Biomedical subjects

P Griss

Publications and source records attributed to P Griss.

At least 37 records · Page 2Linked to original sources

PubMed2000

Loosening of a fenestrated femoral prosthesis: a case report with histomorphologic analysis.

The explanted loose stem of a trabecular cementless femoral prosthesis (Holz-Copf) was histologically analyzed revealing soft tissue 3 mm thick between the metal of the prosthesis and the cancellous bone. Direct contact between the implant and bone could not be found. Removal of the prosthesis was impossible by simple extraction so that a transfemoral approach was required. Prostheses with large fenestrations may be loose but at the same time ingrown with sufficient bone to require invasive procedures for their removal.

Arthritis↗

PubMed2000

Thoracic disc herniation: a diagnostic challenge.

An unusual case of lower thoracic disc herniation combined with shoulder pain is presented in this case report, A literature search showed that shoulder pain associated with a lower thoracic disc herniation has not yet been reported. An acromioplasty for chronic impingement syndrome was performed to relieve the patient's shoulder symptoms. An unsatisfactory outcome plus a progressive but incomplete paraplegia, prompted further investigation and this revealed a low thoracic herniation. The nucleotomy which followed afterwards lead to a rapid improvement of both the shoulder symptoms and the incomplete paraplegia. This case report shows that chronic shoulder pain may be caused or exacerbated by a thoracic disc herniation in the low thoracic spine. Therefore, prior to performing surgery for peripheral joint symptomatology, the possibility of a central sensitising trigger should be excluded by physical examination of neural tissue dynamics as well as any other necessary confirmatory investigations.

Adult↗

PubMed1999

[A scale for measuring symptoms related to degenerative diseases of the cervical spine. A reference in determining indications and evaluating surgical outcome].

A scale for measuring symptoms related to degenerative diseases of the cervical spine is presented. Twenty typical symptoms are listed, e. g., neck pain, dysesthesia, and reduced mobility. Responses are assessed via a 6-point scaling ("did not have symptom" - "had symptom and suffered very strongly".) The cervical spine scale was tested in three samples: patients having undergone cervical spine surgery (n = 70), patients with other orthopedic diagnoses (n = 104), and healthy students (n = 100). The single items of the scale were aggregated into four scores: total number of symptoms, degree of overall symptom distress, functional disability, and pain/psychological distress. Statistical analyses proved the high reliability (Cronbach's alpha = 0.85 to 0.95) and validity (content, convergent, discriminant) of all scores. The scale differs clearly between cervical spine patients, other orthopedic patients and healthy individuals, and between cervical spine patients with different subjective operative outcomes. For applied clinical purposes the cervical spine scale can be included in a quality of life profile (QL-profile); this allows for a readily understandable graphic depiction of individual patients' QL-status.

Activities of Daily Living↗

PubMed1999

Prevention of heterotopic bone formation after total hip arthroplasty: a prospective randomised study comparing postoperative radiation therapy with indomethacin medication.

Heterotopic ossification (HO) after total hip arthroplasty is known to be a major complication with an impact on the functional outcome. Efforts have been made to prevent the occurrence of HO by means of either radiation therapy or pharmacotherapy. To date, there are no data available regarding the relative benefit of radiation versus medication with non-steroidal anti-inflammatory drugs. The objective of this study was to compare single-dose 600-cGy radiation therapy with indomethacin medication for their effect on the prevention of heterotopic bone formation after total hip arthroplasty. In all, 154 patients were included in the study. All patients underwent primary total hip arthroplasty due to osteoarthritis. Patients were randomly assigned to three different therapeutic groups. (a) The radiation group received a single radiation dose of 600 cGy between the 2nd and 4th postoperative day. (b) The indomethacin group received an oral application of indomethacin 2 x 50 mg per day from the 1st to 42nd postoperative day. (c) The control group received neither radiation nor indomethacin medication. There were significant group differences (P < 0.001). A least significant difference test (LSD) revealed that the mean of the control group was significantly different from that of the radiation and indomethacin groups. The 13 patients (8.4%) classified Brooker 3 or 4 were all in the control group. Again, this effect was statistically significant (chi-square, P < 0.001). In conclusion, this study demonstrated that both radiation and indomethacin therapy are effective in the prevention of postoperative HO. The choice for either one of the treatments has to be based on availability, contraindications, side-effects, practicability, standardisation and cost. Based on these considerations together with the results of this study, we currently use postoperative radiation with 600 cGy for all patients undergoing primary total hip arthroplasty.

