Original Article Management of Pediatric Spinal Tumors · Pediatric tumors, Spinal tumors, Ependymoma, Astrocytoma, Neurophysiological monitoring Background: spinal tumors constitute

Egyptian Journal of Neurosurgery Volume 30 / No. 1 / January - March 2015 63-70

Egyptian Journal of Neurosurgery

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Original Article Management of Pediatric Spinal Tumors

Mohamed A. El Beltagy*

Chief Neurosurgeon, Children's Cancer Hospital Egypt (CCHE, 57357). Consultant Neurosurgeon and Assistant Professor, Neurosurgery Department,

Kasr Al-Ainy School of Medicine, Cairo University, Egypt

ARTICLE INFO ABSTRACT Received: 11 March 2015 Accepted: 18 April 2015 Key words: Pediatric tumors, Spinal tumors, Ependymoma, Astrocytoma, Neurophysiological monitoring

Background: spinal tumors constitute about 8 % of central nervous system tumors. They are not uncommon in pediatric population. Objectives: The author reviews his experience in surgical aspects and techniques of management of this subtype of pediatric tumors. Patients and Methods: Medical records of twenty five pediatric patients with spinal tumors admitted to Children's Cancer Hospital- Egypt (CCHE-57357) during the period from July 2007 to June2012 were retrospectively reviewed as regard details of clinical presentation, surgical aspects, tumor pathology, surgical outcome and complications. Mean age at presentation was 3.8 years (range 1.5-16). Male to female ratio was 1.3:1. Results: Commonest initial presentations were motor deficits, sphincteric disturbance, sensory deficits and pain in twenty two (88%), ten (40%), fifteen (60%), twelve (48%) patients, respectively. Commonest tumors were ependymomas and astrocytomas (40%). Rare entities included chondrosarcoma and Bilharzioma. Extent of surgical excision was: total excision was achieved in 36%, near-total/subtotal excision in 48% and biopsy in 16%, respectively. Postoperatively, neurological deficits improved in twelve cases, stabilized in eleven cases and aggravated in two cases, respectively). Intraoperative ultrasonography was utilized in nineteen cases. Intraoperative neuro-physiological monitoring was utilized in twenty cases. Anal EMG was the only positive indicative parameter for intraoperative guidance in five cases. Conclusion: Management of pediatric spinal tumors is challenging. Our management strategy relies mainly on optimizing safe and maximal tumor excision in cases when there are clear cleavage planes and avoiding total excision in infiltrating tumors. Frozen section pathology is mandatory to decide further surgical attitude. Advanced surgical adjuncts are mandatory for safe and effective surgery of spinal tumors especially intraoperative neurophysiological monitoring and ultrasonography. Anal EMG is of special importance and should not be neglected. Tumor resection should always be controlled by intraoperative neuro-physiological monitoring.

© 2015 Egyptian Journal of Neurosurgery. Published by MEDC. All rights reserved

INTRODUCTION

Primary spinal tumors account for approximately

8% of all central nervous system neoplasms.6,17,24

Spinal tumors are especially challenging in children. Moreover, about 12% of spinal tumors arise during the first year of life.4

Pediatric spine tumors entails a diverse collection of pathologic diagnoses that differ markedly based on location and age of the child. Children can be affected both by primary and metastatic tumors, thus, making the differential diagnosis and management options extensive.3

* Corresponding Author: Mohamed A. El Beltagy, MD Chief Neurosurgeon, Children's Cancer Hospital Egypt (CCHE, 57357). Consultant Neurosurgeon and Assistant Professor, Neurosurgery department, Kasr Al-Ainy School of Medicine, Cairo University, Egypt. E-mail: [email protected], Tel: + 01227457973, +2 01111185805

Spinal tumors are potentially incapacitating.

Clinical picture of spinal cord compression is the usual presentation in about 28-76% of cases.1,2,8,14

As the spinal cord is less tolerant to radiotherapy than the brain. Surgery is usually the first line option for these patients.16

Recent advances in surgical adjuncts and operative techniques give good opportunity for achieving safe surgery and good outcome.

