- Email: [email protected]
Morphological analyses of paraspinal muscles: Comparison of progressive lumbar kyphosis (camptocormia) and narrowing of lumbar canal by disc protrusions
Neuromusc. Disord.. Vol. 3, No. 5/6, pp. 579~582, 1993
Copyright © 1994ElsevierScience Lid Printed in Great Britain. All rights reserved 0960-8966/93 $6.00+ .00
Pergamon
MORPHOLOGICAL ANALYSES OF PARASPINAL MUSCLES: COMPARISON OF PROGRESSIVE LUMBAR KYPHOSIS (CAMPTOCORMIA) AND NARROWING OF LUMBAR CANAL BY DISC PROTRUSIONS M. B. DEL1SLE,* M. L A R O C H E , t H. DUPONT,* P. ROCHAIX* and J. L. RUMEAU* *Service d'Anatomie et Cytologie Pathologiques, CHU Rangueil, F-31054 Toulouse cedex, France; t Service de Rhumatologie, CHU Rangueil, F-31054 Toulouse cedex, France
Abstract--Progressive lumbar kyphosis (camptocormia), a rare, usually familial disease in elderly patients, is characterized by inability to immobilize the lumbar spine in relation to the pelvis. CT scan reveals selective involvement of the spinal muscles with a heterogeneous appearance and is in favour of a primary disorder of these muscles. Our aim was to define the muscular lesions and clarify their nature in this particular disorder. Biopsies of the paravertebral muscles of 14 patients with lumbar kyphosis and of 20 operated on for disc herniation or narrowed lumbar canal, were studied by light microscopy, histochemistry and electron microscopy. In both groups, type l fibre predominance and atrophy of type 2 fibres were observed. Ragged-red fibres with abnormal mitochondria also occurred. The differential feature was increased frequency of extensive diffuse or lobulated fibrosis in camptocormia. Other features related to pathogenesis could not be determined.
Key words: Camptocormia, lumbar disorders, muscle biopsy, progressive lumbar kyphosis, vertebral muscle.
INTRODUCTION
PATIENTS AND METHODS
Kyphosis, usually dorsal, is frequent in patients over 70 yr and is associated with compensatory lordosis. L u m b a r kyphosis is much rarer, and in a standing position affected patients are unable to lock the lumbar spine in relation to the pelvis. The deformity disappears when they are in a recumbent position. The condition is seen mainly in women and there is often a family history of the condition. Radiological disc or bone lesions cannot be demonstrated in this disorder [1]. This spinal deformity is called camptocormia (kamptein: to bend; kormos: trunk) and appears to be due to weakness of the spinal muscles, which on CT scan are found to be selectively involved. Low density is observed quite early and the structure is heterogeneous [1, 2]. The aim of this study was to establish the occurrence of specific lesions in the muscles involved, and to determine the mechanism of the disease. Hence, biopsies of paraspinal muscles of patients with camptocormia and patients with other spinal disorders having a different CT scan image were compared.
G r o u p 1 (G1) was comprised of 14 patients (13 women and 1 man, aged 57-75 yr) with progressive lumbar kyphosis of a few weeks to 9 yr duration. All these patients in group 1 were examined between 1986 and 1993 and fulfilled the clinical and CT scan criteria of camptocormia [1]. None had other neurological disease or endocrine dysfunction. Biopsies of paravertebral muscles of these camptocormia patients were compared with biopsies of paravertebral muscles obtained during surgical procedure in 20 patients of group 2 (G2) suffering lumbar disc herniation and/or narrowing of the lumbar spinal canal. These 20 patients (12 women and 8 men) were aged from 20 to 78 yr: 9 were over 58 yr.
