Article Text
PDF
Abstract
Background/aims To characterise a sleeveless-extrusion cannula-based suction technique to levitate dislocated intraocular lens (IOLs) and review the surgical outcome.
Methods This retrospective, non-comparative, single surgeon, interventional, consecutive case series examined 10 patients (10 eyes) who underwent the surgical procedure from October 2011 to December 2012. Reliability, reproducibility, and intraoperative and postoperative complications of the technique were analysed.
Results The technique involved suction levitation of a 3-piece acrylic foldable IOL in six cases, 1-piece acrylic foldable IOL in three cases and a plate haptic IOL in one case. The IOL was exchanged in four eyes whereas the same IOL was repositioned in six eyes with sulcus repositioning in two eyes and glued intrascleral fixation in four eyes. Intraoperative suction loss and a subsequent IOL dislocation were reported in 1 (10%) eye. Early preoperative complications included pigment dispersion in 1 (10%) eye, grade 2 anterior chamber cellular reaction in 2 (20%) eyes and intraoperative corneal oedema in 1 (10%) eye which resolved with medical line of management. Intermediate and late complications included macular oedema in one patient (10%) which resolved considerably with medical line of management. No incidence of postoperative vitreous or retinal haemorrhage, retinal break or retinal detachment was reported.
Conclusions The early results demonstrate this surgical intervention as a reliable, reproducible and an effective alternative treatment option for levitation of dislocated IOLs with a low complication rate.
- Retina
- Treatment Surgery
- Vitreous
Statistics from Altmetric.com
Introduction
Despite the advancement and improved technicalities, reduced complication rate and hastened visual recovery period in phacoemulsification procedure, the risk for significant complications, such as nucleus or lenticular fragment drop into the vitreous and posterior dislocation of the intraocular lens (IOL) into the vitreous, still remains.1 ,2
Various methods have been described for the management of dislocated IOLs lying flat on the retina. Technical handling of a posteriorly dislocated IOL requires lot of surgical expertise to avoid the risk of retinal traction and creating an iatrogenic tear. The soft tipped-extrusion cannula first described by Flynn et al3 is commonly used during vitrectomy in complex retinal detachments for internal drainage of subretinal fluid.4 We describe the use of extrusion cannula without sleeves for facilitating levitation of dislocated IOL with suction through 23-gauge transconjunctival sutureless vitrectomy. A 23-gauge sleeveless-extrusion cannula helps to create suction on the optic of the IOL as it gives a larger surface area with respect to the soft-silicone tip to hold on to the IOL, thus facilitating the ability to lift and levitate the IOL into the pupillary plane.
Methods
In this retrospective non-comparative series of consecutive cases in which the technique to levitate dislocated IOL was performed, the personal log of a single surgeon (As A) from October 2011 to December 2012 was reviewed. The study protocol was approved by the Institutional Review Board and confirmed to the Declaration of Helsinki. A well-informed consent was taken from all the patients undergoing the procedure and patients with at least 9 months postoperative follow-up data were included from most end point analyses.
Preoperatively, all the patients had a complete ophthalmic examination, including best corrected visual acuity (BCVA), slit-lamp examination, intraocular pressure (IOP) and indirect ophthalmoscopy. A pre-existing or any coexisting ocular pathology was considered as a confounding factor as it could affect the final outcome and were excluded from the study. Three cases included in the study were those who had an intraoperative IOL dislocation during cataract surgery at our centre and seven cases reported an IOL dislocation at varied intervals within the first postoperative week wherein the IOL was completely dislocated into the vitreous cavity. Cases with intraoperative IOL dislocation were levitated in the same sitting and the remaining seven cases also underwent the levitation procedure as soon as diagnosed. All the cases underwent IOL levitation within the first postoperative week of IOL dislocation. Various intraoperative features like the type of IOL levitated, incidence of loss of vacuum and a subsequent drop while levitating an IOL and other intraoperative and postoperative complications were recorded.
Sulcus placement of an IOL was done in cases with adequate capsulorhexis support and glued intrascleral fixation was done in cases with inadequate capsulorhexis support. Patients undergoing IOL repositioning were exempted from IOL power calculations whereas patients undergoing IOL exchange were categorically taken up for IOL power calculation. Intraoperative data included surgical approach, management technique (reposition, IOL exchange or removal) and additional procedures performed concomitantly.
