Appropriate Surgical Timing of Salter Innominate Osteotomy for Residual Acetabular Dysplasia in Children.

BACKGROUND: Salter innominate osteotomy (SIO) provides favorable results for treating residual acetabular dysplasia in young children. In this study, we examined the midterm results of SIO according to the age at surgery to determine the optimal timing of this procedure. METHODS: We retrospectively examined 50 hips of 42 patients (8 boys and 34 girls) with acetabular dysplasia who underwent SIO and were followed up until skeletal maturity. The center-edge angle (CEA) was measured based on the anteroposterior radiographs of the hip obtained before surgery, 5 weeks after surgery, and at the latest follow-up. Severin classification was evaluated at the latest follow-up. Patients were categorized into 3 groups according to age at surgery: younger than 7 years of age (group A), 7 to 8 years of age (group B), and 9 years of age or older (group C). RESULTS: The mean preoperative CEA level of 0.9 degrees improved to 17.1 degrees postoperatively, which was increased to 28.1 degrees at the latest examination. Overall, 45 hips (90%) were classified as Severin I or II, with 96% in group A, 94% in group B, and 57% in group C. In group C, postoperative acetabular coverage was similar to that in the other groups (16.6 degrees in group A, 14.8 degrees in group B, and 18.1 degrees in group C), although the final outcome was unsatisfactory. The average improvement in CEA from postoperative to skeletal maturity was significantly smaller in group C than in the other groups (12.7 degrees in group A, 11.3 degrees in group B, and 3.0 degrees in group C). CONCLUSIONS: SIO showed favorable outcomes with satisfactory acetabular coverage at skeletal maturity. However, satisfactory acetabular coverage could not be obtained in some older patients because of limited postoperative remodeling capacity and smaller secondary improvement of CEA. We recommend that SIO should be performed in patients aged 8 years or younger. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Sagittal plane deformity after temporary epiphysiodesis of the distal femur for correcting limb length discrepancy.

BACKGROUND: Outcome of the temporary epiphysiodesis procedure for limb length discrepancy (LLD) is commonly evaluated in the coronal plane. The purpose of this study was to investigate implant position and complications of the distal femur and patella in the sagittal plane after the temporary epiphysiodesis. METHODS: We retrospectively reviewed 27 patients with LLD who underwent temporary epiphysiodesis of the distal femur using staples (11 patients) or eight-plates (16 patients) between 2007 and 2015. The mean age was 9.7 years (range, 6.3-13.8) at the time of epiphysiodesis. The implants were removed after a mean period of 2.6 years (range, 0.8-4.8) from the epiphysiodesis. Correction amount of LLD was measured on anteroposterior long leg standing radiographs. Implant position, extension deformity of the distal femur (>5° from epiphysiodesis to removal of implant) and patella baja (the epiphyseal line midpoint method < 1.0) were evaluated using lateral knee radiographs. RESULTS: The average correction amount of LLD was 17.4 mm (range, 2-34). The average implant position was 43.1% (range, 35-55) from the anterior edge of the distal femoral epiphysis. At removal surgery, 16 patients (59%) had extension deformity of the distal femur and 14 patients (52%) showed patella baja. There were significant correlations between implant position and extension deformity (r = -0.51, p < 0.01) and as well as between correction amount of LLD and patella baja (r = -0.64, p < 0.01). CONCLUSION: After temporary epiphysiodesis for the treatment of LLD, extension deformity of the distal femur and patella baja occurred frequently. Anterior placement of the implants is associated with extension deformity of the distal femur. The implant should be placed in the center of distal femoral physis, not the center of femoral shaft. Excessive correction of LLD should be avoided due to a risk of patella baja.

The epidemiology of developmental dysplasia of the hip in Japan: Findings from a nationwide multi-center survey.

