Clinical Features and Surgical Outcomes of Osteochondroma of the Spine.

Introduction: Spinal osteochondroma is rare. The purpose of this study is to examine the clinical characteristics and surgical treatment outcomes of 11 patients with spinal osteochondroma. Materials and methods: The study included 11 patients with spinal osteochondroma. In these patients, we examined the onset level, onset site, initial symptoms, surgical procedure, outcomes and complications. Results: Of the 11 patients, 9 presented with solitary tumours, and 2 had multiple. The mean post-operative observation period was six years and two months. The onset level was the cervical spine in eight patients, thoracic in two, and lumbar in one. The most common onset site was the posterior elements. The initial presentation was myelopathy in seven patients, radiculopathy in two, neck pain in one and feeling of mass in one. All patients underwent excision of the tumour, and depending on the tumour onset site, additional posterior or anterior decompression with or without fusion was performed. There was no recurrence in all patients. Intra-operative complications included dura tear and oesophageal injury in one patient with cervical onset, while post-operative complications included C5 palsy in one patient. Conclusions: In this study, surgical excision for osteochondroma of the spine were excellent with no recurrence of the tumour.

Clinical Features and Surgical Outcomes of Osteochondroma of the Spine

@#Introduction: Spinal osteochondroma is rare. The purpose of this study is to examine the clinical characteristics and surgical treatment outcomes of 11 patients with spinal osteochondroma. Materials and methods: The study included 11 patients with spinal osteochondroma. In these patients, we examined the onset level, onset site, initial symptoms, surgical procedure, outcomes and complications. Results: Of the 11 patients, 9 presented with solitary tumours, and 2 had multiple. The mean post-operative observation period was six years and two months. The onset level was the cervical spine in eight patients, thoracic in two, and lumbar in one. The most common onset site was the posterior elements. The initial presentation was myelopathy in seven patients, radiculopathy in two, neck pain in one and feeling of mass in one. All patients underwent excision of the tumour, and depending on the tumour onset site, additional posterior or anterior decompression with or without fusion was performed. There was no recurrence in all patients. Intra-operative complications included dura tear and oesophageal injury in one patient with cervical onset, while post-operative complications included C5 palsy in one patient. Conclusions: In this study, surgical excision for osteochondroma of the spine were excellent with no recurrence of the tumour.

Radiological study of cervical ossification of the posterior longitudinal ligament.

The rate of progression of cervical ossification of the posterior longitudinal ligament (OPLL) was radiologically studied during a 3-year period in three patient populations: (a) after laminoplasty (25 patients), (b) after laminectomy (16 patients), and (c) in patients who were managed without surgery (56 patients). There appeared to be no significant difference between these two surgical procedures in postoperative progression of OPLL. When progression of OPLL was compared between patients treated surgically and nonsurgically, posterior surgery accelerated progression of OPLL.

Doxorubicin overproduction in Streptomyces peucetius: cloning and characterization of the dnrU ketoreductase and dnrV genes and the doxA cytochrome P-450 hydroxylase gene.

Doxorubicin-overproducing strains of Streptomyces peucetius ATCC 29050 can be obtained through manipulation of the genes in the region of the doxorubicin (DXR) gene cluster that contains dpsH, the dpsG polyketide synthase gene, the putative dnrU ketoreductase gene, dnrV, and the doxA cytochrome P-450 gene. These five genes were characterized by sequence analysis, and the effects of replacing dnrU, dnrV, doxA, or dpsH with mutant alleles and of doxA overexpression on the production of the principal anthracycline metabolites of S. peucetius were studied. The exact roles of dpsH and dnrV could not be established, although dnrV is implicated in the enzymatic reactions catalyzed by DoxA, but dnrU appears to encode a ketoreductase specific for the C-13 carbonyl of daunorubicin (DNR) and DXR or their biosynthetic precursors. The highest DXR titers were obtained in a dnrX dnrU (N. Lomovskaya, Y. Doi-Katayama, S. Filippini, C. Nastro, L. Fonstein, M. Gallo, A. L. Colombo, and C. R. Hutchinson, J. Bacteriol. 180:2379-2386, 1998) double mutant and a dnrX dnrU dnrH (C. Scotti and C. R. Hutchinson, J. Bacteriol. 178:7316-7321, 1996) triple mutant. Overexpression of doxA in a doxA::aphII mutant resulted in the accumulation of DXR precursors instead of in a notable increase in DXR production. In contrast, overexpression of dnrV and doxA jointly in the dnrX dnrU double mutant or the dnrX dnrU dnrH triple mutant increased the DXR titer 36 to 86%.

