Border Distance Research Articles

Simplified MRI sequences for postoperative control of hamstring anterior cruciate ligament reconstruction.

Usually, standard radiographs are used for postoperative quality follow-up after ACL reconstruction. However, with the use of hamstring grafts and bioabsorbable implants, accurate assessment of the tunnel and implant position is impossible. The graft and its relation to anatomical landmarks cannot be evaluated directly. MRI is an alternative to radiography, permitting direct graft visualization and 3-dimensional assessment of the tunnel position, but it is expensive and time consuming for routine use. The aim of this study was to develop a simplified MRI protocol and to evaluate it for routine postoperative quality follow-up after ACL reconstruction. Various scanning protocols were tested in a series of 105 patients and evaluated for image sharpness, clarity of the structures, susceptibility to artefacts, applicability regarding precise analysis of graft and tunnel position, and time consumption. One simplified specific scan protocol was then defined and applied in a series of 60 consecutive patients after hamstring ACL replacement. The position of the femoral and tibial tunnels was measured in the sagittal, coronal and axial sections and classified according to Harner (femoral) and Stäubli (tibial). Impingement of the graft in the intercondylar roof was analysed according to Howell. The position of the bioabsorbable interference screws was assessed. Scan protocol: T2-weighted gradient-echo sequences (GRE) with TR 246 ms, TE 11 ms, flip angle 25 degrees, 2 mm sections and a 256 x 256 matrix yielded the best image quality of tendon grafts and bone tunnels with tolerable time consumption (average scanning time per patient 1 min 40 s). Altogether 8-16 sections were obtained for every patient. Tunnel placement: 46/60 (77%) of the femoral tunnels were in zone 4, 13/60 (21%) at the border of zones 3 to 4, 1/60 (2%) in zone 3 in the sagittal plane (Harner). The femoral tunnels in the axial plane were at 10:30 o'clock in 32/60 (53%), at 11:00 o'clock at 24/60 (40%) and at 10:00 o'clock in 4/60 (4%) patients. The mean distance of the anterior border of the tibial tunnel from the anterior cortex was 39% (+/- 4.9%) related to the total sagittal diameter of the tibia. There was no graft impingement. The position of the interference screws was anterior to the grafts in all cases. Simplified MRI sequences can be used for postoperative quality follow-up after ACL replacement and are an alternative to standard radiographs giving more specific and precise information regarding tunnel position and screw placement. Analyzing the bone tunnels in a series of 60 patients demonstrated that correct assessment of tunnel placement after arthroscopic ACL reconstruction is feasible using this simplified MRI technique.

Laparoscopic resection of submucosal tumor on posterior wall of gastric fundus.

Laparoscopic resection of tumors on the posterior wall of gastric fundus, especially when they are next to the esophagocardiac junction (ECJ), is both difficult and time-consuming. Furthermore, it can lead to inadvertent esophagus stenosis and injury to the spleen. In order to overcome these difficulties, laparoscopically extraluminal resection of gastric fundus was designed to manage submucosal tumors located on the posterior wall of gastric fundus and next to ECJ. From January 2001 to September 2003, laparoscopically extraluminal resection of gastric fundus was successfully carried out on 15 patients. There were 11 males and 4 females with an average age of 58 years (range, 38 to 78 years). The mean diameter of the tumors was 4.8 cm. The distance of the tumor border from ECJ was about 1.5-2.5 cm. The four-portal operation procedures were as follows: localization of the tumor, dissection of the omentum, mobilization of the gastric fundus and the upper polar of spleen, exposure of ECJ, and resection of the gastric fundus with Endo GIA. The laparoscopic operation time averaged (66.2+/-10.4) min, the average amount of bleeding was (89.4+/-21.7) mL. The mean post-operative hospital stay was (5.3+/-1.1) d. Within 36 h post-operation, 73.3% of all the patients recovered their gastrointestinal function and began to eat something and to walk. In all the operations, no apparent tumor focus was left and no complication or conversion to open surgery occurred. Our newly designed procedure, laparoscopically extraluminal resection of the gastric fundus, can avoid contamination of the abdominal cavity, injury to the spleen and esophageal stenosis. The procedure seems to be both safe and effective.

