:Acta Nurochirurgica
Acta Neurochir (Wien) (1991) 110:160-165
9 Springer-Verlag 1991 Printed in Austria
Intradural Disc Herniations Pathogenesis, Clinical Picture, Diagnosis and Treatment A. Yildizhan 1, A. Pa~ao~lu 2, T. Okten 3, N. Ekinci 4, K. Aycan 4, and O. Aral 1 ~Department of Neurosurgery, Vakif Gureba Hospital, Istanbul, and Departments of 2Neurosurgery, 3Pathology, and 4Anatomy, Erciyes University, School of Medicine, Kayseri, Turkey
Summary The relatively rare occurrence and uncertainty about pathogenesis of intradurally displaced disc herniations stimulated an anatomico-pathological study into intradural disc herniations. The relation between the ventral dura and posterior longitudinal ligament in the cervical, thoracic, lumbar and sacral regions were examined macroscopically and microscopically,and ventrai and dorsal dural thickness was compared in 20 adult autopsies on patients who died from various causes; in addition, 20 late abortions and newborn cadavers were investigated in the same way. In this study, a total of 40 autopsies has shown that the ventral dura is most frequently and firmly attached to the posterior longitudinal ligament at the L 4-L 5 level and these adhesions may be congenital. In the adult cadavers dorsal dura was found to be thicker than the ventral dura in the lumbar and lower cervical interspaces. Three personal clinical cases of intradurally herniated disc prolapse are shortly described and the diagnosis and management of this pathology discussed.
Keywords:Intervertebral disc displacement; intradural disc herniation; intradural disc rupture; lumbar disc; herniated nucleus pulposus.
Introduction As a very rare pathology, the first report o f a n i n t r a d u r a l h e r n i a t i o n of a n intervertebral disc was presented by W a l t e r E. D a n d y 4 in 1942. D a n d y , in his article related the characteristics of the history a n d neurological findings of this clinical p h e n o m e n o n . I n 1981 Smith Is reported two cases a n d also specified the p u b l i c a t i o n of 43 cases in the literature. The cases have usually been seen at L 4 - 5 a n d L 3-4, b u t they have also been reported unusually at other levels 3, 5, 6, 8,1 ~, 13,16 T h e i n t r a d u r a l finding o f i n t e r v e r t e b r a l disc m a t e r i a l is a rare occurrence. O n l y if the nucleus p u l p o s u s ruptures the a n n u l u s fibrosus, the posterior l o n g i t u d i n a l
ligament, a n d the d u r a mater, can a free f r a g m e n t of disc material migrate into the s u b a r a c h n o i d space. But the m e c h a n i s m of this event a n d the frequent preference o f L 4 - L 5 interspace were n o t well u n d e r s t o o d . These questions a n d three patients with i n t r a d u r a l disc hern i a t i o n treated in our clinics provided the stimulus for a n a n a t o m i c o - p a t h o l o g i c a l investigation of the relation between the spinal dura, posterior l o n g i t u d i n a l ligam e n t a n d d u r a l thickness at all levels t h r o u g h o u t the spinal canal.
Materials and Methods Forty consecutive autopsies were performed during the years 1986 to 1989 in the Neurosurgical, Pathology and Anatomy Departments of Erciyes University Medical School. There were 20 adult cadavers with no history of low back pain or sciatica, and 20 late abortions and newborn cadavers totalling 40 autopsies. In the prone position the spinous processes, the laminae, the articular facets and the pedicles were removed. First, a transverse cross section was made at every level of both the posterior longitudinal ligament and the annulus fibrosus from cervical to sacral regions for obtaining pathological specimensand then the dura was opened longitudinally and the spinal cord removed after section of the roots. Finally the dura was cut away except for the anterior wall which then could be lifted off from the posterior longitudinal ligament at the same levels. Loose or firm connections or dense adhesions between the dura, the ligament, and the annulus were noted at every level. Following macroscopical evaluation, sequential sections were made and stained with haematoxylin and eosin (HE). The relation between the ventral dura and the posterior longitudinal ligament were examined, and ventral and dorsal thickness was compared microscopically.
Results Only loose c o n n e c t i o n s were f o u n d between the d u r a a n d the ligament at m o s t levels. But at 43 levels there
A. Yildizhan etal.: Intradural Disc Herniations
161
Table 1. Incidence and Location of Separable and Nonseparable Adhesions Between Ventral Dura and Posterior Longitudinal Ligament in 40 Autopsies
Levels
c2-c3 C3-C4 C4-C5 C5-C6 C6-C7 C 7-T 1 T l-T2 T2-T3 T3-T4 T4-T5 TS-T6 T6T7 TT-T8 TS-T9 T 9-T 10 T10-Tll T 11-T 12 T 12-L 1 LI-L2 L2-L3 L3-L4 L4-L 5 L 5-S 1
Adult cadavers
Abortion and newborn cadavers
No connec,
Loose connec,
1 3 1 1 2 3 5 4 6 6 5 4 1 1 1 2 1 1 2 -
16 18 16 13 12 16 15 15 16 13 13 15 15 16 17 17 16 16 16 13 5 1 5
Dense adhes, 3 1 1 4 4 1 1 1 1 1 2 1 1 1 2 2 3 11 12 12
Firm connec,
No connec,
Loose connec,
Dense adhes,
Firm connec.
