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Technical Note
1
Intra-Extramedullary Drainage as an Effective Option for Treatment of Intramedullary Ependymal Cyst of Thoracic Spine: Technical Note Alessandro Landi 1
Andrea Pietrantonio 2
Nicola Marotta 2
1 Department of Neurosurgery, DPT of Neurological Sciences, Sapienza
Rome, Rome, Italy 2 Department of Neurosurgical Sciences, University of Rome Sapienza, Rome, Italy
Cristina Mancarella 2
Roberto Delfini 2
Address for correspondence and reprint requests Alessandro Landi, Department of Neurosurgery, DPT of Neurological Sciences, Sapienza Rome, viale del policlinico 155, Rome 00151, Italy (e-mail:
[email protected]).
J Neurol Surg A 2012;00:1–5.
Abstract
Keywords
► intramedullary ependymal cyst ► cyst-subarachnoid shunt ► neurophysiological monitoring ► Nelaton drain
Background Intramedullary neuroepithelial cysts are extremely rare and only 15 cases have been reported in the literature. Clinico-radiological features are not indicative of a specific diagnosis; for this reason, diagnosis is based mainly on the histological features. In the literature, total surgical removal is considered the treatment of choice. The risk of recurrence is higher after partial removal and in cases of occlusion of intra-extramedullary shunt. For this reason, a surgical strategy that ensures the shunt patency in case of incomplete removal of the cyst becomes a very safe option for treatment of this pathology. Materials and Methods We report the case of a 51-year-old woman who was found to have a dorsal (D9) intramedullary neuroepithelial cyst. She underwent surgical treatment with partial removal and placement of a Nelaton drainage device (8 French) inside the intra-extramedullary shunt. Results The patient experienced a complete regression of preoperative symptoms and magnetic resonance imaging (MRI) follow-up showed no radiological evidence of recurrence 24 months after surgical treatment. Conclusion Spinal ependymal cysts show a high frequency of recurrence, especially in cases of partial removal of the cyst wall. Unfortunately, the cyst walls are often closely adherent to the spinal cord, making total removal impossible. Intra-extramedullary shunting is a viable option, although there is a high frequency of recurrence in cases of obstruction of the shunt. Placing an 8 Ch Nelaton drain between the dorsal columns is a reliable technique, especially in cases of partial removal. In fact, it allows continuous drainage of cyst fluid and subsequent resolution of symptoms, and it decreases the incidence of recurrences due to obstruction of the shunt.
Intramedullary ependymal cysts, also defined neuroepithelial cystsQ1, are extremely rare, and only 15 cases have been
reported in the literature.12Q2 These lesions are generally congenital disorders arising from displaced ependymal cells during embryogenesis. They differ from other congenital enterogenous cysts, which result from displaced elements
received October 16, 2011 accepted after revision May 27, 2012
Copyright © 2012 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662.
Introduction
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DOI http://dx.doi.org/ 10.1055/s-0032-1328951. ISSN 2193-6315.
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Drainage of Thoracic Spine Intramedullary Ependymal Cyst
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Figure 1 (A, B, C) Preoperative magnetic resonance imaging (MRI) showed a T8–T9 intramedullary cyst that was isointense to cerebrospinal fluid on both T1- and T2-weighted images. There was no capsular or nodular enhancement after contrast administration.
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of the alimentary canal and do not exhibit globet cell differentiation.11Q3 We report our experience and present a review of the literature, focusing on diagnosis, treatment, and follow-up.
