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M Runkel

Publications and source records attributed to M Runkel.

At least 19 recordsLinked to original sources
PubMed2003

[Indirect MR-arthrography in the follow up of autologous osteochondral transplantation].

PURPOSE: To evaluate the spectrum of findings in indirect MR-arthrography following autologous osteochondral transplantation. PATIENTS AND METHODS: 10 patients with autogenous osteochondral homografts underwent indirect MR-arthrography at three, 6 and 12 months postoperatively. The MR protocol at 1.5 T comprised unenhanced imagings with PD- and T2 -weighted TSE- sequences with and without fat-suppression as well as T1 -weighted fat-suppressed SE-sequences before and after i.v. contrast administration and after active joint exercise. Image analysis was done by two radiologists in conference and comprised the evaluation of signal intensity (Sl) and integrity of the osseous plug and the cartilage surface, as well as the presence of joint effusion or bone marrow edema. RESULTS: At three months, all cases demonstrated a significant bone marrow edema at the recipient and donor site that corresponded to a significant enhancement after i.v. contrast administration. The interface between the transplant and the normal bone showed an increased Sl at three and 6 months in T2 -weighted images as well as in indirect MR-arthrography. The marrow signal normalized in most cases after 6 to 12 months, indicating vitality and healing of the transplanted osteochondral graft. The Sl of the interface decreased in the same period, demonstrating the stability of the homograft at the recipient site. The osteochondral plugs were well-seated in 9/10 cases. Indirect MR-arthrography was superior to unenhanced imaging in the assessment of the cartilage surface. Cartilage coverage was complete in every case. The transplanted hyaline cartilage as well as the original cartilage showed a significant increase of the Sl in indirect MR-arthrography, that did not change in follow up studies. There were no pathological alterations of signal and thickness alterations of the transplanted cartilage in follow up investigations. CONCLUSION: Indirect MR-arthrography is a useful diagnostic tool following autologous osteochondral transplantation. Assessment of transplant vitality, osseous fixation and stability is possible.

Adolescent↗
PubMed2002

Low-field MR arthrography of the shoulder joint: technique, indications, and clinical results.

In the age of cost containment and urgent reductions in health care expenditures, new options have to be explored to satisfy both diagnostic requirements and economic limitations. The introduction of low-field MR systems for assessment of joint disorders seemed to be an option for lower costs. The purpose of this article is to summarize available experiences with low-field MR arthrography of the glenohumeral joint with respect to image quality and diagnostic accuracy in detecting labral and rotator cuff lesions. Up to now, there has been only a limited number of studies available dealing with low-field MR arthrography of the glenohumeral joint. They reveal that, despite a minor image quality in comparison with high-field imaging, low-field MR arthrography of the shoulder allows for sufficient evaluation of intra- and extra-articular structures in the detection of major abnormalities such as glenohumeral instability or rotator cuff disease. Furthermore, open-configured MR scanners enable kinematic studies: Besides the analysis of normal motion, pathological findings in patients with instabilities and impingement syndrome can be delineated. They further offer the possibility for performing MR imaging-guided arthrography of the shoulder. This was first described using an open C-arm scanner with a vertically oriented magnetic field so that MR arthrography may be performed in one setting.

Arthrography↗
PubMed2001

Long-term results after operative treatment of femoral neck fractures with ceramic head prostheses.

From 1985-1990, a total of 277 elderly patients underwent hemiarthroplasty using a ceramic head prosthesis. Average patient age was 81.7 years. Of these, 77 patients were available for follow-up examination in 1993. A standardized score was calculated assessing activity, gait, and hip pain; the average score was 58 out of 78 possible points. Three patients had hip pain, and in 4 patients, radiographic examination revealed protrusio acetabuli. Two of 4 patients underwent revision surgery for replacement of the cup, leaving the stem in situ. Because of the small number of prosthetic-related complications, hemiarthroplasty using a ceramic head prosthesis is the recommended surgical treatment for femoral neck fractures in elderly patients. In the rare patient with protrusio acetabuli, revision surgery can be performed to replace the cup, leaving the stem in situ.