1 2 3 1 1 1 1 1 1 1 1 2 4 7 3
2 4 1 1 2 4 4 4 8 7 4 2 1 2 2 3 2 2 1 -
17 17 15 16 15 16 16 16 16 12 12 16 18 18 16 17 16 17 15 15 14 10 15
2 1 1 2 3 1 1 1 1 1 1 1 2 3 4 7 4
l 1 1 1 1 1 1 2 3 1
w e r e v e r y f i r m c o n n e c t i o n s b e t w e e n t h e d u r a , t h e lig-
ble 1) a n d less f r e q u e n t l y a t t h e L 3 - L 4 , L 5 - S 1 levels,
a m e n t , a n d t h e a n n u l u s ( T a b l e 1). T h e s e i n t i m a t e c o n -
a n d i n t h e l o w e r c e r v i c a l i n t e r s p a c e s ( F i g . 1 C).
nections could not be divided by blunt dissection. Non-
Among
20 a d u l t s a n d 20 o t h e r s , f i r m c o n n e c t i o n s
separable connections of this kind were found at the
that could not be separated bluntly were found in a
L 4 - L 5 i n t e r s p a c e i n 7 a d u l t s a n d 3 n e w b o r n s . I n sev-
t o t a l o f 10 c a s e s a t t h e L 4 - L 5 level a n d less f r e q u e n t l y
eral other cases dense adhesions were observed in the
a t s o m e o t h e r levels (Figs. 1 D a n d 2).
lower lumbar, occasionally lower thoracic, and some-
Ventral and dorsal dural thickness were investigated
times lower cervical interspaces; but these could be
microscopically and the comparable results were sum-
separated bluntly. The findings are summarized in Ta-
m a r i z e d in T a b l e 2. S o m e p h o t o g r a p h s
b l e 1.
obtained during microscopical study are also presented
T h e r o u t i n e h i s t o l o g i c a l s e c t i o n s o f v a r i o u s levels
which were
( F i g s . 3 a n d 4).
o b t a i n e d a t a u t o p s y w e r e r e - e x a m i n e d a n d s i m i l a r results were observed in the microscopical study. The ventral dura was not connected to the posterior long i t u d i n a l l i g a m e n t a t 106 levels i n t o t a l b e t w e e n t h e C 3 - C 4 a n d t h e L 2 - L 3 i n t e r s p a c e s (Fig. 1 A ) . T h e r e w e r e l o o s e c o n n e c t i o n s i n a t o t a l o f 670 levels between the ventral dura and the posterior longitudinal ligament in the cervical, thoracic, and lumbar regions ( F i g s . 1 B a n d 4). Dense adhesions which could be separated bluntly w e r e o b s e r v e d m o s t f r e q u e n t l y a t t h e L 4 - L 5 level ( T a -
Case Reports Case 1. A 57-year-old housewife had experienced moderate episodes of low back pain for approximately two years. Three days before hospitalization very severe pains and numbness started in her back and both legs after lifting a heavy object and two days later these pains were followed by urinary and faecal incontinence. Neurological examination revealed hypaesthesia and hypalgesia of L 5 bilaterally and all sacral dermatomes and severe weakness of flexor and extensor movements of the feet bilaterally. Achilles tendon reflexes were absent. Iohexol myelography revealed a complete block at L 4-5.
162
A. Yildizhan et al.: Intradural Disc Herniations
Fig. 1. Photomicrographs of a transverse section of the anterior wall of the spinal canal. A) The ventral dura (VD) is not connected to the posterior longitudinal ligament (PLL) at the L 2 - L 3 level. B) Loosely connected VD and P L L at the L 5-S 1 level. C) Dense adhesions between the VD and the P L L at the L 3 - L 4 level. D) The VD and the P L L are firmly connected at the L 4 - L 5 level (HE x 32)
A. Yildizhan etal.: Intradural Disc Herniations
Fig. 2. The ventral dura (VD) and the posterior longitudinal ligament (PLL) are intimately connected at the C 6-C 7 level (HE x 32)
163
Fig. 3. Three photomicrographs form a complete photograph. The dorsal dura (DD) is thicker than the ventral dura (VD) at the C 5-C 6 interspace (HE x 32)
