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Biomedical subjects

W Siebert

Publications and source records attributed to W Siebert.

At least 19 recordsLinked to original sources
PubMed2000

Macrocyclic Imidazolylboranes.

Cycles, not chains: 1-imidazolylboranes exist in polymeric form as a consequence of donor/acceptor interactions. Through the use of suitable substituents and under high dilution tetrameric and pentameric macrocyclic imidazolylboranes were synthesized. The picture shows the structure of the tetrameric 4,5-dimethylimidazolylborane (black: C, gray: B, white: N).

Journal Article↗
PubMed1999

[Percutaneous nucleotomy procedures in lumbar intervertebral disk displacement. Current status].

The discussion on the results of open spinal surgery, in particular, on complications as a result of open surgery, e.g., the so-called post-discotomy syndrome, has led to the development of less invasive methods, especially for treatment of lumbar disc prolapses. Percutaneous nucleotomy procedures are based on a variety of intradiscal diagnostic and therapy methods, such as discography, retroperitoneal spinal disc fenestration or chemonucleolysis. Since the 1970s, various methods such as mechanical percutaneous nucleotomy, automated percutaneous nucleotomy, intradiscal laser procedures and, in part, endoscopic intradiscal procedures have been developed and also used clinically. The clinical results vary from 30% good/very good results to almost 100% good/very good results, depending on the author and study. It is obvious that not many prospective randomized studies using either conservatively or surgically treated control groups have been conducted. The results of these studies on intradiscal therapy methods are often analyzed more critically and with lower success rates than the partially retrospective stuides of a single method, which often have large case numbers, but do not always meet the demanding criteria for scientific study design. To attain good results, percutaneous nucleotomy procedures can only be used to treat select cases of lumbar disc disorders according to strict indication criteria. At the present time it can be concluded that, in comparison to endoscopic und microsurgical methods, percutaneous nucleotomy procedures must be restricted to a small number of cases.

Diskectomy, Percutaneous↗
PubMed1997

[Is a preoperative evaluation program in treatment of patients with chronic lumbar syndrome useful?].

The Pre-Operative Evaluation Program (PEP) in the USA is a 1-week outpatient program for patients who have physical pathology which could be improved with surgical intervention. Patients are prepared for surgery and their hospital stay through an education process that includes educational groups, understanding of anatomy, pain and stress management, psychological testing and exercises to improve strength and spine techniques to improve functional abilities. The orthopedic clinic in Kassel developed a 14-days inpatient preoperative evaluation and education program (PEP) for potential surgical candidates with chronic back or neck pain.

Adaptation, Psychological↗
PubMed1995

High power Ho:YAG laser ablation of intervertebral discs: effects on ablation rates and temperature profile.

BACKGROUND AND OBJECTIVE: As the Ho:YAG laser gained increasing importance in recent experimental and clinical investigations, this study was performed to investigate the effect of power on ablation rates and temperature during disc ablation with a high power Ho:Yag laser under simulated clinical conditions. STUDY DESIGN/MATERIALS AND METHODS: A high power Ho:YAG laser was used to investigate the influence of increasing power from 10 to 32 Watt on ablation rate (mg) and temperature (degree C). Ablation weight was measured by a precision scale calculating the difference of the pre- and postlasing weight of the specimen after application of total energies of 1,000, 1,500, and 2,000 J. Temperatures were measured by thermoprobes, which were connected via a thermomodule to an amplifier and the signal was plotted by a computer with appropriate software. RESULTS: Whereas ablation rate rose almost linearly with total energy, increasing power above 20 W did not essentially improve ablation rate. Temperatures reached their highest values after application of a total energy of 500 J and did not rise further, whereas increasing power did not induce a rise in temperature. CONCLUSIONS: Regarding the chosen experimental setting, maximum temperatures are reached after application of 500 J, and increasing power does not induce a rise in temperature.

Animals↗
PubMed1995

Percutaneous laser discectomy of cervical discs: preliminary clinical results.

Thirty-one patients with herniated cervical discs were treated with PLDD from 1991 to 1993. In 1990, a few of these patients were treated with the Nd:YAG laser with no complications. Since 1991 we have used the holmium:YAG laser; 28 of the 31 patients experienced pain relief in a 6-week follow-up. PLDD for the cervical discs is a viable therapy.

Cervical Vertebrae↗
PubMed1989

Meniscus suture techniques: a comparative biomechanical cadaver study.

The primary stability of four common meniscus suture techniques was tested on human cadaver menisci. The test series was carried out under standard conditions (25 degrees C, 100% air humidity) using the Instron 1122 Tensometer. The tearing stress of different sutures was reproducible in different specimens dependent only on the suture technique. Knot-end techniques gave inferior results (tearing stress, 24 +/- 9 N) compared with arthroscopic techniques using a loop placed on the meniscus surface (tearing stress, 89 +/- 4 N). When an open meniscus repair is performed, a vertical stitching technique (tearing stress, 105 +/- 4 N) should be the preferred method. Horizontal sutures are weaker (tearing stress, 44 +/- 18 N).

Adult↗
PubMed1987

What is the efficacy of "soft" and "mid" lasers in therapy of tendinopathies? A double-blind study.

The efficacy of "athermic" lasers (HeNe lambda = 632.8 nm and IR diode lambda = 904 nm) in the treatment of tendinopathies was investigated in a randomized double-blind study. On 10 consecutive days, 64 patients (32 therapy, 32 placebo) were treated for 15 minutes each with a switched-on or switched-off laser under otherwise identical conditions. The extent of movement in involved joints (neutral 0 method) and rating on a pain scale for resting pain, movement pain, and pressure pain before treatment, after treatment, and 2 weeks after conclusion of therapy, as well as infrared thermography, served to check therapy. After the end of therapy, a significant reduction (P = less than 0.001) of 50% was shown for resting pain as well as reductions of 30% for movement and 30% for pressure pain. This result was identical in the therapy group and in the placebo group. There was also no indication of a different result of therapy between the therapy and placebo groups with regard to the thermographic control and the extent of movement. The breakdown of the data in terms of age, sex, and duration of disease did not provide any indications of different results for placebo or therapy. It was striking that the patients who reported sensations during or after the treatment (irrespective of whether pleasant or unpleasant) had a greater reduction of pain than the patients without sensations. This laser therapy thus did not show any effect above and beyond that in the untreated group in our double-blind clinical study.

Adolescent↗
PubMed1977

[Prophylactic procedures to prevent respiratory distress syndrome in prematures (author's transl)].

A controlled trial of antepartum glucocorticoid treatment for prevention of Respiratory Distress Syndrome (RDS) or Hyaline Membrane Syndrome (HMS) was carried out. 91 mothers, in whom premature delivery threatened between 27 and 37 weeks of gestation, were given intramuscular injections of 8-12 mg of betamethasone as well as medication inhibiting uterine activity (tocolytica and sedation) and strict bedrest to delay premature delivery for at least 24 to 48 hours. A control group of 118 mothers, who were hospitalized late and premature delivery could not be delayed, had no betamethasone treatment. There was no significant differerence in the incidence of Respiratory Distress Syndrome in premature infants in both groups, but there was a 50% lower mortality rate of Respiratory Distress Syndrome in the betamethasone treated group, due to a milder course of Respiratory Distress Syndrome Disease. Harmful effects from corticosteroids given to pregnant women prior to premature delivery were not observed in our group. The prophylactic treatment with betamethasone to diminish the mortality rate of Respiratory Distress Syndrome is therefore considered encouraging and profitable.

Betamethasone↗