Acetabulum↗
PubMed2000

[Sensitivity of magnetic resonance tomography in detecting meniscus tears].

In order to assure diagnostic accuracy, 172 knee joints were examined prospectively by MRI. After MRI, all knee joints were examined by arthroscopy. Tears of the medial meniscus were found in 102 patients, the lateral meniscus showed a tear in 29 cases. Assuming that arthroscopy represents the golden standard of diagnostic measure concerning the knee joint, it can be stated that false-positive MRI findings on the medial and lateral meniscus were diagnosed in three cases and false-negative MRI findings were diagnosed for two knee joints regarding the medial meniscus and four times regarding the lateral meniscus. For the medial meniscus a sensitivity of 98%, a specificity of 96%, an accuracy of 94%, and the positive and negative value of prediction were calculated at 97% each. Regarding the lateral meniscus, a sensitivity of 85%, a specificity of 98%, an accuracy of 92%, a positive predictive value of 88%, and a negative predictive value of 85% were found. Under the prerequisite that the MRI is carried out correctly and assessed by an experienced radiologist, the accuracy of the MRI for meniscus diagnosis is almost equivalent to the one by arthroscopy. Under these conditions, MRI can be recommended when no safe and sufficient clinical diagnosis can be made. The rate of unnecessary arthroscopies with a pure diagnostic purpose can be lowered significantly by means of MRI.

Adolescent↗
PubMed2000

MR arthrography of the shoulder: comparison of low-field (0.2 T) vs high-field (1.5 T) imaging.

The objective of this study was to compare the image quality, sensitivity, specificity, and diagnostic accuracy of an open low-field MR system (0.2 T) with a standard high-field MR system (1.5 T) after arthrography of the shoulder. Thirty-eight patients either with suspected chronic instability (n = 12) or rotator cuff abnormalities (n = 26) were examined. Intra-articular injection of diluted Gd-DTPA was followed in randomized order either first by imaging on an open 0.2-T system or on a 1.5-T system. The image material was evaluated independently by two radiologists in a blinded fashion with respect to overall image quality and the detection of rotator cuff as well as capsular and labral abnormalities. Surgical correlation was available in 27 (71%) of 38 patients. For both systems, sensitivity and specificity for rotator cuff tears were 100% each, and for labrum pathologies, these values were 100 and 93%, respectively. The agreement for detection of labral pathologies between low-field and high-field examinations was good (kappa = 0.69, kappa = 0.61). For the detection of full-thickness tears of the rotator cuff, the agreement between the low-field and high-field MR examinations was very good and significant (kappa = 0.94, kappa = 1, p < 0.001). Overall image quality was rated good in 17 (45%) and fair in 21 (55%) of 38 cases on the 0.2-T MR system, and good in 32 (84%) and fair in 6 (16%) of 38 cases on the 1.5-T system. Motion artifacts were considered low in 24 (63%) and moderate in 14 (37%) of 38 cases for the 0.2-T system and low in 34 (89%) and moderate in 4 (11%) for 1.5-T system. Based on our results, low-field MR compares favorably to high-field MR in the detection of major abnormalities of the glenohumeral joint, at least when MR arthrography is used. Disadvantages are the duration of the examination and thus the risk of reduced image quality caused by motion artifacts.

Adult↗
PubMed2000

A new method of capillary electrophoresis for metabolites of coumarin.

The metabolism of coumarin has been very widely investigated compared with other natural compounds. We know today that genetic variations lead to human groups with a high or low coumarin-metabolism. An effective capillary-electrophoresis method has been developed to study these effects on metabolic patterns. The seven most important metabolites can be analysed in one step. Therefore also small volume samples can be examined for phase-I-reactions (hydroxylation of coumarin) as well as for secondary reactions (e.g. glucuronidation or decomposition of the lactone-structure).

