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Idiopathic spinal cord herniation
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Idiopathic spinal cord herniation Andrew P. Morokoff1 MBBS, Brian M. Tress2 MD FRACR, Andrew H. Kaye3 MD FRACS Departments of 1,3Neurosurgery, 3Surgery and 2Radiology, Royal Melbourne Hospital, University of Melbourne, Parkville, VIC 3050, Australia
Summary Spinal cord herniation is a rare condition that has become increasingly recognised in the last few years. The authors report a case of idiopathic spinal cord herniation in a 33 year old woman who presented with progressive Brown-Sequard syndrome. The diagnosis was made on MR imaging. After repairing the herniation the patient made a gradual improvement. Potential causes are discussed, including the possible role of dural tethering. In conclusion, idiopathic spinal cord herniation is a potentially treatable condition that should be more readily diagnosed with increased awareness and newer imaging techniques such as high resolution MRI. © 2001 Harcourt Publishers Ltd Journal of Clinical Neuroscience (2001) 8(2), 180–183 © 2001 Harcourt Publishers Ltd DOI: 10.1054/jocn.2000.0819, available online at http://www.idealibrary.com on
Keywords: spinal cord, idiopathic, herniation Received 9 March 2000 Accepted 21 March 2000 Correspondence to: Dr Andrew Morokoff, Department of Neurosurgery, Royal Melbourne Hospital, Parkville 3050, Victoria, Australia. Tel.: 61 3 9342 7000; Fax: 61 3 9347 8332.
INTRODUCTION Idiopathic spinal cord herniation (ISCH) is a rare clinical entity which almost always occurs in the anterior or antero-lateral thoracic spine in middle aged patients. It usually presents with slowly progressive Brown-Sequard syndrome or paraplegia over years and there is often a delay in diagnosis. Some cases may be related to trauma but spontaneous instances remain idiopathic. Since the first case report by Wortzman in 1974 there have been 30 further cases reported in the literature. We describe a case of ISCH with the associated imaging and surgical findings and review the literature. CASE REPORT A 33 year old, previously well, woman presented with an 8-year history of numbness on the right side of her body which began in the right lower limb and progressed upwards. There was no history of birth, childhood or spinal trauma. Over the last 2 years she had also developed a left foot weakness with increasing ‘dragging’ of the left leg and slowness of her gait, particularly when she was tired. There was no sphincter disturbance and no pain. Clinical examination revealed a spastic gait with markedly increased tone in the left lower limb, clonus at the ankle and mild weakness of hip flexion and ankle dorsi-flexion. There was hyperreflexia in both lower limbs, particularly on the left. The plantar response was down-going bilaterally. There was reduced sensation to pin-prick and temperature on the right up to the T8 level and joint position sense was reduced in both lower limbs, but more noticeably on the left. The cranial nerves and upper limbs were normal. Overall, there was a Brown-Sequard syndrome indicating a predominantly left-sided cord lesion at the T8 level. Journal of Clinical Neuroscience (2001) 8(2)
Fig. 1 T2-weighted axial MRI through T8 showing high signal CSF anterior to ventral dura indicating extradural arachnoid diverticulum.
The patient had been previously extensively investigated over the preceeding 7 years with computed tomography (CT) myelography, magnetic resonance imaging (MRI) and lumbar puncture, with no cause being found for her symptoms. More recent, higher resolution MR imaging revealed evidence of thoracic spinal cord herniation at the T8 level. On the T2 image there was a crescentic band of high signal indicating CSF between the anterior dura and the posterior margin of the thoracic vertebra (Fig. 1). The cord was closely applied to the ventral dura on the sagittal slices with apparent widening of the dorsal subarachnoid space; however there was no evidence of an arachnoid cyst and normal flow artefacts could be seen dorsal to the cord (Fig. 2). At one point, the spinal cord could be seen herniating through the left ventrolateral aspect of the dura, suggesting the diagnosis (Fig. 3). At this region the cord looked, thinner, distorted and rotated. Surgery involved a T7–9 laminectomy; the dura was opened longitudinally in the midline and CSF was expressed under considerable pressure. Multiple arachnoid adhesions were divided but there was no dorsal arachnoid cyst. The cord was gently retracted back and inspection of its left side revealed a dural defect of approximately 525 mm through which pale, yellowish, swollen cord tissue was herniating into an extradural space (Fig. 4). It was unclear whether this space represented a dural diverticulum or arachnoid meningocoele, although there was CSF epidurally. The dural defect was opened around the herniated cord. There was a significant rostral extent of the herniated segment, suggesting perhaps a tethering process by the superior edge of the dural defect. It was considered whether to place a dural graft, but the herniated cord segment caused marked distortion of the normal cord when fully reduced. By day 3 postoperatively the patient noted some improvement in the sensation on her right side and she was discharged home after 9 days. She continued to make slow improvement over the next 3 months.
DISCUSSION This case of ISCH is similar to the previously reported clinical patterns (Table 1). In the 30 cases, the age range was 23 to 71, with a mean of 49. There was a female predominance of 1.8 : 1. All cases occured in the thoracic spine from T2 to T10, and all were © 2001 Harcourt Publishers Ltd
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Fig. 3 T2-weighted axial MRI showing spinal cord herniation in left ventrolateral position.
