Alexander C. Disch

The management of necrosis-associated and idiopathic bone-marrow oedema of the proximal femur by intravenous iloprost

Bone-marrow oedema can occur both in isolation and in association with necrosis of bone, but it has not been shown whether each respond to the same methods of treatment. We treated 16 patients with isolated oedema and 17, in which it was associated with necrosis of the proximal femur, with the prostacyclin derivative iloprost, which has been shown to be effective in the idiopathic form. The Harris hip score, the range of movement, the extent of the oedema as measured by MRI, pain on a visual analogue scale and patient satisfaction were recorded before and subsequent to treatment. In both groups, we were able to show a significant improvement (p < 0.001) in these observations during the period of follow-up indicating that iloprost will produce clinical improvement in both circumstances.

Prolonged Superficial Local Cryotherapy Attenuates Microcirculatory Impairment, Regional Inflammation, and Muscle Necrosis after Closed Soft Tissue Injury in Rats

Background Closed soft tissue injury induces progressive microvascular dysfunction and regional inflammation. The authors tested the hypothesis that adverse trauma-induced effects can be reduced by local cooling. While superficial cooling reduces swelling, pain, and cellular oxygen demand, the effects of cryotherapy on posttraumatic microcirculation are incompletely understood. Study Design Controlled laboratory study. Methods After a standardized closed soft tissue injury to the left tibial compartment, male rats were randomly subjected to percutaneous perfusion for 6 hours with 0.9% NaCL (controls; room temperature) or cold NaCL (cryotherapy; 8°C) (n = 7 per group). Uninjured rats served as shams (n = 7). Microcirculatory changes and leukocyte adherence were determined by intravital microscopy. Intramuscular pressure was measured, and invasion of granulocytes and macrophages was assessed by immunohistochemistry. Edema and tissue damage was quantified by gravimetry and decreased desmin staining. Results Closed soft tissue injury significantly decreased functional capillary density (240 ± 12 cm-1); increased microvascular permeability (0.75 ± 0.03), endothelial leukocyte adherence (995 ± 77/cm2), granulocyte (182.0 ± 25.5/mm2) and macrophage infiltration, edema formation, and myonecrosis (ratio: 2.95 ± 0.45) within the left extensor digitorum longus muscle. Cryotherapy for 6 hours significantly restored diminished functional capillary density (393 ± 35), markedly decreased elevated intramuscular pressure, reduced the number of adhering (462 ± 188/cm2) and invading granulocytes (119 ± 28), and attenuated tissue damage (ratio: 1.7 ± 0.17). Conclusion The hypothesis that prolonged cooling reduces posttraumatic microvascular dysfunction, inflammation, and structural impairment was confirmed. Clinical Relevance These results may have therapeutic implications as cryotherapy after closed soft tissue injury is a valuable therapeutic approach to improve nutritive perfusion and attenuate leukocyte-mediated tissue destruction. The risk for evolving compartment syndrome may be reduced, thereby preventing further irreversible aggravation.

Reference genes for the relative quantification of microRNAs in renal cell carcinomas and their metastases.

To obtain accurate results in miRNA expression changes between different sample sets using real-time quantitative polymerase chain reaction (RT-qPCR) analyses, normalization to reference genes that are stably expressed across the sample sets is generally used. A literature search of miRNA expression studies in renal cell carcinoma (RCC) proved that non-miRNAs such as small RNAs or mRNAs have most frequently been used without preceding validation of their suitability. In this study, the most stably expressed miRNAs were ascertained from microarray-based data of miRNA expression in nonmalignant and malignant samples from clear cell RCC and from corresponding distant RCC metastases using the geNorm and NormFinder algorithms. Validation experiments with RT-qPCR were performed for the four best-ranked miRNAs (miR-28, miR-103, miR-106a, miR-151) together with the small RNU6B, RNU44, and RNU48 mostly described in literature. miR-28, miR-103, miR-106a, and RNU48 were proved as the most stably expressed genes. miR-28 is recommended as normalizer if only a single reference gene can be used, while the combinations of miR-28 and miR-103 or of miR-28, miR-103, and miR-106a, respectively, are preferred. RNU6B most frequently used as normalizer in miRNA expression studies should be abandoned in order to avoid misleading results.

