Overlapping allograft in reconstructive surgery for malignant bone tumours in paediatric patients: a preliminary report.

The use of allografts for the treatment of bone tumours in children is limited by nonunion and the difficulty of finding a suitable graft. Furthermore, appositional growth can't be expected of an allograft. We used an overlapping allograft in 11 children, with a mean age of ten years (4 to 15), with a mean follow-up of 24.1 months (20 to 33). There were five intercalary and six intra-articular resections, and the tumours were in the femur in six cases and the humerus in five. Rates of union, times to union, remodelling patterns and allograft-associated complications were evaluated. No allograft was removed due to a complication. Of the 16 junctional sites, 15 (94%) showed union at a mean of 3.1 months (2 to 5). Remodelling between host and allograft was seen at 14 junctions at a mean of five months (4 to 7). The mean Musculoskeletal Tumor Society score was 26.5 of 30 (88.3%). One case of nonunion and another with screw protrusion required re-operation. Overlapping allografts have the potential to shorten time to union, decrease rates of nonunion and have positive appositional growth effect.

Prognosis of extremity osteosarcoma in patients aged 40-60 years: a cohort/case controlled study at a single institute.

BACKGROUND: The outcome of older osteosarcoma patients with multi-disciplinary management has not been clearly defined. METHODS: We conducted a cohort (n=375) and a case-control (n=78) study on 26 older age patients (40-60 years) with localized osteosarcoma of extremity. In the case-control study, controls were matched for location and initial tumor volume. RESULTS: Compared to 349 younger patients, older age patients showed an osteolytic pattern on plain radiographs (P=0.05), fibroblastic subtype (P<0.01), and poor histologic response (P=0.03). Multivariate analysis revealed that a large absolute tumor volume (P<0.01), a tumor location in the proximal humerus (P=0.02), and a poor histologic response to preoperative chemotherapy (P<0.01) independently predicted poorer metastasis-free survival. However, an older age showed marginal significance (P=0.09). A case-control study showed a higher proportion of the fibroblastic subtype and poor histologic response in the case group. Five-year metastasis-free survival rates for the 26 cases and 52 controls were 40.1+/-10.1% and 61.5+/-6.8%, respectively (P=0.02). CONCLUSIONS: Older age osteosarcoma patients showed an unfavorable histologic response to chemotherapy and lower survival than younger patients. Nevertheless, a further larger-scale study is required to confirm our observations.

Metronidazole pharmacokinetics in patients with acute renal failure.

The pharmacokinetics and metabolism of intravenous metronidazole were studied in six patients with acute renal failure. In two of the patients a single dose (500 mg) of metronidazole was administered, whereas in four patients the steady-state pharmacokinetics were studied after four days therapy of 500 mg twice daily. Plasma concentrations of metronidazole and its hydroxy and acetic acid metabolites were measured by a specific and sensitive HPLC method. The volume of distribution was 0.65 +/- 0.13 l/kg (mean +/- S.D.), elimination half-life was 9.9 +/- 2.5 h and total plasma clearance was 55.5 +/- 17.7 ml/min. Renal clearance was almost non-existent (1.4 +/- 1.4 ml/min), whereas non-renal clearance was 54.0 +/- 18.2 ml/min. Steady-state plasma concentrations of metronidazole were 15.3 +/- 3.8 mg/l, the hydroxy metabolite were 17.4 +/- 2.0 mg/l and the acetic acid metabolite were 1.2 +/- 0.8 mg/l. In the patients studied, a dosing regimen of 500 mg twice daily resulted in therapeutically adequate blood levels of metronidazole.