CLAUDICATION OF CAUUA E Q U I N A
MACLEISH
CLAUDICATION OF THE CAUDA EQUINA D. G. MACLEISH Royal Melbourne Hospital The term “claudication o f the cauda equina” is examined. It has arisen from semantic errors, and a belief in ischamia f o r which there is no scientific evidence. fts use tends t o hamper rather than assist the investigation o f patients with obscure pain in the lower limb. A preferable alternative term, “atypical sciatica”, is suggested.
“To M Y GREAT SATISFACTION, the term took : and when The Spectator had stood godfather to it, any suspicion in the minds of respectable people that a knowledge of its parentage might have awakened was, of course, completely lulled.” With this quotation from Thomas Henry Huxley, the late E. S . J. King (1949) began his notable paper: The Lateral LymphoEpithelial Cyst Of The Neck (“branchial” cyst). H e pointed out that the term “branchial cyst” previously used for this structure was grossly misleading, represented an atiological error, and should be discarded. The neatness of a title, or its attractive alliteration, often gives it a prominence which it does not deserve, and disguises the confusion which may result from its adoption. This comniunication examines the term “claudication of the cauda equina” with regard to the justification for its use, and the practical implications resulting therefrom. Although derived from the Latin claudicare -to limp, the term “claudication” as now used implies ischzniia. Limping is an insignificant feature of patients described as having claudication, and claudication is not used to describe patients in whom a limp is prominent, hut not of ischzmic origin. The term “intermittent claudication of the spinal cord” was introduced by Dejerine ( I ~ I I ) ,who helieved that in the three cases he reported. exercise produced symptoms on the hasis of spinal cord ischzinia. Blau and Address for reprints : 96 Grattan Street, Carlton, Victoria 305.3.
62
Logue (1961), taking the cue from Dejerine, introduced the term “intermittent claudication of the cauda equina” to describe six patients who showed certain atypical features in a series of 300 consecutive cases of lumbar disc protrusion. Claudication of the spinal cord is said to be exceedingly rare, and the term has not caught on. On the other hand, claudication of the cauda equina seems to be flourishing, though why ischzmia of the cord should be less common than ischzmia of the cauda equina is hard to explain. ANATOMY A N D PHYSIOLOGY The blood supply of the cauda equina has not been measured, let alone any alterations of this produced by disease states. In the mouse, it has been found that exercising a single hind limb produces local increased vascularity in the corresponding segment of the spinal cord (Blau and Rushworth, 1958). In the rat, it has been observed that the rate of oxygen uptake by peripheral nerves is increased when the nerves are conducting impulses, and that the levels have parallelled the frequency of stimulation (Cranefield rt a&, 1957). The rate of oxygen uptake in excised sympathetic ganglia has been shown to rise during repeated stimulation (Larrabee, 1958). Little else is known about the effect of activity on the blood supply of the cauda equina. Considerable credence has been given to a conclusion that claudication time varies directly with oxygen tension (Evans, 1964). This conclusion has been quoted in several papers to indicate a relationship between “decreased AUST.N.Z.
1. SURG.,VOL.47-No.
I,
FEBRUARY, 1977
CLAUDICATION O F CAUDA EQUINA
blood oxygen level and increased pain” (Snyder et a& 1975). Evans did not measure blood oxygen levels. While a senior house officer at Oxford, he carried out an experiment on one patient who was subsequently shown to have adhesive arachnoiditis of the cauda equina. This patient was submitted to a fixed rate of work on a foot ergometer and allowed to breathe gases of varying oxygen tension, and reported when pain appeared in the exercised limb. Evans describes technical difficulty with part of the experiment, and his results are not statistically valid. , The anatomy of the lumbar spine, and the effects of posture, weight-hearing and walking on that region, are well known, yet seem to be overlooked by advocates of the term “claudication of the cauda equina”.
