Biomedical subjects

Klaus John Schnake

Publications and source records attributed to Klaus John Schnake.

3 recordsLinked to original sources

PubMed2006

Mechanical concepts for disc regeneration.

Different strategies exist to treat intervertebral disc degeneration. Biological attempts to regenerate the disc are promising. However, degeneration of the disc is always accompanied by alterations of disc height, intradiscal pressure, load distribution, and motion patterns, respectively. Since those preconditions are independent factors for disc degeneration, it is unlikely that regeneration may occur without firstly restoring the physiological status of the affected spinal segment. In vitro and in vivo animal studies demonstrate that disc distraction normalizes intradiscal height and pressure. Furthermore, histological and radiological examinations provided some evidence for regenerative processes in the disc. Only dynamic stabilization systems currently offer the potential of a mechanical approach to intervertebral disc regeneration. Dynamic stabilization systems either using pedicle screws or with an interspinous device, demonstrate restabilization of spinal segments and reduction of intradiscal pressure. Clinical reports of patients with degenerative disc disease who underwent dynamic stabilization are promising. However, there is no evidence that those implants will lead to disc regeneration. Future treatment concepts should combine intradiscal cell based therapy together with dynamic restoration of the affected spinal segment.

Biomechanical Phenomena↗

PubMed2006

Dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis.

STUDY DESIGN: Prospective clinical study. OBJECTIVE: To test whether elastic stabilization with the Dynesys system (Zimmer Spine, Minneapolis, MN) provides enough stability to prevent further progression of spondylolisthesis as well as instability after decompression for spinal stenosis with degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: In spinal stenosis with degenerative spondylolisthesis, decompression and fusion is widely recommended. However, patients have donor site pain. In 1994, a dynamic transpedicular system (Dynesys) was introduced to the market, stating that stabilization is possible without bone grafting. METHODS: A total of 26 patients (mean age 71 years) with lumbar spinal stenosis and degenerative spondylolisthesis underwent interlaminar decompression and dynamic stabilization with the Dynesys system. Minimum follow-up was 2 years. Operative data, clinical outcome, and plain and flexion/extension radiographs were obtained and compared to preoperative and postoperative data. RESULTS: Mean leg pain decreased significantly (P < 0.01), and mean walking distance improved significantly to more than 1000 m (P < 0.01). There were 5 patients (21%) who still had some claudication. A total of 21 patients (87.5%) would undergo the same procedure again. Radiographically, no significant progression of spondylolisthesis could be detected. The implant failure rate was 17%, and none of them were clinically symptomatic. CONCLUSIONS: In elderly patients with spinal stenosis with degenerative spondylolisthesis, dynamic stabilization with the Dynesys system in addition to decompression leads to similar clinical results as seen in established protocols using decompression and fusion with pedicle screws. It maintains enough stability to prevent further progression of spondylolisthesis or instability. With the Dynesys system, no bone grafting is necessary, therefore, donor site morbidity can be avoided.

Aged↗

PubMed2002

Atlantoaxial instability in Dyggve-Melchior-Clausen syndrome. Case report and review of the literature.

Dyggve-Melchior-Clausen (DMC) syndrome is a very rare disease. Only 58 cases have been reported in the literature. The syndrome is probably an autosomal recessive inherited disorder, one that is characterized by mental retardation, the short-spine type of dwarfism, and skeletal abnormalities, especially of the spine, hands, and pelvis. Atlantoaxial instability-induced spinal cord compression is a serious and preventable complication. The purpose of this report is to describe the first case of DMC syndrome in which anterior transarticular atlantoaxial screw fixation was used to treat atlantoaxial instability. The authors report on a 17-year-old man with DMC syndrome and concomitant severe atlantoaxial instability. Computerized tomography scanning and magnetic resonance angiography demonstrated an irregular course of the vertebral artery (VA) at C-2, which made a posterior fixation procedure impossible. Additionally, transoral fusion was impossible because the patient was unable to open his mouth sufficiently. Therefore, the patient underwent anterior transarticular screw fixation. Follow-up examination 36 weeks after surgery showed solid fusion without implant failure. In conclusion, treatment of atlantoaxial instability in DMC syndrome must be considered. Specific care must be taken to determine the course of the VA. If posterior and transoral fusion are impossible, anterior transarticular atlantoaxial screw fixation might be the only alternative.

Adolescent↗