Does difference in stem design affect accuracy of stem alignment in total hip arthroplasty with a CT-based navigation system?

The efficacy of a computed tomography (CT)-based navigation system to accurately position the stem for intended alignment is unclear. In addition, the influence of stem design on the accuracy of insertion is unknown. We therefore retrospectively compared the accuracy and precision for the intended alignment of two different designs of femoral stem which were implanted with or without the navigation system. Forty-nine total hip arthroplasties (THAs) using a tapered wedge stem and 91 THAs using an anatomic stem were evaluated for the navigation group. Thirty-three THAs using the tapered wedge stem and 15 THAs using the anatomic stem were controls for the non-navigation group. Differences between postoperative measurement and preoperative planning were compared among the groups. In the navigation groups, accuracy (mean absolute difference) and precision (95% limits of agreement) of stem anteversion were 4.3° and ± 10.1° in the tapered wedge stem and 3.1° and ± 6.9° in the anatomic stem. In the non-navigation groups, these were 6.0° and ± 15.2° and 4.8° and ± 12.4°, respectively. The accuracy and precision in the navigation groups were significantly superior to those in the non-navigation group, and those in the anatomic stem group were significantly superior to those in the tapered wedge group. Using the CT-based navigation system, the accuracy and precision for intended stem anteversion were improved. When compared under guidance of navigation system, the accuracy and precision for intended stem anteversion in the anatomic stem were superior to those in the tapered wedge stem.

Effect of improved navigation performance on the accuracy of implant placement in total hip arthroplasty with a CT-based navigation system.

A computed tomography (CT)-based navigation system is one of the support tools to place implant with appropriate alignment and position in total hip arthroplasty (THA). To determine whether the higher performance of the navigation would further improve the accuracy of implant placement in the clinical setting, we retrospectively compared the navigation accuracy of two different versions of a navigation system. The newer version of the navigation system had an upgraded optical sensor with superior positional accuracy. Navigation accuracy, defined as differences between postoperative measurements on CT images and intraoperative records on the navigation system, of 49 THAs performed with the newer version of the navigation system was compared with that of 49 THAs performed with the older version. With the newer version, the mean absolute accuracy (95% limits of agreement) of implant alignment was 1.2° (± 3.3°) for cup inclination, 1.0° (± 2.4°) for cup anteversion, 2.0° (± 4.9°) for stem anteversion, and 1.1° (± 2.4°) for stem valgus angle. The accuracy of the implant position was 1.5 mm (± 3.1 mm), 1.3 mm (± 3.0 mm), and 1.5 mm (± 3.1 mm) for cup x-, y-, and z-axes, respectively, 1.6 mm (± 3.2 mm), 1.4 mm (± 2.9 mm), and 1.5 mm (± 2.7 mm) for stem x-, y-, and z-axes, respectively, and 2.4 mm (± 4.5 mm) for leg length discrepancy. The values for the newer version were significantly more accurate with less variation compared to those of the older version. With upgraded navigation performance, more accurate implant placement was demonstrated in the clinical setting.

Effects of coordinate-system construction methods on postoperative computed tomography evaluation of implant orientation after total hip arthroplasty.

OBJECTIVE: In total hip arthroplasty, it is important to assess postoperative implant orientation. The computed tomography-based (CT-based) three-dimensional (3D) templating method using 3D preoperative planning software is generally recommended. In this method, postoperative implant orientation within a bony coordinate system can be measured by overlaying a 3D computerized model of the implant on a real postoperative CT image of the implant. The bony coordinate system consists of several reference points (RPs) marked on a CT image of the bone surface. Therefore, preoperative and postoperative coordinate systems do not always match. We investigated how the difference between coordinate systems constructed from RPs chosen by manual methods (M1 and M2) and those constructed by the computer matching method influences the results of measurement validation. METHODS: In M1, postoperative RPs were chosen without a specific tool in a single planning module. In M2, postoperative RPs were chosen with as little deviation as possible from preoperative RPs, verifying preoperative RPs on another monitor. RESULTS: M1 and M2 produced mean errors in acetabular cup inclination of 0.7° ± 0.5° and 0.5° ± 0.3°, respectively, and mean errors in cup anteversion of 1.3° ± 1.2° and 0.5° ± 0.4°, respectively, which were statistically significant differences. M1 and M2 produced mean errors in femoral stem anteversion of 2.4° ± 2.0° and 2.7° ± 2.1°, respectively, not a significant difference, but these errors were larger than errors in cup orientation. DISCUSSION: We recommend referring to preoperative RPs when choosing postoperative RPs. Surgeons must be aware that for evaluation of postoperative stem anteversion, manual methods may produce considerable error.

