Suggested Criteria regarding Effectivity of a Posterior Approach for Intradural Extramedullary Spinal Tumors

Abstract

Introduction Intradural extramedullary spinal tumors are uncommon, with a reported incidence 3 to 10 per 100,000 people, the majority of these lesions are benign (WHO grades I and II) and that are treated by posterior approach with conventional laminectomy. However, there are some factors that influence the surgical success of these tumors, which if not taken into account may change the prognostic patient. We have investigated what are these factors and their influence on surgical outcomes. Patients and Methods We performed a retrospective review of 31 consecutive patients, who presented with intradural extramedullary spinal tumors that was removed by posterior approach with conventional laminectomy between January 2011 and May 2014, the neurological findings obtained during the preoperative stage, and the postoperative follow-up were evaluated according to the Nurick grade with a minimum follow-up time of 6 months. The axial and sagittal anatomical location, the tumor occupancy rate, and tumor extension (evaluated in MRI), as well as histopathological diagnosis, tumor–cord interface, age, and sex were analyzed in relation to the postoperative neurological status (assessed by Nurick grade). Results The group was predominantly female with a ratio female:male, 4.2:1; with a mean 49.5 years (range, 16–85 years). The most common histologic diagnoses were schwannoma and meningioma, with a ratio 1.7:1. Of all the patients, in 64.5% of patients tumor–cord interface was found. The mean tumor occupancy rate was 66.3% ± 16.9. The postoperative neurological status is positively related with the following: age, female sex, dorsolateral axial location, cervical and thoracic sagittal location, tumor occupancy rate, tumor extension three or more levels, tumor–cord interface, and histopathological diagnosis meningioma ( R = 0.776). Those with greater strength to explain the event of postoperative neurological status are as follows: age, tumor extension three or more levels, and cervical sagittal anatomical location ( p < 0.05). At the postoperative period, Nurick grade was improved from 3 ± 1.2 to 2.5 ± 1.8 [ T (31) = 2.590, p = 0.015]; and from 3 ± 1.2 to 1.7 ± 1.8 [ T (30) = 5.163, p < 0.01) at follow-up time of 6 months. Conclusion Intradural extramedullary tumors can be safely and effectively removed using posterior approach with conventional laminectomy, if it satisfies the following conditions. It has tumor–cord interface, histopathological diagnosis of meningioma, tumor < 3 segmental levels in extension, male sex, lower tumor occupancy rate, lower age, less cervical tumors, and less dorsolateral axial anatomical location.