the course of the treatment of back pain.

Certain additional observations of relevance, such as presence of urolithiasis, cholelithiasis, or aortic aneurysm, may sometimes be gained from the study of lumbar radiographs made because of low back pain.

Results
In 1981, Scavone et al³ published a retrospective review of over 1000 lumbar spine radiographic examinations in 871 patients. They wanted to compare what had been discovered from the patients' history and physical examinations with what was learned from the radiographs. The results of almost half of the radiographs were normal, and an additional 30% yielded information of questionable clinical significance. Seventy-five percent of the radiographic examinations yielded no useful information. Many of these were studies carried out in the emergency room, and medicolegal considerations may have increased the use of radiographic studies. In patients with a history of minor trauma, no fractures were seen except in elderly women, therefore such films are not indicated in young and middle-aged persons who are otherwise healthy. Three hundred seventy-five follow-up examinations showed no radiologic interval changes, suggesting that the value of such studies, unless there has been change of symptoms, is questionable.

Also in 1981, Scavone et a¹⁴ published a review of the diagnostic value of different radiographic views of the lumbar spine. In 782 patients, only 2.4% had uniquely diagnostic findings on spot lateral and oblique spine films. It was recommended that these views should be eliminated from routine lumbar spine series. Clearly, in the at-risk population from spondylolysis, as determined by history, these studies are still useful.

In 1982, Liang and Komaroff² published a comparison of the benefits and costs of taking radiographs of everybody with backache on the initial visit compared with taking radiographs only if the patient's pain does not improve within an 8-week period. Patients with a previous history of tumor, back surgery, or possible infection were excluded from this study, as were patients with histories of sciatica or examinations suggesting neurologic deficit or abdominal disease. It was concluded that, in general, risks and costs of taking radiographs of everybody on the first visit do not seem to justify the small associated benefit.

In 1990, Costa et al¹ studied the variability of interpretation of plain lumbar spine radiographs in patients with low back pain and concluded that there was wide variability of interpretation by different physicians within the same specialty. Physicians disagreed in the interpretation of minor changes on radiographs, calling in question the routine use of plain radiographs in simple cases of low back pain.

Discussion
The review of these four papers illustrates the trend in the medical literature, which suggests that fewer radiographs should be taken and that not much more can be learned by taking multiple views than is already apparent on a simple front- and side-radiographs (anteroposterior and lateral views). A number of other articles reiterate these conclusions and have not been reviewed because they simply restate these conclusions.

Future Study
Prospective studies that document the values, for the patient and physician, of radiographs done for patients selected by a rational protocol would be of value to provide cost-benefit analyses and for critique of specific items in the protocol. For humanistic reasons, sham studies and denial of radiographic evaluation for those clearly in need should not be done. Analysis of the economic, social, and psychologic impacts of taking radiographs during the very early stages of back pain in certain carefully defined patients could be done by ranomized, controlled, prospective, independently evaluated methods.

Current Recommendations
For the patient with a first episode of low back pain, present for less than 7 weeks, who has not been treated or who is improving with treatment, no radiographs of the lumbar spine are indicated unless one or more of the following exceptions are obtained:

Atypical history including:
• Age over 65;
• History suggesting high risk for osteoporosis;
• Symptoms of urinary tract dysfunction;
• Symptoms of persisting sensory deficit;
• Pain worsening despite adequate treatment;
• Intense pain at rest;
• Pain worse at night;
• Fever, chills;
• Unexplained weight loss;
• History of injury of sufficient violence to cause
fracture;
• History of repetitive stress of sufficient severity to
cause stress fracture;
• Recurrent back pain with no radiographs in the
past 2 years;
• Previous lumbar surgery or fracture;
• History of radiographic abnormality elsewhere reported to patient but with no films or reliable report reasonably available;
• History of finding from other study (e.g., bone scan
or gastrointestinal series) that requires spine radiograph for correlation;
• Anticipation of need for another study or treatment that would be facilitated by preliminary radiograph (e.g., epidural injection);
• Patient unable to give a reliable history.

Atypical physical findings including:
• Significant motor deficit;
• Unexplained deformity.

Special psychologic or social circumstances including:
• Crippling cancerphobia focused on back pain;
• Inability to secure another evaluation within 7 weeks from the onset of pain;
• Need for immediate decision about career or athletic future;
• High risk for violent injury;
• Need for legal evaluation.

The above list of circumstances when taking radiographs of a patient with low back pain present for less than 7 weeks should serve as a guideline to which clinical judgment must be applied and is not to be construed as a list of circumstances in which radiography is necessarily indicated.

For the patient with recurrent low back pain, radiographs are not indicated if radiographic study has been done within 2 years, unless one of the above conditions is present as a change from previous circumstances, and the physician believes repeat study is clinically warranted. Patients with a history of a brief, self-limited previous episode of low back pain do not require radiography within the first 7 weeks of the current episode if they are improving and none of the above circumstances apply. Patients who have had a substantial previous episode or multiple episodes may require radiographs before 7 weeks.

What views of the lumbar spine should be taken? In general, anteroposterior and lateral views only should be done initially. In patients with multiple recurrences, chronic pain, or other historical or physical findings that suggest stenosis or instability, flexion- extension or standing lateral films may be part of an initial evaluation. Flexion-extension or standing lateral or right and left bending films may be needed in patients who have been found to have deformity by previous radiographs, 'who have history of lumbar surgery, or who are being evaluated for pseudoarthrosis. Oblique views may be indicated in patients whose history or physical findings suggest spondylolysis, stress fracture, or pseudoarthrosis if anteroposterior and lateral films have not adequately shown the lesion.

Who should perform radiographic evaluation of the lumbar spine? Physicians whose training and experience qualify them as expert in the interpretation of lumbar radiographs may describe the findings of such studies. This may include radiologists and physicians who are trained in the care of low back pain patients. Clinical correlation of radiographic findings should be done by the physician who provides the care, either from his/her review of the radiographs or from review of the description by a radiologist, or both. Technical performance of the study should be by a qualified radiographic technologist using approved equipment.

Each Contemporary Concepts review expresses a consensus representing general views of current practice and should not be used to dictate care of patients to the exclusion of innovation or tailoring to special circumstances.

References
1. Costa J, Paolaggi JB, Spira A. Reliability of interpretation of plain lumbar spine radiographs in benign mechanical low back pain. Spine 1991;16:426-8.
2. Liang M, Komaroff AL. Roentgenograms in primary care patients with acute low back pain: A cost-effective analysis. Arch Intern Med 1982;142:1108-12.
3. Scavone JC, Latshaw RF, Rohrar GV. Use of lumbar spine films: Statistical evaluation at a university teaching hospital. JAMA 1981;246:1105-8.
4. Scavone JG, Latshaw RF, Widener WA. Anteroposterior land lateral radiographs: An adequate lumbar spine examination. AJR Am J Roentgenol 199 1; 13 6:715-7.

Address reprint requests to
Edward D. Simmons, Jr., MD, BSc, CM, MSc, FACS, FRCS Department of Orthopaedic Surgery State University of New York at Buffalo
23S North Street Buffalo, NY 14201