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Synechiolysis, capsulotomy. (A) Patient 9 with chronic uveitis for many years. He presented with mature cataract and posterior iris synechiae. Dissection of the synechiae with conventional instruments was not successful. (B) Pulsed electron avalanche knife (PEAK-fc) allowed for selective tissue dissection without affecting adjacent tissues such as lens capsules or iris vessels. (C) After separation of the iris with PEAK-fc, the anterior chamber was again padded with viscoelastic material. Massive iris pigment deposition made a conventional continuous curvilinear capsulorhexis impossible. (D) Capsulotomy performed with PEAK-fc using a voltage level of 500 V and a repetition rate of 100 Hz. (E) Note the sharp edges of the lens capsulotomy. Because of potential inflammatory response, primary implantation of an intraocular lens was resigned.
Source publication
The pulsed electron avalanche knife (PEAK-fc) is a new pulsed electrosurgical device that allows for precise, "cold" and traction-free tissue dissection.
To evaluate the surgical applicability, safety and potential complications of PEAK-fc in complicated cataract surgery.
The study included five children with congenital cataracts, two patients with...
Contexts in source publication
Context 1
... comparison to dissection of retinal tissue, 5 a higher voltage level and increased repetition rate (600 V, repetition rate 60-100 Hz) were used, resulting in most effective cutting. Successful performance of capsulotomy required a slow movement of the probe along the capsule in a circular manner with a velocity of approximately 1 mm/s. The lens capsule was just gently touched, thereby avoiding tractional forces and pressure on the capsule. PEAK-fc cuts showed sharp edges with hardly visible whitening, indicating very little collateral damage ( fig 2B). Even in cases of massive pigment deposition after removal of iris synechiae, continuous circular capsulotomies could be performed ( fig 3C). In two cases, surgeons initially failed to successfully perform a continuous curvilinear capsulorhexis with a capsulorhexis forceps (table 2). Capsulorhexis margins showed an extensive radial rip with impending injury of the posterior capsule. Subsequently, PEAK-fc was applied and a circular anterior capsulotomy could be successfully completed, thereby avoiding a tear in the posterior capsule and allowing for an intraocular lens implantation into the capsule ...
Context 2
... was also successfully used for the separation of posterior iris synechiae (fig 3) in a patient with a history of severe post-traumatic inflammation and in two patients with chronic uveitis for many years. All of them presented with mature cataracts and an iris that was completely tightly attached to the lens capsule. Attempts to loosen these synechiae with conventional instruments were unsuccessful ( fig 3A). However, with PEAK-fc, these tight synechiae could be released without damaging the lens capsule ( fig 3B,C). Only a minimal bleeding occurred in iris vessels, which stopped spontaneously. After successful synechiolysis, surgery was continued, with capsulotomy performed using PEAK-fc in all cases. In cases of uveitis, the lens capsules were covered with different amounts of residual iris pigment, which might have made a conventional continuous curvilinear capsulorhexis very difficult or even impossible. In all these cases, PEAK-fc allowed for a round continuous capsulotomy ( fig ...
Context 3
... was also successfully used for the separation of posterior iris synechiae (fig 3) in a patient with a history of severe post-traumatic inflammation and in two patients with chronic uveitis for many years. All of them presented with mature cataracts and an iris that was completely tightly attached to the lens capsule. Attempts to loosen these synechiae with conventional instruments were unsuccessful ( fig 3A). However, with PEAK-fc, these tight synechiae could be released without damaging the lens capsule ( fig 3B,C). Only a minimal bleeding occurred in iris vessels, which stopped spontaneously. After successful synechiolysis, surgery was continued, with capsulotomy performed using PEAK-fc in all cases. In cases of uveitis, the lens capsules were covered with different amounts of residual iris pigment, which might have made a conventional continuous curvilinear capsulorhexis very difficult or even impossible. In all these cases, PEAK-fc allowed for a round continuous capsulotomy ( fig ...
