Biomedical subjects

Arnulf Weckbach

Publications and source records attributed to Arnulf Weckbach.

6 recordsLinked to original sources

PubMed2005

The influence of posterior instrumentation on adjacent and transfixed facet joints in patients with thoracolumbar spinal injuries: a morphological in vivo study using computerized tomography osteoabsorptiometry.

STUDY DESIGN: Subchondral mineralization of adjacent and transfixed facet joints was analyzed in patients with thoracolumbar spinal injuries, both before posterior instrumentation and after removal of the spinal implant. OBJECTIVE: To examine the influence of posterior instrumentation on content and distribution of subchondral mineralization as a correlate of the long-term load acting on the adjacent and transfixed zygapophysial joints. SUMMARY OF BACKGROUND DATA: Posterior stabilization plays an important role in the treatment of spinal injuries and is a standard technique for the treatment of thoracolumbar spinal fractures. Studies have shown that stress and motion in the adjacent segments are altered in the presence of instrumentation. METHODS: Twenty-three patients with thoracolumbar spinal injuries had computerized tomography (CT) during the course of routine posttraumatic diagnostics and subsequently received bisegmental posterior fixation with an internal fixator. Second CT were obtained after removal of the fixation device, which was performed on an average of 9.4 months after the trauma. Patients were divided into 2 groups with follow-up CT taken within either less than 3 months (group A: average 7.3 days, 15 patients) or 6 and more months (group B: average 17 months, 8 patients) after the internal fixator had been removed. Quantitative and qualitative CT osteoabsorptiometry were used to assess changes in subchondral mineralization, reflecting the altered load acting on the adjacent and bridged zygapophysial joints. RESULTS: There was a significant difference between preoperative and postoperative calcium values (P < 0.001) for the whole patient group. Mineralization decrease was significantly more often found than increase (P < 0.001). A separate analysis of the 2 groups of patients revealed significant differences between group A and B (P < 0.001). In group A, a mineralization decrease was found in 61.3% and an increase in 11.0% of the facet joints, while in group B, a mineralization decrease was shown in 21.9% and an increase in 41.0%. No significant differences between adjacent and transfixed facets were found except in group B, in which the suprajacent joints showed a significantly higher mineralization increase than the transfixed joints (P = 0.030). CONCLUSIONS: Decrease in subchondral mineralization indicates reduced load acting on the examined zygapophysial joints. This finding in patients with early follow-up CT seems to be caused by reduced activity in most of the patients until removal of the spinal implant. In patients with longer intervals between removal of the fixator and second CT, higher loads acting on the adjacent and bridged joints are shown morphologically. Whether or not these changes lead to spondylarthritis has to be studied in a long-term follow-up.

Adolescent↗

PubMed2005

Bilateral patellar tendon rupture without predisposing systemic disease or steroid use: a case report and review of the literature.

Simultaneous bilateral patella tendon ruptures are very rare injuries of the knee extensor complex often associated with systemic disorders such as lupus erythematosus or rheumatoid arthritis. We describe the case of a 34-year-old man without concomitant systemic disease or steroid use and provide the most comprehensive review of the German and English literature. Furthermore, we discuss the predisposing factors and causal mechanisms as well as current diagnostic procedures and treatment options. In the literature review, only a few patients without systemic disorder or steroid medication present with potential predisposing factors that may be responsible for degenerative changes of the patella tendon, weakening its stability. In addition, in most of these cases, it remains difficult to explain the bilateral and simultaneous nature of this injury.

Adrenal Cortex Hormones↗

PubMed2004

Skill dependence of radiation exposure for the orthopaedic surgeon during interlocking nailing of long-bone shaft fractures: a clinical study.

