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Biomedical subjects

W E Siebert

Publications and source records attributed to W E Siebert.

18 recordsLinked to original sources
PubMed1997

Photodynamic therapy for rheumatoid arthritis?

BACKGROUND AND OBJECTIVE: The only early surgical therapy of rheumatoid arthritis is synovectomy. But even an arthroscopic synovectomy is restricted to more or less big joints. It has been shown recently that for smaller joints a laser synovectomy is possible but more time-consuming than with mechanical instruments. An alternative method may be photodynamic therapy. STUDY DESIGN/MATERIALS AND METHODS: In this study, possible photodynamic effects of Chloroquine, Methotrexate, Piroxicam, and Sodium Morrhuate were examined using a cell culture model of human synovial fibroblasts from patients having rheumatoid arthritis. RESULTS: Incubation with Chloroquine or Methotrexate and subsequent laser irradiation at a wavelength of 351 nm resulted in an at least twenty-fold enhanced cytotoxicity. CONCLUSION: Both substances therefore may serve for a photodynamic therapy of rheumatoid arthritis.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Photodynamic laser therapy for rheumatoid arthritis. Cell culture studies and animal experiments.

The introduction of arthroscopic techniques has improved the surgical therapy of rheumatoid arthritis. The additional application of the holmium:yttrium aluminum garnet (Ho:YAG) laser likewise holds great promise by providing complete hemorrhagic control. Unfortunately, a minimally invasive solution for use in smaller joints has not yet emerged. The present study describes the possible treatment of these joints by means of photodynamic laser therapy. Cell culture studies with human synovial fibroblasts obtained from patients with rheumatoid arthritis have demonstrated a cytotoxic effect after administration of Photosan-3 as a photosensitizer and subsequent laser irradiation at 630 nm. for the in vivo studies, IgG-induced arthritis in rabbits, which is histologically consistent with the proliferative phase of rheumatoid arthritis, was used as the animal model. The histologic picture following photodynamic laser therapy with Photosan-3 revealed complete synovial destruction which also extended to the border of the subjacent joint capsule. In contrast, bradytrophic structures, e.g. cartilage. menisci, and ligaments, remained unchanged at both the macroscopic and microscopic levels. Therefore, photodynamic laser therapy can be considered a new method in the surgical treatment of inflammatory disease of the synovial membrane. It has the advantage of being minimally invasive, while offering a high degree of efficacy and selectivity.

Animals↗
PubMed1997

Holmium: YAG-laser-assisted arthroscopy versus conventional methods for treatment of the knee. Two-year results of a prospective study.

The results of 320 arthroscopic procedures are reported here, in which laser surgery using the holmium: YAG laser is compared with conventional mechanical methods. The patients were followed-up during a 2-year period and the data analyzed in a prospective study. The following knee injuries were included: meniscal lesion, chondromalacia, combined meniscal/cartilage lesion, rheumatoid synovialitis and patellofemoral pain syndrome. Because strict inclusion criteria were used, the patient collective is homogenous. Gender, age, injured side, intrasurgical diagnosis, and the initial values of the Lysholm score (modified after Klein) are congruous. After 2 years, the results of the laser collective were significantly improved, whereas the results for the conventional collective, especially for chondromalacia and synovialitis, did not show the same improvement. Analysis of the effect of various instruments and the laser system itself show differing results for the various knee disorders. The hemostatic effect of the holmium: YAG laser was excellent during surgery of all knee disorders, including surface treatment. Operating time for laser surgery was not prolonged, in contrast to what is often claimed. This study shows that chondromalacia, combined meniscal-cartilage lesions, and chronic rheumatoid synovialitis are treated more effectively and with better results with the holmium: YAG laser than with conventional arthroscopic methods. Furthermore, laser treatment of lateral retinacular release can be considered to be better than mechanical techniques. No significant advantage can be found for using the laser during meniscectomy. Lasers are useful for treating smaller, hard-to-reach joints and lower the risk of iatrogenic cartilage damage. The holmium: YAG laser is a suitable instrument for arthroscopic surgery.

Adolescent↗
PubMed1997

Mutagenic effects of the Excimer laser using a fibroblast transformation assay.

