Biomedical subjects

C Hopf

Publications and source records attributed to C Hopf.

At least 37 records · Page 2Linked to original sources

PubMed1997

Primary stable anterior instrumentation or dorsoventral spondylodesis in spondylodiscitis? Results of a comparative study.

The operative results of 23 patients with a specific or unspecific spondylodiscitis were documented over 2 years after the focus of the inflammation had been eradicated, bone chip had been interposed and a CDH instrumentation had been performed by an anterior approach only. These outcomes were compared with the results of 32 patients in whom the focus had been removed and the defect had been filled with bone graft from an anterior approach, followed by stabilisation with CD instrumentation through an additional dorsal approach. In the cases where CDH instrumentation was applied, the range of fusion averaged 1.3 segments. This was clearly less extensive than in dorsoventral stabilisation, in which on average 3.5 segments were fused. In 47 of 55 cases mobilisation was achieved without orthesis. Eight months after the operations bony fusion could be observed radiologically in all patients. The mean preoperative kyphotic angle of the affected segments was 14.4 degrees, compared to 4 degrees after the operation. The mean loss of reposition was measured to be about 2.7 degrees in both groups. Average operation time and blood loss were about 50% higher in the patients treated dorsoventrally. We conclude that even in the case of florid spondylodiscitis, a short-range anterior fusion of the affected spinal segment may be performed by use of a stable-angle implant without an increased risk of infection-related loosening.

Bone Transplantation↗

PubMed1997

[Fractures after total knee joint endoprosthesis. Results of treatment with various stabilizing methods].

In 20 patients with a fracture of femur or tibia 5.2 years after arthroplasty of knee the results of the operative treatment are presented. The results show that especially bone damaging diseases as rheumatoid arthritis, osteoporosis and the loosening of the endoprosthesis are favorable for the fracture during the follow-up. The conclusion of the investigation shows that in younger patients the external fixation by plates and screws is the preferential treatment, in elderly people or comminuted fracture an internal fixation, also in combination with an additional osteosynthesis, allows a fast mobilization. The number of observed complications is higher than in primary knee arthroplasty, the full weight bearing 1st delayed. The rate of further operations and unsatisfactory results is also higher being affected by the high mean age of the operated patients (73.4 years). The possible use of a total femur implant must be discussed critically because only an individual production can avoid further damage of the parts of the joint that were not concerned by the fracture.

Aged↗

PubMed1997

[Extracorporeal shockwave treatment of delayed bone healing. A critical assessment].

Since the late 1980s, experiments have been performed to influence physiologic and disturbed healing of bone. However, the mainly negative results of animal studies, cannot be applied to the human nonunion situation as long as there is no adequate animal pseudarthrosis model. Prospective clinical studies in various centres have resulted in success rates of more than 50%, although the majority of patients had been treated repeatedly and ineffectively with the gold standard of re-osteosynthesis and grafting. Since the mechanisms are not yet understood, only such desperate conditions are an indication for the application of high-energy extracorporal shock waves.

Adolescent↗

PubMed1997

[Extracorporeal shock-wave therapy. Experimental basis, clinical application].

The purpose of our studies was to investigate experimentally the dose-dependent effects of extracorporeal shock waves on tendon and bone and to unveil therapeutic possibilities in tendinopathies and pseudarthroses. In animal experiments, both positive and negative influences were exerted by shock waves, depending on the initial situation and on the power of the applied shock waves. In prospective clinical trials positive effects were found in the treatment of persistent tennis elbow, plantar fasciitis, calcifying tendinitis, and pseudarthrosis. Our data show that extracorporeal shock waves may provide analgesic, resorptive and osteo-inductive reactions with nearly no side effects. However, the high cost of apparatus and staff prevents a routine application. Extracorporeal shock waves thus remain a last alternative before the indication is made for an operative procedure.

Achilles Tendon↗

PubMed1997

Heparin inhibits acetylcholine receptor aggregation at two distinct steps in the agrin-induced pathway.

Muscle cells depend on motoneurons for the initiation of postsynaptic differentiation during early development of the neuromuscular junction. Motoneurons secrete specific isoforms of the extracellular matrix protein agrin which trigger the aggregation of acetylcholine receptors (AChRs) on the muscle surface. Both motoneuron- and agrin-induced AChR aggregation are inhibited by heparin. Here we show that this inhibition is due to two separate and distinguishable mechanisms. At high concentrations, heparin directly binds to agrin isoforms which contain the peptide KSRK, resulting in a virtually complete inhibition of AChR clustering. Heparin and other polyanions do not bind to agrin splicing variants without KSRK insert. Isoforms containing or lacking the KSRK insert have a high potency to induce AChR aggregation in the presence of an activating eight-amino-acid insert. This activity is inhibited by low concentrations of heparin even in the absence of any binding of heparin to agrin. Therefore, this second type of inhibition is due to the interaction of heparin with a downstream component of the agrin-induced clustering pathway. Binding of heparin to this yet unidentified component substantially decreases, but does not completely abolish AChR aggregation. The inhibition is particularly strong on myotubes which have not completely matured in culture.

