Definition: Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
Input: Abstract: Lesions in the pedicles of the cervical spine are both a diagnostic and technical challenge. An osteoid osteoma of the pedicle of the fourth cervical vertebra occurred in a 17-year-old girl. Resection of the tumor adjacent to the dura medially and the vertebral artery anterolaterally was accomplished via a transpillar approach. The transosseus approach preserved the facet joints and posterior elements and obviated the need for an interbody fusion.

Spinal Neoplasms