Fig. 4 Diagrammatic representation of appearance of spinal cord segment herniating through oval-shaped dural defect.
Fig. 2 T2-weighted sagittal MRI showing thoracic cord at T8 level ventrally displaced but with normal CSF flow voids dorsally.
ventral or ventrolateral directed herniations, with a slight left-sided predominance. The clinical presentation is striking for its chronicity and gradual progression of neurological symptoms, often starting with sensory disturbance then involving the pyramidal tracts and occasionally the sphincters as well. Only 4 out of the 30 cases (13%) presented with something other than Brown-Sequard syndrome, namely paraparesis in 31–3 and monoparesis in 1.4 Sphincter disturbance was relatively common, occurring in 20%. Spinal pain was a very uncommon feature. Posture related symptoms occurred occasionally. MRI was the key to diagnosing the condition in this patient and has formed the basis for diagnosis in all the other recent cases. CT myelography has also been found to be helpful. The features seen are a ventrally displaced, often thinned cord in the upper or midthoracic region which may look distorted or rotated. The herniation itself may be visible, as in this case, as a short segment of cord situated anterior to the ventrolateral dura. The segment may be quite short in the rostral-caudal direction and non-fine-cut axial scans may miss it, which probably explained why it was missed in our patient’s original MRI. A dorsal intradural arachnoid cyst is rarely visible on imaging, even if present at operation, and © 2001 Harcourt Publishers Ltd
normal CSF pulsation artefacts or phase contrast studies1 are helpful in showing it to be absent. Myelography may show slowfilling around the herniation but again rarely shows a filling defect related to an arachnoid cyst, even if present, because many are arachnoid diverticula rather than totally encapsulated cysts. Endoscopy may be a useful adjunct as used by Miyake et al.5 preoperatively to inspect the dorsal subarachnoid space and confirm the diagnosis, and again intraoperatively to show the cord herniating into an epidural arachnoid cyst, rather than a dural diverticulum. Spinal cord herniation per se may be traumatic, iatrogenic (post spinal surgery) or idiopathic. Post surgical cases have occurred in the dorsal cervical spine some months or years after cervical laminectomy, during which a dural tear has gone unrecognised. A number of traumatic cases have been reported involving the thoracolumbar spine, which interestingly tended to present with patterns other than Brown-Sequard syndrome such as para- or monoparesis; these are uncommon in the idiopathic variety. Three idiopathic cases noted above did have a history of trauma many years prior to the episode of herniation but it was not clear if these were related to the SCH.6–8 No identifiable relationship to trauma was found at surgery, e.g. shrapnel in the third case of Borges,6 but subclinical trauma remains an etiologic possibility. There are a number of theories regarding the cause of idiopathic herniations, which can broadly be classified as congenital, Journal of Clinical Neuroscience (2001) 8(2)
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Thirty-one cases of idiopathic spinal cord herniation
Year
Series
Age/sex
1974
Wortzman20
63 M
1981
Masuzawa7
36 M
1990 1991
Ohe13 Tronnier15
61 M 45 F
1991
Isu5
43 F 45 F
1993
Nazakawa12
43 F 39 F
1994
White19
61 F 39 M
1995 1995
Batzdorf1 (comment) Borges1
23 F 68 F 68 M 48 F
1995
Kumar 6
38 M
1996
Hausman4
57 F
36 M 1996
Matsumara8
63 F
1996
Miura10
49 M
1996
Sioutos14
34 F
1996
Urbach16
44 M
1997
Henry4
30 F
1997
Uchino17
71 F
1998
Miyake11
45 F 53 M
1998
Marshman9
55 F
1998
Dix3
44 F
1998
Brugieres2
54 F
1998
Watters18
70 M 55 F
1999
Current study
33 F
Clinical symptoms Brown-Sequard Left T9 Brown-Sequard Left T6 Spastic paraparesis Brown-Sequard Right T5 Brown-Sequard Right T5 Brown-Sequard Left T4 Brown-Sequard Right T3 Brown-Sequard Left T7 Brown-Sequard Right T6 Brown-Sequard Left T10 Brown-Sequard Right T6 Brown-Sequard Right T9 Brown-Sequard Left T4 Brown-Sequard Left T10 Brown-Sequard Left T8 Brown-Sequard Left T10 Brown-Sequard Left T7 Brown-Sequard Left T4 spastic right leg, sphincter dist. spastic paraparesis level T6/7 Brown-Sequard Left T6 (sens only) Brown-Sequard Right T6–T8 Brown-Sequard Left T4 Brown-Sequard Right T6 Brown-Sequard Left T6 Brown-Sequard Left T7–T8 Brown-Sequard Left T7–T8 Brown-Sequard Right T6 Paraparesis T7–T8 Brown-Sequard Left T3–T4 Brown-Sequard Left T8
D
AC
Side & level
36
No
Left T7
Thoracotomy