A total laminectomy was performed at L 4 and a half at L5. This revealed that the dura was anteriorly adherent by scar tissue to the posterior longitudinal ligament and that the disc material was extruding into the dural sac. When the dura was opened posteriorly an irregular mass of disc was seen in the dural sac compressing the nerve roots. After removal of the disc, a rent approximately 1 x 0.7cm communicating with the L4-5 interspace was found in the ventral wall of the dura. This could not be closed. The patient made an uneventful recovery. One day after operation radicular pain had resolved and within two months she had regained normal sensation and strength. Her bladder and bowel functions were normal in the following fifth months. Case 2. A 70-year-old man was complaining for 11 months of fluctuating low back pain. Four days before hospitalization, he suffered from acute lumbar and radicular pain on both sides but more severe on the right side. He had paraparesis and urinary and faecal retention. Pantopaque myelography showed a block round in shape across the L 1-2 level. We performed an exploratory laminectomy at L 1-2 and intradural disc material was removed. We noticed epidural scar tissue at L 1-2. The dura was firmly adherent both to the underlying disc mass anteriorly and to the longitudinal ligament Fig. 4. Two photomicrographs make a complete photograph. The dorsal dura (DD) is thicker than the ventral dura (VD), and the VD and the posterior longitudinal ligament (PLL) are loosely connected at the L 5-S 1 level (HE x 32)
A. Yildizhan etal.: Intradural Disc Herniations
164 Table 2. Proportional Results of Ventral and Dorsal Dural Thickness in Each Interspace
Levels
Ventral dural thickness proportional to dorsal dural thickness Adult cadavers
C2-C3 C 3-C 4 C4-C 5 C 5-C 6 C6-C7 C7-T 1 T 1-T 2 T 2-T 3 T 3-T 4 T4-T 5 T5-T6 T 6-T 7 T 7-T 8 T 8-T 9 T 9-T 10 T 10-T 11 T 11-T 12 T 12-L 1 L1-L2 L2-L3 L3-L4 L4-L 5 L5-S 1
Abortion and newborn cadavers
More
Equal
Less
More
Equal
Less
1 1 1
18 20 18 17 17 18 20 20 20 19 20 20 20 20 20 20 20 19 18 17 16 15 15
1 2 3 3 2 1 2 3 4 5 4
1 1 1 -
19 20 20 20 19 20 20 20 20 20 19 20 20 20 20 20 20 20 20 20 20 20 19
1 1
posteriorly. The patient recovered slowly until he could walk unaided within 4 months. Bowel function was normal after 4 months, and bladder function within 8 months after the operation. Case 3. The history of this 53-year-old man was very similar to that of case 2. However his neurological dysfunction was not so severe. He had right leg weakness and atrophy, right radicular pain and L4 hypalgesia. He had no sphincter disturbance. Pantopaque myelography showed an incomplete block at the L 3M interspace. An exploratory laminectomy was permormed and we noticed an intradural disc rupture. Epidural scar tissue was less prominent compared to case 2. After the operation, the patient recovered excellently. The radicular pain resolved, and sensory deficiency and leg weakness improved within 6 weeks.
e r i z e d t o m o g r a p h y . E x i s t e n c e o f m a c r o p h a g e s in t h e c e r e b r o s p i n a l fluid o b t a i n e d at m y e l o g r a p h y m a y also s u g g e s t t h e d i a g n o s i s a t t h e p r e - o p e r a t i v e s t a g e 15. T h e m o s t c o m m o n m y e l o g r a p h i c f i n d i n g is t o t a l b l o c k t o t h e f l o w o f t h e c o n t r a s t m e d i u m 7' 11,15. T h e p r e s e n c e o f a n i r r e g u l a r l y d e l i n e a t e d filling d e f e c t o r t h e a p p e a r a n c e o f a c i r c u m s c r i b e d m a s s a t t h e level o f t h e d i s c s p a c e at myelography should suggest an intradural disc rupture. R a d i c u l a r pain a n d neurological deficit are charct e r i s t i c a l l y s e v e r e , b u t t h i s p h e n o m e n o n a t L 1 a n d bel o w c a r r i e s a g o o d p r o g n o s i s 9'15' 19. I n t h e s e c a s e s t h e f u n c t i o n a l r e c o v e r y is s o m e w h a t s l o w b u t e x c e l l e n t a s a rule. I f t h e p a t i e n t h a s b l a d d e r a n d b o w e l c o m p l a i n t s ,
Discussion
p r o m p t s u r g e r y is i m p o r t a n t . A n o p e r a t i n g m i c r o s c o p e
A l t h o u g h n e a r l y 50 y e a r s h a v e p a s s e d s i n c e p u b l i c a t i o n o f t h e t w o c a s e s b y D a n d y 4, n o m a j o r n e w as-
is i n v a l u a b l e d u r i n g s u r g e r y , p a r t i c u l a r l y w h e n r e m o v i n g t h e d i s c m a s s a t t h e c o n u s level.
