Corneal nerves in refractive surgery and dry eye

This study aimed to investigate the morphology and function of corneal sensory nerves in 1) patients after corneal refractive surgery and 2) patients with dry eye due to Sjögren's syndrome. A third aim was to explore the possible correlation between cytokines detected in tears and development of post-PRK subepithelial haze. The main methods used were tear fluid ELISA analysis, corneal in vivo confocal microscopy, and noncontact esthesiometry. The results revealed that after PRK a positive correlation exists between the regeneration of subbasal nerves and the thickness of regenerated epithelium. Pre- or postoperative levels of the tear fluid cytokines TGF-β1, TNF-α, or PDGF-BB did not correlate with the development of corneal haze objectively estimated by in vivo confocal microscopy 3 months after PRK. After high myopic LASIK, a discrepancy between subjective dry eye symptoms and objective signs of dry eye was observed. The majority of patients reported ongoing dry eye symptoms even 5 years after LASIK, although no objective clinical signs of dry eye were apparent. In addition, no difference in corneal sensitivity was observed between these patients and controls. Primary Sjögren's syndrome patients presented with corneal hypersensitivity, although their corneal subbasal nerve density was normal. However, alterations in corneal nerve morphology (nerve sprouting and thickened stromal nerves) and an increased number of antigen-presenting cells among subbasal nerves were observed, implicating the presence of an ongoing inflammation. Based on these results, the relationship between nerve regeneration and epithelial thickness 3 months after PRK appears to reflect the trophic effect of corneal nerves on epithelium. In addition, measurement of tear fluid cytokines may not be suitable for screening patients for risk of scar (haze) formation after PRK. Presumably, at least part of the symptoms of "LASIK-associated dry eye" are derived from aberrantly regenerated and abnormally functioning corneal nerves. Thus, they may represent a form of corneal neuropathy or "phantom pain" rather than conventional dry eye. Corneal nerve alterations and inflammatory findings in Sjögren's syndrome offer an explanation for the corneal hypersensitivity or even chronic pain or hyperalgesia often observed in these patients. In severe cases of disabling chronic pain in patients with dry eye or after LASIK, when conventional therapeutic possibilities fail to offer relief, consultation of a physician specialized in pain treatment is recommended.

Excimer laser refractive surgery : corneal wound healing and clinical results

Although the first procedure in a seeing human eye using excimer laser was reported in 1988 (McDonald et al. 1989, O'Connor et al. 2006) just three studies (Kymionis et al. 2007, O'Connor et al. 2006, Rajan et al. 2004) with a follow-up over ten years had been published when this thesis was started. The present thesis aims to investigate 1) the long-term outcomes of excimer laser refractive surgery performed for myopia and/or astigmatism by photorefractive keratectomy (PRK) and laser-in situ- keratomileusis (LASIK), 2) the possible differences in postoperative outcomes and complications when moderate-to-high astigmatism is treated with PRK or LASIK, 3) the presence of irregular astigmatism that depend exclusively on the corneal epithelium, and 4) the role of corneal nerve recovery in corneal wound healing in PRK enhancement. Our results revealed that in long-term the number of eyes that achieved uncorrected visual acuity (UCVA)≤0.0 and ≤0.5 (logMAR) was higher after PRK than after LASIK. Postoperative stability was slightly better after PRK than after LASIK. In LASIK treated eyes the incidence of myopic regression was more pronounced when the intended correction was over >6.0 D and in patients aged <30 years.Yet the intended corrections in our study were higher for LASIK than for PRK eyes. No differences were found in percentages of eyes with best corrected visual acuity (BCVA) or loss of two or more lines of visual acuity between PRK and LASIK in the long-term. The postoperative long-term outcomes of PRK with two different delivery systems broad beam and scanning laser were compared and revealed no differences. Postoperative outcomes of moderate-to-high astigmatism yielded better results in terms of UCVA and less compromise or loss of two more lines of BCVA after LASIK that after PRK.Similar stability for both procedures was revealed. Vector analysis showed that LASIK outcomes tended to be more accurate than PRK outcomes, yet no statistically differences were found. Irregular astigmatism secondary to recurrent corneal erosion due to map-dot-fingerprint was successfully treated with phototherapeutic keratectomy (PTK). Preoperative videokeratographies (VK) showed irregular astigmatism. However, postoperatively, all eyes showed a regular pattern. No correlation was found between pre- and postoperative VK patterns. Postoperative outcomes of late PRK in eyes originally subjected to LASIK showed that all (7/7) eyes achieved UCVA ≤0.5 at last follow-up (range 3 — 11 months), and no eye lost lines of BCVA. Postoperatively all eyes developed and initial mild haze (0.5 — 1) into the first month. Yet, at last follow-up 5/7 eyes showed a haze of 0.5 and this was no longer evident in 2/7 eyes. Based on these results, we demonstrated that the long-term outcomes after PRK and LASIK were safe and efficient, with similar stability for both procedures. The PRK outcomes were similar when treated by broad-beam or scanning slit laser. LASIK was better than PRK to correct moderate-to-high astigmatism, yet both procedures showed a tendency of undercorrection. Irregular astigmatism was proven to be able to depend exclusively from the corneal epithelium. If this kind of astigmatism is present in the cornea and a customized PRK/LASIK correction is done based on wavefront measurements an irregular astigmatism may be produced rather than treated. Corneal sensory nerve recovery should have an important role in the modulation of the corneal wound healing and post-operative anterior stromal scarring. PRK enhancement may be an option in eyes with previous LASIK after a sufficient time interval that in at least 2 years.

