Aims

Medical comorbidities are a critical factor in the decision-making process for operative management and risk-stratification. The Hierarchical Condition Categories (HCC) risk adjustment model is a powerful measure of illness severity for patients treated by surgeons. The HCC is utilized by Medicare to predict medical expenditure risk and to reimburse physicians accordingly. HCC weighs comorbidities differently to calculate risk. This study determines the prevalence of medical comorbidities and the average HCC score in Medicare patients being evaluated by neurosurgeons and orthopaedic surgeon, as well as a subset of academic spine surgeons within both specialities, in the USA.

Introduction: Platelet-rich plasma (PRP) is a platelet concentration obtained from a few millilitres of blood. It releases several growth factors and can enhance tissue repair(). The aim of the study was to evaluate the efficacy and the safety of PRP in the treatment of experimental induced muscle lesions.

Materials and Methods: 22 adult Wistar rats were used. Blood collected from 2 rats was mixed with citrate-phosphate-dextrose and centrifuged to a gel consistency. Growth factor release was stimulated by the addition of CaCl and thrombin. Identical bilateral incisions were performed on the longissimum dorsi muscle of 20 Wistar rats. Each site was marked by placing a hollow PVC vessel containing PRP on the bottom of the defect. An empty marker was placed on the bottom of the contralateral lesion, as control. Animals were killed 40 or 60 days from surgery. Muscle samples were stained with haematoxylin-eosin. Histomorhometric parameters investigated were: number of regenerating fibres, amount of neoangiogenesis and fibrous tissue, presence of inflammatory cells, metaplasia, calcification and ossification (Leika, Quantimet SD).

Results: Treated muscles exhibited greater neoangiogenesis and a larger number of miocytes in regenerating phase compared with controls. Both groups showed a similar amount of fibrous tissue and some inflammatory cells. Metaplasia, ossification or heterotopic calcification were seen in none of the samples.

Conclusions: To our knowledge this is the first investigation of PRP in muscle healing. Data showed that PRP is effective in improve muscle healing without adverse local effects. Additional experiments are in progress in view of a clinical trial.

Radiological evaluation is crucial for interpretation of experimental osteomyelitis studies. Current scoring systems for radiologic evaluation of experimental osteomyelitis have limitations to demonstrate differences among treatment groups. Response of bone tissue to infection is a dynamic process; each radiological sign of osteomyelitis becomes prominent at different time points of disease. Analysing radiological criteria separately at different stages of the disease may provide better quantification of the response to treatment in experimental osteomyelitis rather than summation of these grades together.

Osteomyelitis was induced with S.aureus in left tibias of 72 adult, wistar albino rats. Rats were assigned into six different treatment groups. Their radiograms were graded according to previously defined scoring systems, and each radiological criterion separately, at the third week of induction, and at the third and sixth week after treatment.

Although periosteal reaction and diaphyseal widening demonstrate significant differences with three weeks of treatment, previously defined scoring systems could not find significant differences. At the sixth week of treatment, only one of the previously defined grading scales was able to differentiate significance among the treatment groups. Individual values of diaphyseal widening, osteolysis, BMC values were pointed out differences among the groups in the presence of osteomyelitis, confirmed by osteomyelitis.

Formulation of radiological grading scales requires evaluation of periosteal elevation, diaphyseal widening, bone deformation, osteolysis, and osteosclerosis, individually. However, evaluation of these scores separately will multiply interpretations of future studies, and will make them more meaningful.

Bisphosphonates are systemically used for the treatment of metabolic bone diseases such as osteoporosis or aseptic loosening after joint replacement surgeries, and there are limited studies on their effects when applied locally. Furthermore, effects of biphosphonates in osteomyelitis treatment are not well-known. A prospective longitudinal randomised controlled study was designed for the rat tibia to test the efficacy of local or systemically administered bisphosphonates for controlling the localised osteolytic reactions and possible effects on local infection control.

Osteomyelitis was induced in the tibia of 72 Wistar albino rats with S. aureus ATCC 25923 strain. All rats in all treatment groups were given curettage and debridement surgery. Rats in Group I were left without any bone grafting. In Group II, dead space was grafted with plain bone graft, while in Group III rats were treated with vancomycin-loaded bone grafts. In group IV, defects were filled with vancomycin-loaded bone grafts, and this was combined with weekly subcutaneous alendronate application at a dose of 240 μg/kg/wk. At Group V defects were grafted with alendronate impregnated bone graft. Finally, rats in Group VI received vancomycin + alendronate impregnated grafts. Dependent variables were groups (n=6) and time (n=2) whereas independent variables were swab cultures, radiology, quantitative computerised tomography, dual energy X-ray absorptiometry and histopathology.

Within three weeks, S.aureus was isolated in all groups. Within six weeks, S.aureus was eradicated in Groups II and IV according to the results of swab cultures. Radiological diaphyseal widening was significantly lower (p=0.037) in Group VI at three weeks. Bone deformation, diaphyseal widening and osteolysis scores were lower in this group at six weeks. Bone mineral content and density measured by quantitative computerised tomography were significantly higher (p=0.001) in Groups IV and VI at six weeks. Bone mineral density measured by dual energy X-ray absorptiometry was significantly higher in Group IV at six weeks. Histology revealed marked osteoblastic activity in Groups IV and VI at six weeks.