Effects of Fondaparinux Compared with Dalteparin, Enoxaparin and Unfractionated Heparin on Human Osteoblasts

The objective of the this study was to examine the effects of fondaparinux, a synthetic anticoagulant substance similar to heparin, on osteoblasts compared with previously used heparins. Its effects have been shown in clinical trials to be highly effective in thromboembolism prophylaxis. Unfractionated heparin (UFH), dalteparin, enoxaparin and fondaparinux were added to osteoblast cultures in the therapeutic range and two decimal powers above and below it in each case. The results showed that the mitochondrial activity and protein synthesis of osteoblasts treated with fondaparinux were significantly higher than in the other groups. Similar effects could be demonstrated for the matrix collagen type II content and calcification. In contrast enoxaparin, dalteparin and UFH lead to a significant decrease of matrix collagen type II content and calcification in concentrations equal or higher than the therapeutic one. No inhibitory in-vitro effects of fondaparinux on human osteoblasts could be demonstrated within the concentration range investigated (0.01 – 100 µg/ml). We conclude that fondaparinux can be used to avoid the heparin-related negative influence on osteoblast-dependent fracture healing and endoprosthetic implant integration.

Massive metallosis after revision of a fractured ceramic head onto a metal head

Abstract. We report a case in which metallosis occurred due to a ceramic head fracture after revision of a total hip prosthesis. In the primary revision, after retrieval of the head fragments, the firmly incorporated stem was left in place, the PE inlay was replaced, and a metal head was inserted. Subsequently, massive metallosis occurred, leading to loosening of the stem and necessitating a two-stage revision. Examinations of the explanted material showed that microparticles of the fractured ceramic head had come to rest in the new PE inlay, where they led to wear on the metal head. We conclude that the use of a metal/PE articular pairing is contraindicated after a ceramic head fracture and recommend the use of a ceramic/ceramic articular pairing in the event of revision. In the case of the stem remaining in situ, this procedure requires the use of a conical stem adapter in order to minimise the fracture risk of the new head.

Higher risk of adjacent segment degeneration after floating fusions: long-term outcome after low lumbar spine fusions.

Study Design We report the long-term outcome after mono-segmental and bisegmental fusions at the lumbar L4-S1 region of the spine. Objective Long-term clinical and radiologic outcome measures were used to determine a lumbar fusions contribution to degenerative changes in adjacent motion segments (ASD). Summary of Background Data The role of low lumbar spinal fusions and their long-term contribution to accelerated degenerative changes in the adjacent motion segments continues to be a subject of controversy. Patients and Methods We followed-up 102 patients with an average age of 54 (22 to 78) years and a follow-up time of 14 (3 to 22) years. Results Overall results in patients were good, the Oswestry-Disability Index (ODI) showed an average of 26% (0% to 70%) at follow-up, the Visual Analog Scale rose from 2.7 (postoperative) and 2.9 (12 wk follow-up) to 3.6 (latest follow-up) points, respectively. Patient satisfaction with their health-related situation at follow-up was 69% (15% to 100%). Patients who underwent fusions of the segment L5/S1 showed a significant (P<0.05) lower risk for ASD than patients with fusions L4/5 (20% vs. 46%). Compared with L4/5 fusions, bisegmental L4-S1 fusions showed a similar trend (P=0.06) with a lower risk for ASD (24%). Objective and subjective clinical results showed no differences between these groups. Patients suffering from ASD showed significant (P<0.05) reduced sacral inclination and lumbar lordosis angles and also significant (P<0.05) higher ODI values compared with non-ASD patients. Conclusions We conclude that floating fusions of single low lumbar segments are more likely to result in ASD and are negatively influenced by sagittal plane abnormalities.

Angular Stable Anterior Plating Following Thoracolumbar Corpectomy Reveals Superior Segmental Stability Compared to Conventional Polyaxial Plate Fixation

Study Design. Biomechanical in vitro testing of primary and secondary stability in 12 human thoracolumbar spinal specimens using a spine simulator. Objective. In a corpectomy model anterior plate systems were investigated for their ability to restore spinal stability particularly focusing on the influence of angular stability, bone mineral density (BMD) and failure mode. Summary of Background Data. The concept of isolated anterior column reconstruction following thoracolumbar fractures using newly developed minimally invasive spine surgical techniques has attracted major clinical interest. In analogy to angular stable plate systems in long bone fixation the application of locking plates to the spine is aimed to limit loss of reduction and to improve stability. Methods. Twelve human spinal specimens (Th11-L3) were tested in a 6-degree-of-freedom spine simulator under pure moments of 7.5 Nm to investigate primary and secondary stiffness of 2 different anterior reconstruction options: (1) Synex II cage and MACS TL polyaxial anterior plating system, (2) Synex II cage and ArcoFix angular stable anterior plating system. An increasing 4-step cyclic loading model was included. Results. The angular stable plate system showed superior stability compared to the nonangular system in axial rotation and lateral bending. Flexion/extension loading demonstrated no difference between the systems in range of motion. A positive correlation between BMD and the number of load cycles until failure for the nonangular stable system (R2 = 0.90) was found. Different failure modes were investigated for the plating systems. The MACS system showed loosening at the connection between screw and plate inducing tilting under flexural load and final failure. The ArcoFix system revealed increased stability under cyclic loading and failed by parallel sintering to the endplate. Conclusion. Anterior angular stable fixation showed higher primary and secondary stability following thoracolumbar corpectomy. In specimens with lower BMD the use of angular stable systems substantially increased stability. Angular stable systems, however, differ in the way of construct failure.

