Advantages of 70-kV CT Angiography for the Visualization of the Adamkiewicz Artery: Comparison with 120-kV Imaging

BACKGROUND AND PURPOSE

Preprocedural identification of the Adamkiewicz artery is crucial in patients with aortic diseases. This study aimed to compare 70-kV CTA with conventional 120-kV CTA for the identification of the Adamkiewicz artery, examining differences in radiation dose and image quality.

MATERIALS AND METHODS

We retrospectively analyzed 2 equal groups of 60 patients who had undergone 70-kV or 120-kV CTA to detect the Adamkiewicz artery before aortic repair. Size-specific dose estimate, the CT number of the aorta, and the contrast-to-noise ratio of the anterior spinal artery to the spinal cord were recorded. Furthermore, detectability of the Adamkiewicz artery was evaluated by using a 4-point continuity score (3, definite to 0, undetectable).

RESULTS

There was significantly lower radiation exposure with 70-kV CTA than 120-kV CTA (median size-specific dose estimate, 23.1 versus 61.3 mGy, respectively; P < .001). CT number and contrast-to-noise ratio were both significantly higher in the 70-kV CTA group than the 120-kV group (999.1 HU compared with 508.7 HU, and 5.6 compared with 3.4, respectively; P < .001 for both). Detectability of the Adamkiewicz artery was not impaired in the 70-kV CTA group (90.0% versus 83.3% in the 120-kV group, P = .28). Moreover, the Adamkiewicz artery was detected with greater confidence with 70-kV CTA, reflected by a significantly superior continuity score (median, 3) compared with 120-kV CTA (median, 2; P = .001).

CONCLUSIONS

Seventy-kilovolt CTA has substantial advantages for the identification of the Adamkiewicz artery before aortic repair, with a significantly lower radiation exposure and superior image quality than 120-kV CTA.

Bone-Subtracted Spinal CT Angiography Using Nonrigid Registration for Better Visualization of Arterial Feeders in Spinal Arteriovenous Fistulas

BACKGROUND AND PURPOSE

Pretreatment diagnosis for the location of shunts and arterial feeders of spinal arteriovenous fistulas is crucial. This study aimed to evaluate the utility of subtracted CT angiography imaging by using nonrigid registration (R-CTA) in patients with spinal arteriovenous fistulas compared with conventional CTA imaging.

MATERIALS AND METHODS

The records of 15 consecutive subjects (mean age, 65 years; 2 women) who had undergone CTA and digital subtraction angiography for clinically suspected spinal arteriovenous fistula were reviewed. From CTA images obtained at the arterial and late arterial phases, warped images of the late arterial phase were obtained by using nonrigid registration that was adjusted to the arterial phase images. R-CTA images were then obtained by subtracting the warped images from the arterial phase images. The accuracies of using nonrigid registration and conventional spinal CTA and the time required for detecting arterial feeders in spinal arteriovenous fistulas were analyzed for each patient with DSA results as a standard reference. The difference between R-CTA and conventional spinal CTA was assessed by the Welch test and the McNemar χ(2) test.

RESULTS

R-CTA had a higher accuracy compared with conventional spinal CTA (80% versus 47%, P = .025). The time for interpretation was reduced in R-CTA compared with conventional spinal CTA (45.1 versus 97.1 seconds, P = .002).

CONCLUSIONS

Our subtracted CTA imaging by using nonrigid registration detects feeders of spinal arteriovenous fistulas more accurately and quickly than conventional CTA.

Three-dimensional morphology and bony range of movement in hip joints in patients with hip dysplasia

To confirm whether developmental dysplasia of the hip has a risk of hip impingement, we analysed maximum ranges of movement to the point of bony impingement, and impingement location using three-dimensional (3D) surface models of the pelvis and femur in combination with 3D morphology of the hip joint using computer-assisted methods. Results of computed tomography were examined for 52 hip joints with DDH and 73 normal healthy hip joints. DDH shows larger maximum extension (p = 0.001) and internal rotation at 90° flexion (p < 0.001). Similar maximum flexion (p = 0.835) and external rotation (p = 0.713) were observed between groups, while high rates of extra-articular impingement were noticed in these directions in DDH (p < 0.001). Smaller cranial acetabular anteversion (p = 0.048), centre-edge angles (p < 0.001), a circumferentially shallower acetabulum, larger femoral neck anteversion (p < 0.001), and larger alpha angle were identified in DDH. Risk of anterior impingement in retroverted DDH hips is similar to that in retroverted normal hips in excessive adduction but minimal in less adduction. These findings might be borne in mind when considering the possibility of extra-articular posterior impingement in DDH being a source of pain, particularly for patients with a highly anteverted femoral neck.

Differences in the locations and modes of labral tearing between dysplastic hips and those with femoroacetabular impingement

We investigated differences in the location and mode of labral tears between dysplastic hips and hips with femoroacetabular impingement (FAI). We also investigated the relationship between labral tear and adjacent cartilage damage. We retrospectively studied 72 symptomatic hips (in 68 patients: 19 men and 49 women) with radiological evidence of dysplasia or FAI on high-resolution CT arthrography. The incidence and location of labral tears and modes of tear associated with the base of the labrum (Mode 1) or body of the labrum (Mode 2) were compared among FAI, mildly dysplastic and severely dysplastic hips. The locations predominantly involved with labral tears were different in FAI and mild dysplastic hips (anterior and anterosuperior zones) and in severely dysplastic hips (anterosuperior and superior zones) around the acetabulum. Significant differences were observed in the prevalence of Mode 1 versus Mode 2 tears in FAI hips (72% (n = 13) vs 28% (n = 5)) and severe dysplastic hips (25% (n = 2) vs 75% (n = 6)). The frequency of cartilage damage adjacent to Mode 1 tears was significantly higher (42% (n = 14)) than that adjacent to Mode 2 tears (14% (n = 3)).

Hip pathology is significantly related to the locations and modes of labral tears. Mode 1 tears may be a risk factor for the development of adjacent acetabular cartilage damage.

Cite this article: Bone Joint J 2013;95-B:1320–5.

