Reply




We thank Drs Masri and Steel for their interest in our recent publication regarding outcomes of 27 gauge pars plana vitrectomy (PPV) for posterior segment disease.


The authors provided operative time data (both overall time and the time in which the cutter was activated, or “cutting” time) for their own series comparing eyes undergoing 25 gauge PPV (30 eyes) and 27 gauge PPV (30 eyes) with membrane peeling for macular pucker or hole indications. Similar to our publication, the authors did not find a significant difference in total operative time between larger-gauge and 27 gauge instruments, and they offer new information that no difference existed in regard to “cutting” time as well. The authors note that “cutting” time comprised ∼20% of total operative time, and they offer this as an explanation as to why use of smaller-gauge instrumentation did not significantly affect total operative time despite reduced flow rate. In addition, the authors offered that increased pivoting of smaller, 27 gauge instruments allows for improved maintenance of vitreous contact and thus could explain why “cutting” time was also similar to larger, 25 gauge instrumentation.


As noted in our publication, prior studies have demonstrated that dual-pneumatic probes, despite using smaller-diameter instruments, are able to preserve flow rate by maintaining duty cycles at high cut rates. We offered this as a possible explanation as to why total operative time was not significantly increased with 27 gauge instruments. While the hypothesis of Drs Masri and Steel that altered surgical technique, with increased pivoting within sclerostomy sites to maintain vitreous contact, might also help compensate for reduced flow rate is certainly plausible, such hypotheses must be tested in a prospective, randomized, comparative trial including varied surgical indications beyond macular cases, in which removal of the peripheral cortical vitreous gel may not be as critical. Such a study, with inclusion of patient satisfaction and/or objective grading of postoperative pain or inflammation, would be helpful to further identify the benefits of 27 gauge vitrectomy compared to larger-gauge equivalents.


The additional data from Drs Masri and Steel help to support the finding of our study that use of 27 gauge instrumentation does not seem to significantly increase total surgical time. Further study will be helpful to determine the precise mechanisms as to how, despite reduced flow rate, both “cutting” time and operative time are maintained.

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Jan 6, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Reply

Full access? Get Clinical Tree

Get Clinical Tree app for offline access