Context 4
... was also successfully used for the separation of posterior iris synechiae (fig 3) in a patient with a history of severe post-traumatic inflammation and in two patients with chronic uveitis for many years. All of them presented with mature cataracts and an iris that was completely tightly attached to the lens capsule. Attempts to loosen these synechiae with conventional instruments were unsuccessful ( fig 3A). However, with PEAK-fc, these tight synechiae could be released without damaging the lens capsule ( fig 3B,C). Only a minimal bleeding occurred in iris vessels, which stopped spontaneously. After successful synechiolysis, surgery was continued, with capsulotomy performed using PEAK-fc in all cases. In cases of uveitis, the lens capsules were covered with different amounts of residual iris pigment, which might have made a conventional continuous curvilinear capsulorhexis very difficult or even impossible. In all these cases, PEAK-fc allowed for a round continuous capsulotomy ( fig ...
Context 5
... was also successfully used for the separation of posterior iris synechiae (fig 3) in a patient with a history of severe post-traumatic inflammation and in two patients with chronic uveitis for many years. All of them presented with mature cataracts and an iris that was completely tightly attached to the lens capsule. Attempts to loosen these synechiae with conventional instruments were unsuccessful ( fig 3A). However, with PEAK-fc, these tight synechiae could be released without damaging the lens capsule ( fig 3B,C). Only a minimal bleeding occurred in iris vessels, which stopped spontaneously. After successful synechiolysis, surgery was continued, with capsulotomy performed using PEAK-fc in all cases. In cases of uveitis, the lens capsules were covered with different amounts of residual iris pigment, which might have made a conventional continuous curvilinear capsulorhexis very difficult or even impossible. In all these cases, PEAK-fc allowed for a round continuous capsulotomy ( fig ...
Citations
... It applies high-frequency RF pulses to generate electrical plasma along the edge of the electrode (26). Several studies have shown that this technology allows for the precise dissection of rabbit, bovine, and human retinas and lens capsules, even when completely submerged in a liquid medium (27)(28)(29)(30). The PB system has been approved by the Food and Drug Administration (FDA) for use in the cutting and coagulation of soft tissues during otolaryngology surgical procedures. ...
Background:
Electrosurgical technology is widely used in surgical dissection and hemostasis, but the generated heat creates thermal injury to adjacent tissues and delays wound healing. The plasma blade (PB) applies pulsed radiofrequency (RF) to generate electrical plasma along the edge of a thin, flat, insulated electrode, minimizing collateral tissue damage. This study aimed to evaluate wound healing in swine skin following incision with a new surgical system that applies low-temperature plasma (NTS-100), a foreign PB, conventional electrosurgery (ES), and a scalpel blade.
Methods:
In vitro porcine skin and an in vivo porcine skin model were used in this study. Full-thickness skin incisions 3 cm in length were made on the dorsum of each animal for each of the 5 surgical procedures at 0, 21, 28, 35, and 42 days. The timing of the surgical procedures allowed for wound-healing data points at 1, 2, 3, and 6 weeks accordingly. Local operating temperature and blood loss were quantified. Wounds were harvested at designated time points, tested for wound tensile strength, and examined histologically for scar formation and tissue damage.
Results:
Local operating temperature was reduced significantly with NTS-100 (cut mode 83.12±23.55 °C; coagulation mode 90.07±10.6 °C) compared with PB (cut mode 94.46±11.48 °C; coagulation mode 100.23±6.58 °C, P<0.05) and ES (cut mode 208.99±34.33 °C, P<0.01; coagulation mode 233.37±28.69 °C, P<0.01) in vitro. Acute thermal damage from NTS-100 was significantly less than ES incisions (cut mode: 247.345±42.274 versus 495.295±103.525 µm, P<0.01; coagulation mode: 351.419±127.948 versus 584.516±31.708 µm, P<0.05). Bleeding, histological scoring of injury, and wound strength were equivalent for the NTS-100 and PB incisions.
Conclusions:
The local operating temperature of NTS-100 was lower than PB, and NTS-100 had similarly reliable safety and efficacy.
... 12,15,16 Human in vivo case series also demonstrated the safety and precise cutting in patients undergoing cataract surgery. 17 Later, the PEAK PlasmaBlade technology was applied to other tissue types. An in vivo study comparing the healing of surgical incisions made in porcine skin using a scalpel, PlasmaBlade and standard electro surgery showed that the PlasmaBlade reduced acute thermal injury depth significantly, decreased inflammation with increase in wound burst strength, and produced superior scar formation compared with conventional electrosurgery. ...