PATIENTS AND METHODS

Patient Population

This retrospective study included twenty five pediatric patients diagnosed with spinal tumors, of which, fourteen were males and eleven females with a mean age of 3.8 years ranging from 1.5–16 years. The

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patients were treated at Children’s Cancer Hospital Egypt (CCHE-57357) between July 2007 and June 2012. Clinical assessment

Demographic data including patient sex and the age at presentation were collected. Clinical data including the presenting symptoms and signs, tumor pathology, surgical plan, operative findings and techniques utilized, complications and neurological outcome during the follow-up period were reported and analyzed. Neuroimaging

Series of magnetic resonance imaging (MRI) studies for the whole spine without and with Gadolinium contrast were performed routinely for each case: preoperatively, early post-operatively—within twenty four hours of surgery—to assess the extent of tumor resection, and then every three months for follow-up.

Initial MRI study of the brain was obtained as baseline to exclude concomitant cranial pathology. Computed Tomography (CT) study for the brain was obtained whenever hydrocephalus is suspected especially in cervical intramedullary spinal cord tumors (IMSCTs). Surgical management

In tumors arising in cranio-cervical, cervical or cervico-dorsal locations, patient head was fixed in three pin head holder or gel-padded holder in order to keep a reasonable degree of stability and flexion.

Intraoperative neurophysiological monitoring was utilized in twenty cases. Somatosensory evoked potential (SSEP) and Motor evoked potential (MEP) including anal electromyogram (EMG) were utilized.

It was important to insert all needles after good disinfection of skin puncture sites especially perianal area. Also, good fixation of wires and electrodes with adhesive tapes is empirical to avoid intraoperative malfunction while patient is positioned prone.

In lesions caudal to cervical cord we used lower limb muscle groups for EMG especially quadriceps, hamstrings, tibialis anterior and gastrocnemius muscles in addition to anal EMG and SSEP from posterior tibial nerve. One reference electrode was inserted in one triceps muscle to obtain a baseline EMG curve of a surely normal muscle. In cases with cervical cord lesions electrodes from both upper limbs muscle groups were added plus SSEP from median nerves.

In cases with cervicomedullary extension, monitoring of lower cranial nerves was applied especially via soft palatal and oropharyngeal electrodes which were inserted after intubation with the aid of a Magill forceps and were secured in place by adhesive tapes at the corners of the mouth and gauze packing of the oral cavity.

Anesthesiologists are informed as regards avoiding paralytic agents and minimizing volatile anesthetic gases during the procedure. All device connections were checked for integrity and security. Special care was directed towards avoiding iatrogenic injury to anatomical structures during insertion of needles especially median nerve, brachial artery, posterior tibial nerve and sural nerve.

Appropriate spinal level and skin marking were determined with the aid of intraoperative C-arm fluoroscopy

Systemic antibiotics were administered in recovery room forty five minutes before patient enters the operative room.

Attention was paid to meticulous hemostasis in each step from skin to dura with special care given to minute bony ooze to be sealed with bone was. A clean and dry operative field was a must before dural opening.

Determination of solid part of the lesion was double checked by C-arm fluoroscopy and transdural ultrasound.

In intradural lesions, the dura was then opened under surgical microscope. Dural stay sutures to the muscles were taken. Careful arachnoid opening was done and arachnoid was stitched to the dura for closure at the end of the procedure.

Appropriate site for myelotomy (usually midline unless the tumor paves another clear way) was determined by intraoperative ultrasound and guidance of intraoperative neurophysiological monitoring.

Myelotomy was performed with micro dissector, micro forceps and micro scissors. Bipolar and unipolar diathermy were seldom used at low power to avoid heat production.

Care was taken to choose appropriate non-injurious suction pieces and suitable suction power at each step.

Cleavage tissue planes were searched for. One should not abruptly enter into the lesion for debulking before ascertaining that the lesion is not a rare unexpected one such as arterio-venous malformation, aneurysm or cavernoma.

If good cleavage planes were detected, trials at total excision were attempted but again, with guidance of neurophysiological monitoring. However, if no good tissue cleavage planes were detected, it's hazardous to harshly manipulate on normal cord tissue to try total excision. In these circumstances and with neurophysiological guidance, it is wise to obtain a safer near total or subtotal excision. Some IMSCTs were inoperable and even untouchable, in those, only the smallest biopsy was allowed.

Intraoperative ultrasonography was utilized to aid localization and step-wise tumor resection control.

Intraoperative loading dose of methyl prednisolone was given to fourteen patients to avoid postoperative new deficits.


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RESULTS

The study included twenty five children with different spinal tumors. There was slight male predominance. Mean age at presentation was 3.8 years (range 1.5 to 16 years). The mean duration of symptoms was six months.

The most common clinical presentation was motor deficits in twenty two cases (88%), sensory deficits in fifteen cases (60%), and pain in twelve cases (48%) and sphincteric affection in ten cases (40%).