motor and sphincters
12
No
T4
TLY
motor and sensation
120 48
Yes No
T4–T5 T3–T4
TLY TLY
no change sensation
12
Yes
T5–T6
TLY
motor and sensation
20
Yes
T2–T3
TLY
sensation
60
No
T2–T3
TLY
motor and sensation
36
T4
TLY
motor
12
Right T4–T5
TLY
no change
Improvement
18
No
T8
TLY
no change
24
No
T6
motor at 2nd proc
108
No
T7
TLY, thor 2nd proc thoracotomy
motor and sensory
96
No
T3
TLY
motor
120
No
T7–T8
TLY
motor
24
No
T7–T8
TLY
96
No
T6–T7
84
No
T6–T7
costotransversectomy and discectomy TLY
216
Yes
T3–T4
TLY
motor and sensation worse motor and sensation
13
Yes
T5–T6
laminectomy;U/S
motor and sphincter
24
No
T6–T7
TLY
motor and sphincter
24
No
T5–T6
TLY
motor and sphincter
24
Yes
T7
TLY
24
Yes
T4–T4
motor and sensory, moderate sphincter no change
48
No
T3–T4
motor and sensation
72
No
T2–T3
endoscopy, laminoplasty laminoplasty
motor
168
No
T7–T8
laminectomy
motor and sphincter
–0
No
T7–T8
motor
60
No
T6
6 120
No No
T5–T6 midline T3–T4
laminectomy intraop U/S laminectomy resection laminectomy laminectomy2
worse motor and proprioception sensation motor and sensation
96
No
T7–T8
laminectomy
sensation
acquired or a combination. An early postulate was herniation into a duplicated dura, or dural diverticulum,6,9,10 but this has not been confirmed in many subsequent reports. Wortzman11 proposed dural injury from a ruptured thoracic disc. Miura4 noted the association with other congenital defects such as abnormal laminae, suggesting a midline fusion disorder. Probably the most dominant theory5,6,12,13 emphasises the naturally ventral position of the thoracic cord (ISCH does not occur in the cervical or lumbar Journal of Clinical Neuroscience (2001) 8(2)
Procedure
gait
region) and suggests that it may become adherent to a dural defect and then be pushed through with abnormal movements, or CSF pulsations during the cardiorespiratory cycle. The cord may be ‘sucked’ out by negative pressure in the epidural space,5 or pushed out by dorsal pressure, possibly from an arachnoid cyst.14 Uchino15 suggests, however, that the cyst may be a secondary effect from arachnoidal distortions and adhesions caused by the abnormal ventral position of the cord. The dural defect may be congenital or, © 2001 Harcourt Publishers Ltd
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Actinomyces brain abscesses 183
less likely, acquired secondary to pressure from the cord or abnormal movement of the cord. Watters16 has noted the presence of a nerve root exiting through the dural defect, suggesting a cord malformation. The clinical symptoms may be related to tethering of the cord by the margin of the dural defect. Borges6 reported a case similar to ours, where there was a significant amount of rostral cord distortion epidurally, again suggesting tethering or traction on the cord. This may be exacerbated by arachnoidal adhesions, posteriorly and around the herniation.2,4,9,13 Vascular compromise may also be a contributing factor.9,17 There is consensus regarding the presence of functional neural tissue in the herniated segment which in most cases, as in ours, appears as an abnormal, exophytic gliotic mass. Two reports describe partial resection of the herniated mass (Brugieres1 and Kumar12). The histopathological findings included hypertrophied astrocytes, pilocytic gliosis and Rosenthal fibres with normal or dilated axons. Chronic reactive change was noted.1 In the first case the patient suffered an initial deterioration followed by progressive improvement; in the second there was no postoperative deterioration. Borges6 agrees that functioning axons may be present, therefore the herniated mass should be replaced intradurally and preserved. Most authors then recommend closing the dural defect, with a dorsal patch graft if necessary. We found that this was impossible without causing excess compression of the spinal cord within the dural space. Reduction of the tethering effect of the herniation on the spinal cord may be a more important surgical goal than complete restoration of dural and cord anatomy.
CONCLUSION Idiopathic spinal cord herniation is a rare condition which affects the ventrolateral thoracic spinal cord. The pathogenesis is unclear but is probably related to pressure from the ventrally situated thoracic cord, leading to an acquired, or exacerbating a congenital, dural defect. It most commonly presents with progressive BrownSequard syndrome of months to years duration and can be diagnosed successfully with MRI. Operative decompression of the herniation usually leads to clinical improvement. REFERENCES 1.
2.
3. 4. 5. 6.
7. 8. 9. 10.
11.