Administration, Oral↗

PubMed1999

Implant fixation by bone ingrowth.

The term osseointegration referred originally to an intimate contact of bone tissue with the surface of a titanium implant; the term bone ingrowth refers to bone formation within an irregular (beads, wire mesh, casting voids, cut grooves) surface of an implant. The section dealing with the historical background describes the development of macroporous, microporous, and textured surfaces with an emphasis on the evolution of porous and textured metal surfaces. The principal requirements for osseointegration and bone ingrowth are systematically reviewed as follows: i) the physiology of osseointegration and bone ingrowth, including biomaterial biocompatibility with respect to cellular and matrix response at the interface; ii) the implant surface geometry characteristics; iii) implant micromotion and fixation modes; and iv) the implant-bone interface distances. Based on current methods of bone ingrowth assessment, this article comparatively reviews and discusses the results of experimental studies with the objective of determining local and systemic factors that enhance bone ingrowth fixation.

Animals↗

PubMed1998

Biocompatibility analysis of different biomaterials in human bone marrow cell cultures.

A cell culture system for biocompatibility testing of hip implant materials is described. Human bone marrow cells have been chosen because these cells are in direct contact with the biomaterial after implantation in situ. The sensitivity of this method is evaluated for materials which are already being used as implants in humans and animal, e.g., hydroxyapatite (HA) ceramic, pure titanium, and ultra-high-molecular-weight polyethylene (UHMWPE). As indicative parameters of biocompatibility primary cell adherence, cell number, cell proliferation, production of extracellular matrix, cell vitality, and cell differentiation are described. After 2 weeks in culture, obvious differences between the biomaterials with respect to the indicative parameters could be observed. Cell numbers were greatest on the HA specimens. In the case of titanium alloys, we observed a decreased number of cells. The production of extracellular matrix was high for the HA ceramics but reduced for titanium specimens. The polymers allowed only a few adherent cells and showed no signs of extracellular matrix production. The results can be correlated astonishingly well to animal experiments and clinical experiences. Therefore, we suggest that this cell culture system seems to be a useful tool for biocompatibility testing of bone implantation materials. It also helps reduce animal experiments. With the help of flow cytophotometry, we analyzed the influence of biomaterials on large numbers of cells with respect to differentiation. There were similar populations of T cells and monocytes on all specimens tested. Extended B-cell and granulocyte populations, however, were observed with titanium and UHMWPE. Most osteocalcin-containing cells adhered to the HA ceramics.

Aged↗

PubMed1997

Recombinant and nonrecombinant factor XIII and its effect on bone ingrowth and strength of fixation.

Thirty cylindrical, commercially pure, titanium fiber, porous-coated Ti6Al4V implants were inserted press-fit into the proximal humeral portion of 30 sheep humeri to determine the systemic effect of recombinant factor XIII and placenta-derived factor XIII concentrate on bone ingrowth and strength of fixation. For both the recombinant factor XIII and the factor XIII concentrate group, the volume of bone ingrowth and the strength of fixation were higher than for the control specimens. However, the difference was only significant for the factor XIII concentrate group.

Animals↗

PubMed1997

In vitro testing of a new transpedicular stabilization technique.

