Aspiration Of Cortex Research Articles

Automated Capsular Decompression to Avoid Argentinian Flag Sign in Intumescent Cataract.

We describe an alternative automated technique that consists of simultaneous anterior capsule puncture and decompression of the capsular bag by using an insulin needle attached to the aspiration tubing of the phacoemulsification device to prevent the occurrence of the "Argentinian Flag sign" during capsulorhexis in intumescent cataract. Instituto de Olhos de Assis and Center of Specialties Hoftalmed, located in the state of São Paulo, Brazil. Prospective interventional study. Eighty-eight eyes of 88 patients with white or intumescent cataracts were included in this study. Routine clear cornea incision, capsule staining with trypan blue, intracameral anesthesia, and ophthalmic viscoelastic device were used before the procedure. A 26-gauge needle was connected to the phacoemulsification aspiration tubing using a double male Luer connector for irrigation, and aspiration was inserted into the anterior chamber through a new paracentesis incision with the bevel facing down. Immediately after insertion, automated aspiration of the liquefied cortex was performed to remove anterior intralenticular material and achieve capsular decompression. Compression of the nucleus with the needle tip was performed to remove any liquefied material trapped between the posterior surface of the nucleus and the posterior capsule. All surgeries were performed using the same phacoemulsification and parameters. The rate of complete continuous capsulorhexis was observed and noted. No complications were observed in any of the cases. A single-stage, continuous, and well-centered capsulorhexis was achieved in 100% of cases. We conclude that a simultaneous puncture and decompression of the capsular bag using an insulin needle attached to the aspiration tubing of the phacoemulsification machine effectively avoided the "Argentinian Flag sign" in intumescent cataract surgery.

Image sharpening algorithms improve clarity of surgical field during 3D heads-up surgery

BackgroundImage-sharpening algorithms with color adjustments enable real-time processing of the surgical field with a delay of 4 msec for heads-up surgery using digital three-dimensional displays. The aim of this study was to investigate the usefulness of the algorithms with the Artevo 800® digital microscope.MethodsSeven vitreoretinal surgeons evaluated the effects of image-sharpening processing on the clarity of the surgical field with the Artevo 800® system that is used for cataract and vitreous surgeries. The scorings were made on a 10-point scale for anterior capsulotomy, phacoemulsification, cortex aspiration, core vitrectomy, and peeling of an epiretinal membrane or an internal limiting membrane. In addition, the images during the internal limiting membrane peeling were processed with or without color adjustments. We also evaluated the skewness (asymmetry in the distribution of the pixels) and kurtosis (sharpness in the distribution of the pixel) of the images to evaluate the contrast with each intensity of image-sharpening.ResultsOur results showed that the mean visibility score increased significantly from 4.9 ± 0.5 at 0% (original image) to 6.6 ± 0.5 at 25% intensity of the image-sharpening algorithm (P < 0.01). The visibility scores of the internal limiting membrane increased significantly from 0% (6.8 ± 0.3, no color adjustments) to 50% after the color adjustments (7.4 ± 0.4, P = 0.012). The mean skewness decreased significantly from 0.83 ± 2.02 at 0% (original source) to 0.55 ± 1.36 at 25% intensity of the image-sharpening algorithm (P = 0.01). The mean kurtosis decreased significantly from 0.93 ± 2.14 at 0% (original image) to 0.60 ± 1.44 at 25% intensity of the image-sharpening algorithm (P = 0.02).ConclusionsWe conclude that the image-sharpening algorithms can improve the clarity of the surgical field during 3D heads-up surgery by decreasing the skewness and kurtosis.Trial registrationThis was a prospective clinical study performed at a single academic institution, and the procedures used were approved by the Institutional Review Committee of the Kyorin University School of Medicine (reference number, 1904). The procedures also conformed to the tenets of the Declaration of Helsinki.

Vacuum-assisted cortex removal - A novel change to the tradition.

In developing countries, manual small-incision cataract surgery (MSICS) has surfaced as the cost-effective alternative to phacoemulsification. The Simcoe irrigation-aspiration cannula was developed nearly 40 years ago and is still the most frequently employed tool for cortex aspiration. Although it stands unsurpassed, here we attempt to introduce an addition to the existing Simcoe cannula to achieve a dynamic and controlled vacuum with the added advantage of less physical strain and an effective volume of aspiration. The vacuum-assisted cortex removal device is based on a simple spring action mechanism, where the relaxation of the spring pushes the plunger up and thereby generates a controlled vacuum.

