Risk Factors for Residual Back Pain After Balloon Kyphoplasty for Osteoporotic Vertebral Fracture

Background

Balloon kyphoplasty (BKP) is a method for the management of osteoporotic vertebral body fracture (OVF). However, improvement in back pain (BP) is poor in some patients, also previous reports have not elucidated the exact incidence and risk factors for residual BP after BKP. We clarified the characteristics of residual BP after BKP in patients with OVF.

Hypothesis

In this study, we hypothesize that some risk factors may exist for residual BP 2 years after the treatment of OVF with BKP.

Patients and Methods

A multicenter cohort study was performed where patients who received BKP within 2 months of OVF injury were followed-up for 2 years. BP at 6 months after surgery and final observation was evaluated by Visual Analog Scale (VAS) score. Patients with a score of 40 mm or more were allocated to the residual BP group, and comparisons between the residual back pain group and the improved group were made for bone density, kyphosis, mobility of the fractured vertebral body, total spinal column alignment, and fracture type (fracture of the posterior element, pedicle fracture, presence or absence of posterior wall damage, etc.). Also, Short Form 36 (SF-36) for physical component summary (PCS) and mental component summary (MCS) at the final follow-up was evaluated in each radiological finding.

Results

Of 116 cases, 79 (68%) were followed-up for 2 years. Two years after the BKP, 26 patients (33%) experienced residual BP. Neither age nor sex differed between the groups. In addition, there was no difference in bone mineral density, BKP intervention period (period from onset to BKP), and osteoporosis drug use. However, the preoperative height ratio of the vertebral body was significantly worse in the residual BP group (39.8% vs. 52.1%; p = 0.007). Two years after the operation, the vertebral body wedge angle was significantly greater in the residual BP group (15.7° vs. 11.9°; p = 0.042). In the multiple logistic regression model with a preoperative vertebral body height ratio of 50% or less [calculated by receiver operating characteristic (ROC) curve], the adjusted odds ratio for residual BP was 6.58 (95% confidence interval 1.64-26.30; p = 0.007); similarly, patients with vertebral body height ratio less than 50% had a lower score of SF-36 PCS 24.6 vs. 32.2 p = 0.08.

Conclusion

The incidence of residual BP 2 years after BKP was 33% in the current study. The risk factor for residual BP after BKP was a preoperative vertebral body height ratio of 50% or less, which should be attentively assessed for the selection of a proper treatment scheme and to provide adequate stabilization.

Level of Evidence

III.

Do we have to pursue complete reduction after PVA in osteoporotic vertebral compression fractures: a finite element analysis

BACKGROUND

Consensus regarding the optimal amount of bone cement and vertebral height in the treatment of osteoporotic vertebral compression fractures (OVCFs) is lacking. Our purpose was to explore the optimal amount of bone cement and vertebral height in OVCF after percutaneous vertebral augmentation (PVA).

METHODS

A three-dimensional finite element model of the L1-L3 segments was constructed from CT scans of aging osteoporosis patients. Four different postoperative vertebral height models were simulated according to Genant semiquantitative grades 0, 1, 2, and 3. The volume of bone cement filling ranged from 3 ml to 6 ml. These models evaluated the von Mises stress of injured vertebral bodies, adjacent vertebral bodies and intervertebral discs under flexion, extension, left flexion, and right flexion after PVA.

RESULTS

When the bone cement content was held constant, as the height of the vertebral body decreased, the stress of the L2 vertebral body decreased during left flexion and right flexion, but the stress of the L2 vertebral body increased and decreased during flexion and extension. As the height of the vertebral body decreased, the stress of the L1-L2 intervertebral disc increased. There was no significant change in the stress of other adjacent vertebrae or intervertebral discs. When the Genant grade was 0, 1, or 2 (3 ml and 4 ml), the stress of the overall vertebral body was closest to normal.

CONCLUSIONS

When the height of the vertebral body is restored to the same height, a bone cement filling volume of 3 ml to 6 ml is suitable and will not produce a significant change in the stress of the vertebral body or adjacent vertebral body. As vertebral body height was lost, it may promote the degeneration of the intervertebral disc above the injury vertebrae after PVA. It is appropriate for the height of the vertebral body to return to Genant grade 0 or Genant grade 1 after surgery. When the height of the vertebral body has Genant grade 2 status, it was best to use 3 ml to 4 ml of bone cement filling. Therefore, when treating OVCFs, clinicians do not need to pursue complete reduction of the vertebral body. It is also important to verify the biomechanics results in clinical studies.

Early loss of angular kyphosis correction in patients with thoracolumbar vertebral burst (A3-A4) fractures who underwent percutaneous pedicle screws fixation

Purpose

Percutaneous trans-pedicle screws represent a surgical option frequently performed in patients affected by thoracolumbar vertebral burst fractures (A3-A4). The aim of the study was to evaluate the early loss of kyphosis correction and its clinical correlations in a cohort of patients affected by burst spinal fracture treated with percutaneous trans-pedicle screws fixation.