Three-dimensional patterns of early acetabular cartilage damage in hip dysplasia; a high-resolutional CT arthrography study

OBJECTIVE

The purpose of this study was to examine the three-dimensional (3D) progression patterns of early acetabular cartilage damage in hip dysplasia using high-resolutional computed tomography (CT) arthrography.

DESIGN

Thirty-two dysplastic hips of 26 Japanese symptomatic females including 21 hips in pre-stage of osteoarthritis (Kellgren-Lawrence (K-L) grade 0; mean patient age, 32.0 years) and 11 hips in early stage of osteoarthritis (K-L grade 1 or 2; mean patient age, 32.8 years) were examined. Isotropic high-resolutional CT arthrography with an image resolution of 0.5 mm in any orthogonal direction was performed. A 3D acetabular cartilage model was generated and we evaluated distribution of cartilage thickness in 12 zones after dividing the weight-bearing area of the hip joint in radial and lateral/medial directions.

RESULTS

In pre-stage of osteoarthritis, significant differences in cartilage thickness were observed between the lateral and medial zones in all radial regions, most prominently in the antero-superior region. In early stage of osteoarthritis, no significant differences in cartilage thickness were observed, except in the most posterior region. The lateral-medial (LM) ratio was defined as cartilage thickness in the lateral zone divided by that in the medial zone, and hips with the LM ratio in the antero-superior region of <1.4 had significantly more extensive involvement of labral tears than hips with the LM ratio of ≥1.4.

CONCLUSIONS

In hip dysplasia, acetabular cartilage damage was probably occurred in the antero-superior lateral area. The LM ratio may be a sensitive index to quantify early cartilage damage associated with extent of labral disorders.

Anomalous enhancement in the infrared phonon intensity of a one-dimensional uneven peanut-shaped C60 polymer

A one-dimensional (1D) uneven peanut-shaped C(60) polymer formed from electron-beam (EB)-induced polymerization of C(60) molecules showed an anomalous increase in two characteristic infrared (IR) peak intensities, which are respectively due to the radial and tangential motion of the 1D polymer, when compared to the IR peaks of pristine C(60) films. This anomaly was analyzed on the basis of the vibrational van Hove singularity (VHS), using an extended thin-shell elastic model fully considering the effects of periodic radius modulation inherent to the 1D uneven peanut-shaped C(60) polymer. We succeeded in explaining the enhancement in the tangential peak intensity by VHS, whereas the origin to cause that in the radial peak intensity is still unclear.

Lung cancer associated with an azygos lobe successfully treated with video-assisted thoracoscopic surgery

Primary lung cancer associated with an azygos lobe is extremely rare. Herein, we report the case of a 64-year-old woman with lung adenocarcinoma arising in the right upper lobe with an azygos lobe. The patient underwent a right upper lobectomy and lymph node dissection with video-assisted thoracoscopic surgery. Video-assisted thoracoscopic surgery lobectomy for lung cancer of this variant has yet to be reported. We demonstrate the intraoperative findings and the resected pulmonary lobe. This is the first case of primary lung cancer associated with the azygos lobe treated by lobectomy with video-assisted thoracoscopic surgery.

Phylogenetic study of the species within the family Streptomycetaceae

Species of the genus Streptomyces, which constitute the vast majority of taxa within the family Streptomycetaceae, are a predominant component of the microbial population in soils throughout the world and have been the subject of extensive isolation and screening efforts over the years because they are a major source of commercially and medically important secondary metabolites. Taxonomic characterization of Streptomyces strains has been a challenge due to the large number of described species, greater than any other microbial genus, resulting from academic and industrial activities. The methods used for characterization have evolved through several phases over the years from those based largely on morphological observations, to subsequent classifications based on numerical taxonomic analyses of standardized sets of phenotypic characters and, most recently, to the use of molecular phylogenetic analyses of gene sequences. The present phylogenetic study examines almost all described species (615 taxa) within the family Streptomycetaceae based on 16S rRNA gene sequences and illustrates the species diversity within this family, which is observed to contain 130 statistically supported clades, as well as many unsupported and single member clusters. Many of the observed clades are consistent with earlier morphological and numerical taxonomic studies, but it is apparent that insufficient variation is present in the 16S rRNA gene sequence within the species of this family to permit bootstrap-supported resolution of relationships between many of the individual clusters.

Grafting with hydroxyapatite granules for defects of acetabular bone at revision total hip replacement

The long-term results of grafting with hydroxyapatite granules for acetabular deficiency in revision total hip replacement are not well known. We have evaluated the results of revision using a modular cup with hydroxyapatite grafting for Paprosky type 2 and 3 acetabular defects at a minimum of ten years’ follow-up. We retrospectively reviewed 49 acetabular revisions at a mean of 135 months (120 to 178). There was one type 2B, ten 2C, 28 3A and ten 3B hips. With loosening as the endpoint, the survival rate was 74.2% (95% confidence interval 58.3 to 90.1). Radiologically, four of the type 3A hips (14%) and six of the type 3B hips (60%) showed aseptic loosening with collapse of the hydroxyapatite layer, whereas no loosening occurred in type 2 hips. There was consolidation of the hydroxyapatite layer in 33 hips (66%). Loosening was detected in nine of 29 hips (31%) without cement and in one of 20 hips (5%) with cement (p = 0.03, Fisher’s exact probability test). The linear wear and annual wear rate did not correlate with loosening.

These results suggest that the long-term results of hydroxyapatite grafting with cement for type 2 and 3A hips are encouraging.

Loading and knee alignment have significant influence on cartilage MRI T2 in porcine knee joints

OBJECTIVE

Physiological magnetic resonance imaging (MRI) under loading or knee malalignment conditions has not been thoroughly investigated. We assessed the influence of static loading and knee alignment on T2 (transverse relaxation time) mapping of the knee femoral cartilage of porcine knee joints using a non-metallic pressure device.

METHODS

Ten porcine knee joints were harvested en bloc with intact capsules and surrounding muscles and imaged using a custom-made pressure device and 3.0-T MRI system. Sagittal T2 maps were obtained (1) at knee neutral alignment without external loading (no loading), (2) under mechanical compression of 140 N (neutral loading), and (3) under the same loading conditions as in (2) with the knee at 10 degrees varus alignment (varus loading). T2 values of deep, intermediate, and superficial zones of the medial and lateral femoral cartilages at the weight-bearing area were compared among these conditions using custom-made software. Cartilage contact pressure between the femoral and tibial cartilages, measured by a pressure-sensitive film, was correlated with cartilage T2 measurements.

