Sun 2016.

Methods	Design: single‐centre, parallel group, two‐arm randomised controlled trial Setting: China Interventions: high‐viscosity cement percutaneous vertebroplasty or low‐viscosity cement percutaneous kyphoplasty Timing: June 2010 to August 2013 Sample size: sample size calculation not reported Analysis: completers' analysis
Participants	Number of participants Number of participants who were screened is not reported 98 participants randomised (46 in percutaneous vertebroplasty and 52 in percutaneous kyphoplasty) There was no report of missing data or number of participants for the analysis Inclusion criteria Acute back pain No recent history of back trauma or spinal cord compression MRI scanning showing bone oedema in the fractured vertebra Exclusion criteria None reported Baseline characteristics Vertebroplasty Group Mean (SD) age: 65.4 (2.6) years No. female/male: 34/12 Mean (SD) follow‐up (months):22.7 (3.3) No. vertebra bodies: 54 Mean (SD) Injected cement volume (ml): 3.4(0.3) Mean (SD) operative time (min): 45.2 (4.7) Mean (SD) VAS: 8.5 (1.1) Mean (SD) ODI: 70.6 (8.6) Kyphoplasty group (n = 24) Mean (SD) age: 65.2 (3.3) years No. female/male: 38/14 Mean (SD) follow‐up (months):21.7 (2.3) No. vertebra bodies: 60 Mean (SD) Injected cement volume (ml): 4.2 (0.2) Mean (SD) operative time (min): 64 (5) Mean (SD) VAS: 8.2 (0.9) Mean (SD) ODI: 71.7 (8.5)
Interventions	High‐viscosity cement percutaneous vertebroplasty Patients were placed in a prone position and treated with local anaesthesia. The position of fractured vertebra was fixed by using C‐arm fluoroscopy. A scalpel was used to make a 0.5 cm incision on the skin, after which the PVP needles were used to access the back muscle to reach the vertebral body. When the tip of the needle entered the posterior, middle and anterior of vertebral body, the frontal imaging displayed in C‐arm fluoroscopy screen showed the position of the needle to be at the paries lateralis, middle line, and paries medialis of radix arcus vertebrae. When the tip of needle reached the anterior and middle 3/4 of the vertebral body, the position of the needle was adjusted to enable injection of the high‐viscosity cement into the vertebral body. The volume of cement used was about 3 mLto 4 mL per vertebra. The entire surgery proceeding was guided by C‐arm fluoroscopy. Low‐viscosity cement percutaneous kyphoplasty The anaesthesia and puncture techniques were the same as those of high‐viscosity cement PVP. Through the working tunnel made by the needle, cannula, and drill, the balloon was inserted into the centre of the vertebral body and contrast medium was injected using a high pressure pump. Then the balloon was extracted and approximately 4 mL of cement was injected into each vertebral body.
Outcomes	Outcomes were measured at 2 days and 12 months after surgery Study outcomes Pain: Visual Analog Scale (VAS 0 to 10) measuring pain relief Oswestry Disability Index (ODI 0 to 100) assessing functional activity Radiological evaluation with plain digital radiography and CT scan to assess cement leakage, restoration of vertebral height, and the angle of kyphosis (day 2) Outcomes used in this review Pain (VAS) Disability (ODI)
Source of funding	Not reported
Notes	No trial registry record found Adverse events Vertebroplasty: serious adverse events: none reported; other adverse events: cement leakage 9/54 (16.7%) Kyphoplasty: serious adverse events: none reported; other adverse events: cement leakage 11/60 (18.3%)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation process not reported.
Allocation concealment (selection bias)	Unclear risk	Method of allocation concealment not reported.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not clear whether there was blinding of participants and study personnel.
Blinding of outcome assessment (detection bias) Self‐reported outcomes (e.g., pain, disability)	Unclear risk	Since blinding of participants is not confirmed there could be a risk of bias in the measurement of self‐reported outcomes of pain and functional activity.
Blinding of outcome assessment (detection bias) Objective outcomes (e.g., radiographic outcomes)	High risk	Not reported but likely that radiologists would be able to tell the difference between vertebroplasty and kyphoplasty on a radiograph.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No withdrawals reported.
Selective reporting (reporting bias)	Unclear risk	Protocol not found. Trial not registered. The results of all outcomes specified in the methods are reported.
Other bias	Low risk	No other bias apparent.