The rigidity of a pedicle screw implant is a critical biomechanical variable in lumbar spinal fusions. Sufficient rigidity is required for integration of bone grafts and to promote healing. Osteopenia, stress shielding, and compensatory hypermobility have been described as consequences of excessive rigidity. Little is known about the biomechanical characteristics of "semirigid" compared to "rigid" implants. A new implant, whose rigidity can be varied by selection of different implant components, was tested in vitro under well-defined loading conditions. The three-dimensional load-displacement behavior of all lumbar vertebrae involved in or adjacent to the two-level fusion was evaluated for two fusion modifications: bilateral rigid and bilateral semirigid. Cyclic fatigue loading was subsequently carried out under realistic conditions and motion testing repeated. The rigid device reduced the motion of the L3-4 transfixed segment in the primary movement planes by 87.3% with respect to the intact spine value in flexion/extension (FE), 86.3% in lateral bending (LB), and 76.8% in axial rotation (AR). The semirigid device achieved a reduction in motion of 79.6% (FE), 82.7% (LB), and 51.7% (AR). The semirigid implant was particularly easy to insert, because no bending of rods or plates was necessary. The implants showed no loosening or breakage after the fatigue testing. The results are compared to other available systems and the underlying biomechanics discussed.

Aged↗

PubMed1996

Effect of specimen fixation method on pullout tests of pedicle screws.

STUDY DESIGN: Experimental axial pullout tests of a new type of pedicle screw were done on cadaveric lumbar vertebrae. The manner in which specimens were secured in the testing apparatus was varied to determined influence of specimen fixation method on the maximum pedicle screw pullout force. OBJECTIVES: To determine the appropriateness of embedding (i.e., potting) spinal specimens in polymer resin (e.g., bone cement or Plastic Padding [Plastic Padding Ltd., High Wycombe, Buckinghamshire, England]) for axial pullout tests of pedicle screws. Several different specimen fixation methods were examined to make recommendations for the standardization of future experimental testing protocols. SUMMARY OF BACKGROUND DATA: Axial pullout of transpedicular screws, although not a likely clinical mode of failure, is a popular experimental testing mode for evaluating screw-bone biomechanics. A wide variety of techniques for securing a vertebral specimen to counter the axial pullout force has been reported (including the use of polymer resin) with a correspondingly wide range in the resulting axial pullout strengths. The possible influence of the specimen fixation method on pedicle screw axial pullout strength has not been addressed previously. METHODS: Axial pullout tests of pedicle screws (DDS, Plus Endoprothetik, Rotkreuz, Switzerland) from the pedicles of 21 isolated lumber vertebral bodies were done using a Model 810 MTS Universal Testing Machine (MTS Systems, Inc., Minneapolis, Minnesota). The specimens were secured in a custom-made vise fixture either as is or after the vertebral bodies were potted in Plastic Padding up to the pedicle origin. Some of the potted specimens were wrapped first in latex to prevent polymer resin intrusion, and the others were unprotected. Pullout tests were attempted on both the left and right pedicles of each specimen, and the maximum pedicle screw pullout force was recorded. Measurement of bone mineral density by means of dual energy x-ray absorptiometry, in addition to macroscopic and scanning electron microscopy histologic analyses, microradiography, and energy dispersive X-ray spectroscopy, was done post-test to assist in the interpretation of the data. RESULTS: The maximum pedicle screw pullout force was found to be dependent on both the bone mineral density and the mode of fixation of the vertebrae. Embedding in polymer resin without protection of the specimen (i.e., latex wrapping) led to several instances of well-documented polymer resin intrusion; in these specimens, mean maximum pedicle screw pullout force was significantly greater than that of specimens secured without polymer resin and that of embedded specimens for which intrusion did not occur. CONCLUSIONS: Polymer resin intrusion can have a significant effect on the biomechanical characteristics of the bone-pedicle screw interface. When polymer resins are used to secure vertebral specimens for in vitro biomechanical tests of the bone-pedicle screw interface, it is important to either prevent intrusion (e.g., with a latex wrapping) or document post-test (e.g., through the methods described in this article) that intrusion did not occur for the specimens included in the analysis.

Aged↗

PubMed1996

[Depressivity and successful outcome of spinal surgery].