Inside-out and outside-in: Tips and tricks in posterior lenticonus.

Posterior lenticonus is a congenital condition characterized by the thinning and bowing of posterior lenticular capsule. Cataract develops when normal intra-lenticular pressure bulges the posterior capsule at the circumscribed portion of inherent thin posterior lens capsule, leading to derangement of lamellar lens fibers. This condition poses a surgical challenge as the presentation varies from thin, bulging posterior capsule to large, pre-existing posterior capsular dehiscence. This video highlights the tips for the surgical management of various scenarios of posterior lenticonus. In this video, tips for surgical management of various scenarios of posterior lenticonus are illustrated. Intraoperatively, ruptured posterior capsule is suspected by the presence of a fish-tail sign. The anterior capsulotomy is relatively easier in a flatter anterior lens capsule, owing to reduced intra-lenticular pressure. Hydro-dissection is avoided to prevent extension of pre-existing posterior capsular dehiscence or creation of rupture in a thinned-out capsule. The peripheral lens cortex aspiration is initiated first, followed by in each quadrant. In a presence of ruptured posterior capsule by vigilant inspection at this stage, the surgeon should change the direction of lens matter aspiration by aspirating the central lenticular matter first, followed by peripheral cortex like "inside-out". In absence of posterior capsule dehiscence, peripheral cortex is aspirated first, followed by central lens matter aspiration like "outside-in". Adequate anterior vitrectomy is performed until there are no vitreous tags. In the presence of pre-existing posterior capsular defect, the lens matter is aspirated from the center (inside-out), whereas in the absence of capsular defect, the lens matter is aspirated from the periphery (outside-in). https://youtu.be/8G6BCbFwr8Q.

Three Cases of Intraoperative Acute Fluid Misdirection Syndrome during Cataract Surgery

Purpose: We report the management of three cases of intraoperative acute fluid misdirection syndrome during cataract surgery.Case summary: Cataract surgery was performed in one eye of an 82-year-old woman with pseudoexfoliation syndrome, one eye of an 80-year-old man with end-stage glaucoma, and both eyes of a 72-year-old man with pseudoexfoliation syndrome. In the first two cases, the capsular bag space decreased during cortex aspiration and after removal of the cortex, respectively. After intravenous mannitol and intake of oral acetazolamide, the intraocular lens was successfully inserted in the first two cases on the same day. In the third case, after first removing the nucleus and cortex of the right eye, the capsular bag space decreased and an intraocular lens was carefully inserted. No intraoperative complications were seen during the left eye operation. One month after the operation, the best-corrected visual acuity had improved and the intraocular pressure was within normal limits for all three cases.Conclusions: A relatively shallow chamber, pseudoexfoliation, zonular laxity, and use of high molecular weight ophthalmic viscosurgical devices may cause acute fluid misdirection syndrome during cataract surgery. Pars plana vitrectomy may be required. However, intravenous high osmotic agent treatment should be attempted first, followed by intraocular lens insertion on the same day.

Study on dependence of phacoemulsification of senile cataract parameters on features of hydrodissection

The aimwas to study the dependence of senile cataract phacoemulsification (PE) parameters on hydrodissection (HD) features.&#x0D; Materials and methods.64 patients (64 eyes) who underwent PE of senile cataract using either viscodissection (VD) (main group) or regular HD (control group). Time parameters VD and HD duration, cortex aspiration, and total time of PE, along with calculation of mean volume of BSS in both groups were studied.&#x0D; Results.It took 1.8 times more time to perform VD compared to HD duration. The cortex aspiration step required 2.4 times less time in the eyes of main group in comparison with control group, as 10 eyes (31.2%) of the main group had spontaneous full cortex evacuation through ultrasound tip at epinucleus removal. Other 22 eyes (78.8%) of the main group needed aspiration of cortex, which occupied 1/61/3 capsule circumference. Though surgery time was comparable in both groups, mean volume of BSS spent was justifiably 1.5 times higher in the control group.&#x0D; Conclusion.Performed analysis showed that VD is an effective method which provides optimization of PE of senile cataract. Use of VD allowed exclusion of cortex aspiration in 31.2% of eyes in the main group and decrease of its duration by 2.4 times in comparison with the control group.

