Smoking: Low Back Injuries and the Course of Care

Smoking is directly associated with low back pain.¹ Several studies have confirmed the link between severe low back pain and smoking.^1,2,4,5 The risk for a patient experiencing low back trouble is increased when cigarettes enter into the picture. Daily smoking has been implicated as a factor which can increase the risk of low back trouble.^3,13

In a recent study of industrial low back injuries, the risk of a smoker reporting an industrial back injury was 1.4 times that of a non-smoker.⁵ The risk of suffering from an acute prolapsed lumbar disc is increased for smoking patients who have smoked in the past year.⁶ Another study by Deyo stated that the risk for smokers experiencing low back pain is greatest in young adults less than 45 years of age. The risk steadily increases with cumulative exposure and with the degree of maximum daily exposure.⁷

There have been several hypotheses proposed for the link between smoking and low back pain. Smoking is known to induce chronic coughing which elevates the intradiscal pressure and increases the risk of protrusion and prolapse for lumbar discs.^1,3,13 Nicotine has been demonstrated to decrease the vertebral body blood flow in animals. Since the disc receives its nutrition by way of diffusion through the vertebral body end-plates, smoking may adversely affect the metabolism of the lumbar disc and thereby increase its susceptibility to mechanical injury.^3,7 Smoking has also been linked to osteoporosis in the lumbar vertebral bodies. Trabecular microfractures may result due to the osteoporosis and create another cause for low back pain.^1,3,11

In a study of the failure rate of lumbar spinal fusion conducted by Brown, et al., smoking was viewed as a major risk factor for pseudoarthrosis.8 In Brown's study, the success rate for lumbar spinal fusion in a non-smoking population was 92 percent. The success rate for spinal fusion in a population of smoking patients dropped to 60 percent. Conversely, one could say that the failure rate of spinal fusion in non-smokers is only eight percent and the failure rate in smokers is 40 percent.

Thus, it appears that smoking leads to a failure rate five times greater than in non-smoking populations. It was noted that the Po2 level in smoking patients was 78.5 percent. The Po2 level for non-smoking patients was shown to be between 95 percent to greater than 97 percent. The oxygen saturation levels were shown to be much lower for smokers as well. Smokers demonstrated an O2 saturation level of 92.2 percent while non-smokers demonstrated levels in excess of 95 percent. Thus, the high pseudoarthrosis rates have been attributed to high carbon monoxide levels producing arterial constriction and inadequate oxygenation of the injured tissues.⁸

Additionally, smoking has been proposed as a marker for a complex combination of social traits associated with increased risk for low back injury. The habit is most prevalent in the lower socioeconomic groups, for whom job demands, life stress, income, and other health habits may increase the risk for low back pain.^9,10 Smoking has also been proposed as a marker for depression and anxiety, two of the major psychological factors faced in low back injuries.⁷ For the chiropractic physician, a smoking patient will most probably require a longer course of care than would the non-smoking patient.

In addition to the explanations cited, smokers are a less active group of patients and may demonstrate the tendency to become more sedentary following an injury which may further prolong the course of care. It is helpful to identify as many factors which may extend the normal course of care so that a reasonable prognosis may be rendered. Smoking has been identified as a risk factor for prolonged recovery from a spinal injury.¹⁴

References

1. Svensson H, et al: Low back pain in relation to other diseases and cardiovascular risk factors. Spine, 8(3):1983.

    

2. Frymoyer JW, et al: Risk factors in low back pain. JBJS, 65-A(2):1983.

    

3. Biering-Sorenson F, Thomsen C: Medical, social, and occupational history as risk factors for low back trouble in a general population. Spine, 11(7):1986.

    

4. Cox JM, Trier KK: Exercise and smoking habits in patients with and without low back and leg pain. JMPT, 10(5):1987.

    

5. Battie MC, Bigos S: Indusrial back pain complaints: A broader perspective. Ortho Clin North Am., 22(2):l991.

    

6. Kelsey JL, et al: Acute prolapsed lumbar intervertebral disc: An epidemiological study with special reference to driving automobiles and cigarette smoking. Spine, 9(6):1984.

    

7. Deyo RA, Bass JE: Lifestyle and low back pain: The influence of smoking and obesity. Spine, 14(5):1989.

    

8. Brown CW, Orme TJ, Richardson HD: The rate of pseudoarthrosis (surical non-union) in patients who are smokers and patients who are non-smokers: A comparison study. Spine.

    

9. Millard RW, Jones RH: Construct validity of practical questionnaires for assessing disability of low back pain. Spine, 16(7): 1991.

    

10. Hildebrandt J, et al: The use of pain drawing in the screening for psychological involvement in complaints of low back pain. Spine, 13(6):1988.

     

11. Hansson T and Roos B: Microcalluses of the trabeculae in lumbar vertebrae and their relation to bone mineral content. Spine, 6(5):1980.

     

12. Kahanovitz, N: Diagnosis and Treatment of Low Back Pain, Raven Press, New York, 1991.

     

13. Pope MH, Frymoyer JW, Andersson G: Occupational Low Back Pain, Praeger, New York, 1984.

     

14. Tufo HM, Rothwell MG, Frymoyer JW: Managing the quality of care for low back pain. The Adult Spine: Principles and Practice, Raven Press, New York, 1991.