Agrin↗

PubMed1996

Agrin binding to alpha-dystroglycan. Domains of agrin necessary to induce acetylcholine receptor clustering are overlapping but not identical to the alpha-dystroglycan-binding region.

The synaptic basal membrane protein agrin initiates the aggregation of acetylcholine receptors at the postsynaptic membrane of the developing neuromuscular junction. Recently, alpha-dystroglycan was found to be a major agrin-binding protein on the muscle cell surface and was therefore considered a candidate agrin receptor. Employing different truncation fragments of agrin, we determined regions of the protein involved in binding to alpha-dystroglycan and to heparin, an inhibitor of alpha-dystroglycan binding. Deletion of a 15-kDa fragment from the C terminus of agrin had no effect on its binding to alpha-dystroglycan from rabbit muscle membranes, even though this deletion completely abolishes its acetylcholine receptor aggregating activity. Conversely, deletion of a central region does not affect agrin's clustering activity, but reduced its affinity for alpha-dystroglycan. Combination of these two deletions resulted in a fragment of approximately 35 kDa that weakly bound to alpha-dystroglycan, but displayed no clustering activity. All of these fragments bound to heparin with high affinity. Thus, alpha-dystroglycan does not show the binding specificity expected for an agrin receptor. Our data suggest the existence of an additional component on the muscle cell surface that generates the observed ligand specificity.

Agrin↗

PubMed1996

Low-energy extracorporeal shock wave therapy for painful heel: a prospective controlled single-blind study.

The aim of this prospective single-blind pilot study was to explore the pain-alleviating effect of low-energy extracorporeal shock wave therapy (ESWT) in painful heel associated with inferior calcaneal spurs. Thirty patients who suffered from persistent symptoms for more than 12 months qualified for low-energy ESWT and were assigned at random to two groups, real or simulated ESWT. Before beginning the treatment, any other therapy was stopped for a period of 6 weeks. The shock waves were applied by a experimental device allowing exact localization through an integrated fluoroscopy unit. Patients were treated three times at weekly intervals. Each time 1000 impulses of 0.06 mJ/mm2 were given around the heel spur. Follow-ups were done after 3, 6, 12 and 24 weeks. Patients of the placebo group who did not improve at the 6-week follow-up were then offered ESWT therapy and were checked at 3, 6, 12 and 24 weeks after the last treatment. Whereas we noticed no significant differences between the groups before ESWT, there was a significant alleviation of pain and improvement of function at all follow-ups in the treatment group.

Adult↗

PubMed1996

Low-energy extracorporal shock wave therapy for persistent tennis elbow.

Fifty patients who suffered from persistent tennis elbow for more than 12 months, and were referred for surgical treatment, were assigned at random to 2 groups of low-energy extracorporal shock wave therapy. Group I received a total of 3000 impulses of 0.08 mJ/mm2; group II (controls) 30 impulses of 0.08 mJ/mm2. Follow up was after 3 and 12 weeks. We found no significant differences between the 2 groups before treatment, there was but significant relief of pain and improvement of function in group I with good or excellent outcome in 56% at the last evaluation.

Adult↗

PubMed1996

[Treatment concepts of femoral fractures after total endoprosthetic replacement of the hip or knee joint: intra- or extramedullary stabilization?].

A comparison between intramedullary (n = 13) and extramedullary (n = 37) stabilization was performed in 50 patients (mean age 67.4 years) after fractures of the femoral shaft following knee or hip arthroplasty. Fracture of the femoral shaft (mean 5.5 years after the implantation) is observed especially often in patients with osteoporosis, loosening of the prosthesis, and rheumatoid arthritis. The ratio between cemented and uncemented endoprosthesis was 4:1. The investigation shows that extramedullary stabilization by means of plates and screws is the preferred treatment for younger patients and in the case of distal fractures, while in older people intramedullary fixation in combination with an additional osteosynthesis allows early mobilization. The number of complications observed is higher than with primary arthroplasty. The frequency of further operations, postoperative fractures and unsatisfactory results is significantly higher than in primary hip and knee surgery or uncomplicated fracture of the femur.