Case Description
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A 51-year-old woman presented to our attention with complaints of back pain, difficulty in walking, and burning paresthesias in the lower limbs. Neurological examination revealed a moderate spasticity and hyper-reflexia in the lower limbs, as well as Babinski reflex and decreased touch sensation below the level of T9. Magnetic resonance imaging (MRI) with gadolinium (Gd) demonstrated a globular intramedullary lesion at the T9 level. The cyst was isointense to cerebrospinal fluid on both T1- and T2-weighted images. There was no capsular or nodular enhancement after contrast administration (►Fig. 1). The investigations (hemogram and urine examination) were normal. Neurophysiological exams such as motor-evoked potentials (MEPs) and sensory-evoked potentialsQ4 (SEPs) showed a normal pattern. Because of the rapid clinical course and the need to obtain a certain diagnosis, the patient was subjected to surgical treatment. She underwent laminectomy at T8–T9. The spinal cord bulged after dural opening, but no chromatic or vascular abnormality was noted under magnification. Under intraoperative neurophysiological monitoring (SEPs, MEPs), a median linear myelotomy was performed. When the cyst wall was opened, the cyst fluid leaked at high pressure and a broad reduction of spinal cord dimension was seen. The cyst wall was only Journal of Neurological Surgery—Part A
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partially removed, because of its close adherence to the spinal cord and the worsening in neuropathological Q5parameters during its surgical removal; the specimen was then sent for pathologic examination. For these reasons, we decided to perform a cysto-subarachnoid shunt, inserting an 8 Ch Nelaton tube inside the shunt, to prevent its obstruction and increase cyst fluid outflow (►Fig. 3Q6); we prefer not to use stitches to secure the tube, because we believe that postoperative fibrosis and glial reaction can prevent its dislocation. The dura was closed in a watertight fashion. Histological, immunohistochemical examinations and electron microscopy revealed an intramedullary ependymal cyst. Postoperative course was uneventful with complete regression of preoperative symptoms. The patient was able to walk 3 days after surgery and was discharged 2 days later. Follow-up MRI every 3 months showed no signs of recurrence, and the patient was symptom free 24 months after the surgical treatment. The last MRI, performed 24 months after surgery, revealed the shunt patency and the absence of recurrence (►Fig. 2).
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Neuropathology The cyst wall consisted of flattened epithelial cuboidal cells without a basement membrane and a thin layer of glial tissueQ8. Electron microscopy evidencedQ9 intracellular junction complex, absence of coating on the luminal surface of the cells, and membrane-bound granules in nonciliated cells. Immunohistochemistry showed positive staining for CAM5.2 (lower molecular weight keratins) and AE1/AE3 (lower and higher molecular weight keratins, respectively,
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Drainage of Thoracic Spine Intramedullary Ependymal Cyst
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Figure 2 (A, B) Magnetic resonance imaging (MRI) performed 24 months after surgery: the drainage was correctly placed and there were no signs of recurrence.
Neuroepithelial cysts are rare congenital lesions generally located inside the central nervous system (CNS). In the CNS they usually involve the paraventricular regions, frontal and parietal lobes, and subarachnoid space.11 Spinal neuroepithelial cysts are more rare than the cerebral ones and are mainly extramedullarily located; intramedullary lesions are unique and only a few cases are described in the literature. Hyman et al reported the first case of extramedullary ependymal cyst in 19386Q10; on the other hand, in 1978
Fortuna et al described for the first time two cases of intramedullary ependymal cyst.4Q11 Only 15 cases of intramedullary lesions and 7 cases of lesions involving the conus medullaris have been reported in the literature, making these lesions very rare.1–4,7,8,12,13,15–17 It is generally accepted that these lesions have a developmental origin; these cysts have been considered to arise from extruded ependymal cells, which are located close to the anterior cord substance at the time of closure of the neural tube.6 The clinico-radiological features of these lesions make the pathologic examination necessary in the differential diagnosis with other more common lesions, such as inflammatory, neoplastic, infective, and demyelinating lesions. Clinical presentation is unspecific: motor and sensory deficits, sphincter dysfunction, and mechanical and neuropathic pain can be found in different combinations in each patient. Generally, the clinical course is
Figure 3 Intraoperative picture of the drain Q7 .
Figure 4 Cyst wall consists of flattened epithelial cuboidal cells without a basement membrane and a thin layer of glial tissue.
in the cells of the cyst wall); this confirmed the diagnosis of the ependymal origin of the cyst. Pathologic samples were analyzed by two neuropathologists as per the usual protocol in our institute in cases involving rare entities (►Fig. 4).