Analysis of rising from a chair after total knee arthroplasty.

The relationship between the range of motion following total knee arthroplasty (TKA) and the height of chairs when rising from a seated position was analyzed. Forty-six TKA subjects were evaluated; 16 had osteoarthritis, 30 had rheumatoid arthritis. Subjects were divided into two groups based on their degree of knee flexion (average: 96.0 degrees; range: 75 degrees to 135 degrees; group 1 contained 24 subjects with < 100 degrees of flexion and group 2 contained 22 subjects with > 100 degrees of flexion) in order to evaluate the acceptable knee flexion angle required for comfortably rising from a chair. To evaluate the flexion-extension angle of the knee and hip joints, three goniometers, a large reaction force plate, and a switch sensor on the chair surface to detect the initiation of rising were used. One chair had a height equal to the subjects' lower leg length, while the height of the second chair was 120% of the subjects' lower leg length. Analysis showed that TKA patients with less knee flexion (< 100 degrees) required a high angular velocity of the hip and excessive swing velocity to lift the trunk forward than did those with a larger degree of knee flexion (> 100 degrees). We concluded that a minimum of 100 degrees of postoperative flexion is desired and that a higher chair is more suitable for TKA patients.

The function of posterior tilt of the tibial component following posterior cruciate ligament-retaining total knee arthroplasty.

To increase the range of motion in the knee, posterior cruciate ligament-retaining total knee arthroplasty (TKA), which has a roll back (RB) mechanism, is used. The roll back mechanism is the complex movement of the femoral condyles relative to the tibial plateau, which results in translation of the tibiofemoral contact point posteriorly as the knee is flexed. This study was undertaken to assess the function of the posterior cruciate ligament (PCL) and posterior tibial tilt following PCL-retaining TKA. Eleven fresh-frozen cadaveric normal lower extremity specimens (average age: 75.4 years; range: 69 to 88 years) were obtained for this study. The test was performed on a loading frame after specimen preparation. The calcaneal bone was fixed on the rigid frame. A load of 9.5 kg was applied perpendicularly by the moving frame to femoral head through four casters. PCL strain and RB were measured before and following TKA by changing the posterior tilt of tibial component and the external rotation of femoral component. PCL strain at 105 degrees flexion in the 0 degree posterior tilt group (3.3% +/- 2.4%) was decreased in the 10 degrees posterior tilt group (0.6% +/- 0.5%), and this decrease was statistically significant (p < 0.05). RB was measured as anterior-posterior translation by using an arthroscopic probe. After TKA, RB was decreased in the medial compartment but was increased in the lateral component. These different movements of the tibiofemoral contact points consequently caused rotation in the flexion position. Posterior tilt of the tibial component decreased the efficiency of the PCL's function. Retaining the PCL physically is not the same as preserving the function of the PCL because of the lack of the ACL, the change of the joint line, the differences in articular geometry, and the balance of the ligaments.

A simple method of intraoperative limb length measurement in total hip arthroplasty.

The equalization of leg-length discrepancy during total hip arthroplasty can be achieved through the use of a simple measuring device, the Calipers Dual Pin Retractor. During total hip arthroplasty a stable reference point must be established to determine leg-length changes. The Calipers Dual Pin Retractor was developed to establish a fixed point on the pelvis, which would remain constant throughout the procedure, from which the distance to the trochanteric area could be measured prior to the dislocation of the hip. This measurement is then used to aid in the proper placement of the femoral components.

