Biomedical subjects

Andreas Korge

Publications and source records attributed to Andreas Korge.

6 recordsLinked to original sources

PubMed2007

Total lumbar disc replacement in athletes: clinical results, return to sport and athletic performance.

Despite the increasing popularity of total lumbar disc replacement (TDR) in predominantly young and active patients, no previous study has addressed possibilities, limitations and potential risks regarding athletic performance following TDR. Mechanical concerns remain and the implant's resilience as regards its load-bearing capacity during sporting activities is unknown. Thirty-nine athletic patients fulfilled the inclusion criteria for this study. These patients participated in a large variety of different types of sport. Significant and lasting pain-relief was attained following TDR with a mean follow-up of 26.3 months (range 9-50.7 months; FU rate 97.4%). Sporting activity was resumed within the first 3 months (38.5%) to 6 months (30.7%) with peak performance being reached after 5.2 months. Thirty-seven patients (94.9%) achieved resumption of sporting activity. Athletic performance improved significantly in 33 patients (84.6%). Minor subsidence was observed in 13 patients (30%) within the first 3 months with no further implant migration thereafter in 12 patients. Participation in all types of sport recorded in this study was accessible for a high rate of patients up to the level of professional athletes as well as those participating in extreme sports. Preoperative participation in sport proved to be a strong positive predictor for highly satisfactory postoperative outcome following TDR. In a selected group of patients, however, preoperative inability to participate in sporting activities did not impair postoperative physical activity. Due to the young age of the patients and significant load increase exerted during athletic activities, persisting concerns regarding the future behaviour of the implant remain and will require longer follow-up, modified investigation techniques and larger patient cohorts.

Adult↗

PubMed2006

Heterotopic ossification in total cervical artificial disc replacement.

STUDY DESIGN: Prospective clinical study enrolled in 2 centers (Munich and Liberec) as part of a prospective European multicenter study with ProDisc C (Synthes Inc., Paoli, PA). OBJECTIVES: The first goal of the study was to evaluate the rate of heterotopic ossifications identified with plain radiograph following total cervical disc replacement (TCDR). The second goal was to show whether segmental motion can be preserved, and whether TCDR can provide improvement of the patient's ability to perform activities of daily living as well as a decrease of pain. SUMMARY OF BACKGROUND DATA: Only a few reports about the radiologic outcome after TCDR are published so far. Heterotopic ossification is a well-known phenomenon after total hip arthroplasty. The rate of heterotopic ossification following TCDR is unclear. METHODS: The radiographs of 54 patients (in total, 77 implanted prostheses) were analyzed 1 year after TCDR with a ProDisc C prosthesis. We classified the heterotopic ossification in 5 grades according to a recently published classification system for lumbar total disc replacement. For clinical parameters, the visual analog scale and the Neck Disability Index were evaluated preoperatively and 1 year postoperatively. The Student t test and Wilcoxon test were used for statistical analysis. RESULTS: In 26 treated segments (33.8%), no heterotopic ossification was detectable. Grade 1 ossifications were present in 6 levels (7.8%). A total of 30 segments (39.0%) showed grade 2 ossifications. Heterotopic ossifications that led to restrictions of the range of motion were present in 8 cases (10.4%). One year postoperatively, 7 cases (9.1%) had a spontaneous fusion of the treated segment. The clinical parameters improved significantly and were similar to previous reports about TCDR. CONCLUSIONS: Only 33.8% of the patients did not show any signs of heterotopic ossification, and the rate of spontaneous fusion after TCDR 1 year after surgery was unexpectedly high. There were 49.4% of the patients with grade 2-3 ossification, which lets us suspect an even higher rate of spontaneous fusion after long-term follow-ups. Motion preservation after TCDR is only guaranteed if spontaneous fusion can be prevented. Thus, mobility of the implanted segments needs to be further studied.

Cervical Vertebrae↗

PubMed2006

Clinical results of total lumbar disc replacement with ProDisc II: three-year results for different indications.

STUDY DESIGN: Prospective study analyzing midterm clinical results of total lumbar disc replacement (ProDisc II) for different indications. OBJECTIVES: To assess functional outcome after total lumbar disc replacement (TDR) treated for varying indications. SUMMARY OF BACKGROUND DATA: Despite its frequent use and increasing popularity, indications and contraindications for TDR have not been defined precisely at this stage and remain a matter of debate, leading to disc replacement procedures in a variety of pathologies that have not yet been evaluated and compared separately. METHODS: Patients meeting inclusion criteria were evaluated prospectively according to Visual Analogue Scale (VAS), Oswestry Questionnaire, SF-36, and numerous clinical parameters. Indications included degenerative disc disease (DDD), DDD with accompanying soft disc herniation (nucleus pulposus prolapse, NPP), osteochondrosis following previous discectomy, and DDD with presence of Modic changes. Postoperative improvement was recorded and analyzed for influence of preoperative diagnosis. RESULTS: Overall, 92 patients from four groups with a mean follow-up of 34.2 months (minimum, 24 months) achieved significant and maintained improvement from preoperative levels (P < 0001). Patients with DDD + NPP achieved results significantly better than patients from the other groups (P < 0.05). Presence of Modic changes or previous discectomy did not influence outcome negatively. Improvement was achieved for both monosegmental and bisegmental disc replacements (P < 0.05), nevertheless with significantly inferior results for bisegmental interventions at 12- and 24-month follow-up and considerably higher complication rate. While older patients were still highly satisfied with postoperative outcome, better functional outcome was observed in younger patients. CONCLUSION: Present data suggest beneficial clinical results of TDR for treatment of DDD in a highly selected group of patients. Better functional outcome was obtained in younger patients under 40 years of age and patients with degenerative disc disease in association with disc herniation. Multilevel disc replacement had significantly higher complication rate and inferior outcome. Results are significantly dependent on preoperative diagnosis and patient selection, number of replaced segments, and age of the patient at the time of operation. Because of significantly varying outcomes, indications for disc replacement must be defined precisely.