Animals↗
PubMed1999

Injuries of the lateral collateral ligaments of the ankle: assessment with MR imaging.

The aim of this study was to evaluate the ability of MRI to display injuries of the lateral collateral ligamentous complex in patients with an acute ankle distorsion trauma. The MR examinations of 36 patients with ankle pain after ankle distorsion were evaluated retrospectively without knowledge of clinical history, outcome and/or operative findings. The examinations were performed on a 1. 5-T whole-body imager using a flexible surface coil. The signs for ligamentous abnormality were as follows: complete or partial discontinuity, increased signal within, and irregularity and waviness of the ligament. The results were compared with operative findings in 18 patients with subsequent surgical repair. Eighteen patients with conservative therapy had a follow-up MR examination after 3 months. There was 1 sprain, 3 partial and 32 complete tears of the anterior talofibular ligament, and 5 sprains, 5 partial, and 7 complete tears of the calcaneofibular ligament. There were no lesions of the posterior talofibular ligament. Compared with surgery, MRI demonstrated in 18 of 18 cases the exact extent of anterior talofibular ligament injuries and underestimated the extent in 2 of 8 cases of calcaneofibular ligament injury. In patients with follow-up MRI after conservative therapy, a thickened band-like structure was found along the course of the injured ligament in 17 of 18 cases. The absence of ligament repair after conservative treatment was confirmed during operative revision in one case. The MRI technique allows for grading of the extent of injury of the lateral collateral ligamentous complex after acute ankle strain. It seems to be suitable for monitoring the healing process after conservative-functional treatment of ligament tears.

Acute Disease↗
PubMed1999

Naringenin and interindividual variability in interaction of coumarin with grapefruit juice.

UNLABELLED: Grapefruit juice has been shown to enhance oral bioavailability of several drugs including coumarin. The degree of the interaction is highly variable among the individuals. OBJECTIVE: The aim of the study was to evaluate the interindividual variability in the pharmacokinetic profile of three components of grapefruit juice (naringin/naringenin, scopoletin, umbelliferone) and to compare it with the pattern of coumarin-grapefruit juice interaction. STUDY DESIGN: A two-set clinical study with the participation of 18 healthy volunteers was designed. In the first set of the experiment the total renal recovery of naringenin, scopoletin and umbelliferone within 13 hours after the intake of 1L grapefruit juice was estimated. Four individuals, who had demonstrated extremely high or extremely low excretion of the metabolites in the first set, were selected for the second set. The subjects took 10 mg coumarin with 1L grapefruit juice vs 10 mg coumarin with 1 L water in a cross-over manner. The interaction pattern was evaluated according to the time-course curves of 7-hydroxycoumarin (main metabolite of coumarin) excreted with urine. The detailed time-course excretory profiles of naringenin and scopoletin from grapefruit juice were also obtained. RESULTS: The screening demonstrated a significant interindividual variability in the renal excretion of naringenin (max/min > 15), scopoletin (max/min = 6.2), umbelliferone (max/min = 3.3). The interaction between coumarin and grapefruit juice has been observed by increase in the total recovery of 7-hydroxycoumarin up to 3 mg and by delay in time of its excretion by 2-3 hours. This interaction has been observed in 3 of 4 subjects and correlated with naringenin amounts in the urine. The mechanism and the sites of the interaction, as well as the causes for its wide interindividual variability are discussed in the paper.

Adult↗
PubMed1999

[Low-field MRI of the knee joint: results of a prospective, arthroscopically controlled study].