Muscle biopsy procedure Biopsies were taken from multifidus muscles, the deepest of the back muscles, attached to lumbar vertebrae transverse and spinous processes. Grouped a m o n g the transversospinal 579
580
M. B. DELISLE et al.
Table 1. Main pathological findings in lumbar kyphosis (camptocormia) and other lumbar disorders Patient
Age at biopsy
Mitochondrial
(yr)
abnormality
Adipose tissue
Camptocormia 1
57
0
2 3 4 5 6 7 8 9 10
60 61 61 62 64 65 66 68 70
0 + 0 + ND + + 0 0
11
71
+
+ +
12 13 14
71 74 75
0 0 0
Lumbar disorders 1 DH 2 3 4 5
6 7 8 9 10 11 12 13 14 15 16 17 18 19
20
DH DH DH DH DH DH DH DH DH DH DH DH+NLC NLC DH+NLC DH +NLC DH+NLC DH+NLC DH+NLC NLC
Endomysial fibrohyalinosis
0
0
+ + + + 0~ + + + + + + + +~++ 0-, + + + + + + + +
+ + + , nodular 0-~ + + + + + , nodular 0~ + + + + + , diffuse + + + ~ + + . diffuse 0 + - , + + + , nodular + + + , nodular + + , diffuse + + + . nodular
20
ND
+
0
36 39 40 41 42 44 45 47 50 53 58 61 64 67 69 70 71 74 78
ND ND ND ND ND ND ND ND 0 0 0 + + + 0 0 0 0 0
0 + + 0 + ---, + + + + + + + + + + + 4+ + + + 0 ++~++ + + + +~+ + + + + +
0 + , focal + + 0 0 0 + , focal 0 0 + , focal + + +~+ + 0 + 0 0 0-~+ + , focal + , focal
+
D H = disc herniation; N L C = narrowed lumbar canal; N D =electron microscopy not done. 0 = N o connective tissue change. + = Slight increase in connective tissue. + + = Moderate increase in connective tissue. + + + = M a r k e d increase in connective tissue.
muscles, separated from the erector spinal, these short muscles are innervated by the nerve exiting below the spinous process from which they originate. For light microscopy, sections from paraffin-embedded tissue were stained with haematoxylin-eosin (HE), periodic acid-Schiff (PAS) and Masson's trichrome. Histochemistry was performed on cryostat cross-sections using HE, PAS, Gomori modified trichrome, and the following reactions: ATPases at pH 9.4, 4.63 and 4.35, N A D H - T R and SDH [3]. Specimens for electron microscopy were fixed in 4% glutaraldehyde in cacodylate buffer, post-fixed in osmic acid and contrasted with uranyl acetate and lead citrate, and examined in a Hitachi 300 transmission electron microscope.
RESULTS
The biopsies of all patients showed a heterogeneous pattern of regions of muscle fibres of normal structure and regions where the muscle fibres presented varying degrees of change. Only in one case of group 1 patients (case 5) was an inflammatory infiltrate noted. In cases in which the ATPase reaction could undoubtly be analysed, more than 60% of fibres were type 1 (5 out of 5 cases of group 1 and 14 out of 20 cases of group 2). Atrophy of type 2 fibres was also observed in both groups. In biopsies showing great loss of muscle fibres and a marked increase in connective tissue, the ATPase reactions could not be analysed.