pects regarding aetiology, incidence, characteristics of
I t is n o t e a s y t o e x p l a i n h o w n u c l e u s p u l p o s u s p e r -
the history, neurological findings, and postoperative
f o r a t e s t h e d u r a m a t e r a n d w h y t h i s p h e n o m e n o n oc-
course of the lumbar intradural disc ruptures have been
c u r s m o s t f r e q u e n t l y a t t h e L 4 - L 5 level 9' 15. Some histology and anatomy textbooks state that
d e s c r i b e d in s u b s e q u e n t p u b l i c a t i o n s . that intra-
the narrow epidural space contains loose connective
dural disc rupture can be diagnosed pre-operatively by
and fatty tissue and venous plexus, and that the spinal
utilizing metrizamide enhancement of spinal comput-
d u r a m a t e r is a t t a c h e d o t t h e c i r c u m f e r e n c e o f t h e f o r -
Hodge
and Binet 7 have demonstrated
A. Yildizhan etal.: Intradural Disc Herniations
amen magnum and to the posterior surfaces of the bodies of the second and third cervical vertebrae; it is also connected by fibrous slips to the posterior longitudinal ligament of the vertebrae, especially near the lower end of the vertebral canal 2' 12, 17,18. These connections have been suggested as a cause for intradural disc herniation, in some cases subsequent to operations l3,14,16. We found loose connections between the dura and the posterior longitudinal ligament in most cases, but in some cases there were separable or nonseparable connections in the lower lumbar, lower thoracic, and lower cervical regions, most frequently at the L 4-L 5, L 3-L 4, L 5-S 1, C 5-C 6, and C 6-C 7 interspaces. Smith t5 reported that 41 per cent of intradural disc ruptures were found at L 4-L 5, 26 per cent at L 3 - L 4 , 13 per cent at L 2 - L 3 , 10 per cent at L I - L 2, 3 per cent at L 5-S 1, and a total of 7 per cent at T 9 - T 10, T 10-T 11 and C 5-C6 levels, the lower thoracic and lumbar spinal canal studies of Blikra 1 and our own findings suggest that the ventral dura at some levels may be firmly adherent to the posterior longitudinal ligament. In such a situation the nucleus pulposus can pass through the annulus fibrosus, posterior longitudinal ligament and the dura mater as if they were one structure. In other cases, dense adhesions and loose connections were observed in some levels and these could be separated bluntly. These adhesions probably are not sufficiently strong to resist a disc herniation without giving way before perforation of the dura. This concept has also been pointed out by Blikra 1. It is interesting that the findings of our abortionnewborn group were parallel to the adult group. These findings suggest that the adhesions are congenital. In the abortion-newborn group ventral and dorsal dural thickness was equal in almost all cases at all levels but in the adult cadavers dorsal dura was thicker in the lumbar and lower cervical interspaces. Penning and Wilmink 1~ showed in their flexion-extension myelographic study that the dural sac was strained to various degrees at different levels. The most extreme strain occurs at the L 4 and L 5 levels which can lead to weakening of the dura at the levels in question in the tbllowing years. Finally, firm epidural adhesions fix the dura to the posterior longitudinal ligament and the disc material perforates the weak and eroded dura mater in the de-
165
termined interspaces. The adhesions between the ventral dura and the posterior longitudinal ligament may already be formed congenitally.
References I. Blikra G (1969) Intradural herniated lumbar disc. J Neurosurg 31:676-679 2. Bloom W, Fawcett DW (1975) A textbook of histology. WB Saunders, Philadelphia, pp 375-376 3. Carcavilla LI, Perun JG, A1-Kudsi ER (1982) Hernie discale lombaire intradurale. Rapport de deux cas. Neurochirurgie 28: 421-424 4. Dandy WE (1942) Serious complications of ruptured intervertebral discs. JAMA 119:474-475 5. Diirig M, Zdrojewski B (1977) Intradurale Sequestration einer cervikalen Diskushernie: ein kasuistischer Beitrag. Arch Orthop Unfallchir 87:151-157 6. Fisher RG (1965) Protrusions of thoracic disc. The factor of herniation through the dura mater. J Neurosurg 22:591-593 7. Hodge CJ, Binet EF, Kieffer SA (1978) Intradural herniation of lumbar intervertebral disc. Spine 3:346-350 8. Lee ST, Fairholm D (1983) Intradural rupture of lumbar intervertebral disc. Can J Neurol Sci 10:192-194 9. Lyons AE, Wise BL (1961) Subarachnoid rupture of intervertebral disc fragments. J Neurosurg 18:242-244 10. Penning L, Wilmink JT (1981) Biomechanics of lumbosacral dural sac. A study of flexion - extension myelography. Spine 4: 398-408 11. Peyser E, I-Iarari A (1977) Intradural rupture of lumbar intervertebral disc: report of two cases with review of the literalure. Surg Neurol 8:95-98 12. Rhodin JAG (1974) Histology. A text and atlas. Oxford University Press, New York London Toronto, pp 322-326 13. Roda JM, Gonzalez C, Balazquez MG, etal (1982) Intradural herniated cervical disc. J Neurosurg 57:278-280 14. Slater RA, Pineda A, Porter RW (1965) Intradural herniation of lumbar intervertebraI discs. Arch Surg 90:266-269 15. Smith RV (1981) Intradural disc rupture. J Neurosurg 55: 117-120 16. Teng P, Papathedodorou C (1964) Intrathecal dislocation of lumbar intervertebral disc. Neurochirurgia 7:57-63 17. Truex RC, Carpenter MB (1969) Neuroanatomy. The Williams and Wilkins, Baltimore, pp 12-21 18. Williams PL, Warwick R (1980) Gray's anatomy. Churchill Livingstone, Edinburgh London Melbourne New York, pp 1045-1052 19. Wilson PJE (1962) Cauda equina compression due to intrathecal herniation of an intervertebral disc. Br J Surg 49:423-428 Correspondence and Reprints: Ahmet Yildizhan, M.D., Department of Neurosurgery, Vakif Gureba Hospital, Sehremini-Istanbul, Turkey.