According to tumor location, eleven tumors were intramedullary, three tumors were intradural-extramedullary, six tumors were intracanalicular-extradural, three tumors affected the vertebral body with

extradural extension and two tumors affected vertebral body only.

Cervical and dorsal spinal cord locations were the commonest in this study being nine (36%) and eight (32%) cases, respectively.

Commonest tumor pathologies encountered were ependymomas and astrocytomas in six (24%) and four (16%) cases, respectively. There were other pathology entities such dorsal primitive neuroectodermal tumor (PNET). Also, there was an interesting case of cauda equina space occupying lesion with total excision was accomplished. The lesion turned out to be a Bilharzial granuloma. Antibilharzial medical treatment was given to the patient who had gradual improvement of his motor and sphincteric deficits. Table 1 shows the different pathological entities within the studied cases.

Table 1: Different pathological entities in the study Location Intradural

Intramedullary (11 cases)

Intradural extramedullary (3 cases)

Intracanalicular Extradural (6 cases)

Vertebral body (2 cases)

Vertebral body and extradural (3 cases)

Ependymomas 6 - - - - Astrocytomas 4 - - - - Bilharzioma 1 - - - - Arachnoid cyst - 1 - - - Schwannoma - 1 - - - Dermoid cyst - 1 - - - Neuroblastoma - - 3 - - Metastatic synovial sarcoma

- - 1 - -

Chondrosarcoma - - 1 - - Ewing sarcoma/PNET - - 1 - - Osteochondroma - - - 1 - Metastatic osteosarcoma - - - 1 - Metastatic Ewing sarcoma - - - - 1 Chordoma - - - - 1 Giant cell tumor - - - - 1

Intraoperative ultrasonography technology was utilized in nineteen cases (76%). Intraoperative neurophysiological monitoring techniques were utilized in twenty cases (80%). Setup for motor evoked potential (MEP) including anal EMG and somatosensory evoked potential (SSEP) was prepared after induction of anesthesia while the patient is still supine. Anal EMG was the only positive indicative parameter for intraoperative guidance in five cases.

Total excision was performed in nine cases (36%). Near total or subtotal excision was achieved in twelve cases (48%) while only biopsy was possible in four cases. Total excision was achieved in 50% of ependymomas and in 25% of astrocytomas. Tumor recurrence was encountered in two cases. one of them was anaplastic ependymoma and the other was anaplastic astrocytoma.

Postoperatively, neurological deficits improved in twelve cases, stabilized in eleven cases and worsened in two infiltrating astrocytoma cases. Four patients showed transient deterioration of the neurological functions with gradual improvement over five days to eight weeks.

Postoperative hydrocephalus occurred in three cases with cervical lesions. Cerebrospinal fluid (CSF) diversion in the form of ventriculo-peritoneal shunts was needed in these cases.

Superficial wound infections occurred in two cases. In one of them, surgical debridement was performed.

DISCUSSION

Revolution in neuroimaging especially the gold standard high quality MRI had led to significant improvement in diagnosis, assessment and followup of spinal tumors.5,13,23



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Marvelous advances in microsurgical techniques and technologies made safe and effective management of spinal tumors possible.10,15,21

Early diagnosis and early management of pediatric spinal tumors remain the most crucial elements affecting the outcome of such tumors.7

In this study, the most common clinical presentation was motor deficits, sensory deficits, pain and sphincteric affection in 88%, 60%, 48% and 40% of cases, respectively.

Postoperatively, neurological deficits improved in twelve cases (six of which had total excision of their lesions), stabilized in ten cases and worsened in two cases.

It appears that neurologic improvement after surgery is more likely in patients undergoing total resection than in patients undergoing partial resection.19

Hence, gross total resection should be the aim, but if the cleavage plane between tumor and cord is unclear, then near total/subtotal resection would still be beneficial.6

In this study, ependymomas and astrocytomas are the most frequent intramedullary tumors. Ependymomas of the spinal canal may be located intramedullary, attached to the filum terminale, or even extradurally originating from heterotopic ependymal cells.14-15 In this study, ependymomas and astrocytomas constituted collectively 40% of the study cases.

In the literature, overall rates for complete resections vary between 23% and 81%.8,10,22,19 In the current study; overall total excision rate was achieved in nine cases (36%). Near total or subtotal excision was achieved in twelve cases (48%) while only biopsy was possible in four cases. Total excision was achieved in 50% of ependymomas and in 25% of astrocytomas.

