Novel syringe handle for one-handed anterior chamber paracentesis

Abstract

Background: Anterior chamber (AC) paracentesis is a valuable diagnostic and therapeutic ophthalmic procedure, but the conventional technique poses ergonomic and safety challenges.

Methods: We developed a custom, low-cost, 3D-printed syringe handle that enables one-handed AC paracentesis using standard 1-mL syringes by allowing single-finger plunger retraction. In a randomized controlled wet-lab study, ten ophthalmology residents each performed four AC paracentesis procedures (two with the novel device, two with the conventional technique) on porcine eyes. The primary outcome was successful aspiration of ≥ 100 µL of aqueous humor. Secondary outcomes included intraocular injury, aspirated volume, procedure time, and responses to an anonymous post-procedure survey.

Results: All AC paracentesis procedures achieved ≥ 100 µL of fluid. No intraocular injuries occurred with the novel device, compared to 2 intraocular tissue contacts with the conventional method. The median aspirated volume was 120 µL (interquartile range [IQR]: 110-150 µL) with the novel device, close to the 100 µL threshold, with no extractions exceeding 200 µL. In contrast, the conventional method yielded a significantly higher median volume of 200 µL (IQR 140-270 µL; P < 0.001), with 25% of procedures exceeding 250 µL. The median procedure time was 26.9 s with the novel device versus 35.7 s with the conventional method, a 8.8 s (25%) reduction (P = 0.13). Participants generally preferred the novel device for ease of use, control, and perceived safety. Nine of 10 participants reported feeling more or much more confident about performing AC paracentesis safely with the novel syringe handle than with the conventional technique.

Conclusions: We developed a novel syringe handle for one-handed AC paracentesis, which improved the safety and precision of the procedure while reducing procedural time. Its low-cost, reusable design and compatibility with standard syringes make it a practical tool for the procedure. Further clinical studies are warranted to explore broader applications.

Keywords: Anterior chamber paracentesis; New instrument; Syringe.

Fig. 1

Demonstration of the novel syringe handle for anterior chamber paracentesis. (A) The 3D-printed syringe handle comprises a slider and a housing. (B) The assembled syringe handle features a hard stop at the 0.2 mL syringe mark (red arrow), preventing the extraction of more than 0.2 mL of aqueous fluid. (C) A photograph illustrating the syringe handle in use during anterior chamber paracentesis, where the user performs one-handed paracentesis with the right hand while stabilizing the eye using a cotton-tip applicator in the left hand. (D) The two-handed anterior chamber paracentesis technique used in the wet lab study, where one hand holds the syringe barrel while the other pulls the plunger

Fig. 2

Wet lab study results comparing the novel syringe handle to the conventional two-handed anterior chamber paracentesis technique (40 procedures, 10 participants). A, Boxplot of extracted aqueous volume. All participants successfully extracted at least 100 µL using both methods. The novel handle had a median [interquartile range (IQR)] of 120 [110–150] µL, close to the 100 µL target, with no extractions exceeding 200 µL. In contrast, the conventional method yielded significantly higher volumes (200 [140–270] µL, P < 0.001), with 25% of procedures exceeding 250 µL. B, Boxplot comparing procedure time between the two methods. The median and IQR for the novel method was 26.9 [22.5–33.1] seconds, while the conventional method took 35.7 [22.3–41.6] seconds (P = 0.13)

Fig. 3

Results of the anonymous survey from 10 participants after the wet lab study. Participants rated each question on a scale from 1 to 5, with 5 indicating the most favorable response toward the novel syringe handle. All responses ranged from 3 to 5. Each bar represents aggregated responses to post-procedure usability and preference questions