When all computers shut down: the clinical impact of a major cyber-attack on a general hospital

Importance

Healthcare organizations operate in a data-rich environment and depend on digital computerized systems; thus, they may be exposed to cyber threats. Indeed, one of the most vulnerable sectors to hacks and malware is healthcare. However, the impact of cyberattacks on healthcare organizations remains under-investigated.

Objective

This study aims to describe a major attack on an entire medical center that resulted in a complete shutdown of all computer systems and to identify the critical actions required to resume regular operations.

Setting

This study was conducted on a public, general, and acute care referral university teaching hospital.

Methods

We report the different recovery measures on various hospital clinical activities and their impact on clinical work.

Results

The system malfunction of hospital computers did not reduce the number of heart catheterizations, births, or outpatient clinic visits. However, a sharp drop in surgical activities, emergency room visits, and total hospital occupancy was observed immediately and during the first postattack week. A gradual increase in all clinical activities was detected starting in the second week after the attack, with a significant increase of 30% associated with the restoration of the electronic medical records (EMR) and laboratory module and a 50% increase associated with the return of the imaging module archiving. One limitation of the present study is that, due to its retrospective design, there were no data regarding the number of elective internal care hospitalizations that were considered crucial.

Conclusions and relevance

The risk of ransomware cyberattacks is growing. Healthcare systems at all levels of the hospital should be aware of this threat and implement protocols should this catastrophic event occur. Careful evaluation of steady computer system recovery weekly enables vital hospital function, even under a major cyberattack. The restoration of EMR, laboratory systems, and imaging archiving modules was found to be the most significant factor that allowed the return to normal clinical hospital work.

Vitreous traction and epiretinal membranes in diabetic macular oedema using spectral-domain optical coherence tomography

PURPOSE

The purpose of this study was to present an association between diabetic macular oedema (DME) and vitreoretinal interface abnormalities using 3D spectral domain optical coherence tomography (SD-OCT).

METHODS

In a retrospective study, charts and SD-OCT of consecutive patients with diffuse or focal DME were reviewed. Only one randomly chosen eye per patient with DME was included, and eyes that had another retinopathy that could affect the study analysis or that underwent vitreoretinal surgery were excluded.

RESULTS

Out of 58 eyes (58 patients) with DME, 11 eyes (19.0%) had vitreofoveal traction (Group A), either unifocally (n=6) or multifocally; that is, associated with additional extrafoveal traction site(s). Group B comprised 20 eyes (34.5%) that had sole extrafoveal vitreous traction, at either retinal and/or papillary sites. In each, the retinal oedema underlying extrafoveal traction was in continuum in at least one site with that at the central macula, as verified by the macular maps, thus presented as diffuse macular oedema. In Group C, 13 eyes (22.4%) had an epiretinal membrane (ERM), 1.5 × 3 mm to ≥6 × 6 mm in size that overlaid diffuse oedematous macula. Group D included 14 eyes (24.1%) that had neither vitreous traction nor ERM; 12 (20.7%) of them had DME secondary to leaking microaneurysms with or without leaking capillary beds, and the remaining two had leakage from non-microaneurysms sources.

CONCLUSIONS

DME was detected by the SD-OCT to be associated with sole extrafoveal vitreous traction in one-third of the patients. Further studies are required to evaluate the clinical consequences of these observations.

Protection of the conjunctival flap from contact with mitomycin C during tunnel-trabeculectomy

AIM

The mid-term appearance of the filtering bleb and surgical outcome following tunnel-trabeculectomy, in which protective measures were carried out to avoid contact between the mitomycin C (MMC) and the conjunctival flap, are presented.

METHODS

In a retrospective study the records of 20 consecutive patients who had undergone tunnel-trabeculectomy >/=24 months earlier, using fornix-based conjunctival flap and MMC (0.4 mg/ml) application were evaluated. Inclusion criteria were patients in whom: (I) the MMC-socked sponge was applied without contact with the conjunctival flap; (II) during MMC washout, a second Weck cell sponge was held anterior to the conjunctival flap, to protect the flap from mitomycin contact during its back-flow. Excluded were five patients who either did not complete 24 months of follow-up (n=4) or underwent an intraocular surgery during that period (n=1).

RESULTS

After 24-32 (26.9+/-2.2) months, the filtering bleb was completely vascularized and thick in 13/15 patients (86.7%), mostly vascularized with some para-limbal thick cysts in one and avascular and cystic in another. Mean intraocular pressure (IOP) dropped from a preoperative level of 25.3+/-7.0 mmHg with 3.5+/-0.9 hypotensive medications to 13.9+/-2.9 mmHg with 0.9+/-1.1 medications (P<0.0001, Wilcoxon test). Of the five excluded patients, the IOP ranged between 10 and 16 mmHg with 0-1 medications at the last examination, 1-15 months postoperatively.

CONCLUSION

In this pilot study, an intraoperative protection of the conjunctival flap from mitomycin contact was mostly associated with a vascularized and thick filtering bleb after mid-term follow-up. Further controlled prospective studies are required to confirm these observations.

Diabetic vitreopapillary traction and macular oedema

PURPOSE

To describe an association between optic disc traction and diabetic macular oedema (DME) unresponsive to laser treatment.

