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Twenty-three Gauge Cannula System with Microvitreoretinal Blade Trocar
  1. Makoto Inoue1,*,
  2. Kei Shinoda2,
  3. Akito Hirakata1
  1. 1 Kyorin Eye Center, Kyorin University School of Medicine, Japan;
  2. 2 Department of Ophthalmology, Teikyo University School of Medicine, Japan
  1. Correspondence to: Makoto Inoue, Ophthalmology, Kyorin Eye Center, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan; inoue{at}


Aims: To report on a 23-gauge cannula with a microvitreoretinal (MVR) blade trocar which improved wound closure after vitrectomy and reduced the incidence of postoperative hypotony.

Methods: The resistance of inserting a 23-gauge MVR trocar-cannula through the porcine sclera was compared to that with the conventional 23-gauge trocar-cannula. The incidence of postoperative hypotony (intraocular pressure < 6 mmHg) was determined for 48 eyes that underwent vitrectomy with the 23-gauge MVR trocar-cannula and 30 eyes with the conventional 23-gauge trocar-cannula. The eyes were examined on postoperative days 1, 2, and 7. The closure of the sclerotomies were examined by optical coherence tomography in 9 eyes in each group on postoperative days 1, 3, and 7, and at one month.

Results: The resistance of inserting the MVR trocar-cannula was lower than that with the conventional trocar-cannula. In patients, a transient hypotony was found at postoperative day 1 after the vitrectomy in 2 eyes (4%) with the MVR trocar-cannula, and in 7 eyes (23%) with the conventional trocar-cannula (P= 0.023). An unclosed incision was detected in 9 sclerotomies (50%) with the MVR trocar-cannula and 16 sclerotomies (89%) with the conventional trocar-cannula (P= 0.028) at postoperative day 1, and the incidence of an opened incision was also significantly higher with the conventional trocar-cannula on days 3 and 7 but not after 1 month (P= 0.003, P= 0.008, P= 0.486, respectively).

Conclusion: The MVR trocar-cannula leads to better postoperative wound closure and reduces the incidence of postoperative hypotony.

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