Ultrasound biomicroscopy and scheimpflug photography of angle-supported phakic intraocular lens for high myopia

Purpose To evaluate the equivalence of Scheimpflug photography (SP) and ultrasound biomicroscopy (UBM) in determining corneal epithelium−intraocular lens (IOL) and border IOL−iris distances. Setting Universität Erlangen-Nürnberg, Erlangen, Germany. Methods In 26 eyes of 17 patients who had a NuVita MA20 angle-supported anterior chamber intraocular lens (Chiron-Domilens), SP and UBM were used to evaluate the distance between the endothelium and the anterior IOL face in central and peripheral regions (12 o’clock and 6 o’clock positions) and between the border of the anterior IOL face and the iris. The Wilcoxon test was used for statistical analysis. Results The mean central endothelium−anterior IOL face distance was 2.01 mm and 2.00 mm by SP and UBM, respectively. The mean peripheral endothelium−anterior IOL border distance was 1.28 mm and 1.58 mm, respectively, and the mean peripheral anterior IOL face−iris distance, 0.89 mm and 0.75 mm, respectively. Conclusions The difference between the 2 methods in the central endothelium−anterior IOL face distance was not significant (methods were equivalent), but the difference in the peripheral endothelium−anterior IOL face distance was. This may be the result of difficulty in obtaining the exact transition point between the IOL and the haptics by SP examination. The difference between the 2 methods in the IOL border−iris distance was also significant because of the irregularity of the iris surface; therefore, measurements were performed at different sites along this structure. The significant differences in the peripheral endothelium−IOL and IOL border−iris distances indicate that although both methods are useful, they are not equivalent.

How Wide Are European Borders? New Evidence on the Integration Effects of Monetary Unions

We use consumer price data for 81 European cities (in Germany, Austria, Switzerland, Italy, Spain and Portugal) to study deviations from the law-of-one-price before and during the European Economic and Monetary Union (EMU) by analysing both aggregate and disaggregate CPI data for 7 categories of goods we find that the distance between cities explains a significant amount of the variation in the prices of similar goods in different locations. We also find that the variation of the relative price is much higher for two cities located in different countries than for two equidistant cities in the same country. Under EMU, the elimination of nominal exchange rate volatility has largely reduced these border effects, but distance and border still matter for intra-European relative price volatility.

Management of severe traumatic brain injury by decompressive craniectomy.

The beneficial effect of decompressive craniectomy in the treatment of head trauma patients is controversial. The aim of our study was to assess the value of unilateral decompressive craniectomy in patients with severe traumatic brain injury. We retrospectively investigated 49 patients who underwent decompressive craniectomy. Intracranial pressure, cerebral perfusion pressure, therapy intensity level, and cranial computed tomographic scan features (midline shift, visibility of ventricles, gyral pattern, and mesencephalic cisterns) were evaluated before and after craniectomy. The gain of intracranial space was calculated from cranial computed tomographic scans. Patient outcome was graded using the Glasgow Outcome Scale. Thirty-one patients (63.3%) underwent rapid surgical decompression within 4.5 +/- 3.8 hours after trauma; in 18 patients (36.7%), delayed surgical decompression was performed 56.2 +/- 57.0 hours after injury. Patients younger than 50 years or patients who underwent rapid surgical decompression had a significantly better outcome than older patients or patients who underwent delayed surgical decompression. Craniectomy significantly decreased midline shift and improved visibility of the mesencephalic cisterns. The state of the mesencephalic cisterns correlated with the distance of the lower border of the craniectomy to the temporal cranial base. Alterations in intracranial pressure, cerebral perfusion pressure, and therapy intensity level were not significant. The overall mortality of the patients corresponded to the reports of the Traumatic Coma Data Bank (1991). Although there was a significant decrease in midline shift after craniectomy, this did not translate into decompressive craniectomy demonstrating a beneficial effect on patient outcome.

