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

Abstract

Background: Cancer diagnoses are increasing rapidly due to the aging population of Japan. Pedicle sign is a valuable radiographic indicator of metastases as the pedicle is the most commonly affected part of the vertebra upon radiographic assessment. However, few detailed studies examining the morphological features of pedicle signs have been performed. To improve the capacity of medical professionals to diagnose symptomatic spinal metastases, we retrospectively examined the morphological characteristics of pedicle signs and their relationship with clinical and radiological features. Methods: In total, 186 patients with symptomatic spinal metastases who visited our department between January 1, 2011, and December 31, 2017, were enrolled in the study. Pedicle sign was defined as a pedicle that had disappeared or had become obscured on an anteroposterior radiographic image. Radiographic images were evaluated for pedicles and other structures of the vertebrae. Clinical and other radiological features were compared among the types of pedicle signs identified. Results: Pedicle signs were classified according to whether they had completely disappeared (complete type, 26 patients), partially disappeared (partial type, 40 patients), or were obscured by the osteoblastic background (blastic type, 28 patients). The disappearance of the bone cortex in addition to the pedicle was observed in almost half of the patients with complete and partial types of pedicle signs. Complete types were associated with significantly longer survival rates. Conclusion: Understanding of the various types of pedicle sign is required to properly diagnose bone metastases.

Spinal Metastases without Pedicle Signs on Radiograph and their Associated Clinical and Radiological Features

“…The first half of this study has already been reported for patients with a positive pedicle sign 5 . This report is the second half of the study, examined patients with negative pedicle signs.…”

“…The clinical characteristics of the BCP and BCN groups are summarized in Tables 1 and 2. Primary cancer sites included the lung (24), prostate (5), kidney (3), breast (4), digestive system (9), hematopoietic system (11), and others (8). The sites evaluated included 3 cervical, 24 thoracic, and 37 lumbar vertebrae.…”

“…Based on the results of the previous study on pedicle signs 5 and the results of this study on cases without pedicle signs, we propose a diagnostic protocol for painful spinal metastases on daily practice (Fig. 7).…”

“…First, the presence or absence of the pedicle sign is evaluated. At that time, it is necessary to recognize that there are complete type, partial type, and osteoblastic type in the pedicle sign 5 . In the absence of pedicle signs, cortical bone disappearance of other parts of vertebrae, increased radiolucency of central area in vertebral body, irregular osteoblastic change, and asymmetrical vertebral collapse of 5 degrees or higher are assessed.…”

“…The pedicle sign is a well-known and valuable radiographic indicator of bone metastases 3,4 . A recent investigation revealed the morphological features of the pedicle sign and reported various morphologies 5 . In the present study, we retrospectively investigated the radiological features of symptomatic spinal metastases in patients without the pedicle sign.…”