Long-term follow-up review of suspension laminotomy for cervical compression myelopathy.

This study compared the long-term outcome of cervical spondylotic myelopathy (CSM) with that of the ossification of the posterior longitudinal ligament of the cervical spine (OPLL) after suspension laminotomy, which was developed in the authors' clinic. Seventy-six patients who received follow-up care for more than 5 years were available for analysis. The duration of the follow-up period averaged 97.8 months (range 61-160 months). Radiological and neurological analyses were performed in these 76 patients (50 with CSM and 26 with OPLL). There were no differences in sex, age, follow-up period, and preoperative neurological status between the two groups. In the quantitative study of the dural configuration, 43 patients (86%) with CSM and 17 patients (65.4%) with OPLL attained complete decompression 1 month after surgery. At long-term follow-up review, complete decompression was maintained in 42 patients (84%) with CSM but in only seven patients (26.9%) with OPLL. The neurological evaluation improved markedly at early follow up in both groups but declined insignificantly at the last follow-up review, particularly in the OPLL group. Of 12 patients (24%) with CSM and 10 patients (38.5%) with OPLL whose neurological recovery grades later deteriorated, four (8%) with CSM and nine (34.6%) with OPLL demonstrated reconstriction causing spinal cord compression at long-term follow-up review. For the remaining eight patients (16%) with CSM, who were older than 70 years on average at last follow-up review, no radiological explanation was found. These long-term results indicate that OPLL does not resolve as well as CSM after suspension laminotomy; they both may have late deterioration due to reconstriction that occurs occasionally in CSM and frequently in OPLL.

Bond strengths of resin to enamel and dentin treated with low-pressure air abrasion.

The effect of low-pressure (41.8 psi) air abrasion with alumina and glass beads on bonding to tooth substrates was evaluated. Tensile bond strengths of a bonding resin to air-abraded bovine enamel and dentin were measured. Scanning electron microscopy was used to observe (1) air-abraded surfaces, (2) fractured surfaces after the tensile bond test, and (3) interfaces of bonded specimens. Air abrasion with glass beads significantly decreased the bond strengths to enamel and dentin, whereas air abrasion with alumina decreased adhesion to enamel but not to dentin. The air-abraded enamel and dentin surfaces were irregularly roughened, and smear layers were created by air abrasion. Hybrid layers were observed at the interface between the bonding resin and the air-abraded dentin. The SEM photographs suggested that air abrasion may weaken the tooth surfaces, which could account for the decrease of the bond strengths.

Opacity and color changes of tooth-colored restorative materials.

Internal opacity and color changes of several esthetic direct restorative materials were determined using an accelerated test proposed by Asmussen (1981). Five chemically cured composites, seven light-cured composites, and three resin-modified glass-ionomer cements were placed in acrylic rings. After curing, they were left at 37 degrees C for 1 week before baseline measurement, and then stored in 60 degrees C distilled water up to 4 weeks. Color change was determined by a color analyzer, and contrast ratio representing opacity was calculated. All chemically cured composites tested discolored to dark yellow or dark brown after 4 weeks. Opacity decreased for two macrofilled composites. Light-cured composites discolored slightly, but their opacity change was negligible. All resin-modified glass-ionomer cements tested showed an abrupt decrease of opacity at the initial stage, with accompanying darkening of the materials. Opacity decrease was found to be a factor of discoloration for some tooth-colored restorative materials, and might be caused by a refractive index change of the matrix phase of the materials.

Morphological analysis of the cervical spinal canal, dural tube and spinal cord in normal individuals using CT myelography.

To verify the conventional concept of "developmental stenosis of the cervical spinal canal", we performed a morphological analysis of the relations of the cervical spinal canal, dural tube and spinal cord in normal individuals. The sagittal diameter, area and circularity of the three structures, and the dispersion of each parameter, were examined on axial sections of CT myelograms of 36 normal subjects. The spinal canal was narrowest at C4, followed by C5, while the spinal cord was largest at C4/5. The area and circularity of the cervical spinal cord were not significantly correlated with any parameter of the spinal canal nor with the sagittal diameter and area of the dural tube at any level examined, and the spinal cord showed less individual variation than the bony canal. Compression of the spinal cord might be expected whenever the sagittal diameter of the spinal canal is below the lower limit of normal, that is about 12 mm on plain radiographs. Thus, we concluded that the concept of "developmental stenosis of the cervical spinal canal" was reasonable and acceptable.