Discussion
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Drainage of Thoracic Spine Intramedullary Ependymal Cyst slowly progressive, making the differential diagnosis with other spinal lesions sometimes difficult; however, a rapid clinical onset has also been reported in the literature.11 MRI with gadolinium-diethylene triamine penta-acetic acid (GdDTPAQ12) is the study of choice to detect neuroepithelial cysts: these lesions generally appear hypointense on T1weighted images, hyperintense on T2-weighted images, and nonenhanced on Gd-enhanced T1-weighted images.18,19 The fact that the cyst wall does not enhance helps to differentiate ependymal cysts from other spinal lesions. Histopathological examination and electron microscopy are necessary to identify the ependymal nature of these cysts: the absence of a basement membrane and the lack of large-scale glycoproteins are typical findings in pathologic samples,4 whereas the absence of a basement membrane and the presence of membrane-bound granules in nonciliated cells are highlighted in electron microscopy.5Q13 Surgical decompression is the treatment of choice of ependymal cysts, because of the their mass effect on the spinal cord. Several decompressive techniques have been reported in the literature (opening of the cyst wall and drainage; total or subtotal removal),7,15,16 but total removal of cyst fluid and the cyst wall should be the goal of surgical treatment to prevent recurrences. However, frequently these lesions are closely adherent to the spinal cord, making total removal hazardous and impossible in the absence of a clear cleavage plane.7 In these cases, as in our patient, partial removal of the cyst wall and complete removal of the cyst fluid are safer and suitable to decompress the spinal cord. Some authors perform cyst marsupialization16 or cysto-subarachnoid shunt15; however, there is a high incidence of shunt occlusion and recurrence of the disease when a simple shunt is inserted. For this reason, we decided to perform a shunting procedure and to insert a Nelaton tube inside the shunt. Through a posterior approach, a laminectomy with sparing of the supraspinous and interspinous ligaments of the adjacent levels was performed. Under neurophysiological monitoring, the cyst wall was opened and the cyst fluid leaked out; then we placed an 8-Ch Nelaton tube of a length of 1.5 cm inside the shunt. This technique maintains the patency of the shunt and allows a continuous outflow of the cyst fluid; it is useful especially when the cyst wall is closely adherent to the spinal cord and complete removal is impossible. In our opinion, it is not necessary to fix the tube, as we believe that postoperative fibrosis and glial reaction ensure good adhesion and can prevent drainage dislocation. Moreover, the use of stitches may cause posterior cord damage, resulting in severe pain, numbness, and cordonalQ14 signs. In our case, follow-up MRI every 3 months showed no signs of recurrence and the patients is symptom free; we recommend a close follow-up to identify recurrences, especially in patients who experienced a new onset of symptoms. In our experience in treating intramedullary lesions or intracanalar lesionsQ15 either oncological and not by using MEPs and SEPs10,11,14Q16Q17 with excellent results,Q18 we believe that the use of neurophysiological monitoring makes the procedure safer, especially in relation to the manipulation of the spinal cord during the introduction of the tube, and makes total removal of the cyst Journal of Neurological Surgery—Part A
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Landi et al. wall and the placement of the Nelaton tube inside the shunt more feasible.
Conclusion Intramedullary ependymal cysts are extremely rare; these lesions are frequently closely adherent to the spinal cord, making total removal not possible. Under neurophysiological monitoring, the placement of cysto-subarachnoid drainage and the introduction of an 8-Ch Nelaton tube inside the shunt proved to be a viable surgical strategy, useful mainly in cases of partial removal of the cyst wall. It allows a continuous drainage of cyst fluid, avoiding recurrences.
Conflict of Interest None
References 1 Chhabra R, Bansal S, Radotra BD, Mathuriya SN. Recurrent
2 3