Acta Neurochir (Wien) (1991) 110:160-165
9 Springer-Verlag 1991 Printed in Austria
Intradural Disc Herniations Pathogenesis, Clinical Picture, Diagnosis and Treatment A. Yildizhan 1, A. Pa~ao~lu 2, T. Okten 3, N. Ekinci 4, K. Aycan 4, and O. Aral 1 ~Department of Neurosurgery, Vakif Gureba Hospital, Istanbul, and Departments of 2Neurosurgery, 3Pathology, and 4Anatomy, Erciyes University, School of Medicine, Kayseri, Turkey
Summary The relatively rare occurrence and uncertainty about pathogenesis of intradurally displaced disc herniations stimulated an anatomico-pathological study into intradural disc herniations. The relation between the ventral dura and posterior longitudinal ligament in the cervical, thoracic, lumbar and sacral regions were examined macroscopically and microscopically,and ventrai and dorsal dural thickness was compared in 20 adult autopsies on patients who died from various causes; in addition, 20 late abortions and newborn cadavers were investigated in the same way. In this study, a total of 40 autopsies has shown that the ventral dura is most frequently and firmly attached to the posterior longitudinal ligament at the L 4-L 5 level and these adhesions may be congenital. In the adult cadavers dorsal dura was found to be thicker than the ventral dura in the lumbar and lower cervical interspaces. Three personal clinical cases of intradurally herniated disc prolapse are shortly described and the diagnosis and management of this pathology discussed.
Keywords:Intervertebral disc displacement; intradural disc herniation; intradural disc rupture; lumbar disc; herniated nucleus pulposus.
Introduction As a very rare pathology, the first report o f a n i n t r a d u r a l h e r n i a t i o n of a n intervertebral disc was presented by W a l t e r E. D a n d y 4 in 1942. D a n d y , in his article related the characteristics of the history a n d neurological findings of this clinical p h e n o m e n o n . I n 1981 Smith Is reported two cases a n d also specified the p u b l i c a t i o n of 43 cases in the literature. The cases have usually been seen at L 4 - 5 a n d L 3-4, b u t they have also been reported unusually at other levels 3, 5, 6, 8,1 ~, 13,16 T h e i n t r a d u r a l finding o f i n t e r v e r t e b r a l disc m a t e r i a l is a rare occurrence. O n l y if the nucleus p u l p o s u s ruptures the a n n u l u s fibrosus, the posterior l o n g i t u d i n a l
ligament, a n d the d u r a mater, can a free f r a g m e n t of disc material migrate into the s u b a r a c h n o i d space. But the m e c h a n i s m of this event a n d the frequent preference o f L 4 - L 5 interspace were n o t well u n d e r s t o o d . These questions a n d three patients with i n t r a d u r a l disc hern i a t i o n treated in our clinics provided the stimulus for a n a n a t o m i c o - p a t h o l o g i c a l investigation of the relation between the spinal dura, posterior l o n g i t u d i n a l ligam e n t a n d d u r a l thickness at all levels t h r o u g h o u t the spinal canal.
Materials and Methods Forty consecutive autopsies were performed during the years 1986 to 1989 in the Neurosurgical, Pathology and Anatomy Departments of Erciyes University Medical School. There were 20 adult cadavers with no history of low back pain or sciatica, and 20 late abortions and newborn cadavers totalling 40 autopsies. In the prone position the spinous processes, the laminae, the articular facets and the pedicles were removed. First, a transverse cross section was made at every level of both the posterior longitudinal ligament and the annulus fibrosus from cervical to sacral regions for obtaining pathological specimensand then the dura was opened longitudinally and the spinal cord removed after section of the roots. Finally the dura was cut away except for the anterior wall which then could be lifted off from the posterior longitudinal ligament at the same levels. Loose or firm connections or dense adhesions between the dura, the ligament, and the annulus were noted at every level. Following macroscopical evaluation, sequential sections were made and stained with haematoxylin and eosin (HE). The relation between the ventral dura and the posterior longitudinal ligament were examined, and ventral and dorsal thickness was compared microscopically.
Results Only loose c o n n e c t i o n s were f o u n d between the d u r a a n d the ligament at m o s t levels. But at 43 levels there
A. Yildizhan etal.: Intradural Disc Herniations
161
Table 1. Incidence and Location of Separable and Nonseparable Adhesions Between Ventral Dura and Posterior Longitudinal Ligament in 40 Autopsies
Levels
c2-c3 C3-C4 C4-C5 C5-C6 C6-C7 C 7-T 1 T l-T2 T2-T3 T3-T4 T4-T5 TS-T6 T6T7 TT-T8 TS-T9 T 9-T 10 T10-Tll T 11-T 12 T 12-L 1 LI-L2 L2-L3 L3-L4 L4-L 5 L 5-S 1
Adult cadavers
Abortion and newborn cadavers
No connec,
Loose connec,
1 3 1 1 2 3 5 4 6 6 5 4 1 1 1 2 1 1 2 -
16 18 16 13 12 16 15 15 16 13 13 15 15 16 17 17 16 16 16 13 5 1 5
Dense adhes, 3 1 1 4 4 1 1 1 1 1 2 1 1 1 2 2 3 11 12 12
Firm connec,
No connec,
Loose connec,
Dense adhes,
Firm connec.