For over 10 years fiber-guided laser systems have been used in arthroscopic surgery. The possibility of a mutagenic risk by the use of lasers has not been sufficiently repudiated, especially for the Excimer laser at a wavelength of 308 nm, which is close to the absorption spectrum of DNA. The aim of this study therefore was to approximate the mutagenic risk of UV-laser wavelengths using an in vitro transformation assay. BALB/3T3 fibroblasts were irradiated with Excimer laser wavelengths of 248 nm and 308 nm. The resulting transformation rates were compared to those of untreated cells and to cells that were subjected to an x-ray dose of 1 Gy. Pulse energy, frequency, and irradiation time were varied over a wide range, from sublethal fluences to total cell death. Furthermore, the effect of repeated irradiation (split-dose) was analyzed. The results for the 248 nm irradiation showed a highly significant transformation rate (P < 10(-9)). In contrast, results for the 308 nm irradiation were not at all significant (P < .18). The transformation rate of cells that were treated with x-rays was increased exponentially compared with the controls. Although an increased transformation rate was found after 248 nm irradiation, that of the wavelength 308 nm was not enhanced. The study therefore shows that the use of the Excimer wavelength 308 nm in arthroscopic procedures does not imply a specific mutagenic risk.

Animals↗
PubMed1996

[Magnetic resonance imaging and temperature measurement in cartilage following laser therapy].

The aim of this study was the dynamic measurement, with magnetic resonance imaging, of temperature in cartilage irradiated by laser. Fresh specimens, each with chondromalacia grade II and III, were irradiated with a Holmium:YAG laser under MRI control. Temperature was measured by means of the proton-shift method, which allows high temporal and spatial resolution. With this method a maximum increase in temperature of 35 degrees was found after irradiation with 1.0 J and 10 Hz for 5 s at a distance of 1 mm. In no case at all was an increase in temperature of more than 10 degrees observed in the cartilage adjacent to the subchondral bone. These results exclude the possibility of significant thermal damage from laser treatment as described.

Cadaver↗
PubMed1996

[Temperature and ablation measurements in laser therapy of intervertebral disk tissue].

We experimentally tested the effect of Laser light at wavelengths of 1064 nm, 1320 nm, 1440 nm and 2100 nm on intervertebral disc tissue. The tested parameters were tissue ablation, determined by weight reduction, and temperature change, measured with thermoelements. We used bovine nucleus pulposus tissue for ablation measurement and human spine segments for temperature measurement. We found that variation of single parameters such as power, frequency and energy per pulse had only a slight effect on ablation. The decisive factor for the mass of tissue ablated seems to be the total applied energy. One indispensable requirement is a suction unit; we procured a manifold increase in ablation rate using suction. In the investigations of tissue temperature, we found no risk to upper or lower plate when the fiber was centered correctly in the disc. Within a distance of 10 mm from the fiber tip, the temperature development was found to be radial, so no more tissue damage is to be expected in front of the tip than to the side of it. Although the various wavelengths tested are absorbed differently in water there were only small differences in temperature. Using a neodymium: YAG laser with a fiber of 400 micron diameter, we sometimes measured high cannula temperatures, showing that case one has to be exercised, especially with high energies. In conclusion, it can be said that both the Holmium:YAG laser and the neodymium:YAG laser are suitable for disc decompression with the parameters used currently in surgery.

Animals↗
PubMed1996

[Experimental bases for photodynamic laser therapy in chronic polyarthritis].

The principle of photodynamic laser therapy (PDT) for chronic polyarthritis consists in specifically concentrating a drug (photosensitizer) in the synovium. Subsequent activation of the photosensitizer by means of laser leads to a cytotoxic effect. The practicability of PDT was first shown in cell cultures of human synovial fibroblasts. For further tests an animal model consisting of IgG-induced arthritis in rabbits was used. In this model, concentration of the photosensitizer in the synovial lining cells, in the media of arteries and in the lymphoid infiltrate was seen. After laser irradiation there was total selective demarcation of the synovium. In contrast, bradytrophic tissues such as cartilage, meniscus and ligament structures were changed neither macroscopically nor microscopically. In the animal model PDT combines high selectivity with minimal invasiveness and can be used in small joints. PDT thus offers ideal preconditions for future minimal invasive treatment of chronic inflammatory joint diseases.

Animals↗
PubMed1996

[Percutaneous laser disk decompression. Experience since 1989].