Progressive Lumbar Kyphosis
581
Target fibres occurred in 3 cases of group 1 and l 0 cases of group 2. Aggregation of nuclei and a few homogeneous cytoplasmic areas, pale and bluish on trichrome stain (hyalin inclusions) were seen. Ragged-red fibres occurred in less than 10% ofmuscle fibres (8 cases of group l; 10 cases of group 2). Some mitochondria were of abnormal irregular shape with coiled cristae and osmiophilic inclusions in both groups. Paracrystalline inclusions were not found. In a few cases of both groups, mitochondria were small and appeared to be abnormally densely packed. Electron microscopy sometimes showed small rods, streaming of the Z-lines, accumulation of lipid and cytoplasmic nuclear invaginations. The only striking difference between the two groups was the increase in connective tissue. In the biopsies of patients with camptocormia (group 1) irregular distribution of involuted muscle fibres and a marked increase in connective tissue were noted. These changes were not related to the patients' age nor to the duration of the illness. The fibrosis was often extensive involving most of a fascicle and sparing only a few muscle fibres which presented degenerative changes (Fig. lb). In the biopsies of patients of group 2, fibrosis was not a constant finding. When present it occurred along the septa and at the periphery of the muscle fascicles. Only in a few cases was the fibrosis intense and associated with global atrophy of the muscle fibres (Fig. l a). DISCUSSION Progressive lumbar kyphosis appears to be due to weakness of the spinal muscles. Its appearance on CT scan, and the absence of clinical or CT scan abnormalities of other muscles, are in favour of primary involvement of the paravertebral muscle [1, 2]. The clinical manifestations of camptocormia differ from those of other lumbar disorders, in the particular anterior curvature of the trunk which disappears in the decubitus position, increases with tiredness and is associated with the inability to extend the trunk in the ventral decubitus position. In this disease CT scan abnormalities of multifidus muscles are observed at all levels of the spine. These muscles are thought to be unisegmentally innervated. The absence of neurological disease, inflammatory conditions and endocrine disorders in camptocormia would point to a primary dysfunction of these muscles [l, 2, 4, 5]. To explore this hypothesis, we compared muscle biopsies from
Fig. 1. Paraffin-embedded sections, trichrome, x 40. (a) Group 2 (other lumbar disorders), case 4. Fibrosis affects perimysial and endomysialtissue, separating atrophic fibres. (b) Group I (lumbar kyphosis),case 6. Fibrosis is lobular and follows the pattern of pre-existingmusclecells; a few random muscle fibres are spared. patients with progressive lumbar kyphosis and those with pain due to other lumbar disorders. N o r m a l muscle was rarely seen in either group. The multifidus muscle, the innermost and shortest of paraspinal muscles, is often con-
582
M.B. DELISLEet al.
sidered to be devoid of specific lesions, especially in disc protrusion. O u r study confirms the changes described previously in these muscles, n a m e l y target fibres or pseudocores a n d type 2 muscle fibre a t r o p h y [6, 7]. They m a y be related to aging [8]. M i t o c h o n d r i a l changes, which were striking in c a m p t o c o r m i a , have n o t been described as c o m m o n in l u m b a r disorders, b u t occurred in both groups, especially in patients aged over 50 yr in g r o u p 2. M i t o c h o n d r i a l m y o p a t h y has been i n c r i m i n a t e d as a predisposing c o n d i t i o n in some muscle diseases [9]. The lack o f paracrystalline inclusions a n d the regular positivity of the cytochrome oxidase reaction in the two cases in which it could be performed are in favour o f a secondary pathology b u t whose m e c h a n i s m is unclear, m a y be due to aging, ischaemia or i n f l a m m a t i o n [10-12]. The i n f l a m m a t o r y infiltrate has previously been i n c r i m i n a t e d in c a m p t o c o r m i a [4] b u t in this study it was seen in only one case o f c a m p t o c o r mia. The m a i n microscopic change in c a m p t o c o r mia was the increase o f fibrous tissue, frequently with a l o b u l a r pattern, a n d a m o n g s t which persisted n o r m a l sized degenerative fibres. C o m paring the two groups, this could n o t be considered to be a n o r m a l feature related to aging n o r secondary to muscle d y s f u n c t i o n of l u m b a r osteoarticular origin. Nevertheless, the etiopathogenesis o f this muscle i n v o l v e m e n t in c a m p t o c o r m i a r e m a i n s obscure. Acknowledgements--We wish to thank Professor J. Lagarrigue for surgicalbiopsies,Mrs L. Larrie for technicalassistance and Ms N. Crowte for preparation of the manuscript. The