Oncosurgical results of multilevel thoracolumbar en-bloc spondylectomy and reconstruction with a carbon composite vertebral body replacement system.

Study Design. Retrospective clinical study for patients receiving multilevel en-bloc spondylectomy resection for sarcomas and solitary metastases of the thoracolumbar spine. Objective. Assess the clinical and radiologic outcome after multilevel en-bloc spondylectomy and reconstruction. Summary of Background Data. Monolevel en-bloc spondylectomies have proven their oncosurgical effectiveness while reports on multilevel resections for extracompartmental tumor localizations are rare. Methods. Patients treated by multilevel en-bloc spondylectomy and restoration with a carbon composite vertebral body replacement system were investigated. Patient charts, and clinical follow-up investigations were analyzed for histopathological tumor origin, preoperative symptoms, surgical peri- and postoperative data, applied adjuvant therapies, as well as the course of disease. Solitary metastases time until occurrence and prognostic scores were evaluated (Tomita/Tokuhashi Score). CT-scans were performed and analyzed at follow up. Oncological status was evaluated including local recurrence rates, cumulative disease specific, and metastases-free survival. Results. Multilevel (2–5 segments) en-bloc spondylectomy of the thoracolumbar spine was performed in 20 patients (15 sarcomas and 5 solitary spinal metastases 9 male/11 female, mean age at surgery: 54 ± 15 years.). Wide and marginal surgical margins were achieved in 7 and 13 patients, respectively. Mean follow-up period was 25.0 (9–53) months. Thirteen patients received adjuvant therapy. No implant breakage or loosening was observed. Local recurrence occurred in one patient. Thirteen of the 18 surviving patients showed no evidence of the disease, two died of systemic disease. Conclusion. Multilevel en-bloc spondylectomy offers a radical resection option for extracompartmental tumor involvement. It provides oncologically adequate resection margins with low local recurrence. However, the procedures are complex; the patients stress is high and metastatic disease developed in one-third of patients. A judicious patient selection and a realistic feasibility evaluation must precede the decision for surgery. Reconstruction using a carbon composite cage system showed low complication rates and offers advantages for oncosurgical procedures.

Extent of corpectomy determines primary stability following isolated anterior reconstruction in a thoracolumbar fracture model

BACKGROUND Based on the development of minimal-invasive techniques and introduction of new implants enabling secure reconstruction an increasing number of patients are treated by isolated anterior column surgery. Most biomechanical studies dealing with thoracolumbar fracture models use worst-case scenarios of complete corpectomies to simulate vertebral body defects neglecting the influence of remaining cortical bone in partial corpus instability. Using a standardized partial and total corpectomy model we investigated the effect of the extent of corpectomy on stiffness in an anterior reconstruction model. METHODS Twelve human thoracolumbar specimens (Th11-L3) were loaded in a spine simulator with pure moments in the three motion planes. Following intact testing partial corp- and discectomy and later complete corpectomy of L1 were performed. Defects were instrumented by vertebral body replacements and additional anterior plating systems bridging the defect from Th12 to L2. Intersegmental rotations were measured between Th12 and L2. FINDINGS Significantly (P<0.05) increased range of motion was found in reconstructions of total compared to partial corpectomy. Total corpectomy reconstructions showed solely in lateral bending a significant reduction of range of motion compared to the intact state, while in axial rotation and flexion/extension it was significantly increased. Partial corpectomy reconstructions resulted in significantly reduced range of motion for lateral bending and flexion/extension compared to the intact specimen. INTERPRETATION Isolated anterior reconstructions of the thoracolumbar spine revealed sufficient stiffness in the partial vertebral corpus defect. In contrast, total corpectomy did not show an adequate stiffness. Especially in regard to rotational stiffness additional posterior fixation has to be recommended.

Surgical technique of en bloc spondylectomy for solitary metastases of the thoracolumbar spine

DOI 10.1007/s00113-007-1233-7 Online publiziert: 30. Januar 2007