Feasibility and safety of intracoronary nicorandil infusion as a novel hyperemic agent for fractional flow reserve measurements.

Fractional flow reserve (FFR) is a useful modality to assess the functional significance of coronary stenoses. Although adenosine triphosphate (ATP) is generally used as the hyperemic stimulus, we sometimes encounter adverse events like hypotension during FFR measurement. Nicorandil, an ATP-sensitive potassium channel opener, recognized as an epicardial and resistance vessel dilator, has not been fully evaluated as a possible alternative hyperemic agent. The aim of this study was to evaluate the feasibility and safety of intracoronary nicorandil infusion compared to intravenous ATP for FFR measurement in patients with coronary artery disease. A total of 102 patients with 124 intermediate lesions (diameter stenosis >40 and <70% by visual assessment) were enrolled. All vessels underwent FFR measurements with both ATP (150 µg/kg/min) and nicorandil (2.0 mg) stimulus. FFR, hemodynamic values, and periprocedural adverse events between the two groups were evaluated. A strong correlation was observed between FFR with ATP and FFR with nicorandil (r = 0.954, p < 0.001). The agreement between the two sets of measurements was also high, with a mean difference of 0.01 ± 0.03. The mean aortic pressure drop during pharmacological stimulus was significantly larger with ATP compared to nicorandil (9.6 ± 9.6 vs. 5.5 ± 5.8 mmHg, p < 0.001). During FFR measurement, transient atrioventricular block was frequently observed with ATP compared to nicorandil (4.0 vs. 0%, p = 0.024). This study suggests that intracoronary nicorandil infusion is associated with clinical utility and safety compared to ATP as an alternative hyperemic agent for FFR measurement.

Risk of edge-loading and prosthesis impingement due to posterior pelvic tilting after total hip arthroplasty.

BACKGROUND: Proper implant orientation is essential for avoiding edge-loading and prosthesis impingement in total hip arthroplasty. Although cup orientation is affected by a change in pelvic tilt after surgery, it has been unclear whether surgeons can prevent impingement and edge-loading by proper positioning by taking into account any change in pelvic alignment associated with alteration of hip range of motion. METHODS: We simulated implant orientation without edge-loading and prosthesis impingement, even with a change in pelvic tilt and associated change in hip range of motion after surgery, by collision detection using implant models created with computer-aided design. FINDINGS: If posterior pelvic tilting with a corresponding hyperextension change in hip range of motion after surgery remains within 10°, as occurs in 90% of cases, surgeons can avoid edge-loading and impingement by correctly orienting the implant, even when using a conventional prosthesis. However, if a 20° change occurs after surgery, it may be difficult to avoid those risks. INTERPRETATION: Although edge-loading and impingement can be prevented by performing appropriate surgery in most cases, even when taking into account postoperative changes in pelvic tilt, it may also be important to pay attention to spinal conditions to ensure that pelvic tilting is not extreme because of increasing kyphosis.

Clustering of metabolic syndrome components attenuates coronary plaque regression during intensive statin therapy in patients with acute coronary syndrome: the JAPAN-ACS subanalysis study.

