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PubMed2002

Environmental controls in operating theatres.

Surgical-site infection is the leading complication of surgery. Normal skin flora of patients or healthcare workers causes more than half all infections following clean surgery, but the importance of airborne bacteria in this setting remains controversial. Modern operating theatres have conventional plenum ventilation with filtered air where particles >/=5 microm are removed. For orthopaedic and other implant surgery, laminar-flow systems are used with high-efficiency particulate air (HEPA) filters where particles >/=0.3 microm are removed. The use of ultra-clean air has been shown to reduce infection rates significantly in orthopaedic implant surgery. Few countries have set bacterial threshold limits for conventionally ventilated operating rooms, although most recommend 20 air changes per hour to obtain 50-150 colony forming units/m(3) of air. There are no standardized methods for bacterial air sampling or its frequency. With the use of HEPA filters in operating theatre ventilation, there is a tendency to apply cleanroom technology standards used in industry for hospitals. These are based on measuring the presence of particles of varying sizes and numbers, and are better suited than bacterial sampling. Environmental bacterial sampling in operating theatres should be limited to investigation of epidemics, validation of protocols, or changes made in materials which could influence the microbial content.

Air Microbiology↗
PubMed2006

Bacterial contamination of filtered intraoral bone chips.

Intraoral bony defects can be filled with bony particles that are collected in a titanium filter. The aim of this study was to determine quantitatively and qualitatively the degree of this contamination. Over a period of 3 months, bony particles were collected from 50 patients undergoing oral surgery. The bony particles were scraped off the filter, resuspended, and incubated aerobically and anaerobically on human blood agar media. Colony forming units (CFU) were determined as well as the most common species of bacteria. All samples showed anaerobic and aerobic growth. After anaerobic incubation in 44 samples the number of bacteria was higher (38) or equal (six) to that after aerobic incubation. On average, 435,000 CFU (aerobic) and 1,013,000 CFU (anaerobic) per sample were found. The most frequently identified bacteria belonged to Veillonella spp. in the anaerobic and to Streptococcus oralis in the aerobic cultures. In 43 samples black-pigmented colonies were detected. Only bacteria common in the oral cavity were identified. Prophylactic antibiotic therapy may be indicated when using filtered bony particles for intraoral augmentation procedures.

Adolescent↗
PubMed1990

Repositioning of partially dislodged Greenfield filters from the right atrium by use of a tip deflection wire.

Dislodgement of a Greenfield filter in the right atrium is one of the most serious complications of this procedure. Retrieval of such a misplaced filter may require surgical intervention by means of cardiopulmonary bypass surgery, which is very hazardous in these often severely ill patients. We describe two cases in which the filter became partially dislodged from its carrier in the right atrium. We were able to successfully reposition the filter by using a tip deflection wire, thereby obviating the need for an open cardiac procedure.

Adult↗
PubMed2007

A prospective long-term study of 220 patients with a retrievable vena cava filter for secondary prevention of venous thromboembolism.

BACKGROUND: The immediate and long-term clinical events associated with the placement and removal of a retrievable filter (ALN filter; ALN Implants Chirurgicaux; Ghisonaccia, France) remain largely unknown. METHODS: This was a prospective cohort study with an 18-month follow-up. All consecutive patients scheduled for placement of an ALN filter between April 1999 and June 2005 in the Radiology Department of our hospital were included. RESULTS: During the study period, placement of an ALN filter was indicated in 220 patients (mean age, 70.8 years), who were followed up for a median duration of 338.5 days (range, 1 to 561 days); 148 patients (67.3%) completed the 18-month follow-up. No patients were unavailable for follow-up. All patients had an acute or past venous thromboembolism. Main indications were recurrent venous thromboembolism despite adequate anticoagulation therapy (10.9%), transient bleeding event (21.8%), definitive contraindication for anticoagulant therapy (26.8%), or obligation to stop anticoagulant therapy due to major surgery, major trauma, or invasive procedure (37.7%). Filter insertion was successful in 98.6% of patients and resulted in an immediate complication in 11.8%. The median duration of filter implantation was 166 days (first to third quartiles, 34 to 478 days). Meanwhile, 17.0% (37 of 217 patients) had at least one venous thromboembolic event. Filter retrieval was attempted in 25.3% of patients after a median of 51 days (range, 6 to 352 days); removal was successful at the first attempt in 92.7% of patients. CONCLUSIONS: The filter could be easily inserted and successfully removed up to 1 year after insertion. Its safety and efficacy in preventing pulmonary embolism should be properly assessed in a randomized study.

