Since the introduction of systems for sutureless vitrectomy surgery, there has been debate about which approach is best. We now have options for 20-, 23-, 25-, and 27-gauge instrumentation. Which can provide the best results: the most efficient surgery with the fastest healing, the least inflammation, and the fewest postoperative complications? Which is the most cost-effective? It will take time to answer all these questions.
Of the available options, 20-gauge non-trocar or trocar systems hold the possibility of providing some of the advantages of smaller-gauge systems without the need to adopt a lot of newer instrumentation in switching to transconjunctival sutureless surgery.
We retrospectively reviewed our early results with two relatively recently introduced 20-gauge trocar systems: the Claes 20 Gauge Vitrectomy System (DORC International, Zuidland, Netherlands), and the One-Step Surgical System (Synergetics, O'Fallon, MO).1
FIRST 40 CASES
We performed a retrospective, comparative case
series review of the first 40 surgeries performed by a single
surgeon with the two above-named 20-gauge trocar
systems for transconjunctival sutureless vitrectomy surgery.
The 40 cases with the DORC system (Figure 1)
were performed from May to July 2008, and the 40
cases with the Synergetics system (Figure 2) from
January to April 2009. Charts and videos for these 80 cases were reviewed.
Sclerotomies with the DORC system were created using a two-step procedure; a regular 20-gauge microvitreoretinal knife is inserted at an estimated angle of 10° to 20° using the DORC fixed footplate; then the trocar is inserted (Figures 3-5). For insertion of the Synergetics trocars, the bladed trocar inserter is used. I use the same DORC footplate with the Synergetics trocars, as it provides good stabilization of the globe (Figures 6-8). I always make sure that I see the tip of the trocar after inserting, to ensure that it does not end up in the subretinal space. Standard wide-angle vitrectomy is then performed.
The trocars are removed either by reinserting the guide inserter on the trocar before pulling it out of the sclerotomy, or by pulling out the trocar directly without the guide. The sclerotomy sites are checked for leakage before the conclusion of the case. Standard postoperative care instructions are given.
Vitreous substitutes used in these cases included SF6 or C3F8 gases, silicone oil, balanced saline solution, and air. I used more air/fluid exchanges in the second series, as I have found that air has a greater surface tension and it seals the sclerotomies better.
RESULTS
Baseline visual acuities and intraocular pressures were
similar in the two groups. The demographics and the
mix of indications for surgery was also similar between
the groups (Table 1).
Intraoperative hypotony was noted more frequently in the cases performed with the DORC system (n=3) compared with the Synergetics system (n=1). Hypotony usually occurred during instrument exchange.
Suturing of sclerotomies was performed in an equal number of cases in the two groups (n=3 in each group). All additional suturing required only one suture on only one sclerotomy. All three of the cases requiring sutures with the DORC system were performed with silicone oil. Of the cases requiring sutures with the Synergetics system, two had silicone oil and one had balanced saline solution. No additional suturing was done postoperatively in either group.
No postoperative complications were noted at up to 3 months follow-up after the procedure, including no occurrences of endophthalmitis and no retinal detachments.
Surgical time was similar with both systems. Intraocular pressures at 1 day, 1 week, and 1 month were also similar (Table 2).
COMPARISONS AND CONCLUSIONS
These two 20-gauge trocar systems are comparable
for use during transconjunctival sutureless surgery.
However, we observed some differences in the course of
this retrospective review of cases.
The DORC instruments tend to glide easily during instrument exchange, while the Synergetics instruments tend to experience more friction. Because of this difference in friction, the trocars of the DORC system are not easily removed during instrument exchange, while the Synergetics instruments may tend to pull the trocars along when an instrument is withdrawn.
The DORC system is reusable, while the Synergetics instrumentation is single-use. The silicone stopper of the DORC system is only partially effective, while the flexible cannula of the Synergetics system tends to selfseal during surgery.
Trocar insertion was easy with both systems. Closure rate and need for suturing were similar. The incisions tended to close faster with the Synergetics system because the trocar conforms better to the slit-like sclerotomies, unlike with the DORC system, which uses a rigid, round design.
Use of angled instruments is limited because of the systems' designs. The availability of better instrumentation in the future will be of benefit, including scissors and picks designed to pass through a 20-gauge system, and embedded self-sealing valves.
Sutureless 20-gauge vitrectomy shows promise to become a useful tool in our arsenal for less-invasive posterior segment surgery.
Narciso F. Atienza Jr., MD, DPBO, is in practice at the Cardinal Santos Medical Center; St. Luke's Medical Center, Quezon City; and the Legaspi Eye Center in the Philippines. Dr. Atienza states that he has no financial interests relevant to the products or companies discussed in this article. He may be reached via e-mail at retinasurgeon@gmail.com.
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