Структура нейроэпителия и микроангиоархитектоника макулярной области после факоэмульсификации с использованием ультразвуковой системы для аспирации кортикальных масс

«Российская офтальмология онлайн» - электронное информационное издание, создается с 1 марта 2010 года под эгидой Российского общества офтальмологов. Основная задача проекта - научно-информационная поддержка специалистов в области офтальмологии.

Cortical aspiration - The "POPS" technique.

In the present study, we describe a step-by-step technique for cortex aspiration during cataract surgery- POPS (positioning, occlusion, posterior displacement, and swiping). Firstly, the aspiration probe is positioned under the bulk of cortical fibers beyond the capsulorhexis margin. Subsequently, the aspiration port is occluded with minimal vacuum, and the occluded port is displaced posteriorly to detach the cortical fibers off the anterior capsule. Now, tangential, arc-like swiping movements are performed while gradually increasing vacuum at the same time. The fibers are brought to the center and finally aspirated. This allows complete removal of the equatorial fibers and lens epithelial cells (LEC) with the least stress to the capsulozonular complex. Unlike the conventional technique, which involves the radial pull of cortical fibers, in this technique, there is swiping and posterior displacement of the cortical fibers before pulling towards the center and aspirating. We believe this technique will ensure safer, more effective cortical and LEC removal, reducing zonular stress.

The medial frontal cortex contributes to but does not organize rat exploratory behavior

Animals use multiple strategies to maintain spatial orientation. Dead reckoning is a form of spatial navigation that depends on self-movement cue processing. During dead reckoning, the generation of self-movement cues from a starting position to an animal’s current position allow for the estimation of direction and distance to the position movement originated. A network of brain structures has been implicated in dead reckoning. Recent work has provided evidence that the medial frontal cortex may contribute to dead reckoning in this network of brain structures. The current study investigated the organization of rat exploratory behavior subsequent to medial frontal cortex aspiration lesions under light and dark conditions. Disruptions in exploratory behavior associated with medial frontal lesions were consistent with impaired motor coordination, response inhibition, or egocentric reference frame. These processes are necessary for spatial orientation; however, they are not sufficient for self-movement cue processing. Therefore it is possible that the medial frontal cortex provides processing resources that support dead reckoning in other brain structures but does not of itself compute the kinematic details of dead reckoning.

Adult hemiparkinsonian rats do not benefit from tactile stimulation

Tactile stimulation (TS) applied to adult rats after cortical injury (medial frontal cortex aspiration or sensorimotor pial stripping stroke model) has been previously shown to ameliorate behavioral impairments and to improve morphological parameters like dendritic length of prefrontal cortical neurons (Gibb et al., 2010). The purpose of this study was to examine the effect of TS on healthy and hemiparkinsonian adult rats. Therefore, the animals received TS for 14 days and 15min three times daily. At different time points rats were tested in various behavioral tests (amphetamine-induced rotation, cylinder test, staircase test). Finally, rats were sacrificed, their brains removed, and processed for Golgi-Cox analyses, tyrosine hydroxylase immunohistochemistry and quantitative RT-PCR. We found that the striatal 6-OHDA lesion itself induced a long-term increase of astroglial Fgf2 transcript levels, but was not further increased by TS. In contrast TS applied to healthy rats elicited a transient short-term increase of Fgf2 in the striatum and Bdnf, Grin1, and Fgf2 in the hippocampus. Moreover, behavioral and histological analyses do not support a beneficial effect of TS for hemiparkinsonian rats, applied for two weeks starting one day after partial striatal 6-OHDA lesion.

Femtosecond Laser-Assisted Cataract Surgery Without Ophthalmic Viscosurgical Devices

To describe a technique for performing femtosecond laser-assisted cataract surgery without the use of ophthalmic viscosurgical devices (OVDs). After laser pretreatment, the anterior chamber is stabilized with balanced salt solution during lens and cortex aspiration. A preloaded intraocular lens is implanted under irrigation. In 23 eyes undergoing surgery without the use of OVDs, no complications were observed within a 1-month follow-up period. The time for surgery and the amount of fluid that went into the eye were similar to those of a standard procedure. There was no remarkable increase in intraocular pressure or corneal thickness. All patients achieved a significant increase in corrected distance visual acuity after surgery. The significant reduction of phacoemulsification use after femtosecond laser application might render the use of OVDs obsolete in many cases.

