Spinal schwannoma: Size has no correlation with presentation and outcome

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1 Spinal schwannoma: Size has no correlation with presentation and outcome Ravi Shankar Prasad*, Ruchi**, Kulwant Singh***, Ajit Singh**** *Assistant Professor, Department of Neurosurgery, Institute of Medical Sciences, BHU, Varanasi **Senior Lady Medical Officer, Deptt of Obstetrics & Gynecology, IMS, BHU ***Professor and Head, Department of Neurosurgery, IMS, BHU ****Associate Professor, Department of Orthopedics, IMS, BHU ABSTRACT Background: Solitary spinal nerve schwannomas or neurinomas are the most common nerve sheath tumors of the spine. Gold standard treatment for symptomatic spinal schwannomas is complete surgical resection. In this study we retrospectively review the results of surgically treated 30 cases of such schwannomas and find the variables associated with clinical presentation and final outcome. Material and Methods: This was a retrospective study included 30 patients of spinal schwannoma operated during May 2016 and February Demographic and functional outcome was assessed using the motor power grade and sensory changes. Result: Average age of presentation was 40.8 years (range years). Average longitudinal tumor size was 2.27cm. Patients were divided in two groups - First group with 20 (66.67%) patients with less than 2.3cm tumor length and second with patients more than 2.3 cm size had 10 (33.33%) patients. On comparison of age and tumor size, clinical presentation and functional outcomes no significant difference was found between both groups. Conclusion: Lumbosacral region accommodates larger schwannoma before it becomes symptomatic. There is no significant correlation between size of tumor and motor power and age of presentation. Surgery for spinal schwannomas usually result in good postoperative functional outcomes. Key words: spinal tumor, schwannoma, lumbosacral Introduction Solitary spinal nerve schwannomas or neurinomas are the most common nerve sheath tumors of the spine (1 4). Spinal schwannomas account for about 25% of intradural spinal cord tumors in adults (5-9). Most are solitary schwannomas, which can occur throughout the spinal canal (7). An equal distribution of male and female has been reported, although slight prevalence of males has been recently noted in one of the largest series (10); clinical presentation is most common during the fourth and fifth decades of life (11,12). These tumors typically arise from Schwann cells of a sensory nerve root; they appear as a globular, welldefined, encapsulated mass, well defined and separated from the other rootlets (13). Microscopically, schwannomas are characterized by high cellularity, and relative lack of an Antoni B pattern. The multiple form of neurofibromas is known as von Recklinghausen's disease (14). According to Western studies, the incidence of spinal schwannomas varies between cases/100,000 persons per year (8). Gold standard 742

2 treatment for symptomatic spinal schwannomas is complete surgical resection, which stops symptoms progression, helps recovery in most patients, and decreases the rate of recurrence. Materials and methods This was a retrospective study carried out in the department of neurosurgery, Institute of Medical Sciences, BHU. It includes 30 patients of spinal schwannoma admitted at our center during May 2016 and February The information was collected from medical records regarding age, sex, clinical presentation, tumor location, operative findings and post-operative complications. All cases were operated and the excised tumor specimen was confirmed in histopathology. Functional outcome was assessed using the motor power grade and sensory changes. Patients were called for follow up in OPD initially every month for 3 months then at six months intervals. Results There were total 30 patients out of which 14(46.67%) were male and 16(53.33%) were female. Average age of presentation was 40.8 years ranging from 24 to 60 years. Based on location we had 8(26.67%) cases of cervical, 14(46.67%) cases of dorsal and 8(26.67%) of lumbosacral schwannomas (Table 1). The average age of cervical lesions was years, dorsal lesions years, and lumbosacral lesions years. Average longitudinal tumor size was 2.27cm. Average tumor size of cervical tumor was 2.13cm, dorsal tumor was 2.14cm and lumbosacral tumor was 2.63cm (Table 2). Table 1: Tumor characteristics Characteristics No. of cases Mean age 40.8 years Sex Male Female 14(46.67%) 16(53.33%) Location Cervical Dorsal Lumbosacral 8(26.67%) 14(46.67%) 8(26.67%) 743

