Acta Neurochir (2012) 154:341–348 DOI 10.1007/s00701-011-1110-6
CLINICAL ARTICLE
Thoracolumbar extradural arachnoid cysts: a study of 14 consecutive cases Jae Keun Oh & Dong Youp Lee & Tae Yup Kim & Seong Yi & Yoon Ha & Keung Nyun Kim & Hyunchul Shin & Dong Seok Kim & Do Heum Yoon
Received: 28 May 2011 / Accepted: 19 July 2011 / Published online: 13 August 2011 # Springer-Verlag 2011
Abstract Background To investigate characteristic clinical and radiological features of extradural arachnoid cysts (EDACs) in the thoracolumbar region, a retrospective review of medical records and imaging studies was performed. EDACs are well known but relatively rare lesions in the thoracolumbar spinal canal. The most common site is the lower thoracic spine, and it may cause neurological symptoms by compressing the spinal cord or nerve root. In this study, the pathogenesis, symptomatology, diagnostic approach, and surgical management of EDACs will be discussed. Methods We studied 14 consecutive patients who were surgically treated for EDACs in the thoracolumbar region at our institute between March 2000 and January 2011. The history, clinical presentations, image findings, operative J. K. Oh : T. Y. Kim : S. Yi : Y. Ha : K. N. Kim (*) : D. H. Yoon Department of Neurosurgery, Spine and Spinal Cord Research Institute, Yonsei University College of Medicine, 250 Seonsanno, Seodaemun-Gu, Seoul, Republic of Korea e-mail:
[email protected] D. Y. Lee Department of Neurosurgery, Yonsei Barun Hospital, 147-29 Sadang-Dong, Dongjak-Gu, Seoul, Republic of Korea H. Shin Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University College of Medicine, 108 Pyoung-Dong, Jongro-Gu, Seoul, Republic of Korea D. S. Kim Department of Pediatric Neurosurgery, Severance Children’s Hospital, Yonsei University College of Medicine, 250 Seonsanno, Seodaemun-Gu, Seoul, Republic of Korea
findings, and surgical outcomes of these patients were retrospectively analyzed. The mean follow-up period was 28 months (range: 6–72 months). Results Progressive motor weakness was the predominant symptom in all patients. Nine patients had radicular leg pain and back pain in the thoracolumbar area. On MRI, the cyst compressed the dural sac and spinal cord posteriorly typically with bilateral foraminal extensions. On radiological study, a communication point with the subarachnoid was hardly observed. The surgical treatment of EDACs included complete resection of the walls and closing the communicating point with the subarachnoid space. All patients showed excellent outcomes according to Odom’s criteria without recurrence. One CSF leakage and one postoperative hematoma were noted. Conclusions Thoracolumbar EDAC patients presented paraparesis and leg pain. Complete excision and closing the communicating point with the subarachnoid space were the choices of treatment, and the outcomes were favorable. Keywords Arachnoid cyst . Clinical outcome . Extradural . Thoracolumbar
Introduction Extra- and intradural arachnoid cysts of the spine, also called arachnoid diverticula or pouches, are uncommon and rarely produce spinal cord compression. Most of the cysts are asymptomatic and are incidentally detected during diagnostic or therapeutic procedures. The cysts may be intradural, extradural or perineural, and they may communicate with the subarachnoid space. Their etiology and pathogenesis are still being debated. Different theories exist on the pathogenesis of these cysts. It
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is believed that the cysts are formed as a protrusion of arachnoid through a small dural defect. They can occur extra- or intraspinally and are commonly located in the posterolateral aspect of the thoracic or sacral spine, displacing the spinal cord anteriorly. The most common site is the lower thoracic spine, and it may cause neurological symptoms by compressing the spinal cord or nerve root. The lesion is generally located posteriorly or posterolaterally within the spinal canal and typically extends into the neural foramina. So far, there is no article with large series cases with thoracolumabar extradural arachnoid cysts in one institute. In this paper, we present our experience of treatment of 14 consecutive cases of huge epidural arachnoid cysts between 2000 and 2011 along with a brief review of the literature on the subject and the discussion of the etiology, clinical symptoms, diagnosis, and treatment methods.