METHODS

A retrospective review of all patients with DME who attended our clinic between September 2001 and November 2003 was undertaken. The patients had undergone ophthalmic history and examination, fluorescein angiography, and optical coherence tomography (OCT) of the macular area and optic nerve head (ONH). A total of 10 nonvitrectomized eyes that were found to have an elevation of the ONH secondary to vitreopapillary traction were included in the analysis. Eyes with additional traction at the posterior pole were excluded.

RESULTS

Out of the 10 eyes (seven patients, aged 47-79 years) with vitreo-papillary traction, nine had previously undergone argon laser photocoagulation(s) for DME. In seven eyes (seven patients), OCT verified the vitreopapillary traction as the sole traction, whereas in the fellow eyes of three patients vitreomacular traction was evident as well. In the seven eyes with only vitreopapillary traction, OCT demonstrated parapapillary serous retinal detachment in two eyes and a diffuse DME in all eyes (mean foveal thickness, 396+/-144 microm). Maximal thickness of the papillo-macular bundle site was adjoining the elevated ONH in three eyes, and was maximal at the central macula in the other four eyes. Ultrasonography (n=5) revealed an incomplete detachment of the posterior hyaloid in each, adherent only at the ONH.

CONCLUSIONS

Diffuse DME unresponsive to laser treatment may be associated with vitreopapillary traction. Further studies should indicate whether these two phenomena could suggest a cause and effect in such eyes.

Spontaneous expulsive suprachoroidal hemorrhage

PURPOSE

To present a 90-year-old patient with spontaneous expulsive suprachoroidal hemorrhage (SESCH). This unique case suggests a mechanism of SESCH, which is still under debate.

METHODS

The patient, who had corneal inflammatory disease and diabetes mellitus, atherosclerosis, and glaucoma, presented with active ocular bleeding and expulsion of intraocular tissues. Almost the entire cornea was absent, except for several small and irregular areas in its periphery. Histopathologic evaluation of the eviscerated contents was performed.

RESULTS

Clinicopathologic evaluation revealed acute inflammation of the corneal remains as well as intraocular inflammation. Inflammatory necrosis of choroidal vessels was evident.

CONCLUSION

The findings point to the assumption that choroidal bleeding, secondary to vascular inflammatory necrosis, was the initial event in this case of spontaneous expulsive suprachoroidal hemorrhage. Presumedly, the intraocular pressure level was very high owing to continuous bleeding, which could result in a very large, rather than localized, tearing of the peripherally inflamed cornea.

Mini-trabeculectomy as initial surgery for medically uncontrolled glaucoma

PURPOSE

To report on the surgical outcome after at least 12 months of follow-up of mini-trabeculectomy (without radial incisions) as an initial surgery.

METHODS

In a prospective, institutional study, mini-trabeculectomy was performed as the initial surgical therapy on 41 eyes with medically uncontrolled glaucoma of 41 consecutive patients aged 40 years or older. Mini-trabeculectomy consists of a 3-mm fornix-based conjunctival flap, sclerostomy at 1 mm from the limbus, and a sclerocorneal tunnel without radial incisions. Of the 41 eyes, four eyes did not complete 12 months of follow-up. Of the remaining 37 eyes, one eye underwent cataract extraction 5 months postoperatively and was evaluated only for surgical complications. Thirty-six patients with a mean age of 70.3 +/- 7.4 standard deviation years (range, 54 to 87) completed 12 months or more of follow-up.

RESULTS

In the 36 eyes, mean preoperative intraocular pressure was 30.2 +/- 9.3 mm Hg (range, 19 to 54) with 3.0 +/- 1.2 hypotensive medications (range, 1 to 4). After postoperative mean follow-up of 25.0 +/- 9.2 months (range, 12 to 43), intraocular pressure was at or below the planned target intraocular pressure in 35 eyes (97.2%; P <.0001) and mean intraocular pressure was 16.0 +/- 2.8 mm Hg (range, 11 to 21) with 0.8 +/- 1.0 medications (range, 0 to 3). Postoperative complications in the 37 eyes included early postoperative aqueous leakage with moderately shallow or deep anterior chamber in two eyes (5.4%) and rapid cataract progression in one eye (2.7%). The four eyes that were excluded from the study had intraocular pressures of 10 to 16 mm Hg with 0 to 1 hypotensive medications, 3 to 9 months after surgery, respectively.

CONCLUSIONS

Mini-trabeculectomy, which may offer clinical and technical advantages over the standard trabeculectomy, was generally efficacious and relatively safe, based on outcome observed at a mean of 25 months follow-up. A controlled study is required to confirm these observations.

Halting pterygium recurrence by postoperative 5-fluorouracil

PURPOSE

To investigate the efficacy of postoperative 5-fluorouracil (5-FU) in halting recurrence of pterygium.

METHODS

Early recurrence of pterygium was detected in six eyes of six patients aged 40 to 66 years that, over a 3-year period, had undergone pterygium excision in our institution, using the "bare sclera" technique. Each of the hyperemic fibrovascular tissues was found to override the cornea by 1.5 mm or less in length. Five of these eyes had undergone a primary excision and one, a second operation (with intraoperative mitomycin C). Upon diagnosis, each eye was treated with two to four injections of 5-FU, administered into the dome of the fibrovascular tissue. The dose of 5-FU per injection was 1 to 3 mg (mean, 2.1 +/- 0.8 mg). Of all 126 eyes that underwent pterygium surgery during that 3-year period, pterygium recurred in nine additional eyes but was found to be 2 mm or more in length in each. These eyes were not treated by 5-FU.