Vitrectorhexis and lens aspiration with posterior chamber intraocular lens implantation in spherophakia

We describe a technique that uses the vitrector to perform successful lens aspiration and posterior chamber intraocular lens (IOL) implantation in children with spherophakia and anterior lens subluxation. After an anterior chamber maintainer is placed, the ocutome is introduced through a limbal incision to perform a circular vitrectorhexis to avoid excessive manipulation of the unstable lens followed by gentle cortex aspiration. A foldable IOL is injected into the sulcus (3-piece IOL) or bag (1-piece IOL) if the capsule is sufficiently stable. Through a pars plana incision, the ocutome is then used to perform a posterior capsulotomy to prevent late posterior capsule opacification. In our patient, sulcus IOL placement was more stable than in-the-bag placement. Neither author has a financial or proprietary interest in any material or method mentioned.

Hybrid bimanual technique for aspiration of residual cortex

Editor, Aspiration of residual cortical matter, especially if located in the subincisional area, can pose a challenge to the cataract surgeon. Various methods have been described to aid the aspiration of residual cortical matter, including use of bimanual IA systems, J-shaped cannulas (Dewey 2002) and transparent irrigation cannulas (Shimada et al. 2002). We describe a hybrid bimanual technique of aspiration of residual cortical matter that uses a combination of the coaxial and bimanual IA hand pieces and averts the requirement of an additional side port. An informed consent was obtained from all the patients undergoing cataract surgery. The study followed the tenets of the Declaration of Helsinki. Two incisions are made at the start of cataract surgery. A 2.75-mm main port is made using a 2.75-mm blade (Alcon Labs, Fort Worth, TX, USA) for the coaxial phacoemulsification probe (Infiniti System, Alcon Labs, USA) and a side port made two clock hours away from the main port with a 20G MVR blade (Alcon Labs). Following the completion of nuclear and epinuclear phacoemulsification, aspiration of cortical matter is begun using the traditional coaxial hand piece. The hybrid bimanual technique may be used if the surgeon is unable to completely aspirate the cortical matter. The coaxial IA probe connected only to the irrigation tubing is introduced into the anterior chamber through the 2.75-mm main incision. The aspiration hand piece of the bimanual system (Appasamy, India) is inserted in the anterior chamber through the 20G side port. The bimanual aspirating hand piece is used to aspirate the remaining cortical matter (Fig. 1). The tip of the coaxial hand piece is kept just below the interior lip of the valve. This allows for better visualization of the aspiration port of the aspirating hand piece. Hybrid Bimanual irrigation–aspiration being performed using the coaxial hand piece for irrigation and bimanual aspiration hand piece for aspiration. We used this technique in 27 eyes of 27 patients with residual cortex. Cortex could be successfully aspirated in 26 of 27 eyes with the use of the modified technique. One eye that had extensive cortex under the area where the side port was made required conversion to the standard technique of bimanual irrigation and aspiration (IA). No posterior capsular rupture occurred in any of the cases. Residual cortex, especially located in the subincisional area, can pose challenges to the surgeon. Bimanual irrigation and aspiration can greatly ease the removal of residual cortical matter. However, if the surgeon uses a single side port for phacoemulsification, an additional side port needs to be created during the surgery to enable bimanual IA. Our technique obviates the requirement for an additional side port. When the traditional bimanual IA system is used through the two side ports, the larger, main port tends to leak during IA, as it is not occluded by the hand piece. This may lead to surge and instability of the anterior chamber. As the main port is effectively occluded by the coaxial hand piece during IA using our technique, the anterior chamber is more stable during irrigation and aspiration. The only drawback that we experienced with our technique is the occasional inadequate visualization of subincisional cortical matter in the area below the side port as compared to the use of a traditional bimanual IA technique. In such cases, one can make a second side port and shift to the standard bimanual IA technique. In conclusion, the hybrid bimanual technique is a useful modification that can be safely used for aspirating the residual cortical matter during cataract surgery. It combines the benefits of the traditional bimanual IA system with that of the coaxial IA system and at the same time circumvents the need for creation of the second side port.