Adult↗
PubMedDate not supplied

[Prevention of risk of cross-infection through the respiratory system during anesthesia].

The authors present a modern concept of prevention of cross contamination during forced ventilation of the lungs in the course of total anesthesia and operation. The optimal complex of measures of individual protection of a patient includes hygienic measures, use of sterile respiratory systems (better disposable), obligatory use of respiratory filters between the intubation tube and T-piece of the narcosis and respiration device; hydrophobic folded membrane filters should be preferred. Studies carried out at Anesthesiology Department of Research Center of Surgery of Russian Academy of Medical Sciences indicate that BB 22-15 filters (Pall Corporation) reliably protect patients from cross-contamination realized through respiratory gases and biological fluids (blood, saliva, condensate) and save heat and humor. Hydrophobic folded membrane filter BB 22-15 is highly effective, which recommends it for wide use.

Adult↗
PubMed1999

[Initial clinical experience with deep sclerectomy in ambulatory surgery in glaucoma].

Deep sclerectomy is a non-perforating filtering operation used in surgical treatment of open angle glaucomas. The advantage of the operation is the creation of gradual filtration due to the thin trabecular Descement membrane which reduces markedly the risk of development of postoperative complications typical for perforating antiglaucomatous operations. The authors operated at the out-patient department 10 eyes of 8 patients (age 46-81 years). Indications for deep sclerectomy was seven times primary open angle glaucoma (POAG), once capsular glaucoma and twice normotensive glaucoma (NTG). In all eyes deep sclerectomy was indicated because of decompensation of the intraocular pressure with maximum tolerated therapy before surgery. None of the eyes were operated previously. The mean value of intraocular pressure before surgery was 25.1 +/- 6.5 mm Hg. From the results ensues that in nine operated eyes the intraocular pressure at the end of the 6-month follow-up period was compensated without supplementary therapy, only in one eye beta-blockers were prescribed one month after surgery. The cause of failure of filtration was the development of superficial adherence at the site of microperforatiion of the trabecular Descemet membrane which developed during operation. The mean intraocular pressure values at the end of the investigation period were 14.3 +/- 2.8 mm Hg. In two eyes haemorrhage into the anterior chamber was observed on the first day after surgery, the blood was absorbed within 24 hours. Hypotonia in two eyes was only transient and was not associated with a change in the depth of the anterior chamber or other complications. In none of the patients a decline of visual acuity was observed. In three operated eyes a change of refraction was necessary due to discontinuation of miotics after surgery. Deep sclerectomy is a delicate microsurgical technique which calls for experience and skill of the surgeon. The most complicated task is to prevent perforation of the trabecular Descemet membrane during surgery. Provided the surgical technique is perfect, it burdens the patient less than commonly performed perforating antiglaucomatous operations and it can be implemented in the out-patient department.

Adult↗
PubMed2005

Enhance postoperative filtering bleb-induced vision difficulties with well-fitted GP contact (oxygen-permeable) lenses.

BACKGROUND: Occasionally contact lenses need to be fit on patients with filtering blebs. Gas-permeable (GP) lens fitting is still controversial because, although the contact lens can improve visual acuity and satisfy a patient's visual need, it can also compromise the bleb and increase the risk of ocular infection. METHODS: A retrospective review of charts evaluated patients wearing a GP contact lens a minimum of two months after trabeculectomy surgery. Seven optometrists and one ophthalmologist submitted data on 20 eyes (15 subjects). Success of the contact lenses on these eyes was evaluated, as well as patient history and ocular complications from the contact lens. Contact lens success was based on the patient's ability to wear a GP contact lens a minimum of 6 hours a day, at least 4 days a week, without permanent damage or significant compromise to the bleb. RESULTS: GP contact lenses were successfully fit and worn on 17 of 20 eyes with a functioning filtering bleb (85%). Two of the 17 eyes terminated GP contact lens use after a few years for reasons unrelated to contact lens wear. Three eyes (15%) were unsuccessful and discontinued GP contact lens wear. Of the three eyes that were not successful in wearing a GP contact lens, two eyes discontinued wear secondary to contact lens intolerance and one eye discontinued contact lens wear as a result of fitting difficulties. There were no complications of blebitis or endophthalmitis, but two eyes were treated for bleb laceration and staining of the bleb. CONCLUSION: GP contact lenses can be successfully worn in eyes with filtering blebs. However, to reduce the risk of complication and infection, proper fitting guidelines should be followed and patients should return for evaluations at intervals of 6 months or less.