BACKGROUND: The JAPAN-ACS (Japan Assessment of Pitavastatin and Atorvastatin in Acute Coronary Syndrome) trial showed that intensive statin therapy could induce significant coronary plaque regression in acute coronary syndrome (ACS). We evaluated the impact of metabolic syndrome (MetS) and its components on coronary plaque regression in the JAPAN-ACS patients. METHODS AND RESULTS: Serial intravascular ultrasound measurements over 8-12 months were performed in 242 ACS patients receiving pitavastatin or atorvastatin. Patients were divided into groups according to the presence of MetS or the number of MetS components. Although the percent change in plaque volume (%PV) was not significantly different between the MetS (n=119) and non-MetS (n=123) groups (P=0.50), it was significantly associated with an increasing number of MetS components (component 0: -24.0%, n=7; components 1: -20.8%, n=31; components 2: -16.1%, n=69; components 3: -18.7%, n=83; components 4: -13.5%, n=52; P=0.037 for trend). The percent change in body mass index (%BMI) significantly correlated with %PV (r=0.15, P=0.021), especially in the MetS components 4 group (r=0.35, P=0.017). In addition, %BMI was an independent predictor of plaque regression after adjustment for the changes of low- and high-density lipoprotein cholesterol, triglycerides and HbA(1c). CONCLUSIONS: The clustering of MetS components, but not the presence of MetS itself, could attenuate coronary plaque regression during intensive statin therapy in ACS patients. Therefore, to achieve a greater degree of plaque regression, it is necessary to treat to each MetS component and use lifestyle modification.

Distributional impact of brain microbleeds on global cognitive function in adults without neurological disorder.

BACKGROUND AND PURPOSE: Brain microbleeds (MBs) are considered to be associated with cognitive decline and can be pathologically and topographically classified as cerebral amyloid angiopathy-related (located in lobar regions) and hypertensive microangiopathy-related (located in deep regions). We examined whether different effects on global cognitive function might be seen with different distributions of MBs. METHODS: A total of 1279 adults without neurological disorders were studied prospectively. Subjects were divided into 4 groups: without-MBs group; lobar group; deep group; and with in both areas (diffuse group). The Mini-Mental State Examination was administered to determine global cognitive functions, with scores<27 regarded as subnormal. RESULTS: MBs were detected in 98 subjects (8%): 36 subjects (3%) classified as lobar group, 48 subjects (4%) as deep group, and 14 subjects (1%) as diffuse group. Subnormal scores were found in 76 subjects (5.9%), associated with age, education, hypertension, severe white matter hyperintensities, and distribution and number of MBs. In the final model of logistic regression analysis, the deep group (OR, 2.79; 95% CI, 1.14-6.79) was associated with subnormal scores, whereas the lobar group (OR, 0.77; 95% CI, 0.17-3.44) was not. Trend for the diffuse group did not reach the level of significance (OR, 5.01; 95% CI, 0.88-28.41). These trends were also seen in analysis using another cut-off point for subnormal score. Scores for total Mini-Mental State Examination and attention and calculation were significantly lower in the deep group and the diffuse groups compared with the without-MBs group. CONCLUSIONS: This Japanese cross-sectional study demonstrated that MB-related global cognitive dysfunction seems to occur based on hypertensive pathogenesis rather than on cerebral amyloid angiopathy.

Clinical characteristics by topographical distribution of brain microbleeds, with a particular emphasis on diffuse microbleeds.

From the perspective of the underlying pathogenesis of primary intracerebral hemorrhage (pICH), the topographical distribution of brain microbleeds (MBs) is divided into the lobar area and the deep brain or infratentorial areas. We investigated clinical features, including ambulatory blood pressure (ABP), of patients with MBs distributed in both areas (diffuse MBs). A total of 124 patients with first-ever acute stroke were enrolled prospectively. Gradient-echo T2∗-weighted magnetic resonance imaging (MRI) was performed using a 1.5-T scanner. Patients were classified into 4 groups: MBs-negative group (n=68), those with MBs in lobar areas (lobar group; n=6), those with MBs in deep or infratentorial areas (deep or infratentorial group; n=31), and those with MBs in both areas (diffuse group; n=19). The admission casual BP (CBP) was recorded in all patients, and ABP was measured in the ischemic stroke patients. There were significant differences in the distribution of MBs (P=.004) among the 6 stroke subtypes. All stroke subtypes except transient ischemic attack had diffuse MBs; pICH had the highest prevalence of it (35%). The severity of white matter hyperintensity (WMH) differed among the 4 groups (P < .0001), with the diffuse group having the highest prevalence of early confluent (47%) and confluent types (21%). ABP and CBP were significantly higher in the deep and diffuse groups compared with the MBs-negative group, but did not differ between the lobar group and the MBs-negative group. Our data suggest that diffuse MBs are associated with hypertensive stroke, elevated BP, and severe WMH. The pathogenesis of diffuse MBs may be related to the more severe microangiopathy involved in hypertensive arteriopathy and cerebral amyloid angiopathy.

alpha Pix enhances mutant huntingtin aggregation.