RESULTS

In the medial cartilage, mean T2 values of the deep, intermediate, and superficial zones decreased by 1.4%, 13.0%, and 6.0% under neutral loading. They further decreased by 4.3%, 19.3%, and 17.2% under varus loading compared to no loading. In the lateral cartilage, these mean T2 values decreased by 3.9%, 7.7%, and 4.2% under neutral loading, but increased by 1.6%, 9.6%, and 7.2% under varus loading. There was a significant decrease in T2 values in the intermediate zone of the medial cartilage under both neutral and varus loading, and in the superficial zone of the medial cartilage under varus loading (P<0.05). Total contact pressure values under neutral loading and varus loading conditions significantly correlated with T2 values in the superficial and intermediate zones of the medial cartilages.

CONCLUSIONS

The response of T2 to change in static loading or alignment varied between the medial and lateral cartilages, and among the deep, intermediate, and superficial zones. These T2 changes were significantly related to the contact pressure measurements. Our results indicate that T2 mapping under loading allows non-invasive, biomechanical assessment of site-specific stress distribution in the cartilage.

A modular femoral neck and head system works well in cementless total hip replacement for patients with developmental dysplasia of the hip

We compared a modular neck system with a non-modular system in a cementless anatomical total hip replacement (THR). Each group consisted of 74 hips with developmental hip dysplasia. Both groups had the same cementless acetabular component and the same articulation, which consisted of a conventional polyethylene liner and a 28 mm alumina head. The mean follow-up was 14.5 years (13 to 15), at which point there were significant differences in the mean total Harris hip score (modular/non-modular: 98.6 (64 to 100)/93.8 (68 to 100)), the mean range of abduction (32° (15° to 40°)/28 (0° to 40°)), use of a 10° elevated liner (31%/100%), the incidence of osteolysis (27%/79.7%) and the incidence of equal leg lengths (≥ 6 mm, 92%/61%). There was no disassociation or fracture of the modular neck.

The modular system reduces the need for an elevated liner, thereby reducing the incidence of osteolysis. It gives a better range of movement and allows the surgeon to make an accurate adjustment of leg length.

[Experience of chest wall reconstruction with newly developed material]

After the chest wall resection, its reconstruction is often needed. A 45-year-old male lung adenocarcinoma patient with chest wall invasion underwent upper lobectomy of the right lung with partial resection of 4-6th ribs. The size of the removed chest wall was 11 x 6.5 cm. We reconstructed the chest wall with Bard Composix E/X Mesh. This prosthesis is consisted of a polypropylene mesh and an expanded polytetrafluoroethylene sheet This material is seems to be useful in the reconstruction of chest wall in both preventing pulmonary adhesion and enabling good wound healing.

Evaluation of cartilage matrix disorders by T2 relaxation time in patients with hip dysplasia

OBJECTIVE

Early detection of cartilage disorder in dysplastic hips is important in predicting subsequent progression of osteoarthritis and determining the appropriate timing of osteotomy surgery. We assessed the feasibility of T2 assessment using magnetic resonance (MR) imaging at 3T for evaluating early changes in the acetabular and femoral cartilages for patients with hip dysplasia.

METHODS

Sagittal T2 maps of the hip were obtained using 3T MR imaging in 10 normal volunteers (14 hips) and in 23 patients (26 hips) with hip dysplasia at pre-arthritic stage (without osteoarthritis) or early-arthritic stage (with osteoarthritis at the Kellgren-Lawrence system of grade 1 or 2). T2 values and the visual appearance of T2 mapping, including gradient T2, low T2, and high T2 patterns, were compared at the superior zones of the acetabular and femoral cartilages among the normal, pre-arthritic, and early-arthritic groups.

RESULTS

There were no significant differences in T2 values for both cartilages among the three groups. Regarding the visual appearance of T2 mapping for the acetabular cartilage, all hips in the normal group showed a gradient T2 pattern, while the pre-arthritic groups included six hips (43%) with a low T2 pattern, and the early-arthritic group showed either a low T2 pattern (33%) or a high T2 pattern (67%). The frequency of the gradient T2 pattern was significantly lower for dysplastic hips than for normal hips, in the acetabular and femoral cartilages (P<0.05).

CONCLUSIONS

This preliminary study demonstrated the clinical feasibility of T2 assessment of hip cartilage using 3T MR imaging. T2 mapping classification may enable the early detection of osteoarthritic degeneration and the detection of developmental disorders of cartilage matrix in patients with hip dysplasia.

Contrast-enhanced multi-shot echo-planar FLAIR in the depiction of metastatic tumors of the brain: comparison with contrast-enhanced spin-echo T1-weighted imaging

BACKGROUND

The usefulness of fast fluid-attenuated inversion-recovery (FLAIR) sequences after administration of contrast medium (f-FLAIR (+)) has been shown in depicting brain tumors including metastases and meningeal carcinomatosis. Contrast-enhanced multi-shot echo-planar FLAIR (Ms-EPI-FLAIR (+)), comprising combined sequences of f-FLAIR (+) and Ms-EPI, may provide the advantages of f-FLAIR (+) along with rapid acquisition.

PURPOSE

To compare Ms-EPI-FLAIR (+) with post-contrast spin-echo T1-weighted imaging (SE-T1WI (+)) in the depiction of brain metastases.

MATERIAL AND METHODS

In 14 patients with metastatic tumors of the brain, spin-echo precontrast T1-weighted imaging (SE-T1WI (-)), fast spin-echo T2-weighted imaging (FSE-T2WI), fast-FLAIR, SE-T1WI (+), and Ms-EPI-FLAIR (+) were acquired. For qualitative evaluation of SE-T1WI (+) and Ms-EPI-FLAIR (+), receiver operating characteristic (ROC) analysis was performed in two different readers. For quantitative analysis, the intensity ratios (intensity of tumor divided by intensity of peritumoral region) in SE-T1WI (+) and Ms-EPI-FLAIR (+) were compared.