Since 1987/1988 percutaneous laser disc decompression (PLDD) has been used clinically for treatment of intervertebral disc prolapses. Credible prospective investigations that have been conducted since 1989 with large patient collectives are now available for analysis of their medium-term results and comparison with other minimally invasive procedures. Our follow-up examination of the first 180 patients treated with PLDD from 1989 to 1993 shows a success rate of 72.8%, similar to that with other percutaneous techniques (automated percutaneous lumbar discectomy, percutaneous lumbar discectomy, chemonucleolysis). To guarantee success, the spinal surgeon must have command of the correct technique and also use the appropriate instruments. Good results with the PLDD procedure can be procured when contraindications and indications for patient selection are strictly observed. Overall, our 5 year results seem encouraging.

Adult↗
PubMed1996

[Arthroscopic holmium-YAG laser compared to conventional procedures on the knee joint. 2-year results of a randomized prospective study].

The results of 320 patients after holmium:YAG laser treatment in comparison to conventional mechanical methods during a 2-year period were analyzed in a prospective, randomized study. The following knee injuries were included in the study: meniscal lesion, chondromalacia, combined meniscal/cartilage lesion, rheumatoid synovitis and femoropatellar pain syndrome. Because strict inclusion criteria were used, the patient series is homogeneous, not only in terms of sex, age, injured side and intrasurgical diagnosis, but also because the initial values of the Lysholm score modified after Klein are similar. After 2 years, the results of the laser series were significantly improved, whereas the results for the conventional series, especially for chondromalacia and synovitis, did not show the same improvement. Analysis of the effect of various instrumentation and the laser system itself show differing results for the different knee disorders. The hemostatic effect of the holmium-YAG laser was excellent during surgery for all knee disorders, including surface treatment. The operation time for laser surgery was not prolonged, as is often stated. This study shows that chondromalacia, combined meniscal-cartilage lesions and chronic rheumatoid synovitis are treated more effectively and with better results with the holmium-YAG laser than with conventional arthroscopic methods. Furthermore, laser treatment of meniscectomy and lateral retinacular release is also better than mechanical techniques. This study demonstrates the feasibility of the holmium-YAG laser for arthroscopic surgery. A combination of different instruments seems to be most effective.

Adolescent↗
PubMed1993

[Overuse syndrome in ballet: study of the effect of a tape bandage of the upper ankle joint with motion analysis].

In six ballet dancers with overuse syndromes of the foot a study on the effect of taping on stabilisation, proprioception and muscular activity was performed. By using synchronous surface electromyography and 3-dimensional motion analysis three standard ballet positions without and with applied tape were performed. Muscular activities of pronator muscles (peroneus longus) and supinator muscles (tibialis posterior) were recorded. EMG measurements showed significant differences between patients with stable or unstable ankles and painful or pain-free feet. Applying tape led to significant changes of muscle activities in height and antagonist reflex patterns. These changes were highest in dancers with unstable ankle joints and metatarsalgia.

Adult↗
PubMed1993

[The status of the direct magnifying x-ray technique in orthopedics].

22 patients suffering from different orthopaedic disease patterns were x-rayed with direct x-ray magnification with focus diameters between 0.012 and 0.100 mm. This yielded improved resolution of detail structures, especially in tumours and aseptic bone necroses. Due to the relatively low efficiency of the x-ray tube (conditioned by the physics of the x-ray equipment), however, exposure times of several seconds were required, and the voltage had to be higher than in conventional x-ray procedure. This resulted in lack of sharpness due to movement and to a loss in contrast. Hence, the clinical use of focus diameters below 0.1 mm does not seem to be meaningful.

Bone Neoplasms↗
PubMed1992

[Use of lasers in arthroscopy].

