Percutaneous screw fixation of pelvic bone metastases using cone-beam computed tomography navigation

Purpose: The purpose of this study was to evaluate the efficacy of cone-beam computed tomography (CBCT) navigation to achieve percutaneous screw fixation (PSF) of pelvic bone metastases (PBM).

Materials and methods: Thirty-five consecutive patients (12 men and 23 women; mean age, 62 ± 11.3 [SD]; range: 39-89 years) treated between 2019 and 2021 were retrospectively included. CBCT navigation software was systematically used. Manual drawing of the entry point (MDEP) was performed when CBCT automatic positioning failed. Influence of metastasis pattern, ablation, body mass index, number of screws, and MDEP on procedure duration (PD) and total Air Kerma (AK) was evaluated. Local pain was assessed before, one and six months after treatment. Variables were compared using Pearson correlation, Student t and Wilcoxon tests.

Results: Seventy-five screws were inserted successfully (mean: 2.1 ± 1.1 [SD]; range: 1-5 per patient). CBCT automatic positioning was obtained for 41 screws (55%, 41/75), whereas 34 (45%, 34/75) required MDEP. Mean procedure duration, fluoroscopy time, kerma air product and AK were 73.3 ± 44.8 (SD) min (range: 19-233 min), 13.1 ± 9.5 (SD) min (range: 1.4-38.6 min), 73.8 ± 66.3 (SD) Gy.cm² (range: 11.6-303.7 Gy.cm²) and 301.7 ± 242.1 (SD) mGy (range: 49.4-1111.5 mGy), respectively. Procedure duration was not significantly longer in patients with mixed or blastic PBM compared to those with lytic PBM or when performing ablation, and no significant correlations were observed with the number of screws inserted (P = 0.19), MDEP (P = 0.37) and BMI (P = 0.44). No adverse events were reported during the follow-up (median: 6 months; IQR: 6-6.5 months). Thirteen patients died during the follow-up related to cancer progression. Local pain decreased from 35 ± 32 (SD) mm (range: 0-10 mm) to 11 ± 20 (SD) mm (range: 0-80 mm) at one month (P = 0.001); and to 22 ± 23 (SD) mm (range: 0-60 mm) at six months (P = 0.001).

Conclusion: CBCT navigation allows to effectively performing PSF of PBM even in the presence of steep angulations.