The extent of resection varied according to the nature of the lesion and whether good tumor-normal cord interface was clear. Excision was safe when there had been good cleavage planes around the tumor. In many cases that was not the situation. Tumor cleavage planes are more evident in ependymomas than in astrocytomas which are more infiltrative. We had gross total resection in 50% of ependymomas as compared to 25% in astrocytomas due to lack of intraoperative clear dissection planes and in many astrocytoma cases MEP or SSEP gave us warning signals that hindered safe total excision.

Three astrocytoma cases had non-total surgical excision. Those cases received adjuvant chemotherapy according to the low grade glioma chemotherapy protocol adopted in our center.

On the other hand, three cases of ependymoma with postoperative residual were subjected to adjuvant conformal radiotherapy. Figure 1 & 2 show two cases of spinal cord ependymoma with different extents of surgical resection.

a b Fig. 1 a&b: A seven years old male presented with paraparesis due to dorsal intramedullary lesion. a: Preoperative sagittal T1 weighted (T1W) MRI with contrast showing dorsal intramedullary lesion with solid and cystic components. b: Early postoperative T1W MRI with contrast showing debulking of the tumor as guided by intraoperative neurophysiological monitoring. The lesion proved to be tanycytic ependymoma grade II according to the World Health Organization (WHO) classification of brain tumors

a b Fig. 2 a&b: One year old female patient presented with paraparesis urinary retention. a: Preoperative sagittal T1W MRI with contrast showing dorsal intramedullary lesion with large dorsal intramedullary space occupying lesion causing fusiform swelling of the spinal cord. The lesion shows moderate contrast enhancement and it has polar cysts. b: Early postoperative T1W MRI with contrast showing almost total excision of the lesion. It proved to be cellular ependymoma.

Spinal intradural extramedullary tumors constitute about 25% of spinal tumors in children.16 In the current study; three cases (12%) had their lesions intradural and extramedullary. One case was an arachnoid cyst. Opening of cyst and marsupialization of its walls was performed followed by insertion of simple cysto-peritoneal tube. Another case was a dermoid cyst which was surgically excised. The third case was a schwannoma which was totally excised (Fig. 3 a-d).

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a b c d Fig. 3 a-d: Fourteen years old male patient presented with low back pain and sciatic pains. a & b: Preoperative sagittal T1W and T2W MRI showing lumbar intradural space occupying lesion at the level of second and third lumbar vertebrae. c & d: Early postoperative T1W and T2 weighted (T2W) MRI showing total excision of the lesion. The lesion proved to be Schwannoma of the filum terminale.

Six cases had purely intracanalicular extradural

lesions. Among which there had been a case with left hip synovial sarcoma which showed progression and extradural metastasis for which decompressive laminectomy was performed together with excision of the extradural lesion.

Also, two cases presented with affection of vertebral bodies with intracanalicular extradural

extension. One of which was a female with osteosarcoma of the humerus that showed metastasis to the lung and the fifth lumbar vertebra with extradural extension (Fig. 4 a-d). The other case was a craniocervical chordoma for which total surgical excision was performed (Fig. 5 a-b).

a b c d Fig. 4 a-d: Twelve years old female patient who had an osteosarcoma of the left humerus. She presented later on with agonizing low back pain and mild paresis of her lower extremities. a & b: Preoperative sagittal T1W and T2W MRI showing uniform abnormal hyper intense signals of the body of the fifth lumbar vertebra together with extradural mass compressing the thecal sac at the same level. c & d: Early postoperative T1W and T2W MRI showing decompression of the spinal canal and excision of the extradural soft tissue component. The lesion proved to be metastatic osteosarcoma.



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a b Fig. 5 a-b: 7 years old male patient presented with neck pain and abnormal gait. a: Preoperative sagittal T1W MRI with contrast showing anterior extradural cervical lesion opposite the upper four cervical vertebral bodies and exerting a mass effect on the opposing cervical spinal cord. b: Early postoperative T1W MRI with contrast showing total excision of the lesion which proved to be chordoma.

Binning et al reported that about 3-5% of children with systemic cancer present with spinal cord compression.3 However, we encountered spinal cord or thecal sac compression in three cases in this study. Interestingly, the tumors of origin were all skeletal namely osteosarcoma, synovial sarcoma and Ewing's sarcoma.

In this study there had been one case of conus medullaris lesion that had undergone surgery for excision of the lesion and the lesion turned out to be a Bilharzioma. This highlights the fact to deal with any IMSCT cautiously. Neat and careful surgical approach to such subtype of lesions is important as those lesions may turn out to be vascular malformations or rare non-neoplastic lesion.

