This chapter provides a general overview of current practice in using cement augmentation in tumor treatment, particularly in the spine. Clinical challenges as well as biomechanical mechanisms that compete between long-term and short-term outcomes are discussed. Trends in the development of novel biomaterials for the augmentation in tumor treatment also are presented.

Percutaneous vertebroplasty is a minimally invasive, fluoroscopically guided procedure wherein bone cement, typically polymethylmethacrylate (PMMA), is augmented into structurally weakened vertebrae (30,37). Indications include vertebral hemangioma, osteoporotic compression fractures, and other weakening lesions, such as vertebral myeloma or metastatic vertebral lesions. Unlike in Europe, where vertebroplasty is performed mainly to manage pain due to tumor-related bone diseases (25,26,52,71,94), the focus in North America has been on the relief of pain associated with osteoporotic vertebral fractures that have failed to respond to conservative therapy (40,57,73,75). The clinical success of this procedure is evidenced by the more than 500,000 procedures performed each year in the United States alone (40).

Besides providing additional biomechanical stability, this technique is also performed to alleviate pain by stabilizing metastatically compromised vertebrae that are at risk of pathologic burst fracture (19,67). The antalgic effect is excellent in more than 80% of cases and is very rapid, because a resumption of the support is often possible within 48 hours (39). Optimal cement-distribution patterns to improve biomechanical stability of metastatically involved vertebral bodies, however, remain unknown. The objective of this chapter is to elaborate on the biomechanical effects of cement augmentation in metastatically compromised spinal segments. Specifically, differences between fracture treatment (repair) and preventive treatment (reinforcement) are discussed, as well as variations in the procedure.

Various cancers exhibit the tendency to metastasize to bone, and the thoracolumbar spine is the most frequent site for this complication (3,22,34,36). Osseous metastatic disease in
the spine results in the onset of severe bone pain and structural deficiency, leading to vertebral body fractures and neural deficits (3,34,55,96). Improving the patient’s quality of life depends on achieving spinal stability to reduce pain and prevent neurologic deterioration (56). Conventional surgical decompression and stabilization is a major intervention requiring significant postoperative recovery, but few metastatic cancer patients are good candidates for such a surgery because of their health conditions (18,36,72).

Vertebroplasty for the palliative treatment of malignant spinal tumors has two goals: (a) vertebral stabilization when the lesion threatens the stability of the vertebrae, and (b) analgesic effect. Spinal pain, experienced in more than 70% of affected patients (33), is caused by mechanical micromotion within the osteolytic vertebrae (32). The in situ polymerization of PMMA immobilizes the vertebral body fractured fragments, contributing to the analgesic effect (64). More than 80% of vertebroplasty cases demonstrated significant rapid pain relief and improvement in mobility 24 to 48 hours after the procedure, and in two thirds of cases, prolonged pain relief was observed (7,35,40). Sufficient vertebral stabilization and strengthening require bone-cement filling of both the osteolytic area of the lesion and the surrounding regions of the vertebral body that seem structurally normal (2,32). However, injection of excess bone cement into the lesion must be avoided for fear of complications due to cement leakages (see page 75).

Much of the abstruseness of the ultimate biomechanical goal of vertebroplasty stems from the highly debated issue of what composes fracture risk. Previous biomechanical studies considered the repair of a collapsed vertebra successful when vertebral stiffness or strength was restored to prefracture values (13

Stay updated, free articles. Join our Telegram channel

Join