Clinicopathological Study of Intradural Extramedullary Spinal Tumors and Its Correlation With Functional Outcome

Abstract

Introduction Intradural extramedullary (IDEM) spinal cord tumors account for approximately two-thirds of largely benign intraspinal neoplasms. These are amenable to gross total excision and usually carry a good functional outcome. Methods In this study, we reviewed the surgical outcomes of 35 patients who underwent excision of intradural extramedullary tumors. Patient demographics, severity and duration of symptoms, and tumor characteristics (anatomical and pathological) in all operated spinal IDEM tumors were collected. The neurological findings obtained during the preoperative stage and the postoperative follow-up were evaluated according to the Frankel and Nurick grading. The back pain was assessed with help of the Denis pain scale (DPS). Results The histopathological outcomes of the study were as follows: six patients of neurofibroma, 12 cases of schwannoma, nine cases of meningiomas, three cases of ependymoma, one case of dorsal neurenteric cyst, two cases of epidermoid cyst, one case of cauda equina paraganglioma, and one case of filum terminale dermoid cyst. Paresthesia/numbness were the commonest symptoms (88.6%), weakness of limbs in (80%), sphincter dysfunction in 15 patients (42.9%), and paraplegia was seen in three patients (8.57%). The complications encountered were - one case each of cerebrospinal fluid (CSF) leak, surgical site infection, and pseudomeningocele. The percentage of spinal canal occupied ranged from 71-94%. The mean percentage of the spinal canal occupied by the tumor was 81.8%. In our series, 77.14% of patients (p<0.0001) had good functional outcomes as per improvement in Frankel score. The DPS and Nurick score mean values showed a significant decrease over the follow-up duration as compared to preoperative mean values. Significant functional improvement was noted at the one-week, one-month, and one-year follow-up, with a p-value of <0.0001. Conclusions The IDEM tumors are usually benign and are readily detected by contrast-enhanced MRI scans. These have excellent surgical outcomes with some exceptions. Greater canal occupancy and a longer duration of symptoms are usually seen to correspond with suboptimal functional outcomes.

Keywords: denis pain scale; frankel grade; functional outcome; intradural extramedullary spine tumors; nurick grade.

Figure 1. Percentage of tumor occupying intradural space was calculated with the formula {(a+b)/(A+B)} x 100

Transverse diameter of the tumor mass (a) + Longitudinal diameter of the tumor mass (b) / Transverse diameter of the intradural space (A) + Longitudinal diameter of the intradural space (B) x 100.

Figure 2. Patients' presenting symptoms

Figure 3. Axial tumor distribution

Figure 4. Pathological tumor types

Figure 5. Cervical neurofibroma

A: Contrast-enhanced sagittal MRI cervical spine with tumor. B: Intraoperative image with laminectomy done and tumor being dissected. C: Tumor specimen.

Figure 6. Lumbar spine ependymoma

A: MRI post-contrast image, sagittal section with tumor having patchy peripheral enhancement. B: MRI post-contrast image, axial cross-section. C: Intraoperative image. D: Tumor specimen.

Figure 7. Lumbar epidermoid cyst

A: MRI lumbosacral spine sagittal image with hypointense tumor mass on post contrast image. B: MRI lumbosacral spine with restriction on Apparent Diffusion Coefficient sequence. C: Diffusion-weighted image showing restriction. D: Intraoperative pearly white appearance of the cyst.

Figure 8. Paraganglioma of cauda equina region

A: MRI T2-weighted sagittal image with hypo intense lesion. B: Cauda equina paraganglioma sample after excision. C: Strong synaptophysin expression in tumor cells.

Figure 9. Filum terminale dermoid cyst

A: MRI T2-weighted sagittal image with iso- to hypointense image. B: Intraoperative image. C: Tumor specimen with stratified keratin and hair.

Figure 10. Postoperative Denis pain scale

The mean values of Denis pain scale show a significant decrease at one week, one month, and one year postoperative interval.