INTRODUCTION: The objective of this clinical trial was to determine whether there is a skill dependence for the total amount of radiation exposure to orthopaedic surgeons caused by fluoroscopy during intramedullary fracture fixation. MATERIALS AND METHODS: Surgical teams were assigned to either the 'Senior group' or the 'Junior group' according to their professional qualification and clinical appointment. Twenty-two long-bone shaft fractures were stabilized with intramedullary nails. The radiation exposure was measured at different body locations including fingers, trunk and head by means of thermoluminescent LiF:Mg,Cu,P detectors. The total time of fluoroscopy was registered for each operation. RESULTS: Mean time of fluoroscopy per operation was 4.43 min for the 'Senior group' and 6.95 min for the 'Junior group'. The surgeons' hands were exposed to markedly higher doses (range 0-2.88 mSv 'Senior group'; 0-11.94 mSv 'Junior group') than their trunk and head (range 0-0.27 mSv 'Senior group'; 0-0.38 mSv 'Junior group'). After analysis of variance, differences between both groups proved to be statistically significant for all fingers measured (p</=0.02) and for the total time of fluoroscopy (p=0.019). CONCLUSIONS: Generally, the hands are at higher risk than are the trunk and the head, and this finding is independent of surgical skills. However, an additional hazard is created for the less experienced surgeon by a highly varying and poorly predictable exposure of the hands and time needed for fluoroscopy. Thus, the use of radiation is more consistent and standardized with a skilled surgeon.

Clinical Competence↗

PubMed2004

Talar dislocations.

From 1987-2003, 36 patients were treated for talar dislocation, 27 patients for subtalar, six for total talar, and three patients for peritalar dislocation. Luxatio pedis sub talo: We found 19 medial closed, seven lateral closed and one third degree open subtalar dislocations. Our therapeutic concept provides for immediate reduction, which is possible by closed procedure for the majority of medial dislocations. If there is a tendency to redislocation, we perform talonavicular K-wire transfixation. In the case of irreducibility, open reduction via lateral approach is the rule. The lateral dislocation type is often accompanied by additional fractures of the hindfoot and tarsus, frequently requiring primary open procedures via medial approach. 32 patients were followed-up in whom we found 17 excellent results, ten good, three mediocre and two poor results. With two thirds of the patients, low grade arthrosis at least was observed and two thirds showed a reduced amplitude of motion in one or more talar joints. A definite correlation between arthrosis and reduced function was not established. We did not find talar necroses, persisting instabilities, or redislocations. Luxatio tali totalis: We found three lateral and three medial complete dislocations. The therapeutic concept consists of immediate reduction-only possible by open procedure. A tendency to redislocation requires K-wire transfixation. All patients were followed-up. We found two good and four poor results, with two total and three partial necroses. As a secondary treatment, two lower ankle joint(LAJ) and two upper ankle joint (UAJ) arthrodeses were performed. There were no talectomies, amputations, or infections. Luxatio pedis cum talo: We found three anterolateral UAJ dislocations. Our therapeutic concept provides for immediate reduction. The whole capsular ligament apparatus was reconstructed by primary or secondary treatment, depending on the degree of soft tissue damage. Follow-up showed two excellent results

Adolescent↗

PubMed2002

Successful transpedicular lumbar interbody fusion by means of a composite of osteogenic protein-1 (rhBMP-7) and hydroxyapatite carrier: a comparison with autograft and hydroxyapatite in the sheep spine.