Methods

The present investigation consists in a retrospective one center analysis. The primary outcome was the evaluation of the early loss of correction. Secondary outcomes were the bi-segmental kyphosis change, the clinical outcome and the correlation between clinical outcome and the loss of correction.

Results

Among 435 patients 97 were included in the study. A mean 3.3° of early loss of correction was observed between postoperative and 1 month follow-up evaluations. The mean anterior vertebral body height change was 3.8 mm. No statistical differences were found in clinical and functional outcomes between patients with >2° or <2° of kyphosis loss of correction.

Conclusion

No statistical differences were found between 1 e 6 months postoperative kyphosis loss of correction. The amount of loss of correction seems not to influence clinical outcomes after percutaneous trans-pedicle screw fixation in patients with vertebral burst fractures.

Effect of RTS versus percutaneous conventional pedicle screw fixation on type A thoracolumbar fractures: a retrospective cohort study

PURPOSE

This study aims at evaluating the effects of RTS (rotation softened trauma fixation system) compared with PCPSF (percutaneous conventional pedicle screw fixation) on type A thoracolumbar fractures.

METHODS

In this retrospective cohort study, 116 patients with type A thoracolumbar fractures from March 2014 to June 2018 were enrolled. PCPSF was performed in 60 patients, meanwhile the other 56 patients accepted RTS. VAS scores, Cobb angle, anterior vertebral height (AVH) and perioperative data were compared between the two groups.

RESULTS

Both groups were consistent with baseline on demographic and clinical characteristics. No significant difference was observed in VAS score between-group before and after operation. One year after surgery, the VAS score of RTS group was lower than that of PCPSF group (0.7 ± 0.3 vs. 1.5 ± 0.4). The postoperative AVH (%) in PCPSF was 82.3% (95%CI, 81.7-84.6), and 91.78% (95% CI, 91.1-92.4) in RTS. The postoperative improvement rate of AVH (%) in RTS was higher than that in PCPSF (30.6 ± 5.0 [95% CI, 29.2-32.0] vs. 22.0 ± 7.3 [95% CI, 20.2-24.2]). The postoperative Cobb angle (°) in PCPSF was 2.6 ± 3.4 (95%CI,11.7-13.5), and 7.5 ± 2.0 (95%CI,7.0-8.0) in RTS. The postoperative correction of Cobb angle (°) in RTS was higher than that in PCPSF (16.1 ± 3.8 95%CI,15.1-17.1] vs. 11.6 ± 5.2 95%CI,10.3-13.1]).

CONCLUSIONS

Compared with PCPSF, RTS has advantages in restoring the anterior vertebral height and reducing local kyphosis.

Percutaneous kyphoplasty: Risk Factors for Recollapse of Cemented Vertebrae

INTRODUCTION

Percutaneous kyphoplasty can offer pain relief and restoration of vertebral height immediately after the procedure; however, little is known about how many vertebrae recollapse during follow-up or why recollapse occurs. In the present study, we define recollapse of a treated vertebra, assess how common it is following percutaneous kyphoplasty, and investigate risk factors for the condition.

METHODS

In total, 203 consecutive patients who underwent percutaneous kyphoplasty were reviewed after an average 12.7 months to assess what proportion of cement-augmented vertebrae had recollapsed. Potential risk factors for recollapse included age, gender, body weight, body height, body mass index, treated level, duration of symptoms, follow-up duration, preoperative T-scores, surgical approach, the intravertebral cleft, contact of polymethyl methacrylate (PMMA) with endplates, cement volume, cement leakage, and midline vertebral body height. Stepwise multivariate linear regression was conducted to predict recollapse as quantified by midline vertebral height loss.

RESULTS

Overall, 38.9% of the augmented vertebrae recollapsed. In the recollapse group, the average midline vertebral height ratio and kyphotic angles statistically significantly changed during follow-up (P < 0.05). Pain scores decreased immediately after percutaneous kyphoplasty and generally remained low at follow-up. Significant predictors of midline vertebral height loss at follow-up included presence of an intravertebral cleft, postoperative vertebral height, and non-PMMA-endplate-contact. Together, these factors accounted for 28% of the variability in midline height loss.

CONCLUSIONS

Benefits of percutaneous kyphoplasty are partly offset by subsequent recollapse. Recollapse is greater if there is an intravertebral cleft, non-PMMA-endplate-contact and an increase in the post vertebral height.

Effects of Weekly Teriparatide Administration for Vertebral Stability and Bony Union in Patients with Acute Osteoporotic Vertebral Fractures

Study Design

An open-label, non-randomized prospective study.

Purpose

Teriparatide (TPTD) is known to be an antiosteoporotic agent that may accelerate the healing of fractures. This study was designed to investigate the effect of once-weekly TPTD administration on vertebral stability and bony union after acute osteoporotic vertebral fracture (OVF).