Visual search and eye movements: Studies of perceptual span

In visual search one tries to find the currently relevant item among other, irrelevant items. In the present study, visual search performance for complex objects (characters, faces, computer icons and words) was investigated, and the contribution of different stimulus properties, such as luminance contrast between characters and background, set size, stimulus size, colour contrast, spatial frequency, and stimulus layout were investigated. Subjects were required to search for a target object among distracter objects in two-dimensional stimulus arrays. The outcome measure was threshold search time, that is, the presentation duration of the stimulus array required by the subject to find the target with a certain probability. It reflects the time used for visual processing separated from the time used for decision making and manual reactions. The duration of stimulus presentation was controlled by an adaptive staircase method. The number and duration of eye fixations, saccade amplitude, and perceptual span, i.e., the number of items that can be processed during a single fixation, were measured. It was found that search performance was correlated with the number of fixations needed to find the target. Search time and the number of fixations increased with increasing stimulus set size. On the other hand, several complex objects could be processed during a single fixation, i.e., within the perceptual span. Search time and the number of fixations depended on object type as well as luminance contrast. The size of the perceptual span was smaller for more complex objects, and decreased with decreasing luminance contrast within object type, especially for very low contrasts. In addition, the size and shape of perceptual span explained the changes in search performance for different stimulus layouts in word search. Perceptual span was scale invariant for a 16-fold range of stimulus sizes, i.e., the number of items processed during a single fixation was independent of retinal stimulus size or viewing distance. It is suggested that saccadic visual search consists of both serial (eye movements) and parallel (processing within perceptual span) components, and that the size of the perceptual span may explain the effectiveness of saccadic search in different stimulus conditions. Further, low-level visual factors, such as the anatomical structure of the retina, peripheral stimulus visibility and resolution requirements for the identification of different object types are proposed to constrain the size of the perceptual span, and thus, limit visual search performance. Similar methods were used in a clinical study to characterise the visual search performance and eye movements of neurological patients with chronic solvent-induced encephalopathy (CSE). In addition, the data about the effects of different stimulus properties on visual search in normal subjects were presented as simple practical guidelines, so that the limits of human visual perception could be taken into account in the design of user interfaces.

Routine Measurement of Health-Related Quality of Life in Assessing Cost-Effectiveness in Secondary Health Care