Brugieres P, Malapert D, Adle-Biassette H, Fuerxer F, Djindjian M, Gaston A. Idiopathic spinal cord herniation: value of MR phase-contrast imaging. Am J Neuroradiol 1999; 20: 935–939. Ohe T, Hoshino Y, Kurokawa T. A case of idiopathic herniation of the spinal cord associated with duplicated dura mater and with an arachnoid cyst (in Japanese). Nippon Seikeigeka Gakkai Zasshi 1990; 64: 43–49. Sioutos P, Arbit E, Tsairis P, Gargan R. Spontaneous thoracic spinal cord herniation: a case report. Spine 1996; 21: 1710–1713. Miura Y, Mimatsu K, Matsuyama Y, Yoneda M, Iwata H. Idiopathic spinal cord herniation. Neuroradiology 1996; 38: 155–156. Miyake S, Tamaki N, Nagashima T, Kurata H, Eguchi T, Kimura H. Idiopathic spinal cord herniation. J Neurosurg 1998; 88: 331–335. Borges LF, Zervas NT, Lehrich JR. Idiopathic spinal cord herniation: a treatable cause of the Brown-Sequard syndrome. Neurosurgery 1995; 36: 1028–1033. Tronnier VM, Steinmetz A, Albert FK, Scharf J, Kunze S. Hernia of the spinal cord: a case report and review of the literature. Neurosurgery 1991; 29: 916–919. Urbach H, Kaden B, Pechstein U, Solymosi L. Herniation of the spinal cord 38 years after childhood trauma. Neuroradiology 1996; 38: 157–158. Dix JE, Griffith W, Yates C, Johnson B. Spontaneous thoracic spinal cord herniation through an anterior dural defect. AJNR 1998; 19: 1345–1348. Masuzawa H, Nakayama H, Shitara N, Suzuki T. Spinal cord herniation into a congenital extradural arachnoid cyst causing Brown-Sequard syndrome. J Neurosurg 1981; 55: 983–986. Wortzman G, Tasker RR, Rewcastle NB, Richardson JC, Pearson FG. Spontaneous incarcerated herniation of the spinal cord into a vertebral body: a unique cause of paraplegia – case report. J Neurosurg 1974; 41: 631–635.
© 2001 Harcourt Publishers Ltd
12. 13. 14.
15. 16.
17.
Kumar R, Taha J, Greiner AL. Herniation of the spinal cord: case report. J Neurosurg 1995; 82: 131–136. Nazakawa H, Toyama Y, Satomi K et al. Idiopathic spinal cord herniation: report of two cases and review of the literature. Spine 1993; 18: 2138–2141. Isu T, Iizuka T, Iwasaki Y, Nagashima M, Akino M, Abe H. Spinal cord herniation associated with an intradural spinal arachnoid cyst diagnosed by magnetic resonance imaging. Neurosurgery 1991; 29: 137–139. Uchino A, Kato A, Momazaki N, Yukitake M, Kudo S. Spinal cord herniation: report of two cases and review of the literature. Eur Radiol 1997; 7: 289–292. Watters MR, Stears JC, Osborn AG, Turner GE, Burton BS, Lillehei K, Yuh TC. Transdural spinal cord herniation: imaging and clinical spectra. AJNR 1998; 19: 1337–1344. White BD, Firth JL. Anterior spinal hernia: an increasingly recognised cause of thoracic cord dysfunction. J Neurol Neurosurg Psychiatry 1994; 57: 1433–1435.
Multiple actinomyces brain abscesses: case report Ming-Shih Tsai1,3 MD PHD, Jia-Jiunn Tarn4 MD, Keng-Shing Liu5 MD, You-Li Chou1 PHD, Ching-Liang Shen2 PHD 1
Institute of Biomedical Engineering, 2Department of Anatomy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan, 3Department of Neurosurgery, 4Department of Pathology, 5Department of Medicine, Tainan Hospital, Department of Health, Tainan 700, Taiwan
Summary A case of multiple cerebral abscesses caused by actinomyces is reported in a 37 year old male with mucoepidermoid carcinoma of the right lung. In conjunction with penicillin, sulfonamide and erythromycin, the patient underwent stereotactic surgery for aspiration of the brain abscesses under (CT). The bacteria, considered to originate from the right lung, were identified from the abscess material obtained at surgery. Using proper therapy to control infection and intracranial pressure is important. A long term follow up with frequent computerised tomography evaluation has been conducted and the patient outcome has been successful recovery. © 2001 Harcourt Publishers Journal of Clinical Neuroscience (2001) 8(2), 183–186 © 2001 Harcourt Publishers Ltd DOI: 10.1054/jocn.1999.0744, available online at http://www.idealibrary.com on
Keywords: actinomyces, intracranial pressure, multiple brain abscesses, stereotactic aspiration Received 18 September 1998 Accepted 8 December 1999 Correspondence to: Dr Ming-Shih Tsai, No. 2 Dong Rong Street, Tainan 701, Taiwan. Tel.: 886-6-2371087; Fax: 886-6-234-5955
INTRODUCTION Actinomyces is the most important human pathogen in actinomycetaceae and is closely related to mycobacteria and commensals within the oral cavity and alimentary tract.1 They were thought to be similar to fungi because of branching and the formation of a mycelial network but the presence of muramic acid in cell walls and the absence of a membrane bound nucleus clearly align them with the bacteria. The first report of a brain actinomycotic lesion was by Ponfick in 1882.2 Rare cases of multiple brain abscesses caused by these bacteria and the corresponding treatment leading to successful recovery have been reported in the literature.2–7 Journal of Clinical Neuroscience (2001) 8(2)
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Idiopathic spinal cord herniation Andrew P. Morokoff1 MBBS, Brian M. Tress2 MD FRACR, Andrew H. Kaye3 MD FRACS Departments of 1,3Neurosurgery, 3Surgery and 2Radiology, Royal Melbourne Hospital, University of Melbourne, Parkville, VIC 3050, Australia
Summary Spinal cord herniation is a rare condition that has become increasingly recognised in the last few years. The authors report a case of idiopathic spinal cord herniation in a 33 year old woman who presented with progressive Brown-Sequard syndrome. The diagnosis was made on MR imaging. After repairing the herniation the patient made a gradual improvement. Potential causes are discussed, including the possible role of dural tethering. In conclusion, idiopathic spinal cord herniation is a potentially treatable condition that should be more readily diagnosed with increased awareness and newer imaging techniques such as high resolution MRI. © 2001 Harcourt Publishers Ltd Journal of Clinical Neuroscience (2001) 8(2), 180–183 © 2001 Harcourt Publishers Ltd DOI: 10.1054/jocn.2000.0819, available online at http://www.idealibrary.com on
Keywords: spinal cord, idiopathic, herniation Received 9 March 2000 Accepted 21 March 2000 Correspondence to: Dr Andrew Morokoff, Department of Neurosurgery, Royal Melbourne Hospital, Parkville 3050, Victoria, Australia. Tel.: 61 3 9342 7000; Fax: 61 3 9347 8332.
