Arnold-Chiari malformation

Many spinal cord lesions have been described previously, in association with Chiari I lesions. The authors report a unique case of a 29-year-old patient with a Chiari I malformation and an upper thoracic epidural lesion causing headaches, dysphagia and Brown-Sequard syndrome. The patient underwent a suboccipital decompression as well as a thoracic laminectomy and resection of the epidural lesion. Pathologic analysis revealed that the thoracic lesion was fibro-adipose tissue. A review of the literature failed to show any other similar cases. We discuss the possible etiologies of this case. [Neurol Res 2003; 25: 427-429]

Keywords: Brown-Sequard syndrome; Chiari I malformation; epidural lesion; fibroadipose tissue; thoracic spine

INTRODUCTION

Spinal lesions associated with Chiari I malformations include: syringomyelis (1), scoliosis (1), occipitalization of the atlas (2), basilar invagination (3), spondylolysis (4), and diastematomyelia (5). To our knowledge, this is the first case report of a Chiari malformation associated with epidural fibro-adipose tissue causing Brown-Sequard syndrome.

Case REPORT

This 29-year-old right handed female complained of occipital neuralgia and dysphagia of three years duration, in addition to recent right leg weakness, left leg numbness and occasional urinary retention. She denied any history of trauma.

Examination

Examination of the back failed to reveal any cutaneous lesions, stigmata of dysraphic conditions or scoliosis. On neurologic examination, no cranial nerve or brainstem abnormalities were noted. The right leg strength was 4/5 proximally and distally. Sensory examination revealed a deficit to pain and temperature on the left side starting at the T4 level. She was noted to be hyper-reflexive in the right leg with a positive Babinski. MRI showed a Chiari malformation (Figure 1) as well as an epidural lesion at the T1-T3 level on the eccentric to the left, pushing the cord anteriorly (Figures 2 and 3). Plain X-rays did not reveal any bony abnormalities.

Operation

With the patient in prone position under general anesthesia, a suboccipital craniectomy and duraplasty was performed. Next, a T1-T3 laminectomy was performed. A vascular, soft, fleshy extradural mass was noted to compress the spinal cord and indenting it. Once this tissue was removed, the dura was opened, no other anomalies such as a dural defect were noted. The spinal cord appeared normal without any evidence of herniation.

Post-operative course

Within hours post-operatively, the patient noted improvement in both sensation and strength in the lower extremities. After 48 h, she had partially recovered thermal sensation in the trunk and left leg, and her right leg strength was almost normal. Her occipital neuralgia and dysphagia gradually improved. At six month follow up examination, the patient's lower extremity strength continues to improve. Sensation is almost normal on her left side. Post-operative MRI (Figure 4) reveals less displacement of the cord anteriorly.

Pathology

Pathologic analysis of the epidural mass was consistent with fibroadipose tissue (Figure 5).

DISCUSSION

Previous reports have proposed that an early paraxial mesodermal insufficiency may be the original anomaly common to all the different malformations that constitutes the heterogeneous group of cephalic axial skeletalneural dysraphic disorders6. Whether or not the epidural lesion is congenital or not and thus part of the Chiari complex, is debatable. Fibro-adipose tissue is found in the normal spinal epidural space. It is possible that this case might represent focal hypertrophy/hyperplasia of this tissue type. Indeed there have been many reports of spinal extradural lipomas, angiolipomas, angiomyolipomas and lymphangiolipomas causing symptomatology. Our case report is similar to a previously reported case of a cervicothoracic epidural, vascular lipoma associated with a cervical dysraphism in a young boy7. This raises the possibility that spinal extradural connective tissue anomalies might coexist with other congenital lesions and become manifest as they get larger over time. The possibility of spinal cord herniation through a ventral dural defect was also considered pre-operatively, although the lack of any dural defect during the operation did not support this diagnosis.

REFERENCES

1 Ghanem IH, Londono C, Delalande O, et al. Chiari I malformation associated with syringomyalia and scoliosis. Spine 1997; 22: 1313-1317

2 Hultman CS, Riski JE, Cohen SR, ef al. Chiari malformation, cervical spine anomalies, and neurologie deficits in velocardiofacial syndrome. Plast Reconstr Surg 2000; 106: 16-24

3 Goel A, Bhatjiwale M, Desai K. Basilar invagination: A study based on 190 surgically treated patients, J Neurosurg 1998; 88: 962-968 4 Bowen JD, Malanga GA. Spondylolysis associated with Arnold-Chiari malformation and syringomyalia. A report of two cases. Spine 1997; 22: 2458-2463

5 Davis ED. Diastematomyelia with early Arnold-Chiari syndrome and congenital dysplastic hip. Clin Orthop 1967; 52: 179-185

6 Marin-Padilla M. Cephalic axial skeletal-neural dysraphic disorders: Embryology and pathology. Can J Neurol Sd 1991 ; 18: 153-169

7 Hinton JL Jr, Robinson JS Jr. An unusual epidural, vascular spinal lipoma in a 3-year-old child: A case report and review of the literature. Surg Neurol 1990; 34: 323-326

Kaveh Barami, lan Lee, Jody Wellwood and Daniel B. Michael

Department of Neurosurgery, Detroit Receiving Hospital, Wayne State University, Detroit, MI, USA

Correspondence and reprint requests to: Kaveh Barami, MD, PhD, 4201 St. Antoine, UHC-6E, Detroit, Ml 48201, USA.

[kbarami@neuosurgery.wayne.edu] Accepted for publication February 2003.

Copyright Forefront Publishing Group Jun 2003
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