Vitreoretinal Traction Created by Conventional Cutters during Vitrectomy

Teixeira, Anderson; Chong, Lawrence P.; Matsuoka, Naoki; Arana, Luis Alejandro Vinatea; Kerns, Ralph; Bhadri, P.; Humayun, Mark S.

doi:10.1016/j.ophtha.2009.11.004

Cited by 65 publications

(51 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…To add to the complexity, vitreous itself is a heterogeneous substance which exhibits viscoelastic properties: it is elastic and deformable and this affects the resultant tractional forces applied to the retina during vitrectomy. As such it is also hard to model, but clinical experience confirmed by careful experimental studies shows that retinal traction increases with proximity of the cutter to the retina during vitrectomy as well as with aspiration flow rate and reduces with increasing cut rate [3]. During core vitrectomy, in the centre of the vitreous cavity with an attached retina, higher aspiration flows are useful, but during vitreous shaving with a mobile detached retina, lower flows are needed.…”

Section: Outflowmentioning

confidence: 99%

Vitrectomy Fluidics

Steel

Charles

2011

Ophthalmologica

View full text Add to dashboard Cite

The goal of all vitreous surgery is to perform the desired intraoperative intervention with minimum collateral damage in the most efficient way possible. An understanding of the principles of fluidics is of importance to all vitreoretinal surgeons to achieve these aims. Advances in technology mean that surgeons are being given increasing choice in the settings they are able to select for surgery. Manufacturers are marketing systems with aspiration driven by peristaltic, Venturi and hybrid pumps. Increasingly fast cut rates are offered with optimised, and in some cases surgeon-controlled, duty cycles. Function-specific cutters are becoming available and narrow-gauge instrumentation is evolving to meet surgeon demands with higher achievable flow rates. In parallel with the developments in outflow technology, infusion systems are advancing with lowering flow resistance and intraocular pressure control to improve fluidic stability during surgery. This review discusses the important aspects of fluidic technology so that surgeons can select the optimum machine parameters to carry out safe and effective surgery.

show abstract

Section: Outflowmentioning

confidence: 99%

Vitrectomy Fluidics

Steel

Charles

2011

Ophthalmologica

View full text Add to dashboard Cite

show abstract

“…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%

“…Therefore, as the cutting rate increased, traction decreased by an average factor of 2.2 for the cutter tested. 23 Thus, tractional forces on the retina can be minimized by increasing the cutting speed. In addition, traditional vitrectomy probes produce minimum traction when the mouth of the cutter is fully closed and maximum traction when the mouth of the cutter is fully open.…”

Section: Discussionmentioning

confidence: 99%

“…Analogously, during one cutting cycle, a standard vitrectomy probe cuts only one time per cycle (distal cutting edge of inner needle), whereas the modified vitrectomy probe cuts two times per cycle (distal cutting edge of inner needle, drilled hole). [21][22][23] Actually the presence of an additional hole could correspond to a theoretical double number of cuts per time unit because the vitreous is cut twice in a cycle the first time thanks to the guillotine and the second thanks to the hole. The increased number of cuts should be the reason why we measured such a reduction of the force on the retina (lower values of the traction force peaks).…”

Section: Tractional Forces On the Retinamentioning

confidence: 99%

See 1 more Smart Citation

Effects of a Modified Vitrectomy Probe in Small-Gauge Vitrectomy

Rizzo

Fantoni

Santis

et al. 2017

Retina

View full text Add to dashboard Cite

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

show abstract

“…Therefore, high cut rates may allow increased flow in viscous fluid 10 and porcine vitreous 15 to a certain point and may reduce the problematic risk factor of retinal breaks caused by removal of vitreous that is adherent to retinal tissue. 16 Given the importance of the balance between flow rate and IOP during vitrectomy, the current study evaluated the effect of cut rate, duty cycle, and aspiration vacuum on fluid flow rate and IOP using high-speed dual-pneumatic 7500-cpm probes and compared their performance with 5000-cpm probes.…”

Section: As Shown In Equationmentioning

confidence: 99%

Performance Comparison of High-Speed Dual-Pneumatic Vitrectomy Cutters during Simulated Vitrectomy with Balanced Salt Solution

Abulon

Buboltz

2015

Trans. Vis. Sci. Tech.

View full text Add to dashboard Cite

Purpose: To measure flow rate of balanced salt solution and IOP during simulated vitrectomy using two sets of high-speed dual-pneumatic probes.Methods: A closed-model eye system measured IOP and flow rate of a balanced salt solution through infusion cannula. The Constellation Vision System was tested with two sets of high-speed dual-pneumatic probes (UltraVit 23-gauge and enhanced 25þ-gauge 5000-cpm probes; UltraVit 23-gauge and enhanced 25þ-gauge 7500-cpm probes; n ¼ 6 each) under different vacuum levels and cut rates in three duty cycle modes.Results: In both probe sets, flow rates were dependent on cut rate with the biased open and biased closed duty cycles. Flow rates were highest with the biased open duty cycle, lower with the 50/50 duty cycle, and lowest with the biased closed duty cycle. IOP, as expected, was inversely associated with flow rate using both probe sets.

show abstract

Vitreoretinal Traction Created by Conventional Cutters during Vitrectomy

Cited by 65 publications

References 15 publications

Vitrectomy Fluidics

Vitrectomy Fluidics

Effects of a Modified Vitrectomy Probe in Small-Gauge Vitrectomy

Performance Comparison of High-Speed Dual-Pneumatic Vitrectomy Cutters during Simulated Vitrectomy with Balanced Salt Solution

Contact Info

Product

Resources

About