INTRODUCTION Idiopathic spinal cord herniation (ISCH) is a rare clinical entity which almost always occurs in the anterior or antero-lateral thoracic spine in middle aged patients. It usually presents with slowly progressive Brown-Sequard syndrome or paraplegia over years and there is often a delay in diagnosis. Some cases may be related to trauma but spontaneous instances remain idiopathic. Since the first case report by Wortzman in 1974 there have been 30 further cases reported in the literature. We describe a case of ISCH with the associated imaging and surgical findings and review the literature. CASE REPORT A 33 year old, previously well, woman presented with an 8-year history of numbness on the right side of her body which began in the right lower limb and progressed upwards. There was no history of birth, childhood or spinal trauma. Over the last 2 years she had also developed a left foot weakness with increasing ‘dragging’ of the left leg and slowness of her gait, particularly when she was tired. There was no sphincter disturbance and no pain. Clinical examination revealed a spastic gait with markedly increased tone in the left lower limb, clonus at the ankle and mild weakness of hip flexion and ankle dorsi-flexion. There was hyperreflexia in both lower limbs, particularly on the left. The plantar response was down-going bilaterally. There was reduced sensation to pin-prick and temperature on the right up to the T8 level and joint position sense was reduced in both lower limbs, but more noticeably on the left. The cranial nerves and upper limbs were normal. Overall, there was a Brown-Sequard syndrome indicating a predominantly left-sided cord lesion at the T8 level. Journal of Clinical Neuroscience (2001) 8(2)
Fig. 1 T2-weighted axial MRI through T8 showing high signal CSF anterior to ventral dura indicating extradural arachnoid diverticulum.
The patient had been previously extensively investigated over the preceeding 7 years with computed tomography (CT) myelography, magnetic resonance imaging (MRI) and lumbar puncture, with no cause being found for her symptoms. More recent, higher resolution MR imaging revealed evidence of thoracic spinal cord herniation at the T8 level. On the T2 image there was a crescentic band of high signal indicating CSF between the anterior dura and the posterior margin of the thoracic vertebra (Fig. 1). The cord was closely applied to the ventral dura on the sagittal slices with apparent widening of the dorsal subarachnoid space; however there was no evidence of an arachnoid cyst and normal flow artefacts could be seen dorsal to the cord (Fig. 2). At one point, the spinal cord could be seen herniating through the left ventrolateral aspect of the dura, suggesting the diagnosis (Fig. 3). At this region the cord looked, thinner, distorted and rotated. Surgery involved a T7–9 laminectomy; the dura was opened longitudinally in the midline and CSF was expressed under considerable pressure. Multiple arachnoid adhesions were divided but there was no dorsal arachnoid cyst. The cord was gently retracted back and inspection of its left side revealed a dural defect of approximately 525 mm through which pale, yellowish, swollen cord tissue was herniating into an extradural space (Fig. 4). It was unclear whether this space represented a dural diverticulum or arachnoid meningocoele, although there was CSF epidurally. The dural defect was opened around the herniated cord. There was a significant rostral extent of the herniated segment, suggesting perhaps a tethering process by the superior edge of the dural defect. It was considered whether to place a dural graft, but the herniated cord segment caused marked distortion of the normal cord when fully reduced. By day 3 postoperatively the patient noted some improvement in the sensation on her right side and she was discharged home after 9 days. She continued to make slow improvement over the next 3 months.
DISCUSSION This case of ISCH is similar to the previously reported clinical patterns (Table 1). In the 30 cases, the age range was 23 to 71, with a mean of 49. There was a female predominance of 1.8 : 1. All cases occured in the thoracic spine from T2 to T10, and all were © 2001 Harcourt Publishers Ltd
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Fig. 3 T2-weighted axial MRI showing spinal cord herniation in left ventrolateral position.