financial support of the Association Franqaise contre les Myopathies (AFM) is gratefully acknowledged. REFERENCES
1. LarocheM, Delisle M B, Mazi~res B, et aL Myopathie tardive localis6e aux muscles spinaux: une cause de cyphose lombaire acquise de l'adulte. Rev Rhum 1991; 58:829 838. 2. LarocheM, Rousseau H, Mazi/~resB, Bonaf6A, Joffre F, Arlet J. Int6r6t de la tomodensitom6trie dans la pathologie musculaire. Observations personnelles et revue de la litterature. Rev Rhum 1989: 56: 433-439. 3. Dubowitz V, Brooke M H. Muscle Biopsy." a Modern Approach. Philadelphia: Saunders, 1973. 4. Hilliquin P, MenkesC J, Laoussadi S, Job-Deslandre C, Serratrice G. Camptocormie du sujet ~g6. Une nouvelle entit6 par atteinte des muscles paravert6braux? Rev Rhum Mal Ost~oartic 1992; 59: 16%175. 5. Poullin P, Daumen-L6gre V, Serratrice G. La camptocormie du sujet ~ig6:myopathie ou dystonie musculaire? Rev Rhum 1993; 60: 159-161. 6. Ford D, Bagnall K M, McFadden K D, Greenhill B, Raso J. Analysis of vertebral muscle obtained during surgery for correction of a lumbar disc disorder. Acta Anat 1983; 116:152 157. 7. Mattila M, Hurme M, Alaranta H, et al. The multifidus muscle in patients with lumbar disc herniation. A histochemical and morphometric analysis of intraoperative biopsies. Arch Neurol 1986; 11: 732-738. 8. Aniansson A, Medberg M, Henning G B, Grimby G. Muscle morphology, enzymatic activity and muscle strength in elderly men: a follow-up study. Must'& Nerve 1986; 9: 585-591. 9. Harle J R, Pellissier J F, Desnuelle C, Disdier P, Figarella-Branger D, Weiller P J. Polymalgia rheumatica and mitochondrial myopathy: clinicopathological and biochemical studies in five cases. Am J Med 1992: 92: 167-172. 10. Heffner R R, Barron A. The early effects of ischemia upon skeletal muscle mitochondria. J Neurol Sci 1978: 38:295 315. II. Sengers R C A, Stadhouders A M. Secondary mitochondrial pathology. J lnher Metab Dis 1987; 10: 98- 104. 12. Kaminsky P, Klein M, Robin-Lherbier B, et al. Atteinte mitochondriale secondaire i l'inflammation au cours des polymyosites:deux observations. Presse Med 1992; 21: 1279-1282.
Copyright © 1994ElsevierScience Lid Printed in Great Britain. All rights reserved 0960-8966/93 $6.00+ .00
Pergamon
MORPHOLOGICAL ANALYSES OF PARASPINAL MUSCLES: COMPARISON OF PROGRESSIVE LUMBAR KYPHOSIS (CAMPTOCORMIA) AND NARROWING OF LUMBAR CANAL BY DISC PROTRUSIONS M. B. DEL1SLE,* M. L A R O C H E , t H. DUPONT,* P. ROCHAIX* and J. L. RUMEAU* *Service d'Anatomie et Cytologie Pathologiques, CHU Rangueil, F-31054 Toulouse cedex, France; t Service de Rhumatologie, CHU Rangueil, F-31054 Toulouse cedex, France
Abstract--Progressive lumbar kyphosis (camptocormia), a rare, usually familial disease in elderly patients, is characterized by inability to immobilize the lumbar spine in relation to the pelvis. CT scan reveals selective involvement of the spinal muscles with a heterogeneous appearance and is in favour of a primary disorder of these muscles. Our aim was to define the muscular lesions and clarify their nature in this particular disorder. Biopsies of the paravertebral muscles of 14 patients with lumbar kyphosis and of 20 operated on for disc herniation or narrowed lumbar canal, were studied by light microscopy, histochemistry and electron microscopy. In both groups, type l fibre predominance and atrophy of type 2 fibres were observed. Ragged-red fibres with abnormal mitochondria also occurred. The differential feature was increased frequency of extensive diffuse or lobulated fibrosis in camptocormia. Other features related to pathogenesis could not be determined.
Key words: Camptocormia, lumbar disorders, muscle biopsy, progressive lumbar kyphosis, vertebral muscle.
