|Year : 2018 | Volume
| Issue : 1 | Page : 38-42
Same-setting pars plana vitrectomy for management of dislocated lens fragments during phacoemulsification
Asaad N Ahmed, Hassan S Yousef, Hamdy O Abdelrahaman
Department of Ophthalmology, Faculty of Medicine, Al-Azhar University, Asyuit, Egypt
|Date of Submission||11-Apr-2018|
|Date of Acceptance||19-Jun-2018|
|Date of Web Publication||20-Nov-2018|
Hassan S Yousef
Department of Ophthalmology, Faculty of Medicine, Al-Azhar University, Asyuit Branch, Asyuit, PO Box 71524
Source of Support: None, Conflict of Interest: None
Context Dropped lens fragments in the vitreous cavity after phacoemulsification can cause potentially serious complications.
Aim This prospective noncomparative study aimed to evaluate the effect of same-setting pars plana vitrectomy (PPV) for posteriorly dislocated lens fragments during phacoemulsification.
Patients and methods A prospective study was conducted on all consecutive cases (seven patients) with PPV performed for retained lens fragment from January 2016 to December 2017.
Statistical analysis Descriptive statistics were calculated using SPSS software (version 13.5). Values are expressed as mean±SD, and statistical significance was determined using the Student’s t test for paired data.
Results The patients underwent PPV, at the same setting, implanting hard polymethyl methacrylate (PMMA) on the ciliary sulcus in five cases, three-piece acrylic foldable intraocular lens (IOL) in two cases and iris fixating verisyse behind the pupil in one case. The mean±SD improvement of visual acuity is 0.17±0.18, 0.20±0.16, 0.35±0.26, and 0.40±0.18 at first week, first, third, and sixth month, respectively.
Conclusion The same-setting PPV for the dislocated lens fragment is of good visual prognosis and takes the advantage of surgery with a clear cornea and minimally inflamed eye that enable better removal of retained lens fragments with fewer complications.
Keywords: nucleus loss, pars plana vitrectomy, phacoemulsification, retained lens fragment
|How to cite this article:|
Ahmed AN, Yousef HS, Abdelrahaman HO. Same-setting pars plana vitrectomy for management of dislocated lens fragments during phacoemulsification. Al-Azhar Assiut Med J 2018;16:38-42
|How to cite this URL:|
Ahmed AN, Yousef HS, Abdelrahaman HO. Same-setting pars plana vitrectomy for management of dislocated lens fragments during phacoemulsification. Al-Azhar Assiut Med J [serial online] 2018 [cited 2019 Aug 20];16:38-42. Available from: http://www.azmj.eg.net/text.asp?2018/16/1/38/244144
| Introduction|| |
As a result of the use of phacoemulsification procedure in cataract surgery, visual outcome and patients’ convalescence have been significantly ameliorated when compared with extracapsular cataract extraction . In accordance with the advancement in the instruments and technologies in phacoemulsification process, surgeons have to follow a learning curve for optimal achievement of this technique. Accordingly, there are some unique complications to phacoemulsification process. Dropped nucleus, nuclear parts, and the all nucleus dislocation into the vitreous cavity are the most serious complications that can happen at any stage of the phacoemulsification operation even if carried out by skilled surgeons .
Pars plana vitrectomy (PPV) has been used successfully to retrieve the retained lens fragments to minimize the risk of further complications ,, although most authors proclaimed that the optimal timing of PPV is controversial , as the histological studies showed that inflammatory reaction caused by the retained lens fragment may be relieved spontaneously or with medications and it may worsen with longer duration of lens fragments remaining within the eye ,. Some vitreoretinal surgeons propose performing a same-setting PPV, as they consider it the optimal time to remove retained lens fragments. Some other surgeons consider that the standard parslana vitrectony (SD-PPV) is unnecessary, complicates the informed consent process, and may increase the risk of complications ,,.
The aim of our study is to ensure that same-setting PPV is optimal in removal of the dislocated lens fragments before any further time-dependable complications of the primary cataract surgery that related to presence of the fragments in the vitreous cavity and to avoid unnecessary two surgical settings.
| Patients and methods|| |
This was a prospective study including eight eyes that presented with nucleus or lens matter loss into the vitreous during complicated cataract surgery (phacoemulsification). The surgical procedure was done from January 2016 to December 2017 in Al Safwa Eye Center, Sohag. The present study was performed in accordance with the National Institutes of Health guidelines. An informed written consent was obtained from each participant.
