https://orcid.org/0000-0002-6627-4165
Figures & data
Figure 1. Hazards in needle positioning. (a) Schematic of total needle geometry in patients with Pubic Arch Interference (PAI). The planned total needle geometry, indicated in the axial plane, is based on the needle geometry of Mate et al. [Citation11–13]. The pubic arch obstructs parts of the prostate resulting in a non-conformal total needle geometry, indicated by the light gray area in the sagittal plane, making accessible targets (X) inaccessible (O) using the transperineal approach with parallel horizontal needle trajectories (i.e. perpendicular to the transperineal template) using straight needle insertion. (b) Schematic of individual needle positioning errors in the prostate. The directions of the positioning error of the needle (red line) are shown in the axial and sagittal planes. The needle deviated from the neutral axis and did not reach the target (X).
![Figure 1. Hazards in needle positioning. (a) Schematic of total needle geometry in patients with Pubic Arch Interference (PAI). The planned total needle geometry, indicated in the axial plane, is based on the needle geometry of Mate et al. [Citation11–13]. The pubic arch obstructs parts of the prostate resulting in a non-conformal total needle geometry, indicated by the light gray area in the sagittal plane, making accessible targets (X) inaccessible (O) using the transperineal approach with parallel horizontal needle trajectories (i.e. perpendicular to the transperineal template) using straight needle insertion. (b) Schematic of individual needle positioning errors in the prostate. The directions of the positioning error of the needle (red line) are shown in the axial and sagittal planes. The needle deviated from the neutral axis and did not reach the target (X).](/cms/asset/3a1091bb-bfc6-4a59-aedd-af4e8803b9f2/ierd_a_2374761_f0001_oc.jpg)
Figure 2. PRISMA flow diagram of the literature selection method.
Table 1. Overview of studies that evaluated pubic arch interference (PAI).
Table 2. Overview of studies that evaluated needle misplacement in transperineal prostate interventions.
Table 3. Overview of studies that evaluated needle displacement in transperineal prostate interventions.
Figure 3. Decision-tree for conformity to treatment plan including clinical guidelines. Rounded rectangle shapes indicate procedural steps. Diamond shapes indicate the limits. Exceeding a limit (red diamond shape) requires a solution (blue rectangle shapes). Blue rectangle shapes indicate solutions for the procedural steps that the blue line with the dot grasps, the blue-outlined rectangle shapes indicate examples of the solutions. Note that the preoperative procedure (indicated in yellow) and the intraoperative procedure (indicated in green) partially overlap as the approaches differ between institutions. V = prostate volume, Δs = orthogonal distance from the inner surface of the pubic arch to the ventral border of the prostate in mm, a = obstructed area by the pubic arch compared to total prostate cross-section in %, ∠ = angle between the pubic symphysis and ventral border of the prostate. The gray block overlaid on the limits for prostate volume indicates that the guideline for prostate volume is superfluous according to new brachytherapy guidelines.
Figure 4. Measuring methods of pubic arch interference (PAI). (a) Angle (α) between pubic symphysis and ventral border of prostate, (b) Orthogonal distance (Δs) from inner surface of pubic arch to ventral border of the prostate and (c) Prostate diameter blockage (d1) by the pubic arch compared to total prostate diameter (D).
Figure 5. Overview of solution strategies. (a) To improve total needle geometry in prostate with pubic arch interference (PAI), the positioning strategy can be altered by needle manipulation, a free-hand positioning technique, transrectal ultrasound (TRUS) probe manipulation, additional needles, template manipulation, or positioning the patient in the extended lithotomy position. The needle design can be changed by developing a passive steerable needle (e.g. with a pre-bent or a bevel-shaped tip) or an active steerable needle. The needle guidance can be adapted by using a patient-specific template, a template sutured to the patient’s perineum instead of attached to the TRUS probe, or robotic implantation of the needle. (b) To improve transperineal needle positioning into the prostate, needle positioning accuracy can be improved by altering the positioning strategy or changing the needle design. The positioning strategy can be altered by tissue manipulation, needle manipulation, needle repositioning, template manipulation, or robotic implantation. The needle design can be changed by developing an anchoring needle, a passive steerable needle (e.g. with a bevel-shaped tip), or an active steerable needle.