Huntington's disease is caused by polyglutamine-expanded mutant huntingtin (muhtt), an aggregation-prone protein. We identified the Pak-interacting exchange factor (alpha Pix/Cool2) as a novel huntingtin (htt) interacting protein, after screening actin-cytoskeleton organization-related factors. Using immunoprecipitation experiments, we show that alpha Pix binds to both the N-terminal of wild-type htt (wthtt) and mutant htt (muthtt). Colocalization studies revealed that alpha Pix accumulates in muthtt aggregates. Deletion analysis suggested that the dbl homology (DH) and pleckstrin homology (PH) domains of alpha Pix are required for its interaction with htt. Overexpression of alpha Pix enhanced muthtt aggregation by inducing SDS-soluble muthtt-muthtt interactions. Conversely, knocking down alpha Pix attenuated muhtt aggregation. These findings suggest that alpha Pix plays an important role in muthtt aggregation.

[Case of anti P/Q type VGCC antibody positive small lung cell carcinoma that occured with subacute cerebellar degeneration, Lambert-Eaton myasthenic syndrome, and brainstem encephalitis].

A 62-year-old man was admitted to our hospital because of rapidly progressive dysarthria, truncal ataxia, and gait disturbance. High titers of the ProGRP and anti-P/Q-type VGCC antibody were detected in the serum. High accumulation of [18F] was detected at the hilus of the left lung on [18F]-FDG-PET scan. A high-frequency repetitive stimulation test of the median nerve yielded an incremental response. On the basis of these findings, a diagnosis of paraneoplastic cerebellar degeneration (PCD) and Lambert-Eaton myasthenic syndrome (LEMS) associated with small cell lung carcinoma (SCLC) was diagnosed. After intravenous immunoglobulin therapy (IVIg), methylprednisolone (m-PSL) pulse therapy, and other multidisciplinary concurrent treatments, a partial regression of the SCLC and a significant improvement in neurological symptoms were observed. However, ataxia relapsed and brainstem encephalitis developed 6 months later. A marginal improvement in neurological symptoms was observed with IVIg, m-PSL pulse therapy, and intravenous cyclophosphamide pulse therapy (IVCY). SCLC also recurred later. We hypothesized that VGCC of the brainstem was damaged by anti-P/Q-type VGCC antibody.

Incidence and clinical significances of human T-cell lymphotropic virus type I-associated myelopathy with T2 hyperintensity on spinal magnetic resonance images.

OBJECTIVE: To clarify the incidence and clinical significance of HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) showing T2 hyperintensity in the spinal cord on magnetic resonance images (MRI). PATIENTS AND METHODS: We reviewed the spinal cord MRI of 38 HAM/TSP patients and analyzed them in relation to clinical and laboratory findings. Analyzed data were: age at onset, disease duration, disability status, responsiveness to interferon therapy, brain abnormalities on MRI, serum anti-HTLV-I titers, and cerebrospinal fluid (CSF) findings. RESULTS: MRI findings of the spinal cord were classified into 3 types, "normal" (n=22, 57.9%), "atrophy" (n=13, 34.2%) and "T2-hyperintensity" (n=3, 7.9%). Patients in the normal and atrophy types showed slowly progressive paraparesis. Significant differences were not found between the normal and atrophy types in any clinical or laboratory data, including disease duration, disability status and responsiveness to interferon-alpha therapy. Meanwhile, all patients showing T2-hyperintensity had severe paraparesis of a rapid progressive nature, with CSF IgG elevation. CONCLUSION: HAM/TSP with T2-hyperintensity on spinal MRI shows a rapid progressive clinical course with severe motor impairment. The incidence of this malignant form of HAM/TSP is estimated to be around 7.9%.

