2 The procedure
2.1.1 Radiotherapy is commonly used to treat patients with painful bony malignancy, although pain may not be relieved for up to 2 weeks after the procedure. Conservative therapy involves analgesia (often with narcotic drugs) and bed rest. However, in some patients, pain remains refractory to both pharmacological and radiation treatment.
2.1.2 Percutaneous cementoplasty is indicated for patients with painful bone metastases resulting from tumours elsewhere in the body or, less frequently, with primary bone tumours. The aim of the procedure is to reduce pain and stabilise bones. Cementoplasty is the generic term for this procedure. Its use in vertebrae is commonly termed vertebroplasty (see section 3.1), and when treating the sacrum it may be described as sacroplasty.
2.2.1 Percutaneous cementoplasty involves the injection of acrylic bone cement into malignant bone cavities in order to relieve pain or stabilise the bone, or both.
2.2.2 Percutaneous cementoplasty may be performed under general anaesthesia or, more commonly, using conscious sedation and local anaesthesia. A small skin incision is made and a 10–12-gauge trocar or needle is passed into the bone under fluoroscopic guidance.
2.2.3 Cement containing a radiopaque agent is used for this procedure. Visualisation of the cement during injection via multi-plane fluoroscopy is essential in order to limit extra-osseous leakage of cement. If leakage outside the bone occurs, the injection is halted while the cement hardens and plugs the leak, or for the needle to be repositioned.
2.2.4 Once the procedure is complete, the patient should remain recumbent and should not bear weight while the cement hardens.
2.3.1 In 14 patients in a case series, pain scores (measured using a self-reported visual analogue scale) improved from a mean 8.8 points at baseline to 1.9 points after cementoplasty (p < 0.0016). In another two studies, good pain relief was achieved in 82% (9/11) and 93% (13/14) of patients. In another case series, 22% (4/18) of patients had 'total improvement' in pain (no pain without analgesics), while 39% (7/18) had clear improvement at 72-hour follow-up.
2.3.2 Two studies reported mobility outcomes. One reported overall improvements in mobility in 93% (13/14) of patients at 1-week follow-up; the other study of 18 patients reported an improvement in mean walking score (on a 0–4 scale) from 1.1 at baseline to 2.1 at 1-month follow-up.
2.3.3 The evaluation of technical success varied across the studies. In one case series, cementoplasty was considered technically successful in all 14 patients; in another, good filling was demonstrated on postoperative computed tomography scans in 39% (7/18) of patients. For more details, refer to the 'Sources of evidence' section.
2.3.4 The Specialist Advisers noted that the procedure was a variation on the existing technique of vertebroplasty.
2.4.1 Among four case series, leakage of injected cement was reported in 6% (1/18), 14% (2/14), 27% (3/11) and 50% (9/18) of patients, although the definition of leakage varied between studies. Symptoms relating to cement leakage were reported in between 6% (1/18) and 11% (2/18) of patients. One case report described an incident in which sudden intra-articular cement leakage led to a covering of part of the femoral head. Subsequent chondrolysis in 75% of the joint space required total hip replacement at 12 weeks.
2.4.2 Transient worsening of pain was recorded in 73% (8/11) of patients in one study. Other reported complications included fever (below 39°C) following the intervention in 45% (5/11) of patients and an increase in serum creatinine levels in 9% (1/11) of patients. For more details, refer to the 'Sources of evidence' section.
2.4.3 The Specialist Advisers noted that theoretical adverse events may include death from cement venous embolus, and nerve or vascular injury as a result of local cement leakage. Pathological fractures may occur. Infection, bleeding and thermal damage caused by the cement are additional concerns. One Specialist Adviser noted that heat produced as the cement hardens may cause damage to neural structures.