METHODS: Patients who underwent BKP for VCFs with PVBW defects were compared with patients who underwent BKP for VCFs with no PVBW defects. Outcomes were assessed preoperatively and at 3 months. RESULTS: In the PVBW defect group, mean pain score decreased from 7.5 to 3.6 (p<.001), EQ5D increased from 0.39 to 0.48 and Oswestry Disability Index (ODI) decreased from 50 to 42. Cement leaks occurred in 31%. In the PVBW intact group, mean pain score decreased from 7.3 to 3.3 (p<.001), EQ5D increased from 0.35 to 0.48 (p<.001), and ODI decreased from 53 to 50. Cement leaks occurred in 20%. No significant difference was observed in functional improvements between groups. Radiographically kyphotic angle and anteri- or and middle vertebral body heights were significantly worse in the PVBW defect group (p<.05). There were no neurological deficits in either group. CONCLUSIONS: BKP can alleviate pain and improve QoL and function in patients with cancer-related VCFs and PVBW defects with no apprecia- ble increase in risk. CONFLICTS OF INTEREST: None. FUNDING SOURCES: None. http://dx.doi.org/10.1016/j.spinee.2016.12.052 45. Metastatic spinal cord compression due to unknown primary tumour: 5 year experience from a university teaching hospital Sujay Dheerendra, Shreya Srinivas, Mark McGowan, Antonino Russo, Radu Popa, Sathya Thambiraj, Prokopis Annis, Marcus deMatas; Royal Liverpool University Hospital, Prescot Street, Liverpool L7 8XP BACKGROUND CONTEXT: Metastatic Spinal Cord Compression (MSCC) due to unknown primary tumour (UPT) poses challenges in diagnosis and appropriate management. PURPOSE: The aim of our study was to assess the neurological and func- tional outcomes including survival compared to MSCC due to known primary tumours (KPT). STUDY DESIGN/SETTING: Prospective study. PATIENT SAMPLE: Patients diagnosed with MSCC. OUTCOME MEASURES: Frankel, Barthel, VAS & length of survival. METHODS: The data was collected prospectively between September 2010 and September 2015. RESULTS: There were 131 patients treated with MSCC during this period and 25 (19%) were due to UPT (M: F=15:10, mean age of 65 (42–81) years). 10 (40%) patients were treated with surgical intervention and 13 (52%) with radiotherapy. The median Tokuhashi score was 8 for surgery group and 7 for radiotherapy group (p<.05). The median time to obtain an MRI scan from referral was 18.04 hrs with only 1 (4%) breaching the 24-hour target. The Frankel score improved in 85% of the patients who underwent surgery com- pared to 90% in the KPT. The mean survival for UPT group was 156.5 days (Surgery: 160.2, Radiotherapy: 154; p=.9) compared to KPT group of 126.7 days (p=.24). The primary was confirmed in 15 (60%) patients [Lym- phoma (3), Lung (5), GI (5), Thyroid (1), Myeloma (1)]. CONCLUSIONS: The neurological outcomes and mean survival were similar in both the UPT and KPT groups. Interestingly there were no differences in survival or neurological outcome in patients who underwent surgery or radiotherapy in the UPT group. These patients present a conundrum in decision-making and our data would suggest a similar outcome on stan- dardizing management for every MSCC. CONFLICTS OF INTEREST: None. FUNDING SOURCES: None. http://dx.doi.org/10.1016/j.spinee.2016.12.053 46. The influence of histologic subtype in predicting survival of lung cancer patients with spinal metastases Jonathan Tan, KimberlyAnne Tan, Aye Sandar Zaw, Dennis Hey, Aravind Kumar, Naresh Kumar; University Spine Centre, National University Hospital of Singapore, 1E Kent Ridge Rd, NUHS Tower Block, Level 11, Singapore 119228 BACKGROUND CONTEXT: Recent Advancements in systemic treat- ment of lung cancer have significantly improved the survival of patients with certain histolopathologic and molecular subtypes. Existing prognostic scores do not account for this and patients with lung cancer spinal metastases are grouped together as poor prognostic candidates. Consequently, some may inappropriately be denied palliative spine surgery. PURPOSE: To study whether the expected survival in patients with lung cancer spinal metastases is affected by histolopathologic and molecular sub- types based on modern systemic therapy. STUDY DESIGN/SETTING: Retrospective review. PATIENT SAMPLE: 180 Patients. OUTCOME MEASURES: Karnofsky performance scores, predicted and actual survival. METHODS: We reviewed all patients with histologically confirmed lung cancer treated for spinal metastases at our institution between 2001 and 2012. Patients’ demographics, histopathologic details, treatment modali- ties, and survival data were collected. The primary outcome was survival from time of spinal metastases diagnosis. The Cox regression analysis was used to evaluate the influence of tumor histology, molecular profile and treatment modality on survival. The Kaplan-Meier survival analysis was conducted to compare lung cancer subtypes, as well as various treatment regimens. RESULTS: Out of 180 patients, 51 underwent surgery for spinal metasta- ses. Female sex (p=.019), absence of palsy (p=.023), good Karnofsky performance scores (p<.001), and non-small cell lung cancer (NSCLC) (p=.002) were favorable prognostic factors. Patients who received system- ic therapy, including tyrosine kinase inhibitors, platinum doublet chemotherapy, or both showed increased survival (p<.01). The median survival time was 2.40 months [95% confidence interval (CI), 2.13–2.68] in the small cell lung cancer cohort, with no patients surviving past a year; 5.10 months (95% CI, 3.78–6.41) in the NSCLC cohort, with 25.9% 1-year survival; and 13.3 months (95% CI, 2.26–24.40) in adenocarcinoma patients who received both tyrosine kinase inhibitors and platinum doublet therapy, with 50.0% 1-year survival. CONCLUSIONS: NSCLC, systemic therapy, female sex, absence of palsy and good Karnofsky performance scores are all independent favorable prog- nostic factors for patients with lung cancer spinal metastases. These should be routinely considered during prognostication. CONFLICTS OF INTEREST: None. FUNDING SOURCES: None. http://dx.doi.org/10.1016/j.spinee.2016.12.054 47. Metastatic spine tumour surgery: does perioperative blood transfusion influence postoperative complications? Aye Sandar Zaw, Dhiraj Sonawane, Karthikeyan Maharanjan, Dennis Hey, Aravind Kumar, Naresh Kumar; University Spine Centre, National University Hospital of Singapore, 1E Kent Ridge Rd, NUHS Tower Block, Level 11, Singapore 119228 BACKGROUND CONTEXT: Literature has raised the controversy re- garding the adverse effects of ABT influencing survival and/or postoperative complications. PURPOSE: To evaluate the influence of perioperative ABT on postopera- tive complications and infections in patients undergoing metastatic spinal tumour surgery (MSTS). STUDY DESIGN/SETTING: This is a retrospective cohort study includ- ing 10-year data in a tertiary university hospital. PATIENT SAMPLE: A total of 247 patients who underwent MSTS. OUTCOME MEASURES: Postoperative complications like systemic com- plication, electrolyte imbalance within 30 days after MSTS and Postoperative infections. METHODS: Variables recorded from electronic records and case notes in- cluded patient demographics, tumour characteristics, operative details and postoperative complications. Multivariate logistic regression analyses were S17 BASS 2017 abstracts / The Spine Journal 17 (2017) S3–S22 Refer to onsite annual meeting presentations and postmeeting proceedings for possible referenced figures and tables.Authors are responsible for accurately reporting disclosure and FDA device/drug status at time of abstract submission.