RESULTS

Although pre-contrast f-FLAIR detected 84 of 106 tumors, Ms-EPI-FLAIR (+) detected 98 of 106 tumors. In the ROC analysis for observers A and B, Az values in SE-T1WI (+) did not differ from values in Ms-EPI-FLAIR (+). Quantitatively, the intensity ratio in Ms-EPI-FLAIR (+) also did not differ from that in SE-T1WI (+).

CONCLUSION

Detectability of brain metastases with Ms-EPI-FLAIR (+) is almost similar to that with SE-T1WI (+). Ms-EPI-FLAIR (+) could be an alternative to SE-T1WI (+) in the depiction of brain metastases.

Mid-term results of cementless total hip replacement using a ceramic-on-ceramic bearing with and without computer navigation

We have developed a CT-based navigation system using infrared light-emitting diode markers and an optical camera. We used this system to perform cementless total hip replacement using a ceramic-on-ceramic bearing couple in 53 patients (60 hips) between 1998 and 2001. We reviewed 52 patients (59 hips) at a mean of six years (5 to 8) postoperatively. The mid-term results of total hip replacement using navigation were compared with those of 91 patients (111 hips) who underwent this procedure using the same implants, during the same period, without navigation. There were no significant differences in age, gender, diagnosis, height, weight, body mass index, or pre-operative clinical score between the two groups. The operation time was significantly longer where navigation was used, but there was no significant difference in blood loss or navigation-related complications. With navigation, the acetabular components were placed within the safe zone defined by Lewinnek, while without, 31 of the 111 components were placed outside this zone. There was no significant difference in the Merle d'Aubigne and Postel hip score at the final follow-up. However, hips treated without navigation had a higher rate of dislocation. Revision was performed in two cases undertaken without navigation, one for aseptic acetabular loosening and one for fracture of a ceramic liner, both of which showed evidence of neck impingement on the liner. A further five cases undertaken without navigation showed erosion of the posterior aspect of the neck of the femoral component on the lateral radiographs. These seven impingement-related mechanical problems correlated with malorientation of the acetabular component. There were no such mechanical problems in the navigated group. We conclude that CT-based navigation increased the precision of orientation of the acetabular component and control of limb length in total hip replacement, without navigation-related complications. It also reduced the rate of dislocation and mechanical problems related to impingement.

Therapeutic effects of Saireito (TJ-114), a traditional Japanese herbal medicine, on postoperative edema and inflammation after total hip arthroplasty

Saireito (TJ-114) is a traditional Japanese herbal medicine that has been used for treating edema and inflammation in diseases such as nephritic disease. This study investigates the effect of TJ-114 on postoperative edema and inflammation after total hip arthroplasty (THA). Patients who underwent cementless THA were randomly divided into two groups: Group A consisted of 8 hips of 8 patients who were treated with TJ-114 at a dose of 9 g/day 2 days before surgery and for 2 weeks after surgery; Group B consisted of 9 hips of 9 patients who did not take TJ-114. Although no significant difference was observed between the two groups for lower extremity edema, it was found that swelling of the proximal leg in Group A was less than that in Group B. Furthermore, 3 weeks after surgery, every measuring point in the lower extremity showed that TJ-114 tended to decrease postoperative swelling compared to measurements of swelling of patients who did not take TJ-114. Serum C-reactive protein (CRP) levels of 6 out of 8 patients in Group A decreased and became negative 2 weeks after surgery; however, there were no patients in Group B whose CRP levels became negative after 2 weeks. In conclusion, TJ-114 is safe and useful for the prevention and early recovery of postoperative leg edema after THA with an association of rapid CRP reduction.

Disorders of acetabular labrum and articular cartilage in hip dysplasia: evaluation using isotropic high-resolutional CT arthrography with sequential radial reformation

OBJECTIVE

Acetabular labral tear may predispose to adjacent articular cartilage disorder and hip osteoarthritis in patients with hip dysplasia. We evaluated the diagnostic ability of isotropic computed tomography (CT) arthrography with radial reformation technique for detection of acetabular labral and articular cartilage disorders, and evaluate those interactions in hip dysplasia.

METHODS

Forty-one hips in 29 patients with hip dysplasia received CT arthrography with isotropic spatial resolution of 0.5mm. After processing of multiplanar radial reformation over the whole acetabular circumference, frequencies of labral tear and acetabular cartilage disorder were evaluated at six divided zones of the weight-bearing areas. Of the 41 hips, 20 hips underwent arthroscopic examinations, and sensitivity, specificity and accuracy for detecting labral tear and acetabular cartilage disorder by CT arthrography were calculated using the arthroscopic findings as the standard of reference.

RESULTS

The sensitivity, specificity and accuracy of CT arthrography were 97%/87%/92% for labral tear and 88%/82%/85% for acetabular cartilage disorder, respectively, using arthroscopic findings as the reference. The CT arthrography showed significantly higher frequency of labral and acetabular cartilage disorders at the anterior zones. Those zones with labral tear had significantly higher frequency of adjacent cartilage disorder than zones without labral tear.

CONCLUSIONS

Isotropic CT arthrography with radial reformation technique allowed simultaneous, accurate assessment of labral and cartilage disorders in the whole acetabular circumference. Our findings indicated that labral tear is closely associated with adjacent cartilage disorder in hip dysplasia.

[Completion pneumonectomy for pulmonary aspergillosis with hyper immunoglobulin-E syndrome]

A 22-year-old man was admitted to the department of pediatrics of our institute in February 2005, because of pulmonary aspergillosis. He had been diagnosed as hyper immunoglobulin-E syndrome in infancy, and repeated pulmonary infectious desease, such as pulmonary aspergillosis. He received art of right upper lobectomy by pulmonary aspergillosis at the age of 17. In February 2005, he had hemosputum and the chest X-ray showed a giant cavity with niveau in the right lung. In spite of medical treatment by antibiotics and antimycotics, the lesion rapidly increased in size. Therefore, right completion pneumonectomy and omentopexy around the bronchial stump was done. His postoperative course was uneventful.

Full suspension mountain bike improves off-road cycling performance

AIM

The purpose of the present study was to determine the effects of suspension systems on the cycling performance of cyclists during off-road bicycling.