Postoperative wound‐healing problems are relatively high in post‐bariatric body‐contouring procedures, partly because of electrosurgery and the associated thermal tissue damage. This study is a retrospective randomised evaluation of the effect of a low‐thermal plasma dissection device (PEAK PlasmaBlade, Medtronic, Minneapolis, Minnesota) in comparison with conventional electrosurgery. A total of 24 patients undergoing upper arm or medial thigh lifting were randomised to PEAK PlasmaBlade on one side and to monopolar electrosurgery on the other side of the same patient. Wounds of 10 patients were examined histologically for acute thermal injury depth. Significantly lower total volume of drain output (61,1 ± 70,2 mL versus 95,1 ± 176,0 mL; P = .04) was found on the PEAK PlasmaBlade side compared with the electrosurgery side. Furthermore, the PEAK PlasmaBlade side showed fewer seromas (no case of seroma versus three seromas in the electrosurgery group) and less thermal damage (40% versus 70%; P = .26). Acute thermal injury depth from the PEAK PlasmaBlade was less than from monopolar electrosurgery (425 ± 171 μm versus 686 ± 1037 μm; P = .631). PEAK PlasmaBlade appears to be superior to traditional monopolar electrosurgery for post‐bariatric body‐contouring procedures because it demonstrated less tissue damage, lower total volume of drain output, and fewer postoperative seromas resulting in faster wound healing.
... [2,4] Other authors applied different endodiathermy devices to create a CCC in intumescent lenses. [5][6][7] Anterior capsule puncture with positive anterior chamber pressure and two-stage capsulorhexis have considerably reduced the complications of intumescent cataract surgery. [8] Other authors suggested that, instead of allowing the higher intralenticular pressure to passively equilibrate with the anterior chamber pressure, the pressure within the lens should be actively reduced by aspiration of liquefied cortical matter. ...
... OVDs [2][3][4]10] while other studies made the use of diathermy or high-frequency diathermy for the creation of an anterior capsulotomy. [5][6][7]11] Neodymium: YAG laser capsulotomy was applied to prevent extension of the capsular tear to the lens periphery in intumescent cataracts. [12,13] Gimbel [8] described a two-stage capsulorhexis technique which was initiated centrally and could be enlarged later to the intended size. ...
Purpose
To evaluate intraoperative complications during phacoemulsification of intumescent cataract using lens decompression technique.
Methods
Participants with intumescent cataract scheduled for phacoemulsification were recruited and divided into two groups. In both groups, after the anterior capsule was stained with trypan blue, the anterior chamber was filled peripherally with a dispersive ophthalmic viscosurgical device (OVD) followed centrally by a higher viscosity cohesive OVD (Healon GV). In Group 2, a 25-gauge needle was then inserted into the lens center and liquid cortex aspirated by pulling back on the syringe plunger. The outcomes measured were the incidence of capsular radial tears and the incidence of conversion to extracapsular cataract extraction (ECCE).
Results
In Group 1 (20 eyes), capsular radial tears occurred in four eyes, and in two eyes, the procedure had to be converted to ECCE. In Group 2 (20 eyes), no capsular radial tears or conversion to ECCE was reported.
Conclusion
Lens decompression technique reduced the risk of capsular radial tears and conversion to ECCE during phacoemulsification of intumescent cataract.
... 23 Compared with a manual CCC, the femtosecond laser can produce a sharp and clean-edged capsulotomy without radial nicks and tears. [24][25][26] Meanwhile, a properly sized, shaped, and centered CCC can be precisely created by a femtosecond laser for the "ideal" IOL position. [27][28][29] In the present study, a new femtosecond laser device (Catalys TM Precision Laser System) was used on all our cataract patients for the CCC incisions. ...
Purpose
To evaluate and compare the visual acuity outcomes and optical performances of eyes implanted with two diffractive multifocal intraocular lens (IOL) models with either a plate haptic design or a modified-C design.
Methods
This retrospective study comprised cataract patients who were implanted with either a plate haptic multifocal IOL model (AcrivaUD Reviol BB MFM 611 [VSY Biotechnology, Amsterdam, the Netherlands], group 1) or a modified-C haptic multifocal IOL model (AcrivaUD Reviol BB MF 613 [VSY Biotechnology, Amsterdam, the Netherlands], group 2) between June 2012 and May 2013. The 6 month postoperative visual acuity, refraction, defocus curve, contrast sensitivity, and wave-front aberration were evaluated and compared between these eyes, using different IOL models.