Brain microbleeds and global cognitive function in adults without neurological disorder.

BACKGROUND AND PURPOSE: Increasing attention has been paid to associations between cognitive dysfunction and brain microbleeds (MBs). Because all previous studies have investigated patients with neurological disorders, we examined subjects without neurological disorder in order to clarify pathogenic relationships. METHODS: A total of 518 consecutive adults without neurological disorder who had undergone health-screening tests of the brain were studied prospectively. Gradient-echo T2*-weighted MRI using a 1.5-T system was used to detect MBs. The Mini-Mental State Examination (MMSE) was administered to determine cognitive functions. MMSE scores <27 or >1.5 SDs below the age-related mean were regarded as subnormal. RESULTS: MBs were found in 35 subjects (6.8%). MMSE score <27 was found in 25 subjects (4.8%), with MMSE score >1.5 SDs below the age-related mean in 34 subjects (6.6%). Univariate analysis showed presence and number of MBs, short duration of education, and severe white matter hyperintensities as significantly associated with subnormal scores. In logistic regression analysis, presence of MBs (odds ratio [OR], 5.44; 95% CI, 1.83 to 16.19) and number of MBs (OR, 1.32; 95% CI, 1.04 to 1.68) still displayed significant associations with MMSE score <27. Logistic regression analysis revealed a significant relationship between presence (OR, 3.93; 95% CI, 1.44 to 10.74) and number (OR, 1.26; 95% CI, 1.01 to 1.59) of MBs and MMSE score >1.5 SDs below the age-related mean. Among MMSE subscores, "attention and calculation" was significantly lower in MB-positive subjects (P=0.017). CONCLUSIONS: MBs appear to be primarily associated with global cognitive dysfunction.

Identification of a new homozygous frameshift insertion mutation in the SIL1 gene in 3 Japanese patients with Marinesco-Sjögren syndrome.

Marinesco-Sjögren syndrome (MSS) is an autosomal recessive multisystem disorder characterized by cerebellar ataxia, cataracts, progressive muscular weakness, and developmental and mental retardation. Recently, mutations in the SIL1 gene on chromosome 5q31 have been shown to be a cause of MSS. We sequenced the entire SIL1-coding region in 3 unrelated Japanese patients with classical MSS and identified a novel homozygous frameshift insertion mutation, 936_937insG, in exon 9 in all 3 patients.

Long-term treatment of steroid-dependent myasthenia gravis patients with low-dose tacrolimus.

OBJECTIVE: To examine the long-term effects of tacrolimus in steroid-dependent myasthenia gravis (MG) patients. PATIENTS AND METHODS: We administered tacrolimus at 3 mg/day to 10 generalized MG patients presented with clinical worsening by a reduction in dose of prednisolone. The effects of tacrolimus were assessed by using the MG activities of daily living (MG-ADL) profile and the post-intervention status criteria provided by the Myasthenia Gravis Foundation of America (PSC-MGFA). RESULTS: Seven patients were able to use tacrolimus without serious adverse effects for 1.0-5.1 years (mean 3.1 years). Further, its administration improved myasthenic symptoms to the level of pharmacologic remission or minimal manifestations of PSC-MGFA in 5 patients and made it possible to discontinue prednisolone administration in 4 of those 5. However, despite improvements caused by tacrolimus, the reduction in dose of prednisolone caused worsening of symptoms in another 2 patients. In addition, blood trough levels of tacrolimus lower than the recommended range were effective to maintain long-term improvements in 2 patients. CONCLUSIONS: Administration of tacrolimus induced long-term improvements and enabled replacement of prednisolone in patients with intractable steroid-dependent MG.

Significantly increased antibody response to heterogeneous nuclear ribonucleoproteins in cerebrospinal fluid of multiple sclerosis patients but not in patients with human T-lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis.

