Novel method to quantify traction in a vitrectomy procedure

Teixeira, Anderson; Chong, Lawrence P.; Matsuoka, Naoki; Rowley, Adrian P.; Lue, Jaw-Chyng; McCormick, M.; Kerns, Ralph; Humayun, Mark S.

doi:10.1136/bjo.2009.166637

Cited by 20 publications

(14 citation statements)

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“…The traction forces decreased by 2.51 dynes for each 500 cuts per minute increase (P , 0.05), so they showed that the traction was directly proportional to the aspiration vacuum and inversely proportional to the cut rate. 31,32 So, in conclusion, the new-generation UHS 25-gauge Constellation vitreous cutter may provide a new paradigm for high-flow, smaller-diameter instrumentation, thus increasing the efficiency of the small-gauge technique and the safety of the surgery.…”

Section: Discussionmentioning

confidence: 99%

Comparative Study Between a Standard 25-Gauge Vitrectomy System and a New Ultrahigh-Speed 25-Gauge System With Duty Cycle Control in the Treatment of Various Vitreoretinal Diseases

Rizzo

Genovesi-Ebert

Belting

2011

Retina

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Section: Discussionmentioning

confidence: 99%

Comparative Study Between a Standard 25-Gauge Vitrectomy System and a New Ultrahigh-Speed 25-Gauge System With Duty Cycle Control in the Treatment of Various Vitreoretinal Diseases

Rizzo

Genovesi-Ebert

Belting

2011

Retina

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“…created by vitreous cutters during vitrectomy has been a challenge and the only reproducible data were reported by Teixeira et al 13,23 In their study, an ocular model allowed measurement of vitreoretinal traction during vitreous removal with a vitrectomy probe (measured in dynes). They determined that vitreoretinal forces decrease by 2.5 dynes for every cutting speed increase of 500 cpm (P , 0.05).…”

Section: Discussionmentioning

confidence: 99%

“…An evolved version of a previously described experimental eye set-up was used for tractional force testing and is briefly described below. 13 The fluidics performance of the 23-gauge cutters was tested with a Spring Return vitrectomy system (Stellaris PC system; Bausch & Lomb) and a Dual Pneumatics system (Constellation Vision System; Alcon Labs Inc) using the standard DC setting (CORE-biased open), according to methodology previously developed by Diniz et al 14,15 Briefly, for the flow tests, each cutter was suspended in a vial of either water or porcine vitreous. The vials were placed on a high-sampling (2 samples/second), precision (0.01 g) balance (Ohaus Corp, Parsippany, NJ) that measured the weight of the remaining water or vitreous throughout each experiment.…”

Section: Methodsmentioning

confidence: 99%

Effects of a Modified Vitrectomy Probe in Small-Gauge Vitrectomy

Rizzo

Fantoni

Santis

et al. 2017

Retina

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Purpose: Thorough this experimental study, the physic features of a modified 23-gauge vitrectomy probe were evaluated in vitro.Methods: A modified vitrectomy probe to increase vitreous outflow rate with a smalldiameter probe, that also minimized tractional forces on the retina, was created and tested. The "new" probe was created by drilling an opening into the inner duct of a traditional 23-gauge probe with electrochemical or electrodischarge micromachining. Both vitreous outflow and tractional forces on the retina were examined using experimental models of vitreous surgery.Results: The additional opening allowed the modified probe to have a cutting rate of 5,000 cuts per minute, while sustaining an outflow approximately 45% higher than in conventional 23-gauge probes. The modified probe performed two cutting actions per cycle, not one, as in standard probes. Because tractional force is influenced by cutting rate, retinal forces were 2.2 times lower than those observed with traditional cutters.Conclusion: The modified probe could be useful in vitreoretinal surgery. It allows for faster vitreous removal while minimizing tractional forces on the retina. Moreover, any available probe can be modified by creating a hole in the inner duct.RETINA 0:1-10, 2016 S utureless pars plana vitrectomy (PPV) reduces postoperative inflammation at sclerotomy sites, decreasing patient postoperative discomfort and recovery time. 1-6 Unfortunately, these advantages are often mitigated by longer operation times, which are mainly caused by reduced vitreous outflow rates. The smaller diameter of the probe leads to a decreased vitreous outflow and possibly exposes the surrounding retinal tissue to higher tractional forces because of the resulting higher aspiration pressures. 7,8 Poiseuille law, which governs flow inside of a pipe, is applicable to a vitrectomy probe and states that volumetric flow is proportional to tube radius to the fourth power (r 4 ). Therefore, the vitreous aspiration rate is decreased by a factor of 6.6 with a 25-gauge vitreous cutter, compared with the aspiration rate obtained with a 23-gauge vitreous cutter, because of its smaller port and tube radius. To achieve acceptable values of the vitreous outflow, higher aspiration values (at least 600 mmHg) can be used and, because flow is also inversely proportional to tube length, the length of both the probe tube and the aspiration ducts can be reduced. Vitrectomy probes are pipes that are not always open. The end of the probe is equipped with a guillotine that continuously opens and closes, and the percentage of

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“…Complications include endophthalmitis, enlargement and reopening of macular hole, increase in lens opacity, iris new-vessels, neovascular glaucoma, pigment epithelium loss, photic toxicity, retinal breaks and detachment, and vitreous hemorrhage (Benson et al, 1988;LopezLopez et al, 2009;Park et al, 1995) .Some of these complications can be explained by the fact that aspirating and shearing the vitreous generate considerable amount of traction force on the retina (Teixeira et al, 2010). Pharmacologic vitreolysis can be an alternative option in the future, but its current development still remains challenging (Lopez-Lopez et al, 2009).…”

Section: Discussionmentioning

confidence: 99%