This paper develops the Spine Instability Neoplastic Score (SINS), a six-component tool to grade instability in patients with spinal tumors. It was built by the Spine Oncology Study Group using systematic review and a modified Delphi consensus of 24 fellowship-trained spine surgeons. It answers a practical question: which patients with spinal metastases need surgical referral for instability?
When you see a patient with spinal metastases, calculate the SINS from the CT and history. A score of 7 or above means refer to spine surgery, whether you are the oncologist, radiologist, or emergency physician seeing them first.
Before SINS, no validated criteria existed for neoplastic instability. Clinicians borrowed traumatic instability classifications, which the authors reject: tumors follow different anatomic patterns, the spine cannot heal under active malignancy, and pathologic fractures behave differently than trauma.
Pay particular attention to mechanical pain (better lying down, worse with movement). This is the one clinical parameter in the score and signals true load-dependent structural failure that imaging alone will not capture.
SINS does not replace judgment. Neurologic deficit, prior laminectomy, multilevel disease, and prior radiation all modify surgical urgency independent of the score. SINS operationalizes the mechanical instability component of the broader NOMS framework.
This paper develops the Spine Instability Neoplastic Score (SINS), a six-component tool to grade instability in patients with spinal tumors. It was built by the Spine Oncology Study Group using systematic review and a modified Delphi consensus of 24 fellowship-trained spine surgeons. It answers a practical question: which patients with spinal metastases need surgical referral for instability?
When you see a patient with spinal metastases, calculate the SINS from the CT and history. A score of 7 or above means refer to spine surgery, whether you are the oncologist, radiologist, or emergency physician seeing them first.
Before SINS, no validated criteria existed for neoplastic instability. Clinicians borrowed traumatic instability classifications, which the authors reject: tumors follow different anatomic patterns, the spine cannot heal under active malignancy, and pathologic fractures behave differently than trauma.
Pay particular attention to mechanical pain (better lying down, worse with movement). This is the one clinical parameter in the score and signals true load-dependent structural failure that imaging alone will not capture.
SINS does not replace judgment. Neurologic deficit, prior laminectomy, multilevel disease, and prior radiation all modify surgical urgency independent of the score. SINS operationalizes the mechanical instability component of the broader NOMS framework.