General Session: Tumor, Trauma, and Infection

Presented by: N. Kumar - View Audio/Video Presentation (Members Only)

Author(s):

N. Kumar(1), B. Tan(1), A.S. Zaw(1)

(1) National University Health System, Singapore, Singapore

Abstract

Introduction/

Background: The spine is the prime target organ in the skeletal system as a metastatic site for the majority of primary tumours of epithelial origin. Surgery has an established role in management of metastatic spine disease(MSD). Spinal oncologic surgeries aimed at decompression and stabilization of the neural and osseous elements respectively remains an integral part in maintaining the quality of life in the terminal years of these patients. Due to the vast spectrum of patterns and severity of spinal metastases, a multitude of surgical techniques are employed. In analyzing variables influencing surgical outcomes, comparing data between institutions, and weighing clinical options of treatment, a standardized scoring system that compares the extent of surgery with outcome variables will be useful for surgeons and patients alike in both research and treatment planning.

Methods: Surgery for MSD can include anterior, posterior or combined approaches to the spinal column. We devised a metastatic spine surgery scoring system based on surgical intrusion of the vertebral column. The score is based on number of vertebrae instrumented posteriorly or anteriorly, the number of levels decompressed by posterior approach, extent of anterior decompression dictated by total/partial corpectomy, posterior fusion and vertebroplasty. The adjoining table represents the scores allocated to the above described surgical intrusion modalities (Table-1). The index was validated by the retrospective analysis of patients undergoing metastatic spinal surgery from 2005-2014. Data collected included patient demographics, type of primary tumour, type and extent of surgery, blood loss and transfusion, surgical duration and complications. The relationship between the intrusion score and outcome measures such as blood loss, blood transfusion, operative time and post-operative complications were analyzed.
TABLE 1
Posterior Instrumentation Per Vertebral Level - 1 score
Anterior Instrumentation Per Vertebral Level - 1 score
Posterior decompression Per Vertebral Level -1 score
Partial Corpectomy without cement/graft/cage per Vertebral Level -1 score
Partial Corpectomy with cement/graft/cage per Vertebral Level -2 scores
Total Corpectomy per Vertebral Level -4 scores
Posterior Fusion Per Vertebral Level -1 score
Vertebroplasty -1 score

Results: A total of 241 patients were included in the analysis. The median age was 60years (range:25-87) with gender distribution of 127 males(53%) and 114 females(47%). The median score of Intrusiveness Index was 7(range:1-20). Multivariate analyses revealed that the Intrusiveness Index score was independently associated with increased amount of blood loss, increased odds of blood transfusion and prolonged operative time after adjusting for a number of potential confounders. With every one score increase in Intrusiveness Index, there was a 42 ml increase in mean blood loss (95%CI:29-51, P=0.01), 10 minutes increase in mean operative time(95%CI:5-18, P=0.01) and 1.1 times increased odds of blood transfusion(95%CI:1.05-1.19, P=0.03). There was a tendency towards increased odds of developing postoperative complications with an increase Intrusiveness Index score in but this was not significant(OR=1.06, 95%CI:0.91-1.23, P=0.08).

Conclusion: This novel Intrusiveness Index correlates well with surgical outcomes, in particular with blood loss, transfusion requirements and operative time. We believe that it will have significant utility in clinical practice for clinical decision making and predicting risks and potential complications. In addition, this index would facilitate research by allowing fair comparisons between different types of operative procedures and operative outcomes between institutions.