INTRODUCTION
PATIENTS AND METHODS
Kyphosis, usually dorsal, is frequent in patients over 70 yr and is associated with compensatory lordosis. L u m b a r kyphosis is much rarer, and in a standing position affected patients are unable to lock the lumbar spine in relation to the pelvis. The deformity disappears when they are in a recumbent position. The condition is seen mainly in women and there is often a family history of the condition. Radiological disc or bone lesions cannot be demonstrated in this disorder [1]. This spinal deformity is called camptocormia (kamptein: to bend; kormos: trunk) and appears to be due to weakness of the spinal muscles, which on CT scan are found to be selectively involved. Low density is observed quite early and the structure is heterogeneous [1, 2]. The aim of this study was to establish the occurrence of specific lesions in the muscles involved, and to determine the mechanism of the disease. Hence, biopsies of paraspinal muscles of patients with camptocormia and patients with other spinal disorders having a different CT scan image were compared.
G r o u p 1 (G1) was comprised of 14 patients (13 women and 1 man, aged 57-75 yr) with progressive lumbar kyphosis of a few weeks to 9 yr duration. All these patients in group 1 were examined between 1986 and 1993 and fulfilled the clinical and CT scan criteria of camptocormia [1]. None had other neurological disease or endocrine dysfunction. Biopsies of paravertebral muscles of these camptocormia patients were compared with biopsies of paravertebral muscles obtained during surgical procedure in 20 patients of group 2 (G2) suffering lumbar disc herniation and/or narrowing of the lumbar spinal canal. These 20 patients (12 women and 8 men) were aged from 20 to 78 yr: 9 were over 58 yr.
Muscle biopsy procedure Biopsies were taken from multifidus muscles, the deepest of the back muscles, attached to lumbar vertebrae transverse and spinous processes. Grouped a m o n g the transversospinal 579
580
M. B. DELISLE et al.
Table 1. Main pathological findings in lumbar kyphosis (camptocormia) and other lumbar disorders Patient
Age at biopsy
Mitochondrial
(yr)
abnormality
Adipose tissue
Camptocormia 1
57
0
2 3 4 5 6 7 8 9 10
60 61 61 62 64 65 66 68 70
0 + 0 + ND + + 0 0
11
71
+
+ +
12 13 14
71 74 75
0 0 0
Lumbar disorders 1 DH 2 3 4 5
6 7 8 9 10 11 12 13 14 15 16 17 18 19
20
DH DH DH DH DH DH DH DH DH DH DH DH+NLC NLC DH+NLC DH +NLC DH+NLC DH+NLC DH+NLC NLC
Endomysial fibrohyalinosis
0
0
+ + + + 0~ + + + + + + + +~++ 0-, + + + + + + + +
+ + + , nodular 0-~ + + + + + , nodular 0~ + + + + + , diffuse + + + ~ + + . diffuse 0 + - , + + + , nodular + + + , nodular + + , diffuse + + + . nodular
20
ND
+
0
36 39 40 41 42 44 45 47 50 53 58 61 64 67 69 70 71 74 78
ND ND ND ND ND ND ND ND 0 0 0 + + + 0 0 0 0 0
0 + + 0 + ---, + + + + + + + + + + + 4+ + + + 0 ++~++ + + + +~+ + + + + +
0 + , focal + + 0 0 0 + , focal 0 0 + , focal + + +~+ + 0 + 0 0 0-~+ + , focal + , focal
+
D H = disc herniation; N L C = narrowed lumbar canal; N D =electron microscopy not done. 0 = N o connective tissue change. + = Slight increase in connective tissue. + + = Moderate increase in connective tissue. + + + = M a r k e d increase in connective tissue.
muscles, separated from the erector spinal, these short muscles are innervated by the nerve exiting below the spinous process from which they originate. For light microscopy, sections from paraffin-embedded tissue were stained with haematoxylin-eosin (HE), periodic acid-Schiff (PAS) and Masson's trichrome. Histochemistry was performed on cryostat cross-sections using HE, PAS, Gomori modified trichrome, and the following reactions: ATPases at pH 9.4, 4.63 and 4.35, N A D H - T R and SDH [3]. Specimens for electron microscopy were fixed in 4% glutaraldehyde in cacodylate buffer, post-fixed in osmic acid and contrasted with uranyl acetate and lead citrate, and examined in a Hitachi 300 transmission electron microscope.