Fig. 4 Diagrammatic representation of appearance of spinal cord segment herniating through oval-shaped dural defect.
Fig. 2 T2-weighted sagittal MRI showing thoracic cord at T8 level ventrally displaced but with normal CSF flow voids dorsally.
ventral or ventrolateral directed herniations, with a slight left-sided predominance. The clinical presentation is striking for its chronicity and gradual progression of neurological symptoms, often starting with sensory disturbance then involving the pyramidal tracts and occasionally the sphincters as well. Only 4 out of the 30 cases (13%) presented with something other than Brown-Sequard syndrome, namely paraparesis in 31–3 and monoparesis in 1.4 Sphincter disturbance was relatively common, occurring in 20%. Spinal pain was a very uncommon feature. Posture related symptoms occurred occasionally. MRI was the key to diagnosing the condition in this patient and has formed the basis for diagnosis in all the other recent cases. CT myelography has also been found to be helpful. The features seen are a ventrally displaced, often thinned cord in the upper or midthoracic region which may look distorted or rotated. The herniation itself may be visible, as in this case, as a short segment of cord situated anterior to the ventrolateral dura. The segment may be quite short in the rostral-caudal direction and non-fine-cut axial scans may miss it, which probably explained why it was missed in our patient’s original MRI. A dorsal intradural arachnoid cyst is rarely visible on imaging, even if present at operation, and © 2001 Harcourt Publishers Ltd
normal CSF pulsation artefacts or phase contrast studies1 are helpful in showing it to be absent. Myelography may show slowfilling around the herniation but again rarely shows a filling defect related to an arachnoid cyst, even if present, because many are arachnoid diverticula rather than totally encapsulated cysts. Endoscopy may be a useful adjunct as used by Miyake et al.5 preoperatively to inspect the dorsal subarachnoid space and confirm the diagnosis, and again intraoperatively to show the cord herniating into an epidural arachnoid cyst, rather than a dural diverticulum. Spinal cord herniation per se may be traumatic, iatrogenic (post spinal surgery) or idiopathic. Post surgical cases have occurred in the dorsal cervical spine some months or years after cervical laminectomy, during which a dural tear has gone unrecognised. A number of traumatic cases have been reported involving the thoracolumbar spine, which interestingly tended to present with patterns other than Brown-Sequard syndrome such as para- or monoparesis; these are uncommon in the idiopathic variety. Three idiopathic cases noted above did have a history of trauma many years prior to the episode of herniation but it was not clear if these were related to the SCH.6–8 No identifiable relationship to trauma was found at surgery, e.g. shrapnel in the third case of Borges,6 but subclinical trauma remains an etiologic possibility. There are a number of theories regarding the cause of idiopathic herniations, which can broadly be classified as congenital, Journal of Clinical Neuroscience (2001) 8(2)
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182 Morokoff et al. Table 1
Thirty-one cases of idiopathic spinal cord herniation
Year
Series
Age/sex
1974
Wortzman20
63 M
1981
Masuzawa7
36 M
1990 1991
Ohe13 Tronnier15
61 M 45 F
1991
Isu5
43 F 45 F
1993
Nazakawa12
43 F 39 F
1994
White19
61 F 39 M
1995 1995
Batzdorf1 (comment) Borges1
23 F 68 F 68 M 48 F
1995
Kumar 6
38 M
1996
Hausman4
57 F
36 M 1996
Matsumara8
63 F
1996
Miura10
49 M
1996
Sioutos14
34 F
1996
Urbach16
44 M
1997
Henry4
30 F
1997
Uchino17
71 F
1998
Miyake11
45 F 53 M
1998
Marshman9
55 F
1998
Dix3
44 F
1998
Brugieres2
54 F
1998
Watters18
70 M 55 F
1999
Current study
33 F
Clinical symptoms Brown-Sequard Left T9 Brown-Sequard Left T6 Spastic paraparesis Brown-Sequard Right T5 Brown-Sequard Right T5 Brown-Sequard Left T4 Brown-Sequard Right T3 Brown-Sequard Left T7 Brown-Sequard Right T6 Brown-Sequard Left T10 Brown-Sequard Right T6 Brown-Sequard Right T9 Brown-Sequard Left T4 Brown-Sequard Left T10 Brown-Sequard Left T8 Brown-Sequard Left T10 Brown-Sequard Left T7 Brown-Sequard Left T4 spastic right leg, sphincter dist. spastic paraparesis level T6/7 Brown-Sequard Left T6 (sens only) Brown-Sequard Right T6–T8 Brown-Sequard Left T4 Brown-Sequard Right T6 Brown-Sequard Left T6 Brown-Sequard Left T7–T8 Brown-Sequard Left T7–T8 Brown-Sequard Right T6 Paraparesis T7–T8 Brown-Sequard Left T3–T4 Brown-Sequard Left T8
D
AC
Side & level
36
No
Left T7