THE SYNDROME In 300 consecutive cases of lumbar disc protrusion, Blau and Logue (1961)found six patients in whom the pain and parzsthesia in the legs appeared related quantitatively to exercise. The pain in these patients was found to be in the lower back, huttock, thigh, lower leg, and sometimes the perineum. Although there was a relationship to exercise, there was also a relationship to prolonged standing. This latter has been somewhat glossed over. However. in their “typical case” it was a feature. Four months after operation, one such patient wrote : “I now enjoy walking and standing after manv years of walking and standitiq only when 1 could not avoid it . . . .” Frequently the protein content of the cerebrospinal fluid was raised. Five of the six patients were operated on, and in all an anterior disc protrusion with severe localized arachnoiditis was found Decompression, with or without removal of the protruded disc. resulted in complete relief of the intermittent symptoms. Rlau atid Logue postulated that when a person walks, there is an increased flow in the hlood vessels of the cauda equina. I n patients i n whom the volume of the spinal canal is reduced. thev believe that wch dilatation cqiiinot take place. so that a relative ischzmic neuritis occurs. Such an explanation overlooks the frequent situation where standinq alone induces the pain, and the frequent cases of compression AUST. N.Z. J.
SURG., VOL.
47-NO.
I,
FERRUARY, 1977
MACLEISH
(49 out of 50) where the symptoms are not related intermittently to walking. From the literature, one finds that where laminectomy has relieved the symptoms, the findings have been a narrow spinal canal, large disc protrusions either central or lateral, or spondylosis with enlarged facet joints and thickened ligamenta flava.
THEPROBLEM I t may be argued that since there is still a lot to learn about this condition, the name used is of little importance. However, the stimulus to submit this communication arose from an experience of now some 40 patients referred to a vascular surgery clinic in the belief that they were suffering from claudication of the cauda equina. Clearly the referring doctor believed in an ischzmic element, and often hoped that some vascular investigation or treatment might offer some relief. The first problem is one of differential diagnosis. The symptoms of the patients referred have eventually all been explained on the basis of spondylitis, disc Drotrusion, aortoiliac occlusive disease, or metastasis from carcinoma of the prostate. The problems of some of these patients have taken time to unravel, and some have had unproductive laminectomies. The concept of relative or absolute ischEmia of the cauda equina has retarded rather than accelerated the diagnostic processes. The second problem is that patients who clearly have significant aorto-iliac occlusive disease are often submitted to myelography. This has at times been unnecessary, and has on occasion made interpretation of subsequent arteriograms quite difficult. The third problem is that some patients with sciatica, albeit atypical, hut with perfectly normal leg pulses, have been submitted to aortopranhy i n the belief that this would yield some information regarding the blood supply of the cauda equina. This, of course, it cannot do.
CONCLUSIONS A scrutinv of the information from which the term “claudication of the cauda equina” has arisen makes it clear that many assumptions have been made. and some of these appear unwarranted. In Dractice, the vse of this term leads to a certain amount of confusion. To
63
WONG ET ALII
PERIPHERAL ARTERIAL DlSEASE I N HONG KONG
describe the syndrome in this way probably comes closer to the tail of the horse than is realized or was intended. It Seems Dreferable to use the term “atypical sciatica”. This term matches the present state of information about the condition, and does not prejudge further investigation into why certain positions of the lumbar spine, during standing or walking, cause more interference with the cauda equina than do others.
REFERE i i -c ES BLAU,J. N. and LOGUE,V. (1961),Lancet, I : 1081. BLAU, J. N. and RUSHWORTH, G. (1958), Brain, CRANEFIELD, 81: 354. p. F., BRINK, F. and BRONK,D. w, (1957), J . Neurochem., I : 245. , mid., 19: 981. DEJERINE,J. ( I ~ I I )Prrsse EVANS,J. G. (I964), Brit. wed. J., 2 : 9%. KING, E. S. J. (19491, AUST. N.Z. J. SURG.9 19: IOg. LAHRABEE, M. G. (1958), J . Neurochem, 2 : 81. sNYDER, E. N,, M ~ G. L. and ~ L ~ ~ R. W. (1975), Amrr. J . Sicrg., 130: 172.