In every case, whenever possible, the extent of resection should be monitored by intraoperative neurophysiological monitoring. Due to unique anatomical locations within spinal cord, when SSEPs are still intact, surely motor tracts are still good while when SSEPs become abnormal, motor tracts may or may not be affected yet. Thus, MEPs are more representative to motor function however SSEPs are good positive but not good negative. Although intraoperative neurophysiological monitoring is very beneficial in surgery of IMSCTs, it’s of little help in cases of spinal extradural lesions.

Overall tumor recurrence rates of 24% were reported.9 We experienced tumor recurrence in two cases one of which was anaplastic astrocytoma and the other one was anaplastic ependymoma. The significant variation in recurrences between benign and malignant spinal tumors is self-explanatory.9

Reinsertion of the vertebral lamina is supposed to preserve normal anatomical planes and minimize

formation of pseudomeningocele. However, such an effect has not been proven in adults and could only be demonstrated for children.16,

Intraoperative loading dose of methyl prednisolone was given to fourteen patients whenever there was suspicion or a will to prevent spinal cord edema after intraoperative finding of highly infiltrative lesions making fine surgical manipulations potentially fearful. In these circumstances, usually a maintenance dose is also given for twenty three hours postoperatively. No cases showed any systemic complication of methyl prednisolone.

Intraoperative ultrasonography technology was utilized in nineteen cases (76%). It was especially helpful in lesions with cystic and solid components. In cases where spinal cord was not significantly distended by the tumor, it helped in accurate tumor localization, and with the aid of intraoperative neurophysiological monitoring, precise safest location of presumed myelotomy was determined. Also, ultrasonography was beneficial in real-time monitoring the extent of resection and assuring total excision in cases where good cleavage planes were found.

Intraoperative neurophysiological monitoring techniques were utilized in twenty cases (80%). Anal EMG was the only positive indicative parameter for intraoperative guidance in five cases. This highlights the importance and usefulness of utilizing anal EMG especially in lesions affecting the conus medullaris and cauda equina because it may be the only positive indicative parameter and thus, unnecessary postoperative deficits are avoidable.

In our experience, it is important to highlight the fact that postoperative hydrocephalus should be always suspected in all cases of cervical and cervicomedullary


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lesions whether the cisterna magna was opened or not. Urgent CT study of the brain should be asked for any patient with postoperative signs or symptoms of increased intracranial pressure or with significant wound collection or cerebrospinal fluid (CSF) leak. Three cases in this series had postoperative hydrocephalus as compared to preoperative baseline images. Ventriculo-peritoneal shunt systems were inserted for CSF diversion in those cases.

CONCLUSION

Management of pediatric spinal tumors is challenging. Our management strategy relies mainly on optimizing safe and maximal tumor excision in cases when there are clear cleavage planes and avoiding total excision in infiltrating tumors. Frozen section pathology is mandatory to decide further surgical attitude. Advanced surgical adjuncts are mandatory for safe and effective surgery of spinal tumors especially intraoperative neurophysiological monitoring and ultrasonography. Anal EMG is of special importance and should not be neglected. Tumor resection should always be controlled by intraoperative neuro-physiological monitoring.

REFERENCES 1. Austin GM, Grant FC. The diagnosis, treatment,

and prognosis of tumors affecting the spinal cord in children. J Neurosurg 13(6): 535–545, 1956.

2. Baten M, Vannucci RC. Intraspinal metastatic disease in childhood cancer. J Pediatr 90(2): 207–212, 1977.

3. Binning M, Klimo P, Gluf W, Goumnerova L. Spinal tumors in children. Neurosurg Clin N Am 18(4): 631–658, 2007.

4. Blaser S, Harwood-Nash D. Pediatric spinal neoplasms. Top Magn Reson Imaging 5(3): 190–202, 1993.

5. Bloomer CW, Ackerman A, Bhatia RG. Imaging for spine tumors and new applications. Top Magn Reson Imaging 17(2):69-87, 2006.

6. Cooper PR, Epstein F. Radical resection of intramedullary spinal cord tumors in adults. J Neurosurg 63(4):492– 499, 1985.

7. Cristante L, Herrmann HD. Surgical management of intramedullary spinal cord tumors: functional outcome and sources of morbidity. Neurosurgery 35(1):69–76, 1994.

