Purpose

To compare the efficacy and safety of balloon kyphoplasty (BKP) to non-surgical management (NSM) over 24 months in patients with acute painful fractures by clinical outcomes and vertebral body kyphosis correction and surgical parameters.

Balloon kyphoplasty (BKP) is a minimally invasive treatment for vertebral fractures (VCF) aiming to correct deformity using balloon tamps and bone cement to stabilize the body. Patients with 1 - 3 non-traumatic acute VCF were enrolled within three months of diagnosis and randomly assigned to receive either BKP (N=149) or nonsurgical care (N=151). Follow-up was 2 years.

The mean SF-36 physical component summary (PCS) score improved 5.1 points (95%CI, 2.8-7.4; p<0.0001) more in the kyphoplasty than the nonsurgical group at one month, the primary endpoint of the study.

Kyphoplasty improved the PCS score by an average of 3.0 points (95%CI, 1.6-5.4; p=0.002) during the two-year follow-up. There was a significant interaction between treatment and follow-up time (p=0.003), indicating that the treatment effect over the year is not uniform across follow-up; a result from early improvement that persists in the kyphoplasty group whereas the nonsurgical group shows more incremental improvement over time.

Overall, patients assigned to kyphoplasty also had statistically significant improvements over the two years compared to the control group in global quality of life (EQ-5D), pain relief (VAS), back disability (RMDQ) and days of limited activity (within a two-week period).

There was no statistical significant difference between groups in the number of patients with adverse events or new VCF's over 24 months.

Compared to the control, BKP improved quality of life and reduced back pain and disability and did not increase adverse events including the risk of new vertebral fractures over 2 years.

Background

Vertebral body compression fractures (VCFs) impair quality of life (QOL) and increase patient morbidity and mortality. The international, multicentre, randomised, controlled Fracture Reduction Evaluation (FREE) trial was initiated to compare effectiveness and safety of Balloon kyphoplasty (BKP) to non-surgical management (NSM) for the treatment of acute painful VCFs. We describe the primary endpoint of the ongoing 2-year study.

Purpose: Balloon kyphoplasty (BKP) is a minimally invasive treatment for acute vertebral compression fractures (VCF) that aims both to correct associated vertebral deformity (reduce) and stabilize the fracture by injecting bone cement. We performed the first multicenter randomized trial to assess the effect of BKP.

Method: Patients with 1–3 non-traumatic vertebral compression fractures diagnosed within 3 months were randomly assigned to receive either BKP (N=149) or usual nonsurgical care (NSC) (N=151). Measurements of quality of life, back pain and function, days of disability and bed rest were assessed at baseline, 1, 3, 6 and 12 months.

Results: The primary outcome measure, the difference between groups in change from baseline scores in the physical component summary of the SF-36 questionnaire, improved 3.5 points (95% CI, 1.6 to 5.4; p=0.0004) more in the BKP group when averaged across 12 months of follow-up. Compared with the NSC group, those assigned to BKP also had greater improvement in quality of life and back function throughout 12 months of follow-up as measured by the EuroQol and Roland-Morris scales; a difference of 0.14 points (95% CI, 0.05 to 0.23; p=0.0023) more and 3.2 points (95% CI, 1.7 to 3.8; p< 0.0001) and reported fewer days of limited activity in the previous 2 weeks due to back pain (2.5 fewer days; 95% CI, 1.2 to 3.8; p=0.0001). New radiographically detected vertebral fractures occurred in 41.8% of subjects in the kyphoplasty and 37.8% in the nonsurgical group (4% difference; 95% CI −7.5 to 15.6; p=0.5).

Conclusion: Compared to nonsurgical treatment, balloon kyphoplasty improved multiple measurements of quality of life, back pain and disability that last at least one year after the procedure. No difference is seen between groups in radiographically detected VCF’s (Clinicaltrials.gov number, NCT00211211).

Background: Balloon kyphoplasty is a minimally invasive treatment for acute vertebral fractures that aims to reduce and correct vertebral deformity by inserting expandable balloon tamps and then stabilize the body by filling it with bone cement. The effect of balloon kyphoplasty on quality of life has not been tested in a randomized trial.

Methods: Patients with up to 3 non-traumatic acute vertebral compression fractures were enrolled within 3 months of diagnosis and randomly assigned to receive either balloon kyphoplasty (N=149) or usual nonsurgical care (N=151). Measurements of quality of life, back pain and function, and days of disability and bed rest and spine radiographs were assessed through 12 months of follow-up.

