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Updated: Apr 8, 2026
Three-Dimensional Printing Guide Template Assisted Percutaneous Vertebroplasty PVP
Published on: October 17, 2019
Lateral needle placement using 3D-printed ovoid-based needle guides mitigates the negative impact of high T-score
Santino Butler1, Thomas Niedermayr1, Elizabeth Kidd1
1Department of Radiation Oncology, Stanford University School of Medicine, Palo Alto, CA.
Background:
To aid brachytherapy needle placement for wide cervical tumors, we designed a three-dimensional-printed ovoid-based needle guide (OVI). This study aimed to evaluate dosimetric advantages with OVI and determine which patients may benefit most.
Methods:
This single-institution cohort study included 106 curative-intent cervical intracavity/interstitial brachytherapy implants (N = 95 OVI, N = 11 non-OVI) across 27 patients from 2020 to 2025. Predicted cumulative doses in 2-Gy-fraction-equivalents (EQD2) were calculated per implant, across needle-guide type and T-score (EMBRACE-validated prognostic tumor score).
Results:
Seventy percent received OVI for all implants (full-OVI); 30% received both OVI and non-OVI implants (partial-OVI)-with no significant differences in baseline features. Overall, 63% had FIGO stage III-IV disease, 70% had high-risk clinical target volume (HR-CTV) volume >30 cc (median, 38.3 cc), and 37% had high T-scores ≥10; mean HR-CTV width at cervical os was 5.1 cm. OVI (vs. non-OVI) implants achieved 9.1 GyEQD2 higher mean HR-CTV D90 (89.2 vs. 80.1 GyEQD2, p < 0.001) and were more likely to achieve target D90 > 85 GyEQD2 (86% vs. 18%; adjusted hazard ratio 11.4, p = 0.042)-with comparable mean D2cc to all normal tissues. Similar results were seen in "partial-OVI" subgroup. High T-score ≥10 was the most significant independent predictor for lower HR-CTV D90. There was a significant interaction between high T-score and needle guide type: T-score ≥10 tumors had an 8.4 GyEQD2 lower mean D90 with non-OVI implants but only a 2.1-GyEQD2 lower mean D90 with OVI implants (net +6.3 GyEQD2; pinteraction = 0.021).
Conclusions:
OVI enabled greater HR-CTV dose while maintaining similar dose to normal tissues. OVI particularly benefited high T-score tumors and made up for the HR-CTV D90 detriment seen in this group. These data demonstrate three-dimensional-printed tools as one additional method in facilitating needle placement for complex brachytherapy cases.