Examinations were performed 1, 3 and 7 days postoperatively, then every week for the first month and at monthly intervals for 9 months. Each examination included the BCVA, central macular thickness on optical coherence tomography, IOP, and anterior and posterior segment inflammation, fundus biomicroscopy, lens positioning and complications.
Surgical technique
All the surgeries were performed with constellation machine from Alcon and local anaesthesia was used comprising a peribulbar injection of a mixture of lidocaine 1%, bupivacaine 0.5% and hyaluronidase. Standard 23-gauge 3-port pars plana vitrectomy incisions were framed and the initial step was complete removal of the vitreous to prevent traction on the retina from subsequent manoeuvres. All the vitreo-lenticular adhesions were gently released from the retinal surface using the vitrectomy probe. A complete vitrectomy with careful separation and removal of the posterior hyaloid face was performed prior to lifting the IOL. Once the lens implant was freed from such attachments (figure 1A), it gently floated to the posterior pole of the eye. Care was taken to shave the vitreous as close to the surface of the peripheral retina and pars plana.
Levitation of dislocated posterior chamber intraocular lens (IOL). (A) Vitrectomy is done to clear all vitreo-lenticular adhesions. (B) Sleeveless-extrusion cannula is placed close to the anterior surface of the optic of the IOL; vacuum is initiated and occlusion is achieved. (C) IOL is lifted from the surface of retina. (D) The IOL is lifted, brought in to the mid-pupillary plane and is grasped by an end opening forceps.
The sleeveless-extrusion cannula was connected to the vitreotome aspiration and the vacuum was set to 300 mm Hg, with the cutting function turned off. Occluding the IOL before completing the vitrectomy was avoided to minimise the risk of peripheral retinal breaks due to trapping of the vitreous in the lumen of the cannula.
As the IOL rested flat on the retina, the sleeveless-extrusion cannula was placed in contact with the centre of the optic and suction was initiated to allow a firm grasp (figure 1B). Addressing the IOL with extrusion cannula without sleeves gives a larger surface area to be adhered to the IOL. The suction can be dynamically controlled with the foot pedal. The IOL was lifted from the surface of the retina (figure 1C) and was brought anteriorly, just behind the iris. The IOL was grasped by the end opening forceps introduced from the corneal incision under direct visualisation through the microscope; the suction was turned off and the extrusion cannula was then removed as the forceps grasped the IOL (figure 1D). The surgeon then proceeds to remove, reposition or exchange the IOL, depending on the status of the capsulorhexis rim and the type of IOL in each individual case (web only video file). The retinal periphery was checked 360° with scleral indentation to rule out any retinal breaks.
Results
Data were entered in a Microsoft Excel sheet (Microsoft Corp, Redmond, Washington, USA) and analysed using SPSS V.16.1 (SPSS Inc, Chicago, Illinois, USA). The change in the mean preoperative and postoperative visual acuity was analysed using the Wilcoxon signed-rank test. Differences were considered statistically significant at p value <0.05.
Of 15 identified cases, complete case notes were available for 10 eyes whose database was evaluated. The study included 10 eyes of 10 patients (seven men, three women; mean age of 57.1±4.58 years; range 51–63 years) with a mean follow-up of 36 weeks. The dislocation involved a 3-piece foldable IOL in six cases, 1-piece foldable IOL in three cases and a plate haptic IOL in one case. Intraoperatively, suction loss and a subsequent IOL dislocation while levitating the IOL from the surface of retina were seen in 1 (10%) eye and a second attempt was made to create an effective suction. No intraoperative or any postoperative complication was observed in this case in the entire follow-up. Intraoperative corneal oedema was seen in 1 (10%) eye which resolved in the immediate postoperative period. On the first postoperative day, pigment dispersion was observed in 1 (10%) eye and grade 2 anterior chamber cellular reaction was seen in two eyes which resolved with topical medication. Late postoperative complication included macular oedema in 1 (10%) eye which resolved considerably with medical line of management but eventually led to a compromised vision of 0.6 Snellen's decimal equivalent in that eye. The mean central macular thickness at 9 months was 181.9±9.39 µm. None of the eyes had postoperative vitreous or retinal haemorrhage, retinal break or retinal detachment (table 1).
Demographics of eyes with sleeveless-extrusion cannula-based suction levitation of dislocated posterior chamber IOL (vision in Snellen's decimal equivalent)
The mean BCVA was 0.96±0.1 (table 1). The mean postoperative IOP as measured with non-contact tonometer was 13.2±1.8 mm Hg and there was no statistically significant change in the IOP at 9 months follow-up (p=0.32).
