Introduction: Separation surgery describes a technique of surgical resection of metastatic spine tumors with decompression of neurologic structures combined with adjuvant radiation for local control. The extent of facet removal depends on the degree of disease. Bilateral facetectomy is considered the standard of care in separation surgery to achieve decompression. There is a lack of evidence supporting indications for unilateral vs. bilateral facetectomy in separation surgery. We present our experience utilizing unilateral facetectomy and describe operative characteristics related to this technique.
Methods: Patients who underwent spine surgery between 2022 and 2024 for metastatic disease were separated into cohorts by type of separation technique, unilateral or bilateral facetectomy. Retrospective chart review was performed collecting demographic, operative, and treatment data. Statistics was performed using SPSS software (V29.0).
Results: A total of 56 patients met inclusion criteria with 25 undergoing unilateral facetectomy (UF) and 31 undergoing bilateral facetectomy (BF). There was no significant difference in demographic variables between cohorts including age, gender, pre-operative Bilsky grade, and Spinal Instability Neoplastic Scale (SINS) Score. The UF group had more frequent unilateral posterior involvement of the tumor per the SINS classification. There was no significant difference in estimated blood loss, length of stay, post operative hardware failure. Change in pre-operative hemoglobin (Hb) (mg/dL) to immediate post-operative Hb was significantly less in the UF group (mean=-0.672±2.18), compared to the BF group (mean=-1.87±1.41), p=0.018. Kaplan Meier Analysis demonstrated no significant difference in survival between cohorts (p=0.06).
Conclusion : Utilizing UF for patients with unilateral posterior tumor involvement is safe and feasible for tumor resection with minimal differences in operative characteristics and improved Hb drop. Further work is needed to analyze long-term outcomes and tumor control from this technique.
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