|Year : 2015 | Volume
| Issue : 4 | Page : 237-240
Nucleus drop during small incision cataract surgery: A report of four cases
Adekunle Rotimi-Samuel1, Adeola Olukorede Onakoya1, Olufisayo Temitayo Aribaba1, Kareem Olatubosun Musa1, A Sunday Alabi2, Folashade Bolanle Akinsola1
1 From the Department of Ophthalmology, Lagos University Teaching Hospital, Idi Araba, Lagos, Nigeria
2 From the Department of Ophthalmology, Mecure Eye Centre, Oshodi, Lagos, Nigeria
|Date of Web Publication||14-Jan-2016|
From the Department of Ophthalmology, Lagos University Teaching Hospital, Idi Araba, Lagos
Source of Support: None, Conflict of Interest: None
Small incision cataract surgery (SICS) offers the benefits of a phacoemulsification (phaco) surgery without the attendant high cost, but it is not without certain risk such as nucleus drop into the vitreous as seen in phaco. A retrospective study of SICS and associated factors leading to nucleus drop during surgery, challenges of management and the visual outcomes. Of 793 eye surgeries performed during the study 586 were SICSs. Nucleus drop during SICS occurred in 0.68% of patients. Can-opener technique of capsulotomy, use of dispersive viscoelastic, diabetes mellitus, lack of anterior vitrectomy machine and poor access to immediate posterior vitrectomy were important problems in the management of the cases of nucleus drop in this study. The visual outcomes were poor in all the cases of nucleus drop. Careful patient selection for SICS and the use of continuous curvilinear capsulorhexis are advocated. An interior vitrectomy machine should be available to all cataract surgeons. It is good professional practice to be acquainted with the available vitreo-retina surgeons for urgent assistance in cases of nucleus drop.
Keywords: Immediate vitrectomy, nucleus drop, small incision cataract surgery
|How to cite this article:|
Rotimi-Samuel A, Onakoya AO, Aribaba OT, Musa KO, Alabi A S, Akinsola FB. Nucleus drop during small incision cataract surgery: A report of four cases. Niger Postgrad Med J 2015;22:237-40
|How to cite this URL:|
Rotimi-Samuel A, Onakoya AO, Aribaba OT, Musa KO, Alabi A S, Akinsola FB. Nucleus drop during small incision cataract surgery: A report of four cases. Niger Postgrad Med J [serial online] 2015 [cited 2022 Aug 12];22:237-40. Available from: https://www.npmj.org/text.asp?2015/22/4/237/173977
| Introduction|| |
Cataract surgery remains a significantly cost-effective healthcare intervention.  Surgical methods have evolved most rapidly in the last 60 years with the successive introduction of the extra-capsular cataract extraction (ECCE), small incision cataract surgery (SICS) and phacoemulsification (phaco) methods. , SICS and phaco both permit cataract surgeries through smaller incisions than in ECCE, leading to shorter healing periods and less risk of astigmatism.  In this regard, phaco is superior to SICS, but the cost of equipment and the steep learning curves are important barriers to its widespread use in poor countries.
SICS is now frequently employed for cataract surgeries in Nigeria, but it is not without its peculiar risks such as inappropriate sclera flap thickness, inadequate wound size, zonular dehiscence and subsequent vitreous loss.  A more catastrophic complication of cataract surgery is dropped nucleus with the possibility of sight-threatening phacoanaphylactic endophthalmitis, glaucoma, retinal breaks and detachment. , An early vitrectomy (under a 'no-move and no-wait policy) has been shown to result in a more favourable visual outcome. 
The case files of all adult patients who underwent only SICS between June 2010 and June 2013 were reviewed. Of a total of 793 eye surgeries, 586 were SICS cases out of which four had nucleus drop.