PURPOSE: To define the diagnostic accuracy of an open low-field MR unit (Magnetom Open, Siemens, Erlangen) in traumatic knee lesions. MATERIALS AND METHODS: The MRIs of 150 patients were prospectively evaluated by two independent readers with different experience levels. The study protocol included a proton-density weighted SE-sequence in the sagittal, a T2.-weighted Flash-2D-sequence in the coronal, and a 3D-acquisition (DESS) in the axial plane. 75 patients were treated either conservatively or operatively. RESULTS: Based on arthroscopy as the gold standard, the sensitivities, specificities, and diagnostic accuracies for lesions of the medial and lateral meniscus, the anterior cruciate ligament (ACL), the hyaline cartilage, and the posterior cruciate ligament (PCL) were 92%, 92% and 92%, 83%, 93% and 92%, 95%, 96% and 96%, 74%, 93% and 85%, and 100%, respectively, for reader 1. The values for reader 2 were 81%, 74% and 77% (medial meniscus), 61%, 86% and 80% (lateral meniscus), 79%, 95% and 91% (ACL), 48%, 91% and 73% (hyaline cartilage), and 100% each (PCL), respectively. There were no statistical differences between the two readers (Fisher's Exact Test, 95%-confidence interval). CONCLUSIONS: Using a time-consuming examination protocol, the diagnostic accuracies of the open low-field MR unit are well comparable to those obtained with mid- or high-field units. Although not statistically significant in this study, the experience level of the examiner seems to be of considerable clinical relevance.

Adult↗
PubMed1998

[Efficacy of ultrasound controlled direct reposition of fragments of the posterior vertebral body facet].

To calculate canal compromise and decrease of midsagittal diameter caused by retropulsion of fragments into the spinal canal we analyzed the pre- and postoperative computed tomographies of 32 patients with unstable thoracolumbar burst fractures treated by USS (universal spine system). Our intention was to examine the efficiency of ultrasound guided repositioning of the dispaced fragments which was performed in all 32 cases. We found a clear postoperative enlargement of canal area (ASP preoperatively 55%, postop. 80%) and midsagittal diameter (MSD preop. 58%, postop. 78%). 10 of 13 patients presented a postoperative improvement of neurological deficit, no neurological deterioration occurred. Fractures with neurological deficit showed more canal compromise (52%) and less midsagittal diameter (MSD compromise 51%) than those without (40% or 39%). There was no correlation between the percentage of spinal canal stenosis and the severity of neurological deficit. Below L 1 the spinal canal is greater than between Th 11 and L 1, so a more important spinal stenosis is tolerated. In case of unstable burst fractures with neurological deficit the ultrasound guided spinal fracture reposition is an effective procedure concerning the necessary improvement of spinal stenosis: an additional ventral approach for the revision of the spinal canal is unneeded. In fractures without neurologic deficit the repositioning of the displaced fragments promises an avoidance of long-term damages such as myelopathia and claudicatio spinalis.

Adolescent↗
PubMed1998

[MRI of knee ligaments: error analysis with reference to meniscus and anterior cruciate ligaments in an arthroscopic controlled patient cohort].

PURPOSE: To categorise discrepancies in findings of the menisci and anterior cruciate ligament (ACL) between arthroscopy and MRI. MATERIALS AND METHODS: The MRIs of 236 patients were retrospectively analysed by an experienced radiologist without knowledge of clinical and/or operative findings. Discrepancies in arthroscopic findings were reevaluated together with the arthroscopist to determine their cause of error. RESULTS: The diagnostic accuracies for injuries of the medial and lateral meniscus and the ACL were 92.4%, 92.4%, and 94.1%, respectively. For the menisci, causes for discrepancies in findings (n = 31) were: overinterpretation of central signal intensities with contact to the meniscal surface but without disturbance of the meniscal contour as a tear (n = 12), insufficient arthroscopie evaluation of the knee joint (n = 11), overlooked tears on MR imaging (n = 6), misinterpretation of normal anatomic structures (n = 1), "magic angle" phenomenon (n = 1), and missed tears at MRI (n = 1). Causes for discrepancies for the ACL (n = 18) were: nearly complete versus complete rupture either at MRI or arthroscopy and vice versa (n = 9), insufficient arthroscopic evaluation (n = 6), insufficient MRI technique (n = 2), and overlooked tear on MR imaging (n = 1). CONCLUSIONS: Discrepant findings between MRI and arthroscopy may be also due to an insufficient arthroscopic evaluation in clinical routine. The close cooperation between surgeons and radiologists improves the understanding of the methods of each other.

