Metastatic bone disease: current concepts of clinicopathophysiology and modern surgical treatment.

Metastases to bone are a common problem confronting both the orthopaedic oncologist and cancer specialists. Early diagnosis requires a knowledge of the pathogenesis of bone metastases. A primary route of metastatic cells is via Batson's vertebral vein plexus. An understanding of the pathophysiology enables the surgeon to plan effective treatment. As many patients continue to survive for prolonged periods following the detection of bone metastases, it is important to plan treatment that is durable and functional. Non-operative treatment is utilised for small lesions (less than 25 percent of the cortical diameter). Radiotherapy (generally 3000 cGy in ten fractions), patient education (to avoid excessive torsional loads), and systemic chemotherapy or hormonal therapy are the mainstays of non-operative treatment. The indications for surgical treatment include: (1) lesions greater than 50 percent the diameter of the cortex, (2) permeative lesions in high stress areas (subtrochanteric region of the hip, mid-femoral diaphysis, mid humeral metaphysis), and (3) lesions in which pain persists following external beam irradiation. Early and effective treatment improves the remaining quality of life in patients with metastatic bone disease. A knowledge of the pathogenesis and pathophysiology aids the clinician in making an early diagnosis.