BACKGROUND: It has been reported that the national incidence of developmental dysplasia of the hip (DDH) has decreased in Japan. This is because of prevention activities after birth since around 1970. However, cases of late-diagnosed DDH have still been noted in some children's hospitals. There has been no recent survey of DDH in Japan. The purpose of this study was to investigate the current epidemiology of DDH using a comprehensive nationwide survey. METHODS: A questionnaire was sent to orthopedic surgeons in 1987 facilities nationwide, who were asked to complete and return a survey card on each DDH patient treated between April 2011 and March 2013. RESULTS: A total of 783 (39%) facilities completed and returned the card. Of these, 79% reported no cases of DDH-related dislocation over the 2-year period, while the remaining facilities reported 1295 cases. The characteristics of children diagnosed with DDH-related dislocation were as follows: girls (89%), left side involvement (69%), bilateral involvement (4%), positive family history (27%), first-born (56%), and pelvic position at birth (15%). Seasonal variation showed an increase in DDH incidence among those born in the winter. Overall, 199 cases (15%) were diagnosed at >1 year of age, and these included 36 cases diagnosed very late, at >3 years of age. The majority of the 199 cases of late diagnosis had received earlier routine screening at <1 year of age. CONCLUSION: The characteristics of the children diagnosed with DDH nationwide were similar to past data from local regions. However, many children were diagnosed late (>1 year of age), particularly in the more populous regions. The findings identify a need for improved early routine screening for DDH in Japan.

Is the timing of surgery associated with avascular necrosis after unstable slipped capital femoral epiphysis? A multicenter study.

BACKGROUND: An unstable slipped capital femoral epiphysis (SCFE) is associated with a high rate of avascular necrosis (AVN). The etiology of AVN seems to be multifactorial, although it is not thoroughly known. The aims of our study were to determine the rate of AVN after an unstable SCFE and to investigate the risk factors for AVN, specifically evaluating the notion of an "unsafe window", during which medical interventions would increase the risk for AVN. METHODS: This retrospective multicenter study included 60 patients with an unstable SCFE diagnosed between 1985 and 2014. Timing of surgery was evaluated for three time periods, from acute onset of symptoms to surgery: period I, <24 h; period II, between 24 h and 7 days; and period III, >7 days. Multivariate logistic regression analysis was used to identify risk factors for AVN. RESULTS: Closed reduction and pinning was performed in 43 patients and in situ pinning in 17. Among these cases, 16 patients (27%) developed AVN. The rate of AVN was significantly higher in patients treated by closed reduction and pinning (15/43, 35%) than in those treated by in situ pinning (1/17, 5.9%) (p = 0.022). In patients treated by closed reduction and pinning, the incidence of AVN was 2/11 (18%) in period I, 10/13 (77%) in period II and 3/15 (20%) in period III, showing the significantly higher rate in period II (p = 0.002). The surgery provided in period II was identified as an independent risk factor for the development of AVN. CONCLUSIONS: Our rate of AVN was 27% using two classical treatment methods. Time-to-surgery, between 24 h and 7 days, was independently associated with AVN, supporting the possible existence of an "unsafe window" in patients with unstable SCFE treated by closed reduction and pinning.

The Pavlik harness in the treatment of developmentally dislocated hips: results of Japanese multicenter studies in 1994 and 2008.

BACKGROUND: It has already been more than 50 years since the Pavlik harness was introduced in Japan, and today the Pavlik harness is widely recognized as the standard initial treatment modality for developmental dysplasia of the hip. We performed a multicenter nationwide questionnaire study concerning the results of Pavlik harness treatment twice in 1994 and 2008. METHODS: In 1994 and in 2008, we sent questionnaires to 12 institutes in Japan specializing mainly in pediatric orthopedics. We compare the results of these two studies and discuss differences in reduction rates, incidence of avascular necrosis in the femoral epiphysis and the percentage of joints with acceptable morphology (Severin grade I + II/total) at skeletal maturity. We statistically assessed these results to see whether there were changes in the treatment outcomes over this 14-year period. RESULTS: Reduction of the dislocated hips was obtained by the Pavlik harness in 80.2% (1990/2481 hips; 1994) and 81.9% (1248/1523 hips; 2008). The incidences of avascular necrosis of the proximal femoral epiphysis in the dysplastic hips were 14.3% (119/835 hips; 1994) and 11.5% (76/663 hips; 2008). The type of avascular necrosis in hips from the 2008 study was determined according to the classification of Kalamchi and MacEwen: 24/69 hips (34.8%) were classified as group I; 20/69 hips (29.0%) as group II; 11/69 hips (15.9%) as group Ill; 14/69 hips (20.3%) as group IV. The percentages of hips with acceptable outcomes at skeletal maturity discerned from Severin X-ray changes (grade I + II/total) were 72.3% (604/835 hips; 1994) and 77.7% (488/628 hips; 2008). CONCLUSION: Reduction rates and the incidence of avascular necrosis in 2008 were statistically similar to the results in 1994. The rate of acceptable outcome (Severin grade I + II/total) in 2008 was statistically higher than that of 1994.