Results
One hundred fifty-eight eyes of 107 patients were included in this study. Significant improvement in visual acuities and refraction was found in both groups after cataract surgery (P<0.01). The visual acuity and contrast sensitivity were statistically better in group 1 than in group 2 (P<0.01). No statistically significant difference in the corneal higher-order aberrations was found between the two groups (P>0.05). However, the ocular higher-order aberrations in group 2 were significantly greater than in group 1 (P<0.05).
Conclusion
At 6 months postoperatively, both AcrivaUD Reviol BB MFM 611 IOL and AcrivaUD Reviol BB MF 613 IOL achieved excellent visual and refractive outcomes. The multifocal IOL model with plate haptic design resulted in better optical performances than that with the modified-C haptic design.
... Others have offered that intentional current-based damage serves as a barrier to additional current deposition without demonstrating damage efficacy. 20 Still others utilize current to create ionizing electromagnetic radiation associated with high temperature plasma formation, [36][37][38][39] which has raised further concerns regarding iatrogenic chondrocyte DNA fragmentation and nuclear condensation that can induce apoptosis, 40 cellular senescence, 41 decreased 42 progenitor cell populations, [43][44][45][46][47] diminished cellular differentiation potential, 42 and altered extracellular matrix structure and production. 48 Additional effects of ionizing electromagnetic radiation on chondrocyte behavior important for in situ healing responses 49-57 remain worrisome. ...
Safe articular cartilage lesion stabilization is an important early surgical intervention advance toward mitigating articular cartilage disease burden. While short-term chondrocyte viability and chondrosupportive matrix modification have been demonstrated within tissue contiguous to targeted removal of damaged articular cartilage, longer term tissue responses require evaluation to further clarify treatment efficacy. The purpose of this study was to examine surface chondrocyte responses within contiguous tissue after lesion stabilization.
Nonablation radiofrequency lesion stabilization of human cartilage explants obtained during knee replacement was performed for surface fibrillation. Time-dependent chondrocyte viability, nuclear morphology and cell distribution, and temporal response kinetics of matrix and chaperone gene transcription indicative of differentiated chondrocyte function were evaluated in samples at intervals to 96 hours after treatment.
Subadjacent surface articular cartilage chondrocytes demonstrated continued viability for 96 hours after treatment, a lack of increased nuclear fragmentation or condensation, persistent nucleic acid production during incubation reflecting cellular assembly behavior, and transcriptional up-regulation of matrix and chaperone genes indicative of retained biosynthetic differentiated cell function.
The results of this study provide further evidence of treatment efficacy and suggest the possibility to manipulate or induce cellular function, thereby recruiting local chondrocytes to aid lesion recovery. Early surgical intervention may be viewed as a tissue rescue, allowing articular cartilage to continue displaying biological responses appropriate to its function rather than converting to a tissue ultimately governed by the degenerative material property responses of matrix failure. Early intervention may positively impact the late changes and reduce disease burden of damaged articular cartilage.
... As the pulses do not exceed 100 µs in duration the heat diffuses to the surrounding tissue only up to 7 µm inducing only little collateral thermal damage. [13] The aim of this study was to investigate in-vitro efficacy and safety of tissue ablation with the PEAK-fc knife to reduce the amount of graft choroidal tissue in RPE-choroid translocation surgery. ...
To test the microablation of excess graft choroidal tissue with the pulsed electron avalanche knife (PEAK-fc) in an in-vitro model of autologous retinal pigment epithelium (RPE)-choroid translocation.
Choroidal tissue of porcine RPE-choroid explants was ablated with the PEAK-fc. Tissue morphology was assessed by light microscopy (LM) and scanning electron microscopy (SEM). The amount of ablated choroidal tissue was analysed as a function of three PEAK-fc parameters: (1) amplitude of biphasic voltage (70-100%); (2) distance between choroidal tissue and tip of the PEAK-fc (0-300 μm); and (3) exposure time (2-8 s).
LM and SEM showed a smooth plain within the ablation area with well defined cutting edges and preserved adjacent tissue structure. The mean amount of ablated tissue correlated linearly with applied voltage (range 79-120 μm, r=0.34) and distance between choroidal tissue and PEAK-fc tip (range 10-100 μm, r=0.74). The mean amount of ablated tissue increased with exposure time between 2 and 4 s (36-88 μm, r=0.4) and remained constant between 4 and 8 s.
