A novel simulation model for penetrating keratoplasty.
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ABSTRACT:
SUBMITTER: Solyman O
PROVIDER: S-EPMC8837378 | biostudies-literature | 2021 Dec
REPOSITORIES: biostudies-literature
Publications
A novel simulation model for penetrating keratoplasty.
Solyman Omar O Matharu Kanwal S KS Wang Yvonne Y Weikert Mitchell P MP
Indian journal of ophthalmology 20211201 12
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Project description:ObjectiveThis study sought to compare graft survival, graft rejection and the visual acuity outcome of endothelial keratoplasty (EK) with repeat penetrating keratoplasty (PK) after failed PK.MethodsA systematic literature search with subsequent screening of the identified articles was conducted to obtain potentially eligible randomized clinical trials (RCTs) and comparative cohort studies. To assess the methodological quality of the included studies, the Jadad Scale or Newcastle-Ottawa Scale (NOS) was used based on the study design. To calculate the pooled odds ratios (ORs) for graft survival, graft rejection and the visual acuity outcome with 95% confidential intervals (CIs), a fixed- or random-effects model was applied based on the heterogeneity across studies.ResultsFour comparative cohort studies (n = 649 eyes) comparing the outcome of EK with repeat PK after failed PK were included in this review. These studies were considered high quality, with NOS scores ranging from 6 to 9. The EK group showed a significantly lower risk of graft rejection than the repeat PK group [0.43 (95% CI: 0.23-0.80, P = 0.007)]. In addition, no significant differences were observed in a comparison of graft survival and visual acuity (P values ranged from 0.81 to 0.97 using the Der-Simonian and Laird random-effects model).ConclusionsAs an alternative to repeat PK, EK after failed PK allows for potential reduction of the risk of graft rejection; however, it does not appear to confer a significant advantage in graft survival or visual acuity.
| S-EPMC5495398 | biostudies-literature
Project description:To investigate the incidence, causes, occurrence time, and range of wound and outcomes of wound dehiscence in patients treated by penetrating keratoplasty (PK) or lamellar keratoplasty (LK).We retrospectively reviewed medical records of keratoplasty in Shandong Eye Hospital from January 2006 to June 2017. Thirty-one eyes of 30 patients had sustained wound dehiscence (WD) after surgical treatment. The surgical type, causes, occurrence time, extent of the wound, treatment, and outcomes were recorded.The study population consisted of 26 men and 4 women. The mean age at the occurrence of WD was 44.6 years old (range: 12-78 years), and the mean time from keratoplasty to WD was 45.9 months (range: 1-204 months). WD occurred in 23 eyes (23/1385, 1.66%) after PK and 8 eyes (8/1632, 0.49%) after LK (p < 0.05). Twenty-seven eyes (27/31, 87.0%) had trauma-induced dehiscence. The mean range of dehiscence was 5.5 o'clock. The vision ranged from 20/50 to light perception after wound suture. The eyes receiving LK had fewer serious complications than PK.Compared with LK, PK seems to be more prone to result in wound dehiscence. The WD after LK may be less severe. The visual acuity after treatment of WD can be worse in the eyes with PK than LK.
| S-EPMC6079506 | biostudies-literature
Project description: Not available
| S-EPMC10714035 | biostudies-literature
Project description:PurposeThis study aims (1) to investigate the feasibility of robot-assisted penetrating keratoplasty (PK) using the new Da Vinci Xi Surgical System and (2) to report what we believe to be the first use of this system in experimental eye surgery.MethodsRobot-assisted PK procedures were performed on human corneal transplants using the Da Vinci Xi Surgical System. After an 8-mm corneal trephination, four interrupted sutures and one 10.0 monofilament running suture were made. For each procedure, duration and successful completion of the surgery as well as any unexpected events were assessed. The depth of the corneal sutures was checked postoperatively using spectral-domain optical coherence tomography (SD-OCT).ResultsRobot-assisted PK was successfully performed on 12 corneas. The Da Vinci Xi Surgical System provided the necessary dexterity to perform the different steps of surgery. The mean duration of the procedures was 43.4 ± 8.9 minutes (range: 28.5-61.1 minutes). There were no unexpected intraoperative events. SD-OCT confirmed that the sutures were placed at the appropriate depth.ConclusionsWe confirm the feasibility of robot-assisted PK with the new Da Vinci Surgical System and report the first use of the Xi model in experimental eye surgery. Operative time of robot-assisted PK surgery is now close to that of conventional manual surgery due to both improvement of the optical system and the presence of microsurgical instruments.Translational relevanceExperimentations will allow the advantages of robot-assisted microsurgery to be identified while underlining the improvements and innovations necessary for clinical use.