3 Table 2: Tumor location wise characteristics Location Average age (years) Average longitudinal size (cm) Cervical Dorsal Lumbosacral Patients presented with variety of symptoms and signs, the common presentations were localized pain (like cervical, dorsal or lumbar), radicular pain depending upon the root of origin, motor weakness, sensory loss, and loss of bowel and bladder control. The frequency of these presentations are shown in table 3. Table 3: Common symptoms Symptoms No. of cases (%) Localized spinal pain 26 (86.67%) Radicular pain 26 (86.67%) Motor weakness 23 (76.67%) Loss of bowel and bladder control 17 (56.67%) The average duration of symptoms was 4.53 months ranging from 1 month to 1 year. The most common initial symptom was radicular pain followed by localized spinal pain then motor weakness and voiding difficulty. We had 28(93.33%) cases of intradural extramedullary lesions and 2(6.67%) cases of pure extradural tumors. All of the patients were operated, laminectomy was done. Complete excision was done in 27 (90%) cases but in 2 cases of cervical lesions part of tumor which was adherent to vertebral artery was left behind. In one case, tumor was encroaching into the thoracic cavity so only partial excision could be done. He was further managed by CTVS department. Histopathological confirmation was done postoperatively. At the time of discharge all of the patients appeared to be significantly improved in comparison with their preoperative neurological status. We divided the patients in two groups for various correlations. First group with 20 (66.67%) patients with less than 2.3cm tumor length and second with patients more than 2.3 cm size had 10 (33.33%) patients. On comparison of age and tumor size we did not find any correlation between (Table 4). 744

4 Table 4: Age and tumor size correlation Age group (years) Tumor < 2.3cm (n=20) Tumor 2.3cm (n=10) p-value On comparison of size of tumor and location of tumor it was found that larger tumors were significantly more common in lumbosacral region (Table 5). Table 5: Tumor location and size correlation Location of tumor Tumor < 2.3cm (n=20) Tumor 2.3cm (n=10) p-value Cervical Dorsal Lumbosacral We categorized our patients in two groups. Group 1 with motor power <3/5 and group 2 with power 3/5 below the level of tumor. There was tendency of smaller tumors not to affect the power much but the correlation was not found significant (Table 6). Table 6: Correlation between tumor size and grade of power in affected limbs Grade of power Tumor < 2.3cm (n=20) Tumor 2.3cm (n=10) p-value <3/ /

5 Discussion Spinal schwannomas account for about 25% of primary intradural spinal cord tumors in adults. Solitary or syndromic spinal nerve schwannomas are considered the most common primary spinal tumors (2,3,4,10,15). Many clinical and surgical series are reported in the literature, showing relatively uniform data about prevalence and incidence. Males and females are equally affected, and the age of onset is usually between 25 and 50 years (4,15). Hirano and colleagues reported an extended series of 678 spinal cord tumors, schwannomas were the most common histological type, with a slight prevalence of male sex (M : F = 1.3 : 1) and onset between 50 and 59 years of age (10). We also had almost equal sex distribution in our series with slight female preponderence. However in a study by jee et al somewhat higher prevalence in males (60.0%) was found (16). The incidence of schwannoma varies with the age of affected patients who are between the 4th and the 5th decade (17,18). In our study mean age of presentation was 40.8 years and maximum number of patients were between years age. However other age groups also had comparable figures. In the series by jee et al mean age was 50.2 years and peak incidence was also between the 4th and 5th decade (16). The tumor presents an ubiquitous evolution in the spine (8,18), even if a major incidence in the cervical and lumbar tracts is reported (7,8,18,19). In our study, the higher incidence was seen in the dorsal spine (46.6%). In the literature, 70 to 80% of spinal schwannomas are reported to be intradural in location, and those extending through the dural aperture as a dumbbell mass with both intradural and extradural components account for another 15% (20,21). Intramedullary schwannomas are extremely rare (5). We also had no case of intramedullary schwannoma in our series and we had only two cases of pure extradural tumors. Symptoms vary according to the level of the tumor. Pain is the commonest and the foremost complaint be it the localized spinal pain or the radicular pain. At the beginning the root pain is attributed to the disturbance of nerve conductivity because of the direct or indirect irritation of nerve root or root compression by the tumor (5,7). Later on when compression increases to spinal cord, spinal tracts gets damaged and myelopathy develops (22,23). However, motor weakness rarely occurs as an initial symptom in the lumbosacral region. Motor weakness of the lower extremity may not be obvious until the later stage, as in patients with lumbar canal stenosis. In our series also localized pain and the radicular pain were two common symptoms. Motor weakness was also common but more often a presentation of cervical or dorsal lesion. Loss of bowel and bladder control was seen in patients with tumors with any location. The average duration of symptoms in a study by Jee et al was 13.1 months ranging from 1 to 84 months (16). In our study it was 4.53 months ranging from 1 month to 1 year. This shorter duration in our patients was due to the fact that we are easily picking up the lesions due to easy availability of MRI and patient seeking medical advice earlier. Although total resection of spinal nerve sheath tumors has been considered to be feasible (22,23), some cases have resected incompletely (14,24). There may be two obstacles to total resection: one is adhesion to the spinal cord because of hemorrhage, inflammation, or subpial localization; the other is critical structures attached to extradural components outside the spinal canal in the cervical region, such as the vertebral artery. In our study, all of the patients were operated, laminectomy was done. Complete excision was done in 27 (90%) cases but in 2 cases of cervical lesions part of tumor which was adherent to vertebral artery 746