Adolescent↗
PubMed1999

Efficiency and safety of leukocyte filtration during cardiopulmonary bypass for cardiac surgery.

BACKGROUND: Leukocyte filtration of systemic blood during cardiopulmonary bypass surgery to reduce post-operative morbidity has not yet been established because of the enormous leukocyte release from the third space. This study was designed to examine the efficiency and safety of leukocyte filtration by a new prototype large capacity leukocyte filter. PATIENTS AND METHODS: Patients undergoing cardiopulmonary bypass surgery were prospectively divided into two groups: a leukocyte removal group (n = 11) receiving leukocyte filtration during cardiopulmonary bypass and a control group (n = 20) with no filtration. The filtration efficiency was indicated by electronic leukocyte counts before and after filtration and the clinical efficiency to reduce post-operative morbidity was indicated by PaO2. Safety was indicated by monitoring the filtration pressure and leukocyte release products across the filter, as well as by examining the post-filtration filter by light and electron microscopy. RESULTS: On an average, 75% of all entering leukocytes were removed by the filter. The post-operative PaO2 showed a tendency to improve after filtration. During filtration, the pressure across the filter material increased in five cases, accompanied by an increase in post-filter plasma hemoglobin and beta-glucoronidase. Within these filters accumulations of fibrin network with many trapped leukocytes were discovered microscopically. CONCLUSIONS: The filter was efficient in filtering leukocytes, but the filtration efficiency slowed at the end of filtration. Furthermore, the patients' post-operative parameters showed a tendency to improve after filtration. However, flow obstruction by means of clotting seems to be an important issue of safety involved in the filtration of large numbers of leukocytes for cardiopulmonary surgical patients.

Cardiopulmonary Bypass↗
PubMed1992

Vena caval filter use in orthopaedic trauma patients with recognized preoperative venous thromboembolic disease.

This study comprises a series of 35 patients with pelvic or lower extremity fractures requiring surgery who also had a documented significant acute deep venous thrombosis (DVT). The authors treated these with low-dose Coumadin and 36 vena caval filters, which were used prophylactically prior to surgery. The patients received low-dose warfarin after placement of the vena caval filters and were maintained at 1.3-1.5 times the prothrombin control value for 6 weeks to 3 months. In this group of patients, there were no fatal pulmonary emboli and no clinically significant complications from filter placement. There were nine asymptomatic filter complications demonstrated radiographically in eight patients. Additionally, one patient with a tilted vena caval filter required placement of another filter. The combination of vena caval filters and low-dose warfarin appears to be a successful and relatively safe method of managing those patients who have acute DVT and require surgery for their pelvic or lower extremity fractures.

Combined Modality Therapy↗
PubMed2001

Experimental flow studies in glaucoma drainage device development.

AIMS: (I) To examine whether small holes produced by 248 nm excimer laser ablation in a polymer substrate could consistently produce a pressure drop in the desired target range (5-15 mm Hg) at physiological aqueous flow rates for use as an internal flow restrictor in a glaucoma drainage device, and (ii) to investigate whether external leakage could be reduced in comparison with conventional tube and plate glaucoma drainage devices by redesigning the exterior cross sectional shape of the portion contained within the sclerocorneal tunnel. METHODS: Single holes with target diameters of 10 microm, 15 microm, 20 microm, and 25 microm were drilled using a 248 nm excimer laser in sample discs (n=6 at each diameter) punched from a 75 microm thick polyimide sheet. Sample discs were tested in a flow rig designed to measure the pressure drop across the discs. Using filtered, degassed water at a flow rate of 1.4 microl/min repeated flow measurements were taken (n=6) for each disc. After flow testing, all discs were imaged using a scanning electron microscope and the dimensions of each hole were derived using image analysis software. In the external leakage study, corneoscleral buttons (n=13) were prepared from cadaver pig eyes and mounted on an artificial anterior chamber infused with Tyrode solution. After the pressure had stabilised, standard occluded silicone tube implants were inserted through 23 gauge needle stab incisions at the limbus. These were compared against prototype PMMA implants with a novel shape profile inserted through 1.15 mm width microvitreoretinal (MVR) stab incisions at the limbus. The infusion rate was maintained and a second pressure measurement was taken when the pressure had stabilised. The difference between the first and second pressure measurement was then compared, as an index of external leakage. RESULTS: Ablated tubes were found to have a near perfect circular outline on both the entry and exit side. The observed pressure drops across the ablated sample discs at each target diameter were as follows: 10 microm, mean 25.66 (SD 4.9) mm Hg; 15 microm, 6.7 (1.15); 20 microm, 1.66 (1.07); and 25 microm, <0.1 mm Hg. A strong correlation was observed between observed pressure drops and those predicted by Poiseuille's formula (R(2) =0.996). Target ablations of 15 microm diameter produced tubes that consistently achieved a pressure drop within the desired range (5-15 mm Hg). In the external leakage study, preinsertion pressures (mm Hg; mean (SD)) were 19.00 (4.3) (conventional method) and 20.00 (3.9) (new technique with PMMA prototypes). Post-insertion pressures were significantly reduced (10.40 (7.7); p<0.01) for the conventional technique and were essentially unchanged for the new technique (18.80 (4.9); p>0.1). CONCLUSIONS: It was shown that it is possible, in principle, to control the dimensions of a manufactured tubular lumen in a glaucoma drainage device accurately enough to provide consistent protection from hypotony in the early period after glaucoma filtration surgery. By redesigning the external profile of glaucoma drainage device and incision technique, it was also shown that it is possible to eliminate uncontrolled external leakage.