Aims: The aims of this study were 1) to identify and describe health economic studies that have used quality-adjusted life years (QALYs) based on actual measurements of patients' health-related quality of life (HRQoL); 2) to test the feasibility of routine collection of health-related quality of life (HRQoL) data as an indicator of effectiveness of secondary health care; and 3) to establish and compare the cost-utility of three large-volume surgical procedures in a real-world setting in the Helsinki University Central Hospital, a large referral hospital providing secondary and tertiary health-care services for a population of approximately 1.4 million. Patients and methods: So as to identify studies that have used QALYs as an outcome measure, a systematic search of the literature was performed using the Medline, Embase, CINAHL, SCI and Cochrane Library electronic databases. Initial screening of the identified articles involved two reviewers independently reading the abstracts; the full-text articles were also evaluated independently by two reviewers, with a third reviewer used in cases where the two reviewers could not agree a consensus on which articles should be included. The feasibility of routinely evaluating the cost-effectiveness of secondary health care was tested by setting up a system for collecting HRQoL data on approximately 4 900 patients' HRQoL before and after operative treatments performed in the hospital. The HRQoL data used as an indicator of treatment effectiveness was combined with diagnostic and financial indicators routinely collected in the hospital. To compare the cost-effectiveness of three surgical interventions, 712 patients admitted for routine operative treatment completed the 15D HRQoL questionnaire before and also 3-12 months after the operation. QALYs were calculated using the obtained utility data and expected remaining life years of the patients. Direct hospital costs were obtained from the clinical patient administration database of the hospital and a cost-utility analysis was performed from the perspective of the provider of secondary health care services. Main results: The systematic review (Study I) showed that although QALYs gained are considered an important measure of the effectiveness of health care, the number of studies in which QALYs are based on actual measurements of patients' HRQoL is still fairly limited. Of the reviewed full-text articles, only 70 reported QALYs based on actual before after measurements using a valid HRQoL instrument. Collection of simple cost-effectiveness data in secondary health care is feasible and could easily be expanded and performed on a routine basis (Study II). It allows meaningful comparisons between various treatments and provides a means for allocating limited health care resources. The cost per QALY gained was 2 770 for cervical operations and 1 740 for lumbar operations. In cases where surgery was delayed the cost per QALY was doubled (Study III). The cost per QALY ranges between subgroups in cataract surgery (Study IV). The cost per QALY gained was 5 130 for patients having both eyes operated on and 8 210 for patients with only one eye operated on during the 6-month follow-up. In patients whose first eye had been operated on previous to the study period, the mean HRQoL deteriorated after surgery, thus precluding the establishment of the cost per QALY. In arthroplasty patients (Study V) the mean cost per QALY gained in a one-year period was 6 710 for primary hip replacement, 52 270 for revision hip replacement, and 14 000 for primary knee replacement. Conclusions: Although the importance of cost-utility analyses has during recent years been stressed, there are only a limited number of studies in which the evaluation is based on patients own assessment of the treatment effectiveness. Most of the cost-effectiveness and cost-utility analyses are based on modeling that employs expert opinion regarding the outcome of treatment, not on patient-derived assessments. Routine collection of effectiveness information from patients entering treatment in secondary health care turned out to be easy enough and did not, for instance, require additional personnel on the wards in which the study was executed. The mean patient response rate was more than 70 %, suggesting that patients were happy to participate and appreciated the fact that the hospital showed an interest in their well-being even after the actual treatment episode had ended. Spinal surgery leads to a statistically significant and clinically important improvement in HRQoL. The cost per QALY gained was reasonable, at less than half of that observed for instance for hip replacement surgery. However, prolonged waiting for an operation approximately doubled the cost per QALY gained from the surgical intervention. The mean utility gain following routine cataract surgery in a real world setting was relatively small and confined mostly to patients who had had both eyes operated on. The cost of cataract surgery per QALY gained was higher than previously reported and was associated with considerable degree of uncertainty. Hip and knee replacement both improve HRQoL. The cost per QALY gained from knee replacement is two-fold compared to hip replacement. Cost-utility results from the three studied specialties showed that there is great variation in the cost-utility of surgical interventions performed in a real-world setting even when only common, widely accepted interventions are considered. However, the cost per QALY of all the studied interventions, except for revision hip arthroplasty, was well below 50 000, this figure being sometimes cited in the literature as a threshold level for the cost-effectiveness of an intervention. Based on the present study it may be concluded that routine evaluation of the cost-utility of secondary health care is feasible and produces information essential for a rational and balanced allocation of scarce health care resources.