Adolescent↗
PubMed1998

[Low-field MR arthrography of the shoulder: early results using an open 0.2T MR system].

PURPOSE: To assess the practicability and image quality of doing MR arthrography of the shoulder using a 0.2T system. PATIENTS AND METHOD: 60 patients (24 with chronic instability, 36 with impingement syndrome) were examined in an open 0.2T MR apparatus (Magnetom Open, Siemens). After the intra-articular injections of 15-20 ml of a 2 mmol Gd-DTPA solution, coronary STIR, T1-weighted, sagittal and axial T2*-weighted FLASH 2D sequences were performed. 21 patients subsequently underwent surgery. RESULTS: Image quality of the T1- and T2*-weighted FLASH 2D sequences was regarded as good or adequate and movement artifacts were minor or moderate. STIR sequences were statistically significantly worse in respect of image quality and movement artifacts (p < 0.001, p < 0.005). The sensitivity and specificity in the diagnosis of rotator cuff rupture as confirmed by surgery was 100% (labrum lesions 100%, 93%). Agreement in the diagnosis of rupture of the supraspinatus and infraspinatus tendons was 0.93 and 0.65. CONCLUSION: MR arthrography of the shoulder using an open 0.2 T MR system provides adequate information concerning the intra articular structures of the joint. The disadvantage is the prolonged duration of the examination with the risk of poor image quality resulting from movement artifacts.

Adult↗
PubMed1998

Retrograde nailing of humeral shaft fractures.

The use of intramedullary nailing in the upper extremity is still controversial. Those who have experience with antegrade nailing have either great enthusiasm or strong criticism for the procedure. Criticism of the procedure is because of the trauma that can occur to the rotator cuff and possible impingement syndrome, which can occur after antegrade nail insertion. The technique of retrograde nail insertion with the unreamed humeral nail is described in detail. In a series of 190 retrograde nailings performed in a prospective multicenter study, the most frequent intraoperative problems were fissure or avulsion at the entry portal (n = 8; 4.2%) and secondary radial nerve palsy (n = 8; 4.2%). All radial nerve palsies recovered spontaneously. Sixty-eight patients were followed up until the fractures healed. There were five (7.4%) bone healing problems. Four of five could be solved with use of the unreamed humeral nail in a second operative procedure, whereas the fifth bone healing problem required plate osteosynthesis. Function of the shoulder and elbow joint was excellent in 89.7% and 88.3% of the patients, respectively. Retrograde humeral nailing is a safe and reliable procedure if done properly. It is a valuable stabilization technique for acute and pathologic fractures and for pseudarthrosis. Bone healing problems after unreamed humeral nailing must be analyzed individually, but they can be treated with the same implant in combination with cancellous bone grafts, reaming, additional hardware, or intrafragmentary compression.

Adolescent↗
PubMed1997

[Magnetic resonance tomography examination of thoracolumbar spinal fractures after fixateur interne stabilization].

To analyse the possible injuries of vertebral segments, especially the disc, after unstable thoracolumbar fractures stabilised with AO internal fixator, we performed magnetic resonance imaging (MRI) of the traumatised region after implant removal. There were two aspects of disc degeneration (DD):(1) biochemical changes and (2) structural damage. MRI detects biochemical processes as one aspect of DD that is often small even in the presence of greater structural damage of the nucleus pulposus caused by fracture. None of the patients presented with structural failure of the anulus fibrosus, which is the essential structural component of the vertebral segments with regard to stability. We observed biochemical changes more often in the lower of the two fracture-adjacent discs and alterations of discal shape more often in the upper of the two, whereas loss of height concerned both discs to approximately the same degree. The supporters of upper-disc resection in thoracolumbar fractures justify their procedure among other things with the structural disc damage, such as alteration of shape and loss of height (altogether more frequent in the upper disc). Our observations that a disc with a structurally altered nucleus pulposus can be biochemically intact and can show an intact anulus fibrosus are arguments in favour of disc preservation. With regard to the upper disc, the widespread opinion that complete and regular disc damage requires a resection has to be revised. The question of whether the lower disc should be resected more often because of its greater biochemical changes cannot be answered by the present study alone. Besides the excellent static information in all anatomical structures of the vertebral column available by MRI, a repeat examination in a prone position yields dynamic information on the spinal cord in the case of suspected dorsal adhesions.