METHODS

Eight elite male cyclists (67.8+/-5.8 ml/min/kg of (.-)VO(2max)) performed 30-minute riding tests on bicycles with 2 different suspension setups: front suspension (FS) and front and rear suspension (FRS). Heart rate, blood lactate concentration, pedaling power, cadence, cycling velocity, and completed distance during the trial were measured creatin kinase (CK), lactic dehydrogenase (LDH) and glutamic-oxaloacetic transaminase (GOT) were measured before and after the trials.

RESULTS

The average cadence during the trial was significantly higher (p<0.05) with the FRS (73.6+/-6.1 rpm) than the FS (70.2+/-6.2 rpm). Subjects rode significantly faster (p<0.05) on FRS (24.1+/-2.6 km/h) than FS bikes (22.9+/-2.4 km/h), although no significant difference was observed in pedaling power (240.7+/-26.6 W vs 242.2+/-28.8 W, FS vs FRS, respectively). Serum creatin kinase increased significantly (p<0.05) at 24 h after the trial when cyclists exercised with the FS bike.

CONCLUSIONS

We conclude that the FRS improved cycling performance over rough terrain. FRS might therefore be more suitable for cross-country mountain bike races.

Segmental high intensity on T1-weighted hepatic MR images

BACKGROUND

We investigated the diagnostic importance of segmental high-intensity (SHI) areas not corresponding to mass lesions on T1-weighted magnetic resonance (MR) images.

METHODS

We conducted a retrospective investigation of hepatic MR images obtained from 634 patients during a 4-year period at our institution. Images were compared with findings reported in the patients' medical records. There were 16 patients (2.5%) with SHI areas not corresponding to a mass lesion. We compared MR images with plain computed tomographic (CT) scans (n = 16), angiograms (n = 12), and histologic findings (n = 10).

RESULTS

The segments with intrahepatic bile duct dilatation showed hyperintensity on T1-weighted images. In six of 16 patients, the biliary duct was more dilated in the area of hyperintensity than in areas without hyperintensity. The SHI areas appeared as areas of low attenuation (n = 13), high attenuation (n = 1), or isoattenuation (n = 2) on plain CT scans. Histologically, these areas showed ductular proliferation and deposition of bile pigment within the hepatocytes.

CONCLUSION

Segmental areas of increased signal intensity on T1-weighted images were probably due to intrahepatic cholestasis.

Analysis of a retrieved UHMWPE acetabular cup crosslinked in air with 1000 kGy of gamma radiation

The oxidation and degradation that accompany high dose gamma irradiation in air for crosslinking and sterilization are important because they could affect the clinical performance of polyethylene total joint implants. We report a clinical case of a 1000 kGy gamma-irradiated, highly crosslinked ultra-high molecular weight polyethylene acetabular cup retrieved 24 years postoperatively. Performance evaluations included absorbed radiation dose, total wear penetration, average wear rate, crystallinity, oxidation, and equibiaxial tensile properties. A retrieved acetabular cup of the same grade of polyethylene but gamma-sterilized using a conventional dose was used as control. The highly crosslinked and control cups took in about 1300 and 30 kGy of radiation, respectively, as measured using a trans-vinylene index. Direct dimensional measurements revealed average wear rates of the highly crosslinked and control cups were 0.04 and 0.06 mm/year, respectively. The oxidation index of the highly crosslinked cup was very high (0.679), but equivalent to that of a 1000 kGy irradiated reference cup. The retrieved highly crosslinked cup showed much higher equibiaxial ultimate tensile strength than the retrieved control cup. Based on these observations, the increased wear resistance and equibiaxial tensile properties that resulted from extensive crosslinking in the presence of air were partially offset by the adverse effects caused by immediate oxidation during the process.

Preservation of the bone mineral density of the femur after surface replacement of the hip

We investigated the effect of the Birmingham hip resurfacing (BHR) arthroplasty on the bone mineral density (BMD) of the femur. A comparative study was carried out on 26 hips in 25 patients. Group A consisted of 13 patients (13 hips) who had undergone resurfacing hip arthroplasty with the BHR system and group B of 12 patients (13 hips) who had had cementless total hip arthroplasty with a proximal circumferential plasma-spray titanium-coated anatomic Ti6A14V stem. Patients were matched for gender, state of disease and age at the time of surgery. The periprosthetic BMD of the femur was measured using dual-energy x-ray absorptiomentry of the Gruen zones at two years in patients in groups A and B.

The median values of the BMD in zones 1 and 7 were 99% and 111%, respectively. The post-operative loss of the BMD in the proximal femur was significantly greater in group B than in group A. These findings show that the BHR system preserves the bone stock of the proximal femur after surgery.

Staple line coverage with absorbable mesh after thoracoscopic bullectomy for spontaneous pneumothorax

BACKGROUND

Thoracoscopic simple bullectomy for primary spontaneous pneumothorax (PSP) has a relatively high postoperative recurrence rate and sometimes results in postoperative air leakage. One of the reasons for postoperative recurrence is the regrowth of bullae around the staple line. Therefore, reinforcement of the visceral pleura around the staple line is a reasonable way to prevent postoperative air leaks and recurrence. This study was done to determine the efficacy in preventing postoperative air leak and recurrent pneumothorax of widely covering the staple line with absorbable mesh after thoracoscopic bullectomy.

METHODS

Wide coverage of the staple line with absorbable mesh was performed on 114 patients with PSP. These patients were retrospectively compared with 126 patients who underwent thoracoscopic simple bullectomy alone.

RESULTS

The postoperative duration of chest drainage in the coverage group (mean, 1 day; range, 0-5) was significantly shorter than that in the simple bullectomy group (mean, 3 days; range 0-20). A prolonged air leak (>7 days) occurred in six patients in the simple bullectomy group, but there were no such leaks in the coverage group. Recurrent pneumothorax occurred in three patients (2.6%) in the coverage group and 12 patients (9.5%) in the simple bullectomy group.

CONCLUSION

Wide coverage of the staple line with absorbable mesh is effective in preventing postoperative air leak and in decreasing the recurrence rates of PSP.

