Measuring the paraspinal muscles as an important tool for predicting the overall survival period after spine surgery in lung cancer patients with spine metastasis.

STUDY DESIGN: Retrospective cohort study BACKGROUND: Metastatic lung cancer in the spine is difficult to determine whether to perform an additional surgical intervention, as patients at the end stage of lung cancer often have low performance status with significant muscle atrophy. This study aimed to demonstrate whether sarcopenia affects the prognosis after spine surgery in lung cancer patients by measuring the paraspinal muscles.

METHODS: A total of 65 lung cancer patients who underwent spine surgery were reviewed. Patients were divided into two groups based on the survival period after surgery (≤ 6 months; n = 33 and > 6 months; n = 32). Based on magnetic resonance imaging, the quantity and quality of the paraspinal muscles (psoas major, quadratus lumborum, erector spinae, and multifidus) were analyzed by an Image J program. Patient- and surgery-related factors were compared between the two groups.

RESULTS: The quantity of the erector spinae muscle was higher in the > 6 months group (11.5 ± 2.8 cm2/m2) than in the ≤ 6 months group (10.0 ± 2.3 cm2/m2, p = 0.013). The logistic regression analysis showed that the muscle quantity of the erector spinae (p = 0.026, odds ratio 1.343) and the number of vertebrae involved in metastasis (p = 0.016, odds ratio 0.199) were the main prognostic factors for the survival period after spine surgery.

CONCLUSIONS: Lung cancer patients with a low quantity of the erector spinae muscles are at a high risk of poor prognosis after spine surgery. Therefore, measuring the erector spinae muscle could be an important tool for distinguishing patients appropriate for palliative treatments and surgical interventions.