Decision Tree Machine Learning Identifies Unique Sub-populations Benefiting from Earlier Surgical Intervention in Acute Metastatic Spinal Cord Compression

Introduction: Neurologic decline from spinal cord compression is a frequent complication of spinal metastatic disease. Urgent surgical decision making is critical to preserve spinal cord function.

Methods: 125 patients were retrospectively reviewed (median follow-up 31.25 months). All patients underwent surgical decompression for spinal metastatic disease with epidural spinal cord compression (Bilsky grade > 1). Functional status was assessed using Karnofsky Performance Score (KPS) and American Spinal Injury Association Impairment scale (AIS). Recursive partitioning analysis (RPA) was used for regression.

Results: 125 patients were reviewed. AIS E patients (n=21) who underwent surgery within 89.5 hours of admission preserved their deficit-free status (n=13), and AIS E patients that had surgery after 89.5 hours (n=8) declined by a mean of 0.24 AIS grades at discharge. AIS D (n=69) patients improved by a mean of 0.41 AIS grades when surgery was done within 92.25 hours (n=49), and there was no mean improvement for 20 patients after this time point (p=0.038). AIS B/C (n=35) patients with low functional status (KPS ≤ 45) had a mean AIS grade increase of 1.1 when surgery occurred within 62 hours (n=16) and a mean increase of 0.42 AIS grades after 62 hours (n=19) (p=0.015). Patients with KPS 65-75 improved by a mean of 5.6 KPS points when surgery was performed within 82 hours of presentation (n=16) but declined by mean 2.2 points when surgery was done 82 hours after admission (n=9) (p=0.016).

Conclusion : Timing of surgical intervention is a key determinant of neurologic and functional status preservation and recovery in metastatic spinal cord compression. AIS B/C patients with KPS ≤ 45 benefited from an earlier surgical timepoint (62.5 hours) than AIS E (89.5 hours) and D patients (92.25) at all KPS. Leveraging machine learning methods in future studies can further stratify high-risk patient populations to optimize timing of surgery.