The authors concluded that there was level III evidence that balloon kyphoplasty was a well-tolerated and relatively safe and effective method for reduced pain and improved functional outcomes in patients with painful neoplastic spinal fractures. These conclusions should be interpreted with some caution due to the possibility of publication bias, lack of comparative data and differences between studies.

To determine the efficacy and safety of balloon kyphoplasty for spinal fractures in cancer patients.

MEDLINE, EMBASE, CINAHL, ISI Proceeding, The Cochrane Library, DARE, NHS EED and HTA Database were searched to September 2008; search terms were reported. References of identified studies and reviews were screened and experts in the area were contacted. No language restrictions were applied. The review was restricted to peer-reviewed studies.

Studies that compared balloon kyphoplasty to any medical or surgical treatment in more than 10 adults with spinal fractures of malignant origin were eligible for inclusion if they provided data on at least one of the following outcomes: pain, functional capacity, quality of life, vertebral height, kyphotic angle, cement leakages, clinical complications and new vertebral fractures.

Mean age in the included studies was 62 years, 51% were male and 57% had multiple myeloma. Most patients had persistent pain secondary to thoracic or lumbar collapses, despite painkillers and medical therapy. Balloon kyphoplasty was performed under general anaesthesia in all but one of the studies. The mean number of spinal levels treated ranged from one to six. Follow-up duration ranged from three months to two years.

Two reviewers independently assessed studies for inclusion.

Risk of bias was assessed according to the following criteria: selection bias (representative sample, consecutive cases); procedure bias (specific cointervention, pre-post assessment); detection bias (blinding, objective results); and attrition bias (follow-up >80%).

The authors did not state how many reviewers performed quality assessment.

Dichotomous data were extracted as relative risks (RR) together with 95% confidence intervals (CI) that compared pre- and post-treatment results. Continuous variables were extracted as the difference between pre- and post-treatment values together with standard deviations (SD). If standard deviations were not reported for continuous data they were estimated from the reported data.

The authors did not state how many reviewers extracted data.

Summary relative risks and standardised mean differences (SMD) or weighted mean differences (WMD) were estimated using random-effects models. Heterogeneity was assessed using the I² statistic.

Seven studies (n=306) were included in the review: three retrospective and four prospective single-centre clinical series. All studies were deemed to have included a representative sample and five enrolled consecutive cases. All except one study reported on specific cointerventions. All studies conducted a pre-post assessment. Three studies were reported to have been blinded; this was not reported in the remaining studies. All studies except one were judged to have reported objective results. Follow-up was greater than 80% in four studies.

Balloon kyphoplasty resulted in significant improvement in pain relief both postoperatively (SMD 3.85, 95% CI 2.99 to 4.71; four studies) and at the end of follow-up (SMD 4.27, 95% CI 2.38 to 6.21; three studies). Functional capacity was also significantly improved postoperatively (WMD -28.8, 95% CI -11.5 to -46.0; four studies) and at six-month and 24-month follow-up. There was substantial heterogeneity for all analyses (I²=79% to 99%), except for those of functional capacity at six-month and 24-month follow-up (assessed by only two studies).

Balloon kyphoplasty improved early vertebral height loss (p=0.001) and spinal deformity (p=0.01), but these effects were not long term. There were no reports of serious procedure-related complications. Clinically asymptomatic cement leakage occurred in 6% of all treated levels and new vertebral fractures in 10% of patients.

There was level III evidence that balloon kyphoplasty was a well-tolerated and relatively safe and effective method for reduced pain and improved functional outcomes in patients with painful neoplastic spinal fractures.

The review addressed a focused question and inclusion criteria were clearly defined. The literature search was adequate for published studies, but the restriction of the review to published studies meant that there was a possibility of publication bias. Appropriate steps were taken to minimise bias and errors in study selection; it was unclear whether such steps were also taken for data extraction and quality assessment. Study quality was formally assessed using appropriate criteria and the results were summarised in a table. Methods of analysis appeared appropriate, but there was substantial heterogeneity between studies and so summary estimates needed to be interpreted with caution.

The authors' conclusions were supported by the results presented, but should be interpreted with caution due to the possibility of publication bias, lack of comparative data and differences between studies.

Practice: The authors did not state any implications for practice

Research: The authors stated that there was a need for long-term high-quality controlled studies to ascertain the clinical role of balloon kyphoplasty for patients with painful neoplastic spinal fractures. Future studies should have consistent reporting of clinically useful outcomes.

Spanish I+D Program (grant P1060816).

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.