THE INCIDENCE OF UNSUSPECTED PERIPHERAL ARTERIAL DISEASE AMONGST SURGICAL PATIENTS IN HONG KONG WONG,PETER LAMA N D G. B. ONG Department of Surgery, University of Hong Kong, Queen Mary Hospital, Hong Kong JOHN
A survey of surgical in-patients in Hong Kong has shown that subclinical peripheral arterial disease caused by atherosclerosis and detected by palpation is not uncommon and is similar i n incidence to th at reported in European populations. However, only a small proportion ‘of affected patients had any associated symptoms. Reduced or absent ankle and ulnar pulses occurred with the same frequency in our patients as in those i n Europe. Cigarette smoking does not appear to be associated with symptomatic arterial disease in the local population in Hong Kong.
PERIPHERAL arterial disease in the form of atherosclerosis is regarded as uncommon amongst the indigenous people of the East. However, there has been no substantiation of this impression. Arterial diseases reported from these countries usually belong to the inflammatory types, such as Takayasu’s or Buerger’s disease. This apparent rarity of atherosclerotic arterial disease is even more remarkable when one considers the high proportion of heavy cigarette smokers in the male population. Racial, dietary, and climatic factors have traditionally been thought responsible for the low incidence of this condition. I t has also been assumed that the shorter life expectancy in these developing countries has excluded the population from acquiring this degenerative disease. This explanation is no longer tenable, Reprints : Dr John Wong, address as ahove.
64
as the present mean life expectancy in Hong Kong is over 70 years. Other factors which may be more important in perpetuating the reported low incidence of over vascular disease are: (i) the more stoical Oriental patient may not complain of claudication ; (ii) the prevailing exercise pattern and low mean body weight may make claudication less severe ; (iii) the low incidence of any thrombotic tendency may make progression to gangrene less common; (iv) there is a low index of suspicion on the part of the medical attendant in diagnosing symptoms of vascular insufficiency ; and (v) there is a lack of trained personnel and facilities, so that fewer patients with vascular disease are referred for treatment. The purpose of this study has been to determine the incidence of occult peripheral arterial disease amongst surgical in-patients in a large teaching hospital in Hong Kong. The ,4TTST.
N.Z. J. SURG.,VOL.47-N0.
I,
FEBRUARY, 1977
~~
MACLEISH
CLAUDICATION OF THE CAUDA EQUINA D. G. MACLEISH Royal Melbourne Hospital The term “claudication o f the cauda equina” is examined. It has arisen from semantic errors, and a belief in ischamia f o r which there is no scientific evidence. fts use tends t o hamper rather than assist the investigation o f patients with obscure pain in the lower limb. A preferable alternative term, “atypical sciatica”, is suggested.
“To M Y GREAT SATISFACTION, the term took : and when The Spectator had stood godfather to it, any suspicion in the minds of respectable people that a knowledge of its parentage might have awakened was, of course, completely lulled.” With this quotation from Thomas Henry Huxley, the late E. S . J. King (1949) began his notable paper: The Lateral LymphoEpithelial Cyst Of The Neck (“branchial” cyst). H e pointed out that the term “branchial cyst” previously used for this structure was grossly misleading, represented an atiological error, and should be discarded. The neatness of a title, or its attractive alliteration, often gives it a prominence which it does not deserve, and disguises the confusion which may result from its adoption. This comniunication examines the term “claudication of the cauda equina” with regard to the justification for its use, and the practical implications resulting therefrom. Although derived from the Latin claudicare -to limp, the term “claudication” as now used implies ischzniia. Limping is an insignificant feature of patients described as having claudication, and claudication is not used to describe patients in whom a limp is prominent, hut not of ischzmic origin. The term “intermittent claudication of the spinal cord” was introduced by Dejerine ( I ~ I I ) ,who helieved that in the three cases he reported. exercise produced symptoms on the hasis of spinal cord ischzinia. Blau and Address for reprints : 96 Grattan Street, Carlton, Victoria 305.3.