[Intraoperative conversion and postoperative complication of video-assisted thoracoscopic surgery lobectomy for primary lung cancer]

By 2002, we had attempted video-assisted thoracoscopic surgery (VATS) lobectomy or segmentectomy for 140 primary lung cancer cases. Four cases (2.9%) were converted to standard posterolateral thoracotomy for oncologic reasons and aortic injury, and 7 cases (5%) were converted to minithoracotomy with a 10 cm incision due to almost injuring the vascular system. Average blood loss in these cases was 379 ml, and there was no blood transfusion required. Seven of these 11 cases had true pleural symphysis in the thoracic cavity. The remaining 129 cases, consisted of 93 lobectomies and 34 segmentectomies, performed with a minithoracotomy of 5 cm using 2 ports. Average surgical duration was 227 minutes, and blood loss was 100 ml. Postoperative complication occurred in 15 patients (11.6%). Major complications included 1 broncho-pleural fistula, 1 pulmonary infarction, 1 cerebral infarction and 1 respiratory failure needed for mechanical ventilation. However, there were no hospital deaths. The mean postoperative hospital stay was 12 days. We recommend that surgeons should pay attention to hilar dissection, particularly in the presences of adhesion and carefully judge whether to convert to thoracotomy at the time of hemorrhage. The VATS procedure has a low mortality and morbidity for lung cancer, but particulaly in high risk patients, requires care and management the same as an open thoracotomy.

Comparison of fit and fill between anatomic stem and straight tapered stem using virtual implantation on the ORTHODOC workstation

The objective of this article was to determine the influence of stem design on fit and fill using the preoperative planning workstation of the ROBODOC system. Anatomic ABG and straight Osteolock femoral components were virtually implanted into 50 femora (25 from patients with developmental dysplasia of the hip (DDH), 25 morphologically normal) on the workstation display. Fit and fill, and length of the proximal posterolateral femoral cortex removed by milling (LPFCR), were measured on the cross-sectional images. Lateral curvature (alpha angle) and anteversion of the femur were evaluated. The ABG components showed significantly better fit than the Osteolock components at the levels proximal to the lesser trochanter. The Osteolock components showed significantly greater LPFCR than the ABG components, especially in the patients with DDH. The patients with DDH showed significantly greater alpha angle and femoral anteversion than those with morphologically normal femora. With the Osteolock components, the alpha angle correlated significantly with femoral anteversion and LPFCR. Use of an anatomic proximal body of the stem helped to improve the proximal canal fit. Greater LPFCR was required when a straight stem was implanted in patients with a relatively high alpha angle.

Accuracy evaluation of surface-based registration methods in a computer navigation system for hip surgery performed through a posterolateral approach

OBJECTIVE

Many computer navigation systems have recently been developed for brain surgery, and the use of such systems in orthopedic surgery is increasing. Intraoperative registration of preoperative images is one of the most important steps in controlling the overall accuracy of computer navigation systems. Various parameters, such as CT-scan slice thickness, reconstruction pitch, intraoperative data sampling area, and data sampling volume, may affect the accuracy of registration. The purpose of this study was to evaluate the effect of the aforementioned parameters on the accuracy of registration for hip surgery performed through a posterolateral approach, and to find a clinically suitable trade-off between accuracy and surgical invasiveness.

MATERIALS AND METHODS

One cadaveric pelvis and one cadaveric femur were used for this study. Four alumina ceramic balls with a diameter of 28 mm and within 1 micrometer of sphericity were attached to the pelvis, and three similar balls attached to the femur, to determine relative position. CT-scan images of the pelvis and femur were obtained with a helical scanner. Three sets of slice thickness and slice pitch were chosen for data acquisition, and two additional sets of reconstructed data were made. Bone contours were extracted by cutting out the surrounding substrate at a given CT number threshold, and surface models of the bone were made from the resultant data. The positions of the pelvis and femur were tracked by LED markers attached to the bone using an optical three-dimensional position sensor (OPTOTRAK). Registration of the computer models to the real objects was performed by measuring the position of a certain number of surface points on each object with an OPTOTRAK pen-probe.

RESULTS AND CONCLUSION

Slice thickness and reconstruction pitch affected the accuracy of registration. As the sampling area was expanded from the periarticular area to the distant peripheral area, accuracy increased slightly. Accuracy did not increase when the whole area was used, but in fact decreased, especially in the femur. The positive effect of increasing the number of sampling points was saturated at 30 points when the surface of the periarticular area was sampled. The following trade-off between accuracy and invasiveness, in terms of various parameters of preoperative and intraoperative data, is proposed as clinically optimal: perform the CT scan with 3-mm slice thickness and 1-mm reconstruction pitch, and sample the periarticular area with 30 sampling points. With these parameters, the accuracy of registration was 1.2 mm and 0.9 degrees of bias with 0.7 mm and 0.3 degrees of RMS in the pelvis, and 1.4 mm and 0.6 degrees of bias with 1.3 mm and 0.3 degrees of RMS in the femur.

Segmentation of avascular necrosis of the femoral head using 3-D MR images

Avascular necrosis of the femoral head (ANFH) is a common clinical disorder in the orthopedic field. Traditional approaches to study the extent of ANFH rely primarily on manual segmentation of clinical magnetic resonance images (MRI). However, manual segmentation is insufficient for quantitative evaluation and staging of ANFH. This paper presents a new computerized approach for segmentation of necrotic lesions of the femoral head. The segmentation method consists of several steps including histogram based thresholding, 3-D morphological operations, oblique data reconstruction, and 2-D ellipse fitting. The proposed technique is rapid and efficient. In addition, it is available as a Microsoft Windows free software package on the Internet. Feasibility of the method is demonstrated on the data sets of 30 patients (1500 MR images).

Full weight-bearing after cementless total hip arthroplasty

In a prospective study of cementless total hip arthroplasty, 19 hips in 17 patients (Group A) were allowed full weight-bearing immediately after the operation while 18 hips in 16 patients (Group B) were first allowed weight-bearing after 6 weeks. Patients were matched for sex, age at surgery, height, weight, and follow-up period and there were no significant differences in hip scores between the two groups. Rehabilitation to gain walking ability with a cane lasted 5.8 days for Group A and 44.8 days for Group B (P = 0.0001). The hospital stay after surgery was 30.1 days for Group A and 46.7 days for Group B (P = 0.006). All patients showed bone ingrowth radiographically. There were no complications in either group.