1 2 3 1 1 1 1 1 1 1 1 2 4 7 3
2 4 1 1 2 4 4 4 8 7 4 2 1 2 2 3 2 2 1 -
17 17 15 16 15 16 16 16 16 12 12 16 18 18 16 17 16 17 15 15 14 10 15
2 1 1 2 3 1 1 1 1 1 1 1 2 3 4 7 4
l 1 1 1 1 1 1 2 3 1
w e r e v e r y f i r m c o n n e c t i o n s b e t w e e n t h e d u r a , t h e lig-
ble 1) a n d less f r e q u e n t l y a t t h e L 3 - L 4 , L 5 - S 1 levels,
a m e n t , a n d t h e a n n u l u s ( T a b l e 1). T h e s e i n t i m a t e c o n -
a n d i n t h e l o w e r c e r v i c a l i n t e r s p a c e s ( F i g . 1 C).
nections could not be divided by blunt dissection. Non-
Among
20 a d u l t s a n d 20 o t h e r s , f i r m c o n n e c t i o n s
separable connections of this kind were found at the
that could not be separated bluntly were found in a
L 4 - L 5 i n t e r s p a c e i n 7 a d u l t s a n d 3 n e w b o r n s . I n sev-
t o t a l o f 10 c a s e s a t t h e L 4 - L 5 level a n d less f r e q u e n t l y
eral other cases dense adhesions were observed in the
a t s o m e o t h e r levels (Figs. 1 D a n d 2).
lower lumbar, occasionally lower thoracic, and some-
Ventral and dorsal dural thickness were investigated
times lower cervical interspaces; but these could be
microscopically and the comparable results were sum-
separated bluntly. The findings are summarized in Ta-
m a r i z e d in T a b l e 2. S o m e p h o t o g r a p h s
b l e 1.
obtained during microscopical study are also presented
T h e r o u t i n e h i s t o l o g i c a l s e c t i o n s o f v a r i o u s levels
which were
( F i g s . 3 a n d 4).
o b t a i n e d a t a u t o p s y w e r e r e - e x a m i n e d a n d s i m i l a r results were observed in the microscopical study. The ventral dura was not connected to the posterior long i t u d i n a l l i g a m e n t a t 106 levels i n t o t a l b e t w e e n t h e C 3 - C 4 a n d t h e L 2 - L 3 i n t e r s p a c e s (Fig. 1 A ) . T h e r e w e r e l o o s e c o n n e c t i o n s i n a t o t a l o f 670 levels between the ventral dura and the posterior longitudinal ligament in the cervical, thoracic, and lumbar regions ( F i g s . 1 B a n d 4). Dense adhesions which could be separated bluntly w e r e o b s e r v e d m o s t f r e q u e n t l y a t t h e L 4 - L 5 level ( T a -
Case Reports Case 1. A 57-year-old housewife had experienced moderate episodes of low back pain for approximately two years. Three days before hospitalization very severe pains and numbness started in her back and both legs after lifting a heavy object and two days later these pains were followed by urinary and faecal incontinence. Neurological examination revealed hypaesthesia and hypalgesia of L 5 bilaterally and all sacral dermatomes and severe weakness of flexor and extensor movements of the feet bilaterally. Achilles tendon reflexes were absent. Iohexol myelography revealed a complete block at L 4-5.
162
A. Yildizhan et al.: Intradural Disc Herniations
Fig. 1. Photomicrographs of a transverse section of the anterior wall of the spinal canal. A) The ventral dura (VD) is not connected to the posterior longitudinal ligament (PLL) at the L 2 - L 3 level. B) Loosely connected VD and P L L at the L 5-S 1 level. C) Dense adhesions between the VD and the P L L at the L 3 - L 4 level. D) The VD and the P L L are firmly connected at the L 4 - L 5 level (HE x 32)
A. Yildizhan etal.: Intradural Disc Herniations
Fig. 2. The ventral dura (VD) and the posterior longitudinal ligament (PLL) are intimately connected at the C 6-C 7 level (HE x 32)
163
Fig. 3. Three photomicrographs form a complete photograph. The dorsal dura (DD) is thicker than the ventral dura (VD) at the C 5-C 6 interspace (HE x 32)