Adult↗

PubMed2005

An immunohistochemical study of the tissue bridging adult spondylolytic defects--the presence and significance of fibrocartilaginous entheses.

UNLABELLED: Introduction Spondylolytic spondylolisthesis is an osseous discontinuity of the vertebral arch that predominantly affects the fifth lumbar vertebra. Biomechanical factors are closely related to the condition. An immunohistochemical investigation of lysis-zone tissue obtained from patients with isthmic spondylolisthesis was performed to determine the molecular composition of the lysis-zone tissue and enable interpretation of the mechanical demands to which the tissue is subject. METHODS: During surgery, the tissue filling the spondylytic defects was removed from 13 patients. Twelve spondylolistheses were at the L5/S1 level with slippage being less than Meyerding grade II. Samples were methanol fixed, decalcified and cryosectioned. Sections were labelled with a panel of monoclonal antibodies directed against collagens, glycosaminoglycans and proteoglycans. RESULTS: The lysis-zone tissue had an ordered collagenous structure with distinct fibrocartilaginous entheses at both ends. Typically, these had zones of calcified and uncalcified fibrocartilage labelling strongly for type II collagen and aggrecan. Labelling was also detected around bony spurs that extended from the enthesis into the lysis-zone. The entheses also labelled for types I, III and VI collagens, chondroitin four and six sulfate, keratan and dermatan sulfate, link protein, versican and tenascin. CONCLUSIONS: Although the gap filled by the lysis tissue is a pathological feature, the tissue itself has hallmarks of a normal ligament-i.e. fibrocartilaginous entheses at either end of an ordered collagenous fibre structure. The fibrocartilage is believed to dissipate stress concentration at the hard/soft tissue boundary. The widespread occurrence of molecules typical of cartilage in the attachment of the lysis tissue, suggests that compressive and shear forces are present to which the enthesis is adapted, in addition to the expected tensile forces across the spondylolysis. Such a combination of tensile, shear and compressive forces must operate whenever there is any opening or closing of the spondylolytic gap.

Adult↗

PubMed2003

Immunohistochemical analysis of the extracellular matrix in the posterior capsule of the zygapophysial joints in patients with degenerative L4-5 motion segment instability.

OBJECT: Although the hypertrophied shape of the zygapophysial joints in degenerative instability of the lumbar spine is well known, its underlying pathophysiological mechanism is unclear. The authors sought to provide evidence that there is increased fibrocartilaginous metaplasia in the posterior joint capsule resulting from greater mechanical loading; the authors suggest that these capsular changes are central to understanding the altered joint shape. METHODS: The LA-5 posterior articular complex was removed in 14 patients undergoing fusion for degenerative instability. After methanol-assisted fixation, cryosections were immunolabeled for a wide range of extracellular matrix molecules. These were collagens (Types I, II, III, V, and VI), glycosaminoglycans (chondroitin 4 and 6 sulfates; dermatan- and keratan-sulfate), and proteoglycans (versican, tenascin, aggrecan, and its associated link protein). The grade of degeneration of the articular complexes was assessed radiologically and histologically. CONCLUSIONS: The results of this study provide molecular evidence for an altered loading history on the joint capsule. The pronounced loss of intervertebral disc height that occurred in all patients with severe degeneration of the lumbar motion segment promotes an increased range of axial rotation that places the posterior capsule under greater mechanical load. Compared with normal joints studied previously, the posterior capsules involved in these degenerative joint complexes were hypertrophied and fibrocartilaginous throughout. Cartilaginous metaplasia was especially pronounced at the attachment sites (entheses) where the fibrocartilage now extended beyond the original level of the joint space, and capped the osseous spurs arising from these attachment sites.

Adult↗

PubMed2002

Non-fusion technology in degenerative lumbar spinal disorders: facts, questions, challenges.

Although surgical fusion of the painful degenerating functional spinal unit (FSU) of the lumbar spine has always been a matter of debate, it has become a gold-standard procedure for all cases that lack an alternative treatment. However, a detailed and honest review of the clinical data reveals a considerable number of undesired side effects, complications and poor outcomes. The continuous search for alternative surgical treatment modalities has led to the development of numerous ideas for surgical reconstruction of the anterior and/or posterior column. The term "spine arthroplasty" summarises all procedures that have the goal of restoring function. This article describes the principles of the most current surgical techniques and implants, it points out potential challenges and poses a number of questions that need evidence-based answers before the incorporation of these innovations into surgical routine can be justified.

Humans↗