Influence of polyethylene and femoral head surface quality on wear: a retrieval study

Thirty-two polyethylene sockets and 22 femoral heads were retrieved because of aseptic loosening more than 9 years after total hip arthroplasty. The volumetric wear rates of the retrieved polyethylene sockets were significantly greater in those coupled with an alumina head (P < 0.05). The retrieved alumina heads showed significantly better surface roughness and roundness than heads of Co-Cr and of stainless steel (P < 0.05). However, no significant difference was found in polyethylene quality demonstrated as fusion defects among the three different groups. The present study suggests that maintaining better surface roughness and roundness of the femoral heads does not always result in an in vivo reduction of polyethylene wear.

Analysis of survivorship after total hip arthroplasty using a ceramic head

To determine the clinical efficacy of an alumina ceramic head, 119 cemented total hip arthroplasties in 97 patients using an alumina head coupled with ethylene oxide gas sterilized polyethylene were reviewed. Eighty-two patients (101 hips) with greater than 10 years followup were evaluated clinically and radiographically (range, 10-17.6 years), and 97 patients (119 hips) were evaluated for survivorship analysis (range, 0.6-17.6 years). The average functional hip scores according to Merle d'Aubigné and Postel improved from 8.6 preoperatively to 15.0 at the final followup, and 57 patients (64 hips) had no pain. The average polyethylene wear rate was 0.15 mm/year (range, 0.04-0.34 mm/year). Patients with polyethylene wear greater than 3 mm showed significantly higher rates of acetabular loosening. Fifteen-year survival rates (with 95% confidence intervals) with radiographic evidence of aseptic loosening as the end point were 46.8% +/- 13.4% in acetabular components and 91.9% +/- 6.6% in femoral components. Fifteen-year survival rates of hip arthroplasties with revision because of aseptic loosening as the end point were 75.3% +/- 10.2% and 97.9% +/- 3.0%, respectively. Results of the current study suggest that using an alumina head instead of a metal head may not be beneficial when coupled with ethylene oxide gas sterilized polyethylene.

The feasibility of retrograde catheterization of the right gastric artery via the left gastric artery

Retrograde catheterization of the right gastric artery was attempted in 22 patients for the purpose of proximal right gastric artery embolization. Retrograde catheterization was successfully performed in 12 of the 14 patients (86%) with smooth anastomoses. Retrograde catheterization was unsuccessful (n = 1) or time-consuming (n = 1) in two patients (14%) with smooth anastomoses. Right gastric artery embolization was successfully performed with microcoils in 13 of the patients. In all eight patients with tortuous anastomoses, catheterization was unsuccessful. Retrograde catheterization should be considered possible when preliminary angiography indicates a smooth anastomosis with the left gastric artery.

Phase transformation of a zirconia ceramic head after total hip arthroplasty

We report two cases of surface deterioration of a zirconia ceramic femoral head associated with phase transformation after total hip arthroplasty. One head was retrieved at revision due to recurrent dislocation after six years and the other because of failure of the locking mechanism of the polyethylene liner after three years. The monoclinic content of the zirconia ceramics rose from 1% to about 30% on the surface of the heads. SEM revealed numerous craters indicating extraction of the zirconia ceramics at the surface. Surface roughness increased from an initial value of 0.006 microm up to 0.12 microm. This is the first report to show that phase transformation of zirconia ceramics causes deterioration of the surface roughness of the head in vivo after total hip arthroplasty.

Phase transformation of a zirconia ceramic head after total hip arthroplasty

We report two cases of surface deterioration of a zirconia ceramic femoral head associated with phase transformation after total hip arthroplasty. One head was retrieved at revision due to recurrent dislocation after six years and the other because of failure of the locking mechanism of the polyethylene liner after three years. The monoclinic content of the zirconia ceramics rose from 1% to about 30% on the surface of the heads. SEM revealed numerous craters indicating extraction of the zirconia ceramics at the surface. Surface roughness increased from an initial value of 0.006 3m up to 0.12 3m. This is the first report to show that phase transformation of zirconia ceramics causes deterioration of the surface roughness of the head in vivo after total hip arthroplasty.

Osteoblastic response to osteoarthrosis of the hip does not predict outcome of cementless cup fixation: 79 patients followed for 5-11 years

We evaluated the influence of osteoblastic response to osteoarthrosis of the hip on the outcome of cementless acetabular cup after 91 total hip replacements in 79 patients. Of the 91 hips, 23 were atrophic, 37 normotrophic, and 31 hypertrophic, according to Bombelli's criteria. There were no clinical or radiographic differences among the three groups at the final follow-up (average 7 (5-11) years), when stable bone growth had been achieved by all of the acetabular cups in patients with the atrophic type, 35/37 of the normotrophic type, and all the hypertrophic type. Revision of the acetabular cup was performed on 1 hip of the normotrophic type, in connection with severe polyethylene liner wear and progressive osteolysis.

Glucose intolerance, plasma insulin levels, and colon adenomas in Japanese men

Hyperinsulinemia may be related to colon carcinogenesis. Several studies have suggested that diabetes mellitus is related to increased risk of colon cancer. We examined cross-sectionally the relation of fasting plasma insulin levels and glucose tolerance status to colon adenomas. In a consecutive series of 951 men undergoing total colonoscopy for a health examination at the Japan Self Defense Forces Fukuoka Hospital from April 1998 to August 1999, we identified 233 cases of colon adenomas and 497 controls with normal colonoscopy. Glucose tolerance status was determined by a 75-g oral glucose tolerance test, and subjects were classified as normal, impaired glucose tolerance (IGT) or non-insulin dependent diabetes mellitus (NIDDM). Plasma insulin levels were measured after subjects had fasted overnight. Logistic regression analysis and analysis of covariance was used to control for age and obesity. While plasma insulin levels were unrelated to colon adenomas, NIDDM was associated with a significantly increased risk of colon adenomas. There was no association between IGT and colon adenomas. NIDDM was more strongly associated with proximal colon adenomas. The findings suggest that long-term hyperinsulinemic status associated with NIDDM may increase the risk of colon adenomas, and subsequently of colon cancer.