Modified sutureless small-incision non-phacoemulsification extracapsular cataract surgery in high myopia with cataract

Objective To evaluate the clinical efficiency and safety of the modified sutureless small-incision non-phacoemulsification extracapsular cataract surgery in high myopia. Methods This study comprised 56 highly myopic cataract patients (70 eyes). Continuous curvilinear capsulorhexis, hydrodissection and hydrodelineation, assisting nucleus-chop, and irrigation/aspiration procedures were performed through an extra constructed auxiliary incision to maintain more stable anterior chamber and facilitate the manipulation during surgery. Furthermore, low flow and the protection of viscoelastic material made cortex aspiration thoroughly and more safely. Results 58 axial length ＜ 30 mm eyes, the best correctted visual acuity (BCVA) exceeded 0.5 in 45 eyes (80.36%) at 1 month of follow-up. Among 12 axial length≥30 mm eyes, the BCVA exceeded 0. 3 in 7 eyes (58.33%). Corneal curvature kept unchangeable after surgery. No intraoperative or postoperative complications such as posterior capsule rupture, zonules as well as iris and cornea injury occurred. Conclusion The modified sutureless small-incision non-phacoemulsification extracapsular cataract surgery was safe and with more efficiency in high myopia. Key words: high myopia; modified; small-incision; non-phacoemulsification

Double Aspiration/Single Irrigation System for Bimanual Lens Cortex Removal in Cataract Surgery

The authors describe a bimanual double aspiration/single irrigation system (DASIS) for cataract surgery that efficiently and safely performs aspiration of the entire cortex, including subincisional space. DASIS uses standard and common instruments such as an irrigation/aspiration handpiece in one hand and a single-aspiration handpiece in the other, joined with a short silicone tube using a three-way stopcock. DASIS allows access to 360° of the cortex without a hand exchange, reducing wound leakage and maintaining chamber stability.

Tactile stimulation promotes motor recovery following cortical injury in adult rats

Tactile stimulation has been reported to be effective as a treatment for inducing growth in premature human babies and infant rats and for improving functional recovery after brain injury in infant rats. We wondered if the behavioral impairments following injury in adulthood would show similar improvements with tactile stimulation. To test this hypothesis, rats were given either bilateral medial frontal cortex aspiration lesions or a unilateral focal stroke produced in the sensorimotor cortex using the pial stripping technique. In both conditions, rats that were designated to the tactile stimulation treatment group received the stimulation for one week before the surgery to accustom them to the stimulation procedure and then two weeks postoperatively. After a three-week recovery period, the animals with frontal damage were tested in a tray-reaching task. Animals with sensorimotor cortex damage were tested in a single pellet reaching task. Following behavioral testing brains were processed for Golgi-Cox analyses. Marked improvement was found in motor performance in the lesion-tactile stimulation animals regardless of the nature of the cortical injury. The observed behavioral recovery was associated with an increase in dendritic length in pyramidal cells adjacent cortex in the frontal operates and in the intact sensorimotor cortex in the stroke animals. Taken together, these data show tactile stimulation can improve motor performance in adult animals and the improvement is correlated with dendritic sprouting. This finding could have implications for therapy in humans following stroke.

Anterior Chamber Maintainer (ACM): A useful aid in small incision cataract surgery

In order to promote the use of Anterior Chamber Maintainer (ACM), a prospective intervention study was carried out. The ACM was introduced in the anterior chamber at various steps of surgery in 82 patients. Sixty one patients under went manual small incision cataract surgery (MSICS) and 21 patients phacoemulsification. Forty four males & 38 females were included in the study. Construction of sclero-corneal tunnel and aspiration of sub incisional cortex could be done with relative ease with the use of ACM. Thirty eight patients (46.34%) unaided and 56 patients (68.29%) aided with pinhole had V/A 20/60 or better (mode 20/30) on the first post operative day. Use of ACM leads to better cortical cleaning and lesser postoperative uveal inflammation. It was helpful even with phakoemulsification and during secondary surgeries.