Overview of Literature

Once-weekly TPTD administration can lead to early vertebral stability and promote bony union of fractured vertebrae in patients with severe osteoporosis.

Methods

Forty-eight subjects with acute OVF were assigned to receive activated vitamin D3 and calcium supplementation or onceweekly subcutaneous injection of TPTD (56.5 μg) in combination with activated vitamin D3 and calcium supplementation for 12 weeks. Vertebral stability was assessed using lateral plain radiography. Vertebral height at the anterior location (VHa) and the difference in VHa {ΔVHa=VHa (supine position)−VHa (weight-bearing position)} were measured at baseline and 12 weeks after starting treatment. Bony union was defined as the absence of a vertebral cleft or abnormal motion (ΔVHa >2 mm).

Results

Although not significant, ΔVHa, indicating vertebral stability, tended to be lower in the TPTD group at 12 weeks (p =0.17). As for subjects with severe osteoporosis, ΔVHa at 12 weeks was significantly lower in the TPTD group than in the control group (mean ΔVHa: control group, 3.1 mm (n=15); TPTD group, 1.4 mm (n=16); p =0.02). The rate of bony union was significantly higher in the TPTD group than in the control group (control group, 40%; TPTD group, 81%; p =0.03).

Conclusions

Once-weekly TPTD administration may facilitate early bony union after acute OVF accompanied by severe osteoporosis.

Vertebral heights and ratios are not only race-specific, but also gender- and region-specific: establishment of reference values for mainland Chinese

This study established gender-specific reference values in mainland Chinese (MC) and is important for quantitative morphometry for diagnosis and epidemiological study of osteoporotic vertebral compressive fracture. Comparisons of reference values among different racial populations are then performed to demonstrate the MC-specific characteristic.

PURPOSE

Osteoporotic vertebral compressive fracture (OVCF) is a common complication of osteoporosis in the elder population. Clinical diagnosis and epidemiological study of OVCF often employ quantitative morphometry, which relies heavily on the comparison of patients' vertebral parameters to existing reference values derived from the normal population. Thus, reference values are crucial in clinical diagnosis. To our knowledge, this is the first study to establish reference values of the mainland Chinese (MC) for quantitative morphometry.

METHODS

Vertebral heights including anterior (Ha), middle (Hm), posterior (Hp) heights, and predicted posterior height (pp) from T4 to L5 were obtained; and ratios of Ha/Hp, Hm/Hp and Hp/pp. were calculated from 585 MC (both female and male) for establishing reference values and subsequent comparisons with other studies.

RESULTS

Vertebral heights increased progressively from T4 to L3 but then decreased in L4 and L5. Both genders showed similar ratios of vertebral dimensions, but male vertebrae were statistically larger than those of female (P < 0.01). Vertebral size of MC population was smaller than that of US and UK population, but was surprisingly larger than that of Hong Kong Chinese, although these two are commonly considered as one race. Data from different racial populations showed similar dimensional ratios in all vertebrae.

CONCLUSIONS

We established gender-specific reference values for MC. Our results also indicated the necessity of establishing reference values that are not only race- and gender-specific, but also population- or region-specific for accurate quantitative morphometric assessment of OVCF.

Correlations between posterior longitudinal injury and parameters of vertebral body damage

BACKGROUND

The posterior longitudinal ligament (PLL) is an important structure of spinal stability. The loss of vertebral body height, local kyphosis (LK), and canal compromise may lead to spinal instability. This study determined the correlations between injury of the PLL and the loss of vertebrae height, kyphosis, and canal compromise.

MATERIALS AND METHODS

A retrospective review of a thoracolumbar burst fracture database was conducted from January 2009 to December 2011. Patients were divided into an intact group and a disrupted group according to the status of the PLL. The loss of vertebral height, mid-sagittal canal diameter, and LK was measured. The anterior, middle, and posterior vertebral compression ratios (AVBCR, MVBCR, and PVBCR) and mid-sagittal diameter compression ratio (MSDCR) were calculated.

RESULTS

Forty-seven patients were included in the study, including 25 patients in the intact group and 22 patients in the disrupted group. There were significant differences in the AVBCR (t = -3.048, P = 0.004), MVBCR (t = -2.301, P = 0.048), PVBCR (t = -2.116, P = 0.040), and MSDCR (t = -4.095, P = 0.000) but no difference in the LK (t = 0.408, P = 0.686) between the two groups. There was a positive correlation between the injury of the PLL and the MSDCR (r = 0.428, P < 0.01), AVBCR (r = 0.372, P < 0.01), and PVBCR (r = 0.271, P < 0.05). There was no correlation between the injury of the PLL and the LK and MVBCR.

CONCLUSIONS

The MVBCR and LK are not predictive of a PLL injury. The MSDCR, AVBCR, and PVBCR were associated with a PLL injury.