In all, out of 10 eyes, eight eyes with inadequate sulcus support underwent glued intrascleral fixation of an IOL and two eyes underwent sulcus implantation of an IOL. Out of three eyes which had intraoperative dislocation, repositioning in the sulcus was done in one eye and the remaining two eyes underwent glued intrascleral fixation of an IOL. The IOL remained well positioned throughout the follow-up interval and no recurrence of IOL dislocation was reported. The final vision and symptoms were stable in nine eyes and improved considerably in one eye which developed macular oedema out of the total 10 patients. Repeat surgery was not required in any of the eyes.
Discussion
Since the inception of the first intraocular implant in 1949 by Dr Harold Ridley, IOL dislocation has been recognised as an important complication of cataract surgery. Perspex lens had to be abandoned as a 13% rate of IOL dislocation5 was reported. Improvements in IOL design have decreased the reported incidence of dislocation of rigid posterior chamber IOLs from 0.2% to 2%.6 ,7 Phacoemulsification with implantation of various foldable IOL designs has become the established cataract surgery technique8 and, consequently, the incidence of dislocation of foldable IOLs has increased.9
Inadequate capsular support is the most common cause of IOL dislocation and most commonly manifests in the early postoperative period,4 but late, ‘in-the-bag’ dislocation of IOLs owing to progressive zonular dehiscence has been increasingly reported. Dislocation of a posterior chamber IOL into the vitreous cavity is an uncommon but serious complication. Numerous techniques for the management of posteriorly dislocated IOLs have been described.6–14 Retinal forceps have been described to lift the IOL, although they run a risk of damaging the retina directly or indirectly;14 the IOL is often sneaky, slippery, difficult to grasp and manipulate. By lifting the IOL from the retinal surface with an illuminated pick or hook, the IOL optic can be grasped with serrated or diamond-dusted forceps.14 Olson et al13 devised a suction-based grasping tool that has a suction cup at its terminal end for lifting the dislocated IOLs. But it necessitates the use of specially designed suction tips to allow grasping and stabilisation of the IOL. The fragmatome tip has been described to manipulate the posteriorly dislocated IOLs by applying adequate suction to the centre of the anterior surface of the IOL optics.15
However, the device requires a conjunctival peritomy, which can cause conjunctival oedema, and also necessitates a 20-gauge sclerotomy wound. Moreover, its availability and accessibility may be an issue to many surgeons and it is also comparatively bulky to hold as compared with a 23-gauge extrusion cannula. Perflurocarbon liquids (PFCL) have also been used to prevent the adjacent retina from damage16 and to facilitate the anterior dislocation of luxated IOL. They have high density and low viscosity and it is these characteristics that allow easy aspiration and injection of PFCL in a 23-gauge vitrectomy system where it can be injected to levitate the IOL in the pupillary plane. However, ocular toxicity due to retained PFCL, including uncontrolled IOP,17 corneal epithelial toxicity18 and decreased focal sensitivity of the retina,19 has been reported. An in vitro study showed that PFCL is directly toxic to human retinal pigment epithelial cells when exposed to the cells for 7 days.20 Retinal forceps are often used to manipulate dropped IOLs and are usually the standard mainstay of treatment in vitreo-retinal surgery. Accidental pinching and creation of an iatrogenic retinal tear while lifting an IOL from the surface of the retina is always a possibility with its use. Often the IOLs are sneaky, slippery and difficult to grasp14 especially in cases of plate haptic IOLs.