INTRODUCTION: The relationship between depression and the outcome of low back surgery was investigated. Data analysis was based on two assumptions: (1) Presurgical assessments of depression are correlated with the outcome of surgery, and, therefore, depression can be interpreted as a risk factor for surgical failure. (2) Postsurgical assessments of depression are correlated with the outcome of surgery, and therefore, depression can be interpreted as a response to treatment failure. METHODS: The sample was made up of 78 patients who had undergone lumbar nucleotomy and 132 patients with lumbar spondylodesis. Treatment outcome was evaluated 6 months after surgery in the nucleotomy group and 9 months after surgery in the spondylodesis group. Depression was assessed with the Beck Depression Inventory (BDI). Measures of treatment outcome were an objective rating system for the surgical result, functional impairment, return to work, subjective estimations of the patient, and pain intensity. RESULTS: Presurgical depression scores showed no significant relationship with surgical outcome in nucleotomy patients. In spondylodesis patients, however, there was a significant negative correlation with the patients' subjective outcome ratings. Postsurgical depression scores, on the other hand, were significantly related to almost all of the outcome variables in both treatment groups. Patients with clinically relevant postsurgical depression scores were significantly more likely not to benefit sufficiently from surgery than those with clinically not relevant depression scores. DISCUSSION: Our findings favour assumption 2 over assumption. 1. In the light of our findings, depressiveness is interpreted as a response to a non-beneficial outcome of surgery. The need for an interdisciplinary approach combining psychological counseling or treatment and physical therapy for those patients who do not benefit from surgery is discussed.

English Abstract↗

PubMed1996

Standardized evaluation of long-term results after anterior lumbar interbody fusion.

A total of 113 patients, excluding those with tumor, spondylitis, and idiopathic scoliosis, underwent anterior lumbar interbody fusion (ALIF) with autologous iliac crest graft between 1984 and 1991 at our department. The proportion of these who were failed back patients was higher than that reported in the literature. Evaluation of functional outcome was feasible in 80 patients, utilizing Oswestry and Marburg scores, which were closely intercorrelated. The overall results yielded an improvement in the Oswestry score of 35.7 percentage points. A subset of 52 patients who were evaluated twice, showed the same results at an average of 6.6 years as they did at 2.3 years following surgery. Functional results showed a weak correlation with postoperative height loss of the intervertebral space. Influencing factors for the functional result were: postoperative compensation claim, age, and obesity. Of the professional people involved, 19.4% did not return to any occupation. Patients satisfied with the result had significantly greater functional improvement. Younger patients with additional dorsal distraction prior to ALIF for reduction of severe spondylolisthesis fared better than patients with ALIF alone. The rate of complications was low and did not contribute to the postoperative functional result. On the basis of these results further prospective studies have been designed and are currently underway.

Adolescent↗

PubMed1996

[Can preoperative lung function diagnosis detect risk of intraoperative pulmonary gas exchange insufficiency in artificial hip replacement with polymethylmethacrylate cement?].

In a study of 90 patients in whom a hipjoint had been replaced for the first time using polymethylmetacrylate cement, the extent of intraoperative pulmonary gas exchange disorders was established. The effect of a preexisting disorder of lung function was determined. We checked whether an appraisal of the risk patients who are operated on can be assisted by a preoperative analysis of lung function. After preoperative diagnosis of lung function, the arterial blood gases were analysed at defined times during the operation. An intraoperative fall in the partial pressure of oxygen and an increase in carbon dioxide partial pressure in the arterial blood were found in all patients. There were pronounced interindividual differences in the extent of the disorder of pulmonary gas exchange. The degree of severity of the respective acute disorder of lung function did not show any correlation with the pre-existing disorder of pulmonary ventilation. Major hemodynamic changes were not observed. According to the present findings, a definitive statement with regard to the degree of severity of intraoperatively occurring disorders of pulmonary function cannot be expected from a preoperative analysis of pulmonary function.

Aged↗

PubMed1995

Intrathoracic dural ectasia mimicking neurofibroma and scoliosis. A case report.

Angular thoracic scoliosis combined with dural ectasia and foraminal enlargement is reported in a patient with neurofibromatosis. The dural cyst was resected through a high thoracic approach and the scoliosis dealt with by posterior spinal fixation with Modulock instrumentation. Follow up after 12 months showed no neurological deficit and no progress of the scoliosis.