Results: Compared with those assigned to nonsurgical care, participants assigned to balloon kyphoplasty had 5.2 points (95% CI, 2.9 to 7.4; p< 0.0001) greater improvement in the physical component of the SF-36 quality of life questionnaire at one month and 1.5 points (95% CI, − 0.8 to 3.8; p=0.2) at twelve months. Those in the balloon kyphoplasty group also had greater improvement in quality of life by the EuroQol questionnaire at one (0.18 points; 95% CI, 0.08 to 0.28; p=0.0003) and twelve months (0.12 points; 95% CI, 0.01 to 0.22; p=0.025) and improved disability by the Roland-Morris scale at one month (4.0 points; 95% CI, 2.6 to 5.5; p< 0.0001) and twelve months (2.6 points; 95% CI, 1.0 to 4.1; p=0.0012). Balloon kyphoplasty patients had less back pain on a 0 to 10-point numeric rating scale at seven days (2.2 points; 95% CI, 1.6 to 2.8; p< 0.0001) and twelve months (0.9 points; 95% CI, 0.3 to 1.5; p=0.0034) and reported fewer days of limited activity at one month (2.9 days per 2 weeks; 95% CI, 1.3 to 4.6; p=0.0004) and twelve months (1.6; 95% CI, − 0.1 to 3.3; p=0.068). Fewer patients assigned to balloon kyphoplasty took pain medications or used walking aids during follow-up. There was no significant difference in the number of patients with adverse events or serious adverse events in the kyphoplasty and nonsurgical groups. New radiographically detected vertebral fractures occurred in 41.8% of subjects in the balloon kyphoplasty and 37.8% in the nonsurgical group (4% difference; 95% CI − 7.5 to 15.6; p=0.5) and were not statistically different.

Conclusion: Compared to nonsurgical treatment, balloon kyphoplasty safely improved quality of life and reduced back pain, disability and the use of pain medications and walking aids. Significant improvements in multiple measurements of quality of life, pain and disability continue for at least 1 year. Balloon kyphoplasty did not increase adverse events including the risk of vertebral fractures (Clinicaltrials.gov number, NCT00211211).

The biomechanical effects on facet joints after posterior fusion remain unclear and seem to be responsible for accelerated degeneration. The following biomechanical study was performed to investigate the effects on the pressure and mobility of neighbouring unfused segments after double level T12-L2 posterior stabilization.

The experimental study was performed on eighteen fresh, human, cadaveric thoracolumbal spine specimens. The specimens were cleaned and dissected from muscles and fat with care to preserve bone-ligament units intact. In a specially constructed testing machine the data of the segmental pressure and mobility of adjacent segments above and below the fusion were measured before and after double level T12-L2 posterior stabilization with an internal fixator (Universal Spine System) in flexion, extension, lateral bending, and rotation. For measuring the mobility a motion tracker (3Space Fastrak) and for direct evaluation of the pressure a quartz miniature force transducer was used. Also the bone mineral density of the specimens were measured and showed normal values.

In flexion and extension Range of Motion (ROM) of the segment above the double level T12-L2 posterior fusion was significantly increased (p< 0,05). In the adjacent segment below the fusion there was no significant increased mobility after fusion for each moment was applied. The pressure did not show any significant difference, but after posterior fusion in flexion and extension the pressure below the posterior fusion (L2/L3) was decreased and above the fusion (T11/T12) increased.

There is evidence that the adjacent segment above a double-level T12-L2 posterior fusion becomes more mobile and leads possibly to an accelerated degeneration in the facet joints due to increased stress at this point. Also the posterior fusion seems to change the load distribution in the facets of adjacent segments. These results could be responsible for symptoms like low back pain after spinal surgery.

The new distractable titanium implant (Synex) is designated for replacement of the vertebral body following fracture, posttraumatic kyphosis or tumor.

Synex was compared with the “Harms” cage (MOSS, 22x28 mm, stabilising ring) in two test series.

Test A: Measurement of the compressive strength of the vertebral body end-plate in uniaxial loading via both implants; Test B: Analysis of the bisegmental stability after corpectomy, replacement of L1 and stabilisation.

Materials and methods: In testseries A human vertebral specimens (L1) were matched according to bone mineral density (BMD). They were axially loaded (v=5mm/min) to failure via Synex (n=6) or MOSS (n=6) in an electrohydraulic testing device with load-displacement recording.

In test series B the bisegmental motion (T12-L2) of 12 spinal specimens were tested in a 3D loading simulator with moments of 0–7.5 Nm for the six directions. After testing the intact spine, we replaced L1 and stabilised with Fixateur interne (USS) or Ventrofix (VFix). Analysis of the range of motion (ROM), elastic zone (EZ) and neutral zone (NZ) for five conditions: 1) Intact specimen, 2) USS+Synex, 3) USS+MOSS, 4) VFix+Synex, 5) VFix+MOSS (randomized order).

Results: With Synex, significantly higher compression forces were recorded at 1–2 mm deformation. Ultimate compression force (Fmax) was higher (3396 N vs. 2719 N) and the distance until point of failure (Dmax) was significantly less using Synex. A significant correlation (R=0.89) between Fmax and BMD was found.

Significantly higher stability was noted with USS+Synex for extension, lateral bending, and axial rotation. No differences between Synex and MOSS were observed in combination with VFix. The combined instrumentation (USS) was superior to the anterior one (VFix).

The possibility of secondary dislocation, loss of correction, or posttraumatic kyphosis can be decreased using Synex for replacement of the vertebral body, compared with MOSS. A combined anterior-posterior stabilisation provides higher biomechanical stability compared with an anterior construct.