Thoracotomy
motor and sphincters
12
No
T4
TLY
motor and sensation
120 48
Yes No
T4–T5 T3–T4
TLY TLY
no change sensation
12
Yes
T5–T6
TLY
motor and sensation
20
Yes
T2–T3
TLY
sensation
60
No
T2–T3
TLY
motor and sensation
36
T4
TLY
motor
12
Right T4–T5
TLY
no change
Improvement
18
No
T8
TLY
no change
24
No
T6
motor at 2nd proc
108
No
T7
TLY, thor 2nd proc thoracotomy
motor and sensory
96
No
T3
TLY
motor
120
No
T7–T8
TLY
motor
24
No
T7–T8
TLY
96
No
T6–T7
84
No
T6–T7
costotransversectomy and discectomy TLY
216
Yes
T3–T4
TLY
motor and sensation worse motor and sensation
13
Yes
T5–T6
laminectomy;U/S
motor and sphincter
24
No
T6–T7
TLY
motor and sphincter
24
No
T5–T6
TLY
motor and sphincter
24
Yes
T7
TLY
24
Yes
T4–T4
motor and sensory, moderate sphincter no change
48
No
T3–T4
motor and sensation
72
No
T2–T3
endoscopy, laminoplasty laminoplasty
motor
168
No
T7–T8
laminectomy
motor and sphincter
–0
No
T7–T8
motor
60
No
T6
6 120
No No
T5–T6 midline T3–T4
laminectomy intraop U/S laminectomy resection laminectomy laminectomy2
worse motor and proprioception sensation motor and sensation
96
No
T7–T8
laminectomy
sensation
acquired or a combination. An early postulate was herniation into a duplicated dura, or dural diverticulum,6,9,10 but this has not been confirmed in many subsequent reports. Wortzman11 proposed dural injury from a ruptured thoracic disc. Miura4 noted the association with other congenital defects such as abnormal laminae, suggesting a midline fusion disorder. Probably the most dominant theory5,6,12,13 emphasises the naturally ventral position of the thoracic cord (ISCH does not occur in the cervical or lumbar Journal of Clinical Neuroscience (2001) 8(2)
Procedure
gait
region) and suggests that it may become adherent to a dural defect and then be pushed through with abnormal movements, or CSF pulsations during the cardiorespiratory cycle. The cord may be ‘sucked’ out by negative pressure in the epidural space,5 or pushed out by dorsal pressure, possibly from an arachnoid cyst.14 Uchino15 suggests, however, that the cyst may be a secondary effect from arachnoidal distortions and adhesions caused by the abnormal ventral position of the cord. The dural defect may be congenital or, © 2001 Harcourt Publishers Ltd
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Actinomyces brain abscesses 183
less likely, acquired secondary to pressure from the cord or abnormal movement of the cord. Watters16 has noted the presence of a nerve root exiting through the dural defect, suggesting a cord malformation. The clinical symptoms may be related to tethering of the cord by the margin of the dural defect. Borges6 reported a case similar to ours, where there was a significant amount of rostral cord distortion epidurally, again suggesting tethering or traction on the cord. This may be exacerbated by arachnoidal adhesions, posteriorly and around the herniation.2,4,9,13 Vascular compromise may also be a contributing factor.9,17 There is consensus regarding the presence of functional neural tissue in the herniated segment which in most cases, as in ours, appears as an abnormal, exophytic gliotic mass. Two reports describe partial resection of the herniated mass (Brugieres1 and Kumar12). The histopathological findings included hypertrophied astrocytes, pilocytic gliosis and Rosenthal fibres with normal or dilated axons. Chronic reactive change was noted.1 In the first case the patient suffered an initial deterioration followed by progressive improvement; in the second there was no postoperative deterioration. Borges6 agrees that functioning axons may be present, therefore the herniated mass should be replaced intradurally and preserved. Most authors then recommend closing the dural defect, with a dorsal patch graft if necessary. We found that this was impossible without causing excess compression of the spinal cord within the dural space. Reduction of the tethering effect of the herniation on the spinal cord may be a more important surgical goal than complete restoration of dural and cord anatomy.
CONCLUSION Idiopathic spinal cord herniation is a rare condition which affects the ventrolateral thoracic spinal cord. The pathogenesis is unclear but is probably related to pressure from the ventrally situated thoracic cord, leading to an acquired, or exacerbating a congenital, dural defect. It most commonly presents with progressive BrownSequard syndrome of months to years duration and can be diagnosed successfully with MRI. Operative decompression of the herniation usually leads to clinical improvement. REFERENCES 1.
2.
3. 4. 5. 6.
7. 8. 9. 10.
11.