8. DeSousa AL, Kalsbeck JE, Mealey J, Campbell RL, Hockey A. Intraspinal tumors in children. A review of 81 cases. J Neurosurg 51(4): 437–445, 1979.

9. Ferrante L, Mastronardi L, Celli P, Lunardi P, Acqui M, Fortuna A. Intramedullary spinal cord ependymomas – a study of 45 cases with long-term

follow-up. Acta Neurochir (Wien) 119(1-4):74–79, 1992.

10. Feyissa AM, Tummala S. Intraoperative neurophysiologic monitoring with Hoffmann reflex during thoracic spine surgery. J Clin Neurosci pii: S0967-5868(15)00026-0, 2015.

11. Goh KY, Velasquez L, Epstein FJ. Pediatric intramedullary spinal cord tumors: is surgery alone enough? Pediatr Neurosurg 27(1) :34–39, 1997.

12. Iwasaki Y, Hida K, Sawamura Y, Abe H. Spinal intramedullary ependymomas: surgical results and immunohistochemical analysis of tumour proliferation activity. Br J Neurosurg 14(4):331–336, 2000.

13. Khanna AJ, Shindle MK, Wasserman BA, Gokaslan ZL, Gonzales RA, Buchowski JM, Riley LH 3rd. Use of magnetic resonance imaging in differentiating compartmental location of spinal tumors. Am J Orthop (Belle Mead NJ) 34(10):472-6, 2005.

14. Lewis DW, Packer RJ, Raney B, Rak IW, Belasco J, Lange B. Incidence, presentation, and outcome of spinal cord disease in children with systemic cancer. Pediatrics 78(3):438–443, 1986.

15. Li F, Gorji R, Allott G, Modes K, Lunn R, Yang ZJ. The usefulness of intraoperative neurophysiological monitoring in cervical spine surgery: a retrospective analysis of 200 consecutive patients. J Neurosurg Anesthesiol 24(3):185-90, 2012.

16. Macbeth FR, Wheldon TE, Girling DJ, Stephens RJ, Machin D, Bleehen NM, Lamont A, Radstone DJ, Reed NS. Radiation myelopathy: estimates of risk in 1,048 patients in three randomized trials of palliative radiotherapy for non-small cell lung cancer. The Medical Research Council Lung Cancer Working Party. Clin Oncol (R Coll Radiol) 8(3):176–181, 1996.

17. McCormick PC, Stein BM. Intramedullary tumors in adults. In: Stein BM,McCormick PC (eds) Neurosurgery Clinics in North America. Volume 1, No. 3. Intradural Spinal Surgery. WB Saunders, Philadelphia, pp 609–630, 1990.

18. Morantz RA, Kepes JJ, Batnitzky S, Masterson BJ. Extraspinal ependymomas. Report of three cases. J Neurosurg 51(3):383–391, 1979.

19. Moser FG, Tuvia J, LaSalla P, Llana J. Ependymoma of the spinal nerve root: case report. Neurosurgery 31(5):962–964, 1992.

20. Nadkarni TD, Rekate HL. Pediatric intramedullary spinal cord tumors. Critical review of the literature. Childs Nerv Syst 15(1):17–28, 1999.

21. Prada F, Vetrano IG, Filippini A, Del Bene M, Perin A, Casali C, Legnani F, Saini M, DiMeco F. Intraoperative ultrasound in spinal tumor surgery. J Ultrasound 17(3):195-202. Collection 2014.

22. Raco A, Esposito V, Lenzi J, Piccirilli M, Delfini R, Cantore G. long-term follow-up of



70

intramedullary spinal cord tumors: a series of 202 cases. Neurosurgery 56(5):972–981, 2005.

23. Sandu N, Pöpperl G, Toubert ME, Spiriev T, Arasho B, Orabi M and Schaller B. Current Molecular Imaging of Spinal Tumors in Clinical Practice. Mol Med 17(3-4): 308–316, 2011.

24. Woltman HW, Kernohan JW, Adson AW, Craig WM. Intramedullary tumors of spinal cord and

gliomas of intradural portion of filumterminale. Fate of patients who have these tumors. Arch Neurol Psychiatr 65(3):378– 393, 1951.

25. Xu QW, Bao WM, Mao RL, Yang GY. Aggressive surgery for intramedullary tumor of cervical spinal cord. Surg Neurol 46(4):322–328, 1996.

Documents

Original Article Management of Pediatric Spinal Tumors · Pediatric tumors, Spinal tumors, Ependymoma, Astrocytoma, Neurophysiological monitoring Background: spinal tumors constitute