| Case Reports|| |
The first patient was N.C, a 78-year-old male with age-related cataract who was diabetic and hypertensive for 15 years. The blood pressure was 120/70 mmHg. The best-corrected visual acuity (BCVA) was 6/18 in the right eye and 6/60 in the left eye. Intra-ocular pressures (IOPs) were 17 mmHg and 18 mmHg in the right and left eye, respectively. Fasting blood sugar (FBS) was 91 mg/dl and haemoglobin A1c (HbA1c) was 6.1%. The anterior segment of each eye was otherwise normal. SICS was performed in the left eye during which procedure the can-opener method of capsulotomy was employed; no hydro-dissection or hydro-delineation was performed before dialling the nucleus into the anterior chamber during which the nucleus dropped into the vitreous. Sponge and scissors vitrectomy were done, and the wound sutured. He was placed on dexamethasone and tropicamide eye drops; oral analgesics and acetazolamide tablets. He had visual acuity of hand motion and striate keratopathy the first post-operative day. He could not access a vitreo-retina (V-R) surgeon and intra-ocular inflammation subsided only after about 8 months at which time the crystalline lens seemed attached to the inferior retina. The patient was then lost to follow-up for another 6 months when he presented with pain, redness and watering in the same eye. Visual acuity in the eye was hand motion, with hyperaemic conjunctiva and a hard eye (it was difficult to measure IOP on account of severe pain). The lens was displaced into the anterior chamber. Urgent vectis extraction of the lens was performed, but the patient developed post-operative endophthalmitis which settled with intra-vitreal cefuroxime injections. The final visual acuity in the left eye was hand motion.
The second patient was E.N., a 68-year-old male who was diabetic for 17 years and hypertensive for 12 years. The blood pressure before surgery was 130/80 and HbA1c 7.8%. Visual acuity was 1m counting fingers in the right eye and hand motion in the left eye. IOP in the right eye was 17 mmHg and 18 mmHg in the left. The pupils were both round and reactive. Light projection test was accurate in each eye, and the corneas were clear. Capsulotomy during SICS was by the can-opener technique, but neither hydro-dissection nor hydro-delineation was done. Dialling the nucleus into the anterior chamber resulted in it dropping into the vitreous. A sponge and scissors vitrectomy was performed, the wound sutured and the patient placed on anti-biotics, anti-inflammatory eye drops and pressure lowering drugs. He was referred to a V-R surgeon on the 1 st day after surgery and had vitrectomy 2 days after the cataract surgery. The procedure was completed with a prophylactic endo-laser treatment of the retina. An anterior chamber intra-ocular lens was inserted, and the BCVA 3 months post-operatively was 3 m counting fingers.
The third patient was a 74-year-old female with bilateral age-related cataract who is a known hypertensive on medications. She was not a known diabetic, and the FBS was 74 mg/dl. Her blood pressure before surgery was 120/70 mmHg. The BCVA was 2 m counting fingers and ½ m counting fingers in the right and left eyes, respectively. The IOP in the right eye was 17 mmHg and 20 mmHg in the left. There were nuclear sclerosis and posterior sub-capsular cataract in the two eyes. The posterior segment of each eye was normal except choroidal sclerosis and loss of fovea reflex. During the SICS for the right eye, anterior capsulotomy was by can-opener technique. There was posterior capsular rent, and zonular dialyses were immediately followed by a drop of the whole nucleus into the vitreous cavity. A sponge and scissors vitrectomy was performed and patient placed on steroids, anti-biotics and pressure lowering drugs. He was referred to a V-R surgeon who performed a vitrectomy 4 days after initial surgery. An anterior chamber intraocular lens was placed in situ. Post-operatively, the patient developed bullous keratopathy and the BCVA in the eye was 2 m counting fingers 13 months after the SICS.
The fourth patient was T.U., a 78-year-old hypertensive female with bilateral age-related cataract. The BCVA was 6/60 in the right eye and 6/24 in the left eye. The IOP was 10 mmHg and 11 mmHg in the right and left eye, respectively. The morphology of the cataract included posterior sub-capsular cataract, nuclear sclerosis and cortical spokes. A significant posterior synechiae was detected only intra-operatively. Can-opener technique of capsulotomy was employed. The nucleus was prolapsed into the anterior chamber and fractured. The first half was successfully delivered, but the second half dropped into the vitreous. There was no vitreous loss, and the wound was closed. The zonules were thought to be weak not only from old age but also from previous ocular inflammation as evidenced by the posterior synechiae. Perhaps more significant was the fact that topical anaesthesia was employed in the fourth case. It proved inadequate and patient became restless.
The patient was placed on anti-biotic and steroid drops and the pupil actively dilated. The visual acuity on the 1 st -day post-operatively was 1 m counting finger. She had vitrectomy 4 days after the SICS.
In all four cases, there was no recorded pre-operative evidence of previous intra-ocular inflammation, zonular dehiscence or lens subluxation. Only dispersive viscoelastic was employed for anterior chamber manipulations and surgeries were performed by three different advanced trainee ophthalmologists and an experienced consultant ophthalmologist who were all conversant with SICS. [Table 1] shows the visual acuity pre- and post-operatively for patients with nucleus drop.
| Discussion|| |
The can-opener technique of capsulotomy employed in all four cases is less resilient than continuous curvilinear capsulorhexis and may lead to capsule rupture and vitreous loss.  On the other hand, a continuous curvilinear capsulorhexis has strength and stability, making it less likely for capsular rent that may lead to nucleus drop. 