Prognostic factors for mobility in children with osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a connective tissue disorder characterized by bone fragility. Although the disease severity is known to influence the ability to walk, little is known about how children with severe OI can achieve practical ambulation (PA). This study aimed to determine the early predictors of future mobility in children with OI. Thirty OI patients with an average age of 12.1 years were classified into the PA group (22 patients) and nonambulator group (NA group: 8 patients) on the basis of the Hoffer classification. Various clinical parameters related to mobility were compared between the PA and NA groups. Therapeutic interventions were also compared between the 2 groups. The mean age at diagnosis and initial fracture were significantly lower in the NA group than in the PA group. The height was significantly smaller in the NA group than in the PA group at all ages examined (at birth, 3 years, and 6 years). The number of patients with respiratory failure was significantly higher in the NA group than in the PA group. The age at initial corrective osteotomy of the lower extremities in the PA group was significantly lower than that in the NA group, although there was no significant difference in the disease severity in infancy between the groups. Height during infancy, age at initial fracture, and neonatal respiratory status could be prognostic factors for mobility in OI. Surgical interventions at an early age may influence walking ability in children with moderate OI.

Docking phenomenon and subsequent acetabular development after gradual reduction using overhead traction for developmental dysplasia of the hip over six months of age.

PURPOSE: This study aimed to explore the docking of the femoral head into the acetabulum after gradual reduction (GR) using traction for developmental dysplasia of the hip (DDH) and the impact on subsequent acetabular development. METHODS: A total of 40 patients with DDH (42 hips) undergoing GR using overhead traction and spica casting were retrospectively reviewed. The presence of inverted labrum and the coronal and axial femoral-acetabular distances (FADs) were compared between MRI immediately and five weeks after spica casting. The change in the acetabular index on anteroposterior pelvic radiographs were compared between hips with inverted labrum (residual group) and with normally-shaped labrum (normalized group) on follow-up MRI. RESULTS: The mean age at reduction was 13.1 months (7 to 33) and the mean follow-up duration was 7.7 years (4 to 11). The rate of inverted labrum and the FADs significantly decreased between the MRI scans (all p-values < 0.001), and previous Pavlik harness failure had no negative effect on these decreases. The acetabular indices at the ages of three and five years in the residual group were significantly larger than those in the normalized group (both p-values < 0.001). Residual acetabular dysplasia was seen in 84.2% of the residual group compared with 34.8% of the normalized group (p = 0.002). CONCLUSION: The docking phenomenon can occur during spica casting following GR using traction in children with DDH between the ages of six months and three years. The remaining inverted labrum at the cast removal may negatively affect subsequent acetabular development. LEVEL OF EVIDENCE: III - retrospective comparative study.

A new Ehlers-Danlos syndrome with craniofacial characteristics, multiple congenital contractures, progressive joint and skin laxity, and multisystem fragility-related manifestations.

We previously described two unrelated patients showing characteristic facial and skeletal features, overlapping with the kyphoscoliosis type Ehlers-Danlos syndrome (EDS) but without lysyl hydroxylase deficiency [Kosho et al. (2005) Am J Med Genet Part A 138A:282-287]. After observations of them over time and encounter with four additional unrelated patients, we have concluded that they represent a new clinically recognizable type of EDS with distinct craniofacial characteristics, multiple congenital contractures, progressive joint and skin laxity, and multisystem fragility-related manifestations. The patients exhibited strikingly similar features according to their age: craniofacial, large fontanelle, hypertelorism, short and downslanting palpebral fissures, blue sclerae, short nose with hypoplastic columella, low-set and rotated ears, high palate, long philtrum, thin vermilion of the upper lip, small mouth, and micro-retrognathia in infancy; slender and asymmetric face with protruding jaw from adolescence; skeletal, congenital contractures of fingers, wrists, and hips, and talipes equinovarus with anomalous insertions of flexor muscles; progressive joint laxity with recurrent dislocations; slender and/or cylindrical fingers and progressive talipes valgus and cavum or planus, with diaphyseal narrowing of phalanges, metacarpals, and metatarsals; pectus deformities; scoliosis or kyphoscoliosis with decreased physiological curvatures of thoracic spines and tall vertebrae; cutaneous, progressive hyperextensibility, bruisability, and fragility with atrophic scars; fine palmar creases in childhood to acrogeria-like prominent wrinkles in adulthood, recurrent subcutaneous infections with fistula formation; cardiovascular, cardiac valve abnormalities, recurrent large subcutaneous hematomas from childhood; gastrointestinal, constipation, diverticula perforation; respiratory, (hemo)pneumothorax; and ophthalmological, strabismus, glaucoma, refractive errors.