A total laminectomy was performed at L 4 and a half at L5. This revealed that the dura was anteriorly adherent by scar tissue to the posterior longitudinal ligament and that the disc material was extruding into the dural sac. When the dura was opened posteriorly an irregular mass of disc was seen in the dural sac compressing the nerve roots. After removal of the disc, a rent approximately 1 x 0.7cm communicating with the L4-5 interspace was found in the ventral wall of the dura. This could not be closed. The patient made an uneventful recovery. One day after operation radicular pain had resolved and within two months she had regained normal sensation and strength. Her bladder and bowel functions were normal in the following fifth months. Case 2. A 70-year-old man was complaining for 11 months of fluctuating low back pain. Four days before hospitalization, he suffered from acute lumbar and radicular pain on both sides but more severe on the right side. He had paraparesis and urinary and faecal retention. Pantopaque myelography showed a block round in shape across the L 1-2 level. We performed an exploratory laminectomy at L 1-2 and intradural disc material was removed. We noticed epidural scar tissue at L 1-2. The dura was firmly adherent both to the underlying disc mass anteriorly and to the longitudinal ligament Fig. 4. Two photomicrographs make a complete photograph. The dorsal dura (DD) is thicker than the ventral dura (VD), and the VD and the posterior longitudinal ligament (PLL) are loosely connected at the L 5-S 1 level (HE x 32)
A. Yildizhan etal.: Intradural Disc Herniations
164 Table 2. Proportional Results of Ventral and Dorsal Dural Thickness in Each Interspace
Levels
Ventral dural thickness proportional to dorsal dural thickness Adult cadavers
C2-C3 C 3-C 4 C4-C 5 C 5-C 6 C6-C7 C7-T 1 T 1-T 2 T 2-T 3 T 3-T 4 T4-T 5 T5-T6 T 6-T 7 T 7-T 8 T 8-T 9 T 9-T 10 T 10-T 11 T 11-T 12 T 12-L 1 L1-L2 L2-L3 L3-L4 L4-L 5 L5-S 1
Abortion and newborn cadavers
More
Equal
Less
More
Equal
Less
1 1 1
18 20 18 17 17 18 20 20 20 19 20 20 20 20 20 20 20 19 18 17 16 15 15
1 2 3 3 2 1 2 3 4 5 4
1 1 1 -
19 20 20 20 19 20 20 20 20 20 19 20 20 20 20 20 20 20 20 20 20 20 19
1 1
posteriorly. The patient recovered slowly until he could walk unaided within 4 months. Bowel function was normal after 4 months, and bladder function within 8 months after the operation. Case 3. The history of this 53-year-old man was very similar to that of case 2. However his neurological dysfunction was not so severe. He had right leg weakness and atrophy, right radicular pain and L4 hypalgesia. He had no sphincter disturbance. Pantopaque myelography showed an incomplete block at the L 3M interspace. An exploratory laminectomy was permormed and we noticed an intradural disc rupture. Epidural scar tissue was less prominent compared to case 2. After the operation, the patient recovered excellently. The radicular pain resolved, and sensory deficiency and leg weakness improved within 6 weeks.
e r i z e d t o m o g r a p h y . E x i s t e n c e o f m a c r o p h a g e s in t h e c e r e b r o s p i n a l fluid o b t a i n e d at m y e l o g r a p h y m a y also s u g g e s t t h e d i a g n o s i s a t t h e p r e - o p e r a t i v e s t a g e 15. T h e m o s t c o m m o n m y e l o g r a p h i c f i n d i n g is t o t a l b l o c k t o t h e f l o w o f t h e c o n t r a s t m e d i u m 7' 11,15. T h e p r e s e n c e o f a n i r r e g u l a r l y d e l i n e a t e d filling d e f e c t o r t h e a p p e a r a n c e o f a c i r c u m s c r i b e d m a s s a t t h e level o f t h e d i s c s p a c e at myelography should suggest an intradural disc rupture. R a d i c u l a r pain a n d neurological deficit are charct e r i s t i c a l l y s e v e r e , b u t t h i s p h e n o m e n o n a t L 1 a n d bel o w c a r r i e s a g o o d p r o g n o s i s 9'15' 19. I n t h e s e c a s e s t h e f u n c t i o n a l r e c o v e r y is s o m e w h a t s l o w b u t e x c e l l e n t a s a rule. I f t h e p a t i e n t h a s b l a d d e r a n d b o w e l c o m p l a i n t s ,
Discussion
p r o m p t s u r g e r y is i m p o r t a n t . A n o p e r a t i n g m i c r o s c o p e
A l t h o u g h n e a r l y 50 y e a r s h a v e p a s s e d s i n c e p u b l i c a t i o n o f t h e t w o c a s e s b y D a n d y 4, n o m a j o r n e w as-
is i n v a l u a b l e d u r i n g s u r g e r y , p a r t i c u l a r l y w h e n r e m o v i n g t h e d i s c m a s s a t t h e c o n u s level.