STUDY DESIGN: Transpedicular lumbar interbody fusion (TLIF) was performed in a sheep model comparing three treatment groups: a composite of osteogenic protein (OP)-1 and hydroxyapatite carrier (HA), HA without OP-1, and autograft. OBJECTIVE: To evaluate the efficacy of the composite of OP-1 and HA (HA-OP-1) in achieving reliable TLIF. SUMMARY OF BACKGROUND DATA: Anterior fusion techniques directly address disc-related problems and achieve primary axial stability. However, they are characterized by high morbidity. Alternatively, the theoretically advantageous posterior TLIF technique using autograft fails clinically because it lacks compressive stability. METHODS: In 36 sheep, lumbar vertebrae L4 to L6 were instrumented posteriorly. Endoscopically assisted TLIF of L4 to L5 was performed. In 12 sheep, the defect was filled with injectable HA-OP-1. Another 12 sheep were treated with HA and another 12 with autograft. Animals were killed at 8 weeks and evaluated by radiologic, histologic, and histomorphometric analysis and by fluorochrome labeling. RESULTS: Only 10 autograft sheep were available for evaluation. Radiologically and histologically, TLIF with HA-OP-1 led to a fusion rate of 10 in 12 compared with autograft (one in 10 fused) and HA (two in 12 fused) ( = 0.0016). Semiquantitative radiologic and histologic scoring also revealed significant differences with superiority of HA-OP-1 ( = 0.0011). Compared with HA, HA-OP-1 presented significantly more ossification at the bone-cement interface ( = 0.0003) and less cement resorption ( = 0.0209). In four of 12 HA sheep, excessive resorption was responsible for local aseptic inflammation. CONCLUSIONS: Biointegration of the osteoconductive HA does not occur, because shear forces cause early HA fracture, subsequent fragmentation, and gross resorption (initiating severe inflammation in four of 12 sheep). In contrast, osteoinductive effects of HA-OP-1 enable bio-integration, resulting in full osseous composite sheathing and solid fusion. By use of this composite, TLIF is successfully applied in sheep. Harvesting autograft and the anterior approach are avoided.

Animals↗

PubMed2002

Recombinant human bone morphogenetic protein-2 for treatment of open tibial fractures: a prospective, controlled, randomized study of four hundred and fifty patients.

BACKGROUND: The treatment of open fractures of the tibial shaft is often complicated by delayed union and nonunion. The objective of this study was to evaluate the safety and efficacy of the use of recombinant human bone morphogenetic protein-2 (rhBMP-2; dibotermin alfa) to accelerate healing of open tibial shaft fractures and to reduce the need for secondary intervention. METHODS: In a prospective, randomized, controlled, single-blind study, 450 patients with an open tibial fracture were randomized to receive either the standard of care (intramedullary nail fixation and routine soft-tissue management [the control group]), the standard of care and an implant containing 0.75 mg/mL of rhBMP-2 (total dose of 6 mg), or the standard of care and an implant containing 1.50 mg/mL of rhBMP-2 (total dose of 12 mg). The rhBMP-2 implant (rhBMP-2 applied to an absorbable collagen sponge) was placed over the fracture at the time of definitive wound closure. Randomization was stratified by the severity of the open wound. The primary outcome measure was the proportion of patients requiring secondary intervention because of delayed union or nonunion within twelve months postoperatively. RESULTS: Four hundred and twenty-one (94%) of the patients were available for the twelve-month follow-up. The 1.50-mg/mL rhBMP-2 group had a 44% reduction in the risk of failure (i.e., secondary intervention because of delayed union; relative risk = 0.56; 95% confidence interval = 0.40 to 0.78; pairwise p = 0.0005), significantly fewer invasive interventions (e.g., bone-grafting and nail exchange; p = 0.0264), and significantly faster fracture-healing (p = 0.0022) than did the control patients. Significantly more patients treated with 1.50 mg/mL of rhBMP-2 had healing of the fracture at the postoperative visits from ten weeks through twelve months (p = 0.0008). Compared with the control patients, those treated with 1.50 mg/mL of rhBMP-2 also had significantly fewer hardware failures (p = 0.0174), fewer infections (in association with Gustilo-Anderson type-III injuries; p = 0.0219), and faster wound-healing (83% compared with 65% had wound-healing at six weeks; p =0.0010). CONCLUSIONS: The rhBMP-2 implant was safe and, when 1.50 mg/mL was used, significantly superior to the standard of care in reducing the frequency of secondary interventions and the overall invasiveness of the procedures, accelerating fracture and wound-healing, and reducing the infection rate in patients with an open fracture of the tibia.

Adolescent↗