Sensorimotor cortex aspiration: A model for studying Wallerian degeneration-induced glial reactivity along the entire length of a single CNS axonal pathway

Although there are some similarities in the molecular and cellular pattern of Wallerian degeneration in the PNS and CNS, in the CNS the removal of axonal and myelin debris by microglia and astrocytes is not very efficient and occurs over a much longer time frame than seen in a peripheral nerve. Several animal models have been used to study Wallerian degeneration-induced glial reactivity in the CNS and PNS. Although these models have clarified some aspects of the mechanisms underlying the differential glial cell responses in the PNS and CNS, they do not lend themselves easily to deciphering the mechanisms governing the location and extent of Wallerian degeneration-induced CNS glial reactivity. The present study develops a new animal model that entails destruction of the left sensorimotor cortex of adult rats to induce Wallerian degeneration within the total length of a fiber tract (i.e. the dorsal corticospinal tract) that extends all the way from the cerebral cortex to the sacral level of the spinal cord. Since the axonal degeneration in the ventral medulla and dorsal funiculus of the spinal cord would be confined to the corticospinal tract, it was predicted the glial reactivity would also be restricted to this fiber tract. Three distinct proximal–distal levels of this pathway were examined to determine the morphology, distribution and immunophenotype of microglia and astrocytes between 1 day and 16 weeks after sensorimotor cortex aspiration. As expected, there was a proximal to distal gradient in the appearance of glial reactivity along the length of the pathway, with the microglial reactivity being seen as early as 3 weeks in the left pyramid, and by 4 weeks (i.e. at C6) and 6 weeks (i.e. at T11) in the right dorsal corticospinal tract. Astrocytic reactivity lagged behind that of the microglial response at each level of the pathway. The microglial and astrocytic reactivity persisted up to 16 weeks after cortical injury, which was the longest survival time studied. The sensorimotor cortex aspiration model should prove extremely useful in deciphering the molecular mechanisms controlling Wallerian degeneration-induced CNS glial reactivity and in determining the relative role of astrocytes vs microglia in clearance of axonal and myelin debris.

Inhibition of surgically induced miosis and prevention of postoperative macular edema with nepafenac

To evaluate the effectiveness of prophylactic administration of nepafenac 0.1% in maintaining mydriasis and in preventing postoperative macular edema following cataract surgery. This was a prospective, randomized, single-masked comparative study in 60 patients undergoing phacoemulsification cataract surgery. Patients were randomized to either the nepafenac or the control group. Nepafenac was administered 3 times daily 1 day before surgery and continued for 6 weeks. The control group received tobramycin-dexamethasone treatment only. Trans-operative mydriasis was measured before surgery, after nuclear emulsification, following cortex aspiration, and at the conclusion of surgery. Macular optical coherence tomography determined central foveal thickness (FT) and total macular volume (TMV) before surgery and at 2 and 6 weeks after surgery. All patients received tobramycin-dexamethasone for 2 weeks after surgery. The difference in mean pupil size, at the end of surgery, between the control group (6.84 +/- 0.93 mm) and the nepafenac group (7.91 +/- 0.74 mm) was statistically significant (p < 0.001). There were no significant differences in FT values between the two groups at any time point; however, TMV at 2 and at 6 weeks was statistically significantly different (p < 0.001), with higher TMV in the control group. Prophylactic use of nepafenac was effective in reducing macular edema after cataract surgery and in maintaining trans-operative mydriasis.

Addition of fornix transection to frontal‐temporal disconnection increases the impairment in object‐in‐place memory in macaque monkeys

Both frontal-inferotemporal disconnection and fornix transection (Fx) in the monkey impair object-in-place scene learning, a model of human episodic memory. If the contribution of the fornix to scene learning is via interaction with or modulation of frontal-temporal interaction − that is, if they form a unitary system − then Fx should have no further effect when added to frontal-temporal disconnection. However, if the contribution of the fornix is to some extent distinct, then fornix lesions may produce an additional deficit in scene learning beyond that caused by frontal-temporal disconnection. To distinguish between these possibilities, we trained three male rhesus monkeys on the object-in-place scene-learning task. We tested their learning on the task following frontal-temporal disconnection, achieved by crossed unilateral aspiration of the frontal cortex in one hemisphere and the inferotemporal cortex in the other, and again following the addition of Fx. The monkeys were significantly impaired in scene learning following frontal-temporal disconnection, and furthermore showed a significant increase in this impairment following the addition of Fx, from 32.8% error to 40.5% error (chance = 50%). The increased impairment following the addition of Fx provides evidence that the fornix and frontal-inferotemporal interaction make distinct contributions to episodic memory.