Animals↗
PubMed2005

Retrievable Günther Tulip filter complicated by sepsis and retroperitoneal hemorrhage: successful management by filter retrieval.

We encountered complications of septic shock and retroperitoneal hemorrhage which occurred after implantation of a retrievable Günther Tulip filter. A 79-year-old woman was diagnosed as right femoral vein thrombosis, and a retrievable Günther Tulip filter was deployed prior to a total knee replacement surgery. However, the patient developed septicemia due to Citrobacter freundii, followed by thrombocytopenia and retroperitoneal hemorrhage. A large hematoma was formed along the lateral side of the filter struts. We considered that the filter should be removed to control retroperitoneal hemorrhage and prevent secondary infection of the hematoma. Removal of the retrievable filter was effective in managing these complications.

Aged↗
PubMed1997

Effect of major surgery on neutrophil chemotaxis and actin polymerization in neonates and children.

The authors have examined the effect of major surgery in neonates and older children on neutrophil (PMN) chemotaxis and on actin polymerization, an essential early step in PMN movement. Isolated PMNs from the following subjects were studied: healthy adult volunteers (n = 28), healthy newborns (n = 21), newborns undergoing major surgery (n = 7), and older infants and children undergoing major surgery (n = 14). Chemotaxis was measured by a micropore filter assay, and actin polymerization was measured by flow cytometry. Blood samples from surgical patients were obtained preoperatively, hourly during the procedure, immediately postoperatively, and 48 hours after surgery. Mean preoperative newborn PMN chemotaxis was similar to that of healthy newborn PMN, and mean preoperative PMN chemotaxis in children was similar to that of healthy adults. There were no significant alterations in PMN chemotaxis during or after major surgery in neonates or children. Peak PMN actin polymerization, after stimulation with formyl methionyl leucyl phenylalanine (FMLP) (10 nm), was significantly diminished in healthy neonates compared with adults (P < .005). Preoperative surgical neonates had similar peak PMN actin polymerization levels to those of healthy newborns, and older preoperative children had similar levels to adults. PMN actin polymerization did not significantly change during or after major surgery. Despite reductions in PMN chemotaxis and actin polymerization in healthy neonates, there is no further impairment of these PMN functions during or after major surgery. Our data suggest that PMN chemotactic function is resistant to the stress of uncomplicated major surgery in neonates and children.

Actins↗
PubMedDate not supplied

Transcatheter regional urokinase therapy in the management of inferior vena cava thrombosis.