Methods Patients We evaluated 14 patients [5 men and 9 women, mean age: 34.8 years (12–77 years)] with different symptoms and signs for symptomatic spinal arachnoid cysts between December 2000 and January 2011. Only patients who were considered to have an “idiopathic” lesion were included, and other patients with brief causes, such as post-traumatic, postoperative, and
Fig. 1 (a and b) Intraoperatively, a huge pulsatile epidural cyst was located dorsally, extending through the long vertebral segments. (c) Cystic excision was carefully made, and all patients underwent careful marsupialization between the cystic wall and the surrounding structures. (d) The dural defect between the cyst and the subarachnoid space was closed by dural clipping and ligation
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post-inflammatory causes, were excluded. Histopathological diagnosis was confirmed by surgery. The histopathological findings satisfied the diagnostic criteria for typical arachnoid cysts. Radiological diagnosis The patients were examined with plain radiographs, myelography, myelo-computed tomography (CT) scanning, magnetic resonance imaging (MRI) and myelo-MR. Reconstructive coronal and sagittal images of delayed myelo-CT or myelo-MR were used to detect the connection site between the cyst and subarachnoid space in eight cases. Surgery Laminotomy was performed from the upper portion through the lower portion of the cystic level. We found a dural defect or stalk using a microscopic surgical technique in 13 cases. Intraoperatively, a huge pulsatile epidural cyst was located dorsally, extending through the long vertebral segments (Fig. 1a, b). The cyst wall was transparent, and there was colorless fluid in the cyst. Cystic excision was carefully made, and all patients underwent careful marsupialization between the cystic wall and the surrounding structures (Fig. 1c). The dural defect was frequently noted in the axillar portion of each involved root in the
Sex/age (years)
F/46
F/24
F/26
M/26
M/49
M/25
M/42
F/77
M/45
F/44
F/12
F/61
M/14
F/21
Case
1
2
3
4
5
6
7
8
9
10
11
12
13
14
T11–T12
T10–L2
T12–L2
T9–L4
T12–L1
T10–L2
T12–L2
L1-2-3-4
T11–L2
T11–L2
L1–2
T10–L1
T10–L2
T11–L3
Level
Paraparesis, back pain, pain in both legs Paraparesis, back pain, Rt radiculopathy Back pain, Rt radiculopathy Paraparesis, back pain, pain in both legs Paraparesis, back pain, numbness in both legs Paraparesis, back pain, pain in both legs Back pain, Lt radiculopathy Paraparesis, back pain, foot drop Paraparesis, Lt radiculopathy Paraparesis, Rt radiculopathy Back pain, Rt radiculopathy
Monoparesis, back pain, Lt radiculopathy
Paraparesis, back pain, Rt radiculopathy Paraparesis, back pain
Clinical symptoms
Table 1 Summary of thoracic and thoracolumbar arachnoid cysts
3 month
1 month
1 year
6 month
3 months
1 month
1 month
1 year
2 mo
3 months
1 month
1 month
2 months
6 months
Duration
Hypesthesia and dysesthesia in Rt L4-5 dermatome
G 4/5 power on Rt leg
G 4/5 power on Lt leg
Hypesthesia and dysesthesia in Lt L2-3 dermatome G 3/5 power in both legs
G 4/5 power in both legs
G 4/5 power in both legs
Hypesthesia and dysesthesia in Rt L2-3 dermatome G 3/5 power in both legs
G 4/5 power in Rt leg
G 4/5 power in both legs
G 4/5 power on Lt leg
G 4/5 power on both legs
G 4/5 power on both legs
Neurological signs
L1–2 laminectomy and cyst excision dural neck repair at L1 Rt T11–L2 laminoplasty and cyst excision dural neck repair at T11 Lt T12–L1 laminectomy and cyst excision dural neck repair at T11 Lt T10–L1 laminoplasty and cyst excision dural neck repair at T12 Lt T12–L2 laminectomy and cyst excision originated at L1/2, Lt root sleeve T10–L2 laminectomy and cyst excision originated at T12, Rt root sleeve T10–L2 laminectomy and cyst excision originated at T11, Rt root sleeve
T12–L2 laminoplasty and cyst excision dural neck repair at T11 Rt T10–L1 laminoplasty and cyst excision dural neck repair at T11 Rt 1st: T11–12 laminoplasty and cyst excision, dural neck repair at T11 Lt 2nd: T11.12 laminectomy and hematoma removal L1–2 laminectomy and cyst excision dural neck repair at L1 Lt T11–L1 laminoplasty and cyst excision dural neck repair at L1 Rt T11–L1 laminoplasty and cyst excision dural neck repair at T12 Rt L1–4 laminoplasty and cyst excision
Operation and findings
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Good
Excellent
Excellent
Excellent
Fair
Excellent
Excellent
Outcome
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Results Clinical features and symptomatic differences
Fig. 2 Plain radiographs demonstrated widening of the interpedicular distance, slender pedicles, and widened foramina, which suggested progressive widening of the spinal bony canal and long-standing lesions
thoracolumbar junction. The dural defect between the cyst and the subarachnoid space was closed by dural clipping and ligation. The dural repair was performed with prolene 5–0 selectively or dural closing with a VCS clip (Surgical clip, U&I Co., Seoul, Korea) under a surgical microscope (Fig. 1d). After removal of the cyst, laminoplasty was performed to prevent postoperative complications at the thoracolumbar junction. Assessment of clinical outcome For evaluation of the surgical results, Odom’s criteria were used as follows: excellent (no pain and no neurological deficit); good (occasional, mild pain and no neurological deficit and no change in work status); fair (frequent, persistent pain and slightly improved neurological deficit and some change in work status); poor (disabling pain and unchanged neurological deficit and unable to work). The clinical outcome was assessed according to the Prolo functional economic outcome rating scale by analyzing sensory impairment, dysesthesia, parasthesia, motor weakness, gait character, and bladder and bowel function. Statistical analysis The Wilcoxon rank sum test was performed using SPSS 12.0 (SPSS, Chicago, IL). A p value of