RESULTS

In five of the six treated eyes, the pterygium became clinically atrophic and the recurrence process was stopped. No renewal of the recurrence process was detected after 12 months or more of follow-up. No major complications were related to the use of 5-FU.

CONCLUSION

This pilot study suggests that when early recurrence of pterygium is already evident, 5-FU treatment into the dome of the fibrovascular tissue may be beneficial in halting its progression, by rendering it atrophic. A prospective, randomized, controlled study is required to confirm the efficacy of this approach.

Hollow bandage contact lens

OBJECTIVE

To report on the use of a new bandage contact lens (BCL) for a leaking filtering bleb.

PATIENTS AND METHODS

A hollow BCL, with an internal central opening of 6 mm, has been applied on three eyes that had leaking blebs shortly after either trabeculectomy or combined cataract extraction and trabeculectomy, each with a fornix-based conjunctival flap.

RESULTS

The treatment with this lens was found beneficial: the leakage subsided and the patients were comfortable with the lens. The internal hollow of the BCL enabled us to monitor the intraocular pressure throughout the entire follow-up period without transient and repeated removal of the BCL.

CONCLUSION

The new hollow BCL was found efficacious. The study suggests that this lens may have advantages over the commonly used BCLs that are related to the elimination of the need for its frequent removal and reinsertion for tonometry. This decreases the risk of both the exposure of the lens and the filtering bleb to contamination and the interference with the continuity of the process of conjunctival epithelial closure.

Quantitative analysis of hydroxyl radicals in the anterior optic nerve of the cat following transient ischemia

PURPOSE

Ischemic insults in the optic nerve are relatively common ocular disorders. This study provides quantitative data on the generation of hydroxyl radicals in the anterior optic nerve of the cat during the early reperfusion phase following 90 minutes of ischemia.

MATERIALS AND METHODS

Cats were injected intravenously with sodium salicylate that by acting as an hydroxyl radical trap, forms 2,3-dihydroxybenzoic acid (2,3-DHBA). Ischemia was achieved by intraocular pressure (IOP) elevation via cannulation of the anterior chamber. Ischemia was maintained for 60 minutes in 6 eyes and 90 minutes in 12 eyes, followed by 5 minutes of reperfusion. In an additional 6 eyes, ischemia was maintained for 90 minutes without reperfusion.

RESULTS

After 90 minutes of ischemia and reperfusion, mean normalized levels of 2,3-DHBA (ie, ng 2,3-DHBA/microg salicylate/mg protein) that represent the levels of hydroxyl radicals were 2.47 times (at least) higher in the anterior optic nerves than in the fellow sham-operated controls (P = 0.03). These levels were 3.9 times (at least) greater than in the corresponding levels after 90 minutes of ischemia without reperfusion (P= 0.005).

CONCLUSION

This study provides a quantitative analysis and evidence for the generation of hydroxyl radicals in the optic nerve of the cat following transient ischemia. A quantitative analysis may provide an important tool to detect even relatively small levels of free radicals in the tissues, and to evaluate the relative efficacy of various therapeutic agents in the inhibition of free radical generation following ischemia and reperfusion.

Mini-trabeculectomy in eyes with high risk of scarring: midterm follow-up

PURPOSE

To report on the surgical outcome after at least 1 year of follow-up of mini-trabeculectomy (without scleral radial incisions), which took place in eyes at high risk of postoperative filtering bleb scarring.

METHODS

In a prospective, institutional study, mini-trabeculectomy was performed on 26 eyes of 26 consecutive patients aged 40 years and older who had undergone a previous intraocular surgery or had had a post-traumatic recessed anterior chamber angle. The surgical procedure, a modification of the standard trabeculectomy, involved a 3-mm fornix-based conjunctival flap, sclerostomy at 1 mm from the limbus, and a sclerocorneal tunnel without radial incisions. During surgery, 0.4 mg per ml of mitomycin C was applied in the scleral pocket of each eye for 3 minutes. Of the 26 eyes, each of two eyes underwent an intraocular intervention during the first postoperative year and therefore was evaluated only for surgical complications. Another eye underwent inferior mini-trabeculectomy, and three other eyes did not complete 12 months of follow-up. Twenty eyes have completed 12 months or more of follow-up and were included in the midterm calculations of intraocular pressure control.

RESULTS

Mean preoperative intraocular pressure (n = 20) was 32.2 +/- 9.5 mm Hg with 3.3 +/- 0.9 hypotensive medications. After 12 to 37 months (mean, 22.1 +/- 6.6) of follow-up, intraocular pressure was 20 mm Hg or less in 18 of 20 eyes (90%) and the mean intraocular pressure was 17.4 +/- 2.9 mm Hg (range, 12 to 23) with 1.1 +/- 1.2 hypotensive medications (range, 0 to 4). At that time, the filtering bleb was low and fleshy in appearance in 15 eyes (75%). Postoperative complications of the 22 eyes included early postoperative aqueous leakage in one eye (4.5%); cataract extraction took place in one eye and vitrectomy was performed in another eye, 7 and 3 months postoperatively, respectively. The four eyes that were excluded from the study had controlled intraocular pressure at the last examination.

