-Original-

Association of Pedicle Sign Type with Clinical and Radiological Features in Patients with Symptomatic Spinal Metastases

Yasuyuki Kitagawa, Yong Kim, Ryu Tsunoda and Shinro Takai

Department of Orthopedic Surgery, Nippon Medical School, Tokyo, Japan

Background: Because of population aging in Japan, the number of cancer diagnoses is increasing rapidly. The pedicle sign is a valuable radiographic indicator of metastases, as the pedicle is the most commonly affected vertebral structure in radiographic assessment. However, few studies have carefully examined the morphological features of pedicle signs. To improve the capacity of medical professionals to diagnose symptomatic spinal metastases, we retrospectively examined the morphological characteristics of pedicle signs and their associations with clinical and radiological features.
Methods: 186 patients with symptomatic spinal metastases who visited our department during the period from January 1, 2011 through December 31, 2017 were enrolled. The pedicle sign was defined as a missing or obscured pedicle on an anteroposterior radiograph. Radiographs were evaluated for pedicles and other vertebrae structures. Clinical and other radiological features were compared in relation to the type of pedicle sign identified.
Results: Pedicle signs were classified as completely disappeared (complete, 26 patients), partially disappeared (partial, 40 patients), or obscured by the osteoblastic background (blastic, 28 patients). Disappearance of both the bone cortex and pedicle was observed in almost half of the patients with complete or partial pedicle signs. The complete pedicle sign was associated with significantly longer survival.
Conclusion: Diagnosis of bone metastases requires understanding of pedicle sign types.

J Nippon Med Sch 2021; 88: 25-31

Keywords
pedicle sign, spinal metastases, classification, survival rate

Correspondence to
Yasuyuki Kitagawa, MD, Department of Orthopedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
kitayasu@nms.ac.jp

Received, October 2, 2019
Accepted, January 29, 2020