Core Vitrectomy Procedure
Core vitrectomy is performed by removing the central vitreous gel using a 23-, 25-, or 27-gauge vitrectomy system, followed by inducing posterior vitreous detachment and extending vitreous removal anteriorly to at least the equator. 1, 2
Surgical Setup and Access
Create standard 3-port pars plana access using small-gauge (23-, 25-, or 27-gauge) instrumentation under local monitored anesthesia care or general anesthesia for anxious patients. 1, 2
Position the infusion cannula temporally, though be aware this placement historically contributed to temporal visual field defects from air streaming during fluid-air exchange. 1
Core Vitrectomy Steps
Initial Vitreous Removal
Remove the central vitreous gel using the vitrectomy cutter with aspiration to clear the core vitreous cavity. 1, 2
Inject triamcinolone acetonide after core vitrectomy to highlight the posterior vitreous cortex and any remaining vitreous, facilitating complete visualization. 1, 2
Posterior Vitreous Detachment Induction
Induce complete posterior vitreous detachment by separating the posterior cortical hyaloid from the optic nerve and macula using aspiration, an illuminated pick, or forceps. 1
The posterior hyaloid must be completely detached from the retinal surface, particularly over the macula, to release all tractional forces. 1, 2
Peripheral Vitreous Removal
Extend vitreous separation anteriorly to at least the equator and perform thorough peripheral vitreous shaving, particularly near the cannulas, to minimize iatrogenic retinal break risk during instrument exchanges. 1, 2
Complete peripheral vitreous removal is critical, as inadequate anterior extension is a significant risk factor for surgical failure. 2
Visualization Enhancement
Use vital dyes selectively - indocyanine green, trypan blue, or triamcinolone can be used off-label to highlight the internal limiting membrane and remaining vitreous, though their safety remains somewhat controversial. 1
Very low concentrations of dyes appear safe and minimize retinal trauma by improving visualization. 1
Minimize excessive intraoperative light exposure to the macula to prevent phototoxicity. 1
Technical Considerations
Modern high-speed cutters (up to 16,000 cuts per minute) with near 100% duty cycle performance improve flow control and surgical efficiency. 3
The smaller diameter of modern vitrectomy probes allows positioning between narrow spaces and can serve as a multifunctional instrument. 3
Mean core vitrectomy time is approximately 204 seconds, with total vitrectomy (including shaving) averaging 534 seconds. 4
Critical Pitfalls to Avoid
Incomplete posterior vitreous detachment - failure to completely separate the posterior hyaloid leads to persistent traction and surgical failure. 1
Inadequate peripheral vitreous removal - insufficient anterior extension of vitreous removal increases risk of postoperative retinal tears (3-17% incidence) and detachment (1-5% incidence). 1, 2, 5
Excessive instrument contact with the optic disc during manipulation can cause mechanical injury to peripapillary vasculature or nerve fiber layer. 1
High-pressure air flow during subsequent fluid-air exchange can cause retinal dehydration damage; minimize prolonged air flow at high pressure and consider humidifying the air. 1