Author Correction: Transdermal delivery of nobiletin using ionic liquids.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Comparison of surgical and nonsurgical containment methods for patients with Legg-Calvé-Perthes disease of the onset ages between 6.0 and 8.0 years: Salter osteotomy versus a non-weight-bearing hip flexion-abduction brace.

Since bone healing potential decreases with age, patients with Legg-Calvé-Perthes disease should receive treatment appropriate to their age group. Nonsurgical treatment is commonly applied to patients under 6.0 years of age at the onset and surgical treatment is recommended for those over 8.0 years of age, but it remains unclear which is better for those between 6.0 and 8.0 years. The aim of this retrospective study was to compare outcomes of Salter osteotomy and a non-weight-bearing brace in this age group. Inclusion criteria were unilateral Legg-Calvé-Perthes disease patients who were 6.0-8.0 years of age at the onset, who had more than 50% femoral head involvement without hinge abduction, and who underwent either Salter osteotomy (n = 35) or a non-weight-bearing hip flexion-abduction brace (n = 18). Radiological and clinical outcomes at skeletal maturity were compared between the two groups. The mean follow-up durations were 9.4 years in the Salter osteotomy group and 10.0 years in the brace group. There was no significant difference in the modified Waldenström classification at the beginning of treatment and the Catterall and modified lateral pillar classifications evaluated at the fragmentation stage between the groups. At skeletal maturity, the Stulberg classification, the sphericity deviation score, femoral head overgrowth, and the articulo-trochanteric distance were similar between the groups, but the Salter osteotomy group showed significantly smaller lateralization of the femoral head and better acetabular shape and coverage than the brace group: femoral head lateralization (P < 0.001), acetabular depth-to-width ratio (P = 0.002), Sharp angle (P < 0.001), lateral acetabular shape (P = 0.027), acetabular head index (P < 0.001). There was no significant difference in hip pain and motion between the groups. In this age group, Salter osteotomy provides better femoral head position and acetabular shape and coverage than a non-weight-bearing brace.

A retrospective comparative study of corrective osteotomy for tibial deformities with the multiaxial correction fixator and the circular fixator.

PURPOSE: A multiaxial correction (MAC) fixator is a monolateral type of fixator that can correct multi-planer deformities. The purpose of this study is to compare the clinical outcome of correction for tibial deformities with the MAC fixator and the circular external fixators. METHODS: We retrospectively reviewed consecutive patients reconstructed with the MAC fixator (MAC group) or circular external fixators (Ring group) due to the congenital diseases or residual conditions after treatment of trauma, infection, tumor, or limb lengthening between 2003 and 2016. RESULTS: The 30 patients who had angular tibial deformity were included. In patients with tibia vara or lateral bowing, the average pre-operative mechanical medial proximal tibial angle (mMPTA) of the MAC group and the Ring group was significantly increased to 86.9 ± 3.5° in the MAC group and 88.0 ± 3.6° in the Ring group postoperatively. Medial bowing was also successfully corrected in both groups. Regarding the sagittal alignment, post-operative anatomical posterior proximal tibial angle (aPPTA) of the MAC group was deteriorated after coronal correction. The operative time was significantly shorter in the MAC group than the Ring group (p < 0.05). CONCLUSION: The MAC fixator successfully corrected coronal deformities of the tibia with shorter operative time, but it has a risk of occurrence of the procurvatum deformity compared with circular external fixators. Paying attention to the sagittal alignment, the MAC fixator can be one of the treatment options for correction of the coronal tibial deformities.

Transdermal delivery of nobiletin using ionic liquids.

Nobiletin (NOB), a flavonoid, has extremely low water solubility and low oral bioavailability; however, despite these problems, various physiological effects have been investigated in vitro. In the present study, we investigated the transdermal delivery of NOB using choline and geranic acid (CAGE), which is a biocompatible material that has been reported to be a promising transdermal delivery approach. The feasibility was evaluated by a set of in vitro and in vivo tests. A solubility evaluation demonstrated that CAGE induced excellent solubility of NOB induced by multipoint hydrogen bonding between NOB and CAGE. In vitro transdermal tests using a Franz diffusion cell showed that CAGE was effective in enhancing transdermal absorption of NOB, compared to other penetration enhancers. Subsequent in vivo tests demonstrated that CAGE significantly improved area under the concentration-time curve of NOB in vivo and NOB/CAGE sample showed 20-times higher bioavailability than oral administration of NOB crystal. Furthermore, NOB/CAGE sample also showed significant drops of the blood glucose level in rats derived from hypoglycemic activity of NOB. Thus, transdermal administration of NOB using CAGE was shown to be feasible, which indicates that the use of CAGE may be adapted for other flavonoids that also show both low water solubility and low permeability.

