Comparison between Minimally Invasive Surgery and Conventional Open Surgery for Patients with Spinal Metastasis: A Prospective Propensity Score-Matched Study

STUDY DESIGN: Prospective Propensity Score-Matched Study OBJECTIVE.: To compare the outcomes of minimal invasive surgery (MIS) and conventional open surgery for spinal metastasis patients.

SUMMARY OF BACKGROUND DATA: There is lack of knowledge on whether minimally invasive surgery is comparable to conventional open surgery in treating spinal metastasis patients.

METHODS: Spinal metastasis patients requiring surgeries from January 2008 to December 2010 in two spine centers were recruited. The demographic, pre-operative, operative, peri-operative and post-operative data were collected and analyzed. Thirty MIS patients were matched with 30 Open Surgery patients using propensity score matching technique with a match tolerance of 0.02 based on the covariate age, tumor type, Tokuhashi score and Tomita score.

RESULTS: Both groups had significant improvements in ECOG, Karnofsky scores, VAS for pain and neurological status post-operatively. However the difference comparing the MIS and Open surgery group was not statistically significant. MIS group had significantly longer instrumented segments (5.5 ± 3.1) compared to open group (3.8 ± 1.7). Open group had significantly longer decompressed segment (1.8 ± 0.8) than MIS group (1.0 ± 1.0). Open group had significantly more blood loss (2062.1 ± 1148.0 mL) compared to MIS group (1156.0 ± 572.3 mL). More patients in the open group (76.7%) needed blood transfusions (with higher average units of blood transfused) compared to MIS group (40.0%). Fluoroscopy time was significantly longer in MIS group (116.1 ± 63.3 s) compared to open group (69.9 ± 42.6 s). Open group required longer hospitalization (21.1 ± 10.8 days) compared to MIS group (11.0 ± 5.0 days).

CONCLUSIONS: This study demonstrated that minimally invasive surgery resulted in comparable outcome to open surgery for patients with spinal metastasis but has the advantage of less blood loss, blood transfusions and shorter hospital stay.

LEVEL OF EVIDENCE: 3.