Musculo-Skeletal Medicine is an improvement, ... musculoskeletal medicine with doctors trained in .... University College London Medical School,. London WI. GEORGE DAVEY SMITH. Department of Public Health,. University of Glasgow,.
dysfunctional back pain, but it is not necessarily so when there is nerve root irritation. Rest should continue until activity ceases to cause persisting exacerbation of leg pain. The illustration of the "ergonomic position at a desk" contains some basic errors. The lumbar roll is positioned at the thoracolumbar junction and the low back is not supported at all over the iliac crests. The seat of the chair is higher at the front than at the back and would cause discomfort behind the knees. Much better would be a reverse slope or a wedge and the facility to alter the height of the seat to correspond with leg length. The desk itself is too high and the subject would have to lift his arms to reach over the sharp edge of the table and doing so would cause sustained tension in the shoulder muscles. Also, this easel would be impractical for day to day use, certainly for writing. Much more satisfactory is a 4 inch block placed under the back edge of a board which gives a slope similar to that seen in old desks. Such a system can be dismantled instantly when a flat surface is required. Back pain and indeed most musculoskeletal dysfunction is exceedingly common, but with a few notable exceptions it is poorly taught and poorly catered for within the present organisation of medical services. It is neither a rheumatic problem nor a surgical one, yet its study and proper management rely on the personal interest of individual rheumatologists and orthopaedic surgeons. The recently introduced Diploma in Musculo-Skeletal Medicine is an improvement, but we will never really get to grips with these problems until we bring everything together and establish a properly constituted specialty in musculoskeletal medicine with doctors trained in all aspects of musculoskeletal dysfunction and its appropriate management.
nerve root, thus making them all apparently suitable candidates for decompressive surgery, only 23 came to surgery. When reviewed at one year 142 had recovered satisfactorily. The cornerstone of treatment was serial epidural administration of steroid and local anaesthetic caudally on an outpatient basis. Lumbar epidural injection or periradicular infiltration at the appropriate level, confirmed under image intensifier, was the next step before surgical decompression was considered. An average of three injections (range 0-8) was received by each patient. Furthermore, when patients were rescanned at one year three quarters of the large intervertebral disc herniations had partly or completely resolved.6 The fact that patients suffering from sciatica can recover with aggressive conservative management and that this is often accompanied by resolution of the disc herniation has now been confirmed by researchers in the United States, Italy, and France. Serial epidural corticosteroid injections have a place in controlling inflammation, and thus pain. while nature takes its course. KEITH BUSH
Causal link not proved
I Frank A. Low back pain. BMJ 1993;306:901-9. (3 April.) 2 Bush K, Hillier S. A controlled study of caudal epidural injections oftriamcinolone plus procaine in the management of intractable sciatica. Spine 1991;16:572-5. 3 Dilke TPW, Burry HC, Grahame R. Extradural corticosteroid injection in the management of lumbar nerve root compression.
EDITOR,-M P M Burger and colleagues found an association between cigarette smoking and the presence of oncogenic human papillomavirus in the cervix of women with a reported cytological abnormality, which remained after adjustment for measures of sexual activity.' This provides the likely reason for the much observed association between cigarette smoking and risk of cervical cancer.2 If cigarette smoking status, for whatever reason, provides information on the likelihood of the presence of oncogenic human papillomavirus in the cervix over and above that provided by knowledge of the lifetime number of sexual partners and age at first intercourse then, given the likely causal role of oncogenic human papillomavirus in cervical cancer, it is not surprising that an association between cigarette smoking and risk of cervical cancer is found even after adjustment for these measures of sexual activity. Burger and colleagues consider that cigarette smoking and the presence of oncogenic human papillomavirus have a direct causal relation, possibly mediated by a local immunological defect in the cervix induced by smoking. We suggest that the explanation is probably more simple: the cigarette smoking status provides information about the probability of acquiring oncogenic human papillomavirus infection additional to that provided by crude measures of sexual activity such as the lifetime number of sexual partners and age at first intercourse.3'4 A recent study of heterosexually transmitted HIV infection in Haiti,5 for example, found that women who smoked had a relative odds for HIV infection of 3-4 after adjustment for the lifetime number of sexual partners. The adjusted relative odds for having had three or more lifetime sexual partners was also 3-4. However, the largest adjusted relative odds in the study-8-7-was for "having a dirt floor in the home." We think it improbable that dirt on the floor has a direct causal effect on the risk of being infected with HIV, and this illustrates, as does Burger and colleagues' study, that crude measures of sexual activity do not give complete information on the likelihood or degree of exposure to sexually transmitted agents. When other risk factors, such as cigarette smoking, are found to be associated with the presence of sexually transmitted diseases "independently" of these crude measures of sexual activity caution should be exercised before con-
BMJ 1973;ii:635-7.