62
Logue (1961), taking the cue from Dejerine, introduced the term “intermittent claudication of the cauda equina” to describe six patients who showed certain atypical features in a series of 300 consecutive cases of lumbar disc protrusion. Claudication of the spinal cord is said to be exceedingly rare, and the term has not caught on. On the other hand, claudication of the cauda equina seems to be flourishing, though why ischzmia of the cord should be less common than ischzmia of the cauda equina is hard to explain. ANATOMY A N D PHYSIOLOGY The blood supply of the cauda equina has not been measured, let alone any alterations of this produced by disease states. In the mouse, it has been found that exercising a single hind limb produces local increased vascularity in the corresponding segment of the spinal cord (Blau and Rushworth, 1958). In the rat, it has been observed that the rate of oxygen uptake by peripheral nerves is increased when the nerves are conducting impulses, and that the levels have parallelled the frequency of stimulation (Cranefield rt a&, 1957). The rate of oxygen uptake in excised sympathetic ganglia has been shown to rise during repeated stimulation (Larrabee, 1958). Little else is known about the effect of activity on the blood supply of the cauda equina. Considerable credence has been given to a conclusion that claudication time varies directly with oxygen tension (Evans, 1964). This conclusion has been quoted in several papers to indicate a relationship between “decreased AUST.N.Z.
1. SURG.,VOL.47-No.
I,
FEBRUARY, 1977
CLAUDICATION O F CAUDA EQUINA
blood oxygen level and increased pain” (Snyder et a& 1975). Evans did not measure blood oxygen levels. While a senior house officer at Oxford, he carried out an experiment on one patient who was subsequently shown to have adhesive arachnoiditis of the cauda equina. This patient was submitted to a fixed rate of work on a foot ergometer and allowed to breathe gases of varying oxygen tension, and reported when pain appeared in the exercised limb. Evans describes technical difficulty with part of the experiment, and his results are not statistically valid. , The anatomy of the lumbar spine, and the effects of posture, weight-hearing and walking on that region, are well known, yet seem to be overlooked by advocates of the term “claudication of the cauda equina”.
THE SYNDROME In 300 consecutive cases of lumbar disc protrusion, Blau and Logue (1961)found six patients in whom the pain and parzsthesia in the legs appeared related quantitatively to exercise. The pain in these patients was found to be in the lower back, huttock, thigh, lower leg, and sometimes the perineum. Although there was a relationship to exercise, there was also a relationship to prolonged standing. This latter has been somewhat glossed over. However. in their “typical case” it was a feature. Four months after operation, one such patient wrote : “I now enjoy walking and standing after manv years of walking and standitiq only when 1 could not avoid it . . . .” Frequently the protein content of the cerebrospinal fluid was raised. Five of the six patients were operated on, and in all an anterior disc protrusion with severe localized arachnoiditis was found Decompression, with or without removal of the protruded disc. resulted in complete relief of the intermittent symptoms. Rlau atid Logue postulated that when a person walks, there is an increased flow in the hlood vessels of the cauda equina. I n patients i n whom the volume of the spinal canal is reduced. thev believe that wch dilatation cqiiinot take place. so that a relative ischzmic neuritis occurs. Such an explanation overlooks the frequent situation where standinq alone induces the pain, and the frequent cases of compression AUST. N.Z. J.
SURG., VOL.
47-NO.
I,
FERRUARY, 1977
MACLEISH
(49 out of 50) where the symptoms are not related intermittently to walking. From the literature, one finds that where laminectomy has relieved the symptoms, the findings have been a narrow spinal canal, large disc protrusions either central or lateral, or spondylosis with enlarged facet joints and thickened ligamenta flava.
THEPROBLEM I t may be argued that since there is still a lot to learn about this condition, the name used is of little importance. However, the stimulus to submit this communication arose from an experience of now some 40 patients referred to a vascular surgery clinic in the belief that they were suffering from claudication of the cauda equina. Clearly the referring doctor believed in an ischzmic element, and often hoped that some vascular investigation or treatment might offer some relief. The first problem is one of differential diagnosis. The symptoms of the patients referred have eventually all been explained on the basis of spondylitis, disc Drotrusion, aortoiliac occlusive disease, or metastasis from carcinoma of the prostate. The problems of some of these patients have taken time to unravel, and some have had unproductive laminectomies. The concept of relative or absolute ischEmia of the cauda equina has retarded rather than accelerated the diagnostic processes. The second problem is that patients who clearly have significant aorto-iliac occlusive disease are often submitted to myelography. This has at times been unnecessary, and has on occasion made interpretation of subsequent arteriograms quite difficult. The third problem is that some patients with sciatica, albeit atypical, hut with perfectly normal leg pulses, have been submitted to aortopranhy i n the belief that this would yield some information regarding the blood supply of the cauda equina. This, of course, it cannot do.