Adult↗

PubMed1995

Proliferation enhancement by spontaneous multiplication of chromosome 7 in rheumatic synovial cells in vitro.

Mosaic trisomy of chromosome 7 is known to occur in a variety of non-neoplastic hyperproliferative disorders. In long-term cell cultures established from rheumatic synovium with mosaic trisomy 7, we observed a continuous increase in the proportion of cells with trisomy 7 to over 50% by the 10th in vitro passage. Simultaneous in situ hybridization with a repetitive chromosome-7-specific DNA probe and fluorescent Ki-67 labelling showed a strong correlation between trisomy 7 and an elevated proliferation index in cultured rheumatic synovial cells. Moreover, we observed a fraction of rapidly proliferating cells with up to eight copies of chromosome 7 as the sole cytogenetic change. Frequent somatic pairing of centromeres of two chromosomes 7 in interphase nuclei suggests either atypical non-disjunction with a persisting centromere or selective endoreduplication of chromosome 7.

Arthritis, Rheumatoid↗

PubMed1995

Clinical efficacy of pedicle instrumentation and posterolateral fusion in the symptomatic degenerative lumbar spine.

Eighty-five patients with degenerative lumbar spine disease and radiologic evidence of instability, all older than 50 years (mean age 63.4 years), underwent transpedicular lumbar CD-spondylodesis and posterolateral fusion between 1987 and 1992; 30 of them (mean age 60.8 years) had posterior lumbar interbody fusion (PLIF) additionally. The patients were followed up for a mean period of 32 months. Of these patients, 86% improved with respect to their pain symptoms, but only 46% showed a good to excellent overall result. Patients with fair and poor outcomes had had significantly more operations on the lumbar spine (P < 0.001), had a greater extent of preoperative lumbar kyphosis (P < 0.05), had a larger preoperative motor weakness (P < 0.05), and had less vertebral slips (P < 0.01) than patients with good to excellent outcomes. Patients treated with transpedicular spondylodesis plus PLIF did not make any better progress than those with transpedicular fusion alone. By the 6-month follow-up a significant difference in the clinical outcome was already apparent (P < 0.001), making an improvement of a then fair or poor result unlikely.

Aged↗

PubMed1995

Extracorporal shock wave therapy for calcifying tendinitis of the shoulder.

During the past 2 years, 40 patients referred to the authors' hospital for persistent calcifying tendinitis of the shoulder were seen on prospective followup after undergoing a single extracorporal shock wave therapy. During a single therapy session, all patients received 1500 impulses of the energy density 0.28 mJ/mm2 in plexus anesthesia. Followup examinations were done at 6 and 24 weeks. In 62.5% of the patients partial or complete disintegration of the deposit was observed. Statistical analysis showed significant improvement both of subjective and objective criteria. According to the Constant score, 60% of the patients reached normal values, and 72.5% of the patients had no or only occasional discomfort. Only 6 patients (15%) reported no improvement at the 24-week followup.

Anesthesia, Conduction↗

PubMed1994

Metastatic instability at the proximal end of the femur. Comparison of endoprosthetic replacement and plate osteosynthesis.

A retrospective study was performed of the surgical treatment of metastatic lesions of the proximal femur in 50 patients. In 25 consecutive cases a megaprosthesis was implanted; compound plate osteosynthesis was performed in another 25 consecutive patients. Indications for surgical treatment were pathological fractures or, for prophylactic treatment, lesions of the femoral cortex exceeding 2.5 cm in diameter or affecting half the diameter of the bone or more. In all patients capable of walking preoperatively mobility was regained. Immediate full weight-bearing stability was obtained in all patients. Group analysis showed that the functional rating of the hip joint was unchanged, i.e., good or excellent, in all patients with compound osteosynthesis, compared to only 68% in the endoprosthesis group. Pain relief was excellent or good in 84% and 88% respectively. Dislocation of the tumor prosthesis occurred in 3 patients. Closed reduction was possible in 2 cases. Local recurrence was higher in the patients undergoing plate osteosynthesis, as was the frequency of tumor-related implant failure. Postoperative survival averaged 14.7 months and 12.1 months respectively.

Adult↗

PubMed1994

Operative management of epidural tumors of the spine.

