Treatment of extramedullary tumors: morbidity and long-term results

Surgery on extramedullary tumors has a place among the most gratifying operations in neurosurgery. However, little data exist on permanent morbidity and long-term results. This paper provides these data and analyzes which factors influence them and how they can be managed.

Among 2081 patients with tumors of the spinal canal presenting between 1991 and 2024, 605 patients were identified with intradural extramedullary tumors, of whom 500 patients underwent 570 operations. Multiple regression was used to identify factors influencing resection and morbidity rates. Short-term results were analyzed according to a neurological scoring system for individual symptoms, while long-term results were determined calculating recurrence-free outcome rates with Kaplan-Meier statistics.

The mean age for operated patients was 49.8 ± 18 years, presenting after a mean history of 21.2 ± 42 months. They were followed up by outpatient visits and questionnaires for up to 34 years (mean 43.3 ± 64 months). Overall, 87.4% of tumors were resected completely, while 11.2% underwent partial resection and 1.4% biopsy. Transient postoperative deteriorations were observed in 15.1% of surgeries. Permanent surgical morbidity occurred in 7.1%, that is, 4.8% for first surgeries and 18.4% for recurrent tumors (p < 0.0001). With complete resection, recurrence-free outcome rates of 80.5% and 77% after 5 and 10 years, respectively, were obtained, while partial resection reduced these rates to 40.0% and 36.4% after 5 and 10 years, respectively (p < 0.0001). Surgeons with > 100 operations achieved significantly higher recurrence-free outcome rates compared to surgeons with less experience at each postoperative time point. Schwannomas, meningiomas, ependymomas of the filum terminale, and hamartomas represented 89.8% of all pathologies and were analyzed separately. The best results for resection rates, permanent morbidity, and recurrence-free outcomes were observed for schwannomas. The highest morbidity rates were determined for ependymomas and hamartomas. Complete resection resulted in recurrence-free outcome rates of around 90% after 10 years for each histological group with the exception of meningiomas (73.3%).

Whenever an extramedullary tumor is completely resected, rates for surgical morbidity and 10-year recurrence-free outcomes are favorable. In contrast, with arachnoid adhesions, as in recurrent tumors and some hamartomas, complete resection rates decline, morbidity rates rise, and long-term results become less satisfactory. This emphasizes the importance of achieving complete resection, particularly in the first operation. Surgeons dedicated to spinal cord pathologies can expect to achieve superior long-term results.