CONCLUSION

Mini-trabeculectomy in eyes with high risk of scarring was found efficacious and relatively safe. The relatively small peritomy, the tunnel approach, and the avoidance of radial incisions seem to offer important advantages over the standard trabeculectomy.

Noncontact tonometry in perforating corneal injuries

PURPOSE

To report on one of the possible complications induced by puff noncontact tonometry and to discuss various aspects such as safety, other optional methods, rationality, and the need for tonometry in cases of perforating corneal injuries.

PATIENTS AND METHODS

We report a case of traumatic, self-sealed, midperipheral corneal perforation, where puff tonometry was performed upon admission, 30 minutes after the injury.

RESULTS

The integrity of the wound was temporarily distorted by the air-jet of the puff tonometer, the wound was opened, and an air-bubble filled the anterior chamber.

CONCLUSION

Puff tonometry in patients with self-sealed midperipheral corneal perforation and a negative Seidel test does not seem sufficiently safe during the immediate posttraumatic period.

Needling with intra-bleb 5 fluorouracil for intractable neovascular glaucoma

BACKGROUND AND OBJECTIVE

Trabeculectomy for neovascular glaucoma (NVG) often results in filtering bleb scarring. The outcome of a needling procedure with intra-bleb 5-fluorouracil (5-FU) administration in NVG eyes is presented.

PATIENTS AND METHODS

Following trabeculectomy with mitomycin C (MMC), intraocular pressures (IOPs) ranged between 36 to 56 mm Hg in 3 painful, neovascular glaucomatous eyes despite treatment. Each eye was then injected subconjunctivally with 1.0 mg of 5-FU, adjacent to and within the filtering bleb. The needle was advanced and penetration into the anterior chamber through the bled, anterior to the scleral flap, followed.

RESULTS

In each eye, the IOP dropped immediately. After 18 to 29 months, IOPs were 11 to 22 mm Hg, and in two eyes-without hypotensive medications. Cataract progression was evident in the 2 eyes that had had cataracts preoperatively.

CONCLUSION

The postoperative needling, in conjunction with the dual effect of intraoperative MMC and intra-bleb 5-FU, was found efficacious and saved further surgery in these intractable cases.

Surgical outcome after early intraocular pressure elevation following combined cataract extraction and trabeculectomy

BACKGROUND AND OBJECTIVES

We report on the incidence and course of early postoperative intraocular pressure (IOP) elevation and related surgical outcome following combined manual extracapsular cataract extraction (ECCE), using a sclerocorneal tunnel incision and trabeculectomy.

PATIENTS AND METHODS

The combined procedure was the initial surgery in each eye. Intraocular pressure was measured during the first 4 days, at 1 week, and thereafter following surgery.

RESULTS

Of 38 eyes (38 consecutive adults), postoperative IOP elevation to > 25 mm Hg was found in 7 eyes (18.4%) during the first 3 postoperative days. The IOP was reduced to < or = 20 mm Hg without hypotensive medication in 3 of them within the first 3-7 postoperative days, and remained so after 7-16 months (mean, 10.3 +/- 4.9 months). Each of the other 4 eyes underwent argon-laser suture lysis 8-10 days after surgery due to unstable IOP which rose to > 30 mm Hg. Two weeks after the operation and thereafter, ie, after 8-22 months (mean, 12.8 +/- 6.4 months), each of these 4 eyes necessitated 1-4 (mean, 2.5 +/- 1.3) hypotensive medications.

CONCLUSION

This study raises the possibility that in eyes with early IOP elevation, a delay in promoting aqueous outflow beyond a critical period during the first postoperative week might become a risk factor for full surgical success.

Mini-trabeculectomy without radial incisions

PURPOSE

To describe a new modification of Cairns trabeculectomy.

METHODS

Surgical adjustment includes a small, 3-mm, fornix-based conjunctival flap, a circumferential scleral incision at a distance of only 1 mm from the corneoscleral limbus, and a sclerocorneal tunnel without scleral radial incisions.

RESULT

Among the various clinical and technical advantages of the procedure is the possibility of performing more operations through the superior limbus rather than reverting to an inferior trabeculectomy or implantation of an aqueous shunt.

CONCLUSION

The reduced surgical area and manipulations of the current procedure appear to offer advantages over the standard approach.

Protection of the transiently ischemic cat retina by zinc-desferrioxamine

PURPOSE

A previous study indicated that hydroxyl radicals are generated in the cat retina during the early reperfusion phase after 90 minutes of ischemia. Salicylate was injected intravenously, and its conversion to 2,3-dihydroxybenzoic acid (2,3-DHBA) served as a marker of hydroxyl radicals. The authors attempted to prevent this free radical generation during reperfusion.

METHODS

After salicylate administration, both eyes (15 minutes apart) of 15 cats were subjected to 90 minutes retinal ischemia. Following 5 minutes of reperfusion in the control eye, it was enucleated and processed for DHBA quantitation. Then, 7.5 mg of Zn-desferrioxamine (Zn-DFO) was injected intravenously into nine cats and saline into six cats. Five minutes later, reperfusion was induced in the experimental eye for 5 minutes, followed by enucleation. In one eye each of 12 other cats, scotopic electroretinographic (ERG) studies were carried out during 90 minutes of ischemia and 16 to 18 hours of reperfusion. Five minutes before termination of the ischemia, six animals were injected with 7.5 mg Zn-DFO and six with saline.