Follow-up data were taken at the second day of surgery, 1 week and at 1, 3, and 6 month after vitrectomy for inclusion in the study. The exclusion criteria included those who underwent previous PPV, those with macular lesions such as myopic changes or age-related macular degeneration, patients with ocular pathology, diffuse macular edema (DME), hypertensive maculopathy, optic atrophy, or glaucoma.
The parameters of the study included demographics, pre-existing eye diseases, details of the cataract surgery, the approximate size of nuclear fragments in the vitreous, use of phacofragmentation (fragmatome) and/or heavy liquids, operative complications such as retinal tear or retinal detachment, final postoperative best-corrected visual acuity (BCVA), IOP, and complications, which were recorded during the follow-up. A standard three-port PPV is the procedure of choice after stability of the cataract wound was ensured using 23-G system using a three-port transconjunctival microcannula-based 23-G PPV system. Microcannulas were inserted transconjunctivally, with the help of an insertion trocar, 3.5 mm posterior to the limbus in the inferotemporal, superotemporal, and superonasal quadrants. A 23-G vitreoretinal blade was inserted tangentially (∼30° parallel to the limbus).
The infusion cannula was placed in the inferotemporal quadrant, and plugs were used to temporarily close the other entry sites. Any residual lens materials surrounding the iris area were removed; care is taken to avoid breaking the capsule so that it remains ready for the final intraocular lens implantation. A core vitrectomy was performed, followed by the removal of the softer cortical lens material and vitreous around the nucleus.
A high-speed vitrectomy probe with a cutting rate of 1500–2500 cuts/min and a vacuum level of 300–500 mmHg was used during PPV. The balanced salt solution bottle height was set at 50 cm. A bimanual technique was used to push the nucleus into the port of the vitrectomy cutter with the endoilluminator probe.
In cases where hard lens materials were unable to be removed with the vitrectomy probe, a sclerotomy site was enlarged to accommodate a 20-G micro vitreoretinal blade and the fragmatome handpiece. Through this sclerotomy, intravitreal phacoemulsification with a 20-G titanium fragmatome was performed to remove the hard nucleus fragments in the mid-vitreous with a vacuum level of 100–150 mmHg.
A small volume of perfluorodecalin might be injected over the optic nerve to protect the macular area against the ultrasonic energy and mechanical trauma from the lens fragments especially in hard cases. The phacofragmatome tip if needed may be used to aspirate the nucleus material, assisted by the tip of the endoilluminator to keep the nuclear fragments near the phacofragmatome. After the vitrectomy and lensectomy were completed, a peripheral examination with scleral depression is performed, and peripheral vitrectomy was done to eliminate any peripheral vitreous traction. If there is any break or tear, an endolaser treatment was done.
At the end of the surgery, a placement of the intraocular lens (IOL) was performed in aphakic cases. If a small intact capsulorhexis was present, the IOL can be inserted in the sulcus, and if posterior chamber intraocular lens (PC-IOL) was impossible, anterior chamber intraocular lens (AC-IOL) could be placed. After the PPV, there was a follow-up control of the patients after 1 week, 1, 3, and 6 months. The corrected visual acuity was measured at each visit and included in the statistical analysis.
Descriptive statistics were calculated using SPSS computer program version 13.5 (IBM Corporation, New York, USA). Values are expressed as mean±SD, and statistical significance was determined using the Student’s t test for paired data. The McNemar test was used for evaluating the qualitative data such as presence of the cystoid macular edema (CME), corneal edema, retinal detachment, and high IOP.
| Results|| |
Eight patients were included in this study and underwent same-setting PPV, implanting hard polymethyl methacrylate (PMMA) on the ciliary sulcus in five cases, three-piece acrylic foldable IOL in two cases and iris fixating verisyse behind the pupil in one case. Overall, four (50%) of them were males, whereas four (50%) were females. Their ages varied from 55 to 66 years (mean±SD, 58.9±12.44) with precataract surgery BCVA (0.09±0.05) complicated by posterior dislocation of lens matter. They underwent 23-G vitrectomy using a three-port transconjunctival microcannula-based 23-G PPV system. We had to enlarge the port in two (25%) cases for fragmatome use, using perfluorocarbon (PFC) for macular protection in four (50%) cases.
The mean improvement of visual acuity ([Figure 1]) is 0.17±0.18, 0.20±0.16, 0.35±0.26, and 0.40±0.18 at first week, first, third, and sixth month, respectively; 75% of them had a final visual acuity of 0.3 or better, and 50% of them achieved a final visual acuity of 0.5 or better.