Photocatalytic hydroxylation of aromatic ring by using water as an oxidant.

Electrophilic oxygen species photocatalytically derived from water molecules can selectively react with the aromatic ring of both benzene and its derivatives to produce the corresponding phenols and hydrogen over platinum-loaded titanium oxide when illuminated with light of appropriate wavelength in the absence of oxygen.

Percutaneous pinning after prolonged skeletal traction with the hip in a flexed position for unstable slipped capital femoral epiphysis: A case series of 11 patients.

BACKGROUND: Unstable slipped capital femoral epiphysis (SCFE) has a relatively high risk of avascular necrosis of the femoral head. Standard treatment for unstable SCFE is still controversial. We reviewed unstable SCFE case series treated with the standardized protocol, which consisted of percutaneous pinning after prolonged skeletal traction. METHODS: Our treatment regimen for unstable SCFE patients included 1 week or more of skeletal traction with the hip in a flexed position of 45 degrees, and subsequent percutaneous pinning after unintentional reduction. Eleven patients were treated in our institution and an affiliated hospital between 2003 and 2013. Sex, age at surgery, body mass index, the presence of hormonal abnormality, duration between onset and surgery, head shaft angle, posterior tilting angle, and modified Harris hip score were investigated from the medical records and radiographs. RESULTS: There were 8 male and 3 female with an average age of 11.7 years and an average body mass index of 24.5 kg/mm. No patients had hormonal abnormalities. The duration between onset and surgery ranged from 8 to 16 days. The average preoperative and postoperative head shaft angles were 126 and 141 degrees, respectively. Postoperative posterior tilting angle was averaged of 30.7 degrees, which decreased to 21.5 degrees during follow-up period. One patient showed mild avascular necrosis only confirmed by magnetic resonance imaging, but he was uneventfully treated without additional procedures. As a result, all patients had a perfect modified Harris hip score of 91 points. CONCLUSIONS: Prolonged traction with the hip in a flexed position may not only provide gradual reduction of posteriorly displaced epiphysis but also decrease intra-articular pressure before surgery. Although percutaneous pinning after unintentional reduction leaves mild displacement of the femoral epiphysis, remodeling could be expected during remaining growth period.

Clinical Results and Complications of Lower Limb Lengthening for Fibular Hemimelia: A Report of Eight Cases.

Fibular hemimelia is a rare but the most common congenital long bone deficiency, encompassing a broad range of anomalies from isolated fibular hypoplasia up to substantial femoral and tibial shortening with ankle deformity and foot deficiency. Most cases of fibular hemimelia manifest clinically significant leg length discrepancy (LLD) with time that requires adequate correction by bone lengthening for stable walking. Bone lengthening procedures, especially those for pathological bones, are sometimes associated with severe complications, such as delayed consolidation, fractures, and deformities of the lengthened bones, leading to prolonged healing time and residual LLD at skeletal maturity. The purpose of this study was to review our clinical results of lower limb lengthening for fibular hemimelia.This study included 8 Japanese patients who diagnosed with fibular hemimelia from physical and radiological findings characteristic of fibular hemimelia and underwent single or staged femoral and/or tibial lengthening during growth or after skeletal maturity. LLD, state of the lengthened callus, and bone alignment were evaluated with full-length radiographs of the lower limb. Previous interventions, associated congenital anomalies, regenerate fractures were recorded with reference to medical charts and confirmed on appropriate radiographs. Successful lengthening was defined as the healing index <50 days/cm without regenerate fractures.A significant difference was observed in age at surgery between successful and unsuccessful lengthening. The incidence of regenerate fractures was significantly correlated with callus maturity before frame removal. LLD was corrected within 11 mm, whereas mechanical axis deviated laterally.Particular attention should be paid to the status of callus maturation and the mechanical axis deviation during the treatment period in fibular hemimelia.

Highly dispersed Ce(III) species on silica and alumina as new photocatalysts for non-oxidative direct methane coupling.

