No abstract

Affordability of water services is a pressing water policy issue for both the developed and, in particular, for the developing world. Despite its well-known theoretical shortcomings, affordability analysis of water supply has, up to now, been widely based on the ratio of a household's water expenditure to its income, the Conventional Affordability Ratio (CAR). However, in the housing sector, alternative concepts for measuring affordability have been developed, among them being the ‘Potential Affordability Approach’ (PAA) and the ‘Residual Income Approach’ (RIA). Against this background, this paper compares these three prominent affordability measures (CAR, PAA, RIA) on the basis of an empirical case study of a peri-urban, low-income area in the second largest Mongolian city of Darkhan, using household data from a survey conducted in 2009. Thus we gain insight into both the water-related affordability situation of people in Mongolia, checking the World Bank's finding of an absence of water affordability problems in peri-urban areas in the Mongolian capital Ulaanbaatar, as well as into the comparative functionality of different affordability measures. It is shown that affordability problems do occur but have to be distinguished depending on the economic causation. We argue that none of the regarded measures give a satisfyingly contoured notion of affordability properly distinguished from the adjacent problems of poverty and access.

Primary malignant tumours should be resected with wide margins. This may be difficult to apply to lesions of the spine. We undertook total vertebrectomy on seven patients, four males and three females with a mean age at operation of 26.5 years (6.3 to 45.8). The mean follow-up was 52.3 months. Histological examination revealed a Ewing's sarcoma in two patients and osteosarcoma, leiomyosarcoma, spindle-cell sarcoma, chondrosarcoma and malignant schwannoma in one each. In five patients, histological examination showed that a wide resection had been achieved. At follow-up there was no infection and a permanent neurological deficit was only seen in those patients in whom the surgical procedure had required resection of nerve roots. Despite the high demands placed on the surgeon and anaesthetist and the length of postoperative care we consider total vertebrectomy to be an appropriate procedure for the operative treatment of primary malignant lesions of the spine. Metastases in the spine are common and account for 40% to 60% of secondary osseous lesions. Surgical treatment involves intralesional or marginal resection and stabilisation in order to release the neural structures, provide relief from pain and allow walking.1 In contrast to metastases, primary malignant tumours affect the spine in only 1% to 2% of patients. 2 Of the 4767 lesions listed in the Vienna Bone Tumour Registry, 1715 were primary malignant tumours of which 44 were in the spine, 2.5% of all primary malignancies of bone.Adequate surgical treatment of primary malignant bone tumours of the limbs involves wide or radical resection in combination with neoadjuvant chemotherapy and, if responsive, radiotherapy. The aim of preoperative chemotherapy is to reduce the viable tumour mass and to prevent further dissemination. The combination of systemic and surgical treatment offers the patient a good chance of survival with a satisfactory quality of life.

Age itself cannot be considered a contraindication.

In case of revision or minimal invasive spinal surgery, the amount of autograft possibly harvested from the lamina and the spinous processes is limited. Ekanayake and Shad (Acta Neurochir 152:651-653, 2010) suggest the application of bone shavings harvested via high speed burr additionally or instead, but so far no data regarding their osteogenic potential exist. Aim of the study was to compare the osteogenic potential of bone chips and high speed burr shavings, and to evaluate the applicability of bone shavings as an autograft for spinal fusion. Bone chips and shavings from 14 patients undergoing spinal decompression surgery were analyzed using in vitro tissue culture methods. Osteoblast emigration and proliferation, viability and mineralization were investigated and histological evaluation was performed. Bone chips from all patients showed successful osteoblast emigration after average 5.5 days. In contrast, only 57% of the corresponding bone shavings successfully demonstrated osteoblast emigration within an average time span of 14.8 days. Average osteoblast mobilisation was 1.25 9 10 6 cells per gram from bone chips and 1.73 9 10 5 cells per gram from the corresponding bone shavings. No difference was observed regarding cell viability, but population doubling times of bone chip cultures were significantly lower (50.5 vs. 121 h) and mineralization was observed in osteoblasts derived from bone chips only. Although some authors suggest the general applicability of laminectomy bone shavings as autografts for spinal fusion, autologous bone grafts obtained from laminectomy bone chips are superior in terms of cell delivery, cell proliferation and mineralization.