RESULTS
The biopsies of all patients showed a heterogeneous pattern of regions of muscle fibres of normal structure and regions where the muscle fibres presented varying degrees of change. Only in one case of group 1 patients (case 5) was an inflammatory infiltrate noted. In cases in which the ATPase reaction could undoubtly be analysed, more than 60% of fibres were type 1 (5 out of 5 cases of group 1 and 14 out of 20 cases of group 2). Atrophy of type 2 fibres was also observed in both groups. In biopsies showing great loss of muscle fibres and a marked increase in connective tissue, the ATPase reactions could not be analysed.
Progressive Lumbar Kyphosis
581
Target fibres occurred in 3 cases of group 1 and l 0 cases of group 2. Aggregation of nuclei and a few homogeneous cytoplasmic areas, pale and bluish on trichrome stain (hyalin inclusions) were seen. Ragged-red fibres occurred in less than 10% ofmuscle fibres (8 cases of group l; 10 cases of group 2). Some mitochondria were of abnormal irregular shape with coiled cristae and osmiophilic inclusions in both groups. Paracrystalline inclusions were not found. In a few cases of both groups, mitochondria were small and appeared to be abnormally densely packed. Electron microscopy sometimes showed small rods, streaming of the Z-lines, accumulation of lipid and cytoplasmic nuclear invaginations. The only striking difference between the two groups was the increase in connective tissue. In the biopsies of patients with camptocormia (group 1) irregular distribution of involuted muscle fibres and a marked increase in connective tissue were noted. These changes were not related to the patients' age nor to the duration of the illness. The fibrosis was often extensive involving most of a fascicle and sparing only a few muscle fibres which presented degenerative changes (Fig. lb). In the biopsies of patients of group 2, fibrosis was not a constant finding. When present it occurred along the septa and at the periphery of the muscle fascicles. Only in a few cases was the fibrosis intense and associated with global atrophy of the muscle fibres (Fig. l a). DISCUSSION Progressive lumbar kyphosis appears to be due to weakness of the spinal muscles. Its appearance on CT scan, and the absence of clinical or CT scan abnormalities of other muscles, are in favour of primary involvement of the paravertebral muscle [1, 2]. The clinical manifestations of camptocormia differ from those of other lumbar disorders, in the particular anterior curvature of the trunk which disappears in the decubitus position, increases with tiredness and is associated with the inability to extend the trunk in the ventral decubitus position. In this disease CT scan abnormalities of multifidus muscles are observed at all levels of the spine. These muscles are thought to be unisegmentally innervated. The absence of neurological disease, inflammatory conditions and endocrine disorders in camptocormia would point to a primary dysfunction of these muscles [l, 2, 4, 5]. To explore this hypothesis, we compared muscle biopsies from
Fig. 1. Paraffin-embedded sections, trichrome, x 40. (a) Group 2 (other lumbar disorders), case 4. Fibrosis affects perimysial and endomysialtissue, separating atrophic fibres. (b) Group I (lumbar kyphosis),case 6. Fibrosis is lobular and follows the pattern of pre-existingmusclecells; a few random muscle fibres are spared. patients with progressive lumbar kyphosis and those with pain due to other lumbar disorders. N o r m a l muscle was rarely seen in either group. The multifidus muscle, the innermost and shortest of paraspinal muscles, is often con-
582
M.B. DELISLEet al.