Molecular genetics of X-linked cone-rod dystrophy and Åland Island eye disease

Inherited retinal diseases are the most common cause of vision loss among the working population in Western countries. It is estimated that ~1 of the people worldwide suffer from vision loss due to inherited retinal diseases. The severity of these diseases varies from partial vision loss to total blindness, and at the moment no effective cure exists. To date, nearly 200 mapped loci, including 140 cloned genes for inherited retinal diseases have been identified. By a rough estimation 50% of the retinal dystrophy genes still await discovery. In this thesis we aimed to study the genetic background of two inherited retinal diseases, X-linked cone-rod dystrophy and Åland Island eye disease. X-linked cone-rod dystrophy (CORDX) is characterized by progressive loss of visual function in school age or early adulthood. Affected males show reduced visual acuity, photophobia, myopia, color vision defects, central scotomas, and variable changes in fundus. The disease is genetically heterogeneous and two disease loci, CORDX1 and CORDX2, were known prior to the present thesis work. CORDX1, located on Xp21.1-11.4, is caused by mutations in the RPGR gene. CORDX2 is located on Xq27-28 but the causative gene is still unknown. Åland Island eye disease (AIED), originally described in a family living in Åland Islands, is a congenital retinal disease characterized by decreased visual acuity, fundus hypopigmentation, nystagmus, astigmatism, red color vision defect, myopia, and defective night vision. AIED shares similarities with another retinal disease, congenital stationary night blindness (CSNB2). Mutations in the L-type calcium channel α1F-subunit gene, CACNA1F, are known to cause CSNB2, as well as AIED-like disease. The disease locus of the original AIED family maps to the same genetic interval as the CACNA1F gene, but efforts to reveal CACNA1F mutations in patients of the original AIED family have been unsuccessful. The specific aims of this study were to map the disease gene in a large Finnish family with X-linked cone-rod dystrophy and to identify the disease-causing genes in the patients of the Finnish cone-rod dystrophy family and the original AIED family. With the help of linkage and haplotype analyses, we could localize the disease gene of the Finnish cone-rod dystrophy family to the Xp11.4-Xq13.1 region, and thus establish a new genetic X-linked cone-rod dystrophy locus, CORDX3. Mutation analyses of candidate genes revealed three novel CACNA1F gene mutations: IVS28-1 GCGTC>TGG in CORDX3 patients, a 425 bp deletion, comprising exon 30 and flanking intronic regions in AIED patients, and IVS16+2T>C in an additional Finnish patient with a CSNB2-like phenotype. All three novel mutations altered splice sites of the CACNA1F gene, and resulted in defective pre-mRNA splicing suggesting altered or absent channel function as a disease mechanism. The analyses of CACNA1F mRNA also revealed novel alternative wt splice variants, which may enhance channel diversity or regulate the overall expression level of the channel. The results of our studies may be utilized in genetic counseling of the families, and they provide a basis for studies on the pathogenesis of these diseases. In the future, the knowledge of the genetic defects may be used in the identification of specific therapies for the patients.

Corneal recovery after uncomplicated and complicated PRK and LASIK

Refractive errors, especially myopia, seem to increase worldwide. Concurrently, the number of surgical refractive corrections has increased rapidly, with several million procedures performed annually. However, excimer laser surgery was introduced after a limited number of studies done with animals and to date there still are only few long-term follow-up studies of the results. The present thesis aims to evaluate the safety and functional outcome of, as well as to quantify the cellular changes and remodelling in the human cornea after, photorefractive keratectomy (PRK) and laser assisted in situ keratomileusis (LASIK). These procedures are the two most common laser surgical refractive methods. In Study I, myopic ophthalmic residents at Helsinki University Eye Hospital underwent a refractive correction by PRK. Five patients were followed up for 6 months to assess their subjective experience in hospital work and their performance in car driving simulator and in other visuomotor functions. Corneal morphological changes were assessed by in vivo confocal microscopy (ivCM). Study II comprised 14 patients who had undergone a PRK operation in 1993-1994. Visual acuity was examined and ivCM examinations performed 5 years postoperatively. In Study III 15 patients received LASIK refractive correction for moderate to high myopia (-6 - -12 D). Their corneal recovery was followed by ivCM for 2 years. Diffuse lamellar keratitis (DLK) is a common but variable complication of LASIK. Yet, its aetiology remains unknown. In Study IV we examined six patients who had developed DLK as a consequence of formation of an intraoperative or post-LASIK epithelial defect, to assess the corneal and conjunctival inflammatory reaction. In the whole series, the mean refractive correction was -6.46 diopters. The best spectacle corrected visual acuity (BSCVA) improved in 30 % of patients, whereas in four patients BSCVA decreased slightly. The mean achieved refraction was 0.35 D undercorrected. After PRK, the stromal scar formation was highest at 2 to 3 months postoperatively and subsequently decreased. At 5 years increased reflectivity in the subepithelial stroma was observed in all patients. Interestingly, no Bowman s layer was detected in any patient. Subbasal nerve fiber bundle(snfb) regeneration could be observed already at 2 months in 2 patients after PRK. After 5 years, all corneas presented with snfb, the density of which, however, was still lower than in control corneas. LASIK induced a hypocellular area on both sides of the flap interface. A decrease of the most anterior keratocyte density was also observed. In the corneas that developed DLK, inflammatory cell-type objects were present in the flap interface in half of the patients. The other patients presented only with keratocyte activation and highly reflective extracellular matrix. These changes resolved completely with medication and time. Snfb regeneration was first detected at one month post-LASIK, but still after two years the density of snfb, however, was only 64 % of the preoperative values. The performance of ophthalmological examinations and microsurgery without spectacles was easier postoperatively, which was appreciated by the residents. Both PRK and LASIK showed moderate to good accuracy and high safety. In terms of visual perception and subjective evaluation, few patients stated any complaints in the whole series of studies. Instead, the majority of patients experienced a marked improvement in everyday life and work performance. PRK and LASIK have shown similar results, with good long term morphological healing. It seems evident that, even without the benefit of over-20-year follow-up results, these procedures are sufficiently safe and accurate for refractive corrections and corneal reshaping.