4 Ridley MG, Kingsley GH, Gibson T, Grahame R. Out-patient lumbar epidural corticosteroid injection in the management of
sciatica. BrJ Rheumatol 1988;27:295-9. 5 Hitselberger WE, Witten RM. Abnormal myelograms in asymptomatic patients. J Neurosurg 1%8;28:204-6. 6 Bush K, Cowan N, Katz DE, Gishen P. The natural history of sciatica associated with disc pathology. A prospective study with clinical and independent radiological follow up. Spine 1992;17: 1205-12.
M PICKIN
Smoking linked to back pain
Serial epidural injections effective EDrrOR,-LOW back pain is a vast, controversial, and emotive subject. Andrew Frank invites criticism and does the populace suffering from back disorders a disservice, firstly, by dismissing epidural injections and, secondly, by suggesting that compromise of a nerve root requires surgical intervention with almost invariable success. Though I agree that a few apparently well controlled studies question the efficacy of epidural injection, these are open to practical criticism and are completely overshadowed by the vast number of studies in favour. In particular, the efficacy of epidural local anaesthetic and corticosteroid in the management of sciatica due to compromise of lumbosacral nerve roots has been shown with prospective randomised double blind studies.24 While predominantly managing spinal disorders over the past 15 years, I have found the facility to perform epidural injections essential and have done so on about 7000 occasions. It is tempting to think that sciatica due to compromise of nerve roots is best managed by some form of decompressive surgery, especially in this. age of easy access to computed tomography and magnetic resonance imaging, which show the shadows on which to operate. In about one third of the pain free population, however, radiculography, computed tomography, or magnetic resonance imaging would show an abnormality and it is naive to think that surgery is 95% successful. The literature is more in favour of an 80% success rate in relieving leg pain and a 60% success rate for back
EDITOR,-The recent review of low back pain (by AF) made little reference to the strong evidence linking smoking to the epidemic of back pain.' Smoking is associated with prolapsed lumbar intervertebral disc,2 3 as well as the first attack4 and the severity' of low back pain. A dose-effect relation has been documented between the severity of back pain and both the number of cigarettes smoked and the duration of smoking.5 Smoking is also associated with prolapsed cervical intervertebral disc (confirmed at operation6) and time off work due to neck and upper extremity symptoms.7 Potential explanations for this association include impaired blood supply to the particular spinal segment,2" carbon monoxidaemia,7 coughing," and ergonomic factors related to smoking, which may be related to people's attitudes, lifestyles, and behaviour patterns.2 57 The public knows that smoking increases the risks of arterial disease and cancer, but the perception that these diseases are unlikely to manifest for many years may reduce the incentive to stop smoking. Knowledge of the association between smoking and back pain, however, may provide an additional incentive, especially among younger people, as back problems may affect them sooner, threatening their earning potential and their ability to live full and active lives. The government's attitude to smoking may be influenced by its effects on the exchequer, which contributes to the costs of sickness absence related to low back pain (52-6 million certified working days in 1988-9-the largest single cause) and to lost output related to low back pain (estimated to be over £2000m in 1987-8). ANDREW FRANK JOY TOWNSEND
pain. In a series of 165 consecutive patients who presented with classic sciatica and computed tomographic confirmation of compromise of a
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Smoking and human papillomavirus infection
London WIN lAA
Haxby, York Y03 3EU 1 Frank A. Low back pain. BMJ 1993;306:901-9. (3 April.)
1 Frank AO. Low back pain. BMJ 1993;306:901-9. (3 April.) 2 Battie MC, Videman T, Gill K, Moneta GB, Nyman R, Kapario J, et al. Volvo award in clinical sciences. Smoking and lumbar intervertebral disc degeneration. An MRI study of identical twins. Spine 1991;16:1015-21. 3 Kelsey JL, Gittens PB, White AA III, Holford TR, Walter SD, O'Connor T, et al. Acute prolapsed lumbar intervertebral disc. An epidemiological study with special reference to driving automobiles and cigarette smoking. Spine 1984;9:608-13. 4 Biering-Sorensen F, Thomsen CE, Hilden J. Risk indicators for low back trouble. ScandJ Rehabil Med 1989;21:151-7. 5 FrymoyerJW, PopeMH, ClementsJH, Wilder DG, MacPherson B, Ashikaga T. Risk factors in low back pain. J BoneJoint Surg [Am] 1983;65:213-8. 6 Kelsey JL, Gittens PB, Walter SD, Southwick WO, Weil V, Holford TR, et al. An epidemiological study of acute cervical prolapsed intervertebral disc. J BoneJoint Surg [Am] 1984;66: 907-14. 7 Dimberg L, Olafson A, Stefansson E, Aagaard H, Oden A, Andersson GB, et al. Sickness absenteeism in an engineering industry-an analysis with special reference to absence for neck and upper extremity symptoms. Scand J Soc Med 1989;17:77-84.
Northwick Park Hospital,
Harrow, Middlesex HAI 3UJ
cluding causality. ANDREW N PHILLIPS Academic Department of Genitourinary Medicine, University College London Medical School, London WI GEORGE DAVEY SMITH Department of Public Health, University of Glasgow, Glasgow G12
BMJ VOLUME 306
8mAy1993
