Oblique parallel insertion may be safer for performing 25-gauge vitrectomy

Using oblique parallel incisions to perform 25-gauge pars plana vitrectomy may allow for faster, more complete postoperative wound sealing compared with standard straight incisions, according to a study by researchers in Italy. Better wound closure could in turn improve the safety of surgery involving extensive manipulation, the study authors noted.

"The standard straight incision for 25-gauge vitrectomy may not close well at the end of surgery with postoperative hypotony. To overcome incompetent wound closure, oblique insertion of the trocars has been suggested," the authors noted.

"We have developed an oblique incision, which is parallel to the scleral fibers instead of perpendicular and therefore avoids cutting," they said.

Stanislao Rizzo, MD, and colleagues compared the effectiveness of oblique-parallel insertions, oblique-perpendicular insertions and straight incisions for performing 25-gauge vitrectomy in three groups of 15 patients with macular holes.

Oblique-parallel insertion allowed for immediate wound self-sealing after removing the 25-gauge cannula. At 1 day postop, all sclerotomies were well healed, with the internal wound lips showing "perfect" apposition. Additionally, 39 sclerotomies were undetectable on ultrasound biomicroscopy (UBM) and six were only slightly evident, according to the study.

For the oblique-perpendicular insertion group, the incisions also appeared airtight immediately postop. Also, all sclerotomies were well-healed at 1 day postop, although all had a minimal gape visible on UBM. At 1 month, these gapes were no longer detectable in 20 sites, but remained evident in 25 sites, the authors reported.

Three eyes also showed peripheral cilio-choroidal detachment at 1 day postop, which had resolved by 7 days follow-up, according to the study.

Among eyes in the standard straight incision group, 10 cases developed conjunctival blebs. Of these, seven cases required air-gas refilling and three required suturing of the sclerotomies.

Additionally, at 1 day postop, five patients had developed hypotony and UBM showed significant gapes in all sites, weak vitreous entrapment in 36 sites, subconjunctival fluid in four sites and cilio-choroidal detachment in seven sites, according to the study.

At 7 days postop, the hypotony had recovered in all five patients, and cilio-choroidal detachment had disappeared in four sites and had reduced in three sites.

The sclerotomy defect remained detectable at 1 month, but other complications were no longer evident, the authors noted.

The study is published in the September issue of Graefe's Archive for Clinical and Experimental Ophthalmology.