Interregional Cooperation in Higher Education in Europe'

This article drau's on the preparatory research. discussions and conclusions of a conference on1 Regional Cooperation and Mobility in Higher Education jointly organized in September 1997 in Iceland by the Council of Europe and the Nordic Council of Ministers. Regional cooperation is defined as cooperation between sub-national regions" (either across a common border or longer distance). or between such regions " and/or countries located within a relatively small geographical area of Europe. The article introduces a number of very, diverse cooperation schemes fitting these definitions. It examines the nature and purpose of inter-regional cooperation in higher education, its relationship with other types of international cooperation in higher education and its role within overall inter-regional cooperation. Kei determinants of the future development of inter-regional cooperation in higher education are identified and scenarios and recommendations for the future proposed. The article demonstrates that regional cooperation is a complement to, and in no

Determination of the unit size of the corneal endothelial cell mosaic from Fourier component image analysis

Scanning electron micrographs were taken of the central region of the corneal endothelium of cows (Holstein). The cells were outlined and an image overlay generated of approximately 100 cells. Via a Windows-based scanning system, the overlay was subjected to a two-dimensional Fourier transform on a Unix-based system. A custom algorithm was developed (IRIS) to sequentially analyse the Fourier transform pattern. The transform and resultant harmonics spectrum were compared to those obtained from artificial cell mosaics generated from uniform sized symmetrical hexagons. The position, width, and height of the 1st harmonic component of the frequency distribution appears to be derived from average cell-cell border distances across the image. The radial position of the 1st harmonic is inversely related to the unit cell size in the mosaic, i.e. the dominant cell size. The application of such techniques to cell mosaic analyses is discussed.

Measurements of scapular position and rotation: a reliability study.

Smooth motion of the scapula and humerus with respect to the thorax is essential for shoulder function and abnormalities may indicate clinical entities. Recent studies have made an attempt to devise simple, practical means of quantifying scapular position. The aim of this study was to examine the intra-tester and inter-tester reliability of two methods and to determine if significant differences existed between the dominant versus non-dominant extremity. Seventeen healthy volunteers (4 M; 13 F) were examined by two testers. The tape measurements consisted of the classic methods of Kibler and DiVeta in three sitting postures, expanded by the measurement of the linear distance from the medial border to the thoracic mid-line, and the scapular size measure. The SAS software package was used for data analysis. The Intraclass Correlation Coefficient (ICC) intra-tester reliability ranged between 0.96-0.8 for both methods without significant differences, whereas the ICC for inter-tester reliability ranged between 0.42-0.9 with higher values (moderate and good) for the Kibler technique. In the additional tests high values were also obtained for ICC intra-tester, except for the measurements of the linear distance of the medial border of the scapula to the thoracic mid-line and the distance of the inferior process of the acromion to the third vertebra, both in 90 degrees abduction and internal rotation. The ICC for inter-tester was only acceptable for the DiVeta measurement on 45 degrees abduction. Significant differences were noted between both testers on the following measures: Kibler in 45 degrees abduction, DiVeta in 45 degrees abduction and 90 degrees abduction and the scapular size measure. The comparison of dominant versus non-dominant extremity revealed larger but not significantly different means for the dominant extremity in the classic methods. Significant differences occurred for Tester 1 in the measurement of the distance of the medial border to the thoracic mid-line and Tester 2 in DiVita in 45 degrees abduction. The SEM values never exceeded 1 cm. We believe that the Kibler technique holds promise for further studies, has the advantage of measuring in three positions and with some familiarisation can be reliable. Further research is necessary in patients with pathological conditions.

