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Chapter Summary
• Context: Primary malignant bone tumors of the spine are rare entities characterized by distinct histological subtypes, biological behaviors, chemosensitivity profiles, and prognoses. The complex anatomy of the spine poses unique oncological challenges: intimacy with the spinal cord, nerve roots, major vascular trunks, and visceral structures severely restricts the surgical margins achievable without devastating functional sacrifice. Low-grade tumors (such as typical chondrosarcomas and chordomas) may grow insidiously to massive volumes before becoming symptomatic, whereas high-grade sarcomas (osteosarcoma, Ewing sarcoma) progress rapidly with intractable pain and spinal cord compression. An inaccurate initial diagnosis or an unplanned intralesional emergency decompression prior to staging and biopsy can permanently eliminate the opportunity for curative en bloc resection. The chapter applies the Enneking staging and Weinstein-Boriani-Biagini (WBB) surgical classification systems to structure multidisciplinary care across Ewing sarcoma, osteosarcoma, chondrosarcoma, and chordoma.
• Chapter Objective: To recognize clinical and radiographic hallmarks of primary spinal malignancy, execute rigorous pre-treatment staging and image-guided biopsy, apply the Enneking and WBB systems to surgical planning, and understand histology-specific protocols for en bloc resection, neoadjuvant/adjuvant chemotherapy, particle-beam/SBRT radiotherapy, and preoperative arterial embolization.
• Diagnosis and staging before interventionRadiographs offer limited sensitivity; CT characterizes cortical bone destruction and mineralized matrix; MRI delineates extraosseous soft-tissue extension, spinal cord effacement, and thecal sac relationship. Suspected malignancy requires full systemic staging (chest CT, PET-CT) and histological confirmation via image-guided percutaneous biopsy. The biopsy tract must be strategically planned so it can be resected en bloc with the surgical specimen.
• Enneking and WBB surgical stagingThe Enneking system classifies lesions by biological grade (IA, IB, IIA, IIB, III). The WBB classification (Figure 54.2) maps the transverse vertebra into 12 radial zones and 5 concentric tissue layers, defining tumor boundaries and guiding whether a total en bloc spondylectomy (TES), sagittal resection, or vertebrectomy can achieve wide, contamination-free oncological margins.
• Multidisciplinary treatment strategiesIn chemosensitive sarcomas (Ewing sarcoma, osteosarcoma), neoadjuvant systemic therapy shrinks tumor volume, treats micrometastatic disease, and provides prognostic histological response data (Figure 54.3). Hypervascular tumors benefit from preoperative arterial embolization (Figure 54.4). Palliative interventions aim to preserve ambulation and relieve pain when wide oncological margins are unattainable.
• Specific tumor histologiesEwing sarcoma requires multimodal systemic chemotherapy combined with surgical resection or targeted radiotherapy. Osteosarcoma mandates multi-agent neoadjuvant chemotherapy and wide-margin en bloc resection. Chondrosarcoma is notoriously resistant to chemotherapy and standard radiation, making negative-margin en bloc resection the primary determinant of cure (Figure 54.6). Chordoma is a slow-growing, locally invasive notochordal tumor with high recurrence rates, requiring wide en bloc sacrectomy/spondylectomy or high-dose proton/carbon ion radiation (Figure 54.7).
• Technological frontiers3D-printed custom titanium implants, computer navigation, surgical robotics, circulating tumor DNA (ctDNA) liquid biopsy, and molecular targeted therapies (e.g., IDH1 inhibitors in chondrosarcoma, EGFR/PDGFR inhibitors in chordoma) represent active evolutions in personalized care.
• Clinical Application: In clinical practice, the most vital rule is preventing apparent surgical urgency from compromising definitive oncological cure. Except in acute deteriorating paralysis with unconfirmed histology, systemic staging and image-guided percutaneous biopsy must precede surgical intervention. In chemoresponsive Ewing sarcoma or osteosarcoma, neoadjuvant chemotherapy should be administered first to induce tumor necrosis and shrink soft-tissue components. In chondrosarcoma and chordoma, the surgeon must plan a wide en bloc resection (total en bloc spondylectomy or sacrectomy) based on WBB zones, avoiding intralesional tumor violation which leads to catastrophic local recurrence. If wide margins would require sacrificing non-expendable spinal cord levels, high-dose proton-beam or carbon-ion radiotherapy combined with separation surgery is considered.
