A needle-mounted guide for improving needle visualization during ultrasound-guided needle insertion: a simulation study in novice operators

Abstract Background In ultrasound-guided needle insertion, continuous needle visualization is crucial for accurate needle placement, particularly for beginners. Novice operators may have difficulty maintaining the spatial relationship between the needle trajectory and the ultrasound imaging plane during freehand needle insertion. To address this educational challenge, we developed a detachable flat plate that can be attached to the needle shaft as a visual and tactile reference to assist alignment with the ultrasound imaging plane. The present study aimed to evaluate this plate's potential utility as an educational aid for novices performing both in-plane and out-of-plane techniques. Methods This simulation-based randomized exploratory study included 32 practitioners who had no prior experience performing ultrasound-guided puncture. The participants were assigned to either the intervention group or the control group. In the intervention group, a custom-made flat plate was attached to the needle to assist alignment with the ultrasound imaging plane. After watching a brief video explaining how to do the procedure, the participants performed puncture tasks on a gelatin phantom at three probe positions—at the apex and at locations 45° to either side of the apex—using both in-plane and out-of-plane techniques. The primary endpoint was needle visualization during in-plane puncture at the right 45° position, assessed on a 5-point scale by a blinded evaluator. In addition, participants rated the ease of needle visualization using a 100-mm visual analogue scale. Results Of the 39 individuals assessed for eligibility, 32 were included in the analysis (16 in the control group and 16 in the intervention group). All participants were right-handed except for one left-handed individual in the control group. The distributions of sex and participant background (medical students or nurses) were comparable between the two groups. No significant difference in objective needle-visualization scores was observed between the intervention and control groups ( p = 0.0516), whereas self-assessed ease of needle visualization was significantly higher in the intervention group ( p = 0.0157). In subgroup analysis within the intervention group, angled in-plane puncture showed a tendency toward higher objective and subjective scores, with no such tendency observed for the out-of-plane technique. Conclusions Our needle-mounted guide improved subjective assessments of needle visualization and showed potential benefits during angled in-plane puncture. These findings suggest that the guide may help novice practitioners maintain alignment between the needle and the ultrasound imaging plane. Further evaluation in more homogeneous and standardized novice populations is required to assess the educational value and potential clinical applications of the device.