Three-level charge pumping study of radiation-induced defects at SiSiO 2 interface in submicrometer MOS transistors

The charge pumping response of interface traps and near-interfacial oxide traps (border traps) induced by Co 60 gamma rays in submicrometer (0.5 μm channel length) metal-oxide-semiconductor transistors has been studied. Using an improved three-level charge pumping technique, the energy distribution of interface trap parameters (emission times, capture cross-sections and interface state density) has been determined after irradiation in both the upper and lower parts of the silicon band gap on n-channel devices. The influence of border traps on three-level charge pumping measurements is demonstrated for the first time. Good agreement has been found between standard charge pumping and three-level charge pumping characteristics in terms of ‘breakpoint frequency’ at which the charge recombined per cycle deviates from the fast interface state response. The distance of border traps from the interface has been estimated to be ∼ 15–20 Å from a trap-to-trap tunneling model. In addition, a new technique is presented based on three-level charge pumping measurements to determine a border trap distribution in the silicon band gap.

Vertebral Artery Location in Relation to the Vertebral Body As Determined by Two-Dimensional Computed Tomography Evaluation

Study Design This study analyzed the precise two-dimensional location of the vertebral artery within cervical vertebrae as determined by measurements obtained from axial computed tomogaphic images of the cervical spine. Objective to determine the margin of safety necessary to avoid vertebral artery laceration during central decompression and lateral nerve root decompression for cervical spinal stenosis. Summary of Background Data Laceration of the vertebral artery is a rare but potentially catastrophic complication of anterior decompressive surgery of the cervical spine. Methods The mean, standard deviation, and 95% confidence interval of the mean of measurements localizing the vertebral artery within the vertebral body were calculated from 50 transaxial computed tomography images of each of the second through sixth cervical vertebrae. Results Bothe the mean interforminal distance (from 25.90% ± 1.89 mm at C3 to 29.30 ± 2.70 mm at C6) and the average distance of the posterior border of the foramen transversarium from the ventral border of the spinal canal (from 2.16 ± 1.18 mm at C3 to 3.53 ± to 3.53 ± 1.56 mm at C6) increased from C3 to C6. Conclusions According to our measurements, the risk of vertebral artery laceration is greater at more cephalad vertebrae during lateral extension of central decompressive procedures and lateral nerve root decompression. Because of the variability of these parameters between individuals, accurate individual preoperative localization of the vertebral arteries is recommended.

Extraocular muscle surgery in a rabbit model: site of reattachment following hang-back and conventional recession

To determine the precise site of reattachment of recessed muscles, 4-mm conventional and hang-back recessions of the inferior rectus muscle were performed in 18 albino rabbits. Six weeks later, the distance from the anterior border of the reattached muscle to the insertion was measured both grossly and microscopically. In all cases the operated muscles had advanced minimally from the site of surgical placement. Gross observation showed that the mean forward creep was significantly greater for those rabbits which underwent hang-back recession (1.81 +/- 0.67 mm) than for those that were submitted to the conventional technique (0.83 +/- 0.38 mm). Measurements done on histological sections revealed that the mean distance of the anterior border of the muscle fiber from the reference suture was larger for conventional recession (2.73 +/- 0.75 mm) than for hang-back recession (1.91 +/- 0.72 mm).

Relationship Between Attachment of the Superficial Masseter Muscle and Craniofacial Morphology in Dentate and Edentulous Humans

Previous studies have described the importance of the interaction between the masticatory muscles and the craniofacial skeleton in the control of craniofacial growth. This study describes the attachment and orientation of the superficial masseter muscle and its relationship with craniofacial morphology in dentate and edentulous subjects. Data were obtained from lateral cephalometric radiographs of a total of 31 cadavers in which the superficial masseter muscle had been defined with liquid barium. The results provide evidence that the morphology of the superficial masseter muscle in the gonion region differed significantly between dentate and edentulous subjects, with the masseter being 2.7 mm wider and the gonion-anterior muscle border distance being 4.0 mm greater in dentate subjects. The complex relationship between craniofacial morphology and the dimensions and inclination of the superficial masseter muscle were most clearly evident in dentate subjects where the position of the anterior border was related to ramus dimensions and mandibular and occlusal plane angles. The association is much less clear in edentulous subjects where normal function was disturbed. In general, age was not a significant determinant of variation in superficial masseter muscle dimensions and orientation.