Brugieres P, Malapert D, Adle-Biassette H, Fuerxer F, Djindjian M, Gaston A. Idiopathic spinal cord herniation: value of MR phase-contrast imaging. Am J Neuroradiol 1999; 20: 935–939. Ohe T, Hoshino Y, Kurokawa T. A case of idiopathic herniation of the spinal cord associated with duplicated dura mater and with an arachnoid cyst (in Japanese). Nippon Seikeigeka Gakkai Zasshi 1990; 64: 43–49. Sioutos P, Arbit E, Tsairis P, Gargan R. Spontaneous thoracic spinal cord herniation: a case report. Spine 1996; 21: 1710–1713. Miura Y, Mimatsu K, Matsuyama Y, Yoneda M, Iwata H. Idiopathic spinal cord herniation. Neuroradiology 1996; 38: 155–156. Miyake S, Tamaki N, Nagashima T, Kurata H, Eguchi T, Kimura H. Idiopathic spinal cord herniation. J Neurosurg 1998; 88: 331–335. Borges LF, Zervas NT, Lehrich JR. Idiopathic spinal cord herniation: a treatable cause of the Brown-Sequard syndrome. Neurosurgery 1995; 36: 1028–1033. Tronnier VM, Steinmetz A, Albert FK, Scharf J, Kunze S. Hernia of the spinal cord: a case report and review of the literature. Neurosurgery 1991; 29: 916–919. Urbach H, Kaden B, Pechstein U, Solymosi L. Herniation of the spinal cord 38 years after childhood trauma. Neuroradiology 1996; 38: 157–158. Dix JE, Griffith W, Yates C, Johnson B. Spontaneous thoracic spinal cord herniation through an anterior dural defect. AJNR 1998; 19: 1345–1348. Masuzawa H, Nakayama H, Shitara N, Suzuki T. Spinal cord herniation into a congenital extradural arachnoid cyst causing Brown-Sequard syndrome. J Neurosurg 1981; 55: 983–986. Wortzman G, Tasker RR, Rewcastle NB, Richardson JC, Pearson FG. Spontaneous incarcerated herniation of the spinal cord into a vertebral body: a unique cause of paraplegia – case report. J Neurosurg 1974; 41: 631–635.
© 2001 Harcourt Publishers Ltd
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15. 16.
17.
Kumar R, Taha J, Greiner AL. Herniation of the spinal cord: case report. J Neurosurg 1995; 82: 131–136. Nazakawa H, Toyama Y, Satomi K et al. Idiopathic spinal cord herniation: report of two cases and review of the literature. Spine 1993; 18: 2138–2141. Isu T, Iizuka T, Iwasaki Y, Nagashima M, Akino M, Abe H. Spinal cord herniation associated with an intradural spinal arachnoid cyst diagnosed by magnetic resonance imaging. Neurosurgery 1991; 29: 137–139. Uchino A, Kato A, Momazaki N, Yukitake M, Kudo S. Spinal cord herniation: report of two cases and review of the literature. Eur Radiol 1997; 7: 289–292. Watters MR, Stears JC, Osborn AG, Turner GE, Burton BS, Lillehei K, Yuh TC. Transdural spinal cord herniation: imaging and clinical spectra. AJNR 1998; 19: 1337–1344. White BD, Firth JL. Anterior spinal hernia: an increasingly recognised cause of thoracic cord dysfunction. J Neurol Neurosurg Psychiatry 1994; 57: 1433–1435.
Multiple actinomyces brain abscesses: case report Ming-Shih Tsai1,3 MD PHD, Jia-Jiunn Tarn4 MD, Keng-Shing Liu5 MD, You-Li Chou1 PHD, Ching-Liang Shen2 PHD 1
Institute of Biomedical Engineering, 2Department of Anatomy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan, 3Department of Neurosurgery, 4Department of Pathology, 5Department of Medicine, Tainan Hospital, Department of Health, Tainan 700, Taiwan
Summary A case of multiple cerebral abscesses caused by actinomyces is reported in a 37 year old male with mucoepidermoid carcinoma of the right lung. In conjunction with penicillin, sulfonamide and erythromycin, the patient underwent stereotactic surgery for aspiration of the brain abscesses under (CT). The bacteria, considered to originate from the right lung, were identified from the abscess material obtained at surgery. Using proper therapy to control infection and intracranial pressure is important. A long term follow up with frequent computerised tomography evaluation has been conducted and the patient outcome has been successful recovery. © 2001 Harcourt Publishers Journal of Clinical Neuroscience (2001) 8(2), 183–186 © 2001 Harcourt Publishers Ltd DOI: 10.1054/jocn.1999.0744, available online at http://www.idealibrary.com on
Keywords: actinomyces, intracranial pressure, multiple brain abscesses, stereotactic aspiration Received 18 September 1998 Accepted 8 December 1999 Correspondence to: Dr Ming-Shih Tsai, No. 2 Dong Rong Street, Tainan 701, Taiwan. Tel.: 886-6-2371087; Fax: 886-6-234-5955
INTRODUCTION Actinomyces is the most important human pathogen in actinomycetaceae and is closely related to mycobacteria and commensals within the oral cavity and alimentary tract.1 They were thought to be similar to fungi because of branching and the formation of a mycelial network but the presence of muramic acid in cell walls and the absence of a membrane bound nucleus clearly align them with the bacteria. The first report of a brain actinomycotic lesion was by Ponfick in 1882.2 Rare cases of multiple brain abscesses caused by these bacteria and the corresponding treatment leading to successful recovery have been reported in the literature.2–7 Journal of Clinical Neuroscience (2001) 8(2)