Postoperative Volume Therapy in Cardiac Surgery : Effects on Hemostatic and Circulatory Variables

Background: Patients may need massive volume-replacement therapy after cardiac surgery because of large fluid transfer perioperatively, and the use of cardiopulmonary bypass. Hemodynamic stability is better maintained with colloids than crystalloids but colloids have more adverse effects such as coagulation disturbances and impairment of renal function than do crystalloids. The present study examined the effects of modern hydroxyethyl starch (HES) and gelatin solutions on blood coagulation and hemodynamics. The mechanism by which colloids disturb blood coagulation was investigated by thromboelastometry (TEM) after cardiac surgery and in vitro by use of experimental hemodilution. Materials and methods: Ninety patients scheduled for elective primary cardiac surgery (Studies I, II, IV, V), and twelve healthy volunteers (Study III) were included in this study. After admission to the cardiac surgical intensive care unit (ICU), patients were randomized to receive different doses of HES 130/0.4, HES 200/0.5, or 4% albumin solutions. Ringer’s acetate or albumin solutions served as controls. Coagulation was assessed by TEM, and hemodynamic measurements were based on thermodilutionally measured cardiac index (CI). Results: HES and gelatin solutions impaired whole blood coagulation similarly as measured by TEM even at a small dose of 7 mL/kg. These solutions reduced clot strength and prolonged clot formation time. These effects were more pronounced with increasing doses of colloids. Neither albumin nor Ringer’s acetate solution disturbed blood coagulation significantly. Coagulation disturbances after infusion of HES or gelatin solutions were clinically slight, and postoperative blood loss was comparable with that of Ringer’s acetate or albumin solutions. Both single and multiple doses of all the colloids increased CI postoperatively, and this effect was dose-dependent. Ringer’s acetate had no effect on CI. At a small dose (7 mL/kg), the effect of gelatin on CI was comparable with that of Ringer’s acetate and significantly less than that of HES 130/0.4 (Study V). However, when the dose was increased to 14 and 21 mL/kg, the hemodynamic effect of gelatin rose and became comparable with that of HES 130/0.4. Conclusions: After cardiac surgery, HES and gelatin solutions impaired clot strength in a dose-dependent manner. The potential mechanisms were interaction with fibrinogen and fibrin formation, resulting in decreased clot strength, and hemodilution. Although the use of HES and gelatin inhibited coagulation, postoperative bleeding on the first postoperative morning in all the study groups was similar. A single dose of HES solutions improved CI postoperatively more than did gelatin, albumin, or Ringer’s acetate. However, when administered in a repeated fashion, (cumulative dose of 14 mL/kg or more), no differences were evident between HES 130/0.4 and gelatin.