RESULTS

The normalized levels of 2,3-DHBA were lower in the experimental eyes than in their fellow controls only after Zn-DFO treatment (P = 0.01). In the ERG studies, after 16 to 18 hours of reperfusion, the mean b-wave-ERG amplitudes in the eyes of the saline-treated cats (n = 6) were 8.4% +/- 4.0% of the preischemic stage, and 70.5% +/- 6.7% of the Zn-DFO-treated cats (n = 6, P = 0.004).

CONCLUSIONS

Protection of the cat retina against ischemia and reperfusion injury by Zn-DFO was evident, most probably through its inhibitory effect on the generation of hydroxyl radicals during reperfusion.

Filtering surgery with 5-fluorouracil subsequent to Molteno implant

In cases of refractory glaucoma, when Molteno shunt implantation has been performed and resulted in failure, the best surgical option has not yet been established. Filtering surgery with 5-fluorouracil (5-FU) as one option for the above was performed in four non-neovascular glaucomatous eyes (four patients) after failure of Molteno shunt implantation. Injections of 5 mg 5-FU were administered once daily for 9-14 days. After follow-up of 6-18 months in 3 eyes, intraocular pressure ranged from 10 to 16 mm Hg. In the fourth eye, in which bleb scarring ensued, a second filtering surgery with 5-FU was performed after 4 months, and resulted in a successful outcome as recorded 26 months later. These preliminary results suggest that filtering surgery with 5-FU might be an acceptable surgical option in non-neovascular refractory glaucoma subsequent to failure of Molteno shunt implantation.

5-fluorouracil and mast cell precursors in mice

In the mouse hematopoietic system, 5-fluorouracil (5-FU) reversibly inhibits the generation of multilineage colonies containing granulocyte, erythroid, megakaryocyte, and macrophage lineage. To determine the effect of 5-FU on mastopoiesis in vitro, bone marrow cells were obtained from mice, cultured, and treated with 5-FU for 14 days in an interleukin-3 (IL-3)-enriched medium. A dose-related inhibitory effect of 5-FU on mastopoiesis was found. When an inhibitory dose (1 microgram/mL) of 5-FU was supplemented to the cultures for only 2, 4, or 8 days and the cells were then recultured without the drug, we observed inhibition of mastopoiesis directly related to the time of exposure of the cells to 5-FU. To determine the effect of 5-FU on mastopoiesis in vivo, bone marrow cells from mice that had received a single intravenous (i.v.) 5-FU injection (150 mg/kg) were cultured. A virtually total absence of mast cells was noted at days 1 and 2 following 5-FU administration. A gradual reappearance of mast cells was later observed. Whether mice were injected with the drug once or with four once-daily (100 mg/kg 5-FU) injections, a similar pattern of delay of mast cell appearance was observed. The findings suggest (1) an irreversible, nonadditive, toxic effect of 5-FU on mast cell precursors and (2) that most or all of the mast cell precursors are nonquiescent cells, continuously activated or cycling. In addition, the use of 5-FU may serve as a unique model system for controlling and studying mastopoiesis in normal mice, rather than the mutated mice currently studied.

Hydroxyl radical generation in the cat retina during reperfusion following ischemia

There is increasing evidence that oxygen-derived free radicals are generated during the early phase of reperfusion, and account for part of the damage caused by transient ischemia in various tissues. To study this in the retina, cats were injected intravenously with sodium salicylate (100 mg kg-1), which reacts as a hydroxyl radical trap to form 2,3- and 2,5-dihydroxybenzoic acids (DHBA). Thirty minutes following injection, the retina of one eye of each animal was subjected to ischemia by intraocular pressure elevation via cannulation of the anterior chamber, while the fellow eye served as a sham-operated control. Ischemia was induced for 60 min (six eyes) and 90 min (eight eyes) followed by 5 min of reperfusion. In six other eyes, ischemia was induced for 90 min without reperfusion. After enucleation, the retinas were immediately removed, placed in ice-cold buffer and the retinal levels of 2,3- and 2,5-DHBA were quantitated by high pressure liquid chromatography, coupled with electrochemical detection. Results were normalized and expressed as ng DHBA microgram-1 salicylate mg-1 retinal protein. After 60 min of ischemia followed by reperfusion the normalized levels of 2,3- and 2-5-DHBA were no different in the experimental and control retinas. However, the levels of both 2,3- and 2,5-DHBA were significantly higher in the retinas subjected to 90 min ischemia followed by reperfusion than in the control tissues (P = 0.012 and P = 0.036, n = 8 respectively). Following 90 min ischemia without reperfusion, the normalized dihydroxybenzoate levels in the retinas were no higher than in their controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Late complications after glaucoma filtering surgery with adjunctive 5-fluorouracil