6 was left behind. In one case, tumor was encroaching into the thoracic cavity so only partial excision could be done. In case of residual tumor, a long-term observation is needed (20). Histopathological confirmation has to be done in all cases because sometimes meningiomas and malignant schwannoma can behave very similarily. At the time of discharge all of the patients appeared to be significantly improved in comparison with their preoperative neurological status. Jee et al also had 65% patients recovered and 30% improved (16). On comparison of age and tumor size we did not find any correlation between, neither in literature we could find any correlation. This means that even a young patient can have large tumors or elderly patient can present with small tumors. On comparison of size of tumor and location of tumor it was found that larger tumors were significantly more common in lumbosacral region. This may be due to the fact that this region contains only the roots which are displaced by the tumor rather than being compressed, and moreover there is enough CSF space in this region. In literature we could not find any correlation between location and tumor size. Larger tumors produced more symptoms specially the motor weakness and there was tendency of smaller tumors not to affect the power much but the correlation was not found significant. Neither in any of other studies is such association found. Conclusion Lumbosacral region accommodates larger schwannoma. There is no significant correlation between size of tumor and motor power grade, and age of presentation. Surgery for spinal schwannomas usually result in good postoperative functional outcomes. References 1- J. F. Annegers, B. S. Schoenberg, H. Okazaki, and L. T. Kurland, Epidemiologic study of primary intracranial neoplasms, Archives of Neurology, vol. 38, no. 4, pp , T. Jinnai, M. Hoshimaru, and T. Koyama, Clinical characteristics of spinal nerve sheath tumors: analysis of 149 cases, Neurosurgery, vol. 56, no. 3, pp , M. T. Seppala, M. J. J. Haltia, R. J. Sankila, J. E. Jaaskelainen, and O. Heiskanen, Long-term outcome after removal of spinal schwannoma: a clinicopathological study of 187 cases, Journal of Neurosurgery, vol. 83, no. 4, pp , P. Li, F. Zhao, J. Zhang et al., Clinical features of spinal schwannomas in 65 patients with schwannomatosis compared with 831 with solitary schwannomas and 102 with neurofibromatosis type 2: a retrospective study at a single institution, Journal of Neurosurgery Spine, vol. 24, no. 1, pp , Celli P, Trillo G, Ferrante L. Spinal extradural schwannoma. J Neurosurg Spine. 2005;2: De Verdelhan O, Haegelen C, Carsin-Nicol B, Riffaud L, Amlashi SF, Brassier G, et al. MR imaging features of spinal schwannomas and meningiomas. J Neuroradiol. 2005;32: Dorsi MJ, Belzberg AJ. Paraspinal nerve sheath tumors. Neurosurg Clin N Am. 2004;15: Seppala MT, Haltia MJ, Sankila RJ, Jaaskelainen JE, Heiskanen O. Long-term outcome after removal of spinal schwannoma : a clinicopathological study of 187 cases. J Neurosurg. 1995;83:

