الفهرس 
Indications of Pars Plana VitrectomyOnly 14 pages are availabe for public view
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Abstract
Pars plana vitrectomy as a technique has revolutionized retinal surgery since its advent. It allowed the removal of traction by an internal method, essential in retinal detachment procedures, as well as provided an active modality for vitreous hemorrhage and opened the door for surgical intervention in a variety of retinal pathologies.
The evolution of vitrectomy surgery has seen experimentation and implementation of smaller surgical instruments aimed at greater functionality and minimalization of ocular trauma. The basis of sutureless pars plana vitrectomy was to stabilize intraocular pressure during surgery, with a truly closed system, as well as reduce surgical time by removing the need for sutured wound closure.
Sutureless vitrectomy has rapidly been accepted as an essential part of vitreoretinal surgical setup. The size and structure of the wound along with near intact conjunctival covering makes the incision self-sealing and safe. This allows the vitrectomy instruments to be used without creating an initial limited peritomy to expose sclera, and obviates the need for sutures at the end of the procedure. Wound construction is the essential step in ensuring post operative stability. Both one-step and two-step wound constructions have been described. Key points include an oblique, tunneled approach to ensure a valve-like effect as well as misalignment of conjunctival and sclera wounds by displacing conjunctiva during construction.
After the 25-gauge vitrectomy was introduced in 2002, transconjunctival sutureless vitrectomy became the standard procedure used in many vitreoretinal surgeries. In transconjunctival sutureless vitrectomy, three cannulas are inserted in the pars plana through the conjunctiva and sclera. The infusion line and vitreoretinal instruments are then introduced into the vitreous cavity through these cannulas. At the end of the procedure, the cannulas are removed without suturing either the sclera or the conjunctiva.
Sutureless vitrectomy has a number of advantages, including improved patient comfort, more rapid postoperative recovery, and in many cases shortened surgical opening and closing times.
A major limitation of the 25-gauge system is that the instruments are too flexible for many of the complicated maneuvers performed on the retina and vitreous body. To contend with this difficulty, the 23-gauge TSV system was initiated. The 23-gauge instruments are wider and more rigid than those of the 25-gauge system, allowing surgeons to perform more complex maneuvers.
While use of the 23-gauge openings confers the advantages of sutureless surgery, it has the disadvantage of requiring a completely different set of flexible instruments, keeping surgery costly. To overcome this drawback, the 20-gauge system was invented in 2007, which allows the use of the readily available 20-gauge vitrectomy instruments for transconjunctival sutureless surgery.
The 20-gauge system presents advantages over the 25/23 gauges, without their inconveniences. It shortens the procedure for being transconjunctival and sutureless. It also provides faster healing and less post-operative inflammation compared to other existing trocar systems.
Although the development of 27-gauge vitrectomy is an ongoing project and has not yet been established as a widely accepted system, the feasibility and safety of 27-gauge vitrectomy in selected cases have been demonstrated and confirmed. Further development and refinement of the 27-gauge instruments’ stiffenss and functionality will continue over the coming years and allow surgeons to establish an ultra-minimally invasive surgery system for vitreoretinal diseases in the near future.