A-72363 A-1, A-2 and C, novel heparanase inhibitors from Streptomyces nobilis SANK 60192. I. Taxonomy of producing organism, fermentation, isolation and structure elucidation.

Novel heparanse inhibitors, A72363 A-1, A-2, and C, were isolated from the culture filtrate of Streptomyces nobilis SANK 60192 by column chromatography on various resinous adsorbents, followed by preparative anion exchange HPLC. Spectroscopic studies revealed that they are diastereomers of siastatin B, a neuraminidase inhibitor.

A-72363 A-1, A-2, and C, novel heparanase inhibitors from Streptomyces nobilis SANK 60192, II. Biological activities.

Inhibitory activities of A-72363 A-1, A-2 and C, the diastereomers of a neuraminidase inhibitor siastatin B, against various glycosidases were tested in comparison to siastatin B. Despite these compounds differing only in their configuration, each compound showed strikingly different specificities towards the various glycosidases tested. A-72363 C inhibited bovine liver beta-glucuronidase and tumor cell heparanase with IC50 values of 1.6 microM and 12 microM, respectively.

Vertebral slip in lumbar spondylolysis and spondylolisthesis. Long-term follow-up of 22 adult patients.

We studied the aetiology of vertebral slip in a long-term follow-up of 22 adult patients with isthmic spondylolysis or spondylolisthesis of L5. Of the 18 with spondylolysis without slip, 13 showed no slip after ten years, but five developed displacement of over 5%. All four patients with spondylolisthesis showed progression of the slip. We found that the vertical thickness of the transverse process of L5 was significantly greater (p < 0.01) in the 13 patients with no slip than in the other two groups. The relationship of vertebral slip to the shape of the transverse processes of L5 may be explained by differences in the bulk or physiological strength of the posterior bands of the iliolumbar ligament.

Shear and tensile bond testing for resin cement evaluation.

OBJECTIVES: The aim of this study was to compare the tensile and shear bond strengths of one experimental and four commercially available resin cements following the ISO document TR 110405 for bond measurement. METHODS: Tensile and shear bond tests were performed using bovine enamel and dentin as the tooth substrate with each of the resin cements. Resin composite rods were cemented to the prepared tooth surfaces. The bond strengths were obtained 24 h after cementation, and mode of failure was classified after fracture of the bonds, both visually and by SEM observation. RESULTS: Significant differences existed between the two bond test methods for all materials with enamel and three of the five cements when bonded to dentin. The shear test results were always the higher of the two test methods. Mode of fracture varied little for the visual classification, but the morphology from SEM observations showed considerable differences. SIGNIFICANCE: Although there are deficiencies in the current test methods these may be outweighed by substrate variables. A test model should be designed to determine which stresses, tensile or shear, are the greatest for different types of restorations. With this information, the type of test selected could provide appropriate information before clinical trials are commenced.

In vivo adhesive interface between resin and dentin.

V-shaped cervical cavities prepared in monkey teeth were restored with several dentin bonding systems, and the in vivo resin-dentin interfacial structures were observed under the scanning electron microscope using an argon-ion etching technique. The hybrid layer could be clearly observed; its depth was dependent on the conditioner/primer used and tended to be thinner at the deep part of the cavity. Resin tags were also clearly observed, and their structure at the inner part was noted to be rougher than that closer to the tubule orifices. When 37% phosphoric acid gel was used, the tags in the deeper parts of the cavity were much rougher. Hemispherical and spherical roughened structures were observed directly above the tubule orifices, which were thought to be a mixture of dentinal fluid and bonding resin that had flowed out from the tubules. The acidic primer containing maleic acid and HEMA could not remove the smear plugs, and undissolved smear particles were observed in the tubules.