PURPOSE: To study the efficacy of local infusion of urokinase (UK) in the treatment of symptomatic inferior vena cava (IVC) thrombosis. MATERIALS AND METHODS: Eight patients (five men and three women) who ranged in age from 19 years to 75 years (mean, 56 years) with symptomatic IVC thrombosis underwent local catheter-directed infusion of UK with use of up to three access sites. Infrarenal IVC thrombus and iliac vein thrombus was identified in all patients. Four patients had extension of thrombus proximal to the renal veins. Seven of eight patients had at least one risk factor for IVC thrombosis: hypercoagulable state (n = 3), IVC filter (n = 3), malignancy (n = 2), recent surgery (n = 2), and oral contraceptive use (n = 1). No serious procedure-related complications were encountered, although one patient died 5 days after UK therapy of pulmonary failure due to advanced lung cancer. UK was infused for an average of 79 hours (range, 24-140 hours) and a mean total dose of 7.4 million U of UK (range, 2.9-14.4 million U). Adjunctive balloon angioplasty was performed in three patients. No vascular stents were placed. Clinical and/or radiographic follow-up was obtained in all eight patients. RESULTS: Thrombolysis was successful in seven of eight (88%) IVCs with no or minimal residual thrombus. The remaining seven patients had no lower extremity swelling 2-24 months (mean, 11 months) after the procedure. Three of seven patients had computed tomographic or venographic follow-up (mean, 9 months; range, 1.5-15 months), demonstrating unchanged or improved IVC patency. CONCLUSIONS: Transcatheter regional infusion of UK for re-establishing venous patency in acute IVC thrombosis appears to be effective with good short-term and mid-term clinical benefit.

Adult↗
PubMed2000

[Sclerothalamectomy (STE): stable postoperative intraocular pressure regulation in primary open-angle and pseudoexfoliative glaucoma].

BACKGROUND: Since the 70th years we operated the hemorrhagic glaucoma by a ciliary body exposure after Benedikt. In a few patients we noted a stable intraocular pressure regulation for years, often in these cases where there is no filtering bleb. This signifies, that the ciliary body is heavily involved in the resorption of the anterior chamber fluid. During the following next years we further developed this operating technique and we use it today successfully in the operative treatment of primary open angle- and pseudoexfoliative glaucoma. PATIENTS AND METHODS: Since march 1996 we performed a sclerothalamectomy in 46 eyes. In approximate the half of cases the operation was done combined with a cataract surgery. 27 eyes had a primary open angle and 19 eyes a pseudoexfoliative glaucoma with a mean preoperative intra-ocular pressure of 29.79 +/- 7.96 mm Hg respectively of 33.58 +/- 9.32 mm Hg. RESULTS: The mean follow-up was in the case of primary open angle glaucoma 18.3 +/- 8.9 (median 20) and in the case of pseudoexfoliative glaucoma 15.8 +/- 11 (median 16) months. The mean postoperative intra-ocular pressure, which range in the group of primary open angle glaucoma 13.9 +/- 1.6 mm Hg and in the group of pseudoexfoliative glaucoma 12.9 +/- 2.5 mm Hg, was significant lower with significant less postoperative medication compared with the preoperative values during the complete follow-up (p < 0.01). There was no evidence in a significant difference between the both groups regarding the postoperative complication rate and intra-ocular pressure. We observed altogether in 7 eyes a flat filtering bleb, 5/27 in the primary open angle glaucoma and 2/19 in the pseudoexfoliative glaucoma group. In all of other cases we didn't state a filtering bleb. CONCLUSION: The sclerothalamectomy leeds to a long-term stable intra-ocular pressure with a contemporary low complication rate in the case of primary open angle- and pseudoexfoliative glaucoma.

Exfoliation Syndrome↗
PubMed2004

[Bacterial contamination of bony particles from the bone collection trap].

Intraoral bony defects can be filled with bony particles that are collected in a titanium filter while drilling. The rinsing liquid is contaminated with blood and saliva which implies that the bony particles are also contaminated with bacteria. The aim of this study was to determine quantitatively and qualitatively the degree of this contamination. Over a period of three months bony particles were collected from 50 patients undergoing surgery. The bony particles were scraped off the filter, resuspended and incubated aerobically and anaerobically on human blood agar media. Colony forming units (CFU) were determined as well as the most common species of bacteria. All samples showed anaerobic and aerobic growth. After anaerobic incubation in 44 samples the number of bacteria was higher (38) or equal (six) to that after aerobic incubation. On average 435,000 CFU (aerobic) and 1,013,000 CFU (anaerobic) per sample were found. The most frequently identified bacteria belonged to Veillonella spp. in the anaerobic and to Streptococcus oralis in the aerobic cultures. In 43 samples black pigmented colonies were detected. There were only bacteria identified which are common in the oral cavity.

Adolescent↗
PubMed2001

Results of viscocanalostomy for primary open-angle glaucoma.

