Inter-rater reliability between musculoskeletal radiologists and orthopedic surgeons on computed tomography imaging features of spinal metastases

Abstract

Introduction: The primary objective of this pilot study was to examine the inter-rater reliability in scoring the computed tomography (ct) imaging features of spinal metastases in patients referred for radiotherapy (rt) for bone pain.

Methods: In a retrospective review, 3 musculoskeletal radiologists and 2 orthopedic spinal surgeons independently evaluated ct imaging features for 41 patients with spinal metastases treated with rt in an outpatient radiation clinic from January 2007 to October 2008. The evaluation used spinal assessment criteria that had been developed in-house, with reference to osseous and soft tissue tumour extent,presence of a pathologic fracture,severity of vertebral height loss, andpresence of kyphosis.The Cohen kappa coefficient between the two specialties was calculated.

Results: Mean patient age was 69.2 years (30 men, 11 women). The mean total daily oral morphine equivalent was 73.4 mg. Treatment dose-fractionation schedules included 8 Gy/1 (n = 28), 20 Gy/5 (n = 12), and 20 Gy/8 (n = 1). Areas of moderate agreement in identifying the ct imaging appearance of spinal metastasis included extent of vertebral body involvement (κ = 0.48) and soft-tissue component (κ = 0.59). Areas of fair agreement included extent of pedicle involvement (κ = 0.28), extent of lamina involvement (κ = 0.35), and presence of pathologic fracture (κ = 0.20). Areas of poor agreement included nerve-root compression (κ = 0.14) and vertebral body height loss (κ = 0.19).

Conclusions: The range of agreement between musculoskeletal radiologists and orthopedic surgeons for most spinal assessment criteria is moderate to poor. A consensus for managing challenging vertebral injuries secondary to spinal metastases needs to be established so as to best triage patients to the most appropriate therapeutic modality.

Keywords: Computed tomography; inter-rater reliability; metastases; spine.

FIGURE 1

Cohen kappa coefficient for inter-rater agreement between musculoskeletal radiologists and orthopedic spinal surgeons on spinal metastases assessment criteria. R = right; L = left.