Mediastinitis after cardiac surgery

Mediastinitis as a complication after cardiac surgery is rare but disastrous increasing the hospital stay, hospital costs, morbidity and mortality. It occurs in 1-3 % of patients after median sternotomy. The purpose of this study was to find out the risk factors and also to investigate new ways to prevent mediastinitis. First, we assessed operating room air contamination monitoring by comparing the bacteriological technique with continuous particle counting in low level contamination achieved by ultra clean garment options in 66 coronary artery bypass grafting operations. Second, we examined surgical glove perforations and the changes in bacterial flora of surgeons' fingertips in 116 open-heart operations. Third, the effect of gentamicin-collagen sponge on preventing surgical site infections (SSI) was studied in randomized controlled study with 557 participants. Finally, incidence, outcome, and risk factors of mediastinitis were studied in over 10,000 patients. With the alternative garment and textile system (cotton group and clean air suit group), the air counts fell from 25 to 7 colony-forming units/m3 (P<0.01). The contamination of the sternal wound was reduced by 46% and that of the leg wound by >90%. In only 17% operations both gloves were found unpunctured. Frequency of glove perforations and bacteria counts of hands were found to increase with operation time. With local gentamicin prophylaxis slightly less SSIs (4.0 vs. 5.9%) and mediastinitis (1.1 vs. 1.9%) occurred. We identified 120/10713 cases of postoperative mediastinitis (1.1%). During the study period, the patient population grew significantly older, the proportion of women and patients with ASA score >3 increased significantly. In multivariate logistic regression analysis, the only significant predictor for mediastinitis was obesity. Continuous particle monitoring is a good intraoperative method to control the air contamination related to the theatre staff behavior during individual operation. When a glove puncture is detected, both gloves are to be changed. Before donning a new pair of gloves, the renewed disinfection of hands will help to keep their bacterial counts lower even towards the end of long operation. Gentamicin-collagen sponge may have beneficial effects on the prevention of SSI, but further research is needed. Mediastinitis is not diminishing. Larger populations at risk, for example proportions of overweight patients, reinforce the importance of surveillance and pose a challenge in focusing preventive measures.

Refractive surgery for iatrogenic and congenital anisometropia and mild visual impairment

In anisometropia, the two eyes have unequal refractive power. Anisometropia is a risk factor for amblyopia. The visual deficiencies are thought to be irreversible after the first decade of life. There is, however, accumulating evidence that neural plasticity exists also in adult brains. The aim of this study was to investigate functional outcome of excimer laser refractive surgery in adult anisometropic and visually impaired patients. Additional goal was to examine changes in the primary visual cortex (V1) using multifocal functional magnetic resonance imaging (mffMRI) after laser refractive surgery. Study I comprised of 57 anisometropic patients (anisometropia of ≥3.25 diopters) and 174 isometropic myopic subjects formed the control group. A significant improvement in best-spectacle-corrected visual acuity (BSCVA) among myopic control subjects was evident 3 months postoperatively. The improvement in BSCVA was significantly slower for anisometropic patients and the improvement appeared to persist to the end of the follow-up (24 months). In study II we found that refractive surgery may be also successfully used for iathrogenic anisometropia. In Study III we evaluated mildly visually impaired adult patients after refractive surgery. There was a statistically significant improvement in BSCVA among visually impaired patients and the difference in the mean BSCVA between visually impaired patients and isometropic myopic control subjects diminished during follow-up. Study IV was a prospective follow-up trial examining the changes in the primary visual cortex after refractive surgery. Two anisometropic patients and two isometropic myopic patients were examined with a 61-region mffMRI before refractive surgery and at three, six, nine and twelve months postoperatively. In this study, a dramatic decrease in the number of active voxels in the fovea was found among anisometropic patients. The results presented in this thesis revealed that refractive surgery may be successfully used for the treatment of anisometropic adults with both congenital and iatrogenic anisometropia and for mildly visually impaired adults. The findings in conclusion strengthen our hypothesis of plastic changes in the visual cortex of adult anisometropic and mildly visually impaired patients after refractive surgery.