sidered to be devoid of specific lesions, especially in disc protrusion. O u r study confirms the changes described previously in these muscles, n a m e l y target fibres or pseudocores a n d type 2 muscle fibre a t r o p h y [6, 7]. They m a y be related to aging [8]. M i t o c h o n d r i a l changes, which were striking in c a m p t o c o r m i a , have n o t been described as c o m m o n in l u m b a r disorders, b u t occurred in both groups, especially in patients aged over 50 yr in g r o u p 2. M i t o c h o n d r i a l m y o p a t h y has been i n c r i m i n a t e d as a predisposing c o n d i t i o n in some muscle diseases [9]. The lack o f paracrystalline inclusions a n d the regular positivity of the cytochrome oxidase reaction in the two cases in which it could be performed are in favour o f a secondary pathology b u t whose m e c h a n i s m is unclear, m a y be due to aging, ischaemia or i n f l a m m a t i o n [10-12]. The i n f l a m m a t o r y infiltrate has previously been i n c r i m i n a t e d in c a m p t o c o r m i a [4] b u t in this study it was seen in only one case o f c a m p t o c o r mia. The m a i n microscopic change in c a m p t o c o r mia was the increase o f fibrous tissue, frequently with a l o b u l a r pattern, a n d a m o n g s t which persisted n o r m a l sized degenerative fibres. C o m paring the two groups, this could n o t be considered to be a n o r m a l feature related to aging n o r secondary to muscle d y s f u n c t i o n of l u m b a r osteoarticular origin. Nevertheless, the etiopathogenesis o f this muscle i n v o l v e m e n t in c a m p t o c o r m i a r e m a i n s obscure. Acknowledgements--We wish to thank Professor J. Lagarrigue for surgicalbiopsies,Mrs L. Larrie for technicalassistance and Ms N. Crowte for preparation of the manuscript. The
financial support of the Association Franqaise contre les Myopathies (AFM) is gratefully acknowledged. REFERENCES
1. LarocheM, Delisle M B, Mazi~res B, et aL Myopathie tardive localis6e aux muscles spinaux: une cause de cyphose lombaire acquise de l'adulte. Rev Rhum 1991; 58:829 838. 2. LarocheM, Rousseau H, Mazi/~resB, Bonaf6A, Joffre F, Arlet J. Int6r6t de la tomodensitom6trie dans la pathologie musculaire. Observations personnelles et revue de la litterature. Rev Rhum 1989: 56: 433-439. 3. Dubowitz V, Brooke M H. Muscle Biopsy." a Modern Approach. Philadelphia: Saunders, 1973. 4. Hilliquin P, MenkesC J, Laoussadi S, Job-Deslandre C, Serratrice G. Camptocormie du sujet ~g6. Une nouvelle entit6 par atteinte des muscles paravert6braux? Rev Rhum Mal Ost~oartic 1992; 59: 16%175. 5. Poullin P, Daumen-L6gre V, Serratrice G. La camptocormie du sujet ~ig6:myopathie ou dystonie musculaire? Rev Rhum 1993; 60: 159-161. 6. Ford D, Bagnall K M, McFadden K D, Greenhill B, Raso J. Analysis of vertebral muscle obtained during surgery for correction of a lumbar disc disorder. Acta Anat 1983; 116:152 157. 7. Mattila M, Hurme M, Alaranta H, et al. The multifidus muscle in patients with lumbar disc herniation. A histochemical and morphometric analysis of intraoperative biopsies. Arch Neurol 1986; 11: 732-738. 8. Aniansson A, Medberg M, Henning G B, Grimby G. Muscle morphology, enzymatic activity and muscle strength in elderly men: a follow-up study. Must'& Nerve 1986; 9: 585-591. 9. Harle J R, Pellissier J F, Desnuelle C, Disdier P, Figarella-Branger D, Weiller P J. Polymalgia rheumatica and mitochondrial myopathy: clinicopathological and biochemical studies in five cases. Am J Med 1992: 92: 167-172. 10. Heffner R R, Barron A. The early effects of ischemia upon skeletal muscle mitochondria. J Neurol Sci 1978: 38:295 315. II. Sengers R C A, Stadhouders A M. Secondary mitochondrial pathology. J lnher Metab Dis 1987; 10: 98- 104. 12. Kaminsky P, Klein M, Robin-Lherbier B, et al. Atteinte mitochondriale secondaire i l'inflammation au cours des polymyosites:deux observations. Presse Med 1992; 21: 1279-1282.