We studied 105 patients (105 eyes) operated on for glaucoma with adjunctive fluorouracil, who were followed up for 12 to 48 months (mean, 34.6 +/- 12.9 months). Fifty eyes that had previous glaucoma or cataract extraction or had inflammatory glaucoma had a high risk for postoperative scarring (high-risk group), and 55 eyes had glaucoma surgery as an initial procedure (initial surgery group). An intraocular pressure of 20 mm Hg or less, with or without hypotensive medications, was found in 42 eyes in the high-risk group (84.0%) and in 53 of the eyes in the initial surgery group (96.4%). Of the 105 eyes, an intraocular pressure of 12 mm Hg or less without medication was achieved in 17 eyes in the high-risk group (34.0%) and in 35 eyes in the initial surgery group (63.6%). Late complications in both groups were as follows: endophthalmitis in four eyes (3.8%) (two of the infected blebs were located superiorly and two inferiorly), transient leaking bleb in two eyes (1.9%), hypotony of an extended period with 180 to 360 degrees of filtration in three eyes (2.9%), giant bleb extending over the cornea in two eyes (1.9%), and a transient, mild iridocyclitis in nine eyes (8.6%). Thus, adjunctive fluorouracil after filtering surgery may entail various, mainly bleb-related, late side effects and complications.

Trabeculectomy with 5-fluorouracil subsequent to circular buckling operation and cataract extraction

Six patients, each with one eye that had previously undergone circular buckling surgery for the repair of retinal detachment before or followed by cataract extraction with or without intraocular lens implantation, underwent trabeculectomy with 5-fluorouracil (5-FU) for intractable glaucoma. Surgery was done through scarred subconjunctival tissues that were excised partially. The total doses of 5-FU ranged from 65 to 100mg (mean +/- standard deviation, 84.2 +/- 13.2mg) Eight to 47 months later, intraocular pressures were 18mmHg in five eyes, two of which were not receiving hypotensive medications. In the sixth eye, the intraocular pressure was 26mmHg with maximum hypotensive treatment. Intraocular pressures in the six eyes were significantly lower postoperatively than preoperatively (P < .05). This preliminary study suggests that filtering surgery with 5-FU may be beneficial after intraocular operations even in eyes where it is done through postoperative scarred subconjunctival tissues.

A randomized study of trabeculectomy and subconjunctival administration of fluorouracil in primary glaucomas

Forty-one adult patients with primary open angle glaucoma and nine adult patients with chronic angle closure glaucoma underwent trabeculectomy in one eye each. Twenty-one eyes with primary open angle glaucoma and four with chronic angle closure glaucoma were randomly assigned to receive four to six subconjunctival injections of fluorouracil for 10 days after surgery. Twenty-five control eyes did not receive fluorouracil. Intraocular pressure was 20 mm Hg or lower in 24 eyes (96%) in the treatment group after mean follow-up of 17.8 months and in 19 control eyes (76%) after mean follow-up of 17.5 months (P less than .05). Encapsulated bleb developed in three (12%) of the fluorouracil-treated eyes vs two (8%) of the control eyes. A few injections of fluorouracil adequately inhibited scarring. This might be explained by its toxic effect on existing fibroblasts. Overall, trabeculectomy with injection of fluorouracil was found to be efficacious and relatively safe. Further studies regarding late complications are required.

Encapsulated filtering bleb. A selective review--new deductions

Filtering bleb encapsulation may, in some cases, be a severe complication following filtering surgery. The cause and mechanism of its development are not known. A selective review of data that might shed some light on these dilemmas, is presented. Based on these data, it is suggested that: (a) non-contractile collagen-producing fibroblasts play a major role in the process of bleb encapsulation, while in wound healing following filtering surgery, contractile fibroblasts are the major components; (b) the process of bleb encapsulation is less sensitive to the toxic effect of 5-Fluorouracil than would healing; (c) collagen-producing fibroblasts may be less sensitive to the destructive effect of 5-Fluorouracil than contractile fibroblasts; (d) inflammatory mediators are important triggers of bleb encapsulation.

Changes in Müller cell plasma membrane specializations during subretinal scar formation in the rabbit

The aim of this study was to identify changes in Müller cell plasma membrane specializations during experimentally induced subretinal gliosis in rabbits. When rabbits are dosed with sodium iodate, large expanses of retinal pigment epithelium and photoreceptors are destroyed. They are replaced by a subretinal scar consisting mainly of the ascending processes of Müller cells. These processes transform from the slender, highly polarized structures seen in normal animals into irregular processes that form a glia limitans along the basement membrane of the pigment epithelium, left bare following its degeneration. As the scar processes extend through the subretinal space and contract this basement membrane, they undergo dramatic changes in shape that are especially apparent in three-dimensional computer reconstructions of serial thick sections examined by high-voltage electron microscopy. Other changes involve the intercellular junctions and apical microvilli normally associated with the external limiting membrane. These structures become scattered over the surfaces of the ascending processes and are eventually lost. Loss of microvilli is associated with disappearance of immunostaining for a specific glycoconjugate normally associated with the microvillar plasma membrane. The observations document profound changes in Müller cell structural and functional polarity during subretinal scar formation.