Adult↗

PubMed1995

False-positive sonographic hip examinations in newborns with congenital varus deformity of the proximal femur.

In cases of congenital varus deformity of the proximal femur, the screening of hip dysplasia can lead to misinterpretations. The false-positive ultrasound result is caused by the superiorly displaced greater trochanter in hips with coxa vara, which narrows the scan window. In this paper three typical patients are presented to demonstrate that the use of additional non-standard views cannot exclude hip dysplasia in all cases. Hence, such patients with femoral abnormalities and doubtful sonographic findings should be further evaluated by arthrography or magnetic resonance imaging to rule out additional hip dysplasia.

False Positive Reactions↗

PubMed1994

Early surgical treatment for congenital vertical talus.

Congenital vertical talus is characterised by a dislocated talonavicular joint in association with an equinus position of the calcaneus. We report the results in 13 operated feet in 10 children, 3 of whom (5 feet) presented with a primary neurological disorder and 2 of whom (3 feet) suffered from arthrogryposis multiplex congenita. The other children were normal. All patients were surgically treated by a one-stage procedure which included reduction of the talonavicular joint and correction of the hindfoot equinus, trying to avoid tendon lengthenings and transfers. The age at operation was between the 3rd and the 6th month of life, with one child being operated on later due to other reasons. The patients were reviewed after an average time of 3.5 +/- 2.2 years. The clinical results were good or excellent in ten feet. Two feet showed partial or complete recurrence and one foot was slightly over-corrected. Radiographic angle measurements (talo-metatarsal I angle and talocalcaneal angle on the anteroposterior radiograph; talocalcaneal, tibiotalar and tibiocalcaneal angles on the lateral radiograph) returned to normal values in the ten good or excellent feet. Early operative treatment for congenital pes vertical talus leads to very satisfactory functional and cosmetic results, usually avoiding extensive procedures including tendon lengthenings and tendon transfers.

Achilles Tendon↗

PubMed1994

Degeneration model of the porcine lumbar motion segment: effects of various intradiscal procedures.

In an experimental study with 18 minipigs, we have tried to establish a model for the standardized evaluation of mechanical, histological and radiological phenomena of degenerative and reparative processes within the lumbar motion segment. Comparing different operative techniques revealed that the intradiscal application of hyaluronic acid into the nuclear defect is likely to enhance the regeneration process. Using the measurement of disc compliance, a semiautomatic picture analyzer and a new semiquantitative disc score could make future studies more comparable. From this basis, the intradiscal application of hyaluronic acid deserves further evaluation.

Animals↗

PubMed1993

[Evaluation of the biocompatibility of implant materials with human bone marrow cell cultures].

A cell culture biocompatibility test for implant materials is described. For the first time, the human bone marrow cells that actually come into direct contact with the implanted biomaterial can be employed. The usefulness of this method is shown for materials which have long been used in the clinical situation (hydroxyapatite, commercially pure titanium and ultra-high molecular weight polyethylene). After two weeks in culture, light- and fluorescence-microscopic and SEM studies revealed significant differences in cell growth. Maximum compatibility was shown by the hydroxyapatite specimen. In the case of commercially pure titanium we found somewhat decreased biocompatibility. Polyethylene was associated with distinct signs of cytotoxicity. These results are compatible with those of animal experiments and clinical experience. Our system would thus appear to be a useful screening test for some implantation materials, and may help reduce the need for animal tests.

Biocompatible Materials↗

PubMed1992

Synovial haemangioma of the knee joint.

Synovial haemangioma of joints are rare, but usually affect the knee joints of children and adolescents. Recurrent swelling, usually due to haemarthrosis, and intermittent pain may be present for a long time before the diagnosis is made. In this case report the common features of the condition are described, with emphasis on the occurrence of atraumatic haemarthrosis in children. The value of arthroscopy in diagnosis is discussed.

Arthroscopy↗