7 9- Sharma S, Sarkar C, Mathur M, Dinda AK, Roy S. Benign nerve sheath tumors : a light microscopic, electron microscopic and immunohistochemical study of 102 cases. Pathology. 1990;22: K. Hirano, S. Imagama, K. Sato et al., Primary spinal cord tumors: review of 678 surgically treated patients in Japan. A multicenter study, European Spine Journal, vol. 21, no. 10, pp , P. Conti, G. Pansini, H. Mouchaty, C. Capuano, and R. Conti, Spinal neurinomas: retrospective analysis and long-term outcome of 179 consecutively operated cases and review of the literature, Surgical Neurology, vol. 61, no. 1, pp , W. J. Levy, J. Latchaw, J. F. Hahn, B. Sawhny, J. Bay, and D. F. Dohn, Spinal neurofibromas: a report of 66 cases and a comparison with meningiomas, Neurosurgery, vol. 18, no. 3, pp , P. Banczerowski, R. Veres, and J. Vajda, Modified surgical approach to cervical neurinomas with intraforaminal components: minimal invasive facet joint sparing open-tunnel technique, Journal of Neurological Surgery, Part A: Central European Neurosurgery, vol. 75, no. 1, pp , Conti P, Pansini G, Mouchaty H, Capuano C, Conti R. Spinal neurinomas : retrospective analysis and long-term outcome of 179 consecutively operated cases and review of the literature. Surg Neurol.2004;61: discussion M. M. Safaee, R. Lyon, N. M. Barbaro et al., Neurological outcomes and surgical complications in 221 spinal nerve sheath tumors, Journal of Neurosurgery Spine, vol. 26, no. 1, pp , Jee Ho Jeon, Hyung Sik Hwang, Je Hoon Jeong, Se Hyuk Park, Jae Gon Moon, Chang Hyun Kim. Spinal Schwannoma; Analysis of 40 cases. J Korean Neurosurg Soc. 2008; 43: Klekamp J, Samii M. Surgery of spinal nerve sheath tumors with special reference to neurofibromatosis.neurosurgery. 1998;42: discussion Selosse P, Granieri U. [Spinal intradural meningiomas and neurinomas Review of the literature and current situation] Neurochirurgie. 1968;14: Miura T, Nakamura K, Tanaka H, Kawaguchi H, Takeshita K, Kurokawa T. Resection of cervical spinal neurinoma including affected nerve root : recovery of neurological deficit in 15 cases. Acta Orthop Scand. 1998;69: Jinnai T, Koyama T. Clinical characteristics of spinal nerve sheath tumors : analysis of 149 cases.neurosurgery. 2005;56: discussion McCormick PC, Post KD, Stein BM. Intradural extramedullary tumors in adults. Neurosurg Clin N Am.1990;1: Hori T, Takakura K, Sano K. Spinal neurinomas--clinical analysis of 45 surgical cases. Neurol Med Chir (Tokyo) 1984;24: Subaciute J. [Early diagnosis of spinal cord schwannoma : the significance of the pain syndrome]medicina (Kaunas) 2002;38: Lot G, George B. Cervical neuromas with extradural components : surgical management in a series of 57 patients. Neurosurgery. 1997;41: discussion

Spinal Schwannoma: scrutinizing the armamentarium of a single institute.

Spinal Schwannoma: scrutinizing the armamentarium of a single institute. Rami Alqroom MD*, Hussam Abu-nowar MD*, Dua`a Al Shurbaji MD**, Muath Alqurashi MD***, Wesam Khraisat MD****, Amer Al Shurbaji MD*