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intramedullary cervical ependymal cyst. Neurol India 2003;51: 111–113 Dharker SR, Kanhere S, Dharker RS. Intramedullary epithelial cyst of the spinal cord. Surg Neurol 1979;12:443–444 Findler G, Hadani M, Tadmor R, Bubis JJ, Shaked I, Sahar A. Spinal intradural ependymal cyst: a case report and review of the literature. Neurosurgery 1985;17:484–486 Fortuna A, Palma L, Mercuri S. Spinal neuroepithelial cysts. Report of two cases and review of the literature. Acta Neurochir (Wien) 1978;45:177–185 Hirano A, Ghatak NR, Wisoff HS, Zimmerman HM. An epithelial cyst of the spinal cord. An electron microscopic study. Acta Neuropathol 1971;18:214–223 Hyman I, Hamby WB, Sanes S. Ependymal cysts of the cervicodorsal region of the spinal cord. Arch Neurol Psychiatry 1938;40:1005–1012Q19 Iwahashi H, Kawai S, Watabe Y, et al. Spinal intramedullary ependymal cyst: a case report. Surg Neurol 1999;52:357–361 Review Kumar R, Nayak SR, Krishnani N, Chhabra DK. Spinal intramedullary ependymal cyst. Report of two cases and review of the literature. Pediatr Neurosurg 2001;35:29–34 Review Landi A, Dugoni DE, Marotta N, Mancarella C, Delfini R. Spinal schwannomatosis in the absence of neurofibromatosis: A very rare condition. Int J Surg Case Rep 2011;2:36–39Q20 Landi A, Marotta N, Mancarella C, Dugoni DE, Delfini R. Management of calcified thoracic disc herniation using ultrasonic bone curette SONO-PET®: technical description. J Neurosurg Sci 2011; 55:283–288 Lalitha AV, Rout P, D Souza F,Q21 Rao S; Shailesh. Spinal intramedullary neuroepithelial (ependymal) cyst. A rare cause of treatable acute paraparesis. Indian J Pediatr 2006;73:945–946 Nagano S, Ijiri K, Kawabata R, et al. Ependymal cyst in the conus medullaris. J Clin Neurosci 2010;17:272–273 Pagni CA, Canavero S, Vinattieri A, Forni M. Intramedullary spinal ependymal cyst: case report. Surg Neurol 1991;35:325–328 Raco A, Piccirilli M, Landi A, Lenzi J, Delfini R, Cantore G. Highgrade intramedullary astrocytomas: 30 years’ experience at the Neurosurgery Department of the University of Rome “Sapienza”. J Neurosurg Spine 2010;12:144–153 Robertson DP, Kirkpatrick JB, Harper RL, Mawad ME. Spinal intramedullary ependymal cyst. Report of three cases. J Neurosurg 1991;75:312–316
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18 Lee T-C, Chen Y-L, Wai Y-Y, Wong H-F, Wan Y-L. MRI of an
medullary ependymal cyst in a 71-year-old woman. Neurosurgery 1983;13:52–54 17 Sharma BS, Banerjee AK, Khosla VK, Kak VK. Congenital intramedullary spinal ependymal cyst. Surg Neurol 1987;27: 476–480
endodermal cyst of cervicothoracic spine: a case report. Zhonghua Fang She Xue Za Zhi 2003;28:103–107Q22 19 Zahos PA, Goodman LA, Onesti ST, Michelsen WJ. Dorsal endodermal cyst of the upper cervical spine. J Spinal Disord 1996;9: 536–539
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Author Query Form (JNLSA/110538TN) Special Instructions: Author please write responses to queries directly on proofs and then return back. Q1: This could be ambiguous as written. Is the meaning (1) "Intramedullary ependymal cysts, also known as neuroepithelial cysts, are..." or (2) "Intramedullary ependymal cysts, and also defined neuroepithelial cysts, are..."? Q2: The citation to Reference 12 appears to be out of order. Q3: The citation to Reference 11 appears to be out of order. Q4: MEPs and SEPs correct as expanded here? Q5: Neurophysiological? Q6: The citation to Figure 3 appears to be out of order. Q7: Logo OK on image? Q8: Potentially ambiguous. Does this mean (1) "without a basement membrane and without a thin layer of glial tissue" or (2) "consisted of a thin layer of glial tissue and flattened epithelial cuboidal cells without a basement membrane"? Q9: What does "evidenced" mean here ("Electron microscopy evidenced..")? Demonstrated? Showed? Q10: The citation to Reference 6 appears to be out of order. Q11: The citation to Reference 4 appears to be out of order. Q12: GdDTPA correct as expanded? Q13: The citation to Reference 5 appears to be out of order. Q14: Unclear Q15: Please confirm "intracanalar lesions" correct. Cannot confirm this spelling. Q16: The citation to Reference 10 appears to be out of order. Q17: The citation to Reference 14 appears to be out of order. Q18: This text is unclear: "in treating intramedullary lesions or intracanalar lesions either oncological and not by using MEPs and SEPs10,11,14 with excellent results" Q19: Medline does not index articles before 1960. Please verify the date in reference 6 "Hyman, Hamby, Sanes, 1938". Q20: Reference 9 "Landi, Dugoni, Marotta, Mancarella, Delfini, 2011" is not cited in the text. Please add an intext citation or delete the reference. Q21: Unclear authors name Q22: Medline indexes "Zhonghua Fang She Xue Za Zhi" but cannot find a listing for reference 18 "Lee, Chen, Wai, Wong, Wan, 2003". Please check the reference for accuracy.