| S-EPMC5482186 | biostudies-literature
Project description:PurposeThe purpose of this study was to investigate the clinical features, surgical outcomes, and prognostic factors of penetrating keratoplasty (PKP) after open globe injury (OGI).MethodsA retrospective review of all patients treated for OGI between January 2000 and July 2017 was conducted. Demographic, preoperative, perioperative, and postoperative data were collected for those who underwent PKP after OGI. The predictive value of each preoperative variable on graft failure was assessed using univariate and multivariable Cox proportional hazards models, and the predictive value of variables on post-PKP visual outcome was assessed using both univariate and multivariable logistic regression models. All eyes that underwent PKP after OGI were included unless they had less than 365 days of follow-up.ResultsForty-six eyes that underwent PKP met inclusion criteria. The median age was 46 years (interquartile range = 23.00-61.25), median follow-up was 78.5 months (interquartile range = 38.63-122.02), and 37 of 46 subjects (80.4%) were male. The observed 1- and 5-year graft survival estimates were 80.4% and 41.7%, respectively. Factors statistically associated with graft failure in multivariable analyses were rejection episode, hazard ratio (HR) = 3.29; retinal detachment (RD), HR = 3.47; and endophthalmitis, HR = 6.27. Fifteen of 42 eyes (35.7%) regained ambulatory vision (20/200 or better). The strongest predictors of vision worse than 20/200 at the last follow-up were RD, odds ratio (OR) = 43.88; graft rejection, OR = 12.42; and injury outside the workplace, OR = 25.05.ConclusionsDespite a high graft survival at 1 year, most of the patients did not regain ambulatory vision. Graft rejection, RD, and endophthalmitis were risk factors for graft failure. These factors should be considered when counseling patients regarding PKP after OGI.
| S-EPMC9555754 | biostudies-literature
Project description:PurposeThe purpose of this study was to establish a murine model of endothelial keratoplasty.MethodsEndothelial keratoplasty (EK) was performed using C57BL/6 donor and BALB/c recipient mice. The central endothelium and Descemet membrane were removed from the recipient cornea, and a 1.5-mm posterior lamellar donor graft was made adherent to the recipient cornea with a small amount of viscoelastic. Mice were followed through slitlamp microscopy postoperatively, and OCT was used to assess the cornea and anterior chamber and measure central corneal thickness. Histology and immunohistochemistry were performed to confirm graft adherence and endothelial cell morphology.ResultsSuccessfully attached EK grafts were visualized in all transplanted animals. Histology and immunostaining confirmed proper graft orientation and adherence, as well as the presence of donor endothelium on transplanted grafts. We observed maximal corneal edema in all animals at day 1 postoperatively which gradually subsided. EK graft survival was 97% at 8 weeks.ConclusionsIn this study, we describe a novel murine model for EK which we anticipate will enable detailed investigation into the cellular and molecular mechanisms involved in EK pathobiology.
| S-EPMC9805546 | biostudies-literature
Project description:PurposeTo present a case of hematocornea occurring in a post-penetrating keratoplasty (PK) eye and to report the outcomes of deep anterior lamellar keratoplasty (DALK) performed by simple stromal peeling.ObservationsA 45-year-old female presented with hematocornea in the left eye that previously underwent PK 26 months prior for keratoconus. Clinical examination revealed a dense reddish-brown opacity within the PK graft which was associated with deep corneal neovascularization. Over 6 months, intracorneal hemorrhage developed a rust-colored appearance with minimal clearing. DALK was performed using the stromal peeling technique for post-PK eyes. Briefly, a dense partially organized hemorrhage was identified at the natural plane of separation, as confirmed by ex vivo histologic examination; after peeling of the deep corneal stroma and evacuation of the intracorneal hemorrhage, the residual bed appeared akin to pre-Descemet's layer-Descemet membrane-endothelium complex. One year after DALK, the graft remained clear with ECD of 1034 cells/mm2.Conclusions and importanceIntracorneal hemorrhage is a rare but potentially sight-threatening complication following PK. Using the stromal peeling technique, DALK can be attempted to preserve functional endothelium in post-PK eyes. In the presence of a dense intracorneal hemorrhage, the spread of erythrocytic debris within the stroma can guide deep lamellar cleavage.