Optimizing femoral anteversion and offset after total hip arthroplasty, using a modular femoral neck system: an experimental study

To investigate the effectiveness of a modular femoral neck system, consisting of two neutral and four types of retroverted necks for the correction of femoral anteversion and offset in total hip arthroplasty, an experimental study was carried out, using sawbones with four different angles of femoral anteversion (16 degrees, 34 degrees, 47 degrees, and 59 degrees ). With the neutral neck, reconstruction of the preoperative anteversion and offset in the normal femur was achieved. While the 15 degrees retroverted long neck was effective for the mildly or moderately anteverted femur, this retroverted neck showed insufficient correction for the severely anteverted femur. This modular neck system proved to be useful for correction of the medial component of femoral offset in femora with anteversion of less than 47 degrees. For patients with greater anteversion, a feature which is rarely seen in the clinical situation, femoral necks with a greater degree of retroversion may be useful.

Additive effects of nicorandil on coronary blood flow during continuous administration of nitroglycerin

OBJECTIVES

We examined whether patients with ischemic heart disease (IHD) should be treated with nicorandil, an adenosine triphosphate-sensitive potassium channel opener, in addition to the regular use of nitrates.

BACKGROUND

It has been reported that nicorandil possibly has additive effects on nitroglycerin (NTG) treatment for angina, but the mechanism is not clear.

METHODS

We directly measured anterograde coronary blood flow (CBF) with a Doppler guide wire to examine the effects of intravenous administration of NTG (0.3 mg) and nicorandil (6 mg) during continuous administration of NTG at a sufficient dose (25 microg/min) in subjects with normal and stenotic coronary arteries.

RESULTS

Additional systemic administration of NTG decreased anterograde CBF (normal -19.7%; stenotic -21.2%). In contrast, nicorandil increased anterograde CBF in both normal (54.6%) and stenotic (89.6%) coronary arteries, without the coronary steal phenomenon. There was a tendency toward nicorandil-dilated diameters in the patients with stenotic arteries (p = 0.06). There were no effects of additional administration on pulmonary artery wedge pressure. There was no difference in changes in heart rate and mean aortic blood pressure between NTG and nicorandil therapy.

CONCLUSIONS

These results suggest that in patients treated with nitrates, additional administration of nicorandil is more useful, in terms of increasing CBF, than additional administration of nitrates. Adjunctive use of nicorandil with nitrates may provide the further benefit of myocardial protection and may improve the prognosis of patients with IHD.

Articular cartilage abnormalities in dysplastic hips without joint space narrowing

Three-dimensional magnetic resonance imaging in the coronal and sagittal planes was performed in 25 normal hips of 16 volunteers and 70 dysplastic hips of 50 patients with clinical symptoms but without radiologic joint space narrowing. A high prevalence of cartilage abnormalities was detected, mostly located at the anterosuperior area in the hip: 31 hips (44%) in the acetabular cartilage and five hips (7%) in the femoral cartilage showed a mild to moderate defect of cartilage thickness. The presence of cartilage abnormalities had a statistically significant correlation with age of the patients and severity of hip pain. Of 31 hips with cartilage abnormalities, sagittal magnetic resonance images showed abnormalities in 30 (97%), whereas coronal magnetic resonance images revealed abnormalities only in 11 (35%). A high incidence of cartilage abnormalities in the preradiologic stage suggests the need for more sensitive modalities for early diagnosis. Magnetic resonance imaging in the sagittal plane allows detailed assessment of early cartilage abnormalities.

Bone scintigraphy for osteonecrosis of the knee in patients with non-traumatic osteonecrosis of the femoral head: comparison with magnetic resonance imaging

OBJECTIVE

To determine whether technetium bone scintigraphy (BS) is useful for screening of non-traumatic osteonecrosis of the knee (ONK), which was a major affected site, secondary to the femoral head, among multiple osteonecrosis, in patients with non-traumatic osteonecrosis of the femoral head (ONFH).

METHODS

A total of 214 knee joints in 107 patients with ONFH were evaluated by BS and a comparison made with magnetic resonance imaging (MRI). ONK was classified into five sites, including the femoral condyles (ONFC), distal femoral metaphysis (ONFM), tibial plateau (ONTP), proximal tibial metaphysis (ONTM), and patella (ONP).

RESULTS

Based on the diagnosis by MRI, ONK was detected in 103 knees of 62 patients (48%). ONFC was most common (86 knees, 40%), ONFM (15%), followed by ONTM (10%), ONP (3%), and ONTP (0.9%). Sensitivity, specificity, and accuracy of BS for ONFC detection were 63%, 71%, and 68%, respectively. When the ONFC lesions on the coronal views of MRI were large or medium sized and occupied two thirds, or the entire anteroposterior joint surface on the sagittal views, the sensitivity of BS for ONFC detection increased to 89% (34/38 knees). The sensitivity of BS for ONFM, ONTM, and ONP detection was 3%, 0%, and 0%, respectively, but these lesions showed a low likelihood of collapse.

CONCLUSION

BS is useful for screening large ONK in patients with ONFH given that 89% of patients with ONFC who had a high risk of collapse of the knee were identified.

Early MRI findings of rapidly destructive coxopathy

To diagnose rapidly destructive coxopathy (RDC) in its early stages and understand the pathomechanism of associated joint destruction, ten cases of RDC were followed by periodic MRI from onset of the disease. In the initial stage (stage 1) of RDC, when radiographs revealed slight narrowing of the joint space, a small subchondral area of low signal intensity was observed on T(1)-weighted images (T1WI) and inhomogeneous high intensity was observed on T(2)-weighted images (T2WI) in the antero-lateral portion of the femoral head. When radiographs showed obliteration of the joint space (stage 2), MRI revealed a diffuse area of low intensity on TIWI and high intensity on T2WI in the proximal femur, including the femoral neck and head, suggesting extensive bone marrow edema. The femoral head and acetabulum were aggressively destroyed (stage 3) in all cases 3 to 6 months after the diffuse abnormal pattern was observed on MRI. MRI in stage 3 cases showed low intensity areas on both T1WI and T2WI. RDC did not show the band-like pattern of low intensity on T1WI and high intensity on T2WI that typify MRI findings in cases of osteonecrosis. When joint space narrowing is observed radiographically, the diffuse abnormal pattern of low intensity on T1WI and high intensity on T2WI induced by a subchondral small lesion might be an early sign of RDC.