Dispersive viscoelastics tend to exit the anterior chamber more readily than cohesive types during intra-operative manoeuvres such as capsulotomy and capsulorhexis when the surgical wound may slightly open. This may leave the anterior chamber poorly pressurised and cause a run-away anterior capsular tear and nucleus drop. 
All the patients had their hypertension well-controlled before surgery. Although no literature was found linking hypertension with nucleus drop, uncontrolled systemic hypertension has been linked to elevated IOP in a population-based study.  The patients had no intra-operative vital signs monitoring, and this made it impossible to rule out the temporary anxiety-related intra-operative elevation of blood pressure. Vital signs monitoring might have indicated a need for top-up anaesthesia for the fourth patient much earlier than the onset of his pain-related restlessness.
All the four patients in this study had age-related cataracts which are also associated with weakened zonules. These may have been weakened further in the two cases with long-term diabetes mellitus. It is advisable to have pupils widely dilated pre-operatively using a tropicamide/phenylephrine combination and a meticulous search for signs of localised zonular weakness or frank dehiscence. The sole dilating agent used in the clinic for all the four patients was tropicamide and may have precluded a detailed anterior segment assessment prior to cataract surgery. A widely dilated pupil intra-operatively is also essential for early recognition of and proper surgical management of posterior capsule rupture before the nucleus drops.
A hydro-dissection frees the crystalline lens from the capsule, while a hydro-delineation creates a cushion of fluid between the nucleus and the epinucleus. Both manoeuvres allow an easier prolapsed of the nucleus into the anterior chamber with less stress on the zonules and the lens capsule. Neither of these manoeuvres was performed in any of the cases.
A sponge and forceps vitrectomy was performed for each patient on the table except the fourth patient where there was no demonstrable vitreous loss. This is not the most effective way of removing vitreous and may have contributed to one patient eventually developing endophthalmitis. A machine anterior vitrectomy would have cleared the vitreous more thoroughly in all cases and might have led to better outcomes.
The third patient developed bullous keratopathy which might have been due to the presence of vitreous in the anterior chamber following the initial surgery. However, the insertion of anterior chamber intra-ocular lens should have been postponed to allow inflammation to settle and the cornea to heal. The patient probably lost too much of the corneal endothelial cells from vitreous touch.
The crystalline lens excites inflammatory reaction in the vitreous quickly, and a dropped nucleus requires an urgent posterior vitrectomy. The best visual outcome can be obtained when the vitrectomy is performed as an extension of the original cataract surgery (no-wait and no-move policy). The poor visual outcome in this case series delayed posterior vitrectomy. This allows for intense ocular inflammation and possible infection which may compromise vision. Furthermore, prolonged contact of vitreous with corneal endothelium compromises its function leading to cloudiness and subsequent bullous keratopathy as seen in one of the cases. None of the patients described had vitrectomy as an extension of the original cataract surgery, and this may further explain the poor visual outcome in all the patients. Posterior vitrectomy should, therefore, be performed as soon as possible in cases of dropped nucleus before a cloudy cornea rules out an urgent intervention.
The question may be asked: Who should pick up the bill for posterior vitrectomy in cases of dropped nucleus, especially when the patient is paying out of pocket, and a V-R surgeon/equipment are not on site? It might be a good professional practice to be acquainted with the nearest V-R surgeon. The V-R surgeon (in private practice) who performed the surgery for the second and third patients did them free of charge.
| Conclusion|| |
SICS offers the advantage of a shorter recovery time for the patient without the associated cost of paying for a phaco procedure. However, the potential complications should be anticipated. Patients should be carefully selected for SICS, adequate care being taken to identify any zonular dehiscence pre-operatively. Adequate anaesthesia and a widely dilated pupil are essential during surgery. Continuous curvilinear capsulorhexis and hydro-dissection are recommended. An urgent vitrectomy should be performed as an extension of the original cataract surgery. At the very least, an anterior vitrectomy machine should be available to cataract surgeons for immediate use. It is probably not a good option to insert an anterior chamber intraocular lens in cases of lens drop where posterior vitrectomy was not performed as an extension of the original cataract surgery. The vitrectomies performed free of charge for the second and third patients demonstrates the benefit of cordial professional relationship among ophthalmologists.
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Conflicts of interest
There are no conflicts of interest.
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