pects regarding aetiology, incidence, characteristics of
I t is n o t e a s y t o e x p l a i n h o w n u c l e u s p u l p o s u s p e r -
the history, neurological findings, and postoperative
f o r a t e s t h e d u r a m a t e r a n d w h y t h i s p h e n o m e n o n oc-
course of the lumbar intradural disc ruptures have been
c u r s m o s t f r e q u e n t l y a t t h e L 4 - L 5 level 9' 15. Some histology and anatomy textbooks state that
d e s c r i b e d in s u b s e q u e n t p u b l i c a t i o n s . that intra-
the narrow epidural space contains loose connective
dural disc rupture can be diagnosed pre-operatively by
and fatty tissue and venous plexus, and that the spinal
utilizing metrizamide enhancement of spinal comput-
d u r a m a t e r is a t t a c h e d o t t h e c i r c u m f e r e n c e o f t h e f o r -
Hodge
and Binet 7 have demonstrated
A. Yildizhan etal.: Intradural Disc Herniations
amen magnum and to the posterior surfaces of the bodies of the second and third cervical vertebrae; it is also connected by fibrous slips to the posterior longitudinal ligament of the vertebrae, especially near the lower end of the vertebral canal 2' 12, 17,18. These connections have been suggested as a cause for intradural disc herniation, in some cases subsequent to operations l3,14,16. We found loose connections between the dura and the posterior longitudinal ligament in most cases, but in some cases there were separable or nonseparable connections in the lower lumbar, lower thoracic, and lower cervical regions, most frequently at the L 4-L 5, L 3-L 4, L 5-S 1, C 5-C 6, and C 6-C 7 interspaces. Smith t5 reported that 41 per cent of intradural disc ruptures were found at L 4-L 5, 26 per cent at L 3 - L 4 , 13 per cent at L 2 - L 3 , 10 per cent at L I - L 2, 3 per cent at L 5-S 1, and a total of 7 per cent at T 9 - T 10, T 10-T 11 and C 5-C6 levels, the lower thoracic and lumbar spinal canal studies of Blikra 1 and our own findings suggest that the ventral dura at some levels may be firmly adherent to the posterior longitudinal ligament. In such a situation the nucleus pulposus can pass through the annulus fibrosus, posterior longitudinal ligament and the dura mater as if they were one structure. In other cases, dense adhesions and loose connections were observed in some levels and these could be separated bluntly. These adhesions probably are not sufficiently strong to resist a disc herniation without giving way before perforation of the dura. This concept has also been pointed out by Blikra 1. It is interesting that the findings of our abortionnewborn group were parallel to the adult group. These findings suggest that the adhesions are congenital. In the abortion-newborn group ventral and dorsal dural thickness was equal in almost all cases at all levels but in the adult cadavers dorsal dura was thicker in the lumbar and lower cervical interspaces. Penning and Wilmink 1~ showed in their flexion-extension myelographic study that the dural sac was strained to various degrees at different levels. The most extreme strain occurs at the L 4 and L 5 levels which can lead to weakening of the dura at the levels in question in the tbllowing years. Finally, firm epidural adhesions fix the dura to the posterior longitudinal ligament and the disc material perforates the weak and eroded dura mater in the de-
165
termined interspaces. The adhesions between the ventral dura and the posterior longitudinal ligament may already be formed congenitally.
References I. Blikra G (1969) Intradural herniated lumbar disc. J Neurosurg 31:676-679 2. Bloom W, Fawcett DW (1975) A textbook of histology. WB Saunders, Philadelphia, pp 375-376 3. Carcavilla LI, Perun JG, A1-Kudsi ER (1982) Hernie discale lombaire intradurale. Rapport de deux cas. Neurochirurgie 28: 421-424 4. Dandy WE (1942) Serious complications of ruptured intervertebral discs. JAMA 119:474-475 5. Diirig M, Zdrojewski B (1977) Intradurale Sequestration einer cervikalen Diskushernie: ein kasuistischer Beitrag. Arch Orthop Unfallchir 87:151-157 6. Fisher RG (1965) Protrusions of thoracic disc. The factor of herniation through the dura mater. J Neurosurg 22:591-593 7. Hodge CJ, Binet EF, Kieffer SA (1978) Intradural herniation of lumbar intervertebral disc. Spine 3:346-350 8. Lee ST, Fairholm D (1983) Intradural rupture of lumbar intervertebral disc. Can J Neurol Sci 10:192-194 9. Lyons AE, Wise BL (1961) Subarachnoid rupture of intervertebral disc fragments. J Neurosurg 18:242-244 10. Penning L, Wilmink JT (1981) Biomechanics of lumbosacral dural sac. A study of flexion - extension myelography. Spine 4: 398-408 11. Peyser E, I-Iarari A (1977) Intradural rupture of lumbar intervertebral disc: report of two cases with review of the literalure. Surg Neurol 8:95-98 12. Rhodin JAG (1974) Histology. A text and atlas. Oxford University Press, New York London Toronto, pp 322-326 13. Roda JM, Gonzalez C, Balazquez MG, etal (1982) Intradural herniated cervical disc. J Neurosurg 57:278-280 14. Slater RA, Pineda A, Porter RW (1965) Intradural herniation of lumbar intervertebraI discs. Arch Surg 90:266-269 15. Smith RV (1981) Intradural disc rupture. J Neurosurg 55: 117-120 16. Teng P, Papathedodorou C (1964) Intrathecal dislocation of lumbar intervertebral disc. Neurochirurgia 7:57-63 17. Truex RC, Carpenter MB (1969) Neuroanatomy. The Williams and Wilkins, Baltimore, pp 12-21 18. Williams PL, Warwick R (1980) Gray's anatomy. Churchill Livingstone, Edinburgh London Melbourne New York, pp 1045-1052 19. Wilson PJE (1962) Cauda equina compression due to intrathecal herniation of an intervertebral disc. Br J Surg 49:423-428 Correspondence and Reprints: Ahmet Yildizhan, M.D., Department of Neurosurgery, Vakif Gureba Hospital, Sehremini-Istanbul, Turkey.