Encapsulated filtering bleb and subconjunctival 5-fluorouracil

Filtering bleb encapsulation (BE) involves fibroblast proliferation and collagen synthesis. We analyzed the effect of 5-fluorouracil (5-FU) on the inhibition of BE. Forty-one patients with primary open-angle glaucoma underwent trabeculectomy in one eye as an initial surgery. Twenty-one of these eyes, randomly chosen, were treated postoperatively with four to six 5-FU subconjunctival injections over 10 days to inhibit bleb scarring; the remaining 20 eyes did not receive 5-FU. After 12 to 24 months, the surgical success rate was significantly higher in the treated eyes (P less than .05). However, the incidence of BE was similar: two eyes (9.5% and 10%, respectively) in each group. The difference between the effect of 5-FU in the inhibition of BE and bleb scarring suggests that the characteristics of the two fibroblast populations are heterogeneous.

A possible role of free radicals in the transplantation of retinal pigment epithelial cells

Oxygen-derived free radicals have been implicated in tissue injury following ischemia and reperfusion (reoxygenation). It has been hypothesized that the radicals are produced during the early reperfusion stage. Recently, submacular implantation of retinal pigment epithelium cells has been reported. It is probable that during the procedure, the transplant and the 180-degree folded outer retina underwent a period of ischemia, followed by reoxygenation. We, therefore, infer that free radicals were produced during the reoxygenation stage of the procedure, injuring both tissues. We suggest that these hypotheses be investigated with the aim of improving the surgical outcome in eyes with age-related macular degeneration.

Toxic effects of 5-fluorouracil on fibroblasts following trabeculectomy

The inhibitory effect of 5-fluorouracil (5-FU) on fibroblast proliferation is well established. In addition, toxic effects of 5-FU on existing fibroblasts, in rabbits and in vitro, were demonstrated. We examined human subconjunctival scar tissue which was removed during Molteno tube implantation. Surgery was performed 9 weeks after filtering surgery with 5-FU that resulted in bleb scarring. In the tissue, intracytoplasmic vacuoles were detected in some myofibroblasts, with no visible collagen in their vicinity. This presumed toxic effect of 5-FU may be one explanation for the adequacy of fewer than twice 5-FU injections daily following filtering surgery, and for less than 14 days, as originally recommended for inhibiting bleb scarring.

[Treatment of anterior uveitis with 5-fluorouracil]

Filtering surgery with use of 5-fluorouracil (5FU) was performed in 5 eyes (4 patients) with inflammatory glaucoma to prevent filtering bleb scarring. Postoperative injections of 5FU were given once or twice a day, according to the degree of anterior chamber inflammation. Complete remission of the uveitis was achieved in all 5 eyes after 7-14 days of postoperative injections of 5FU. There were no recurrences of uveitis during a minimum of 8 months of follow-up.

Delayed filtering bleb encapsulation

Encapsulated filtering blebs concomitant with increased intraocular pressure (IOP) developed 47 and 6 months, respectively, after surgery in two women, 46 and 60 years old, respectively, who had undergone trabeculectomy operations in one eye. Both blebs were associated with mild anterior uveitis. Following treatment with topical steroids, cyclopentolate, hypotensive medications, and digital massage, the uveitis resolved and the IOP fell. The likely cause of these late-appearing encapsulated blebs was anterior uveitis.

Effects of 5-fluorouracil on proliferating fibroblasts in vivo

5-Fluorouracil (5-FU) is a potent inhibitor of the proliferation of fibroblasts, the main cell mediators of scar formation. The mechanism of the toxic effect of 5-FU on cancer cells is well known but unclear in nonmalignant cells. The histopathological effects of 5-FU on proliferating fibroblasts in vivo, 2 and 4 weeks after drug injection, are demonstrated here. An insertion of homologous fibroblasts into rabbits' vitreous followed by one injection of 1 mg 5-FU causes intracytoplasmic accumulation of vacuoles, morphological changes and inhibition of collagen deposition in the matrix.

Regulating the dose of 5-fluorouracil to prevent filtering bleb scarring

Repeated doses of 5mg of 5-fluorouracil (5-FU) were injected subconjunctivally in 25 poor-prognosis glaucomatous eyes after filtering surgery to prevent filtering bleb scarring. The frequency (1-2 times a day) and duration (minimum, 7 days) of injections were determined by the degree of the anterior chamber reaction and/or conjunctival hyperemia at the filtering bleb site. Punctate corneal erosions or filaments were not considered a contraindication to continuation of 5-FU treatment. After 12 months, intraocular pressure (IOP) of 16 mmHg or less without medical treatment was found in 19 (76%) eyes. In 16 of these (64%), the IOP was 12 mmHg or less. In two (8%) other eyes, it was 20 mmHg or less with medication. We believe that the comparatively low IOP levels achieved without medical treatment in 76% of the eyes in our study can be attributed in part to our therapeutic approach with 5-FU.

Further observations on the prevention of experimental proliferative vitreo-retinopathy by 5-fluorouracil

The rate of retinal detachment in fellow control eyes of rabbits following fibroblast administration is progressively lower with increased dose of 5-Fluorouracil in the test eyes. Thus, it seems mandatory to choose control eyes in other animals rather than the fellow eyes of the treated ones. Retinal detachment appeared in the second week or earlier after intravitreal fibroblast administration. However, in eyes treated intravitreally with 5-Fluorouracil, retinal detachment or pucker appeared later, even in the second month suggesting routine follow-up of at least 2 months in future studies.