It has been reported that antibodies (Abs) against heterogeneous nuclear ribonucleoproteins (hnRNPs) are associated with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and multiple sclerosis (MS). However, these studies were done under nonmasked conditions. In order to determine whether Abs against hnRNPs associate with HAM/TSP and MS, the authors assayed Abs against two major hnRNPs, hnRNP A1 and A2/B1, in 105 cerebrospinal fluid (CSF) samples under fully masked conditions. Samples included 40 cases of HAM/TSP, 28 of MS, and 37 of other neurological diseases. Anti-hnRNP A1 Abs, and especially anti-hnRNP A2/B1 Abs, were found significantly more often in the CSF of MS patients than in other groups. However, there was no difference in the incidence of anti-hnRNP A1 Abs between HAM/TSP and other disease groups.

Impact of lipid-lowering therapy with pitavastatin, a new HMG-CoA reductase inhibitor, on regression of coronary atherosclerotic plaque.

BACKGROUND: Recent lipid-lowering trials have reported that statin therapy may retard progression or stimulate regression of human coronary plaque. In the present study volumetric intravascular ultrasound (IVUS) analyses were performed to investigate the effect of pitavastatin, a newly developed statin, on regression of human coronary plaque. METHODS AND RESULTS: Eighty-two patients matched for age and gender from 870 consecutive patients undergoing IVUS guided percutaneous coronary intervention were retrospectively assigned to either lipid-lowering therapy (n=41; pitavastatin 2 mg/day) or control group (n=41; diet only). Serial volumetric IVUS analyses of a matched left main coronary arterial site were performed. A significant reduction in low-density lipoprotein-cholesterol (LDL-C) level of 33.2% (p<0.001) was observed in the pitavastatin group. Plaque volume index (PVI) was significantly reduced in the pitavastatin group (10.6+/-9.4% decrease) compared with the control group (8.1+/-14.0% increase, p<0.001). There were positive correlations between the percent change in the PVI and follow-up LDL-C level (r=0.500, p<0.001) and the percent change in LDL-C level (r=0.479, p<0.001). CONCLUSION: Lipid-lowering therapy with pitavastatin induced significant coronary plaque regression, associated with a significant reduction in the LDL-C level. The percent change in the PVI showed a significant positive correlation with the percent change in LDL-C level.

[Clinical characteristics, diagnostic criteria and treatment of progressive multifocal leukoencephalopathy].

The clinical characteristics, diagnostic criteria and treatment of progressive multifocal leukoencephalopathy (PML) are reviewed. PML is characterized by rapid progression and poor outcome, and therefore requires the diagnosis and treatment as early as possible. Diffusion-weighted and diffusion tensor MRI were reported to be useful for the evaluation of disease activity of PML. The detection of JCV-DNA in the cerebrospinal fluid by PCR has replaced the brain biopsy. Highly active antiretroviral therapy has improved both the survival rate and the neurological functions in HIV-associated PML. However, the treatment for immune reconstitution inflammatory syndrome, which often deteriorates neurological functions, has never been solved.

[Usefulness of carotid ultrasonography for the early detection of moyamoya disease].

We report carotid ultrasonographic findings in moyamoya disease. A 44-year-old man was admitted to our hospital because of fever, headache and nausea. Neurological examination showed neck stiffness and Kernig's sign but he was otherwise normal. Brain computed tomography showed hemorrhage in the right thalamus and the lateral ventricle. Conventional carotid ultrasonography (CCU) detected marked narrowing of the right internal carotid artery (ICA) at the proximal portion without arteriosclerosis, which fulfilled the criteria of bottle neck sign, namely, the ratio of diameter of proximal portion of ICA to that of the distal portion of common carotid artery (CCA) was less than 0.5. Additionally, CCU as well as transoral carotid ultrasonography (TOCU) showed the diameter of the ICA to be smaller than that of the external carotid artery (ECA) (diameter reversal sign). These signs strongly suggested moyamoya disease. Cerebral angiography confirmed the occlusions of intracranial ICA and moyamoya vessels. Bottle neck sign and diameter reversal sign of the carotid artery on carotid ultrasonography are useful for the early detection of moyamoya disease.