The mean IOP ([Figure 2]) at the first month was 15.6±2.5 mmHg, at third month was 16±3.25, and at the sixth month was 16.99±3.60.
With respect to the capsule rupture that led to nucleus drop, two cases with dense cataract, large nucleus, and small capsulorhexis were complicated by capsular blockage syndrome that resulted in large capsular tear and dropped nucleus. In the other six cases that experienced posterior subcapsular cataract with nuclear grade II, two cases showed rupture after phacoemulsification of the first piece. In addition, three cases showed rupture during phacoemulsification of the last piece. The last case showed pseudoexfoliation with partial zonular dialysis without the use of the capsular tension ring rupture, which occurred after phacoemulsification of the second piece.
| Discussion|| |
Although PPV is considered the superior surgical process for managing posteriorly dislocated lens fragments following cataract surgery, some researchers revealed that the patients did not undergo PPV after nuclear dropping. The patient’s visual acuity deteriorated to counting finger or worse owing to chronic complications such as corneal decompensation, glaucoma, retinal detachment (RD), and optic atrophy. There is no consensus regarding the timing effect of this procedure on the final visual outcome . Vitrectomy when achieved at the same setting carries the advantages of reduced patient stress levels, decreased operative time, avoidance of risks of repeated anesthesia, and minimize collateral damage to intraocular structures owing to fewer interventions by cataract surgeon in trying to extract dislocated lens fragments.
Its disadvantages comprise the risk of hypotony, suprachoroidal hemorrhage, and patient fatigue as a result of prolonged operative time ,. In the current study, the patients who underwent same-setting PPV had a mean BCVA of 0.17±0.18, 0.20±0.16, 0.35±0.26, and 0.40±0.18 at first week, first, third, and sixth months, respectively; 75% of them had a final visual acuity of 0.3 or better, and 50% of them achieved a final visual acuity of 0.5 or better.
Many other studies concluded that the timing of vitrectomy did not influence the visual outcome in respective large series of more than 100 eyes ,,. Kim et al.  reported that 75% of eight eyes operated on the same day as the cataract surgery had final vision of 0.66 or better with a mean of 0.62, whereas only 63% of the other 54 eyes operated later had final vision of 0.5 or better. Terasaki et al.  reported that 75% of four eyes operated on the same day as the cataract surgery had final vision of 0.7 or better with a mean of 0.68 compared with 70% of the other 10 eyes operated 2–7 days after cataract surgery.
Kageyama et al.  reported that 17 cases of PPV performed for dislocated lens fragment at the time of phacoemulsification had a mean best correct visual acuity (BCA) of 0.45 at the end of the study, in which 82% of the patients had a final visual acuity of 0.5 or better. In contrast, several other studies reported that PPV performed within a week after cataract surgery produced inferior outcomes compared with after a week, and recommended that PPV could be delayed until the eye has recovered from cataract surgery ,,,.
Other large series have failed to demonstrate a statistically significant meeting between the timing of vitrectomy and the final visual outcome ,,. Tommila and Immonen  reported that of eyes subjected to vitrectomy immediately after cataract extraction, 57% of the seven eyes achieved a vision of 0.5 or better with a mean 0.43 compared with 78% of 16 eyes that were vitrectomized 1–7 days after cataract surgery. Vanner and Stewart  found that early PPV was associated with better VA and fewer cases of previtrectomy and postvitrectomy retinal detachment, increased IOP, and intraocular inflammation/infection compared with later PPV.
This study confirmed good visual outcomes of the same-day PPV by removal the lens fragments before the onset of time-dependent inflammation and the accompanying complications. The advantages also comprise a clear cornea and mildly inflamed eye that help better removal of dropped lens pieces with less complications during the same phacoemulsification and PPV operation. So, further prospective consecutive conclusive clinical trials enrolling a large number of cases are recommended to compare early and delayed PPV in management of dislocated lens fragment during phacoemulsification with a longer follow-up period to test a superiority hypothesis comparing both groups and to provide insight on the proper timing of vitrectomy.
| Conclusion|| |
The visual outcomes of the same-setting PPV group in our study are good compared with many other studies taking advantage of a clear cornea and minimally inflamed eye to enable better removal of retained lens fragments, with fewer complications.
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Conflicts of interest
There are no conflicts of interest.
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