The PEAK-fc accurately microablates choroidal tissue in-vitro. The adjacent choroidal tissue structure and Bruch's membrane are preserved. Patient studies are required to test the PEAK-fc in RPE-choroid translocation surgery.
... The argon plasma, which is electrically neutral, releases both thermal and kinetic energy upon contact with tissue, and thus has more than one mode of action. [23][24][25][26] The mechanical agitation likely dissipates any liquid in the operative field (thus ensuring a dry surface required for more effective cutting) and the thermal energy cuts the tissues and rapidly coagulates a thin, superficial layer of tissue which minimizes bleeding and lymphatic ooze. Although the tip of the probe can reach temperatures of around 450 8C, the small area of heat dissipation results in very little collateral damage (Figures 4 and 5). ...
Non‐thermal gas plasmas (NTGPs) are a promising emergent medical technology. a Unlike thermal plasmas, they generate a complex room temperature mix of reactive species which interact with tissues. The characterization of candidate plasmas and their interaction with tissues has shown that they produce a variety of broadly dose dependent effects ranging from fibroblast proliferation to angiogenesis and bacterial destruction. These findings, supported by recent experiments using skin models, suggest that NTGP's could potentially play an important role in both decontaminating acute and chronic wounds and accelerating healing. However, important issues over toxicological and environmental safety remain unanswered and a number of regulatory and technical hurdles will need to be overcome before a NTGP medical device is released.
magnified image
... In certain settings, highlevel energy radiofrequency devices can be configured to produce water vapor preferentially through very rapid and intense resistive heating, overcoming the high heat of vaporization at the treatment site (Floume et al, 2010;Thompson et al, 2009;Wood et al, 2005). Coincident with this method, the far-field time-varying electromagnetic forces of these devices deliver energy quanta able to generate charged plasma particles within the water vapor cloud (Priglinger et al, 2007;Stadler et al, 2001;Graham and Stadler, 2007). This ionizing electromagnetic radiation can induce an electron cascade, which operates over very short distances (Debye sphere) and with electron temperatures of several thousand degrees Celsius, to produce therapeutic molecular disintegration of biologic tissues as its action decays into heat. ...
... In the presence of charged species like salts, this temperature driven phase transition process from rapid resistive heating at the electrode is slowed by 3-4 times, which further increases the amount of energy required to reach phase transition (Fayer et al, 2009;Nucci and Vanderkooi, 2008). Once phase transition occurs, water vapor and other elements can be ionized by the electromagnetic forces associated with this radiofrequency energy level required to drive the heating process to phase transition (Priglinger et al, 2007;Stadler et al, 2001;Graham and Stadler, 2007). ...
The effects produced by surgical devices that deploy an electrical circuit between electrodes are dependent on the nature of electrical work performed upon the conduc-tive media in and around biologic tissues. Because this conductive media is water-based, this study characterizes the effects that non-ablation radiofrequency energy exerts upon saline interfacing media typi-cally encountered during surgical applica-tions. Non-ablation radiofrequency surgi-cal devices were deployed in a bulk 0.9% sodium chloride solution at 300 mOsm/L at 20 o C. During energy delivery, temper-ature and pH changes; gaseous species production, gas condensation behavior, and gas generation dynamics; and ionized charged particle generation were measured in the region of a constrained primary reac-tion zone surrounding an active electrode. Saline temperature change demonstrated three functional domains commensurate with a decrease in pH at steady-state at the constrained primary reaction zone without changes to the bulk fluid. Gas chromatog-raphy, thermal conductivity detector, and flame ionization detection evaluations mea-sured a uniform 2:1 ratio of hydrogen and oxygen comingled non-condensable gas production indicative of split water with-out heat transfer or gas generation dynam-ics of water vapor. The presence of ionized charged particles was not detected. These results allowed formulation of a stoichio-metric model depicting a repetitive mo-lecular energy conversion loop from water under non-ionizing electromagnetic forces. Non-ablation radiofrequency applications utilize the energy from the molecular bonds of interfacing media water to perform sur-gical work without delivering ionizing elec-tromagnetic radiation.
New techniques in plasma cutting cause far less collateral damage at incision surfaces and a higher surgical precision than previous methods.
In pediatric cataracts, the capsulorhexis decides the type and the site of IOL insertion. Even in normal capsule, the rhexis is difficult, presence of plaques or fibrosis makes it even more challenging.