CONCLUSIONS A scrutinv of the information from which the term “claudication of the cauda equina” has arisen makes it clear that many assumptions have been made. and some of these appear unwarranted. In Dractice, the vse of this term leads to a certain amount of confusion. To
63
WONG ET ALII
PERIPHERAL ARTERIAL DlSEASE I N HONG KONG
describe the syndrome in this way probably comes closer to the tail of the horse than is realized or was intended. It Seems Dreferable to use the term “atypical sciatica”. This term matches the present state of information about the condition, and does not prejudge further investigation into why certain positions of the lumbar spine, during standing or walking, cause more interference with the cauda equina than do others.
REFERE i i -c ES BLAU,J. N. and LOGUE,V. (1961),Lancet, I : 1081. BLAU, J. N. and RUSHWORTH, G. (1958), Brain, CRANEFIELD, 81: 354. p. F., BRINK, F. and BRONK,D. w, (1957), J . Neurochem., I : 245. , mid., 19: 981. DEJERINE,J. ( I ~ I I )Prrsse EVANS,J. G. (I964), Brit. wed. J., 2 : 9%. KING, E. S. J. (19491, AUST. N.Z. J. SURG.9 19: IOg. LAHRABEE, M. G. (1958), J . Neurochem, 2 : 81. sNYDER, E. N,, M ~ G. L. and ~ L ~ ~ R. W. (1975), Amrr. J . Sicrg., 130: 172.
THE INCIDENCE OF UNSUSPECTED PERIPHERAL ARTERIAL DISEASE AMONGST SURGICAL PATIENTS IN HONG KONG WONG,PETER LAMA N D G. B. ONG Department of Surgery, University of Hong Kong, Queen Mary Hospital, Hong Kong JOHN
A survey of surgical in-patients in Hong Kong has shown that subclinical peripheral arterial disease caused by atherosclerosis and detected by palpation is not uncommon and is similar i n incidence to th at reported in European populations. However, only a small proportion ‘of affected patients had any associated symptoms. Reduced or absent ankle and ulnar pulses occurred with the same frequency in our patients as in those i n Europe. Cigarette smoking does not appear to be associated with symptomatic arterial disease in the local population in Hong Kong.
PERIPHERAL arterial disease in the form of atherosclerosis is regarded as uncommon amongst the indigenous people of the East. However, there has been no substantiation of this impression. Arterial diseases reported from these countries usually belong to the inflammatory types, such as Takayasu’s or Buerger’s disease. This apparent rarity of atherosclerotic arterial disease is even more remarkable when one considers the high proportion of heavy cigarette smokers in the male population. Racial, dietary, and climatic factors have traditionally been thought responsible for the low incidence of this condition. I t has also been assumed that the shorter life expectancy in these developing countries has excluded the population from acquiring this degenerative disease. This explanation is no longer tenable, Reprints : Dr John Wong, address as ahove.
64
as the present mean life expectancy in Hong Kong is over 70 years. Other factors which may be more important in perpetuating the reported low incidence of over vascular disease are: (i) the more stoical Oriental patient may not complain of claudication ; (ii) the prevailing exercise pattern and low mean body weight may make claudication less severe ; (iii) the low incidence of any thrombotic tendency may make progression to gangrene less common; (iv) there is a low index of suspicion on the part of the medical attendant in diagnosing symptoms of vascular insufficiency ; and (v) there is a lack of trained personnel and facilities, so that fewer patients with vascular disease are referred for treatment. The purpose of this study has been to determine the incidence of occult peripheral arterial disease amongst surgical in-patients in a large teaching hospital in Hong Kong. The ,4TTST.
N.Z. J. SURG.,VOL.47-N0.
I,
FEBRUARY, 1977
~~
![[Intermittent claudication of cauda equina].](/assets/img/hold.png)