PURPOSE: Viscocanalostomy is a nonperforating filtering surgical procedure that may avoid postoperative complications common with standard trabeculectomy. This study was conducted to determine the surgical outcome of this procedure after a postoperative observation period of 12 to 36 months. METHODS: Interventional consecutive case series. In a prospective study, a consecutive series of 67 eyes of 67 patients with chronic primary open-angle glaucoma underwent VCS. Excluded were patients with angle closure glaucoma, post-traumatic, uveitic, neovascular, or dysgenetic glaucoma, as well as patients who needed combined cataract-glaucoma procedures. The patients were examined postoperatively on the first day, first week, at 1 month, and then at 3-month intervals through 36 months. At each visit, best-corrected visual acuity, intraocular pressure (IOP), and the appearance of the surgical wound, anterior chamber, and indirect funduscopy were recorded. RESULTS: Complete success was defined as IOP less than or equal to 20 mm Hg and greater than or equal to 30% IOP reduction without medical or additional surgical treatment compared with the IOP from a preoperative level with maximum tolerated medical therapy; qualified success IOP less than or equal to 20 mm Hg with treatment or an IOP reduction less than 30% from preoperative level with maximum tolerated medical therapy; and qualified failure of an IOP greater than 20 mm Hg with glaucoma medication, but no optic nerve or visual field deterioration and complete failure as an eye requiring further glaucoma surgery or lost visual function. The overall success rate was 88% at 1 year, 90% at 2 years, and 88% at 3 years, with a complete success of 68% at 1 year, 60% at 2 and 59% at 3 years. Four eyes had a perforation of the Descemet membrane, three of those needed peripheral iridectomy; six eyes had a microperforation not needing a peripheral iridectomy. Five eyes presented hyphema. Eight eyes presented deterioration of visual function after surgery: three eyes because of corneal astigmatism, one eye because of cataract, and four presented glaucomatous deterioration of the visual field despite pressures under 20 mm Hg. Four eyes had progressive cataract formation judged as independent from surgery. CONCLUSION: VCS provides an overall success rate of 88% and a complete success of 59% 3 years after surgery. The major immediate complication is perforation of the Descemet membrane with a need for peripheral iridectomy. No serious long-term complications were noted in our small series. Visual function remained stable in 55 eyes (82%).

Aged↗
PubMed1977

Revision of filtration surgery.

Forty-one procedures were performed to revise malfunctioning filtering blebs in 37 eyes. Thirty-two procedures were undertaken on underfiltering blebs, seven on overfiltering blebs, and two on normally functioning but otherwise unsatisfactory blebs. Revision procedures were successful in 24 of 32 underfiltering blebs, four of seven overfiltering blebs, and one of two normally functioning but unsatisfactory blebs.

Adult↗
PubMed1998

Biocompatibility response to modified Baerveldt glaucoma drains.

Glaucoma implants are designed to increase fluid outflow from the eye in order to decrease intraocular pressure and prevent damage to the optic nerve. The implant consists of a silicone tube that is inserted into the anterior chamber at one end and is attached at the other end to a silicone plate that is sutured to the outside of the globe beneath the conjunctiva. The glaucoma "implant" becomes a "drain" over the first 3 to 6 postoperative weeks as the silicone plate is enclosed by a fibrous capsule that allows a space to form into which fluid can drain and from which fluid can be absorbed by the surrounding tissues. Ideally, the size and thickness of the capsule (the filtering bleb) that surrounds the plate is such that the amount of fluid that passes through the capsule is identical to the amount of fluid produced by the eye at an intraocular pressure of 8 to 14 mmHg. The most common long-term complication of these implants is failure of the filtering bleb 2 to 4 years after surgery due to the formation of a thick fibrous capsule around the device. Micromovement of the smooth drainage plate against the scleral surface may be integral to the mechanism of glaucoma implant failure by stimulating low-level activation of the wound healing response, increased collagen scar formation, and increased fibrous capsule thickness. To test this hypothesis, we modified seven Baerveldt implants by adding porous cellular ingrowth material to the posterior surface of the drainage plate. Seven modified and five unmodified implants were placed in adult rabbit eyes. After 6 months, we found that the fibrous capsule around the modified implants was significantly thinner than the capsule surrounding the unmodified implants (p < 0.05), particularly on the surface between the porous ingrowth material and the sclera (p < 0.05). Although type I collagen predominated in the fibrous capsules around both types of implants, the amount of type III collagen in the capsules around the modified implants was significantly less than the amount around the unmodified implants (p < 0.05). We believe that these data suggest a reduction in the wound healing response to the modified implants, with greater stability of capsule thickness. Long-term studies are needed to verify that the stability of the capsules around the modified implants persists over a period of years, in which case this type of modification may prove useful in prolonging the functional life of these devices in the surgical treatment of glaucoma.

Animals↗