Extrusion cannula is used primarily for internal drainage of subretinal fluid in eyes with rhegmatogenous retinal detachments. It is also used to remove haemorrhage, gas or silicone oil in the subretinal space along with removal of surface retinal haemorrhage. The flexible silicon sleeve fits snugly within the rigid outer shaft of the instrument to prevent an air or fluid leakage around the outside of the cannula and provides better access due to its flexibility into the subretinal space.21 Santos and Roig-Melo22 proposed lifting the IOL by the optic with a silicone-tip aspiration cannula connected to the vacuum of the vitrectome. Removal of the silicon sleeve gives a wider access of the bore of the cannula to create an effective suction around the IOL. The authors conceptualise that the vacuum created by the sleeveless-extrusion cannula is strong enough to hold the optic of an IOL in the vitreous cavity. Since a complete pars plana vitrectomy seems mandatory to avoid retinal traction with a high risk of retinal breaks, triamcinolone can be used to increase the visibility of the vitreous adhesions in the posterior chamber before any anterior IOL dislocation. Care is taken that the lumen of the cannula faces the flat surface of the optic of IOL and that it completely apposes and occludes the IOL optic, thereby, creating an effective active suction to grasp and lift the IOL. Meanwhile, no pressure is exerted on the IOL while trying to occlude and create suction and no passive suction flow to move the IOL is attempted either. This prevents any uncontrolled movement of the IOL that could be detrimental for the retina. The linear control of the foot pedal helps to increase the vacuum as and when needed during the levitation of IOL. Loss of vacuum while holding and lifting the IOL was reported in one case and a second attempt had to be made to lift the IOL. The loss of vacuum control was probably due to ineffective apposition of the lumen of the cannula to the surface of the IOL optic.
A dislocated IOL can cause complications such as decreased vision, monocular diplopia, glare, hyphaema, iritis, secondary glaucoma, corneal decompensation, cystoid macular oedema, and peripheral retinal traction and subsequent retinal detachment.23 The complications associated with dislocated IOLs like cystoid macular oedema, corneal oedema, glaucoma and intraocular inflammation are often difficult to differentiate from consequences of the initial complicated cataract surgery. In our limited series of cases, we did not come across any major complication, probably because the effective time interval between the original cataract surgery and the dislocated IOL levitation was minimal. This highlights that the levitation technique with sleeveless-extrusion cannula is an effective method although the final visual outcome can be affected by many variables in a complicated cataract surgery.
During surgical intervention, an important consideration is whether to remove, reposition or exchange the dislocated posterior chamber IOL after performing a pars plana vitrectomy. In eyes with inadequate capsular support, glue assisted intrascleral sutureless haptic fixation is a good surgical option.24 Following a posterior capsule rupture, 3-piece IOLs are the preferred choice for sulcus implantation.25 This is directly reflected in our study as six cases had a 3-piece dislocated posterior chamber IOLs. These IOLs were levitated and as glued intrascleral fixation also necessitates the use of 3-piece IOL, it was not removed and the glued procedure was performed in four cases with inadequate sulcus support. The dislocated plate-haptic IOL in one case and a 1-piece IOL in three cases were levitated and exchanged for a 3-piece acrylic hydrophobic foldable IOL and a glued procedure was performed.
The advantage with sleeveless-extrusion cannula-based suction levitation technique is that it is safe as it does not tend to damage the retina while trying to pick and levitate the IOL unlike a retinal forceps. Reliability and reproducibility are the two important parameters for any surgical technique to be effective. This technique was reproducible in all the cases and was reliable too with a favourable complication rate. Moreover, this technique was effective for dislocation of any type of IOL including the plate haptic IOLs which are often difficult to grasp with a retinal forceps, and no difficulty was encountered in the levitation process. Another advantage is that no additional device is required and inaccessibility or unavailability of the device will not be an issue.
In conclusion, in this retrospective analysis, it seems that short-term outcomes of suction-based levitation of posterior chamber dislocated IOLs in eyes are encouraging. The results presented here must be interpreted with caution for a number of reasons. First, this is a retrospective study with a relatively small number of subjects. Therefore, only large differences in visual acuity or in the number of complications might be recognised as significant by the statistical tests used, thereby making more subtle differences difficult to ascertain. Moreover, ethical implications would preclude a prospective study and also it is difficult to ascertain as to which patients will need this surgical procedure. Second, the mean follow-up period of 9 months is relatively short as compared with many of the previous reports on the management of dislocated IOLs. Despite the limitations of this study, it does provide information regarding the technique and postoperative outcome of levitation and subsequent IOL implantation in these eyes and indicates the need for further prospective trials with longer follow-up. Adequate follow-up and study sample size remain critical issues with any new approach in technique or technology.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Files in this Data Supplement:
- Data supplement 1 - Online video
Footnotes
-
Contributors All authors included on this paper fulfil the criteria of authorship. In addition, there is no one else who fulfils the criteria but has not been included as an author. Study plan, conception and design: PN, AmA and AsA. Data acquisition: DAK and AsA. Drafting article: PN and AmA. Final approval: AmA and PN.
-
Competing interests None.
-
Patient consent Obtained.
-
Ethics approval Local institutional review board.
-
Provenance and peer review Not commissioned; externally peer reviewed.