ELIMINATION OF INFUSION BUBBLES AND UNCONTROLLED REFLUX IN THE ALCON CONSTELLATION VITRECTOMY VISION SYSTEM STEPHEN R. RUSSELL, MD,*† ELLIOTT H. SOHN, MD,*† H. CULVER BOLDT, MD,*† JAMES C. FOLK, MD,*† RYAN M. TARANTOLA, MD,‡ CHRISTINE N. KAY, MD,*§ VINIT B. MAHAJAN, MD, PHD*†¶ Purpose: To identify the sources and management of 2 problems associated with the Alcon Constellation Vitrectomy (Alcon Laboratories, Inc) System: 1) infusion bubbles and 2) uncontrolled reflux. Methods: Surgical and analytical videos were evaluated to identify the source of intraoperative bubbles, which localized to the duckbill valve (DV). Intraoperatively, the authors modified the infusion tubing and its control by removing the DV. The DV was repurposed as a one-way valve to block reflux originating from the vitrectomy console. Results: Twenty consecutive 23-gauge vitrectomies in 20 eyes of 20 subjects from 2 surgeons (S.R.R. and E.H.S.) were reviewed. Infusion bubbles at the DV developed with each transitory tubing pressure drop upon opening of the infusion clamp. Removal of the DV from the infusion line eliminated infusion bubbles in 20 consecutive 23-gauge cases. Adding a one-way valve, which was fashioned from the DV, to the aspiration tubing, resulted in elimination of infusion bubbles and console-originated reflux in 20 eyes. Placement of the DV to block reflux eliminated both uncontrolled and purposeful console-originated reflux. Conclusion: Intraoperative modification of Constellation tubing may eliminate two potentially harmful problems until manufacturer correction is instituted. Because the authors’ modified connections represent off-label connectivity, the manufacturer cannot contact potentially affected surgeons or suggest temporary alternative connectivity improvements. RETINA 33:803–806, 2013 W hen using the Constellation Vitrectomy Sys- tem (Alcon Laboratories, Inc, Fort Worth, TX), we and others have observed 2 problems: 1) frequent excessive formation of intraocular air bub- bles within the infusion line and 2) sudden reflux of fluid with cessation of aspiration (for examples of each, see Videos, Supplemental Digital Con- tents 1 and 2, http://links.lww.com/IAE/A119 and http://links.lww.com/IAE/120). Particularly in phakic cases, infusion bubbles that have migrated into the anterior chamber or become trapped in the vitreous adjacent to the crystalline lens hinder the view or require compromise of the anterior chamber integrity to remove them. One of the novel changes of the Constellation infusion system was the addition of a special mixing valve, known as the duckbill valve (DV), which allows either fluid or air to be infused without requiring a user-activated hydraulic switch at the confluence. We hypothesized that the source of most infusion bubbles originated from the DV. Second, we have experienced uncommon, unex- pected, and unintentional forceful reflux through extrusion cannulas and vitrectomy cutters, occurring immediately after releasing the aspiration foot pedal. In two of our recent cases, the hydraulic force from reflux was sufficient to create holes in attached retina. These instances have been reported to the Federal Drug Administration via MedWatch surveillance, and these and other complications from the Constellation can be searched for at: http://www.accessdata.fda.gov/ scripts/cdrh/cfdocs/Medsun/SearchReportText.cfm. We hypothesized that the origin of the inadvertent forceful reflux resulted from a hydraulic surge within the Constellation console or cassette. As a corollary, we suggest that adding a one-way hydraulic valve fashioned from the DV could block reflux originating downstream. 803