✓ Although rare, spinal hydatid disease is a manifestation of hydatid infestation. The authors present the report of a patient who presented with primary spinal hydatid disease. This disease is often misdiagnosed as tuberculous spondylitis, and thus patients may subsequently receive inappropriate treatment. The patient in this case presented, with an increasing weakness in the lower limbs, to a different clinic from an area in India where hydatid infections are endemic. The infection was misdiagnosed as tuberculous spondolytis based on evaluation of plain x-ray films, and the patient underwent antituberculous chemotherapy and a posterior surgical decompressive procedure. The patient presented to the authors' clinic with increasing paraparesis 1.5 years later. Radiographs and a magnetic resonance image of the spine were obtained, which strongly suggested hydatid disease. Examination of serum levels confirmed the diagnosis. The patient underwent a decompressive procedure of the spine in which stabilization was performed. Postoperatively her paraparesis resolved, and good control over the disease was achieved by chemotherapy. The authors conclude that primary spinal hydatid disease of the spine, although a rare manifestation, should be considered in the differential diagnosis in patients with infectious and destructive lesions of the spine in regions in which the disease is endemic. Advanced imaging studies should be performed to diagnose the disease. Early decompressive surgery with stabilization of the spine, in addition to adjuvant chemotherapy, is the treatment of choice for these patients.

Bisphosphonates reduce peri-prosthetic bone loss in the short term after total hip replacement but the mid- and longer term effects are not known. The aims of this randomised trial were to examine the effect of a single dose of 90 mg of pamidronate on the clinical and radiological outcome and peri-prosthetic bone mineral density in 50 patients (56 hips) over a five-year period, following total hip replacement. At five years, 37 patients (42 hips) returned for assessment. The Harris hip scores were similar in the pamidronate and placebo groups throughout the study. Also at five years, four patients, two from each group had osteolytic lesions on plain radiography. These were located around the acetabular component in three patients and in the femoral calcar in one. The femoral and acetabular peri-prosthetic bone mineral density in the pamidronate group and the control group was similar at five years. Pamidronate given as a single post-operative dose does not appear to influence the clinical outcome or prevent the development of osteolytic lesions at five years after total hip replacement.

The aims of this study were to examine the repeatability of measurements of bone mineral density (BMD) around a cemented polyethylene Charnley acetabular component using dual-energy x-ray absorptiometry and to determine the longitudinal pattern of change in BMD during the first 24 months after surgery. The precision of measurements of BMD in 19 subjects ranged from 7.7% to 10.8% between regions, using a four-region-of-interest model. A longitudinal study of 27 patients demonstrated a transient decrease in net pelvic BMD during the first 12 months, which recovered to baseline at 24 months. The BMD in the region medial to the dome of the component reduced by between 7% and 10% during the first three months, but recovered to approximately baseline values by two years. Changes in BMD in the pelvis around cemented acetabular components may be measured using dual-energy x-ray absorptiometry. Bone loss after insertion of a cemented Charnley acetabular component is small, transient and occurs mainly at the medial wall of the acetabulum. After two years, bone mass returns to baseline values, with a pattern suggesting a uniform transmission of load to the acetabulum.

This review of the available literature suggests that, compared with conventional microdiscectomy, microsurgical lumbar sequestrectomy can achieve comparable reherniation rates and reduction in radicular pain when a small breach in the posterior fibrous ring is found intraoperatively.