Adolescent↗
PubMed1997

The character of inhibition of the metabolism of 1,2-benzopyrone (coumarin) by grapefruit juice in human.

OBJECTIVE: Constituents of grapefruit juice are known to interfere with mammalian cytochrome P450 isozymes such as intestinal CYP3A4 and hepatic CYP2A6, lowering the biotransformation of drugs and increasing their bioavailability. The aim of this study was to investigate whether the presence of naringin is demanded for the inhibition of the coumarin 7-hydroxylase in man or other compounds are responsible for it. METHODS: In cross-over studies, doses of 10 mg coumarin, together with combinations of grapefruit juice, water and naringin, were given orally to one healthy male volunteer, We investigated increasing amounts of grapefruit juice, keeping the volume of liquid constant at 1 L; increasing doses of naringin given in water; increasing amounts of juice, keeping the dose of naringin constant; or increasing doses of naringin, keeping the amount of juice constant. Urine samples were collected up to 24 h after dosing and 7-hydroxycoumarin was quantified fluorimetrically in urine hydrolysates after HPLC separation to determine the excretion rates. RESULTS: While increasing amounts of grapefruit juice delay the excretion of 7-hydroxycoumarin by 2 h, increasing doses of naringin in water up to twofold (i.e. naringin content of 2 L grapefruit juice) do not cause any alteration in the time course of excretion. Experiments with increasing amounts of juice, keeping the dose of naringin constant, indicate that the inhibitory potency of small amounts of grapefruit juice can be amplified by naringin. The same is true when the ratio between juice constituents and naringin is enhanced up to threefold by adding naringin. CONCLUSION: As naringin alone is ineffective, the inhibitory effect of grapefruit juice on the metabolism of coumarin is caused by at least one compound other than naringin. The persistency of the primary inhibitor not identified yet can obviously be modulated by the naring(en)in-system.

Anticoagulants↗
PubMed1997

Minimally invasive plate fixation in femoral shaft fractures.

Bridge-plating with its advantages in terms of vascularity and bone healing is a well established procedure today in the treatment of comminuted femoral fractures. Bridge-plating means that the fracture site is not interfered with during the operative procedure. This paper introduces a surgical technique in which the plate is inserted through isolated proximal and distal incisions only, behind the vastus lateralis. Alignment is secured by the plates, the fracture site remains untouched, fixation and screw insertion is restricted to the proximal and distal main fragments. Longitudinal femoral fractures extending right into the trochanteric and or condylar areas are the main indication for minimally invasive plate fixations with angled blade plates or condylar screws since fractures which are restricted to the diaphyseal area are mostly treated by nailing today. The surgical trauma resulting from plating by proximal and distal incisions only is less than that associated with conventional techniques. Indirect reduction of femoral fragments is much easier since the integrity of the surrounding muscles and soft tissue is preserved, the fragments often being reduced simply by traction. Adjustment of rotation is an essential aspect requiring careful attention. For special indications, namely comminuted fractures affecting a large part of the femur and extending into the trochanteric or condylar areas, insertion of the plate via proximal and distal incisions only is a further development in bridge-plating which minimizes surgical trauma and operation time.

Bone Plates↗
PubMed1997

[Use of information systems for direct surgical patient management].

The aim of this prospective study was to evaluate the use of a modern computer-based hospital information system for the management of patients in our surgical department. The results showed that the information system was well accepted by the medical staff and found to be useful throughout daily work. In addition, they justify the effort to install and maintain such a system.

Attitude to Computers↗