Vogl 2013

Methods	Design: multicentre, two‐arm, randomised controlled trial Setting: Germany (3 centres) USA (1 centre) Timing: March 2008 to Sept 2009 Interventions: percutaneous vertebroplasty versus kyphoplasty Sample size:a priori sample size calculation not reported Analysis: completers' analysis
Participants	Number of participants Number of participants who were screened is not reported 78 participants randomised 1:2 (28 (39 levels) in the percutaneous vertebroplasty and 49 (65 levels) in the cement directed kyphoplasty system groups respectively) Data were available for 23 (82%) in vertebroplasty group and 37 (76%) in kyphoplasty group at the 3‐month follow‐up Data were available for 19 (68%) in vertebroplasty group and 28 (57%) in the kyphoplasty group at the final 12‐month follow‐up Inclusion criteria Up to three painful vertebral compression fractures between T4 and L5 unresponsive to at least 6 weeks of conservative treatment or were admitted to hospital for acute back pain Confirmed diagnosis of osteoporosis or osteopenia Exclusion criteria Burst fractures Planar collapse Vertebral bodies having inadequate space between endplates for cavity creation Infection Current cancer treatment at the affected level Multiple myeloma Prior cement at the affected level Baseline characteristics Vertebroplasty Mean (SD) age: 74 (11.5) years; 19 female, 9 male Mean (SD) pain at baseline: 8.49 (1.18) Usual care Mean (range) age: 80 (71 to 93) years; 21 female, 3 male Mean (SD) pain at baseline: 8.31 (1.12)
Interventions	Percutaneous vertebroplasty The procedure was performed using a bipedicular cement injection in accordance with each participating physician's standard technique. The same cement was used for both procedures (Spineplex, Stryker Instruments, Kalamazoo, MI). Cement directed kyphoplasty system The kyphoplasty system was provided by Soteira Inc, Natick, MA. The surgical procedure began with access gained through a unilateral intrapedicular or extrapedicular approach. The curved design of the cavity creation instrument allowed the physician to drill a curved path from one pedicle, crossing the sagittal midline and stopping with the contralateral anterior quadrant of the vertebral body. The drill converted to a cavity cutting reamer in situ, which created a 10‐mm diameter cylindrical cavity. The cement directing implant consisted of a non load‐bearing, hollow, passively self‐expanding cylindrical device manufactured from a textile composite of nitinol wire, polyethylene teraphthalate fibre, and polycarbonate urethane. The implant was 10 mm in diameter and 15 mm, 20 mm or 25 mm long. The size of the implant was chosen to match the length of the cavity. The implant was designed to contain initially‐injected cement then regulate and direct cement flow into surrounding cancellous bone. Because the cavity was created by cutting, in contrast to bone compaction as in a balloon kyphoplasty, cement was able to penetrate into the bone beyond the boundaries of the cavity. Cement injection into the implant and directed through openings in its wall created a cement mantle in the anterior vertebral body, which extended towards the endplates and stabilised the fracture by filling cracks and voids, interdigitating with viable cancellous bone. Device placement in a centrally‐located cavity provided bilateral cement flow with the vertebral body, crossing both sides of the sagittal midline using a unipedicular approach. The nitinol‐based implant is expanded prior to cement injection to create a barrier to limit posterior cement flow into the basivertebral vein and spinal canal, while still allowing cement to permeate the vertebral body.
Outcomes	Patient follow‐up occurred at 3 and 12 months. Plain radiographs and CT scans were taken within 24 hours of the procedure and at 3 months, and plain radiographs were also taken at 12 months. Outcomes Cement leakage rates based primarily on postoperative CT scans, supplemented by A/P and lateral radiographs Cement leakage location using a newly developed leak location classification method (1. anterior, 2. lateral, 3. neuroforamen, 4 spinal canal or 5. superior or inferior endplate leaks). Changes in vertebral height determined by comparing CT scans obtained postoperatively and at 3 months Long‐term stability of the cement mantle Presence of new fractures at treated or adjacent level Pain intensity on a visual analogue scale (VAS) (not reported in the published paper but referred to in a congress abstract of the same trial reported in German, no data available) Disability assessed by the Oswestry Disability Index (ODI) was measured but these data are not presented in this paper (not reported in the published paper but referred to in a congress abstract of the same trial reported in German) Outcomes included in this review Presence of new fractures at treated or adjacent level
Source of funding	Funding provided by Soteira Inc. (Natick, MA)
Notes	Trial reported to be registered with ClinicalTrials.gov with ID: NCT00576546 but this could not be verified. No efficacy outcomes were reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Participants were randomised into vertebroplasty or cement‐directed kyphoplasty in a ratio of 1:2 but the method of generating the random sequence was not reported.
Allocation concealment (selection bias)	Unclear risk	Whether or not treatment allocation was concealed is not reported.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Participants were blinded but investigators were not blinded.
Blinding of outcome assessment (detection bias) Self‐reported outcomes (e.g., pain, disability)	Low risk	Participants were blinded to treatment allocation.
Blinding of outcome assessment (detection bias) Objective outcomes (e.g., radiographic outcomes)	High risk	Cement leakage, changes in vertebral body height and the incidence of new fractures measured by investigators using radiographs were assessed by the investigators who were aware of treatment assignment.
Incomplete outcome data (attrition bias) All outcomes	High risk	A completers' analysis was performed. Data were available for 23 (82%) and 37 (76%) in vertebroplasty and kyphoplasty groups, respectively at the 3‐month follow‐up and 19 (68%) and 28 (57%) at the final 12‐month follow‐up. It is unclear it this is significantly different and the reasons for missing data are not reported.
Selective reporting (reporting bias)	High risk	A Congress abstract of the same trial is reported in German (https://www.thieme‐connect.com/products/ejournals/abstract/10.1055/s‐0031‐1279397), and indicates that pain intensity on a visual analogue scale (VAS) and disability assessed by the Oswestry Disability Index (ODI) were measured but these data are not presented in this paper.
Other bias	Unclear risk	The role of Soteira Inc. (Natick, MA) in the trial, other than supply of the Cement Directed Kyphoplasty System, is not explicitly reported.