Treatment and prognosis of a vertically fractured maxillary molar with widely separated segments: a case report.

This is a report of the treatment and prognosis of a maxillary second molar exhibiting a complete vertical crown-root fracture. The buccal and palatal segments were widely separated by as much as 2 mm and were immobile. To restore this tooth, it was essential to bring the segments into close apposition. This was accomplished by application of orthodontic elastics to the tooth crown in combination with a wire splint. After approximately 1 month of continuous use of the orthodontic elastics, the dislodged segments were suitably repositioned close to their original positions. The tooth was then endodontically treated and restored with a cast complete crown. The restored tooth has been functioning well, with periodic periodontal maintenance, for more than 3.5 years, indicating a promising prognosis.

Comparative SEM and TEM observations of nanoleakage within the hybrid layer.

Most adhesive interface studies have involved SEM demonstration of the penetration of adhesive resins into demineralized dentin surfaces with subsequent creation of hybrid layers. Nanoleakage is a term that describes the diffusion of small ions or molecules within the hybrid layer in the absence of gap formation. The present microscopic study examined the nanoleakage of the hybrid layer using a silver nitrate staining technique. Adhesive dentin sandwiches, which were immersed in a silver nitrate solution, were prepared for both SEM and TEM examination using both the Clearfil Liner Bond and All-Bond 2 adhesive systems. Both systems demonstrated silver accumulation within the hybrid layers. Clearfil Liner Bond System showed scattered silver particles at the bottom two-thirds of the hybrid layer by both SEM and TEM observation, whereas All-Bond 2 revealed stained fiber-like structures within the full thickness of the hybrid layer. To evaluate the quality of the hybrid layer, the utilization of tracer molecules such as silver nitrate that are detectable by both SEM and TEM is proposed. It is important to determine the location and morphology of these nanometer-sized porosities that may permit the hydrolysis of collagen fibers and degradation of adhesive monomers.

Effect of air-powder polishing on adhesion of bonding systems to tooth substrates.

OBJECTIVES: The air-powder polisher was introduced to provide a method to quickly remove stains and plaque. The purpose of this study was to evaluate what effect preparing teeth with an air-powder polisher (Air-flow 2, Shofu) has on bonding to enamel and dentin substrates. METHODS: The bonding systems used in this study were one-step etching/priming systems (KBT-5, Kanebo; and Clearfil Liner Bond II, Kuraray) and a two-step etching/priming system (Superbond D-Liner Plus, Sun Medical). Bovine enamel and dentin surfaces were prepared and finished with 600-grit silicon carbide paper. Then the surfaces were either not treated (control) or air-powder polished for 15 s. A 4-mm bonding area was demarcated, and the tooth substrates were bonded with the three bonding systems according to the manufacturers' instructions. Tensile bond strengths were measured 24 h after storage in water at 37 degrees C. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses were performed on air-powder polished specimens to determine changes in the surface morphology and detect residual material from the air-powder polisher. SEM and transmission electron microscopic (TEM) observations of the interface between the bonding resins and dentin were performed to detect variations in the hybrid layers of the control and treated specimens. RESULTS: The results indicated that air-powder polishing did not influence the tensile bond strength to enamel, but adversely affected the tensile bond strength to dentin for the one-step systems, but not for the two-step system. Changes to the enamel surface after air-powder polishing were minimal, but an increase in surface roughness and complete removal of the smear layer were observed on dentin. SEM and TEM observations of the resin/dentin interface suggested that the air-powder polisher might cause superficial maceration of the collagen fibers on the dentin surface. This change may have decreased the ability of the etching/priming agents and bonding resin to penetrate into the dentin, which would have resulted in a poor quality hybrid layer. SIGNIFICANCE: For those systems that contain only an acidic primer for dentin conditioning, the use of air-powder polishing for surface preparation prior to restoration of dentin margin cavities is contraindicated because of the loss of reliable bonding.