Highly dispersed cerium oxide species on silica and alumina, which mainly exist as Ce(III) species, promote non-oxidative direct methane coupling photocatalytically around room temperature, while Ce(IV) species as CeO2 particles do not behave as a catalyst for this reaction.

Characterization of molecular transport in poly(dimethylsiloxane) microchannels for electrophoresis fabricated with synchrotron radiation-lithography and UV-photolithography.

In the present paper, a study was undertaken of molecular transport in ploy(dimethylsiloxane) microchannels that were fabricated by ultraviolet (UV)-photolithography and synchrotron radiation (SR)-lithography characterized and compared for microchip capillary electrophoresis by evaluating in-channel molecular dispersion. A fluorescent tag, sulforhodamine B was used as the probing molecule. It was found that microchannels made by SR-lithography fabrication were superior to those made by UV-photolithography fabrication in terms of molecular transport performance. A deep insight into surface conditions characterized by scanning electron microscopy suggested it was related to the difference in surface roughness. Chromatographic retention in electropherograms further supported such a conclusion, which depended on the phase ratio of the channel surface. The results revealed for PDMS microchannels in this work were in good agreement with the phenomenon found for glass microchannels in the literature.

SHOX nullizygosity and haploinsufficiency in a Japanese family: implication for the development of Turner skeletal features.

We report on clinical and molecular findings in a Japanese family consisting of a male infant with SHOX nullizygosity and his four family members with SHOX haploinsufficiency. The male infant had Langer mesomelic dysplasia, the prepubertal sister had idiopathic short stature phenotype with no discernible skeletal features, the father had mild Léri-Weill dyschondrosteosis (LWDC), and the mother and the maternal grandmother had moderate LWDC. The five subjects lacked clinically recognizable short metacarpals, cubitus valgus, high arched palate, short neck, and micrognathia, as well as recurrent otitis media and hearing loss. Fluorescence in situ hybridization and sequence analyses showed that the proband had a pseudoautosomal microdeletion involving SHOX and a C502T missense mutation in the homeobox domain at exon 4, and that the father was heterozygous for the SHOX deletion, and the sister, the mother, and the grandmother were heterozygous for the C502T mutation. The results, in conjunction with the previous findings, suggest that mesomelic skeletal features such as Langer mesomelic dysplasia and LWDC, which are absent or rare in Turner syndrome, are primarily caused by the SHOX dosage effect and the bone maturing effect of gonadal estrogens, whereas other skeletal features such as short metacarpals, cubitus valgus, and various craniofacial and cervical skeletal stigmata, which are common in Turner syndrome, are largely contributed by a compressive effect of distended lymphatics and lymphedema on the developing skeletal tissues.

Fine structural photoluminescence spectra of silica-supported zirconium oxide and its photoactivity in direct methane conversion.

Highly dispersed zirconium oxide species on silica exhibit fine structure in phosphorescence emission spectra showing the vibration energy of the photoactive Zr-O-Si linkage to be 955 cm-1, and the species promotes the photoinduced non-oxidative methane coupling at room temperature.

Risk factors for contraction of the anterior capsule opening after cataract surgery.

PURPOSE: To investigate the factors contributing to contraction of the anterior capsule opening (ACO) after cataract surgery in normal eyes. SETTING: Department of Ophthalmology, University of Tokyo, School of Medicine, Tokyo, and Kaiya Eye Clinic, Hamamatsu, Japan. METHODS: This study included 141 eyes of 141 patients scheduled to have cataract surgery. The area of the ACO was determined by diaphanoscopy using the EAS-1000 anterior eye segment analysis system 1 day and 9 months postoperatively, after which the percentage reduction in the ACO area was calculated. Aqueous flare intensity was measured with a laser flare-cell meter 1 week and 9 months after surgery. Multiple regression analysis was performed to determine which factors were correlated with the percentage reduction in the ACO area. Variables tested included patient age, axial length, the ACO area on the first postoperative day, and flare values 1 week and 9 months after surgery. RESULTS: Patient age (r = 0.193, P =.029) and flare intensity 9 months after surgery (r = 0.255, P =.007) were significantly correlated with the percentage reduction in the ACO area (R(2) = 0.133). The axial length, ACO area 1 day postoperatively, and flare value at 1 week were not correlated with ACO contraction. CONCLUSION: Contraction of the ACO after cataract surgery is related to instability of the blood-aqueous barrier.