Day Surgery in Finland : randomized and cross-sectional studies on treatment, quality, and outcome

The aims of this study were to describe Finnish day surgery practice at present and to evaluate quality of care by assessing postdischarge minor morbidity and quality indicators. Potential treatment options were approached by investigating the role of oral dexamethasone as a part of multimodal analgesia and the feasibility of day surgery in patients aged 65 years and older. Over a 2-month period, all patient cases at 14 Finnish day surgery or short-stay units were analyzed (Study I). Quality indicators included rates and reasons for overnight admission, readmission, reoperation, cancellations, and patient satisfaction. Recovery during the first postoperative week was assessed at two units (Study II). Altogether 2732 patients graded daily the intensity of predefined symptoms. To define risk factors of postdischarge symptoms, multinomial regression analysis was used. Sixty patients scheduled to undergo day surgery for hallux valgus were randomized to receive twice perioperatively dexamethasone 9 mg or placebo (Study III). Paracetamol 1 g was administered 3 times daily. Rescue medication (oxycodone) consumption during 0-3 postoperative days (POD), maximal pain scores and adverse effects were documented. Medically stable patients aged 65 years or older, scheduled for open inguinal hernia repair, were randomized to receive treatment either as day cases or inpatients (Study IV). Complications, unplanned admissions, healthcare visits, and patients’ acceptance of the type of care provided were assessed during 2 weeks postoperatively. In Study I, unplanned overnight admissions were reported in 5.9%, return hospital visits during PODs 1-28 in 3.7%, and readmissions in 0.7% of patients. Patient satisfaction was high. In Study II, pain was the most common symptom in adult patients (57%). Postdischarge symptoms were more frequent in adults aged < 40 years, children aged ≥ 7 years, females, and following a longer duration of surgery. In Study III, the total median (range) oxycodone consumption during the study period was 45 (0–165) mg in the dexamethasone group, compared with 78 (15–175) mg in the placebo group (P < 0.049). On PODs 0-1, patients in the dexamethasone group reported significantly lower pain scores. Following inguinal hernia repair, no significant differences in outcome measures were seen between the study groups. Patient satisfaction was equally high in day cases and inpatients (Study IV). Finnish day surgery units provide good-quality services. Minor postdischarge symptoms are common, and they are influenced by several patient-, surgery-, and anesthesia-related factors. Oral dexamethasone combined with paracetamol improves pain relief and reduces the need for oxycodone rescue medication following correction of hallux valgus. Day surgery for open inguinal hernia repair is safe and well accepted by patients aged 65 years or older and can be recommended as the primary choice of care for medically stable patients.

Surveillance of Surgical Site Infections following Major Hip and Knee Surgery in Finland

Background and aims. Since 1999, hospitals in the Finnish Hospital Infection Program (SIRO) have reported data on surgical site infections (SSI) following major hip and knee surgery. The purpose of this study was to obtain detailed information to support prevention efforts by analyzing SIRO data on SSIs, to evaluate possible factors affecting the surveillance results, and to assess the disease burden of postoperative prosthetic joint infections in Finland. Methods. Procedures under surveillance included total hip (THA) and total knee arthroplasties (TKA), and the open reduction and internal fixation (ORIF) of femur fractures. Hospitals prospectively collected data using common definitions and written protocol, and also performed postdischarge surveillance. In the validation study, a blinded retrospective chart review was performed and infection control nurses were interviewed. Patient charts of deep incisional and organ/space SSIs were reviewed, and data from three sources (SIRO, the Finnish Arthroplasty Register, and the Finnish Patient Insurance Centre) were linked for capture-recapture analyses. Results. During 1999-2002, the overall SSI rate was 3.3% after 11,812 orthopedic procedures (median length of stay, eight days). Of all SSIs, 56% were detected after discharge. The majority of deep incisional and organ/space SSIs (65/108, 60%) were detected on readmission. Positive and negative predictive values, sensitivity, and specificity for SIRO surveillance were 94% (95% CI, 89-99%), 99% (99-100%), 75% (56-93%), and 100% (97-100%), respectively. Of the 9,831 total joint replacements performed during 2001-2004, 7.2% (THA 5.2% and TKA 9.9%) of the implants were inserted in a simultaneous bilateral operation. Patients who underwent bilateral operations were younger, healthier, and more often males than those who underwent unilateral procedures. The rates of deep SSIs or mortality did not differ between bi- and uni-lateral THAs or TKAs. Four deep SSIs were reported following bilateral operations (antimicrobial prophylaxis administered 48-218 minutes before incision). In the three registers, altogether 129 prosthetic joint infections were identified after 13,482 THA and TKA during 1999-2004. After correction with the positive predictive value of SIRO (91%), a log-linear model provided an estimated overall prosthetic joint infection rate of 1.6% after THA and 1.3% after TKA. The sensitivity of the SIRO surveillance ranged from 36% to 57%. According to the estimation, nearly 200 prosthetic joint infections could occur in Finland each year (the average from 1999 to 2004) after THA and TKA. Conclusions. Postdischarge surveillance had a major impact on SSI rates after major hip and knee surgery. A minority of deep incisional and organ/space SSIs would be missed, however, if postdischarge surveillance by questionnaire was not performed. According to the validation study, most SSIs reported to SIRO were true infections. Some SSIs were missed, revealing some weakness in case finding. Variation in diagnostic practices may also affect SSI rates. No differences were found in deep SSI rates or mortality between bi- and unilateral THA and TKA. However, patient materials between these two groups differed. Bilateral operations require specific attention paid to their antimicrobial prophylaxis as well as to data management in the surveillance database. The true disease burden of prosthetic joint infections may be heavier than the rates from national nosocomial surveillance systems usually suggest.