Seventy-two patients with neoplastic involvement of the vertebral column were operated on between 1986 and 1991. In the course of 79 operations anterior decompression and stabilization alone were performed in 3 cases, while ventrodorsal spondylodesis was carried out in 10 individuals. The remainder of the patients underwent exclusively dorsal decompression and stabilization, mainly with the Cotrel-Dubousset instrumentation (CDI). No external spinal support was required following posterior fixation by CDI alone or in combination with ventral spondylodesis. Forty patients suffered from neurological deficits preoperatively, 20 of them being unable to walk, in most cases owing to severe vertebral collapse. Neurologic symptoms improved in 18 patients postoperatively. Median postoperative survival time averaged 11.5 months. In palliative surgery of the spine, posterior decompression and fixation using CDI permit most patients to retain ambulation without requiring external orthotics. The rate of postoperative complications is reduced by the introduction of CDI.

Adult↗

PubMed1994

Prognostic criteria of discogenic paresis.

This discourse is aimed at elucidating prognostic criteria for the assessment of the course of a paresis in the case of lumbar disc herniation. Fourhundred and fifty patients were examined who had been operated on for lumbar disc herniation at the Orthopaedic University Clinic Mainz between 1986 and 1991. Of these, 240 showed radicular paralytic symptoms. They were examined prior to the operation, immediately afterwards and 1 year after the operation. The influence of the degree of intensity of the paresis, the time elapsed since the occurrence and other factors like nerve root affected, intraoperative findings, age, sex and weight of the patient were registered. It is obvious that the degree of intensity of a paresis is a good prognostic criterion for the assessment of the postoperative course. A paresis classified as grade III or IV receded in more than 70% of the cases within 6 months. For a paresis of grade II, the recovery rate was 40%. In the case of a total paresis, no complete neurological recovery was registered. The period of time which had elapsed since the occurrence of the paresis, the weight of the patient, the nerve root affected and other factors did not show any significant influence. As a criterion for an emergency or postponed operation on a herniated disc, the duration of paralytic symptoms should therefore be attributed less importance than the progression.

Adult↗

PubMed1994

[Significance of the intervertebral disk in failed reduction of surgically stabilized fractures of the truncal spine].

In 112 patients with a traumatic fracture of the thoraco-lumbar spine operatively treated with different dorsal stabilization techniques from 1983 to 1988, the frontal and sagittal planes of the spine were analyzed over a follow-up period of 5 years. In 14 cases Harrington instrumentation was used, in 81 cases, transpedicular plates, and in 17 cases, a fixateur interne. With regard to the frontal plane the overall loss of correction was 2.3 degrees: with Harrington stabilization 0.7 degrees, with fixateur interne 2.6 degrees, and with plate fixation 3.7 degrees. In the sagittal plane the height of the damaged spinal segment and the kyphotic angulation were determined. The mean height loss after operative repositioning was 12%. With Harrington stabilization it was 16%, with plate fixation 12%, and with fixateur interne 9%. Kyphosis of 9.6 degrees was determined before surgery, and 0.9 degrees after. The angle subsequently deteriorated, reaching 12.6 degrees by the end of 5 years. The loss of correction was 9.3 degrees in the fixateur interne group, 10.9 degrees in the Harrington stabilization group, and 15 degrees in patients in whom plate fixation had been performed. The cause of deterioration was destruction of the invertebral disc in 66% of cases, and angulation of the fractured vertebral body in only 33%. Only in the first 2 years after operation was loss of reposition in the vertebral body observed. In conclusion, stabilization should be complemented by removal of the damaged adjacent disc and intercorporeal autogenous bone grafting from the dorsal or ventral approach.

Adolescent↗

PubMed1994

[Natural course in idiopathic scoliosis].

We still do not know enough about the natural course of untreated idiopathic scoliosis although more knowledge would be desirable from the point of view of deciding on adequate conservative treatment or operative therapy. We present the natural course of 110 cases of marked scoliosis and 135 cases of slight, untreated scoliosis with respect to age, sex and localization of the curve. The results are compared to those of other authors.

Adolescent↗

PubMed1993

The operative treatment of spinal deformities in MMC.

The results of the operative treatment of scoliosis in 12 patients with MMC and in two patients with associated severe kyphosis are presented. In scoliosis only multi-segmental methods combined with ventral procedures allow a postoperative care without brace or cast. The angle before and after operation with the CDI or CDI/VDS procedures averaged 80.3 degrees and 38.2 degrees respectively (mean corrections of 41.5 degrees and 51.6%). The results show that patients with scoliosis with MMC had a approximately 30% greater preoperative angle than patients with idiopathic scoliosis. An early operation (in progressive curves with more than 30 degrees) may reduce the number and severity of complications.

Adolescent↗