Biomedical subjects

K Stoffel

Publications and source records attributed to K Stoffel.

5 recordsLinked to original sources

PubMed2007

The SLAP lesion as a reason for glenolabral cysts: a report of five cases and review of the literature.

INTRODUCTION: Cysts in the spinoglenoidal or supraglenoidal incisura can be a cause of compression of the suprascapular nerve. There is agglomerated appearance of these cysts in combination with SLAP lesions. Hypothesis is SLAP lesions can lead to cysts in this region and should be repaired. MATERIAL AND METHODS: MRI of five patients (all male, four 30-40 years, one 75 years) showed cysts in the supralabral region. All were in combination with lesions of the superior glenoidal labrum (Type II or more). RESULTS: In two cases, in addition to cyst resection, the SLAP lesion was also repaired and symptoms disappeared completely and no recurrent cyst was detected in postoperative MRI. Two patients without SLAP repair showed recurrent cystic formation in MRI with similar complaints compared to their preoperative status. One patient (75 years) was treated primarily by puncture and afterwards with open resection of the cyst. His outcome was good in terms of activities of daily living without major pain. CONCLUSIONS: Our results are based on the assumption that cysts in the region of the spinoglenoidal/supraglenoidal incisura can originate from SLAP lesions. If a patient is suspected of having cysts in this region, the question of a SLAP lesion should be clarified. SLAP lesions should be repaired to avoid relapse. Arthroscopic repair of SLAP lesion can lead to the disappearance of symptoms in younger patients. In older patients puncture or resection of the ganglion alone may be an adequate therapeutic strategy.

Adult↗

PubMed2000

Functional load of plates in fracture fixation in vivo and its correlate in bone healing.

In clinical practice efforts are made to apply a fixation plate on the side opposite the strongest muscle pull. This achieves an optimal distribution of compression between the fragment ends (principle of tension band plating). This is however frequently impossible for anatomical or surgical reasons. In an 'in vivo' study lasting 8 weeks a standardized oblique osteotomy was performed on the tibia of 16 sheep in four different models of tension band plating (a contoured and an overbent plate with or without an interfragmentary lag screw) were assessed. Tension on the plate surface was recorded by strain gauges for different gait speeds on the treadmill. These measurements were performed throughout the experiment. Radiographs were taken at regular intervals in order to assess stability and polychrome sequential labelling and microradiographs served to investigate the healing process. Possible relationships and/or interactions between plate tension and bone healing were investigated. Implant loading under bending strain was reduced the most for the combination of plate overbending with a lag screw. The insertion of a lag screw reduces the surface strain on the plate whether it is contoured or overbent. The bending and torsional forces are greatest if a straight plate is used alone and the principle of tension band plating is not applied. Direct bone healing was only observed in the group with contoured plate and lag screw. Overbending combined with a lag screw provided only a relatively unstable fixation. A residual gap immediately beneath the plate permits "dynamic compression" since the screws slide towards the osteotomy when loaded producing bone resorption under the plate and signs of screw loosening. The models with contoured and overbent plates without a lag screw were histologically assessed as very unstable with signs of secondary fragment displacement, obvious callus formation, resorption at the fragment ends and under the plate, delayed and diminished Haversian remodelling and corrosion sites at the screw heads and at the adjacent site on the plate hole. In all groups, stripping of the periosteum under the plate was associated with porosis of the corresponding cortex as a sign of temporarily impaired blood supply. A relationship between implant loading and/or unloading (stress shielding) could not be demonstrated. Callus formation, measured quantitatively on the radiographs, is directly related to the strain on the plate. Direct bone healing is rapid and is seen histologically three weeks postoperatively, particularly for fixations with contoured plate and lag screw. The early appearance of fixation callus in the presence of an intact blood supply indicates a primary instability of the osteosynthesis. Later, it may be an indication of secondary instability. The time at which osteons appear, their number and location provides information on the stability of the osteosynthesis. At a time when indirect fracture reduction and stabilization using minimally invasive techniques and implants is being propagated, additional ways and means must be sought to assess clinically the load on the implants and the risk of implant failure.

Animals↗

PubMed1998

A graphical tool for ad hoc query generation.

Medical data are characterized by complex taxonomies and evolving terminology. Questions that clinicians, medical administrators, and researchers may wish to answer using medical databases are not easily formulated as SQL queries. In this paper we describe a graphical tool that facilitates formulation of ad hoc questions as SQL queries. This tool manages multiple attribute hierarchies and creates SQL query strings by navigating through the hierarchies. This interactive tool has been optimized using indexing to improve the overall speed of the query building and the data retrieval process. Indexed queries performed 5 to 100 times faster than query strings. However, query string generation time depends on the size of the taxonomies describing the hierarchies, while the index generation time depends on the size of the data warehouse.

Abstracting and Indexing↗

PubMed1993

[Quantification of the intra-penile smooth muscle with a fuzzy logic algorithm].

We have developed a new computer program for tissue segmentation designed for the quantification of smooth muscle in the corpus cavernosum. The program uses digitalized images of stained histological sections taken with a CCD camera. The recognition of the different tissues is based on the examination of absorption of monochromatic light. The section is successively illuminated with light of three different wavelengths and the three absorption values and texture parameters are used for the identification of the tissue using a fuzzy algorithm.

Absorption↗

PubMedDate not supplied

[Relevant differences after post-traumatic and degenerative humeral head replacement (intermediate-term results)].

INTRODUCTION: In a comparative study, mid-term findings after posttraumatic and degenerative hemi-prosthetic shoulder joint replacement were analyzed and compared with current reports in the literature. METHODS: The patient sample in the retrospective study consisted of 20 patients with proximal fractures of the humeral head (x = 64 years) and 6 patients (x = 61 years) with degenerative shoulder joint disease. In 14 patients the humeral head was replaced as a primary procedure at < 4 weeks after the trauma and in 6 patients as a secondary treatment at > 4 weeks. The follow-up period was 38-41 months on average. Evaluation was based on the Constant Score, subjective assessment by the patient, and conventional radiographs. RESULTS: After posttraumatic shoulder replacement, the patients achieved a Constant Score of 65 (+/- 19) and after degenerative replacement 74 (+/- 34) points. In the posttraumatic group, the Constant Score after primary implantation was better than after secondary implantation (68 +/- 16 versus 59 +/- 15 points). After posttraumatic replacement, the only improvement over time was in pain levels (p < 0.05). 92% of all patients were satisfied with the result and would accept the same treatment again. Radiologically, a clinical correlate could be found for the arrosions at the acromion and occasionally for the secondary upwards displacement of the humerus. The results correlated well with data from the literature. CONCLUSIONS: For posttraumatic conditions, hemiarthroplasty led to better results within four weeks and seemed to be a suitable alternative to other procedures, especially in older patients. Patients with primary osteoarthritis and idiopathic humeral head necrosis can expect good to excellent results after hemiarthroplasty. In both groups, the overall results depend mainly upon patient compliance and the state of the rotator cuff.

Aged↗