[Prevention of scarring of filtering bleb by 5-fluorouracil]

Scarring of the filtering bleb is the most common cause of failure of surgery for glaucoma. It is much more common when the surgery is for certain types of glaucoma, such as aphakic glaucoma, cases of previously failed filtering surgery and neovascular and uveitic glaucoma. In 31 such high-risk cases we injected 5-fluorouracil subconjunctivally for 7-16 days after operation to prevent scarring of the filtering bleb. The success rate was 83%. After a follow-up of 3-12 months, there was statistically significant improvement in each group as compared to cases in which the drug was not administered. Further indications should be considered for the use of 5-fluorouracil in glaucoma.

Filtering surgery with 5-fluorouracil: a second course

In five glaucoma patients, a previous filtering surgery that was followed by sub-conjunctival injections of 5-Fluorouracil (5-FU) failed, due to filtering bleb scarring. A repetition of the filtering surgery with subsequent sub-conjunctival injections of 5 mg of 5-FU, administered once daily for 8-14 days, was undertaken. At the end of 6-19 months of follow-up, IOP levels in all five eyes were 20 mmHg or less with medication. A repeated course of filtering surgery plus 5-FU treatment seems to be a favourable surgical option in refractory glaucoma.

5-fluorouracil: new applications in complicated retinal detachment for an established antimetabolite

Long-term reattachment of the retina following the development of proliferative vitreoretinopathy is often prevented by the occurrence of cellular reproliferation. 5-fluorouracil, a synthetic pyrimidine analog, is a potent inhibitor of fibroblast proliferation in cell culture and an animal model of tractional retinal detachment. Doses of up to 1.0 mg, when administered intravitreally to rabbits, result in no demonstrable retinal toxicity by microscopic and electrophysiologic criteria. The first 22 consecutive patients with advanced forms of proliferative vitreoretinopathy were treated with a combination of periocular and intraocular 5-fluorouracil, in addition to scleral buckling and vitrectomy. Retinal reattachment was achieved in 60% of patients at 6 months postoperatively. No serious systemic or ocular complications were observed although delayed healing of corneal epithelial defects occurred in 18% of cases and subtle subepithelial scarring in 31.8%. In combination with standard vitrectomy techniques, post-operative fluid gas exchange, and photocoagulation, periocular and subconjunctival 5-fluorouracil appears to improve the prognosis for longterm retinal reattachment following the development of proliferative vitreoretinopathy.

Fluorouracil for the treatment of massive periretinal proliferation

A single intravitreal injection of fluorouracil was effective in the treatment of an experimental model of massive periretinal proliferation. When given with an intravitreal injection of 250,000 heterologous fibroblasts, fluorouracil decreased the rate of tractional retinal detachment from 36.8% in controls (seven of 19 eyes) to 5.2% in treated animals (one of 19 eyes) at one week, and from 73.6% in controls (14 of 19 eyes) to 31.5% in treated animals (six of 19 eyes) after four weeks (P less than .05). Intraocular neovascularization was reduced from 52.6% in controls (ten of 19 eyes) to 5.2% in treated animals (one of 19 eyes) after one week and 36.8% in controls (seven of 19 eyes) to 5.2% in treated animals (one of 19 eyes) after four weeks. When supplemented by repeated 10-mg subconjunctival injections of fluorouracil, or in combination with intravitreally administered indomethacin, this effect appeared to be enhanced. Intravitreal and subconjunctival injections of fluorouracil were well tolerated and may prove to be of significant value in the treatment of human disease.

Experimental intraocular proliferation and neovascularization

An experimental model of massive periretinal proliferation and intraocular neovascularization, produced in rabbits by the intravitreal injection of 250,00 cultured heterologous fibroblasts, showed no significant difference in the detachment rate (69% to 100%) or neovascularization rate (45% to 88%) between the animals injected with autologous cells and those injected with heterologous cells. Dermal fibroblasts produced a slightly higher detachment rate than conjunctival fibroblasts and were equally effective after reconstitution and subculture from liquid nitrogen storage in 7% dimethyl sulfoxide. Heterologous cells produced no clinical or histologic evidence of rejection when compared with autologous cells in the same animal and had the following advantages: (1) elimination of several biopsies and extended cell culture time; (2) a ready source of cryopreserved cells is available; (3) multiple injections of many animals can be performed within a short time; (4) in vivo and in vitro drug testing can be correlated on the same cell line.

Cervical incompetence: diagnostic and therapeutic aspects

During a seven-year period, 311 women with cervical incompetence were treated by cerclage. Fifty-three of the women were treated twice during the study period, 12, three times, and one, four times, so that a total of 391 pregnancies was studied. There were only 45 emergency procedures. Candidates for elective cerclage were selected on the basis of hysterographic findings and the Hegar test. Cerclage was performed by the simple McDonald procedure, usually during the 11th to 12th week of gestation, after the presence of fetal life had been established by ultrasonic detection of the fetal heartbeats. Apart from antibiotics no medical treatment was given. Hospitalization following cerclage was reduced to less than 24 h. The fetal salvage rate was 89%, with minor differences among four etiologic subgroups. The minimum benefit rate of the operations was 64.6%. The degree of cervical patency, as established by the Hegar test, was found to be of prognostic value in cerclage-treated pregnancies. Ultrasonic detection of fetal heartbeat before cerclage significantly improved fetal salvage by almost complete elimination of early fetal loss. Simplification of the surgical procedure is recommended.