Preoperative visual acuity of cataract patients. Repeatability of visual acuity and refractive error measurements in clinical settings

Visual acuities at the time of referral and on the day before surgery were compared in 124 patients operated on for cataract in Vaasa Central Hospital, Finland. Preoperative visual acuity and the occurrence of ocular and general disease were compared in samples of consecutive cataract extractions performed in 1982, 1985, 1990, 1995 and 2000 in two hospitals in the Vaasa region in Finland. The repeatability and standard deviation of random measurement error in visual acuity and refractive error determination in a clinical environment in cataractous, pseudophakic and healthy eyes were estimated by re-examining visual acuity and refractive error of patients referred to cataract surgery or consultation by ophthalmic professionals. Altogether 99 eyes of 99 persons (41 cataractous, 36 pseudophakic and 22 healthy eyes) with a visual acuity range of Snellen 0.3 to 1.3 (0.52 to -0.11 logMAR) were examined. During an average waiting time of 13 months, visual acuity in the study eye decreased from 0.68 logMAR to 0.96 logMAR (from 0.2 to 0.1 in Snellen decimal values). The average decrease in vision was 0.27 logMAR per year. In the fastest quartile, visual acuity change per year was 0.75 logMAR, and in the second fastest 0.29 logMAR, the third and fourth quartiles were virtually unaffected. From 1982 to 2000, the incidence of cataract surgery increased from 1.0 to 7.2 operations per 1000 inhabitants per year in the Vaasa region. The average preoperative visual acuity in the operated eye increased by 0.85 logMAR (in decimal values from 0.03to 0.2) and in the better eye 0.27 logMAR (in decimal values from 0.23 to 0.43) over this period. The proportion of patients profoundly visually handicapped (VA in the better eye <0.1) before the operation fell from 15% to 4%, and that of patients less profoundly visually handicapped (VA in the better eye 0.1 to <0.3) from 47% to 15%. The repeatability visual acuity measurement estimated as a coefficient of repeatability for all 99 eyes was ±0.18 logMAR, and the standard deviation of measurement error was 0.06 logMAR. Eyes with the lowest visual acuity (0.3-0.45) had the largest variability, the coefficient of repeatability values being ±0.24 logMAR and eyes with a visual acuity of 0.7 or better had the smallest, ±0.12 logMAR. The repeatability of refractive error measurement was studied in the same patient material as the repeatability of visual acuity. Differences between measurements 1 and 2 were calculated as three-dimensional vector values and spherical equivalents and expressed by coefficients of repeatability. Coefficients of repeatability for all eyes for vertical, torsional and horisontal vectors were ±0.74D, ±0.34D and ±0.93D, respectively, and for spherical equivalent for all eyes ±0.74D. Eyes with lower visual acuity (0.3-0.45) had larger variability in vector and spherical equivalent values (±1.14), but the difference between visual acuity groups was not statistically significant. The difference in the mean defocus equivalent between measurements 1 and 2 was, however, significantly greater in the lower visual acuity group. If a change of ±0.5D (measured in defocus equivalents) is accepted as a basis for change of spectacles for eyes with good vision, the basis for eyes in the visual acuity range of 0.3 - 0.65 would be ±1D. Differences in repeated visual acuity measurements are partly explained by errors in refractive error measurements.