Arthroscopic surgery has become a routine procedure, thanks to the availability of excellent video systems and the development of new and efficient instruments. Since early 1980 several groups have been developing arthroscopic laser surgery. Laser technology is ideal for use in endoscopic surgery because lasers are potentially extremely small but nevertheless powerful tools with many advantages. Initially, attempts were made to modify CO2 lasers an Nd: YAG lasers for arthroscopic surgery, since these devices were readily available in many hospitals, but they proved unsuitable for arthroscopy. Clear definition of the desired goals and much experimentation eventually led to the development of three suitable systems: excimer, holmium: YAG and erbium: YAG lasers. After extensive investigation in the past few years, many groups have, for technical reasons, now opted for the holmium: YAG-laser as the best compromise. Lasers are used in arthroscopy not only to divide tissue but also to smoothen cartilage, for hemostasis, for percutaneous lumbar and cervical disc surgery, for photodynamic therapy, for tumor therapy and in diagnosis. The threshold to clinical practice in orthopedic laser surgery has now been crossed. Lasers must now show, in prospective clinical studies, that their theoretical advantages are matched in practice.

Animals↗
PubMed1992

Biterminal tenotomy for the treatment of congenital muscular torticollis. Long-term results.

Fifty-five patients who, in a twenty-eight-year period, had been managed with a biterminal open release because of congenital muscular torticollis, were re-examined at an average of fifteen years and a minimum of five years after the operation. Forty-eight patients reported no functional or cosmetic impairment. Palpable soft-tissue strands remained in twenty-nine patients, but bending toward the untreated side was limited more than 10 degrees in only one patient. The rate of recurrence was 2 per cent. Facial asymmetry improved or resolved in more than one-half of the patients. We recommend that biterminal release be performed at the age of three to five years in all patients who do not respond to non-operative treatment.

Adolescent↗
PubMed1991

[Complex movement analysis: dynamic study of the effect of a tape bandage on pronation in high-jumping with three-dimensional movement analysis and electromyography].

Overuse syndromes in the lower extremity are a frequent problem in athletics, especially in jumping events. Athletes notice a comfortable support by using ankle taping without restriction of their performance. Up to now no objective data is available about efficiency of taping against overpronation which is frequent in high jumping. In high jumping without boots little difference of pronation between taped and untaped take off leg was found. In contrast in jumping with spikes boots a marked pronation during take off was found, which was reduced by ankle taping with a reduction of maximum medial malleolar medialisation by 77%, reduction of pronation time by 33% and time of maximum pronation by 8.2% in the take off leg. Surface electromyography showed an increased activity of M. peroneus longus by 30.7% as a plantarflector and pronator muscle with ankle taping. Activity of other jump supporting muscles of the lower extremity was little influenced.

Adolescent↗
PubMed1991

[The significance of the activity score in evaluating knee ligament reconstructions].

In a follow-up study of 156 patients after knee ligament reconstruction for chronic instability, the results of subjective Lysholm score grading and of Tegner activity grading were compared. The postoperative Lysholm score averaged 85 +/- 13.2 points, the activity scores 6.9 +/- 0.9 points prior to instability, 1.7 +/- 0.9 points preoperatively and 5.9 +/- 1.2 points postoperatively. 89 patients reached their preinjury activity level, the average improvement through surgery was 4.2 +/- 1.6 points. Non-active patients regularly returned to their original activity-level, competitive athletes were less likely to regain their previous activity. The subjective results of athletes and non-athletes showed no significant differences. The postoperative activity level clearly correlated to subjective grading by the patient. For scoring results after knee ligament surgery, we use the subjective Lysholm score and an activity score based on average German sports activities.

Activities of Daily Living↗
PubMedDate not supplied

[Use of lasers in orthopedic surgery--a mutagenesis risk?].

Since ten years different laser systems have been used in arthroscopic procedures and percutaneous laser disc decompression. A potential mutagenic risk has not been excluded yet. From photobiology it is known that light in the UV-range is the main source of mutations. Therefore the aim of our study was to determine the mutagenic risk of laser systems at UV-wavelengths. The BALB/3T3 cell line was irradiated at the Excimer wavelengths 248 nm and 308 nm. Transformation rates were compared with non-irradiated cells and the effect of 1 Gy-Roentgen irradiation. Pulse energy, frequency and irradiation time were varied over a broad range. The effect of double irradiation was also examined. For 308 nm no significant transformation rate was found (p < 0.18). In contrast 248 nm showed a highly significant transformation rate (p < 10(-9). Transformation rate after Roentgen irradiation exceeded that of the negative control about two orders. While a certain mutagenic risk exists for 248 nm application of the wavelength 308 nm seems harmless. Our data therefore represent an essential contribution to long term laser safety both for the physician and his patient.

3T3 Cells↗