| S-EPMC9883201 | biostudies-literature
Project description:PurposeTo evaluate difference in therapeutic outcomes between deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP) for the clinical treatment of keratoconus.MethodsA comprehensive search was conducted in Pubmed, EMBASE, Cochrane Library, and Web of science. Eligible studies should include at least one of the following factors: best corrected visual acuity (BCVA), postoperative spherical equivalent (SE), postoperative astigmatism and endothelial cell count (ECC), central corneal thickness (CCT), graft rejection and graft failure, of which BCVA, graft rejection and graft failure were used as the primary outcome measures, and postoperative SE, astigmatism, CCT and ECC as the secondary outcome measures. Given the lack of randomized clinical trials (RCTs), cohort studies and prospective studies were considered eligible.ResultsSixteen clinical trials involving 6625 eyes were included in this review, including 1185 eyes in DALK group, and 5440 eyes in PKP group. The outcomes were analyzed using Cochrane Review Manager (RevMan) version 5.0 software. The postoperative BCVA in DALK group was significantly better than that in PKP group (OR = 0.48; 95%CI 0.39 to 0.60; p<0.001). There were fewer cases of graft rejection in DALK group than those in PKP group (OR = 0.28; 95%CI 0.15 to 0.50; p<0.001). Nevertheless the rate of graft failure was similar between DALK and PKP groups (OR = 1.05; 95%CI 0.81 to 1.36; p = 0.73). There were no significant differences in the secondary outcomes of SE (p = 0.70), astigmatism (p = 0.14) and CCT (p = 0.58) between DALK and PKP groups. And ECC in DALK group was significantly higher than PKP group (p<0.001). The postoperative complications, high intraocular pressure (high-IOP) and cataract were analyzed, fewer cases of complications occurred in DALK group than those in PKP group (high-IOP, OR 0.22, 95% CI 0.11-0.44, P<0.001) (cataract, OR 0.22; 95% CI 0.08-0.61, P = 0.004). And no cases of expulsive hemorrhage and endophthalmitis were reported.ConclusionThe visual outcomes for DALK were not equivalent to PKP. The rate of graft failure was similar between DALK and PKP. Fewer postoperative complications occurred in DALK group, indicating that compared with PKP, DALK has lower efficacy but higher safety.
| S-EPMC4310590 | biostudies-literature
Project description:PurposeTo theoretically compare corneal displacement and the von Mises (VM) stress distribution of deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) for keratoconus (KC) and to evaluate the effects of residual stromal thickness (RST) and intraocular pressure (IOP) on postoperative corneal biomechanics.MethodsWe performed DALK and PK simulations using Ansys by employing anisotropic nonlinear hyperelastic corneal material properties. We analyzed corneal displacement and VM stress in DALK and PK models under IOPs of 10, 15, 20, and 25 mmHg. We established two DALK models: The ideal-type DALK ensured that postoperative central corneal thickness was constant at 560 µm and the corneal graft thickness varied with RST. The clinical-type DALK ensured that corneal grafts had the same thickness (500 µm) regardless of RST. Then we analyzed the effects of RST and IOP on postoperative corneal displacement and VM stress.ResultsCorneal displacement and VM stress were lower in the DALK than in the PK model. In the ideal-type DALK model, an increase in RST was associated with increased deformation and decreased VM stress in the healing zone, except for a RST of 0 µm. In the clinical-type DALK model, deformation and VM stress in the healing zone decreased with an increase in RST, except for a RST of 0 µm.ConclusionsDALK showed more stability than PK. For the ideal-type DALK model, an increase in RST resulted in decreased postoperative corneal biomechanics in the healing zone. For the clinical-type DALK model, corneal deformation and VM stress decreased with an increase in RST, which provides numerical evidence for the design of corneal transplantation for patients with KC.Translational relevanceIn this computational modeling study, we first theoretically compared corneal biomechanics between DALK and PK for KC. Then, the effects of RST and IOP on postoperative corneal biomechanics were investigated. Our findings provide novel insights into the optimal design for corneal transplantation for patients with KC.
| S-EPMC8363774 | biostudies-literature
Project description:PurposeTo evaluate the outcome of eyes with large Descemet's membrane (DM) perforation during deep anterior lamellar keratoplasty (DALK).MethodsA retrospective, interventional case series of 12 eyes with completed DALK, despite DM perforation larger than 4 mm in its widest dimension. The main outcome measures included graft clarity, endothelial cell density (ECD), corrected distance visual acuity (CDVA), and DM detachment.ResultsThe mean age of patients was 26.8 ± 11.4 years. Preoperative pathology included keratoconus (n = 10), macular dystrophy (n = 1), and postmicrobial keratitis corneal scar (n = 1). The average size of DM perforation was 6.5 mm ± 1.3 mm. At the end of the follow-up period (median 15 months, range 6-53 months), the mean CDVA was 0.32 ± 0.09 logMAR and the mean ECD was 1830.8 ± 299.7 cells/mm2. Nine patients (75%) developed DM detachments postoperatively and was managed by intracameral air injection once in six eyes, and twice in three eyes. Other complications included persistent localized stromal edema at the site of DM defect in one eye and Urrets Zavalia syndrome in one eye.ConclusionCompleting DALK in eyes with large DM perforation provides good visual acuity, endothelial cell count and may be superior to penetrating keratoplasty regarding long-term graft survival if confirmed in future comparative studies.
| S-EPMC8365580 | biostudies-literature